bluuebunny/crossref_metadata_2025 huggingface dataset:
Diazotrophic
Burkholderia
Species Associated with Field-Grown Maize and Sugarcane
Authors: Perin L. , Martínez-Aguilar L. , Castro-González R. , Estrada-de los Santos P. , Cabellos-Avelar T. , Guedes H. V. , Reis V. M. , Caballero-Mellado J.
Published: May 2006

Until recently, diazotrophy was known in only one of the 30 formally described species of
Burkholderia
. Novel N
2
-fixing plant-associated
Burkholderia
species such as
B. unamae
,
B. tropica
, and
B. xenovorans
have been described, but their environmental distribution is scarcely known. In the present study, the occurrence of N
2
-fixing
Burkholderia
species associated with different varieties of sugarcane and maize growing in regions of Mexico and Brazil was analyzed. Only 111 out of more than 900 isolates recovered had N
2
-fixing ability as demonstrated by the acetylene reduction assay. All 111 isolates also yielded a PCR product with primers targeting the
nifH
gene, which encodes a key enzyme in the process of nitrogen fixation. These 111 isolates were confirmed as belonging to the genus
Burkholderia
by using a new 16S rRNA-specific primer pair for diazotrophic species (except
B. vietnamiensis
) and closely related nondiazotrophic
Burkholderia
. In Mexico, many isolates of
B. unamae
(predominantly associated with sugarcane) and
B. tropica
(more often associated with maize) were recovered. However, in Brazil
B. tropica
was not identified among the isolates analyzed, and only a few
B. unamae
isolates were recovered from one sugarcane variety. Most Brazilian diazotrophic
Burkholderia
isolates (associated with both sugarcane and maize plants) belonged to a novel species, as revealed by amplified 16S rRNA gene restriction profiles, 16S rRNA gene sequencing, and protein electrophoresis. In addition, transmissibility factors such as the
cblA
and
esmR
genes, identified among clinical and environmental isolates of opportunistic pathogens of
B. cenocepacia
and other species of the
B. cepacia
complex, were not detected in any of the plant-associated diazotrophic
Burkholderia
isolates analyzed.
Comparative Genomics and Transcriptional Analysis of Prophages Identified in theGenomes of
Lactobacillus gasseri
,
Lactobacillussalivarius
, and
Lactobacillus casei
Authors: Ventura Marco , Canchaya Carlos , Bernini Valentina , Altermann Eric , Barrangou Rodolphe , McGrath Stephen , Claesson Marcus J. , Li Yin , Leahy Sinead , Walker Carey D. , Zink Ralf , Neviani Erasmo , Steele Jim , Broadbent Jeff , Klaenhammer Todd R. , Fitzgerald Gerald F. , O'Toole Paul W. , van Sinderen Douwe
Published: May 2006

Lactobacillus
gasseri
ATCC 33323,
Lactobacillus salivarius
subsp.
salivarius
UCC 118, and
Lactobacillus casei
ATCC 334
contain one (LgaI), four (Sal1, Sal2, Sal3, Sal4), and one (Lca1)
distinguishable prophage sequences, respectively. Sequence analysis
revealed that LgaI, Lca1, Sal1, and Sal2 prophages belong to the group
of Sfi11-like
pac
site and
cos
site
Siphoviridae
, respectively. Phylogenetic investigation of
these newly described prophage sequences revealed that they have not
followed an evolutionary development similar to that of their bacterial
hosts and that they show a high degree of diversity, even within a
species. The attachment sites were determined for all these prophage
elements; LgaI as well as Sal1 integrates in tRNA genes, while prophage
Sal2 integrates in a predicted arginino-succinate lyase-encoding gene.
In contrast, Lca1 and the Sal3 and Sal4 prophage remnants are
integrated in noncoding regions in the
L. casei
ATCC 334 and
L. salivarius
UCC 118 genomes. Northern analysis showed that
large parts of the prophage genomes are transcriptionally silent and
that transcription is limited to genome segments located near the
attachment site. Finally, pulsed-field gel electrophoresis followed by
Southern blot hybridization with specific prophage probes indicates
that these prophage sequences are narrowly distributed within
lactobacilli.
Genetic Diversity and Quinolone Resistance in
Campylobacter jejuni
Isolates from Poultry in Senegal
Authors: Kinana Alfred Dieudonné , Cardinale Eric , Tall Fatou , Bahsoun Ibrahim , Sire Jean-Marie , Garin Benoit , Breurec Sebastien , Boye Cheikh Saad-Bouh , Perrier-Gros-Claude Jean-David
Published: May 2006

We used the multilocus sequence typing (MLST) method to evaluate the genetic diversity of 46
Campylobacter jejuni
isolates from chickens and to determine the link between quinolone resistance and sequence type (ST). There were a total of 16 ST genotypes, and the majority of them belonged to seven clonal complexes previously identified by using isolates from human disease. The ST-353 complex was the most common complex, whereas the ST-21, ST-42, ST-52, and ST-257 complexes were less well represented. The resistance phenotype varied for each ST, and the Thr-86-Ile substitution in the GyrA protein was the predominant mechanism of resistance to quinolone. Nine of the 14 isolates having the Thr-86-Ile substitution belonged to the ST-353 complex. MLST showed that the emergence of quinolone resistance is not related to the diffusion of a unique clone and that there is no link between ST genotype and quinolone resistance. Based on silent mutations, different variants of the
gyrA
gene were shown to exist for the same ST. These data provide useful information for understanding the epidemiology of
C. jejuni
in Senegal.
Control of
Listeria
spp. by Competitive-Exclusion Bacteria in Floor Drains of a Poultry Processing Plant
Authors: Zhao Tong , Podtburg Teresa C. , Zhao Ping , Schmidt Bruce E. , Baker David A. , Cords Bruce , Doyle Michael P.
Published: May 2006

In previous studies workers determined that two lactic acid bacterium isolates,
Lactococcus lactis
subsp.
lactis
C-1-92 and
Enterococcus durans
152 (competitive-exclusion bacteria [CE]), which were originally obtained from biofilms in floor drains, are bactericidal to
Listeria monocytogenes
or inhibit the growth of
L. monocytogenes
both in vitro and in biofilms at 4 to 37°C. We evaluated the efficacy of these isolates for reducing
Listeria
spp. contamination of floor drains of a plant in which fresh poultry is processed. Baseline assays revealed that the mean numbers of
Listeria
sp. cells in floor drains sampled on six different dates (at approximately biweekly intervals) were 7.5 log
10
CFU/100 cm
2
for drain 8, 4.9 log
10
CFU/100 cm
2
for drain 3, 4.4 log
10
CFU/100 cm
2
for drain 2, 4.1 log
10
CFU/100 cm
2
for drain 4, 3.7 log
10
CFU/100 cm
2
for drain 1, and 3.6 log
10
CFU/100 cm
2
for drain 6. The drains were then treated with 10
7
CE/ml in an enzyme-foam-based cleaning agent four times in 1 week and twice a week for the following 3 weeks. In samples collected 1 week after CE treatments were applied
Listeria
sp. cells were not detectable (samples were negative as determined by selective enrichment culture) for drains 4 and 6 (reductions of 4.1 and 3.6 log
10
CFU/100 cm
2
, respectively), and the mean numbers of
Listeria
sp. cells were 3.7 log
10
CFU/100 cm
2
for drain 8 (a reduction of 3.8 log
10
CFU/100 cm
2
), <1.7 log
10
CFU/100 cm
2
for drain 1 (detectable only by selective enrichment culture; a reduction of 3.3 log
10
CFU/100 cm
2
), and 2.6 log
10
CFU/100 cm
2
for drain 3 (a reduction of 2.3 log
10
CFU/100 cm
2
). However, the aerobic plate counts for samples collected from floor drains before, during, and after CE treatment remained approximately the same. The results indicate that application of the two CE can greatly reduce the number of
Listeria
sp. cells in floor drains at 3 to 26°C in a facility in which fresh poultry is processed.
Generation of High-Affinity Chicken Single-Chain Fv Antibody Fragments for Measurement of thePseudonitzschia pungensToxin Domoic Acid
Authors: Finlay William J. J. , Shaw Iain , Reilly Joanna P. , Kane Marian
Published: May 2006

Antibody-based assay systems are now accepted by regulatory authorities for detection of the toxins produced by phytoplankton that accumulate in shellfish tissues. However, the generation of suitable antibodies for sensitive assay development remains a major challenge. We have examined the potential of using the chicken immune system to generate high-affinity, high-specificity recombinant antibody fragments against phytotoxins. Following immunization of the chicken with domoic acid-bovine serum albumin, a single-chain antibody variable region (scFv) gene library was generated from single VHand VLgenes isolated from the immune cells in the spleen and bone marrow. scFvs reacting with domoic acid were isolated by phage display and affinity matured by light chain shuffling, resulting in an approximate 10-fold increase in sensitivity. The isolated scFvs were effectively expressed inEscherichia coliand readily purified by affinity chromatography. They were then used to develop a convenient and sensitive indirect competitive enzyme-linked immunosorbent assay for domoic acid, with a 50% effective dose of 156 ng/ml, which could be used reliably with shellfish extracts. This study demonstrates that chickens provide a valuable model system for the simplified, rapid generation of high-affinity recombinant antibody fragments with specificity for small toxin molecules.
Diversity, Composition, and Geographical Distribution of Microbial Communities in California Salt Marsh Sediments
Authors: Córdova-Kreylos Ana Lucía , Cao Yiping , Green Peter G. , Hwang Hyun-Min , Kuivila Kathryn M. , LaMontagne Michael G. , Van De Werfhorst Laurie C. , Holden Patricia A. , Scow Kate M.
Published: May 2006

The Pacific Estuarine Ecosystem Indicators Research Consortium seeks to develop bioindicators of toxicant-induced stress and bioavailability for wetland biota. Within this framework, the effects of environmental and pollutant variables on microbial communities were studied at different spatial scales over a 2-year period. Six salt marshes along the California coastline were characterized using phospholipid fatty acid (PLFA) analysis and terminal restriction fragment length polymorphism (TRFLP) analysis. Additionally, 27 metals, six currently used pesticides, total polychlorinated biphenyls and polycyclic aromatic hydrocarbons, chlordanes, nonachlors, dichlorodiphenyldichloroethane, and dichlorodiphenyldichloroethylene were analyzed. Sampling was performed over large (between salt marshes), medium (stations within a marsh), and small (different channel depths) spatial scales. Regression and ordination analysis suggested that the spatial variation in microbial communities exceeded the variation attributable to pollutants. PLFA analysis and TRFLP canonical correspondence analysis (CCA) explained 74 and 43% of the variation, respectively, and both methods attributed 34% of the variation to tidal cycles, marsh, year, and latitude. After accounting for spatial variation using partial CCA, we found that metals had a greater effect on microbial community composition than organic pollutants had. Organic carbon and nitrogen contents were positively correlated with PLFA biomass, whereas total metal concentrations were positively correlated with biomass and diversity. Higher concentrations of heavy metals were negatively correlated with branched PLFAs and positively correlated with methyl- and cyclo-substituted PLFAs. The strong relationships observed between pollutant concentrations and some of the microbial indicators indicated the potential for using microbial community analyses in assessments of the ecosystem health of salt marshes.
Effects of Various Growth Conditions in a Chemostat on Expression of Virulence Factors inPorphyromonas gingivalis
Authors: Masuda Takashi , Murakami Yukitaka , Noguchi Toshihide , Yoshimura Fuminobu
Published: May 2006

Porphyromonas gingivalis, one of the gram-negative organisms associated with periodontal disease, possesses potential virulence factors, including fimbriae, proteases, and major outer membrane proteins (OMPs). In this study,P. gingivalisATCC 33277 was cultured in a chemostat under hemin excess and presumably peptide-limiting conditions to better understand the mechanisms of expression of the virulence factors upon environmental changes. At higher growth rates, the amounts of FimA and the 75-kDa protein, forming long and short fimbriae, respectively, increased significantly, whereas gingipains decreased in amount and activity. In a nutrient-limited medium, lesser amounts of the above two fimbrial proteins were observed, whereas clear differences were not found in the amounts of gingipains. In addition, two-dimensional electrophoresis revealed that proteins in cells were generally fewer in number during nutrient-limited growth. Under aeration, a considerable reduction in gingipain activity was found, whereas several proteins associated with intact cells significantly increased. However, the expression of major OMPs, such as RagA, RagB, and the OmpA-like proteins, was almost constant under all conditions tested. These results suggest thatP. gingivalismay actively control expression of several virulence factors to survive in the widely fluctuating oral environment.
Survival Strategy of
Erwinia amylovora
against Copper: Induction of the Viable-but-Nonculturable State
Authors: Ordax Mónica , Marco-Noales Ester , López María M. , Biosca Elena G.
Published: May 2006

Copper compounds, widely used to control plant-pathogenic bacteria, have traditionally been employed against fire blight, caused by
Erwinia amylovora
. However, recent studies have shown that some phytopathogenic bacteria enter into the viable-but-nonculturable (VBNC) state in the presence of copper. To determine whether copper kills
E. amylovora
or induces the VBNC state, a mineral medium without copper or supplemented with 0.005, 0.01, or 0.05 mM Cu
2+
was inoculated with 10
7
CFU/ml of this bacterium and monitored over 9 months. Total and viable cell counts were determined by epifluorescence microscopy using the LIVE/DEAD kit and by flow cytometry with 5-cyano-2,3-ditolyl tetrazolium chloride and SYTO 13. Culturable cells were counted on King's B nonselective solid medium. Changes in the bacterial morphology in the presence of copper were observed by scanning electron microscopy.
E. amylovora
entered into the VBNC state at all three copper concentrations assayed, much faster when the copper concentration increased. The addition of different agents which complex copper allowed the resuscitation (restoration of culturability) of copper-induced VBNC cells. Finally, copper-induced VBNC cells were virulent only for the first 5 days, while resuscitated cells always regained their pathogenicity on immature fruits over 9 months. These results have shown, for the first time, the induction of the VBNC state in
E. amylovora
as a survival strategy against copper.
Influence of Sporulation Medium Composition on Transcription of
ger
Operons and the Germination Response of Spores of
Bacillus cereus
ATCC 14579
Authors: Hornstra Luc M. , de Vries Ynte P. , de Vos Willem M. , Abee Tjakko
Published: May 2006

Bacillus cereus
ATCC 14579 endospores were produced in Y1 medium, a nutrient-rich, chemically defined sporulation medium, and in modified G medium, containing low amounts of nutrients. The average transcription level of the seven
ger
operons per cell was 3.5 times higher in Y1 medium, and the spores grown in this medium showed an enhanced germination response.
Novel Thermophilic Sulfate-Reducing Bacteria from a Geothermally Active Underground Mine in Japan
Authors: Kaksonen Anna H. , Plumb Jason J. , Robertson Wendy J. , Spring Stefan , Schumann Peter , Franzmann Peter D. , Puhakka Jaakko A.
Published: May 2006

Thermophilic sulfate-reducing bacteria were enriched from samples obtained from a geothermal underground mine in Japan. The enrichment cultures contained bacteria affiliated with the generaDesulfotomaculum,Thermanaeromonas,Thermincola,Thermovenabulum,Moorella, “Natronoanaerobium,” andClostridium. Two novel thermophilic sulfate-reducing strains, RL50JIII and RL80JIV, affiliated with the generaDesulfotomaculumandThermanaeromonas, respectively, were isolated.
Comparison of Cultures from Rectoanal-Junction Mucosal Swabs and Feces for Detection of
Escherichia coli
O157 in Dairy Heifers
Authors: Davis Margaret A. , Rice Daniel H. , Sheng Haiqing , Hancock Dale D. , Besser Thomas E. , Cobbold Rowland , Hovde Carolyn J.
Published: May 2006

Fecal culture for
Escherichia coli
O157:H7 was compared to rectoanal mucosal swab (RAMS) culture in dairy heifers over a 1-year period. RAMS enrichment culture was as sensitive as fecal culture using immunomagnetic separation (IMS) (
P
= 0.98, as determined by a chi-square test). RAMS culture is less costly than fecal IMS culture and can yield quantitative data.
Comparison of DNA Fingerprinting Methods for Use in Investigation of Type E Botulism Outbreaks in the Canadian Arctic
Authors: Leclair Daniel , Pagotto Franco , Farber Jeffrey M. , Cadieux Brigitte , Austin John W.
Published: May 2006

Pulsed-field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPD) analysis, and automated ribotyping were compared for epidemiological typing of
Clostridium botulinum
type E using clinical and food isolates associated with four botulism outbreaks occurring in the Canadian Arctic. All type E strains previously untypeable by PFGE, even with the use of a formaldehyde fixation step, could be typed by the addition of 50 μM thiourea to the electrophoresis running buffer. Digestion with SmaI or XhoI followed by PFGE was used to link food and clinical isolates from four different type E botulism outbreaks and differentiate them from among 39 group II strains. Strain differentiation was unsuccessful with the automated ribotyping system, producing a single characteristic EcoRI fingerprint common to all group II strains. RAPD analysis of
C. botulinum
group II strains was not consistently reproducible with primer OPJ-6 or OPJ-13, apparently discriminating between epidemiologically related strains. A modified PFGE protocol was judged to be the most useful method for typing epidemiologically related
C. botulinum
type E strains, based on its ability to type all strains reproducibly and with an adequate level of discrimination.
Rapid Differentiation between Members of the Anginosus Group and
Streptococcus dysgalactiae
subsp.
equisimilis
within Beta-Hemolytic Group C and G Streptococci by PCR
Authors: Liu Liang-Chun , Tsai Jui-Chang , Hsueh Po-Ren , Teng Lee-Jene
Published: May 2006

Based on a pair of primers developed initially for differentiating the anginosus group from other viridans streptococci, the PCR reported here can also differentiate between members of the anginosus group and
Streptococcus dysgalactiae
subsp.
equisimilis
among beta-hemolytic group C and G streptococci. The resulting 742-bp PCR product was specific for members of the anginosus group, although a smaller, nonspecific product (361 bp) was generated from
S. dysgalactiae
subsp.
equisimilis
. Restriction digestion of the amplicon with XbaI and BsmI further differentiated
Streptococcus anginosus
from
Streptococcus constellatu
s within the anginosus group.
Polymorphism of the Cell Wall-Anchoring Domain of the Autolysin-Adhesin AtlE and Its Relationship to Sequence Type, as Revealed by Multilocus Sequence Typing of Invasive and Commensal
Staphylococcus epidermidis
Strains
Authors: Sivadon V. , Rottman M. , Quincampoix J.-C. , Prunier E. , de Mazancourt P. , Bernard L. , Lortat-Jacob A. , Piriou P. , Judet T. , Gaillard J.-L.
Published: May 2006

We sequenced the adhesin-cell wall-anchoring domain of the
atlE
gene of 49 invasive and commensal
Staphylococcus epidermidis
strains. We identified 22 alleles, which could be separated into two main groups: group 1 (alleles 1 and 6 to 16, 32/49 strains) and group 2 (alleles 2 to 5 and 17 to 22, 17/49 strains). Allele 1 (the type strain sequence) was by far the most prevalent (21 of 49 strains). Multilocus sequence typing showed a clear relationship between the
atlE
allele and the sequence type (ST), with the “nosocomial” ST27 clone and closely related STs expressing group 1 alleles.
Polymorphisms in the Genes Encoding Chemokine Receptor 5, Interleukin-10, and Monocyte Chemoattractant Protein 1 Contribute to Cytomegalovirus Reactivation and Disease after Allogeneic Stem Cell Transplantation
Authors: Loeffler Juergen , Steffens Michael , Arlt Eva-Maria , Toliat Mohammad-Reza , Mezger Markus , Suk Anita , Wienker Thomas F. , Hebart Holger , Nürnberg Peter , Boeckh Michael , Ljungman Per , Trenschel Rudolf , Einsele Hermann
Published: May 2006

We analyzed 90 polymorphisms in 17 genes related to immune function for association with human cytomegalovirus (HCMV) reactivation and disease in patients after allogeneic stem cell transplantation. We found relevant markers (i) in CCR5 and IL-10 genes conferring a higher risk for the development of HCMV disease and (ii) in the MCP1 gene associated with HCMV reactivation. Testing of high-risk patients for the presence of these single-nucleotide polymorphisms might be useful for individualizing antiviral prophylaxis.
Evaluation of the Q Score and Q234 Systems for Cost-Effective and Clinically Relevant Interpretation of Wound Cultures
Authors: Matkoski Carol , Sharp Susan E. , Kiska Deanna L.
Published: May 2006

The Q score and Q234 systems were compared to our current protocol for interpreting wound cultures. The Q score and Q234 systems were more cost effective than our current method, with the Q234 system being considered the most useful protocol for implementation by both the laboratory and our clinicians.
Pyranoquinolines. Part I. Syntheses and ultraviolet absorption characteristics of 6-chloro-4H-pyrano[3,2-h]quinoline-4-ones
Authors: Patel D. R. , Choxi C. S. , Patel S. R.
Published: May 2006

6-Chloro-2-phenyl and 2-p-anisyl-4H-pyrano[3,2-h]quinoline-4-ones, their 2,3-dihydro and 3-hydroxy derivatives, and 6-chloro-3-benzoyl-2-phenyl-4H-pyrano[3,2-h]quinoline-4-one are synthesized by the application of appropriate flavonoid syntheses to 5-chloro-7-acetyl-8-hydroxyquinoline (5). 5 was formed on Friedel–Crafts acetylation of 5-chloro-8-methoxy and -8-hydroxyquinolines. Ultraviolet spectra of 5 are studied at three different pH's in aqueous ethanol and those of the pyranoquinolines are studied in ethanolic solutions and compared with those of their corresponding simple flavonoids.
Electron spin resonance study of tert-butyl halides and carbon tetrachloride, neopentane and carbon tetrachloride binary mixtures irradiated at 77 °K
Authors: Thyrion F. C.
Published: May 2006

Tert-butyl halides and carbon tetrachloride, neopentane and carbon tetrachloride binary mixtures were irradiated at 77 °K and electron spin resonance spectra were recorded at increasing temperatures until the radicals disappeared.Even at high concentrations of tert-butyl halides, the radicals obtained from CCl4 predominate, indicating that CCl4 has a high efficiency for electron capture. Maximum radical yields and the appearance of a narrow line spectrum with rising temperature were observed in (CH3)3C—X – CCl4 mixtures (X = Cl, Br, I) in concentration ranges where only a single phase exists. This spectrum consists of 17 lines which appear to belong to one odd-numbered spectrum (7 lines due to (CH3)2Ċ—X radical) and two even-numbered spectra (4 and 10 lines, the last being due to (CH3)3Ċ radical). The disappearance of the CCl4 broad band and the appearance of these radicals with increasing temperature can be interpreted as due to charge transfer from carbon tetrachloride cation to tert-butyl halide, facilitated by greater freedom of movement in the solid solutions. In contrast, neopentane and carbon tetrachloride mixtures do not display these features.
Some enzymic syntheses of 15N-L-aspartic acid and 15N-L-glutamic acid
Authors: Zintel J. A. , Williams A. J. , Stuart R. S.
Published: May 2006

Some methods for the preparation of 15N-L-aspartic acid and 15N-L-glutamic acid using enzyme catalyzed reactions are described. 15N-L-Aspartic acid is prepared by the addition of ammonia to fumaric acid, catalyzing the reaction with aspartase which was partially purified from E. coli. 15N-L-Glutamic acid with a high 15N/14N ratio is prepared by transamination with 15N-L-aspartic acid catalyzed by aspartate aminotransferase. 15N-L-Glutamic acid with a low 15N/14N ratio is prepared by a glutamic acid dehydrogenase catalyzed exchange of L-glutamic acid with 15N-ammonia. These enzymes are commercially available. Since efficient utilization of 15N is obtained, aspartic acid or glutamic acid may be prepared with any desired 15N/14N ratio.
Inefficiency and reversibility in the photodimerization of 2-cyclopentenone
Authors: Wagner Peter J. , Bucheck David J.
Published: May 2006

The maximum efficiency for photodimerization of cyclopentenone in acetonitrile is 36%. The intermediacy of metastable dimeric species, 64% of which revert to two ground state molecules, is indicated.
Relative stereochemistry of altersolanol A
Authors: Stoessl A.
Published: May 2006

Altersolanol A (1) forms a monoisopropylidene derivative which in turn yields a triacetate and a dimethylether monoacetate. Both of the latter compounds can be aromatized but the products indicate that either an acyl or a methyl migration has taken place. The former possibility is considered to be much more likely. This and other considerations lead to structure 2 for altersolanol A acetonide. Analysis of the nuclear magnetic resonance spectra of 1 and 2 and their derivatives allows assignments of their relative configurations and conformations as 7 and 8 respectively.
Nuclear magnetic resonance study of intramolecular electronic effects in diphenyl sulfides, sulfoxides, and sulfones
Authors: Hyne J. B. , Greidanus J. W.
Published: May 2006

A nuclear magnetic resonance (n.m.r.) method has been applied to the study of variations in electron density in the aromatic rings of para-disubstituted diphenyl sulfides, sulfoxides and sulfones. The n.m.r. response of the aromatic ring protons has been determined as a function of the nature of the para substituents and particularly as a function of the nature of the bridging group between the rings. Certain diphenyl ethers and diphenyl methanes have been investigated for comparison purposes. The results establish that a transmission mechanism is operative through sulfur in diphenyl sulfides that is not effective when the bridging function is sulfoxide or sulfone. The extent to which transmission is operative even in the sulfides is dependent on the precise nature of the para substituents, in particular whether they are donors or acceptors and the manner in which they interact with the remainder of the molecule.
Enzymic deacylation of esterified mono- and disaccharides. 2. The chemical synthesis of 2,3-di-O-acetyl-D-glucopyranose
Authors: Fink A. L. , Hay G. W.
Published: May 2006

2,3-Di-O-acetyl-D-glucopyranose was synthesized by catalytic (paladium on carbon) hydrogenation of benzyl 2,3-di-O-acetyl-4,6-O-benzylidene-β-D-glucoside.
Facile preparation of thioacetals in neutral medium starting from sodium borohydride
Authors: Lalancette J. M. , Lachance A.
Published: May 2006

Sodium borohydride can be sulfurated to give NaBH2S3. The sulfurated hydride, when treated with a mercaptan, gives an orthothioborate: (RS)3B. The orthoborates react with aldehydes and ketones to give the corresponding thioacetals with quantitative yields, in neutral medium.
Synthesis of 9-β-D-arabinofuranosyl-9H-purine-6(1H)-thione-5′-phosphate
Authors: Bell John Perkins
Published: May 2006

The 5′-phosphate of 9-β-D-arabinofuranosyl-9H-purine-6(1H)-thione was obtained by selective protection of the 2′- and 3′-positions followed by phosphorylation with β-cyanoethyl phosphate.
Some derivatives of 1-benzazepine
Authors: Rees A. H. , Simon K.
Published: May 2006

A new rearrangement of a substituted 5H-1-benzazepine-5-one is described. A new route to certain dimethyl-1-benzazepines has been developed and linked up with a known synthesis. Several new derivatives of 1-benzazepine are reported.
Nucleophilic substitution at silicon: the reaction of triphenylsilyl chloride with 2-propanol in CCl4
Authors: Allen A. D. , Lavery S. J.
Published: May 2006

The reaction of triphenylsilyl chloride with 2-propanol in CCl4 has been reinvestigated and a mechanism proposed. The HCl produced in the reaction is catalytic. The rate of the uncatalyzed reaction, as determined by extrapolations to zero time, increases more rapidly with 2-propanol concentration than would be required for an order of one in the alcohol. The rate of the HCl-catalyzed path is independent of the 2-propanol concentration in the range studied (5 to 15 volume %) but first order in the HCl concentration, suggesting that the reactive alcohol species in this case is of the form ROH … ClH.
Alcaloïdes stéroïdiques. LXXXIX. Transposition d'une N-chloroazétidine. Synthèse partielle du cyclo-18(N) méthoxy-17ξ aza-17aD-homo androstane-5α
Authors: Benezra Claude , Lusinchi Xavier
Published: May 2006

Treatment of 18(N)-cyclo-17β-amino-5α-androstane, 5 under Ruschig conditions [(1) sodium hypochlorite; (2) sodium methoxide in methanol] gave the rearranged 18(N)-cyclo-17ξ-methoxy-17a-aza-D-homo-5α-androstane, 7. The structure of this compound has been proved chemically: hydrogenolysis of 7, followed by formylation, gave N-formyl-17a-aza-D-homo-5α-androstane, 9 prepared independently from 5α-androstan-17β-ol. Infrared, nuclear magnetic resonance, and mass spectra are discussed and related rearrangements are briefly reviewed.
Distribution of substituent groups in O-(2-aminoethyl)cellulose
Authors: Roberts E. J. , Rowland S. P.
Published: May 2006

O-(2-Aminoethyl)cellulose (degree of substitution 0.14), prepared by reaction of sodium 2-aminoethyl sulfate with cotton fabric, was hydrolyzed to glucose and mono-O-(2-aminoethyl)-D-glucopyranoses which were identified by gas–liquid chromatography (g.l.c.). Complications arise from reactions between the functional group at C-1 of the glucose unit and the amine function of a substituent. The distribution of 2-aminoethyl substituents in the 3-O- and 6-O-positions of the D-glucopyranosyl units of cotton cellulose was estimated to be 0.20:1.00 from direct analysis of the hydrolyzate of O-(2-aminoethyl)cellulose, but the total substitution in the 2-O-position could not be estimated in this manner. The ratio of substituents in the 2-O-, 3-O-, and 6-O-positions was found to be 0.64:0.14:1.00 when the amino groups were converted to hydroxyl groups by diazotization, and the distribution was estimated in terms of the 2-hydroxyethyl substituents. It has been observed that a substantial fraction (57.5%) of the 2-O-(2-hydroxyethyl)-D-glucose from the chemically modified cellulose exists in the form of the inner glucosides. Several new monosubstituted glucoses have been prepared and characterized by g.l.c. for this purpose.
Inner glucosides of the anomeric 2-O-(2-hydroxyethyl)-D-glucoses
Authors: Roberts E. J. , Rowland S. P.
Published: May 2006

It has been found that 2-O-(2-hydroxyethyl)-D-glucopyranose is partially converted to 1,2-O-ethylene-α-D-glucofuranose, 1,2-O-ethylene-α-D-glucopyranose, and 1,2-O-ethylene-β-D-glucopyranose when heated in dilute acid solution. The ratio of the furanose derivative to the pyranose derivatives is dependent upon the concentration of the acid (3, 5). The three inner glucosides of 2-O-(2-hydroxyethyl)-D-glucose have been characterized by gas-liquid chromatography. The interrelationship of 2-O-(2-hydroxyethyl)-D-glucose and its inner glucosides is also reported.
Fluoranthene studies. IV. Nitration of 2-nitro-, 3-nitro-, and 2-acetamido-fluoranthene
Authors: Charlesworth E. H. , Lithown Caroline U.
Published: May 2006

Nitration of 3-nitrofluoranthene yields 3,9-dinitrofluoranthene, and nitration of 2-acetamidofluoranthene yields 2-acetamido-3-nitrofluoranthene. The orientation of both these compounds has been proved. Nitration of 2-nitrofluoranthene has given a dinitro product, but its orientation has not been established. A number of other new fluoranthene derivatives are described.
Negative ion – molecule reactions
Authors: Ferguson E. E.
Published: May 2006

Laboratory reaction rate constant measurements for negative ion – atom interchange reactions, negative ion charge transfer reactions, and negative ion three-body association reactions of aeronomic interest are reviewed and the available data tabulated. The present experimental techniques in use are briefly summarized. Most of the rate constants have been measured only at 300 °K; in a few cases data is available at energies [Formula: see text] as well as at 300 °K, so that an indication of the energy dependence of the rate constants is available.
Absorption cross-sections of atmospheric gases for use in aeronomy
Authors: Huffman Robert E.
Published: May 2006

The current status of absorption cross-section measurements for aeronomic use is reviewed. Recommended values for the gases O2, N2, O, and O3 are given at wavelengths where there is strong atmospheric absorption in the 3500–10 Å region. A table of absorption and ionization cross-sections at important solar emission lines is given. The problem of insufficient resolution at some wavelengths is discussed, and information on photolysis products is given where available.
The collisional deactivation of metastable atoms and molecules in the upper atmosphere
Authors: Zipf E. C.
Published: May 2006

It is now possible to produce comparatively large concentrations of highly reactive metastable species in laboratory sources and to study metastable atoms and molecules with very long radiative lifetimes by photoionization mass spectroscopy, by vacuum ultraviolet absorption techniques, or by direct observation of the feeble radiation emitted by these excited species. These methods are being used widely to study the collisional deactivation of aeronomically important metastable species by quenching or by reaction. New information on radiative lifetimes, diffusion coefficients, and reaction rate coefficients is now available. These results are tabulated and reviewed in the light of atmospheric measurements and current theories of the terrestrial airglow and aurora.
Translational freezing in free jet expansions, with special reference to molecular beam formation
Authors: LeRoy Rodney L. , Deckers Jacques M.
Published: May 2006

A theoretical model is described which can be used to calculate the velocity distribution function in the transition region of a free jet expansion. It makes use of a simple mechanism to account for the way in which collisions "perturb" the distribution function which would apply in the absence of collisions. The results are compared with experimental studies of argon beams isolated from free jet sources. If the collision frequency is calculated using a hard sphere collision cross section of (25 ± 5) Å2, good agreement with experimental beam intensity profiles is obtained. In the transition region computed values of the bulk mass velocity, and of the parallel and perpendicular temperatures, are intermediate between the values which would be found if the flow were collision-dominated or free molecular. In particular the perpendicular temperature varies slowly from a dependence on the −4/3 power of the distance from the source, approaching monotonically a −2 power dependence at large distances.
Sur les tert-butyl-4 triméthyl-1,2,2 cyclohexanols epimères
Authors: Richer Jean-Claude , Lamarre Claude
Published: May 2006

not available
Contribution à l'étude du mécanisme d'oxydation chromique de cycloalcanols secondaires
Authors: Richer Jean-Claude , Thanh Hoa Nguyen Thi
Published: May 2006

not available
Thermal decomposition of alkyl N-(o-nitrophenyl)carbamates: A novel synthesis of benzofurazan
Authors: Prokipcak J. M. , Forte P. A. , Lennox D. D.
Published: May 2006

Several alkyl N-(o-nitrophenyl)carbamates have been shown to undergo thermal breakdown to give benzofurazan with the methyl derivative giving the optimum results.
Carbon-13 kinetic isotope effects. V. Substituent effects on k12/k13 for alcoholysis of 1-phenyl-1-bromoethane
Authors: Bron Jan , Stothers J. B.
Published: May 2006

As a test of our earlier interpretations of the 13C kinetic isotope effects found for alcoholysis of 1-phenyl-1-bromoethane, we have examined the effect of the p-methyl and p-bromo substituents on the 13C fractionations in ethanol and methanol. Isotopic fractionation at the α-carbon is found to be substituent dependent, and the observed trend is consistent with the proposal that stabilization of the cationic center by the phenyl ring is a major factor governing the isotope effect in these systems. The first example of an inverse primary kinetic isotope effect for carbon (k12/k13 < 1) is described.
Photo-initiated reactions of thiols and olefins. III. Addition of methanethiol to acetylene and butadiene-1,3
Authors: Graham D. M. , Soltys J. F.
Published: May 2006

The kinetics of addition of methanethiol to acetylene and butadiene-1,3 have been investigated. The butadiene reaction exhibits no chain character due to the low reactivity of the adduct radical formed, and no rate constants could be determined. Thiyl radical addition to acetylene was found to be reversible at 25 °C, and the results obtained are consistent with the mechanism previously postulated for olefins, except that in this case, the rate of dehydrogenation of thiol by the adduct radical is comparable to the rate of radical decomposition. This competition permitted determination of the ratio of rate constants for these two reactions, and the rate constant for thiyl radical attack on acetylene.
Infrared study of the interactions of acetone and siliceous surfaces
Authors: McManus J. C. , Harano Yoshio , Low M. J. D.
Published: May 2006

Adsorbed acetone is held to silica surfaces by hydrogen bonds between surface silanols and the acetone carbonyl groups. Acetone is adsorbed by this mechanism on porous glass surfaces but there is also some decomposition, as shown by the increase in surface B—OH groups and by formation of new C—H absorptions at 2984 and 2940 cm−1. Experiments with boron-impregnated silica indicated that the presence of boron in the porous glass can account for this decomposition process. Bands at 1660–1670 and 1650 cm−1, observed when acetone and acetone-d6, respectively, were adsorbed on either porous glass or boron-impregnated silica, are attributed to ν(C=O) of the carbonyl group coordinated with a surface boron atom. The surface hydroxyls of both silica and porous glass could exchange with the deuterium of acetone-d6 via a mechanism involving an enol intermediate.
The germanium–selenium phase diagram
Authors: Ross L. , Bourgon M.
Published: May 2006

The Ge–Se phase diagram was determined in the composition range 0–66.67 at. % Se by the method of differential thermal analysis. The diagram differs totally from the one reported by Liu etal. (1) but is in good agreement with the diagram recently reported by Karbanov etal. (13). In its broad features the Ge–Se phase diagram is quite similar to the diagrams of the Ge–S, Sn–S, and Sn–Se systems.
N-Chlorination of secondary amides. I. Kinetics of N-chlorination of N-methyl acetamide
Authors: Wayman M. , Thomm E. W. C. W.
Published: May 2006

The rate of N-chlorination of N-methyl acetamide has been studied in acetate buffered hypochlorous acid solutions. The reaction rate is dependent upon pH, chloride ion concentration, and acetic acid concentration. The results fit the following rate expression[Formula: see text]The observed rate constant, kobs, has three components[Formula: see text]The results suggest that the active chlorinating species in the pH range 3.0–6.0 are HOCl, Cl2, and CH3COOCl, in order of increasing reactivity. The values of the corresponding rate constants at 25 °C are [Formula: see text], and [Formula: see text] l mole−1 min−1, the last two rate constants being related to k2 and k3 through the respective equilibrium constants.At temperatures near room temperature, the N-chlorination reaction has an apparent activation energy of 14 kcal/mole when Cl2 is the active species, and 5 kcal/mole when CH3COOCl is the chlorinating agent.
Circular dichroism of copper(II) carboxylates
Authors: Smith Anthony A. , Haines Roland A.
Published: May 2006

The circular dichroism (c.d.) spectra of anhydrous copper(II) acetate, copper(II) isobutyrate, and copper(II) allylacetate in d-1,2-propanediol are interpreted as showing that all the d → d transitions are contained in a single band envelope with relative energies of the d orbitals being [Formula: see text] A possibility for the origin of a c.d. band at ∼300 mμ is suggested.
Two linear correlations of pKavs. solvent composition
Authors: Gowland Joan A. , Schmid George H.
Published: May 2006

The dissociation constants, pKa, of pyridine, n-pentylamine, triethanolamine, and benzylamine were studied in a series of ethanol–water and dimethyl sulfoxide – water solvent systems. Linear correlations were found between the pKa of these amines and Kosower's Z values and weight % water content of the solvent.
Fragmentation reactions promoted by cyanogen bromide
Authors: Casy A. F. , Hassan M. M. A. , Parulkar A. P.
Published: May 2006

The fragmentation of α-4-dimethylamino-3-methyl-1,2-diphenylbutan-2-ol to cis H/Ph 3-methyl-1,2-diphenylprop-2-ene, normally induced by treating the corresponding 2-chloro derivative with a base, also results when the alcohol itself is treated with cyanogen bromide; related γ-hydroxy acyclic tertiary amines similarly undergo fragmentation in this reaction. In contrast, cyclic analogues such as β-1,3-dimethyl-4-phenyl-4-piperidinol are not cleaved by cyanogen bromide (corresponding N-cyano derivatives are formed in low yield) even though β-4-chloro-1,3-dimethyl-4-phenylpiperidine is fragmented by potassium cyanide to trans H/Ph 5(N-cyanomethyl-N-methylamino)-3-phenylpent-2-ene.
Réactions des acides aminés avec l'épithiocyclohexane
Authors: Jankowski Krzysztof , Gauthier Roger , Berse Casimir
Published: May 2006

not available
Photolysis and mass spectra of trans-cinnamimide
Authors: Lalonde Robert T. , Davis Curry B.
Published: May 2006

Using Pyrex filtered light, irradiation of trans-cinnamimide in 1,2-dimethoxyethane solution gave β-truxinimide (48% yield), cis-cinnamamide and trans-cinnamamide. Both trans-cinnamimide and β-truxinimide undergo fragmentation in the mass spectrometer to give C16H14 +, C16H13 +, C16H12 +, and C14H12 +.
On the use of a polyelectrolyte in a thermocell
Authors: Breck W. G. , King E.
Published: May 2006

not available
13C Nuclear magnetic resonance studies. XIV. Conformational effects on carbinyl carbon shieldings in cyclohexanols and derivatives
Authors: Buchanan G. W. , Stothers J. B.
Published: May 2006

The 13C shieldings of the alicyclic carbons bearing oxygen in several cyclohexanols, their acetates and methyl ethers depend on the orientation of the oxygen functions. The compounds examined include the cis- and trans-4-alkyl derivatives in which the alkyl groups are t-butyl,i-propyl, ethyl and methyl, as well as the 3-t-butyl isomers. The results for the parent compounds are employed for the estimation of the conformational free energies of the hydroxyl, acetoxyl, and methoxyl groups, and serve to establish that 13C magnetic resonance (c.m.r.) spectroscopy offers a new approach to conformational analysis. The data were obtained using the decoupling technique and materials containing 13C in natural abundance.
A steroidal 14β-hydroperoxide
Authors: Afonso Adriano
Published: May 2006

Air oxidation of Δ14-androsten-3β-ol-17-one acetate (1) was found to afford stereospecifically 14β-hydroperoxy-Δ15-androsten-3β-ol-17-one 3-acetate (2a).
Electrolysis in liquid ammonia solution in peptide chemistry
Authors: Ives D. A. J.
Published: May 2006

An adaptation of an electrolytic method is suggested for the removal of protecting groups in peptide chemistry. Some initial experiments are reported indicating the scope and possible limitations of the method.
Chromatographic analysis of methyl ethers of 2-amino-2-deoxy-D-glucopyranose
Authors: Perry M. B. , Webb Ann C.
Published: May 2006

The mono-, di-, and tri-O-methyl ether derivatives of 2-amino-2-deoxy-D-glucopyranose have been analyzed by gas–liquid chromatography of their fully acetylated 2-acetamido-2-deoxy-D-glucitol derivatives which were prepared from the glycoses by reduction with sodium borohydride followed by acetylation with acetic anhydride. The methyl ethers of 2-amino-2-deoxy-D-glucopyranose were also characterized by degradation with ninhydrin to the corresponding methyl ether derivatives of D-arabinose which were identified by paper chromatography.
Electrical conductivity studies of fluorosulfuric acid and tetramethylammonium fluorosulfate in nitrobenzene
Authors: Reed W. , Secret D. W. , Thompson R. C. , Yeats P. A.
Published: May 2006

Electrical conductivity data for solutions of tetramethylammonium fluorosulfate and fluorosulfuric acid in nitrobenzene are reported. The dissociation constant of the tetramethylammonium salt is 2.0 × 10−2 and the mobility of the fluorosulfate ion is 21.4. Although the conductivity data for solutions of fluorosulfuric acid could not be treated rigorously, it is shown that in dilute solutions, fluorosulfuric acid undergoes rather weak dissociation with a dissociation constant estimated to be less than 6 × 10−6. This result is contrasted with earlier work which showed that nitrobenzene is fully protonated and dissociation into ions is complete when fluorosulfuric acid forms the bulk solvent.
Addition of pseudohalogens to unsaturated carbohydrates. III. Synthesis of 3-deoxy-3-C-nitromethyl-D-allose, a branched-chain nitro sugar
Authors: Szarek W. A. , Jewell J. S. , Szczerek I. , Jones J. K. N.
Published: May 2006

Addition of nitryl iodide to 3-deoxy-1,2:5,6-di-O-isopropylidene-3-methylene-α-D-ribo-hexofuranose (2), followed by treatment of the product with sodium borohydride, gave crystalline 3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-nitromethyl-α-D-allofuranose (3); the branched-chain unsaturated sugar (2) was prepared by way of a Wittig reaction with 1,2:5,6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose (1). Acid-catalyzed hydrolysis of 3 afforded 3-deoxy-3-C-nitromethyl-D-allose, which exists predominantly in the β-D-furanose form (4).
Sulfene
Authors: King J. F. , Mayo P. De , Verdun D. L.
Published: May 2006

Evidence indicating the existence of sulfene (CH2=SO2) as a discrete species in the gas phase is presented.
Catalytic reduction of dimethylsulfoxide by molecular hydrogen using rhodium(III) complexes
Authors: James B. R. , (Miss) F. T. T. Ng , Rempel G. L.
Published: May 2006

Dimethylsulfoxide is reduced by molecular hydrogen under mild conditions to dimethylsulfide and water in the presence of rhodium(III) complexes as catalysts. The kinetics of the systems using RhCl3.3H2O and cis-RhCl3(Et2S)3 have been investigated, and a mechanism involving reduction of coordinated dimethylsulfoxide in a rhodium(III) hydride complex is postulated. The catalytic efficiency of the systems decreases slowly due to the production of inactive rhodium(I) species.
Kinetics of the reaction of methyl iodide with sulfite and thiosulfate ions in aqueous solution
Authors: Hasty R. A. , Sutter S. L.
Published: May 2006

The rate of reaction of methyl iodide with sulfite ion is determined. In addition, the rate of reaction of methyl iodide with thiosulfate ion is reexamined and the rate of reaction of methyl iodide with bisulfite ion is estimated. A pronounced effect of ionic strength on the reaction rate in the methyl iodide – sulfite ion system is observed, this effect does not occur in the methyl iodide – thiosulfate ion system. The second order reaction rate constant and activation energy for the reaction of methyl iodide with the respective nucleophiles are: SO32−, 4.4 × 10−2M−1 s−1, 18.6 kcal mole−1; HSO3−, 1 × 10−3M−1 s−1, 18.4 kcal mole−1; and S2O32− 3.1 × 10−2M−1 s−1, 19.4 kcal mole−1.
Thermal expansion and structure in water and aqueous solutions
Authors: Hepler Loren G.
Published: May 2006

The thermodynamic equation (∂CP/∂P)T = −T(∂2V/∂T2)P is used as a basis for relating thermal expansion to structure (at several temperatures and pressures) of water and "normal" liquids. Similar considerations lead to a relation between the sign of [Formula: see text] for solutions and classification of solutes as structure-making or structure-breaking.