Search Results (65)

The emergence of multidrug-resistant Shiga toxin-producing Escherichia coli (STEC) poses a major challenge to public health and necessitates the development of alternative antimicrobial strategies. This study aimed to isolate and characterize five lytic bacteriophages belonging to the genus Mosigvirus and evaluate their potential as biocontrol against MDR STEC strains and their biofilms. The five bacteriophages, designated vB_EcoM-pJBB (ΦB), vB_EcoM-pJBC (ΦC), vB_EcoM-pJBJ (ΦJ), vB_EcoM-pJBK (ΦK), and vB_EcoM-pJBL (ΦL), were isolated from sewage treatment plant samples using STEC ATCC 43895 as host. Biological characterization included host range determination against 19 MDR STEC strains, one-step growth analysis, environmental stability assays, bacteriolytic activity assessment, and antibiofilm efficacy testing. Whole-genome sequencing and phylogenetic analyses were performed to determine genomic features and taxonomic classification. The phages demonstrated varying infectious capacities, lysing between six and 12 strains, with ΦL exhibiting the broadest spectrum of activity. All phages showed MOI-independent antibiofilm activity, preventing biofilm formation by approximately 70% and disrupting pre-formed biofilms by up to 80.3%. Genomic analysis revealed the absence of lysogeny markers, virulence factors, and antimicrobial resistance genes, while identifying putative depolymerase genes associated with tail fiber proteins. Phylogenetic analysis confirmed the taxonomic position of these phages within the Mosigvirus genus in the Straboviridae family. Our findings indicate that the newly identified Mosigvirus phages are promising candidates for phage-based biocontrol applications. Full article

Capsular polysaccharides are critical virulence factors of Klebsiella pneumoniae, enabling the bacterium to evade host immune recognition and exacerbate infection. Phage-derived depolymerases, which specifically degrade these capsular polysaccharides, are increasingly recognized as a highly promising strategy for the treatment of bacterial infections. In the present study, we isolated and characterized a lytic Klebsiella pneumoniae phage, named phiTH1, and sequenced its genome. The K30-type capsular polysaccharide was identified as the receptor for phiTH1 infection. A tail fiber protein with a pectate lyase domain, Dop5, was then recognized as a potential K30-type depolymerase. Therefore, the recombinant protein Dop5 was expressed in Escherichia coli and purified, and its in vitro capsular depolymerase activity was demonstrated. Further, by using a murine aspiration pneumonia model induced by K30-type Klebsiella pneumoniae TH1, we found that Dop5 protected 80% of mice from lethal challenge with Klebsiella pneumoniae. After Dop5 treatment, the pathological damage in multiple organs of mice was alleviated, the bacterial load was reduced, and serum levels of inflammatory cytokines and complement C3 decreased, along with a significant reduction in the pathological score of the lungs. Hence, this study revealed the potential of the depolymerase Dop5 for the treatment of Klebsiella pneumoniae infections. Full article

Receptor for advanced glycation end-products (RAGE) activation by hyperglycemia-induced AGE (advanced glycation end-products) accumulation is likely to play a crucial role in the development of complications such as diabetic peripheral neuropathy (DPN). RAGE signaling is mediated via its cytosolic tail. Through its cytosolic tail, RAGE recruits diaphanous-related formin 1 (Diaph1), a protein involved in actin filament organization. Disruption of RAGE–Diaph1 interactions using small molecules alleviates diabetic complications in mice; however, the role of Diaph1 in DPN progression has not been rigorously tested. In this study, we employed a Diaph1 knockout mouse (DKO) to investigate the role of Diaph1 in DPN progression. Herein, we demonstrate that, at the systemic level, CRISPR deletion of Diaph1 fails to ameliorate diabetes-induced weight loss in mice. Within the sciatic nerve (SCN), the lack of Diaph1 failed to prevent hyperglycemia-induced loss of β-actin in the nerve fibers. At a morphological level, the lack of Diaph1 leads to a partial rescue in DPN. While we observed improvements in axonal and fiber diameters in diabetic DKO mice, the g-ratio (an indicator of myelination) and myelin invaginations displayed incomplete rescue. Furthermore, the lack of Diaph1 failed to rescue motor or sensory nerve conduction defects resulting from hyperglycemia over 6 months. Overall, our data thus indicate that the complete loss of Diaph1 is insufficient to halt the progression of DPN. However, across a range of parameters including blood glucose levels, body weight measurements, axon and fiber diameters, and nerve conduction velocity, DKO diabetic mice show improvement when compared to wild-type diabetic mice. Full article

The continued acidification of red soil reduces phosphorus availability and microbial activity, which restricts corn growth. Phosphorus tailings, a waste product from phosphate mining, can neutralize soil acidity and supply controlled-release phosphorus, but their effects on the red soil-corn system remain unclear. A field experiment in Qujing, Yunnan (2023–2024), tested four treatments: CK (standard fertilization), T1 (CK plus phosphorus tailings), T2 (80% of standard fertilizer plus phosphorus tailings), and T3 (80% of standard fertilizer plus phosphorus tailings and organic fertilizer, both applied at 6.0 t·ha⁻¹). Using high-throughput sequencing, redundancy analysis (RDA), and structural equation modeling (SEM), the study evaluated impacts on soil properties, microbial communities, and corn yield and quality. Results showed: (1) Phosphorus tailings reduced soil acidification; T3 raised soil pH in the top 0–10 cm by 0.54–0.9 units compared to CK and increased total, available, and soluble phosphorus in the 0–20 cm layer to 952.82, 28.46, and 2.04 mg/kg, respectively. (2) T3 exhibited the highest microbial diversity (Chao1 and Shannon indices increased by 177.57% and 37.80% versus CK) and a more complex bacterial co-occurrence network (114 edges versus 107 in CK), indicating enhanced breakdown of aromatic compounds. (3) Corn yield under T3 improved by 13.72% over CK, with increases in hundred-grain weight (+6.02%), protein content (+18.04%), and crude fiber (+9.00%). (4) Effective nitrogen, ammonium nitrogen, available phosphorus, and soil conductivity were key factors affecting gcd/phoD phosphorus-reducing bacteria. (5) Phosphorus tailings indirectly increased yield by modifying soil properties and pH, both positively linked to yield, while gcd-carrying bacteria had a modest positive influence. In summary, combining phosphorus tailings with a 20% reduction in chemical fertilizer reduces fertilizer use, recycles mining waste, and boosts corn production in acidic red soil, though further studies are needed to evaluate long-term environmental effects. Full article

Bacteriophages of the order Crassvirales are highly abundant and near-universal members of the human gut microbiome worldwide. Zeta crAss-like phages comprise a separate group in the order Crassvirales, and their genomes exhibit greater variability than genomes of crAss-like phages from other families within the order. Zeta crAss-like phages employ multiple adaptation mechanisms, ensuring their survival despite host defenses and environmental pressure. Some Zeta crAss-like phages use alternative genetic coding and exploit diversity-generating retroelements (DGRs). These features suggest complex evolutionary relationships with their bacterial hosts, sustaining parasitic coexistence. Mutations in tail fiber proteins introduced by DGR can contribute to their adaptation to changes in the host cell surface and even expand the range of their hosts. In addition, the exchange of DNA polymerases via recombination makes it possible to overcome the bacterial anti-phage protection directed at these enzymes. Zeta crAss-like phages continuously adapt due to genetic diversification, host interaction tweaks, and counter-defense innovations, driving an evolutionary arms race with hosts. Based on the genome characteristics of the Zeta crAss-like phages, we propose to separate them into the Echekviridae family (“эчәк”—“intestines” in Tatar) following the tradition of using the word “intestines” in different languages, suggested previously. Full article

During the breeding process of Macrobrachium rosenbergii, a male-to-female ratio of 1:3 or higher is typically adopted, so as a result, the quality of the male broodstock significantly influences the quality of the offspring. We observed that overused males exhibited notable changes in body color, particularly in the tail fan region, which turned orange or red due to the excessive accumulation of astaxanthin in the muscles and exoskeleton. Frequent mating also led to a significant decrease in male body weight, with histological analysis revealing disorganized muscle fiber patterns and increased tissue damage. To investigate the molecular mechanisms underlying these physiological changes, we performed transcriptomic and metabolomic analyses of muscle tissues. A total of 1069 differentially expressed genes (DEGs), 540 differentially expressed proteins (DEPs), and 385 differentially expressed metabolites (DEMs) were identified. Pathway analysis revealed that the DEGs were significantly enriched in pathways related to energy metabolism and degenerative diseases, while the DEMs were notably associated with cancer metabolism, signal transduction, substance transport, energy metabolism, nucleic acid metabolism, neurotransmission, immune response, and metabolic diseases. Proteome analysis showed that proteins and lipids were involved in muscle energy supply. These findings suggest that male M. rosenbergii upregulate energy metabolism in muscles to cope with frequent mating stress, but this adaptation leads to physiological damage. This study provides valuable insights for optimizing male broodstock selection and mating frequency in M. rosenbergii breeding practices. Full article

This study aimed to investigate the effect of varying levels of dietary protein on digestion, metabolism, serum biochemical indexes, and rumen microflora in Lanzhou fat-tailed sheep. A total of twenty 8-month-old healthy rams with an initial average body weight (BW 25.16 ± 1.09 kg) were selected and randomly divided into four dietary treatments with different protein levels P: 9.47%, MP: 10.53%, HP: 11.56%, and EHP: 12.61%. The rams underwent a 23 day adaptation period, and the experiment was conducted for 7 d. The results showed that with increased dietary protein levels, the apparent digestibility of dry matter (DM), crude protein (CP), acid detergent fiber (ADF), and urine energy significantly increased (p < 0.05), increasing by 8.65%, 7.31%, 6.22%, and 0.1%, respectively. In contrast, the digestibility of neutral detergent fiber (NDF) first increased and then plateaued with the increase in protein levels, and the digestibility of NDF in the HP group was the highest (p < 0.05). The Shannon, Simpson, Chao1, and Ace indices of rumen microorganisms in the four groups did not change significantly (p > 0.05). Additionally, at the phylum level, the relative abundance of Bacteroidota, Firmicutes, and Verrucomicrobiota collectively accounted for over 91% of the total phylum composition. At the genus level, there was an increase in the relative abundance of uncultured_rumen_bacterium and Rikenellaceae_RC9_gut_group in the LP group, whereas the relative abundance of Prevotella decreased. In comparison to the other three groups, the HP group exhibited an increase in the relative abundance of Firmicutes. In summary, dietary protein level had no significant effects on the rumen microflora structure and blood biochemical indexes. However, diets with a high protein level can improve the apparent digestibility of nutrients and energy use efficiency of Lanzhou fat-tailed sheep. Full article

Using Escherichia coli BW25113 as a host, we isolated a novel lytic phage from the commercial poly-specific therapeutic phage cocktail Sextaphage^® (Microgen, Russia). We provide genetic and phenotypic characterization of the phage and describe its host range on the ECOR collection of reference E. coli strains. The phage, hereafter named Sxt1, is a close relative of classical coliphage T3 and belongs to the Teetrevirus genus, yet its internal virion proteins, forming an ejectosome, differ from those of T3. In addition, the Sxt1 lateral tail fiber (LTF) protein clusters with those of the phages from the Berlinvirus genus. A comparison of T7, T3, and Sxt1 LTFs reveals the presence of insertions leading to the elongation of Sxt1 tail fibers, which, together with the difference in the HRDRs (host range-determining regions), might explain the expanded host specificity for the Sxt1. Full article

The rise of carbapenem-resistant Klebsiella pneumoniae (CRKP) presents a significant global challenge in clinical and healthcare settings, severely limiting treatment options. This study aimed to utilize a bacteriophage as an alternative therapy against carbapenem-resistant K. pneumoniae. A novel lytic N4-like Klebsiella phage, vB_kpnP_KPYAP-1 (KPYAP-1), was isolated from sewage. It demonstrated efficacy against the K62 serotype polysaccharide capsule of bla_OXA-48-producing K. pneumoniae. KPYAP-1 forms small, clear plaques, has a latent period of 20 min, and reaches a growth plateau at 35 min, with a burst size of 473 plaque-forming units (PFUs) per infected cell. Phylogenetic analysis places KPYAP-1 in the Schitoviridae family, Enquatrovirinae subfamily, and Kaypoctavirus genus. KPYAP-1 employs an N4-like direct terminal repeat mechanism for genome packaging and encodes a large virion-encapsulated RNA polymerase. It lacks integrase or repressor genes, antibiotic resistance genes, bacterial virulence factors, and toxins, ensuring its safety for therapeutic use. Comparative genome analysis revealed that the KPYAP-1 genome is most similar to the KP8 genome, yet differs in tail fiber protein, indicating variations in host recognition. In a zebrafish infection model, KPYAP-1 significantly improved the survival rate of infected fish by 92% at a multiplicity of infection (MOI) of 10, demonstrating its potential for in vivo treatment. These results highlight KPYAP-1 as a promising candidate for developing phage-based therapies targeting carbapenemase-producing K. pneumoniae. Full article

Antibiotics resistance is expanding amongst pathogenic bacteria. Phage therapy is a revived concept for targeting bacteria with multiple antibiotics resistances. In the present study, we isolated and characterized a novel phage from hospital treatment plant input, using Escherichia coli (E. coli) as host bacterium. Phage lytic activity was detected by using soft agar assay. Whole-genome sequencing of the phage was performed by using Next-Generation Sequencing (NGS). Host range was determined using other species of bacteria and representative genogroups of E. coli. Whole-genome sequencing of the phage revealed that Escherichia phage Ioannina is a novel phage within the Dhillonvirus genus, but significantly diverged from other Dhillonviruses. Its genome is a 45,270 bp linear double-stranded DNA molecule that encodes 61 coding sequences (CDSs). The coding sequence of CDS28, a putative tail fiber protein, presented higher similarity to representatives of other phage families, signifying a possible recombination event. Escherichia phage Ioannina lytic activity was broad amongst the E. coli genogroups of clinical and environmental origin with multiple resistances. This phage may present in the future an important therapeutic tool against bacterial strains with multiple antibiotic resistances. Full article

The molecular mechanism of how the infecting DNA of bacteriophage T4 passes from the capsid through the bacterial cell wall and enters the cytoplasm is essentially unknown. After adsorption, the short tail fibers of the infecting phage extend from the baseplate and trigger the contraction of the tail sheath, leading to a puncturing of the outer membrane by the tail tip needle composed of the proteins gp5.4, gp5 and gp27. To explore the events that occur in the periplasm and at the inner membrane, we constructed T4 phages that have a modified gp27 in their tail tip with a His-tag. Shortly after infection with these phages, cells were chemically cross-linked and solubilized. The cross-linked products were affinity-purified on a nickel column and the co-purified proteins were identified by mass spectrometry, and we found that predominantly the inner membrane proteins DamX, SdhA and PpiD were cross-linked. The same partner proteins were identified when purified gp27 was added to Escherichia coli spheroplasts, suggesting a direct protein–protein interaction. Full article

Introduction: Binge eating disorder (BED) is a psychiatric illness related to a high frequency of episodes of binge eating, loss of control, body image dissatisfaction, and suffering caused by overeating. It is estimated that 30% of patients with BED are affected by obesity. “Mindful eating” (ME) is a promising new eating technique that can improve self-control and good food choices, helping to increase awareness about the triggers of binge eating episodes and intuitive eating training. Objectives: To analyze the impact of ME on episodes of binge eating, body image dissatisfaction, quality of life, eating habits, and anthropometric data [weight, Body Mass Index (BMI), and waist circumference] in patients with obesity and BED. Method: This quantitative, prospective, longitudinal, and experimental study recruited 82 patients diagnosed with obesity and BED. The intervention was divided into eight individual weekly meetings, guided by ME sessions, nutritional educational dynamics, cooking workshops, food sensory analyses, and applications of questionnaires [Body Shape Questionnaire (BSQ); Binge Eating Scale (BES); Quality of Life Scale (WHOQOL-BREF)]. There was no dietary prescription for calories, carbohydrates, proteins, fats, and fiber. Patients were only encouraged to consume fewer ultra-processed foods and more natural and minimally processed foods. The meetings occurred from October to November 2023. Statistical analysis: To carry out inferential statistics, the Shapiro–Wilk test was used to verify the normality of variable distribution. All variables were identified as non-normal distribution and were compared between the first and the eighth week using a two-tailed Wilcoxon test. Non-Gaussian data were represented by median ± interquartile range (IQR). Additionally, α < 0.05 and p < 0.05 were adopted. Results: Significant reductions were found from the first to the eighth week for weight, BMI, waist circumference, episodes of binge eating, BSQ scale score, BES score, and total energy value (all p < 0.0001). In contrast, there was a significant increase in the WHOQOL-BREF score and daily water intake (p < 0.0001). Conclusions: ME improved anthropometric data, episodes of binge eating, body image dissatisfaction, eating habits, and quality of life in participants with obesity and BED in the short-term. However, an extension of the project will be necessary to analyze the impact of the intervention in the long-term. Full article

Intramuscular fat (IMF) is vital for meat tenderness and juiciness. This study aims to explore the IMF deposition mechanism and the related molecular markers in sheep. Two populations, Small-tail Han Sheep (STH) and STH × Suffolk (SFK) F₁ (SFK × STH), were used as the research object. Histological staining techniques compared the differences in the longissimus dorsi muscle among populations. A combination of transcriptome sequencing and biological information analysis screened and identified IMF-related target genes. Further, sequencing technology was employed to detect SNP loci of target genes to evaluate their potential as genetic markers. Histological staining revealed that the muscle fiber gap in the SFK × STH F₁ was larger and the IMF content was higher. Transcriptome analysis revealed that PIK3R1 and PPARA were candidate genes. Histological experiments revealed that the expressions of PIK3R1 mRNA and PPARA mRNA were lower in SFK × STH F₁ compared with the STH. Meanwhile, PIK3R1 and PPARA proteins were located in intramuscular adipocytes and co-located with the lipid metabolism marker molecule (FASN). SNP locus analysis revealed a mutation site in exon 7 of the PIK3R1 gene, which served as a potential genetic marker for IMF deposition. This study’s findings will provide a new direction for meat quality breeding in sheep. Full article

Enterobacteriaceae is a large family of Gram-negative bacteria composed of many pathogens, including Salmonella and Shigella. Here, we characterize six bacteriophages that infect Enterobacteriaceae, which were isolated from wastewater plants in the Wasatch front (Utah, United States). These phages are highly similar to the Kuttervirus vB_SenM_Vi01 (Vi01), which was isolated using wastewater from Kiel, Germany. The phages vary little in genome size and are between 157 kb and 164 kb, which is consistent with the sizes of other phages in the Vi01-like phage family. These six phages were characterized through genomic and proteomic comparison, mass spectrometry, and both laboratory and clinical host range studies. While their proteomes are largely unstudied, mass spectrometry analysis confirmed the production of five hypothetical proteins, several of which unveiled a potential operon that suggests a ferritin-mediated entry system on the Vi01-like phage family tail. However, no dependence on this pathway was observed for the single host tested herein. While unable to infect every genus of Enterobacteriaceae tested, these phages are extraordinarily broad ranged, with several demonstrating the ability to infect Salmonella enterica and Citrobacter freundii strains with generally high efficiency, as well as several clinical Salmonella enterica isolates, most likely due to their multiple tail fibers. Full article

The TP-84 bacteriophage, which infects Geobacillus stearothermophilus strain 10 (G. stearothermophilus), has a genome size of 47.7 kilobase pairs (kbps) and contains 81 predicted protein-coding ORFs. One of these, TP84_26 encodes a putative tail fiber protein possessing capsule depolymerase activity. In this study, we cloned the TP84_26 gene into a high-expression Escherichia coli (E. coli) system, modified its N-terminus with His-tag, expressed both the wild type gene and His-tagged variant, purified the recombinant depolymerase variants, and further evaluated their properties. We developed a direct enzymatic assay for the depolymerase activity toward G. stearothermophilus capsules. The recombinant TP84_26 protein variants effectively degraded the existing bacterial capsules and inhibited the formation of new ones. Our results provide insights into the novel TP84_26 depolymerase with specific activity against thermostable G. stearothermophilus and its role in the TP-84 life cycle. The identification and characterization of novel depolymerases, such as TP84_26, hold promise for innovative strategies to combat bacterial infections and improve various industrial processes. Full article