Several poisonous chemicals produced by fungi, including Aspergillus flavus and A. parasiticus, are associated with the occurrence of different incidents of animal poisoning. Scientists first stumbled upon these toxins way back in 1960, when as many as 100,000 turkeys in England succumbed to food poisoning after consumption of peanut meals infected by moulds.
Incidentally, all these turkeys were imported from South America and Africa. The poisonous amalgams produced by fungi fragrant chemicals that are exclusively produced by them provided the heat and humidity are suitable.
For example, the most favorable temperature to produce the poisonous substance known as aflatoxin seems to be approximately in the range of 24°C to 28°C, while fungi that develops at temperatures lower than 15°C or at humidity at more than 75 per cent will not be able to manufacture such toxins.
In fact, when experiments were conducted in the laboratories, aflatoxins by fungi was very irregular, and researchers are of the opinion that apart from the temperature and humidity aspects, even other aspects like specific nutrients too establish the production of the toxin.
In fact, aflatoxin has been detected in a number of foods, usually in foods having their origin in agricultural produce, for instance grains, nuts, flour, meat and cheese available in normal atmospheric temperature.
These toxic materials appear to work by attaching to the DNA and encouraging transformations or mutations that subsequently turn out to be deadly or life threatening.
During the course of researches, scientists have discovered that the liver is particularly vulnerable to the poisonous substance called aflatoxin produced by fungi, such as Aspergillus flavus and A. parasiticus. Indirect or incidental proof relates these poisonous substances to diseases caused to humans, but thus far scientists have not been able to establish anything concrete in this regard.
Irrespective of whether the fungi are an eukaryote or a prokaryote, the cytoplasm forms the medium of any of the organism's cell. In fact, the cytoplasm in an eukaryotic cell can be easily differentiated owing to the presence of diverse membranous formations known as organelles.
The best examples of such organelles are mitochondria and chloroplasts that are placed within the cell for carrying out different metabolic and other activities. On the other hand, prokaryotic fungi cells do not possess any organelle.
Instead they enclose several types of particle for providing nourishment to this type of fungi cell. It may be mentioned here that the different chemical activities within the cell (metabolism) as well as digestive activities usually take place in separate vacuoles within the fungi cell.
The cytoplasm of both eukaryotes and prokaryotes encloses ribosomes, even though they are of a different type. In fact, the cytoplasm enclosed by the cell membrane is the place for all types of cellular actions, barring the DNA replication and RNA code transcription. The prokaryotic cells that do not enclose any nucleus, even the DNA replication and the RNA transcription also occurs in the cytoplasm itself.
Fungi species belonging to the genera Epidermophyton, Trichophyton and Microsporum are virtually present everywhere in nature and are responsible for contaminating the skin, hair and nails of the living animals, including their human hosts, and result in severe inflammatory diseases called dermatophytosis.
In layman's terms, this condition is also known as ringworm or tinea owing to their medical manifestation. It is interesting to note that dermatophytosis is generally categorized on the basis of the parts of the body it infects and not according to the species infecting their hosts.
Therefore, the term tinea pedis denotes an infection of the foot, such as athlete's foot, while tinea capitis has an effect on the scalp and tinea unguium denotes the infection of the nail coatings.
It has been found that usually the species belonging to Microsporum have a penchant for infecting hair and nails, while those belonging to Epidermophyton generally contaminate the skin and sometimes also the nails. However, they never infect hair. On the other hand, species belonging to Trichophyton are capable of infecting all the three places - skin, hair and nails, with almost the same ability.
In fact, it has also been found that a lesion may contain more than one species of fungi. Each and every dermatophytes produce several proteolytic enzymes that help them to decompose keratin - the primary protein in the exterior tissues, and thereby, inhabit the host.
Usually, the compounds produced and secreted by the sweat glands slow down the action of these microorganisms, but they eventually overcome this opposition by infecting the hosts in abated conditions as well as in places where the presence of sweat glands is poor.
When such an infection takes place, the initial reactions are owing to inflammatory responses that result in the development of erythematous (redness of the skin caused by dilatation and congestion of the capillaries), flaking or vesicular lesions at the place of the contamination.
Eukaryotes are living beings that have cells possessing a nucleus - a particular compartment bound by a cell membrane accommodating the organism's DNA substances, i.e., genes, discretely from the remaining part of the cellular medium called the cytoplasm.
It is possible to differentiate the nucleus as well as the cytoplasm of eukaryotic cells under a simple light microscope using discriminating colorants. Apart from the nucleus, the eukaryotic cells also enclose particular structures or diminutive organs within the cell membrane that are called organelles that are responsible for carrying out different functions that are necessary for the cell to remain alive.
The primary functions of these organelles include respiration, metabolism and synthesis. The world of eukaryotic cells comprise a large assortment of organisms, including single celled microbes like yeasts and algae and multi-cellular macroscopic beings, such as plants, corals, fish, sponges, birds as well as humans.
Filovirus denotes a family of viruses that comprise agents of specific viral hemorrhagic fever (arbovirus infections, such as dengue, distinguished by fever, chills, malaise and subsequent hemorrhages of capillaries, occasionally resulting in kidney failure and even death).
In fact, filovirus are considered to be recently surfacing disease-bearing microorganisms that have acquired importance only during the past few years. The more familiar members in this virus family include the Marburg and the Ebola viruses.
From the structural point of view, these pathogens appear similar and seem to have long filament-like formations comprising a spiral nucleocapsid (the nucleic acid core and surrounding capsid of a virus) inside a firmly attached lipid covering with viral proteins on the exterior. The filovirus' genetic material or genome is horizontal with a solitary strand of RNA molecule of negative polarization with free ends.
Each filovirus is different from another of the species relating to their respective mechanism to stipulate production of antibodies in the host. When an individual is infected by filovirus it usually results in the development of hemorrhagic fevers with symptoms of severe fevers, debility of muscles, pains and headaches.
Within two to 22 days of being infected by filovirus, the patients experience systemic symptoms like vomiting, diarrhea, pharyngitis or sore throat and a rash that engulfs the entire body.
The hemorrhagic symptoms of the infection become apparent quite quickly, around the third day of the contamination by the virus and the patient experiences petechiae or pinpoint bleeding as well as bleeding all along the gastrointestinal tract.
It may be mentioned here that among all the viruses that cause hemorrhagic fevers, the highest rate of fatality is caused by infections by the Ebola and Marburg viruses. In addition, the symptoms of the hemorrhagic fevers caused by these two deadly viruses are also considered to be the most acute.
While the scientists are yet to develop specific medications or vaccines to combat and cure the life-threatening diseases caused by these viruses, diagnosis of the disease is possible by means of virus isolation or by serological examinations (blood tests undertaken to detect the presence of antibodies against any microorganism). Hence, in such cases the healing is primarily caring.
Scientists are yet to ascertain as to how the humans precisely acquired the Ebola infections. This is primarily owing to the fact that despite several efforts, they are yet to identify the natural host of this virus.
It may be noted here that the first instance of an outbreak of the Marburg virus was linked to the handling of contaminated tissues from a group of African green monkeys exported to Germany. Usually, infection by filovirus takes place by means of close contact, including sexual intercourse, between the infected individual and a healthy person.
Therefore, measure to contain the infection includes diminishing close contacts with people infected by the deadly viruses. Significant precautionary measures usually undertaken to prevent any accidental outbreak of the viruses include cautious handling of scientific and laboratory specimens, proper handling as well as discarding of laboratory equipment and substances, especially those in primate laboratories.
Flavivirus are a family of mainly RNA viruses transmitted by arthropods (tick-borne) that are related to human ailments, such as yellow fever, viral encephalitis and dengue.
These diseases are considered to be the most significant ailments plaguing the developing world. Initially, the flavivirus were categorized under the arbo-virus (any group of RNA-containing viruses that are transmitted by blood sucking arthropods) class as the Group B viruses, but later, they were detached and considered as an autonomous family on the basis of genomic characteristics, anti-genicity as well as their reproduction methods.
Presently, this family not only comprises members of the original arbo-virus species, but also specific diseases that are not transmitted by arthropod members, such as the hepatitis C virus and a number of specific veterinary pathogens known as pestiviruses.
Basically, viruses are spherical in appearance and enclosed elements possessing an inner hub composed of a solitary protein bounded by a firmly attached lipid covering obtained from the host.
Speaking in biological terms, the flavivirus genome or a full set of chromosomes having a single strand, positive-sense RNA molecule that is of approximately 11 kilo-bases and when exposed, it has the aptitude to infect other cells on its own. Reproduction of flavivirus takes place in the cytoplasm as it does not possess any nucleus.
The hypha is actually a strand or filament of a multi-cellular fungus. The usual vegetative hyphae are horizontal and may be septate with individual cells or a mass of uninterrupted multi-nucleate substance. Air-borne hyphae normally signify the reproductive parts of a fungus that are also known as spore-bearing fungus.
Segments surrounded by membranes, something that are solely found in eukaryotic cells, have a crucial role to play as they accommodate the entire genetic data that is necessary for a living being in order to survive. The major element of the nucleus is definitely the cellular DNA enclosed in one or more chromosomes based on the type of organism.
Moreover, the nucleus may even possess specific proteins that bind the DNA, such as histones and a variety of nucleic-acid-polymerizing enzymes. In fact, such compartments are actually places for the reproduction of DNA and also for the recording or transcription of the genes into RNA for the duration of the gene expression and synthesis of protein.
Actually, the nuclear membrane is a phosphor-lipid bilayer possessing two different countenances - nuclear and cytoplasmic - enclosing fixed proteins and pores that provide passages for communication between the nucleus and the remaining parts of the cell or cytoplasm. Using a selective strain under a normal light microscope, one may very easily observe the nuclei of a number of cells.
