Significant Loss Research Articles

Ability of a dynamical climate sensitive disease model to reproduce historical Rift Valley Fever outbreaks over Africa

Rift Valley Fever (RVF) is a zoonosis transmitted by Aedes and Culex mosquitoes, and is considered a priority pathogen by the WHO. RVF epidemics mostly occur in Africa and can decimate livestock herds, causing significant economic losses and posing health risks for humans. RVF transmission is associated with the occurrence of El Niño events that cause floods in eastern Africa and favour the emergence of mosquitoes in wetlands. Different risk models have been developed to forecast RVF transmission risk but very few studies have validated models at pan-African scale. This study aims to validate the skill of the Liverpool Rift Valley Fever model (LRVF) in reproducing RVF epidemics over Africa and to explore the relationship between simulated climatic suitability for RVF transmission and large-scale climate modes of variability such as the El Niño Southern Oscillation (ENSO) and the Dipole Mode Index (DMI). Our results show that the LRVF model correctly simulates RVF transmission hotspots and reproduces large epidemics that affected African countries. LRVF was able to correctly reproduce major RVF epidemics in Somalia, Kenya, Zambia and to a lesser extent for Mauritania and Senegal. The positive phases of ENSO and DMI are associated with an increased risk of RVF over the Horn of Africa, with important time lags. Following research activities should focus on the development of predictive modelling systems at different time scales.

Identification of Potentially Repurposable Drugs for Lewy Body Dementia Using a Network-Based Approach.

The conventional method of one drug being used for one target has not yielded therapeutic solutions for Lewy body dementia (LBD), which is a leading progressive neurological disorder characterized by significant loss of neurons. The age-related disease is marked by memory loss, hallucinations, sleep disorder, mental health deterioration, palsy, and cognitive impairment, all of which have no known effective cure. The present study deploys a network medicine pipeline to repurpose drugs having considerable effect on the genes and proteins related to the diseases of interest. We utilized the novel SAveRUNNER algorithm to quantify the proximity of all drugs obtained from DrugBank with the disease associated gene dataset obtained from Phenopedia and targets in the human interactome. We found that most of the 154 FDA-approved drugs predicted by SAveRUNNER were used to treat nervous system disorders, but some off-label drugs like quinapril and selegiline were interestingly used to treat hypertension and Parkinson's disease (PD), respectively. Additionally, we performed gene set enrichment analysis using Connectivity Map (CMap) and pathway enrichment analysis using EnrichR to validate the efficacy of the drug candidates obtained from the pipeline approach. The investigation enabled us to identify the significant role of the synaptic vesicle pathway in our disease and accordingly finalize 8 suitable antidepressant drugs from the 154 drugs initially predicted by SAveRUNNER. These potential anti-LBD drugs are either selective or non-selective inhibitors of serotonin, dopamine, and norepinephrine transporters. The validated selective serotonin and norepinephrine inhibitors like milnacipran, protriptyline, and venlafaxine are predicted to manage LBD along with the affecting symptomatic issues.

The identification of small molecule inhibitors with anthelmintic activities that target conserved proteins among ruminant gastrointestinal nematodes.

Gastrointestinal nematode (GIN) infections are a major concern for the ruminant industry worldwide and result in significant production losses. Naturally occurring polyparasitism and increasing drug resistance that potentiate disease outcomes are observed among the most prevalent GINs of veterinary importance. Within the five major taxonomic clades, clade Va represents a group of GINs that predominantly affect the abomasum or small intestine of ruminants. However, the development of effective broad-spectrum anthelmintics against ruminant clade Va GINs has been challenged by a lack of comprehensive druggable genome resources. Here, we first assembled draft genomes for three clade Va species (Cooperia oncophora, Trichostrongylus colubriformis, and Ostertagia ostertagi) and compared them with closely related ruminant GINs. Genome-wide phylogenetic reconstruction showed a relationship among ruminant GINs structured by taxonomic classification. Orthogroup (OG) inference and functional enrichment analyses identified 220 clade Va-specific and Va-conserved OGs, enriched for functions related to cell cycle and cellular senescence. Further transcriptomic analysis identified 61 taxonomically and functionally conserved clade Va OGs that may function as drug targets for new broad-spectrum anthelmintics. Chemogenomic screening identified 11 compounds targeting homologs of these OGs, thus having potential anthelmintic activity. In in vitro phenotypic assays, three kinase inhibitors (digitoxigenin, K-252a, and staurosporine) exhibited broad-spectrum anthelmintic activities against clade Va GINs by obstructing the motility of exsheathed L3 (xL3) or molting of xL3 to L4. These results demonstrate valuable applications of the new ruminant GIN genomes in gaining better insights into their life cycles and offer a contemporary approach to discovering the next generation of anthelmintics.IMPORTANCEGastrointestinal nematode (GIN) infections in ruminants are caused by parasites that inhibit normal function in the digestive tract of cattle, sheep, and goats, thereby causing morbidity and mortality. Coinfection and increasing drug resistance to current therapeutic agents will continue to worsen disease outcomes and impose significant production losses on domestic livestock producers worldwide. In combination with ongoing therapeutic efforts, advancing the discovery of new drugs with novel modes of action is critical for better controlling GIN infections. The significance of this study is in assembling and characterizing new GIN genomes of Cooperia oncophora, Ostertagia ostertagi, and Trichostrongylus colubriformis for facilitating a multi-omics approach to identify novel, biologically conserved drug targets for five major GINs of veterinary importance. With this information, we were then able to demonstrate the potential of commercially available compounds as new anthelmintics.

Role of endoscopic duodenojejunal bypass liner in obesity management and glycemic control.

The treatment of obesity and its comorbidities ranges from clinical management involving lifestyle changes and medications to bariat-ric and metabolic surgery. Various endoscopic bariatric and metabolic therapies recently emerged to address an important therapeutic gap by offering a less invasive alternative to surgery that is more effective than conservative therapies. This article compre-hensively reviews the technical aspects, mechanism of action, outcomes, and future perspectives of one of the most promising endoscopic bariatric and metabolic therapies, named duodenojejunal bypass liner. The duodenojejunal bypass liner mimics the mechanism of Roux-en-Y gastric bypass by preventing food contact with the duodenum and proximal jejunum, thereby initiating a series of hormonal changes that lead to delayed gastric emptying and malabsorptive effects. These physiological changes result in significant weight loss and improved metabolic control, leading to better glycemic levels, preventing dyslipidemia and non-alcoholic fatty liver disease, and mitigating cardiovascular risk. However, concern ex-ists regarding the safety profile of this device due to the reported high rates of severe adverse events, particularly liver abscesses. Ongo-ing technical changes aiming to reduce adverse events are being evaluated in clinical trials and may provide more reliable data to sup-port its routine use in clinical practice.

Genetic characterization of new source of resistance for tomato leaf curl New Delhi virus (ToLCNDV) from snapmelon (C. melo var. momordica)

AbstractThis study aimed to understand the genetics of tomato leaf curl New Delhi virus (ToLCNDV) in the identified novel source of resistance from Indian melon germplasm DSM-19 (Cucumis melo var. momordica) as viral diseases in muskmelon cause significant economic yield loss. To achieve this, a cross was made between the highly susceptible genotype Pusa Sarda (C. melo var. inodorus), known for its desirable fruit characters, and the resistant source DSM-19 to generate the suitable populations for inheritance study. These populations were screened under natural epiphytotic conditions and further validated through challenge inoculation with viruliferous whiteflies. The inheritance of ToLCNDV resistance in snapmelon germplasm DSM-19 was identified as monogenic recessive in both the screening methods. Moreover, a cleaved amplified polymorphic sequence (CAPS) marker named ‘CAPS 16 (2)’ was designed near to SNP marker D16 located on chromosome 11 of melon, and it was found to be linked to the ToLCNDV resistance gene in DSM-19. This is the first report on genetics of ToLCNDV resistance in snapmelon germplasm from India. Snapmelon line DSM-19 can be used as a source for fine mapping and introgression of the ToLCNDV resistance into susceptible muskmelon cultivars.

Loop‐mediated isothermal amplification assay: A novel disease diagnostics tool in sweetpotato seed quality assurance

AbstractSweetpotato is an important food crop in global production. However, sweetoptato viruses pose a threat to sustainable agriculture and cause significant economic loss. More than 30 viruses have been reported to date, with sweet potato feathery mottle virus (SPFMV) and sweet potato chlorotic stunt virus (SPCSV) occurring frequently and in combination, causing sweetpotato virus disease. The detection of viruses directly from sweetpotato is still a challenge, and efforts are being made toward this front. Therefore, rapid detection of viruses is critical for effective control. Current diagnostic tests are not sufficiently sensitive to reliably detect viruses directly from sweetpotato and require expensive laboratory equipment and a high level of skilled experience. Loop‐mediated isothermal amplification (LAMP) is sensitive and specific for both DNA/RNA amplification; it is affordable and its characteristics make it potentially suitable for on‐site testing. LAMP assays have been developed for several sweetpotato viruses: SPCSV, SPFMV, and sweet potato leaf curl virus (and related sweepoviruses). Laboratory validation showed a 100% diagnostic sensitivity for all three viruses. The LAMP on‐site testing results were comparable to those of polymerase chain reaction and reverse transcriptase polymerase chain reaction confirmatory laboratory tests. Interlab validation and packaging into affordable kits will ensure high adoption in sub‐Saharan Africa. The LAMP assay can be used for field surveys and monitoring the phytosanitary status of pre‐basic seed production in quarantine or certification program. This guarantees pathogen‐free planting material enters the seed system. We discuss opportunities for LAMP as a diagnostic assay for the rapid detection of sweetpotato viruses and its adoption as a quality control system for planting materials.

Design, synthesis, antibacterial evaluation of isopropylamine linked with different substituted phenol and piperazine novel derivatives.

Xanthomonas oryzae pv. oryzae (Xoo) is often considered one of the most destructive bacterial pathogens causing bacterial leaf blight (BLB), resulting in significant yield and cost losses in rice. In this study, a series of novel derivatives containing the isopropanolamine moiety linked to various substituted phenols and piperazines were designed, synthesized and screened. Antibacterial activity results showed that most compounds had good inhibitory effects on Xoo, among which compound W2 (EC50 = 2.74 μg mL-1) exhibited the most excellent inhibitory activity, and W2 also had a certain curative effect (35.89%) on rice compared to thiodiazole copper (TC) (21.57%). Scanning electron microscopy (SEM) results indicated that compound W2 could cause rupture of the Xoo cell membrane. Subsequently, proteomics and quantitative real-time polymerase chain reaction revealed that compound W2 affected the physiological processes of Xoo and may exert antibacterial activity by targeting the two-component system pathway. Interestingly, W2 upregulated Xoo's methyltransferase to impact on its pathogenicity. The present study offers a promising phenolic-piperazine-sopropanolamine compound as an innovative antibacterial strategy by specifically targeting the two-component system pathway and inducing upregulation of methyltransferase to effectively impact Xoo's pathogenicity. © 2024 Society of Chemical Industry.

A Spatiotemporal Hierarchical Analysis Method for Urban Traffic Congestion Optimization Based on Calculation of Road Carrying Capacity in Spatial Grids

Traffic congestion is a globally widespread problem that causes significant economic losses, delays, and environmental impacts. Monitoring traffic conditions and analyzing congestion factors are the first, challenging steps in optimizing traffic congestion, one of the main causes of which is regional spatiotemporal imbalance. In this article, we propose an improved spatiotemporal hierarchical analysis method whose steps include calculating road carrying capacity based on geospatial data, extracting vehicle information from remote sensing images to reflect instantaneous traffic demand, and analyzing the spatiotemporal matching degree between roads and vehicles in theory and in practice. First, we defined and calculated the ratio of carrying capacity in a regional road network using a nine-cell-grid model composed of nested grids of different sizes. By the conservation law of flow, we determined unbalanced areas in the road network configuration using the ratio of the carrying capacity of the central cell to that of the nine grid cells. Then, we designed a spatiotemporal analysis method for traffic congestion using real-time traffic data as the dependent variables and five selected spatial indicators relative to the spatial grids as the independent variables. The proposed spatiotemporal analysis method was applied to Chengdu, a typical provincial capital city in China. The relationships among regional traffic, impact factors, and spatial heterogeneity were analyzed. The proposed method effectively integrates GIS, remote sensing, and deep learning technologies. It was further demonstrated that our method is reliable and effective and enhances the coordination of congested areas by virtue of a fast calculation speed and an efficient local balance adjustment.

Methods for the Determination of Fire Blight on Pome Fruit Crop Plants in the Western Part of Azerbaijan

Fire blight caused by Erwinia amylovora (Burrill, 1882) Winslow et al., 1920 causes significant production losses in the world’s leading pome fruit crop producing countries. The main route of infection of many fruit crops, including apple and pear trees, is through newly blooming flowers. The bacterium overwinters in the bark tissue along the edges of cankers formed on branches and stems as a result of infection in the previous year and becomes a source of infection in the next year. Determining the prevalence of the disease in areas with a large number of orchards is important from the point of view of disease control. Therefore, the purpose of the work is to study the prevalence of the disease in the Ganja-Dashkesan and Gazakh-Tovuz Economic Regions, as well as the accurate diagnosis of the obtained E. amylovora isolates using classical and molecular methods. For this purpose, trees in the studied apple and pear orchards were examined for the disease, the pathogen was isolated from infected plants, and morphological, biochemical, physiological and molecular analyzes were carried out. Among 36 bacterial isolates obtained from 27 samples of infected plants, Erwinia amylovora was identified in 11 as a result of morphological, biochemical, physiological and molecular tests.

Integrated application of transcriptomics and metabolomics provides insight into the mechanism of Eimeria tenella resistance to maduramycin

Avian coccidiosis, caused by Eimeria parasites, continues to devastate the poultry industry and results in significant economic losses. Ionophore coccidiostats, such as maduramycin and monensin, are widely used for prophylaxis of coccidiosis in poultry. Nevertheless, their efficacy has been challenged by widespread drug resistance. However, the underlying mechanisms have not been revealed. Understanding the targets and resistance mechanisms to anticoccidials is critical to combat this major parasitic disease. In the present study, maduramycin-resistant (MRR) and drug-sensitive (DS) sporozoites of Eimeria tenella were purified for transcriptomic and metabolomic analysis. The transcriptome analysis revealed 5016 differentially expressed genes (DEGs) in MRR compared to DS, and KEGG pathway enrichment analysis indicated that DEGs were involved in spliceosome, carbon metabolism, glycolysis, and biosynthesis of amino acids. In the untargeted metabolomics assay, 297 differentially expressed metabolites (DEMs) were identified in MRR compared to DS, and KEGG pathway enrichment analysis indicated that these DEMs were involved in 10 pathways, including fructose and mannose metabolism, cysteine and methionine metabolism, arginine and proline metabolism, and glutathione metabolism. Targeted metabolomic analysis revealed 14 DEMs in MRR compared to DS, and KEGG pathway analysis indicated that these DEMs were involved in 20 pathways, including fructose and mannose metabolism, glycolysis/gluconeogenesis, and carbon metabolism. Compared to DS, energy homeostasis and amino acid metabolism were differentially regulated in MRR. Our results provide gene and metabolite expression landscapes of E. tenella following maduramycin induction. This study is the first work involving integrated transcriptomic and metabolomic analyses to identify the key pathways to understand the molecular and metabolic mechanisms underlying drug resistance to polyether ionophores in coccidia.

Shrub Age and Water Dynamics Influence Primary Production, Carbon, and Nitrogen Stocks in a Coastal Environment

Drivers of shrub primary production and associated landscape impacts of encroachment are well known in drylands but have not been thoroughly studied in mesic and coastal habitats. The native, nitrogen-fixing shrub, Morella cerifera, has expanded into coastal grassland along the US Atlantic coast due to warming temperatures, but impacts on ecosystem function are not well known. Annual net primary production (ANPP) of Morella cerifera and key environmental drivers were measured long-term (1990 – 2007) across a chronosequence of shrub age on a mid-Atlantic barrier island. Soil and groundwater nutrients were compared with un-encroached grassland soil to evaluate impacts of vegetation on nutrient dynamics. Shrub ANPP declined with age at the same rate among all thickets, but there was variability from year to year. When climate variables were included in models, shrub age, precipitation, and freshwater table depth were consistent predictors of ANPP. Water table depth decreased over time, reducing ANPP. This may be due to rising sea-level, as well as to feedbacks with shrub age and evapotranspiration. Soil N and C increased with shrub age and were higher than adjacent grassland sites; however, there was a significant loss of N and C to groundwater. Our results demonstrate that drivers influencing the encroachment of shrubs in this coastal system (i.e., warming temperature) are not as important in predicting shrub primary production. Rather, interactions between shrub age and hydrological properties impact ANPP, contributing to coastal carbon storage.

Moving Beyond Boundaries: Utilization of Longitudinal Exposure-Response Model for Bounded Outcome Score to Inform Decision Making in the Accelerated Drug Development Paradigm.

As drug development scientists strive to accelerate availability of therapies for patients, model-informed drug development (MIDD) plays an important role in contextualizing existing information and facilitating decision making. This paper describes an example of MIDD, where modeling and simulation informed decision making in the circumstance of a combined phase 2b and single pivotal study for ritlecitinib (JAK3/TEC family kinases inhibitor). Longitudinal exposure-response (ER) modeling was conducted to describe ritlecitinib efficacy in alopecia areata patients. The Severity of Alopecia Tool (SALT) score (a continuous bounded outcome [CBO] score [0-100]) was used as the efficacy response. The average concentration during the time interval between two adjacent SALT scores was used as the exposure metric driving efficacy. The developed model well described the longitudinal SALT profile of ritlecitinib as well as the frequency of boundary data. The CBO model indicated tested doses in the phase 2b/3 clinical trial are in the ascending region of ER and contextualized a loading dose effect that impacted onset of efficacy without long-term benefit. It also identified disease severity as the only covariate impacting efficacy. The model-based simulation further informed impact of treatment interruption on the loss of efficacy in the absence of a dedicated treatment withdrawal study. Results indicated temporary treatment interruption ≤ 6 weeks is not expected to result in significant loss of efficacy. The CBO modeling approach and simulation supported the single pivotal trial strategy and guided dose selection in the accelerated drug development program of ritlecitinib, which can be applied to many indications where efficacy is measured on a bounded scale.

Innovative use of sensor technology to study grazing behaviour and its associations with parasitic resistance in sheep

Gastrointestinal nematodes (GINs) are a concern for sheep production and are associated with significant economic losses globally, driving the need for effective management strategies. The aims of this research were first to determine the influence of GIN infections on sheep grazing behaviours, specifically grazing time (GT) and grazing event length (GL), and then to estimate the genetic and phenotypic correlation between faecal egg counts (FEC) and salivary specific IgA activity vs GT and GL. Data were collected from 146 Merino sheep on a commercial farm in Victoria, Australia. Faecal, saliva and body weight (BW) were collected at four time points (A: Oct 2019, B: early May 2020, C: late May 2020, and D: Jul 2020), while tri-axial accelerometer sensors recorded GT and GL for the length of 26 days between B and C. Univariate linear regression and Bayesian Generalised Linear Mixed Model, estimated using Markov Chain Monte Carlo, were used to assess the relationships between the behaviours and infection indicators. We found an increase in the logarithm of FEC was associated with a significant rise in grazing time (p < 0.05), suggesting compensatory behaviour in infected sheep. GT also accounted for 6% of the FEC variation. In contrast, the effect of IgA on GT was not significant (p > 0.05). There was a positive genetic and phenotypic correlation estimated between GT and FEC, however, the High Posterior Density interval for the genetic and phenotypic correlations between GT and FEC indicates some uncertainty in these estimates. These results imply that sheep may modify their grazing strategies as an adaptive response to parasitic infections to ease the impact on their nutritional intake. This study improves our understanding of how natural GIN infections affect sheep behaviour and highlights the potential to use animal behaviours as a precision livestock farming tool and in breeding for resilience against parasites.

Genetic Parameter Estimation and Selection for Resistance to Gastrointestinal Nematode Parasites in Sheep-A Review.

Gastrointestinal nematodes (GINs) are a major problem affecting sheep production systems worldwide. The flocks infected with GINs can undergo significant economic losses due to a decrease in productivity, the animals' deaths, and the costs associated with treatments. The over-reliance on anthelmintics in the past years to eliminate GINs has resulted in the development of resistance against the available commercial anthelmintics. Genetically resistant animals can be used in mating systems to improve the overall flock resistance. This review aimed to summarize the estimated genetic parameters for resistance traits and genetic gains through the use of genetic/genomic selection for resistance to GINs in sheep. Heritability estimates from the literature ranged from 0.00 to 0.46 for fecal egg counts, 0.12 to 0.37 for packed cell volume/hematocrit, 0.07 to 0.26 for FAffa MAlan CHArt (FAMACHA©), from 0.10 to 0.37 for blood parameters, and 0.19 for Immunoglobulin A. Genetic correlations between traits measuring resistance to GINs and production traits ranged from negative to positive values in the literature. Genetic gains are possible when genetic/genomic selection for GIN resistance is applied. Therefore, genetic/genomic selection can be used to improve flocks' resistance to GINs as a sustainable approach in sheep production systems.

Clinical prognostic factors predicting survival of motor neuron disease patients with gastrostomy: A retrospective analysis.

Enteral feeding via gastrostomy is a key intervention to prevent significant weight loss in Motor Neuron Disease (MND). The aim of this study was to explore demographic, clinical, and nutritional factors associated with survival time in MND patients with gastrostomy. The retrospective study analyzed 94 MND patients (n = 58 bulbar-onset and n = 36 limb-onset) who underwent gastrostomy between 2015 and 2021. The primary outcome was the survival time from gastrostomy insertion to death. Independent variables of interest explored were: age at gastrostomy insertion, disease onset type, known genetic cause, use of riluzole, non-invasive ventilation (NIV) use, forced vital capacity prior to gastrostomy, weight loss from diagnosis to gastrostomy insertion, and body mass index (BMI) at the time of gastrostomy insertion. The median survival time from gastrostomy to death was 357 days (± 29.3, 95%CI: 299.5, 414.5). Kaplan-Meier method and log-rank test revealed patients with lower body mass index <18.5 kg/m2 at the time of gastrostomy insertion (p = .023) had shorter survival. Cox proportional hazards model with multivariable adjustment revealed that older age (p = .008), and greater weight loss from diagnosis to gastrostomy (p = .003) were associated with shorter survival time post gastrostomy. Limb onset (p = .023), NIV use not being required (p = .008) and daily NIV use when required and tolerated (p = .033) were associated with longer survival. Preventing or minimizing weight loss from MND diagnosis and encouraging NIV use when clinically indicated are modifiable factors that may prolong the survival of MND patients with gastrostomy.

Evaluation of ten bambara groundnut (Vigna subterranean (L.) Verdc.) Accessions to drought stress at Sahelian zone of Niger

Bambara groundnut is a legume mainly cultivated for these seeds in Africa. In the Sahelian zone, it sometimes suffered of significant yield losses linked to drought. The objective of this study is to identify the adapted genotypes to water deficit stress. The experimental design is randomly made up of four complete randomized blocks. Three variants of stress were applied during the growth of the plants, namely a water deficit stress for 14 days, a stress of 10 days and another stress of 7 days and a constantly watered control. The study revealed a systematic decline in yield under water deficit stress conditions in all ten accessions. However, the yields of accessions Ti 049 and Th 113 were the least affected, with decreases of -7.71% and -8.76% respectively compared to the control. However, the Di-3 082 accession recorded the greatest drop in yield (-36.06%). According to the indices determined, it appears that the genotypes Th 113, Ti 047, Ti 049 and Ma-2-65 are the most tolerant to water deficit stress, with considerable yield potential. Accession Di-3 082 was identified as the most sensitive to water deficit stress.

Light at the end of the tunnel: Innovative opportunities for saving tropical biodiversity.

The expansion of roads into wilderness areas and biodiversity hotspots in the Global South seems inevitable and is predicted to bring about significant biodiversity loss. Even so, existing widespread strategies aiming to mitigate the direct and indirect impacts of roads on the environment have been of limited effectiveness. These tactics, including construction of fencing, wildlife crossings on paved roads, and establishment of protected areas along the roads, are unlikely to be sufficient for protecting diverse species assemblages from roadkill, habitat fragmentation, and anthropogenic activity in tropics. This indicates the need for integration of more ambitious approaches into the conservation toolkit, such as the constructing tunnels, covered ways, and elevated roads. Although these tools could significantly support conservation efforts to save tropical biodiversity, to date, they are rarely considered. Here, we discuss factors which determine the need for application of these approaches in the Global South. We highlight the often-overlooked long-term benefits associated with the application of the proposed tools. We also discuss the potential challenges and risks, and the ways to minimise them. Hopefully this article will encourage practitioners to integrate these strategies into conservation toolkits and allow policy-makers and investors to make informed decisions on sustainable road infrastructure development in the Global South.

Impairment of Listeria monocytogenes biofilm developed on industrial surfaces by Latilactobacillus curvatus CRL1579 bacteriocin

The effect of lactocin AL705, bacteriocin produced by Latilactobacillus (Lat.) curvatus CRL1579 against Listeria biofilms on stainless steel (SS) and polytetrafluoroethylene (PTFE) coupons at 10 °C was investigated. L. monocytogenes FBUNT showed the greatest adhesion on both surfaces associated to the hydrophobicity of cell surface. Partially purified bacteriocin (800 UA/mL) effectively inhibited L. monocytogenes preformed biofilm through displacement strategy, reducing the pathogen by 5.54 ± 0.26 and 4.74 ± 0.05 log cycles at 3 and 6 days, respectively. The bacteriocin-producer decreased the pathogen biofilm by ∼2.84 log cycles. Control and Bac− treated samples reached cell counts of 7.05 ± 0.18 and 6.79 ± 0.06 log CFU/cm2 after 6 days of incubation. Confocal scanning laser microscopy (CLSM) allowed visualizing the inhibitory effect of lactocin AL705 on L. monocytogenes preformed biofilms under static and hydrodynamic flow conditions. A greater effect of the bacteriocin was found at 3 days independently of the surface matrix and pathogen growth conditions at 10 °C. As a more realistic approach, biofilm displacement strategy under continuous flow conditions showed a significant loss of biomass, mean thickness and substratum coverage of pathogen biofilm. These findings highlight the anti-biofilm capacity of lactocin AL705 and their potential application in food industries.

Wound pH-Modulating Strategies for Diabetic Wound Healing.

Significance: Chronic diabetic wounds on the lower extremities (diabetic foot ulcers, DFU) are one of the most prevalent and life-threatening complications of diabetes, responsible for significant loss of quality of life and cost to the health care system. Available pharmacologic treatments fail to achieve complete healing in many patients. Recent studies and investigational treatments have highlighted the potential of modulating wound pH in DFU. Recent Advances: Data from in vitro, preclinical, and clinical studies highlight the role of pH in the pathophysiology of DFU, and topical administration of pH-lowering agents have shown promise as a therapeutic strategy for diabetic wounds. In this critical review, we describe the role of pH in DFU pathophysiology and present selected low-molecular-weight and hydrogel-based pH-modulating systems for wound healing and infection control in diabetic wounds. Critical Issues: The molecular mechanisms leading to pH alterations in diabetic wounds are complex and may differ between in vitro models, animal models of diabetes, and the human pathophysiology. Wound pH-lowering bandages for DFU therapy must be tested in established animal models of diabetic wound healing and patients with diabetes to establish a comprehensive benefit-risk profile. Future Directions: As our understanding of the role of pH in the pathophysiology of diabetic wounds is deepening, new treatments for this therapeutic target are being developed and will be tested in preclinical and clinical studies. These therapeutic systems will establish a target product profile for pH-lowering treatments such as an optimal pH profile for each wound healing stage. Thus, controlling wound bed pH could become a powerful tool to accelerate chronic diabetic wound healing.

A171 A MISSENSE MUTATION IN FCGBP, A STRUCTURAL COMPONENT OF MUC2 MUCUS, ALTERS THE GLYCOMICS PROFILE AND FUNCTION OF COLONIC MUCUS

Abstract Background MUC2 mucin produced by colonic goblet cells, form a mucus bilayer that provides a physical barrier between potential pathogens in the lumen and the underlying epithelial cells. Mucus is thus the first line of innate host defense in the gastrointestinal (GI) tract. Many GI diseases including inflammatory bowel disease and colon cancer affect the glycosylation of mucus. Goblet cells produce a variety of proteins that are associated with the mucus layer. Of these proteins, FCGBP is of significant interest due to its structural similarities to MUC2 mucin with unknown functions. In this study, we investigated if a missense mutation in FCGBP altered the glycosylation of goblet cell MUC2 and affected its barrier functions. Aims Aims: 1) To determine mechanistically how FCGBP impeded the structural integrity of the mucus layer 2) To quantify MUC2 glycoprotein modifications in the altered mucus layer Methods To investigate whether FCGBP impaired mucus barrier functions, two cell types were investigated: wildtype LS174T (WT) MUC2 mucus-producing goblet cells and LS174T cells with a missense mutation in FCGBP (FCGBP-Mut). To determine if FCGBP-Mut led to loss in barrier function in the mucus layer, the penetration of 0.2, 1, and 2 μm fluorescent beads (to mimic bacteria) through the mucus layer were quantified. To determine if the differences in penetrability were caused by differences in MUC2 glycosylation in the goblet cell lines, sensitive glycomic analyses were performed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). Both cells and purified MUC2 mucin granules were analyzed and confirmed by lectin binding assays. To enumerate differences in the glycomics profiles, RT-PCR was performed on over 30 human glycosyltransferases. Results FCGBP-Mut cells exhibited an altered glycomics profile with a significant increase in sialylated/fucosylated glycans as quantified by HPLC-MS and an increase in sialyl- and fructosyltransferase mRNA expression. In contrast to WT goblet cells, FCGBP-Mut cells exhibited significant loss in MUC2 mucus barrier function as quantified by fluorescent beads penetration through the mucus layer temporally. The altered glycosylation in FCGBP-Mut cells triggered increased metabolic stress and ROS production that enhanced susceptibility to Salmonella enterica binding, invasion and cell death. Conclusions This study demonstrates that a single missense mutation in FCGBP altered the penetrability of the mucus layer associated with an increase in sialylated/fucosylated glycans, a signature hallmark of numerous colonic diseases. These findings underscore the importance of FCGBP in providing structural integrity of the mucus layer and homeostatic maintenance of goblet cell glycosylation profiles. Funding Agencies CIHR