Small peptide signaling via OsCIF1/2 mediates Casparian strip formation at the root endodermal and nonendodermal cell layers in rice.

The Casparian strip (CS) is a ring-like lignin structure deposited between endodermal cells that forms an apoplastic barrier to control the selective uptake of nutrients in vascular plants. However, the molecular mechanism of CS formation in rice (Oryza sativa), which possesses one CS each in the endodermis and exodermis, is relatively unknown. Here, we functionally characterized CS INTEGRITY FACTOR1 (OsCIF1a, OsCIF1b), OsCIF2, and SCHENGEN3 (OsSGN3a, OsSGN3b) in rice. OsCIF1s and OsCIF2 were mainly expressed in the stele, while OsSGN3s localized around the CS at the endodermis. Knockout of all three OsCIFs or both OsSGN3s resulted in a discontinuous CS and a dramatic reduction in compensatory (less localized) lignification and suberization at the endodermis. By contrast, ectopic overexpression of OsCIF1 or OsCIF2 induced CS formation as well as overlignification and oversuberization at single or double cortical cell layers adjacent to the endodermis. Ectopic co-overexpression of OsCIF1 and SHORTROOT1 (OsSHR1) induced the formation of more CS-like structures at multiple cortical cell layers. Transcriptome analysis identified 112 downstream genes modulated by the OsCIF1/2-OsSGN3 signaling pathway, which is involved in CS formation and activation of the compensatory machinery in native endodermis and nonnative endodermis-like cell layers. Our results provide important insights into the molecular mechanism of CIF-mediated CS formation at the root endodermal and nonendodermal cell layers.

Tumor-repopulating cells evade ferroptosis via PCK2-dependent phospholipid remodeling.

Whether stem-cell-like cancer cells avert ferroptosis to mediate therapy resistance remains unclear. In this study, using a soft fibrin gel culture system, we found that tumor-repopulating cells (TRCs) with stem-cell-like cancer cell characteristics resist chemotherapy and radiotherapy by decreasing ferroptosis sensitivity. Mechanistically, through quantitative mass spectrometry and lipidomic analysis, we determined that mitochondria metabolic kinase PCK2 phosphorylates and activates ACSL4 to drive ferroptosis-associated phospholipid remodeling. TRCs downregulate the PCK2 expression to confer themselves on a structural ferroptosis-resistant state. Notably, in addition to confirming the role of PCK2-pACSL4(T679) in multiple preclinical models, we discovered that higher PCK2 and pACSL4(T679) levels are correlated with better response to chemotherapy and radiotherapy as well as lower distant metastasis in nasopharyngeal carcinoma cohorts.

Three OsMYB36 members redundantly regulate Casparian strip formation at the root endodermis.

Plants have evolved a lignin-based Casparian strip (CS) in roots that restricts passive diffusion of mineral elements from the soil to the stele. However, the molecular mechanisms underlying CS formation in rice (Oryza sativa), which contains a CS at both the exodermis and endodermis, are poorly understood. Here, we demonstrate that CS formation at the rice endodermis is redundantly regulated by three MYELOBLASTOSIS (MYB) transcription factors, OsMYB36a, OsMYB36b, and OsMYB36c, that are highly expressed in root tips. Knockout of all three genes resulted in a complete absence of CS at the endodermis and retarded plant growth in hydroponic conditions and in soil. Compared with the wild-type, the triple mutants showed higher calcium (Ca) levels and lower Mn, Fe, Zn, Cu, and Cd levels in shoots. High Ca supply further inhibited mutant growth and increased Ca levels in shoots. Transcriptome analysis identified 1,093 downstream genes regulated by OsMYB36a/b/c, including the key CS formation gene OsCASP1 and other genes that function in CS formation at the endodermis. Three OsMYB36s regulate OsCASP1 and OsESB1 expression by directly binding to MYB-binding motifs in their promoters. Our findings thus provide important insights into the mechanism of CS formation at the endodermis and the selective uptake of mineral elements in roots.

The nuclear and mitochondrial genome assemblies of Tetragonisca angustula (Apidae: Meliponini), a tiny yet remarkable pollinator in the Neotropics.

BACKGROUND: The field of bee genomics has considerably advanced in recent years, however, the most diverse group of honey producers on the planet, the stingless bees, are still largely neglected. In fact, only eleven of the ~ 600 described stingless bee species have been sequenced, and only three using a long-read (LR) sequencing technology. Here, we sequenced the nuclear and mitochondrial genomes of the most common, widespread and broadly reared stingless bee in Brazil and other neotropical countries-Tetragonisca angustula (popularly known in Brazil as jataí). RESULTS: A total of 48.01 Gb of DNA data were generated, including 2.31 Gb of Pacific Bioscience HiFi reads and 45.70 Gb of Illumina short reads (SRs). Our preferred assembly comprised 683 contigs encompassing 284.49 Mb, 62.84 Mb of which (22.09%) corresponded to 445,793 repetitive elements. N50, L50 and complete BUSCOs reached 1.02 Mb, 91 contigs and 97.1%, respectively. We predicted that the genome of T. angustula comprises 17,459 protein-coding genes and 4,108 non-coding RNAs. The mitogenome consisted of 17,410 bp, and all 37 genes were found to be on the positive strand, an unusual feature among bees. A phylogenomic analysis of 26 hymenopteran species revealed that six odorant receptor orthogroups of T. angustula were found to be experiencing rapid evolution, four of them undergoing significant contractions. CONCLUSIONS: Here, we provided the first nuclear and mitochondrial genome assemblies for the ecologically and economically important T. angustula, the fourth stingless bee species to be sequenced with LR technology thus far. We demonstrated that even relatively small amounts of LR data in combination with sufficient SR data can yield high-quality genome assemblies for bees.

Impacts of Taxon-Sampling Schemes on Bayesian Tip Dating Under the Fossilized Birth-Death Process.

Evolutionary timescales can be inferred by molecular-clock analyses of genetic data and fossil evidence. Bayesian phylogenetic methods such as tip dating provide a powerful framework for inferring evolutionary timescales, but the most widely used priors for tree topologies and node times often assume that present-day taxa have been sampled randomly or exhaustively. In practice, taxon sampling is often carried out so as to include representatives of major lineages, such as orders or families. We examined the impacts of different densities of diversified sampling on Bayesian tip dating on unresolved fossilized birth-death (FBD) trees, in which fossil taxa are topologically constrained but their exact placements are averaged out. We used synthetic data generated by simulations of nucleotide sequence evolution, fossil occurrences, and diversified taxon sampling. Our analyses under the diversified-sampling FBD process show that increasing taxon-sampling density does not necessarily improve divergence-time estimates. However, when informative priors were specified for the root age or when tree topologies were fixed to those used for simulation, the performance of tip dating on unresolved FBD trees maintains its accuracy and precision or improves with taxon-sampling density. By exploring three situations in which models are mismatched, we find that including all relevant fossils, without pruning off those that are incompatible with the diversified-sampling FBD process, can lead to underestimation of divergence times. Our reanalysis of a eutherian mammal data set confirms some of the findings from our simulation study, and reveals the complexity of diversified taxon sampling in phylogenomic data sets. In highlighting the interplay of taxon-sampling density and other factors, the results of our study have practical implications for using Bayesian tip dating to infer evolutionary timescales across the Tree of Life. [Bayesian tip dating; eutherian mammals; fossilized birth-death process; phylogenomics; taxon sampling.].

Myricetin Acts as an Inhibitor of Type II NADH Dehydrogenase from Staphylococcus aureus.

BACKGROUND: Staphylococcus aureus is a common pathogenic microorganism in humans and animals. Type II NADH oxidoreductase (NDH-2) is the only NADH:quinone oxidoreductase present in this organism and represents a promising target for the development of anti-staphylococcal drugs. Recently, myricetin, a natural flavonoid from vegetables and fruits, was found to be a potential inhibitor of NDH-2 of S. aureus. The objective of this study was to evaluate the inhibitory properties of myricetin against NDH-2 and its impact on the growth and expression of virulence factors in S. aureus. RESULTS: A screening method was established to identify effective inhibitors of NDH-2, based on heterologously expressed S. aureus NDH-2. Myricetin was found to be an effective inhibitor of NDH-2 with a half maximal inhibitory concentration (IC50) of 2 µM. In silico predictions and enzyme inhibition kinetics further characterized myricetin as a competitive inhibitor of NDH-2 with respect to the substrate menadione (MK). The minimum inhibitory concentrations (MICs) of myricetin against S. aureus strains ranged from 64 to 128 µg/mL. Time-kill assays showed that myricetin was a bactericidal agent against S. aureus. In line with being a competitive inhibitor of the NDH-2 substrate MK, the anti-staphylococcal activity of myricetin was antagonized by MK-4. In addition, myricetin was found to inhibit the gene expression of enterotoxin SeA and reduce the hemolytic activity induced by S. aureus culture on rabbit erythrocytes in a dose-dependent manner. CONCLUSIONS: Myricetin was newly discovered to be a competitive inhibitor of S. aureus NDH-2 in relation to the substrate MK. This discovery offers a fresh perspective on the anti-staphylococcal activity of myricetin.

Functional and phylogenetic relationships link predators to plant diversity via trophic and non-trophic pathways.

Human-induced biodiversity loss negatively affects ecosystem function, but the interactive effects of biodiversity change across trophic levels remain insufficiently understood. We sampled arboreal spiders and lepidopteran larvae across seasons in 2 years in a subtropical tree diversity experiment, and then disentangled the links between tree diversity and arthropod predator diversity by deconstructing the pathways among multiple components of diversity (taxonomic, phylogenetic and functional) with structural equation models. We found that herbivores were major mediators of plant species richness effects on abundance, species richness, functional and phylogenetic diversity of predators, while phylogenetic, functional and structural diversity of trees were also important mediators of this process. However, the strength and direction differed between functional, structural and phylogenetic diversity effects, indicating different underlying mechanisms for predator community assembly. Abundance and multiple diversity components of predators were consistently affected by tree functional diversity, indicating that the variation in structure and environment caused by plant functional composition might play key roles in predator community assembly. Our study highlights the importance of an integrated approach based on multiple biodiversity components in understanding the consequences of biodiversity loss in multitrophic communities.

Tree dissimilarity determines multi-dimensional beta-diversity of herbivores and carnivores via bottom-up effects.

Global biodiversity decline and its cascading effects through trophic interactions pose a severe threat to human society. Establishing the impacts of biodiversity decline requires a more thorough understanding of multi-trophic interactions and, more specifically, the effects that loss of diversity in primary producers has on multi-trophic community assembly. Within a synthetic conceptual framework for multi-trophic beta-diversity, we tested a series of hypotheses on neutral and niche-based bottom-up processes in assembling herbivore and carnivore communities in a subtropical forest using linear models, hieratical variance partitioning based on linear mixed-effects models (LMMs) and simulation. We found that the observed taxonomic, phylogenetic and functional beta-diversity of both herbivorous caterpillars and carnivorous spiders were significantly and positively related to tree dissimilarity. Linear models and variance partitioning for LMMs jointly suggested that as a result of bottom-up effects, producer dissimilarities were predominant in structuring consumer dissimilarity, the strength of which highly depended on the trophic dependencies on producers, the diversity facet examined, and data quality. Importantly, linear models for standardized beta-diversities against producer dissimilarities implied a transition between niche-based processes such as environmental filtering and competitive exclusion, which supports the role of bottom-up effect in determining consumer community assembly. These findings enrich our mechanistic understanding of the 'Diversity Begets Diversity' hypothesis and the complexity of higher-trophic community assembly, which is fundamental for sustainable biodiversity conservation and ecosystem management.

Tree communities and functional traits determine herbivore compositional turnover.

There are many factors known to drive species turnover, although the mechanisms by which these operate are less clear. Based on comprehensive datasets from the largest tree diversity experiment worldwide (BEF-China), we used shared herbivore species (zeta diversity) and multi-site generalized dissimilarity modelling to investigate the patterns and determinants of species turnover of Lepidoptera herbivores among study plots across a gradient in tree species richness. We found that zeta diversity declined sharply with an increasing number of study plots, with complete changes in caterpillar species composition observed even at the fine spatial scale of our study. Plant community characteristics rather than abiotic factors were found to play key roles in driving caterpillar compositional turnover, although these effects varied with an increasing number of study plots considered, due to the varying contributions of rare and common species to compositional turnover. Our study reveals details of the impact of phylogeny- and trait-mediated processes of trees on herbivore compositional turnover, which has implications for forest management and conservation and shows potential avenues for maintenance of heterogeneity in herbivore communities.

Coelonin protects against PM2 .5 -induced macrophage damage via suppressing TLR4/NF-κB/COX-2 signaling pathway and NLRP3 inflammasome activation in vitro.

One of the important monitoring indicators of the air pollution is atmospheric fine particulate matter (PM2.5 ), which can induce lung inflammation after inhalation. Coelonin can alleviate PM2.5 -induced macrophage damage through anti-inflammation. However, its molecular mechanism remains unclear. We hypothesized that macrophage damage may involve the release of inflammatory cytokines, activation of inflammatory pathways, and pyrosis induced by inflammasome. In this study, we evaluated the anti-inflammation activity of coelonin in PM2.5 -induced macrophage and its mechanism of action. Nitric oxide (NO) and reactive oxygen species (ROS) production were measured by NO Assay kit and dichlorofluorescein-diacetate (DCFH-DA), and apoptosis were measured by Flow cytometry and TUNEL staining. The concentration of inflammatory cytokines production was measured with cytometric bead arrays and ELISA kits. The activation of NF-κB signaling pathway and NLRP3 inflammasome were measured by immunofluorescence, quantitative reverse transcription-polymerase chain reaction and western blot. As expected, coelonin pretreatment reduced NO production significantly as well as alleviated cell damage by decreasing ROS and apoptosis. It decreased generation of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in PM2.5 -induced RAW264.7 and J774A.1 cells. Moreover, coelonin markedly inhibited upregulating the expression of toll-like receptor (TLR)4 and cyclo-oxygenase (COX)-2, blocked activation of p-nuclear factor-kappa B (NF-κB) signaling pathway, and suppressed expression of NLRP3 inflammasome, ASC, GSDMD, IL-18 and IL-1ß. In conclusion, the results showed that coelonin could protect against PM2.5 -induced macrophage damage via suppressing TLR4/NF-κB/COX-2 signaling pathway and NLRP3 inflammasome activation in vitro.

Clinical and Preclinical Neuroimaging Changes in Spinocerebellar Ataxia Type 12: A Study of Three Chinese Pedigrees.

BACKGROUND: Spinocerebellar ataxia type 12 (SCA12) is a rare SCA subtype with unclear clinical and imaging features. Also, the radiological changes in prodromal and early stages remain unknown. METHODS: Ten symptomatic and two pre-symptomatic cases from three Chinese pedigrees received clinical assessments and imaging studies including routine magnetic resonance imaging (MRI), diffusion kurtosis imaging (DKI), and positron emission tomography (PET) using 18F-flurodeoxyglucose (FDG) to investigate glucose metabolism in brain and 18F-vesicle monoamine transporter 2 (VMAT2) to inspect the integrity of the dopaminergic neuron. Seventy-two healthy individuals were recruited as controls in the quantitative FDG-PET analysis. Imaging parameters were compared between symptomatic and presymptomatic cases with different disease durations. RESULTS: Patients displayed prominent action tremor, moderate ataxia, and subtle parkinsonism with poor levodopa-response. MRI showed extensive but heterogeneous cerebral atrophy, which was most evident in the frontoparietal lobes. Cerebellar atrophy was apparent in later stages. DKI detected impaired fibers in the cerebellar peduncles. In both symptomatic and pre-symptomatic cases, PET-CT showed an earlier FDG decline than atrophic changes in multiple regions, and the frontoparietal lobes were the earliest and most severe. However, the VMAT2 density were normal in the putamen and caudate nucleus of most cases (7/8). CONCLUSIONS: We first found that hypometabolism in the cerebral cortex, but not cerebellum, is an early and prominent change in SCA12. The integrity of presynaptic dopaminergic neurons remains largely spared during the whole disease process.

Aflatoxin B1 causes oxidative stress and apoptosis in sheep testes associated with disrupting rumen microbiota.

Aflatoxin B1 (AFB1) is an unavoidable environmental pollutant commonly found in feed and foodstuffs. It is the most toxic one of all the aflatoxins, which can cause severe impairment to testicular development and function. Yet, the underlying mechanisms of reproductive toxicity in rams sheep remain inconclusive. The study was designed to explore the effects of AFB1 on sheep testes through rumen-microbiota, oxidative stress and apoptosis. Six-month-old male Dorper rams (n = 6) were orally administrated with 1.0 mg/kg AFB1 (dissolved in 20 mL 4% ethanol) 24 h before the experiment. At the same time, rams in the control group (n = 6) were intragastrically administrated with 20 mL 4% ethanol. It was observed that acute AFB1 poisoning had significant (p < 0.05) toxin residue in the testis and could cause testicular histopathological damage. AFB1 stimulated the secretion of plasma testosterone level through regulating testosterone synthesis-related genes (StAR, 3ß-HSD, CYP11A1, and CYP17A1), which are accompanied by the increase of oxidative stress and testicular apoptosis that had a close relationship with the regulation of testosterone secretion. Interestingly, we observed rumen dysbacteriosis and decreased the abundances of Prevotella, Succiniclasticum, CF231, Ruminococcus, and Pseudobutyrivibrio in AFB1-exposed sheep, which were negatively correlated to the testosterone synthesis-related gene levels. Taken together, our findings indicated that AFB1 induced testicular damage and testicular dysfunction, which is related to testicular oxidative stress and apoptosis involved in rumen dysbacteriosis in sheep.

The WRKY Transcription Factor OsWRKY54 Is Involved in Salt Tolerance in Rice.

Salt stress is a critical limiting factor for rice growth and production. Although numerous salt-tolerant genes have been identified, the mechanism underlying salt stress tolerance in rice remains unclear. This study reports the need for an uncharacterized WRKY transcription factor OsWRKY54 for rice salt-tolerance. Salt stress resulted in a rapid induction of OsWRKY54 expression in roots. Immunostaining analysis showed that it was mainly expressed in the stele. The loss of OsWRKY54 resulted in greater Na accumulation in shoots and enhanced sensitivity of rice plants to salt stress. The real-time quantitative PCR (qRT-PCR) and transcriptome analysis revealed that OsWRKY54 regulated the expression of some essential genes related to salt tolerance, such as OsNHX4 and OsHKT1;5. Furthermore, OsWRKY54 was found to regulate OsHKT1;5 expression by directly binding to the W-box motif in its promoter. Thus, these results indicated that OsWRKY54 was a critical regulatory factor in salt tolerance in rice.

A Simulation-Based Evaluation of Tip-Dating Under the Fossilized Birth-Death Process.

Bayesian molecular dating is widely used to study evolutionary timescales. This procedure usually involves phylogenetic analysis of nucleotide sequence data, with fossil-based calibrations applied as age constraints on internal nodes of the tree. An alternative approach is tip-dating, which explicitly includes fossil data in the analysis. This can be done, for example, through the joint analysis of molecular data from present-day taxa and morphological data from both extant and fossil taxa. In the context of tip-dating, an important development has been the fossilized birth-death process, which allows non-contemporaneous tips and sampled ancestors while providing a model of lineage diversification for the prior on the tree topology and internal node times. However, tip-dating with fossils faces a number of considerable challenges, especially, those associated with fossil sampling and evolutionary models for morphological characters. We conducted a simulation study to evaluate the performance of tip-dating using the fossilized birth-death model. We simulated fossil occurrences and the evolution of nucleotide sequences and morphological characters under a wide range of conditions. Our analyses of these data show that the number and the maximum age of fossil occurrences have a greater influence than the degree of among-lineage rate variation or the number of morphological characters on estimates of node times and the tree topology. Tip-dating with the fossilized birth-death model generally performs well in recovering the relationships among extant taxa but has difficulties in correctly placing fossil taxa in the tree and identifying the number of sampled ancestors. The method yields accurate estimates of the ages of the root and crown group, although the precision of these estimates varies with the probability of fossil occurrence. The exclusion of morphological characters results in a slight overestimation of node times, whereas the exclusion of nucleotide sequences has a negative impact on inference of the tree topology. Our results provide an overview of the performance of tip-dating using the fossilized birth-death model, which will inform further development of the method and its application to key questions in evolutionary biology.

Multi-trophic communities re-establish with canopy cover and microclimate in a subtropical forest biodiversity experiment.

Plant diversity affects multi-trophic communities, but in young regrowth forests, where forest insects are in the process of re-establishment, other biotic and also abiotic factors might be more important. We studied cavity-nesting bees, wasps and their natural enemies along an experimental tree diversity gradient in subtropical South-East China. We compared insect communities of experimental young forests with communities of established natural forests nearby the experiment and tested for direct and indirect effects of tree diversity, tree basal area (a proxy of tree biomass), canopy cover and microclimate on bee and wasp community composition, abundance and species richness. Finally, we tested if the trophic levels of bees, herbivore-hunting wasps, spider-hunting wasps and their natural enemies respond similarly. Forest bee and wasp community composition re-established towards communities of the natural forest with increasing tree biomass and canopy cover. These factors directly and indirectly, via microclimatic conditions, increased the abundance of bees, wasps and their natural enemies. While bee and wasp species richness increased with abundance and both were not related to tree diversity, abundance increased directly with canopy cover, mediated by tree biomass. Abundance of natural enemies increased with host (bee and wasp) abundance irrespective of their trophic position. In conclusion, although maximizing tree diversity is an important goal of reforestation and forest conservation, rapid closure of canopies is also important for re-establishing communities of forest bees, wasps and their natural enemies.

Aflatoxin B1 alters meat quality associated with oxidative stress, inflammation, and gut-microbiota in sheep.

Aflatoxin B1 (AFB1) is an unavoidable contaminant in animal feed and agricultural products. AFB1 has been found to impair the liver and kidney function of sheep. However, few data are available, which explain the toxic damage of AFB1 exposure on meat quality. In the study, male Dorper RAMS sheep (6-month-old) were orally administrated with AFB1 at the dose of 1 mg/kg body weight once. The body temperature, serum biochemistry, meat quality-related parameters, oxidation indicators in meat and serum, the mRNA expression of pro-inflammatory cytokines and anti-inflammatory, and microbiota composition of feces were measured 24 h after AFB1 exposure. The results showed that the body temperature was slightly increased, the mental state of mutton sheep was suppressed, and biochemical indicators were significantly changed after AFB1 exposure. AFB1 impaired mutton quality reflected by the structure of muscle fibers was changed, and increased muscle drip loss and lightness (L*), and decreased muscle redness (a*). Moreover, we found that AFB1 caused changes in the oxidative stress indicators T-SOD, T-AOC, MDA, GSH level, and GSH/GSSG ratio, and inflammation damage of mutton reflected by increasing pro-inflammatory TNF-α and reducing anti-inflammatory IL-10 mRNA levels, disrupts the secretion of inflammatory factors, and changed the composition of gut microbiota reflected by significantly increased Firmicutes/Bacteroidetes ratio and decreased the abundances of Butyrivibrio, which are related to the quality of the mutton. In summary, gut microbiota participates in AFB1 to damage mutton quality, which may be co-mediated by oxidative stress, inflammation, and gut microbiota.

Distally Based Perforator-Plus Sural Neurocutaneous Flap with High or Low Pivot Point: Anatomical Considerations and a Retrospective Study of a Clinical Series of 378 Flaps.

BACKGROUND: This study is to describe the distribution of natural true anastomoses associated with the distally based perforator-plus sural neurocutaneous flap (sural flap), summarize our experience in the flap with high pivot point, and compare the outcomes between the flaps with high and low pivot points. METHODS: Five amputated lower limbs were perfused, and the integuments were radiographed. We retrospectively analyzed 378 flaps, which were divided into two groups: pivot points located ≤8.0 cm (low pivot point group) and >8.0 cm (high pivot point group) proximal to the tip of the lateral malleolus. Partial necrosis rates were compared between two groups. RESULTS: The arterial chain surrounding the sural nerve was linked by true anastomoses from the intermalleolar line to popliteal crease. True anastomoses existed among peroneal perforators and between these perforators and the arterial chain. There were 93 flaps with high pivot point and 285 flaps with low pivot point. Partial necrosis rates were 16 and 9.1% in the high and low pivot point group (p = 0.059), respectively. CONCLUSION: True anastomosis connections among peroneal perforators and the whole arterial chain around sural nerve enable the sural flap to survive with a greater length. The sural flap with high pivot point is a good option for reconstructing soft-tissue defects in the middle and distal leg, ankle, and foot, particularly when the lowest peroneal perforator presents damage, greater distance to the defects, discontinuity with the donor site, or anatomical variation.

[Study on patterns and characteristics of in vivo tissue distribution of anti-inflammatory extract of Tetrastigma hemsleyanum aerial part in healthy and inflammatory pathological model rats].

The concentrations of seven anti-inflammatory components in blood and tissues were determined by UPLC-MS/MS after oral administration of Tetrastigma hemsleyanum aerial part(THAA) in healthy and inflammatory pathological model rats. The determination was carried out by using positive and negative ion switching technique, and multiple reaction monitoring(MRM) mode. The tissue distributions of the seven components in different physiological states were compared, and the patterns and characteristics of the effective components of THAA were studied. The results revealed that the seven effective components have large drug-time-curve areas(AUC) in heart, brain, small intestine, and stomach in both normal rats and inflammatory pathological model rats. This suggests that the anti-inflammatory effective component groups in THAA extract can all penetrate the blood-brain barrier, and have a large distribution area in gastrointestinal tract. It is inferred that gastrointestinal reabsorption may be one of the causes of the bimodal distribution of the drug-time curve of the drug blood distribution graph. As compared to normal rats, the effective component groups in THAA extract have higher drug-time curve area(AUC) in heart, brain, small intestine, stomach, liver, spleen, lung, kidney, and muscle of inflammatory pathological model rats. Among them, the effective component groups have the largest distribution area in heart, brain, small intestine, and stomach. This suggests that the binding force of organ tissues and drugs in the body may change under pathological conditions. It is speculated that the heart, brain, small intestine, and stomach may be the target tissues of THAA to produce anti-inflammatory effect. The retention times of THAA effective component groups in various organ tissues of rats in different physiological states are all relatively short, and do not have much difference. This suggests that no effective component accumulates in body, and that the pathological state of inflammation does not affect the onset times of the effective component groups. This experiment elucidates the patterns and characteristics of the in vivo target-effecting tissue distribution of THAA anti-inflammatory extract, and provides an experimental basis for clinical treatment.

The Antibacterial Properties of 4, 8, 4', 8'-Tetramethoxy (1,1'-biphenanthrene) -2,7,2',7'-Tetrol from Fibrous Roots of Bletilla striata.

Biphenanthrene compound, 4, 8, 4', 8'-tetramethoxy (1, 1'-biphenanthrene)-2, 7, 2', 7'-tetrol (LF05), recently isolated from fibrous roots of Bletilla striata, exhibits antibacterial activity against several Gram-positive bacteria. In this study, we investigated the antibacterial properties, potential mode of action and cytotoxicity. Minimum inhibitory concentrations (MICs) tests showed LF05 was active against all tested Gram-positive strains, including methicillin-resistant Staphylococcus aureus (MRSA) and staphylococcal clinical isolates. Minimum bactericidal concentration (MBC) tests demonstrated LF05 was bactericidal against S. aureus ATCC 29213 and Bacillus subtilis 168 whereas bacteriostatic against S. aureus ATCC 43300, WX 0002, and other strains of S. aureus. Time-kill assays further confirmed these observations. The flow cytometric assay indicated that LF05 damaged the cell membrane of S. aureus ATCC 29213 and B. subtilis 168. Consistent with this finding, 4 × MIC of LF05 caused release of ATP in B. subtilis 168 within 10 min. Checkerboard test demonstrated LF05 exhibited additive effect when combined with vancomycin, erythromycin and berberine. The addition of rat plasma or bovine serum albumin to bacterial cultures caused significantly loss in antibacterial activity of LF05. Interestingly, LF05 was highly toxic to several tumor cells. Results of these studies indicate that LF05 is bactericidal against some Gram-positive bacteria and acts as a membrane structure disruptor. The application of biphenanthrene in the treatment of S. aureus infection, especially local infection, deserves further study.

Host functional and phylogenetic composition rather than host diversity structure plant-herbivore networks.

Declining plant diversity alters ecological networks, such as plant-herbivore interactions. However, our knowledge of the potential mechanisms underlying effects of plant species loss on plant-herbivore network structure is still limited. We used DNA barcoding to identify herbivore-host plant associations along declining levels of tree diversity in a large-scale, subtropical biodiversity experiment. We tested for effects of tree species richness, host functional and phylogenetic diversity, and host functional (leaf trait) and phylogenetic composition on species, phylogenetic and network composition of herbivore communities. We found that phylogenetic host composition and related palatability/defence traits but not tree species richness significantly affected herbivore communities and interaction network complexity at both the species and community levels. Our study indicates that evolutionary dependencies and functional traits of host plants determine the composition of higher trophic levels and corresponding interaction networks in species-rich ecosystems. Our findings highlight that characteristics of the species lost have effects on ecosystem structure and functioning across trophic levels that cannot be predicted from mere reductions in species richness.