Screening candidate genes for fruit size based on QTL-seq in Chinese jujube.

Introduction: Fruit size is an important economic trait affecting jujube fruit quality, which has always been the focus of marker-assisted breeding of jujube traits. However, despite a large number of studies have been carried out, the mechanism and key genes regulating jujube fruit size are mostly unknown. Methods: In this study, we used a new analysis method Quantitative Trait Loci sequencing (QTL-seq) (bulked segregant analysis) to screen the parents 'Yuhong' and 'Jiaocheng 5' with significant phenotypic differences and mixed offspring group with extreme traits of large fruit and small fruit, respectively, and, then, DNA mixed pool sequencing was carried out to further shortening the QTL candidate interval for fruit size trait and excavated candidate genes for controlling fruit size. Results: The candidate intervals related to jujube fruit size were mainly located on chromosomes 1, 5, and 10, and the frequency of chromosome 1 was the highest. Based on the QTL-seq results, the annotation results of ANNOVAR were extracted from 424 SNPs (single-nucleotide polymorphisms) and 164 InDels (insertion-deletion), from which 40 candidate genes were selected, and 37 annotated candidate genes were found in the jujube genome. Four genes (LOC107428904, LOC107415626, LOC125420708, and LOC107418290) that are associated with fruit size growth and development were identified by functional annotation of the genes in NCBI (National Center for Biotechnology Information). The genes can provide a basis for further exploration and identification on genes regulating jujube fruit size. Discussion: In summary, the data obtained in this study revealed that QTL intervals and candidate genes for fruit size at the genomic level provide valuable resources for future functional studies and jujube breeding.

The Influences of Soil and Meteorological Factors on the Growth and Fruit Quality of Chinese Jujube (Ziziphus jujuba Mill.).

Chinese jujube (Ziziphus jujuba Mill.) is attracting more and more attention worldwide due to their tasty and nutritious fruit with extremely high contents of vitamin C (Vc) and soluble sugar. In order to find out the main factors that influence jujube growth and reproductive adaptability, the phenological periods, vegetative growths, fruiting abilities, and fruit qualities of eight newly released cultivars were compared and comprehensively analyzed in three representative ecological sites of the three main jujube-producing regions including Fuping (Hebei), Taigu (Shanxi), and Alar (Xinjiang) in China. Our results showed that the characteristics of jujube cultivars were significantly affected by soil and meteorological factors. The fruit number per bearing shoot was much more affected by temperature, light, and rainfall. The fruit number per bearing shoot, contents of soluble solids, and soluble sugar and Vc contents in fruits were influenced more by meteorological factors. The content of flavonoids was affected by both soil and meteorological factors. A principal component analysis (PCA) indicated that cultivars suitable for planting in Fuping (Hebei) were Yuhong and Lengbaiyu. Zaocuimi, Fucuimi, and Zaoqiuhong were suitable to be cultivated in Taigu (Shanxi), while Zaocuimi, Yuhong, Yulu, Luzao 2, and Yueguang behaved better in Alar (Xinjiang). This study provides insights of the environmental factors on jujube yield and quality and therefore provides references for highly efficient jujube cultivation.

A Rare Case of Neuralgic Amyotrophy Associated with Brucella Infection.

Multiple micro-organisms associated with Neuralgic Amyotrophy (NA) have been reported and Brucella species should be an important and overlooked infectious cause or trigger.We report a rare case of neuralgic amyotrophy associated with Brucella infection and is believed to be the first such case report in China. A 42-year-old male with brucellosis was confirmed serologically, who presented recurrent fever and fatigue and suddenly developed severe pain in the right shoulder within one week, followed by the inability to lift and abduct the proximal end of the right upper limb. Based on typical clinical manifestions, MRI neuroimaging of the brachial plexus and neuro-electrophysiological studies to confirm a diagnosis of NA and presented spontaneous recovery during this period, immunomodulatory treatment with corticosteroid or intravenous immunoglobulin had not been attempted, leaving a serious movement disorder in the right upper limb. Even rare, NA and other neurobrucellosis forms should be considered as complications of Brucella infection.

Construction of a highly saturated genetic map and identification of quantitative trait loci for leaf traits in jujube.

Chinese jujube (Ziziphus jujuba Mill.), a member of the genus Ziziphus, which comes under the family Rhamnaceae, is the most important species in terms of its economic, ecological, and social benefits. To dissect the loci associated with important phenotypical traits and analyze their genetic and genomic information in jujube, a whole-genome resequencing (WGR) based highly saturated genetic map was constructed using an F1 hybrid population of 140 progeny individuals derived from the cross of 'JMS2' × 'Jiaocheng 5'. The average sequencing depth of the parents was 14.09× and that of the progeny was 2.62×, and the average comparison efficiency between the sample and the reference genome was 97.09%. Three sets of genetic maps were constructed for a female parent, a male parent, and integrated. A total of 8,684 markers, including 8,158 SNP and 526 InDel markers, were evenly distributed across all 12 linkage groups (LGs) in the integrated map, spanning 1,713.22 cM with an average marker interval of 0.2 cM. In terms of marker number and density, this is the most saturated genetic map of jujube to date, nearly doubling that of the best ones previously reported. Based on this genetic map and phenotype data from 2019 to 2021, 31 leaf trait QTLs were identified in the linkage groups (LG1, 15; LG3, 1; LG5, 8; LG7, 4; LG8, 1, and LG11, 2), including 17 major QTLs. There were 4, 8, 14, and 5 QTLs that contributed to leaf length, leaf width, leaf shape index, and leaf area, respectively. Six QTLs clusters were detected on LG1 (8.05 cM-9.52 cM; 13.12 cM-13.99 cM; 123.84 cM-126.09 cM), LG5 (50.58 cM-50.86 cM; 80.10 cM-81.76 cM) and LG11 (35.98 cM-48.62 cM). Eight candidate genes were identified within the QTLs cluster regions. Annotation information showed that 4 genes (LOC107418196, LOC107418241, LOC107417968, and LOC112492570) in these QTLs are related to cell division and cell wall integrity. This research will provide a valuable tool for further QTL analysis, candidate gene identification, map-based gene cloning, comparative mapping, and marker-assisted selection (MAS) in jujube.

Modulation effect of chenpi extract on gut microbiota in high-fat diet-induced obese C57BL/6 mice.

The current study employed high-fat diet (HFD) induced murine model to assess the relationship between the lipid-lowering effect of aged citrus peel (chenpi) extract and the alterations of gut microbiota. The results showed that intake of chenpi extract for 12 week dose-dependently suppressed HFD-induced body weight, food intake, Lee's index, together with decreased the level of fasting blood glucose, total cholesterol, triglyceride, and low-density lipoprotein cholesterol. Moreover, chenpi extract administration up-regulated the abundance and diversity of fecal microbiota and down-regulated the ratio of Firmicutes-to-Bacteroidetes, which was characterized by the lower family of Lachnospiraceae, Helicobacteraceae, and Desulfovibrionaceae, and higher family of Bacteroidales_S24-7, Bacteroidaceae, Rikenellaceae, and Ruminococcaceae. Consistently, at the genus levels, chenpi extract treatment reversed the expansions of Helicobacter, Lachnospiraceae_UCG-006, and Desulfovibrio, while increased the abundance of Bacteroides, Rikenellaceae_RC9_gut_group, and Alistipes (belonging to Rikenellaceae family), Anaerotruncus and Odoribacter (belonging to Ruminococcaceae family), which were significantly negatively correlated with the levels of the serum lipid parameters. In conclusion, our findings indicated that anti-obesity ability of chenpi extract might be related to the improvement of gut microbiota imbalance. PRACTICAL APPLICATIONS: With the improvement of living standards, the incidence of metabolic diseases such as obesity, hypertension, and diabetes has increased significantly, and it has become a public health problem that seriously affects the health of the people. Chenpi contains a large amount of active ingredients, flavonoids, and other compounds, which can promote the absorption of the digestive system and have good effects on diseases such as the cardiovascular system. Our previous study has confirmed that the chenpi extract effectively regulated the glucose and lipid metabolism disorder induced by high-fat diet. However, it is not clear whether the effect is closely related to the improvement of gut microbiota. Accordingly, our result would provide a theoretical basis for future research on the relationship between obesity, chenpi extract, and gut microbiota, and support additional understanding of its potential anti-obesity effects.

Distinct Gut Microbiota and Metabolite Profiles Induced by Different Feeding Methods in Healthy Chinese Infants.

Human milk is closely correlated with infant gut microbiota and is important for infant development. However, most infants receive exclusively insufficient breast milk, and the discordance between effects of commercial formula and human milk exists. To elucidate the differences induced by various feeding methods, we determined microbiota and metabolites composition in fecal samples from 77 healthy infants in Northeast China and identified the differences in various feeding methods. Bacterial 16S rRNA gene sequence analysis demonstrated that the fecal samples of exclusively breastfed (BF) infants were abundant in Bifidobacterium and Lactobacillus; the mixed-fed (MF) infants had the highest abundance of Veillonella and Klebsiella; the exclusively formula-fed (FF) infants were enriched in Bacteroides and Blautia; and the complementary food-fed (CF) infants were associated with higher relative abundance of Lachnoclostridium and Akkermansia. Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics data revealed that the fecal samples of BF infants had the highest abundance of dl-citrulline, threonine, l-proline, l-glutamine, guanine, and l-arginine; the MF infants were abundant in d-maltose, stearidonic acid, capric acid, and myristic acid; the FF infants were enriched in itaconic acid, 4-pyridoxic acid, prostaglandin B2, thymine, dl-α-hydroxybutyric acid, and orotic acid; and the CF infants were associated with higher relative abundance of taurine, l-tyrosine, adenine, and uric acid. Furthermore, compared with the BF infants, the MF and FF infants were more abundant in fatty acid biosynthesis. Collectively, these findings will provide probable explanations for some of the risks and benefits related to infant feeding methods and will support a theoretical basis for the development of infant formula.

Milk fermented with Lactococcus lactis KLDS4.0325 alleviates folate status in deficient mice.

Folate is an essential B vitamin and its deficiency is common in many parts of the world. Natural folate produced by microorganisms may be an alternative to chemically synthesized folic acid (FA) as a dietary supplement. Previously, two lactic acid bacteria (LAB) strains, a high folate-producing Lactococcus lactis subsp. lactis KLDS4.0325 and a weak folate-producing Lactococcus lactis subsp. lactis KLDS4.0613, were identified. The aim of this study was to evaluate the effect of milk fermented with L. lactis KLDS4.0325 (folate-enriched fermented milk, FEFM) in alleviating folate deficiency status using murine folate deficiency models. In addition, the link between gut microbiota diversity and folate levels in mice was investigated. Results showed that FEFM increased FA and 5-methyltetrahydrofolate (5-MTHF) concentrations in the whole blood and liver, and decreased plasma homocysteine (Hcy) levels. 16S rDNA sequence analysis also revealed that the supplementation of FEFM (containing 0.6 µg mL-1 folate) and 0.6 µg d-1 FA (FEFM + LFA) significantly improved the poor status of the gut microbiota composition caused by folate deficiency, and the effect was better than that with 1.2 µg d-1 FA (HFA) supplementation. Our findings show that FEFM can be used as a folate-fortified food to alleviate folate deficiency effectively. In addition, it may be considered as a partial or total replacement for synthetic FA.

Probiotic Mixture of Lactobacillus plantarum Strains Improves Lipid Metabolism and Gut Microbiota Structure in High Fat Diet-Fed Mice.

The global prevalence of obesity is rising year by year, which has become a public health problem worldwide. In recent years, animal studies and clinical studies have shown that some lactic acid bacteria possess an anti-obesity effect. In our previous study, mixed lactobacilli (Lactobacillus plantarum KLDS1.0344 and Lactobacillus plantarum KLDS1.0386) exhibited anti-obesity effects in vivo by significantly reducing body weight gain, Lee's index and body fat rate; however, its underlying mechanisms of action remain unclear. Therefore, the present study aims to explore the possible mechanisms for the inhibitory effect of mixed lactobacilli on obesity. C57BL/6J mice were randomly divided into three groups including control group (Control), high fat diet group (HFD) and mixed lactobacilli group (MX), and fed daily for eight consecutive weeks. The results showed that mixed lactobacilli supplementation significantly improved blood lipid levels and liver function, and alleviated liver oxidative stress. Moreover, the mixed lactobacilli supplementation significantly inhibited lipid accumulation in the liver and regulated lipid metabolism in epididymal fat pads. Notably, the mixed lactobacilli treatment modulated the gut microbiota, resulting in a significant increase in acetic acid and butyric acid. Additionally, Spearman's correlation analysis found that several specific genera were significantly correlated with obesity-related indicators. These results indicated that the mixed lactobacilli supplementation could manipulate the gut microbiota and its metabolites (acetic acid and butyric acid), resulting in reduced liver lipid accumulation and improved lipid metabolism of adipose tissue, which inhibited obesity.

Lactobacillus acidophilus alleviates type 2 diabetes by regulating hepatic glucose, lipid metabolism and gut microbiota in mice.

Diabetes, an endocrine and metabolic disorder, has become the third most non-infectious chronic disease that threatens human health. Type 2 diabetes (T2D) accounts for more than 90% of diabetic patients, mainly caused by environmental factors. Lactic acid bacteria (LAB) exhibit several health benefits to the host including regulating glucose and lipid metabolism and improving oxidative stress and inflammatory response. However, the anti-diabetic mechanism of probiotics has not been elucidated clearly. In this study, the anti-diabetic effects of Lactobacillus acidophilus KLDS1.1003 and KLDS1.0901 on T2D mice were assessed. Oral administration of L. acidophilus KLDS1.1003 and KLDS1.0901 for 6 weeks significantly improved the epithelial barrier function, which in turn lowered inflammation cytokines, including IL-8, TNF-α and IL-1ß in liver and colon tissue, and prevented liver and colon tissue injuries to some extent. Additionally, L. acidophilus treatment regulated the expression genes that are related to glucose and lipid metabolism. The two tested strains down-regulated the expression of glycogen synthase kinase 3ß (GSK-3ß), fatty acid synthase (FAS) and sterol regulatory element-binding transcription factor 1c (SREBP-1c), and up-regulated the expression of protein kinase B (Akt). However, L. acidophilus KLDS1.0901 is better for improving T2D than L. acidophilus KLDS1.1003. Further research showed that L. acidophilus KLDS1.0901 supplementation could reshape gut microbiota, increasing short chain fatty acid-producing bacteria (Blautia, Roseburia and Anaerotruncus) and the level of SCFAs and decreasing the relative abundance of Gram-negative bacteria such as Desulfovibrio, Alistipes and Bacteroides. Notably, L. acidophilus KLDS1.0901 treatment restored the structure of gut microbiota similar to the control group. These findings suggested that L. acidophilus KLDS1.0901 might be used as a new type of antidiabetic drug candidate.

Screening for Potential Novel Probiotics With Dipeptidyl Peptidase IV-Inhibiting Activity for Type 2 Diabetes Attenuation in vitro and in vivo.

Diabetes has become the second most severe disease to human health. Probiotics are important for maintaining gastrointestinal homeostasis and energy balance and have been demonstrated to play a positive role in the prevention and treatment of metabolic syndromes, such as obesity, inflammation, dyslipidemia, and hyperglycemia. The objective of this study was to screen potential antidiabetic strains in vitro and evaluate its effects in vivo. For the in vitro section, dipeptidyl peptidase IV (DPP-IV) inhibitory and antioxidant activities of 14 candidate Lactobacillus spp. strains were tested. Then hydrophobicity and acid and bile salt tolerance assays were determined. The most promising in vitro strain was further evaluated for its antidiabetic properties in vivo using type 2 diabetes mice induced by high-fat diet and intraperitoneal injection of streptozotocin (STZ). The reference strain for this study was Lactobacillus rhamnosus GG. Results showed that cell-free excretory supernatants and cell-free extracts of Lactobacillus acidophilus KLDS1.0901 had better DPP-IV inhibitory activity, antioxidative activities, and biological characteristics than other strains. At the end of the treatment, we found that L. acidophilus KLDS1.0901 administration decreased the levels of fasting blood glucose (FBG), glycosylated hemoglobin, insulin in serum and AUCglucose, and increased the level of glucagon-like peptide 1 in serum compared with diabetic mice (p < 0.05). Moreover, L. acidophilus KLDS1.0901 supplementation increased the activities of superoxide dismutase, glutathione peroxidase, the level of glutathione, and reduced the level of malondialdehyde in serum. These results indicated that L. acidophilus KLDS1.0901 could be used as a potential antidiabetic strain; its application as food supplement and drug ingredient is thus recommended.

Complete genome sequence of Enterococcus durans KLDS6.0933, a potential probiotic strain with high cholesterol removal ability.

BACKGROUND: Enterococci are commensal bacteria in the mammalian gastrointestinal tract which play an important role in the production of various fermented foods. Thus, certain enterococcal strains are commonly used as probiotics to confer health benefits to human and animals. Enterococcus durans KLDS6.0933 is a potential probiotic strain with high cholesterol removal ability, which was isolated from traditional naturally fermented cream in Inner Mongolia of China. To better understand the genetic basis of the probiotic properties of this strain, the whole-genome sequence was performed using the PacBio RSII platform. RESULTS: Enterococcus durans KLDS6.0933 contains a circular chromosome of 2,867,028 bp, two plasmids of 163,286 bp and 41,490 bp, respectively. Within the 2704 predicted genes, genes involved with acid, bile and oxidative stress resistance were identified. Bile salt hydrolase (BSH, LIANG_RS13510), a cholesterol removal enzyme identified in the E. durans KLDS6.0933 genome is different from that of other Enterococcus strains. Furthermore, unlike other Enterococcus strains, E. durans KLDS 6.0933 can facilitate the complete biosynthesis pathway of l-tryptophan. CONCLUSIONS: In silico analysis confirmed the probiotic properties of E. durans KLDS6.0933 and may help us exploit the potential applications of E. durans KLDS6.0933 as an industrially important strain.

Safety Assessment of Lactobacillus helveticus KLDS1.8701 Based on Whole Genome Sequencing and Oral Toxicity Studies.

Lactobacillus helveticus KLDS1.8701 isolated from Chinese traditional fermented dairy product has been shown earlier to possess probiotic potentials but it is important to evaluate its safety in view of its possible use as a probiotic. The aim of the present study is to critically assess the safety of L. helveticus KLDS1.8701 through multiple perspectives. The complete genome of L. helveticus KLDS1.8701 was sequenced to mine for safety-associated genes. The minimum inhibitory concentrations of 15 antimicrobials and the adverse metabolites were determined. Standard acute oral and subacute toxicity studies were conducted in rats. The results in silico disclosed that the genome of L. helveticus KLDS1.8701 carries no transferable antibiotic resistance genes, no virulence factors and only 3 genes related to adverse metabolites. In vitro results showed that L. helveticus KLDS1.8701 was resistant against 6 antimicrobials and did not raise safety concerns about biogenic amine, D-lactic acid and nitroreductase. The results in vivo revealed that no adverse effects on experimental rats were observed in the oral toxicity tests. Overall, findings from this study suggest that L. helveticus KLDS1.8701 is safe and can be used as a potential probiotic for human consumption.