In: Biology
Identify two strategies that some bacteria may utilize to survive extreme or less than optimal environments.
Extremophiles are organisms able to survive in prohibitive
conditions from the physical and chemical point of view, where most
of the living organisms on Earth would survive with great
difficulty or perish
They are classified according to the conditions in which they grow:
As thermophiles and hyperthermophiles (organisms growing at high or
very high temperatures, respectively), psychrophiles (organisms
that grow best at low temperatures), acidophiles and alkaliphiles
(organisms optimally adapted to acidic or basic pH values,
respectively), barophiles (organisms that grow best under
pressure), and halophiles (organisms that require NaCl for growth).
In addition, these organisms are normally polyextremophiles, being
adapted to live in habitats where various physicochemical
parameters reach extreme values. For example, many hot springs are
acid or alkaline at the same time, and usually rich in metal
content; the deep ocean is generally cold, oligotrophic (very low
nutrient content), and exposed to high pressure; and several
hypersaline lakes are very alkaline.
Alternative survival straighty
Chemotactic behaviors, i.e. moving toward attractants and away from repellents, are apparently an effective set of survival strategies in heterogeneous environments. For some bacteria, migration towards the rhizosphere of plants is the most promising way to obtain organic nutrients in soils; tomato root colonization of a plant growth-promoting rhizobacterium, Pseudomonas fluorescens .However, future research should clarify whether or not if the speed and distances traveled via bacterial cellular motility are practical such that cells can advantageously reach roots in soil environments.
Programmed cell death in bacteria has also been proposed as a possible strategy for preserving some of the population from stresses through utilization of the nutrients derived from the dead cells .The effectiveness of such programmed cell death in bacteria as a survival strategy is however a highly controversial issue in microbial ecology.