The Role of the PFNA Operon of Bifidobacteria in the Recognition of Host’s Immune Signals: Prospects for the Use of the FN3 Protein in the Treatment of COVID-19

Bifidobacteria are some of the major agents that shaped the immune system of many members of the animal kingdom during their evolution. Over recent years, the question of concrete mechanisms underlying the immunomodulatory properties of bifidobacteria has been addressed in both animal and human studies. A possible candidate for this role has been discovered recently. The PFNA cluster, consisting of five core genes, pkb2, fn3, aaa-atp, duf58, tgm, has been found in all gut-dwelling autochthonous bifidobacterial species of humans. The sensory region of the species-specific serine-threonine protein kinase (PKB2), the transmembrane region of the microbial transglutaminase (TGM), and the type-III fibronectin domain-containing protein (FN3) encoded by the I gene imply that the PFNA cluster might be implicated in the interaction between bacteria and the host immune system. Moreover, the FN3 protein encoded by one of the genes making up the PFNA cluster, contains domains and motifs of cytokine receptors capable of selectively binding TNF-α. The PFNA cluster could play an important role for sensing signals of the immune system. Among the practical implications of this finding is the creation of anti-inflammatory drugs aimed at alleviating cytokine storms, one of the dire consequences resulting from SARS-CoV-2 infection.     

Effects of administration of Bifidobacterium animalis subsp. lactis GCL2505 on defecation frequency and bifidobacterial microbiota composition in humans

The aim of this study was to evaluate the changes in endogenous bifidobacteria and administered Bifidobacterium animalis subsp. lactis (B. lactis) GCL2505 (GCL2505) in the intestine after administration of GCL2505 by means of a randomized, placebo-controlled double-blind, cross-over study. An increase in the number of total bifidobacteria (the sum of B. bifidum, B. breve, B. longum subsp. longum, B. adolescentis, B. anglatum, B. catenulatum, B. pseudocatenulatum, B. dentium, B. longum subsp. infantis and B. lactis) in the feces were observed after administration of GCL2505 using species- and subspecies-specific real-time polymerase chain reaction analysis. However, the number of endogenous bifidobacteria species (excluding B. lactis) remained unchanged. B. lactis also became the predominant bifidobacterial species. Taking into account the number of GCL2505 administered, the findings further suggested that GCL2505 proliferated in the intestine. In addition, the defecation frequency increased during GCL2505 administration compared with the placebo. Moreover, a single administration study (n=17) clearly demonstrated that GCL2505 successfully reached the intestine before proliferating at least 10-fold. This is the first report to show an increase in intestinal bifidobacteria, with no changes to the endogenous species, and improvements in constipation following proliferation of administered bifidobacteria.     

分子生物学技术在双歧杆菌检测中的应用

从核酸探针、聚合酶链式反应、分子标记、实时PCR等分子生物学技术在双歧杆菌检测中的应用等方面作以综述，并指出各种检测技术的局限性及应用前景。     

伴大豆球蛋白胃蛋白酶水解肽对双歧杆菌增殖的影响

大豆种子的贮藏蛋白主要由2种球蛋白组成,伴大豆球蛋白(conglycinin)是其中一种,它由3个不同的亚基组成。文中对伴大豆球蛋白进行了分离纯化,并研究了其体外经过胃蛋白酶水解后的肽对双歧杆菌增殖的影响。结果表明,分离纯化的伴大豆球蛋白纯度为90.13％,可供生理功能的研究,经胃蛋白酶水解后的肽能够促进双歧杆菌的增殖,表现出一定的生物活性作用。     

母乳中的低聚半乳糖研究和应用的最新进展

本详述了低聚半乳糖的研究和应用的最新进展,并简述了低聚半乳糖的特性。     

试论人体必需的第八大营养素──益生菌

人体所必需的营养素公认有七种,即蛋白质、脂肪、碳水化合物、水、维生素、矿物质和膳食纤维。本文第一次提出人体必需的第八大营养素──益生菌（Ｐｒｏｂｉｏｔｉｃｓ）,即人体肠道内的有益的正常菌群。这是因为益生菌对人体的生理作用是其它七种营养素所不能取代的。随着年龄的增长、食物结构的变化、环境的污染和抗生素的滥用,人体内的益生菌会逐渐减少或失调,因而造成很多种疾病的发生,经常补充益生菌会对很多种疾病有预防和治疗作用。益生菌的生理作用和营养作用将会越来越受到研究者和消费者的关注。     

双歧杆菌在大豆酸乳中的应用研究

对双歧杆菌菌种发酵大豆酸乳的可行性进行了研究,并对开发大豆酸乳的生产工艺及各种主要影响因素作了进一步探讨。实验结果证明：只要做好菌种的驯化工作和选择合适的工艺技术参数,利用两歧双歧杆菌发酵大豆酸乳是完全可行的。     

Alginate Encapsulated Bifidobacteria Survival in Mayonnaise

Bifidobacterium bifidum and Bifidobacterium infantis were added to mayonnaise as either free cells or encapsulated. The survival of bifidobacteria and their effect on mayonnaise quality were evaluated. The viability of free cells disappeared after 2 wk; however, encapsulated B. bifidum survived well for 12 and B. infantis for 8 wk. Mayonnaise containing encapsulated bifidobacteria had lower total bacterial counts compared to other treatments. Yeast and mold started to appear after 12 wk of storage in mayonnaise containing encapsulated bifidobacteria and after 6 wk with other treatments (control, cells free of bifidobacteria). Mayonnaise containing encapsulated bifidobacteria had higher titratable acidity and lower TBA values than other treatments. Sensory properties of mayonnaise were improved by the addition of encapsulated bifidobacteria.     

Growth and Acid Production by Lactic Acid Bacteria and Bifidobacteria Grown in Skim Milk Containing Honey

ABSTRACT: Twelve percent nonfat dry milk containing 5% (w/w) honey, fructose, or sucrose were pasteurized and inoculated with Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrukeii subsp bulgaricus , or Bifidobacterium bifidum. Inoculated tubes were incubated at 37 °C, 24 h. Samples were collected at 0 and 24 h and examined for (a) viability of bacteria, and (b) levels of fermentation end products (lactic and acetic acids) as measured by HPLC. Honey supported growth of all 4 organisms similar to other sweeteners and was not inhibitory. Lactic acid production was similar for all, except for bifidobacteria and was not influenced by sweetener type. Although lactic acid production was enhanced (p < 0.05) when bifidobacteria were grown in the presence of honey, acetic acid production was not affected. Various oligosaccharides found in honey may be responsible for enhanced lactic acid production by bifidobacteria.