Bacterial differentiation, development, and disease: mechanisms for survival

Abstract

Bacteria have the exquisite ability to maintain a precise diameter, cell length and shape. The dimensions of bacteria size and shape are a classical metric in the distinction of bacterial species. Much of what we know about the particular morphology of any given species is the result of investigations of planktonic cultures. As we explore deeper into the natural habitats of bacteria, it is increasingly clear that bacteria can alter their morphology in response to the environment in which they reside. Specific morphologies are also becoming recognized as advantageous for survival in hostile environments. This is of particular importance in the context of both colonization and infection in the host. There are multiple examples of bacterial pathogens that use morphological changes as a mechanism for evasion of host immune responses and continued persistence. This review will focus on two systems where specific morphological changes are essential for persistence in animal models of human disease. We will also offer insight into the mechanism underlying the morphological changes and how these morphotypes aid in persistence. Additional examples of morphological changes associated with survival will be presented.

Staying in Shape: the Impact of Cell Shape on Bacterial Survival in Diverse Environments

“…As mentioned previously, filamentation of UPEC within these IBCs is due to induction of the SOS response as the cells cope with host immune insults that damage their DNA (98). Eventually, the coccoid UPEC cells become motile and bacillary (late IBCs), lysing the host cell and releasing both filaments and motile rods for further rounds of invasion into neighboring bladder cells (egress and second-generation IBCs) (90). Since each IBC represents a single invasion event, this suggests that the morphological changes observed within these communities are part of a developmental program (90).…”

“…For this review, filaments encompass both single-nucleus and multinucleated cells that can be separated by septa and are connected by a contiguous outer membrane (with or without evidence of outer membrane invagination in Gramnegative bacteria). Interestingly, multiple bacterial pathogens have been reported to undergo filamentation in vivo, suggesting that filamentation may be important for pathogenesis (81,90).…”

“…Eventually, the coccoid UPEC cells become motile and bacillary (late IBCs), lysing the host cell and releasing both filaments and motile rods for further rounds of invasion into neighboring bladder cells (egress and second-generation IBCs) (90). Since each IBC represents a single invasion event, this suggests that the morphological changes observed within these communities are part of a developmental program (90). Each phase and its associated morphotype presumably function to facilitate intracellular growth and subsequent rounds of infection.…”

The predatory life cycle of Myxococcus xanthus

“…The size and shape of individual cells have long been used as a means of distinguishing developmental stages within a species (Justice et al, 2014). Myx.…”

Amplifying renal immunity: the role of antimicrobial peptides in pyelonephritis

“…After internalization, UPEC enter a cytosolic niche called an intracellular bacterial community (IBC). [16][17][18][19] IBCs develop from a single bacterium and consist of an estimated 10 4 -10 5 organisms encased in a highly organized polysaccharide matrix, reminiscent of a bacterial biofilm. As the IBC matures, it engulfs the host nucleus.…”