水牛αS1-酪蛋白多态性对马苏里拉干酪品质的影响

目的分析水牛α_(S1)-酪蛋白多态性对马苏里拉干酪品质的影响。方法以α_(S1)-酪蛋白AB型、α_(S1)-酪蛋白BB型和混合组水牛乳样为原料分别制成全脂马苏里拉干酪,比较3组水牛乳样和干酪在组成、功能特性和微观结构等方面的差异。结果α_(S1)-酪蛋白AB型水牛乳在脂肪、蛋白质和总固形物含量上显著高于BB型。制成马苏里拉干酪后,AB型干酪的蛋白质含量显著高于BB型和混合组干酪。BB型和AB型干酪在硬度、咀嚼性和胶黏性上显著高于混合组。结论不同基因型α_(S1)-酪蛋白水牛乳的乳成分存在差异,α_(S1)-酪蛋白多态性与水牛乳马苏里拉干酪的组成、质构和融化特性等存在显著关联。     

乌贼墨生物活性研究进展

目前,从海洋生物中寻找活性物质,是研究开发天然药物的一个重要方向。乌贼是丰富易得的海洋生物,而乌贼墨是乌贼加工中的废弃物,它作为一种极具潜力的海洋活性物质,具有止血、抗菌、增强免疫、抗肿瘤、抗氧化等多种生理活性。而乌贼墨多糖就是从乌贼墨中分离出的一种主要活性成分,在抗氧化、抗肿瘤、抗化疗、增强免疫等功能活性方面均表现出了良好的作用效果。通过对乌贼墨中生物活性成分的研究,不仅为乌贼加工废弃物提供了高值化利用途径,也为开发临床医药、保健食品提供了新的资源,对扩大药源及对海洋资源的充分利用都具有深远意义,已受到科研工作者的广泛关注。本文通过综合近年来国内外有关乌贼墨及其活性多糖的研究进展,对它们的理化性质、生物活性和临床应用等方面进行了较为系统的综述,并根据其研究特点和应用前景提出了未来研究的发展方向。     

Genome-wide analysis of runs of homozygosity in Italian Mediterranean buffalo

Runs of homozygosity (ROH) are a powerful tool to explore patterns of genomic inbreeding in animal populations and detect signatures of selection. The present study used ROH analysis to evaluate the genome-wide patterns of homozygosity, inbreeding levels, and distribution of ROH islands using the SNP data sets from 899 Mediterranean buffaloes. A total of 42,433 ROH segments were identified, with an average of 47.20 segments per individual. The ROH comprising mostly shorter segments (1–4 Mb) accounted for approximately 72.29% of all ROH. In contrast, the larger ROH (>8 Mb) class accounted for only 7.97% of all ROH segments. Estimated inbreeding coefficients from ROH (F_ROH) ranged from 0.0201 to 0.0371. Pearson correlations between F_ROH and genomic relationship matrix increased with the increase of ROH length. We identified ROH hotspots in 12 genomic regions, located on chromosomes 1, 2, 3, 5, 17, and 19, harboring a total of 122 genes. Protein-protein interaction (PPI) analysis revealed the clustering of these genes into 7 PPI networks. Many genes located in these regions were associated with different production traits. In addition, 5 ROH islands overlapped with cattle quantitative trait loci that were mainly associated with milk traits. These findings revealed the genome-wide autozygosity patterns and inbreeding levels in Mediterranean buffalo. Our study identified many candidate genes related to production traits that could be used to assist in selective breeding for genetic improvement of buffalo.     

Viability of lactic acid microflora in different types of yoghurt

The suitability of three culture media (Skim milk agar, M17 agar and MRS agar, incubated under aerobic and anaerobic conditions) to obtain total and differential counts of yoghurt bacteria, was assayed. A total of 25 samples of different yoghurt types (set, skimmed set, drinking, and set with “dulce de leche”) obtained with the culture IA, were used. The lactic microflora viability was studied at 6°C and 12°C. Skim milk agar (aerobiosis) was the most useful medium for total and differential counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Cell viability depended on the yoghurt type and the storage temperature. On the basis of a minimum value of 10⁷ CFU g⁻¹, the shelf life of yoghurts at 6°C was longer than 60 days, with the exception of the drinking type (45 days). At 12°C, shelf life was identical for the skimmed drinking yoghurt but lower for the other yoghurt types. Both the storage temperature and the yoghurt type should be taken into account when shelf life is specified on the basis of the lactic microflora content.