Antimicrobial Properties of Ethanolic and Methanolic Extracts of Finger millet (Eleusine coracana (L.) Gaertn.) Varieties Cultivated in Sri Lanka

The emerging significance of natural antimicrobial agents creates an imperative need to identify novel plant sources with antimicrobial activities. The objective of the present study was to evaluate antibacterial, antifungal and β-lactamase enzyme inhibitory activities of ethanolic and methanolic extracts of Ravi, Rawana and Oshadha finger millet varieties. Flours of whole grains of the finger millet varieties were extracted with absolute ethanol and methanol separately. Antibacterial activities against six antibiotic-sensitive and four antibiotic-resistant pathogenic bacterial strains were evaluated using the resazurin reduction assay. Antifungal activities against six antimicrobial-sensitive pathogenic fungal strains were evaluated using the agar tube dilution method. β-Lactamase enzyme inhibitory activity was evaluated using a standard method. Both ethanolic and methanolic extracts of the three finger millet varieties showed dose-dependent inhibitory activities against the tested antibiotic-sensitive and antibiotic-resistant bacterial strains while exhibiting high inhibitions against Gram-positive antibiotic-sensitive bacterial strains when compared to Gram-negative antibiotic-sensitive bacterial strains. The findings revealed the antibacterial potential of both ethanolic and methanolic extracts of the three finger millet varieties against antibiotic-sensitive Staphylococcus aureus (ATCC® 6538™) and Bacillus subtilis (ATCC® 23857™) strains and the minimum inhibitory concentrations of the extracts against S. aureus and B. subtilis were found to be 2.1 and 1.8 mg/ml, respectively. However, none of the extracts can be considered as significantly active against the tested antibiotic-sensitive and antibiotic-resistant bacterial strains when compared to the standard drugs. In addition, none of the extracts can be considered as active against the tested fungal strains at the tested concentrations. Nevertheless, all extracts showed more activities against the tested bacterial strains when compared to the tested fungal strains. Since all extracts showed less than 40% β-lactamase inhibitory activities even at 2 mg/ml concentration, they do not qualify as promising sources of β-lactamase inhibitors at the tested concentration.KEYWORDS: Antibacterial activity, Antifungal activity, Finger millet, β-Lactamase enzyme inhibitory activit

Psychometric properties of the Postgraduate Hospital Educational Environment Measure in an Iranian hospital setting

Background: Students’ perceptions of the educational environment are an important construct in assessing and enhancing the quality of medical training programs. Reliable and valid measurement, however, can be problematic – especially as instruments developed and tested in one culture are translated for use in another. Materials and method: This study sought to explore the psychometric properties of the Postgraduate Hospital Educational Environment Measure (PHEEM) for use in an Iranian hospital training setting. We translated the instrument into Persian and ensured its content validity by back translation and expert review prior to administering it to 127 residents of Urmia University of Medical Science. Results: Overall internal consistency of the translated measure was good (a=0.94). Principal components analysis revealed five factors accounting for 52.8% of the variance. Conclusion: The Persian version of the PHEEM appears to be a reliable and potentially valid instrument for use in Iranian medical schools and may find favor in evaluating the educational environments of residency programs nationwide

Iturin A Strongly Inhibits the Growth and T-2 Toxin Synthesis of Fusarium oxysporum: A Morphological, Cellular, and Transcriptomics Study

Fusarium oxysporum (F. oxysporum) is a common contaminant of dried fish, and the T-2 synthesis by this organism in dried fish products poses a serious public health risk. In this study, we investigated the effects of iturin A, a cyclic lipopeptide produced by Bacillus subtilis, on the growth and synthesis of the T-2 toxin of F. oxysporum, and transcriptomics was conducted. Results showed that the inhibitory effect of iturin A on F. oxysporum was significantly enhanced with an increase in iturin A concentrations. More specifically, compared with the control group, all indexes in the iturin A treatment group with 50 μg/mL were decreased to 24.84 mm, 0.33 × 106 cfu/mL, and 5.86 ng/mL for the colony diameter, number of spores, and concentration of T-2 toxin, respectively. Furthermore, iturin A was proven to destroy the integrity of cell membranes and cause a significant increase in ROS at 25 μg/mL or 50 μg/mL. Transcriptomic analysis revealed that with the treatment of iturin A, the genes of the oxidation-reduction process were up-regulated, while the gene expression of mycelial growth, cell integrity, transmembrane transport, energy metabolism, and others were down-regulated. More importantly, the Tri5 gene cluster was significantly inhibited. This study provided new insights into the mechanism for the inhibitory effect of iturin A on the growth and T-2 toxin synthesis of F. oxysporum and theoretical guidance for the application of iturin A in the preservation of dried aquatic products

Effect of immune stress on growth performance and immune functions of livestock: Mechanisms and prevention

Immune stress markedly affects the immune function and growth performance of livestock, including poultry, resulting in financial loss to farmers. It can lead to decreased feed intake, reduced growth, and intestinal disorders. Studies have shown that pathogen-induced immune stress is mostly related to TLR4-related inflammatory signal pathway activation, excessive inflammatory cytokine release, oxidative stress, hormonal disorders, cell apoptosis, and intestinal microbial disorders. This paper reviews the occurrence of immune stress in livestock, its impact on immune function and growth performance, and strategies for immune stress prevention

Population genomics of Megalobrama provides insights into evolutionary history and dietary adaptation

Megalobrama, a genus of cyprinid fish, is an economically important freshwater fish widely distributed in major waters of China. Here, we report the genome resequencing of 180 Megalobrama fish including M. amblycephala, M. skolkovii, M. hoffmanni, and M. pellegrini. Population structure indicated that geographically divergent Megalobrama populations were separated into six subgroups. A phylogenetic tree showed that M. skolkovii was more closely related to M. pellegrini than other species and M. hoffmanni was clustered apart from other Megalobrama species, showing a high nucleotide diversity in geographic groups. Treemix validated gene flow from M. amblycephala to M. skolkovii, suggesting that introgression may provide an important source of genetic variation in the M. skolkovii populations. According to the demographic history analysis, it is speculated that Megalobrama might have been originally distributed in the Pearl River with some spread to Hainan Island and northern China due to lower sea levels during the glacial period. Whole-genome selective sweeps analysis demonstrated that M. amblycephala likely developed an enhanced energy metabolism mostly through fatty acid degradation pathways whereas M. hoffmanni possibly regulate lipid absorption via the cholesterol metabolism pathway. Taken together, this study provides a valuable genomic resource for future genetic investigations aiming to improve genome-assisted breeding of Megalobrama species

Comparative analysis of flavor, taste, and volatile organic compounds in opossum shrimp paste during long‐term natural fermentation using E‐nose, E‐tongue, and HS‐SPME‐GC‐MS

The present study focused on the determination of color, flavor, taste, and volatile organic compounds (VOCs) changes of shrimp paste fermented for 1, 2, 3, and 8 years by E‐nose, E‐tongue, and headspace solid‐phase microextraction gas chromatography‐mass spectrometry (HS‐SPME‐ GC‐MS). During fermentation, the color of shrimp paste turned dark brown with decreases in L*, a*, and b* values. Inorganic sulfide odor was dominant in all fermented samples. The umami, richness, and aftertaste‐B reached a maximum in year 3 of fermentation. A total of 182 volatiles, including long‐chain alkanes, esters, aldehydes, olefins, ketones, acids, furans, and pyrazines, were detected. Sixteen VOCs including dimethyl disulfide, methional, trimethyl‐pyrazine, (E,E)‐2,4‐heptadienal, benzeneacetaldehyde were selected as flavor markers. Correlation analysis showed that 94 VOCs were related to saltiness while 40, 17, 21, 22, and 24 VOCs contributed to richness, umami, aftertase‐B, sourness, and bitterness, respectively. These novel data may help in optimizing fermentation duration to achieve target flavor indicators in opossum shrimp paste production

Preliminary report on intestinal flora disorder, faecal short-chain fatty acid level decline and intestinal mucosal tissue weakening caused by litchi extract to induce systemic inflammation in HFA mice

Certain foods are known as “heating” foods in Chinese medicine. Over-consumption of these foods can lead to symptoms known as “heating up”. These symptoms have been shown to be symptoms of systemic low-grade inflammation. However, the mechanism by which these foods cause inflammation is not clear. In this preliminary study, we investigated dysbacteriosis of the gut microbiota as a possible cause of inflammation by litchi, a typical “heating” food. A human flora-associated (HFA) mouse model (donor: n = 1) was constructed. After gavaging the mice with litchi extract suspension at low, medium and high doses (400, 800, 1600 mg/kg·d−1, respectively) (n = 3) for 7 days, the serum levels of inflammatory cytokines, gut microbiota, the concentration of SCFAs and the integrity of the intestinal mucosal barrier were measured. The results revealed significant increases in the abundance of Prevotella and Bacteroides. A significant increase in the abundance of Bilophila and a decrease in Megasomonas was observed in the high-dose group. High-dose litchi intervention led to a decrease of most SCFA levels in the intestine. It also caused a more than two-fold increase in the serum TNF-α level and LPS level but a decrease in the IL-1β and IL-6 levels. Medium- and high-dose litchi intervention caused widening of the intestinal epithelial cell junction complex and general weakening of the intestinal mucosal barrier as well as reduced energy conversion efficiency of the gut microbiota. These data suggest that litchi, when consumed excessively, can lead to a low degree of systematic inflammation and this is linked to its ability to cause dysbacteriosis of the gut microbiota, decrease SCFAs and weaken the intestinal mucosal tissues

Fungal diversity and mycotoxin contamination in dried fish products in Zhanjiang market, China

Dried fish are important dietary protein and income sources in Zhanjiang, China. Mycotoxins produced by pathogenic fungi that contaminate fish during processing can cause considerable hazard to consumer health. This study reports fungal diversity, total fungal counts and mycotoxin contamination of dried fish sold at the seafood market in Zhanjiang. Seven dried fish products (Hemibarbus maculatus, Pseudosciaena crocea, Lutjanus erythopterus, Thunnus thynnus, Scomberomorus niphonius, Eleutheronema tetradactylum, Trichiurus lepturus, n = 10) from seven retailers were analyzed for contaminated fungal species, occurrence frequency and residues analysis of four mycotoxins. Using potato dextrose agar (PDA) plate purification, morphology observation, internal transcribed spacer (ITS) sequence analysis, 25 fungal strains representing 12 genera from dried fish were systematically isolated and identified. Three dominant genera in dried fish were Fusarium sp. (80.4%), Penicillium sp. (70.7%) and Aspergillus sp.(63.9%). Other fungal genera were Neoscytalidium sp.(38.1%), Cutaneotrichosporon sp. (38.1%), Trichoderma sp.(20.3%), Naganishia sp.(15.3%), Kodamaea sp. (10.8%), Phialemoniopsis sp.(9.2%), Nigrospora sp.(7.3%), Ceriporia sp.(6.3%), Phellinus sp.(4.5%). Aspergillus flavus contamination was the higher and ranged from 1.10 × 10³ to 2.40 × 10⁴ cfu/g. The mean fungal contamination of other fungal species in dried fish ranged from 1.07 × 10² to 4.58 × 104 cfu/g. The total fungal counts of Fusarium sp. ranged from 1.09 × 10² to 2.11 × 10⁴ cfu/g, but the occurrence frequency is relatively high. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses showed that mycotoxin residues were present in 12 out of the 25 dried fish tested. Aflatoxin B1 (AFB₁) was the most frequently detected and the concentration ranged from 0.03 to 3.52 μg/kg. T-2 toxin (T-2), ochratoxin A (OTA), and deoxynivalenol (DON) concentrations ranged from 0.21 to 1.53, 0.03–2.21 and 0.71 μg/kg respectively. High occurrence of fungal populations and mycotoxins in dried fish sold in the Zhanjiang market pose a potential threat to consumer health. It is recommended that in future, advanced processing methods and controlled storage condition need to be used to minimize and if possible eliminate fungal contamination during dried fish processing

Growth and haemolytic activity of pathogenic Vibrio species in egg-fried-rice with different egg ratios

Growth and haemolytic activity of several pathogenic Vibrio species were compared in egg-fried-rice with different egg ratios. Egg-fried-rice preparations with rice-to-egg ratios of 4:1, 1:1, and 1:4 were inoculated with either Vibrio parahaemolyticus, V. cholerae, V. vulnificus, or V. alginolyticus and incubated for 24 h. Cell number, thermostable direct haemolysin (TDH) activity, and total haemolytic activity were determined. The cell number and total haemolytic activity increased in all Vibrio strains after 24 h, and these were most marked in egg-fried-rice with the highest egg content (1:4 (rice:egg) ratio; P<0.05). V. alginolyticus exhibited the maximal growth and V. parahaemolyticus the highest haemolytic activity, but only V. parahaemolyticus ATCC 33847, V. alginolyticus CAMT 21162, and V. alginolyticus HY 91101 showed TDH activity. Results suggest that lowering egg content in egg-fried-rice could reduce growth and virulence of Vibrio pathogens

Isolation and identification of lactic acid bacteria with probiotic potential from fermented flour of selected banana varieties grown in Sri Lanka

This study aimed at isolating and identifying lactic acid bacteria (LAB) with probiotic potential from fermented flour of selected banana varieties grown in Sri Lanka and evaluating their probiotic and safety attributes in vitro. Ten lactic acid bacteria were isolated from six varieties of fermented banana flour, kolikuttu, seeni parakum, ambul nadee, ambum, seeni and anamalu. The isolates were screened for phenotypical and biochemical characteristics. The selected isolates were identified by 16 S rRNA sequencing as Enterococcus durans (two strains), E. gallinarum, E. hirae, E. faecium (two strains), Lactobacillus plantarum, L. curieae, Weissella cibaria and Pediococcus acidilactici and their partial sequences were deposited in NCBI. Among them, six isolates were selected based on the results of in vitro safety attributes and evaluated for their probiotic attributes. Three isolates, namely, E. durans MF405179.1, E. faecium MF574466.1 and L. curieae MF405178.1 isolated from kolikuttu, seeni parakum and ambul nadee, respectively demonstrated tolerance to acid, gastric juice, bile, salt, phenol and temperature under gastric conditions, and also showed susceptibility to tested antibiotics. Among the selected isolates, E. durans MF405179.1 demonstrated the highest hydrophobicity and auto-aggregation of 69.91 % and 76.53 %, respectively. Further, it exhibited highest adhesion to both HCT116 and HT29 cell lines demonstrating 72.5 % and 74.16 % adhesion, respectively. This is the first report of isolation and characterisation of LAB strains with probiotic potential from flour of banana varieties kolikuttu, seeni parakum, ambul nadee, ambum, seeni and anamalu grown in Sri Lanka