115 research outputs found
Yield improvement of exopolysaccharides by screening of the Lactobacillus acidophilus ATCC and optimization of the fermentation and extraction conditions
Exopolysacharides (EPS) produced by Lactobacillus acidophilus play an important role in food processing with its well-recognized antioxidant activity. In this study, a L. acidophilus mutant strain with high-yielding EPS (2.92±0.05 g/L) was screened by chemical mutation (0.2 % diethyl sulfate). Plackett-Burman (PB) design and response surface methodology (RSM) were applied to optimize the EPS fermentation parameters and central composite design (CCD) was used to optimize the EPS extraction parameters. A strain with high-yielding EPS was screened. It was revealed that three parameters (Tween 80, dipotassium hydrogen phosphate and trisodium citrate) had significant influence (P < 0.05) on the EPS yield. The optimal culture conditions for EPS production were: Tween 80 0.6 mL, dipotassium hydrogen phosphate 3.6 g and trisodium citrate 4.1 g (with culture volume of 1 L). In these conditions, the maximum EPS yield was 3.96±0.08 g/L. The optimal extraction conditions analyzed by CCD were: alcohol concentration 70 %, the ratio of material to liquid (M/L ratio) 1:3.6 and the extraction time 31 h. In these conditions, the maximum EPS extraction yield was 1.48±0.23 g/L. It was confirmed by the verification experiments that the EPS yield from L. acidophilus mutant strains reached 5.12±0.73 g/L under the optimized fermentation and extraction conditions, which was 3.8 times higher than that of the control (1.05±0.06 g/L). The results indicated that the strain screening with high-yielding EPS was successful and the optimized fermentation and extraction conditions significantly enhanced EPS yield. It was efficient and industrially promising
Electromagnetic radiation at 900Â MHz induces sperm apoptosis through bcl-2, bax and caspase-3 signaling pathways in rats
Physiological Function of Fermented Modified Dietary Fiber and Its Application in Food
Soluble dietary fiber has small molecular weight, disordered structure and good physicochemical properties. However, natural dietary fiber possesses low bioavailability due to the low content of soluble dietary fiber, so it is essential to modify it. Traditional modification methods such as physical and chemical methods have the disadvantages of high cost, high energy consumption and environmental pollution. Enzymes produced by microorganisms are able to break the glycosidic bond of macromolecules and convert insoluble macromolecules into soluble dietary fiber. Therefore, fermentation is a low-cost, low energy consumption, green and pollution-free new modification method. This article systematically explains the principle of fermentation modification and the factors that affect the modification effect, such as inoculation amount, temperature, pH and so on, then it introduces the physiological function of dietary fiber by fermentation modification and its application in food products such as flour products, dairy products, meat products, providing theoretical basis for further development and utilization of dietary fiber in the future
Optimal immobilization of \u3b2-glucosidase into chitosan beads using response surface methodology
Background: \u3b2-Glucosidase is known as an effective catalyst for
the hydrolysis of various glycosides and immobilization is one of the
most efficient strategies to improve its activity recovery and
properties. Results: Crosslinking-adsorption-crosslinking method was
employed to immobilize \u3b2-glucosidase into chitosan beads and
response surface methodology (RSM) was used to optimize the immobilized
conditions of the maximum activity recovery. Enzyme concentration and
adsorption time were found to be significant influence factors, and the
maximum activity recovery (50.75%) obtained from response surface
methodology was in excellent agreement with experimental value
(50.81%). Furthermore, various characteristics of immobilized
\u3b2-glucosidase were evaluated. Compared to the free
\u3b2-glucosidase, the immobilized enzyme exhibited broader pH and
temperature ranges, enhanced thermal stability, better storage
stability and reusability and higher accessibility of the substrate to
the immobilized \u3b2-glucosidase. Conclusion: Response surface
methodology (RSM) was proved to be much economical for optimum
immobilization of \u3b2-glucosidase into chitosan beads
Comparative Assessment of the Bioremedial Potentials of Potato Resistant Starch-Based Microencapsulated and Non-encapsulated Lactobacillus plantarum to Alleviate the Effects of Chronic Lead Toxicity
Lead (Pb) is a well-recognized and potent heavy metal with non-biodegradable nature and can induce the oxidative stress, degenerative damages in tissues, and neural disorders. Certain lactic acid bacterial strains retain the potential to mitigate the lethal effects of Pb. The present work was carried out to assess the Pb bio-sorption and tolerance capabilities of Lactobacillus plantarum spp. Furthermore, potato resistant starch (PRS)-based microencapsulated and non-encapsulated L. plantarum KLDS 1.0344 was utilized for bioremediation against induced chronic Pb toxicity in mice. The experimental mice were divided into two main groups (Pb exposed and non-Pb exposed) and, each group was subsequently divided into three sub groups. The Pb exposed group was exposed to 100 mg/L Pb(NO3)2 via drinking water, and non-Pb exposed group was supplied with plain drinking water during 7 weeks prolonged in vivo study. The accumulation of Pb in blood, feces, renal, and hepatic tissues and its pathological damages were analyzed. The effect of Pb toxicity on the antioxidant enzyme capabilities in blood, serum, as well as, on levels of essential elements in tissues was also calculated. Moreover, KLDS 1.0344 displayed remarkable Pb binding capacity 72.34% and Pb tolerance (680 mg/L). Oral administration of both non- and PRS- encapsulated KLDS 1.0344 significantly provided protection against induced chronic Pb toxicity by increasing fecal Pb levels (445.65 ± 22.28 μg/g) and decreasing Pb in the blood up to 137.63 ± 2.43 μg/L, respectively. KLDS 1.0344 microencapsulated with PRS also relieved the renal and hepatic pathological damages and improved the antioxidant index by inhibiting changes in concentrations of glutathione peroxidase, glutathione, superoxide dismutase, malondialdehyde, and activated oxygen species, which were affected by the Pb exposure. Overall, our results suggested that L. plantarum KLDS 1.0344 either in free or encapsulated forms hold the potentiality to deliver a dietetic stratagem against Pb lethality
Patterns of pediatric and adolescent female genital inflammation in China: an eight-year retrospective study of 49,175 patients in China
BackgroundGenital inflammation is one of the most frequent clinical complaints among girls, which was easily overlooked by the general public. This study aimed to investigate the patterns and epidemiological characteristics of pediatric and adolescent female genital inflammation in China.MethodsA retrospective observational study (2011 to 2018) was conducted among all female patients under the age of 0–18 years at the Department of Pediatric and Adolescent Gynecology of The Children’s Hospital, Zhejiang University School of Medicine. Data were collected from the electronic medical records. The abnormal vaginal discharge of patient was collected for microbiological investigation by bacterial and fungal culture. Descriptive analysis was conducted to evaluate the genital inflammation pattern and epidemiological characteristics, including age, season, and type of infected pathogens.ResultsA total of 49,175 patients met the eligibility criteria of genital inflammation and 16,320 patients later came to the hospital for follow-up over the study period. The number of first-visit increased gradually from 3,769 in 2011 to 10,155 in 2018. The peak age of the first visit was 0–6 years old. Non-specific vulvovaginitis, lichen sclerosis, and labial adhesion were the top three genital inflammation. Among the top five potential common pathogens of vaginal infection, the prevalence of Haemophilus influenzae cases was the highest (31.42%, 203/646), followed by Streptococcus pyogenes (27.74%, 176/646), Candida albicans (14.09%, 91/646), Escherichia coli (8.51%, 55/646), and Staphylococcus aureus (6.35%, 41/636). The specific disease categories and pathogens of genital inflammation vary by age groups and season.ConclusionOur study summarizes the pattern of pediatric and adolescent female genital inflammation over an 8-year period in China, emphasizing the need for more public awareness, healthcare services and research in this field
Detection of early-universe gravitational-wave signatures and fundamental physics
Detection of a gravitational-wave signal of non-astrophysical origin would be a landmark discovery, potentially providing a significant clue to some of our most basic, big-picture scientific questions about the Universe. In this white paper, we survey the leading early-Universe mechanisms that may produce a detectable signal—including inflation, phase transitions, topological defects, as well as primordial black holes—and highlight the connections to fundamental physics. We review the complementarity with collider searches for new physics, and multimessenger probes of the large-scale structure of the Universe.Peer reviewe
Detection of early-universe gravitational-wave signatures and fundamental physics
Detection of a gravitational-wave signal of non-astrophysical origin would be a landmark discovery, potentially providing a significant clue to some of our most basic, big-picture scientific questions about the Universe. In this white paper, we survey the leading early-Universe mechanisms that may produce a detectable signal—including inflation, phase transitions, topological defects, as well as primordial black holes—and highlight the connections to fundamental physics. We review the complementarity with collider searches for new physics, and multimessenger probes of the large-scale structure of the Universe.Peer reviewe
Electromagnetic radiation at 900Â MHz induces sperm apoptosis through bcl-2, bax and caspase-3 signaling pathways in rats
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