地方高校基于培养学生创新能力的“食品微生物学”课程教学

食品微生物学是食品类专业的主干课程之一,其教学效果的好坏对该专业人才培养有极其重要的作用。现有的教学方式不能实现食品微生物学作为一门实践性学科应有的作用。在食品微生物学教学改革中,结合学生对食品微生物学的认识,筛选科研素材和新产品,并在理论和实践教学中引导学生开展科研创新训练。通过改革,旨在达到增强学生创新能力、提高学生综合素质和应用微生物学知识进行食品行业的创新和产品升级。     

Limnological changes in a sub‐tropical shallow hypertrophic lake during its restoration: two years of a whole‐lake experiment

1. Lake Rodó is a turbid system, a condition attributed to algal biomass. The proximal source of the eutrophication was stormwater discharges from an ill‐defined urban area. This paper describes an attempt to restore the water quality of Lake Rodó, the first time this has been done in Uruguay. In spring 1996 it was drained, sediments were removed and stream inputs were diverted. Groundwater was used to re‐fill the lake. Due to its high nutrient concentration a re‐circulation system was designed, pumping water from associated pools covered with free‐floating plants. 2. After the lake was refilled, the system was characterized by oxygen saturation or over‐saturation, neutral to basic pH, and high phosphorus, nitrogen and silicate concentrations. Ratios of total nitrogen (TN):total phosphorus (TP) and chlorophyll a (Chl a):TP indicated that phosphorus was the primary limiting nutrient during the period of groundwater supply. Once groundwater pumping had ceased, there was a decrease in TN:TP and Chl a:TP ratios, suggesting N‐limiting conditions prevailed in some periods. 3. Before restoration, the phytoplankton community was dominated year‐round by Planktothrix agardhii; since restoration the community has been more diverse. This change has favoured grazing by mesozooplankton, and the onset of clear‐water phases in spring. 4. Abundant populations of small omnivorous fish maintained a high predation pressure on zooplankton, restricting the abundance of large‐bodied herbivores, which, in turn, allowed an increase in phytoplanton biomass and a decrease in water transparency. Based on this observation, together with the phosphorus concentration and the low abundance of filamentous cyanobacteria compared with previous studies, we suggest that top‐down control has played a key role in increasing transparency in Lake Rodó. 5. A nutrient reduction programme, by the mechanical harvest of floating plants, and a removal of small omnivorous fishes and stocking strictly with piscivores, could be key factors in the achievement of a stable clear‐water phase. However, if blooms of Microcystis or other similar genera occur in summer, additional measures (e.g. reduction of the hydraulic residence time) will be needed to improve water transparency. Copyright © 2001 John Wiley & Sons, Ltd.     

Modulation of peripheral markers of the serotoninergic system in healthy horses

To evaluate the changes in plasma and platelet serotonin (5-HT) as markers of the serotoninergic system in equines, 5-HT content was measured by high performance liquid chromatography (HPLC) in deproteinized plasma obtained from peripheral blood samples of 12 clinically healthy horses, before and after feeding. 5-HT was measured in platelet rich plasma (PRP) and in platelet poor plasma (PPP). 5-HT in platelets (p5-HT) was obtained by subtracting free 5-HT in PPP (f5-HT) from 5-HT in PRP. After food ingestion, significant increases in p5-HT and f5-HT (p < 0.001), and no changes in the f5-HT/p5-HT ratio were recorded. Increase in the total circulating 5-HT might account both for initiating peristaltic activity and for increasing the f5-HT levels. Augmented 5-HT uptake by platelets could reflect the hypothetical increased activity of the serotoninergic neurons. Besides showing the feasibility to obtain f5-HT and p5-HT through HPLC determination of 5-HT in PRP and PPP equine plasma, these findings are consistent with the postulation that 5-HT is released from enterochromaffin cells following a mechanical and chemical stimulation.     

Plant Species Composition and Forage Production 14 Yr After Biosolids Application and Grazing Exclusion

This paper examines the effects of a single surface application of biosolids (at 20 dry Mg ha^{? 1}) on plant species composition, forage quality and quantity, and C stocks after 14 yr of rest in rangelands of the Central Interior of British Columbia. More than two times the aboveground biomass of grasses and the percent cover of plant litter were found in the biosolids treatment relative to the control, along with reductions in bare soil and microbiotic crust cover. Significantly greater plant uptake of all macronutrients (C, N, P, K, S, Ca, and Mg); most micronutrients (B, Cu, Mn, Mo, and Zn); and Al occurred in the biosolids treatment. P and Cu were the only two nutrients to be more concentrated in the biosolids-treated forage relative to the control forage, while N, Mg, and protein were more concentrated in the control forage. No significant difference in forage digestibility was found between biosolids and control treatments. Bluebunch wheatgrass, the late-seral native grass species, had significantly increased cover and aboveground biomass in the biosolids treatment relative to the control; however, between 2006 and 2016, non-native Kentucky bluegrass had reached > 25% cover in the biosolids plots, perhaps restricting the full recovery of bluebunch wheatgrass. Our findings indicate that biosolids application to ungrazed rangeland can increase long-term forage production and reduce bare soil. However, at our study site biosolids application also led to a long-term shift in the plant community composition away from the late-seral (i.e., bluebunch wheatgrass) trajectory, and the effects of this shift on rangeland health and productivity require further investigation.     

中华鼢鼠生物学特性的研究

通过研究中华鼢鼠生物学特性，其食性食量125g／d，每个洞内食物存放平均750g；解剖观察，怀孕胚胎2-4个，平均3．38个，雌雄比为53．16：46．84。     

利用Java技术建立草地农业信息资源数据库

草地农业信息资源数据库利用Java技术和Web方式实现，分析了用户需求和系统优势，阐明了数据库的设计思路、结构及系统实现方法。     

Towards a risk-based surveillance for Trichinella spp. in Danish pig production

Increasing demands for cost-effectiveness in surveillance for human health hazards from animal origins can be met by introducing risk-based principles. This e.g. implies targeting subpopulations with higher risk of infection compared to the whole population. Furthermore, historical data from surveillance can be collated and used to assess future risk of infection. To demonstrate the effectiveness of combining these two approaches, we used a model called “Discounting historical evidence”. It depends mainly on the annual risk of introduction (PIntro) and the surveillance system sensitivity (SSe) (ability to detect infection if present). The model implies simulations that reiterate for a number of years. For each year the output is updated with the confidence on absence in infection. Trichinella spiralis infection in pigs is used as an example. In Denmark, more than 20 million pigs are tested annually. Despite more than 70 years of testing no pigs have been found positive for Trichinella. Hence, PIntro is low. SSe can be estimated from the maximum number of infected carcasses expected under the specified design prevalence, and the sensitivity of the test applied. According to our assessment, the current prevalence of Trichinella in Danish pigs is less than one case per million, which we interpret as negligible risk. Based on this, a risk-based surveillance programme for Trichinella is designed that targets all out-door reared pigs as well as all sows and boars (current total 610,000 slaughtered annually). These subpopulations are judged to have higher risk of getting Trichinella. Again, SSe and PIntro are estimated and the model results show that risk-based surveillance can be applied without jeopardizing human health. Finally, we incorporate wildlife surveys and test quality assurance in the programme. The results of the simulation model were included in an application to the European Commission concerning Denmark's status as a region with negligible risk of Trichinella. In July 2007, the European Commission granted status as “negligible risk” to Danish pigs and pork.     

Risk factors associated with faecal shedding of verocytotoxin-producing Escherichia coli O157 in eight known-infected Danish dairy herds

A risk-factor study was performed in eight dairy herds found to excrete verocytotoxin-producing Escherichia coli (VTEC) O157 in a former prevalence study. Associations between excretion of VTEC O157 and management factors such as housing and feeding were analysed in a generalised linear mixed model. The animals were stratified in three age groups and sampled four times during 1 year. The risk of excreting VTEC O157 was higher among weaned calves than non-weaned calves. Among the calves aged 1–4 months, the risk was reduced if the calf had suckled colostrum from the mother or if the calf had stayed >2 days with the mother after calving. Calves aged 5–24 months that had been moved within the last 2 weeks had a higher risk, but risk was reduced if fed barley silage. Cows fed grain or molasses had a higher risk of excreting VTEC O157.     

Bacteriophages as antimicrobial agents against major pathogens in swine: a review

In recent years, the development of antibiotic resistant bacteria has become a global concern which has prompted research into the development of alternative disease control strategies for the swine industry. Bacteriophages (viruses that infect bacteria) offer the prospect of a sustainable alternative approach against bacterial pathogens with the flexibility of being applied therapeutically or for biological control purposes. This paper reviews the use of phages as an antimicrobial strategy for controlling critical pathogens including Salmonella and Escherichia coli with an emphasis on the application of phages for improving performance and nutrient digestibility in swine operations as well as in controlling zoonotic human diseases by reducing the bacterial load spread from pork products to humans through the meat.