Ancient origins determine global biogeography of hot and cold desert cyanobacteria

Factors governing large-scale spatio-temporal distribution of microorganisms remain unresolved, yet are pivotal to understanding ecosystem value and function. Molecular genetic analyses have focused on the influence of niche and neutral processes in determining spatial patterns without considering the temporal scale. Here, we use temporal phylogenetic analysis calibrated using microfossil data for a globally sampled desert cyanobacterium, Chroococcidiopsis, to investigate spatio-temporal patterns in microbial biogeography and evolution. Multilocus phylogenetic associations were dependent on contemporary climate with no evidence for distance-related patterns. Massively parallel pyrosequencing of environmental samples confirmed that Chroococcidiopsis variants were specific to either hot or cold deserts. Temporally scaled phylogenetic analyses showed no evidence of recent inter-regional gene flow, indicating populations have not shared common ancestry since before the formation of modern continents. These results indicate that global distribution of desert cyanobacteria has not resulted from widespread contemporary dispersal but is an ancient evolutionary legacy. This highlights the importance of considering temporal scales in microbial biogeography

White-Rot Fungi in Bioremediation

Bioremediation is defined as the application of biological processes to the treatment of pollution. Most research on the field of bioremediation has focused on bacteria, and fungal bioremediation (mycoremediation) has also been attracting the interest just for a couple of decades. The toxicity of many pollutants reduces natural attenuation of bacteria, but white-rot fungi (WRF) can challenge with toxic levels of the most pollutants. Fungi are robust organisms having very high tolerance to toxic environments, and this feature makes them ideal to use for bioremedial purposes. White-rot fungi are basidiomycetes that are capable of degrading a lignocellulose substrate. Extracellular enzymes involved in the degradation of lignin and xenobiotics by white-rot fungi include several kinds of laccases, peroxidases, and oxidases producing H2O2. Nowadays, great progress in this area may derive from modern molecular technologies, which may provide cheaper potential sources of various enzymes by means of genetically modified microorganisms or plants. This chapter explains the bioremediation and its application conditions and degradation mechanisms of the harmful compounds such as textile dyes, PAHs, chlorophenols, TNT, pesticides, and nylon