DADS Inhibits the Proliferation of MDCC-MSB-1 Cells by Inducing Autophagy via the MEK/ERK Signalling Pathway.

Diallyl disulfide (DADS) is effective at suppressing tumour cell growth and proliferation. This study verified the morphology and growth activity of MDCC-MSB-1 cells by using an MTT assay to detect the effect of DADS on the proliferation of MDCC-MSB-1 cells and a CCK8 assay to detect the effect of DADS on the viability and proliferation of MDCC-MSB-1 cells. We found that the viability and proliferation of MDCC-MSB-1 cells decreased with increasing DADS concentrations. MDC staining and Western blotting were used to analyse autophagy, the associated protein LC3 and the MEK/ERK pathway proteins MEK and ERK and to investigate changes in cellular autophagy based on cell morphology and molecular biology. With increasing concentrations of DADS, MDCC-MSB-1 cell autophagy increased in a gradient manner. Additionally, the conversion of the autophagy marker protein LC3-I increased with increasing drug concentrations, and the relative expression of LC3-II steadily increased, as did the expression of key protein components of the MEK/ERK signalling pathway, including P-MEK1/2 and P-ERK1/2. These results suggest that DADS induces autophagy through the MEK/ERK pathway, thereby inhibiting the proliferation of MDCC-MSB-1 cells.

Thioredoxin A of Streptococcus suis Serotype 2 Contributes to Virulence by Inhibiting the Expression of Pentraxin 3 to Promote Survival Within Macrophages.

Streptococcus suis serotype 2 (SS2) is an important zoonotic pathogen that can infect humans in contact with infected pigs or their byproducts. It can employ different types of genes to defend against oxidative stress and ensure its survival. The thioredoxin (Trx) system is a key antioxidant system that contributes adversity adaptation and pathogenicity. SS2 has been shown to encode putative thioredoxin genes, but the biological roles, coding sequence, and underlying mechanisms remains uncharacterized. Here, we demonstrated that SSU05_0237-ORF, from a clinical SS2 strain, ZJ081101, encodes a protein of 104 amino acids with a canonical CGPC active motif and an identity 70-85% similar to the thioredoxin A (TrxA) in other microorganisms. Recombinant TrxA efficiently catalyzed the thiol-disulfide oxidoreduction of insulin. The deletion of TrxA led to a significantly slow growth and markedly compromised tolerance of the pathogen to temperature stress, as well as impaired adhesion ability to pig intestinal epithelial cells (IPEC-J2). However, it was not involved in H2O2 and paraquat-induced oxidative stress. Compared with the wild-type strain, the ΔTrxA strain was more susceptible to killing by macrophages through increasing NO production. Treatment with TrxA mutant strain also significantly attenuated cytotoxic effects on RAW 264.7 cells by inhibiting inflammatory response and apoptosis. Knockdown of pentraxin 3 in RAW 264.7 cells was more vulnerable to phagocytic activity, and TrxA promoted SS2 survival in phagocytic cells depending on pentraxin 3 activity compared with the wild-type strain. Moreover, a co-inoculation experiment in mice revealed that TrxA mutant strain is far more easily cleared from the body than the wild type strain in the period from 8-24 h, and exhibits significantly attenuated oxidative stress and liver injury. In summary, we reveal the important role of TrxA in the pathogenesis of SS2.

18F-fluorodeoxyglucose positron emission tomography-computed tomography scan after gastric endoscopy in those who present with non-specific symptoms, is it necessary or not?

BACKGROUND AND AIMS: Retrospectively analyze the sensitivity of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) in the diagnosis of gastric malignancy compared with gastric endoscopy in persons with nonspecific symptoms and evaluate the necessity of 18F-FDG PET-CT scan before surgery. MATERIALS AND METHODS: A total of 53 patients with gastric malignancy proven by surgery and pathology were enrolled in the study. All the patients underwent gastric endoscopy and PET-CT scan before surgery. And the PET-CT images were interpreted by the observers who were blinded to the results of the gastric endoscopy. The sensitivity of gastric endoscopy, 18F-FDG PET-CT, and serum tumor markers in the diagnosis of gastric malignancy were calculated ultimately. RESULTS: Of 53 gastric malignancy patients, five cases were proven to be false-negative detected by gastric endoscopy, and the sensitivity of which was 90.57%. The sensitivity of PET scan alone was 86.79%, which was observed no significant difference to that of gastric endoscopy diagnosis, P = 0.54. While all of the patients had been detected positive on PET-CT images, the sensitivity of which was significantly higher than that of the gastric endoscopy diagnosis or that of the serum tumor markers, P < 0.001. And the FDG uptake was positively correlated with the depth of the cancer invasion into the gastric wall (P < 0.0001) and the degree of lymph nodes infiltration (P = 0.02). It also various from different differentiation degree significantly, P = 0.04. CONCLUSIONS: 18F-fluorodeoxyglucose PET-CT could detect gastric carcinoma in persons with nonspecific symptoms which showed negative in gastric endoscopy. And it is necessary to be aware of the possibility of gastric malignancy when the result of PET-CT scan is positive.

Complete Genome Sequences of Two Escherichia coli O157:H7 Phages Effective in Limiting Contamination of Food Products.

We previously demonstrated that application of bacteriophages significantly reduced Escherichia coli O157:H7 contamination in spinach and ground beef. Here, we present the genomic sequences of two bacteriophages, vB_EcoS_FFH_1, a T5-like phage, and vB_EcoM_FFH_2, an rV5-like phage, used in those treatments.

Development of an anti-Salmonella phage cocktail with increased host range.

Salmonella shedding in many livestock species can increase significantly after transport and lairage. Preprocessing increases in shedding can amplify the amount of Salmonella that enters the processing facility and the likelihood of end-product contamination. We previously produced an anti-Salmonella phage cocktail that reduced colonization in swine when the pigs were exposed to an environment heavily contaminated with Salmonella, similar to what might be seen in a transport trailer or processing facility holding pen. The aim of this study was to increase the efficacy of the phage treatment by (1) expanding the host-range of the cocktail and (2) developing a more cost-effective microencapsulation technique. We collected samples from wastewater treatment facilities and isolated 20 distinct phages belonging to either the Siphoviridae or Myoviridae families. From this library we identified 10 phages that together lysed a mixed culture of Salmonella enterica Typhimurium, Enteriditis, and Kentucky--three serovars commonly associated with meat and poultry products. The phages were microencapsulated using two sodium-alginate-based methods that only reduced the cocktail titer by 1.0-1.5 logs (premicroencapsulation: 10.4 log(10) PFU/mL; postmicroencapsulation method one: 9.2 log(10) PFU/mL; postmicroencapsulation method two: 8.9 log(10) PFU/mL). Microencapsulated phages remained stable at both 4°C and 22°C for up to 14 days with no appreciable drop in titer (mean titer: 8.9 log(10) PFU/mL). These data indicate that phage cocktails with wider host ranges are possible and a cost-effective microencapsulation process can protect the phages over an extended period, making simultaneous treatment of large numbers of animals with feed- or water-based delivery possible.