bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of the fluorescent antibody technique to the study of an isolate of Beijerinckia in soil
Authors: Diem Hoang G. , Godbillon G. , Schmidt E. L.
Published: April 2010

Fluorescent antibody was prepared against a temperate-soil isolate of Beijerinckia obtained from a rhizosphere of rice growing in Camargue (France). The antibody did not cross-react with any of 6 species of Azotobacter, 4 species of Beijerinckia, or 44 unidentified soil bacteria isolated from a spectrum of rhizospheres, but strongly stained the homologous Beijerinckia isolate. The isolate grew well in autoclaved Camargue soil, but increased in numbers only slightly in nonsterile soil during 9 days. Preliminary examination of rice plants grown in the laboratory in soil from which the Beijerinckia was originally isolated did not show detectable Beijerinckia in the rhizosphere. The fluorescent antibody was sufficiently sensitive and specific to permit more extensive study of Beijerinckia in relation to nitrogen fixation in the rhizosphere of rice.
Serum effects on the response of mammalian cells to the exotoxins of Pseudomonas aeruginosa and Corynebacterium diphtheriae
Authors: Middlebrook John L. , Dorland Rebecca B.
Published: April 2010

The response of mammalian cells to Pseudomonas and diphtheria exotoxins was studied. A method was developed whereby the sensitivity of cells to these two toxins could be quantitated. The method is versatile and can be used to study the effects of toxins on many cellular metabolic or transport processes. The type of serum used in the culture medium significantly influenced the response of cells to the toxins. Calf, horse, and human sera protected cells while fetal calf serum did not. Precipitation with (NH4)2SO4 demonstrated the probable presence of toxin-specific antibody in the protective calf serum while none was detected in the nonprotective fetal calf serum. The level of antibody in calf serum, as titrated by hemagglutination, was sufficient to account for all the observed protection. It is suggested that fetal calf serum be used for all future cell culture studies of bacterial toxins.
Response of cultured mammalian cells to the exotoxins of Pseudomonas aeruginosa and Corynebacterium diphtheriae: differential cytotoxicity
Authors: Middlebrook John L. , Dorland Rebecca B.
Published: April 2010

The sensitivities of 21 mammalian cell lines to the exotoxins of Pseudomonas aeruginosa and Corynebacterium diphtheriae were measured. Each line exhibited 1–4 log differences in sensitivities to the two toxins. No species-specific sensitivities were noted for Pseudomonas exotoxin while diphtheria exotoxin was most potent in cells of monkey origin, followed by human and hamster cells. Rat-and mouse-derived cell lines were very in sensitive to diphtheria exotoxin. The rates of cellular intoxication by both toxins exhibited apparent first-order kinetics and were indistinguishable from one another when equipotent doses were used. Our preparation of diphtheria exotoxin appeared to have a slightly higher ADP-ribosylating efficiency than did Pseudomonas toxin. However, neither toxin exhibited cell line–specific differences in ribosylating efficiencies which could have explained the wide range in potencies for intact cells. Our results suggest that there are significant differences in the mechanisms of cellular intoxication by Pseudomonas and diphtheria exotoxins and that these differences probably exist in the attachment or internalization stages of toxin action.
Etude de la relation parasitaire initiale entre un virus du groupe L 1 de Gourlay et une population cellulaire d'Acholeplasma laidlawii
Authors: Roger Annie
Published: April 2010

The study of the relationships between MVL 51 virus, of the Gourlay group L 1, and the Mycoplasma cells of A. laidlawii during the first 35 min of infection leads to the conclusion that a "carrier state" has been established, free virus as well as infected and noninfected cells being present at the same time in the cultures.The evidence of a virus growth after 20 min of infection and the high level of remaining viable cells (1.15 × 108 CFU) at the end of the experiment also indicate that the carrier state should persist, at least for some time, being probably an important factor of the virus–cell relationship in the viral group L 1.
Stannous and cuprous ion oxidation by Thiobacillus ferrooxidans
Authors: Lewis A. J. , Miller J. D. A.
Published: April 2010

Oxidation of stannous chloride by Thiobacillus ferrooxidans was studied manometrically. At low stannous ion concentrations, initial oxidation rate was proportional to concentration. Optimum pH for oxidation was 2.3; optimum temperature was 37–40 °C. Spectrophotometry showed reduction of cytochromes in suspensions of whole cells on addition of ferrous, stannous, or cuprous salts. Cytochrome c reductase activity in cell-free extracts was assayed with ferrous, stannous, or cuprous ions as electron donors. It appears unlikely that an essential non-biological reaction, the reduction of ferric ions by stannous or cuprous ions, is involved. Growth of T. ferrooxidans was not obtained with either stannous chloride or stannous sulphate as sole energy source.
Amino acid uptake and protein synthesis in germinating spores of Saccharomyces cerevisiae
Authors: Steele S. D. , Miller J. J.
Published: April 2010

Spores transferred to germination medium incorporated exogenous lysine into protein within 20 min but required 2–3 h to begin incorporation of exogenous proline or alanine. During this time considerable uptake of amino acids into the intracellular pool occurred. Cycloheximide added to the germination medium inhibited incorporation of lysine into protein but did not lessen its accumulation in the pool. Spore germination was inhibited by cycloheximide.
Response of soil microbiota to selected herbicide treatments
Authors: Roslycky E. B.
Published: April 2010

Recommended concentrations of paraquat alone and its combination with each of linuron, diuron, atrazine, simazine, and simazine plus diuron exerted little effect on total populations of bacteria, actinomycetes, and fungi in Fox sandy loam under laboratory and simulated field conditions in 66 and 77 days, respectively. Respiration of the total microbiota in soil suspension was affected by the combinations as well as individual herbicides in various concentrations. Yet, the inhibition of the O2 uptake by any of these herbicides, including some extreme concentrations, was not permanent, indicating adaptation, or suppression of specific organisms. Only linuron in concentrations up to 20 μg/ml stimulated respiration of the soil.
Similar C-phycocyanins from two strains of thermotolerant cyanophyte Mastigocladus laminosus
Authors: Kao Oranda H. W. , Berns Donald S.
Published: April 2010

C-phycocyanin from two strains of the thermotolerant blue-green alga, Mastigocladus laminosus (NZ-DB2-m and I-30-m), that grow within different temperature ranges have been characterized with respect to aggregation, immunologic properties, subunit composition, and thermodenaturation. The critical thermal-denaturation temperature for phycocyanin from both strains of M. laminosus phycocyanin is 60 °C which is higher than that for mesophilic phycocyanin. Immunodiffusion studies have shown that these two strains of M. laminosus exhibit no antigenic differences and are closely related to the mesophilic Plectonema calothricoides and the thermophilic Synechococcus lividus (strain 3). Neither phenol nor α-naphthol has any effect on phycocyanin aggregation in these two strains of M. laminosus. There is also no enhancement of formation of large aggregates at their elevated temperature of cultivation. Furthermore, the phycocyanin of both strains of M. laminosus does not demonstrate any large amount of 19S or higher aggregates at any pH value. These observations suggest that the mode of adaptation of M. laminosus phycocyanin to high temperature is different from that previously encountered. It is also important to note that phycocyanin is essentially unchanged whether it is extracted from the same strain, M. laminosus (NZ-DB2-m), grown at either 50° or 37 °C.
Ultrastructure of soybean nodules. I: release of rhizobia from the infection thread
Authors: Bassett B. , Goodman R. N. , Novacky A.
Published: April 2010

Root nodules on soybeans (var. Clark 63) were examined by transmission electron microscopy 10–12 days after seed inoculation and planting. The cell infection process appeared identical in both effective nodules, induced by Rhizobium japonicum strain 138 (USDA) and in ineffective nodules, induced by strain 8-0 (Iowa). Electron micrographs are presented which suggest that rhizobia are freed from the infection thread by disintegration of the thread wall and compartmentalization of the disintegrated wall material in membrane-bound vesicles derived from the membrane surrounding the thread. As the thread wall is removed in this manner, the bacteria are released into the host cytoplasm by a process which encloses each in an envelope also derived from the thread membrane. Any thread wall material remaining around a bacterium after it has dissociated from the thread is removed from the envelope space by vesiculation of the membrane envelope. Thus, it appears that endocytosis of both the bacteria and the material composing the infection thread wall occurs during release of rhizobia into the host cell.
Pyocin sensitivity of Pseudomonas aeruginosa pretreated with antibiotics
Authors: Stevens Gwen S. , Ottolenghi Abramo C.
Published: April 2010

Strains of Pseudomonas aeruginosa exposed to subinhibitory concentrations of either polymyxin B, gentamicin, or carbenicillin were compared with untreated organisms for changes in sensitivity to pyocin. Pretreatment with polymyxin B or gentamicin resulted in a decreased sensitivity to pyocin, while carbenicillin pretreatment did not alter pyocin sensitivity.
Inhibition by sulfanilamide of sporulation in Saccharomyces cerevisiae
Authors: Colonna William J. , Gentile James M. , Magee P. T.
Published: April 2010

The antimetabolite sulfanilamide inhibits sporulation in Saccharomyces cerevisiae strain API. Cells exposed to sulfanilamide at various times during the sporulation process become progressively insensitive to the drug, although accumulation of sulfanilamide by the cells increases with time. Vegetative growth of API is practically unaffected by sulfanilamide; pregrowth of the cells in the presence of the drug does not prevent sporulation. Thus, inhibition is confined to the meiotic phase of the cell cycle. Sensitivity to sulfanilamide is independent of pH. Increasing the time cells are exposed to sulfanilamide results in a progressive reduction of ascus formation; however, the inhibition is reversible since sporulation can occur in cells exposed to the drug for > 24 h. The drug arrests the cells at a point before commitment to sporulation, since yeast cells exposed to sulfanilamide for 12 h do not complete the sporulation process when returned to vegetative medium, but resume mitotic growth instead. Meiotic nuclear division is largely prevented by sulfanilamide, and synthesis of RNA and protein is severely retarded. DNA synthesis is inhibited up to 50%; glycogen synthesis is ~90% inhibited. Other yeast strains showed varying sensitivity to sulfanilamide; homothallic strains were generally less affected.
Enzymatic hydrolysis of agar: purification and characterization of β-neoagarotetraose hydrolase from Pseudomonas atlantica
Authors: Groleau D. , Yaphe W.
Published: April 2010

Agarose is degraded by a β-agarase from Pseudomonas atlantica to neoagarooligosaccharides of degree of polymerization (DP) 4, 6, 8, and 10. A β-neoagarotetraose hydrolase cleaves the central β-linkage in neoagarotetraose and the β-linkage near the nonreducing end in neoagarohexaose and -octaose to yield neoagarobiose. The β-neoagarotetraose hydrolase was localized on or outside the cytoplasmic membrane, in the cell wall region. The enzyme was activated by NaCl, KCl, CaCl2, MnCl2, and MgSO4, has a Km of 3.4 × 10−3 M for neoagarotetraose, was free from β-agarase and α-neoagarobiose hydrolase activity, and showed no transglycosidic activity.
Induction of multispored asci in two-spored strains of Saccharomyces cerevisiae by amitrole
Authors: Ashraf M. , Miller J. J.
Published: April 2010

Although growth of two yeast strains characterized by consistent production of two diploid spores per ascus was inhibited in complex presporulation media containing amitrole, a fraction of the cells produced were able to form asci with more than two spores after transfer to acetate sporulation medium. Cells grown in a defined presporulation medium containing amitrole did not acquire this ability. The increase in spore numbers per ascus is attributed either to the induction by amitrole in growth medium of cells with more than one nucleus or to the restoration of normal meioses in the multispored asci.
Destruction de Microbacterium lacticum, Escherichia coli et Staphylococcus aureus au cours du séchage du lait par atomisation. I. Dénombrement sélectif des bactéries survivantes
Authors: Chopin A. , Mocquot G. , Graet Y. Le
Published: April 2010

In this paper a method which allows the measure of microbial death rate during spray-drying by means of a streptomycin-resistant mutant that can be grown on a streptomycin-containing agar is described. Plate counts of Microbacterium lacticum, Escherichia coli, and Staphylococcus aureus recovered from skim milk powders were done on plate count agar in the presence and absence of streptomycin and on various selective media. The powders were produced from evaporated milk previously inoculated with those organisms.Our results showed that the proposed method allows the recovery of 78% of M. lacticum, 61% of E. coli, and 100% of S. aureus that survived spray-drying. Recoveries of surviving E. coli on violet bile agar and brilliant green bile 2% were 34% and 29% respectively. Baird-Parker and mannitol salt agar media allow the recovery of all surviving S. aureus, thus showing that S. aureus cells did not lose their ability to grow in media containing 7.5% NaCl. Our results show that physiological injury of the cells during spray-drying differs from injury due to heating only. [Traduit par le journal]
Properties of 1-phosphofructokinase from Pseudomonas piutida
Authors: Bang Sookie S. , Baumann Paul , Sawyer Mark H.
Published: April 2010

The 1-phosphofructokinase (1-PFK, EC 2.7.1.56) from Pseudomonas putida was partially purified by a combination of (NH4)2SO4 fractionation and DEAE-Sephadex column chromatography. In its kinetic properties, this enzyme resembled the 1-PFK's from other bacteria. With the substrates fructose-1-phosphate (F-1-P) and adenosine triphosphate (ATP) Michaelis–Menten kinetics were observed, the Km for one substrate being unaffected by a variation in the concentration of the other substrate. At pH 8.0, the Km values for F-1-P and ATP were 1.64 × 10−4 M and 4.08 × 10−4 M, respectively. At fixed concentrations of F-1-P and ATP, an increase in the Mg2+ resulted in sigmoidal kinetics. Activity was inhibited by ATP when the ratio of ATP:Mg2+ was greater than 0.5 suggesting that ATP:2 Mg2+ was the substrate and free ATP was inhibitory. Activity of 1-PFK was stimulated by K+ and to a lesser extent by NH4+ and Na+. The reaction rate was unaffected by 2 mM K2HPO4, pyruvate, phosphoenolpyruvate, adenosine monophosphate, adenosine 3′,5′-cyclic monophosphate, fructose-6-phosphate, glucose-6-phosphate, 6-phosphogluconate, 2-keto-3-deoxy-6-phosphogluconate, or citrate. The results indicated that the 1-PFK from P. putida was not allosterically regulated by a number of metabolites which may play an important role in the catabolism of D-fructose.
Simultaneous presence of antiviral activity and its degrader in Bacillus extracts
Authors: Smart K. Marilyn , Steinberg Bettie M.
Published: April 2010

Extracts of uninfected Bacillus species ATCC 27877 cells contained both an antiviral activity and a degrader for this activity. The antiviral activity was stable to 90 °C, caused a rapid inhibition of phage adsorption, and resulted in a gradual loss of phage infectivity. When extracts were incubated at 37 °C, the degrader inactivated the antiviral activity and the degrader was retained. When the extracts were heated at 90 °C, the degrader was inactivated and the antiviral activity was retained. A comparison was made of these two activities in extracts from cells of various incubation ages. The apparent association of maximal antiviral activity with prespore cells seemed due to the high content of degrader in vegetative and stationary cells. Both antiviral activity and its degrader appeared to be characteristics of vegetative cells.
Cell wall of Fusarium sulphureum. II. Chemical composition of the conidial and chlamydospore walls
Authors: Schneider E. F. , Barran L. R. , Wood P. J. , Siddiqui I. R.
Published: April 2010

Examination of the conidial and chlamydospore walls of Fusarium sulphureum by electron microscopy showed the presence of two distinct layers of differing electron densities. These include a relatively narrow outer electron-dense layer and a broader more transparent inner layer. Both chlamydospore cell wall layers were thicker than the conidial wall. The outer wall of the chlamydospore wall was 30% thicker while the inner cell wall layer was 250% thicker than the corresponding cell wall layers in the conidia. During conidial differentiation to form chlamydospores there was a considerable augmentation of all cell wall components which varied from 7 to 26-fold per cell. The augmentation of the major cell wall constituents (N-acetylglucoseamine (NAG), glucose, and protein) and the vast increase in the inner cell wall of the chlamydospore wall indicated that these newly synthesized constituents are predominently located in the inner cell wall layer.The major carbohydrate constituents on a dry weight basis in both the conidial and chlamydospore walls were glucose, glucuronic acid, and N-acetylglycosamine (NAG). However, the proportion of these and the other carbohydrate constituents were different for both spore walls. Thus, the conidial wall contained about 50% less NAG and glucuronic acid but twice the glucose content of the chlamydospore wall. Protein was a major component of both spore walls (21.6%, conidial wall; 28.5%, chlamydospore wall). Amino acid analysis indicated differences in the types of protein present in the two spore walls. The lipid content of both conidia and chlamydospore was low (1–2%).
Experimental pulmonary infection of mice by tracheal intubation of Pseudomonas aeruginosa: the use of antineoplastic agents to overcome natural resistance
Authors: Schook Lawrence B. , Carrick Jr. Lee , Berk Richard S.
Published: April 2010

Tracheal intubation of viable Pseudomonas aeruginosa ATCC 19660 into the lungs of mice had no significant effect on the animals even with administration of organisms as high as 5.0 × 109 CFU. Animals treated with a single injection of an antineoplastic drug were, however, susceptible to bacterial challenge into the lungs. LD50 values of 4.1 × 107, 4.8 × 107and 1.0 × 108 CFU were obtained when animals were simultaneously infected and treated with methotrexate, vincristine sulfate, or cytosine arabinoside, respectively.
Occurrence of indole in cells of extremely halophilic bacteria
Authors: Kushwaha S. C. , Kates M. , Kramer J. K. G.
Published: April 2010

The neutral lipids of several halophilic bacteria contain a non-isoprenoid compound which was identified by its chromatographic and spectroscopic properties as indole.
Rapid solid-phase radioassay for staphylococcal protein A
Authors: Dickie N. , Konowalchuk J.
Published: April 2010

Solid-phase radioassay was applied to the determination of protein A after release from staphylococcal cells with lysostaphin. Assays can be completed in 60–90 min.
The effect on fungal growth of some 2,5-dihydroxy-1,4-benzoquinones
Authors: Brewer D. , Maass W. S. G. , Taylor A.
Published: April 2010

It has been shown that 2,5-dihydroxy-1,4-benzoquinones decrease vegetative growth and inhibit spore germination of 12 species of fungi belonging to six diverse genera. The nature of the substituents at the 3 and 6 positions of the quinone ring also affected their growth-inhibitory properties; generally those substituents of lower polarity inhibited growth at lower concentrations. As in the case of cochliodinol, chemical modification of the quinone group, or the hydroxyl groups of the quinone ring, in compounds of the polyporic acid series, also led to loss of biological activity.
Serological reactivity of chemical fractions of Mycoplasma bovis
Authors: Andrew Allan T. , Carter Paul B.
Published: April 2010

Crude chemical fractions, homogenates, and whole cells of Mycoplasma bovis were tested for serological reactivity using agar gel diffusion, ring precipitation, indirect hemagglutination, inhibition of growth inhibition (IGI), and complement-fixation (CF) tests. Only the IGI and the CF tests gave sensitive and reproducible serological information. Preliminary studies indicated lipids to be the serologically reactive components of M. bovis.
Effect of sodium chloride on growth and methane production of methanogens
Authors: Patel G. B. , Roth L. A.
Published: April 2010

The effect of up to 263.7 mM sodium chloride on the growth and methane production by pure cultures of Methanospirillum hungatii GP1, Methanobacterium MOH, Methanobacterium thermoautotrophicum, and an unidentified methanogen was studied. Growth and methane production by M. hungatii GP1 were not affected up to 97.3 mM NaCl but there was some inhibition of growth at higher concentrations. Growth of Methanobacterium MOH was independent of sodium chloride concentration within the range investigated. For the unidentified methanogen, optimum growth and methane production occurred at 15.2 mM NaCl, while growth of M. thermoautotrophicum was not affected by sodium chloride concentrations up to 15.2 mM. Concentrations over 15.2 mM were inhibitory to these two organisms. The 15 mM sodium chloride concentration used by some investigators appears suitable for isolation and cultivation of methanogens since all the organisms tested in this study exhibited good growth and methane production at this salt concentration.
Enterotoxin formation by Clostridium perfringens type A studied by the use of fluorescent antibody
Authors: Niilo L.
Published: April 2010

Fluorescein isothiocyanate-conjugated antibody to purified enterotoxin of Clostridium perfringens was used to study the intracellular formation of enterotoxin by this organism. Enterotoxin was detected at 4 h of growth at the end of the cell containing forespore. With the development of the spore, enterotoxin accumulation continued and involved the entire length of the cell until its lysis with the release of enterotoxin and mature spore. The spores did not contain demonstrable enterotoxin. Only a certain number of the sporulated cells of the enterotoxigenic strains studied produced this toxin. The amount of enterotoxin produced varied with sporulation percentage, and between strains and individual cells.
Transport of pantothenic acid in Lactobacillus plantarum
Authors: Germinario Ralph J. , Waller James R.
Published: April 2010

The characteristics of pantothenic acid (PA) transport into nonproliferating cells of Lactobacillus plantarum were studied. These characteristics included the effects of pH and temperature variations and the energy requirement for transport and binding of the vitamin. At pH 7.5 and 38 °C the intracellular vitamin was in the form of phosphopantothenic acid (P-PA) and was not exchangeable with external PA. Vitamin transport appeared separate from phosphorylation since significant free PA was observed only at elevated temperatures (e.g. 45 °C) and at low pH values. PA uptake and accumulation were energy-dependent, being inhibited completely by 10−2 M iodoacetate and the absence of glucose, exhibited pH and temperature optima of 7.5 and 38 °C, respectively, and were linear with time for at least 60 min. PA uptake exhibited substrate saturation. No free PA was observed when cells were incubated in PA concentrations above saturation levels. Apparent Km and Vmax values of 7.85 × 10−7 M and 5.35 μmol of PA/mg cells (dry weight) per minute, respectively, were determined from Lineweaver–Burk plots. Competitive inhibition of transport was observed with panthenol and pantoyl taurine. Ki values were, respectively, 3.55 × 10−5 M and 3.07 × 10−6 M. Pantoyl lactone, at concentrations which inhibited growth by 78%, had no effect on transport. The data reported suggest that PA transport is an active, mediated process and that transport may limit the phosphorylation of PA into P-PA. Inhibitor studies showed that PA transport was at least 150 times more sensitive to analogue inhibition than was growth itself, suggesting that transport of PA was not a limiting factor in the growth of L. plantarum.
Effet de l'aflatoxine B1 sur les activités enzymatiques de Bacillus thuringiensis (Berliner)
Authors: Boutibonnes P.
Published: April 2010

At 20 °C, aflatoxin B1, at a sublethal dose, decreases the activity of alkaline phosphatase (EC 3.1.3.1), α-glucosidase (EC 3.2.1.20), esterase (EC 3.1.1.1), chymotrypsin (EC 3.4.21.1), leucine aminopeptidase (EC 3.4.11.1), and phosphoamidase (EC 3.9.1.1) biosynthesis in Bacillus thuringiensis (Berliner).In contrast, at 41 °C no significant decrease was observed. At this temperature, the mycotoxin is not destroyed or metabolized and bacterial cells are resistant to the toxin.
Inhibition of attachment of Neisseria gonorrhoeae to tissue cells by goat milk antigonococcal immunoglobulin G
Authors: Ashton F. E. , Pasieka A. E. , Collins F. , Wallace R. , Diena B. B.
Published: April 2010

An immunoglobulin G (IgG)–containing fraction was isolated from milk, obtained from a goat before and after instillation of the mammary gland with Neisseria gonorrhoeae colony type 1 (T1). The presence of IgG and the absence of immunoglobulins-A and -M in this fraction was confirmed by immunodiffusion in gel and immunoelectrophoresis. Postinstillation IgG inhibited the attachment of the homologous strain of N. gonorrhoeae (T1) to tissue cells. The percentage of Rhesus monkey kidney cells with gonococci attached was 38.9% ± 6.4. Inhibition was significant (P < 0.01) when compared to the inhibitory effect of preinstillation IgG (73.5% ± 3.1) or buffer control (76.8% ± 2.8). Absorption of postinstillation IgG with rabbit anti-goat IgG or whole cell gonococci removed the inhibitory effect. Postinstillation IgG gave little or no inhibition of attachment (maximum 13%) of seven heterologous (T1) strains of N. gonorrhoeae to tissue cells. These results may provide a reason for recurrent gonococcal infection in humans despite the presence of circulatingantibody (IgG) to N. gonorrhoeae. Such an antibody, if present in secretions bathing the mucosa, may fail to prevent infection and colonization of the urogenital tract by a different immunotype of N. gonorrhoeae.
Immunofluorescence studies of Nitrobacter populations in soils
Authors: Rennie R. J. , Schmidt E. L.
Published: April 2010

Certain steps of a protocol to enumerate a bacterium directly in soil by immunofluorescence were studied with respect to the enumeration of Nitrobacter in soils of diverse properties. Maximal counts of Nitrobacter were obtained by varying factors involved in the release of bacteria from the soil. Differences with respect to these factors were related to soil-colloidal properties. Enumeration protocols modified with regard to soil properties were used with strain-specific fluorescent antibodies (FA) to enumerate Nitrobacter populations (a) in soil during storage, (b) in comparison with most probable number (MPN) enumeration, and (c) occurring in a spectrum of soil samples. FA counting was rapid and precise and gave counts generally 10- to 100-fold higher than obtained by MPN. Nitrobacter cells of the two serotypes studied, designated as agilis and Winogradsky, occurred in each soil at levels of 104–105 per gram.
Death and injury of Staphylococcus aureus during thermal treatment of milk
Authors: Firstenberg-Eden R. , Rosen B. , Mannheim C. H.
Published: April 2010

Staphylococcus aureus isolated from milk and grown in milk was heated in milk. The phenomena of death as well as injury was investigated in the range of 50 to 75 °C. The D60 value (decimal reduction time on salt-free medium) was 0.87 min, the D′60 value (decimal reduction time in salt-containing medium) was 0.62 min. Cultures were injured as soon as heating started. This initial thermal shock increased with increasing temperature. At 50–60 °C injury was more rapid than death. At > 60 °C death became faster than injury and the two processes coincided at 70 °C. The Z value was 9.46 °C and the Z′ value was 9.93 °C.
Cryopreservation of aster yellows agent in whole leafhoppers
Authors: Chiykowski L. N.
Published: April 2010

Aster yellows agent was preserved in an infectious state in leafhoppers (Macrosteles fascifrons) that had been fed on infected asters and then frozen and stored as whole insects at −64 °C for up to 2 years. No difference in infectivity was observed between extracts prepared from insects stored at −28 and −64 °C for up to 21 weeks. Three solutions (glycine + magnesium chloride, glycine + magnesium chloride + sodium sulphite, and phosphate-buffered saline) were found to be equally suitable in preparing extracts from frozen leafhoppers.
Release of flavine adenine dinucleotide on adsorption of the enzyme glucose oxidase to clays
Authors: Morgan H. W. , Corke C. T.
Published: April 2010

The adsorption–desorption characteristics of glucose oxidase holoenzyme (EC 1.1.3.4; β-D-glucose: oxygen-1-oxidoreductase), glucose oxidase apoenzyme, and the coenzyme flavine adenine dinucleotide (FAD) todays were studied. The fixation of apoenzyme, at a solution pH of 4.5, was rapid and almost complete within 1 h of incubation, since less than 5% of adsorbed apoenzyme was desorbed on changing the pH to 6.5. On the other hand, the fixation of the holoenzyme was much slower, since after I and 24 h of incubation at pH 4.5, raising the pH to 6.5 resulted in the desorption of 45 and 35% of initially adsorbed protein respectively. Flavine adenine dinucleotide was adsorbed to clay at pH 4.5, but only minimal adsorption occurred at pH 6.5.Experiments were performed to determine the release of flavenoid(s) into supernates when the holoenzyme was fixed to clay at pH 4.5. Determinations of the increases in fluorescence of supernates indicated that up to 80% of the original FAD in reacted enzyme was released into supernates. These supernates contained two compounds which possessed different Rf values than the reference compounds, flavine mononucleotide, riboflavine, lumichrome, and lumiflavine. The addition of apoenzyme to supernates obtained from holoenzyme–clay complex to reconstitute enzyme activity indicated that less than 3% of the original FAD could be detected in supernates.When the enzyme–clay complex structured at pH 4.5 was adjusted to pH 6.5, data on desorption of both protein and FAD allowed the conclusion that the coenzyme was desorbed as an integral part of the enzyme.
Caractérisation de bactéries telluriques assimilables à Pseudomonas maltophilia
Authors: Debette J. , Blondeau R.
Published: April 2010

The taxonomic position of some telluric non-fermenting Gram-negative bacteria collected into a phenon representing about a quarter of the soil isolates by an earlier numerical analysis is specified. The Shapiro–Chargaff coefficient determined by thermal-transition curves of the DNA and their hybridization by nitrocellulose filters method show a close affinity with Pseudomonas maltophilia.
The effects of osmotic pressure changes on the germination of Dictyostelium discoideum spores
Authors: Cotter David A.
Published: April 2010

Polyalcohols such as ethylene glycol and glycerol at 3 M penetrate and activate spores of Dictyostelium discoideum incubated at room temperature. Higher concentrations of ethylene glycol result in lysis upon suspension of spores in dilute phosphate buffer. Erythritol and arabitol at 3 M do not penetrate or activate D. discoideum spores.Air-dried spores or those incubated in 2 M sucrose solutions are not activated with the usual heat treatment of 45 °C for 30 min. The plasmolyzed spores are activated at temperatures above 45 °C when heated in the presence of 2 M sucrose for 30 min. The temperature for maximum activation and the temperature for thermal inactivation of spores are raised 7–10 °C in high sucrose concentrations. Long-term incubation of heat-activated spores in 2 M sucrose solutions does not result in a return to dormancy.Moderate sucrose concentrations near 0.2 M do not block the heat-induced activation process but must be removed from the spore population to prevent a return to dormancy within 6 h. Other polyhydric compounds at 0.25 M concentration also cause spore deactivation within 6 h of room temperature incubation. Oxygen uptake of spores undergoing deactivation in 0.18 M sucrose is inhibited as compared to control levels. Moderate concentrations of sucrose do not block the early events of postactivation lag and the spores accumulate at the end of the lag phase. The longer the spores remain unswollen at the end of the postactivation lag phase, the greater the percentage of spores which return to dormancy. The effects of moderate sucrose concentration (lowered water activity) are not duplicated by the same quantity of Ficoll, indicating that the colligative properties of the sucrose solutions are responsible for deactivation.
Effect of naturally occurring apatites on growth and morphology of algae
Authors: Smith E. A. H. , Mayfield C. I. , Wong P. T. S. , Silverberg B. A.
Published: April 2010

Crystals (30–100 μm) of selected naturally occurring apatite (Ca10 (PO4)6(OH, F)2) samples were added to P-free (<0.001 μg/ml total P) Bristol's medium (1–1000 μg/ml of apatite) as the sole source of ortho-PO43− The media were inoculated with washed, non-axenic cells of three chlorophycean algal species cultivated under PO43−-deficient conditions. Phase-contrast and scanning electron microscopy revealed that at low slurry densities (1–10 μg/ml of apatite), Ankistrodesnuis braunii (ATCC 2744) cells were morphologically distorted. At concentrations of 100 and 1000 μg/ml of apatite, more than 85% of the cells had undergone autospore formation within 7–10 days of incubation at 20 °C. Most autospores formed failed to germinate under high nutrient conditions. Scenedesmus longus (No. 1236) formed colonies when cultivated in Bristol's medium but daughter ceils displayed a Chodatella-like unicellular morphology when grown in apatite media. Test algal species (Chlamydomonas dysosmos, S. longus, A. braunii) showed a marked preference for growth on apatite crystals over non-nutritive surfaces. Unialgal and mixed-algal cultures produced an extensive matrix of extracellular fibrous material in response to growth on crystals at concentrations greater than 10 μg/ml of apatite.
Glycogen synthesis by amylosucrase from Neisseria perflava
Authors: MacKenzie C. R. , Johnson K. G. , McDonald I. J.
Published: April 2010

Amylosucrase (sucrose: 1,4-α-D-glucan 4-α-glucosyltransferase; EC 2.4.1.4) which mediates the transfer of the glucosyl moiety of sucrose to a growing α-1,4-glucan chain is a constitutive enzyme of Neisseria perflava. The products of enzymic action are insoluble glycogenlike polysaccharides and fructose, the latter being a competitive inhibitor of the enzyme (Ki = 20 mM). The enzyme is extremely stable and appears to bind very tightly to its polymerized product. Properties of product-bound enzyme reflect those of the native complex.
A dendrogram of plant viruses
Authors: Tremaine J. H.
Published: April 2010

To facilitate the recognition of plant viruses with similar characteristics a dendrogram of characterized viruses was constructed. The sequence of criteria included: type of nucleic acid; single or double stranded; presence or absence of lipid envelope; helical or nonhelical symmetry; and divided or single genome. Nonhelical RNA viruses with divided genomes were further divided into viruses with one or more than one capsid size. Those with one capsid size were subdivided into viruses with one or more than one sedimenting component. Nonhelical RNA viruses with a single genome were divided according to their RNA size, and their sensitivity to sodium dodecyl sulfate and ethyIenediaminetetraacetic acid.
Inhibition of diptheroid esterase by Micrococcus luteus
Authors: Bibel D. J. , Smiljanic R. J.
Published: April 2010

Micrococcus luteus produced a diffusible, esterase inhibitory factor (EIF) which inhibited the activity of cutaneous diphtheroid esterases on Tween 80–CaCl2 agar media. Esterases of Staphylococcus, Micrococcus, Bacillus, and Serratia were not susceptible. EIF did not appear to combine with the substrate or to prevent enzyme synthesis; it was unable to reverse the precipitation of calcium oleate. The composition of the medium, especially peptones, influenced the production of EIF. EIF was synthesized in the absence of diphtheroids, but production required the presence of Tween. The interaction was observed on agar medium of pH 5.5–8.5, at 25–43 °C, under an atmosphere of 10–20% CO2, in the presence of urea, but not after the addition of NaCl or dextrose. Supernatants of broth cultures had to be concentrated to detect EIF. Crude dialyzed and concentrated preparations of EIF withstood 60 °C for 60 min but were inactivated after 100 °C for 10 min. EIF may possibly be associated with a lipoid substance, since it did not precipitate in ethanol.
The effect of ionic surface-active agents on macroconidial plasma membrane of Fusarium sulphureum
Authors: Miller R. W. , Barran L. R.
Published: April 2010

A method was developed for direct assessment of changes in cytoplasmic volume and permeability of plasma membranes of intact cells to divalent cations. This technique, which utilized an amphipathic spin label partitioning between intracellular aqueous and hydrophobic environments, allowed estimates of the proportion of cells in a homogeneous population sustaining membrane damage associated with Ni+2 and water permeability and the rate at which such damage was induced.Several specific effects of cationic and anionic surfactants on the macroconidial plasma membranes of Fusarium sulphureum Schlect (isolate 1) were distinguished on the basis of detergent concentration and charge. The induction of water uptake by the cells was found to be an effect of dodecylguanidine acetate (Dodine), a cationic fungicide, at low concentration. At higher concentrations (>5 × 10−5 M) both the impermeability of the plasma membrane to divalent cations and the ability to accumulate actively L-phenylalanine were lost irreversibly and cell lysis occurred above 5 × 10−4 M. Sodium dodecyl sulfate eliminated divalent cation impermeability more rapidly than Dodine but was less effective in inhibiting active transport function. An antagonistic effect between cationic and anionic detergents was observed.
Epitheliocystis disease in the striped bass Morone saxatilis from the Chesapeake Bay
Authors: Zachary Arthur , Paperna Ilan
Published: April 2010

Epitheliocystis disease in the gills of the striped bass Morone saxatilis from Chesapeake Bay was studied using light and electron microscopy. The epitheliocystis infection appeared synchronous in that all capsules on a single host were at the same stage of development. The disease appeared to begin in a single cell on the gill lamella, which gradually enlarged to form a large cyst, encapsulated by a thick cellular capsule of epithelial origin. The epitheliocystis inclusion was filled with cells of the general morphology and size of rickettsiae; however, the infection was atypical for rickettsiae in that the cells had a dense central nucleoid region and they developed within an inclusion separated from the host cytoplasm.
The taxonomy of some new isolates of dissimilatory sulfate-reducing bacteria
Authors: Skyring G. W. , Jones H. E. , Goodchild D.
Published: April 2010

The interrelationships between 92 isolates of sporing and non-sporing sulfate-reducing bacteria were determined. Of the 116 biochemical and physiological characteristics examined, only 25 were useful for discrimination of groups. Responses to most of the tests were negative. A similarity coefficient and a principal component factor analysis of these data were made. The deoxyribonucleic acids buoyant densities (DNA) from all strains and the electrophoretic properties of adenylylsulfotransferase (ATP-sulfurylase), adenylphosphosulfate (APS)-reductase, and sulfite reductase of selected isolates were determined. On the basis of these various data eight groups were recognized. Isolates of seven of these groups appeared to be similar to one or more named strains. Isolates of group E (DNA buoyant density, 1.708) were different from previously named strains. Sporing strains were not isolated from the Papua New Guinea location. Halophilic and non-halotolerant strains were isolated from highly saline locations in Australia.Results pertinent to the taxonomy and ecology of the sulfate-reducing bacteria are discussed.
Inhibition of antigen and mitogen-induced lymphocyte transformation by fetal calf serum
Authors: Araby I. I. El , Chernesky M. A. , Dent P. B.
Published: April 2010

Use of fetal calf serum as a serum supplement in whole blood microcultures of human lymphocytes resulted in a significant suppression of in vitro stimulation with herpes simplex virus (type 1) antigen, purified protein derivative, and phytohemagglutinin. If the response to viral antigen is weak in autologous serum it may be completely missed if cultures are carried out in fetal calf serum.
A rapid method for the determination of cellular protein in the presence of elemental sulfur
Authors: Proteau Gérald , Silver Marvin
Published: April 2010

Cellular protein in the presence of elemental sulfur is determined by the Folin reagent after treatment with benzene. Using this procedure a generation time of 46.2 ± 4.2 h was observed for Thiobacillus acidophilus grown on elemental sulfur.
Heterogeneity and the modelling of bacterial spore death: the case of continuously decreasing death rate
Authors: Sharpe Ken , Bektash Roger M.
Published: April 2010

Models for the inactivation of bacterial spores for the case of continuously decreasing death rate are reviewed and extended to show that it is not possible to distinguish between one particular model based upon the innate heterogeneity of the population and that based upon the acquisition of heat resistance during the heating process. Two innate heterogeneity models have been fitted to published data.
Composition chimique et degradation des parois d'une souche sauvage et d'un mutant blanc du champignon Drechslera sorokiniana
Authors: Al-Rikabi K. H. , Bonaly R.
Published: April 2010

The cell walls of the fungus Drechslera sorokiniana and an albino mutant have been studied to determine if disappearance of pigment also involves an important modification of the chemical structure. The albino mutant has lost, besides the pigment, pentose, xylose, and part of galactose and mannose. The protein contents as well as those of hexosamine and chitin are not modified. After treatments of the walls with 2 M NaOH – 0.5 M H2SO4 and with ethylenediamine identical compounds are isolated from the two walls; however, cell walls of the mutant are more easily and more extensively degraded than those of the wild type. This difference in resistance is not only due to the presence of pigment but also to a different architectural structure of the two cell walls.
The response of Azotobacter chroococcum to oxygen: superoxide-mediated effects
Authors: Buchanan Alfred G.
Published: April 2010

Nitrogenase in Azotobacter chroococcum whole cells was inhibited by enzymically generated superoxide anion (O2−), hydrogen peroxide, and ethyl hydrogen peroxide. The degree of inhibition produced by O2− was related to the quantity of oxygen supplied to the organisms in continuous cultures. O2− also inhibited oxygen uptake by whole cells. These O2−-mediated inhibitions were prevented by bovine superoxide dismutase. The quantities of superoxide dismutase (SOD), and catalase associated with cells grown under varying oxygen concentrations were determined. The role of hydrogen peroxide, and of the hydroxyl radical (∙OH) in nitrogenase inhibition was examined. The response of Azotobacter chroococcum to oxygen was evaluated with respect to the observed effects of O2− on the organism, and some explanation is given to account for nitrogenase sensitivity to oxygen.
Studies on Agrobacterium tumefaciens. VII. Avirulence induced by temperature and ethidium bromide
Authors: Lin Bor-Chian , Kado C. I.
Published: April 2010

When tumorigenic strains of Agrobacterium tumefaciens were subcultured at temperatures between 31.5 and 37 °C or in broth containing ethidium bromide, they lost their capacity to induce tumors in tomato plants. The sensitivities of curing virulence (tumorigenicity) depended on the density of the population of cells, fewer cells (100/ml) being more sensitive to curing than higher densities (106/ml). The loss of virulence need not require the total loss of the virulence-specifying plasmid, but may result from a loss of a small segment of that plasmid. Virulent strains made avirulent by temperature or ethidium bromide treatment still harbor a large plasmid of 70–80 megadaltons size compared with the 100-to 120-megadalton plasmid in the untreated strains.
Occurrence in Monia rectirostris (Cladocera: Daphnidae) of a parasite morphologically similar to Pasteuria ramosa(Metchnikoff, 1888)
Authors: Sayre R. M. , Wergin W. P. , Davis R. E.
Published: April 2010

Pasteuria ramosa, a bacterial parasite of the cladocerans Daphnia pulex and D. magna, was described by Metchnikoff in 1888. Because the organism could not be cultured, it was subsequently lost. However, the original illustrations and descriptions of the life cycle of P. ramosa are similar to a bacterial spore parasite of nematodes (BSPN) that was recently described in Meloidogyne. As a result of these similarities, a search for P. ramosa was initiated. An organism resembling P. ramosa was found infecting Moina rectirostris, a member of the Daphnidae and a new host for the bacterium. Photomicrographs and scanning electron micrographs of the parasite indicated that the morphology of this organism was similar to the descriptions and illustrations presented by Metchnikoff. Morphological features of this newly described parasite also indicate that the bacterium is similar to the BSPN.
Partial characterization of the mode of action of benzoic acid on aflatoxin biosynthesis
Authors: Uraih Nduka , Cassity Timothy R. , Chipley John R.
Published: April 2010

Aflatoxin production by a toxigenic strain of Aspergillus flavus was greatly reduced by benzoic acid and sodium benzoate in synthetic media. The reduction was accompanied by the appearance of a yellow pigment. Spectral analyses partially characterized this pigment as closely related to an acetyl derivative of a versiconal-type compound. A cell-free extract prepared from A. flavus grown in synthetic media was active in converting this yellow compound into aflatoxin B1 in the presence of reduced nicotinamide adenine dinucleotide phosphate at 25 °C (pH 7.4). In the presence of benzoic acid and its salt or autoclaved cell-free extract, conversion of yellow compound to aflatoxin B1 was prevented. These results suggest that the yellow compound is an intermediate in the secondary metabolic cycle involved in aflatoxin B1 production. Benzoic acid, sodium benzoate, or autoclaving the cell-free extract appear to have respectively blocked or denatured an enzymatic step late in the biosynthetic pathway of aflatoxin B1.