Genome relationship betweenPsathyrostachys huashanica andP. fragilis (Poaceae)

Hybrids between the Chinese endemic speciesPsathyrostachys huashanica Keng and the SW. Asian speciesP. fragilis (Boiss.)Nevski (all 2n = 14) developed normally but were completely sterile. Meiotic analyses revealed a high chiasma frequency indicating that the two species as well asP. juncea (Fisch.)Nevski share the same basic genome (called N). The hybrid nature of the plants was established through karyotype analysis and Giemsa C-banding.     

An acetyl esterase of Trichoderma reesei and its role in the hydrolysis of acetyl xylans

Summary An acetyl esterase was purified from Trichoderma reesei by cation and anion exchange chromatography. The enzyme had a molecular weight of 45 000 as determined by SDS-electrophoresis, or 67 000 as determined by gel filtration. In chromatofocusing the enzyme was shown to consist of two isoenzymes with isoelectric points of 6.8 and 6.0. The enzyme showed activity towards naphthyl acetate, triacetin and glucose-and xylose acetates. However, it liberated acetic acid from acetylated xylo-oligomers only to a small extent. The liberation of acetic acid from the oligomeric substrate was enhanced by addition of endoxylanase and -xylosidase.     

A heterozygous defect for structurally altered pro-alpha 2 chain of type I procollagen in a mild variant of osteogenesis imperfecta. The altered structure decreases the thermal stability of procollagen and makes it resistant to procollagen N-proteinase

Cultured skin fibroblasts from a proband with an autosomal dominant variant of osteogenesis inperfecta were found to synthesize approximately equal amounts of normal pro-alpha 2(I) chains of type I procollagen and pro-alpha 2(I) chains which migrated more rapidly when examined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The structural alteration was present in alpha 2(I)-CB4, a cyanogen bromide fragment containing amino acid residues 7-327 of the alpha 2 chain, and it appeared to be a deletion of about 30 amino acids. The pro-alpha 2(I) chains with the apparent deletion associated with normal pro-alpha 1(I) chains synthesized by the same fibroblasts and formed triple-helical type I procollagen. The presence of the altered pro-alpha 2 chains in trimers of procollagen had two consequences in terms of the physical properties of the molecule. One was to decrease the thermal stability of the protein as judged by resistance to proteolysis at 37 degrees C and by the helix to coil transition as assayed by circular dichroism. The second consequence was to make type I procollagen containing the shortened pro-alpha 2(I) chains resistant to digestion by procollagen N-proteinase. The simplest explanation for the data is that the apparent deletion in half the pro-alpha 2(I) chains produced a partial unfolding of the N-terminal region of type I procollagen which prevented processing of the protein by procollagen N-proteinase.     

Expression of genes for plastid membrane proteins in barley under intermittent light conditions

Barley plants grown under intermittent light show a plastid membrane composition intermediate between those of etioplasts and chloroplasts. In particular protochlorophyll reductase disappears from the membranes whereas the 32000 protein, coded for by chloroplast DNA, becomes integrated into the membranes. The light-harvesting chlorophyll a/b protein does not accumulate within the membranes even after 11 d of development, while the corresponding mRNA can already be observed after 4 d and is translated under in vivo conditions.Abbreviations LHCP light-harvesting chlorophyll a/b protein - IL intermittent light - LD light-dark (12-h day) - EGTA ethyleneglycol-bis(oxy-ethylenenitrile)tetraacetic acid     

Kinetics of the appearance of mRNA for light-harvesting chlorophyll a/b protein in polysomes of barley

Polysomes from dark-grown and illuminated barley seedlings were translated in cell-free systems. The translation products reacting with the antibody against the light-harvesting chlorophyll a/b protein (LHCP) were analyzed by polyacrylamide gel electrophoresis. It was found that, in addition to the precursor protein of LHCP, a product was obtained that co-migrated with the mature protein. Furthermore, the results show that the light-induced proly(A)RNA for LHCP is integrated into the polysomal complex without delay, indicating that the integration of LHCP into the membrane is controlled at a higher level of gene expression.     

Growth of sebaceous cells in monolayer culture

Summary Rat preputial cells were grown in an epithelial cell primary monolayer culture system identical to that used for culturing epidermal cells, which were studied for comparison. Despite similar appearance when observed by phase contrast microscopy, other features identified the preputial cells as a unique epithelial cell population. Preputial cells grew as a relatively small number of large colonies, formed domes before confluence, and expressed a specific acinar keratin, K4, which had previously been found in human sebaceous glands. In addition, preputial cells formed fewer cornified envelopes than epidermal cells, too few to discern the reduction of envelope formation by retinoic acid treatment in vitro which was found in epidermal cells. Rat preputial cells in monolayer culture, therefore, are a promising model for studying the effects of hormones on sebaceous cell growth and differentiation.     

Comparison of Neurologic Responses to the Use of Medetomidine as a Sole Agent or Preanesthetic in Laboratory Beagles

Different dose regimens of medetomidine (a potent α2-adrenergic agonist), adding up to a combined dose of 80 µg/kg, were administered to laboratory beagles to determine physiologic responses including neurologic. The study was intended to determine EEG responses where sufficient sedative and analgesic effects are reached with medetomidine and in contrast its effects when used with ketamine or halothane. Cardiopulmonary responses were very similar in each dose regimen, showing the characteristic properties of single doses of 80 µg/kg of medetomidine. Effective sedative and analgesic duration seemed to be a function of when the largest dose was administered. Adequate additional sedative and analgesic could be gained from injections at doses of half of the initial one. The potent sedative and analgesic effects of medetomidine confirmed by neurologic evaluation supports its potential use as a premedication to general anesthesia in dogs. In this study, 2 different doses of medetomidine were also tested as premedication to both ketamine HCl and halothane anesthesia. Neorologic responses were determined at the same time cardiopulmonary parameters, anesthetic quality, and dose requirements were recorded. Medetomidine was found to have favorable qualities in conjunction with these anesthetics. Cardiopulmonary parameters remained satisfactory in both groups as preanesthetic medication prior to halothane, but no additional benefits could be seen from doses of 40 µg/kg medetomidine compared to 20 µg/kg, except a significant 30% reduction in halothane requirement. The positive chronotropic and inotropic properties of ketamine restored the medeto-midine-induced bradycardia and produced a short anesthetic period of 15 to 30 min depending on the dose of medetomidine. The quality of anesthesia was better when 40 µg/kg medetomidine was used, but recorvery was quicker with 20 µg/kg medetomidine. Medetomidine significantly reduced cerebral activity as demonstrated by recordings of total amplitude and frequency evaluation of the EEG with compressed spectral analysis. This analytical method was effective in confirming clinical signs of sedation, analgesia, and anesthesia in canine subjects.