The uptake of D-glucose by glucose-adapted cells of C. thermocellum ATCC-27405 seems to be mediated by an ATP-dependent permease transport system. The existence of this transport system can hypothetically explain the observation that D-glucose is energetically less favorable than cellobiose in sustaining the growth of this microorganism.
When glucose was added to a washed suspension of yeast under aerobic conditions, the heat production curve showed three distinct phases which reflect the metabolic process. The first phase showed a sharp peak which may be attributed to the uptake of glucose the rate of which was proportional to the cell concentration. The results of chemical analyses suggest that the second phase is connected to the metabolism of ethanol, which is followed by the third phase of endogenous metabolism. The second and third phases were nearly absent under anaerobic conditions or when respiration was inhibited. The amount of cellular trehalose, which serves as an energy source, was reflected by the physiological state of the cells, but showed little effect on heat production. The heat produced was proportional to the glucose concentration, depending on the temperature. There were some differences between glucose metabolism and endogenous metabolism in the temperature effect on the rate of heat production. Some correlations between heat production and ATP were observed under anaerobic conditions, but no correlation was observed under aerobic conditions. A comparison was made of enthalpy change with different types of metabolism of yeast. The calorimetric measurements are considered to be a useful approach in studying sugar uptake processes.
Treatment of strains of Escherichia coli with 0.25% phenethyl alcohol resulted in a reversible inhibition of DNA synthesis and cell division. Comparisons of sedimentation behavior for nucleoids isolated prior to and following phenethyl alcohol exposure indicated a dramatic increase in sedimentation velocity, from 3, 220S to 11, 770S. However, following extended phenethyl alcohol exposure, nucleoid sedimentation velocities began to decline spontaneously and to approach that of nucleoids obtained from untreated cultures. Following removal of phenethyl alcohol, DNA synthesis and cell division resumed and nucleoid sedimentation velocities returned to that of controls. Analysis of nucleoids isolated from phenethyl alcohol treated cultures demonstrated the presence of high levels of cosedimenting membrane proteins, indicating that nucleoids were not released from the membrane even though DNA synthesis had terminated. Results are discussed in relation to previously reported phenethyl alcohol-induced perturbations of various cellular processes.
This paper reports the results of a comparison of two aquatic, psychrotrophic bacteria, with regard to growth rate, total cell yield, and total amount of labelled amino acid incorporated into protein, at temperatures within the range 0-30°. Based on growth rate constants, the optimum temperatures for growth, in BOYLEN and BROCK (1) broth, were 25° for isolate F and 30° for isolate T. For both isolates, these temperatures did not give the highest cell yields. Nevertheless, the difference between total cell yield at the optimum growth temperature and the highest total cell yield was not substantial for either isolate. The Arrhenius plots were similar with respect to slope and the absence of any deviation from linearity at the lower temperatures tested. At all of the temperatures examined within the range 0-30°, isolate T incorporated significantly more phenylalanine into protein than did isolate F. This difference in the absolute amount of amino acid incorporated into protein was obvious in all of the growth media tested. The difference could not be attributed to a difference in the protein content of the two isolates. In addition to the incorporation difference between the two isolates, each isolate showed incorporation differences as a function of temperature, and the relationship for each isolate was very different.
The interaction of Pseudomonas pseudomallei with human polymorphonuclear leukocytes (PMNs) has been eamined. Human PMNs ingested P. pseudomallei after incubation for 60min in the presence of normal serum. The bacteria were however relatively resistant to phagocytosis by human PMNs in the absence of serum or in the presence of heat-inactivated serum (56° for 30min). Rapid intracellular killing of P. pseudomallei was observed in the presence of 10% normal human serum; but killing efficiency was reduced in the presence of heat-inactivated serum. Killing in the leukocyte bactericidal assay was shown to be predominantly due to the PMN bactericidal effect; not to the 10% normal serum contained in the incubation mixture. Ingestion of the bacteria was accompanied by a 2-fold stimulation of the hexose monophosphate pathway (HMP). In the absence of phagocytosis, however, the bacteria failed to show a marked enhancement in the HMP-shunt activity. Electron microscopic evidence showed that degranulation and bacterial morphologic changes occurred within 1hr after the organism was ingested. Our data suggest that human PMNs kill P. pseudomallei efficiently after ingestion of the organism in the presence of thermolabile serum opsonins. The occasional chronic nature of the disease caused by P. pseudomallei, therefore, could not be explained simply by the ability of the organism to survive within PMNs.
A menaquinone homologue was isolated from Streptomyces albus IFO 13014. The isolated compound had ultraviolet and infrared absorption spectra very similar to those of menaquinone. The mass spectrum of the compound showed the molecular ion peak at m/z 792, weak fragment ion peaks at m/z 777 (M-15), 583, 515, and 447, and two intense fragment ion peaks at m/z 225 and 187. Fragment ion peaks were not found at m/z 723 (M-69) and 655 (M-69-68) because of the successive loss of isoprene units. The 1H-NMR spectrum exhibited the signals of the following groups: 4×φ-H, δ8.03-7.62; 5×-CH=C-, δ5.04; Q-CH2-, δ3.30 (doublet, J=6.9Hz); Q-CH3, δ2.15; 9×=C-CH2-, δ1.97; =C-CH3 (trans, 1st unit from quinone ring), δ1.76; 4×=C-CH3 (trans, internal units), δ1.57; 3×-CH2-CH2-CH-CH2 and -CH2-CH2-CH-, δ1.25; 5× -C-CH3, δ0.86 (doublet, J=6.3Hz) (φ, benzene ring; Q, quinone ring). The chromenyl acetate was synthesized from the menaquinone and then ozonolyzed. The ozonolysis product represented the mass spectrum of an aldehyde showing ion peaks at m/z 464 (M+), 449 (M-15), 442 (M-42), 407 (M-15-42), 267, and 225. The results indicate that the isolated menaquinone is formulated as 2-methyl-3-II, III, VIII, IX-octahydromultiprenyl9-1, 4-naphthoquinone.
A commercially available pectinase from Aspergillus niger was found to be effective in hydrolyzing to their constituent monosaccharides polysaccharides from Carthamus tinctorius and other flowers, type III pneumococcal polysaccharide, cellobiuronic acid, and other nonpectic saccharides. The enzymes was much less effective in hydrolyzing pneumococcal types I, II, VI, VIII, IX, X, XIII, XXXII polysaccharides and alginic acid.
Since nitrate reductase from a strain of Clostridium perfringens, HM-1, is unique soluble reductase using ferredoxin as electron donor, properties of five strains of this species, HM-1, Am-1, KOA-3, DA-7, and PB6KN5-L9, were investigated using cell extracts for comparison. Though there were two groups of nitrate reductases with different electrophoresis mobilities and isoelectric points, namely 5.5 and 5.7, the molecular weights of HM-1, Am-1, KOA-3, and PB6KN5-L9 were all estimated to be 9×104 by measuring the Rm's at different gel concentrations. In nitrate reduction these enzymes received electrons from ferredoxin the Km of which was 20μM in every case. Antibody prepared against purified nitrate reductase from HM-1 inhibited by more than 80% the nitrate-reducing activity in the extract of each of the five strains. In Ouchterlony's immunodiffusion test, the antibody formed a single precipitation line fusing without spur with the crude extracts from the strains. Such a nitrate reductase as was found in HM-1 seems to be common in species of C. perfringens. Solubilized nitrate reductase from Escherichia coli or Clostridium clostridiiforme extract containing soluble nitrate reductase did not show a cross-reaction, but the enzymatically inactive extracts from HM-1 or DA-7 grown in the presence of tungstate formed a precipitation line fusing with that of the active extracts.
High amounts of β-glucosidase (MW 74, 000) and β-galactosidase (MW 122, 000) were isolated from the periplasmic space of Rhizobium trifolii 4S (infectious strain), compared with the cell homogenate. The characterization of β-glucosidase and β-galactosidase was determined. Both enzymes were inhibited by the addition of Cu2+, Fe2+, Zn2+, Hg2+ and p-chloromercuribenzoic acid. The β-glucosidase exhibited a strong hydrolytic activity on cellobiose, sophorose and laminaribiose to glucose, and the β-galactosidase degraded lactose and O-β-D-galactosyl-1, 3-D-arabinoside to their respective components. Both enzymes hydrolyzed polysaccharide only slightly.
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Edited and published by : Applied Microbiology, Molecular and Cellular Biosciences Research Foundation/Center for Academic Publications Japan Produced and listed by : TERRAPUB, Center for Academic Publications Japan/Shobi Printing Co., Ltd. (-Vol.60,No12), Center for Academic Publications Japan/InternationalAcademic Printing Co., Ltd.(-Vol.54,No1)