Network Formation in Gluten‐Free Bread with Application of Transglutaminase     

Michelle M. Moore  Meike Heinbockel  Peter Dockery  H. M. Ulmer  Elke K. Arendt 《Cereal Chemistry》2006,83(1):28-36

One of the main problems associated with gluten‐free bread is obtaining a good structure. Transglutaminase (TGase), an enzyme that catalyzes acyl‐transfer reactions through which proteins can be cross‐linked could be a way to improve the structure of gluten‐free breads. The objective of this study was to evaluate the impact of TGase at different levels (0, 0.1, 1, and 10 U of TGase/g of protein) on the quality of gluten‐free bread. The recipe consisted of white rice flour (relative amount: 35), potato starch (30), corn flour (22.5), xanthan gum (1), and various protein sources (skim milk powder [SMP] [12.5], soya flour, and egg powder). The influence of the various proteins in combination with the different addition levels of TGase on bread quality (% bake loss, specific volume, color, texture, image characteristics, and total moisture) was determined. Confocal laser‐scanning microscopy (CLSM) was used to evaluate the influence of TGase on the microstructure of the bread. Baking tests showed that TGase had an effect on the specific volume of the bread. For instance, the SMP bread with 10 U of enzyme contained the most compact structure, which was reflected in the crumb texture profile analysis results (highest values) (P < 0.05), digital image analysis (highest level of cells/cm²) (P < 0.05), and CLSM micrographs (network formation). Finally, it can be concluded that it is possible to form a protein network in gluten‐free bread with the addition of TGase. However the efficiency of the enzyme is dependent on both the protein source and the level of enzyme concentration.  相似文献   

Nitrogen alters carbon dynamics during early succession in boreal forest     

Steven D. Allison  Tracy B. Gartner  Michelle C. Mack  Kathleen Treseder 《Soil biology & biochemistry》2010,42(7):1157-1164

Boreal forests are an important source of wood products, and fertilizers could be used to improve forest yields, especially in nutrient poor regions of the boreal zone. With climate change, fire frequencies may increase, resulting in a larger fraction of the boreal landscape present in early-successional stages. Since most fertilization studies have focused on mature boreal forests, the response of burned boreal ecosystems to increased nutrient availability is unclear. Therefore, we used a nitrogen (N) fertilization experiment to test how C cycling in a recently-burned boreal ecosystem would respond to increased N availability. We hypothesized that fertilization would increase rates of decomposition, soil respiration, and the activity of extracellular enzymes involved in C cycling, thereby reducing soil C stocks. In line with our hypothesis, litter mass loss increased significantly and activities of cellulose- and chitin-degrading enzymes increased by 45-61% with N addition. We also observed a significant decline in C concentrations in the organic soil horizon from 19.5 ± 0.7% to 13.5 ± 0.6%, and there was a trend toward lower total soil C stocks in the fertilized plots. Contrary to our hypothesis, mean soil respiration over three growing seasons declined by 31% from 78.3 ± 6.5 mg CO₂-C m⁻² h⁻¹ to 54.4 ± 4.1 mg CO₂-C m⁻² h⁻¹. These changes occurred despite a 2.5-fold increase in aboveground net primary productivity with N, and were accompanied by significant shifts in the structure of the fungal community, which was dominated by Ascomycota. Our results show that the C cycle in early-successional boreal ecosystems is highly responsive to N addition. Fertilization results in an initial loss of soil C followed by depletion of soil C substrates and development of a distinct and active fungal community. Total microbial biomass declines and respiration rates do not keep pace with plant inputs. These patterns suggest that N fertilization could transiently reduce but then increase ecosystem C storage in boreal regions experiencing more frequent fires.  相似文献   

Identification and localization of food-source microbial nucleic acids inside soil nematodes     

Amy M. Treonis  E. Harlan Michelle  Cecilia A. O’Leary  Erin E. Austin  Carolyn B. Marks 《Soil biology & biochemistry》2010,42(11):2005-2011

Microorganisms (e.g., prokaryotes, fungi) are food sources for soil nematodes, but they can also be potential mutualists or pathogens. Understanding the linkages between microorganism and invertebrate diversity in soils requires the ability to distinguish between these microbial roles. We tested the potential of a taxon-specific fluorescent in situ hybridization (FISH) procedure for identifying and localizing microbial rRNA within the bodies of soil nematodes. Our objective was to determine whether the rate of digestion permitted detection and identification of food-source nucleic acids within the nematode digestive system (i.e., pharynges, intestines) before their breakdown. First, using laboratory cultures of Caenorhabditis elegans maintained on Escherichia coli, we were able to localize bacterial rRNA throughout the nematode pharynx with the universal bacterial-probe EUB338, although never in the intestines. Second, we applied the fungal rRNA probe FR1 to Aphelenchus avenae cultured on the fungus Rhizoctonia solani. We were unable to detect fungal rRNA within these nematodes, and it appears that this material may be digested rapidly. Next, we applied our technique to nematodes extracted directly from soils. We were able to localize bacterial rRNA within the pharynges of bacterial-feeding species of nematodes from desert soils. We also localized archaeal rRNA using the probe ARC344. Finally, application of EUB338 to desert soil nematodes revealed the presence of bacteria in the intestines of some nematodes and within the ovary of a single nematode. This technique has great potential for use in understanding the feeding behavior of bacterial-feeding soil nematodes and in studies of nematode:bacterial relationships.  相似文献   

Bird‐repellent effects on bait efficacy for control of invasive mammal pests          下载免费PDF全文

Phil Cowan  Sam Brown  Guy Forrester  Lynn Booth  Michelle Crowell 《Pest management science》2015,71(8):1075-1081

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Contagious Equine Metritis Within the United States: A Review of the 2008 Outbreak     

Stacy Luddy  Michelle Anne Kutzler 《Journal of Equine Veterinary Science》2010

Contagious equine metritis (CEM) is a reportable foreign animal disease in the United States caused by the organism Taylorella equigenitalis. Import and export regulations regarding transport of horses into the United States from countries which either have a high prevalence of CEM or those that trade freely with countries having a high prevalence of CEM have failed to prevent the 2008 outbreak, which has not yet been traced to the original horse. It is important to recognize the clinical signs of acute CEM infections (endometritis, infertility, and abortion) to prevent further outbreak of disease. With early recognition, proper testing, and quarantine measures, the outbreaks and economic losses to the United States can be kept to a minimum. However, there are certain characteristics of the disease that are difficult to diagnose and control, such as the ability of the organism to infect an animal without creating clinical signs and the difficulty in culturing it. A review of the transmission, clinical signs, diagnostic methods, treatment, and prevention of CEM as well as a brief summary of the 2008 outbreak of CEM within the United States has been discussed in this article.  相似文献   

Carbohydrate Alimentary Overload Laminitis     

Christopher C. Pollitt  Michelle B. Visser 《Veterinary Clinics of North America: Equine Practice》2010

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Increased risk of chronic wasting disease in Rocky Mountain elk associated with decreased magnesium and increased manganese in brain tissue     

Stephen N. White  Katherine I. O’Rourke  Thomas Gidlewski  Kurt C. VerCauteren  Michelle R. Mousel  Gregory E. Phillips  Terry R. Spraker 《Canadian journal of veterinary research》2010,74(1):50-53

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of Rocky Mountain elk in North America. Recent studies suggest that tissue and blood mineral levels may be valuable in assessing TSE infection in sheep and cattle. The objectives of this study were to examine baseline levels of copper, manganese, magnesium, zinc, selenium, and molybdenum in the brains of Rocky Mountain elk with differing prion genotypes and to assess the association of mineral levels with CWD infection. Elk with leucine at prion position 132 had significantly lower magnesium levels than elk with 2 copies of methionine. Chronic wasting disease-positive elk had significantly lower magnesium than control elk. The incorporation of manganese levels in addition to magnesium significantly refined explanatory ability, even though manganese alone was not significantly associated with CWD. This study demonstrated that mineral analysis may provide an additional disease correlate for assessing CWD risk, particularly in conjunction with genotype.  相似文献   

Recent Advances in Canine Gastrointestinal Ultrasonography     

Michelle H. Fabiani 《Advances in Small Animal Medicine and Surgery》2010,23(11):1-3

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CD3+ and BLA.36+ cells do not occur in the epidermis and adnexal epithelia of normal skin from the dorsolateral trunk of cats     

Michelle M. Tranchina  Danny W. Scott  Sean P. McDonough 《Journal of Feline Medicine and Surgery》2010,12(10):790-793

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The resilience of long and short food chains: a case study of flooding in Queensland,Australia     

Kiah Smith  Geoffrey Lawrence  Amy MacMahon  Jane Muller  Michelle Brady 《Agriculture and Human Values》2016,33(1):45-60

This paper provides new insights into the food security performance of long and short food chains, through an analysis of the resilience of such chains during the severe weather events that occurred in the Australian State of Queensland in early 2011. Widespread flooding cut roads and highways, isolated towns, and resulted in the deaths of people and animals. Farmlands were inundated and there were food shortages in many towns. We found clear evidence that the supermarket-based (long) food chain delivery system experienced significant difficulties in supplying food to flood-affected towns. In contrast, more localized (short) food supply chains—which relied upon supply from growers in peri-urban areas and community-based food initiatives—remained largely intact, and provided food at a time when the supermarkets were limited in their ability to respond to consumer demand. However, on closer examination of food distribution during flooding in the regional city of Rockhampton and in the State capital, Brisbane, the demarcation of success between “long” and “short” food chains became blurred. Both types of food supply chains shared some key resilience characteristics in responding to crisis but diverged in other important ways. We argue that conceptualizing food chains in terms of key elements of resilience—scale, diversity, flexibility and cohesion—may be more fruitful than the short-long dichotomy alone. This approach is particularly useful when prioritizing food security as the basis for evaluating food system sustainability in a context of predicted increases in extreme weather events and future climate change.  相似文献