Networks of lexical borrowing and lateral gene transfer in language and genome evolution

Like biological species, languages change over time. As noted by Darwin, there are many parallels between language evolution and biological evolution. Insights into these parallels have also undergone change in the past 150 years. Just like genes, words change over time, and language evolution can be likened to genome evolution accordingly, but what kind of evolution? There are fundamental differences between eukaryotic and prokaryotic evolution. In the former, natural variation entails the gradual accumulation of minor mutations in alleles. In the latter, lateral gene transfer is an integral mechanism of natural variation. The study of language evolution using biological methods has attracted much interest of late, most approaches focusing on language tree construction. These approaches may underestimate the important role that borrowing plays in language evolution. Network approaches that were originally designed to study lateral gene transfer may provide more realistic insights into the complexities of language evolution

Thiol stabilized copper nanoparticles exert antimicrobial properties by preventing cell division in Escherichia coli

151-157The uses of metallic nanoparticles have gained importance as one of the therapeutic options to treat infections. Here, we synthesized stable copper nanoparticles (CuNPs) using Thiosalicylic acid and assessed their antimicrobial activities against various Gram-negative bacteria. The synthesized CuNPs had absorption maxima of 570 nM with a size range of 5-11 nM and face-centred cubic (Fcc) crystal structure. The bacterial cells in their planktonic and sessile forms were susceptible to CuNPs. The nanoparticles did not show any cytotoxicity to murine macrophages (RAW264.7) below 60 µg/mL. However, the expression of oxidative stress defence gene ahpC revealed the possibility of ROS generation upon treatment with CuNPs. Interestingly, the cell division proteins like, FtsZ and FtsI were destabilized in the presence of CuNPs which in turn inhibited bacterial cell division. In conclusion, it may be stated that the synthesized CuNPs can kill bacteria by arresting cell division and/or by ROS generation

Thiol stabilized copper nanoparticles exert antimicrobial properties by preventing cell division in Escherichia coli

The uses of metallic nanoparticles have gained importance as one of the therapeutic options to treat infections. Here, we synthesized stable copper nanoparticles (CuNPs) using Thiosalicylic acid and assessed their antimicrobial activities against various Gram-negative bacteria. The synthesized CuNPs had absorption maxima of 570 nM with a size range of 5-11 nM and face-centred cubic (Fcc) crystal structure. The bacterial cells in their planktonic and sessile forms were susceptible to CuNPs. The nanoparticles did not show any cytotoxicity to murine macrophages (RAW264.7) below 60 µg/mL. However, the expression of oxidative stress defence gene ahpC revealed the possibility of ROS generation upon treatment with CuNPs. Interestingly, the cell division proteins like, FtsZ and FtsI were destabilized in the presence of CuNPs which in turn inhibited bacterial cell division. In conclusion, it may be stated that the synthesized CuNPs can kill bacteria by arresting cell division and/or by ROS generation

Adaptation to life on land at high O-2 via transition from ferredoxin-to NADH-dependent redox balance

Pyruvate : ferredoxin oxidoreductase (PFO) and iron only hydrogenase ([Fe]-HYD) are common enzymes among eukaryotic microbes that inhabit anaerobic niches. Their function is to maintain redox balance by donating electrons from food oxidation via ferredoxin (Fd) to protons, generating H2 as a waste product. Operating in series, they constitute a soluble electron transport chain of one-electron transfers between FeS clusters. They fulfil the same function—redox balance—served by two electron-transfers in the NADH- and O2-dependent respiratory chains of mitochondria. Although they possess O2-sensitive FeS clusters, PFO, Fd and [Fe]-HYD are also present among numerous algae that produce O2. The evolutionary persistence of these enzymes among eukaryotic aerobes is traditionally explained as adaptation to facultative anaerobic growth. Here, we show that algae express enzymes of anaerobic energy metabolism at ambient O2 levels (21% v/v), Chlamydomonas reinhardtii expresses them with diurnal regulation. High O2 environments arose on Earth only approximately 450 million years ago. Gene presence/absence and gene expression data indicate that during the transition to high O2 environments and terrestrialization, diverse algal lineages retained enzymes of Fd-dependent one-electron-based redox balance, while the land plant and land animal lineages underwent irreversible specialization to redox balance involving the O2-insensitive two-electron carrier NADH

Discovery of anaerobic lithoheterotrophic haloarchaea, ubiquitous in hypersaline habitats

Hypersaline anoxic habitats harbour numerous novel uncultured archaea whose metabolic and ecological roles remain to be elucidated. Until recently, it was believed that energy generation via dissimilatory reduction of sulfur compounds is not functional at salt saturation conditions. Recent discovery of the strictly anaerobic acetotrophic Halanaeroarchaeum compels to change both this assumption and the traditional view on haloarchaea as aerobic heterotrophs. Here we report on isolation and characterization of a novel group of strictly anaerobic lithoheterotrophic haloarchaea, which we propose to classify as a new genus Halodesulfurarchaeum. Members of this previously unknown physiological group are capable of utilising formate or hydrogen as electron donors and elemental sulfur, thiosulfate or dimethylsulfoxide as electron acceptors. Using genome-wide proteomic analysis we have detected the full set of enzymes required for anaerobic respiration and analysed their substrate-specific expression. Such advanced metabolic plasticity and type of respiration, never seen before in haloarchaea, empower the wide distribution of Halodesulfurarchaeum in hypersaline inland lakes, solar salterns, lagoons and deep submarine anoxic brines. The discovery of this novel functional group of sulfur-respiring haloarchaea strengthens the evidence of their possible role in biogeochemical sulfur cycling linked to the terminal anaerobic carbon mineralisation in so far overlooked hypersaline anoxic habitats.</p

Divergent functional isoforms drive niche specialisation for nutrient acquisition and use in rumen microbiome

Many microbes in complex competitive environments share genes for acquiring and utilising nutrients, questioning whether niche specialisation exists and if so, how it is maintained. We investigated the genomic signatures of niche specialisation in the rumen microbiome, a highly competitive, anaerobic environment, with limited nutrient availability determined by the biomass consumed by the host. We generated individual metagenomic libraries from 14 cows fed an ad libitum diet of grass silage and calculated functional isoform diversity for each microbial gene identified. The animal replicates were used to calculate confidence intervals to test for differences in diversity of functional isoforms between microbes that may drive niche specialisation. We identified 153 genes with significant differences in functional isoform diversity between the two most abundant bacterial genera in the rumen (Prevotella and Clostridium). We found Prevotella possesses a more diverse range of isoforms capable of degrading hemicellulose, whereas Clostridium for cellulose. Furthermore, significant differences were observed in key metabolic processes indicating that isoform diversity plays an important role in maintaining their niche specialisation. The methods presented represent a novel approach for untangling complex interactions between microorganisms in natural environments and have resulted in an expanded catalogue of gene targets central to rumen cellulosic biomass degradation