Production of Methyl Ketones from Secondary Alcohols by Cell Suspensions of C2 to C4n-Alkane-Grown Bacteria

Nineteen new C₂ to C₄n-alkane-grown cultures were isolated from lake water from Warinanco Park, Linden, N.J., and from lake and soil samples from Bayway Refinery, Linden, N.J. Fifteen known liquid alkane-utilizing cultures were also found to be able to grow on C₂ to C₄n-alkanes. Cell suspensions of these C₂ to C₄n-alkane-grown bacteria oxidized 2-alcohols (2-propanol, 2-butanol, 2-pentanol, and 2-hexanol) to their corresponding methyl ketones. The product methyl ketones accumulated extracellularly. Cells grown on 1-propanol or 2-propanol oxidized both primary and secondary alcohols. In addition, the activity for production of methyl ketones from secondary alcohols was found in cells grown on either alkanes, alcohols, or alkylamines, indicating that the enzyme(s) responsible for this reaction is constitutive. The optimum conditions for in vivo methyl ketone formation from secondary alcohols were compared among selected strains: Brevibacterium sp. strain CRL56, Nocardia paraffinica ATCC 21198, and Pseudomonas fluorescens NRRL B-1244. The rates for the oxidation of secondary alcohols were linear for the first 3 h of incubation. Among secondary alcohols, 2-propanol and 2-butanol were oxidized at the highest rate. A pH around 8.0 to 9.0 was found to be the optimum for acetone or 2-butanone formation from 2-alcohols. The temperature optimum for the production of acetone or 2-butanone from 2-propanol or 2-butanol was rather high at 60°C, indicating that the enzyme involved in the reaction is relatively thermally stable. Metal-chelating agents inhibit the production of methyl ketones, suggesting the involvement of a metal(s) in the oxidation of secondary alcohols. Secondary alcohol dehydrogenase activity was found in the cell-free soluble fraction; this activity requires a cofactor, specifically NAD. Propane monooxygenase activity was also found in the cell-free soluble fraction. It is a nonspecific enzyme catalyzing both terminal and subterminal oxidation of n-alkanes.     

Extracellular glucose-producing exodextranase of the yeast Lipomyces lipofer

A dextran-hydrolysing enzyme from Lipomyces lipofer IGC 4042 was purified from the supernatant of cultures grown on a mineral medium with dextran, by ultrafiltration and gel filtration on Bio Gel A-0.5 m. This preparation gave only one band by disc gel electrophoresis. Glucose was the only product of dextran hydrolysis. Optimum pH and temperature for the activity of the enzyme were pH 4.5–5.0 and 45°C, respectively. The enzyme was most stable over a pH range of 4.5–6.0, and after 2 hours at 50°C maintained over 60% of its original activity. The molecular weight was 29,000 daltons and the isoelectric point was at pH 7. K_m (45°C, pH 5) for dextran T-40 was 1.2×10^–5 M. Glucose inhibited the enzyme competitively with a K_i (45°C, pH 5) of 0.5 mM.     

Standardization of Radiorenography in Dehydrated and Rehydrated Primates Under Laboratory Conditions

Radiorenography with ^99mTo-labelled diethylenctriaminepcntacetic acid ([^99mTc]-DTPA) was performed on chacma baboons (Papio ursinus) and vervet monkeys (Cereopithecus pygerythus) to establish the effects of various states of hydration on the data obtained from the DTPA-renogram. The renogram parameters, which can be related to certain aspects of kidney function, varied significantly with the degree of hydration. It is therefore imperative for clinically directed animal research projects on the urinary system to standardise the experimental procedure for radiorenography. A dehydration of 6 h followed by an hour IU rehydration period using 200 ml of a 0.9% NaCI solution on baboons under thiopentone sodium anaesthetic, was found to be the most suitable procedure for radiorenographic investigations in this primate model.     

Dosage Compensation of Genes on the Left and Right Arms of the X Chromosome of DROSOPHILA PSEUDOOBSCURA and DROSOPHILA WILLISTONI

We have investigated the occurrence of dosage compensation in D. willistoni and D. pseudoobscura, two species whose X chromosome is metacentric with one arm homologous to the X and the other homologous to the left arm of chromosome 3 of D. melanogaster. Crude extracts were assayed for isocitrate dehydrogenase (XR), glucose-6-phosphate dehydrogenase (XL?), 6-phosphogluconate dehydrogenase (XL?), and α-glycerophosphate dehydrogenase (chromosome 2) in D. willistoni, and for esterase-5 (XR), glucose-6-phosphate dehydrogenase (XL?), 6-phosphogluconate dehydrogenase (XL?) and amylase (chromosome 3) in D. pseudoobscura. Our results indicate that a mechanism for dosage compensation is operative in both arms of the X chromosome of these two species.     

Morphological comparison ofSqualus blainvillei andS. megalops in the Eastern Atlantic,with notes on the genus

Morphological comparisons are made from the study of 64 specimens belonging to the following species:Squalus acanihias, S. blainvillei, S. megalops andS. acutirostris. The results suggest conspecificity betweenS. acutipinnis andS. megalops. The differences betweenS. blainvillei andS. megalops in the E-Atlantic are stressed. The Indo-Pacific species calledS. blainvillei by Chen et al. (1979) is regarded in this paper as probably an undescribed species. Some consideration on the status of several nominal species and the species grouping withinSqualus are also made.     

The importance of mast cells for the neutrophil influx in immune complex-induced peritonitis in mice

The role of mast cells in polymorphonuclear leukocyte (PMN) influx in Ag-antibody complex-induced peritonitis was evaluated in mast cell-deficient WBB6F1-W/Wv (W/Wv) mice and their normal littermates, WBB6F1-+/+ (+/+). Peritoneal cell influx was evaluated after i.p. injection of preformed immune complexes. The first significant elevation in the PMN count over PBS-treated controls in +/+ mice was observed 2 h after stimulation. During the period of maximum leukocyte concentrations (6 to 10 h), the increase in total cell count was 5-fold and in PMN 25-fold. In W/Wv mice the PMN influx started 2 h later than in the +/+ mice, and the maximum response (8 to 10 h) was only 50% of that in controls. Reconstitution of mast cells in W/Wv mice for 2 wk or more restored the PMN response to immune complexes. Mast cell release due to AG-antibody complexes was evaluated by measuring fluorescence intensity after berberine sulfate staining for heparin in mast cells from unstimulated as well as stimulated +/+ mice. There was a significant decrease in fluorescence intensity as early as 15 min after stimulation. By 30 min the fluorescence intensity had declined by 65%. This indicates extensive mast cell release that started before PMN mobilization. These experiments demonstrate that mast cells make a significant contribution to immune complex-induced inflammation.     

Postnatal Development of a Granule Cell-Enriched, Neurone-Specific Glycoprotein, gp50, in Normal and Thyroid-Deficient Rats

Glycoprotein gp50 is a neurone-specific, granule cell-enriched glycoprotein that is also a major component of isolated synaptic membranes. Here, we describe the use of a monoclonal antibody, mab SM gp50, to study the postnatal development of gp50 in the brain of normal and thyroid-deficient rats. Radioimmunoassay, enzyme-linked immunosorbent assay, and Western blotting show that gp50 is not detectable in brain until postnatal day 4 (P4) in both forebrain and cerebellum. In forebrain, the rate of increase of gp50 levels is maximal between P12 and P20. It is somewhat later in cerebellum, where peak levels are attained between P30 and P35. Immunocytochemical studies show little detectable gp50-like immunoreactivity before P16, and the staining is still weak, relative to adult tissue, at P25. The intense staining of the granule cell layer characteristic of adult cerebellum predominantly appears after P25. Development of gp50 is severely retarded in the cerebellum of thyroid-deficient rats, particularly during the second and third postnatal weeks. However, by the fourth postnatal week, gp50 levels in normal and hypothyroid animals are comparable. The results indicate that significant alterations in the pattern of gp50 expression continue to occur at a late stage of cerebellar development. In particular, the increase in immunocytochemical staining of the granule cells after P25 is striking in that by this time most major events associated with cerebellar development are essentially complete.