The effect of resistant starch (RS) on the bovine rumen microflora and isolation of RS-degrading bacteria

Applied Microbiology and Biotechnology - Resistant starch (RS) in the diet reaches the large intestine without degradation, where it is decomposed by the commensal microbiota. The fermentation of...     

A side reaction in solid phase synthesis. Insertion of glycine residues into peptide chains via Nim----N alpha transfer

In solid-phase peptide synthesis using N alpha-Boc-Nim-tosyl-histidine (Boc-His(Tos)), byproducts having extra Gly residues in the peptide chain were observed at a high rate. When a Boc-amino acid such as Asn was incorporated after assembly of Boc-His(Tos), the Nim-tosyl group was partially or fully cleaved by an activating agent, 1-hydroxybenzotriazole. In the successive coupling reactions, Boc-Gly was incorporated into the free Nim ring as well as the alpha-amino function, and the Nim-Gly was then transferred to the alpha-amino group of Gly of the peptide chain after removal of these Boc groups to give extra Gly residues at the position of Gly. This was observed in only the coupling reaction with Boc-Gly and could be circumvented using a more stable Nim protecting group for His, such as a dinitrophenyl group.     

Fgfbp1 is essential for the cellular survival during zebrafish embryogenesis

Fibroblast growth factor binding protein 1 (FGFBP1) is expressed in various tumors and may serve as a diagnostic marker and/or a therapeutic target. Previous studies suggested FGFBP1 functions as an angiogenic switch molecule by regulating the activity of FGF2, and it was later found to associate with a broad spectrum of FGFs. To study FGFBP1, we used zebrafish, in which the function of extracellular matrix protein can be easily studied in intact tissues or organisms. When Fgfbp1 expression was knocked down, morphants manifested massive cell death and structural abnormalities. Cell death was most prominent in the brain and the neural tube, but not limited to those regions. These findings suggest that the primary function of Fgfbp1 may be to sustain cellular survival throughout embryogenesis. For comparison, the expression of fgf2 was limited to the early stage of embryogenesis and fgf2 morphants showed more severe phenotype, with high morbidity before reaching 14-somites. Taken together, our work reveals the physiologic function of Fgfbp1, and that its function could be exerted in a Fgf2-independent manner.     

Precise localization of the human thyroxine-binding globulin gene to chromosome Xq22.2 by fluorescence in situ hybridization

The human thyroxine-binding globulin (TBG) gene has been localized to X chromosome (Xq22.2) by in situ hybridization using a biotinylated gDNA probe. This is consistent with previous mapping of the TBG gene to chromosome Xq21-q22.     

Dopamine D3 Receptor Mediates Preadolescent Stress-Induced Adult Psychiatric Disorders

Several studies have shown that repeated stressful experiences during childhood increases the likelihood of developing depression- and anxiety-related disorders in adulthood; however, the underlying mechanisms are not well understood. We subjected drd3-EGFP and drd3-null mice to daily, two hour restraint stress episodes over a five day period during preadolescence (postnatal day 35 to 39), followed by social isolation. When these mice reached adulthood (post-natal day > 90), we assessed locomotor behavior in a novel environment, and assessed depression-related behavior in the Porsolt Forced Swim test. We also measured the expression and function of dopamine D3 receptor in limbic brain areas such as hippocampus, nucleus accumbens and amygdala in control and stressed drd3-EGFP mice in adulthood. Adult male mice subjected to restraint stress during preadolescence exhibited both anxiety- and depression-related behaviors; however, adult female mice subjected to preadolescent restraint stress exhibited only depression-related behaviors. The development of preadolescent stress-derived psychiatric disorders was blocked by D3 receptor selective antagonist, SB 277011-A, and absent in D3 receptor null mice. Adult male mice that experienced stress during preadolescence exhibited a loss of D3 receptor expression and function in the amygdala but not in hippocampus or nucleus accumbens. In contrast, adult female mice that experienced preadolescent stress exhibited increased D3 receptor expression in the nucleus accumbens but not in amygdala or hippocampus. Our results suggest that the dopamine D3 receptor is centrally involved in the etiology of adult anxiety- and depression-related behaviors that arise from repeated stressful experiences during childhood.     

Extracellular secretion of levansucrase from Zymomonas mobilis in Escherichia coli

Secretion of levansucrase from Zymomonas mobilis in Escherichiacoli by glycine supplement was investigated. A significant amount of levansucrase (about 25% of total activity) was found in intact whole-cells. Cell fractionation experiments showed that levansucrase was found both in the periplasmic space and in the cytoplasmic fraction of E. coli. None or only trace amounts of levansucrase was detected in the extracellular culture broth at 24 h of cultivation and it accrued with the increasing concentration of glycine in the culture medium and duration of the culture period. Optimal glycine concentration for the maximum secretion of levansucrase was in the range of 0.8-1%, in which approximately 20-50% of levansucrase was released into the extracellular fraction at 24 h of cultivation, although glycine retarded the bacterial growth.