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

Abstract

SUMMARYBacteria display an abundance of cellular forms and can change shape during their life cycle. Many plausible models regarding the functional significance of cell morphology have emerged. A greater understanding of the genetic programs underpinning morphological variation in diverse bacterial groups, combined with assays of bacteria under conditions that mimic their varied natural environments, from flowing freshwater streams to diverse human body sites, provides new opportunities to probe the functional significance of cell shape. Here we explore shape diversity among bacteria, at the levels of cell geometry, size, and surface appendages (both placement and number), as it relates to survival in diverse environments. Cell shape in most bacteria is determined by the cell wall. A major challenge in this field has been deconvoluting the effects of differences in the chemical properties of the cell wall and the resulting cell shape perturbations on observed fitness changes. Still, such studies have begun to reveal the selective pressures that drive the diverse forms (or cell wall compositions) observed in mammalian pathogens and bacteria more generally, including efficient adherence to biotic and abiotic surfaces, survival under low-nutrient or stressful conditions, evasion of mammalian complement deposition, efficient dispersal through mucous barriers and tissues, and efficient nutrient acquisition.

Staphylococcus aureus Aggregation and Coagulation Mechanisms, and Their Function in Host–Pathogen Interactions

“…As S. aureus possess several mechanisms that prevent complement deposition and activation on its surface (reviewed in (Zipfel and Skerka, 2014)), it is likely that this pathogen is not affected by the potentially increased complement deposition on larger clumps. Second, agglutination of bacteria by host antibodies is essential for efficient pathogen clearance in many diseases (Weiser, 2013; Yang et al, 2016), and when S. aureus is agglutinated by specific antibodies or pulmonary surfactant proteins it has been shown to increase phagocytosis (Hartshorn et al, 1998; Varrone et al, 2014). However, these host-induced agglutinates are relatively small (up to couple dozen cells (Varrone et al, 2014)) and differ in composition from the clumps induced by fibrinogen binding.…”

Biological HRPs in wastewater

“…One way of classifying them is based on shape, and there are three basic shapes (Dusenbery, 2009): (1) spherical: the bacterial shape likes a ball and a single bacterium is a coccus; (2) rod-shaped: these bacteria are called bacilli (singular bacillus) and part of the rod-shaped bacteria are curved, which are called as vibrio; (3) spiral: these bacteria are known as spirilla (singular spirillus), and they are known as spirochetes if their coil is very tight. Furthermore, a small number of other unusual shapes have been described, such as icosahedron, cube, or star-shaped (Fritz et al, 2004;Yang et al, 2016). The shapes and structures of bacteria are often reflected in their names (Table 3.1).…”

The evolution of bacterial shape complexity by a curvature-inducing module

“…Cells come in a variety of shapes that contribute to fitness in diverse environments 1,2,7,8 . In bacteria, cell curvature can influence motility and host colonization 1,3,4 .…”