bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Cytomegalovirus IE72 Protein Interacts with the Transcriptional Repressor hDaxx To Regulate LUNA Gene Expression during Lytic Infection
Authors: Reeves Matthew , Woodhall David , Compton Teresa , Sinclair John
Published: May 2010

A putative latency-associated transcript (LUNA) complementary to the human cytomegalovirus (HCMV) UL81-82 region previously identified in seropositive donors' monocytes is also expressed during lytic infection. Thus, the LUNA promoter is active during both lytic and latent infection. Consequently, the mechanisms regulating this promoter may provide further insight into factors that determine whether the outcome of HCMV infection is latent or lytic. By transfection, the LUNA promoter exhibited low but reproducible activity. Substantial activation by virus infection suggested that a viral factor was important for LUNA expression during lytic infection. IE72, a known transactivator of viral promoters, activated the LUNA promoter in cotransfection assays. Furthermore, coinfection with wild-type HCMV but not an IE72 deletion virus (CR208) also activated the LUNA promoter. Finally, diminished LUNA gene expression in CR208 virus-infected cells supported a role for IE72 in LUNA gene expression. The initial regulation of herpesvirus immediate-early gene expression is associated with proteins found at cellular nuclear domain 10 (ND10) bodies, such as PML, hDaxx, and ATRX. hDaxx transfection repressed LUNA promoter activity. Furthermore, we observed binding of hDaxx to the LUNA promoter, which was abrogated by IE72 gene expression via direct interaction. Finally, we show that small interfering RNA (siRNA) knockdown of the hDaxx interaction partner ATRX rescued LUNA gene expression in CR208-infected cells. Overall, these data show that hDaxx/ATRX-mediated repression of LUNA during lytic infection absolutely requires IE72 gene expression. It also suggests that the targeting of cellular factors by IE72 is important throughout the different phases of HCMV gene expression during productive infection.
Attenuated
Bordetella pertussis
Protects against Highly Pathogenic Influenza A Viruses by Dampening the Cytokine Storm
Authors: Li Rui , Lim Annabelle , Phoon Meng Chee , Narasaraju Teluguakula , Ng Jowin K. W. , Poh Wee Peng , Sim Meng Kwoon , Chow Vincent T. , Locht Camille , Alonso Sylvie
Published: May 2010

The threat of a pandemic spread of highly virulent influenza A viruses currently represents a top global public health problem. Mass vaccination remains the most effective way to combat influenza virus. However, current vaccination strategies face the challenge to meet the demands in a pandemic situation. In a mouse model of severe influenza virus-induced pneumonitis, we observed that prior nasal administration of an attenuated strain of
Bordetella pertussis
(BPZE1) provided effective and sustained protection against lethal challenge with two different influenza A virus subtypes. In contrast to most cross-protective effects reported so far, the protective window offered upon nasal treatment with BPZE1 lasted up to at least 12 weeks, suggesting a unique mechanism(s) involved in the protection. No significant differences in viral loads were observed between BPZE1-treated and control mice, indicating that the cross-protective mechanism(s) does not directly target the viral particles and/or infected cells. This was further confirmed by the absence of cross-reactive antibodies and T cells in serum transfer and
in vitro
restimulation experiments, respectively. Instead, compared to infected control mice, BPZE1-treated animals displayed markedly reduced lung inflammation and tissue damage, decreased neutrophil infiltration, and strong suppression of the production of major proinflammatory mediators in their bronchoalveolar fluids (BALFs). Our findings thus indicate that protection against influenza virus-induced severe pneumonitis can be achieved through attenuation of exaggerated cytokine-mediated inflammation. Furthermore, nasal treatment with live attenuated
B. pertussis
offers a potential alternative to conventional approaches in the fight against one of the most frightening current global public health threats.
Assisted suicide and the killing of people? Maybe. Physician-assisted suicide and the killing of patients? No: the rejection of Shaw's new perspective on euthanasia
Authors: McLachlan Hugh V
Published: May 2010

David Shaw presents a new argument to support the old claim that there is not a significant moral difference between killing and letting die and, by implication, between active and passive euthanasia. He concludes that doctors should not make a distinction between them. However, whether or not killing and letting die are morally equivalent is not as important a question as he suggests. One can justify legal distinctions on non-moral grounds. One might oppose physician-assisted suicide and active euthanasia when performed by doctors on patients whether or not one is in favour of the legalisation of assisted suicide and active euthanasia. Furthermore, one can consider particular actions to be contrary to appropriate professional conduct even in the absence of legal and ethical objections to them. Someone who wants to die might want only a doctor to kill him or to help him to kill himself. However, we are not entitled to everything that we want in life or death. A doctor cannot always fittingly provide all that a patient wants or needs. It is appropriate that doctors provide their expert advice with regard to the performance of active euthanasia but they can and should do so while, qua doctors, they remain hors de combat.
Is supervised community treatment ethically justifiable?
Authors: Dale Eric
Published: May 2010

Ethical viewpoints for and against the use of supervised community treatment (SCT), also known as outpatient commitment and community treatment orders, are examined. The perspectives of writers on civil liberties are considered. This paper argues that while civil liberties are an important concern SCT is ethically justifiable in the circumscribed population of ‘revolving door’ patients it applies to. This is on the grounds that it enables individuals to actualise their positive liberty. The issue of insight into mental illness is also considered and it is concluded that a further argument in favour of SCT comes from evidence that insight relates to neurobiological deficits. Limits to the ethical justifiability of SCT are considered with reference to individuals with substance dependency. The paper concludes that SCT is ethically permissible only in those with severe mental illness who have a history of losing capacity to consent to treatment and/or admission.
Psychosocial work environment and risk of ischaemic heart disease in women: the Danish Nurse Cohort Study
Authors: Allesøe Karen , Hundrup Yrsa Andersen , Thomsen Jane Frølund , Osler Merete
Published: May 2010

Objectives

To investigate the effect of work pressure and job influence on the development of ischaemic heart disease (IHD) in women.

Methods

The effect of work pressure and job influence on the 15-year incidence of IHD in women participating in the Danish Nurse Cohort Study was prospectively studied. A total of 12 116 participants, aged 45–64 years, were examined in 1993 using a questionnaire and were followed by individual linkage in the National Register of Hospital Discharges to the beginning of 2008. Work pressure, job influence, occupational characteristics, demographic factors and known biological and behavioural risk factors for IHD were collected at baseline.

Results

During follow-up, 580 participants were hospitalised with IHD. In the fully adjusted model, nurses who reported work pressure to be much too high had a 1.4-fold increased risk of incident IHD (95% CI 1.04 to 1.81) compared with nurses who reported work pressure to be suitable. A tendency towards a dose–response effect was found. Age-stratified analysis showed that this effect was significant only among the younger nurses (<51 years old at baseline). No association was found between job influence and IHD.

Conclusions

In this study we find that work pressure that is too high is a significant risk factor for IHD in younger female employees (<51 years of age). The results should be taken into account in the planning of primary prevention.
Using transactional analysis to improve clinical and educational supervision: the Drama and Winner’s triangles
Authors: McKimm Judy , Forrest Kirsty
Published: May 2010

The supervisor–trainee relationship is fundamental in ensuring the best continuing education for all trainees. One of the key skills of supervision is being able to communicate effectively; however, this is sometimes difficult. In this article we explore how two transactional analysis models, the Drama and Winner’s triangles, can help supervisors work and communicate more effectively with trainees.

All supervisors will have had a ‘heartsink moment’ before meeting a known trainee. The models can be used to explain these situations and what exactly is happening to the communication. The models provide methods of breaking free from these frustrating encounters and moving on with the relationship with your trainee.

The models also help us understand the ways in which we can easily be pulled into games and offer insight into our own behaviours and relationships, not only with trainees, but also with patients, carers and colleagues. Real life scenarios are used throughout to explain the models.
Absence of competition between salmonella phage P22 and coliphage P1 for adsorption sites on a Salmonella typhosa – Escherichia coli hybrid strain
Authors: Karunakaran V. , Mojica-a T. , Middleton R. B.
Published: May 2010

Salmonella typhimurium mutants sensitive to coliphage P1 are resistant to salmonella phage P22 and lose their P1-sensitivity upon reversion to P22-sensitivity. A tryptophan-requiring Salmonella typhosa – Escherichia coli hybrid, which has the unique ability to serve as recipient in transduction mediated by both P22 and P1, was used to determine if P22 and P1 adsorb at the same oroverlapping sites: (i) The adsorption of each of P1 and P22 is similar when added individually or together to the hybrid at a saturating multiplicity of infection (moi), (ii) P1 grown on trp+E. coli yields the maximum frequency of Trp+ abortive transductions at an moi of 6 with the trp hybrid recipient; the presence of increasing numbers of P22 grown on trp S. typhimrium does not decrease the number of Trp+ transduction from P1. (iii) A mixture of P1 (grown on trp+E. coli) and P22 (grown on trp+S. typhimurium) yields more abortive transductions than does P1 alone. Thus phages P1 and P22 adsorb to the hybrid cells on different sites.
Infection chronique d'Acholeplasma laidlawii par un mycoplasma virus du groupe L1
Authors: Roger Annie
Published: May 2010

Mycoplasma virus MVL 51, of the group L1 of Gourlay, has been shown to induce a chronic cell infection of two reference strains (1305/68 and JA 1) of Acholeplasma laidlawii. Titers of virus and cells remain at a fairly high level during infection, around 108 units/mL, with a mean ratio of approximately 1 PFU/1 CFU, as under control of a regulation mechanism. However, sudden spontaneous variations in the virus level do occur, from time to time, thus suggesting transient regulation breaks but not impairing the pattern of a more extensive regulation cycle.
Hyperaccumulation of zinc by zinc-depleted Candida utilis grown in chemostat culture
Authors: Lawford H. G. , Pik J. R. , Lawford G. R. , Williams T. , Kligerman A.
Published: May 2010

The steady-state levels of zinc in Candida utilis yeast grown in continuous culture under conditions of zinc limitation are <1 nmol Zn2+/mg dry weight of cells. Unlike carbon-limited cells, zinc-depleted cells from a zinc-limited chemostat possess the capacity to accumulate and store zinc at levels far in excess of the steady-state level of 4 nmol/mg dry biomass observed in carbon-limited chemostat cultures. Zinc uptake is energy-dependent and apparently unidirectional since accumulated 65Zn neither exits from preloaded cells nor exchanges with cold Zn2+. The transport system exhibits a high affinity for Zn2+ (Km = 0.36 μM) with a Vmax of 2.2 nmol per minute per milligram dry weight of cells. Growth during the period of the uptake assay is responsible for the apparent plateau level of 35 nmol Zn2+/mg dry weight of cells achieved after 20–30 min in the presence of 65Zn at pH 4.5 and 30 °C. Inhibition of growth during the uptake assay by cycloheximide results in a biphasic linear pattern of zinc accumulation where the cellular zinc is about 60 nmol/mg dry weight after 1 h. The enhanced level of accumulated zinc is not inhibitory to growth. Zinc-depleted C. utilis contains elevated amounts of polyphosphate and this anionic polymer must be considered a possible zinc-sequestering and storage agent. Present experimental evidence does not allow discrimination between possible regulation of zinc homeostasis either by inhibition of zinc efflux through control of the membrane carrier or by control of the synthesis of a cytoplasmic zinc-sequestering macromolecule.
Purification and characterization of exocellular proteases produced by a clinical isolate and a laboratory strain of Pseudomonas aeruginosa
Authors: Jensen S. E. , Phillippe L. , Tseng J. Teng , Stemke G. W. , Campbell J. N.
Published: May 2010

Exocellular protease production was examined in two separate strains of Pseudomonas aeruginosa, one a clinical isolate and the other a laboratory strain. Both strains produced two separate proteases (proteases 1 and 2) which were indistinguishable from one strain to the other. The two proteases were purified by a two-step procedure of gel filtration chromatography followed by ion-exchange chromatography. Proteases 1 and 2 were shown to be distinct serologically and unrelated by physicochemical parameters examined. Protease 1 was the major exocellular protein produced and contributed about 95% of the total protease activity of the culture. It was estimated to have a molecular weight of 34 850 and was also shown to contain 10% glucosamine by weight. Protease 2, in contrast, had an estimated molecular weight of 52750 and contained no detectable carbohydrate. Proteases 1 and 2 were both stimulated by Ca2+, and Mg2+ and inhibited by Co2+Zn2+, and 1,10-o-phenanthroline. Protease 1 was also inhibited by EDTA. In addition to protease activity, both proteases 1 and 2 demonstrated elastase activity as well as a limited collagenase activity. Specificity of the two proteases against synthetic peptides was, however, quite different. Protease 1, but not protease 2, showed a preference for peptide bonds in which the amino group was contributed by an amino acid with a hydrophobic R group.
Mechanisms of host defense and quantitative comparisons of bacterial populations in experimental peritonitis
Authors: Jennings Margaret M. , Jennings Stephen A. , Robson Martin C. , Heggers John P.
Published: May 2010

A model for the quantitative study of bacterial levels in blood, ascitic fluid, and liver, induced by Escherichia coli in the rat, has been devised. Three experimental situations were then studied: non-fatal peritonitis, fatal peritonitis induced by bacteria rendered more virulent by serial passage through test animals, and fatal peritonitis using haemoglobin adjuvant with the more virulent strain. Results indicate that a variety of defense mechanisms are operant in the host animal. In the non-fatal peritonitis, clearance of free bacteria from the peritoneum is observed with a late rebound in local and systemic populations. These phenomena correlate well with in vitro studies of bacterial uptake by peritoneal macrophages. In fatal peritonitis without adjuvant, much larger numbers of bacteria seem to escape initial clearance in the peritoneum and proximal reticuloendothelial system with resultant overwhelming septicaemia. In fatal peritonitis with adjuvant, much less clearance of organisms from the peritoneum is observed, with resultant overgrowth of bacteria and host death. It thus seems that the initial host defenses center around peritoneal clearance of introduced organisms, and that processes which interfere with this clearance prove fatal.
Nodulation of soybeans carrying the nodulation-restrictive gene, rj1, by an incompatible Rhizobium japonicum strain upon mixed inoculation with a compatible strain
Authors: Devine T. E. , Kuykendall L. D. , Breithaupt B. H.
Published: May 2010

The rj1 gene in soybeans prevents nodulation by most strains of Rhizobium japonicum. Several strains, however, are known to nodulate rj1 plants in vermiculite or sand culture. Pure broth cultures of one of these strains (61 NalR) and a strain producing the typical non-nodulating response with rj1 (I-110 ARS) were mixed and used as inoculum on Clark rj1 soybeans in a growth chamber experiment. Both strains carried drug resistance markers and were identified using selective media. Analysis of the nodules formed indicated that 32% of the nodules contained both strains, 36% contained only the usually non-nodulating strain I-110 ARS, and 32% contained the usually infective strain (61 NalR). These results indicate that under conditions of high inoculum density the roots of Clark rj1 plants did not distinguish between Rhizobium strains 61 NalR and I-110 ARS. Subsequent tests with Rhizobium isolates from the nodules containing only strain I-110 ARS indicated that these rhizobia had not undergone a permanent genetic change in nodulation potential but were infective only because of temporary association with strain 61 NalR.
Protein turnover in a moderately halophilic bacterium
Authors: Hipkiss A. R. , Armstrong D. W. , Kushner D. J.
Published: May 2010

Protein turnover was investigated in exponentially growing Vibrio costicola, a moderately halophilic bacterium that can grow in the NaCl concentration range 0.5–3.5 M (with optimal growth at about 1.0 M). In 1.0 or 1.5 M NaCl the breakdown rate of pulse-labelled proteins was about 5%/h whereas in 0.5 M NaCl breakdown was about 9%/h. These results are in contrast to those reported and observed in Escherichia coli which has a turnover rate of 1–2%/h in exponential growth. Growing E. coli in the highest possible NaCl concentration (1.0 M) did not significantly increase protein turnover. Shifting V. costicola from a higher to a lower NaCl concentration increased the rate of turnover of pulse-labelled proteins, whereas shifting it from a lower to a higher NaCl concentration decreased the rate of turnover. The critical factor in these experiments was not the NaCl concentration at which proteins were labelled but that at which the cells were subsequently incubated. The level of breakdown of long-labelled proteins was low (about 2%/h) and was not affected by shifts in NaCl concentration. Breakdown of pulse-labelled protein was inhibited by cyanide and tetracycline but not by iodoacetate, azide. or chloramphenicol. Treatment with streptomycin increased the rate of turnover. Turnover in cell-free systems was lower than in intact cells and was not inhibited by cyanide or tetracycline. It is suggested that the high rate of turnover, even at optimal NaCl concentrations, may reflect errors in protein synthesis, and that the effect of lower NaCl concentrations may be to alter "native" conformation and thus to increase the susceptibility of some of the properly made proteins to proteolysis.
Serological relationships among budding, prosthecate bacteria
Authors: Powell Delois M. , Roberson Bob S. , Weiner Ronald M.
Published: May 2010

The somatic antigens of 25 strains of budding bacteria were typed and 14 serologically distinct groups were identified, suggesting considerable antigenic diversity among hyphomicrobia. Ten of the groups were represented by a single isolate, 2 contained two isolates, 1 three isolates, and 1 eight isolates. The strains in the largest group of eight isolates each shared at least one common antigen. However, there was also considerable antigenic heterogeneity within this cluster. Serological activity resided in the lipopolysaccharide (LPS) portion of cell walls and also in a heat labile component of Hyphomicrobium neptunium. The amino acid utilizing isolates, H. neptunium and Hyphomonas polymorpha, were serologically unrelated and it is suggested that the two organisms could be grouped as members of the same genus but not the same species.
Confirmatory identification of Neisseria gonorrhoeae by slide coagglutination
Authors: Lim Daniel V. , Wall Trevor
Published: May 2010

Neisseria gonorrhoeae was identified by the Phadebact® gonococcus test, a rapid slide coagglutination technique, and the results obtained were compared with those obtained by conventional methods (Gram stain morphology, oxidase reaction, and carbohydrate utilization tests) for the confirmatory identification of gonococci. Of 308 clinical isolates examined, the coagglutination procedure correctly identified 97.8% of the isolates tested as N. gonorrhoeae and 93.9% of other bacteria as not N. gonorrhoeae. The coagglutination procedure also identified 29 laboratory strains correctly as not N. gonorrhoeae. The slide coagglutination test is easy to perform and offers a valuable alternative to other techniques for the confirmatory identification of N. gonorrhoeae.
Immunofluorescent detection of double-stranded RNA in cells infected with reovirus, infectious pancreatic necrosis virus, and infectious bursal disease virus
Authors: Macdonald Richard D.
Published: May 2010

Urea treatment of ethanol-fixed virus-infected cells exposed nucleic acid antigens for immunofluorescence. Three double-stranded (ds) RNA-containing viruses showed bright fluorescence using antibodies against dsRNA. Three single-stranded RNA-containing viruses showed less intense fluorescence with anti-dsRNA. Four out of five cell lines persistently infected with various RNA-containing viruses showed no dsRNA detectable by immunofluorescence.
Cache Valley virus: experimental infection in Culiseta inornata
Authors: Corner Linda C. , Robertson Audrei K. , Hayles Lance B. , Iversen John O.
Published: May 2010

Experiments were conducted to examine the dynamics of Cache Valley virus in Culiseta inornata, the probable chief vector of the virus. Of about 1500 laboratory reared C. inornata exposed to viraemic suckling mice, 72 took a blood meal. A relatively high percentage (93%) of the latter mosquitoes became infected. The virus increased more than 100-fold in the experimentally infected mosquitoes. The increasing viral titres were noticed after 7 days and after 15 days. Peak titres averaged 105.0 (mean suckling mouse intracerebral lethal dose) SMICLD50/0.02 mL. The infected mosquitoes had peak titres until at least 35 days after the mosquitoes ingested blood from infected suckling mice. A single transmission of virus by bite occurred 30 days after the viraemic blood meal. Transovarial transmission was demonstrated. In two experiments, 3.3 and 2.9% of infected mosquitoes transovarially transmitted Cache Valley virus to both male and female progeny. The minimum infection rate for the progeny was 2.05/1000 mosquitoes. This is the first reported experimental demonstration of transovarian transmission in a species of mosquito which overwinters as an adult. The role of transovarian transmission in the natural maintenance of Cache Valley virus remains undetermined.
Isolation of a variant of Streptococcus faecalis with enhanced barotolerance
Authors: Marquis Robert E. , Bender Gary R.
Published: May 2010

Streptococcus faecalis ATCC 9790 was adapted to grow at pressures as high as 1000 atm (1 atm = 101.325 kPa) at 37 °C by gradually increasing the growth pressure for agar stab subcultures in steps of 50 atm from 750 atm, the maximum growth pressure for unadapted cultures. A stable variant with enhanced barotolerance designated APR-11 was characterized. Similar variants could be obtained repeatedly from S. faecalis cultures by following the indicated procedure. APR-11 was able to grow in liquid media at pressures some 200 atm greater than the maximum for the parent. It appeared to have a regulatory defect in the arginine dihydrolase system and produced ammonia during glycolysis even in the presence of high concentrations of glucose. The ammonia acted to neutralize metabolic acids and to confer a type of acid tolerance. This acid tolerance may be involved in barotolerance since pressure is known to render S. faecalis hypersensitive to acid conditions. In all, it appeared that pressure can be used as a selection agent for isolation of rare barotolerant variants in normal bacterial populations.
Effects of amino acids on Thiobacillus acidophilus. II. Threonine deaminase
Authors: Proteau Gérald , Silver Marvin
Published: May 2010

Biosynthetic L-threonine deaminase was partially purified 73-fold with a 60% recovery from Thiobacillus acidophilus by ammonium sulfate fractionation and by Sepharose 6B-C1 chromatography. The optimal pH for enzyme activity was between 9.0 and 10.0 and no optimal pH shift was observed in the presence of L-isoleucine, an inhibitor. The enzyme was effectively inhibited by L-isoleucine and showed homotropic interaction only in the presence of L-isoleucine.Kinetic studies indicate that there are at least two threonine binding sites and at least two isoleucine binding sites. The Km for threonine is 2.5 × 10−3 M. The inhibition due to isoleucine is reversed by low concentrations of L-valine. L-Valine at high concentrations acts as a substrate analogue and competitively inhibits L-threonine binding at the active site; the K1 is 1.6 × 10−2 M.
Photosynthetic activities of phytoneuston and phytoplankton
Authors: Albright Lawrence J.
Published: May 2010

Numbers, biomasses, and photosynthetic activities of phytoneuston and phytoplankton of near-surface microlayer and associated sub-surface waters, respectively, of coastal British Columbia were compared. Microalgal numbers, biomasses, and photosynthetic activities were generally greater in the sub-surface waters. Photosynthetic activities per unit biomass of the phytoneuston were approximately two-thirds those of the phytoplankton. These data suggest that the phytoneuston are injured or inhibited in some manner in near-surface microlayer waters.
Chlamydia psittaci: inclusion vacuole ultrastructure
Authors: Stokes Gerald V.
Published: May 2010

The inclusion ultrastructure of fibroblasts infected with Chlamydia psittaci (6BC) was studied. Electron microscopic techniques were used which permitted the observation of whole infected host cells and 1.0-μm sectioned preparations. It was shown that the cytoplasmic inclusion vacuoles of infected cells contained interconnecting structures within which chlamydiae reproduce.
Indigenous bacteria that influence the number of Salmonella typhimurium in the spleen of intravenously challenged mice
Authors: Roach Sally , Tannock Gerald W.
Published: May 2010

Intravenous inoculation of conventional mice with 6 out of 13 bacterial strains indigenous to the mouse gastrointestinal tract led to reduced numbers of Salmonella typhimurium in the spleen following intravenous challenge with the pathogen. Gnotobiotic mice harbouring an Enterococcus in their gastrointestinal tract did not have Salmonella in the spleen following intravenous challenge. Some germfree mice or gnotobiotic mice associated with a Lactobacillus strain, in contrast, had Salmonella in the spleen following challenge.
Serological relationships among flagella of Erwinia carotovora var. atroseptica and some E. carotovora var. carotovora serogroups
Authors: Boer S. H. De
Published: May 2010

The 2 Erwinia carotovora var. atroseptica serogroups and 2 out of 16 E. carotovora var. carotovora serogroups previously established on the basis of diffusible somatic antigens were shown to be serologically related by agglutination procedures using whole cells. The common agglutinating antigen in serogroups I, III, V, and XVIII was heat labile and identified as the bacterial flagella by the fluorescent antibody staining procedure. A few strains in serogroups I and III apparently lacked flagella altogether. Fluorescent antibody staining of whole cells also confirmed that the cell wall antigens of serogroups I, II, and XVIII were related and that the cell wall antigens of serogroups III and V were not related to each other or to the other serogroups.
Composition of Methanospirillum hungatii GP1 during growth on different media
Authors: Breuil C. , Patel G. B.
Published: May 2010

Growth of Methanospirillum hungatii GP1 as determined by optical density measurement was comparable to growth assessed by cell dry weight, ribonucleic acid content, and deoxyribonucleic acid content. Cultivation of M. hungatii on synthetic medium containing mineral salts, vitamins, and acetic acid indicated that, on a dry weight basis, cell constituents such as protein (71%), ribonucleic acid (15.8%), deoxyribonucleic acid (1.6%), and total carbohydrate (3.2%) did not vary significantly with the growth phase. Cells grown in the synthetic medium supplemented with yeast extract and tryptone had slightly higher protein content (76%), but the concentrations of the other cell constituents were similar and did not fluctuate much during growth. Nitrogen limiting growth resulted in somewhat lower ribonucleic acid content as well as slightly higher protein content than that in cells grown in nonlimiting medium. Methanospirillum hungatii did not accumulate any of the commonly known reserve materials under nitrogen or carbon and hydrogen limiting growth.
Improved antiserum agar method for the serogroup differentiation of Neisseria meningitidis Y and W135
Authors: Ashton F. E. , Ryan A. , Diena B. B.
Published: May 2010

Rabbit antisera prepared to meningococcal serogroups Y and W135 strains were compared with horse antisera using the antiserum agar method (ASA) for the serogroup identification of Neisseria meningitidis. Thirty-seven group Y strains formed immunoprecipitates with the Y rabbit serum only, whereas the same Y strains formed immunoprecipitates with both the Y and W135 horse antisera. Forty-seven W135 strains formed specific immunoprecipitates with both the rabbit and horse W135 antisera by ASA. None of the 166 meningococcal isolates, representative of other meningococcal serogroups, formed immunoprecipitates with the groups Y and W135 rabbit or horse antisera. Use of specific Y and W135 rabbit antisera in ASA provides an improved technique for the serogroup differentiation of groups Y and W135 meningococci.
Cell membrane phospholipids and their constituent fatty acids in dividing and nondividing cells of Micrococcus lysodeikticus
Authors: Johnson John H. , Grula E. A.
Published: May 2010

Changes occurring in the cell membrane of nondividing cells of Micrococcus lysodeikticus disIIp+ grown in the presence of the mucopeptide synthesis inhibitor D-cycloserine include (a) an increase in the relative amount of diphosphatidylglycerol with a concomitant decrease in the relative content of phosphatidylglycerol, (b) a small increase in the relative palmitic acid content of phosphatidylinositol, and (c) leakage of membrane components into the growth medium. Growth of the organism in the presence of both D-cycloserine and D-alanine (which prevents the effects of D-cycloserine on cell division and mucopeptide synthesis) prevents the above changes in the cell membrane, demonstrating that secondary damage to the cell membrane can occur as a result of inhibition in mucopeptide synthesis. Growth of the organism in the presence of D-cycloserine and pantoyl lactone prevents the leakage of membrane components and cell division inhibition. Possible relationships of these changes to cell division are discussed.
Differential effect of glucose and fructose on spore germination in the fission yeast, Schizosaccharomyces pombe
Authors: Shimoda Chikashi
Published: May 2010

Germination of isolated spores of Schizosaccharomyces pombe, measured by loss of refractility and of resistance to ethanol, was induced in a simple solution of glucose. The subsequent outgrowth steps (swelling and germ-tube formation), however, did not occur in the glucose solution. Normal outgrowth required almost all nutrients essential to vegetative growth. Germination was also induced by sucrose and mannose but only weakly by fructose. Glucose-germinated spores normally outgrew in the fructose-containing nutrient medium. Generation of CO2 from exogenous fructose by ungerminated spores was only 10% of that from exogenous glucose. These facts suggested that ungerminated spores were defective in the ability to utilize fructose and that germinated spores acquired this ability.
Growth characteristics, effects of temperature, and ion specificity of the halotolerant bacterium Halomonas elongata
Authors: Vreeland R. H. , Martin E. L.
Published: May 2010

The genus Halomonas (type species H. elongata) is a new bacterial genus composed of salt tolerant bacteria. The growth characteristics and morphology of the type strain of this bacterial group were studied using both complex and defined media. The salt tolerance of the bacterium decreased significantly on defined medium, suggesting that the type of growth medium used has a great effect on bacterial salt tolerance. Experiments on the effect of temperature on salt tolerance indicate that a temperature of 30 °C permits the greatest salt tolerance. In all of these experiments 0.375 and 1.37 M NaCl yielded the most rapid growth rates while 1.37 and 2.5 M NaCl permitted the greatest temperature tolerance. The Halomonas strain was found to have an absolute requirement for the Na+ cation. While NaNO3 and NaBr would substitute for NaCl in the growth medium, when LiCl, NH4Cl, MgCl2∙6H2O, or KCl was substituted for NaCl, the medium would not support growth. The bacterium consistently retained its rod shape regardless of the NaCl concentration in both complex and defined media. The data indicate that even though this bacterium has been in culture for over 5 years it is still well adapted to life in its natural environment.
An improved selective and diagnostic medium for the isolation and enumeration of Bacillus cereus in foods
Authors: Holbrook R. , Anderson Judith M.
Published: May 2010

The use and performance of an improved diagnostic and selective medium, PEMBA (polymyxin pyruvate egg yolk mannitol bromothymol blue agar), for the detection of Bacillus cereus in foods is described. The distinct colonial appearance of B. cereus on PEMBA permitted the recognition of both strains: those that do precipitate egg yolk and those that do not react with egg yolk. A staining procedure, used to demonstrate microscopically both the presence of lipid globules in vegetative cells and spore morphology of isolates, proved a rapid and reliable confirmatory test which gave complete agreement with a battery of biochemical tests used for this purpose. The quantitative recovery of B. cereus on PEMBA from 143 food samples was not significantly different from counts on KG (Kim and Goepfert), MYP (mannitol egg yolk phenol red), and McClung's media, and the selectivity of PEMBA was generally superior.
The effect of growth temperature on the lipid composition and differentiation of Dictyostelium discoideum
Authors: Das D. V. Mohan , Herring F. G. , Weeks Gerald
Published: May 2010

The growth temperature of the axenic strain of Dictyostelium discoideum, Ax-2, influences its subsequent rate of development. Despite the fact that many other microorganisms exhibit homeoviscous adaptation in response to temperature, the altered rates of D. discoideum development are not due to a response to modified membrane fluidity. Growth temperature does not affect the fluidity of the cell membranes as determined by electron paramagnetic resonance and there are no systematic temperature dependent variations in fatty acid composition or sterol:phospholipid ratio.
The influence of increasing numbers of nonindicator organisms upon the detection of indicator organisms by the membrane filter and presence–absence tests
Authors: Clark James A.
Published: May 2010

Municipal water samples were analyzed by membrane filter (MF) procedures for total coliforms, "background" counts, and 24-and 48-h, 35 °C plate counts. Presence–absence (P–A) tests were done on the samples for total coliforms and other indicator bacteria. The frequency of detection of indicator organisms by P–A tests was better than twice that recovered by MF analyses. When the 24-h plate count data were grouped into counting ranges of 0, 1–100, 101–1000, and > 1000, a marked inhibition effect was observed with total coliform MF recoveries on samples producing plate counts > 1000/mL. When the "background" and 48-h plate count results were placed in the corresponding counting ranges, inhibition of indicator organisms in the total coliform MF analyses was not observed. No inhibition effect was observed in the recovery of indicator organisms by P–A tests at any of the counting range levels. The presence of an apparent inhibition effect by high numbers of bacteria in a sample was shown to be influenced by the incubation period and type of count parameter, as well as the isolation technique for detection of indicator organisms.
Formation and identification of novel N-conjugates of p-chloroamphetamine by Mycobacterium smegmatis
Authors: Coutts Ronald T. , Foster Brian C. , Pasutto Franco M.
Published: May 2010

(+)-p-Chloroamphetamine was readily N-conjugated by Mycobacterium smegmatis and the products obtained were identified by gas–liquid chromatography and mass spectrometry. Formation of the N-conjugation products was dependent upon the history of the culture. Revitalized lyophilates mediated formation of two acetoin derived p-chloroamphetamine N-conjugates, the Schiff base 4-chloro-α-methyl-N-(1-methylacetonylidine)benzeneethanamine and 4-chloro-α-methyl-N-(1-methylacetonyl)benzeneethanamine. After several subcultures, these products were no longer detected and N-acetyl-p-chloroamphetamine was the only metabolite detected. Mycobacterium smegmatis metabolism of amphetamine was also studied. The metabolic products were analogous to those obtained from p-chloroamphetamine.
Presence of cytochrome b in Nitrobacter agilis
Authors: Chaudhry Ghulam R. , Lees Howard , Suzuki Isamu
Published: May 2010

The presence of a b-type cytochrome in Nitrobacter agilis was demonstrated by its isolation in DEAE-cellulose chromatography and the pyridine protohemochrome derivative. This b-type cytochrome was autoxidizable and reacted with NO2− and CO.
Regulatory control of 3-deoxy-D-arabino-heptulosonic acid 7-phosphate synthetase in Streptomyces antibioticus
Authors: Murphy Michael F. , Katz Edward
Published: May 2010

Streptomyces antibioticus possesses a tryptophan-inhibitable 3-deoxy-D-arabino-heptulosonic acid 7-phosphate (DAHP) synthetase whose synthesis is also repressed by L-tryptophan. Studies of the DAHP synthetase obtained by ammonium sulfate fractionation of a crude extract derived from S. antibioticus revealed that the enzymic activity was only partially inhibited by tryptophan. Inhibition of the DAHP synthetase activity was strongly pH dependent at values below 7.0. A number of tryptophan analogues was noted to inhibit the enzyme; by contrast, other aromatic amino acid end products failed to affect DAHP synthetase activity. Chorismic acid, a key intermediate in aromatic amino acid biosynthesis, was ineffective as an inhibitor when used alone; however, if supplied with L-tryptophan, a further reduction of DAHP synthetase activity (15–25%) was routinely observed.
Cyclic adenosine 3′,5′-monophosphate binding protein in developing myxospores of Myxococcus xanthus
Authors: Orlowski Michael
Published: May 2010

The interaction of cyclic adenosine 3′,5′-monophosphate (cAMP) with specific protein molecules was examined in the high-speed supernatant fraction of extracts made at stages throughout glycerol-induced myxospore development in Myxococcus xanthus. Experiments using 8-azido[32P]cAMP, a photoaffinity analogue of cAMP, and SDS – polyacrylamide gel electrophoresis showed that the nucleotide interacts with only a single protein band of 12 500 molecular weight. Both the identiy and amount of this protein remained constant throughout development. The binding protein was specific for cAMP; other nucleotides did not compete with cAMP for binding sites. A Scatchard analysis showed evidence of only a single class of binding sites with a high affinity for cAMP.
Microbiological water and effluent sample preservation
Authors: Dutka B. J. , El-Shaarawi A.
Published: May 2010

A study, using four types of water samples ranging from relatively pure stream water to water containing industrial and domestic effluents, was carried out to investigate the effect of storage temperature on four bacterial parameters: total coliform, fecal coliform, fecal streptococcus, and heterotrophic bacteria. In the study, each water sample was cooled immediately after collection to approximately 1.5 °C by storage in crushed ice. At 2-, 24-, 30-, and 48-h intervals, the sample was mixed, and a subsample was removed and tested. Three separate analyses for each parameter were made on each subsample. The data available for statistical analyses contained, in some cases, the values obtained for the three subsamples and, in others, the means of the three values. The data were analysed as replicated data and as part of the entire set. The analysed data indicated (i) that with the exception of heterotrophic populations, more than 75% of the samples were microbiologically stable for at least 24 h, (ii) that at least 50% of samples tested for heterotrophic densities were stable for a minimum period of 24 h, (iii) that the original water temperature and bacterial load do not appear to be consistent factors in the preservation of samples for microbiological analysis, and (iv) that nutrient levels, also, do not seem to be consistent factors in the preservation of water samples for microbiological analyses.
Sorogen elongation and side branching during fruiting body development in Polysphondylium pallidum
Authors: O'Day Danton H. , Durston Antony J.
Published: May 2010

We report a cinematographic analysis of culmination in fruiting bodies of Polysphondylium pallidum. During the final stages of aggregation, sorogen elongation is slow. An increase in the rate of sorogen elongation occurs when the growing stalk contacts the substratum, lifting the cell mass into the air. The elongation process slows and finally stops as differentation of the terminal spore mass occurs. During the rapid elongation phase, variations in the rate of elongation of the main cell mass are correlated with the process of side branching. Side-branch elongation resembles elongation of the main sorogen with the rate of elongation increasing as the side-branch stalk contacts the main stalk and slowing as spore differentiation occurs. The morphological events of branching have been studied in detail and models to explain this process are discussed.
Chemical and enzymatic changes in the cell walls of Candida albicans and Saccharomyces cerevisiae by scanning electron microscopy
Authors: Koch Yvonne , Rademacher K. H.
Published: May 2010

Candida albicans and Saccharomyces cerevisiae cells were examined by scanning electron microscopy before and after extraction of the mannans of the cell wall. The surfaces of control cells were smooth; after mannan extraction they were rough and showed erosions which were particularly striking within the area of the scars. Helicase digested irregular holes through the cell wall within 20 min; these increased in size during an additional 40 min of digestion. These holes were not localized in or on the bud scars, which remained intact even after the long digestion period. The results were used to construct a model for yeast cell wall structure.
Evidence that associated soil bacteria may influence root hair infection of actinorhizal plants by Frankia
Authors: Knowlton Susan , Berry Alison , Torrey John G.
Published: May 2010

Nodulation of actinorhizal plants (Alnus rubra Bong. and others) by isolated Frankia strains occurred either at a low frequency or not at all under axenic conditions. But nodulation was achieved under nonsterile conditions and four strains of bacteria were isolated which promoted nodulation when plants were inoculated with the bacteria plus Frankia. Four strains of Psendomonas cepacia also promoted nodulation. Root hair deformation occurred when roots of A. rubra were inoculated with these bacterial isolates, or with the bacteria plus Frankia, but rarely or not at all when roots were inoculated with the actinomycete alone. The nonendophytic bacterial strains were not detected within the nodule tissue. It is proposed that the bacterial isolates aid in the infection process at the host root hair surface, by causing root hair deformation; this may allow intimate contact between the Frankia filament and the hair wall.
Isozymes of α-galactosidase from Bacillus stearothermophilus
Authors: Pederson Dennis M. , Goodman Richard E.
Published: May 2010

Two molecular forms of α-galactosidase (EC 3.2.1.22) synthesized constitutively by Bacillus stearothermophilus, strain AT-7, have been purified. α-Galactosidase I (with the substrate p-nitrophenyl α-D-galactopyranoside (PNPG)) has a pH optimum of 6 and a half-life at 65 °C of > 2 h at low protein concentration. α-Galactosidase II has a pH optimum of 7 with PNPG and a half-life at 65 °C of about 3 min. The isozymes also differ with respect to their Km with PNPG and melibiose. Both enzymes are inhibited competitively by D-galactose, melibiose, and Tris. With the β-glycosides cellobiose and lactose either noncompetitive or mixed-type inhibition is observed, with the pattern dependent on both the pH and the isozyme. The two isozymes have similar Arrhenius activation energies (about 20 kcal/mol, 1 kcal = 4.184 kJ). Their molecular weights, estimated by disc gel electrophoresis, are α-galactosidase I, 280 000 ± 30 000 and α-galactosidase II, 325 000 ± 15 000. Dodecyl sulfate gel electrophoresis gave a single band for each enzyme. The respective molecular weights, 81 000 + 500 for α-galactosidase I and 84 000 ± 500 for α-galactosidase II, suggest that both enzymes consist of four subunits.
Etude comparative des caractères biochimiques de tréponèmes hémolytiques isolés du porc
Authors: Picard Benoit , Lariviere Serge , Saheb Samir A.
Published: May 2010

A number of hemolytic strains of treponemes were isolated from normal pigs and pigs which died of swine dysentery. According to their hemolytic pattern, these strains can be differentiated into strongly β-hemolytic and weakly β-hemolytic. According to Kinyon and Harris, aside from enteropathogenicity and hemolytic pattern, both fructose fermentation and indole production are the characteristics used in separating the two groups of treponemes. Our comparative study of these two groups of strains shows that while the fermentation activity is low for the strongly β-hemolytic strains it is high for the weakly β-hemolytic strains. The latter constitutes a heterogenous group which, contrary to Kinyon and Harris, can only be differentiated from the other strains by their ability to ferment lactose and to produce isovaleric acid in glucose supplemented broth.
Electrophoretic analysis of Clostridium botulinum types A and B hemagglutinins
Authors: DasGupta Bibhuti R.
Published: May 2010

The serologically related hemagglutinins of Clostridium botulinum types A and B were resolved into several bands in polyacrylamide gels in the presence of sodium dodecyl sulfate. Reduction of the samples with mercaptoethanol partly changed the band patterns, but with each hemaglutinin the two fastest moving bands in the reduced and unreduced samples were the same. In type A these two smallest units were of molecular weight 14 500 and 19 500; in type B they were of molecular weight 14 500 and 20 000. The experimentally determined molecular weight of the other resolved units agreed with those calculated on the basis that they were aggregations of the two smallest units in varying but whole multiples.