Effects of high-pressure processing at low temperature on the molecular structure and surface properties of beta-lactoglobulin

High-pressure processing (HPP) was utilized to induce unfolding of beta-lactoglobulin (beta-LG). beta-Lactoglobulin solutions at concentrations of 0.5 mg/mL, in pH 7.5 phosphate buffer, were pressure treated at 510 MPa for 10 min at either 8 or 24 degrees C. The secondary structure, as determined by circular dichroism (CD), of beta-LG processed at 8 degrees C appeared to be unchanged, whereas beta-LG processed at 24 degrees C lost alpha-helix structure. Tertiary structures for beta-LG, as determined by near-UV CD, intrinsic protein fluorescence spectroscopy, hydrophobic fluorescent probe binding, and thiol group reactivity, were changed following processing at either temperature. The largest changes to tertiary structure were observed for the samples processed at 24 degrees C. Model solutions containing the pressure-treated beta-LG showed significant decreases in surface tension at liquid-air interfaces with values of 54.00 and 51.69 mN/m for the samples treated at 24 and 8 degrees C, respectively. In comparison, the surface tension for model solutions containing the untreated control was 60.60 mN/m. Changes in protein structure during frozen and freeze-dried storage were also monitored, and some renaturation was observed for both storage conditions. Significantly, the sample pressure-treated at 8 degrees C continued to display the lowest surface tension.     

如何解决土地板结

解决土地板结要采取农机和农艺相结合的原则进行综合防治。第一,土地经过多年的开发耕种,土壤有机质已严重不足,单靠化肥或化肥比例过大是地力衰退、土壤板结的主要原因。农作物秸秆是重要的有机肥源,秸秆根茬还田是增肥地力的有效措施之一。秸     

用碱性铁盐和锌盐作为土壤改良剂

在温室栽培莴苣的试验中，比较了施锌和铁碱性盐与施市售螯合物的效果，结果发现碱性盐不但在改善铁和锌营养方面在螯合物同样有效，而且对环境较安全。     

影响猪肉品质的营养因素

影响猪肉品质的因素很多。除猪本身的遗传特性外，还有环境、营养及饲养管理等。实践证明。通过给猪饲料添加不同营养成分及调整饲料营养结构等手段，可改善猪肉品质。本文就利用营养调控来改善猪肉品质作一综述。     

Hematuria associated with cystic hematomas in three neonatal foals

Cystic hematomas were diagnosed in 3 neonatal foals. In all 3 foals, cystic hematomas resulted from umbilical trauma or thrombocytopenia. Findings in these foals suggest that cystic hematoma should be included in the differential diagnosis of hematuria in neonatal foals. Management of cystic hematomas includes both medical and surgical options.     

Ribotyping of Indian Isolates of <Emphasis Type="Italic">Pasteurella multocida</Emphasis> Based on 16S and 23S rRNA Genes

The applicability of ribotyping based on 16S and 23S rRNA was evaluated for molecular epidemiological studies. Forty-eight isolates of Pasteurella multocida isolated from different hosts and geographical locations and one reference isolate were ribotyped. Only four ribotypes were found. All the isolates including reference isolate from wild carnivores had the same ribotype, though they had different serotypes. The isolate from a tiger had one band in addition to the bands present in the major ribotype. The isolates from lions represented two ribotypes; of these ribotypes, one (r2) had an additional band of 3.6 kbp, which was absent in all other ribotypes. The second ribotype (r4) from a lion had one band missing (6 kbp) that was present in the other ribotypes. These isolates were further typed using ERIC-PCR and REP-PCR. With ERIC-PCR and REP-PCR, higher D values of 0.83 and 0.89 were obtained. The current study revealed that ribotyping is not a very efficient typing tool for use in molecular epidemiology for differentiation of isolates.