Aaua microbiologist

Tuesday, September 26, 2017

MYCOLOGY - FUNGI GROWTH, PHYSIOLOGY AND METABOLISM

The growth of fungi as hyphae on or in solid substrates or as single cells in aquatic environments is adapted for the efficient extraction of nutrients, because these growth forms have high surface area to volume ratios.
Hyphae are specifically adapted for growth on solid surfaces, and to invade substrates and tissues.

They can exert large penetrative mechanical forces; for example, the plant pathogen Magnaporthe grisea forms a structure called an appressorium that evolved to puncture plant tissues The pressure generated by the appressorium, directed against the plant epidermis, can exceed 8 megapascals (1,200 psi).]

The filamentous fungus Paecilomyces lilacinus uses a similar structure to penetrate the eggs of nematodes.] The mechanical pressure exerted by the appressorium is generated from physiological processes that increase intracellular turgor by producing osmolytes such as glycerol. ]

Morphological adaptations such as these are complemented by hydrolytic enzymes secreted into the environment to digest large organic moleculessuch as polysaccharides, proteins, lipids, and other organic substratesinto smaller molecules that may then be absorbed as nutrients. The vast majority of filamentous fungi grow in a polar fashioni.e., by extension into one directionby elongation at the tip (apex) of the hypha.

Alternative forms of fungal growth include intercalary extension (i.e., by longitudinal expansion of hyphal compartments that are below the apex) as in the case of some endophytic fungi, or growth by volume expansion during the development of mushroom stipes and other large organs.] Growth of fungi as multicellular structures consisting of somatic and reproductive cellsa feature independently evolved in animals and plantshas several functions, including the development of fruiting bodies for dissemination of sexual spores (see above) and biofilms for substrate colonization and intercellular communication.

The fungi are traditionally considered heterotrophs, organisms that rely solely on carbon fixed by other organisms for metabolism. Fungi have evolved a high degree of metabolic versatility that allows them to use a diverse range of organic substrates for growth, including simple compounds such as nitrate, ammonia, acetate, or ethanol For some species it has been shown that the pigment melanin may play a role in extracting energy from ionizing radiation, such as gamma radiation; however, this form of "radiotrophic" growth has been described for only a few species, the effects on growth rates are small, and the underlying biophysical and biochemical processes are not known.
The authors speculate that this process might bear similarity to CO2 fixation via visible light, but instead utilizing ionizing radiation as a source of energy.

Wednesday, September 6, 2017

MYCOLOGY- CHYTRIDIMYCOTA

CLASS CHYTRIDIMYCETES
The  lowest  fungi  ever  studied  are  the  chytrids  of  the  family  Chytridiaceae  and  order Chytridiales. These are fungi that produce motile spores called zoospores (planogametes). The zoospores have a single posterior whip-lash like flagellum. The coenocytic thallus is made up of  simple  hyphae  and  the  thallus  is  well  developed.  The  conjugating  zoospores  soon develop/convert into a resting sporangium.
HABITAT:  They  are  prevalently  aquatic  but  some  are  found  in  soil,  while  a  good  number are  parasitic  in  the  tissue  of  angiosperms.  They  can  be  collected  and  cultivated  easily  using baits like fruits, pollen grain, boiled grass blades, egg albumen, cellophane, nectars of flowers, petals, insect excuvia, dead insects etc. Colonies are often inside or outside the bait
SOMATIC STRUCTURES OF CHYTRIDS 
In every primitive chytrids, the somatic structures are unicellular and holocarpic in fungi with holocarpic  somatic  structures,  the  same  somatic  structure  serves  for  both  vegetable  and reproductive purposes. Such fungi do not have respectable mycellium. In slightly higher ones, there  are  few  rhizoids  for  anchorage  and  nutrition.  The  sporogenous  part  of  the  thallus  is separated from the rest by a septum. On  the  evolutionary  trend  of  chytrids  the  somatic  structures  range  from  simple holocarpic  to  eucarpic.  It  also  ranges  from  simple  cell  to  simple  rhizoids,  to  complex rhyziods  and  extensive 
rhizomycellium.  The  mode  of  reproduction  ranges  from isogamous, ansogamous, gamentagial copulation to somatogamy as in N. ramosa.  Some  higher  chytrids  have  branches  of  rhizomycellium  and  there  are  some  with  well developed hyphae with pseudo-septa
Asexual reproduction in chytrids  This is by means of sporangia. The sporangium is initially filled with densely fluid in form of protoplasm  followed  by  cleavage.  The  protoplasm  becomes  separated  and  surrounds  the nucleus
ASEXUAL REPRODUCTION IN CHYTRIDS 
The zoospores can be released in a number of ways; 
1.  If the chytrid is inoperculate, the zoosporangium breaks. 
2.  If it is operculate, the operculum opens and the chytrids escape from the operculum.  The  zoospores  thus  liberated  would  swim  for  a  little  while  and  encyst,  loose  their  flagellum and  secretes  a  cell  wall  round  themselves.  After  some  time,  the  zoospores  geminate  as  their ancestors.  
SEXUAL REPRODUCTION IN CHYTIDS 
Sexual reproduction in chytrids is more complex and can take any of the following forms:
1.Planogametic copulation: Two swimming gametes conjugate and form a zygote. When the  two  swimming  gametes  are  equal  in  size,  the  copulation  is  said  to  be  isogamous. Quite  often  the  gametes  may  be  unequal  thus  called  planogametes.  The  conjugation  of two  unequal  gametes  leads  to  the  formation  of  a  motile  gamete  which  later  looses  the flagella  and  becomes  resting.  It  is  then  called  anisogamous.  The  non-motile  gamete  is usually  the  female,  larger  and  sedentary  while  the  motile  gamete  is  the  male.  The  non- motile female gametes are known as oogonia and the males are the antheridia 
2.Gamentagial  copulation: The body  of the  gamentagial of two  gametes  fuses to form a zygote.  The  entire  protoplasm  of  1  gamentaguim  fuses  with  another.  The  two  fuse together after which cleavage occurs and spores are formed.
3.Somatogamy:  The  gametes pass from the rhizoid form to form a zygote which forms a resting  gamete (spore) which  later  germinate and later release spores.  Fungi in the class  Chytridiomycetes  are  classified  into  4  orders  which  include;
(1).Chytridiales, 
(2) Blastodiales, 
(3) Monoble pharidiales  
(4) Harpochytridiales

MEET RINLOLA πŸ‘Œ A NAMS OO1 ASPIRANT

CAN WE MEET YOU?

I'm Akinrinlola Temitope
PKA Rinlola

A 300 level student of this noble department

TELL US A BIT ABOUT YOUR BACKGROUND?

I am from a family of 3 in which am opportune to be the eldest.

Am from Ondo state, Ondo city precisely

I started my elementary at St. Helens demonstrations then I attended Ondo Boys' High School both in Ondo.

WHAT POSITION ARE YOU VYING FOR?

Thank you, am vying for the position of the department President.

WHAT PROMPTED YOU TO SEEK TO BE NAMS PRESIDENT?

Have been in the department since 2015 and I know all what we want as a voice and have come to stand in gap.

WHAT ARE THE AGENDA FOR THE DEPARTMWNT?

Well, am sure you won't be expecting me to promise heaven and earth. Moreover, one of my major assignment is to bring opportunities to build up young minds into great minds; to kick out mediocrity and bring in superiority; to make you believe you don't have to think outside a box but makes you believe there's no BOX at all; to make you know you are relevant to the WORLD generally even if microbiology is not making you feel like one; to make you know that you are BORN REALIST; to make you know that you can if you think you can!!!
And on student welfarism, academic stimulations and  social vibes am believing I will be serving with wonderful set of geniuses along with myself if I emerge the winner. Inoculists, just watch out!!

YOUR HOBBY?

Just THINKING and Meditating

ANY LAST WORD?

Yes, I use this opportunity to thank you all and wish to remind you that if you believe, you will receive

Mantra:    "Power in a wrong hand leads to a black out.....#Peace"

God bless you
God bless Nigeria
God bless Ondo state
God bless AAUA
God bless NASS
God bless NAMS

Thank you

Monday, September 4, 2017

SMALLEST BACTERIA - MYCOPLASMA BY ASIFAT SAMSUDEEN OYEWOLE

        MYCOPLASMA - THE SMALLEST BACTERIA SPECIES

1.1 INTRODUCTION

Cell culture simply refers to the process of removing cells from an animal or plant and their subsequent growth in an artificial medium totally different from the cell internal environment. Cell culture is one of the important tool in medical and biological research especially in industrial biotechnology where they are used in the production of biologically active pharmaceuticals such as antibiotics and vaccines.

Any handling of cell culture from always poses the risk of Mycoplasma contaminations, either with eukaryotic cells from other cell cultures or more frequently with microbiological organism including yeast, fungi and bacteria.

Mycoplasma are the smallest know, fastidious and self-replicating bacterium without a cell wall around their cell membrane. They are about 0.3-0.8µm in diameter.

One of the major advantages of cell culture is the ability to manipulate the physico-chemical (i.e. temperature, pH, osmotic pressure, oxygen) and the physiological environment (i.e. hormone and nutrient concentrations) in which the cells propagate with the exception of temperature, the cell environment is controlled by growth medium (Gong et al., 2005).

While the physiological environment of the culture is not as well defined as it physico-chemical environment, a better understanding of the component of serum, the identification of the growth factors necessary for proliferation, and a better understanding of the micro environment of the cells in culture (i.e. the cell to cell interactions, diffusion of gases, interactions with the matrix) now allow the culture of certain cell lines in serum-free medium (Drexler et al., 2003).

1.2 TYPES OF CELL CULTURE

Primary Cell Culture: This is the first stage of cell culture where the cell is isolated from the tissue and proliferated given the appropriate conditions until they finally utilizes all the substrate available in the medium. At this stage the cell is ready to be subcultured.
Primary can be divide into two, this are:

Adherent or Anchorage Depapendent Cells: This are cell cultured which are shown to require an attachment for growth.

Suspension or Non Anchorage Dependent Cells: This are cell culture which do not require an attachment for growth or do not attach to the surface of the culture vessels.

Secondary Cell Culture : This is a type of cell culture where a finite cell is subcultured and allow to divide indefinitely (Harline et al., 2008).

2.1 HISTORY OF MYCOPLASMA

Mycoplasma is a genus of bacteria that lack a cell wall around their cell culture membrane. Without a cell wall, they are resistance to many common antibiotics such as penicillin or other beta-lactam antibiotics that target cell wall synthesis. They can be parasitic or saprotrophic. Several species are pathogenic in humans, including M. pneumoniae, which is an important cause of s typical pneumonia and other respiratory disorders. M. genitalium, are also believed to be involved in pelvic inflammatory diseases. Mycoplasma are the smallest bacteria cells yet discovered, they are anaerobes and are typically about 0.1µm in diameter (Robinson et al., 1998).

2.1.1 ORIGIN OF THE NAME

The term Mycoplasma, is coined from the Greek mykes (fungus) and plasma (formed), was first used by Albert Bernhard Frank in 1889 to describe an altered state of plant cell cytoplasm resulting from infiltration by fungus-like microorganisms imagined to have both cellular and acellular stages in their life cycles, which could explain how they were visible with a microscope but passed through filters which are impermeable to bacteria (Bielanski et al., 2009).

2.2 SPECIES OF MYCOPLASMA

There are more than 20 species isolated from contaminated cell lines, detailed observation on the identity of the contaminating species shows that the largest portion of infections is caused by Mycoplasma species, about 90-95% of the contaminant were identified as either M. orale, M. hyorhinis, M. arginini, M. fermentans or M. hominis.

Common microplasma species includes:
M. fermentans, M. genitalium, M. orale, M. hominis, M. salivarium, M. galliseptium, M. hyopneumoniae, M. arginine, M. hyorhinis (McGarrity et al., 2010).

3.1. INCIDENCE OF MYCOPLASMA CONTAMINATION IN CELL CULTURE

Mycoplasma were first isolated from a contaminated cell culture in 1956. One Mycoplasma species can grow up to 1000000 CFU per ml within three to five days in an infected cell culture. Eukaryotic cell culture contaminated with Mycoplasma species have titers in the range 1000000 to 10000000 organisms per ml. it has been known that about 100 to 1000 Mycoplasma attached to each infected cell. Primary cell culture and cultures in early passage have been reported to be less frequent contaminated than continuous cell lines. Several large series on thousands of cell cultures analyzed over decades (1960s – 1980s) found an incidence of 15%. Recent studies documented significantly on a smaller series to be in the region 15-35%, but also as high as 65-80%. The expanding application of cell lines in research and biotechnology and the increasing use of certain antibiotics (mostly penicillin and streptomycin which merely serve to mask but do not remove Mycoplasma) in routine culture have presumably led to the increase in Mycoplasma contamination in cell culture (Drexler et al., 2003).

3.2 MOST COMMON CONTAMINATING MYCOPLASMA SPECIES

While more than 20 species have been isolated from contaminated Cell lines, detailed investigations on the identity of the contaminating species showed that the largest proportion of infections is caused by relatively small number of Mycoplasma spp where about 90 – 95% of the contaminant were identified as either M. orale, M. hyorhinis, M. fermentans, or M. hominis. Generally, M.orale which is the most common Mycoplasma spp in the oral cavity of clinically normal humans, also represent the single most common isolate accounting for about 20 – 40% of all Mycoplasma infection in cell cultures. Other non-pathogenic Mycoplasma spp from normal human microbial flora of the oropharynx which are seen in cell culture are M. fermentans and M. hominis (McGarrity et al., 2010).

The bovine group of Mycoplasma such as M. arginine account for about another third of all strains isolated from cell cultures. Here the most frequent infected are M. arginine and M. hgyorhinis. These two species have a relatively wide host range especially M. arginine which is isolated from cattle, sheep, goat and other ruminant animals. This cell culture contaminant is thought to be derived from bovine sources. Bovine sera were not routinely and as strictly screened for Mycoplasma contamination. M. hyorhinis a common inhabitant of the nasal cavity of the swine, also account for the high proportion of the infections (Barile et al., 2010).

3.3 SOURCES OF MYCOPLASMA CONTAMINATION OF CELL CULTURE

Sources of Mycoplasma in cell culture is generalized in all the equipment, cells, and materials used in cell culture. They can be grouped into three main categories, which are Swine sources, Bovine and Human sources. Tissues specimen used to initiate cell cultures do not appear to represent the major sources of Mycoplasma infection. The frequent of infection in primary cell culture is low, in order of 1% (Armstrong et al., 2010). The high incidence of bovine sources predominantly M. arginini. Implicates fetal or newborn bovine serum. Most lot of serum provided for use in cell culture if not properly screened are contaminated with Mycoplasma spp (M.arginini) which were isolated to be around 25.40%. however, there is an high decrease in bovine serum contamination in the last decades owing to the appropriate effort of the suppliers with regards to other prevention and control measures by laboratory personnel, despite this measures serum lots absolutely free from Mycoplasma contamination cannot be guaranteed.

This is because the largest proportion of Mycoplasma species found in cell culture are of human origin, one may assume that laboratory personnel account for the major sources of contamination. In laboratories with contaminated cells, most or all cultures are positive with the same Mycoplasma species (Armstrong et al., 2010).
Mycoplasma infected cell lines themselves the most important source for further spread of the contamination. This is made possible owing to the ease of droplet generation during handling of cell cultures, the high concentration of Mycoplasma in infected cultures, and the prolonged survival of dried Mycoplasma cells. Mycoplasmas are spread by various laboratory equipment’s such as incubators, laminar flow hood, liquid nitrogen, etc. media or reagents that have been contaminated by previous use in processing Mycoplasma infected cells (Coecke et al., 2005).

3.3.1. DIFFERENT SOURCES FOR THE SPREAD OF MYCOPLASMA IN THE LABORATORY

McGarrity designed a model to find out how Mycoplasma spread in a laminar flow hood during a routine subculturing procedure. He intentionally infected a cell culture with Mycoplasma. After trypsinization of the infected culture in a laminar flow hood, live Mycoplasmas were isolated by the technician outside the flask, a hemocytometer, the pipettor, and outside of the pipette discard pan. Live Mycoplasma could be successfully recovered from the surface of the laminar flow hood even four to six days later. A clean culture that was subcultured once a week in the same weeks. These results show how quickly and easily Mycoplasma can spread and also against the possibility of contamination of most if not all of the other cultures after the entry of a single Mycoplasma infected culture into the laboratory. (McGarrity et al., 2010).

Currently, the major source of Mycoplasma contamination is infected cultures obtained from other research laboratories of commercial suppliers. Some of the major sources of Mycoplasma contamination are listed below:
Media, Sera or Reagent Contaminated with Mycoplasma
Mycoplasmas can pass into the filter membrane used in sterilizing cell culture media, sera and other reagents since they are too small and pliable due to the absence of a cell wall. Therefore, cell culture media and animal products used in cell culture should be considered major routes for Mycoplasma contamination. In the 1960s and 1970s, sera products were a very important primary source of infection, with reported contamination rates of 18% to 40%. Today, sera media obtained from reputable manufacturers are rarely the source of Mycoplasma contamination. However, it is still the responsibility of the end user to verify that the products they purchase have been adequately filtered, tested and certified as mycoplasma-free (Bolske, 2003).

It is common in most cell culture laboratories to use single 0.2µm pore size filter membranes to filter media or other solutions. However, this method is relatively safe for solutions with low levels of Mycoplasma. It is not recommended to filter raw animal-derived sera or products since the Mycoplasma contamination could potentially be high in them. To remove Mycoplasma with filtration, the method of filtering plays an important role. Low pressure differential (5-10 psi) is less likely to face Mycoplasma through a membrane than filter systems using 20 psi or higher pressure. Filters with 0.1µm pore size should be used instead of 0.2µm ones in the case of dubious conditions (Bolske, 2003).

Nonserile Supplies, Media and Solutions
Improper sterilization is a major source of biological contaminants. Packing too much into an autoclave or dry heat oven will cause uneven heating, resulting in pockets of nonsterile supplies. Using too short a sterilization cycle, especially for autoclaving volumes of liquids greater than 500 ml per vessel or solutions containing solids or viscous materials such as agar or starches are other mistakes resulting in incorrect sterilization. To accomplish sterility, the size, mass, nature and volume of the materials for sterilization have to always be considered. Storing sterilized supplies and solutions in a dust-and insect-free area is an obligation to prevent recontamination (Uphoff et al., 2002).
Laboratory Personnel
Laboratory personnel are considered a major source of Mycoplasma contamination. M.orale a species commonly found colonizing the human oral cavity and oropharynx, has been the leading contaminant in study after study. Two other human Mycoplasma species M.fermantans and M. salavarium, are also detected in contaminated cultures but at a much lower rate. Improper laboratory practices by laboratory personnel such as talking, sneezing or the use of mouth pipetting are other sources of human contamination.
In 1976, the role of laboratory technicians in Mycoplasma contamination in cell culture was proved. It was shown that the majority (80.6%) of technicians were carriers of mycoplasma, primarily M.salivarium the modes of spreading mycoplasma were evaluated by collecting aerosols generated via talking and sneezing from known Mycoplasma carriers on culture plates. M. salivarium can be transmitted during talking and sneezing of technicians in 6.2% and 37.5%, respectively. Street clothes and dirty lab coats are the major source of dust and aerosols. Negligence in wearing a clean lab coat and gloves is a major cause of spreading particles during routine cell culture processing. Furthermore, talking and sneezing also generate a significant amount of aerosols. It is highly recommended to avoid working without gloves since frequent hand washing can cause dry and flaky skin which is one of the main sources of particles (Steube et al., 2005)

Incubators

Incubators equipped with fans and air currents are another route for spreading Mycoplasma-containing particles during closing and opening of the internal door of the incubator. ”Good laboratory practices” are essential to avoid diffusion of Mycoplasma in the incubator and other laboratory devices such as the pipetman, pip aid and laminar flow. After droplet dispersion an incubator, bacteria are spread by aerosols (Koshimizu et al., 2000).

Liquid Nitrogen

Liquid nitrogen is another cause for spreading Mycoplasma. It is significant that Mycoplasma can survive in liquid nitrogen even without cryopreservation. While Mycoplasma do not proliferate in liquid nitrogen, they are able to contaminate cell cultures stored in liquid nitrogen. Therefore, storing cryovials in the vapor phase of nitrogen tanks is highly recommended (Gong et al., 2005).

Airborne Particles and Aerosols

Airborne particles and aerosols generated during culture manipulations are the greatest sources of Mycoplasma contamination. The diameter of microbeladen particles is generally 4 to 28µm and they settle at a rate of almost one foot per minutes in still air. As a result, the air in a settled, draft-free room or laboratory is nearly free of biological contaminants. However, as soon as people enter the room, particles that have settled down will be easily resuspended.

Some equipment and activities such as pipetting devices, vacuum pumps and aspirators, centrifuges, blenders, sonicators, and heat sources such as radiators, ovens refrigerators and freezers generate microbial particles and aerosols. Another source of particles and aerosols is experimental animals whose house and care facilities should be kept far from cell culture areas (Bolske, 2003).

Overuse of Antibiotics

It is a common particles in research laboratories to use antibiotics in cell cultures to avoid microbial contamination. The consequence of overuse of antibiotics is concealment of the poor aseptic technique and it is a major cause for Mycoplasma contaminated cultures. Overuse of antibiotics can also lead to antibiotics resistance. Veterans of cell culture insist on doing cell culture without antibiotics to avoid the problems (McGarrity et al., 2010).

Improper Sealing of Culture Dishes

Another way of entering microbial contamination in flasks, plates and dishes is improper seal of cultures dishes. The route for microbial contamination is provided when the top and bottom side walls of dishes or flask and their caps become wet and microbes transfer by capillary action of the wet surface (Hay R. J. et al., 2002)

Other Mycoplasma Contamination Cell Cultures

A Mycoplasma-infected cell culture is a major source of Mycoplasma contamination of other cell cultures in the lab. To avoid Mycoplasma contamination in cell cultures, it is recommended to test the new cell lines which are obtained from an outside source. A single Mycoplasma contaminated cell culture is enough to endanger other cell culture in the lab. The contamination can spread by means of aerosols and particles generated during the handling of the Mycoplasma infected cell culture. So, working with only one cell culture at a time and preparing separate media and reagents for each individual cell lines can avert Mycoplasma contamination. A good cell culture practice and regular testing of all new cell culture can decrease the risk of Mycoplasma contamination (Uphoff C. C. et al., 2001).

3.4. EFFECTS OF MYCOPLASMA CONTAMINATION

Mycoplasma infections can have a myriad of different effects on the contaminated cell cultures. However, this multitude of different effects does not affect the various cells in the same manner and to the same degree. Many Mycoplasma species produce severe cytopathic effects while others may cause very little overt cytopathology. There can be qualitative and quantitative differences in the same parameter, depending on the infecting Mycoplasma species, the culture conditions, the type of the infected cell culture, the intensity and duration of the infection, an additional infection with viruses, and other parameters. Thus, contaminations can interfere with virtually every parameter measured in cell cultures during routine cultivation or in experimental investigations (Coecke et al., 2005)

Consequently, the mycoplasmas in these cultures cannot simply be ignored or regarded as harmless bystander organisms. Besides the loss of an important culture, in the worst case all experiments might be influenced by the infections and artefacts are produced. Because of the virtually unlimited number of reported Mycoplasma effects on cultured cells, only some of the most important parameters have been listed here in order to highlight the diversity of possible effects (Berile et al., 2010).
10,000x (Gong et al., 2005).

One of the main reasons for the more or less severe cytopathic effects on cell cultures is the consumption of nutrients and basic components of the cellular metabolism, e.g. nucleic acid precursors, amino acids, vitamins, lipids, cholesterole etc. by the Mycoplasmas. Due to their low metabolic capabilities, their unefficient energy gain, and the high number of Mycoplasmas in the cell culture, those compounds can be used up rapidly. The nonoxidative degradation of the compounds also leads to an alteration of the pH value in the culture medium. The pH can be decreased by the formation of acids by Mycoplasmas using the fermentative metabolic pathways. On the other hand, arginine-hydrolyzing Mycoplasma (e.g. M. arginini, M. hominis) can increase the pH value due to the production of ammonia, which is also a highly toxic agent inhibiting cell growth. Additionally, activity of Mycoplasma arginine deiminase as well as Mycoplasma uptake and depletion of the growth medium were shown to inhibit cell proliferation and to induce apoptosis in cell lines. As visible effects, the cells show an abnormal growth rate, a decreased viability, adherent cells sometimes detach from the cell culture vessel surface, and granules are formed in the cells (Gong et al., 2005).
The depletion of arginine might also be a reason for chromosomal aberrations, because this basic amino acid is a major component of the histones in the nucleus. Another cause of chromosomal and genetic alterations and growth inhibition might be the competition of Mycoplasma and eukaryotic cells for nucleic acid precursors. Chromosome breakage, multiple translocation events, and numerical chromosome changes were described in various cell cultures infected with different Mycoplasma species. Eukaryotic DNAs and RNAs are degraded by exo- and endonucleases, which are produced and exported by Mycoplasmas. Sokolova et al., (1998), showed for different lymphocyte and epithelial tumor cell lines that inhibition of proliferation and increased cell death, accompanied by DNA fragmentation and the morphological features of apoptosis was caused by mycoplasma infections. Similar DNA fragmentation and loss of chromosomal DNA was also observed by Rawadi et al., (1996) in M. fermentans-infected monocytic cell lines. The cytocidal effect was assigned to a nonlipid-associated protein fraction.
One of the nucleotide-transforming enzymes is the uridine phosphorylase which inactivates the artificial bromodeoxyuridine (BrdU). BrdU is toxic for eukaryotic cells and added as thymidine analogue for the selection of cells with a thymidine kinase (TK) defect. Cells with normal TK activity phosphorylate and incorporate BrdU and will die. Cells with a TK defect which are used for cell fusion experiments grow in the presence of BrdU. In the presence of mycoplasmas, BrdU is degraded and the eukaryotic cells survive even though they do not possess a TK defect (Sokolova et al., 1998).

Mycoplasma proteins alter a number of eukaryotic properties in different manners. Rawadi et al., (1996) showed that heat-inactivated Mycoplasma particles induced the inflammatory cytokines interleukin 1 (IL-1), IL-6, and tumor necrosis factor in monocytes and THP-1 cells (14). M. fermentans also induced IL-10 in human monocytes. The secretion of immunoglobulins was altered in B-cells, as well as the expression of various colony-stimulating activities (e.g. granulocyte-monocyte colony stimulating factor) and the induction of interferon expression.
Another example for the detrimental effects of Mycoplasma contaminations is the impact on virus propagation in cell cultures. The virus production can be decreased by suppression of metabolism and growth of the cells connected with partially severe cytopathic effects, and arginine depletion by arginine oxidizing Mycoplasmas. Decreased yields can be found with arginine requiring viruses, such as Herpes simplex, vaccinia, adeno-viruses and several others. Increased virus yields can be obtained due to interferon-α inhibition, leading to diminished cell resistance. On the other hand, interferon activity can also be induced or stimulated by Mycoplasma infection. For example Acholeplasma species lipoglycans have endotoxin-like activities that induce interferon activity leading to resistance against some viruses in vitro or in vivo (Rawadi et al., 1996).

The few examples out of the nearly endless array of possible effects of Mycoplasma infections on cell cultures can only give a percursory idea of the very complex relationship between Mycoplasma and eukaryotic cells. Thus, any experimental result from mycoplasma infected cell cultures may rise prima vista substantial doubts (Sokolova et al., 1998).

3.5 DETECTION OF MYCOPLASMA CONTAMINATION

Mycoplasma infections of cell cultures can be highly diverse and no universal effect can be observed which may serve as an indicator for a contamination. Thus, special techniques were developed to detect Mycoplasma in cell cultures. During the pre- PCR era many methods were developed based on microbiological culture, e.g. staining techniques, electron microscopy, biochemical and immunological tests, and recently some hybridization assays (Drexler et al., 2002).
Many of the assays are relatively elaborate and time consuming, applicable only to a portion of the contaminating mycoplasmas, exhibit a low sensitivity, or the interpretation is subjective and fault-prone, or special equipment is necessary.
One of the first and still one of the officially approved (European Pharmacopeia) assays is the microbiological culture method. In this test, an aliquot of the cell culture supernatant is added to rich liquid mycoplasma medium, cultivated for a few days and subsequently transferred to agar plates with the same medium components. The plates are incubated for up to two weeks aerobically at 37°C. In case of positive samples, typical small colonies (ca.100 – 400μm in diameter) often with a “fried eggs” appearance comprising a dense center and a brighter corona appear on the agar plates. The test is sensitive, reliable, and robust for monitoring cell culture contaminations. Nevertheless, some strains of M. hyorhinis grow poorly or not at all on those media. We found that a certain number of M. hyorhinis strains grow indeed on the media, but in a number of cases the growth is not supported (Drexler et al., 2002).

The dense growth and even confluence of colonies indicative of a high Mycoplasma titer. The colonies show the tell-tale “fried-egg” appearance. Original magnification 100x, (Drexler et al., 2002).

A second detection method recommended by the European Pharmacopeia is the DNA fluorochrome staining (4´,6-diamidino-2´-phenylindole-dihydrochloride [DAPI] and Hoechst 33258 stain). This assay is relatively easy and rapid to perform. But the results are sometimes difficult to interpret and some experience is definitely necessary. Especially when the cell culture is not in a good condition, mis-interpretations are frequent. The sensitivity and specificity of the direct DNA staining procedure can be highly increased by use of indicator cell lines. In this indirect DNA staining method, supernatant from the cell culture to be tested is added to a Mycoplasma-free adherent cell culture (e.g. Vero B4, NIH- 3T3 or 3T6 cell lines). The cells are grown in vessels containing sterile cover slips. After growth for several days to approximately half-confluency, the cover slips are washed and stained with the fluorochrome. Mycoplasma infections can be detected very efficiently, but again, the test is relatively-time consuming and Mycoplasmas are cultured in the laboratory, which may lead to further spread of contaminations (Drexler et al., 2002).
Nowadays, a number of assays are available, which can detect almost all Mycoplasma contaminations within at most two days, including one or more incubation steps over several hours. These techniques are all indirect tests, which determine or visualize Mycoplasma components or enzyme activities.
One of the most prevalent assays for the detection of Mycoplasma contaminations is the polymerase chain reaction (PCR) technique. The test is easy to perform, sensitive, specific, fast, reliable, and cost effective. Most of the 16S rRNA sequences of Mycoplasma are known and can be used to create primers for the amplification of specific DNA fragments. The primer design defines the specificity of the PCR reaction.
Oligonucleotides from variable 16S rRNA regions are usually specific for a limited number of Mycoplasma species. Sequences from the 16S-23S intergenic regions can be used for the detection of single Mycoplasma species. For the detection of Mycoplasma in cell cultures, the specificity of the primers needs to be broad enough to detect Mycoplasma as well as Acholeplasma species. On the other hand, the specificity should be narrow enough to exclude amplification of sequences from other common bacteria, which might be contaminations of the PCR reagents (Uphoff et al., 2003).
However, some more important general aspects should be considered when performing this technique.
The sensitivity of the procedure makes it susceptible to contaminations with the target DNA which is present in high amounts after the first amplification of Mycoplasma-specific DNA. Therefore, extreme care has to be taken to prevent carry-over of target DNA fragments. This is especially the case when a nested PCR is performed.
The PCR should be performed with extracted DNA and not with a crude lysate of the cell culture supernatant, because the cell culture components might contain inhibitors of the Taq polymerase.
The use of antibiotics in cell culture should be minimized and the cell cultures should be cultured without antibiotics for several passages or at least two weeks to allow the Mycoplasmas to grow to detectable amounts or to ensure that no residual Mycoplasma DNA is left in the culture medium.
It is of note that a positive result of the PCR does not necessarily indicate viable contaminants, especially after a mycoplasma elimination procedure using antibiotics against mollicutes.
Thus, the PCR method should be properly established and all assays should be performed with the utmost care (Uphoff et al., 2003).
The PCR can be performed with a single round of amplification or as nested PCR with two primer pairs. The second method increases the sensitivity and the specificity. But one of the drawbacks of the nested PCR is the possible generation of false positive results due to contamination with target DNA. For the routine cell culture technology, the PCR is satisfactory to detect Mycoplasma contaminations, because the titer of the Mycoplasmas in the cell cultures is sufficiently high to be detected by the PCR. Special conditions, e.g. after Mycoplasma elimination procedures or for the detection of Mycoplasma in cell culture products like FBS, the nested PCR might be of advantage. Another possibility to increase the sensitivity of the assay is to perform a reverse transcription PCR (RT-PCR) to detect ribosomal RNA which is more abundant in the cells than the rRNA-coding DNA. However, the latter option is clearly more labor-intensive. In summary, we would suggest to perform a single PCR with genomic DNA for routine cell culture and to test the cultures frequently for contaminations. Several PCR kits are commercially available, e.g. from ATCC, Minerva Biolabs, Roche, Stratagene, TaKaRa Bio, and detailed descriptions and positive and internal control DNAs for the establishment of a PCR can be obtained from the DSMZ (Uphoff et al., 2003)

Shown is an ethidium bromide-stained gel containing the reaction products following PCR amplification. Two paired PCR reactions were performed: one reaction containing an aliquot of the sample only and the second contained the sample under study plus a control DNA as internal standard. Cell line A is specifically positive for Mycoplasma and also for the internal control whereas cell line B is specifically negative for Mycoplasma being positive in the internal control (Uphoff et al., 2003).

There are also newly developped assays based on fluorescence in situ hybridization (FISH) and on ATP generation (Cambrex, UK) detected by fluorescence microscopy and luminometer, respectively. Until now, no published data are available concerning the sensitivity, specificity, and the accuracy of both assays applied in routine cell culture. But preliminary results are promising concerning the above mentioned parameters and in particular with regard to the speed of the assays. The FISH test takes about two to three hours and results from the luminescence test can be generated within 20 minutes.
All described methods may fail when cell cultures are tested which were treated with antibiotics. In general, all treated cell lines should be cultured for at least two weeks without any antibiotics before the cells are retested. Both, false negative as well as false positive results may occur. PCR and other assays depending on the determination of DNA or RNA can produce false positive results, because residual DNA or RNA is detected, in the absence of viable Mycoplasmas. False negative results are produced when the titers of the Mycoplasmas are below the detection levels of the assays. We recommend to perform two or even three independent assays for the detection of Mycoplasma in cell lines which newly arrive in the laboratory.The cells should be kept isolated in a quarantine laboratory until all tests show that the cells are free from Mycoplasma, if possible at all. During continuous culture one sensitive assay should be performed regularly to monitor the cell cultures (Harline et al., 2008).

3.6 ERADICATION OF MYCOPLASMA CONTAMINATION

Mycoplasmas cannot be regarded as harmless bystander organisms in cell cultures. Thus, the best way to get rid of the infections is to autoclave the culture and to replace it with a new and uncontaminated culture. Unfortunately, the contaminated cell culture may often be unique in some regards and may not be replaceable. In these cases, the Mycoplasmas have to be eliminated without affecting the eukaryotic cells. Over the years, a number of elimination methods had been developed, applying physical, chemical, immunological and chemotherapeutic treatments. The treatments are not restricted to cell cultures only, but also for surfaces, cell culture media and supplements. Methods include heat treatment, filtration, exposure to detergents, culture in the presence of 6 methylpurine deoxyriboside, passage through nude mice, antibiotic treatment, and others.Regarding the treatment of cell cultures, many of the methods are laborious or not efficient. Additionally, some of the elimination methods had been investigated only in experimentally infected cell cultures. This might not necessarily reflect the complex nature of a chronically infected culture and the occurrence of intracellular Mycoplasma also has to be considered. From our experience, treatment with several specific anti-Mycoplasma, antibiotics is the method of choice for infected cell cultures. Usually, the antibiotics are also active or even might be accumulated in the eukaryotic cells (Rawadi et al. 1995).
As Mycoplasmas are very unusual bacteria in many respects, this is manifested also in the susceptibility against chemotherapeutic agents. Many of the commonly applied antibiotics are not effective against Mycoplasma, due to the lack of the antibiotic target (e.g. penicillins, streptomycin, etc.). On the other hand, although not killing the Mycoplasmas, some antibiotics might suppress their growth and thus mask the presence of the infectants. Beside the enforcement of strictly sterile cell culture technique and the development of resistances, this is one reason not to apply antibiotics prophylactically in routine cell culture (Rawadi et al. 1995).
Until now, three groups of agents were shown to be highly active against Mycoplasmas: Macrolides, Tetracyclines, and Quinolones. Macrolides and tetracyclines both inhibit protein synthesis, but bind to different subunits of the ribosomes. The quinolones (also named fluoroquinolones) inhibit the bacterial gyrase, an enzyme which is essential for the DNA replication. The quinolones tested in cell cultures are: ciprofloxacin (brand name Ciprobay 100, Bayer, Germany), enrofloxacin (Baytril, Bayer), sparfloxacin (Aventis Pharma, Ireland), and an unpublished quinolone reagent available as Mycoplasma Removal Agent (MRA, ICN, Eschwege, Germany). The macrolide Tiamulin and the tetracycline Minocycline are available as BM-Cyclin from Roche (Mannheim, Germany) and are applied subsequently in one treatment (Rawadi et al. 1995).

Brand nameGeneric nameAntibiotic categoryBM-CyclinTiamulin
MinocyclineMacrolide
TetracyclineCiprobayCiprofloxacinFluoroquinoloneBaytrilEnrofloxacinFluoroquinoloneZagamSparfloxacinFluoroquinoloneMRAFluoroquinolonePlasmocinTetracycline
FluoroquinoloneSource: European Pharmacopeia (2002).

In our hands the curation efficiency of the antibiotic approaches varied between 66 and 85%, depending on the antibiotic used. But these numbers do not only reflect the killing of the Mycoplasmas, but also include the loss of the culture, due to growth inhibition of the eukaryotic cells. The loss of cultures is frequently seen when the cells are heavily infected and already in a very bad condition (3-11% of treated cultures, depending on the antibiotic) (Harline et al., 1993).
In these cases the antibiotics might be the last hit to kill the eukaryotic cells. On the other hand, resistances against one antibiotic (7-24% of treated cultures, depending on the antibiotic) can be overcome by application of antibiotics from another group. Another combination product developed for the eradication of Mycoplasma from cell cultures is Plasmocin (InvivoGen, San Diego, USA). It contains an unpublished antibiotic against protein synthesis (presumably one of the above mentioned) and a quinolone, which are used simultaneously. No published data are available for this treatment until now. Pretreatment of heavily infected cultures with other methods, e.g. exposure to hyperimmune antimycoplasma serum, co-culture with macrophages, or washing the cells with surfactincontaining solutions, might be helpful, because the bulk of the Mycoplasmas can be eliminated.
The more recently developed membrane-active peptides, e.g. alamethicin, dermaseptin B2, gramicidin S, and surfactin, are highly efficient in pure Mycoplasma cultures, but in the presence of serum, the activities are decreased. Thus, the concentrations and treatment times required for the elimination of Mycoplasmas from cell cultures are toxic to the eukaryotic cells (Harline et al., 1993).

3.7 PREVENTION OF MYCOPLASMA CONTAMINATION

The prevention of Mycoplasma contamination can be divided into three categories: cell culture facility, cell culture procedures, and operator technique. While the measures proposed will not automatically prevent any mycoplasma infection, they will significantly decrease the probability of its occurrence. Such efforts are also of great importance for the prevention of cross-contamination with other eukaryocytic cells which in the majority of cases appears to be the result of inadequate cell culturing as well (Uphoff et al., 2001).
Cell Culture Facility
Any sterile cell culture work should be performed in a vertical laminar-flow biohazard hood. It is important to disinfect all work surfaces before and after culture manipulations, including the various devices entering the laminar flow hood. Mycoplasmas are very sensitive to most disinfectants, but have shown extended survival in a dried state (Ben-Menachem et al., 2001).
Cell Culture Procedures
Cell culture laboratories should establish effective and regular Mycoplasma testing procedures in the form of a routine screening program for all forms of microbial contamination, including Mycoplasmas. For Mycoplasma screening, we recommend PCR analysis. Sera, media and supplements (and also cell lines whenever possible) should be purchased from reputable suppliers that adequately test for Mycoplasma contamination. All incoming cell lines should be quarantined until the contamination status is verified. Mycoplasma-free cultures should be segregated from infected cultures by time and place of handling. Reagents for the two sets of cultures should be separate. The general use of antibiotics is not recommended except in special applications and then only for short durations. Use of antibiotics may lead to lapses in aseptic technique, to selection of drug-resistant organisms, and to delayed detection of low-level infection by either Mycoplasmas or other bacteria. Master stocks of Mycoplasma-free cell lines should be frozen and stored to provide a continuous supply of cells should working stocks become contaminated. Actively growing Mycoplasma-infected cell lines should be discarded or treated with mycoplasmacidal measures as quickly as possible in order to prevent lateral spread (Koshimizu et al., 2000).
Operator Technique
Strict adherence of the cell culturist to general aseptic culture techniques is a fundamental aspect in mycoplasma control. Cell culturists should continually be aware of the possibility of contaminating clean cultures with aerosols from Mycoplasma-containing cultures which are handled in the same area. For example, the following procedures with liquid media generate droplets: pipetting, decanting, centrifuging, sonicating. These relatively large droplets settle into the immediate environment where they may remain viable for some time (Armstrong et al., 2010).



CHAPTER FOUR
4.1 CONCLUSION

Since it has been observed that the commonly used cell culture reagents and enzymes such as bovine, serum and porcine trpsin respectively are carriers of Mycoplasma species, hence culture reagent should be properly screened and test for contamination before they are employed in cell culture. However, experimental animals should be kept far form cell culture areas, since they are sources of Mycoplasma contamination.
Cell culture remains an important tool in biological and medical research because of their application in genetic engineering, biotechnology and medicine (especially in the treatment of infectious diseases). Hence, standard control measure should be taken to avoid the risk of Mycoplasma contamination.

REFERENCES

Armstrong, S. E., Mariano, J. A. and Lundin, D. J. (2010). The scope of Mycoplasmacontamination within the biopharmaceutical industry. Biological. 38(2):211213

Barile, M. F. and Rottem, S. (2003). Mycoplasmas in cell culture. Rapid Diagnosisof Mycoplasmas (Kahane, I. and A. Adoni, eds), Plenum Press, New York,155-193.

Ben-Menachem, G., Mousa, A., Brenner, A., Pinto, F., Zähringer, U. and Rottem S.(2001). Choline deficiency induced by Mycoplasma fermentans enhancesapoptosis of rat astrocytes. FEMS Microbiol Letters. 201: 157-162.

Bielanski, A. and Vajta, G. (2009). Risk of contamination of germplasm duringcryopreservation and cryobanking in IVF units. Human Reproduction.24(10):245-267.

Bolske, G. (2003). Survey of Mycoplasma infections in cell cultures and acomparison of detection methods. Zentralbl. Bakteriol. Mikrobiol. Hyg. Ser.269: 331-340.

Coecke, S., Balls, M., Bowe, G., Davis, J. and Gstraunthaler, G. (2005). Guidanceon good cell culture practice, a report of the second ECVAM task force ongoodcellculture practice. Alternative Laboratory Animal. 33(3):261-287.

Drexler, H. G. and Uphoff, C. C. (2002). Contamination of cell cultures,mycoplasma. In The Encyclopedia of Cell Technology (Spier, E., B.Griffiths, and A.H.Scragg, eds), Wiley, New York, 609-627.

Drexler, H. G., Dirks, W. G., Matsuo, Y. and MacLeod, R. A. F. (2003). Falseleukemialymphoma cell lines: An update on over 500 cell lines. Leukemia17: 416-426.

European Pharmacopeia. (2002). 4th Edition. Biological Tests – Mycoplasmas. 128-131.

Gong, H., Zölzer, F., von Recklinghausen, G., Rössler, J., Breit, S., Havers, W.,Fotsis, T. and Schweigerer, L. (2005). Arginine deiminase inhibits cellproliferation by arresting cell cycle and inducing apoptosis. Biochem.Biophys. Res. Comm. 261: 10-14.

German Collection of Microorganisms and Cell Cultures: Catalogue of Human andAnimal Cell Lines (2012).

Harline, H. and Gajewski, T. F. (2008). Diagnosis and treatment of Mycoplasmacontaminated cell cultures, Current Protocol on Cell culture. 2: 12-18

Hay, R. J., Macy, M. L. and Chen, T. R. (2002). Mycoplasma infection of culturedcells. Nature. 339: 487-488.

Koshimizu, K. and Kotani, H. (2002). In Procedures for the Isolation andIdentification of Human, Animal and Plant Mycoplasmas. Nakamura, M.,ed., Saikon, Tokyo, 87-102.

McGarrity, M. F., Vanaman, V. and Sarama, J. (2010). Cytogenetic effects ofMycoplasma infection of cell cultures: a review. In Vitro. 20: 1-18.

Rawadi, G., Roman-Roman, S., Castedo, M., Dutilleul, V., Susin, S., Marchetti, P., Geuskens, M. and Kroemer, G. (1996). Effects of Mycoplasma fermentans onthe myelomonocytic lineage: Different molecular entities with cytokineinducing and cytocidal potential. J. Immunol. 156: 670-678.

Robinson, L. B., Wichelhausen, R. H. and Roizman, B. (1956). Contamination ofhuman cell cultures by pleuropneumonia-like organisms. Science. 124:1147-1148.

Sokolova, I. A., Vaughan, A. T. M. and Khodarev, N. N. (1998). Mycoplasmainfection can sensitize host cells to apoptosis through contribution ofapoptotic-like endonuclease(s). Immunology Cell Biology. 76: 526-534.

Steube, M. Tümmler, M. Voges, B. Wagner, and Drexler, H. G. (2005). Sensitivityand specificity of five different Mycoplasma detection assays. Leukemia.6: 335-341.

Uphoff, C. C. and Drexler, H. G. (2002). Detection of Mycoplasma inleukemialymphoma cell lines using polymerase chain reaction. Leukemia.16:289-293.

Uphoff, C. C. and Drexler, H. G. (2001). Prevention of Mycoplasma contaminationin leukemia-lymphoma cell lines. Human Cell. 14: 244-247.

Uphoff, C. C., Merkhoffer, Y. and Drexler, H. G. (2003). A new method for therapiddetection of Mycoplasma contaminations in leukemia cell lines.Hematol. J. 4: 260-280.

Sunday, September 3, 2017

MEET JOHN JAY, A NAMS OO1 ASPIRANT

CAN WE MEET YOU SIR ?

My name is AKANDE JOHN JOY
pka  JOHN JAY

Am a 300L student of this noble department, Microbiology.

State: Osun state
Town: Ile ife

Primary sch: Bright Future Group of School, Modakeke Ile ife

Secondary sch: Adventist High schools, Lagere - Ile ife

Hobby: I love playing instruments so much ( Bass, guitar, lead guitar, Drums, talking drum, keyboard, sax)
Reading, Playing games, Watching series movie

Favorite quote: ```setback shouldn't set you back, for they are stepping stones. So step on the stone and move upward and forward``` by Samuel Koranteng Pipim

POSITION YOU ASPIRE FOR?

Am vying for the post of the President (NAMS)

WHAT PROMPTED YOU TO TAKE UP THE CHALLENGE?

Well, i don't see it as a challenge, what prompted me to seek for this post is what I called VISION'17, that is uplifting NAMS AAUA CHAPTER to the 21st century arena among other universities in Nigeria.

SO WHAT ARE YOUR AGENDAS ?

What I will be doing for this association is gargantua, first and foremost is placing the agitations of my fellow inoculists as my number one priority when I emerge.

Moreso, it is lugubrious that in this century we are, we're (NAMS AAUA) still trying to meet up with our counterpart in other universities in all ramifications (laboratory standard, lecture-wise, course outline and so on), so when I emerge as the president the needed steps will be taken.

Furthermore, there will be free WiFi for all inoculist for there projects, research work, online reading and so on if I emerge as the President

There are lots in stock for us.....

I can only achieve this through the help of God and your support and vote...

WHAT WILL YOU LIKE TO BE IN THE FUTURE?

Future ambition  is To be a pathologist, studio manager, one of the greatest instrumentalists

YOUR LAST WORDS

To all the Greatest Inoculist, I wish to say that you guys have been ever very supportive all this years, and I wish to tell you that we can do it better again

Thanks,
God bless You All....

GREATEST INOCULIST !!!
INCUBATE

MYCOLOGY- STRUCTURE OF FUNGI

              STRUCTURE OF FUNGAL
Fungal Hyphae Cells
1- Hyphal wall
2- Septum
3- Mitochondrion
4- Vacuole
5- Ergosterol crystal
6- Ribosome
7- Nucleus
8- Endoplasmic reticulum
9- Lipid body
10- Plasma membrane
11- SpitzenkΓΆrper
12- Golgi apparatus
                Shared features:
1.With other eukaryotes: Like other eukaryotes, fungal cells contain membrane-bound nuclei with chromosomes that contain DNA with noncoding regions called introns and coding regions called exons. In addition, fungi possess membrane-bound cytoplasmic organelles such as mitochondria, sterol-containing membranes, and ribosomes of the 80S type. They have a characteristic range of soluble carbohydrates and storage compounds, including sugar alcohols (e.g., mannitol), disaccharides, (e.g., trehalose), and polysaccharides (e.g., glycogen, which is also found in animals]).
2.With animals: Fungi lack chloroplasts and are heterotrophic organisms and so require preformed organic compounds as energy sources.
3.With plants: Fungi possess a cell wall and vacuoles. They reproduce by both sexual and asexual means, and like basal plant groups (such as ferns and mosses) produce spores. Similar to mosses and algae, fungi typically have haploid nuclei.
4.With euglenoids and bacteria: Higher fungi, euglenoids, and some bacteria produce the amino acid Llysine in specific biosynthesis steps, called the -aminoadipate pathway]
5.The cells of most fungi grow as tubular, elongated, and thread-like (filamentous) structures and are called hyphae, which may contain multiple nuclei and extend at their tips. Each tip contains a set of aggregated vesiclescellular structures consisting of proteins, lipids, and other organic moleculescalled SpitzenkΓΆrper. Both fungi and oomycetes grow as filamentous hyphal cells.In contrast, similar-looking organisms, such as filamentous green algae, grow by repeated cell division within a chain of cells.
6.In common with some plant and animal species, more than 60 fungal species display the phenomenon of bioluminescence]
                 Unique features:
1.Some species grow as single-celled yeasts that reproduce by budding or binary fission. Dimorphic fungi can switch between a yeast phase and a hyphal phase in response to environmental conditions.
2.The fungal cell wall is composed of glucans and chitin; while the former compounds are also found in plants and the latter in the exoskeleton of arthropods, fungi are the only organisms that combine these two structural molecules in their cell wall. Unlike cell walls in plants and the oomycetes, those in fungi do not contain cellulose.

MYCOLOGY

                 WHAT ARE FUNGI?

Fungi can be single celled or very complex multicellular organisms. They are found in just about any habitat but most live on the land, mainly in soil or on plant material rather than in sea or fresh water.   A group called the decomposers grow in the soil or on dead plant matter where they play an important role in the cycling of carbon and other elements. Some are parasites of plants causing diseases such as mildews, rusts, scabs or canker. In crops fungal diseases can lead to significant monetary loss for the farmer. A very foot, ringworm and thrush

Fungi (Singular: fungus) are classified within their own kingdom - The Kingdom Fungi, while some are in The Kingdom Protista. A fungus is neither a plant nor an animal. It is similar to a plant, but it has no chlorophyll and cannot make its own food like a plant can through photosynthesis. They get their food by absorbing nutrients as from their surroundings. 

Kingdom  Fungi includes mushrooms, rusts, smuts, puffballs, truffles, morels, molds, and yeasts, and thousands of other organisms and microorganisms. They range from microscopic single-celled organisms, such yeast, to gigantic multicellular organisms.  

Many fungi play a crucial role in decomposition (breaking things down) and returning nutrients to the soil. They are also used in medicine, an example is the antibiotic penicillin, as well as in industry and food preparation. 

For a long time fungi were classified as plants, mainly because of their similar lifestyles - both are seen to grow in soil and are sessile (permanently attached; not moving). Plant and fungal cells both have a cell wall, while cells from the animal kingdom don't. Fungi are thought to have diverged from the plant and animal kingdoms about one billion years ago

GENERAL CHARATERISTICS OF FUNGI

1. Nutrition. -Heterotrophic (lacking photosynthesis), feeding by absorption rather than ingestion.

2. Vegetative status. -On or in the substratum, typically as a non-motile mycelium of hyphae showing internal protoplasmic streaming. Motile reproductive states may occur

3. Cell wall         -Typically present, usually based on glucans and chitin, rarely on glucans and cellulose (Oomycota).

4.Nuclear status.     -Eukaryotic, uni- or multi- nucleate, the thallus being homo- or hetero- karyotic, haploid, dikaryotic or diploid, the latter usually of short duration (but exceptions are known from several taxonomic groups).

5.  Life cycle -  Simple or, more usually, complex. 

6. Reproduction   - The following reproductive events may occur: sexual (i.e. nuclear fusion and meiosis) and/or parasexual (i.e. involving nuclear fusion followed by gradual de-diploidization) and/or asexual (i.e. purely mitotic nuclear division)

7.Propagules      -These are typically microscopically small spores produced in high numbers. Motile spores are confined to certain groups. 

8.Sporocarps     -Microscopic or macroscopic and showing characteristic shapes but only limited tissue differentiation.

9. Habitat  - Ubiquitous in terrestrial and fresh- water habitats, less so in the marine environment.

10. Ecology -Important ecological roles as saprotrophs, mutualistic symbionts, parasites, or hyperparasites.



                      HABITAT

Fungi exist in various habitats, including deep down in the ocean, lakes, rocks, deserts, very salty environments, and areas of extremely high or low temperatures. Some can prevail even after being exposed to intense UV and cosmic radiation as one would encounter during space travel. During the 13 years the Mir space station was in orbit, a great deal of equipment was continuously being damaged by mutated fungi that had been breeding in the space station. At first technicians were puzzled and thought the problems must have been due to faulty workmanship. The majority of fungi live on land. Fungi and bacteria are the main decomposers of organic matter in virtually all ecosystems on Earth. 

Taxonomists have classified approximately 70,000 types of fungi. Experts say there are many more - possibly 1.5 million. Fungi used to be classified according to their shape, structure, biological and biochemical characteristics. Advances in DNA sequencing have helped extend the classification of different species of fungi. Taxonomy is the classification of organisms.



                       NUTRITION

Although fungi are similar to plants in many ways, they do not have chlorophyll, the green pigment that enables plants to make their own food with the aid of sunlight (photosynthesis).
Fungi release digestive enzymes that decompose things around them, turning them into food. The fungus then absorbs the dissolved foods through Fungi have adapted various ways of doing this: the walls of its cells.  Parasitic fungi - several species of fungi exist as parasites, feeding on live hosts, which might be animals, plants or even other fungi.
 Some of these parasitic fungi damage our crops, sicken farm  animals, and harm or completely destroy trees. Dutch elm disease, caused by the fungus Ophiostoma ulmi destroyed hundreds of millions of elm tress worldwide. The rice blast fungus Magnaporthe oryzae can devastate rice crops. 

 The following fungi can cause serious diseases to humans: aspergilloses, candidoses, coccidioidomycosis, cryptococcosis, histoplasmosis, mycetomas, and paracoccidioidomycosis. An example is vaginal yeast infection.


Saprobes or saprophytes - these break down dead organisms and substances that contain organic compounds and feed on them when they have rotted. Humans welcome saprobes and also fear them. They are useful decomposers of organic material, but also damage wood products and spoil our food. When ships used to be made of wood they were often rendered unusable by wood-digesting saprobes (polypores).

Symbiosis - this is when one living thing builds up a relationship with another for the mutual survival of both. Some fungi form mycorrhizae which enhance a plant-root's capacity to absorb nutrients. 

The plant synthesizes nutrients the fungus needs and exchanges these nutrients for minerals the fungus absorbs from the soil - i.e. the plant and the fungus trade nutrients.  Some leaf-cutting ants eat nothing but a type of fungi that lives in their nests. 
The fungi live on nothing but the leaves the ants carry in for them. If the ant starved the fungi and killed them the ant would have no food and would die; if the fungi found a way of poisoning the ants and killing them off, the fungi would have no food and would die. They both depend on each other for survival.

Saturday, September 2, 2017

MEET THE BEST PRESIDENT AAUA HAS GOT

Name : Olowolafe Bukola
Pka  Comrade Bookey

Department: MICROBIOLOGY

Level πŸ’™ 400 level

Secondary school: Christ Secondary School, Ado Ekiti

Other school: MSC, Ado federal polytechnic, Ado-Ekiti (OND SLT)

State of Origin: Ondo state

Hubby : Travelling and meeting new people

Success :My ability to give back to the society through selfless services

Challenges : Managing both academics and office duties

Future ambition: To be a motivational Speaker

Watchword :You can make it, if u mean it.

Bookey whom was formerly NASS V.P, has been the NAMS president since inception of 2016/17 session, since then, she has shown exceptional abilities in leadership of which numerous other department and faculties are trying to copy.

She became the first female president in the faculty of NASS after winning his opponent in amazing contest showing how her previous services to humanity was well appreciated and proving that she is the one best fitted for the job.

She has singled out as the best president the department has had, the best president the faculty is having presently and the best president in the institution, amazing things a female Comrade does that the male ones can't do.
Her latest achievement was making the department incentives in the first semester, making one of the most beautiful vest in the faculty and AAUA as a whole.

Comrade Bookey initiated series of academic programs which allows students from every level in the department excel in all academic spheres.
For the huge feet of achievement she has attained in just a short time, she has earned a new name (Bookey tΓ³ sure), and fondly praised by his subject...

We love you so such pressy, its your fight that we agreed to finally, no regrets you are our president, sometimes, what a man can do, A WOMAN CALLED BOOKEY CAN DO IT BEST

Friday, September 1, 2017

BACTERIA ENDOSPORES FORMATION


KNOW MORE ALL ABOUT CULTURE MEDIA


ASEPTIC TECHNIQUES IN CULTURE PREPARATION


WOW, MORE MICROORGANISMS IN HUMAN THAN HUMAN CELL

You will never believe it, I never once did, but there are more microbes in human than all the trillions of human cell. The microbe biomes in our body is so so much that we are more microbes than we are human

FUNNY HOW OUR IMMUNE SYSTEM RESPONDS TO BACTERIA INVASION

Interesting clip showing the working modalities of the human immune system, its response to attacks, it balancing pathways..


Watch the cluesπŸ˜‰πŸ˜‰πŸ˜‰πŸ‘

Greatest inoculist!!!
Incubate

DETAILED VIDEO DEMO OF GRAM STAINING AND EXPLANATION

Watch the video that explain in details the gram staining techniques.....

Greatest inoculist!!!
Incubate