Acid tolerance response of Salmonella during the squid storage and its amine production capacity analysis.

Salmonella exhibits a strong inducible acid tolerance response (ATR) under weak acid conditions, and can also induce high-risk strains that are highly toxic, acid resistant, and osmotic pressure resistant to aquatic products. However, the induction mechanism is not yet clear. Therefore, this study aims to simulate the slightly acidic, low-temperature, and high-protein environment during squid processing and storage. Through λRed gene knockout, exploring the effects of low-acid induction, long-term low-temperature storage, and two-component regulation on Salmonella ATR. In this study, we found the two-component system, PhoP/PhoQ and PmrA/PmrB in Salmonella regulates the amino acid metabolism system and improves bacterial acid tolerance by controlling arginine and lysine. Compared with the two indicators of total biogenic amine and diamine content, biogenic amine index and quality index were more suitable for evaluating the quality of aquatic products. The result showed that low-temperature treatment could inhibit Salmonella-induced ATR, which further explained the ATR mechanism from the amino acid metabolism.

Improvement of 1,3-propanediol production from crude glycerol by co-cultivation of anaerobic and facultative microbes under non-strictly anaerobic conditions.

BACKGROUND: Natural microbial consortia could efficiently produce 1,3-propanediol (1,3-PDO), a most promising bulk biochemical derived from glycerol that can be used as a monomer in the synthesis of polytrimethylene terephthalate (PTT). While natural microbial communities are made up of a diverse range of microbes with frequently unknown functions, the construction of synthetic microbial consortia allows for the creation of more defined systems with lower complexity. RESULTS: In this study, the synthetic microbial consortia were constructed by combining facultative microbes of Klebsiella pneumoniae DUT2 (KP) and/or Escherichia coli DUT3 (EC) cultures with the strictly anaerobic microbe of Clostridium butyricum DUT1 (CB) cultures under micro-aerobic conditions. The function of EC and KP during the fermentation process was to deplete oxygen and create an anaerobic environment for CB. Furthermore, KP competes with CB for the consumption of crude glycerol and the production of 1,3-PDO. The interaction of commensalism and competition resulted in the construction of synthetic microbial consortia capable of efficiently converting crude glycerol to 1,3-PDO even under micro-aerobic conditions. In a batch fermentation, the synthetic CB:KP co-culture at an initial abundance ratio of 92.5:7.5, yielded a maximum 1,3-PDO concentration of 52.08 g/L, with a yield of 0.49 g/g and a productivity of 1.80 g/(L.h), which increased by 10%, 9%, and 12%, respectively, when compared to the CB mono-culture under strictly anaerobic conditions. The final 1,3-PDO concentration, yield, and productivity by the synthetic CB:KP consortia increased by 16%, 19%, and 84%, respectively, when compared to the KP mono-culture. At an initial abundance ratio of 85:7.5:7.5, the synthetic CB:KP:EC co-culture achieved the highest 1,3-PDO flux of 49.17%, while 7.43%, 5.77%, 3.15% 4.24%, and 2.13% of flux was distributed to butyric acid, acetic acid, lactic acid, ethanol, and succinic acid pathways. In a fed-batch fermentation, the synthetic CB:KP:EC co-culture demonstrated a maximum 1,3-PDO concentration of 77.68 g/L with a yield of 0.51 g/g which is 30% and 13% higher than the production by the CB mono-culture at 0.02 vvm (nitrogen volume/culture volume/min) N2 supply. The initial abundance of CB, which is guaranteed to be at least 85%, enables efficient 1,3-PDO production from crude glycerol via the development of synthetic microbial consortia. CONCLUSION: The synthetic microbial consortia demonstrated excellent performance on 1,3-propanediol production under micro-aerobic conditions through the interaction of commensalism and competition. The experimental results demonstrated the potential benefit of using synthetic microbial consortia to produce 1,3-propanediol from crude glycerol.

Vitamin D3/vitamin D receptor signaling mitigates symptoms of post-stroke depression in mice by upregulating hippocampal BDNF expression.

Elucidation of the pathogenic mechanisms underlying post-stroke depression (PSD) could aid in the development of effective treatments. The present study explored whether Vitamin D3 (VitD3) can function as an antidepressant in PSD model mice and whether the effect is mediated by upregulation of brain-derived neurotrophic factor (BDNF). Mice were subjected to middle cerebral artery occlusion (MCAO) combined with chronic unpredicted mild stress (CUMS) to established the PSD model. For the mice in each group, Longa and Berderson behavioral tests were performed to evaluate motor function, sucrose preference and forced swimming tests were conducted to assess the cardinal depression-like behaviors anhedonia and helplessness, and western blot and immunohistochemistry were conducted to measure the levels of vitamin D receptor (VDR) and BDNF expression levels in mouse hippocampus. Compared to MCAO alone, subsequent CUMS aggravated motor dysfunction and depression-like behaviors, whereas injection of calcitriol (VitD3) enhanced expression levels of VDR and BDNF in the hippocampus as well as ameliorated both motor dysfunction and depression-like behaviors of PSD model mice, with optimal efficacy at 25 µg/kg. Injection of a BDNF-binding protein (TrkB-IgG) almost completely reversed the antidepressant and neuroprotective effects of VitD3, strongly suggesting that VitD3 improved motor dysfunction and depression-like behaviors in PSD model mice by promoting hippocampal BDNF signaling. Modulation of hippocampal BDNF by VitD3 treatment could be an effective strategy for prevention and treatment of PSD.

Low Vitamin D Status is Associated with Increased Thyrotropin-Receptor Antibody Titer in Graves Disease.

OBJECTIVE: Vitamin D deficiency is reportedly linked to a variety of autoimmune diseases. However, the relationship between thyroid autoimmunity in Graves disease (GD) and vitamin D deficiency is unclear. The goal of this study was to determine whether increased thyroid hormone autoantibody titer is associated with vitamin D deficiency in GD patients. METHODS: A total of 70 patients with GD and 70 matched control subjects were recruited to our study. The levels of 25-hydroxyvitamin D (25[OH]D), calcium, parathyroid hormone (PTH), free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyrotropin-receptor antibody (TRAb), thyroid-peroxidase antibody (TPOAb), and thyroglobulin antibody (TGAb) in serum collected from these patients and controls were examined. RESULTS: The level of 25(OH)D in serum from TRAb-positive GD patients was significantly lower than that in serum of healthy controls or TRAb-negative patients. However, compared with control subjects, the level of PTH in serum was increased in TRAb-positive GD patients. The rate of vitamin D deficiency (defined as serum 25[OH]D <50 nmol/L) in TRAb-positive GD patients was significantly higher than in healthy controls or TRAb-negative GD patients. The level of 25(OH)D in serum was inversely correlated with TRAb titer in serum of TRAb-positive GD patients. However, our results did not show a correlation between 25(OH)D level and the levels of TPOAb, TGAb, FT3, FT4, or TSH. CONCLUSION: Low vitamin D status is associated with increased TRAb titer in GD, suggesting a possible link between vitamin D status and increased thyroid autoimmunity in GD patients.

[Crosssectional survey of human papilloma virus subtype distribution and cervical intraepithelial neoplasia in Shenzhen].

OBJECTIVE: To investigate the prevalence of human papilloma virus (HPV) infection and cervical intraepithelial neoplasia (CIN) and pathogenecity of the HPV subtyping and virus loads in Shenzhen district. METHODS: In the study, 10 000 sexually active women from Shenzhen city and rural areas around were screened for cervical cancer, and all the cases were examined with cytology tests and several kinds of high risk HPV (HR-HPV) tests. Those with cytology ≥atypical squamous cells of undetermined sign (ASC-US) or positive HPV results underwent colposcopy with biopsy for a pathological diagnosis. RESULTS: The average age of this study population was 38.9 years. The total prevalence of HPV infection was 16.6%, with age-specific prevalence increasing with age. The morbidity rate of the low grade cervical intraepithelial neoplasia CIN1 was 17.0%, but that with those aged ≥55 years showed a sharp drop. The morbidity rate of the high grade cervical intraepithelial neoplasia CIN2/3 was 2.6%, and was higher in the 45 to 59 years age group than in the 25 to 44 years age group. HR-HPV infection was an obvious relevant factor of CIN1 and CIN2/3, and the OR values increased as the virus loads increased, but they had different relevant HPV subtypes. We found that HPV-16, -58, -31, -33, -18 were the first five ones for CIN2/3 while HPV-39, -58, -59, -52, -66 for CIN1. CONCLUSION: There is a high level of HPV infection and CIN in Shenzhen district. The prevalence of HPV infection has a trend to increase with age, and the people aged 45 years and more are key objects for CIN2/3 screening, with the virus load and subtyping of HR-HPV infection as indicative factors.

[Relevant factors to female human papillomavirus infection in city and rural areas of Shenzhen].

OBJECTIVE: To study the differences of relevant factors to human papillomavirus (HPV) infection between urban and rural women. METHODS: 10 000 sexually active women from Shenzhen city and rural areas were interviewed with questionnaire on risk factor to HPV infection and screened for cervical cancer, using 3 kinds of HPV test. RESULTS: Average age of the study population was 38.9, with prevalence rates of HPV infection among the total population, people in SSEZ (Shenzhen Special Economic Zone), out of SSEZ, and rural areas were 33.3%, 35.8%, 30.2%, and 33.8% respectively. Relevant factors to HPV infection in SSEZ were those mainly having had history of abortion,having more sexual partners in lifetime and husbands who work outside the area. Relevant factors to HPV infection out of SSEZ were those mainly having had more episodes of abortion, more sexual partners in lifetime and using condom more than other contraceptives. Relevant factors to HPV infection in rural area were: having more abortions and smoking behavior. CONCLUSION: There were some differences of relevant factors to HPV infection between urban and rural women. In urban area, having had more sexual partners in lifetime played a very important role in contracting HPV infection while condom use for contraception seemed to be a protective factor. In the rural areas, smoking was a risk factor for HPV infection, to some extent. Having had more episodes on abortion showed as a common risk factor to both urban and rural females, on HPV infection.