Limits...
Appraisal of microbial evolution to commensalism and pathogenicity in humans.

Ghosh AR - Clin Med Insights Gastroenterol (2013)

Bottom Line: The human body is host to a number of microbes occurring in various forms of host-microbe associations, such as commensals, mutualists, pathogens and opportunistic symbionts.While this association with microbes in certain cases is beneficial to the host, in many other cases it seems to offer no evident benefit or motive.The present discussion examines this interaction while tracing the origins of this association, and attempts to hypothesize a possible framework of selective pressures that could have lead microbes to inhabit mammalian host systems.

View Article: PubMed Central - PubMed

Affiliation: Centre for Infectious Diseases and Control, Division of Medical Biotechnology, School of Biosciences and Technology, VIT University, India.

ABSTRACT
The human body is host to a number of microbes occurring in various forms of host-microbe associations, such as commensals, mutualists, pathogens and opportunistic symbionts. While this association with microbes in certain cases is beneficial to the host, in many other cases it seems to offer no evident benefit or motive. The emergence and re-emergence of newer varieties of infectious diseases with causative agents being strains that were once living in the human system makes it necessary to study the environment and the dynamics under which this host microbe relationship thrives. The present discussion examines this interaction while tracing the origins of this association, and attempts to hypothesize a possible framework of selective pressures that could have lead microbes to inhabit mammalian host systems.

No MeSH data available.


Related in: MedlinePlus

Sketch showing plausible selective pressure for making an association (commensalism) of E. coli selectively to humans’ gut in competition/comparison to other microbes such as Leptospira spp., Shigella spp., and Staphylococcus spp. as examples.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4020404&req=5

f1-cgast-6-2013-001: Sketch showing plausible selective pressure for making an association (commensalism) of E. coli selectively to humans’ gut in competition/comparison to other microbes such as Leptospira spp., Shigella spp., and Staphylococcus spp. as examples.

Mentions: The changing environment, with a shift from anaerobic to aerobic atmospheres during the early times of earth’s history, could have possibly provided the selection pressure that made the primarily anaerobic microbes adopt to either an aerobic life (resulting from which we find free living facultative aerobes today) or enter newer habitats providing anaerobic growth conditions. The human body, with anaerobic anatomic niches, could have thus provided the microbes with an ideal growth environment for these microbes to settle in and counter the selection pressure (Fig. 1).17 Better food availability, feeding mobility, increased mobility, and protection from predators and disturbances are possibly the driving forces behind the establishment of commensal and symbiotic relationships in nature16,18 and the microbes could have followed a similar path into the human body.


Appraisal of microbial evolution to commensalism and pathogenicity in humans.

Ghosh AR - Clin Med Insights Gastroenterol (2013)

Sketch showing plausible selective pressure for making an association (commensalism) of E. coli selectively to humans’ gut in competition/comparison to other microbes such as Leptospira spp., Shigella spp., and Staphylococcus spp. as examples.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4020404&req=5

f1-cgast-6-2013-001: Sketch showing plausible selective pressure for making an association (commensalism) of E. coli selectively to humans’ gut in competition/comparison to other microbes such as Leptospira spp., Shigella spp., and Staphylococcus spp. as examples.
Mentions: The changing environment, with a shift from anaerobic to aerobic atmospheres during the early times of earth’s history, could have possibly provided the selection pressure that made the primarily anaerobic microbes adopt to either an aerobic life (resulting from which we find free living facultative aerobes today) or enter newer habitats providing anaerobic growth conditions. The human body, with anaerobic anatomic niches, could have thus provided the microbes with an ideal growth environment for these microbes to settle in and counter the selection pressure (Fig. 1).17 Better food availability, feeding mobility, increased mobility, and protection from predators and disturbances are possibly the driving forces behind the establishment of commensal and symbiotic relationships in nature16,18 and the microbes could have followed a similar path into the human body.

Bottom Line: The human body is host to a number of microbes occurring in various forms of host-microbe associations, such as commensals, mutualists, pathogens and opportunistic symbionts.While this association with microbes in certain cases is beneficial to the host, in many other cases it seems to offer no evident benefit or motive.The present discussion examines this interaction while tracing the origins of this association, and attempts to hypothesize a possible framework of selective pressures that could have lead microbes to inhabit mammalian host systems.

View Article: PubMed Central - PubMed

Affiliation: Centre for Infectious Diseases and Control, Division of Medical Biotechnology, School of Biosciences and Technology, VIT University, India.

ABSTRACT
The human body is host to a number of microbes occurring in various forms of host-microbe associations, such as commensals, mutualists, pathogens and opportunistic symbionts. While this association with microbes in certain cases is beneficial to the host, in many other cases it seems to offer no evident benefit or motive. The emergence and re-emergence of newer varieties of infectious diseases with causative agents being strains that were once living in the human system makes it necessary to study the environment and the dynamics under which this host microbe relationship thrives. The present discussion examines this interaction while tracing the origins of this association, and attempts to hypothesize a possible framework of selective pressures that could have lead microbes to inhabit mammalian host systems.

No MeSH data available.


Related in: MedlinePlus