Cubane-type tungsten-iron-sulfur clusters with a nitrogen atom in the core: terminal ligand substitutions and redox behaviors.

The lack of M-Fe-S (M = Mo or W) clusters incorporating a second period (2p) atom in the core has resulted in limited investigations and poor understanding of the physical and chemical properties of the M-Fe-S clusters closely related to the FeMo cofactor. In this work, systematic studies have been carried out to explore the chemical reactivities at the terminal ligand sites and the redox properties of a series of clusters comprising a [WFe3S3N] cubane core, based on the previously developed cluster [(Tp*)WFe3S3(µ3-NSiMe3)Cl3]1-. Substitutions of the terminal chlorides with ethanethiolate, methanethiolate, thiophenolate, p-thiocresolate and azide occurred smoothly, while the replacement of the chlorides with carbene ligands required the reduction of the precursor into [(Tp*)WFe3S3(µ3-NSiMe3)Cl3]2- first. The reduced cluster core could also be supported by thiophenolates as terminal ligands, but not thiolates or azides. It is remarkable that the thiophenolate ligated reduced cluster can be synthesized from the precursor [(Tp*)WFe3S3(µ3-NSiMe3)Cl3]1-via different synthetic routes, either reduction followed by substitution or substitution followed by reduction, either in situ or stepwise. This work indicates that terminal ligands contribute significantly to determine the chemical and physical properties of the clusters, even though they might affect the cluster core to a limited extent from a structural point of view, which raises the possibility of delicate control in regulating the physical/chemical properties of M-Fe-S clusters with a heteroleptic core incorporating 2p atom(s).

Stem-end Rot Caused by Lasiodiplodia brasiliense on Tobacco in China.

Tobacco (Nicotiana tabacum L.), is a major cash crop grown worldwide for its leaves, which are dried and fermented before being put in tobacco products. Tobacco production is seriously threatened by numerous diseases (Qiu et al. 2021). In August 2021, plants with stem-end rot were observed in a tobacco field in Zunyi City, Guizhou Province, China. Surveys indicated a 22 to 35% disease incidence in five counties. Symptoms of black necrosis appeared at the base of stems, and leaves turned yellow. To isolate the pathogen, diseased stems were cut into small segments and placed on potato dextrose agar (PDA) at 25°C in darkness for 3 to 5 days. To obtain pure cultures, hyphal tips from colonies were transferred to fresh PDA plates. A representative strain, GZAX 110, was used for further identification. The fungal colonies were initially gray, later deepening to smoke-gray. Conidiogenous cells were fully divided, discrete, transparent, thin-walled, smooth and cylindrical. Conidia matured slowly, were ellipsoid to ovoid, containing granular content, with a rounded apex. The base was largely truncated, and conidia became dark brown with one central septum, 21.0-30.0 × 12.0-18.0 µm. On water-agar medium, teleomorph structures were not observed. These characteristics suggested the fungus was Lasiodiplodia sp. (Netto et al. 2014). For further confirmation, genomic DNA was extracted using the CTAB method (Watanabe et al. 2010); and the ITS (internal transcribed spacer region of rDNA) and EF-1α (translation-elongation factor) regions were amplified with primer pairs ITS1/ITS4 and EF1-688F/EF1-1251R (Cruywagen et al. 2017), respectively. The ITS and EF-1α sequences (OM534558 and OM632673) were analyzed by BLASTN searches. The ITS sequence showed 100% identity (490/490 bp) to L. brasiliense strain AGQMy0011 (MW274145) and the EF-1ɑ sequence showed 100% identity (551/551 bp) to L. brasiliense strain EX1 (MF580811). A multilocus phylogenetic tree was constructed via the Maximum-likelihood (RAxML v.7.2.8) and Bayesian Inference (MrBayes v.3.2.1) analyses (Elsie et al. 2017) using combined ITS and EF1-α reference sequences of Lasiodiplodia species. Phylogenetic analysis showed that GZAX 110 clustered monophyletically with strains of L. brasiliense. Thus, the isolate GZAX 110 was confirmed as L. brasiliense. Pathogenicity of GZAX 110 was tested on tobacco plants at the eight leaf stage by attaching mycelial plugs (5 mm in diameter) to stems and leaves according to Cruywagen et al. (2017). Inoculated plants were kept in a greenhouse (16 h light/8 h darkness, 22℃, relative humidity >85%). Control plants were inoculated with PDA plugs. The experiment was repeated three times with five plants. Seven days after inoculation, dark brown necrosis was observed at inoculation sites on stems and leaves, while the control plants remained healthy. The pathogen was re-isolated from the inoculated sites and further validated as the same fungus through morphological and phylogenetic analyses. Previously, this fungus has been reported on Mangifera indica (mango) in China (Zhang et al. 2018), and apple (Martins et al. 2018) and papaya (Netto et al. 2014) in Brazil. However, to our knowledge, this is the first worldwide report of L. brasiliense causing stem-end rot on tobacco. This report provides information for future diagnosis and management of the disease.

Public trust, information sources and vaccine willingness related to the COVID-19 pandemic in Trinidad and Tobago: an online cross-sectional survey.

BACKGROUND: The response of populations to public health measures may rely on the degree to which the population trusts sources of information and institutions. There has been little research in this area in the Caribbean. This exploratory study aimed to evaluate public trust in information sources, confidence in institutions and COVID-19 vaccine willingness in Trinidad and Tobago. METHODS: An exploratory online survey was conducted in Trinidad and Tobago from November 10th to December 7th 2020. The survey instrument was a validated questionnaire developed by the World Health Organisation (WHO) and adapted to the local setting. Descriptive statistics and regression analyses were used to analyse the data. FINDINGS: The most trusted sources of information included health workers (32.5%) and the ministry of health (23.6 %). Increasing levels of trust in the medical sector were associated with decreasing levels of believing misinformation. Overall, 62.8 % of participants said they would take the COVID-19 vaccine if available. Regression analyses showed those who agreed that everyone should adhere to the national immunization schedule and those who would take the flu vaccine, were 2.77 (95% CI 1.77-4.35) and 4.60 (95% CI 3.11-6.84) timesmore likely to take the vaccine, respectively. INTERPRETATION: Our study found increasing trust in health sources, confidence in medical sector, adherence to the national immunisation schedule and acceptance of the flu vaccine may increase COVID-19 vaccine willingness rates. Although the generalisability of the findings is limited, the results of this exploratory survey may be used to identify areas for prioritisation and improvement in future research.

Outcome of delirium in critically ill patients: systematic review and meta-analysis.

OBJECTIVES: To determine the relation between delirium in critically ill patients and their outcomes in the short term (in the intensive care unit and in hospital) and after discharge from hospital. DESIGN: Systematic review and meta-analysis of published studies. DATA SOURCES: PubMed, Embase, CINAHL, Cochrane Library, and PsychINFO, with no language restrictions, up to 1 January 2015. ELIGIBILITY CRITERIA FOR SELECTION STUDIES: Reports were eligible for inclusion if they were prospective observational cohorts or clinical trials of adults in intensive care units who were assessed with a validated delirium screening or rating system, and if the association was measured between delirium and at least one of four clinical endpoints (death during admission, length of stay, duration of mechanical ventilation, and any outcome after hospital discharge). Studies were excluded if they primarily enrolled patients with a neurological disorder or patients admitted to intensive care after cardiac surgery or organ/tissue transplantation, or centered on sedation management or alcohol or substance withdrawal. Data were extracted on characteristics of studies, populations sampled, identification of delirium, and outcomes. Random effects models and meta-regression analyses were used to pool data from individual studies. RESULTS: Delirium was identified in 5280 of 16,595 (31.8%) critically ill patients reported in 42 studies. When compared with control patients without delirium, patients with delirium had significantly higher mortality during admission (risk ratio 2.19, 94% confidence interval 1.78 to 2.70; P<0.001) as well as longer durations of mechanical ventilation and lengths of stay in the intensive care unit and in hospital (standard mean differences 1.79 (95% confidence interval 0.31 to 3.27; P<0.001), 1.38 (0.99 to 1.77; P<0.001), and 0.97 (0.61 to 1.33; P<0.001), respectively). Available studies indicated an association between delirium and cognitive impairment after discharge. CONCLUSIONS: Nearly a third of patients admitted to an intensive care unit develop delirium, and these patients are at increased risk of dying during admission, longer stays in hospital, and cognitive impairment after discharge.

Zebrafish yolk-specific not really started (nrs) gene is a vertebrate homolog of the Drosophila spinster gene and is essential for embryogenesis.

By using retroviral insertional mutagenesis in zebrafish, we have identified a recessive lethal mutation in the not really started (nrs) gene. The nrs mutation disrupts a gene located in linkage group 3 that is highly homologous to the spinster gene identified in Drosophila and to spinster orthologs identified in mammals. In flies, spinster encodes a membrane protein involved in lysosomal metabolism and programmed cell death in the central nervous system and in the ovary. In nrs mutant fish embryos, we detect an opaque substance in the posterior yolk cell extension at approximately 1 day after fertilization. This material progressively accumulates and by 48 hr after fertilization fills the entire yolk. By day 3 of embryogenesis, mutant embryos are severely reduced in size compared with their wild-type siblings and they die a few hours later. By in situ hybridization, we show that the nrs mRNA is expressed in the yolk cell at the time the mutant phenotype becomes apparent. In wild-type embryos, nrs message is present maternally and zygotically throughout embryogenesis and is also detected in adult animals. In nrs homozygous mutant embryos, nrs transcripts are undetectable at the time the phenotype becomes apparent, indicating that the retroviral insertion has most likely abolished expression of the nrs gene. Finally, the nrs phenotype can be partially rescued by microinjection of nrs encoding DNA. These results suggest that the nrs mutation affects an essential gene encoding a putative membrane-bound protein expressed specifically in the yolk cell during zebrafish embryogenesis.