Encapsulating cesium lead halide (CsPbX3, X = Cl, Br, and I) perovskite quantum dots (PQDs) into stable shells has been proved to be an effective strategy for improving their stability,...

Three new actinopyrone derivatives, actinopyrones E−G (1, 3, and 4), together with three known analogues, PM050463 (2), actinopyrone D (5), and PM050511 (6), were isolated from Streptomyces sp. SCSIO ZS0520 derived from a deepsea hydrothermal vent. Their structures, complete with absolute configurations, were elucidated using extensive spectroscopic analyses combined with Mosher's method, ECD calculations, and bioinformatics analyses. These findings corrected the absolute configurations of previously reported actinopyrone analogues 2, 5, and 6 at C-3, C-9, and C-10. Notably, compound 6 displayed notable cytotoxicity against six human cell lines with IC 50 values of 0.26−2.22 μM. A likely biosynthetic pathway and annotations of protein function are proposed on the basis of bioinformatics analyses. Genes coding for methyltransferase and glycosyltransferase tailoring chemistries needed to generate final structures were notably absent from the biosynthetic gene cluster. Taken together, these results enable further bioengineering of the actinopyrones and related congeners as potential antitumor agents.

Real-time quantitative polymerase chain reaction (RT-qPCR) has been widely applied in gene expression and transcription abundance analysis because of its high sensitivity, good repeatability, and strong specificity. Selection of relatively stable reference genes is a precondition in order to obtain the reliable analysis results. However, little is known about evaluation of a set of reference genes through scientific experiments in Rubia plants. Here, 15 candidate reference genes were selected from R. yunnanensis transcriptome database and analyzed under abiotic stresses, hormone treatments, and different tissues. Among these 15 candidate reference genes, heterogeneous nuclear ribonucleoprotein (hnRNP), TATA binding protein (TBP), ribosomal protein L5 (RPL5), malate dehydrogenase (MDH), and elongation factor 1-alpha (EF-1α) were indicated as the five most stable reference genes by four statistical programs (geNorm, NormFinder, BestKeeper, and RefFinder). Ultimately, the validity of reference genes was confirmed by normalizing the expression of o-succinylbenzoate-CoA ligase (OSBL) and isochorismate synthase (ICS) involved in the anthraquinone biosynthesis pathway in different tissues and hormone treatments. Meanwhile, four other putative genes involved in the anthraquinone biosynthesis pathway were also normalized with the selected reference genes, which showed similar expression levels with those given by transcriptome data. This work is the first research that aims at a systematic validation on the stability of reference genes selected from R. yunnanensis transcriptome data and will be conducive to analyze gene expression in R. yunnanensis or other Rubia species.

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Miscanthus sinensis is a potential biofuel that is distributed widely in China, but with difficulties for decomposition and utilization due to the complexity of its fibrous cell walls. To detect whether M. sinensis could increase the population of rumen fibrolitic microbes, two16S rRNA gene libraries were constructed using ruminal samples from Xiangxi yellow cattle fed with either common mixed feedstuff (group C) or M. sinensis (group M), and the diversity of ruminal bacteria and archaea in the rumens of cattle of both groups was identified. Based on the comparative analysis of these two groups, the microbial composition in group C/M was found to be: Bacteroidetes (16.33 %/28.15 %), Firmicutes (68.88 %/60.92 %), Proteobacteria (10.71 %/3.78 %), Planctomycetes (0/0.84 %), Lentisphaerae (0/0.42 %), Spirochaetes (1.02 %/0) in the Bacteria domain and Thermoplasmata (13.09 %/46.67 %), Methanomicrobia (57.14 %/12.22 %) and uncultured archaea (29.76 %/41.11 %) in the Archaea domain, respectively. Moreover, through phylogenetic analysis, we also detected the increase of Bacteroidetes and the decrease of Methanomicrobia in group M. These results indicated that feeding cattle with M. sinensis will change the microbial composition in the rumen; the increased bacteroidetes may be responsible for digesting M. sinensis, which will benefit us in further screening for potentially valuable bio-enzymes.

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Most coagulation studies focus on pollutant removal or floc separation efficiency. However, to understand the mechanism of coagulation, it is necessary to explore the behavior of coagulation in terms of the interactions among the functional groups on the surface of the metal hydrolysis precipitates during the hydrolysis process. In this study, for the first time, aluminum sulfate (alum) was used to investigate such interactions over the whole process sequence of hydrolysis, coagulation, and crystallization with, and without (as a control), the presence of specific low molecular weight (LMW) (molecular weight < 1000 Da) organic compounds with different chemical bonds. It was observed that primary nanoparticles (NPs) of around 10 nm size were produced during the hydrolysis of alum. The presence of organic compounds was found to influence the coagulation performance by affecting the metal hydrolysis and the properties of the nanoparticles. At pH 7, ethylenediaminetetraacetic acid disodium salt (EDTA) delayed the time when the particles start to aggregate but increased the maximum size of the flocs, while citric acid caused the crystallization of amorphous hydrates and inhibited the coagulation performance. In contrast, glucose, benzoic acid (BEN), and tris­(hydroxymethyl)­aminomethane (THMAM) had no significant effect on the coagulation performance. Therefore, LMW organics can bond to the hydrolysis products of metal ions through key functional groups, such as carboxyl groups, and then affect the coagulation process. The experimental results show that the presence of LMW organics can change the surface properties and degree of crystallization of the primary NPs, thereby affecting the performance of coagulation.

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