益生菌调节肠道菌群改善功能性消化不良研究进展

功能性消化不良(FD)作为功能性胃肠道疾病的一种,其发病机制尚未明晰。研究表明,胃肠道区系微生物紊乱可能是FD发病的主要机制之一。目前治疗功能性消化不良的方法有限,并存在安全性问题。益生菌是一类一定剂量条件下可以调控胃肠道稳态、营养物质消化吸收及机体能量平衡的活性微生物。以肠道微生物为靶点,通过益生菌调节肠道菌群缓解FD有其潜在优势。本文总结益生菌通过调节肠道菌群改善功能性消化不良的研究进展,为益生菌改善消化不良提供参考依据。     

Comparison of Rapid Methods for Detection of Giardia spp. and Cryptosporidium spp. (Oo)cysts Using Transportable Instrumentation in a Field Deployment

Reliable, sensitive, quantitative, and mobile rapid screening methods for pathogenic organisms are not yet readily available, but would provide a great benefit to humanitarian intervention units in disaster situations. We compared three different methods (immunofluorescent microscopy, IFM; flow cytometry, FCM; polymerase chain reaction, PCR) for the rapid and quantitative detection of Giardia lamblia and Cryptosporidium parvum (oo)cysts in a field campaign. For this we deployed our mobile instrumentation and sampled canal water and vegetables during a 2 week field study in Thailand. For purification and concentrations of (oo)cysts, we used filtration and immunomagnetic separation. We were able to detect considerably high oo(cysts) concentrations (ranges: 15-855 and 0-240 oo(cysts)/liter for Giardia and Cryptosporidium, respectively) in 85 to 300 min, with FCM being fastest, followed by PCR, and IFM being slowest due to the long analysis time per sample. FCM and IFM performed consistently well, whereas PCR reactions often failed. The recovery, established by FCM, was around 30% for Giardia and 13% for Cryptosporidium (oo)cysts. It was possible to track (oo)cysts from the wastewater further downstream to irrigation waters and confirm contamination of salads and water vegetables. We believe that rapid detection, in particular FCM-based methods, can substantially help in disaster management and outbreak prevention.     

Screening of Chinese medicinal herbs for bioactivity against Sitophilus zeamais Motschulsky and Tribolium castaneum (Herbst)

Extracts of 40 species of Chinese medicinal herb from 32 different botanical families were screened for contact, fumigant and feeding-deterrent activities against the two stored-grain insects Sitophilus zeamais and Tribolium castaneum. Thirty Chinese medicinal herbs exhibited insecticidal or feeding-deterrent activities against the two species of insects. Extracts of Artemisia argyi, Dictamnus dasycarpus, Evodia rutaecarpa, Litsea cubeba, Narcissus tazetta var. chinensis, Polygonum aviculare, Rhododendron molle, Sophora flavescens, Stemona sessilifolia, Tripterygium wilfordii, and Torreya grandis were most active.     

Effect of steam cooking on distribution of paralytic shellfish toxins in different tissue compartments of scallops Patinopecten yessoensis

This study investigated the effect of steam cooking on distribution of paralytic shellfish poisoning toxins (PSP-toxins) in scallops Patinopecten yessoensis. Toxins analysis by high-performance liquid chromatography showed that most of the PSP-toxins (>70%) were accumulated in viscera and adductor muscle of the raw scallops. Steam cooking induced significant loss (p < 0.05) of PSP-toxins from viscera (16%), adductor muscle (24%), gill and mantle (11%) while 32% of the toxins were retained inside viscera and adductor muscle. Overall, 51% of PSP-toxins leaked out from scallop tissues during steam cooking. However, there was no significant loss (p > 0.05) of PSP-toxins from gonad. Consumption of viscera was the most significant risk factor for causing PSP, while gonad and scallop soup were the second most significant. A rapid PSP test further verified detectable levels of PSP-toxins in all samples. However, possible interfering substance(s) in adductor muscles and gonads might potentially affect the results from this test.     

Analysis of ingredient functionality and formulation optimization of pasta supplemented with peanut flour

The working peanut pasta formulation range determined from a previous study was used to determine the effects of varying ingredient quantities and processing conditions on the pasta's quality and consumer acceptance. The variables studied were percent peanut flour substituted for durum wheat flour (30%, 40%, and 50%), amount of carrageenan (2.4%, 2.65%, and 2.9%), and drying temperature (60, 74, and 88 °C) on the final cooked pasta quality. Properties measured include color, texture, moisture content, and cooking loss. A home-use sensory test was conducted to determine consumer preferences and the optimum range for variables studied. Color lightness values ranged from 43.53 to 65.02, decreasing (becoming darker) with increased peanut flour level and increased drying temperature. Maximum cutting force for cooked pasta ranged from 1.59 N to 3.22 N, with higher values only for pasta dried at 88 °C. Moisture content ranged from 57.35% to 69.38%, and values decreased as drying temperature increased. Cooking loss ranged from 5.14% to 7.99%, increasing with higher levels of peanut flour and decreasing with higher levels of carrageenan. When prepared with 30% peanut flour and dried at 60 °C, the pasta was lighter in color, higher in moisture, and softer in texture than the varieties dried at higher temperatures and made with higher levels of peanut flour. Response surface analysis of consumer test data revealed that the optimum peanut pasta should contain between 35% and 45% peanut flour and should be dried between 60 and 71 °C; however, the pasta with 30% peanut flour was also a popular sample in the "favorite" categories. Practical Application: Most non-gluten protein fortification studies in durum wheat pasta found decreased firmness of dry and cooked pasta, increased cooking loss, increased stickiness, and darker product color when compared to traditional pasta. Partially defatted peanut flour is a versatile food ingredient and has high protein content. Since the lysine content of peanuts is higher than wheat, peanuts can be used to supplement wheat flour in food preparation. This study found by partially replacing wheat flour with peanut flour and with incorporation of hydrocolloid emulsifier, such as carrageenan or xanthan gum, dough viscosity, and pasta firmness significantly improved. Peanut pasta with high protein content and balanced amino acid profile can help support consumers with a healthy lifestyle.     

Plasma lipid regulatory effect of compounded freshwater clam hydrolysate and Gracilaria insoluble dietary fibre

This study investigates the hypocholesterolemic effects of a diet containing freshwater clam hydrolysate (PX) and insoluble dietary fibre from whole Gracilaria (IDF). Freshwater clam meat and whole dried Gracilaria were separately extracted using hot water. The residual meat was hydrolysed at 50 °C by Protamex to obtain freshwater clam hydrolysate (PX). Levels of triacylglycerol and cholesterol in Sprague–Dawley (SD) rats were compared with those of rats fed diets containing casein and cellulose as a control. Plasma triacylglycerol levels decreased by 65.8%, 27.9%, and 44.3%, respectively, in PX10 (16.6% hydrolysate), IDF10 (13.0% IDF) and compounded PX10/IDF10 groups, while plasma total cholesterol levels decreased by 26.1%, 24.2%, and 17.1%, respectively. In the liver, triacylglycerol levels decreased by 27.6%, 21.0%, and 28.0%, respectively, while total cholesterol levels decreased by 50.0%, 38.5%, and 48.6%, respectively. The compound PX10/IDF10 diet group showed a higher excretion of faecal total cholesterol and bile acids levels than did the other groups.     

Open dumping site in Asian developing countries: a potential source of polychlorinated dibenz-p-dioxins and polychlorinated dibenzofurans

Open landfill dumping areas for municipal wastes in Asian developing countries have recently received particular attention with regard to environmental pollution problems. Because of the uncontrolled burning of solid wastes, elevated contamination by various toxic chemicals including dioxins and related compounds in these dumping sites has been anticipated. In this study, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs) were determined in soils from dumping sites in the Philippines, Cambodia, India, and Vietnam. Residue concentrations of PCDD/Fs and coplanar PCBs in dumping site soils were apparently greater than those in soils collected in agricultural or urban areas far from dumping sites, suggesting that dumping sites are potential sources of PCDD/Fs and related compounds. Observed PCDD/F concentrations in soils from dumping sites in the Philippines and Cambodia were comparable or higher than those reported for dioxin-contaminated locations in the world (e.g., near the municipal waste incinerators and open landfill dumping sites). Homologue profiles of PCDD/Fs in dumping site soils from the Philippines and, to a lesser extent, from Cambodia and India reflected patterns of samples representing typical emissions, while profiles of agricultural or urban soils were similar to those of typical environmental sinks. This result suggests recent formation of PCDD/Fs in dumping site areas and that open dumping sites are a potential source of dioxins in Asian developing countries. Uncontrolled combustions of solid wastes by waste pickers, generation of methane gas, and low-temperature burning can be major factors for the formation of dioxins in dumping sites. Elevated fluxes of PCDD/Fs to soils in dumping sites were encountered in the Philippines, Cambodia, India, and Vietnam-Hanoi, and these levels were higher than those reported for other countries. Considerable loading rates of PCDD/Fs in the dumping sites of these countries were observed, ranging from 20 to 3900 mg/yr (0.12-35 mg TEQ/yr). PCDD/F concentrations in some soil samples from the Philippines, Cambodia, India, and Vietnam-Hanoi exceeded environmental guideline values, suggesting potential health effects on humans and wildlife living near these dumping sites. The estimated intakes of dioxins via soil ingestion and dermal exposure for children were higher than those for adults, suggesting greater risk of dioxin exposure for children in dumping sites. To our knowledge, this is the first comprehensive study on PCDD/Fs contamination in open dumping sites of Asian developing countries. On the basis of the result of this study, we have addressed a new environmental issue that open dumping sites are potential sources of PCDD/Fs and related compounds, and dioxin contamination in dumping sites may become a key environmental problem in developing countries.     

Chronic effects of dietary selenium on juvenile Sacramento splittail (Pogonichthys macrolepidotus)

The chronic effects of dietary selenium (Se) exposure in juvenile Sacramento splittail (Pogonichthys macrolepidotus) were investigated in the laboratory. A total of 960 (40 fish per tank, 3 tanks per diet) 7-month-old juvenile splittail were fed one of eight Purified-Casein diets supplemented with selenized yeast for 9 months in a flow-through system. These diets contained the following: 0.4 (control), 0.7, 1.4, 2.7, 6.6, 12.6, 26.0, and 57.6 mg of Se kg(-1) dry weight. Survival, Se tissue concentration, growth, gross morphology, and liver histopathology were assessed at 5- and 9-month of exposure. Mortalities occurred only in the two highest Se treatments and were accounted for 8.3 and 18.3% at 5-month and 10.0 and 34.3% at 9-month, respectively. Liver and muscle Se concentration were significantly correlated with dietary Se concentration. Fish exposed to 0.4-12.6 mg of Se kg(-1) diets had reached equilibrium in liver Se concentration by 5 month. Splittail fed diets at concentrations > or =26.0 mg of Se kg(-1) had not reached equilibrium in liver, and muscle Se concentrations and grew significantly slower (p < 0.05) at 5- and 9-month exposure. Se-induced deformities were observed in fish fed > or =2.7 mg of Se kg(-1) diets at 5-month and in fish fed > or =0.7 mg of Se kg(-1) diets at 9-month. Fish fed 26.0 and 57.6 mg of Se kg(-1) diets had higher liver lesion scores at 5-month while fish fed 6.6 and 57.6 mg of Se kg(-1) diet had higher liver lesion scores at 9-month. Results indicate that survivals, growth, changes of tissue Se concentrations, and histopathology of juvenile splittail were dose-dependent, but their response thresholds to dietary Se concentrations differed and depended on treatment concentrations and duration of exposure. Chronic exposure to 6.6 mg of Se kg(-1) diet induced deleterious health effects that can potentially impact survival of juvenile splittail.     

Effects of chlorine and pH on efficacy of electrolyzed water for inactivating Escherichia coli O157:H7 and Listeria monocytogenes

The effects of chlorine and pH on the bactericidal activity of electrolyzed (EO) water were examined against Escherichia coli O157:H7 and Listeria monocytogenes. The residual chlorine concentration of EO water ranged from 0.1 to 5.0 mg/l, and the pH effect was examined at pH 3.0, 5.0, and 7.0. The bactericidal activity of EO water increased with residual chlorine concentration for both pathogens, and complete inactivation was achieved at residual chlorine levels equal to or higher than 1.0 mg/l. The results showed that both pathogens are very sensitive to chlorine, and residual chlorine level of EO water should be maintained at 1.0 mg/l or higher for practical applications. For each residual chlorine level, bactericidal activity of EO water increased with decreasing pH for both pathogens. However, with sufficient residual chlorine (greater than 2 mg/l), EO water can be applied in a pH range between 2.6 (original pH of EO water) and 7.0 while still achieving complete inactivation of E. coli O157:H7 and L. monocytogenes.