Mechanism of inhibition caused by long-chain fatty acids in anaerobic digestion process

The inhibitory effect of long-chain fatty acids on the anaerobic digestion process was examined in batch experiments using synthetic substrates. The addition of long-chain fatty acids caused the appearance of the appearance of the lag period in the methane production from acetate and in the degradation of both long-chain fatty acids and n-butyrate. Methane production from hydrogen proceeded without lag period although its rate was lowered. Fermentation of glucose was not inhibited. Neutral fat in the whole milk was easily hydrolyzed to long-chain fatty acids, which brought about the inhibition. The addition of calcium chloride reduced the inhibitory effect of long-chain fatty but it did not do so after the culture had been exposed to long-chain fatty acids for more than several hours. The addition of calcium carbonate could not reduce the inhibition because of its insolubility.     

Fractionation of chromosomal proteins of pea seedlings using procedures which avoid denaturation

Chromatin was prepared from the buds and cotyledons of Alaskapea seedlings. The dissociated chromosomal components in thepresence of 2 M NaCl and 5 M urea were completely fractionatedinto DNA and proteins with a Bio-Gel A50 column. The proteinswere recovered by (NH₄)₂SO₄ and further fractionated into histonesand non-histone proteins using a Bio-Rex 70(Na⁺) column. Thedifference in the ratios of histones to non-histone proteinsbefore and after chromatography with the Bio-Rex 70 was lessthan 10%. The histones and non-histone proteins thus preparedshowed typical protein absorption spectra. Polyacrylamide gelelectrophoresis of histones showed that the histone compositionsin buds and cotyledon were similar, but the amount of HI histoneswas a little less in cotyledons than in buds. Unlike histones,non-histone proteins fractionated by SDS-polyacrylamide gelelectrophoresis indicated distinct differences between the twotissues. Buds had more heterogeneous non-histone proteins, atleast 13 polypeptides, than cotyledons did. On the other hand,non-histone proteins of cotyledons showed less heterogeneityand lacked proteins of high molecular weight which were foundin buds. (Received May 6, 1976; )     

Microstructural changes in the basal ganglia in restless legs syndrome and migraine

Sleep and Biological Rhythms -     

Polymorphism of T-cell receptor genes among laboratory and wild mice: Diverse origins of laboratory mice

Southern blots of genomic DNA from 23 strains of laboratory mice and 19 individual wild mice were examined for restriction fragment length polymorphisms in their loci encoding the T-cell receptors (Tcr): the constant regions of the α, β, and γ chains (C _α,C _β, andC _γ) and a variable region family of the β chain (V _β8). Only a few polymorphisms were observed for each locus in the laboratory mice after using three restriction enzymes,Bam HI,Eco RI, andHind III. All the laboratory mice examined fall into one of two types for theC _α,C _β andV _β8 loci and one of three types for theC _γ. These types are found in some of the wild mice studied, indicating that they were already present in the founder mice of laboratory mouse strains. In contrast, theTcr genes are highly polymorphic among wild mice. Analysis of the polymorphisms in these loci suggests that laboratory mice have inherited their genes not only fromMus musculus domesticus, but also from other subspecies, and much more than previously believed from Asian subspecies.     

Structure of human phenylethanolamine n-methyltransferase gene: existence of two types of mRNA with different transcription initiation sites

The chromosomal gene for human phenylethanolamine N-methyltransferase (PNMT; EC 2.1.1.28) was isolated from a human genomic library using a cloned human PNMT cDNA as a probe, and the nucleotide sequence was determined. PNMT is encoded in a single gene which consists of three exons. We observed newly the presence of minor PNMT mRNA (type B) besides the major mRNA (type A) as reported previously (Kaneda et al., J. Biol. Chem. 263, 7672–7677, 1988) by Northern hybridization. Type B mRNA carries an approximately 700 nucleotide-long untranslated region in the 5′ terminus. This suggests that two types of mRNA are produced from a single gene through the use of two alternative promoters. A TATA-like sequence locates 30 base pair upstream from the cap site of type A mRNA. Upstream of the cap site, there are several sequences resembling Spl binding sites and glucocorticoid responsive elements, with the latter also found in the first intron.     

Prosthetic group content and ligand binding properties of a spinach catalase

A recently discovered form of spinach catalase that contains both a novel heme and protoheme as prosthetic groups has been characterized using immunological and spectroscopic techniques. The enzyme appears to be a dimer of identical Mr 60,000 monomers. Extraction of the non-covalently bound prosthetic groups, followed by thin-layer chromatography of the extract, suggested that the novel heme contains four carboxylic acid side-chain groups. The resonance Raman spectrum of the resting enzyme indicates that the protoheme prosthetic group is five-coordinate and high-spin. The enzyme was shown to bind formate, azide and cyanide. Cyanide and azide binding to catalase are biphasic, suggesting the existence of two different binding sites for cyanide and azide in the enzyme. Results obtained from EPR and resonance Raman spectroscopies also support the hypothesis that two different ligand-binding sites are present in the enzyme. Western blots suggest that the Mr 60,000 peptide of the novel heme-containing catalase is similar or identical to that of a previously characterized, exclusively protoheme-containing, tetrameric catalase.     

Changes in whole body concentrations of thyroid hormones and cortisol in metamorphosing conger eel

Summary To clarify the hormonal regulation of metamorphosis of the conger eel (Conger myriaster), changes in whole body concentrations of thyroid hormones, thyroxine (T₄) and triiodothyronine (T₃), and cortisol during metamorphosis were examined, as well as the changes in the histological activity of the thyroid gland. In larvae before metamorphosis, T₄ and T₃ levels were less than 5 and 0.15 ng·g^-1 respectively. Levels of T₄ increased to about 30 ng·g^-1 during early metamorphosis, and decreased subsequently. Levels of T₃ increased gradually in early metamorphosis, and then increased abruptly to about 2.0 ng·g^-1 in late metamorphosis. Before metamorphosis, cortisol levels of the leptocephali less than 11 cm in total length were greater than 200 ng·g^-1. Cortisol levels decreased rapidly in larger premetamorphic leptocephali, and low levels were maintained throughout the metamorphic period. Histological observation revealed an activation of the thyroid gland in early metamorphosis; thyroid follicle epithelial cells became columnar and their nuclei larger. Active uptake of colloid by these cells and intensive vascularization of the gland were also observed. By the end of metamorphosis, follicle epithelial cells became squamous, indicating a low level of glandular activity. These results suggest that thyroid hormone plays an important role in regulation of conger eel metamorphosis.Abbreviations AL anal length - TL total length - T ₃ triiodothyronine - T ₄ thyroxine