A built environment is a human‐made environment providing surroundings for human occupancy, activities, and settlement. It is supposed to safeguard humans from all undesirable and harmful pollutants; however, indoor concentrations of some pollutants are much greater than that of the outdoors. Bioaerosols infiltrate from the outdoors in addition to many indoor sources of bioaerosols including the use of various chemicals as well as activities like cooking, smoking, cleaning, or even normal movement. They are also associated with a number of serious health concerns. Various ecological factors associated with the generation, the persistence as well as the dispersal of these microbial components of indoor bioaerosols, are discussed in this review, that have not been considered all together till now. The factors like microbial taxa, environmental factors, and anthropogenic activities (human occupancy, activities, and impact of urbanization) are addressed in the review. Effects of both indoor environmental factors like architectural design, lighting, ventilation, temperature, humidity, indoor/outdoor ratio, particulate matter, indoor chemistry as well as outdoor environmental factors like geography, seasons, and meteorology on the microbial concentrations have been discussed. Efforts are underway to design selective pressures for microbes to create a healthy symbiotic built microbiome as the “right” indoor microbiome is a “healthy” indoor microbiome.
With main purpose of developing a coherent baseline information of timberline forests of Sikkim, Eastern Himalaya, we investigated, (i) forest structure and composition, (ii) regeneration status of dominant timberline tree species between timberline and treeline, (iii) influence of environmental variables in species composition, and (iv) relationship between environmental variables and ecological attributes. The study was conducted along the timberline stretch of Dzongri landscape nested within the Khangchendzonga National Park (UNESCO’s World Heritage Site, 2016), a core zone of Khangchendzonga Biosphere Reserve (in UNESCO WNBRs, 2018), Sikkim, India. We employed quadrat method to sample 9 contiguous sites to capture all possible variations in timberline composition. Transect method was used to study the regeneration of woody taxa between timberline to treeline. In total, 20 woody species belonging to 10 genera and 6 families were recorded. Among these, Abies densa, Rhododendron lanatum and Sorbus microphylla exhibited higher dominance, comprising of 50% of the total importance value index (IVI) weightage. Betula utilis the common treeline species in much of the western and central parts of Himalaya was absent here. Tree density in studied timberline was significantly higher than its western Himalayan counterparts of Indian Himalayan region. Environmental variables viz., elevation, slope, and humus were observed determinants of species composition across the study area. The species dominance correlated negatively (p<0.01; n = 9) with species diversity and richness. We observed an irregular spatial pattern of timberline across the 9 study sites, and the extent of timberline elements (seedling; sapling; live tree or dead tree) ranged between 5.3m to 187.7m higher than the current timberline at different sites. The present trends suggest that upslope advancement is unlikely to occur in near future, while treeline densification is anticipated. Further investigations are suggested to develop a holistic understating of these timberline patterns across the Indian Himalayan region.
The soil sampled at different growth stages along the cropping period of cotton were analyzed using various molecular tools: restriction fragment length polymorphism (RFLP), terminal restriction length polymorphism (T-RFLP), and cloning-sequencing. The cluster analysis of the diazotrophic community structure of early sampled soil (0, 15, and 30 days) was found to be more closely related to each other than the later sampled one. Phylogenetic and diversity analysis of sequences obtained from the first (0 Day; C0) and last soil sample (180 day; C180) confirmed the data. The phylogenetic analysis revealed that C0 was having more unique sequences than C180 (presence of γ-Proteobacteria exclusively in C0). A relatively higher richness of diazotrophic community sequences was observed in C0 (S(ACE) : 30.76; S(Chao1) : 20.94) than C180 (S(ACE) : 18.00; S(Chao1) : 18.00) while the evenness component of Shannon diversity index increased from C0 (0.97) to C180 (1.15). The impact of routine agricultural activities was more evident based on diazotrophic activity (measured by acetylene reduction assay) than its structure and diversity. The nitrogenase activity of C0 (1264.85 ± 35.7 ηmol of ethylene production g(-1) dry soil h(-1) ) was statistically higher when compared to all other values (p < 0.05). There was no correlation found between diazotrophic community structure/diversity and N2 fixation rates. Thus, considerable functional redundancy of nifH was concluded to be existing at the experimental site.
We have already entered the post-antibiotic era as the outbreaks of numerous multidrug-resistant strains in the community as well as hospital-acquired infections are ringing alarm bells in the health sector. Acinetobacter baumannii is one such pathogen that has been considered a worldwide threat as it acquires multidrug resistance. It is one of the most challenging hospitalacquired pathogens as World Health Organization has listed carbapenem-resistant A. baumannii as a critical priority pathogen with limited therapeutic options.There is an urgent need to develop novel strategies against such pathogens to tackle the global crisis. Bacteriophages (phages), especially the lytic ones have re-emerged as a potential therapeutic approach. This review encompasses vast majority of phages against A. baumannii strains with special references related to single phage or monophage therapy, use of phage cocktails, combination therapy with antibiotics, use of phage-derived enzymes like endolysins and depolymerases to combat the pathogen and explore their therapeutic aspects. The concurrent ecological as well as evolutionary interplay between the phages and host bacteria demands in depthresearch and knowledge, so as to utilize the maximum potential of the bacteriophage therapy.
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