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Polystichum recavum (subg. Haplopolystichum; Dryopteridaceae), a new cave fern from Guangxi, China
No full textA new species of Polystichum (subg. Haplopolystichum; Dryopteridaceae), P. recavum, is described from a limestone cave from southern Guangxi, China. Polystichum recavum is most similar to P. cavernicola in having oblanceolate lamina and oblong pinnae, but distinguishable from the latter in number of sterile pinna pairs, shape of pinna apex, and shape of the auricles
Performance and microbial community of a novel non-aeration-based up-flow bioelectrochemical filter (UBEF) treating real domestic wastewater
No full textDomestic wastewater treatment process via the activated sludge is complicated, energy-negative and potentially harmful. In this study, an up-flow bioelectrochemical filter reactor (UBEF) was designed without positive aeration in-priority for treating real domestic wastewater under different hydraulic retention times (HRTs). The removal of chemical oxygen demand (COD), ammonia and total nitrogen was attained at a high efficiency of 89%, 99% and 99% respectively, when HRT was set at h1 of similar to 2.53 d. However, with the decreased of HRT from 2.53 to 0.28 d, the removal efficiency of nitrogen and COD decreased to 50% and 40% respectively, but the maximum power density increased from 3.01 to 98.90 mW/m(3) with a low Coulombic efficiency of 0.25-1.51%. The results demonstrated that the UBEF can remove COD and ammonia from real domestic wastewater in an aeration-free energy sustainable process, although its power output was low. Moreover, the functional bacteria were detected using 16S rRNA gene-based pyrosequencing analysis, which showed that the microbial communities were different under varied HRT conditions. The Thauera-dominated consortium was inoculated in order to enhance the removal of pollutants and the generation of electricity from domestic wastewater, it was kept at a relative abundance when continuously feeding the real wastewater. In particular, nitrogen removing bacteria (NRB) including Nitrosomonas, Ignavibacterium, Thiobacillus, Dokdonella, Comamonas, Sterolibacterium and Flavobacterium were enriched on the anode and the cathode of the UBEF, which contributed to nitrogen remova
Comparative genomic investigation of high-elevation adaptation in ectothermic snakes
No full textSeveral previous genomic studies have focused on adaptation to high elevations, but these investigations have been largely limited to endotherms. Snakes of the genus Thermophis are endemic to the Tibetan plateau and therefore present an opportunity to study high-elevation adaptations in ectotherms. Here, we report the de novo assembly of the genome of a Tibetan hot-spring snake (Thermophis baileyi) and then compare its genome to the genomes of the other two species of Thermophis, as well as to the genomes of two related species of snakes that occur at lower elevations. We identify 308 putative genes that appear to be under positive selection in Thermophis. We also identified genes with shared amino acid replacements in the high-elevation hot-spring snakes compared with snakes and lizards that live at low elevations, including the genes for proteins involved in DNA damage repair (FEN1) and response to hypoxia (EPAS1). Functional assays of the FEN1 alleles reveal that the Thermophis allele is more stable under UV radiation than is the ancestral allele found in low-elevation lizards and snakes. Functional assays of EPAS1 alleles suggest that the Thermophis protein has lower transactivation activity than the low-elevation forms. Our analysis identifies some convergent genetic mechanisms in high-elevation adaptation between endotherms (based on studies of mammals) and ectotherms (based on our studies of Thermophis)
Botany, ethnomedicines, phytochemistry and pharmacology of Himalayan paeony (Paeonia emodi Royle.)
No full textEthnopharmacological relevance: Himalayan paeony (Paeonia emodi Royle.) is an important species used to treat various diseases. This study aimed to compile the detailed traditional medicinal uses, phytochemistry, pharmacology and toxicological investigations on P. emodi. This study also highlights taxonomic validity, quality of experimental designs and shortcomings in previously reported information on Himalayan paeony. Methods: The data was extracted from unpublished theses (Pakistan, China, India and Nepal), and different published research articles confined to pharmacology, phytochemistry and antimicrobial activities using different databases through specific keywords. The relevant information regarding medicinal uses, taxonomic/common names, part used, collection and identification source, authentication, voucher specimen number, plant extracts and their characterization, isolation and identification of phytochemicals, methods of study in silico, in vivo or in vitro, model organism used, dose and duration, minimal active concentration, zone of inhibition (antimicrobial study), bioactive compound(s), mechanism of action on single or multiple targets, and toxicological information. Results: P. emodi is reported for diverse medicinal uses with pharmacological properties like antioxidant, nephroprotective, lipoxygenase inhibitory, cognition and oxidative stress release, cytotoxic, anti-inflammatory, antiepileptic, anticonvulsant, haemaglutination, alpha-chymotrypsin inhibitory, hepatoprotective, hepatic chromes and pharmacokinetics of carbamazepine expression, beta-glucuronidase inhibitory, spasmolytic and spasmogenic, and airway relaxant. Data confined to its taxonomic validity, shows 10% studies with correct taxonomic name while 90% studies with incorrect taxonomic, pharmacopeial and common names. The literature reviewed, shows lack of collection source (11 reports), without proper source of identification (15 reports), 33 studies without voucher specimen number, 26 reports lack information on authentic herbarium submission and most of the studies (90%) without validation of taxonomic names using recognized databases. In reported methods, 67% studies without characterization of extracts, 25% lack proper dose, 40% without duration and 31% reports lack information on proper controls. Similarly, only 18% studies reports active compound(s) responsible for pharmacological activities, 14% studies show minimal active concentration, only 2.5% studies report mechanism of action on target while none of the reports mentioned in silico approach. Conclusion: P. emodi is endemic to Himalayan region (Pakistan, China, India and Nepal) with diverse traditional therapeutic uses. Majority of reviewed studies showed confusion in its taxonomic validity, incomplete methodologies and ambiguous findings. Keeping in view the immense uses of P. emodi in various traditional medicinal systems, holistic pharmacological approaches in combination with reverse pharmacology, system biology, and "omics" technologies are recommended to improve the quality of research which leads to natural drug discovery development at global perspectives
Soybean supplementation increases the resilience of microbial and nematode communities in soil to extreme rainfall in an agroforestry system
No full textA current challenge for ecological research in agriculture is to identify ways in which to improve the resilience of the soil food web to extreme climate events, such as severe rainfall. Plant species composition influence soil biota communities differently, which might affect the recovery of soil food web after extreme rainfall. We compared the effects of rainfall stress up on the soil microbial food web in three planting systems: a monoculture of the focal species Zanthoxylum bungeanum and mixed cultures of Z. bungeanum and Medicago sativa or Z. bungeanum and Glycine max. We tested the effect of the presence of a legume on the recovery of trophic interactions between microorganisms and nematodes after extreme rainfall. Our results indicated that all chemical properties of the soil recovered to control levels (normal rainfall) in the three planting systems 45 days after exposure to extreme rain. However, on day 45, the bulk microbial community differed from controls in the monoculture treatment, but not in the two mixed planting treatments. The nematode community did not fully recover in the monoculture or Z. bungeanum and M. sativa treatments, while nematode populations in the combined Z. bungeanum and G. max treatment were indistinguishable from controls. G. max performed better than M. sativa in terms of increasing the resilience of microbial and nematode communities to extreme rainfall. Soil microbial biomass and nematode density were positively correlated with the available carbon and nitrogen content in soil, demonstrating a link between soil health and biological properties. This study demonstrated that certain leguminous plants can stabilize the soil food web via interactions with soil biota communities after extreme rainfall. (C) 2018 Elsevier B.V. All rights reserved
Solution scattering study of the Bacillus subtilis PgdS enzyme involved in poly-gamma-glutamic acids degradation
No full textThe PgdS enzyme is a poly-gamma-glutamic (gamma-PGA) hydrolase, which has potential application for a controllable degradation of gamma-PGA by enzymatic depolymerization; however, the structure of PgdS is still unknown. Here, to study in detail the full-length PgdS structure, we analyze the low-resolution architecture of PgdS hydrolase from Bacillus subtilis in solution using small angle X-ray scattering (SAXS) method. Combining with other methods, like dynamic light scattering and mutagenesis analyses, a model for the full length structure and the possible substrate delivery route of PgdS are proposed. The results will provide useful hints for future investigations into the mechanisms of gamma-PGA degradation by the PgdS hydrolase and may provide valuable practical information
Inferring ecological explanations for biogeographic boundaries of parapatric Asian mountain frogs
No full textBackground: Identifying and understanding the mechanisms that shape barriers to dispersal and resulting bio-geographic boundaries has been a longstanding, yet challenging, goal in ecology, evolution and biogeography. Characterized by stable, adjacent ranges, without any intervening physical barriers, and limited, if any, range overlap in a narrow contact zone, parapatric species are an interesting system for studying biogeographic boundaries. The geographic ranges of two parapatric frog species, Feirana quadranus and F. taihangnica, meet in a contact zone within the Qinling Mountains, an important watershed for East Asia. To identify possible ecological determinants of the parapatric range boundaries for two closely related frog species, we quantified the extent of their niche differentiation in both geographical and environmental space combining ecological niche models with an ordination technique. We tested two alternative null hypotheses (sharp environmental gradients versus a ribbon of unsuitable habitat dividing two highly suitable regions) for biogeographic boundaries, against the null expectation that environmental variation across a given boundary is no greater than expected by chance. Results: We found that the niches of these two parapatric species are more similar than expected by chance, but not equivalent. No sharp environmental gradient was found, while a ribbon of unsuitable habitat did act as a barrier for F. quadranus, but not for F. taihangnica. Conclusions: Integrating our findings with historical biogeographic information, our results suggest that at a contact zone, environmental tolerance restricted F. quadranus from dispersing further north, while interspecific competition most likely prevented the southward expansion of F. taihangnica. This study highlights the importance of both climate and competition in exploring ecological explanations for parapatric range boundaries between ecologically similar frog species, in particular under the effects of changing climate
Thinning increased fine root production, biomass, turnover rate and understory vegetation yield in a Chinese fir plantation
No full textQuantifying the fine root (FR) dynamics of understory plants and canopy trees is essential to accurately assess the impact of forest operations on forest production and ecological stability. However, such information has been poorly quantified, and little is known about the underlying mechanism of FR dynamics in response to human disturbances such as thinning. We investigated the FR dynamics and the understory vegetation of a Chinese fir plantation in southern China under four levels of thinning intensity (30, 50 and 70% of trees removed and uncut controls). We found that the total FR biomass, production and mortality, and turnover linearly increased with thinning intensity, and the FRs were stimulated more in the deeper soil layer (10-20 cm) than in the surface soil layer (0-10 cm). Across all stands, understory plants contributed 35-42% and 34-49% to the total biomass and production, respectively. The biomass and species richness of the understory plants increased with increasing thinning intensity. The principal component analysis indicated that the increased FR production and turnover rate of Chinese fir mainly result from increased understory plant richness and diversity, whereas the increased FR production and turnover rate in understory vegetation result from warmer soil and lower soil phosphorus (P). Our findings provide evidence for the positive effects of thinning on FR dynamics. The results suggest that the FR dynamics of understory plants could play a more critical role than expected in determining forest carbon (C) and nutrient cycling. The mechanism affecting FR dynamics following thinning differed between the understory plants and the canopy trees
Investigating the Effectiveness of Road-related Mitigation Measures under Semi-controlled Conditions: A Case Study on Asian Amphibians
Full text linkRoad traffic is the main factor causing the decline in amphibian populations worldwide. The proper design of an amphibian tunnel is one of the most efficient measures to mitigate the negative impacts of road traffic on amphibians. However, no study has investigated the effectiveness of amphibian tunnels under semi-controlled conditions in Asian amphibians. Here, we selected two representative amphibian species, the Chinese brown frog, Rana chensinensis, and the Asiatic toad, Bufo gargarizans, which suffer the most severe road mortality along the roads in Northeast China. We placed experimental arrays of culverts of various sizes (diameters of 1.5, 1, and 0.5 m for circular culverts; side lengths of 1.5, 1, and 0.5 m for box culverts), and substrate type (soil, concrete, and metal) to examine the preferences of both species during the migratory season between May and September in 2016 and 2017. The results revealed that the Chinese brown frog preferred mid- and large-sized culverts as well as soil culverts. We concluded that culverts with a side length ≥ 1 m, lined with soil, and accompanied by a ≥ 0.4 m high guide drift fence and ≤ 45° gradient on the roadside ditch wall would best facilitate road crossings for both species and likely for other amphibian species in Northeast China
Specific legumes allay drought effects on soil microbial food web activities of the focal species in agroecosystem
No full textBackground and aimsThe incidence of extreme weather events, particularly drought is predicted to increase in the future and alter the ecosystem process. Despite that the interplay between plant species play a critical role in reducing the vulnerability of soil ecosystem to drought, whether the presence of legumes in plant community could maintain nutrient uptake of focal species by stabilizing soil biota and ecosystem processes under drought conditions remains essentially unexplored.MethodsIn a field experiment, the soil biota community and ecosystem processes were studied using four planting systems contain monoculture of focal species Zanthoxylum bungeanum, mixed cultures of Z. bungeanum and Capsicum annuum, Z. bungeanum and Medicago sativa, and Z. bungeanum and Glycine max subjected to drought.ResultsDrought had no significant effects on soil microbial biomass in monoculture and mixed cultures, but significantly increased microbial stress indices. Drought significantly increased the densities of total nematodes, herbivores, bacterivores and fungivores in Z. bungeanum and M. sativa mixed culture, but significantly decreased the total nematodes, bacterivores and fungivores in Z. bungeanum and G. max mixed culture. Under drought stress, leaf nitrogen concentrations of Z. bungeanum were significantly higher in Z. bungeanum and M. sativa mixed culture than Z. bungeanum monoculture and the other mixed cultures, this is mainly due to higher microbial activity and net nitrogen mineralization rate.ConclusionDifferences in resistance traits of neighbors had additive effects and rapidly reflected in different soil ecosystem processes and nutrient uptake of focal species. Our results revealed that specific legume species intercropping management could stabilize focal species by maintaining soil ecosystem processes under drought condition