Protective effect of Ganoderma lucidum-fermented crop extracts against hydrogen peroxide- or β-amyloid-induced damage in human neuronal SH-SY5Y cells

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of stacked β-amyloid peptides in the brain and associated with the generation of oxidative stress. So far, there is no cure for AD or a way to stop its progression. Although the neuroprotective effects of Ganoderma lucidum aqueous extract and G. lucidum-derived triterpenoids and polysaccharides have been reported, the influence of G. lucidum-fermented crops on AD still lacks clarity.

METHODS

This study aimed to investigate the protective effect of G. lucidum-fermented crop extracts against hydrogen peroxide- or β-amyloid peptide (Aβ25-35)-induced damage in human neuroblastoma SH-SY5Y cells.

RESULTS

Various extracts of G. lucidum-fermented crops, including extract A: 10% ethanol extraction using microwave, extract B: 70˚C water extraction, and extract C: 100˚C water extraction followed by ethanol precipitation, were prepared and analyzed. Extract B had the highest triterpenoid content. Extract C had the highest total glucan content, while extract A had the highest gamma-aminobutyric acid (GABA) content. The median inhibitory concentration (IC50, mg/g) for DPPH and ABTS scavenging activity of the fermented crop extracts was significantly lower than that of the unfermented extract. Pretreatment with these extracts significantly increased the cell viability of SH-SY5Y cells damaged by H2O2 or Aβ25-35, possibly by reducing cellular reactive oxygen species (ROS) and malondialdehyde (MDA) levels and increasing superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities. Moreover, extract B markedly alleviated the activity of acetylcholinesterase (AChE), which is crucial in the pathogenesis of AD.

CONCLUSION

These results clearly confirmed the effects of G. lucidum-fermented crop extracts on preventing against H2O2- or Aβ25-35-induced neuronal cell death and inhibiting AChE activity, revealing their potential in management of AD.

Influence of Cordyceps militaris-fermented grain substrate extracts on alleviating food allergy in mice

Background

Cordyceps militaris is recognized as a tonic in traditional Chinese medicine, and there have been documented findings on the anti-allergic properties of its extract derived from the fruiting body. Due to the limited availability of wild C. militaris, a specialized grain substrate has been devised for the solid-state fermentation of its fruiting bodies. However, the fermented grain substrate is considered waste and usually used as feeds for animals. To achieve the sustainable development goals, C. militaris-fermented grain substrate (CFGS) was collected to prepare CFGS extracts. Further, the anti-allergic properties of these extracts were assessed with the aim of exploring novel applications.

Methods

The water extract and ethanol extract of CFGS were prepared, and their potential in alleviating allergic enteritis was assessed in mice with food allergy. Assessment of immunomodulatory effects included the measurement of serum antibodies and splenic cytokines. Additionally, influence of extracts on gut microbiota composition was examined through sequencing analysis of 16S rRNA gene from freshly collected feces of the mice.

Results

Daily administration of the water and ethanol extracts, at doses of 50 or 250 mg/kg body weight, demonstrated a notable alleviation of allergic diarrhea and enteritis. This was accompanied by a decrease in mast cell infiltration in the duodenum and a reduction in allergen-specific IgE production in the serum. Both extracts led to a significant decrease in IL-4 secretion. Conversely, there was an increase in IFN-γ, IL-10, and TGF-β secretion from splenocytes. Remarkably, allergic mice exhibited a distinct fecal microbiota profile compared to that of normal mice. Intriguingly, the administration of these extracts had varying effects on the fecal microbiota.

Conclusion

Taken together, these findings collectively indicate the potential of CFGS extracts as promising candidates for functional foods. These extracts show promise in managing allergic enteritis and modulating gut microbiota.

Quantitative microbiological risk assessments for Salmonella spp. contaminated taiwanese salty chicken in the taiwanese population

The aim of the study is to develop Salmonella spp. Quantitative microbial risk assessments (QMRA) and to evaluate the risk of Salmonellosis illness in the Taiwanese population after consumption of Taiwanese salty chicken (TSC). We assume that Salmonella spp. May contaminate the fresh raw chicken used in TSC. After transport to the diner, fresh raw chicken is received, cleaned, and surface-washed by diner staff. The TSC is then cooked and sold to consumers. We set four different cross-contamination scenarios to evaluate the contamination level of Salmonella spp. In TSC. We used a Monte Carlo simulation method, a probabilistic analysis method, and exceedance risk to evaluate the risk of Salmonellosis illness. When the exceedance risk was 5 %, and taking the Taiwanese population above 19 years old as an example, the rate of contracting Salmonellosis from the consumption of TSC will be 2.94 % (2.94 million per 100 million people) if the chef does not clean their hands, knives, or cutting boards. However, if the chef washes their hands, knives, and cutting boards with cold water and soap, the illness rate of Salmonellosis from consuming TSC will be 1.93E-04 % (193 per 100 million people). Sensitivity analysis indicates that the most important risk factor in the QMRAs of TSC is the temperature of the fresh raw chicken during transportation, following which were the Salmonella spp. Residual. If the staff of the diner separates the cooking tools used for raw ingredients and those for cooked food, the illness risk of Salmonellosis will be very low.

Effects of Fermented Citrus Peel on Ameliorating Obesity in Rats Fed with High-Fat Diet

Although citrus peel is a waste material, it contains a variety of bioactive components. As our preliminary findings showed that citrus peels fermented with Saccharomyces cerevisiae T1 contained increased levels of anti-obesity flavonoids, the objective of this study was to prepare fermented citrus peel and to investigate its effect on ameliorating obesity in Sprague Dawley (SD) rats fed with a high-fat diet (HFD). After fermentation, the amounts of limonene, nobiletin and 3-methoxynobiletin in citrus peel were markedly increased. SD rats were fed with an HFD for 10 weeks, followed by fermented citrus peel-containing HFD (0.3% or 0.9% w/w) for 6 weeks. Compared with those fed with an HFD alone, lower levels of body weight, visceral fat, body fat percentage, blood triglyceride, total cholesterol, low-density lipoprotein, malondialdehyde and hepatic adipose accumulation were observed in rats fed with fermented citrus peel. In parallel, hepatic levels of acetyl-CoA carboxylase and fatty acid synthase were diminished, and the level of hormone sensitivity lipase in visceral fat was elevated. These results reveal fermented citrus peel is a promising natural product with beneficial effects of alleviating HFD-induced obesity.

Development of Fermented Shrimp Shell Product with Hypoglycemic and Hypolipidemic Effects on Diabetic Rats

In 2020, approximately 9.3 billion tons of crustaceans were consumed, and 45–48% of shrimp shell (SS) by-products were discarded as waste. In this study, the SS of Litopenaeus vannamei was fermented by Lactobacillus plantarum LV33204, Stenotrophomonas maltophilia LV2122 (strong proteolytic activity), and Aeromonas dhakensis LV1111 (chitin-degrading activity), and the optimal fermentation conditions of liquid-fermented SS was established. Contents of total peptide, astaxanthin, and total phenolic content of the fermented SS were significantly higher than that of unfermented SS. In the presence of fermented SS, glucose uptake and insulin resistance of TNF-α-stimulated FL83B hepatocytes were markedly improved. Furthermore, daily oral supplement of fermented SS to streptozotocin (STZ)/nicotinamide (NA)-induced diabetic rats for 7 weeks significantly reduced plasma glucose and insulin resistance. Meanwhile, ingestion of fermented SS might enhance hepatic catabolism of glucose by increasing hexokinase and glucose-6-phosphate dehydrogenase activity and decreasing glucose-6-phosphatase activity. In addition, the fermented SS downregulated plasma total cholesterol (TG), triglycerides (TCs), low-density lipoprotein cholesterol (LDL-C), liver TG, and TC and lipid peroxidation levels in diabetic rats. In conclusion, a biorefinery process for waste SS was established through mixed strain fermentation. The in vitro and in vivo data reveal that the fermented SS is a promising functional food for the management of diabetic hyperglycemia and hyperlipidemia.

Dual bacterial strains TTI for monitoring fish quality in food cold chain

Most microbial time-temperature indicators (TTIs) considered only one spoilage strain. This research compared single and dual spoilage strains-based microbial TTI for quality changes of chilled grouper fish (Epinephelus fuscoguttatus x E. lanceolatus) fillet products during distribution. The next-generation sequencing (NGS) and traditional plate count approach showed that Pseudomonas fragi and Vibrio parahaemolyticus were specific spoilage bacteria at 7 and 15°C. A dual-strain TTI response provides more accurate results than a single-strain TTI and provides an irreversible color change from yellow to reddish-brown, showing levels of fish freshness. The microbial TTI comprises fish spoilage bacteria strains with 3 log CFU/ml, a nutrient broth supplemented with 2% NaCl as a medium, and phenol red with 0.25 mg/ml as a pH indicator. Overall, this study points to the applicability of a dual-strain microbial TTI as a valuable tool for monitoring fish quality changes during cold chain break condition.

Hypouricemic Effect of Submerged Culture of Ganoderma lucidum in Potassium Oxonate-Induced Hyperuricemic Rats

Hyperuricemia is a disease caused by a high level of uric acid in the blood. It is an important factor for gout and may be linked to renal and hepatic failure. The objective of this study was to investigate the hypouricemic effects of submerged culture of Ganoderma lucidum. The lyophilized powder of mycelium (GM) and extracellular polysaccharides (GP) of the G. lucidum submerged culture were prepared. The contents of hypouricemic components, including phenolics and flavonoids, in GM (34.33 ± 0.41 mg/g and 0.32 ± 0.01 mg/g) were higher than that in GP (20.52 ± 1.49 mg/g and not detected). The hypouricemic effect of GM and GP was evaluated in potassium oxonate (PO)-injected rats. The average food intake (23.3 ± 1.2 g/day) and body weight (355.7 ± 28.0 g) were decreased, and the serum level of uric acid (5.56 ± 0.41 mg/dL) was increased in PO-injected rats. However, allopurinol (10 mg/kg b.w.) or GM treatment (200 or 400 mg/kg b.w) improved food intake (26.3 ± 2.7 g/day) and reduced the level of uric acid (4.45 ± 0.46 mg/dL). In parallel, the activity of hepatic xanthine oxidase (XOD) was downregulated from 841.29 ± 299.58 μU/mg protein to 540.80 ± 199.20 μU/mg protein. Moreover, GM and GP (200 or 400 mg/kg b.w) alleviated the level of blood urea nitrogen (BUN) from 30.49 ± 4.71 to 21.16 ± 4.25 mg/dL. GP treatment also diminished the level of alanine transaminase (ALT) from 52.63 ± 18.82 to 27.35 ±6.82 U/L. These results clearly demonstrated the hypouricemic effect of submerged G. lucidum culture and their potential against hyperuricemia-associated renal and hepatic damage. GM was more potent to alleviate hyperuricemia, and GP was more potent to improve renal and hepatic function.

Evaluation of Hypoglycemic and Antioxidant Activities of Soybean Meal Products Fermented by Lactobacillus plantarum FPS 2520 and Bacillus subtilis N1 in Rats Fed with High-Fat Diet

The hypoglycemic and antioxidant activities of Lactobacillus plantarum FPS 2520 and/or Bacillus subtilis N1 fermented soybean meal (SBM) in rats fed a high-fat diet (HFD) were investigated by assessing plasma glucose levels, insulin resistance, and oxidative stress-induced organ damage. Supplementation with FPS 2520- and/or N1-fermented SBM (500 and 1000 mg/kg of body weight per day) to HFD-induced obese rats for 6 weeks significantly down-regulated the concentration of plasma glucose during the oral glucose tolerance test (OGTT), as well as the concentration of fasting plasma glucose, insulin, and the value of the homeostasis model assessment of insulin resistance (HOMA-IR). In addition, plasma and hepatic levels of malondialdehyde (MDA) were alleviated in rats fed fermented SBM, especially SBM fermented by mixed strains. Moreover, fermented SBM treatment reduced HFD-exacerbated increases in plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and uric acid levels. Based on these results, we clearly demonstrate the effect of fermented SBM on improving insulin resistance and oxidation-induced organ damage. Therefore, it is suggested that fermented SBM has the potential to be developed as functional foods for the management of obesity-induced hyperglycemia and organ damage.

Chitosan Inhibits Helicobacter pylori Growth and Urease Production and Prevents Its Infection of Human Gastric Carcinoma Cells

This study investigated the effects of shrimp chitosan with 95% degree of deacetylation (DD95) in combination with clinical antibiotics on the growth and urease production of Helicobacter pylori. The inhibitory effect of DD95 on the adherence of H. pylori to the human intestinal carcinoma cells (TSGH9201) was also investigated. Five strains of H. pylori, including three standard strains and two strains of clinical isolates were used as the test strains. The inhibitory effects of DD95 on growth and urease production of various strains of H. pylori increased with increasing DD95 concentration and decreasing pH values from pH 6.0 to pH 2.0. Urease activity of H. pylori at pH 2.0 in the presence of 4000 μg/mL of DD95 decreased by 37.86% to 46.53%. In the presence of 50 μg/mL antibiotics of amoxicillin, tetracycline, or metronidazole at pH 6.0 and pH 2.0, H. pylori counts were decreased by 1.51–3.19, and 1.47–2.82 Log CFU/mL, respectively. Following the addition of 4000 μg/mL DD95 into the 50 μg/mL antibiotic-containing culture medium with pH 6.0 and pH 2.0, overall H. pylori counts were strongly decreased by 3.67–7.61 and 6.61–6.70 Log CFU/mL, respectively. Further, DD95 could inhibit the adherence of H. pylori on TSGH 9201 cells, as evidenced by fluorescent microscopy and thus may potentially protect against H. pylori infection.

Evaluation of Antiobesity Activity of Soybean Meal Products Fermented by Lactobacillus plantarum FPS 2520 and Bacillus subtilis N1 in Rats Fed with High-Fat Diet

Single strain or mixed strains of Lactobacillus plantarum FPS 2520 and Bacillus subtilis N1 were used to ferment soybean meal (SBM), and the antiobesity activity of the fermented SBM product was investigated in rats fed with high-fat diet (HFD). After fermentation, free amino nitrogen, total peptide, and isoflavone contents were markedly raised, and genistein and daidzein were the major isoflavones in the fermented SBM. After fed with HFD for 10 weeks, obese Sprague-Dawley rats were orally treated with various fermented products for 6 weeks. The body weight gains, as well as weights of abdominal fat and epididymis fat, of rats fed with fermented SBM products were significantly downregulated. The treatment with the mixed-strains fermented SBM product significantly decreased plasma levels of triglyceride (TG), total cholesterol (TC), and low-density lipoprotein-cholesterol, but increased the level of high-density lipoprotein-cholesterol. Moreover, the levels of TG, TC, fatty acid synthase, and acetyl-CoA carboxylase (ACC) in liver were diminished, and the activities of hormone-sensitive lipase and lipoprotein lipase in adipose tissue were augmented. Taken together, these data demonstrated the antiobesity activity of fermented SBM products, among which the product fermented by the mixed strains being the most effective one. Therefore, these fermented SBM products are potential to be developed as functional foods or additives for treatment of obesity and prevention against obesity-induced complications.

Ganoderma lucidum culture supplement ameliorates dyslipidemia and reduces visceral fat accumulation in type 2 diabetic rats

Diabetic rats were daily fed with a high-cholesterol diet containing 1% or 3% freeze-dried whole submerged G. lucidum culture or its mycelia for 5 weeks. Body weight, adipose tissue weight and plasma triglyceride levels were reduced, while high-density lipoprotein-cholesterol levels were elevated in rats fed with G. lucidum powder supplement diets. Notably, G. lucidum supplements downregulated the activities of hepatic acetyl-CoA carboxylase, fatty acid synthase and lipoprotein lipase, but upregulated the activity of hormone-sensitive lipase in the perirenal adipose tissues. Moreover, G. lucidum supplements increased the faecal triglyceride excretion. Therefore, daily supplementation of submerged G. lucidum culture, especially mycelia, can ameliorate dyslipidemia and reduce visceral fat accumulation in diabetic rats fed with a high-fat diet, which is closely related to the modulation of lipid synthesis, metabolism, and excretion.

Evaluation of the hypoglycaemic and antioxidant effects of submerged Ganoderma lucidum cultures in type 2 diabetic rats

We aim to investigate the hypoglycaemic and antioxidant effects of submerged Ganoderma lucidum cultures and elucidate the potential mechanisms behind these effects using a type 2 diabetic rat model. Diabetic rats were daily fed with a high-fat diet supplemented with 1% or 3% freeze-dried whole submerged cultures of G. lucidum or mycelia for 5 weeks. We observed significantly decreased fasting plasma glucose levels, homoeostasis model assessment equation-insulin resistance, and plasma glucose in oral glucose tolerance test. Furthermore, we observed increased levels of glycogen, hepatic hexokinase, glucose-6-phosphate dehydrogenase, and intestinal disaccharidase activities. G. lucidum supplement downregulated the plasma levels of aspartate aminotransferase, alanine aminotransferase, creatinine, and urea nitrogen as well as liver and kidney levels of thiobarbituric acid reactive substances. Based on the hypoglycaemic and antioxidant effects of G. lucidum submerged cultures, we recommend the potential application of these products as functional foods or additives for controlling type 2 diabetes. Abbreviations ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; BUN: Blood urea nitrogen; BW: Body weight; CREA: Creatinine; FPG: Fasting plasma glucose; G6Pase: Glucose-6-phosphatase; G6PD: Glucose-6-phosphate dehydrogenase; HOMA-IR: Homoeostasis model assessment of insulin resistance; OGTT: Oral glucose tolerance test; PTP: Protein tyrosine phosphatase; STZ: Streptozotocin; TBARS: Thiobarbituric acid reactive substances.

Production of Bacillus subtilis-fermented red alga Porphyra dentata suspension with fibrinolytic and immune-enhancing activities

The fermented marine alga Porphyra dentata suspension was tested for its fibrinolytic and immune-enhancing activities. An isolated Bacillus subtilis N2 strain was selected for its fibrinolytic activity on fibrin plates. After investigating the effects of biomass amounts of P. dentata powder in water, various additives including sugars, nitrogen-containing substances, lipids and minerals, and cultural conditions of temperature and agitation in flask, the highest fibrinolytic activity in the cultural filtrate was obtained by cultivating N2 strain in 3% (w/v) P. dentata powder suspension containing 1% peanut oil at 37 °C, 150 rpm for 48 h. A fermentor system was further established using the same medium with controlled pH value of 7.0 at 37 °C, 150 rpm, 2.0 vvm for 48 h for the best fibrinolytic activity. The fermented product also showed its immune-enhancing activity by increasing cell proliferation and stimulating the secretion of IL-1β, IL-6, and TNF-α in J774.1 cells.

Effects of cultural medium and conditions on the proliferation and hypoglycemic activity of Saccharomyces pastorianus no. 54

A yeast strain of Saccharomyces pastorianus no. 54 with hypoglycemic activity was isolated from soils of a winery. The aims of this study were first to investigate the effects of the cultivation conditions on proliferation and hypoglycemic activity of this yeast using the assay model of the differentiated 3T3-L1 adipocytes, and then, to confirm in vivo the hypoglycemic activity of cultured yeast by oral administration in streptozotocin (STZ)-induced diabetic mice. Among 7 diluted fruit juice samples the diluted strawberry juice (1.74 g/L reducing sugar content) was chosen as the basal medium. After investigation of the effects of addition of various substances, including 1% of 5 different sugars and glycerol, 0.1% of 6 nitrogen-containing substances, and 1 ppm of 7 growth factors, the diluted strawberry juice added with 1% glucose, 0.1% yeast extract and 1 ppm aspartic acid was optimized at 20 °C with initial pH value of 6.0 for cultivating S. pastorianus no. 54 in flask. The scale-up system of a 5-L fermentor was further established by using the same medium with initial pH 6.0 and being incubated at 20 °C with an aeration rate of 1.2 vvm for 96 h. The hypoglycemic activity of yeast cells cultivated in fermentor was 3.11 times of that in flask. Oral administration of the cultured yeast at a dosage of 130 mg/kg body weight/day for 6 days could significantly reduce the plasma glucose content in STZ-induced diabetic mice and keep their body weights in the normal range.

Monitoring and modeling density-dependent growth of anchorage-dependent cells

The density-dependent growth of Chinese hamster ovary (CHO) cells was monitored on-line by using an inverted microscope. A flow system was employed for cell cultivation so that nutrient concentration could be maintained and metabolic wastes were removed. With the help of video image analysis, local cells density could be accurately calculated and cell motility and exposed cell surface area could be estimated. A computer program which accounted for change of sell size and translocation of cells was developed to stimulate cell growth. The stimulated results of the population dynamics and the variations in cell size showed good agreement with our experimental observations, Cell motility and initial cell distribution on the substratum were found to have strong effect on cell growth.

Novel technology for the preparation of self-assembled catechin/gelatin nanoparticles and their characterization

In this study, self-assembled tea catechin/gelatin nanoparticles were prepared by directly mixing the catechins and gelatin solutions. The mean particle sizes were almost less than 200 nm, and the zeta potential values were negatively charged. FT-IR spectral analysis indicated that hydrogen bonding between aliphatic and aromatic hydroxyl groups, respectively, on gelatin and catechins is responsible for the self-assembly of nanoparticles. Free radical (DPPH* and ABTS*(+)) scavenging assays showed that tea catechins could be protected by the nanoparticles and that the antioxidant activity of tea catechins was almost retained after three weeks of storage. The tea catechin/gelatin nanoparticles exhibited 28-41% inhibition to trypsin against the degradation of gelatin. This result suggested that the tea catechin/gelatin nanoparticles might be a useful antioxidant carrier because catechins and gelatin were, respectively, protected from oxidation and enzymatic digestion.

Anti-inflammatory properties of phenolic compounds and crude extract from Porphyra dentata

ETHNOPHARMACOLOGICAL RELEVANCE

Porphyra dentata, a red edible seaweed, has long been used worldwide in folk medicine for the treatment of inflammatory diseases such as hypersensitivity, lymphadenitis, bronchitis.

AIMS OF STUDY

To clarify the anti-inflammatory role of Porphyra dentata crude extract and its identified phenolic compounds by investigating their effect on the nitric oxide (NO)/inducible nitric oxide synthase (iNOS) transcription pathway in macrophage RAW 264.7 cells.

MATERIALS AND METHODS

Porphyra dentata crude extract was prepared with methanol. High performance liquid chromatography (HPLC) hyphenated to electrospray ionization mass spectrometry (ESI-MS) and UV detection were utilized to analyze the extract fingerprints. Nitrite measurement, iNOS promoter activity and nuclear factor-kappaB (NF-kappaB) enhancer activity were used to assess the anti-inflammatory effect in lipopolysaccharide (LPS) challenged mouse RAW 264.7 cell line.

RESULTS

Phenolic compounds (catechol, rutin and hesperidin) were identified in the crude extract of Porphyra dentata. The crude extract and the phenolic compounds inhibited the production of NO in LPS-stimulated RAW 264.7 cells. Catechol was a more potent suppressor of the up-regulation of iNOS promoter and NF-kappaB enhancer than rutin and yet, hesperidin alone failed to inhibit either activity.

CONCLUSION

Our results indicate that catechol and rutin, but not hesperidin, are primary bioactive phenolic compounds in the crude extract to suppress NO production in LPS-stimulated macrophages via NF-kappaB-dependent iNOS gene transcription. The data also explain the anti-inflammatory use and possible mechanism of Porphyra dentata in iNOS implicated diseases.

Effects of chitosan and a low-molecular-weight chitosan on Bacillus cereus and application in the preservation of cooked rice

Shrimp chitosan with 95% deacetylation and low-molecular-weight chitosan (LMWC) isolated from chitosan hydrolysate were investigated for their effects on the growth of Bacillus cereus and for use in the preservation of cooked rice. Four strains of Bacillus cereus were used: standard strain BCRC 10603 and three isolates (nos. 1 through 3) from cooked rice. The antibacterial activity of chitosan against B. cereus was greatly decreased when the reaction pH was changed from 6.0 to 7.0, but LMWC activity was less affected by this pH change. The susceptibility of B. cereus cells to chitosan decreased with increasing of cell age, in accordance with the relative electronegativity of the cell surface. B. cereus spores were more sensitive to LMWC and chitosan than were vegetative cells. Addition of 80 ppm LMWC and chitosan in sterile saline (pH 7.0) greatly reduced the D-value for the tested four strains at 90 degrees C from 30.77 to 46.51 min to 7.47 to 10.17 min and 4.68 to 7.91 min, respectively, and at 100 degrees C from 1.95 to 2.56 min to 0.89 to 0.93 min and 0.72 to 0.80 min, respectively. Addition of 2,000 ppm LMWC to raw rice water before steam cooking effectively inhibited increases in total aerobic bacteria and B. cereus in cooked rice stored at 37 and 18 degrees C.

Interactive effects of microbial transglutaminase and recombinant cystatin on the mackerel and hairtail muscle protein

Interactive effects of microbial transglutaminase (MTGase) and recombinant cystatin on the mackerel and hairtail water soluble protein (WSP), salt soluble protein (SSP), and muscle protein (MP) were investigated. According to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and enzymic activity analyses, cross-linking of mackerel and hairtail myosin heavy chain and low molecular mass compounds and formation of epsilon-(gamma-glutamyl)lysine cross-links were observed on samples with MTGase, while the recombinant cystatin could effectively inhibit the cathepsins and subsequently prevent degradation of proteins during setting. The cathepsins and MTGase activities in WSP, SSP, and MP solutions decreased, but the recombinant cystatin activity increased during setting at 45 degrees C.

Antimicrobial activity of a low-molecular-weight chitosan obtained from cellulase digestion of chitosan

A water-soluble chitosan hydrolysate with high activity against Escherichia coli was obtained during cellulase digestion of chitosan for 18 h. This 18-h hydrolysate is composed of low-molecular-weight chitosan (LMWC), with a molecular weight of 12.0 kDa, and chitooligosaccharides, which are composed of sugars with a degree of polymerization of 1 to 8. LMWC has a strong activity at 100 ppm against many pathogens and yeast species, including Bacillus cereus, E. coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica serovar Typhi, and Saccharomyces cerevisiae, while the chitooligosaccharides have much weaker antimicrobial activity than does LMWC. Accordingly, the antimicrobial activity against E. coli in the 18-h hydrolysate proved to come mainly from the presence of LMWC.

Thymic hyperplasia in a patient with Graves' disease

Hyperplastic changes of the thymus may be found in patients with Graves' disease. However, this rarely presents as an anterior mediastinal mass, particularly among adults. In this report, we describe a 32-year old woman with Graves' disease and hyperthyroidism. During medical evaluation and treatment for her hyperthyroidism, a large anterior mediastinal mass was incidentally discovered. A cytological study of the lesion via computed tomogram-guided fine needle biopsy could not make a definitive diagnosis and suggested the possibility of a thymoma, which led to a surgical exploration. However, the final pathological diagnosis of the surgically removed tissue was thymic hyperplasia. The relationship between Graves' disease and thymic changes is discussed.

Antibacterial activity of a chitooligosaccharide mixture prepared by cellulase digestion of shrimp chitosan and its application to milk preservation

The antibacterial activity of a chitooligosaccharide mixture prepared by digestion of shrimp chitosan with cellulase at 50 degrees C for 14 h was evaluated. Sugars with 1 to 8 degrees of polymer (DP) were found in this chitooligosaccharide mixture, and the weight percentage of sugars with DP > or = 6 was 44.3%. Minimal lethal concentrations of this mixture against Aeromonas hydrophila, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium, Shigella dysenteriae, Staphylococcus aureus, Vibrio cholerae, and Vibrio parahaemolyticus in nutrient broth were 5 to 29 ppm, which were much lower than those of the chitosan reactant (50 to 1,000 ppm). The antibacterial activity of this mixture in the sterilized milk against E. coli O157, L. monocytogenes, Salmonella Typhimurium, and S. aureus was much stronger at 4 degrees C than at 37 degrees C. When raw milk was supplemented with either 0.24% or 0.48% (wt/vol) of this oligosaccharide mixture and stored at 4 degrees C for 12 days, its mesophilic and psychrotrophic counts were reduced by at least 3 log cycles, and there was very little change in pH. In addition, this mixture retarded the growth of Salmonella species and caused quicker reduction of Staphylococcus species in raw milk. Accordingly, the shelf life of raw milk at 4 degrees C was extended by at least 4 days.

Antibacterial activity of shrimp chitosan against Escherichia coli

The effects of cell age, reaction temperature, pH value, and salts on the inhibitory activity of shrimp chitosan (98% deacetylated) against Escherichia coli were investigated. The age of a bacterial culture affected its susceptibility to chitosan, with cells in the late exponential phase being most sensitive to chitosan. Higher temperature (25 and 37 degrees C) and acidic pH increased the bactericidal effects of chitosan. Sodium ions (100 mM Na+) might complex with chitosan and accordingly reduce chitosan's activity against E. coli. Divalent cations at concentrations of 10 and 25 mM reduced the antibacterial activity of chitosan, in the order of Ba2+ > Ca2+ > Mg2+. Chitosan also caused leakage of glucose and lactate dehydrogenase from E. coli cells. These data support the hypothesis that the mechanism of chitosan antibacterial action involves a cross-linkage between the polycations of chitosan and the anions on the bacterial surface that changes the membrane permeability.

Antibacterial effects of N-sulfonated and N-sulfobenzoyl chitosan and application to oyster preservation

The antibacterial effects of sulfonated and sulfobenzoyl chitosans were evaluated and compared with that of 69% deacetylated chitosan (DD69 chitosan). Minimal inhibitory concentrations of sulfonated chitosan (SC1, 0.63% sulfur content) against Shigella dysenteriae, Aeromonas hydrophila, Salmonella typhimurium, and Bacillus cereus were found to be lower than those of DD69 chitosan. A high sulfur content in sulfonated chitosan adversely influenced its antibacterial effect. Sulfobenzoyl chitosan (SBC) has excellent water solubility and an antibacterial effect comparable to that of SC1. SBC at 1,000 and 2,000 ppm extended the shelf life of oysters at 5 degrees C by 4 days at the former or by 7 days at least at the latter concentration. The growth of coliforms and Pseudomonas, Aeromonas, and Vibrio species on oysters was retarded by the addition of DD69 chitosan or SBC.

Effects of temperature, medium composition, pH, salt and dissolved oxygen on haemolysin and cytotoxin production by Aeromonas hydrophila isolated from oyster

The effects of temperature, medium composition, pH, salt content and dissolved oxygen (DO) on the production of haemolysin and cytotoxin by one strain of Aeromonas hydrophila isolated from oyster were investigated. Four media were tested: brain heart infusion broth (BHIB), casamino acid-yeast extract broth (CAYEB), nutrient broth (NB), and trypticase soy broth (TSB). BHIB was the best for toxin production even though the growth rates for Aeromonas hydrophila in all of these media were quite similar. Aeromonas hydrophila could produce haemolysin and cytotoxin at 37, 28 and 5 degrees C; however, the toxins were produced faster and were more stable at 28 degrees C than at 37 degrees C. Although Aeromonas hydrophila itself is tolerant to 5% (w/v) salt in BHIB and a pH range of pH 5.5 to 10.0, the production of haemolysin and cytotoxin was apparently decreased in the presence of 1-5% (w/v) NaCl or when the pH of the medium was greater or less than 7.2. The DO values in the culture medium during the stationary growth phase also seemed to affect toxin production; greater quantities of toxins were produced when the DO values were higher.

An Enzyme-Linked Immunosorbent Assay for the Detection of Aspergillus parasiticus and Aspergillus flavus

An enzyme-linked immunosorbent assay (ELISA) was established for the specific detection of Aspergillus parasiticus and Aspergillus flavus . A New Zealand white rabbit was immunized intravenously with 100 μg of A. parasiticus CCRC 30117 mycelial protein extracts. The antibodies were separated and purified. The optimal concentration of the antibody and antibody-peroxidase conjugate used in the established ELISA was 10 μg/ml with a detection limit of 1 μg/ml. Among the 126 strains tested (including 21 strains of A. parasiticus , 11 strains of A. flavus , 34 isolates of A. parasiticus / A. flavus from cereals, and 60 strains of non- A. parasiticus / A. flavus fungi), the false-negative and false-positive rates were 1.5 and 3.3%, respectively. Strains of Aspergillus flavofrucatis and Aspergillus sojae produced false-positive reactions. However, their antigens had much lower cross-reactivity with the antibodies raised against A. parasiticus , as shown from I₅₀ values. The molecular weights of the main antigens of A. parasiticus were 94, 82, and 40 kDa. The two heavier antigens had higher sugar contents, as demonstrated by SDS-PAGE and immunoblotting. A good correlation (r = 0.97) was found between mycelium measurement by weighing and by ELISA for A. parasiticus grown in yeast extract sucrose broth (YESB) at 25°C.

Microbiological evaluation of bottled uncarbonated mineral water in Taiwan

The microbiological quality of 136 samples of bottled uncarbonated mineral water, including 88 domestic and 48 imported samples, was investigated. The numbers of samples with heterotrophic plate count (HPC) over the maximum level legally permitted in Taiwan (200 colony forming units ml-1) were 45 (51.1%) and 29 (60.4%) for domestic and imported samples, respectively. Coliforms and faecal streptococci were not detectable in the samples tested. Two of the domestic samples were contaminated with Aeromonas hydrophila and four with Pseudomonas aeruginosa. Bacteria isolated from water samples were identified as species of Pseudomonas, Aeromonas, Flavobacterium, Pasteurella, Xanthomonas, and Staphylococcus. Mold and yeast were detected in 38.6% and 18.8% of domestic and imported samples, respectively. The HPC of bottled mineral water stored at 25 degrees C increased quickly to 10(4)-10(5) colony forming units ml-1. In inoculation studies both A. hydrophila and Escherichia coli grew very well and mutualistic growth for both organisms was observed in mineral water at 25 degrees C.

Incidence and toxigenicity of Aeromonas hydrophila in seafood

Three selective media, Oxoid Aeromonas agar (OA), blood ampicillin agar (BA) and starch ampicillin agar (SA) were used to evaluate the presence of Aeromonas hydrophila in 66 samples of oyster, shrimp, fish and surimi products. Oyster had the highest incidence, with 50% positive, whilst no A. hydrophila was found in the surimi. Of the three selective media, BA displayed the highest recovery rate of A. hydrophila from seafood. Forty-eight isolates from this survey were tested for their capability to produce hemolysin and cytotoxin. Hemolysin was produced by 79.2% of the isolates and cytotoxin was produced by 91.7% of the isolates in brain heart infusion broth. One of the toxin-producing isolates from oyster, strain 8-169, was further tested for growth and toxin production in oyster, shrimp and fish at various temperatures. This particular isolate grew best and had highest toxin production in oyster. Hemolysin and cytotoxin were produced earlier at 28 degrees C than at 37 degrees C, and titers of hemolysin were also higher at 28 degrees C. At 5 degrees C, it was able to grow and produce hemolysin in oyster.

Partial purification and characterization of mold antigens commonly found in foods

Rapid methods are needed for detection of molds in foods; therefore, an enzyme-linked immunosorbent assay was developed. The extracellular and mycelial antigens for Mucor, Aspergillus, Cladosporium, and Geotrichum species were partially purified and characterized. The molecular masses of the mycelial and extracellular antigens, as determined by size exclusion chromatography, ranged from 4.5 x 10(5) to 6.7 x 10(5) Da. There was only one main antigenic peak separated by Sepharose CL-4B and concanavalin A-Sepharose columns for Mucor, Cladosporium, and Geotrichum mycelial and extracellular antigens, but there were two for Aspergillus mycelial antigens and three for Aspergillus extracellular antigens. These antigens contained 10 to 50% protein which was part of the active site since protease digestion significantly decreased antigenic activity. Neutral sugars, ranging from 13 to 75%, made up the rest of the active site, and < 1% phosphate was detected in mycelial antigens. Geotrichum, Cladosporium, and Aspergillus antigens contained mainly glucose, galactose, and mannose. Mucor antigens contained these sugars plus fucose. The percentage of sugars differed between the mycelia and extracellular antigens. Enzymatic digestion and competitive inhibition tests using different sugar derivatives showed that galactosyl residues with beta linkages were immunodominant for Aspergillus, Geotrichum, and Cladosporium antigens and mannosyl residues with alpha linkages were immunodominant for Mucor antigens.

Surface area and anchorage-dependent growth of Chinese hamster ovary cells

Cell growth can be affected by many factors. For study of the cell responses under various environmental changes, the traditional method using batch cultures may not provide precise answers. It sometimes even leads to misapprehension. A flow system was therefore designed to eliminate the variations in chemical environment during the cell growth. An anchorage Chinese hamster ovary (CHO) cell line was chosen for study under this system. With the help of time-lapse video recording and image analysis, it was found that the exposed surface area (Ae) of Chinese hamster ovary (CHO) cells was significantly affected by the serum concentration (S) in the medium. Cells appeared to be larger when cultivated in medium of low serum content. Comparing the growth rates of cells on different substrata, we have found that, although they were different at a given serum concentration, the growth curves could be correlated to a Monod type equation by replacing the substrate term with AeS. Furthermore, when we studied the effect of density-dependent inhibition of cell growth, we found that there exists a minimum value of AeS required for stimulating cell proliferation. Once AeS falls below this value, cell proliferation stops. These observations seemed to indicate that the interaction between serum factors and cell surface, i.e., AeS, is an important parameter of the growth of CHO cells.

Enzyme-linked immunosorbent assay for detection of molds in cheese and yogurt

An enzyme-linked immunosorbent assay was developed for the detection of molds in dairy products. New Zealand White female rabbits were immunized with .45 mg of partially purified extracellular antigen from freeze-dried culture filtrates of Aspergillus versicolor, Cladosporium herbarum, Geotrichum candidum, Mucor circinelloides, and Penicillium chrysogenum. Blood was drawn at various intervals, and antibodies were separated and purified. Antibody-peroxidase conjugates were prepared with the following ratios being the optimum ones: A. versicolor 10:20; C. herbarum 5:10; G. candidum 1:10; M. circinelloides 5:5; and P. chrysogenum 10:10. The assays were sensitive within a range of 1 ng to 1 microgram/ml, depending on the mold used. Inhibition tests were done for each mold with concentrations of 0 to 5000 micrograms/ml of antigen. The enzyme-linked immunosorbent assay tests for Cladosporium, Geotrichum, and Mucor were only inhibited by antigens from other species of the same genus; whereas there was crossreaction between antibodies and antigens of species of Penicillium and of Aspergillus. Citrate buffer was best for extracting the mold from cheese and yogurt. The extract was adjusted to pH 7.2 and ELISA was performed. Results showed that these molds can be detected in Cheddar and cottage cheeses and yogurt within 2 d, which is before mold growth is visible in these products.