“厌氧消化实验”在资源循环科学与工程专业人才培养中的开展

阐述了资源循环新兴产业背景下“资源循环科学与工程”专业人才迫切需求,剖析了新工科背景下常州市某高校对该类专业人才培养的关键举措。深入探讨“资源循环专业实验”课程在人才培养过程中开设的必要性,并以“厌氧消化实验”为例详细介绍了综合实验课程具体开展内容及取得的成效,对培养资源循环领域高素质复合型人才具有借鉴意义。

通过厌氧消化实验探讨《微生物学》综合性实验教学

通过对厌氧消化实验教学过程的改革研究,以提高学生实践能力和创新精神为目的,探讨了微生物学综合性实验教学的新方法。

探究唾液对淀粉的消化实验教学设计

本文以北师大版《生物学》教材七年级下册第八章第2节《食物的消化和营养物质的吸收》中“探究唾液对淀粉的消化作用”教学内容进行教学设计。对实际课堂中设计细节和自然生成问题进行了反思。

基于体外消化实验评估辣椒中常见金属元素的膳食健康风险

[背景]有害金属对农产品的污染及产生的健康风险已成为社会关注的热点,辣椒作为我国主要的经济农产品,对其进行健康风险评价必不可少。[目的]通过探讨我国辣椒主产区域不同品种辣椒中常见金属元素的富集情况,基于金属的生物可给性评估其对不同特征人群的膳食健康风险。[方法]通过随机采样法,从市场上采购我国辣椒主产区的干辣椒样品,将采集样品按辣椒形态结构将辣椒品种分为小辣椒、大板椒、二荆条、子弹头和灯笼椒,共采集辣椒样品667份。检测其中常见6种金属元素[砷(As)、镉(Cd)、铅(Pb)、镍(Ni)、铜(Cu)和锌(Zn)]含量,使用统计学方法进行差异性比较;采用体外胃肠模拟消化实验,计算辣椒中金属元素生物可给性并对其健康风险进行评估。[结果]辣椒中重金属Cd和Ni含量超过我国限值标准,超标率分别为6.1%和22.7%,其余金属含量处于安全范围;不同辣椒品种间As、Cd、Pb、Cu和Zn含量存在差异(P<0.05);辣椒中6种金属元素生物可给性依次为As(57.9%)>Cd(43.07%)>Zn(42.74%)>Pb(38.04%)>Ni(31.97%)>Cu(31.4%);基于生物可给性,采集辣椒中6种金属元素含量在P_(50)时,辣椒中金属的危险系数依次为Cu>Cd>As>Ni>Zn>Pb;在P_(90)时,危险系数依次为Cd>As>Cu>Ni>Zn>Pb;单一金属元素的危险系数及复合金属元素的总目标危险系数均小于1,且成人高于儿童。[结论]在所采集的辣椒样品中,单一金属元素及多种金属元素非致癌性健康风险均处于安全范围,基于胃肠阶段的生物可给性,健康风险进一步降低。

柞蚕丝素蛋白对大鼠体内消化指标的影响

该文探究柞蚕丝素蛋白的营养价值。采用化学和生物学方法测定并分析柞蚕丝素蛋白的5项消化指标(表观消化率、真消化率、蛋白质功效比值、生物价和蛋白质净利用率)以及对大鼠体内器官的相关影响。用柞蚕丝素蛋白饲料进行喂养实验,采用美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)的方法进行给予饲料。把25只雄性SD大鼠放入代谢笼里进行单笼饲养,5只为一个实验组。饲养一段时间后,采集尿液和粪便进行定氮,计算相关指标。结果表明,高蛋白组真消化率(true digestibility,TD)和表观消化率(apparent digestibility,AD)分别为(54.65±4.00)%和(35.83±2.60)%、生物价(biological value,BV)为98.13±1.74、蛋白质净利用率(net protein utilization,NPU)为(56.67±2.93)%、蛋白质功效比值(protein efficiency ratio,PER)为-0.99±0.43;低蛋白组TD和AD分别为(57.77±5.08)%和(33.36±1.19)%、BV为96.35±2.66、NPU为(60.40±5.65)%、PER为(-0.99±0.43)。结果表明,高蛋白组表观消化率偏低、真消化率偏低,功效比值为负值。28 d喂养实验结束后,对大鼠进行解剖观察,发现大鼠主要器官无病变,血清指标均在正常范围之内,推测柞蚕丝素蛋白可以保存相应肌肉和能量,减少部分多余脂肪量。

纳米微晶纤维素-棕榈油的Pickering乳化液的制备及体外消化行为

以市售棕榈油(熔点为5℃)为乳化对象,利用棉短绒来源的1%纳米微晶纤维素(NCC)水分散液对其进行Pickering乳化(水相∶油相=7∶3,v∶v),分析不同酸解时间制备的NCC的乳化效果;同时,以游离脂肪酸的释放量为指标,研究NCC乳化液在模拟胃肠道中的消化行为。结果表明,酸解时间为3.0 h的NCC的Pickering乳化效果最好,不同酸解时间的NCC的Pickering乳液粒径均主要集中于1～10μm。NCC乳化液体外消化实验表明:1%的NCC形成的乳化液在肠液消化2 h时的游离脂肪酸释放量为830μmol/L,同样条件下,棕榈油对照组的游离脂肪酸释放量为480μmol/L。NCC含量越高,游离脂肪酸释放量越高,表明NCC乳化有助于脂肪的消化。纳米微晶纤维素的Pickering乳化特性在功能性脂肪酸及脂性活性物质的承载与传递中具有潜在的应用。

方竹笋膳食纤维作为益生元对乳酸菌生长的影响

为了探究竹笋膳食纤维(bamboo shoot dietary fiber,BSDF)作为益生元对乳酸菌生长的影响,以常见益生元菊粉为对照,检测了BSDF在模拟胃肠液中的抗消化性,以及对乳酸菌L1(Lactobacillus fermentum)、L2(Lactobacillus plantaum)生长过程中pH值、总酸含量和生长曲线的影响。结果表明,BSDF中总膳食纤维、不溶性膳食纤维、可溶性膳食纤维含量分别为64.90%、58.12%、6.78%,相对含量较高的单糖有葡萄糖(39.72%)、阿拉伯糖(12.77%)、木糖(12.69%)。BSDF在胃肠液中具有一定的抗消化性,模拟消化6 h后,BSDF在人工胃液(pH=3.5)和人工肠液(pH=7)的水解率分别为15.54%、31.08%,均低于菊粉对照组。对于乳酸菌L1,随着BSDF添加量的增加,培养基中的菌群浓度不断增加,BSDF相比于菊粉更有利于乳酸菌L1生长。对于乳酸菌L2,随着BSDF添加量的增加,总酸含量逐渐增大,乳酸菌的益生效应也随之增强。该研究可为BSDF作为益生元的开发利用提供理论参考。

实验性消化道溃疡的iIEL及其亚群(Thy1^-)的T_H1型细胞因子水平变化及细胞毒活性

目的 了解消化道溃疡肠上皮间淋巴细胞 (iIEL)及其亚群 (Thy1- )的TH1型细胞因子的分泌和细胞毒活性。方法 利用水浸限制刺激方法诱发小鼠消化道溃疡模型 ,应用细胞溶解法分离Thy1- iIEL ,采用ELISA法、Northern斑点杂交法和生物学测定法分别检测iIEL及其亚群 (Thy1- )的TH1型细胞因子 (IFN γ、IL 2和TNF α)分泌、mRNA表达和iIEL细胞毒活性。结果 给予水浸限制刺激后 ,iIEL培养上清中IFN γ、IL 2的含量于第 3～ 4天达高峰 ,第 6天仍维持较高水平。IFN γ和IL 2的mRNA表达水平与测得的细胞因子水平呈相应变化。Thy1- iIEL亚群培养上清中 ,IFN γ和IL 2的含量与正常对照差异未见显著性。iIEL的杀伤活性在水浸限制刺激后第 2天达高峰 ,1周后恢复正常。结论 应激性溃疡发生后一定时间内 ,iIEL的TH1型细胞因子IFN γ、IL 2和TNF α的mRNA表达水平升高 ,IFN γ、IL 2分泌水平增加 ,细胞毒活性增强 ,这一变化可能对肠道功能具有保护作用。TH1型细胞因子分泌水平升高可能不是主要来自于Thy1- 亚群。

Comparison between empirical prokinetics, Helicobacter test-and-treat and empirical endoscopy in primary-care patients presenting with dyspepsia: A one-year study

AIM： To investigate the optimal strategy to treat dyspeptic patients in primary care. METHODS： Dyspeptic patients presenting to primary care outpatient clinics were randomly assigned to- （1） empirical endoscopy, （2） H pylori test-and-treat, and （3） empirical prokinetic treatment with cisapride. Early endoscopy was arranged if patients remained symptomatic after 2 wk. Symptom severity, quality-of-life （SF-36） as well as patient preference and satisfaction were assessed. All patients underwent endoscopy by wk 6. Patients were followed up for one year. RESULTS： Two hundred and thirty four patients were recruited （163 female, mean age 49）. 46% were H pylori positive. 26% of H pylori tested and 25% of empirical prokinetic patients showed no improvement at wk 2 follow-up and needed early endoscopy. 15% of patients receiving empirical cisapride responded well to treatment but peptic ulcer was the final diagnosis. Symptom resolution and quality-of-life were similar among the groups. Costs for the three strategies were HK$4343, $1771 and $1750 per patient. 66% of the patients preferred to have early endoscopy. CONCLUSION： The three strategies are equally effective. Empirical prokinetic treatment was the least expensive but peptic ulcers may be missed with this treatment. The H pylori test-and-treat was the most cost-effective option .

Effect of synbiotics on intestinal microflora and digestive enzyme activities in rats

AIM: To investigate the effect of synbiotics, i.e. probiotics and prebiotics mixture, on the gut microbial ecology and digestive enzyme activities in rats. METHODS: Forty-eight SD rats weighing about 280 g were used in this study. Rats were divided into three groups according to the contents of probiotics and prebiotics mixture in the feed as control, low and high dose groups. The duration of the experiment was 8 wk. RESULTS: Compared with the control group, thefecal Lactobacillus and Bifidobacterium counts were significantly increased and the fecal Coliform organism counts were markedly reduced in the low and high dose groups. Concerning the digestive enzyme activity of jejunum, only lactase activity increased in low dose group. However, significant increase of lipase, lactase, sucrase, and isomaltase activities were observed in high dose group.CONCLUSION: Intake of low and high dosages of probiotics and prebiotics mixture significantly improved the ecosystem of the intestinal tract by increasing the probiotics population and digestive enzyme activities in rats.

Effects of killing Helicobacter pylori quadruple therapy on peptic ulcer: A randomized double-blind clinical trial

AIM: To study the therapeutic efficacy of a Chinese and Western integrated regimen, killing Helicobacter pylori quadruple therapy on H pylori-associated peptic ulcers(PU).METHODS: With prospective and double-blind controlled method, seventy-five active PU patients with H pylori infection were randomized to receive one of the following three regimens: (1) new triple therapy (group A:lansoprazole 30 mg qd, plus clarithromycin 250 mg bid,plus amoxycillin 500 mg tid, each for 10 d); (2) killing Hp quadruple therapy(group B: the three above drugs plus killing H pylori capsule 6 capsules bid for 4 wk) and (3)placebo(group C: gastropine 3 tablets bid for 4 wk).H pylori eradication and ulcer healing quality were evaluated under an endoscope 4 wk after treatment. The patients were followed up for 5 years.RESULTS: Both the healing rate of PU and H pylori eradication rate in group B were significantly higher than those in group C (100% and 96.4% vs 20% and 0%,respectively, P＜0.005), but there was no significant difference compared to those in group A (88% and92%, P＞0.05). The healing quality of ulcer in group B was superior to that in groups C and A (P＜0.05). The recurrence rate of PU in group B (4%) was lower than that in group A (10%) and group C (100%, P＜0.01).CONCLUSION: Killing Helicobacter pylori quadruple therapy can not only promote the eradication of H pylori and healing quality of ulcer but also reduce recurrence rate of ulcer.

CT colonography after incomplete colonoscopy in subjects with positive faecal occult blood test

AIM： To report our experience with computed tomography colonography （CTC） systematically performed in subjects with positive faecal occult blood test （FOBT） and an incomplete colonoscopy in the setting of a population-based screening for colorectal cancer （CRC）. METHODS： From April 2006 to April 2007, 43 290 individuals （age range 50-70） who adhered to the regional screening program for the prevention of CRC underwent immunochemical FOBT. FOBT was positive in 1882 subjects （4.3%）. 1463 （77.7%） of these subjects underwent colonoscopy, 903 performed in a single center. Of 903 colonoscopies 65 （7.2%） were incomplete. Forty-two of these subjects underwent CTC. CTC was performed with a 16-MDCT scanner after standard bowel prep （polyethyleneglycole） in both supine and prone position. Subjects whose CTC showed polyps or masses were referred to the endoscopist for repeat colonoscopy under sedation or underwent surgery. Perlesion and per-segment positive predictive values （PPV） were calculated. RESULTS： Twenty-one （50%） of 42 CTCs showed polyps or masses. Fifty-five of these subjects underwent a repeat colonoscopy, whereas 2 subjects underwent surgery for colonic masses of indeterminate nature. Four subjects refused further examinations. CTC correctly identified 2 colonic masses and 20 polyps. PPV for masses or polyps greater than 9 mm was of 87.5%. Per-lesion and per-segment PPV were, respectively, 83.3% and 83.3% for polyps greater or equal to 10 mm, and 77.8% and 85.7% for polyps of 6-9 mm. CONCLUSION： In the context of a screening program for CRC based on FOBT, CTC shows high per-segment and per-lesion PPV for colonic masses and polyps greater than 9 mm. Therefore, CTC has the potential to become a useful technique for evaluation of the non visualized part of the colon after incomplete colonoscopy.

L-arginine-induced experimental pancreatitis

Despite medical treatment,the lethality of severe acute pancreatitis is still high (20-30%).Therefore,it is very important to find good animal models to characterise the events of this severe disease.In 1984,Mizunuma et al. developed a new type of experimental necrotizing pancreatitis by intraperitoneal administration of a high dose of L-arginine in rats.This non-invasive model is highly reproducible and produces selective,dose-dependent acinar cell necrosis. Not only is this a good model to study the pathomechanisms of acute necrotizing pancreatitis,but it is also excellent to observe and influence the time course changes of the disease.By writing this review we iluminate some new aspects of cell physiology and pathology of acute necrotizing pancreatitis.Unfortunately,the reviews about acute experimental pancreatitis usually did not discuss this model. Therefore,the aim of this manuscript was to summarise the observations and address some challenges for the future in L-arginine-induced pancreatitis.

Disturbance of hepatic and intestinal microcirculation in experimental liver cirrhosis

AIM: To analyze hepatic, mesenteric and mucosal microcirculation and leukocyte-endothelium interaction (LEI) in a rat model with liver cirrhosis.METHODS: Hepatic cirrhosis was induced in Wistar rats by gavage with carbon tetrachloride, and intravital videomicroscopy was performed in liver, mesentery and small intestine mucosa. Special emphasis is given on microcirculatory and morphometric changes during cirrhotic portal hypertension.RESULTS: LEI was influenced significantly in the cirrhotic liver but not in the gut. Blood flow measurement showed significant differences among liver, main mesenteric vessels and the mucosa. The results of our study indicate that liver cirrhosis leads to alterations in hepatic and mesenteric blood flow but not in mucosal blood flow.CONCLUSION: The enhanced inflammatory response in hepatic microvessels may be caused by a decrease of antithrombin Ⅲ levels and could be responsible for disturbances of organ pathology.

EFFECTS OF ACUTE HYPOGLYCEMIA ON THE OREXIN SYSTEM IN RAT

Objective To evaluate the effects of acute glucose level changes on expression of prepro-orexin, orexin 1 receptor (OX1R) and orexin 2 receptor (OX2R) mRNA in rat hypothalamus tissue and pancreatic islets cells. Methods Thirty adult male Wistar rats were randomly divided into three equal groups (n = 10). The acute hypoglycemia rat model was induced by a single subcutaneous injection of insulin. Twenty acute hypoglycemia rats were divided into group B and group C. Group B was allowed to eat freely, while group C was food-deprived. Control rats were injected the same volume of saline. The effect of glucose levels (2.8 mmol/L and 8.3 mmol/L) on pancreatic islet cell orexin system was detected in pancreas islet cell cultured in vitro. The expression of prepro-orexin and OXR mRNA was examined in rat hypothalamus tissue and pancreatic islets cell cultured in vitro using reverse transcription-polymerase chain reaction (RT-PCR). Results Expression of orexin mRNA increased about 150% for the food-deprived hypoglycemia rats in comparison with control group (P < 0.01), whereas expression of OX1R mRNA decreased up to 30% (P < 0.01). However, expression of OX2R mRNA was unchanged in comparison with control group. In vitro, after incubation with 2.8 mmol/L glucose for 6 hours, the expression of prepro-orexin mRNA increased 2 times in rat pancreas islet cells in comparison with 8.3 mmol/L glucose group (P < 0.01). But the expression of OX1R mRNA was not sensitive to acute glucose fluctuation.Conclusions Orexin in rat hypothalamus is stimulated by decline in blood glucose and inhibited by signals related to feeding. Moreover, glucose plays a role in modulating the gene expression of prepro-orexin in rat pancreatic islet cells.

Proteinases from the digestive organs of black carp （Mylopharyngodon piceus）： Partial characterization and protein digestibility in vitro

A series of experiments based on electrophoretical and biochemical assays were conducted to partially characterize proteinases present in the hepatopancreas and intestine of black carp （Mylopharyngodon piceus）, and investigate enzymatic activity and protein digestibility in vitro. Casein digestion assays revealed the presence of acidic proteinases with optimum activity in the range of pH 2.0-2.5 and alkaline proteinases with significantly higher activities both in the range of pH 8.1-8.6 and near pH 9.5. The inhibition and substrate specificity assays showed that trypsin and chymotrypsin are the main active components of the alkaline proteinases. The SDS-substrate-PAGE showed that the crude extract of black carp intestine had eight types of alkaline proteinases with the molecular mass range of 27.5-78.5 kDa while the crude extract of black carp hepatopancreas had six types of alkaline proteinases with the molecular mass range of 27.5-78.5 kDa. These enzymes were characterized as trypsin （27.5 kDa, 30.1 kDa）, chymotrypsin （40.5 kDa, 42.5 kDa）, serine proteinases （32.1 kDa, 33.2 kDa） and non-serine proteinase （61.5 kDa, 78.5 kDa）.In vitro protein digestibility assays showed that black cardcan be able to utilize a wider range of proteins.

Improvement of mount preparations in showing myenteric nerve plexus from intestines of mice

Objective: The whole mount preparations of digestive tract is an effective experimental way to study the appearance and distribution of nerve plexus in digestive tract. Although myentric nerve plexus preparations technique was reported very early. But we have done experiment over and over during our research work in order to improve this traditional method and to meet the needs of our research work, we made some progresses in regular mount preparations after many experiments, which helped offer better situation in observing myentric nerve plexus. Methods: Five healthy male adult Kunming mice (20-30 g in weight) were used in this study. After intraperitoneal injection of muscle relaxant, with dislocation of cervical vertebra method, the abdominal cavity was exposed through abdominal median incision. After several steps of mount preparations the mucous layer and longitudinal muscle layer mount preparations with myentric nerve plexus were stripped under anatomical microscope. Immunohistochemical staining was also used in our study. Results: The mount preparation samples with myentric nerve plexus from intestines of mice showed positive SP immunoreaction. The positive cells were dark brown. Many of the cytons appeared circular and oval, while some appeared triangular or irregular. Conclusion: Our improved method is really a good method to show enteric nerve plexus. The method has many advantages and is particularly applied to small animals such as Kunming mice and BALB/c mice, weighing from 20 g to 30 g.

Comparative Utilization of Different Fibre Feedstuffs by Weaning/Growing Pigs in the Tropics

This study was conducted to investigate the effect of feeding different fibre feedstuffs on the performance, nutrient utilization and economics of production of weaning/growing pigs. Five fibre feedstuffs--palm kernel cake （PKC）, wheat offal （WO）, corn bran （CB）, rice bran （RB） and brewers＇ dried grain （BDG） were used at 25% in each of the five experimental diets that were formulated in this study. Twenty weaner pigs （12.75 ± 0.6 kg） were used for the growth study while 15 pigs （14.95 ± 0.57 kg） were used for the digestibility study. The design of the experiment was completely randomized. The results of the study showed that the performance of the experimental animals were significantly influenced （P 〈 0.05） by the dietary treatments. The apparent digestibility of the crude protein, crude fiber and ether extract showed significant differences （P 〈 0.05） while there was no significant difference （P 〉 0.05） in the apparent digestibility of their dry matter, ash and nitrogen free extract. The diet that contained WO had the best growth response and apparent nutrient digestibility. Results of economics of production also showed that diet with WO gave the best （P 〈 0.05） value in feed cost/＇kg gain and net profit/animal. It can be concluded from this study that although all the animals fed the different fibre feedstuffs performed satisfactorily on all the parameters monitored, but for optimum growth, apparent nutrients digestibility and economics of production. WO should be used as a fibre feedstuff in the diets of weaning/growing pigs in the tropics.