The DsrD functional marker protein is an allosteric activator of the DsrAB dissimilatory sulfite reductase.

Dissimilatory sulfur metabolism was recently shown to be much more widespread among bacteria and archaea than previously believed. One of the key pathways involved is the dsr pathway that is responsible for sulfite reduction in sulfate-, sulfur-, thiosulfate-, and sulfite-reducing organisms, sulfur disproportionators and organosulfonate degraders, or for the production of sulfite in many photo- and chemotrophic sulfur-oxidizing prokaryotes. The key enzyme is DsrAB, the dissimilatory sulfite reductase, but a range of other Dsr proteins is involved, with different gene sets being present in organisms with a reductive or oxidative metabolism. The dsrD gene codes for a small protein of unknown function and has been widely used as a functional marker for reductive or disproportionating sulfur metabolism, although in some cases this has been disputed. Here, we present in vivo and in vitro studies showing that DsrD is a physiological partner of DsrAB and acts as an activator of its sulfite reduction activity. DsrD is expressed in respiratory but not in fermentative conditions and a ΔdsrD deletion strain could be obtained, indicating that its function is not essential. This strain grew less efficiently during sulfate and sulfite reduction. Organisms with the earliest forms of dsrAB lack the dsrD gene, revealing that its activating role arose later in evolution relative to dsrAB.

Utility and Evaluation of Applied Project Management Processes Within a Large Multicountry Health Systems Development Project Conducted During the Coronavirus Disease 2019 (COVID-19) Pandemic.

The increasing trends in antimicrobial resistance (AMR) continue to pose a significant threat to human health, with grave consequences in low- and middle-income countries. In collaboration with local governments and microbiology laboratories in South Asian and Southeast Asian countries, the Capturing Data on Antimicrobial Resistance Patterns and Trends in Use in Regions of Asia (CAPTURA) project worked to identify gaps and expand the volume of existing AMR data to inform decision-makers on how to best strengthen their national AMR surveillance capacity. This article describes overall project management processes and the strategies implemented to address the disruptive impact of the coronavirus disease 2019 (COVID-19) pandemic on the project activities across diverse contexts in different countries. Also, it assesses in-country team's feedback on the conduct of activities and their overall impact on project completion. The strategies employed were tailored to the specific context of each country and included increased communication and collaboration among consortium partners and in-country teams, as well as hiring of additional in-country team members. This paper highlights the importance of local representation and capacities as well as real-time (virtual) engagement with stakeholders, ensuring close monitoring of the local situation and ability to tailor context-specific mitigation strategies to continue project implementation during disruptive external circumstances.

Substrate-Dependent Conformational Switch of the Noncubane [4Fe-4S] Cluster in Heterodisulfide Reductase HdrB.

The noncubane [4Fe-4S] cluster identified in the active site of heterodisulfide reductase (HdrB) displays a unique geometry among Fe-S cofactors found in metalloproteins. Here we employ resonance Raman (RR) spectroscopy and density functional theory (DFT) calculations to probe structural, electronic, and vibrational properties of the noncubane cluster in HdrB from a non-methanogenic Desulfovibrio vulgaris (Dv) Hildenborough organism. The immediate protein environment of the two neighboring clusters in DvHdrB is predicted using homology modeling. We demonstrate that in the absence of substrate, the oxidized [4Fe-4S]3+ cluster adopts a "closed" conformation. Upon substrate coordination at the "special" iron center, the cluster core translates to an "open" structure, facilitated by the "supernumerary" cysteine ligand switch from iron-bridging to iron-terminal mode. The observed RR fingerprint of the noncubane cluster, supported by Fe-S vibrational mode analysis, will advance future studies of enzymes containing this unusual cofactor.

DsrC is involved in fermentative growth and interacts directly with the FlxABCD-HdrABC complex in Desulfovibrio vulgaris Hildenborough.

DsrC is a key protein in dissimilatory sulfur metabolism, where it works as co-substrate of the dissimilatory sulfite reductase DsrAB. DsrC has two conserved cysteines in a C-terminal arm that are converted to a trisulfide upon reduction of sulfite. In sulfate-reducing bacteria, DsrC is essential and previous works suggested additional functions beyond sulfite reduction. Here, we studied whether DsrC also plays a role during fermentative growth of Desulfovibrio vulgaris Hildenborough, by studying two strains where the functionality of DsrC is impaired by a lower level of expression (IPFG07) and additionally by the absence of one conserved Cys (IPFG09). Growth studies coupled with metabolite and proteomic analyses reveal that fermentation leads to lower levels of DsrC, but impairment of its function results in reduced growth by fermentation and a shift towards more fermentative metabolism during sulfate respiration. In both respiratory and fermentative conditions, there is increased abundance of the FlxABCD-HdrABC complex and Adh alcohol dehydrogenase in IPFG09 versus the wild type, which is reflected in higher production of ethanol. Pull-down experiments confirmed a direct interaction between DsrC and the FlxABCD-HdrABC complex, through the HdrB subunit. Dissimilatory sulfur metabolism, where sulfur compounds are used for energy generation, is a key process in the ecology of anoxic environments, and is more widespread among bacteria than previously believed. Two central proteins for this type of metabolism are DsrAB dissimilatory sulfite reductase and its co-substrate DsrC. Using physiological, proteomic and biochemical studies of Desulfovibrio vulgaris Hildenborough and mutants affected in DsrC functionality, we show that DsrC is also relevant for fermentative growth of this model organism and that it interacts directly with the soluble FlxABCD-HdrABC complex that links the NAD(H) pool with dissimilatory sulfite reduction.

Redox loops in anaerobic respiration - The role of the widespread NrfD protein family and associated dimeric redox module.

In prokaryotes, the proton or sodium motive force required for ATP synthesis is produced by respiratory complexes that present an ion-pumping mechanism or are involved in redox loops performed by membrane proteins that usually have substrate and quinone-binding sites on opposite sides of the membrane. Some respiratory complexes include a dimeric redox module composed of a quinone-interacting membrane protein of the NrfD family and an iron­sulfur protein of the NrfC family. The QrcABCD complex of sulfate reducers, which includes the QrcCD module homologous to NrfCD, was recently shown to perform electrogenic quinone reduction providing the first conclusive evidence for energy conservation among this family. Similar redox modules are present in multiple respiratory complexes, which can be associated with electroneutral, energy-driven or electrogenic reactions. This work discusses the presence of the NrfCD/PsrBC dimeric redox module in different bioenergetics contexts and its role in prokaryotic energy conservation mechanisms.

Prevalence of adenovirus and rotavirus infection in immunocompromised patients with acute gastroenteritis in Portugal.

AIM: To characterize the prevalence of rotavirus (RV) and adenovirus (AdV) infections in immunocompromised patients with acute gastroenteritis. METHODS: The presence of RV and AdV (serotypes 40 and 41) was evaluated in 509 stool samples obtained between January 2009 and December 2010 from 200 immunocompromised patients (83 females and 117 males; median age 21 years old, range 0-72. The diagnosis of infection was performed as a routine procedure and the presence of RV and AdV (serotypes 40 and 41) was determined by immunochromatography using the RIDA(®) Quick Rota-Adeno-Kombi kit (r-Biopharm, Darmstadt, Germany). The data analysis and description of seasonal frequencies were performed using computer software IBM(®) SPSS(®) (Statistical Package for Social Sciences) Statistics version 20.0 for Mac. The frequencies of infection were compared into different age and gender groups by χ(2) test. RESULTS: The study revealed 12.4% AdV positive samples and 0.8% RV positive samples, which correspond to a prevalence of 6.5% and 1.5%, respectively. AdV was more frequent between October 2009 and April 2010, while RV was identified in April 2010 and July 2010. The stool analysis revealed that from the 509 samples, 63 (12.4%) were positive for AdV and 4 (0.8%) positive for RV, which by resuming the information of each patient, lead to an overall prevalence of AdV and RV of 6.5% (13/200 patients) and 1.5% (3/200 patients), respectively. The stratification of the analysis regarding age groups showed a tendency to an increased prevalence of infection in paediatric patients between 0-10 years old. Considering the seasonal distribution of these infections, our study revealed that AdV infection was more frequent between October 2009 and April 2010, while RV infection was characterized by two distinct peaks (April 2010 and July 2010). CONCLUSION: The overall prevalence of AdV and RV infection in immunocompromised patients with acute gastroenteritis was 8% and AdV was the most prevalent agent.

Adaptation to sustained nitrogen starvation by Escherichia coli requires the eukaryote-like serine/threonine kinase YeaG.

The Escherichia coli eukaryote-like serine/threonine kinase, encoded by yeaG, is expressed in response to diverse stresses, including nitrogen (N) starvation. A role for yeaG in bacterial stress response is unknown. Here we reveal for the first time that wild-type E. coli displays metabolic heterogeneity following sustained periods of N starvation, with the metabolically active population displaying compromised viability. In contrast, such heterogeneity in metabolic activity is not observed in an E. coli ∆yeaG mutant, which continues to exist as a single and metabolically active population and thus displays an overall compromised ability to survive sustained periods of N starvation. The mechanism by which yeaG acts, involves the transcriptional repression of two toxin/antitoxin modules, mqsR/mqsA and dinJ/yafQ. This, consequently, has a positive effect on the expression of rpoS, the master regulator of the general bacterial stress response. Overall, results indicate that yeaG is required to fully execute the rpoS-dependent gene expression program to allow E. coli to adapt to sustained N starvation and unravels a novel facet to the regulatory basis that underpins adaptive response to N stress.

Torta de mamona destoxificada para alimentação de poedeiras comerciais / Detoxified castor cake feed for laying hens

Objetivou-se com este experimento avaliar o efeito da inclusão de torta de mamona destoxificada (TMD) na ração de poedeiras comerciais sobre o desempenho e a qualidade interna e externa dos ovos. Foram utilizadas 200 poedeiras comerciais de 40 a 50 semanas de idade, da linhagem Hy-Line W-36®, com 1543±34g de peso corporal, que foram distribuídas em um delineamento inteiramente casualizado com cinco tratamentos (0, 5, 10, 15 e 20% de torta de mamona destoxificada na ração) com cinco repetições de oito aves cada. Foram avaliados o consumo de ração, a produção, o peso e a massa de ovos e a conversão alimentar. A qualidade interna foi avaliada por meio da unidade de Haugh, percentual de albúmen e de gema. A qualidade da casca foi medida pela espessura, densidade específica e percentual de casca. As variáveis de desempenho foram afetadas pela inclusão da TMD com resposta linear negativa para o consumo de ração e quadrática para produção de ovos, peso do ovo, massa do ovo e conversão alimentar, com os melhores níveis de 10,5, 5,7, 9,2 e 10,3% respectivamente. Não houve efeito significativo da inclusão da TMD para as variáveis de qualidade interna e externa dos ovos. Concluiu-se que a TMD pode ser incluída na ração de poedeiras em até 5,7% para otimizar o desempenho e não alterar a qualidade interna e externa dos ovos.

This experiment aimed to evaluate the use of detoxified castor cake (DCC) in the diet of laying hens on performance and internal and external quality of eggs. A total of 200 laying hens with 40-50 weeks of age, of Hy-Line W-36® line, with 1543±34g body weight, were distributed in a completely randomized design with five treatments (0, 5, 10, 15 and 20% of DCC in diet) with five replicates of eight birds each. The feed intake, egg production, egg weight, egg mass and feed conversion were evaluated. The egg internal quality was evaluated by Haugh unit, percentage of albumen and yolk. The shell quality was evaluated by the thickness, density and specific percentage of eggshell. The performance variables were affected by the inclusion of DCC with a negative linear response to food intake and quadratic for egg production, egg weight, egg mass and feed conversion, with the best levels of 10.5, 5.7, 9.2 and 10.3% respectively. There was no significant effect of DCC inclusion for the variables of egg quality. It is conclude that the DCC can be included in hens diets up to 5.7% to optimize performance and do not alter the internal and external quality of the eggs.