Search

Objective To explore the impact of herpes simplex virus type 1 (HSV-1) mutant strain M6 on macrophage-mediated immune responses after infecting human bronchial epithelial cells (16HBE cells). Methods, HSV-1 infection of 16HBE cells was conducted to assess cytokine alterations in the culture medium; Macrophages were co-cultured with supernatants from HSV-1-infected 16HBE cells and subsequently reintroduced into mice via tail vein infusion. Cytokine expression levels in mouse lymph nodes, changes in spleen T cell proportions, mouse neutralizing antibody levels, and specific T cell responses were measured on days 1, 3, 7, 28, 56, and 90., Results Following infection of 16HBE cells with the HSV-1 mutant strain, cytokine expression in the supernatant, associated with macrophage recruitment and activation, was elevated, albeit slightly lower than that observed in the wild-type strain group. Following the tail vein infusion experiment, the mutant strain group exhibited temporal changes in the proportions of inflammatory factors, chemokines, and T cells within the mouse lymph nodes, resulting in weaker humoral immunity compared to the wild-type strain group, yet eliciting stronger specific T cell responses, with only a few parameters showing significant differences from the wild-type strain group (P < 0.05). Conclusion 16HBE cells infected with the HSV-1 mutant strain M6 can release cytokines that recruit and activate macrophages, allowing macrophages to carry specific activation information of the HSV-1 mutant strain, activating the host's immune system and inducing the host's Humoral immunity and cellular immunity. [ABSTRACT FROM AUTHOR]

As a pathogen, Photobacterium damselae subsp. damselae (PDD) is distributed widely in the marine environment, and the host species of PDD are diverse. Although in the past decade the number of reports on the pathogenicity of PDD to marine animals has gradually increased, it is necessary to study this further in order to establish targeted prevention and technical control measures to reduce harm to marine organisms. In this study, a high-virulence PDD strain (PDD1608) was selected to explore the effect of the virulence gene dly on the biological characteristics and pathogenicity. The dly-deleted mutant strain Δdly PDD1608::Cm was successfully constructed using the λRed recombination technique. The biological characteristics of the wild-type and mutant strains were compared, including growth, swarming motility, drug susceptibility, physiological and biochemical characteristics, biofilm formation ability, and hemolytic and phospholipase activity of extracellular products (ECP). Meanwhile, Oryzias melastigma was used as the target host, and the pathogenicity of wild-type and mutant strains and their ECPs to O.melastigma was detected by the artificial infection test. There was a positive correlation between the results of the bacterial solution and ECP challenge, indicating that deletion of the dly gene affects the virulence of the PDD strain. Deletion of the virulence gene dly resulted in slower growth of the PDD mutant strain; reduced swarming and hemolytic and phospholipase activity; no change in the drug susceptibility or physiological and biochemical characteristics of the wild type and mutant strains; compared with the wild type strain, significant different (P < 0.05) biofilm formation ability of the mutant strain; the artificial infection test showed that the pathogenicity of the mutant strain and its ECP decreased. The results of this study revealed that the virulence gene dly affects many biological characteristics of PDD strains, such as growth, swarming motility, and hemolytic and phospholipase activity, and it was found to be closely related to the pathogenicity of the PDD strain and ECP.The results of this study contribute to further study of the influence of the virulence gene dly on the biological characteristics of the PDD strain in order to determine the appropriate prevention and control measures to curtail its spread and infection. The artificial infection test of the model organism O.melastigma helps provide an animal reference model for further exploration of the pathogenic mechanism and infection process of the PDD strain on the host. The results of the ECP experiments provide a theoretical reference for the research and development of PDD subunit vaccines.

ABSTRACT: Quinoa (Chenopodium quinoa) has earned special attention worldwide due to its higher nutritional value and its adaptive ability to contrasting environments. Here, it was explored how quinoa seed germination is regulated. CqNLP1 gene was identified and cloned due to its higher expression level in quinoa seeds. The role of CqNLP1 in seed germination was studied based on model species as Arabidopsis sp. The function of NO3 - during seed germination of quinoa was analyzed. The results showed CqNLP1 gene can restore the germination rate of Arabidopsis mutant nlp8-1 and nlp8-2 strains, suggesting that CqNLP1 gene plays an important role in promoting seed germination. Appropriate level of NO3 - could improve the germination rate of quinoa seeds, promote the decomposition and utilization of soluble protein and ABA, increase the expression level of CqNLP1 and CYP707A2 during germination. The optimal NO3 - concentration to promote seed germination is 1mM.

Porcine pseudorabies has long existed in China and is a serious threat to the Chinese farming industry. To understand the prevalence and genetic variation of the porcine pseudorabies virus (PRV) and its pathogenicity in Yunnan Province, China, we collected 560 serum samples across seven Yunnan Province regions from 2020 to 2021 and detected anti-gE antibodies in these samples. Sixty-one clinical tissue samples were also collected from pigs with suspected PRV that were vaccinated with Bartha-K61. PRV-gE antibodies were found in 29.6% (166/560) of the serum samples. The PRV positivity rate in clinical tissue samples was 13.1% (8/61). Two isolates, PRV-KM and PRV-QJ, were obtained. The identity of the gB, gD, and gE genes between these isolates and the Chinese mutants exceeded 99.5%. These isolates and the classical Fa strain were used to infect 4-week-old rats intranasally to assess their pathogenicity. All infected rats showed the typical clinical and pathological features of PRV two days post-infection. The viral loads in the organs differed significantly among the infected groups. Viruses were detected in the saliva and feces at 12 h. Significant dynamic changes in total white blood cell counts (WBC), lymphocyte counts (Lym), and neutrophil counts (Gran) occurred in the blood of the infected groups at 24 and 48 h. These results show that mutant PRV strains are prevalent in Bartha-K61-vaccinated pigs in Yunnan Province, China. Moreover, rats shed PRV in their saliva and feces during early infection, indicating the need for rodent control in combatting PRV infections in Yunnan Province, China. [ABSTRACT FROM AUTHOR]

Porcine pseudorabies has long existed in China and is a serious threat to the Chinese farming industry. To understand the prevalence and genetic variation of the porcine pseudorabies virus (PRV) and its pathogenicity in Yunnan Province, China, we collected 560 serum samples across seven Yunnan Province regions from 2020 to 2021 and detected anti-gE antibodies in these samples. Sixty-one clinical tissue samples were also collected from pigs with suspected PRV that were vaccinated with Bartha-K61. PRV-gE antibodies were found in 29.6% (166/560) of the serum samples. The PRV positivity rate in clinical tissue samples was 13.1% (8/61). Two isolates, PRV-KM and PRV-QJ, were obtained. The identity of the gB, gD, and gE genes between these isolates and the Chinese mutants exceeded 99.5%. These isolates and the classical Fa strain were used to infect 4-week-old rats intranasally to assess their pathogenicity. All infected rats showed the typical clinical and pathological features of PRV two days post-infection. The viral loads in the organs differed significantly among the infected groups. Viruses were detected in the saliva and feces at 12 h. Significant dynamic changes in total white blood cell counts (WBC), lymphocyte counts (Lym), and neutrophil counts (Gran) occurred in the blood of the infected groups at 24 and 48 h. These results show that mutant PRV strains are prevalent in Bartha-K61-vaccinated pigs in Yunnan Province, China. Moreover, rats shed PRV in their saliva and feces during early infection, indicating the need for rodent control in combatting PRV infections in Yunnan Province, China.

O-acetyl-homoserine sulfhydrylase (OAHS) is a pyridoxal 5'-phosphate-dependent enzyme involved in microbial methionine biosynthesis, which catalyzes the conversion of o-acetyl-homoserine (OAH) to homocysteine. In our previous study, we found that OAHS of Streptococcus suis serotype 2 (SS2) can interact with the porcine blood-brain barrier (BBB) model, but whether OAHS regulates the penetration of BBB during SS2 infection is still unclear. To explore the role of OAHS in SS2 infection, OAHS-deficient SS2 mutant strain (SC19-ΔOAHS) and gene complemental strain (SC19-cΔOAHS) were constructed. Compared to the parent strain, with the loss of oahs , the chain length of SC19-ΔOAHS was shortened, the virulence was significantly reduced, the survival rate of mice infected with SC19-ΔOAHS was obviously increased accompanied by the relieved clinical symptoms. And the survival ability of SC19-ΔOAHS in whole blood was also remarkably decreased. Interestingly, the adhesion of SC19-ΔOAHS to endothelial cells was markedly increased, but the deficiency of OAHS significantly inhibited the strain penetrating BBB both in vivo and in vitro. Most of these phenomena can be reversed by the complemental strain (SC19-cΔOAHS). Further study showed that the deficiency of OAHS severely reduced SC19-induced endothelial cell apoptosis, tight junctions (TJs) protein impairment and the expression of SS2 virulence factor Enolase (Eno), involved in the destruction of BBB. Additionally, SC19-ΔOAHS immunized mice were able to resist SC19 or JZLQ022 infection. In conclusion, we confirmed that OAHS promoted the pathogenicity by enhancing host's BBB permeability and immune escape, and SC19- ΔOAHS is a potential live vaccine. ● The importance of OAHS to the virulence of SS2 was revealed. ● For the first time, we found that OAHS is associated with SS2-induced blood-brain barrier destruction. ● SC19-ΔOAHS has potential as a live vaccine. The mice immunized with SC19-ΔOAHS are able to resist homotype infection. [ABSTRACT FROM AUTHOR]