AMB Express最新文献

Amp0279 (EC 3.4.11.24, GenBank: CP000817.1) is a Co²⁺-dependent leucine aminopeptidase from the Lysinibacillus sphaericus C3-41 genome. After analyses using molecular docking and spatial structure analysis, site-directed mutagenesis mutants were performed as Amp0279-R131E, Amp0279-R131H, Amp0279-R131A and Amp0279-E349D. The optimum pH of Amp0279-R131E was shifted from the original 8.5 to 7.5, and the overall electrostatic potential was shifted towards acidic. Compared with the original enzyme, the mutant proteins all gained better structural stability, especially the apparent melting temperature (T_m) of Amp0279-R131H increased from 41.8 to 45.5 °C. Morever, when protein was bound to the substrate, the T_m of Amp0279-R131E was increased by 7.3 °C and Amp0279-R131H increased by 5.4 °C, compared to the original enzyme. This is consistent with the results that the mutants acquired higher binding energies to the substrates, and an increase the hydrogen bonding force. In addition, the molecular docking of mutant and substrate revealed that the truncation of R131 contributes to the increase in the binding capacity of the substrate molecules to the active centre. In contrast, the presence of π-Cation interactions generated by R131 with the substrate has an important effect on the ability of Amp0279 to hydrolyse the substrate. This study demostrated that R131 is a key site for activity and stability, which is important in the future exploration of the functional structure of Amp0279.

Anaerobic bacteria, such as Lactobacillus plantarum (LP), are known to play a significant role in maintaining gut health and protecting against enteric pathogens in animals. The present study aimed to develop a safe, affordable, and eco-friendly method for producing LP-based probiotics and evaluate their efficacy in mitigating Salmonella-induced diarrhea in broiler chickens. The study employed three different culture media (MRS, TSB, and Baird Parker) to grow LP, which was then dried using a spray-drying technique to produce a stable probiotic formulation. When administered to broiler chickens, the LP probiotic derived from the MRS medium significantly improved body weight gain (4.147-fold increase over 4 weeks) compared to the other two culture conditions. Importantly, the LP probiotic treatment could substantially reduce the diarrhea index in broilers, with up to an 86.45% improvement in Salmonella-induced enteric infections. The beneficial effects were attributed to the ability of LP to modulate the gut microbiome, enhance the integrity of the intestinal mucosa, and mitigate the pathogenic effects of Salmonella. These findings demonstrate the potential of anaerobic Lactobacillus plantarum as a safe and effective probiotic intervention for controlling enteric diseases and improving production outcomes in poultry farming. The developed method provides a sustainable approach to harness the beneficial properties of this anaerobic bacterium for animal health and welfare.

Spent mushroom substrate (SMS) is a by-product remaining after harvesting mushrooms. We evaluated the effect of substituting chicken feed with 0-100% of Pleurotus eryngii and Lentinula edodes SMS at different stocking densities (200-1000 larvae/box) on development, composition, and substrate reduction of black soldier fly (Hermetia illucens) larvae. Although the survival rate was not significantly different, feeding pure SMS led to a low growth rate. The substitution level of SMS negatively correlated with individual larval weight, total harvested biomass, larval growth rate (LGR), feed conversion ratio (FCR), substrate reduction, and waste reduction index (WRI) except for the 20% substitution. Feeding 40% SMS resulted in the highest number of prepupae. In the density experiment, the heaviest larvae (220-239 mg fresh weight) were obtained at 200 larvae/box in the 0% SMS group. The frass residue and FCR decreased with increased density. Remarkably, when feeding 20% SMS at 250 larvae/box, the harvested biomass, LGR, and FCR did not differ significantly from the 0% SMS control, whereas some of the higher densities led to a deterioration. In fact, the frass residue, substrate reduction, and WRI were even improved at 250 larvae/box in the 20% SMS group. The chemical analyses of larvae reared on 20% SMS at 250 larvae/box showed comparable ash and fat contents and a higher protein content compared to the 0% SMS group. Accordingly, up to 20% of a standard diet such as chicken feed can be replaced by low-cost SMS without disadvantages for breeding.

Increasing evidence exists that the gut microbiome influences toxicity as well as outcomes in a variety of cancers. To investigate the role of the gut microbiome in pediatric neuro-oncology, microbiome analysis has been included in multiple prospective pediatric neuro-oncology clinical trials (NCT05009992, NCT04732065, NCT04775485). In these trials, the OMNIgene-GUT^tm preservation tubes are used for the collection of the feces. OMNIgene-GUT^tm has demonstrated reliability in preserving the composition of the gut microbiome in adults; however, its validation for use in the pediatric population remains limited. Therefore, we compared the quality of the DNA by 16S rRNA gene sequencing after various methods of stabilizing fecal samples in pediatric populations, from the direct freeze method at - 80 °C to preserving samples with OMNIgene-GUT^tm at room temperature for various durations. Our results showed that there were no statistically significant differences between the alpha-diversity, and beta-diversity. However, pairwise differential abundance analyses demonstrated that OMNIgene-GUT™ is superior in maintaining microbial community structure compared to storing samples without any preservation method. With the OMNIgene-GUT^tm's stabilization of the fecal samples being superior and its ease-of-use benefits, it proves to be a valid and ideal method of stabilizing fecal samples for current and future pediatric clinical trials.

Ethylene glycol (EG) is a versatile molecule produced in the petrochemical industry and is widely used to manufacture plastic polymers, anti-freeze, and automotive fluids. Biotechnological production of EG from xylose, a pentose present in lignocellulose biomass hydrolysates, has been achieved by the engineering of bacteria, such as Escherichia coli and Enterobacter cloacae, and the yeast Saccharomyces cerevisiae with synthetic pathways. In the present work, the Dahms pathway was employed to construct Komagataella phaffii strains capable of producing EG from xylose. Different combinations of the four enzymes that compose the synthetic pathway, namely, xylose dehydrogenase, xylonate dehydratase, dehydro-deoxy-xylonate aldolase, and glycolaldehyde reductase, were successfully expressed in K. phaffii. Increased production of EG (1.31 g/L) was achieved by employing a newly identified xylonate dehydratase (xylD-HL). This xylonate dehydratase allowed 30% higher EG production than a previously known xylonate dehydratase (xylD-CC). Further strain engineering demonstrated that K. phaffii possesses native glycolaldehyde reduction and oxidation activities, which lead to pathway deviation from EG to glycolic acid (GA) production. Finally, cultivation conditions that favor the production of EG over GA were determined.

To feed the world's growing population, the agriculture sector has recently had to strike a balance between reducing its detrimental effects on ecosystems and human health and boosting resource efficiency and production. In reality, pesticides and fertilizers are vital to agriculture and are useful instruments that farmers can employ to increase yield and guarantee steady productivity throughout the seasons under both favorable and unfavorable conditions. Therefore, in the present study, fertilizing with potassium citrate as a foliar spray and humic acid (HA) as a soil application allowed for the evaluation of vegetative growth parameters (plant height, number of leaves/plant), total phenolic content, total carbohydrate, antioxidant activity, the essential oil (EO) composition, and bulb yield of garlic (Allium sativum L.). These were carried out in two field experiments throughout the 2020-2021 and 2021-2022 growth seasons. A gas chromatography-mass spectroscopy (GC-MS) apparatus was performed to determine the chemical composition of the isolated EOs. The antifungal activity of the EOs was assessed against two fungi, Fusarium proliferatum and Macrophomina phaseolina, that cause geranium plants to wilt and decay. The findings indicated that applying HA at a rate of 2 g/L with potassium citrate at a rate of 5 or 10 mL/L produced garlic bulbs with the highest levels of productivity and diameter. The diverse treatments between HA with potassium citrate resulted in significant variations in the bioactive components, such as total phenol content, antioxidant activity, total carbohydrate, and sulfur content. The analysis of the EOs revealed the presence of dimethyl trisulfide, diallyl disulfide, methyl 2-propenyl trisulfide, allitridin, and methyl allyl disulfide and allyl tetrasulfide as main compounds. By gradually increasing the concentration of the garlic EO to 4000 µg/mL compared to the control, the inhibition percentage of fungal growth of F. proliferatum and M. phaseolina was increased. In conclusion, a high concentration of HA with potassium citrate (5 or 10 mL/L), may be suitable and highly appreciated as a fertilizer application to enhance the productivity and EOs content of garlic plants.

A high cellulase-producing bacterial isolate TS4 was recovered from an Egyptian soil sample and identified using 16S rRNA gene sequencing as Streptomyces thermodiastaticus. One-factor-at-a-time (OFAT) preliminary studies were carried out to determine the key factors affecting cellulase production by S. thermodiastaticus and their optimum ranges. The initial pH of the medium, carboxymethyl cellulose (CMC), tryptone, and NaCl concentrations were further optimized using a response surface Central Composite design. Fermentation under optimized variables of initial pH 6.0, presence of CMC, tryptone, and NaCl at concentrations of 2%, 0.03%, and 0.12%, respectively, resulted in 3.24 fold increase in cellulase productivity (2023 U/L) as compared to that under basal conditions (625 U/L). Cellulase production was also improved with a 4 Kilogray (KGy) dosage of gamma radiation. In comparison to the wild-type strain under basal circumstances, S. thermodiastaticus produced 5.1 fold more cellulase after a combination of model-based optimization and gamma radiation mutation. Cellulase was partially purified using ammonium sulfate precipitation followed by dialysis. The resulting cellulase was 1.74 times purified and its specific activity was 4.21 U/mg. The molecular weight of cellulase is 63 kDa as indicated by SDS-PAGE and zymogram. Its maximum activity was achieved at 60 °C and pH 5.0. In addition, it showed outstanding thermo-tolerance as it could retain its full activity after a 12-h incubation at 90 °C.

Anthracnose disease, caused by the Colletotrichum gloeosporioides species, affects vegetables, fruits, pulses, and cereals, leading to significant economic losses worldwide. Although many synthetic fungicides are used to control this pathogen, eco-friendly biological alternatives are gaining popularity. This study focuses on isolating and purifying chitinase ( Af Chi)from a marine bacterium and testing its antifungal efficacy against C. gloeosporioides spore germination by targeting the chitin in the fungal cell wall. The chitinase was purified from a marine bacterium A. faecalis from the Arabian Sea and had a molecular mass of 45 kDa and a specific activity of 84.6 U/mg. Af Chi worked best at 50 °C and pH 7.0 in Tris HCl buffer. Na⁺ ion was the highest cofactor, highlighting the halophilic nature of this chitinase. K⁺, Ca²⁺, Cu²⁺, Mg²⁺, Mn²⁺, and EDTA also increased activity, while Fe³⁺, Zn²⁺, Co²⁺, and Pb²⁺ decreased it. The K_m and V_max values were 1.87 µg/mL and 17.45 U/mL, respectively. Purified Af Chi at 10 mg/mL completely inhibited spore germination within 8 h and reduced the size of the spores.

The study was conducted on 60 L of suckling piglets out of 775 piglets, of which 227 piglets had diarrhea litres of piglets, and out of 775 piglets, 227 piglets had diarrhoea syndrome. There were 3 interventions in separate trials as follows: 1 and 2 involved antibiotic use (Enrofloxacin and Gentamicin); Trial 3 used the supplement Lectin C (LvCLT3 and LvCLT4) for a treatment period of 3-7 days. Intervention results on 227 piglets with diarrhea showed the highest cure rate when supplemented with Lectin C, with no mortality rate, longer treatment time, and no reinfection rate. While the two antibiotic trials still had lower cure rates, mortality and reinfection rates were higher. After 05 days of recovery, piglets were tested for MCV, MCH, and MCHC, showing an apparent decrease in the group supplemented with Lectin C, while the two groups using antibiotics still had high rates, with a confidence level of P < 0.05; 0.01 and 0.001. Antibiotics treat piglets in their early stages, so there is a risk of immunodeficiency and low infection response. It is necessary to supplement substances derived from dietary supplements. Supplementing Lectin C increases resistance, enhances immune response, improves the effectiveness of treating diarrhoea syndrome in piglets, and ensures safe meat quality in the future. Lectin C supplementation will improve piglet health and breed quality efficiency. This heralds a promising future for the pig industry with improved meat quality and reduced environmental impact.