Microorganisms in wastewater treatment plants (WWTPs) are essential for water purification to protect public and environmental health. However, their diversity and the factors that control it are poorly understood. Using a systematic global-sampling effort, we analyzed the 16S rRNA gene sequences from ~1,200 activated sludge samples taken from 269 WWTPs in 23 countries on 6 continents. Our analyses revealed that the global activated sludge bacterial communities contain ~1 billion bacterial phylotypes with a Poisson lognormal diversity distribution. Despite this high diversity, activated sludge has a small global core bacterial community (n = 28 OTUs) that is strongly linked to activated sludge performance. Meta-analyses with global datasets associate the activated sludge microbiomes most closely to freshwater populations. In contrast to macroorganism diversity, activated sludge bacterial communities show no latitudinal gradient. Furthermore, their spatial turnover is scale-dependent and appears to be largely driven by stochastic processes (dispersal, drift), although deterministic factors (temperature, organic input) also are important. Our findings enhance mechanistic understanding of the global diversity and biogeography of activated sludge bacterial communities within a theoretical ecology framework and have important implications for microbial ecology and wastewater treatment processes.

AbstractCellulose is synthesized by rosette structured cellulose synthase (CESA) complexes (CSCs), each of which is composed of multiple units of CESAs in three different isoforms. CSCs rely on vesicle trafficking for delivery to the plasma membrane where they catalyze cellulose synthesis. Although the rosette structured CSCs were observed decades ago, it remains unclear what amino acids in plant CESA that directly participate in cellulose catalytic synthesis. It is also not clear how the catalytic activity of CSCs influences their efficient transport at the subcellular level. Here we report characterization of the small molecule Endosidin20 (ES20) and present evidence that it represents a new CESA inhibitor. We show data from chemical genetic analyses, biochemical assays, structural modeling, and molecular docking to support our conclusion that ES20 targets the catalytic site of Arabidopsis CESA6. Further, chemical genetic analysis reveals important amino acids that potentially form the catalytic site of plant CESA6. Using high spatiotemporal resolution live-cell imaging, we found that inhibition of CSC catalytic activity by inhibitor treatment, or by creating missense mutation at amino acids in the predicted catalytic site, causes reduced efficiency in CSC transport to the plasma membrane. Our results show that the catalytic activity of plant CSCs is integrated with subcellular trafficking dynamics.One sentence summaryEndosidin20 targets cellulose synthase at the catalytic site to inhibit cellulose synthesis and the inhibition of catalytic activity reduces cellulose synthase complex delivery to the plasma membrane.

The sulfotransferase (SULTs) catalyzes the sulfonation of a multitude of xenobiotics, hormones and neurotransmitters. This review has summarised the SULT family in detail, the structure of the twelve known enzymes, in their four known groups (SULT1, SULT2, SULT4, and SULT6) and the substrates for each respective SULT. Hepatic sulfonation is a common phase II metabolic mechanism for increasing molecular hydrophilicity in preparation for biliary excretion or efflux across the hepatic basolateral membrane for subsequent renal clearance. To date, a total of 13 human cytosolic SULT genes have been identified which spread across four families; SULT1, SULT2, SULT4, and SULT6. The established structures of SULTs provide evidence for both enzyme/substrate and enzyme/cofactor binary complexes, consistent with a random bi-bi mechanism and ruling out an ordered mechanism in which binding of substrate requires binding of cofactor (or vice versa). Members of the SULT1 family have demonstrated the ability to sulfonate simple (small planar) phenols including estradiol, thyroid hormones, environmental xenobiotics and drugs. The SULT2 family members catalyze sulfonation of hydroxyl groups of steroids, such as androsterone, allopregnanolone, and dehydroepiandrosterone. As yet, no known substrate or function has been identified for the SULT4 family, and the SULT6B1 gene, expressed in the testis of primates, has neither the protein nor its enzymatic activity characterized. The extent of nucleotide variation found in members of the SULT gene family is similar to that observed for other groups of human genes. Substrate inhibition was observed for most substrates with a trend in maximum velocity (V(max)) of *1>*3>*2. There does appear to be an inter-ethnic/inter-racial difference in the incidence of the various SULT1A1 alleles also. There is mounting evidence to suggest that further research and understanding in the area of phase II metabolism and the SULT enzyme will have a great benefit in a clinical setting. Already research in the field is finding links with cancer and sulfonation-related disease, promising to deliver great advances in clinical practice in the future.

Glycolate oxidase (GLO) is a key enzyme in photorespiratory metabolism. Four putative GLO genes were identified in the rice genome, but how each gene member contributes to GLO activities, particularly to its isozyme profile, is not well understood. In this study, we analyzed how each gene plays a role in isozyme formation and enzymatic activities in both yeast cells and rice tissues. Five GLO isozymes were detected in rice leaves. GLO1 and GLO4 are predominately expressed in rice leaves, while GLO3 and GLO5 are mainly expressed in the root. Enzymatic assays showed that all yeast-expressed GLO members except GLO5 have enzymatic activities. Further analyses suggested that GLO1, GLO3 and GLO4 interacted with each other, but no interactions were observed for GLO5. GLO1/GLO4 co-expressed in yeast exhibited the same isozyme pattern as that from rice leaves. When either GLO1 or GLO4 was silenced, expressions of both genes were simultaneously suppressed and most of the GLO activities were lost, and consistent with this observation, little GLO isozyme protein was detected in the silenced plants. In contrast, no observable effect was detected when GLO3 was suppressed. Comparative analyses between the GLO isoforms expressed in yeast and the isozymes from rice leaves indicated that two of the five isozymes are homo-oligomers composed of either GLO1 or GLO4, and the other three are hetero-oligomers composed of both GLO1 and GLO4. Our current data suggest that GLO isozymes are coordinately controlled by GLO1 and GLO4 in rice, and the existence of GLO isozymes and GLO molecular and compositional complexities implicate potential novel roles for GLO in plants.

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