Does canine inflammatory bowel disease influence gut microbial profile and host metabolism?

Background: Inflammatory bowel disease (IBD) refers to a diverse group of chronic gastrointestinal diseases, and gut microbial dysbiosis has been proposed as a modulating factor in its pathogenesis. Several studies have investigated the gut microbial ecology of dogs with IBD but it is yet unclear if this microbial profile can alter the nutrient metabolism of the host. The aim of the present study was to characterize the faecal bacterial profile and functionality as well as to determine host metabolic changes in IBD dogs. Twenty-three dogs diagnosed with IBD and ten healthy control dogs were included. Dogs with IBD were given a clinical score using the canine chronic enteropathy clinical activity index (CCECAI). Faecal short-chain fatty acids (SCFA) and ammonia concentrations were measured and quantitative PCR was performed. The concentration of plasma amino acids, acylcarnitines, serum folate, cobalamin, and indoxyl sulfate was determined. Results: No significant differences in the abundance of a selection of bacterial groups and fermentation metabolites were observed between the IBD and control groups. However, significant negative correlations were found between CCECAI and the faecal proportion of Lactobacillus as well as between CCECAI and total SCFA concentration. Serum folate and plasma citrulline were decreased and plasma valine was increased in IBD compared to control dogs. Increased plasma free carnitine and total acylcarnitines were observed in IBD compared with control dogs, whereas short-chain acylcarnitines (butyrylcarnitine + isobutyrylcarnitine and, methylmalonylcarnitine) to free carnitine ratios decreased. Dogs with IBD had a higher 3-hydroxyisovalerylcarnitine + isovalerylcarnitine to leucine ratio compared to control dogs. Conclusions: Canine IBD induced a wide range of changes in metabolic profile, especially for the plasma concentrations of short-chain acylcarnitines and amino acids, which could have evolved from tissue damage and alteration in host metabolism. In addition, dogs with more severe IBD were characterised by a decrease in faecal proportion of Lactobacillus

Host-microbe interactions in brine shrimp Artemia cultured under gnotobiotic and conventional rearing conditions

Host-microbe interaction plays an important role in mediating the fundamental physiological and immunological responses of the aquatic animals. However, in a conventional aquaculture system, it is difficult to determine the host-microbe interaction due to the interference by the natural microbiota in the rearing environment. In this thesis, we studied the host-microbe interaction induced by biotreatments such as probiotics and heat shock protein inducers by using a gnotobiotic brine shrimp Artemia larvae model system. In this thesis, we first established a simple and efficient protocol for the detection of gut resident bacteria of the larvae, facilitating the study of the host-microbe interaction. In the following chapters of the thesis, the direct effects of probiotics and heat shock protein inducer-Tex-OE® (Hspi) on the brine shrimp larvae and the microbes have been demonstrated respectively. The results showed that the probiotic strain LT3 and the Hspi could directly mediate the innate immune response of the larvae contributing to the tolerance against subsequential stressors. Besides the effects on the innate immune response of the larvae, the treatments of LT3 and Hspi were demonstrated to steer the gut microbiota of the larvae as well. In addition to the effect on the microbiota associated with the host, these treatments also influenced the behavior of the microbiota in the environment. The further study showed that the Hspi inoculated in the rearing water may stimulate the growth and the virulence factors production of the pathogen, leading to higher mortality of the larvae. In conclusion, the work presented in this thesis demonstrated that disease control strategies, such as probiotic administration and Hsp70 induction, can trigger the overall host-microbe interaction in every compartment of the aquaculture system

Enzymatic Characterization of Lytic Polysaccharide Monooxygenase TtLPMO9Y and Its Role in Juice Clarification and Cellulose Degradation

A novel lytic polysaccharide monooxygenase, TtLPMO9Y, was cloned and expressed from Thermothelomyces thermophilus. Its enzymatic properties were characterized, and its role in the degradation process of cellulose and pectin in plant cell walls was investigated. The results showed that the optimal reaction temperature and pH for TtLPMO9Y was 50 ℃ and 7, respectively. After treatment at 80 ℃ for 4 h, 63% of the enzyme activity remained, demonstrating good thermal stability. After treatment with TtLPMO9Y at 2, 4, 6, and 8 μmol/L combined with 1 mg/mL of pectinase, the clarity of fresh fruit juice increased by 4.9%–16.2% and the turbidity decreased 5.3%–21.0% when compared with pectinase alone. Furthermore, the combined use of 1, 3, and 5 μmol/L of TtLPMO9Y with cellulase increased the yield of reducing sugar from microcrystalline cellulose and corn straw by 21%–66% and 29%–91%, respectively, compared with cellulase alone. In conclusion, TtLPMO9Yhas good enzymatic properties and can effectively promote the degradation of cellulose and pectin in plant cell walls, demonstrating significant application value in juice processing

Probing the protective mechanism of poly-β-hydroxybutyrate against vibriosis by using gnotobiotic Artemia franciscana and Vibrio campbellii as host-pathogen model

The compound poly-beta-hydroxybutyrate (PHB), a polymer of the short chain fatty acid beta-hydroxybutyrate, was shown to protect experimental animals against a variety of bacterial diseases, (including vibriosis in farmed aquatic animals), albeit through undefined mechanisms. Here we aimed at unraveling the underlying mechanism behind the protective effect of PHB against bacterial disease using gnotobiotically-cultured brine shrimp Artemia franciscana and pathogenic Vibrio campbellii as host-pathogen model. The gnotobiotic model system is crucial for such studies because it eliminates any possible microbial interference (naturally present in any type of aquatic environment) in these mechanistic studies and furthermore facilitates the interpretation of the results in terms of a cause effect relationship. We showed clear evidences indicating that PHB conferred protection to Artemia host against V. campbellii by a mechanism of inducing heat shock protein (Hsp) 70. Additionally, our results also showed that this salutary effect of PHB was associated with the generation of protective innate immune responses, especially the prophenoloxidase and transglutaminase immune systems - phenomena possibly mediated by PHB-induced Hsp70. From overall results, we conclude that PHB induces Hsp70 and this induced Hsp70 might contribute in part to the protection of Artemia against pathogenic V. campbellii

The Relations between Chinese and English in the Era of Globalization

The authors study the ways to replenish the vocabulary of the modern Chinese language due to the penetration of English-American borrowings, adaptation/non-adaptation of the latter to the hieroglyphic environment, correlation of functional features of the English vocabulary and the intensity of replenishment of the vocabular

N-Acyl Homoserine Lactone-Degrading Bacillus sp. Improves the Survival of Penaeus vannamei Larvae Challenged with Vibrio harveyi

This study aimed to isolate AHL-degrading bacteria from the intestine of Penaeus vannamei and evaluate their ability to control pathogenic Vibrio harveyi in P. vannamei larvae. Twenty-seven isolates were obtained from the digestive tract of healthy Pacific white shrimp juveniles (P. vannamei) after six cycles of pasteurization at 70 ◦C, but only three isolates (E1LP2, E2LP1, and E2LP2) could degrade AHL. The 16S sequence results gave a high identity (>95%) with Bacillus sp. The isolates exhibited quorum-quenching abilities by degrading AHLs, thereby disrupting Vibrio quorum sensing and virulence. In Zoea and Mysis, the challenged larvae plus the administration of E1LP2 resulted in the lowest survival compared to the other groups. Isolates degrading N-acyl homoserine lactone improved the survival of shrimp Zoea and Mysis larvae when challenged with pathogenic V. harveyi. This is the first report on the use of quorum-sensing disrupter bacteria in P. vannamei larval shrimp culture. Our findings suggest that these Bacillus spp. strains have potential as biocontrol agents for sustainable shrimp aquaculture, reducing the reliance on antibiotics while mitigating vibriosis outbreaks

SARS-CoV-2 spike protein induces the cytokine release syndrome by stimulating T cells to produce more IL-2

IntroductionCytokine release syndrome (CRS) is one of the leading causes of mortality in patients with COVID-19 caused by the SARS-CoV-2 coronavirus. However, the mechanism of CRS induced by SARS-CoV-2 is vague.MethodsUsing spike protein combined with IL-2, IFN-γ, and TNF-α to stimulate human peripheral blood mononuclear cells (PBMCs) to secrete CRS-related cytokines, the content of cytokines in the supernatant was detected, and the effects of NK, T, and monocytes were analyzed.ResultsThis study shows that dendritic cells loaded with spike protein of SARS-CoV-2 stimulate T cells to release much more interleukin-2 (IL-2,) which subsequently cooperates with spike protein to facilitate PBMCs to release IL-1β, IL-6, and IL-8. These effects are achieved via IL-2 stimulation of NK cells to release tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), as well as T cells to release IFN-γ Mechanistically, IFN-γ and TNF-α enhance the transcription of CD40, and the interaction of CD40 and its ligand stabilizes the membrane expression of toll-like receptor 4 (TLR4) that serves as a receptor of spike protein on the surface of monocytes. As a result, there is a constant interaction between spike protein and TLR4, leading to continuous activation of nuclear factor-κ-gene binding (NF-κB). Furthermore, TNF-α also activates NF-κB signaling in monocytes, which further cooperates with IFN-γ and spike protein to modulate NF-κB–dependent transcription of CRS-related inflammatory cytokines.DiscussionTargeting TNF-α/IFN-γ in combination with TLR4 may represent a promising therapeutic approach for alleviating CRS in individuals with COVID-19

Idiopathic Male Infertility Is Strongly Associated with Aberrant Promoter Methylation of Methylenetetrahydrofolate Reductase (MTHFR)

Abnormal germline DNA methylation in males has been proposed as a possible mechanism compromising spermatogenesis of some men currently diagnosed with idiopathic infertility. Previous studies have been focused on imprinted genes with DNA methylation in poor quality human sperms. However, recent but limited data have revealed that sperm methylation abnormalities may involve large numbers of genes or shown that genes that are not imprinted are also affected.Using the methylation-specific polymerase chain reaction and bisulfite sequencing method, we examined methylation patterns of the promoter of methylenetetrahydrofolate reductase (MTHFR) gene (NG_013351: 1538-1719) in sperm DNA obtained from 94 idiopathic infertile men and 54 normal fertile controls. Subjects with idiopathic infertility were further divided into groups of normozoospermia and oligozoospermia. Overall, 45% (41/94) of idiopathic infertile males had MTHFR hypermethylation (both hemimethylation and full methylation), compared with 15% of fertile controls (P<0.05). Subjects with higher methylation level of MTHFR were more likely to have idiopathic male infertility (P-value for trend  = 0.0007). Comparing the two groups of idiopathic infertile subjects with different sperm concentrations, a higher methylation pattern was found in the group with oligozoospermia.Hypermethylation of the promoter of MTHFR gene in sperms is associated with idiopathic male infertility. The functional relevance of hypermathylation of MTHFR to male fertility warrants further investigation