Antimicrobial Traits Research Articles

Nutmeg vs mace: Evaluation of functional, nutritional, antioxidant and antimicrobial traits to employ as a food preservative

Nutmeg and mace from Myristica fragrans Houtt. are renowned for their culinary significance and medicinal properties. This study was designed to analyze the functional properties, proximate and mineral composition of nutmeg and mace, phytochemical estimation, antioxidant and antimicrobial potential of nutmeg and mace essential oils and oleoresins. The study was further elaborated by testing their synergistic interaction with streptomycin and antibiofilm potential of the most effective treatment. Results revealed better functional properties, higher fiber (35.2%) and mineral (K, Mg, P, Ca, Mn, Zn) content in nutmeg than mace. Nutmeg and mace essential oils were isolated by hydrodistillation and their respective oleoresins were prepared by the Soxhlet extraction method. Phytochemical screening showed a greater phenolic content in mace oleoresin (43.85 mg GAE/g of dw) and terpenoid content in mace essential oil (75.4%). Among all the treatments, mace oleoresin revealed best antioxidant potential against mustard oil degradation during its accelerated oxidation at 70 °C when stored for 7–28 days with minimum increase in peroxide, anisidine, thiobarbituric acid and total oxidation values of mustard oil. Mace oleoresin also revealed the maximum antibacterial activity against Staphylococcus aureus, Bacillus spp., Escherichia coli and Yersinia enterocolitica (MIC values; 180–530 μg/ml). It also revealed synergistic interaction with streptomycin against all the test bacteria along with a notable decrease in biofilm formation (50% of MIC.) GC-MS studies of mace oleoresin showed the presence of terpenoids, phenylpropanoids, phenols and fatty acids and their esters. Hence, mace oleoresins may be used as a natural and safe food preservative.

Development of transgenic Paulownia trees expressing antimicrobial thionin genes for enhanced resistance to fungal infections using chitosan nanoparticles

There is an increasing focus on genetically altering Paulownia trees to enhance their resistance against fungal infections, given their rapid growth and quality wood production. The aim of this research was to establish a technique for incorporating two antimicrobial thionin genes, namely thionin-60 (thio-60) and thionin-63 (thio-63), into Paulownia tomentosa and Paulownia hybrid 9501 through the utilization of chitosan nanoparticles. The outcomes revealed the successful gene transfer into Paulownia trees utilizing chitosan nanoparticles. The effectiveness of thionin proteins against plant pathogens Fusarium and Aspergillus was examined, with a specific focus on Fusarium equiseti due to limited available data. In non-transgenic Paulownia species, the leaf weight inhibition percentage varied from 25 to 36 %, whereas in transgenic species, it ranged from 22 to 7 %. In general, Paulownia species expressing thio-60 displayed increased resistance to F. equiseti, while those expressing thio-63 exhibited heightened resistance to A. niger infection. The thionin proteins displayed a strong affinity for the phospholipid bilayer of the fungal cell membrane, demonstrating their capability to disrupt its structure. The transgenic plants created through this technique showed increased resistance to fungal infections. Thionin-60 demonstrated superior antifungal properties in comparison to thio-63, being more effective at disturbing the fungal cell membrane. These findings indicate that thio-60 holds potential as a novel antifungal agent and presents a promising approach for enhancing the antimicrobial traits of genetically modified Paulownia trees.

Novel Probiotic Candidates in Artisanal Feta-Type Kefalonian Cheese: Unveiling a Still-Undisclosed Biodiversity.

Autochthonous dairy lactic acid bacteria (LAB) isolates encompass a natural source of starter, adjunct, or probiotic candidates. In this context, traditionally manufactured, using exclusively animal rennet, Feta-type cheeses were collected from five farms located in different regions of Kefalonia island (Greece). The primary objective of this study was to isolate and characterize novel LAB, thereby exploring the unmapped microbial communities of Kefalonian Feta-type cheese and identifying new potential probiotics. The initial screening, included a preliminary gastrointestinal (GI) tolerance assessment (acidic conditions and bile salts), followed by their safety evaluation (hemolytic activity and antibiotic susceptibility). Based on the preliminary screening, selected strains underwent molecular identification and were further investigated for their probiotic attributes (lysozyme and phenol resistance, antimicrobial traits, antidiabetic aspects, cholesterol reduction and adhesion, adhesion to Caco-2 cells, and milk acidification potential). The results showed that 49, out of the 93 retrieved isolates, exhibited resistance to GI conditions, whereas 18 met the safety criteria. The molecular identification revealed strains belonging to the species Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Lacticaseibacillus rhamnosus, and Lacticaseibacillus paracasei. The selected rod-shaped 14 isolates displayed a potential probiotic character. The best-performing isolates concerning cholesterol assimilation and adhesion, α-glucosidase inhibition, and epithelial adherence were Lpb. plantarum F89, F162, and F254 and Lcb. paracasei F214 and F216, whereas Lcb. paracasei F70 showed potential as a defined strain starter. The present study explores for the first time the biodiversity of traditionally fermented microbial communities in Kefalonian Feta-type cheese, revealing novel potential probiotic strains that can contribute to the development of innovative functional food products.

Soil Bacterial Diversity Responds to Long-Term Establishment of Perennial Legumes in Warm-Season Grassland at Two Soil Depths.

The introduction of rhizoma peanut (RP Arachis glabrata Benth) into bahiagrass (Paspalum notatum Flüggé) may require time to develop stable plant-soil microbe interactions as the microbial legacy of the previous plant community may be long-lasting. A previous study showed that <2 years of introducing rhizoma peanut into bahiagrass pastures minimally affected soil bacterial diversity and community composition. In this study, we compared the effects of the long-term inclusion of rhizoma peanut (>8 years) into bahiagrass on soil bacterial diversity and community composition against their monocultures at 0 to 15 and 15 to 30 cm soil depths using next-generation sequencing to target bacterial 16S V3-V4 regions. We observed that a well-established RP-bahiagrass mixed stand led to a 36% increase in bacterial alpha diversity compared to the bahiagrass monoculture. There was a shift from a soil bacterial community dominated by Proteobacteria (~26%) reported in other bahiagrass and rhizoma peanut studies to a soil bacterial community dominated by Firmicutes (39%) in our study. The relative abundance of the bacterial genus Crossiella, known for its antimicrobial traits, was enhanced in the presence of RP. Differences in soil bacterial diversity and community composition were substantial between 0 to 15 and 15 to 30 cm soil layers, with N2-fixing bacteria belonging to the phylum Proteobacteria concentrated in 0 to 15 cm. Introducing RP into bahiagrass pastures is a highly sustainable alternative to mineral N fertilizer inputs. Our results provide evidence that this system also promotes greater soil microbial diversity and is associated with unique taxa that require further study to better understand their contributions to healthy pastures.

Potencijal esencijalnog ulja ambrozije (Ambrosia artemisiifolia L.) u supresiji bakterijskog rasta

Plant essential oils have antimicrobial properties that are widely used in food preservation and aromatherapy and also have various medicinal uses. The way essential oil will affect the microorganisms widely depends on the type of microorganism and the type of oil used. Gram-positive bacteria are more sensitive to essential oil antimicrobial traits than gram-negative bacteria. Ragweed (Ambrosia artemisiifolia L.) essential oil has a wide range of antimicrobial applications; this oil is recommended for potential health benefits because of its antioxidant activity. The aim of this study was to examine the antibacterial potential of the ragweed essential oils against Escherichia coli, Bacillus subtilis and Salmonella spp. The antimicrobial effect of the oil was examined using a diffusion method test. Before the experiment, the inhibition zone of bacterial growth was determined using the antibiotic gentamicin. The results of the study confirmed the antimicrobial effect of ragweed oil on the growth of Salmonella spp. and Bacillus subtilis growth, while this oil had negligible effect on Escherichia coli growth. Moderate susceptibility of Salmonella spp. and Bacillus subtilis and resistance of E. coli was observed after ragweed treatment compared to the standard inhibition zone values proposed by EUCAST. This research confirms the potential application of ragweed essential oil in the inhibition of Salmonella spp. and Bacillus subtilis growth.

Antimicrobial Traits of Beauveria bassiana Against Rhizoctonia solani, the Causal Agent of Sheath Blight of Rice Under Field Conditions.

Beauveria bassiana, an entomopathogenic fungus, has recently drawn attention worldwide not only as a potential biocontrol agent against insect pests but also for its other beneficial roles as plant disease antagonist, endophyte, plant growth promoter, and beneficial rhizosphere colonizer. In the present study, 53 native isolates of B. bassiana were screened for antifungal ability against Rhizoctonia solani, the causal agent of sheath blight of rice. Also, the mechanisms underlying such interaction and the responsible antimicrobial traits involved were studied. Following this, potential B. bassiana isolates were assayed against the reduction of sheath blight of rice under field conditions. The results showed that B. bassiana exhibited antagonistic behavior against R. solani with a percent mycelial inhibition recorded maximum of up to 71.15%. Mechanisms behind antagonism were the production of cell-wall-degrading enzymes, mycoparasitism, and the release of secondary metabolites. The study also deciphered several antimicrobial traits and the presence of virulent genes in B. bassiana as a determinant of potential plant disease antagonists. Under field conditions, combined application of the B. bassiana microbial consortium as a seed treatment, seedling root dip, and foliar sprays showed reduced sheath blight disease incidence and severity up to 69.26 and 60.50%, respectively, along with enhanced plant-growth-promoting attributes. This is one of the few studies investigating the antagonistic abilities of the entomopathogenic fungus B. bassiana against phytopathogen R. solani and the underlying mechanisms involved.

Characterization of phyto-components with antimicrobial traits in supercritical carbon dioxide and soxhlet Prosopis juliflora leaves extract using GC-MS

This study aimed to screen the bioactive compounds from Prosopis juliflora leaf supercritical fluid extract and to assess its antimicrobial properties. Supercritical carbon dioxide and Soxhlet methods were used for extraction. The extract was subjected to Gas Chromatography-Mass Spectrometer (GC-MS) and Fourier Transform Infrared for the characterization of the phyto-components. When compared to soxhlet extraction, more components (35) were eluted by supercritical fluid extraction (SFE), according to GC-MS screening. Rhizoctonia bataticola, Alternaria alternata, and Colletotrichum gloeosporioides were all successfully inhibited by P. juliflora leaf SFE extract, which demonstrated strong antifungal properties with mycelium percent inhibition of 94.07%, 93.15%, and 92.43%, respectively, compared to extract from Soxhlet, which registered 55.31%, 75.63% and 45.13% mycelium inhibition respectively. Also, SFE P. juliflora extracts registered higher zone of inhibition 13.90 mm, 14.47 mm and 14.53 mm against all three test food-borne bacterial pathogens viz Escherichia coli, Salmonella enterica and Staphylococcus aureus respectively. Results obtained from GC-MS screening revealed that SFE is more efficient than soxhlet extraction in recovering the phyto-components. P. juliflora may provide antimicrobial agents, a novel natural inhibitory metabolite.

Screening the efficacy of extracts of different spices in inhibiting the growth of foodborne bacterial isolates

Owing to the presence of a diverse group of phytochemicals, spices could be potential sources of antibacterial and antioxidant agents. The present investigation was aimed to determine and compare the antimicrobial activities of different spices. A total of 5 spices including cardamom (Seeds, Elettaria cardamomum), cinnamon (Barks, Cinnamomum verum), clove (Flower buds, Syzygium aromaticum), Indian bay leaf or Tejpat (Dried leaves, Cinnamomum tamala), and cumin (Seeds, Cuminum cyminum) were collected. Different extracts (crude, aqueous, ethanolic, and methanolic) of spices were prepared and examined for antimicrobial activity against previously isolated foodborne bacterial isolates. Extracts from the tested spices showed significant inhibitory effects (mostly with &gt;10 mm mean zone of inhibition) as revealed by the agar well diffusion technique. Clove among the tested spices was found to be the prominent one in eliminating foodborne pathogens. Methanolic extracts followed by ethanolic extracts were determined to be most effective against the bacterial isolates when the relative effectivity of different extracts was compared. The frequently encountered minimal inhibitory and bactericidal concentrations of the spices were 12 and 24 mg/mL, respectively. All the spice extracts showed considerable antimicrobial traits which validate their potential and applicability as natural food preservatives and decontaminants.

Exploring the influence of tin in micro-structural, magneto-optical and antimicrobial traits of nickel oxide nanoparticles

Transition metal oxide nanoparticles, especially nickel oxide (NiO) have profound interests to the scientific commune on account of their dimension-reliant attributes and peculiar progression in optical, electrochemical, and magnetic characteristics. Herein, the undoped and tin (Sn) doped nickel oxide nanoparticles of varied concentrations were synthesized by highly favourable citrate assisted sol-gel technique. An array of extensive investigations were discussed on the structural, optical, and magnetic properties of synthesized nanoparticles. The crystallite size and strain of as-synthesized samples decreased with significant augmentation in dopant discrepancy which was confirmed by Scherrer and Williamson-Hall model. The optical energy band gap was evaluated from UltraViolet-visible (UV-vis) spectroscopy analysis and a notable blue shift was observed over the wide absorption spectrum. Refractive index, Urbach energy, and other optical parameters anchored in opto-electrical applications were evaluated from optical studies. Fourier Transform Infrared Spectroscopy (FTIR) analysis conducted at room temperature from spectral span 400–4000 cm−1 affirmed the cubic configuration and elucidated bond lengths of pure and tin-doped nanoparticles. Scanning electron microscopy studies portrayed surface morphological features and slight porous particles were observed. Transmission Electron Microscopy (TEM) analysis confirmed the spherical shape of nanoparticles and the grain size estimated is in accordance with the XRD results. The surface area and porosity of pure and doped samples were deeply investigated by Brunauer-Emmett-Teller (BET) analysis. Magnetic parameters such as saturation magnetization, coercivity, retentivity, magnetic moment were enumerated from Vibrating Sample Magnetometer (VSM) investigations and two critical magnetic parameters were extracted from the Law of Approach to Saturation model (LAS). The sample with 6% of Sn shows the highest coercivity of 147 Oe. Further, synthesized pure and doped traces of nickel oxide nanoparticles were deliberated for their competent application in the domain of antibiotics independent antimicrobial activity.

The Role of Selenium Nanoparticles in Agriculture and Food Technology.

Selenium (Se) is an essential micronutrient for diverse organisms such as mammals, bacteria, some insects and nematodes, archaea, and algae, as it is involved in a large number of physiological and metabolic processes and is part of approximately 25 selenoproteins in mammals. In plants, Se has no essential metabolic role, high concentrations of inorganic Se can lead to the formation of Se-amino acids, and its incorporation into selenoproteins can generate toxicity. Conversely, low doses of Se can trigger a variety of beneficial effects as an antioxidant, antimicrobial, or stress-modulating agent without being an essential element. Therefore, Se can generate toxicity depending on the dose and the chemical form in which it is supplied. Selenium nanoparticles (SeNPs) have emerged as an approach to reduce this negative effect and improve its biological properties. In turn, SeNPs have a wide range of potential advantages, making them an alternative for areas such as agriculture and food technology. This review focuses on the use of SeNPs and their different applications as antimicrobial agents, growth promoters, crop biofortification, and nutraceuticals in agriculture. In addition, the utilization of SeNPs in the generation of packaging with antioxidant and antimicrobial traits and Se enrichment of animal source foods for human consumption as part of food technology is addressed. Additionally, possible action mechanisms and potential adverse effects are discussed. The concentration, size, and synthesis method of SeNPs are determining factors of their biological properties.

Fluorescent pseudomonads (FPs) as a potential biocontrol and plant growth promoting agent associated with tomato rhizosphere

A total of 87 FPs have been isolated from tomato (Lycopersicon esculentum) rhizosphere and evaluated by dual plate assay method for the antimicrobial activity of Ralstonia solanacearum. Of which, 30 FPs showed antagonistic activity against R. solanacearum with the zone of inhibitions (ZOI) ranging from 19 mm to 28 mm. Similarly, antagonistic FPs significantly controlled various fungal phytopathogens such as Rhizoctonia solani (6.3 mm−20 mm), Macrophomina phaseolina (8.7 mm−19.3 mm), Fusarium oxysporum (7.3 mm−30.7 mm), and Sclerotium rolfsii (5.3 mm−21 mm). The cell-free culture filtrate of Pseudomonas sp VSMKU3054 significantly suppressed the fungal pathogens and increased the root and shoot length of the tomato seedlings compared to the control. Furthermore, the antagonistic FPs effectively produced lytic enzymes and antimicrobial traits such as amylase (6), protease (30), cellulase (28), pectinase (12), chitinase (22), gelatinase (27), siderophore (28), hydrogen cyanide (25), phosphate solubilization (30), and Indole acetic acid (IAA) (23). Genetic diversity of FPs was assessed by BOX-PCR with specific primers revealed that two distinct clusters were observed, whereas, RFLP analyses were showed that 5 to 16 bands ranged from 75 bp to 1.2 bp with two major clusters using restriction enzyme HaeIII. The antibiotic encoding genes were detected from FPs, of which 10 FPs were positive for 2,4-diacetylphloroglucinol (DAPG), 9 FPs were positive for pyoleuterin (PLT), 10 FPs were positive for hydrogen cyanide (HCN) and none of them obtained pyrrolnitrin (PRN) with respective primers. Based on the superior antagonistic isolates against R. solanacearum and phytofungal pathogens and other antimicrobial traits, the isolate VSMKU3054 was selected for further studies. Based on the morphological, physiological and 98% of 16 s rDNA sequence similarity, the selected isolate VSMKU3054 was identified as Pseudomonas fluorescens. Further, the potential isolate P. fluorescens VSMKU3054 and cell free culture filtrate remarkably enhance tomato seedling growth such as root and shoot length, fresh and dry weight and vigor index compared to control. This study indicated that rhizospheric isolates of FPs have more potential for plant growth promotion and plant protection from plant pathogenic microbes.

Eugenol-Containing Essential Oils Loaded onto Chitosan/Polyvinyl Alcohol Blended Films and Their Ability to Eradicate Staphylococcus aureus or Pseudomonas aeruginosa from Infected Microenvironments.

Chronic wounds (CW) create numerous entryways for pathogen invasion and prosperity, further damaging host tissue and hindering its remodeling and repair. Essential oils (EOs) exert quick and efficient antimicrobial (AM) action, unlikely to induce bacterial resistance. Cinnamon leaf and clove oils (CLO and CO) display strong AM activity, namely against Staphylococcus aureus and Pseudomonas aeruginosa. Chitosan (CS) is a natural and biodegradable cationic polysaccharide, also widely known for its AM features. CS and poly (vinyl alcohol) (PVA) films were prepared (ratio 30/70 w/w; 9 wt%) by the solvent casting and phase inversion method. The film’s thermal stability and chemical composition data reinforced polymer blending and EO entrapment. Films were supplemented with 1 and 10 wt% of EO in relation to total polymeric mass. The film thickness and degree of swelling (DS) tended to increase with EO content, particularly with 10 wt % CLO (* p < 0.05). UV-visible absorbance scans in the 250–320 cm−1 region confirmed the successful uptake of CLO and CO into CS/PVA films, particularly with films loaded with 10 wt% EO that contained 5.30/5.32 times more CLO/CO than films supplemented with 1 wt% EO. AM testing revealed that CS films alone were effective against both bacteria and capable of eradicating all P. aeruginosa within the hour (*** p < 0.001). Still, loaded CS/PVA films showed significantly improved AM traits in relation to unloaded films within 2 h of contact. This study is a first proof of concept that CLO and CO can be dispersed into CS/PVA films and show bactericidal effects, particularly against S. aureus, this way paving the way for efficient CW therapeutics.

Antimicrobial traits of different medicinal plants locally available in Bangladesh

Background: Medicinal plants have been commonly used in traditional medicine against different ailment from ancient time. The present study was an attempt to determine the anti-bacterial traits of commonly available medicinal plants, especially having topical uses. Methods: A total of four types of locally available medicinal plant samples inclusive of Turmeric (Curcuma longa, rhizome), Marigold (Tagetes minuta, leaves), Durva Grass (Cynodon dactylon, whole plant), and Hibiscus (Hibiscus rosa-sinensis, leaves) were collected. Crude, hot water, and solvent (ethanolic and methanolic extracts of the samples) were tested for their antimicrobial traits by agar well-diffusion method on Mueller-Hinton agar. The minimal inhibitory concentration (MIC) of each sample was determined by the microdilution technique. Microbiological quality of the samples was also checked. Results: Microbial contaminations were found in all the samples. Beside viable bacteria and fungi, all samples contained Staphylococcus spp. and Pseudomonas spp. The proliferation of Klebsiella spp. was observed in the majority of the samples. Notable antimicrobial activities were exhibited by the medicinal plant parts tested in this study. Ethanolic and methanolic extracts showed remarkable efficiency in eliminating the growth of tested bacterial isolates although crude and hot water extracts projected no considerable inhibitory effects. The majority of the samples had a MIC value at 12 mg/mL. Conclusion: The findings of the present study reveal that the medicinal plant samples had remarkable antimicrobial traits which portray their potential for the commercial application against different infectious diseases.

Occurrences of Antimicrobial Resistance in &amp;lt;i&amp;gt;Escherichia coli&amp;lt;/i&amp;gt; Isolated from Intestinal Faecal Contents of &amp;lt;i&amp;gt;Covurs splendens&amp;lt;/i&amp;gt; (Indian Crow)

<i>Introduction</i>: Indian crows have been commented to present significant physical community harm with respect to property damage and agricultural products. However the public health significant of these birds in the developing countries has been underrated. Their scavenging nature might result into spread of pathogens in the public as well as the antimicrobial traits among bacteria. In order to gain the insight into the role of Indian crows as carriers and reservoir of multi-resistant E. coli; broad spectrum antimicrobial agents were tested using a wild E. coli isolated from the birds themselves. <i>Methods</i>: The <i>Escherichia coli</i> bacteria were isolated and identified from intestinal contents of 30 Indian crows in Morogoro. An 100μl Intestinal contents were spread on MacConkey for <i>E. coli</i> isolation. A total of eight (8) antimicrobial agents: STX (25 μg), AMP (10 μg), AMC (30 μg), CN (10 μg), CIP (5 μg), TE (30 μg), S (10 μg) and CTX (30 μg) were used. <i>E. coli</i> ATCC 25922 and included as control strains. <i>Results</i>: The resistance TE and SXT were the most prevalent (90%), followed by AMP (76.7%) and S (73.3%), CIP (53.3%), and CTX (36.7%). The susceptibility of these isolates was high in CN 96.7%. It also shown among 30 of the <i>E. coli</i> isolates; twenty-eight of them presented multiple antibiotic resistances. <i>Conclusion</i>: The results have shown that Indian crow can serve as a reservoir of antibiotic-resistant <i>E. coli</i>, and potentially transmit such <i>E. coli</i> over long distances. This is a hidden public health threat as these crows move from one place to another and is found in residential areas contaminating water and food with resistant bacteria and antimicrobial resistance strains.

Assessment of Safety and Probiotic Traits of Enterococcus durans OSY-EGY, Isolated From Egyptian Artisanal Cheese, Using Comparative Genomics and Phenotypic Analyses.

An Enterococcus durans strain, designated OSY-EGY, was previously isolated from artisanal cheese. In this work, comparative genomic and phenotypic analyses were utilized to assess the safety characteristics and probiotic traits of the bacterium. The comparative genomic analysis revealed that the strain is distantly related to potentially pathogenic Enterococcus spp. The genome was devoid of genes encoding acquired antibiotic resistance or marker virulence factors associated with Enterococcus spp. Phenotypically, the bacterium is susceptible to vancomycin, ampicillin, tetracycline, chloramphenicol, and aminoglycosides and does not have any hemolytic or gelatinase activity, or cytotoxic effect on Caco-2 cells. Altogether, these findings confirm the lack of hazardous traits in E. durans OSY-EGY. Mining E. durans OSY-EGY genome, for probiotic-related sequences, revealed genes associated with acid and bile salts tolerance, adhesion, competitiveness, antioxidant activitiy, antimicrobial activity, essential amino acids production, and vitamins biosynthesis. Phenotypically, E. durans OSY-EGY was tolerant to acidic pH (3.0), and presence of 0.3% bile salts. The bacterium showed adhesion capability to Caco-2 cells, cholesterol-lowering effect, DPPH scavenging activity, and antimicrobial activity against several Gram-positive pathogenic bacteria. Based on the current work, we propose that E. durans OSY-EGY is a potentially safe strain with desirable probiotic and antimicrobial traits. Thus, the investigated strain could be a promising candidate for several industrial applications.

Genome sequence of Vibrio sp. OULL4 isolated from shellfish

The members of Vibrionaceae family are Gram-negative bacterium are ubiquitous in marine and estuarine environments. This diverse group of bacteria include many pathogenic strains that potentially cause infection to humanand aquaculture animals. Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus are among the few recognized as a major, worldwide cause gastroenteritis, particularly in countries where seafood consumption is high. The control of these vibrios has been a hurdle due to the rising numbers of antibiotic resistant strains in the environments. We report the genome sequence of Vibrio sp. OULL4 isolated from shellfish. The availability of this genome sequence will facilitate the study of its antimicrobial traits, as well as add our knowledge of Vibrio sp. diversity and evolution.

Insect venom peptides as potent inhibitors of Escherichia coli ATP synthase

Insect venom peptides (IVPs) eumenitin, lasiocepsin, lycosin1, mastoparanB, panurgine1, and protonectin possess antibacterial properties, and the ubiquitous enzyme ATP synthase has a peptide-binding site. In the present study, we studied the effect of IVPs on binding and inhibition of three Escherichia coli strains (wild type, mutant, and null) and isolated E. coli ATP synthase. IVPs and their C-terminal amide (–NH2) analogs caused variable inhibition of membrane-bound F1Fo ATP synthase. While wild type E. coli growth was substantially hampered, null E. coli growth was near normal in the presence of IVPs and their C-terminal–NH2 analogs. The presence of C-terminal–NH2 groups on IVPs resulted in increased inhibition of ATP synthase and reduced growth of E. coli strains. Insignificant inhibition of the βDELSEED-motif mutant enzyme with the βAAAAAAA-motif confirmed that IVPs interact with the βDELSEED-motif, also known as the peptide-binding site. The higher level of growth loss in E. coli strains by eumenitin, lasiocepsin, lycosin1, mastoparanB, panurgine1, and protonectin and their C-terminal–NH2 analogs suggested the likelihood of additional cellular or molecular targets. IVPs caused inhibition of E. coli strains, which demonstrates an association between antimicrobial traits of IVPs and bacterial ATP synthase.

Genome sequence of Vibrio sp. SALL 6 isolated from shellfish

Members of the Vibrionaceae family are well known as foodborne pathogen that cause hazard to human in many forms of clinical infection and also affecting aquaculture via infection to livestock. This pathogen has caused seafood associated gastroenteritis cases in many countries including United States, Asian, and South East Asian countries. Antibiotics are usually used as prophylactic and therapeutic to manage the rising Vibrio infections, however, this in turn led to emergence of antibiotic resistant strains in the environments. Vibrio sp. SALL 6 isolated from shellfish was selected for genome sequencing to further explore its antimicrobial traits. Here, a high-quality genome sequence of Vibrio sp. SALL 6 is reported, while its genome reveals a potential for future antibiotic resistance managements.

Microbiological quality and antimicrobial potential of extracts of different spices

The present study was carried out to determine the antimicrobial traits of spices for validating its potential as food preservatives and therapeutic alternatives along with their microbiological quality. In this regard, a total of 4 locally available spices including Saffron (Crocus sativus), Nutmeg (Myristica fragrans), Mace (Myristica fragrans) and Shahi Jeera (Bunium bulbocastanum) were collected from different areas of Dhaka, Bangladesh. The samples were found to harbor total viable bacteria and fungi up to 105 CFU/g and 104 CFU/g, respectively. Presence of specific bacterial species was also documented. Among them, Staphylococcus spp. and Pseudomonas spp. were prevalent as found in all samples. Presence of Bacillus spp. and Escherichia coli were also evident in Nutmeg and Shahi Jeera. Whereas, Klebsiella spp. was absent in all samples. Antibacterial properties of the samples were determined by the agar well diffusion method. The ethanolic and methanolic extracts of all the spice samples showed remarkable antibacterial activity against most of the tested bacterial isolates, although crude extract could merely affect the bacterial growth. The presence of antibacterial effects revealed that the spices could be used in food conservation and as natural antimicrobials.

In Silico Identification of Antimicrobial Peptides in the Proteomes of Goat and Sheep Milk and Feta Cheese.

Milk and dairy products are a major functional food group of growing scientific and commercial interest due to their nutritional value and bioactive “load”. A major fraction of the latter is attributed to milk’s rich protein content and its biofunctional peptides that occur naturally during digestion. On the basis of the identified proteome datasets of milk whey from sheep and goat breeds in Greece and feta cheese obtained during previous work, we applied an in silico workflow to predict and characterise the antimicrobial peptide content of these proteomes. We utilised existing tools for predicting peptide sequences with antimicrobial traits complemented by in silico protein cleavage modelling to identify frequently occurring antimicrobial peptides (AMPs) in the gastrointestinal (GI) tract in humans. The peptides of interest were finally assessed for their stability with respect to their susceptibility to cleavage by endogenous proteases expressed along the intestinal part of the GI tract and ranked with respect to both their antimicrobial and stability scores.