Identification of Volatile Organic Compounds Produced by Xenorhabdus indica Strain AB and Investigation of Their Antifungal Activities.

Xenorhabdus spp. are symbiotic bacteria associated with entomopathogenic nematodes to form a model complex that is used for the biological control of insect pests. These bacteria also produce secondary metabolites that have commercial potential in the pharmaceutical and agroforestry industries. Volatile organic compounds (VOCs) produced by the Xenorhabdus indica "strain AB" have been shown to have significant antifungal activity against Fusarium oxysporum f. sp. cucumerinum. Using gas chromatography-mass spectrometry, we identified 61 volatiles in the mixture of VOCs emitted by strain AB compared to a control strain, 6 of which were investigated for their antifungal activities. Of these, methyl anthranilate exhibited the highest mycelial growth suppression toward F. oxysporum, with a minimum inhibitory volume (MIV) of 50 µL/plate. Fluorescence assays, scanning electron microscopy, and measurements of the leakage of intracellular components revealed that the use of methyl anthranilate changed cell wall and cell membrane integrity as well as the permeability of the plasma membrane. Furthermore, methyl anthranilate treatment upregulated the transcription level of target genes related to redox reactions and the cell wall integrity pathway. The results suggest a novel mechanism used by Xenorhabdus spp. to overcome competitors during its life cycle and open up a new approach to using these bacteria in biological control. IMPORTANCE Fungal phytopathogens, particularly Fusarium oxysporum, are a major problem worldwide, especially in the postharvest of vital economic crops. Concerns about negative effects on the environment and human health have led to increasing restrictions on the use of chemical fungicides, and therefore, biological control agents are now being considered alternatives. It is in this context that we investigated the antifungal activity of VOCs produced by X. indica strain AB against F. oxysporum. We found that AB VOCs have a strong effect on the growth of the fungal phytopathogen. In addition, 85% of the identified volatile compounds were determined to be new compounds, opening up new lines of research to discover their properties, effects, and potential for pharmaceutical and agricultural applications. Antifungal assays proved that four of the six compounds with a high concentration in the GC-MS profile had a significant inhibitory effect on pathogen growth. Accordingly, this study opens up a new approach for the use of these bacteria in biocontrol.

Potential antimicrobial activity of camel milk as a traditional functional food against foodborne pathogens in vivo and in vitro.

Foodborne pathogens are a leading cause of mortality worldwide. Therefore, strategies focused on functional foods are urgently required to tackle this issue. As a result, camel milk is one of the most important traditional functional foods since it contains a variety of bioactive components, which all have antimicrobial activity against foodborne pathogens. The study aims to investigate the potential antimicrobial activity of raw camel milk against foodborne pathogens in both in vitro agar well diffusion and infected mice, especially Listeria monocytogenes, Staphylococcus aureus, Salmonella Typhimurium and Escherichia coli, particularly in societies that rely on consuming camel milk in its raw form. A total of eighty C57BL/6 mice were divided into ten groups and gavaged with or without camel milk for two consecutive weeks. A blood plasma analysis and serum insulin levels were measured. Histological investigations of the liver, pancreas, kidney, spleen, lung and testicles were also performed. In both in vivo and in vitro studies when compared to other pathogenic bacteria, E. coli was the most affected by raw camel milk, with a significant clear zone of 2.9 ± 0.13 cm in vitro and in all measured parameters in vivo (p < 0.05). As a result, we advocated for further research to improve camel breeding, raise milk yield and extend its reproductive capability as one of the most important farm animals.

Effect of Spirulina platensis Supplementation on Carcass Characteristics, Fatty Acid Profile, and Meat Quality of Omani Goats.

In a 70-day study, 36 Jabbali and Sahrawi bucks, aged 11 months, were utilized to evaluate the effects of different levels of spirulina dietary supplement (SP) on carcass characteristics, fatty acid profile, and meat quality traits in Omani goat breeds. The goats were put into six groups of six bucks, each at random. The diet consisted of a conventional concentrate feed ration (CFR) without spirulina (CON), and the CFR diet supplemented with spirulina at the levels of 2 g/head daily (T1) and 4 g/head daily (T2). In general, Sahrawi bucks showed a highly significant response to SP feeding compared with Jabbali bucks. The treatment groups, especially T1, showed a significant increase in average daily gain and carcass traits (body length, leg length, and the rack weight) compared with the CON group of Sahrawi bucks. The weights of omental and kidney fat were also significantly higher in T1 compared with CON and T2 groups of Sahrawi goats, while they were significantly higher in T2 compared with CON and T1 groups of Jabbali goats. Carcass profile and meat quality, including ultimate ph and meat color lightness (L*) were increased significantly with dietary spirulina in both LD and SM muscles of Sahrawi goats. Most of the Sfa, Mufa, Pufa, Pufa n-6, Pufa n-3, and n-6/n-3 ratios of the LD showed significant differences in diets supplemented with SP compared with CON for Sahrawi bucks, while some of them were significant in Jabbali bucks. The LD muscle of Sahrawi goats fed diets supplemented with SP of the T1 group significantly decreased in the amounts of pentadecanoic and margaric acids compared with the T2 and CON groups. The study concluded that incorporating SP (2 g and 4 g/head daily) into the diet of Omani goats, especially Sahrawi goats, can increase growth performance, as well as improve fatty acid composition and meat quality.

ACAT2 Is a Novel Negative Regulator of Pig Intramuscular Preadipocytes Differentiation.

Intramuscular fat (IMF) is considered as the fat deposited between muscle fibers. The extracellular matrix microenvironment of adipose tissue is of critical importance for the differentiation, remodeling and function of adipocytes. Therefore, in this study we extracted the muscle tissue centrifugal fluid (MTF) of the longissimus dorsi of Erhualian pigs to mimic the microenvironment of intramuscular pre-adipocytes. MTF of pigs with low intramuscular fat level can inhibit pig intramuscular pre-adipocytes differentiation. Then, proteomics technology (iTRAQ) was used to analyze the MTF with different IMF content, and it was found that individuals with high IMF had low ACAT2 (Acyl-CoA: cholesterol acyltransferases 2) levels, while individuals with low IMF had high ACAT2 levels. Significant changes took place in the pathways involved in coenzyme A, which are closely related to fat and cholesterol metabolism. Therefore, we speculate that ACAT2, as an important element involved in cholesterol metabolism, may become a potential molecular marker for the mechanism of pig intramuscular preadipocytes differentiation. Overexpression of ACAT2 in pig intramuscular pre-adipocytes can inhibit their differentiation, while adding ACAT2 inhibitor avasimibe can rescue the process. Knockdown of srebp2 or ldlr, which are two key genes closely related to ACAT2 and cholesterol metabolism, can inhibit pig intramuscular pre-adipocytes differentiation. Overall, our results suggest that ACAT2 is a novel negative regulator of intramuscular adipocyte differentiation through regulation of pparγ, cebpα signaling and srebp2/ldlr signaling involved in cholesterol metabolism.

A novel c.-652C>T mutation in UCHL1 gene is associated with the growth performance in Yangzhou goose.

As a member of the ubiquitin-dependent proteasome degradation pathway, Ubiquitin carboxyl-terminal hydrolase-L1 (UCHL1) plays a key role in post-translational modification and protein degradation, and it is extensive and important for the regulation of various biological functions of the organism. However, its function remains unclear in goose growth performance. In this study, the full-length genomic DNA and coding region of UCHL1 gene was firstly cloned and characterized in Yangzhou goose. Tissue expression profile revealed that UCHL1 was exclusively expressed in brain and gonads. A novel single nucleotide polymorphisms c.-652C>T which is significantly related to 64-d body weight of Yangzhou goose was found in UCHL1 promoter region by comparative sequencing. Correlation analysis in a population of 405 geese showed that TT genotype individuals had higher body weight than CC individuals in male, but not in female geese. Dual-luciferase reporter assay indicated that the single nucleotide polymorphisms c.-652C>T is located at the core promoter region of UCHL1, and the promoter transcription activity was significantly increased (P < 0.01) when allele C changed to T. Geese with TT genotype had higher mRNA level of UCHL1 in brain tissue than those of CC genotype (P < 0.01). Compared with CC individuals, neuropeptide Y and AdipoR1 mRNA level was significantly higher in TT individuals (P < 0.05), while FAS mRNA level was lower in the TT individuals (P < 0.05). In summary, we identify a novel mutation in the promoter of UCHL1 gene, which can alter transcriptional activity of UCHL1 gene, and affect the growth performance of male goose.

Identification and Validation of Marketing Weight-Related SNP Markers Using SLAF Sequencing in Male Yangzhou Geese.

Growth performance is a complex economic trait for avian production. The swan goose (Anser cygnoides) has never been exploited genetically like chickens or other waterfowl species such as ducks. Traditional phenotypic selection is still the main method for genetic improvement of geese body weight. In this study, specific locus amplified fragment sequencing (SLAF-seq) with bulked segregant analysis (BSA) was conducted for discovering and genotyping single nucleotide polymorphisms (SNPs) associated with marketing weight trait in male geese. A total of 149,045 SNPs were obtained from 427,093 SLAF tags with an average sequencing depth of 44.97-fold and a Q30 value of 93.26%. After SNPs' filtering, a total of 12,917 SNPs were included in the study. The 31 highest significant SNPs-which had different allelic frequencies-were further validated by individual-based AS-PCR genotyping in two populations. The association between 10 novel SNPs and the marketing weight of male geese was confirmed. The 10 significant SNPs were involved in linear regression model analysis, which confirmed single-SNP associations and revealed three types of SNP networks for marketing weight. The 10 significant SNPs were located within or close to 10 novel genes, which were identified. The qPCR analysis showed significant difference between genotypes of each SNP in seven genes. Developed SLAF-seq and identified genes will enrich growth performance studies, promoting molecular breeding applications to boost the marketing weight of Chinese geese.

Screening Potential Probiotic Characteristics of Lactobacillus brevis Strains In Vitro and Intervention Effect on Type I Diabetes In Vivo.

Diabetes has become the third most serious threat to human health, after cancer and cardiovascular disease. Notably, Lactobacillus brevis is the most common species of LAB that produces γ-aminobutyric acid (GABA). The aim of this study is to clarify the effect of time, strain types, antibiotic concentrations, different levels of pH, and intestinal juices in aerobic or anaerobic conditions and the effect of interactions between these factors on the potential properties of KLDS 1.0727 and KLDS 1.0373, furthermore, antagonistic activity against foodborne pathogens. Moreover, another aim is to study the capability of KLDS 1.0727 and KLDS 1.0373 strains as gad gene carriers to express GABA that reduce the risk of type 1 diabetes in C57BL/6 mice as diabetic models. The obtained results exhibited the surprising tolerance of Lactobacillus brevis strains in vitro digestion models mimicking the conditions of the gastrointestinal tract, further, large antagonistic activity against foodborne pathogeneses. In vivo results displayed the significant effect on glucose level reduction, blood plasma, and histological assays of mice organs. As recommended, the use of Lactobacillus brevis strains should be widely shared in the market as a natural source of GABA in pharmaceutical and food applications.