bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic relationship between pUB110 and antibiotic-resistant plasmids obtained from thermophilic bacilli
Authors: Hoshino Takayuki , Ikeda Takayuki , Furukawa Kensuke , Tomizuka Noboru
Published: May 2010

The molecular relationship between pUB110 (Kmr, 4.4 kilobases (kb)) and antibiotic-resistant plasmids from thermophilic bacilli, pTHT15 (Tcr, 4.5 kb) and pTHN1 (Kmr, 4.8 kb), were studied by blot hybridization. Extensive homology was observed between pUB110 and pTHT 15 at the region which includes the replication origin. Incompatibility studies revealed that pTHT 15 and pUB110 were slightly incompatible in Bacillus subtilis but that they were apparently compatible in B. stearothermophilus. This difference in incompatibility between pTHT15 and pUB110 in the two host cells might be due to a difference in the copy number of pTHT15 in the two organisms. From the results of blot hybridization, mode of kanamycin inactivation, and DNA sequencing, it was determined that pTHN1 encoded the identical gene for kanamycin nucleotidyl transferase as that of pUB110. All three plasmids pTHT15, pTHN1, and pUB110 shared a common DNA homology at the in vitro membrane-binding region.
Production, purification, and properties of thermostable xylanase from Clostridium stercorarium
Authors: Bérenger Jean-François , Frixon Chantal , Bigliardi Jacqueline , Creuzet Nicole
Published: May 2010

The production of xylanase and endoglucanase in Clostridium stercorarium has been studied in different conditions. Activities were higher when the organism was grown on xylan and cellulose than on soluble substrates. Catabolite repression of xylanase synthesis occurred when glucose and other readily metabolizable substrates were added during growth on cellulose. Three endoxylanases, A, B, and C, from culture filtrate were purified to homogeneity. Most of the properties of xylanases A, B, and C were similar (optimum pH in the range of 5.5–7.0 at 65 °C; isoelectric pH, 4.4–4.5; Km values of 2.9–3.7 mg/mL). The enzymes were inactivated by Hg2+ and p-chloromercuribenzoate but slight inhibition was obtained with more specific thiol reagents such as 5,5′-dithiobis(2-nitrobenzoic acid) and N-ethylmaleimide. Carbohydrate content (3–19%) and half-life (2 min 30 s to 90 min) varied. Patterns of hydrolysis demonstrate that the three enzymes are endo-splitting enzymes able to break down xylan at random giving xylobiose and xylotriose as the main end products. The three enzymes exhibited immunological cross-reactivity.
Comparison of the mitochondrial endonucleases from Neurospora crassa and Saccharomyces cerevisiae
Authors: Tigerstrom Richard G. von , Stelmaschuk Sheilah
Published: May 2010

The endonucleases from Neurospora crassa and Saccharomyces cerevisiae are not closely related antigenically. They also differ with respect to their activity at pH 8, their degree of hydrophobicity, and their sensitivity to elevated temperatures. However, the two nucleases have similar specific activities, are inhibited by EDTA, and have nearly identical substrate specificities. Since the enzymes also have the same mode of action and intracellular location, these similarities may indicate that they have the same physiological role despite their structural differences.
Binding of α2-macroglobulin and haptoglobin to Actinomyces pyogenes
Authors: Lämmler Christoph , Chhatwal Gursharan S. , Blobel Hans
Published: May 2010

All 25 cultures of Actinomyces pyogenes tested in the present study bound 125I-labelled human α2-macroglobulin with a mean binding of 65.6%. Thirteen cultures also bound 125I-labelled human haptoglobin with a mean of 51.5%. None interacted with fibrinogen, fibronectin, immunoglobulin G, or albumin. Twenty-eight cultures representing other species of actinomycetaceae did not show any interaction with α2-macroglobulin, haptoglobin, and other plasma proteins tested. The binding of α2-macroglobulin and haptoglobin to A. pyogenes was saturable and could be completely inhibited by the respective unlabelled plasma proteins. The binding of α2-macroglobulin could not be inhibited by unlabelled haptoglobin. On the other hand, α2-macroglóbulin blocked the binding of haptoglobin, possibly by steric hindrance. Treatment of the bacteria with trypsin reduced their binding activities for α2-macroglobulin and haptoglobin indicating the protein nature of the binding sites. Exposure to heat (1 h, 80 °C) significantly diminished the binding activity for haptoglobin, but not that for α2-macroglobulin. The binding of α2-macroglobulin and haptoglobin could be an important feature in the classification of A. pyogenes among the members of actinomycetaceae.
Cyanide degradation by Rhizopus oryzae
Authors: Padmaja G. , Balagopal C.
Published: May 2010

Rhizopus oryzae, a mucoraceous fungus associated with the postharvest spoilage of cassava was found to effectively metabolize cyanide. Degradation of cyanogenic glycosides of cassava by R. oryzae was studied by growing the organism in potato dextrose broth with and without linamarin and potassium cyanide. The influence of adaptation of the organism to low and high cyanide concentrations on both growth and the release of extracellular rhodanese into cyanide-containing media was studied. Nonadapted cultures of R. oryzae grow poorly when compared with the cyanide-adapted cultures. However non-adapted R. oryzae cultures released large quantities of rhodanese when compared with the adapted ones. Potassium cyanide (1.0 mM) was found to be an efficient inducer of rhodanese whereas potassium cyanide (5.0 mM) repressed the release of rhodanese. A significant inductive effect was produced by thiosulphate and thiocyanate. Linamarin repressed the rhodanese activity of cultures during the growth phase. Rhizopus oryzae also elaborated extracellular linamarase during its growth in broth with and without linamarin. This study revealed the potential use of R. oryzae in detoxifying the cyanogenic glycosides in cassava feed and food preparations as well as in the effective disposal of cyanide in industrial wastes.
Morphological studies of N-acetylglucosamine induced germ tube formation by Candida albicans
Authors: Hubbard Michael J. , Sullivan Patrick A. , Shepherd Maxwell G.
Published: May 2010

In N-acetylglucosamine induced germ tube formation by Candida albicans, multiple (up to five) protuberances appeared within 90 min at 37 °C on each yeast cell. The protuberances were extensions of the cytosol and contained vesiclelike structures. Usually only one protuberance subsequently developed into a germ tube. The germ tubes emanated from all aspects of the cell surface but seldom from the budding (long axis) poles. Pseudohyphae, which originated from the budding pole, exhibited a marked constriction at the site of emergence and were 0.6–2.5 μm in diameter compared with a diameter of 0.6–0.8 μm for germ tubes. The presence of septa confirmed that germ tubes are precursors of septate mycelia. Ultrathin-section transmission electron microscopy of aldehyde plus osmium fixed cells revealed electron-lucent walls with a thin electron-dense outer layer. A fibrillar border was also routinely associated with germ tubes. Poststaining with potassium permanganate revealed, in addition, a previously invisible fuzzy layer on the outer region of the cell wall which extended over bud scars and germ tubes and which coalesced at sites of contact between cells.
Effect of bacteria on the inactivation and adsorption on clay minerals of reovirus
Authors: Lipson Steven M. , Stotzky G.
Published: May 2010

This investigation studied the antiviral activity of, and the utilization of viruses as substrates by, bacteria. Reovirus type 3 and bacterial species representative of those endemic to sewage, aquatic, and terrestrial habitats were used in the model systems. Culture supernatants from Bacillus subtilis maintained for 5 days in a minimal salts medium displayed antiviral activity, but supernatants from Escherichia coli or Serratia marcescens did not. Both live and toluene-killed cells reduced the inactivation of reovirus during 4 days of incubation at 23 ± 2 °C. This protective effect was more pronounced with killed than with live cells of B. subtilis, confirming the presence of an antiviral component(s) in this species and indicating that the component(s) was metabolic in origin. When reovirus was presented to these bacteria as a sole source of carbon, some growth (determined spectrophotometrically) of B. subtilis and S. marcescens occurred with reovirus concentrations of 3.1 × 106 and 8.2 × 106 mean tissue culture infective dose-fifty∙mL−1, respectively. Growth of S. marcescens did not occur with a reovirus concentration of 8.0 × 104 mean tissue culture infective dose-fifty∙mL−1, nor did that of E. coli with any virus concentration used in this study. Adsorption of reovirus on kaolinite was enhanced by the culture supernatant from S. marcescens and on montmorillonite, albeit to a lesser extent, by that from E. coli. The effect of culture supernatants from B. subtilis on the adsorption of reovirus on clay minerals could not be determined, as a result of the antiviral component produced by these cells. The virus was not adsorbed on the bacteria.
The localization and activity of Cellulomonas xylanase on sugarcane bagasse pith
Authors: Rodríguez H. , Enríquez A. , Volfová O.
Published: May 2010

Xylanase activity was found both free and bound to the cells and (or) the substrate during the first growth phase of Cellulomonas on bagasse pith. At the same time, rapid degradation of the bagasse hemicellulose was observed. The enzymes became bound mainly during the second growth phase, during which hemicellulose degradation was still detected, although at a lower rate. Intracellular xylanase activity was about one-tenth of the activity detected outside the cell during this phase. At the end of growth, 89% of the bagasse hemicellulose had been consumed.
Experimental congenital syphilis in rabbits
Authors: Fitzgerald Thomas J.
Published: May 2010

A model for congenital syphilis in rabbits was developed based on multiple intravenous injections of pregnant does with high concentrations of Treponema pallidum. A total of 48 pregnant does and 394 newborns were evaluated. Indications of in utero infection included a 7- to 10-fold increase in fetal mortality and a 49% reduction in birth weight. The size of the stillborns varied. Some developed to normal size, whereas others were poorly developed, hemorrhagic, and 1/10th normal size. Fetuses were surgically removed after 25 to 28 days of gestation and extracts of the fetal tissues were injected into adult rabbits. Syphilitic lesions resulted demonstrating the presence of T. pallidum within the fetal tissues. Treponemes were also demonstrated within splenic tissue from a 1-week-old newborn. Isolated amniotic membranes were placed in Franz Biologic chambers. Viable organisms readily penetrated through the amnion but heat-inactivated organisms did not. Further evidence for in utero transmission of organisms was provided by intradermal injection of 6- to 7-week-old newborns. In control newborns in which the does were not infected during pregnancy, lesions occurred at 90% of the sites injected and developed in typical fashion. In newborns from does infected during pregnancy, lesions occurred in 18% of the sites injected and developed in atypical fashion (flat, nonulcerating, rapid healing). Finally, overt congenital syphilis did not occur if the does were immune prior to pregnancy, then infected with T. pallidum during pregnancy. The percent mortalities and birth weights of newborns were equivalent to control newborns from noninfected does.
Effect of carbon dioxide on growth of Pseudomonas putida ATCC 11172 on asparagine, citrate, glucose, and lactate in batch and continuous culture
Authors: Molin Göran
Published: May 2010

The growth of Pseudomonas putida ATCC 11172 on L-asparagine, citrate, D-glucose, and L-lactate was followed in air and in 40% CO2 + air, using batch and carbon-limited continuous cultures. Batch cultures in air utilized a mixture of the carbon sources simultaneously. However, a change to 40% CO2 favoured the utilization of glucose. The maximum specific growth rate (μmax) in air was about 0.3 h−1 on glucose and 0.6 h−1 on the other carbon sources. In CO2, the μmax for glucose was reduced by 16% compared with almost 60–70% for the others. An order of preference for the different carbon sources in continuous cultures was determined by comparing the dilution rates at which the different carbon sources started to appear in the effluent. Glucose was the first compound to appear as the dilution rate increased (lowest preference when grown in air). In 40% CO2, the μmax for glucose was slightly higher than the others and the recorded preference for glucose in continuous culture was equal to that for citrate but was somewhat lower than that of lactate and asparagine. D-Gluconate and glucono-δ-lactone were produced as a step in the utilization of glucose. The D-gluconate production was enhanced by CO2.
Interaction of Laterispora brevirama and the mycoparasites Sporidesmium sclerotivorum and Teratosperma oligocladum
Authors: Ayers W. A. , Adams P. B.
Published: May 2010

Laterispora brevirama, a fungus found in association with the Sclerotinia mycoparasites Sporidesmium sclerotivorum and Teratosperma oligocladum, was markedly similar in morphology to the other two fungi yet differed in its parasitic activity. Laterispora brevirama colonized and proliferated on sclerotia of Sclerotinia minor which had been infected first by Sporidesmium sclerotivorum or T. oligocladum but did not do so in the absence of these specific mycoparasites. Macroconidia of L. brevirama germinated in soil in response to sclerotia infected by Sporidesmium sclerotivorum, and to hyphae of Sporidesmium sclerotivorum. Aqueous extracts of hyphal mats of Sporidesmium sclerotivorum stimulated maximal germination of macroconidia in vitro, although other nutrients also supported germination to a lesser extent. In culture and in its parasitic phase in soil, L. brevirama formed specialized contact cells on the hyphae of Sporidesmium sclerotivorum and T. oligocladum, but never appeared to invade hyphae. Laterispora brevirama added to soil at 1000 macroconidia/g, along with Sporidesmium sclerotivorum at the same concentration, did not influence the rate of infection and destruction of sclerotia of Sclerotinia minor by Sporidesmium sclerotivorum. The resulting numbers of new macroconidia of Sporidesmium sclerotivorum formed in the soil from energy derived from the infected sclerotia, however, were reduced by the presence of L. brevirama. Laterispora brevirama is either a direct parasite of Sporidesmium sclerotivorum and T. oligocladum or is a secondary parasite of Sclerotinia spp. that is active only in association with either of the two primary mycoparasites.
Tolérance au zinc et au cadmium et accumulation du zinc par les bactéries marines à Gram négatif : relations avec leur type respiratoire
Authors: Gauthier M. J. , Breittmayer V. , Clément R. , Flatau G. N. , Amiard J. C.
Published: May 2010

A statistical analysis of relations between the respiration type of Gram-negative marine bacilli and their resistance to zinc and cadmium or their ability to concentrate zinc was carried out on 453 strains isolated from seawater and oysters. A highly significant relation was found between the respiratory type of strains and their resistance (strict aerobes were 3 times more sensitive than facultative aerobes) or their binding capability (strict aerobes accumulated 2.5 times more zinc)
Effect of O2 on vesicle formation, acetylene reduction, and O2-uptake kinetics in Frankia sp. HFPCcI3 isolated from Casuarina cunninghamiana
Authors: Murry Marcia A. , Zhongze Zhang , Torrey John G.
Published: May 2010

The effect of the partial pressure of oxygen (PO2) on the formation of vesicles, which are thought to be the site of N2 fixation in Frankia, was studied in HFPCcI3, an effective isolate from Casuarina cunninghamiana. Unlike other actinorhizal root nodules, vesicles are not produced by the endophyte in Casuarina nodules. However, in culture under aerobic conditions, large, phase-bright vesicles are formed in HFPCcI3 within 20 h following removal of [Formula: see text] from the culture medium and reach peak numbers within 72 to 96 h. In vivo acetylene reduction activity parallels vesicle formation. Optimum rates of acetylene reduction in short-term assays occurred at 20% O2 (0.2 atm (1 atm = 101.325 kPa)) in the gas phase. O2 uptake (respiration) determined polarographically showed diffusion-limited kinetics and remained unsaturated by O2 until 300 μM O2. In contrast, respiration in [Formula: see text]-grown cells was saturated by O2 between 8 and 10 μM O2. These results indicate the presence of a diffusion barrier associated with the vesicles. Vesicle development was repressed in cells incubated in N-free media sparged with gas mixtures with PO2 between 0.001 and 0.003 atm. Nitrogenase was induced under these conditions, but acetylene reduction was extremely O2 sensitive. The kinetics of O2 uptake as a function of dissolved O2 concentration in avesicular cells were similar to those in [Formula: see text]-grown cells indicating the lack of a diffusion barrier. These results demonstrate that vesicle formation and the development of the O2 protection mechanisms of nitrogenase are regulated by ambient PO2 in HFPCcI3.
Antigenic differences among several Trichoderma isolates
Authors: Barak Rina , Maoz Arieh , Chet Ilan
Published: May 2010

Antisera against conidia of several Trichoderma isolates were raised in rabbits and tested by agglutination and immunofluorescence. Six serotypes were characterized and the differences in their surface properties studied. The serological differences among the isolates did not always reflect their taxonomic differences. Serological similarities were found in several instances between conidia and hyphae of the same isolate. Periodate oxidation of the conidia inhibited their serological reaction whereas trypsin had no effect. The use of specific antisera for serotyping Trichoderma isolates is discussed.
Changes in root morphology of wheat caused by Azospirillum inoculation
Authors: Kapulnik Yoram , Okon Yaacov , Henis Yigel
Published: May 2010

Wheat seeds (Triticum aestivum L.) were inoculated with Azospirillum brasilense Cd, Sp7, the local isolate Cd-1, and with other types of bacteria. Inoculation with 105 to 106 colony-forming units of Azospirillum caused the largest root elongation and total root surface of seedlings whereas 108 to 109 colony-forming units of Azospirillum caused inhibition of root development. Similar effects were obtained in 10 different cultivars of wheat inoculated with Azospirillum. Scanning electron micrographs of inoculated wheat root segments showed denser and longer root hairs as compared with the control inoculated with dead cells. This effect was less apparent in more mature roots. In inoculated roots bacteria were located mainly on the cell elongation area and on the bases of root hairs, but fewer bacterial cells were present on the root cap or adsorbed to root hairs. Cross sections of Azospirillum-inoculated roots showed prominent alterations of the cell arrangement in the layers of the cortex. The results suggest the existence of critical numbers of sites for Azospirillum colonization on the roots, to such an extent that root growth is affected.
Regulation of respiratory activity by oxygen in Arthrobacter fluorescens ammonium-limited chemostat culture
Authors: Cacciari I. , Lippi D. , Ippoliti S. , Pietrosanti T. , Pietrosanti W.
Published: May 2010

The effect of a sudden imposition of either oxygen limitation or over oxygenation on an Arthrobacter sp. ammonium-limited chemostat culture was studied at growth rate of 0.03 h−1. Growth and respiratory activity of the cultures were examined during the transition periods and at both steady-states. Arthrobacter fluorescens responded to oxygen limitation by increasing respiratory rate and degrading polysaccharide content. In contrast, an increase in dissolved oxygen concentration caused a decrease in respiration rate and an increase in biosynthesis of endogenous polysaccharides. Under both conditions an inverse relationship seemed to occur between respiration rate and yield coefficients.
Effects of different temperature regimes on microbial activity and biomass in composting municipal sewage sludge
Authors: McKinley Vicky L. , Vestal J. Robie
Published: May 2010

Municipal sewage sludge was composted under two different temperature regimes. The temperatures within the composting piles were regulated using a temperature feedback system controlling aeration fans which blew air up through the piles. Each composting run lasted about 2.5 weeks. In one part of the composting pile, the mean temperatures were kept below about 58 °C, while in the other part the mean temperatures reached 84 °C. Two experimental composting runs of this type were performed. In both cases the major treatment effect was the highly significant differences in microbial activity ([14C]acetate incorporation into lipids) per gram of compost or per unit of microbial biomass, with the low-temperature part of the piles having the greatest activity. Microbial biomass (measured as lipid phosphate) was greater in the low-temperature part of the pile by day 10 of the second composting run. The pH of the low-temperature piles also tended to increase more rapidly than that of the high-temperature piles. These results confirm other work in which increased rates of CO2 production were detected in materials composting at lower temperatures. It is suggested that the efficiency of batch composting processes is greatest at moderate temperatures (not exceeding about 55 °C), since higher temperatures greatly inhibit the growth and metabolism of the micro-biota.
Measuring the spermosphere colonizing capacity (spermosphere competence) of bacterial inoculants
Authors: Kloepper J. W. , Scher F. M. , Laliberté M. , Zaleska I.
Published: May 2010

Spermosphere establishment by bacteria which were coated onto seeds was studied using soybean seeds treated with four bacterial strains at levels of log10 1 to 4 colony-forming units (cfu) per seed planted in a field soil mix, and incubated 48 h. Each strain at every inoculum level developed spermosphere population densities of log10 4 to 8 cfu/seed, demonstrating an average multiplication of log10 3 cfu/seed. An alternative method was developed to differentially rank bacteria for spermosphere colonizing capacity, based upon incorporation of bacteria into a soil and monitoring the resulting spermosphere population densities around noninoculated seeds after 4 days at 14 °C. Fifty-seven bacterial strains which were isolated from soybean roots or from water samples, including Pseudomonas putida, P. putida biovarB, P. fluorescens, Serratia liquefaciens, Enterobacter aerogenes, and Bacillus spp. were tested in the spermosphere colonization assay. Average spermosphere population densities for the 57 strains ranged from 0 to log10 7.0 cfu/seed. Strains of a given taxon demonstrated marked diversity with ranges from 0 to log10 6.0 cfu/seed for Bacillus spp. and from log10 1.4 to 7.0 cfu/seed for Pseudomonas putida. The relative ranking of representative strains was consistent in repeating experiments. The potential usefulness of the assay for efforts to develop competitive bacterial inoculants for crop seeds is discussed.
An improved selection technique and medium for the isolation and enumeration of Azospirillum brasilense
Authors: Bashan Yoav , Levanony Hanna
Published: May 2010

An improved selection technique for isolation and enumeration of Azospirillum brasilense was developed. The technique is based on successive liquid enrichments in nitrogen-free semisolid medium supplemented with streptomycin, followed by the most probable number counting method and verification on a selective medium. The latter is based on Okon's nitrogen-free medium supplemented with cycloheximide (250 mg/L), streptomycin sulphate (200 mg/L), sodium deoxycholate (200 mg/L), 2,3,5-triphenyltetrazolium chloride (15 mg/L), and Congo red (1000 mg/L). This medium was found to be superior to other available diagnostic media. The technique was readily applied to detect and count A. brasilense Cd in inoculated wheat roots.
Scanning electron microscopy of the ontogeny of Ampelomyces quisqualis pycnidia
Authors: Galper S. , Sztejnberg A. , Lisker N.
Published: May 2010

Observations on Ampelomyces quisqualis disclosed that the pycnidium may originate either from one cell of a single pycnidiospore, or from one hyphal cell. In the first case the pycnidiospore becomes two celled and swollen and a profuse germination of one of the two swollen spore cells can be observed. Later, the short hyphae branches, interweave, and anastomose to form a compact network around the mother spore, the pycnidium primordium. Similarly, we observed profuse branching in a single hyphal cell. The newly formed branches interweave and anastomose to form a compact network which gives rise to the pycnidium primordium. Hyphal rings were also observed throughout this study, but no pycnidia arose from these structures. During the vegetative growth of the fungus, hyphal anastomosis seems to be a frequent pattern. It seems that the pycnidial ontogeny of A. quisqualis does not conform to any known developmental type.
Azospirillum–Rhizobium interaction leading to a plant growth stimulation without nodule formation
Authors: Plazinski Jacek , Rolfe Barry G.
Published: May 2010

The effect of inoculation of white clover plants with mixed cultures of Rhizobium trifolii strain ANU870 and Azospirillum brasilense strain SP245 was examined. Ratios of Rhizobium–Azospirillum (R:A) of 1:200 to 1:2500 caused an inhibition of nodulation. However, these nonnodulated plants did not show nitrogen-deficiency symptoms when grown on nitrogenfree medium. When these plants were assayed for acetylene reduction activity a low level of ethylene production was detected. A significant increase in plant dry weights was also observed. Isolation of viable bacterial cells from surface-sterilized root segments of plants inoculated with an R:A ratio of 1:200 revealed that 80% of the bacterial population was made up of the Azospirillum strain. Under laboratory conditions transfer of the Rhizobium Sym(biosis) plasmid pBRIAN to strain SP245 was observed ex planta. However, the Sym plasmid was unstable in Azospirillum. A high frequency of Tn5 transfer from pBRIAN to strain SP245 occurred when strains ANU870 and SP245 were mixed in the rhizosphere and (or) in the root tissue. Tn5 transposed preferentially into the smallest indigenous plasmid of strain SP245 and was easily lost when this strain (SP245::Tn5) was not maintained on selective medium. This mutated Azospirillum strain caused plant growth stimulation when inoculated onto white clover plants.
A comparative study of properties of chitin synthase from two Mortierella species
Authors: Adjimani J. P. , Manocha M. S.
Published: May 2010

Properties of chitin synthase obtained from mycelial homogenates of Mortierella pusilla and Mortierella candelabrum were compared. The enzyme was localized mainly in the mixed membrane fractions of both species. The reaction product, chitin, was characterized by its insolubility in weak acid and alkali and by the release of glucosamine and diacetylchitobiose on hydrolysis with strong acid and chitinase, respectively. Apparent Km values for UDP-N-acetyl-D-glucosamine (UDP-GlcNAc) were 1.8 mM and 2.0 mM for M. pusilla and M. candelabrum, respectively, and the inhibition constant, Ki, for polyoxin D was three orders of magnitude lower than the Km for UDP-GlcNAc. Enzyme preparations from both species were stimulated by Mg2+, Mn2+ or Co2+ and N-acetyl-glucosamine. Large differences in the ratio of active to inactive chitin synthase of the two species, were observed. Unlike M. candelabrum chitin synthase activity in the membrane fraction of M. pusilla increased during low temperature storage. The 100 000 × g supernatant fractions from cell-free extracts of M. candelabrum and M. pusilla were found to inhibit chitin synthase activity in both the fungi.
An inhibitor typing scheme applicable to Lancefield group E streptococci
Authors: Tagg John R.
Published: May 2010

A previously described inhibitor typing scheme for hemolytic streptococci has been utilized to test 12 well-characterized strains of group E streptococci. These strains were differentiated into five inhibitor production (P) types and four inhibitor sensitivity (S) types: seven different strain "fingerprints" (combinations of P-type and S-type) being demonstrated. Inhibitor production by group E streptococci was increased under conditions of anaerobic incubation. The inhibitor fingerprints were stable on repeated testing of strains and it is suggested that the scheme is of value both for the labelling of serologically untypable strains and for subdividing strains belonging to existing serotypes.
Deoxyribonucleic acids of Corynebacterium genitalium and Corynebacterium pseudogenitalium: their genome molecular weights, base ratios, and DNA relatedness with other corynebacteria involved in urinary tract infections
Authors: Imaeda T. , Coppola K. M. , Furness G.
Published: May 2010

Chromosomal deoxyribonucleic acids of Corynebacterium genitalium and Corynebacterium pseudogenitalium were isolated and analysed spectrophotometrically. Their genome molecular weights ranged from 1.1 × 109 to 1.6 × 109. The guanine-plus-cytosine content of C. genitalium ranged from 60.0 to 63.3%, whereas that of C. pseudogenitalium ranged from 56.1 to 58.7%. Five strains of C. genitalium showed relatively low levels of DNA relatedness to each other ranging from 35 to 64%. In contrast, most strains of C. pseudogenitalium showed high levels of DNA relatedness to each other ranging from 71 to 89%. Selected strains of C. genitalium and C. pseudogenitalium showed low levels of DNA relatedness (49 to 60%) to other corynebacterial species involved in urinary tract infection. Data obtained in this study indicate that all strains of C. genitalium consist of genetically divergent organisms while the most strains of C. pseudogenitalium belong to a single species.
Purification and characterization of the protease inhibitor "monastatin" from a marine Alteromonas sp. with reference to inhibition of the protease produced by a bacterium pathogenic to fish
Authors: Imada Chiaki , Maeda Masachika , Taga Nobuo
Published: May 2010

A novel protease inhibitor, which we named "monastatin," produced by a marine bacterium was purified using ammonium sulfate precipitation, DEAE-cellulofine column chromatography, and gel filtration through Sephadex G-100. Monastatin was purified to homogeneity, as a single staining band in polyacrylamide gel electrophoresis. Monastatin was a glycoprotein with a molecular weight of about 20 000. It was stable up to 100 °C for a 30-min incubation with loss of 20% of inhibitory activity and also showed stability over a wide range of pH from 2 to 12. Metal ions such as Cu2+ and Fe2+ repressed the inhibitory activity to 0%. Monastatin had an inhibitory activity against thiol proteases such as papain and ficin.
Determination of phospholipid ester-linked fatty acids and poly β-hydroxybutyrate for the estimation of bacterial biomass and activity in the rhizosphere of the rape plant Brassica napus (L.)
Authors: Tunlid Anders , Baird Bruce H. , Trexler Melanie B. , Olsson Stefan , Findlay Robert H. , Odham Goran , White David C.
Published: May 2010

Examination of seven strains of gram-negative bacteria isolated from the rhizosphere of the rape plant showed profiles of fatty acids, ester-linked to their phospholipids that were distinctly different from sterile roots. The bacteria were enriched in short and branched saturated, cyclopropane and monoenoic fatty acids in which the unsaturation was formed by the anerobic desaturase pathway when growth was on a medium simulating root exudates. This suite of fatty acids was significantly increased in sand and in roots of rape plants grown from seeds in sands inoculated with these organisms at the start of the experiments. Some of the bacteria formed the endogenous storage polymer poly β-hydroxybutyrate in monocultures. Poly β-hydroxybutyrate was formed by the bacteria in the inoculated sand in large amounts but not by the bacteria that were recovered from the roots. This suggests that bacteria associated with the roots were in balanced growth, whereas the bacteria in the sand were lacking essential nutrients and showed an unbalanced growth response. These chemical analyses provided estimates of the bacterial biomass (from the sum of bacterial ester-linked phospholipid fatty acids) and the metabolic status (poly β-hydroxybutyrate to phospholipid fatty acid ratio) in this experiment. With further definition of lipid biomarkers of soil microorganisms these experimental techniques may be extended to the rhizosphere.
Distribution of sterols in fungi. II. Brassicasterol in Tuber and Terfezia species
Authors: Weete J. D. , Kulifaj M. , Montant C. , Nes W. R. , Sancholle M.
Published: May 2010

Sterols from ascocarps of Tuber (truffle) and Terfezia species were identified by gas–liquid chromatography, gas chromatography – mass spectrometry, and 1H nuclear magnetic resonance, and the structure of brassicasterol from the yeastlike cells of Taphrina deformans confirmed by 1H nuclear magnetic resonance. Sterols of the fruiting bodies ranged from 1.2 to 2.3 μg/mg dry weight. Ergosterol was the principal sterol of Tuber species which also contained 28–44% brassicasterol depending on the species and source of the sample. Terfezia sp., on the other hand, contained about 98% brassicasterol with only small amounts of ergosterol. Brassicasterol is common to several families of the subdivision Ascomycotina, and to our knowledge has not been reported for a nonascomycetous species.
Spotted fever group rickettsiae in immature and adult ticks (Acari: Ixodidae) from a focus of Rocky Mountain spotted fever in Connecticut
Authors: Magnarelli Louis A. , Anderson John F. , Burgdorfer Willy , Philip Robert N. , Chappell W. Adrian
Published: May 2010

Immature and adult ixodid ticks were collected during 1983 and 1984 in Newtown, Connecticut, an area endemic for Rocky Mountain spotted fever (RMSF), to determine prevalence of infection by spotted fever group (SFG) rickettsiae. Direct fluorescent-antibody (FA) staining revealed SFG organisms in 6 (1.8%) of 332 Dermacentor variabilis larvae, 5 (7.8%) of 64 D. variabilis nymphs, and in 2 (40%) of 5 Ixodes cookei nymphs removed from small- and medium-sized mammals. Hemolymph tests detected rickettsia-like organisms in 15 (8.8%) of 170 D. variabilis adults; 8 specimens retested by direct FA were negative. In contrast, hemocytes from 5 (8.6%) of 58 Ixodes texanus females contained organisms that stained positively in both hemolymph and direct FA tests. An indirect microimmunofluorescence test identified specific antibodies to Rickettsia rickettsii, the etiologic agent of RMSF, in serum samples from a chipmunk, raccoons, and white-footed mice. Results indicate that immature or adult ticks of at least three species may be involved in the maintenance and transmission of SFG rickettsiae at Newtown.
Denitrification by a diazotrophic Pseudomonas species
Authors: Chan Yiu-Kwok
Published: May 2010

Pseudomonas sp. type strain H8 is a N2-fixing H2-utilizing bacterium frequently isolated from the root of wetland rice. It was previously reported not to denitrify although [Formula: see text] was reduced to [Formula: see text]. In the present study it grew anaerobically with [Formula: see text], [Formula: see text], or N2O as electron acceptor. Its capability to denitrify was confirmed by using the C2H2-inhibition technique in both undefined and defined media with glucose as carbon source. Chemolithotrophic denitrification of [Formula: see text] with H2 and CO2 was also demonstrated. Its H2-uptake activity was found to be higher when grown initially in the presence of 10% O2 than 21% O2 or 5 mM[Formula: see text] Compared with Azospirillum brasilense, a N2-fixing bacterium capable of denitrification, H8 was not sensitive to [Formula: see text] toxicity under similar experimental conditions. Preliminary evidence suggested that N2O reduction by H8, but not by A. brasilense, was inhibited by yeast extract. The denitrification capability of H8 may prove to be an undesirable characteristic that leads to the removal of [Formula: see text] N from soils.
Immune immobilization of Treponema pallidum: antibody and complement interactions revisited
Authors: Rice Marianne , Fitzgerald T. J.
Published: May 2010

The Treponema pallidum immobilization test was designed for serodiagnosis of syphilis and is dependent upon specific antibody and a heat labile component of normal serum. Investigators have shown the component to be dependent upon divalent cations and it is presumed to be complement. Experiments were performed to reevaluate the interactions of antibody and complement and the mechanism of immobilization. The loss of treponemal motility was correlated to the loss of complement activity in the reaction mixture. When motility of treponemes incubated with immune serum IgG and complement had dropped to 50% (3.4 h), 72% of the available complement had been consumed. At the same time, treponemes incubated with normal serum IgG and complement were 82% motile and only 51% of the complement had been consumed. C6 deficient rabbit serum and C4 deficient guinea pig serum were used in conjunction with immune serum IgG to determine which components of the complement cascade were necessary for immobilization. Treponemes were not immobilized by either sera. Results suggest that the heat labile factor in normal sera is complement, that both early and late components of the complement cascade are necessary, and that the reaction proceeds via the classical complement pathway. Although T. pallidum is susceptible to the actions of antibody and complement, the organisms must interact with these components for at least 2 h before immobilization will result.
Bacterial control of Agromyces ramosus in soil
Authors: Byrd Jeffrey J. , Zeph Lawrence R. , Casida Jr. L. E.
Published: May 2010

Agromyces ramosus occurs in high numbers in many soils. It also is a known predator of various gram-positive and gram-negative soil bacteria, including Azotobacter vinelandii. Based on this, it would seem that, in natural soil, A. ramosus should control the population sizes of these soil bacteria. As a partial test of this assumption, we examined the possibility that soil might contain other bacterial predators that could hold A. ramosus in check. Three gram-negative bacterial predators of A. ramosus were isolated from soil. When one of these predators, strain N-1, was added to natural soil, it exhibited an attack – counter attack phenomenon in its interactions with A. ramosus. The indigenous A. ramosus cells in soil, or added A. ramosus cells, produced mycelium that approached, then lysed, approximately one-third of the N-1 cells. The surviving N-1 cells, however, then proceeded to lyse the A. ramosus mycelium, but not the rod-form cells that had fragmented from the mycelium. Strain N-1 then multiplied. This sequence also occurred if Azotobacter vinelandii was added with A. ramosus to soil, either with or without addition of N-1 cells. N-1 attacked the A. ramosus mycelium that was attacking Azotobacter vinelandii. In soil and with pure cultures in the laboratory, the dormant rod-form cells of A. ramosus that fragmented from the mycelium were not attacked. A growth initiation factor seemed to be involved in the attack – counter attack relationship of N-1 and A. ramosus. Strain N-1 and the other two gram-negative predators mentioned above could attack a variety of bacterial species in soil, in addition to A. ramosus which in itself is a predator. Thus, some sort of hierarchy of bacterial predation seems to exist in soil.
Fluorometric determination of the total DNA content of different yeast species using 4′, 6-diamidino-2-phenyl-indol-dihydrochloride
Authors: Leusch H. G. , Hoffmann M. , Emeis C. C.
Published: May 2010

A highly sensitive method has been developed to measure quantitatively the DNA content of yeast cells. The reaction between the fluorescent dye 4′, 6-diamidino-2-phenyl-indol-dihydrochloride and DNA in a crude lysate from protoplasts can be measured without prior extraction of the DNA. Interferences by the high protein and RNA content of yeast cells, which often limit the accuracy of common methods employed in the determination of DNA content, were eliminated by suitable enzymatic pretreatment of the cell lysate.
Sequential appearance of radiolabel-tagged cyclohexadienyl derivatives of shikimate in Neurospora
Authors: Zamir Lolita O. , Devor Kenneth A.
Published: May 2010

The growing interest in the arogenate molecule and its derivatives in applied plant biochemistry stems from its regulation of the first enzyme in the aromatic pathway. The recent finding of a new derivative of arogenate (spiro-arogenate) in a mutant of Neurospora crassa raised the question of the biosynthetic sequence of cyclohexadienyl shikimate derived metabolites. Specifically labeled tritiated shikimate was used as a tracer. We have observed the uptake and metabolism of shikimate by this mutant. We have also demonstrated conclusively in vivo that arogenate appears prior to spiro-arogenate in this strain. The levels of accumulation of the various nonaromatic shikimate metabolites were determined in the cells. Intracellular arogenate levels exceeded prephenate levels which is exactly the opposite of results obtained in the culture supernate.
Endo-1, 4-β-glucanase and β-glucosidase of the ciliate Polyplastron multivesiculatum free of cellulolytic bacteria
Authors: Bonhomme A. , Fonty G. , Foglietti M. J. , Robic D. , Weber M.
Published: May 2010

To determine the contribution of protozoal activity to cellulose degradation, we maintained the ciliate Polyplastron multivesiculatum free of extracellular and intracellular cellulolytic bacteria. Control experiments to verify the absence of such bacteria were performed on cellular extracts, on filtrates, and on ciliates before lyophilization. The enzymatic activity was determined by viscometry and by determining the amount of reducing sugars produced. The enzyme was found to be an endo-1, 4- β-glucanase. Polyplastron multivesiculatum which was maintained free of extracellular and intracellular bacteria degraded soluble derivatives of cellulose and slightly degraded native cellulose. The activity was not due to intracellular bacterial cellulase, as ingested bacteria were lysed and digested by proteolytic enzymes of the protozoan. In addition, when preparing the filtrate solutions, P. multivesiculatum was maintained in culture for 5 days with Streptococcus faecalis (a facultatively anaerobic, noncellulolytic bacterium). Isoelectric focusing and chromatofocusing of lyophilized P. multivesiculatum that was free of cellulolytic bacteria yielded three protein fractions that degrade carboxymethylcellulose and hydroxyethylcellulose. Chromatofocusing also revealed the presence of two protein fractions with β-glucosidase activity.
Manganese and antibiotic biosynthesis. II. Cellular levels of manganese during the transition to patulin production in Penicillium urticae
Authors: Scott R. E. , Gaucher G. M.
Published: May 2010

The radionuclide 54MnCl2 was used to examine the cellular manganese content of submerged cultures of Penicillium urticae NRRL 2159A. Liquid-scintillation spectroscopy allowed sensitive detection of isotopic manganese in both normally supplemented and manganese-deficient cultures. The cellular manganese content in supplemented cultures showed three distinct phases, including a period of uptake that coincided with the time of transition to antibiotic biosynthesis. Such an uptake was not seen for manganese-deficient cultures, but addition of normal quantities of unlabelled manganese to the media appeared to stimulate uptake. Preliminary characterization shows this manganese uptake is not inhibited by other metal ions, does not require metabolic energy or a protein component, but is disrupted by changes in incubation temperature. The significance of these observations is discussed in the light of recent work on the requirement for manganese for antibiotic biosynthesis in this organism.
A quantitative comparison of microbial community structure of estuarine sediments from microcosms and the field
Authors: Federle Thomas W. , Livingston Robert J. , Wolfe Loretta E. , White David C.
Published: May 2010

Estuarine soft-bottom sediments in microcosms and the field were compared with regard to microbial community structure. Community structure was determined by analyzing the fatty acids derived from the microbial lipids in the sediments. Fatty acid profiles were compared using a multivariate statistical approach. Experiments were performed using sediments from St. George Sound and Apalachicola Bay, Florida. The community structure of St. George Sound sediments was apparently controlled by epibenthic predators. In Apalachicola Bay, the dominant influences were physical factors related to the flow of the Apalachicola River. In the St. George Sound experiment, microbial communities in the microcosms differed from those in the field after only 2 weeks, and the degree of this difference increased substantially as time progressed. In the Apalachicola Bay experiment, although microbial communities in the microcosms were detectably different from those in the field, the degree of this difference was not large nor did it increase with time. This differential behavior of sediment communities from different sites may be related to the different ecological factors regulating community composition at these sites.
Purification and characterization of kynurenine formamidase activities from Streptomyces parvulus
Authors: Brown Dale , Hitchcock Michael J. M. , Katz Edward
Published: May 2010

Two forms of kynurenine formamidase (EC 3.5.1.9; aryl-formylamine amidohydrolase) are present in extracts of Streptomyces parvulus. The higher molecular weight enzyme (Mr = 42 000), kynurenine formamidase I, appears to be constitutive and is present at relatively constant but low levels in antibiotic producing and nonproducing cultures, whereas the synthesis of the lower molecular weight form (Mr = 25 000), kynurenine formamidase II, is initiated just prior to the onset of actinomycin formation. It is postulated (i) that kynurenine formamidase II catalyzes the second step in the pathway from tryptophan → actinocin, and (ii) that it is regulated specifically for the specialized function of actinomycin biosynthesis. The role of kynurenine formamidase I is unknown. Formamidase I and II activities were purified from extracts of S. parvulus and kinetic parameters of the two enzymes were determined. Although some of the properties of the two enzymes are quite similar (substrate specificities, Km values), some striking differences were noted (pH and temperature optima, molecular size, chromatographic properties, sensitivity to certain ions and chemicals). Mutant studies suggest that expression of the gene(s) coding for formamidase II activity play an essential role in regulating the formation of actinocin and, hence, antibiotic synthesis. Kynurenine formamidase activity was also found in a representative number of Streptomyces species and related organisms suggesting that the enzyme may function in the degradative metabolism of tryptophan by certain actinomycetes in nature.