The sulfur formation system mediating extracellular cysteine-cystine recycling in Fervidobacterium islandicum AW-1 is associated with keratin degradation

Most extremophilic anaerobes possess a sulfur formation (Suf) system for Fe–S cluster biogenesis. In addition to its essential role in redox chemistry and stress responses of Fe–S cluster proteins, the Suf system may play an important role in keratin degradation by Fervidobacterium islandicum AW-1. Comparative genomics of the order Thermotogales revealed that the feather-degrading F. islandicum AW-1 has a complete Suf-like machinery (SufCBDSU) that is highly expressed in cells grown on native feathers in the absence of elemental sulfur (S⁰). On the other hand, F. islandicum AW-1 exhibited a significant retardation in the Suf system-mediated keratin degradation in the presence of S⁰. Detailed differential expression analysis of sulfur assimilation machineries unveiled the mechanism by which an efficient sulfur delivery from persulfurated SufS to SufU is achieved during keratinolysis under sulfur starvation. Indeed, addition of SufS–SufU to cell extracts containing keratinolytic proteases accelerated keratin decomposition in vitro under reducing conditions. Remarkably, mass spectrometric analysis of extracellular and intracellular levels of amino acids suggested that redox homeostasis within cells coupled to extracellular cysteine and cystine recycling might be a prerequisite for keratinolysis. Taken together, these results suggest that the Suf-like machinery including the SufS–SufU complex may contribute to sulfur availability for an extracellular reducing environment as well as intracellular redox homeostasis through cysteine released from keratin hydrolysate under starvation conditions.     

The role of mendelian genetics in stragetic models on animal behaviour

The authors combine known models for the evolution of (a) strategies in animal conflicts, and (b) gene frequencies for differential fecundity in order to relate the sociobiological notion of evolutionarily stable strategy with the genetic mechanism of Mendelian populations.     

Burden of depression and anxiety among leprosy affected and associated factors—A cross sectional study from India

BackgroundLeprosy is a Neglected Tropical Diseases (NTDs) known to cause stigma and discrimination in low-and middle-income countries. It often results in visible impairments, thus pre-disposing to poor mental health. Aim of the study was to estimate the prevalence of depression and anxiety among people affected by Leprosy and to determine the associated factors.Methodology/Principal findingsA multi-centric, cross-sectional study was carried out in four leprosy endemic states of India—Chhattisgarh, Maharashtra, West Bengal and Tamil Nadu in randomly selected blocks (a sub-unit of district), from one district in each state. From selected blocks those registered for leprosy treatment at public health or referral centres, people above the age of 18 years were interviewed with PHQ-9 and GAD-7 questionnaires for Depression and Anxiety, respectively. Disease profile like leprosy classification, deformity grade, number and site of the patches and socio-economic status were collected along with individual data.Of the total 220 respondents, prevalence of depression and anxiety symptoms was, 33% (73) and 19% (42), respectively. Presence of disability (47%) and Female gender (46%) were significantly associated with depression. Presence of disability (32%), Lower income group (27%) and low education (22%) were significantly associated with symptoms of anxiety. As the severity of disability increased, risk of developing depression and anxiety increased.ConclusionThe study indicates that more than 30% of people affected by leprosy have mental health problems, which emphasizes the importance of mental health care services in leprosy. Women, those who had lower level of education, those belonging to lower socio-economic status and those with any level of disability due to leprosy are at risk of developing depression and/or anxiety. The study concludes more attention to be paid to the categories identified to be at risk.     

Resorption

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