R. V. Shalini, and Dr. K. Amutha
ABSTRACT: Soil was collected, serially diluted and pure culture obtained; slant was prepared in potato dextrose agar and maintained throughout the study. Morphological, microscopical and macroscopically identification were carried out on the isolated organism. DNA was isolated from the 24 hour culture, for ITS-PCR amplification. DNA was amplified by mixing the template DNA (50nm) with the polymerase reaction buffer, dNTP mix, primers and Taq. Polymerase chain reaction (PCR) was performed in a total volume of 50µL reaction mixture. The PCR product was mixed with loading buffer (8µL) containing 0.025% bromophenol blue, 40% w/v sucrose in water and then loaded in 2% agarose gel with 0.1% of ethidium bromide and the amplified product was visualized under a UV trans illuminator for further examination. The PCR products were finally sequenced using the help of an automated DNA sequencer at progen Ltd (Salem, India) and analyzed with the BLAST program provided by the National Center for Bio-technology information (NCBI) to confirm the fungal species. The current study demonstrates that DNA genome containing 18S rRNA has a high degree of analytical sensitivity and specificity (100%) for the detection of a wide range of fungi.
OBJECTIVE: To isolate, identify and characterize Aspergillus fumigatus using molecular biological methods.
MATERIALS AND METHODS: The soil was collected from different places, pooled together allowed to be dried at room temperature. The morphology based identification of Aspergillus was done which includes the size, shape, colour, ornamentation of spore and mode of attachment. Unfortunately a lot of difficulties arose for phenotypical identification of this fungus due to its unstable characteristics. Comparatively a DNA sequence-based identification format appeared to be the most promising in terms of its speed, ease, objectivity and reliability for species identification.
RESULTS: The preliminary morphology based studies showed the isolated fungi as a species of aspergillus.However after the DNA isolation followed by sequencing it was concluded that the particular species identified as Aspergillus was Aspergillus fumigatus.
KEY WORDS: Aspergillus, serial dilution, DNA, Sequenced.
The presence of organic matter in the soil affects the quantity and quality of microbes in the soil. The development of micro fungi in the soil is favoured by soils having acidic reaction and aerobic condition which is likely present in the soil. However the amount of degradation in the soil is brought about by the organisms present in the soil. 1The rate at which the organic matter is decomposed is inter related with soil microbes. (Arunachalam et al., 1997). Microorganisms come in various sizes and shapes and is determined by the soil ph., temperature, available moisture, degree of aeration, availability of nutrients in the soil etc. The genus of spore forming fungi is found worldwide out of which Aspergillus is the most dominant species and is ubiquitoes.Out of that 95% is occupied by Aspergillus fumigatus. The other pathogenic forms of Aspergillus species are Aspergillus flavus, Aspergillus niger, Aspergillus nidulans, Aspergillus terreus etc. This fungi exists only in mycelial form, and is thermo tolerant capable of growing at temperatures between 15-53°c.Being a spore producing fungi the spores gets dispersed by wind in the atmosphere.
2Aspergillus fumigatus is the most common among all the airborne saprophytic fungal pathogens in immune compromised patients mostly in developed countries (Latge, 1999). It is the main pathogenic agent of various diseases caused in humans including invasive pulmonary aspergillosis, aspergilloma and allergic bronchopulmonary aspergillosis (Tomee
Homeostasis, Co-ordination and Control and Excretory System
Homeostasis is a term translated from the words Homeo meaning ‘’same’’ and stasis meaning ‘‘standing still’’. This term simply describe a dynamic state of equilibrium and the ability of the body to maintain a stable internal condition with a changing outside environment. This process is used to maintain and regulate body temperature, blood sugar level, blood pressure, endocrine system, excretory system and by counteracting the effect of any abnormal level of these factors. Three main components are responsible for the equilibrium process. The receptor which receives information, control centre, receives input from the receptor and the effector, adjusts the factor to a desirable response.
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The normal temperature of the body is around 37°C. To keep the body at this temperature, the amount of heat generated by the body must balance the amount of heat loss. Body temperature is regulated the hypothalamus in the brain – also known as the processing centre. Any changes in the temperature get detected by the temperature receptors in the skin and blood around the effector (e.g. sweat gland and muscles) to bring the body temperature to normal.
In hot conditions, temperature, the sweat gland produces sweat, this cools the body as it evaporates. The skin dilates (vasodilation) allowing blood to flow through the skin capillaries therefore increasing energy loss. The hair on the skin flattens. Also in cold condition, the body responds by causing muscles to constrict (causing shivering) the capillaries of the skin constrict (vasoconstriction) restricting the blood flow through the skin. The hair on the skin stands up to trap more warm hair. The mechanism is show in Figure 1 below.
Endotherms (e.g. mammals and birds) can maintain constant body temperature because they have internal insulation that generates their own heat internally. An advantage of this is that they can survive over a wide range of environment and the disadvantage is that they require more food for energy. Ectotherms (all animals except endotherms) do not have thermal insulation to generate internal body heat; they rely on the environment for a heat source. An advantage is that they use less energy and a disadvantage is that they can only be active at certain times of the day (night).
It is important that the homeostatic mechanism is kept at equilibrium as a failure may result to rise in body temperature above normal (hyperthermia) due to prolong exposure to high temperature or a decrease in the body temperature below normal (hypothermia) due to prolong exposure to low temperature leading to enzymes and cells not able to function at optimum condition, failure of organs and possible death of organism.
Figure 1: Negative feedback regulation of temperature.