Differentiation between acetate and higher volatile acids in the modeling of the anaerobic biomethanation process

This paper presents a model for the single-stage completely-mixed anaerobic digestion of complex substrates containing no volatile acids. In the model, volatile acids produced by the acidogenic bacteria are no longer considered together. Acetate is assumed to be representative of the substrate and propionate and butyrate act only as inhibitors for the methanogenic bacteria.Nomenclature ···0 represents factors associated with the influent - ···1 represents factors associated with the acidogenic bacteria - ···2 represents factors associated with the methanogenic bacteria - Q hydraulic flow (1/d) - V reactor liquid volume (1) - T temperature of the mixed liquor (° C) - S microorganisms concentration (mg/1) - L volatile solids concentration (mg VS/1) - Lb biodegradable volatile solids concentration (mg VS/1) - VA2 acetate concentration (mg/1) - VA3 volatile acids with 3 to 5 carbon atoms concentration (mg/1) - methane rate production (1 CH₄/1_digester.d) - Km saturation coefficient (mg/l) - Ki inhibition coefficient (mg/l) - specific growth rate (1/d) - maximum specific growth rate (1/d) - b biological decay coefficient (1/d) - Arrhénius coefficient (–) - yield of acidogenic bacteria per mg of biodegradable matter consumed (mg S₁/mg L_b) | (mg S₂/mg VA2) - yield of methanogenic bacteria per mg of VA2 consumed - yield of methane production per mg of S₂ formed (1 CH₄/mg S₂) - proportion of VA2 produced per mg of S₁ biosynthetised - proportion of VA3 produced per mg of S₁ biosynthetised - Y_sp volume of CH₄ produced per g of volatile solids eliminated     

Quantitative changes and ultrastructural alterations of the cornea in response to ultraviolet light II. Effects on amphibia; elucidation of desmosomal structure and basement membrane synthesis

The cornea of the urodele amphibian Triturus c. cristatus was studied ultrastructurally in order to provide the basis for a comparison among corneas throughout the vertebrate phylum. The cornea of this salamander consists of relatively thick epithelium and basement membrane and thin Descemet's membrane, unlike the mammalian corneas. The outermost epithelial cells contain Ruthenium Red stainable extracellular filaments and intracellular vesicles which are thought to play a role in the process of lubricating the corneal surface. Occluding junctions have been observed in the apical region of the superficial epithelial cells and are considered as barriers to the intercellular passage of material. A thin substantia propria (stroma) consists of about 40 collagenous highly organized lamellae. The thicknesses of the basement membrane, Descemet's membrane and the epithelium are believed to represent the primitive situation in the process of corneal evolution.     

Studies on hemoglobin variants in Korean cattle

814 hemoglobin samples from Korean cattle were investigated by starch gel electrophoresis for the detection of hemoglobin variants. A new variant of cattle hemoglobin, called Hb, H, was recognized. It has a slower rate of migration than Hb A.
Hemoglobin types from 814 Korean cattle were as follows: 652 of Hb AA type (80.1 %), 133 of Hb AB (16.4 %), 12 of Hb AC (1.5 %), 9 of Hb BB (1.1 %), 2 of Hb BC (0.2 %), 4 of Hb AH (0.5 %), 1 of Hb CH (0.1 %), 1 of Hb HH (0.1 %). These figures correspond to the frequencies: Hb^A = 0.893, Hb^B = 0.093, Hb^c =0.009, Hb^H = 0.004.
Gene frequencies at the Hb locus in Korean cattle were compared among six population from different provinces. Generally, high frequencies of Hb^A were observed in each province.     

Primary sequence of the beta-chain of Badger haemoglobin.

Badger (Meles meles) haemoglobin was purified by paper electrophoresis and converted into globin. Chain separation was carried out on a CM-cellulose column in the presence of 8 M urea. The beta-chain was aminoethylated, purified by gel filtration and submitted to tryptic digestion. A fingerprint obtained with the enzymic digests showed 17 distinct ninhydrin-positive spots from which 20 pure peptides were isolated by further electrochromatographic separations. These peptides were sequenced using Dansyl-Edman and Ptc-Edman degradation techniques. The presence of amide residues was confirmed after aminopeptidase M hydrolysis. Taking human haemoglobin beta-chain as a model, the covalent structure could be completely resolved without the help of any further overlapping technique. The following substitutions were noted (badger/human, position): Ala/Pro5, Ser/Ala13, Tyr/Phe41, Asp/Glu43, Ser/Ala70, Glu/Asp73, Lys/Ala76, Asn/His77, Lys/Thr87, Lys/Arg104 and Gln/Pro125. A comparison with other haemoglobin beta-chains already sequenced shows a greater similarity with dog haemoglobin, the only example of beta-chain of known structure in the order of Carnivores.     

Semisolid fermentation of ryegrass straw

Candida utilis, Aureobasidium pullulans, and Trichoderma viride were grown on pretreated ryegrass straw. The pretreatment consisted of hydrolysis of straw with 0.5 N H₂SO₄ (water-substrate, 3:1) at 121 C, 100 C, and room temperature and adjustment of the hydrolysate to pH 4.5 to 5.0 with 5 N NH₄OH. The 121 C pretreatment yielded a material containing 30% sugar and 2.3% N. The fermentation was carried on semisolid substrate (moisture level, 75%) in rotating jars for 2 to 3 days at room temperature. The organisms grew rapidly during the period from 18 to 42 h of incubation. During this period the number of microbial cells increased by 20- to 200-fold, and the level of NH₃-N decreased from 1.3 to 0.9%. The fermentation resulted in a fourfold increase in protein, fivefold increase in crude fat, and 40% increase in the digestibility of straw. The best result in terms of increasing protein and digestibility of straw was obtained when C. utilis was grown on straw preheated at 121 C.     

Special problems encountered during the cyanogen bromide cleavage of lobster arginine kinase

During structural analysis of Lobster muscle arginine-kinase, we have isolated a CNBr resulting peptide with a blocked N-terminal residue. This peptide was sequenced after unblocking by mild acid treatment (1 N HCl at 100 degrees C for 10 min). The blocked form is not due to the formation of pyroglutamic acid nor is it due to the formation of diketopiperazine. We have applied the experimental conditions used for CNBr cleavage of lobster arginine-kinase to a synthetic peptide the structure of which is similar to the above CNBr peptide. We bring evidence that during CNBr cleavage partial formylation occurs with a possible cyclization of a 7 membered ring of Gly--Asp...     

Relationship between Raman spectroscopic lines and growth of Rhizobium japonicum

The Raman spectroscopic lines of liquid cultures of Rhizobium japonicum have been compared with electron microscopic examinations and growth measurements of these cells. The results showed that the significant Raman lines are related to the reproduction activities of the procaryotic cells.