Taurine and β-alanine intraperitoneal injection in lactating mice modifies the growth and behavior of offspring

Taurine, one of the sulfur-containing amino acids, has several functions in vivo. It has been reported that taurine acts on γ-aminobutyric acid receptors as an agonist and to promote inhibitory neurotransmission. Milk, especially colostrum, contains taurine and it is known that milk taurine is essential for the normal development of offspring. β-Alanine is transported via a taurine transporter and a protein-assisted amino acid transporter, the same ones that transport taurine. The present study aimed to investigate whether the growth and behavior of offspring could be altered by modification of the taurine concentration in milk. Pregnant ICR mice were separated into 3 groups: 1) a control group, 2) a taurine group, and 3) a β-alanine group. During the lactation periods, dams were administered, respectively, with 0.9% saline (10?ml/kg, i.p.), taurine dissolved in 0.9% saline (43 mg/10?ml/kg, i.p.), or β-alanine dissolved in 0.9% saline (31 mg/10?ml/kg, i.p.). Interestingly, the taurine concentration in milk was significantly decreased by the administration of β-alanine, but not altered by the taurine treatment. The body weight of offspring was significantly lower in the β-alanine group. β-Alanine treatment caused a significant decline in taurine concentration in the brains of offspring, and it was negatively correlated with total distance traveled in the open field test at postnatal day 15. Thus, decreased taurine concentration in the brain induced hyperactivity in offspring. These results suggested that milk taurine may have important role of regulating the growth and behavior of offspring.     

Isolation and characterization of chromium(VI)-reducing bacteria from tannery effluents and solid wastes

In the present investigation, five novel Cr(VI) reducing bacteria were isolated from tannery effluents and solid wastes and identified as Kosakonia cowanii MKPF2, Klebsiella pneumonia MKPF5, Acinetobacter gerneri MKPF7, Klebsiella variicola MKPF8 and Serratia marcescens MKPF12 by 16S rDNA gene sequence analysis. The maximum tolerance concentration of Cr(VI) as K₂Cr₂O₇ of the bacterial isolates was varying up to 2000 mg/L. Among the investigated bacterial isolates, A. gerneri MKPF7 was best in terms of reduction rate. The optimum temperatures for growth and Cr(VI) reduction by the bacterial isolates were 35 and 40 °C, respectively except A. gerneri MKPF7 which grew and reduced Cr(VI) optimally at 40 °C. The optimum pH for growth and Cr(VI) reduction by K. cowanii MKPF2, A. gerneri MKPF7 and S. marcescens MKPF12 was 7.0 whereas the optimum pH for growth and Cr(VI) reduction by K. pneumoniae MKPF5 and K. variicola MKPF8 were 7.0, 8.0 and 6.0, 7.0, respectively. All the bacterial isolates showed maximum tolerance against Ni²⁺ and Zn²⁺ whereas minimum tolerance was observed against Hg²⁺ and Cd²⁺. The bacteria isolated in the present study thus can be used as eco-friendly biological expedients for the remediation and detoxification of Cr(VI) from the contaminated environments.     

Purification and partial characterization of rat liver bilirubin glucuronoside glucuronosyltransferase.

Bilirubin glucuronoside glucuronosyltransferase (EC 2.4.1.95) converts bilirubin monoglucuronide to bilirubin diglucuronide and is concentrated in plasma membrane-enriched fractions of rat liver homogenates. The enzyme was purified 2,000-fold to homogeneity from rat liver. The pI of the enzyme is 7.9 +/- 0.2. The enzyme has a molecular weight of 160,000 and is an oligomer of 28,000 dalton subunits. Km for purified enzyme was 35 microM and Vmax was 2.2 mumol of bilirubin diglucuronide formed/min/mg of protein. Freshly biosynthesized bilirubin monoglucuronide was injected intravenously into homozygous Gunn rats which had bile duct cannulation. Gunn rats lack UDP-glucuronate glucuronyltransferase activity (EC 2.4.1.17), have normal bilirubin glucuronoside glucuronosyltransferase activity, cannot form bilirubin monoglucuronide in vitro or in vivo, and do not excrete bilirubin glucuronides after intravenous injection of unconjugated bilirubin. Within 1 h, approximately 75% of the injected conjugated bilirubin was recovered in bile, of which 20% consisted of bilirubin diglucuronide. These results indicate that bilirubin glucuronide glucuronosyltransferase catalyzes conversion of bilirubin monoglucuronide to diglucuronide in vivo.     

Nanostructured biocomposite scaffolds based on collagen coelectrospun with nanohydroxyapatite

Nanofibrous biocomposite scaffolds of type I collagen and nanohydroxyapatite (nanoHA) of varying compositions (wt %) were prepared by electrostatic cospinning. The scaffolds were characterized for structure and morphology by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The scaffolds have a porous nanofibrous morphology with random fibers in the range of 500-700 nm diameters, depending on the composition. FT-IR and XRD showed the presence of nanoHA in the fibers. The surface roughness and diameter of the fibers increased with the presence of nanoHA in biocomposite fiber as evident from AFM images. Tensile testing and nanoindendation were used for the mechanical characterization. The pure collagen fibrous matrix (without nanoHA) showed a tensile strength of 1.68 +/- 0.10 MPa and a modulus of 6.21 +/- 0.8 MPa with a strain to failure value of 55 +/- 10%. As the nanoHA content in the randomly oriented collagen nanofibers increased to 10%, the ultimate strength increased to 5 +/- 0.5 MPa and the modulus increased to 230 +/- 30 MPa. The increase in tensile modulus may be attributed to an increase in rigidity over the pure polymer when the hydroxyapatite is added and/or the resulting strong adhesion between the two materials. The vapor phase chemical crosslinking of collagens using glutaraldehyde further increased the mechanical properties as evident from nanoindentation results. A combination of nanofibrous collagen and nanohydroxyapatite that mimics the nanoscale features of the extra cellular matrix could be promising for application as scaffolds for hard tissue regeneration, especially in low or nonload bearing areas.     

Modulation Instability of Bright Envelope Soliton and Rogue Waves in Ultra-relativistic Degenerate Dense Electron–Ion–Positron Plasma

Plasma Physics Reports - Modulation instability, bright envelope soliton, and rogue waves of ion acoustic waves in dense plasma consisting of ultra-relativistic degenerate electrons and positrons,...