Evolution in the Bacillaceae

Abstract

The family Bacillaceae constitutes a phenotypically diverse and globally ubiquitous assemblage of bacteria. Investigation into how evolution has shaped, and continues to shape, this family has relied on several widely ranging approaches from classical taxonomy, ecological field studies, and evolution in soil microcosms to genomic-scale phylogenetics, laboratory, and directed evolution experiments. One unifying characteristic of the Bacillaceae, the endospore, poses unique challenges to answering questions regarding both the calculation of evolutionary rates and claims of extreme longevity in ancient environmental samples.

Experimental evolution of Bacillus subtilis

“…Evolved phenotypes References Domestication Loss of biofilm and fruiting body formation, swarming motility and prophage content; increased competence (Fajardo-Cavazos et al, 2016;Myagmarjav et al, 2016) Soil microcosm Increased population density (Graham and Istock, 1979) Stringent sporulation Decreased lag-time, increased growth rate, loss of superfluous biosynthetic pathways (Maughan and Nicholson, 2004;Maughan et al, 2006;2009;Brown et al, 2011;Maughan and Nicholson, 2011;2012) …”

“…Everest to 105.5 kPa at the Dead Sea. The atmospheric pressure on Mars is more than 100-fold lower than Earth's, averaging 0.7 kPa and ranging from 0.1 kPa at the top of Olympus Mons to 1 kPa at the bottom of Hellas Basin (Fajardo-Cavazos et al, 2016). Growth of B. subtilis is inhibited at pressures below 2.5 kPa, 2-3 times above the highest pressure on the surface of Mars (Schuerger and Nicholson, 2006).…”

“…They have been isolated everywhere from the upper layers of the atmosphere to the depths of ocean trenches, and from almost every conceivable environment in between (Fajardo-Cavazos et al, 2014;Zeigler and Perkins, 2015). Members include not only mesophiles, but acidophiles (Ciuffreda et al, 2015), alikaliphiles (Preiss et al, 2015), halophiles (Hanelt and Muller, 2013), psychrophiles (Larkin and Stokes, 1966), thermophiles (Zeigler, 2014;Hussein et al, 2015) and UV-radiation tolerant organisms (Ordonez et al, 2009).…”

Ecology of Bacillaceae

“…Lifestyles (and thus ecological behavior) of all members of the Bacillaceae are tightly defined by their ability to form endospores. Spores allow survival under adverse conditions for shorter or longer time periods, even up to thousands of years (30) (see Fajardo-Cavazos et al [233] for additional details on the isolation of ancient spores). The formation of endospores in some Bacillus species can be induced by nutrient deprivation and high cell population densities, and is also affected by environmental factors such as changes in pH, water content, or temperature (31).…”

Papel biológico do gene "yba"B codificador de uma proteína associada ao nucleóide sobre a regulação gênica global de "Salmonella enterica" Typhimurium

“…Curiosamente, em nosso estudo, vimos que RecR está sob seleção positiva em Firmicutes, um padrão que também é exibido por YbaB. Considerando que recR é um dos genes mais conservados em procariotos (ROCHA; CORNET; MICHEL, 2005), a variabilidade observada em Firmicutes merece mais estudos.Além das particularidades apresentadas pelo sistema de recombinação homóloga em Firmicutes, esse filo obteve sucesso na conquista da maioria dos nichos, especialmente a família Bacillaceae, cujos microrganismos podem formar endósporo, estrutura que proporciona alto grau de resistência à estresses ambientais (FAJARDO-CAVAZOS, P. MAUGHAN;NICHOLSON, 2014). Além da família Bacillaceae, espécies do gênero Clostridium sp.…”