BIOTIN-ACTIVE COMPOUNDS,THEIR EXISTENCE IN NATURE AND THE BIOTIN REQUIREMENTS OF YEASTS

After a short account of the discovery of biotin and the progress of early biotin research, the natural occurrence of biotin with particular consideration to the raw materials used in the fermentation industry and its products is described. Of the many known biotin derivatives, those appearing in nature and those which can be converted to biotin-active (or inactive) compounds by simple procedures are reported. Ways to by-pass the need for biotin in microbes is discussed. The importance of biotin in yeast production, the biotin requirements of yeast, and the effect of culture conditions on these requirements are reported. The close relationship between the participation of biotinylenzymes and the biotin requirements is noted.     

The impact of parity and duration of biotin supplementation on white line disease lameness in dairy cattle

A field study was conducted to examine effects of oral biotin supplementation for up to 18 mo on risks of lameness in dairy cows. The study included a total of 900 cattle from five dairy farms in Gloucestershire, southwest U.K., in a within-herd randomized control trial. The data from this trial were used in this paper to investigate the impact of parity and duration of supplementation with oral biotin at 20 mg/d on white line disease (WLD) lameness. Analysis of the data indicated that WLD increased with increasing parity independent of biotin supplementation from approximately two cases per 100 cow years in primiparous cows to 15.5 cases per 100 cow years in all multiparous cows, but up to 47.7 cases per 100 cow years for cows in parities > or = 5. Supplementation with biotin reduced WLD lameness by 45% in multiparous cows down to 8.5 cases per 100 cow years, whereas the effect of biotin supplementation in primiparous cows was not significant. Although numerical reductions in WLD lameness were observed for shorter periods of supplementation, a supplementation length of at least 6 mo was required to significantly reduce the risk of WLD lameness in multiparous cows. The effect of biotin supplementation in reducing lameness has potential impact for both animal welfare and farm economics.     

A Multi-Perspective Proximity View on the Dynamic Head Region of the Ribosomal 40S Subunit

A comparison of overlapping proximity captures at the head region of the ribosomal 40S subunit (hr40S) in Saccharomyces cerevisiae from four adjacent perspectives, namely Asc1/RACK1, Rps2/uS5, Rps3/uS3, and Rps20/uS10, corroborates dynamic co-localization of proteins that control activity and fate of both ribosomes and mRNA. Co-locating factors that associate with the hr40S are involved in (i) (de)ubiquitination of ribosomal proteins (Hel2, Bre5-Ubp3), (ii) clamping of inactive ribosomal subunits (Stm1), (iii) mRNA surveillance and vesicular transport (Smy2, Syh1), (iv) degradation of mRNA (endo- and exonucleases Ypl199c and Xrn1, respectively), (v) autophagy (Psp2, Vps30, Ykt6), and (vi) kinase signaling (Ste20). Additionally, they must be harmonized with translation initiation factors (eIF3, cap-binding protein Cdc33, eIF2A) and mRNA-binding/ribosome-charging proteins (Scp160, Sro9). The Rps/uS-BioID perspectives revealed substantial Asc1/RACK1-dependent hr40S configuration indicating a function of the β-propeller in context-specific spatial organization of this microenvironment. Toward resolving context-specific constellations, a Split-TurboID analysis emphasized the ubiquitin-associated factors Def1 and Lsm12 as neighbors of Bre5 at hr40S. These shuttling proteins indicate a common regulatory axis for the fate of polymerizing machineries for the biosynthesis of proteins in the cytoplasm and RNA/DNA in the nucleus.     

有机氮源对谷氨酸棒杆菌发酵L-缬氨酸的影响

以L-缬氨酸生产菌谷氨酸棒杆菌XV0505为供试菌株,研究有机氮源对L-缬氨酸发酵的影响,确定了玉米浆代替豆饼水解液作为有机氮源的发酵工艺,降低了发酵成本;考察不同玉米浆浓度对谷氨酸棒杆菌XV0505发酵生产L-缬氨酸过程中生物量、耗糖速率、L-缬氨酸产量、副产物积累及氨消耗等方面影响,确定了玉米浆的适宜添加浓度;考察了玉米浆与生物素不同配比对L-缬氨酸分批发酵过程的影响,确定了最适生物素添加浓度。与原工艺相比,新工艺的菌体生物量及产酸提高了13.2%和18.5%。     

Effect of Pre‐Filtration on Selective Isolation of Tat Protein by Affinity Membrane Separation: Analysis of Flux,Separation Efficiency,and Processing Time

Abstract

The isolation and purification of Tat protein from bacterial lysate using avidin‐biotin interaction in microfiltration membranes have been reported in the literature. To increase the efficacy of the technique, improvements in flux, Tat separation efficiency, and processing time are essential. In the current research work a pre‐filtration step was introduced to remove unwanted high molecular weight proteins and other impurities from feed prior to affinity membrane separation. Significant enhancement in flux and separation efficiency of Tat was observed. Processing time was also reduced significantly. For example, with UF pretreatment step the total Tat recovery was around four times higher (with processing time 25% lower) than that observed with the untreated feed. The quality of purified Tat was analyzed by SDS‐PAGE, Western Blot, and biotin analysis. Flux behavior in affinity separation was described by model equations.     

Effect of feeding biotin on milk production and hoof health in lactating dairy cows: a quantitative assessment

Objectives of this study were to critically review randomized controlled trials, evaluate the effectiveness of supplementation with biotin on milk yield and composition and hoof health in lactating dairy cows, explore sources of heterogeneity among studies, and evaluate publication bias. Quantitative assessments can increase the statistical power with which we study the effect of treatments, such as biotin, on outcomes. A total of 9 papers, with 6 production and 3 hoof health studies, met the eligibility criteria for meta-analysis. Eight studies evaluated various hoof lesions in biotin-supplemented cows that did not meet the inclusion criteria. Eleven comparisons were made of milk production responses to biotin treatment. Data extracted included the number of cows in control and treatment groups, measures of variance of responses (standard error or standard deviation) and P-values. Other data obtained included the duration of treatment before and after calving, parity, breed of cow, type and dose of biotin, delivery method of supplementation, and types of diets. Biotin increased milk production by 1.29 kg per head per day (95% confidence interval = 0.35 to 2.18 kg) with no evidence of heterogeneity (I² = 0.0%). Treatment did not affect milk fat or protein percentages, and a trend to increase fat and protein yields was observed. Milk production and composition results were not influenced by duration of treatment before calving, parity, or diet type. Assessment of biotin supplementation on hoof health indicated that more studies had improved rather than negative or neutral outcomes. The effect of biotin treatment on milk production was relatively large and the effects on fat and protein yields, although not significant, were consistent in direction and magnitude with the milk response. The hoof health responses to biotin should encourage further studies to more effectively define the nature of these responses using consistent criteria for examination of hoof conditions and lameness.     

Hemicucurbit[n]urils and Their Derivatives – Synthesis and Applications

The first hemicucurbit[n]uril macrocycles were described in 2004, and since then a series of functionalised hemicucurbit[n]uril derivatives have been prepared and studied. The original hemicucurbit[n]urils suffer from sparse solubility, which limits their applications in supramolecular chemistry. Recent progress in the synthesis of a range of derivatives such as the biotin[n]urils, the bambus[n]urils, and the cyclohexylhemicucurbit[n]urils have enabled studies of the supramolecular chemistry of the hemicucurbituril system, both in water and in a range of organic solvents. In contrast to the popular cucurbit[n]uril macrocycles that are state-of-the-art hosts for cations, the hemicucbit[n]urils host anions. Herein we provide a survey of the literature covering the syntheses of the hemicucurbituril derivatives and their supramolecular chemistry.     

基于代谢途径提高红曲黄色素生成及控制橘霉素产生的研究

基于红曲霉菌合成代谢红曲色素和橘霉素的代谢机理,研究了几种化学物质对红曲霉突变菌株合成代谢红曲黄色素和橘霉素的影响。研究结果表明,一定量的生物素、乙酸钙和乙酸锌有利于红曲霉突变菌株合成代谢黄色素。不论辛酸添加量多少和添加时间或早或晚,对于红曲霉突变菌株的生长及其合成代谢黄色素都有明显不利的影响,但是一定量辛酸的添加有利于红色素的合成代谢,在一定程度上也能明显消除橘霉素的合成代谢。     

A Strategy for the Construction of Controlled,Three‐Dimensional,Multilayered, Tissue‐Like Structures

Differentiated cells make up tissues and organs, and communicate within a complex, three dimensional (3D) environment. The spatial arrangement of cellular interactions is difficult to recapitulate in vitro. Here, a simple and rapid method for stepwise formation of 2D multicellular structures through the biotin‐streptavidin (SA) interaction and further construction of controlled, 3D, multilayered, tissue‐like structures by using the stress‐induced rolling membrane (SIRM) technique is reported. The biotinylated cells connect with the SA‐coated adherent cells to form a bilayer. The bilayer of two types of cells on the SIRM is transformed into 3D tubes, in which two types of cells can directly interact and communicate with each other, mimicking the in vivo conditions of tubular structures such as blood vessel. This method has the potential to recapitulate functional tubular structures for tissue engineering.     

SPR技术检测奶粉中生物素

目的利用表面等离子共振(surface plasmon resonance,SPR)技术,建立快速定量测定牛奶中生物素的方法。方法将生物素共价偶联到表面等离子共振芯片CM5表面,并对竞争结合的生物素结合蛋白的结合浓度及芯片的再生条件进行优化,检测芯片的稳定性。在无抗生素牛奶中添加系列质量浓度的生物素,利用免疫竞争抑制原理构建标准曲线,并对市售10个奶粉样品进行检测。结果制备的芯片稳定,50个循环相对标准偏差(relative standarddeviation,RSD)小于10%。日间批内同一样品差异为8.75%,该方法的检测限为0.1μg/100g,回收率为80.4%~91.2%。10个牛奶产品中生物素含量全部在固定的允许范围内。所建立的方法可以在4 h内完成样品的前处理和检测。结论该方法是一种简便、快捷的定量检测方法。