Pettersonvognsen4129

Despite the growing number of investigations on microbial succession during the last decade, most of our knowledge on primary succession of bacteria in natural environments comes from conceptual models and/or studies of chronosequences. Successional patterns of litter-degrading bacteria remain poorly documented, especially in undisturbed environments. Here we conducted an experiment with tank bromeliads as natural freshwater microcosms to assess major trends in bacterial succession on two leaf-litter species incubated with or without animal exclusion. We used amplicon sequencing and a co-occurrence network to assess changes in bacterial community structure according to treatments. Alpha-diversity and community complexity displayed the same trends regardless of the treatments, highlighting that primary succession of detrital-bacteria is subject to resource limitation and biological interactions, much like macro-organisms. Shifts in bacterial assemblages along the succession were characterized by an increase in uncharacterized taxa and potential N-fixing bacteria, the latter being involved in positive co-occurrence between taxa. These findings support the hypothesis of interdependence between taxa as a significant niche-based process shaping bacterial communities during the advanced stage of succession. © FEMS 2020.In this study, 52 Streptococcus suis (S. Blasticidin S in vitro suis) isolates from pigs in southern China were divided into four known sequence types (STs) and six new STs, using multilocus sequence typing. Ten representative isolates were selected from 10 STs for the analysis of whole genome sequences. Virulence was assessed in 10 isolates, which were classified into three pathogenic groups. The prevalence of virulence-associated factors (VFs) in moderately pathogenic group was higher than that in highly pathogenic group. The isolates from ST1 complex and serotype 2 were allocated to moderately pathogenic group, while the isolates from highly pathogenic group belonged to the non-ST1 complex and non-serotype 2. Three clusters were obtained based on MLST sequences, cluster Ⅲ isolates from the nasal cavity of healthy pigs were classified into highly pathogenic group and showed many peculiarities compared with cluster I and Ⅱ isolates in virulence genotypes, genetic typing, and pathogenesis, indicating a potential independent evolutionary line. Our results suggest that S. suis infections in China are becoming more complicated with constantly mutating isolates, which makes it difficult to distinguish their virulence by recognized typing methods. Thus, increased investigation and monitoring of these infections should be a priority for the swine industry in China. © FEMS 2020.Investigations into the potential for pharmacological inhibition of the aging process and the onset of age-related disease are increasingly garnering attention. Here, we analyzed the antiaging properties of natural compounds derived from several marine bacteria in vitro and in vivo using the fission yeast Schizosaccharomyces pombe. The Pseudoalteromonas flavipulchra STILL-33 extract exhibited high antioxidant and antiglycation activities in vitro. We then characterized two antioxidant active fractions isolated from this extract. In addition, we showed that the P. flavipulchra STILL-33 extract or either of its two active fractions (Fractions 1 and 2) could extend the longevity of fission yeast. Moreover, the particular extract and two active fractions were found to induce mitochondrial activity and to delay the G1 phase of the fission yeast cell cycle, perhaps by improving the aging process. The P. flavipulchra STILL-33 extract and Fraction 1 also increased the expression of the catalase-encoding ctt1+ gene, and thereby decreased the reactive oxygen species level. Structural analysis showed that Fraction 1 was dominated by l-arginine and ipriflavone, and we showed indeed that the two corresponding commercial products increase the fission yeast lifespan. As for fraction 2 was identified as the putative structure of butamben. Together, these results should facilitate the discovery of additional antiaging compounds from P. flavipulchra and ultimately the development of novel antiaging compounds for pharmaceutical use. © FEMS 2020.INTRODUCTION In this research, the authors attempted to ascertain whether or not the Root Cause Analysis Event Support and Engagement Team (RESET) investigates the use of U.S. Army aviation-based techniques by staff members or organizations in which serious obstetrical events have occurred. Root cause analysis (RCA), originating in the manufacturing and engineering sectors, attempts to elucidate an underlying cause of a problem. Most recently, this process has been applied to the investigation of medical error. RESET was established in order to perform centralized investigation of significant medical error within U.S. Army medical and dental treatment facilities based on request from a hospital commander or general officer. Significant obstetric events are high profile, discussed in multiple safety forums, and an area of close RESET focus. Yet it is unclear if RESET investigates the use of aviation-based techniques by staff and/or organizations involved in serious obstetrical events. Therefore the present surord University Press on behalf of the Association of Military Surgeons of the United States. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.Bacterial communities are crucial to soil ecosystems and are known to be sensitive to environmental changes. However, our understanding of how present-day soil bacterial communities remain impacted by historic land uses is limited; implications for their functional potential are especially understudied. Through 16S rRNA gene amplicon and shotgun metagenomic sequencing, we characterized the structure and functional potential of soil bacterial communities after land use conversion. Sites converted from pine plantations to dairy pasture were sampled five- and eight-years post conversion. The bacterial community composition and functional potential at these sites were compared to long-term dairy pastures and pine forest reference sites. Bacterial community composition and functional potential at the converted sites differed significantly from those at reference sites (P = 0.001). On average, they were more similar to those in the long-term dairy sites and showed gradual convergence (P = 0.001). Differences in composition and functional potential were most strongly related to nutrients such as nitrogen, Olsen P and the carbon to nitrogen ratio. Genes related to the cycling of nitrogen, especially denitrification, were underrepresented in converted sites compared to long-term pasture soils. Together, our study highlights the long-lasting impacts land use conversion can have on microbial communities, and the implications for future soil health and functioning. © FEMS 2020.Correction for 'Nanoparticle size and chemical modification play a crucial role in the interaction of nano gold with the brain extent of accumulation and toxicity' by Nouf N. Mahmoud et al., Biomater. Sci., 2020, DOI 10.1039/c9bm02072a.In this study, two novel organic ligands, bis(salicylaldehyde)pyrazino-1,10-phenanthroline-7,10-dicarbohydrazide (L) and bis(salicylaldehyde)-1,10-phenanthroline-7,10-dicarbohydrazide (L1), were synthesized. These ligands were used to react with lanthanide(iii) acetate to obtain complexes 1-6, namely, [Dy5(L)2(CH3COO)5(CH3OH)(μ3-OH)(μ2-OH)(H2O)]·2CH3OH (1), [Tb5(L)2(CH3COO)5(CH3OH)(μ3-OH)(μ2-OH)(H2O)]·3CH3OH (2), [Gd5(L)2(CH3COO)5(CH3OH)(μ3-OH)(μ2-OH)(H2O)]·3CH3OH (3), [Dy5(L1)2(μ2-OH)(μ3-OH)(CH3COO)5(CH3OH)(H2O)2]·2H2O (4), [Dy5(L1)2(μ3-OH)(CH3COO)6(CH3OH)3]·CH3OH (5), and [Dy5(L1)2(μ2-OH)2(μ3-OH)(CH3COO)4(CH3OH)(H2O)2]·CH3OH (6). Fluorescence studies demonstrated that complexes 1-6 show appreciable fluorescence in the yellow-green region. In vitro antitumor screening revealed that complex 1 exhibits better inhibitory activities than the commercial anticancer drug cisplatin against SK-OV-3 and A549 tumor cell lines, with IC50 values of 8.09 ± 1.25 and 13.26 ± 0.39 μM, respectively. All six complexes showed low cytotoxicity toward normal human liver HL-7702 cells compared with cisplatin. Complexes 1 and 3 induced the highest apoptosis rate of SK-OV-3/DDP cells. They also bind to DNA via an intercalative mode with the binding constant Kq values of 1.6 × 104 and 1.19 × 104 L mol-1, respectively. Confocal fluorescence imaging ascertained that complexes 1 and 3 are primarily localized in the mitochondria. Further studies revealed that these complexes trigger SK-OV-3/DDP cell apoptosis via a mitochondrial dysfunction pathway, which is probably caused by the reduction of the mitochondrial membrane potential and the induction of reactive oxygen species production.Graphitic carbon nitrides (CNs) are potential candidate materials for the electro-catalytic industry due to their unique physical and chemical properties. However, to date, a full understanding of the electro-catalytic properties of CNs is still lacking. Herein, by using density functional theory calculations, we systematically investigate the catalytic performances in the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), N2 reduction reaction (NRR), and CO2 reduction reaction (CO2RR) of monolayer graphitic carbon nitrides (C1-xNx), C3N (x = 1/4), C2N (x = 1/3), and g-C3N4 (x = 4/7). We also evaluated the NRR activity of B doped C1-xNx, and the CO2RR activity of Cu and Pd modified C1-xNx. The cohesive energy and ab initio molecular dynamics (AIMD) results show that C3N, C2N, and g-C3N4 are stable at room temperature. The C3N-C1 site is predicted to deliver the best HER catalytic performance with a reaction Gibbs free energy (ΔGH*) of -0.03 eV (close to the ideal value (0 eV)). Among the studied C1-xNx materials, the C3N-C2 site is predicted to possess a favorable ηOER of 0.82 V for OER. Pure C3N, C2N, and g-C3N4 are not suitable for NRR and CO2RR. Due to the strong hybridization between the N 2p orbital and the B 2p orbital, the NRR performances of B doped BN-C2N, BN-C3N, and BN-g-C3N4 are greatly enhanced, with corresponding overpotential ηNRR of 0.57 V, 0.70 V, and 0.72 V, respectively. The transition metals Cu and Pd can enhance the CO2RR activity of C3N, C2N, and g-C3N4. The limiting potentials UL of pure C3N, C2N, and g-C3N4 are 0.96 V, 0.86 V, and 2.37 V, respectively, while these values are 0.63 V, 0.68 V, and 0.77 V with Cu or Pd modification. This work provides deep understanding of the catalytic properties of monolayer C1-xNx and guidance for synthesizing higher activity catalysts in the future.The understanding of phase transformation upon activation, reaction and deactivation of catalysts is of prime importance for tailoring catalysts with better performances. Herein we combined Quick-EXAFS and Raman spectroscopies in operando conditions through the monitoring of reaction products by mass spectrometry in order to study in depth active species and deactivating ones for Ethanol Steam Reforming reaction. Quick-EXAFS data analyzed by multivariate analysis allows one to determine the nickel and copper species involved during the activation of a Ni-Cu hydrotalcite-like precursors. Upon reaction and regeneration monitoring, Raman spectroscopy combined with mass spectrometry highlights the side products formed upon ESR leading to the formation of amorphous coke species encapsulating active metallic species and inducing catalyst deactivation. The coke encapsulation of active species was demonstrated by the simultaneous observation of oxidation of nickel and copper as soon as the amorphous coke was burnt by the oxidative regeneration treatment.