A phylogenetic approach identifies patterns of beta diversity and floristic subregions of the Qinghai-Tibet Plateau.

Patterns of taxonomic and phylogenetic beta diversity and their relationships with environmental correlates can help reveal the origin and evolutionary history of regional biota. The Qinghai-Tibet Plateau (QTP) harbors an exceptionally diverse flora, however, a phylogenetic perspective has rarely been used to investigate its beta diversity and floristic regions. In this study, we used a phylogenetic approach to identify patterns of beta diversity and quantitatively delimit floristic regions on the Qinghai-Tibet Plateau. We also examined the relationships between multifaceted beta diversity, geographical distance, and climatic difference, and evaluated the relative importance of various factors (i.e., climate, topography and history) in shaping patterns of beta diversity. Sørensen dissimilarity indices indicated that patterns of species turnover among sites dominated the QTP. We also found that patterns of both taxonomic and phylogenetic beta diversity were significantly related to geographical distance and climatic difference. The environmental factors that contributed most to these patterns of beta diversity include annual precipitation, mean annual temperature, climatic gradients and climatic instability. Hierarchical dendrograms of dissimilarity and non-metric multidimensional scaling ordination based on phylogenetic beta diversity data identified ten floristic subregions in the QTP. Our results suggest that the contemporary environment and historical climate changes have filtered species composition among sites and eventually determined beta diversity patterns of plants in the QTP.

Elevational patterns of seed plants and the driving mechanisms in the Himalaya.

The Himalaya is an important biodiversity hotspot on earth, which is of great significance to study the elevational gradients in plant diversity and its influencing factors for further revealing the formation of biodiversity and conservation. In this study, we measured the elevational range of 11886 seed plant species and different growth-forms (7918 herbaceous species, 2587 shrub species, and 1388 tree species) in the Himalaya. Using the optimal fitted regression models, we found that species richness and phylogenetic diversity of seed plants in the Himalaya mainly showed unimodal curves with the increases of elevation. The species richness and phylogenetic diversity of all species, trees, shrubs and herbaceous species reached the maximum value at the elevation of about 2000, 1000, 1600 and 3000 m, respectively. The results of partial regression and hierarchical partitioning analysis showed that climate and topography together drove the elevational gradient in plant diversity. Among these, mean annual temperature and annual precipitation contributed greatly to the elevational pattern, while surface area ratio and topographic heterogeneity had little influence. Compared with all species and herbaceous species, the elevational gradients of trees and shrubs plants were affected to a greater extent by the interaction between climate and topography.

Identification of performance and cost in a new backwash method to clean the UF membrane: backwashing with low dosage of NaClO.

Ultrafiltration (UF) is widely used in wastewater reclamation treatments. Conventional backwashing is usually performed at regular time intervals (10-120 min) with permeate and without the addition of chemicals. Chemical enhanced backwashing (CEB) is usually applied after 70-90 filtration cycles with added chemicals. These cleaning methods cause membrane fouling and require costly chemicals. Instead of conventional backwashing, we propose herein a new backwashing method involving backwashing the effluent with low doses of sodium hypochlorite (NaClO) named as BELN. The performance and cost of UF backwashing were investigated with Beijing wastewater reclamation treatment. The results showed that the transmembrane pressure (TMP) increased from 33.2 to 48.2 kPa during hydraulic backwashing after 80 filtration cycles but increased from 33.3 to 39.3 kPa during backwashing with a low NaClO content of 20 mg/L. It was also noticed that the hydraulic-irreversible fouling index decreased from 5.58 × 10-3 m2/L to 3.58 × 10-3 m2/L with the new method. According to the three-dimensional fluorescence excitation-emission (3D-EEM), the response increased from 11.9 to 15.2% with BELN. Protein-like material was identified as the main component causing membrane fouling by blocking the membrane pores. The results indicated that the low dosage of NaClO effectively stripped the fouling layer. Finally, based on an economic evaluation, the capacity of the UF process was increased from 76,959 to 109,133 m3/d with the new method. The amount of NaClO consumed for Beijing wastewater reclamation treatment was similarly compared with the conventional backwashing in per year under BELN. The new method has good potential for application.

Severe Acute Respiratory Syndrome Coronavirus 2 ORF8 Protein Inhibits Type I Interferon Production by Targeting HSP90B1 Signaling.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global pandemic that has currently infected over 430 million individuals worldwide. With the variant strains of SARS-CoV-2 emerging, a region of high mutation rates in ORF8 was identified during the early pandemic, which resulted in a mutation from leucine (L) to serine (S) at amino acid 84. A typical feature of ORF8 is the immune evasion by suppressing interferon response; however, the mechanisms by which the two variants of ORF8 antagonize the type I interferon (IFN-I) pathway have not yet been clearly investigated. Here, we reported that SARS-CoV-2 ORF8L and ORF8S with no difference inhibit the production of IFN-ß, MDA5, RIG-I, ISG15, ISG56, IRF3, and other IFN-related genes induced by poly(I:C). In addition, both ORF8L and ORF8S proteins were found to suppress the nuclear translocation of IRF3. Mechanistically, the SARS-CoV-2 ORF8 protein interacts with HSP90B1, which was later investigated to induce the production of IFN-ß and IRF3. Taken together, these results indicate that SARS-CoV-2 ORF8 antagonizes the RIG-I/MDA-5 signaling pathway by targeting HSP90B1, which subsequently exhibits an inhibitory effect on the production of IFN-I. These functions appeared not to be influenced by the genotypes of ORF8L and ORF8S. Our study provides an explanation for the antiviral immune suppression of SARS-CoV-2 and suggests implications for the pathogenic mechanism and treatment of COVID-19.

Enterovirus A71 utilizes host cell lipid ß-oxidation to promote its replication.

Enterovirus A71 (EV-A71) is a major pathogen that causes severe and fatal cases of hand-foot-and-mouth disease (HFMD), which is an infectious disease that endangers children's health. However, the pathogenic mechanisms underlying these severe clinical and pathological features remain incompletely understood. Metabolism and stress are known to play critical roles in multiple stages of the replication of viruses. Lipid metabolism and ER stress is an important characterization post viral infection. EV-A71 infection alters the perturbations of intracellular lipid homeostasis and induces ER stress. The characterizations induced by viral infections are essential for optimal virus replication and may be potential antiviral targets. In this study, we found that the addition of the chemical drug of ER stress, PKR IN, an inhibitor, or Tunicamycin, an activator, could significantly reduce viral replication with the decrease of lipid. The replication of viruses was reduced by Chemical reagent TOFA, an inhibitor of acetyl-CoA carboxylase (ACC) or C75, an inhibitor of fatty acid synthase (FASN), while enhanced by oleic acid (OA), which is a kind of exogenous supplement of triacylglycerol. The pharmacochemical reagent of carnitine palmitoyltransferase 1 (CPT1) called Etomoxir could knock down CPT1 to induce EV-A71 replication to decrease. This suggests that lipid, rather than ER stress, is the main factor affecting EV-A71 replication. In conclusion, this study revealed that it is the ß-oxidation of lipid that plays a core role, not ER stress, which is only a concomitant change without restrictive effect, on virus replication.