bluuebunny/crossref_metadata_2025 huggingface dataset:
Buoyant density, conversion formulae, and the mole percent guanosine + cytosine content of Desulfovibrio sp.
Authors: Jobson A. , Cook F. D. , Westlake D. W. S.
Published: April 2010

A reevaluation of the original buoyant density conversion formula used to calculate the molar percentage guanosine + cytosine (% G + C) contents of the accepted species of genus Desulfovibrio has been undertaken. It would appear that the formula used gives values 4–5% lower than those obtained using formulae more generally cited in modern literature. Recalculations of % G + C content values for Desulfovibrio DNA are presented using the formulae of three different workers, and are compared with those values originally used in the classification of genus Desulfovibrio.
Extracellular nuclease produced by a marine bacterium. II. Purification and properties of extracellular nuclease from a marine Vibrio sp.
Authors: Maeda M. , Taga N.
Published: April 2010

Extracellular nuclease produced by a marine Vibrio sp., strain No. 2, was purified by salting out with ammonium sulfate and by chromatography on a DEAE-cellulose column and twice on a Sephadex G-200 column. The nuclease was eluted as a single peak in which the deoxyribonuclease (DNase) activity and ribonuclease (RNase) activity appeared together. Polyacrylamide disc gel electrophoresis showed a single band of stained protein which had both DNase and RNase activity. The molecular weight of the enzyme was estimated to be 100 000 daltons. When using partially purified enzyme from the DEAE-cellulose column, the optimum pH for activity was 8.0, and the enzyme was activated strongly by 0.05 M Mg2+ ion and stabilized by 0.01 M Ca2+ ion. These concentrations of Mg2+ and Ca2+ ions are similar to those of the two cations in seawater. Indeed, the enzyme revealed high activity and strong stability when kept in seawater. The presence of particulate matter, such as cellulose powder, chitin powder, Hyflosupercel, Kaolin, and marine mud increased the stability of the enzyme. When the hydrostatic pressure was increased from 1 to 1000 atmospheres, the decrements of the enzyme activity were more pronounced at 30 and 40 °C than at 25 or 50 °C. The enzyme activity was restored after decompression to 1 atm at 30 °C.
An ultrastructural analysis of protoplast–spheroplast induction in Cryptococcus neoformans
Authors: Peterson Ellena M. , Hawley Robert J. , Calderone Richard A.
Published: April 2010

Protoplasts–spheroplasts of a human isolate of Cryptococcus neoformans were prepared using the gut enzyme of Helix pomatia. The induction process, as studied by transmission electron microscopy, occurred in two stages. Early in the induction process, protoplasts–spheroplasts emerged from whole cells through a break in the cell wall – capsule envelope. Later, a gradual dissolution of the entire cell wall occurred releasing the intact protoplast–spheroplast. A comparison of protoplasts–spheroplasts with normal untreated cells revealed that the degree of cellular vacuolation as well as the resolution of cellular organelles was similar.
Effect of magnesium and some nutrients on the growth and nuclease formation of a moderate halophile, Micrococcus varians var. halophilus
Authors: Kamekura Masahiro , Onishi Hiroshi
Published: April 2010

Production of halophilic nuclease by a moderate halophile. Micrococcus varians, ATCC 21971, was maximal at 2.5 to 3.5 M NaCl concentration in a complex medium (CM) composed of 1% casamino acids, 1% yeast extract, and NaCl. The addition of 81 mM MgSO4 to CM inhibited nuclease production in spite of good growth. Microscopic observation showed that this inhibition was accompanied by complete clumping of the cells. The Sehgal and Gibbons complex medium (SGC) which contained 0.75% vitamin-free casamino acids, 1% yeast extract, and NaCl, however, supported good production of the nuclease in spite of the presence of 81 mM MgSO4. It seemed that both magnesium sulfate and some substances present in CM might be responsible for this inhibition and clumping.A synthetic medium optimal for enzyme production was developed consisting of 16 amino acids, 4 vitamins, 0.73 mM KH2PO4, 2.7 mM KCl, 20 mM MgSO4, and 2.5 M NaCl. The organism required biotin as an essential growth factor, and thiamine, riboflavin, and choline as stimulating factors. Omission of isoleucine from the medium reduced markedly the growth rate. Glutamic acid, proline, and arginine were consumed completely during cultivation in the synthetic medium.
Adsorption of Pseudomonas pseudomallei cytophilic antibodies onto rabbit alveolar macrophages
Authors: Kishimoto Richard A. , Eveland Warren C.
Published: April 2010

Cytophilic antibody has been demonstrated in sera from rabbits immunized with Pseudomonas pseudomallei. This antibody passively adsorbed onto normal rabbit alveolar macrophages rendered the macrophages agglutinable by P. pseudomallei antigens and capable of displaying 'rosette' formation with polysaccharide-sensitized erythrocytes.
Stability of mRNA from the Clostridium sporogenes phage F 1
Authors: Taylor Diane E. , Guha Arabinda
Published: April 2010

Polyacrylamide gel electrophoresis was used to study the decay of individual species of mRNA in F 1, a bacteriophage specific for the obligate anaerobie Clostridium sporogenes. Immediate early mRNA species had a half-life of 3.5 min, while delayed early and late mRNA had a half-life of between 6 and 8 min.
A comparison of the prophylactic and therapeutic effects of poly I:C and endotoxin in mice infected with Mengo virus
Authors: Campbell J. B. , White Sandra L.
Published: April 2010

We have compared the protective effect in AKR mice of poly I:C and bacterial endotoxins against lethal doses of Mengo virus. Administered intravenously or intraperitoneally, both interferon inducers protected mice to about the same extent from virus challenges of 2–3 LD50's. Endotoxin, however, was unable to protect the mice effectively against higher challenge doses of virus. Evidence is presented that the level of protection afforded by both inducers is related to the level of circulating interferon produced. We have also shown that a single intravenous dose of poly I:C results in the appearance of two distinct bursts of interferon activity, with maxima at about 2 h and 9 h post injection. Endotoxin, on the other hand, produced only one peak of activity, at 2 h post injection.
Antibacterial activity of marine violet-pigmented Alteromonas with special reference to the production of brominated compounds
Authors: Gauthier M. J. , Flatau G. N.
Published: April 2010

The synthesis of several types of antibiotics was investigated in four strains of violet-pigmented bacteria belonging to the species Alteromonas luteo-violaceus.Two of the strains simultaneously produce an antibiotic polyanionic polysaccharide, weakly bound to the cells and diffusing throughout the medium, and two intracellular brominated bactericidal substances. The third strain only synthesizes the polyanionic antibiotic. The fourth one is totally inactive.The macromolecular antibiotic, probably responsible for the autointoxication of the bacteria in their cultures, acts at the respiratory level; it induces an increase of oxygen uptake and the production of peroxides by test bacteria. Thus, its activity is inhibited by catalase and peroxidase.
The isolation of an infectious A protein – RNA complex from coliphage R17
Authors: Reynolds Shirley , Paranchych William
Published: April 2010

The coprecipitate of A protein and RNA which results from acetic acid treatment of bacteriophage R17 has been shown to form two bands after equilibrium density gradient centrifugation in Cs2SO4. The band of higher density, whose position coincides with that of phage RNA prepared by phenolisation possesses neither A protein nor infectivity while the band of lower density which contains both RNA and A protein is infectious for intact E. coli cells. The nature of the bonding between the A protein and the RNA was also investigated.
Potash guar gum—a source of halophilic bacteria
Authors: Robbins J. W. , Ingledew W. M.
Published: April 2010

Moderate and extreme halophilic microorganisms have been isolated from guar gum solutions dissolved in potash brine for use in sylvite froth flotation. Tentative identifications have been made of Vibrio, Halobacterium, and Halococcus species. Reinoculation of these isolates into guar gum solutions has shown that they are not carbohydrate-utilizing strains, but instead metabolize the contaminating proteins present in guar.
In situ morphologies of deep-sea and sediment bacteria
Authors: Carlucci A. F. , Shimp Susan L. , Jumars Peter A. , Paerl Hans W.
Published: April 2010

Deep-sea and sediment bacteria at the bottom of an approximately 1200-m water column were sampled by means of pressure vessels attached to a remote underwater manipulator. Cells were immediately fixed in situ with glutaraldehyde, and after processing in the laboratory their morphologies were observed with the scanning electron microscope. Most bacteria were coccoid or rod-lide and less than 0.4 μm in diameter or width. Few filamentous bacteria were observed. Bacteria were in aggregates or free-living. It is concluded that morphologies of deep-sea bacteria collected and fixed at the hydrostatic pressure of their environment are, in general, similar to the observed morphologies of deep-sea bacteria determined at 1 atm pressure after collection and decompression during ascent through the water column.
Sulfur amino acid auxotrophy in Micrococcus species isolated from human skin
Authors: Farrior Julian W. , Kloos Wesley E.
Published: April 2010

Since methionine and (or) cysteine are required by a large percentage of natural auxotrophic Micrococcus strains isolated from human skin, investigations were directed to determine the specific enzymes affected in sulfur amino acid biosynthesis. Known intermediates in the interrelated cysteine and methionine biosynthetic pathways were tested as growth stimulants. Based on these growth studies, sulfur amino acid auxotrophs were grouped into three cysteine classes and five methionine classes. Selected auxotrophs of M. luteus had deficiencies in ATP sulfurylase (EC 2.7.7.4) and adenosine-5-sulfatophosphate (APS) kinase (EC 2.7.1.25), sulfite reductase (EC 1.8.1.2), serine transacetylase (EC 2.3.1.30), or β-cystathionase (EC 4.4.1.8)activity; auxotrophs of M. lylae had deficiencies in sulfite reductase and serine transacetylase,β-cystathionase, or N5,N10-methyltetrahydrofolate reductase (EC 1.1.1.68) activity; all auxotrophs of M. seden-tarius tested had deficiencies in N5,N10-methyltetrahydrofolate reductase activity; auxotrophs of M. nishinomiyaensis had deficiencies in adenosine-3-phosphate-5-sulfatophosphate (PAPS) reductase, sulfite reductase, serine transacetylase, or N5,N10-methyltetrahydrorblate reductase activity; auxotrophs of M. varians had deficiencies in APS kinase, PAPS reductase, sulfite reductase, homoserine O-transsuccinylase,β-cystathionase, or N5,N10-methyltetrahydrofolate reductase activity; auxotrophs of M. kristinae had deficiencies in serine transacetylase or cystathionines-γ-synthase (EC 4.2.99.9) activity; auxotrophs of M. roseus had deficiencies in PAPS reductase, sulfite reductase, or serine transacetylase activity. Results of studies with various mutagens suggested that sulfur amino acid auxotrophy was primarily the result of a single base substitution in usually one or two of the genes controlling biosynthesis. A preliminary study of the amino acid composition of sweat suggested that this important source of nutrients does not contain adequate amounts of cysteine for the growth of cysteine auxotrophs but contains methionine that may be utilized in place of cysteine.
Comparative zone electrophoresis of catalase of Staphylococcus species isolated from mammalian skin
Authors: Zimmerman Raymond J.
Published: April 2010

Vertical polyacrylamide slab gel electrophoresis was conducted for the catalase enzymes of representative strains of 18 proposed species and subspecies of the genus Staphylococcus. The catalase bands which resulted were predominantly monomorphic within each of the species and differences in catalase mobilities were observed between many of the species. The electrophoretic mobilities of the catalases were supportive to the scheme of classification used. Many strains of certain species demonstrated multiple catalase bands which are suggestive of multimolecular forms of the enzyme. Horizontal starch gel electrophoresis of representative strains of S. capitis produced catalase bands with relative mobilities that were different from those obtained with polyacrylamide electrophoresis, presumably due to a difference in molecular sieving between the gels.
Induction of staphylococcal β-lactamase in response to low concentrations of methicillin under simulated diving environments
Authors: Wild James R.
Published: April 2010

The influence of simulated diving environments on the antimicrobial activity of a variety of penicillin and cephalosporin congeners was studied in Staphylococcus aureus. Pressure reduced bacteriostatic action provided the antibiotic was susceptible to β-lactamase hydrolysis and the bacterium was inducible for penicillinase. Ethidium bromide curing of the penicillinase plasmid of an inducible strain eliminated the hyperbaric effect. The minimal inhibitory concentration of benzylpenicillin increased about threefold with increasing hyperbaric pressure from 17 to 136 atm. Additional pressurization to 204 atm did not change antibiotic efficacy further. The efficacy of benzylpenicillin was reduced by 68 atm of hyperbaric helium, nitrogen, or a mixture of neon and helium, but was slightly increased by 68 atm of argon, removal of the gas phase, or 68 atm of hydrostatic pressure. Hyperbaric helium had no effect on β-lactamase activity in vitro. An effect was demonstrated upon induction by suboptimal concentrations of methicillin. The concentration of methicillin required for the induction of half-maximal levels of penicillinase in late log cultures of S. aureus was reduced from 0.15 μg/ml at 1 atm to 0.06 μg/ml at 68 atm. The basis of increased resistance to antibiotics exhibited by S. aureus in hyperbaric environments appears to be enhanced efficiency of penicillinase induction.
Preparation of gonococcal antigens by zeolite disruption
Authors: Wallace R. , Ashton F. E. , Ryan A. , Diena B. B. , Vijay H. M.
Published: April 2010

Neisseria gonorrhoeae cells are effectively disrupted with a synthetic zeolite, type 4A. The soluble material released from gonococci contains antigen(s) which are involved in the immune response to gonorrhea in experimentally infected chimpanzees and are common to different gonococcal strains.
β-Glucosidase: microbial production and effect on enzymatic hydrolysis of cellulose
Authors: Sternberg D. , Vuayakumar P. , Reese E. T.
Published: April 2010

The enzymatic conversion of cellulose is catalyzed by a multiple enzyme system. The Trichoderma enzyme system has been studied extensively and has insufficient β-glucosidase (EC 3.2.1.21) activity for the practical saccharification of cellulose. The black aspergilli (A. niger and A. phoenicis) were superior producers of β-glucosidase and a method for production of this enzyme in liquid culture is presented. When Trichoderma cellulase preparations are supplemented with β-glucosidase from Aspergillus during practical saccharifications, glucose is the predominant product and the rate of saccharification is significantly increased. The stimulatory effect of β-glucosidase appears to be due to the removal of inhibitory levels of cellobiose.
Etude des activités NADH et NADPH-ferrédoxine oxydoréductasiques chez Clostridium acetobutylicum
Authors: Petitdemange H. , Cherrier C. , Bengone J. M. , Gay R.
Published: April 2010

The NADH and NADPH-ferredoxin oxidoreductase have been studied in Clostridium acetobutylicum. Acetyl-CoA is an obligatory activator of NADH-ferredoxin reductase activity and NADH a competitive inhibitor of ferredoxin-NAD+ reductase activity. These regulations are the same when C. acetobutylicum moves from 'butylic-type metabolism' to 'butyric-type metabolism'; this demonstrates that NADH-ferredoxin oxidoreductase can. through its reversible action, meet the very different cell needs imposed by these two types of culture. The physiological function of the clostridial NADPH-ferredoxin oxidoreductase was anabolic as it has been with other Clostridia.
Effect of detergents and chemicals on purified vaccinia virus: analysis by SDS polyacrylamide gel electrophoresis and electron microscopy
Authors: Boisvert J. , Yamamoto T.
Published: April 2010

Vaccinia virus particles were dissociated into their constituent polypeptides and analysed by sodium dodecyl sulfate (SDS) gel electrophoresis. Thirty-three distinct polypeptide bands were identified and their molecular weights ranged between 11 000 and 150 000 daltons.Specific staining of gels containing polypeptides of dissociated virions revealed the presence of eight glycopeptides. No lipopeptides were detected.Analysis of chemical extracts (urea, guanidine hydrochloride, and alkali treatment) of the virus by SDS gel electrophoresis indicated that a total of 10 to 14 different polypeptides ranging in molecular weights from 11 000 to 70 000 daltons were solubilized.Analysis of detergent extracts and of the remains of extracted viral particles has shown that the detergent Nonidet P-40 (NP-40) solubilized a total of 11 polypeptides of which 6 were glycopeptides. The other detergents sodium deoxycholate (SDC) and cetyl trimethyl ammonium bromide (CTAB) were not as selective, both solubilizing more than 25 of the polypeptides composing the virus. Gel electrophoresis results also indicated that most of the small molecular weight (11 000–70 000 daltons) polypeptides were readily solubilized by NP-40, SDC, and CTAB, while those with molecular weights of 70 000 daltons and higher were not well solubilized.The effects of detergents were also analysed by electron microscopy. Evidence was obtained for subpopulations of viral particles having different susceptibility to detergent extraction.
Small-scale trial of live-attenuated influenza vaccine (A/Hong Kong/68)
Authors: West R. , Stewart J. A. , White F. M. M. , McDonald J. C. , Boudreault A. , Pavilanis V.
Published: April 2010

Seventy-one men who were given live-attenuated A/Hong Kong/68 (H3N2) influenza vaccine during November 1973, and 34 men given placebo were examined for changes in antibody level. Overall, 12 of the 71 men (17%) given the vaccine showed a fourfold rise in haemagglutination-inhibition (HI) antibody titre after 14 days. No such rises were seen in the 34 men given placebo. However, 10 of the men showing a fourfold rise were from 19 who had no detectable HI antibody to this virus before vaccination, representing a conversion rate of 53%. The other two had a HI titre of 1/10 before vaccination. The absence of antibody response, at 14 days, in those with an HI titre of 1/20 or greater may indicate that this represents a protective level against infection. However, the vaccine virus was probably overattenuated and may have constituted a weaker challenge than might occur with a wild strain.No influenza virus was isolated from either group in the week after vaccination and no evidence of transmission to the placebo group was seen.Mild symptoms, chills, muscle pain, and stiffness were more frequently seen in the 12 persons showing a fourfold rise in antibody than in the rest of the volunteers.
Glutamate uptake in Thiobacillus novellus
Authors: Hoban Daryl J. , Lyric Ronald M.
Published: April 2010

Properties of the glutamate uptake system of Thiobacillus novellus were investigated using intact cells. Two kinetically distinguishable components were found and designated as the high-affinity (HA) component with an apparent Km of 33 μM, and the low-affinity (LA) component with a Km of 18 mM. Glutamate accumulation was temperature-sensitive and could be inhibited by the addition of a wide range of inhibitors including cyanide, dinitrophenol (DNP), iodoacetate, mercuric chloride, sodium azide, carbonyl cyanide m-chlorophenyl hydrazone (CCCP), and dicyclohexylcarbodiimide (DCCD). The complex kinetics of the uptake process may be due to the rapid incorporation of added glutamate into a small peptide. This soluble peptide was formed rapidly after glutamate addition, and accumulated in whole cells.
Interactions of Phytophthora cinnamomi and Trichoderma spp. in relation to propagule production in soil cultures at 26 °C
Authors: Kelley Walter D.
Published: April 2010

Effects of Trichoderma harzianum and T. polysporum on chlamydospore production by two isolates of Phytophthora cinnamomi were determined over a 21-day period in nonsterile, sterilized, and sterilized amended soil. Trichoderma was either coinoculated with P. cinnamomi or added to the cultures on day 3 of the incubation period. In nonsterile soil, conversion of mycelial fragments in the P. cinnamomi inoculum to chlamydospores resulted in an initial slight increase in chlamydospore numbers. In cultures where either of the Trichoderma isolates was added on day 3, a significant reduction in chlamydospore numbers was observed on day 4; however, neither of the Trichoderma isolates at either inoculation time significantly affected chlamydospore numbers by day 21. Results from studies with sterilized amended soil indicated that a reduction in P. cinnamomi chlamydospore numbers by either of the Trichoderma isolates was dependent upon availability of simple carbohydrates. In sterilized nonamended soil, the number of chlamydospores was increased in cultures containing either Trichoderma isolate; in sterilized amended soil chlamydospore numbers were initially reduced, followed by a general increase as the nutrients were depleted. Neither of the Trichoderma isolates exhibited significant antagonistic qualities toward P. cinnamomi.
Nitrate reduction and nitrogenase activity in Spirillum lipoferum
Authors: Neyra Carlos A. , Berkum Peter Van
Published: April 2010

Nitrate and nitrite reduction under aerobic, microaerophillic, and anaerobic conditions was demonstrated in Spirillum lipoferum (ATCC 29145). Nitrite did not accumulate during assimilatory nitrate reduction in air. The nitrite produced during dissimilatory nitrate reduction accumulated in the medium but not in the cells. On exposure of the bacteria to nitrate and anaerobiosis, a low initial rate (lag) was followed by accelerated rates of nitrite accumulation. A 3-h anaerobic pretreatment, in the absence of nitrate, did not avoid the lag phase. No nitrate reductase activity (NRA) developed in the presence of chloramphenicol. The data suggest that induction of anaerobic NRA in S. lipoferum required nitrate and protein synthesis.Anaerobic N2ase activity by S. lipoferum was greatly stimulated in the presence of nitrate. The time course of nitrate reduction was coincidental with the pattern of nitrate-stimulated N2ase activity indicating that a relationship exists between these two processes.
The effect of hyperimmunization with Neisseria gonorrhoeae on the presence of gonococcal antibody in serum, tissues, and secretions of the rabbit
Authors: Ashton F. E. , Collins F. , Wallace R. , Ryan A. , Diena B. B. , Lavergne G.
Published: April 2010

Antibody responses in sera, tissues, and secretions of the urogenital tract and lower respiratory tract of rabbits hyperimmunized with Neisseria gonorrhoeae were examined. Antibody was detected by passive hemagglutination, whole-cell agglutination, bentonite flocculation, and in some cases immunodiffusion-in-gel. Immunization of rabbits either intravenously or intramuscularly resulted in the presence of gonococcal antibodies in the sera, spleens, and tissues of the urogenital tract (vagina, cervix, uterus, and fallopian tubes). Gonococcal antibody was also found in secretions bathing the mucosa of the urogenital tract and lower respiratory tract. Antibodies were not detected in sera, tissues, and secretions of non-immunized rabbits.The spleen was shown to synthesize gonococcal antibody in vitro in response to hyperimmunization. Tissues of the urogenital tract did not appear to synthesize gonococcal antibody thus suggesting that antibodies present in secretions of the urogenital tract were derived mainly from serum.
Studies on some characteristics of hydrogen production by cell-free extracts of rumen anaerobic bacteria
Authors: Joyner A. E. , Winter W. T. , Godbout D. M.
Published: April 2010

Hydrogen production was studied in the following rumen anaerobes: Bacteroides clostridiiformis, Butyrivibrio fibrisolvens, Eubacterium limosum, Fasobacterium necrophormn, Megasphaera elsdenii, Ruminococcus albus, and Ruminococcus flavefaciens. Clostridium pasteurianum and Escherichia coli were included for comparative purposes. Hydrogen production from dithionite, dithionite-reduced methyl viologen, pyruvate, and formate was determined. All species tested produced hydrogen from dithionite-reduced methyl viologen, but only C. pasteurianum, B. clostridiiformis, E. limosum, and M. elsdenii produced hydrogen from dithionite. All species except E. coli produced hydrogen from pyruvate, but activity was low or absent in extracts of E. limosum, F. necrophorum, R. albus, and R. flavefaciens unless methyl viologen was added. Hydrogen was produced from formate only by E. coli, B. clostridiiformis, E. limosum, F. necrophorum, and R. flavefaciens. Extracts were subjected to ultracentrifugation in an effort to determine the solubility of hydrogenase. The hydrogenase of all species except E. coli appeared to be soluble, although variable amounts of hydrogenase activity were detected in the pellet. Treatment of extracts of the rumen microbial species with DEAE-cellulose resulted in loss of hydrogen production from pyruvate. Activity was restored by the addition of methyl viologen. It is concluded that hydrogen production in these rumen microorganisms is similar to that in the saccharolytic clostridia.
A positive difference in nature of envelopes of thymus- and uterus-derived leukemia viruses of AKR mice
Authors: Watanabe Takashi , Nakakuki Kazuya
Published: April 2010

Thymus-derived leukemia vims of AKR/J mice was inactivated by anti-theta antiserum. But it was not inactivated by the antiserum which had been absorbed with intact thymus cells of AKR/J or RF/J mice, and by anti-uterus-derived leukemia virus antiserum. In contrast, uterus-derived leukemia virus of the strain was not inactivated by anti-theta antiserum, but was neutralized by anti-uterus-derived leukemia virus antiserum.The results suggest the possibility that some constituents of the envelope of thymus-derived leukemia virus are derived from the plasma membrane of thymus cells of AKR mice at the time of budding and that such constituents are not associated with the envelope of uterus-derived leukemia virus.
The excretion of enterotoxin B from nongrowing cells of Staphylococcus aureus 4916
Authors: Miller Richard D. , Fung Daniel Y. C.
Published: April 2010

The physiological conditions for the excretion of staphylococcal enterotoxin B (SEB) by nongrowing cells have been determined. In general, SEB excretion appears to be best when amino acids serve as sources of carbon, nitrogen, and energy. Little toxin was produced in a nitrogen-free medium with glucose as the sole carbon source. Inhibitor studies have shown that most of the toxin excreted by nongrowing cells was the result of de novo protein synthesis. Optimum toxin excretion was also obtained under conditions of aeration, and at or near optimum growth temperature, those conditions at which the cells are metabolically and biosynthetically most active. Levels of cell-associated SEB decreased during toxin excretion. However, these levels of toxin could not account for the high levels of toxin released during excretion. Glucose and several other rapidly fermentable carbohydrates inhibited toxin excretion by as much as 80% under conditions of uncontrolled decrease in pH; however, when the pH was kept at either 6.2 or 7.5 a stimulation of toxin excretion was observed. Protoplast studies have suggested that SEB production does not take place in the absence of an intact cell wall.
Sterol content and polyene antibiotic resistance in isolates of Candida krusei, Candida parakrusei, and Candida tropicalis
Authors: Safe L. M. , Safe S. H. , Subden R. E. , Morris D. C.
Published: April 2010

Three isolates, one from each species of Candida krusei, C. parakrusei, and C. tropicalis, obtained from infected patients, were more tolerant of significantly higher concentrations of polyene antibiotics than the corresponding reference wild types. The resistant strains isolated had the same sterols as their wild-type counterparts but in lower concentrations.
Methylamine dehydrogenase from the obligate methylotroph Methylomonas methylovora
Authors: Mehta R. J.
Published: April 2010

An obligate methyltroph Methylomonas methylovora oxidized methylamine, formaldehyde, and formate. Enzymes oxidizing these substrates were detected in a cell-free system. Phenazine methosulfate-linked methylamine dehydrogenese was purified 21-fold. The enzyme had optimum activity at pH 7.5 and was stable at 60 °C for 5 min. The enzyme activity was inhibited by parachloromercuric benzoate, isonicotinic acid hydrazide, mercuric chloride, and sodium borate.
Relationship of cytochrome content to the sensitivity of bacteria to NaCl on freezing and thawing
Authors: Lee Sai K. , Calcott Peter H. , MacLeod Robert A.
Published: April 2010

Eight species of bacteria representing rod, coccus, gram-positive, and gram-negative forms were tested for their sensitivity to sodium chloride during freezing and thawing. Six of the eight species tested were salt-sensitive, though to different degrees, while Lactobacillus casei and Streptococcus faecalis were resistant. Escherichia coli grown anaerobically exhibited only 38% of the salt sensitivity of aerobically grown cells. Analysis of cytochrome pigments in the organisms revealed that the six sensitive organisms all contained these pigments but in varying amounts, while the two resistant ones were devoid of them. Anaerobically grown E. coli contained 50% of the cytochromes of aerobically grown cells. A relationship between cytochrome content of the organisms and salt sensitivity during freezing and thawing was demonstrated with a correlation coefficient of 0.76 (P < 0.05); the higher the cytochrome content, the more salt-sensitive the organism. This indicated that 58% of the salt sensitivity was due to the cytochrome content.Using a model organism, E. coli, the effect of salt during freezing and thawing on the respiratory activity was examined. Freezing and thawing in water or saline decreased the respiration by whole cells of substrates expected to be NAD-linked while NADH-stimulated respiration was increased. In cell-free extracts derived from unfrozen cells or those frozen and thawed in water or saline, the respiration of ascorbate plus N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) was constant. The respiration of NADH, succinate, and lactate in cell-free extracts derived from cells frozen and thawed in saline was reduced compared with those extracts derived from unfrozen cells or cells frozen and thawed in water. Studies with E. coli showed that the decreased respiratory activity caused by disruptions in the electron-transport chain could not account for the salt sensitivity on freezing and thawing. More likely, salt sensitivity is related to the presence of bonds between cytochromes and other membrane components which are disrupted by sodium chloride on freezing and thawing. This would then result in loss of membrane integrity and function.
Relation of colonial morphologies in soft agar to morphological and biological properties of the K-9 strain of Klebsiella pneumoniae and its variants
Authors: Takahashi Masami , Yoshida Kosaku , Clemente C. L. San
Published: April 2010

During repeated subcultures of strain K-9 of Klebsiella pneumoniae, three variants, A, B, and C, were obtained showing different colonial morphologies in soft agar. The parent strain K-9 produced colonies that were large, smooth, and globular; variant A, wedged balloon forms somewhat elongate; variant B, rain-drop-like with some streaming; and variante, small compact rough globules. These colonial forms in soft agar medium correlated well with the size of capsule determined by cell volume index and light microscopy. Organisms exhibiting large globular colonies did possess extra large capsules while strains producing compact-type colonies in soft agar were lacking capsules. Capsular size of the strains correlated well with mouse virulence, but most biochemical properties, including the amount of endotoxic substance, were the same in all strains.
The fine structure of Entomophthora apiculata and its penetration of Trichoplusia ni
Authors: Lambiase James T. , Yendol William G.
Published: April 2010

The fine structure of conidia and immature resting spores of the entomogenous fungus Entomophthora apiculata is described. The two cell types contain comparable organelles and quantities of lipid, and possess a similar cell wall structure. The large quantity of stored lipid and numerous mitochondria in each cell type indicate a capacity for great metabolic activity. Numerous dense, microbody-like organelles were observed in conidia and resting spores, and their possible functions are discussed.Third instar larvae of the cabbage looper Trichoplusia ni were exposed to conidia of E. apiculata. Fungal germ tube formation and penetration of the host integument were observed. The germ tubes did not form appressoria and appeared to penetrate the epicuticle by enzymatic and physical means. After penetration of the epicuticle the germ tube often bifurcates, and expands as two or more digit-like projections parallel to the lamellae of the exocuticle. The hyphae gradually extend inward, cleaving the lamellae of cuticle, and eventually enter the host's body cavity.
Ultrastructural localization of succinate dehydrogenase in a self-parasitic isolate of Saprolegnia megasperma
Authors: Murrin Sharon Faye , Nolan Richard A.
Published: April 2010

The enzyme succinate dehydrogenase (SDH, succinate: (acceptor) oxidoreductase, EC 1.3.99.1) was localized by the combined techniques of cytochemistry and electron microscopy in the hyphae of a self-parasitizing isolate of Saprolegnia megasperma Coker. The enzyme was localized in the mitochondrial membranes; its activity was inhibited by malonate. Electron-dense deposits, whose formation was not prevented by the addition of malonate, appeared outside of the hyphal cell walls. No evidence was found at the ultrastructural level within the vegetative hyphae for any abnormalities which could be linked to the phenomenon of self-parasitism.
Multiple forms of DNA-dependent RNA and polyadenylic acid polymerases from heterotrophically grown Rhodospirillum rubrum
Authors: Chow C. T.
Published: April 2010

Three, two major and one minor, distinct RNA polymerases have been isolated and partially purified from heterotrophically grown Rhodospirillum rubrum, a facultative photosynthetic bacterium. Associated with each of these three enzymes is a distinct polyadenylic acid polyemrase. All of these enzyme activities are dependent on DNA templates and are resistant to rifampicin and streptovaricin. The structural subunit composition, the response to various chemical compounds and DNA templates, and the properties of the products of these enzymes are studied in detail and compared with those of similar enzyme activities from other bacterial systems. Several unique features have been observed in the R. rubrum enzyme systems, such as an uneven incorporation of purine and pyrimidine nucleotides by the RNA polymerases, and the presence of a lag period in the polyadenylic acid polymerase activities.
Physarum polycephalum malate dehydrogenase: inhibitor analyses of the mitochondrial and supernatant isozymes
Authors: Teague W. Martin , Henney Jr. Henry R.
Published: April 2010

The effects of naturally occurring metabolites were tested on the malate dehydrogenase (L-malate: NAD+ oxidoreductase, EC 1.1.1.37) isozymes from the eucaryotic protist Physarum polycephalum. Several of the Krebs cycle intermediates were inhibitors for each isozyme indicating that a similar catalytic process was involved for both forms. The metabolites ATP, ADP, and AMP were inhibitors competitive with NAD for the mitochondrial isozyme but not the supernatant form. Several other nucleoside phosphates had no effects. Tests of protein sulfhydryl, arginine- and tyrosine-modifying reagents revealed a similar functional sensitivity by both isozymes to these reagents. Those results are compared with data on isozymes from more complex tissue with comments on the physiological significance of those combined data.
The use of cell cultures from the chorioallantoic membrane of chick embryos for studies of chlamydiae
Authors: Kordová Nonna , Wilt John C. , Martin Caroline F.
Published: April 2010

Cells of the chorioallantoic membrane of chick embryos were processed into monolayer cell cultures by a recently described technique of Cursiefen and Brecht. The cultures provided a sensitive substrate for the quantification of infectivity of C. psittaci strain 6BC and meningo-pneumonitis.
Improved selective medium for isolating Cylindrocladium crotalariae microsclerotia from naturally infested soils
Authors: Griffin Gary J.
Published: April 2010

Reduced development of fusaria and other undesired fungi, and improved recognition of Cylindrocladium crotalariae colonies on soil-dilution plates were accomplished by supplementing a previously used medium (sucrose–TBZ medium) with three quaternary ammonium compounds, replacing peptone with tyrosine, and increasing the concentration of sucrose to yield a water potential of −10 bars. These changes eliminated the need to treat soil with NaClO to control undesired fungi. The new medium, designated sucrose–QT medium, allowed increased recovery of C. crotalariae microsclerotia from all 16 naturally infested soils tested.
Use of sepharose-conjugated BCG antibodies for the purification of tuberculin-active components
Authors: Laguerre M. , Turcotte R.
Published: April 2010

Bacillus Calmette–Guérin (BCG) antibodies conjugated with CNBr-activated Sepharose 4B led to the isolation of tuberculin-active components from the protoplasmic materials of BCG. From these results, it is concluded that most of the tuberculin-active components (sensitins)have mycobacterial antigenic properties.
The biosynthesis of cellulose by Acetobacter xylinum and Acetobacter acetigenus
Authors: Colvin J. Ross , Leppard Gary G.
Published: April 2010

The morphological aspects of biosynthesis of cellulose by Acetobacter xylinum and Acetobacter acetigenus were studied by transmission electron microscopy of both freeze-etch replicas and sections of cellulose-free cells in suspension culture before and subsequent to the induction of cellulose synthesis. Also examined were freshly synthesized, thoroughly washed, cellulose pellicles. Thin sections of rapidly dividing, glucose-metabolizing cells of both species showed irregular features on the cell surface including a small polar invagination which sometimes contained or was associated with fibrils as fine as 3 nm in diameter of a substance which stains with electron-microscopic counterstains. Cellulose microfibrils in thin sections of freshly synthesized pellicles were coated with a surface material which also stained with the same counterstains (uranyl ions and lead ions). The effect of air-drying on freshly synthesized cellulose was striking. When examined by freeze-etching, thoroughly washed, never air-dried pellicles of both species showed a nascent form of cellulose fibril which consisted of a central, dense core surrounded by a sheath of amorphous gel. This sheath may be up to 100 nm wide. When the pellicle was air-dried and rehydrated before freeze-etching, the amorphous sheath was rare and shrunken but ordinary microfibrils of classical dimensions were visible. The sheath and core are sometimes closely associated with the envelope of the cells of both species. These observations can be interpreted in the context of recent advances in cellulose synthesis by assuming that chains of an initial, highly hydrated, intermediate polyglucan are released from the cell and that such chains associate to form a nascent fibril external to the cell but associated with the cell envelope. Air-drying of nascent fibrils converts them to classical microfibrils and this conversion is considered here in molecular terms.
Concentration of enteroviruses from large volumes of turbid estuary water
Authors: Sobsey Mark D. , Gerba Charles P. , Wallis Craig , Melnick Joseph L.
Published: April 2010

A method is described for the efficient concentration of viruses from large volumes of highly turbid estuary water. Virus in acidified sea water in the presence of aluminum chloride is adsorbed to a 10-in. (about 25.4 cm) fibreglass depth cartridge and 2- and 0.65-μm epoxy-fibreglass filters in series. This filter series is capable of efficiently adsorbing enteroviruses from 50 U.S. gallons (about 190 ℓ) of estuary water of varying salinity and turbidity. Adsorbed viruses were eluted from the filters with glycine buffer (pH 11.5) and the eluate reconcentrated by using a precipitate formed by the addition of ferric chloride. Viruses were eluted from this precipitate with fetal calf serum. Using this procedure, four different enteroviruses in 50 gallons (about 190 ℓ) of estuary water were concentrated 9 000- to 12 000-fold with an overall efficiency of 41%.
The orthonitrophenyl-beta-D-galactoside hydrolase from Pseudomonas aeruginosa (0:11 serotypes) is a superficial enzyme
Authors: Poindron Phillippe , Bourguignat Alain , Scheid Françoise , Lombard Yves
Published: April 2010

About 95% of the 0:11 strains of Pseudomonas aeruginosa was able to hydrolyze orthonitrophenyl-beta-D-galactopyranoside (ONPG), but was unable to use lactose. The ONPG-hydrolyzing enzyme was located essentially in the periplasm, as seen by biochemical and ultrastructural studies.
Influence of water potential on production of ethylene in soil
Authors: Cook R. J. , Smith A. M.
Published: April 2010

Ethylene production at different soil water potentials was studied in a high organic matter, red basaltic soil from a rain forest avocado grove of Queensland, Australia, and in a Latah silt loam from a recropped wheat field of Idaho, U.S.A. The soils were sealed under air or N2 in glass vials and incubated at 25 and 35 °C, respectively. Although the two soils differed in physical and chemical properties, in water content – water potential relationships, and in amount of ethylene produced, the relationship between ethylene production and water potential was virtually identical for both soils: maximal at saturation, reduced by −1 bar, and nearly prevented by −5 bars or slightly lower. Onset of ethylene production was earlier under N2, but total ethylene produced and the water potential–ethylene production relationship were about the same under both N2 and air. Osmotic adjustments of the soil water potential with KCl solutions resulted in more ethylene production between −1 and about −15 bars, but little or no ethylene production below −22 bars.The need for high water potential for ethylene production indicates that soil bacteria are more important than fungi in the ethylene production process in soil. The results further indicate that, because ethylene production is possible even to −5 bars or slightly lower, soil water availability should be no more directly limiting to this process in nature than it is, for example, to nitrification or other bacteriological processes in soil.
An in vitro system for the biosynthesis of spore cortex peptidoglycan
Authors: Pearce Susanne M.
Published: April 2010

A simple crude system for the incorporation of tritiated diaminopimelic acid (3H-DAP) into a polymer with characteristics of spore cortical peptidoglycan has been obtained from cells of Bacillus cereus var. alesti, harvested and disrupted in a French pressure cell, at the time of late cortex formation (sporulation stage 5). The small fraction of whole cells remaining in the homogenate were not responsible for the observed incorporation. The radioactive product was sensitive to digestion by lysozyme as is cortex formed in vivo. Preparations obtained at the same time of sporulation, from a mutant unable to form cortex, were unable to incorporate 3H-DAP into peptidoglycan. However, homogenates prepared at the time of germ cell wall formation (early stage 4) from both parent and cortexless mutant produced radioactive peptidoglycan which was more resistant to lysozyme as is germ cell wall produced in vivo in this species. Bacitracin and vancomycin inhibited incorporation of 3H-DAP into peptidoglycan by over 90% in both cell wall and cortical preparations. Methicillin caused a striking inhibition of 3H-DAP incorporation into peptidoglycan by the cortical system in contrast to its almost total lack of inhibition of the cell wall or germ cell wall systems. Over 90% of the DAP incorporated was the expected meso-isomer. 3H-DAP-labelled lipid intermediate was produced by the system. Cross-linking of newly synthesized material was observed. This in vitro system appears satisfactory for the further study of some aspects of the biosynthesis of cortical peptidoglycan.
Isolation and distribution of oligotrophic marine bacteria
Authors: Akagi Y. , Taga N. , Simidu U.
Published: April 2010

A useful plate culture method for isolating oligotrophic bacteria found in the low-nutrient environment of the open sea has been developed. The method uses a glass-fiber filter substitute for agar. Nutritional requirements of oligotrophic bacteria consisted of a dilute nutrient solution containing 16.8 mg C/ℓ total organic carbon aseptically added to the sterilized filter. Distribution of bacteria in oceanic and neritic seawater was determined using the membrane filter method. In the case of seawater containing less than 0.5 mg/ℓ dissolved carbohydrates, plate counts of oligotrophic bacteria were found to be several- to 100-fold greater than the heterotrophic bacterial counts enumerated by standard methods routinely used for enumeration. However, in seawater containing approximately over 0.5 mg/ℓ dissolved carbohydrates, heterotrophic bacterial counts were 10-fold greater than oligotrophic bacterial counts.
A single-bottle blood culture system: evaluation and comparison with two other systems
Authors: Qadri S. M. Hussain , Wende R. D.
Published: April 2010

A commercially available single-bottle blood culture system was evaluated at Ben Taub General Hospital, a Harris County District Hospital. Blood cultures from 1010 patients were examined with the Lederle Diagnostics one-bottle blood culture medium-SPS, Columbia broth (E-Vac, Pfizer), and an in-house-prepared brain heart infusion broth with p-aminobenzoic acid (PABA) and 0.1% agar. Of the 1010 patients examined, blood cultures from 211 (20.8%) were positive, yielding a total of 23 different species of microorganisms. Comparison of the results during clinical evaluation, as well as those from simulated blood cultures, showed that the Lederle Diagnostics blood culture bottle was as effective as the in-house-prepared brain heart infusion and commercially available Columbia broths for isolation of aerobes as well as anaerobes. The techniques used in the evaluation and the advantages of a single-bottle culture system are discussed.