bluuebunny/crossref_metadata_2025 huggingface dataset:
Bindings of plasma proteins to streptococci of serological group L with special reference to their immunoglobulin G Fc-receptor activity
Authors: Lämmler C. , Schaufuß P. , Frede C. , Blobel H.
Published: May 2010

Of 33 streptococcal cultures belonging to serological group L, all bound human immunoglobulin (Ig) G, fibrinogen, and fibronectin; 32 bound bovine IgG; 31 bound α2-macroglobulin; 5 bound albumin; and none bound either haptoglobin or IgA. The binding sites for IgG could be isolated from the L streptococci by trypsinization and purified by affinity chromatography on human IgG – Sepharose®. The purified Fc receptors reacted with IgG subclasses 1, 2, 3, 4 of humans, 1 and 2 of bovines, ovines, and caprines as well as a, b, c, and T of equines. They had a molecular mass of approximately 49 000 Da. Thus, the Fc receptors from L streptococci corresponded to type III Fc receptors of Streptococcus dysgalactiae.
Monoclonal antibodies against the maize bushy stunt agent
Authors: Chen T. A. , Jiang X. F.
Published: May 2010

Monoclonal antibodies against a mycoplasmalike organism that causes maize bushy stunt disease were produced by using partially purified preparations from infected corn plants as immunogen. Splenic cells from immunized mice were fused with P3/NS-1/1-Ag4-1 murine myeloma cells. Four stable hybridoma clones that secreted specific antibodies against the maize bushy stunt mycoplasmalike organism were selected from several thousand clones. The monoclonal antibodies were isotyped and determined to belong to immunoglobulin classes IgM and IgG2a. With these monoclonal antibodies, the maize bushy stunt mycoplasmalike organism was specifically identified from infected corn tissue by enzyme-linked immunosorbent assay in vitro and by immunofluorescent staining in situ. Mycoplasmalike organisms associated with aster yellows (New Jersey strain), clover phyllody, eastern X disease, elm yellows, paulownia witches'-broom, and sweet potato witches'-broom were differentiated from maize bushy stunt agent by serology using these monoclonal antibodies. Monoclonal antibodies specific to maize bushy stunt mycoplasmalike organism also did not react with two plant pathogenic spiroplasmas: Spiroplasma kunkelii and Spiroplasma citri.
Mutual antagonism among killer yeasts: competition between Kl and K2 killers and a novel cDNA-based K1-K2 killer strain of Saccharomyces cerevisiae
Authors: Bussey Howard , Vernet Thierry , Sdicu Anne-Marie
Published: May 2010

Mutually antagonistic K1 and K2 killer strains compete when mixed and serially subcultured. At pH 4.6, where the K1 killer toxin is more stable in vitro, the K1 strain outcompeted the K2 strains at both 18 and 30 °C. At pH 4.0, closer to the in vitro pH optimum of the K2 killer toxin, the K1 strain again predominated at 18 °C, but at 30 °C the K2 strains became the sole cell type on subculture. To show more clearly that these results were dependent upon the respective killer toxins, control experiments were conducted with isogenic, nonkiller strains cured of the dsRNA-based killer virions. Such nonkiller strains were unable to compete with antagonistic killers under conditions where their isogenic killer parents could, strongly suggesting that the killer phenotype was important in these competitions. Double K1–K2 killer strains cannot stably exist, as their dsRNA genomes compete at a replicative level. Using recombinant DNA methodology, a stable K1–K2 killer strain was constructed. This strain outcompeted both K1 and K2 killers when serially subcultured under conditions where either the K1 or the K2 strains would normally predominate in mixed cultures. Such a double killer may be useful in commercial fermentations, where there is a risk of contamination by killer yeasts.
The stability of O-antigen plasmid is determined by a chromosomal region of Shigella dysenteriae
Authors: Aqua Mfon S. , Svinarich David , Dhar Anju , Palchaudhuri Sunil
Published: May 2010

It is well established that plasmids are involved in the expression of lipopolysaccharide in certain species of Shigella. In Shigella sonnei, both the biosynthesis of oligosaccharide side chains (O antigen), and cell invasiveness are controlled exclusively by a 120 megadalton (MDa) plasmid. In Shigella dysenteriae 1, a 10 kilobase (kb) plasmid is required for O-antigen production. Shigella dysenteriae 1 strains devoid of this plasmid lose the ability to synthesize O antigen. Interestingly, this 10-kb plasmid is not stably maintained in Escherichia coli K-12 strains, where it is lost spontaneously at a high frequency. Our genetic analyses of Shigella dysenteriae 1 strain IDBM11 and its derivatives indicate that the stability of this plasmid is associated with the histidine region of the chromosome which is unique to Shigella dysenteriae. Furthermore, the 10-kb plasmid is stably maintained in wild-type IDBM11 with an intact histidine locus. However, this plasmid is not stable in IDBM11 derivatives (e.g., IDBM11-1 and IDBM11-2), in which the his locus has been substituted with the histidine region of an E. coli K-12 chromosome. The S. dysenteriae IDBM11 strain, and its derivatives (lacking a 10-kb plasmid), displayed an invasive property as demonstrated by their internalization by HeLa cells in an in vitro assay. Thus the 10-kb plasmid of Shigella dysenteriae 1 is required for O-antigen synthesis but not for cell invasion.
Migratory birds of central Washington as reservoirs of Campylobacter jejuni
Authors: Pacha R. E. , Clark G. W. , Williams E. A. , Carter A. M.
Published: May 2010

Migratory ducks, Canada geese, and sandhill crane from the Pacific North American Flyway have been screened for Campylobacter spp. Samples (298) from these birds were examined and the incidence of Campylobacter spp. in the samples were as follows: sandhill crane (Grus canadensis tabida), 81 %; ducks (Aythya collaris, Anas carolinensis, Aythya americana, and Anas platyrhynchos), 73%; and Canada geese (Branta canadensis), 5%. All isolates were identified as Campylobacter jejuni. To our knowledge this is the first report of the isolation of C. jejuni from sandhill crane. The high frequency of isolation in both the sandhill crane and migratory ducks indicated that these bird populations may play a significant role in the dissemination of the bacterium. Because of their migratory habits, these birds may be particularly important in spreading C. jejuni to remote areas.
Further characterization of Escherichia coli O153:H45, an ETEC serotype disseminated in Chile
Authors: Fernández-Beroš M. Elena , Kissel Vincent , Agüero Maria E. , Figueroa Guillermo , D'Ottone Karen , Prado Valeria , Cabello Felipe
Published: May 2010

The newly described stable enterotoxin producing, enterotoxigenic Escherichia coli, serotype O153:H45, capable of expressing colonizing factor antigen I, is frequently isolated as a cause of diarrhea among Chilean children. Hybridization studies of five new strains confirmed previous results which indicated that the stable enterotoxin genes are contained in nonconjugative plasmids ranging in size from 81 to 87 kilobases. The strains expressed similar antibiotic resistance and metabolic properties but differed in their plasmid content.
Production and use of monoclonal antibodies for identification of Bradyrhizobium japonicum strains
Authors: Velez D. , Macmillan J. D. , Miller L.
Published: May 2010

Thirteen murine hybridomas capable of producing monoclonal antibodies to somatic antigens on Bradyrhizobium japonicum were developed and an indirect enzyme-linked immunosorbent assay was used to test reactivity of the antibodies against 20 strains of B. japonicum. Although polyclonal antisera from mice immunized with strains of B. japonicum reacted with bacterial cells of all 20 strains, individual monoclonals were more specific. Some antibodies reacted with as few as 2 and one with as many as 11 strains. On the basis of reactivity with the set of 13 monoclonal antibodies, the 20 strains of B. japonicum could be divided arbitrarily into five groups. Three of five monoclonal antibodies tested reacted with bacteroids taken directly from soybean nodules. One monoclonal bound to cells of five species of Rhizobium, but none of the 13 reacted with gram-negative bacteria representing six other genera. Treatment of cells with reagents and heat indicated the chemical nature of the antigens to five of the monoclonals. Antigen reactive with one antibody was destroyed by periodate oxidation indicating that it was a polysaccharide. Two antigens were probably proteins as they could be digested by trypsin and denatured by heat. Two others were inactivated by all three treatments suggesting they were glycoproteins.
Effects of processing on peat moss microflora
Authors: Cormier Yvon , Mériaux Anne , Brochu Gilles
Published: May 2010

We studied the microflora of Quebec sphagnum peat moss samples taken from five different locations in a peat moss processing plant: soil, drying stacks, sedimented dust (walls and floor), and in bagged peat moss. Large numbers of microorganisms were found; the predominant ones were of the genus Monocillium (up to 112 × 106 colonies/g of dry peat) and the genus Penicillium (320 × 104 colonies/g dry weight). These moulds were more abundant in the processed peat moss than in the peat soil (e.g., Monocillium: soil, 138 × 103; processed peat, 112 × 106). Aspergillus spp. were absent in all five sample sites. We conclude that Quebec peat moss contains large quantities of microorganisms and that moulds become more concentrated during the processing of the peat from the soil to the final product.
Composition and ultrastructure of the sporangiospore wall of Rhizopus stolonifer
Authors: Diaz-Torres Maria R. , Claverie-Martin Felix , Geoghegan Michael J.
Published: May 2010

The chemical composition and ultrastructure of the cell wall of Rhizopus stolonifer sporangiospores were determined. Spores were examined by transmission electron microscopy using both thin sections and surface replicas, and by scanning electron microscopy. The spore wall was found to be composed of three layers: (i) a ridged electron-opaque outer layer (10–240 nm thick) occasionally covered by a very thin extra layer; (ii) an electron-transparent layer containing electron-dense areas (160–245 nm thick); and (iii) an innermost layer of relatively high electron density overlaying the plasma membrane (15–40 nm thick). The spore wall had a rough amorphous surface without rodlet fascicles. Chemical analysis showed that the major components were protein, glucan, chitosan, and melanin, followed by smaller amounts of uronic acids, lipids, chitin, and mannose. The protein(s) contained high levels of aspartic acid and glutamic acid, followed by glycine, alanine, lysine, histidine, serine, and by smaller amounts of other amino acids. Melanin was intimately associated with protein and glucosamine.
Transduction of Escherichia coli in soil
Authors: Germida James J. , Khachatourians George G.
Published: May 2010

Bacteriophage P1-mediated generalized transduction of Escherichia coli K-12 was assessed in nonsterile soil. Auxotrophic recipient cells (thr−leu−thi−rpsL) were incubated in a sandy and a silty clay loam soil, and the transducing phage lysates from prototrophic strains carrying transposon 10 (Tn10) in either purE or aroL regions were added. At intervals, the bacterial populations derived from the soils were plated on selective-differential media to enumerate prototrophic (thr+, leu+, or Tcr) transductants. Of 100 bacterial isolates obtained on the selective-differential media, 58 (14 thr+; 11, leu+; 33 Tcr) were confirmed E. coli transductants. The frequency of transduction in soil was ca. 10−6. These data demonstrate the potential use of bacteriophage P1 to genetically manipulate E. coli in situ.
Developmental effects of the major ions found in a groundwater sample on sexual cultures of Dictyostelium discoideum
Authors: Lydan Michael A. , O'Day Danton H.
Published: May 2010

Addition of 25 ppm magnesium, 40 ppm nitrate, 140 ppm sulphate, and 170 ppm chloride to mixed mating type cultures of Dictyostelium discoideum was found to both markedly increase the peak number and cause an earlier developmental age of appearance of binucleate and zygote giant cells over similar cultures made without the ions. Peak cell fusion values were enhanced by about 20% in ion-supplemented cultures. Developmental kinetics in separate cultures made with each component ion showed that the enhancement of cell type percentages and total cell fusion required the combined action of at least two of the ions. Lactose (0.1 %) – proteose peptone no. 3 (0.1%) liquid culture medium supplemented with the above ions yields a medium which maximizes cell fusion, facilitating its study during sexual development in D. discoideum.
Characterization of Azospirilla isolated from seeds and roots of turf grass
Authors: Sundaram Subramaniam , Arunakumari Alahari , Klucas Robert V.
Published: May 2010

Nitrogen-fixing bacteria were isolated from surface-sterilized seeds and roots of turf grasses growing in Nebraska. The percentage of successful isolations from surface-sterilized seeds ranged from 0 to 100 depending upon the source of the seeds. Based upon morphological and physiological characterization, some of the root and seed isolates appeared to be Azospirillum spp. Deoxyribonucleic acid homology studies on four selected isolates indicated that two root and one seed isolates were related to Azospirillum brasilense SP-7 with 70% or greater DNA homology, and one seed isolate was related to reference strain Azospirillum amazonense Y1 with 100% DNA homology. After repeated culturing on semisolid malate medium, some of the isolates lost their capacity to fix nitrogen. However, when certain non-nitrogen-fixing isolates were used as inoculants on turf grasses grown from surface-sterilized seeds which possessed no detectable indigenous nitrogen-fixing bacteria, nitrogenase activity as measured by acetylene reduction was detected.
Controlled lysis of bacterial cells utilizing mutants with defective synthesis of D-alanine
Authors: Heaton Michael P. , Johnston Robert B. , Thompson Thomas L.
Published: May 2010

An alanine racemase (EC 5.1.1.1) mutant (Dal−) of Bacillus subtilis required small amounts of D-alanine to synthesize an osmotically stable cell wall in certain growth media. Investigation of the conditions which caused lysis in hypotonic media revealed that in addition to complex media, such as nutrient broth and acid-hydrolyzed casein, glycine inhibited stable cell wall formation. D-Alanine prevented the glycine inhibition. Up to 99% lysis occurred in both dilute and dense cell suspensions (optical densities up to 110) within 2.5 h after adding 1% glycine to late log phase cultures. Intracellular enzymes recovered from the lysate were as active as those from lysozyme-disrupted cells. No amino acid tested other than glycine induced lysis. Dal− mutants can be used for controlled lysis of bacterial cells to facilitate the isolation of normal intracellular constituents and bioengineered products from fermentation processes. Cell walls of most bacteria contain D-alanine; thus, this strategy should be applicable to a wide variety of microorganisms.
Wound fiberglass depth filters as a less expensive approach for the concentration of viruses from water
Authors: Payment Pierre , Trudel Michel
Published: May 2010

Wound fiberglass depth cartridge filters (25.4 cm) with a nominal porosity of 1 μm were used to concentrate viruses from large volumes of surface water. They were found to be an excellent, less expensive alternative to the 0.2-μm pleated cartridge filters normally used for the concentration of enteric viruses from water. More than 99% of experimentally seeded poliovirus was adsorbed to these filters when the pH of the water was adjusted to pH 3.5 and aluminium chloride was added to a final concentration of 0.001 M, as recommended for electronegative filters. In comparative recovery of indigenous viruses from river water, similar results were obtained with two 1-μm or a 3-μm + 0.2-μm filter combination. The cost of the two 1-μm filters is about Can. $26, while it is about Can. $58 for the other combination.
INTRODUCTION
Authors: Reid Gregor , Bruce Andrew W.
Published: May 2010

The Lister Symposium was held primarily to review the latest concepts of the mechanisms of bacterial infections, and to highlight the research being carried out currently in Toronto and in Canada. The inclusion of several speakers from outside of Toronto added a strong foundation for the meeting.A wide range of topics were addressed and these demonstrated the many areas of research being pursued to better understand the pathogenesis of microbial infections. By drawing together physicians, scientists, and students from a variety of disciplines, it was hoped that the Lister Symposium would contribute, not only to our knowledge of medicine and science in this field, but also to the continued local and national cooperation required for first-class investigative research.This meeting was the first of its kind held under the auspices of the Department of Surgery at the University of Toronto, demonstrating its commitment to research and interdepartmental collaboration. We are most grateful to Professor Bernard Langer, Chairman of the Department of Surgery, for his support in this regard. The assistance of our sponsors and the Continuing Medical Education Office facilitated a wide outreach and enabled recognition of the course and accreditation for Canadian and American Medical participants. It is hoped that this material will provide a useful reference for future developments in the field.
Immunogenetic aspects of host immune response
Authors: Inman R. D.
Published: May 2010

The central role of histocompatibility leukocyte antigens (HLA) class II molecules in antigen presentation has received great attention in recent years, yet class I molecules have been defined as primarily functioning as a restriction element for cytotoxic T cell killing of virus-infected cells. Extensive clinical evidence, however, indicates that the HLA class I genes are strongly associated with nonseptic complications of enteric and genitourinary bacterial infections. Ninety percent of patients with Reiter's syndrome and reactive arthritis are positive for HLA-B27, yet the mechanism of disease susceptibility conferred by this gene remains obscure. Hypotheses concerning this interaction include (i) class I antigens functioning as receptors for microbial antigens; (ii) class I antigens expressing determinants that cross-react with microbial antigens; and (iii) class I genes controlling immunoregulatory functions that dictate qualitative differences in immune response to pathogenic organisms. These hypotheses await formal testing and hold great promise for understanding immunogenetic control of immune responses in general.
The use of bacterial interference to prevent infection
Authors: Sprunt Katherine , Leidy Grace
Published: May 2010

For decades, bacterial strains of low virulence were occasionally used in man to replace or to block colonization by the more virulent organisms and thereby prevent bacterial infection. This paper reviews the topic and presents recent information on the implantation of strain 215 α-hemolytic streptococcus (α-strep) in the nasopharynx of neonates in the intensive care unit. A single inoculation of strain 215 can change abnormal colonization of the pharynx to "normal" (α-strep predominant) in 48–72 h in most neonates. Following implantation, α-strep with strain 215 like characteristics fluctuate among naturally occurring strains of α-strep, sometimes persisting in dominance and sometimes decreasing rapidly as new strains appear. Strain 215 can survive in the pharynx during subsequent antibiotic therapy and can be recalled to dominance by such therapy. It seems remarkably stable in vivo. There is no evidence of its nosocomial spread in the nursery. Streptococcus with strain 215 like characteristics occurred naturally in 1–6% of neonates in our intensive care unit. No infection (disease) attributable to strain 215 occurred in implanted infants.
Intravaginal instillation of lactobacilli for prevention of recurrent urinary tract infections
Authors: Bruce Andrew W. , Reid Gregor
Published: May 2010

Urinary tract infections remain a common problem, particularly in the female population. New methods are required to manage recurrent cystitis, and extensive research to date has suggested that restoration of the lactobacilli flora of the urogenital tract may prevent these infections. In this study, five females suffering from recurrent urinary tract infections were treated twice weekly with intravaginal and perineal implantation of Lactobacillus casei GR-1. These organisms colonized the epithelium and prevented the emergence of coliform bacteria in most instances, but did not appear to affect enterococcal colonization. In vitro studies showed that L. casei GR-1 inhibited the growth of the coliforms but did not inhibit enterococci. Each of the five patients had infection-free periods ranging from 4 weeks to 6 months. The treatment was well tolerated, had no side effects, led to an improved well-being, and was preferred to antibiotic treatment by all of the patients. These human studies, albeit of a limited nature, are the first to examine the potential for lactobacillus therapy in the prevention of urinary tract infections. The results show that lactobacilli therapy, using carefully selected organisms to treat patients who are closely followed, may be effective in the prevention of recurrent urinary tract infections.
Speculations on the growth strategy of prosthecate bacteria
Authors: Koch Arthur L.
Published: May 2010

Appendaged bacteria with stalks that are extensions of the cell wall have had to solve the problems of growing the stalk as a tube of constant diameter and of partitioning their chromosomes into the asymmetric daughter cells. Although no experimental proof is given, it is suggested that both processes depend on the attachment of the chromosome origin and terminus to the wall at special terminal sites that contain the basal body (motor assembly) for flagellar motion.
The domains of slow bacterial growth
Authors: Chesbro William
Published: May 2010

Commonly used culture systems, e.g., batch culture and the chemostat, work poorly for defining the behavior of slowly growing bacteria, i.e., cultures with mass doubling times, tD, longer than 10-12 h. This has slowed the process of understanding how bacteria behave at the longer tD's that embrace most of their existence. Culture systems are identified that give useful access to these longer doubling times. When these slow-growth systems are used with nutrient-limited populations, it is found that cellular concentrations of guanosine 5′ -diphosphate 3′ -diphosphate, the main effector of the stringent response, commence rising above basal levels at tD's longer than 12 h until, at a tD of 60–70 h, the level is reached that causes the interdiction of protein and ribosome synthesis characteristic of the response. The abrupt onset of the stringent response in eubacteria at a particular tD, corresponding to a specific rate of nutrient uptake, makes oft-used growth equations that do not account for this onset, e.g., those of Monod or Pirt, poor descriptors of slow growth. A serious imbalance between lateral and transverse wall formation rates which, unless corrected, would lead to abnormal cell division can be inferred to develop at tD's longer than 10–12 h. The necessary correction may be supplied by the effects of increased levels of guanosine 5′ -diphosphate 3′ -diphosphate on transverse wall synthesis.
Relaxation of DNA torsional tension in defined domains of bacterial chromosomes in vivo
Authors: Winston Scott , Pettijohn David E.
Published: May 2010

A procedure is described for selectively relaxing the DNA torsional tension in defined regions of the chromosome of living bacterial cells. Regions of the chromosomal DNA labelled with bromodeoxyuridine are selectively nicked by irradiation of the cells with long-wavelength ultraviolet light and then trimethylpsoralen residues are photobound to the chromosome in vivo. It is demonstrated that the rate of photobinding to the bromouridine-labelled parts of the chromosomes declines relative to the unlabelled parts of the same chromosomes as nicks are introduced into the former regions. The maximal difference in photobinding rates is that expected for the difference between relaxed and negatively supercoiled DNA. Analysis of the number of DNA breaks required for minimizing the photobinding rates permits a calculation of the number of domains of supercoiling per Bacillus subtilis chromosome.
Pleurotus ostreatus requirements for P, K, Mg, and Mn in submerged culture
Authors: Manu-Tawiah Wireko , Martin Antonio M.
Published: May 2010

The nutritional requirements of P, K, Mg, and Mn for the mycelial growth of the fungus Pleurotus ostreatus have been studied. Experiments were conducted in submerged culture using a synthetic medium and a peat-extract-based medium. Requirements for both additional phosphorus and additional potassium were detected, and supplementing the peat extract medium with potassium phosphate enhanced the mycelial growth. The addition of yeast extract and potassium phosphate, combined with the peat extract, produced the highest dry biomass concentration in this work, 6.8 g/L. Linear relationships were found between the dry biomass concentration of P. ostreatus and the concentration of KH2PO4 added to the media. No additional requirement for magnesium beyond that existing in the peat extract medium was detected. Supplementing this medium with manganese in the range of 0.1 to 0.15 g/L produced a slight increase in the growth.
Microcycle conidiation in Hirsutella thompsonii
Authors: Latgé J. P. , Cabrera R. L. Cabrera , Prévost M. C.
Published: May 2010

A fermenter method for producing conidiospores of the acarine pathogen, Hirsutella thompsonii, was developed using a strain able to produce microcycle conidiation in submerged culture. The morphological changes occurring during microcycle formation were followed under electron microscopy. Growth and sporulation patterns of the fungus were examined in batch culture. An average of 2–5 × 108 spores/mL was obtained after 3 days of growth.
Biotransformation of coal by ligninolytic Streptomyces
Authors: Gupta Rajinder K. , Spiker Jennifer K. , Crawford Don L.
Published: May 2010

The chemistry of coal liquefaction by Streptomyces viridosporus, Streptomyces setonii and Streptomyces badius was studied. These ligninolytic actinomycetes solubilized lignite and bituminous coals when coal particles were placed on the surfaces of mycelial lawns on agar culture media. On agar, liquefaction proceeded with the formation of clear to black water-soluble products. Up to 40% of some coals was solubilized in 3 weeks. Lignite coals were also solubilized in liquid shake flask cultures. Coal solubilization by S. viridosporus was oxidative, as shown by Fourier transform infrared spectroscopy and elemental analysis. Compared to the starting coals, the soluble products were enriched in oxygen, nitrogen, sulfur, and ash, but were lower in hydrogen relative to carbon. Insoluble coal residues were less altered than the liquefied products, but they were higher in ash content than the starting coals. Chemical analysis of culture filtrates showed that some low molecular weight products were released, but most of the soluble products were acid precipitable and probably polymeric. Lignite coal solubilization by the S. viridosporus did not require induction and in liquid media solubilization was always accompanied by a significant increase in medium pH. When medium pH was not allowed to become basic, extracellular coal solubilizing activity was negligible. Extracellular solubilizing activity was heat stable, and ultrafiltration experiments showed that the solubilizing agent was of less than 10 000 molecular weight. Coal solubilizing activity of S. viridosporus culture supernatants could be eliminated by lowering their pH, but the activity could be recovered by raising the pH back up to above neutral. Phosphate and Tris buffers of varying strength and pH showed that nonbiological solubilization of lignite coal occurred under basic conditions. The combined data show that biological lignite coal solubilization by these Streptomyces is mediated by alkaline products that the cells release into the growth medium. These findings confirm and expand an earlier report by others that coal solubilization by Streptomyces setonii may be nonenzymatic.
Evidence for two transporters of sulfur and selenium oxyanions in Clostridium pasteurianum
Authors: Bryant Richard D. , Laishley Edward J.
Published: May 2010

Kinetic uptake studies of the inorganic anions [Formula: see text], [Formula: see text], and [Formula: see text] into Clostridium pasteurianum showed that these dianions transport systems obeyed Michaelis–Menten kinetics. Analysis of Km and Ki values for these dianions suggest there were two ports of entry for these oxyanions into the cell, with [Formula: see text] and [Formula: see text] having a common porter and [Formula: see text] having a separate transporter. The practical importance of these experiments is related to the environment where some sediments contaminated with inorganic selenium compounds are in the concentration range which approximates the Km values for [Formula: see text](50 μM)/[Formula: see text](65 μM) in C. pasteurianum.
Gene duplication in haloaromatic degradative plasmids pJP4 and pJP2
Authors: Ghosal Debabrota , You In-Soon
Published: May 2010

pJP2 and pJP4 are 2,4-dichlorophenoxyacetic acid catabolic plasmids, and they show DNA sequence homology. Most of the pJP2 molecules (80% or more) isolated from 2,4-dichlorophenoxyacetic acid grown cells of Alcaligenes eutrophus harbor a tandem duplication of a 25-kilobase (kb) segment encoding the catabolic functions. Unlike plasmid pJP4, pJP2 in A. eutrophus gives rise to a 3-chlorobenzoate phenotype without further genetic rearrangement. pJP4 under 3-chlorobenzoate selection contains an inverted duplication of 24.5 kb. Absence of selective pressure results in the prompt loss of one copy of the duplication in pJP4, but not of the tandem duplication in pJP2. In both pJP4 and pJP2, mutation of the duplicated copy, rather than gene dosage, is likely to be the basis of phenotypic change of catabolic functions. Experiments using the cloned DNA suggest that a tandem duplication is more stable than an inverted duplication.
Human antibody response to outer membrane proteins and fimbriae of Haemophilus influenzae type b
Authors: Erwin Alice L. , Kenny George E. , Smith Arnold L. , Stull Terrence L.
Published: May 2010

We investigated the prevalence of antibodies in childrens' sera directed against outer membrane proteins (OMP) and fimbriae of Haemophilus influenzae type b. Invasive isolates of H. influenzae type b were enriched for fimbriae production; OMP and fimbriae were resolved by SDS-PAGE. After blotting to nitrocellulose, the proteins were incubated with homologous patient sera or with sera from healthy children. IgG antibodies bound to OMP were detected by immunoperoxidase staining. Immunoblotting was also performed using purified, nondenatured fimbriae as antigen. Nine of the 10 patients studied had antibodies in the acute serum directed against one or more of the OMP. Neither the acute nor the convalescent serum of the remaining patient contained antibodies against OMP. Antibodies against a greater number of OMP were present in the convalescent serum, in comparison to the acute serum, in 4 of the 10 patients. Five of 10 patients had antibodies against the purified fimbriae of an unrelated invasive isolate in either the acute or the convalescent serum. Acute sera from patients more frequently contained antibodies directed against OMP 60K (p ≤ 0.01) and OMP 51K (p ≤ 0.003) compared with the sera of healthy controls. In contrast, the sera of healthy children more frequently contained antibodies directed against OMP 40K (p ≤ 0.04). Sera from both patients and controls contained antibodies against commensal Haemophilus. We conclude that although antibodies against OMP are commonly present in healthy children, antibodies against certain OMP may be markers for susceptibility or protection.
Alteration of size of wheat root systems and nitrogen fixation by associative nitrogen-fixing bacteria measured under field conditions
Authors: Kucey R. M. N.
Published: May 2010

Spring wheat was inoculated with Azospirillum brasilense Cd or Bacillus C-11-25 under field conditions. Use of a 32P measuring technique showed that the root systems of Azospirillum-inoculated wheat occupied 54% of the soil volumes compared with uninoculated wheat plant root systems. Bacillus-inoculated wheat root systems were 82% of the size of uninoculated wheat root systems. Inoculated and control plants did not differ in dry matter production or in total N content. Inoculated plants received between 5 and 10% of the N contained in their tissues from associative N2 fixation as measured by 15N isotope dilution. Reduction of root system size in inoculated plants explains how the inoculated wheat plants in this study, and in previously reported studies, are able to absorb atmospheric N2 via associative N2 fixation without increasing total plant N uptake.
Tick-borne Kemerovo group orbiviruses in a Newfoundland seabird colony
Authors: Oprandy John J. , Schwan Tom G. , Main Andrew J.
Published: May 2010

Five new isolates of Kemerovo group viruses were recovered from Ixodes uriae collected on Great Island, Witless Bay Seabird Sanctuary, Newfoundland, Canada, during July 1985. This brings the total number of Orbivirus isolates on Great Island to 18 isolates including the 7 from 1971 and 6 from 1972. Genomic segments of several strains were compared by polyacrylamide gel electrophoresis. The degree of variation in each segment of these viruses was calculated. Great Island and Bauline viruses exhibited a great degree of variation in dsRNA migration patterns. Great Island and Bauline genomes averaged 11.60 (SD = 0.107) and 11.69 megadaltons (SD = 0.075), respectively. Variation was observed in all 10 segments of Great Island and Bauline viruses. These findings were compared with serologic and protein gel data.
Distribution of Azotobacter in Eastern Canadian soils and in association with plant rhizospheres
Authors: Kole Manoj M. , Page William J. , Altosaar Illimar
Published: May 2010

Aerobic nitrogen-fixing bacteria were readily isolated from Eastern Canadian soils. The majority (89%) of these soils were found to contain Azotobacter chroococcum and other members of this family. These bacteria ranged from 1 × 102 to 2.5 × 104 bacteria per gram soil. The soil type had relatively little effect on the population of these bacteria provided a soil moisture content of 10 to 18% and a soil pH of 6.5 to 8.0 was maintained. The presence of wheat or common lawn grasses did not promote better establishment of Azotobacteraceae. However, slightly larger populations of these bacteria were associated with corn, oat, and soybean rhizospheres.
Mise en évidence d'une activité uréasique chez Streptococcus thermophilus
Authors: Juillard V. , Desmazeaud M. J. , Spinnler H. E.
Published: May 2010

In Streptococcus thermophilus CNRZ 404, the presence of urease activity was demonstrated by means of a specific colorimetric method for ammonium ions. The main physicochemical properties of the enzyme were determined. The Km with urea as substrate was 1.19 mM and the optimal pH was approximately 7.5. Because both thermolability and enzyme activity increased as the temperature was increased to 70 °C, the optimal temperature could not be determined with precision. Urease activity was maximal at the beginning of the stationary growth phase; it was stimulated by the presence of urea and of certain amino acids such as arginine and glutamic acid in the culture medium. This activity has been detected in several other strains of Streptococcus thermophilus. [Translated by the journal]
Effect of ascorbate on oxygen uptake and growth of Escherichia coli B
Authors: Richter Holly E. , Switala Jacek , Loewen Peter C.
Published: May 2010

The addition of ascorbate to aerobically growing cultures of Escherichia coli B caused only a short pause in growth and no subsequent change in the rate or extent of growth. The effect of ascorbate on oxygen uptake varied from inhibition in minimal medium to stimulation in rich medium. Cyanide-resistant growth and oxygen uptake were stimulated by ascorbate. Both the rate and extent of anaerobic growth were stimulated in proportion to the amount of ascorbate added when fumarate was the terminal electron acceptor. Ascorbate had no effect on any aspect of anaerobic growth in the absence of a terminal electron acceptor or in the presence of nitrate.
Effect of DNA supercoiling and catabolite repression on the expression of the tetA genes in Escherichia coli
Authors: León Patricia , Alvarez Gloria , León Francisco Díaz de , Gómez-Eichelmann M. Carmen
Published: May 2010

The effect of novobiocin, a gyrase inhibitor, and of catabolite repression on the expression of different classes of tetA genes in Escherichia coli was studied. The results obtained showed that the complete induction of the tetA genes corresponding to classes A, B, and D depends on DNA supercoiling, and that the expression of the tetA genes corresponding to classes A and C is not under catabolite repression.
Production and partial characterization of elastase of Bacillus subtilis isolated from the cervices of human females
Authors: Kaur Mohinder , Tripathi K. K. , Gupta Meenakshi , Jain P. K. , Bansal M. R. , Gupta K. G.
Published: May 2010

Conditions are described for the production of extracellular elastase by Bacillus subtilis. The yield of enzyme was maximum in shake–cultures grown in Syncase medium at 37 °C and was stable in culture supernatants. The enzyme, purified by ammonium sulphate precipitation and Sephadex G-75 gel filtration, showed a molecular weight of 25 000 and activity between pH 6.0 and 9.5, with an optimum of 9.0 in Tris–maleate buffer. Elastinolytic activity was maximum in glycine–NaOH buffer and minimum in phosphate buffer. Enzyme activity was adversely affected by temperature ≥ 40 °C.
Interactions among Gaeumannomyces graminis var. tritici, Trichoderma koningii, and soil bacteria
Authors: Simon A. , Sivasithamparam K.
Published: May 2010

Interactions among Gaeumannomyces graminis var. tritici, Trichoderma koningii, and soil bacteria were studied in vitro and in soils suppressive and conducive of the saprophytic growth of G. graminis var. tritici. Fifty-four percent of bacteria isolated from the suppressive soil and 10% from the conducive soil were antagonistic to G. graminis var. tritici in vitro. The reduction in the growth of T. koningii in vitro by metabolite(s) produced in pure culture by soil bacteria was 14 and 28% for the bacteria isolated from the suppressive and conducive soil, respectively. Metabolite(s) produced by T. koningii in pure culture inhibited the growth in vitro of 8 and 65% of the bacteria isolated from the suppressive and conducive soils, respectively. All isolates of Trichoderma tested produced metabolite(s) that inhibited growth of G. graminis var. tritici in pure culture. The metabolite(s) produced by one isolate of T. koningii inhibited growth of all isolates of Trichoderma in vitro. Trichoderma koningii suppressed saprophytic growth of G. graminis var. tritici in irradiated conducive soil in the absence but not in the presence of bacteria isolated from the same soil. The results suggest that the suppressive soil may be more suppressive of the saprophytic growth of G. graminis var. tritici and less suppressive of the growth of T. koningii than the conducive soil.
Experimental evidence for enteropathogenicity in Aeromonas veronii
Authors: Stelma Jr. G. N. , Johnson C. H. , Spaulding P. L.
Published: May 2010

Eleven ornithine-positive strains of Aeromonas (9 A. veronii and 2 provisionally classified as Aeromonas species ornithine positive) were tested for ability to cause fluid accumulation in the rabbit ileal loop. All eight β-hemolytic strains caused fluid accumulation. Gel diffusion analysis revealed that the A. veronii β-hemolysin was serologically related to the A. hydrophila β-hemolysin, a known enterotoxic molecule. The biological activity of the A. veronii hemolysin was neutralized by antiserum to A. hydrophila hemolysin. One of three strains that were not β-hemolytic caused fluid accumulation but only when the ileal loops were inoculated with live cultures. These results suggest that A. veronii is a potential enteropathogen that can cause diarrhea by means of a cell-freed enterotoxin (β-hemolysin) or by a second mechanism that requires the presence of whole cells.
New marine nitrogen-fixing bacteria isolated from an eelgrass (Zostera marina) bed
Authors: Shieh Wung Yang , Simidu Usio , Maruyama Yoshiharu
Published: May 2010

Four strains of marine nitrogen-fixing bacteria were isolated from the roots of eelgrass (Zostera marina) and from sediments in an eelgrass bed in Aburatsubo Inlet, Kanagawa Prefecture, Japan. Significant levels of nitrogenase activity were detected in all four strains after a few hours of incubation under anaerobic conditions. Nitrogenase activity in all cases was Na+ dependent. These strains grew anaerobically or under conditions of low oxygen, using molecular nitrogen as the sole nitrogen source. Bacterial growth in liquid nitrogen-free medium was accompanied by a marked pH decrease during the exponential growth phase. Neither yeast extract nor vitamins were required for the nitrogen fixation activity of these strains. Taxonomically, all strains were facultatively anaerobic, Gram-negative rods. They were motile in liquid medium by means of a single polar flagellum and required NaCl for their growth. These characteristics, as well as the guanine + cytosine content of their DNA (43.5 – 44.8 mol%), placed them in the family Vibrionaceae. These strains, however, could not be identified to the genus level because they were distinct from the two halophilic genera Vibrio and Photobacterium of the family Vibrionaceae by a variety of characteristics.
Proposed virulence factors among coagulase-negative staphylococci isolated from two healthy populations
Authors: Baddour Larry M. , Smalley David L. , Hill Michelle M. , Christensen Gordon D.
Published: May 2010

Proposed virulence factors, including multiple antibiotic resistance and slime-mediated adherence, among coagulase-negative staphylococci colonizing healthy individuals from two different study populations were examined. Resistance to methicillin was more commonly seen than initially anticipated. In addition, adherence characteristics, as quantitated by a microtiter plate method, were very similar to those of strains of coagulase-negative staphylococci causing nosocomial infections.
Thymineless death in Escherichia coli mutants deficient in the RecF recombination pathway
Authors: Nakayama Koji , Shiota Susumu , Nakayama Hiroaki
Published: May 2010

Like recF and recQ mutants studied earlier, two other classes of Escherichia coli mutants defective in the RecF conjugal recombination pathway, recJ and recO, were found to be partially resistant to thymineless death. In contrast, a recN mutant, also belonging to the pathway, was indistinguishable from the wild type with respect to thymineless death.
Effect of toxins produced by various Clostridium difficile strains on cecum size reduction in gnotobiotic mice
Authors: Mahé S. , Corthier G.
Published: May 2010

Inoculation of axenic mice with Clostridium difficile strains induced a significant reduction in ceca weight (dry or wet), whereas a nontoxinogenic strain led to a partial reduction. A strain, which produces cytotoxin and no enterotoxin in vivo, caused a reduction similar to that observed with a nontoxinogenic strain. Simultaneous cytotoxin and enterotoxin production by various C. difficile strains caused the cecum size to diminish to that observed for conventional control mice.
A high molecular weight lipopolysaccharide specific bacteriophage for Klebsiella pneumoniae
Authors: Benedí Vicente J. , Ciurana Blanca , Tomás Juan M.
Published: May 2010

High-molecular weight lipopolysaccharide (O antigen enriched fraction) from Klebsiella pneumoniae was determined to be the receptor for bacteriophage FC3-1. A methodology for the identification of the lipopolysaccharide component involved in FC3-1 bacteriophage reception was used that is suitable for other phages and host bacteria.
Occurrence of enteroviruses in marine sediment along the coast of Barcelona, Spain
Authors: Bosch Albert , Lucena Francisco , Girones Rosina , Jofre Juan
Published: May 2010

A survey of the occurrence of enteroviruses in marine sediment was undertaken in an area receiving polluted effluents. Enteroviruses were detected in 21 out of 38 samples (55%). Viruses were found as far as 5 km from the shoreline and at a depth of 82 m. Multiple correlations between enteroviruses and bacteria, detected in the same samples, were computed. No correlation could be demonstrated between virus numbers and any other parameter in sediment samples collected south of Barcelona. This lack of correlation is probably due to the different decay rates shown by bacteria and viruses. In contrast, the cases where pollution resulted from a more recent deposition, as in sediment samples collected north of Barcelona, enterovirus levels were correlated with fecal streptococci levels.
Characterization of a new less acidophilic Thiobacillus isolate (Thiobacillus capsulatus)
Authors: Laishley E. J. , Rae K. , Dillman A. M. , Bryant R. D.
Published: May 2010

A motile, sulfur-oxidizing gram-negative bacterium was isolated from soil adjacent to a sulfur block pad. This isolate was found to grow only autotrophically by oxidizing S° and reduced sulfur oxyanions under aerobic conditions over a pH range of 3.0–7.0. This placed it in the less acidophilic group of Thiobacillus. The mole percent G + C of this organism was 54.5%. Ultrastructure studies showed the presence of a single polar flagellum, cytoplasmic volutin granules, and carboxysomes. An extensive glycocalyx was observed radiating outward from the outer membrane. The physiological and ultrastructure data were compared with other known thiobacilli and indicated that this isolate is a new Thiobacillus species, named T. capsulatus.
Participation des systèmes de captation des carbohydrates et de l'H+-ATPase de la membrane cytoplasmique lors de l'utilisation du glucose et du lactose par le Fusarium oxysporum var. lini
Authors: Brandão Rogelio Lopes , Nicoli Jacques Robert
Published: May 2010

Growth parameters of Fusarium oxysporum var. lini in media containing glucose or lactose as carbon source were studied in relation to biochemical phenomenons such as transport mechanisms of each carbohydrate and the cytoplasmic membrane H+-ATPase activity. The following conclusions were reached. (i) The biphasic profile of the fungal growth on the medium containing glucose could be explained by the presence of two mechanisms of glucose uptake when an inoculum with derepressed carbohydrate transport systems was used. On the other hand, the existence of only one transport system for lactose in both repressed and derepressed cells could explain the monophasic growth curve on the medium containing this disaccharide. (ii) The difference in pH profiles observed during the growth of F. oxysporum var. lini on media containing glucose or lactose as carbon source could be explained by a differential activation of the cytoplasmic membrane H+-ATPase by the two carbohydrates.