Functional and biochemical characterisation of remote homologues of type IV pili proteins PilN and PilO in Helicobacter pylori.

Helicobacter pylori encodes homologues of PilM, PilN and PilO from bacteria with Type IV pili, where these proteins form a pilus alignment complex. Inactivation of pilO changes H. pylori motility in semi-solid media, suggesting a link to the chemosensory pathways or flagellar motor. Here, we showed that mutation of the pilO or pilN gene in H. pylori strain SS1 reduced the mean linear swimming speed in liquid media, implicating PilO and PilN in the function, or regulation of, the flagellar motor. We also demonstrated that the soluble variants of H. pylori PilN and PilO share common biochemical properties with their Type IV pili counterparts which suggests their adapted function in the bacterial flagellar motor may be similar to that in the Type IV pili.

O-glycosylation of intrinsically disordered regions regulates homeostasis of membrane proteins in streptococci.

Proteins harboring intrinsically disordered regions (IDRs) lacking stable secondary or tertiary structures are abundant across the three domains of life. These regions have not been systematically studied in prokaryotes. Our genome-wide analysis identifies extracytoplasmic serine/threonine-rich IDRs in several biologically important membrane proteins in streptococci. We demonstrate that these IDRs are O-glycosylated with glucose by glycosyltransferases GtrB and PgtC2 in Streptococcus pyogenes and Streptococcus pneumoniae, and with N-acetylgalactosamine by a Pgf-dependent mechanism in Streptococcus mutans. Absence of glycosylation leads to a defect in biofilm formation under ethanol-stressed conditions in S. mutans. We link this phenotype to the C-terminal IDR of a post-translocation secretion chaperone PrsA. O-glycosylation of the IDR protects this region from proteolytic degradation. The IDR length attenuates the efficiency of glycosylation and, consequently, the expression level of PrsA. Taken together, our data reveal that O-glycosylation of IDRs functions as a dynamic switch of protein homeostasis in streptococci.

Cysteine and resistance to oxidative stress: implications for virulence and antibiotic resistance.

Reactive oxygen species (ROS), including the superoxide radical anion (O2•-), hydrogen peroxide (H2O2), and the hydroxyl radical (•HO), are inherent components of bacterial metabolism in an aerobic environment. Bacteria also encounter exogenous ROS, such as those produced by the host cells during the respiratory burst. As ROS have the capacity to damage bacterial DNA, proteins, and lipids, detoxification of ROS is critical for bacterial survival. It has been recently recognised that low-molecular-weight (LMW) thiols play a central role in this process. Here, we review the emerging role of cysteine in bacterial resistance to ROS with a link to broader elements of bacterial lifestyle closely associated with cysteine-mediated oxidative stress response, including virulence and antibiotic resistance.

Pal power: Demonstration of the functional association of the Helicobacter pylori flagellar motor with peptidoglycan-associated lipoprotein (Pal) and its preliminary crystallographic analysis.

The bacterial flagellar motor is a molecular nanomachine, the assembly and regulation of which requires many accessory proteins. Their identity, structure and function are often discovered through characterisation of mutants with impaired motility. Here, we demonstrate the functional association of the Helicobacter pylori peptidoglycan-associated lipoprotein (HpPal) with the flagellar motor by analysing the motility phenotype of the ∆pal mutant, and present the results of the preliminary X-ray crystallographic analysis of its globular C-terminal domain HpPal-C. Purified HpPal-C behaved as a dimer in solution. Crystals of HpPal-C were grown by the hanging drop vapour diffusion method using medium molecular weight polyethylene glycol (PEG) Smear as the precipitating agent. The crystals belong to the primitive orthorhombic space group P1 with unit cell parameters a = 50.7, b = 63.0, c = 75.1 Å. X-ray diffraction data were collected to 1.8 Å resolution on the Australian Synchrotron beamline MX2. Calculation of the Matthews coefficient (VM=2.24 Å3/Da) and molecular replacement showed that the asymmetric unit contains two protein subunits. This study is an important step towards elucidation of the non-canonical role of H. pylori Pal in the regulation, or function of, the flagellar motor.

Characterization of a New, Country Bean (Lablab purpureus) Lineage of Bean Common Mosaic Necrosis Virus.

Country bean (Lablab purpureus, family Fabaceae) is grown in subsistence agriculture in Bangladesh as a multipurpose crop for food, animal feed, and green manure. This study was undertaken to investigate the genetic diversity of bean common mosaic necrosis virus (BCMNV, genus Potyvirus, family Potyviridae) in country beans. Leaf samples from country beans showing yellowing, vein banding, and mosaic symptoms were collected during field surveys between 2015 and 2019 cropping seasons from farmers' fields in different geographic regions. These samples were tested by serological and molecular diagnostic assays for the presence of BCMNV. Virus-positive samples were subjected to high-throughput Illumina sequencing to generate near-complete genomes of BCMNV isolates. In pairwise comparisons, the polyprotein sequences of BCMNV isolates from Bangladesh showed greater than 98% identities among themselves and shared less than 84% sequence identity at the nucleotide level with virus isolates reported from other countries. In the phylogenetic analysis, BCMNV isolates from Bangladeshi country beans formed a separate clade from virus isolates reported from common beans in other countries in the Americas, Africa, Europe, and from East Timor. Grow-out studies showed seed-to-seedling transmission of BCMNV, implying a possible seedborne nature of the virus in country beans.

Efficacy of Lemon Myrtle Essential Oil as a Bio-Fungicide in Inhibiting Citrus Green Mould.

The effectiveness of lemon myrtle (LM) (Backhousia citriodora) essential oil (EO) was investigated to combat Penicillium digitatum by in vitro agar diffusion and vapour assay and in artificially infected oranges. The main constituent of LM EO was revealed as citral when analysed in gas chromatography-mass spectrometry. Pure citral was also included in the experiment for comparison. The in vitro fungal growth was significantly inhibited by LM EO at 1, 2, 3, 4 and 5 µL per disc while complete growth inhibition by both the pure citral and LM EO occurred at 4 and 5 µL per disc. Inoculated fruits treated by dipping in 1000 µL L-1 LM EO solutions for 5, 10, 15, 30 and 120 s showed significantly lower fungal wounds compared to control. While longer dipping times led to some rind injuries, fruits with a 5 and 10 s dip were found free from any injury. The evaluation after dipping and storage confirmed that the fruits maintained the sensory attributes and were not compromised by the incorporation of the essential oil. The results of this study indicate that LM EO can be a promising alternative to synthetic fungicides for preserving the quality of citrus fruits during storage.

Effects of cumulative COVID-19 cases on mental health: Evidence from multi-country survey.

BACKGROUND: Depression and anxiety were both ranked among the top 25 leading causes of global burden of diseases in 2019 prior to the coronavirus disease 2019 (COVID-19) pandemic. The pandemic affected, and in many cases threatened, the health and lives of millions of people across the globe and within the first year, global prevalence of anxiety and depression increased by 25% with the greatest influx in places highly affected by COVID-19. AIM: To explore the psychological impact of the pandemic and resultant restrictions in different countries using an opportunistic sample and online questionnaire in different phases of the pandemic. METHODS: A repeated, cross-sectional online international survey of adults, 16 years and above, was carried out in 10 countries (United Kingdom, India, Canada, Bangladesh, Ukraine, Hong Kong, Pakistan, Egypt, Bahrain, Saudi Arabia). The online questionnaire was based on published approaches to understand the psychological impact of COVID-19 and the resultant restrictions. Five standardised measures were included to explore levels of depression [patient health questionnaire (PHQ-9)], anxiety [generalized anxiety disorder (GAD) assessment], impact of trauma [the impact of events scale-revised (IES-R)], loneliness (a brief loneliness scale), and social support (The Multi-dimensional Scale of Perceived Social support). RESULTS: There were two rounds of the online survey in 10 countries with 42866 participants in Round 1 and 92260 in Round 2. The largest number of participants recruited from the United Kingdom (112985 overall). The majority of participants reported receiving no support from mental health services throughout the pandemic. This study found that the daily cumulative COVID-19 cases had a statistically significant effect on PHQ-9, GAD-7, and IES-R scores. These scores significantly increased in the second round of surveys with the ordinary least squares regression results with regression discontinuity design specification (to control lockdown effects) confirming these results. The study findings imply that participants' mental health worsened with high cumulative COVID-19 cases. CONCLUSION: Whist we are still living through the impact of COVID-19, this paper focuses on its impact on mental health, discusses the possible consequences and future implications. This study revealed that daily cumulative COVID-19 cases have a significant impact on depression, anxiety, and trauma. Increasing cumulative cases influenced and impacted education, employment, socialization and finances, to name but a few. Building a database of global evidence will allow for future planning of pandemics, particularly the impact on mental health of populations considering the cultural differences.

The Caenorhabditis elegans cullin-RING ubiquitin ligase CRL4DCAF-1 is required for proper germline nucleolus morphology and male development.

Cullin-RING ubiquitin ligases (CRLs) are the largest class of ubiquitin ligases with diverse functions encompassing hundreds of cellular processes. Inactivation of core components of the CRL4 ubiquitin ligase produces a germ cell defect in Caenorhabditis elegans that is marked by abnormal globular morphology of the nucleolus and fewer germ cells. We identified DDB1 Cullin4 associated factor (DCAF)-1 as the CRL4 substrate receptor that ensures proper germ cell nucleolus morphology. We demonstrate that the dcaf-1 gene is the ncl-2 (abnormal nucleoli) gene, whose molecular identity was not previously known. We also observed that CRL4DCAF-1 is required for male tail development. Additionally, the inactivation of CRL4DCAF-1 results in a male-specific lethality in which a percentage of male progeny arrest as embryos or larvae. Analysis of the germ cell nucleolus defect using transmission electron microscopy revealed that dcaf-1 mutant germ cells possess significantly fewer ribosomes, suggesting a defect in ribosome biogenesis. We discovered that inactivation of the sperm-fate specification gene fog-1 (feminization of the germ line-1) or its protein-interacting partner, fog-3, rescues the dcaf-1 nucleolus morphology defect. Epitope-tagged versions of both FOG-1 and FOG-3 proteins are aberrantly present in adult dcaf-1(RNAi) animals, suggesting that DCAF-1 negatively regulates FOG-1 and FOG-3 expression. Murine CRL4DCAF-1 targets the degradation of the ribosome assembly factor periodic trptophan protein 1 (PWP1). We observed that the inactivation of Caenorhabditis elegansDCAF-1 increases the nucleolar levels of PWP1 in the germ line, intestine, and hypodermis. Reducing the level of PWP-1 rescues the dcaf-1 mutant defects of fewer germ cell numbers and abnormal nucleolus morphology, suggesting that the increase in PWP-1 levels contributes to the dcaf-1 germline defect. Our results suggest that CRL4DCAF-1 has an evolutionarily ancient role in regulating ribosome biogenesis including a conserved target in PWP1.

Molecular Recognition of Methacryllysine and Crotonyllysine by the AF9 YEATS Domain.

Histone lysine methacrylation and crotonylation are epigenetic marks that play important roles in human gene regulation. Here, we explore the molecular recognition of histone H3 peptides possessing methacryllysine and crotonyllysine at positions 18 and 9 (H3K18 and H3K9) by the AF9 YEATS domain. Our binding studies demonstrate that the AF9 YEATS domain displays a higher binding affinity for histones possessing crotonyllysine than the isomeric methacryllysine, indicating that AF9 YEATS distinguishes between the two regioisomers. Molecular dynamics simulations reveal that the crotonyllysine/methacryllysine-mediated desolvation of the AF9 YEATS domain provides an important contribution to the recognition of both epigenetic marks. These results provide important knowledge for the development of AF9 YEATS inhibitors, an area of biomedical interest.

Association of DNA Promoter Methylation and BRAF Mutation in Thyroid Cancer.

The BRAF V600E mutation and DNA promoter methylation play important roles in the pathogenesis of thyroid cancer (TC). However, the association of these genetic and epigenetic alterations is not clear. In this study, using paired tumor and surrounding normal tissue from the same patients, on a genome-wide scale we tried to identify (a) any association between BRAF mutation and DNA promoter methylation, and (b) if the molecular findings may provide a basis for therapeutic intervention. We included 40 patients with TC (female = 28, male = 12) without distant metastasis. BRAF mutation was present in 18 cases. We identified groups of differentially methylated loci (DML) that are found in (a) both BRAF mutant and wild type, (b) only in BRAF mutant tumors, and (c) only in BRAF wild type. BRAF mutation-specific promoter loci were more frequently hypomethylated, whereas BRAF wild-type-specific loci were more frequently hypermethylated. Common DML were enriched in cancer-related pathways, including the mismatch repair pathway and Wnt-signaling pathway. Wild-type-specific DML were enriched in RAS signaling. Methylation status of checkpoint signaling genes, as well as the T-cell inflamed genes, indicated an opportunity for the potential use of PDL1 inhibitors in BRAF mutant TC. Our study shows an association between BRAF mutation and methylation in TC that may have biological significance.

Extragenital Sexually Transmitted Infection Testing Among Louisiana Parish Health Units, 2016-2019.

BACKGROUND: The Centers for Disease Control and Prevention recommends that men who have sex with men (MSM) get tested annually for urethral and rectal chlamydia (CT) and gonorrhea (NG), and pharyngeal NG. There are no national recommendations to screen women and heterosexual men at extragenital sites. We assessed extragenital CT/NG screening among men and women at Louisiana's Parish Health Units (PHU). METHODS: The Louisiana STD/HIV/Hepatitis Program piloted extragenital screening at 4 PHUs in February 2016 and expanded to 11 PHUs in 2017. Sexual histories were used to identify gender of sex partners and exposed sites. Because of billing restrictions, up to 2 anatomical sites were tested for CT/NG. RESULTS: From February 2016 to June 2019, 70,895 urogenital and extragenital specimens (56,086 urogenital, 13,797 pharyngeal, and 1,012 rectal) were collected from 56,086 patients. Pharyngeal CT positivity was 160 of 7,868 (2.0%) among women, 54 of 4,838 (1.1%) among men who have sex with women (MSW) and 33 of 1,091 (3.0%) among MSM. Rectal CT positivity was 51 of 439 (11.6%) among women and 95 of 573 (16.6%) among MSM. Pharyngeal NG positivity was 299 of 7,868 (3.8%) among women, 222 of 4,838 (4.6%) among MSW, and 97 of 1,091 (8.9%) among MSM. Rectal NG positivity was 20 of 439 (4.6%) among women and 134 of 573 (23.4%) among MSM.Urogenital-only screening would have missed: among women, 173 of 3,923 (4.4%) CT and 227 of 1,480 (15.3%) NG infections; among MSW, 26 of 2,667 (1%) CT and 149 of 1,709 (8.7%) NG infections; and among MSM, 116 of 336 (34.5%) CT and 127 of 413 (42.1%) NG infections. CONCLUSIONS: Many CT/NG infections would have been missed with urogenital-only screening. Men who have sex with men had much higher extragenital infection rates than women and MSW.

A membrane reticulum, the centriculum, affects centrosome size and function in Caenorhabditis elegans.

Centrosomes are cellular structures that nucleate microtubules. At their core is a pair of centrioles that recruit pericentriolar material (PCM). Although centrosomes are considered membraneless organelles, in many cell types, including human cells, centrosomes are surrounded by endoplasmic reticulum (ER)-derived membranes of unknown structure and function. Using volume electron microscopy (vEM), we show that centrosomes in the Caenorhabditis elegans (C. elegans) early embryo are surrounded by a three-dimensional (3D), ER-derived membrane reticulum that we call the centriculum, for centrosome-associated membrane reticulum. The centriculum is adjacent to the nuclear envelope in interphase and early mitosis and fuses with the fenestrated nuclear membrane at metaphase. Centriculum formation is dependent on the presence of an underlying centrosome and on microtubules. Conversely, increasing centriculum size by genetic means led to the expansion of the PCM, increased microtubule nucleation capacity, and altered spindle width. The effect of the centriculum on centrosome function suggests that in the C. elegans early embryo, the centrosome is not membraneless. Rather, it is encased in a membrane meshwork that affects its properties. We provide evidence that the centriculum serves as a microtubule "filter," preventing the elongation of a subset of microtubules past the centriculum. Finally, we propose that the fusion between the centriculum and the nuclear membrane contributes to nuclear envelope breakdown by coupling spindle elongation to nuclear membrane fenestration.

PplD is a de-N-acetylase of the cell wall linkage unit of streptococcal rhamnopolysaccharides.

The cell wall of the human bacterial pathogen Group A Streptococcus (GAS) consists of peptidoglycan decorated with the Lancefield group A carbohydrate (GAC). GAC is a promising target for the development of GAS vaccines. In this study, employing chemical, compositional, and NMR methods, we show that GAC is attached to peptidoglycan via glucosamine 1-phosphate. This structural feature makes the GAC-peptidoglycan linkage highly sensitive to cleavage by nitrous acid and resistant to mild acid conditions. Using this characteristic of the GAS cell wall, we identify PplD as a protein required for deacetylation of linkage N-acetylglucosamine (GlcNAc). X-ray structural analysis indicates that PplD performs catalysis via a modified acid/base mechanism. Genetic surveys in silico together with functional analysis indicate that PplD homologs deacetylate the polysaccharide linkage in many streptococcal species. We further demonstrate that introduction of positive charges to the cell wall by GlcNAc deacetylation protects GAS against host cationic antimicrobial proteins.

Topical prostaglandin analogue use and cystoid macular oedema following uneventful cataract surgery: a randomised control trial.

BACKGROUND/AIMS: The association between the development of cystoid macular oedema (CMO) following uneventful cataract surgery and prostaglandin analogue (PGA) therapy has not been fully determined. The study aim was to investigate whether discontinuation of PGA therapy following uneventful cataract surgery affected the incidence of postoperative CMO. METHODS: A prospective randomised controlled trial of 62 eyes of 62 participants with ocular hypertension (OH) or primary open angle glaucoma (POAG) treated with PGAs prior to cataract surgery. Participants were randomised to continue with PGA therapy after cataract surgery (CPGA) (n=31) or to discontinue PGA therapy (n=31). The primary outcome measure was the development of CMO at 1-month postoperatively, determined by a masked observer assessment of optical coherence tomography scans. The secondary outcome measure was change from baseline intraocular pressure (IOP). RESULTS: The incidence of CMO was identical in both groups at 12.9% (4 of 31 eyes) at the 1-month postoperative visit (OR 1.000; 95% CI 0.227 to 4.415). At 1-month postoperatively, the IOP was significantly lower in the CPGA group compared with baseline IOP. CONCLUSION: Continuation of PGA therapy following uneventful cataract surgery in eyes with normal macular morphology did not increase the incidence of CMO. Continuation of PGA therapy significantly reduced IOP at 1-month postoperatively suggesting that, when indicated, it might be beneficial to continue PGA therapy in patients with POAG or OH after uneventful cataract surgery in the absence of other risk factors for developing CMO.

Electronic Messaging for Gonorrhea and Chlamydia Test Result Notification, Improving Treatment and Patient Satisfaction.

BACKGROUND: Approximately 20% of chlamydia (CT) and gonorrhea (GC) cases in Louisiana are diagnosed at Parish Health Units. Patient notification of CT and GC test results involves nurses' phone calls and letters to positive patients, which is time-consuming and inefficient. METHODS: In December 2018, electronic results notification was implemented in Caddo Parish Health Unit using Chexout software to notify enrolled patients via text or email when test results are ready to view in a patient portal. We compared the timeliness of GC/CT results notification and treatment pre-Chexout (December 2017 to November 2018) and post-Chexout (December 2018 to November 2019) implementation. A random sample of patients was interviewed to assess acceptability. RESULTS: During December 2018 to November 2019, 5432 patients were tested for CT/GC, 3924 (72%) enrolled in Chexout, and notifications were sent to 3884 (99%). Among CT-positives, 472 of 568 (83%) viewed results in the portal compared with 2451 of 3356 (73%) CT-negatives. Among GC-positives, 300 of 353 (85%) viewed results compared with 2657 of 3571 (74%) GC-negatives. Treatment success for CT improved from 493 of 670 (74%) to 506 of 568 (89%), and for GC, from 332 of 409 (81%) to 325 of 353 (92%). Mean time to treatment decreased for CT (13.4-10.7 days) and GC (11.3-9.2 days). Enrolled patients found Chexout notification satisfactory in 168 of 169 (99%) and easy to use in 130 of 141 (92%). Reasons for declining electronic notification included lack of personal cell phone for 55 of 86 (64%) and confidentiality concerns for 42 of 86 (49%). CONCLUSIONS: Electronic messaging decreased time to notification and increased treatment success. Nurses spent less time notifying patients leaving more time for patient care.

An RNAi screen for genes that affect nuclear morphology in Caenorhabditis elegans reveals the involvement of unexpected processes.

Aberration in nuclear morphology is one of the hallmarks of cellular transformation. However, the processes that, when mis-regulated, result aberrant nuclear morphology are poorly understood. In this study, we carried out a systematic, high-throughput RNAi screen for genes that affect nuclear morphology in Caenorhabditis elegans embryos. The screen employed over 1700 RNAi constructs against genes required for embryonic viability. Nuclei of early embryos are typically spherical, and their NPCs are evenly distributed. The screen was performed on early embryos expressing a fluorescently tagged component of the nuclear pore complex (NPC), allowing visualization of nuclear shape as well as the distribution of NPCs around the nuclear envelope. Our screen uncovered 182 genes whose downregulation resulted in one or more abnormal nuclear phenotypes, including multiple nuclei, micronuclei, abnormal nuclear shape, anaphase bridges, and abnormal NPC distribution. Many of these genes fall into common functional groups, including some that were not previously known to affect nuclear morphology, such as genes involved in mitochondrial function, the vacuolar ATPase, and the CCT chaperonin complex. The results of this screen add to our growing knowledge of processes that affect nuclear morphology and that may be altered in cancer cells that exhibit abnormal nuclear shape.

Repeat Syphilis Among HIV-Infected Men in Florida and Louisiana 2000-2018: Implications for Screening Recommendations.

Syphilis rates have continued to rise in the United States. Florida and Louisiana consistently report high numbers of cases. We evaluated rates of reinfection to see if frequent rescreening might lead to earlier treatment and prevent infections. All syphilis records of all stages for males and females aged 15-70 years from the Florida and Louisiana Departments of Health surveillance databases 2000-2018 were evaluated. The first episode of syphilis during this period was considered the initial diagnosis for each person. Demographics of cases and repeaters (individuals reported with two or more cases of syphilis) were examined. Percentages of syphilis cases from repeaters by year were calculated as were percentages from HIV+ males. During 2000-2018, 124,827 syphilis cases were reported from 107,405 individuals: 73,811 (68.7%) males; 33,594 (31.3%) females. There were 12,545 individuals (repeaters) with two or more syphilis diagnoses (n = 17,422 cases; range, 2-10). From 2010 to 2018, repeaters accounted for steadily increasing percentage of all syphilis reported: 2010 (11%), 2013 (16%), 2015 (20%), and 2018 (26%). Among HIV+ male cases the percentage from repeaters also increased: 2010 (28%), 2013 (35%), 2015 (42%), and 2018 (50%). In 2018, 19% of all cases (n = 2455) were from HIV+ males who had a previous syphilis diagnosis. Among HIV+ males diagnosed with syphilis in 2015, 34% had a repeat syphilis diagnosis within 3 years. Most syphilis diagnosed in Florida and Louisiana was among persons infected for the first time. However, some subgroups could possibly benefit from more frequent screening. Males living with HIV who had a prior syphilis diagnosis were at very high risk of repeat infection.

A Workflow for High-pressure Freezing and Freeze Substitution of the Caenorhabditis elegans Embryo for Ultrastructural Analysis by Conventional and Volume Electron Microscopy.

The free-living nematode Caenorhabditis elegans is a popular model system for studying developmental biology. Here we describe a detailed protocol to high-pressure freeze the C. elegans embryo (either ex vivo after dissection, or within the intact worm) followed by quick freeze substitution. Processed samples are suitable for ultrastructural analysis by conventional electron microscopy (EM) or newer volume EM (vEM) approaches such as Focused Ion Beam Scanning Electron Microscopy (FIB-SEM). The ultrastructure of cellular features such as the nuclear envelope, chromosomes, endoplasmic reticulum and mitochondria are well preserved after these experimental procedures and yield accurate 3D models for visualization and analysis ( Chang et al., 2020 ). This protocol was used in the 3D reconstruction of membranes and chromosomes after pronuclear meeting in the C. elegans zygote ( Rahman et al., 2020 ).

Bioinformatics analysis and biochemical characterisation of ABC transporter-associated periplasmic substrate-binding proteins ModA and MetQ from Helicobacter pylori strain SS1.

The human gastric pathogen Helicobacter pylori relies on the uptake of host-provided nutrients for its proliferation and pathogenicity. ABC transporters that mediate import of small molecules into the cytoplasm of H. pylori employ their cognate periplasmic substrate-binding proteins (SBPs) for ligand capture in the periplasm. The genome of the mouse-adapted strain SS1 of H. pylori encodes eight ABC transporter-associated SBPs, but little is known about their specificity or structure. In this study, we demonstrated that the SBP annotated as ModA binds molybdate (MoO42-, KD = 3.8 nM) and tungstate (WO42-, KD = 7.8 nM). In addition, we showed that MetQ binds D-methionine (KD = 9.5 µM), but not L-methionine, which suggests the existence of as yet unknown pathway for L-methionine uptake. Homology modelling has led to identification of the ligand-binding residues.

Hepatitis E virus genotype 1f outbreak in Bangladesh, 2018.

Hepatitis E virus (HEV) infection is a significant public health issue in many developing countries, causing waterborne outbreaks as well as sporadic hepatitis. We report here an outbreak of HEV genotype 1f infection during April-May 2018 among people living at Halisohor, a low land in the southern part of Chottogram District of Bangladesh. A total of 933 patients were admitted to Combined Military Hospital (CMH), Chottogram, with symptoms of acute hepatitis. Among them, 550 patients were tested by ELISA for HEV-specific (IgM) and all were positive. Genotyping, sequencing, and phylogenetic analysis based on ORF2 region revealed that the outbreak was caused by genotype 1f and the strains were closely related to the previously reported HEV strains that caused the outbreak in Bangladesh in 2010. The current outbreak was most likely linked with water supply as fecal contamination in water was evident and could be prevented by ensuring access to safe drinking water.