Enterobacter asburiae E7, a Novel Potential Probiotic, Enhances Resistance to Aeromonas veronii Infection via Stimulating the Immune Response in Common Carp (Cyprinus carpio).

Probiotics are an alternative strategy for antibiotics, but most probiotics are Gram-positive bacteria suitable for terrestrial animals. Therefore, it is imperative to develop dedicated probiotics for the common carp industry to be ecologically efficient and environmentally friendly. A novel Enterobacter asburiae named E7 was isolated from the intestine of healthy common carp and displayed an extensive antibacterial spectrum against Aeromonas hydrophila, A. veronii, A. caviae, A. media, A. jandaei, A. enteropelogenes, A. schubertii, A. salmonicida, Pseudomonas aeruginosa, Ps. putida, Plesiomonas shigelloides, and Shewanella. E7 was nonpathogenic to the host and susceptible to the majority of antibiotics used in human clinical practice. E7 could grow between 10 and 45°C and between pH 4 and 7 and was extremely resistant to 4% (wt/vol) bile salts. Diets were supplemented with 1 × 107 CFU/g E. asburiae E7 for 28 days. No significant difference in the growth of fish was observed. Expression of immune-related genes IL-10, IL-8, and lysozyme in common carp kidney was significantly upregulated at weeks 1, 2, and 4 (P < 0.01). A significant upregulation of IL-1ß, IFN, and TNF-α expression was observed after week 4 (P < 0.01). There was a significant increase in mRNA expression of TGF-ß at week 3 (P < 0.01). Following challenge by Aeromonas veronii, the survival rate (91.05%) was significantly higher than observed in the controls (54%; P < 0.01). Collectively, E. asburiae E7 is a promising new Gram-negative probiotic that can enhance health and bacterial resistance of aquatic animals and could thus be developed as an exclusive aquatic probiotic. IMPORTANCE In the present study, we evaluated for the first time the efficiency of Enterobacter asburiae as a prospective probiotic for aquaculture applications. The E7 strain showed extensive resistance to Aeromonas, no pathogenicity to the host, and stronger environmental tolerance. We observed that the resistance of common carp to A. veronii was enhanced by feeding a diet containing 1 × 107 CFU/g E. asburiae E7 for 28 days, but growth was not improved. Strain E7 can act as an immunostimulant to induce the upregulation of some innate cellular and humoral immune responses, resulting in enhanced resistance to A. veronii. Hence, the continuous activation of immune cells can be maintained by adding suitable fresh probiotics to the diet. E7 has the potential to act as a probiotic agent for green, sustainable aquaculture and aquatic product safety.

Exploring the interaction between Cry1Ac protein and Zn2+, Cd2+ metal ions by fluorescence quenching and molecular docking approaches.

Bacillus Thuringiensis (Bt) protein has a strong ability to complex with metal ions, which may increase the transport of metal ions in the soil multi-media system. In this study, the interactions between Cry1Ac protein and metal ions (Zn2+ and Cd2+) were investigated through spectroscopies and molecular docking methods. The spectra results showed that both Zn2+ and Cd2+ quenched the fluorescence intensity of Cry1Ac protein through the static quenching. The binding constants with 4-5 orders of magnitude also indicated the interactions between the ions and the Cry1Ac protein. The thermodynamic analysis showed that hydrogen bonds and van der Waals forces were predominant during the processes. In terms of the Förster non-radiation energy transfer theory, the binding distances between metal ions and Cry1Ac protein were approximately 0.21-0.24 nm, indicating the existence of a non-radiative energy transfer between them. Furthermore, molecular docking revealed that the metal ions participated in ligand binding with the Cry1Ac at the locations Asp569, Thr560, Asn564 and Gln566. The present work provided reasonable models helping us further understand the transport effect of heavy metals in the presence of Cry1Ac. The results could provide mechanistic insights into the nature of metal ions-Cry1Ac interactions and offer important information on the toxicity risk of metal ions-Cry1Ac binding interactions.

Effects of potential probiotic Bacillus velezensis K2 on growth, immunity and resistance to Vibrio harveyi infection of hybrid grouper (Epinephelus lanceolatus♂ × E. fuscoguttatus♀).

Nowadays, there is no suitable treatment for vibriosis in groupers. So an eco-efficient and environmentally friendly treatment is necessary for the grouper industry. Probiotic-feeding has been a promising strategy to control the bacterial pathogens in aquaculture. A new Bacillus velezensis strain named K2 was isolated from the intestinal tract of healthy grouper, and exhibited wide antimicrobial spectrum of against fish pathogens, including Vibrio harveyi, Vibrio alginolyticus, Aeromonas hydrophila, Aeromonas veronii, Aeromonas caviae, Enterococcus casseliflavus and Lactococcus garvieae. Moreover, results of the safety of B. velezensis K2 showed that intraperitoneal injection of K2 in healthy grouper did not cause any pathological abnormality or death, indicating this bacteria could be considered as a candidate probiotic in aquaculture. Groupers were fed with the diets containing 1 × 107 cfu/g of B. velezensis K2 for 4 weeks. Various immune parameters were examined at 1, 2, 3, and 4 weeks of post-feeding. Results showed that diets supplemented with K2 significantly increased serum acid phosphatase (ACP) activity (P < 0.05). Results of the mRNA expression of immune-related genes in the head kidney of hybrid grouper showed that the expression of lysozyme gene was significantly upregulated after 1 and 2 weeks of feeding (P < 0.05). A significant up-regulation of the expression of piscidin, IgM and MyD88 were detected at day 21, whereas the TLR3 and TLR5 showed lower expression compared to the controls during 21 days, and a significant decrease of TLR3 gene was found at day 28 (P < 0.05). After challenge with V. harveyi, the survival rate of fish administrated with the strain K2 for 28 days was signifiacantly higher than the controls without this strain (P < 0.05). These results collectively suggest that B. velezensis K2 is a potential probiotic species to improve health status and disease resistance and can be developed as a probiotic agent in grouper industry.

Magnetic resonance imaging evaluation after radiofrequency ablation for malignant lung tumors.

OBJECTIVE: The objective of this study was to investigate magnetic resonance imaging (MRI) assessment of the therapeutic response in small lung malignancies (<3 cm) immediately after radiofrequency ablation (RFA). MATERIALS AND METHODS: This is a retrospective analysis of MRI performance in 24 cases of small lung tumors (16 primary, 8 metastatic; 20 patients) immediately, post-RFA, and at follow-up. Variables measured included maximum diameters of tumors on pre-RFA MRI, central areas of low signal intensity (SI) on post-RFA T2-weighted images (T2WIs), and central areas of high SI on post-RFA T1WIs. Additional post-RFA measurements included the maximum diameters for areas of ground-glass opacities (GGOs) on computed tomography (CT), high SI on T2WIs, and isointense SI on T1WIs. Mean values were used for statistical analysis. RESULTS: Before RFA, 16 primary and seven metastatic lung tumors showed isointense signals on T1WIs and hyperintense signals on T2WIs. Immediately after RFA, the ablated lesions showed central low signals and peripheral high annular signals on T2WIs and central high signals and peripheral annular isointense signals on T1WIs, with reduced SI on diffusion-weighted images. Significant differences were found between the preoperative MRI maximum tumor diameter and post-RFA diameters of central low SI areas on T2WIs and central high SI areas on T1WIs. Furthermore, there were significant differences between the post-RFA maximum diameter of circumferential high signals on T2WIs and the post-RFA maximum diameters of both GGOs on CT and circumferential isointense signals on T1WIs. There were three cases of local recurrence (two pulmonary metastases and one primary) during follow-up. CONCLUSIONS: MRI evaluation of the therapeutic response of RFA for small malignant lung tumors (<3 cm) was precise and reliable.

[Role of cytomegalovirus infection in the pathogenesis of type 2 diabetes mellitus].

OBJECTIVE: To further study the role of human cytomegalovirus (HCMV) infection in the pathogenesis of the type 2 diabetes mellitus. METHODS: HCMV DNA levels in sera from 29 type 2 diabetic patients and 23 controls were measured by quantitative polymerase chain reaction (PCR), and comparative analyses was made between HCMV DNA and T cell subsets, blood glucose (BG), insulin (Ins) and C peptide (C-P). RESULTS: The levels of HCMV DNA were (1.81+/-1.67) x 10(8) copies/ml for type 2 diabetic patients, a level significantly higher than that (5.50+/-4.30) x 10(7) copies/ml of controls. The percentage of CD8 for type 2 diabetic patients with positive HCMV DNA was 29.53%+/-2.00%, being much higher than that for controls (27.13%+/-4.12%), while the ratio of CD4/CD8 1.24+/-0.05 was significantly lower than that 1.41+/-0.10 of controls. Fasting C-P of type 2 diabetic patients with positive HCMV DNA was far lower than that of those with negative HCMV DNA, but the differences of BG and Ins between the two groups were not significant. CONCLUSION: Active HCMV infection of type 2 diabetic patients may suppress cellular immunity and its influence on the pathogenesis of the type 2 diabetes mellitus should be further studied.