bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction of fMet‐tRNAfMetand fMet‐AMP with the C‐terminal domain ofThermus thermophilustranslation initiation factor 2
Authors: Szkaradkiewicz Karol , Zuleeg Tilman , Limmer Stefan , Sprinzl Mathias 
Published: October 2003

Two polypeptides resistant against proteolytic digestion were identified inThermus thermophilustranslation initiation factor 2 (IF2): the central part of the protein (domains II/III), and the C‐terminal domain (domain IV). The interaction of intact IF2 and the isolated proteolytic fragments with fMet‐tRNAfMetwas subsequently characterized. The isolated C‐terminal domain was as effective in binding of the 3′ end of fMet‐tRNAf Metas intact IF2. N‐Formylation of Met‐tRNAfMetwas required for its efficient binding to the C‐terminal domain. This suggests that the interaction between the C‐terminal domain and the 3′ end of fMet‐tRNAfMetis responsible for the recognition of fMet‐tRNAfMetby IF2 during translation initiation. Moreover, it was demonstrated that fMet‐AMP is a minimal ligand of IF2. fMet‐AMP inhibits fMet‐tRNAfMetbinding to IF2 as well as the activity of IF2 in the stimulation of ApUpG‐dependent ribosomal binding of fMet‐tRNAf Met. Specific interaction of fMet‐AMP with IF2 was demonstrated by1H‐NMR spectroscopy.These findings indicate that fMet‐AMP and the 3′ terminal fMet‐adenosine of fMet‐tRNAfMetuse the same binding site on the C‐terminal domain of IF2 and imply that the interaction between the C‐terminal domain and the 3′ end of fMet‐tRNAfMetis primarily responsible for the fMet‐tRNAfMetbinding and recognition by IF2.
Effect of growth temperature on cellular fatty acids in sulphate‐reducing bacteria
Authors: Könneke Martin , Widdel Friedrich 
Published: October 2003

SummaryThe effect of growth temperature on the cellular fatty acid composition of sulphate‐reducing bacteria (SRB) was studied in 12 species belonging to eight genera including psychrophiles and mesophiles. Most of these species were of marine origin. The investigated SRB with the exception of four Desulfobacter species exhibited only a minor increase in the proportion of cis‐unsaturated fatty acids (by ≤5% per 10°C) when the growth temperature was decreased; psychrophiles maintained their typically high content of cis‐unsaturated fatty acids (around 75% of total fatty acids) nearly constant. The four Desulfobacter species, however, increased the proportion of cis‐unsaturated among total fatty acids significantly (by ≥14% per 10°C; measured in late growth phase) with decreasing growth temperature. The ratio between unsaturated and saturated fatty acids in Desulfobacter species changed not only with the growth temperature, but also with the growth state in batch cultures at constant temperature. Changes of cellular fatty acids were studied in detail with D. hydrogenophilus, the most psychrotolerant (growth range 0–35°C) among the mesophilic SRB examined. Desulfobacter hydrogenophilus also formed cis‐9,10‐methylenehexadecanoic acid (a cyclopropane fatty acid) and 10‐methylhexadecanoic acid. At low growth temperature (12°C), the relative amount of these fatty acids was at least threefold lower; this questions the usefulness of 10‐methylhexadecanoic acid as a reliable biomarker of Desulfobacter in cold sediments.
Indigenous and contaminant microbes in ultradeep mines
Authors: Onstott T. C. , Moser D. P. , Pfiffner S. M. , Fredrickson J. K. , Brockman F. J. , Phelps T. J. , White D. C. , Peacock A. , Balkwill D. , Hoover R. , Krumholz L. R. , Borscik M. , Kieft T. L. , Wilson R. 
Published: October 2003

SummaryRock, air and service water samples were collected for microbial analyses from 3.2 kilometres depth in a working Au mine in the Witwatersrand basin, South Africa. The ∼ metre‐wide mined zone was comprised of a carbonaceous, quartz, sulphide, uraninite and Au bearing layer, called the Carbon Leader, sandwiched by quartzite and conglomerate. The microbial community in the service water was dominated by mesophilic aerobic and anaerobic, α‐, β‐ and γ‐Proteobacteria with a total biomass concentration ∼104 cells ml−1, whereas, that of the mine air was dominated by members of the Chlorobi and Bacteroidetes groups and a fungal component. The microorganisms in the Carbon Leader were predominantly mesophilic, aerobic heterotrophic, nitrate reducing and methylotrophic, β‐ and γ‐Proteobacteria that were more closely related to service water microorganisms than to air microbes. Rhodamine WT dye and fluorescent microspheres employed as contaminant tracers, however, indicated that service water contamination of most of the rock samples was < 0.01% during acquisition. The microbial contaminants most likely originated from the service water, infiltrated the low permeability rock through and accumulated within mining‐induced fractures where they survived for several days before being mined. Combined PLFA and terminal restriction fragment length profile (T‐RFLP) analyses suggest that the maximum concentration of indigenous microorganisms in the Carbon Leader was < 102 cells g−1. PLFA, 35S autoradiography and enrichments suggest that the adjacent quartzite was less contaminated and contained ∼103 cells gram−1 of thermophilic, sulphate reducing bacteria, SRB, some of which are δ‐Proteobacteria. Pore water and rock geochemical analyses suggest that these SRB′s may have been sustained by sulphate diffusing from the adjacent U‐rich, Carbon Leader where it was formed by radiolysis of sulphide.
Distribution of chloropigments in suspended particulate matter and benthic microbial mat of a meromictic lake, Lake Kaiike, Japan
Authors: Nakajima Yoji , Okada Hisatake , Oguri Kazumasa , Suga Hisami , Kitazato Hiroshi , Koizumi Yoshikazu , Fukui Manabu , Ohkouchi Naohiko 
Published: October 2003

SummaryWe investigated the distribution of chloropigments in a small meromictic lake, Lake Kaiike, south‐west Japan. In the water‐column, concentrations of Chl a related to cyanobacteria, BChl a related to purple sulphur bacteria, and three types of BChl e homologues (BChls e1, e2 and e3) related to brown‐coloured green sulphur bacteria, were maximal at the redox boundary. Below the redox boundary, absolute concentrations of Chl a and BChl a gradually decreased with depth, whereas BChls e remained rather constant. Suspended particulate matter (SPM) at the deeper region of the anoxic water‐column was enriched in highly alkylated BChl e homologues compared with SPM at the redox boundary. The shift in the relative content of highly alkylated BChl e homologues beneath the boundary was associated with community related adaptation of brown‐coloured green sulphur bacteria to changes in light quality/quantity, resulting from the optical absorption and reflectance of SPMs in the overlying water‐column. Benthic microbial mats were characterized by high abundances of BChls e, in which highly alkylated homologues were substantially abundant. This suggests that the BChls e in the microbial mat may be derived from the low‐light adapted brown‐coloured green sulphur bacteria forming the bacterial mat.
Serum Vitamin D and Falls in Older Women in Residential Care in Australia
Authors: Flicker Leon , Mead Kate , MacInnis Robert J. , Nowson Caryl , Scherer Sam , Stein Mark S. , Thomasx Jennifer , Hopper John L. , Wark John D. 
Published: October 2003

Objectives: To determine the prevalence of vitamin D deficiency in older people in residential care and the influence that the level of vitamin D may have on their incidence of falls.Design: Prospective cohort.Setting: Residential care facilities for older people in several states of Australia.Participants: Six hundred sixty‐seven women in low‐level care and 952 women in high‐level care, mean age 83.7 years.Measurements: Serum 25‐hydroxyvitamin D (25D) levels and recognized risk factors for falls including current medication use, a history of previous fractures, weight, tibial length (as a surrogate for height), cognitive function, walking ability, and frequency of going outdoors were determined. The women in low‐level care and high‐level care were followed for an average of 145 and 168 days, respectively. Falls were recorded prospectively in diaries completed monthly by residential care staff.Results: Vitamin D deficiency (defined as a serum 25D level below 25 nmol/L) was present in 144 (22%) women in low‐level care and 428 (45%) in high‐level care. After excluding 358 bed‐bound residents and adjusting for weight, cognitive status, psychotropic drug use, previous Colles fracture, and the presence of wandering behavior, log serum 25D level remained independently associated with time to first fall. The adjusted hazards ratio was 0.74 (95% confidence interval=0.59–0.94; P=.01), implying a 20% reduction in the risk of falling with a doubling of the vitamin D level.Conclusion: Vitamin D deficiency is common in residential care in Australia. A low level of serum vitamin D is an independent predictor of incident falls.
RBC alloimmunization and autoimmunization among transfusion‐dependent Arab thalassemia patients
Authors: Ameen Reem , Al‐Shemmari Salem , Al‐Humood Salah , Chowdhury Rafiq I. , Al‐Eyaadi Ohood , Al‐Bashir Abdulaziz 
Published: October 2003

BACKGROUND:  Thalassemia major is a common hemoglobinopathy in the Arabian Gulf region. However, limited data are available on the frequency of RBC alloimmunization and autoimmunization in transfusion‐dependent Arab thalassemia patients.STUDY DESIGN AND METHODS:  A total of 190 thalassemia major patients were classified as Kuwaiti Arab and non‐Kuwaiti Arab. Pretransfusion investigation records were reviewed for the presence of RBC alloantibody and autoantibody, and the age at which RBC alloantibody was developed.RESULTS:  Fifty‐seven (30%) patients developed RBC alloantibodies. The most common clinically significant alloantibodies were directed against antigens in the Kell and Rh systems. Anti‐K developed in 41 (72%) patients followed by anti‐E in 26 (45.6%). RBC autoantibodies developed in 21 (11%) patients with and without underlying RBC alloantibodies. Sixty‐six (49.6%) RBC alloantibodies developed between the ages of 2 and 10 years.CONCLUSION:  Several factors might have contributed to the high alloimmunization and autoimmunization rate observed in this study, including the heterogeneity of the population living in Kuwait, lack of better‐matched donors for those patients, and the use of poststorage leukodepleted blood. It is recommended that thalassemia patients receive blood matched for Rh and Kell antigens and prestorage leukodepleted RBCs.
Weakening or loss of antibody reactivity after prewarm technique
Authors: Leger Regina M. , Garratty George 
Published: October 2003

BACKGROUND:  The prewarm (PW) technique is a popular approach to determine whether cold antibodies are reacting at 37°C or to detect potentially clinically significant antibodies in the presence of cold autoantibodies. The PW technique has been criticized because of unexpected loss of antibody reactivity and inappropriate use of the method.STUDY DESIGN AND METHODS:  Sera containing 94 antibodies were tested by routine and PW PBS‐, LISS‐, and PEG‐IAT. LISS‐IAT was also compared to PW PBS‐IAT. Sera were also tested to determine the role of low‐affinity antibodies in loss of reactivity by PW methods.RESULTS:  PW PBS‐IAT and PW LISS‐IAT showed that 40 and 47 percent of antibodies were weakened, respectively, compared to LISS‐IAT; reactivity for 14 percent of antibodies was completely lost by each PW method. By PW PBS‐IAT, 34 percent of antibodies were weakened compared to PBS‐IAT. PW PEG‐IAT showed weakened reactivity by 56 percent of antibodies compared to PEG‐IAT; reactivity of seven out of seven PEG‐dependent antibodies was completely lost. Of 67 antibodies, 19 percent were defined as low affinity. Of 64 samples tested by the PW method and for low‐affinity antibodies, only 6 of 30 that showed decreased reactivity by the PW method appeared to be due to low‐affinity antibodies; only 6 of 12 samples that appeared to contain low‐affinity antibodies also showed decreased reactivity by the PW method.CONCLUSION:  Antibody reactivity of potentially clinically significant antibodies can be decreased or missed by PW methods. Antibody enhancement media does not ensure antibody detection by PW methods.
The matrix protein pp65341‐350: a peptide that induces ex vivo stimulation and in vitro expansion of CMV‐specific CD8+ T cells in subjects bearing either HLA‐A*2402 or A*0101 allele
Authors: Provenzano Maurizio , Lim Jong‐Baeck , Mocellin Simone , Monsurro Vladia , Bettinotti Maria , Marincola Francesco M. , Stroncek David F. 
Published: October 2003

BACKGROUND:  The stimulation of PBMNCs with HLA Class I restricted synthetic peptides derived from CMV phosphorylated matrix protein 65 (pp65) evokes CMV‐specific cytotoxic T lymphocyte (CTL) activity, a necessary condition for initiating adoptive immunotherapy against CMV‐related diseases in immune‐compromised patients. It was previously demonstrated that the CMV decamer (10‐mer) peptide pp65341‐350, QYDPVAALFF, was able to induce CMV‐specific CTLs in HLA‐A*2402 CMV‐seropositive individuals.STUDY DESIGN AND METHOD:  We investigated the ability of the peptide pp65341‐350 to reactivate memory CD8+ T cells in CMV‐seropositive subjects bearing either the HLA‐A24 or A1 allele. CTL responses were measured by IFN‐γ mRNA expression and IFN‐γ protein production as well as cytotoxic activity.RESULTS:  In this study it was found that peptide pp65341‐350 induced a specific reactivation of memory CD8+ T cells from CMV‐seropositive donors expressing either HLA‐A*2402 and/or HLA‐A*0101. Moreover, a pp65341‐350‐specific selection and expansion using PBMNCs of CMV‐seropositive donors bearing both HLA‐A*2402 and HLA‐A*0101 alleles produced cytotoxic CTLs to both HLA‐A24 and A1 peptide‐pulsed and autologous CMV‐infected target cells.CONCLUSION:  The results demonstrate that pp65341‐350 induced a specific CTL activity at both molecular and protein levels and that the peptide is specifically processed, presented, and recognized by subjects bearing HLA‐A*2402 and/or A*0101. These findings suggest that it may be possible to use this single immune dominant peptide to induce and expand CMV‐reactive CTLs for the treatment of individuals with both HLA‐A24 and A1 types.
Groove-binding unsymmetrical cyanine dyes for staining of DNA: syntheses and characterization of the DNA-binding
Authors: Karlsson H. Jonas , Eriksson Maja , Perzon Erik , Åkerman Björn , Lincoln Per , Westman Gunnar 
Published: October 2003

Abstract
Two new crescent-shaped unsymmetrical cyanine dyes have been synthesised and their interactions with DNA have been investigated by different spectroscopic methods. These dyes are analogues to a minor groove binding unsymmetrical cyanine dye, BEBO, recently reported by us. In this dye, the structure of the known intercalating cyanine dye BO was extended with a benzothiazole substituent. To investigate how the identity of the extending heterocycle affects the binding to DNA, the new dyes BETO and BOXTO have a benzothiazole group and a benzoxazole moiety, respectively. Whereas BEBO showed a heterogeneous binding to calf thymus DNA, linear and circular dichroism studies of BOXTO indicate a high preference for minor groove binding. BETO also binds in the minor groove to mixed sequence DNA but has a contribution of non-ordered and non-emissive species present. A non-intercalative binding mode of the new dyes, as well as for BEBO, is further supported by electrophoresis unwinding assays. These dyes, having comparable spectral properties as the intercalating cyanine dyes, but bind in the minor groove instead, might be useful complements for staining of DNA. In particular, the benzoxazole substituted dye BOXTO has attractive fluorescence properties with a quantum yield of 0.52 when bound to mixed sequence DNA and a 300-fold increase in fluorescence intensity upon binding.
Cash Flow Immediacy and the Value of Investment Timing
Authors: Boyle Glenn W. , Guthrie Graeme A. 
Published: October 2003

AbstractIn a model with stochastic interest rates, irreversible investment, and two investment dates, the value of investment delay has two components: the expected gain from committing now to investment at a future date and the potential gain from the ability to reverse this commitment. Holding net present value constant, we show that the values of both these components are increasing in the proportion of project cash flows that accrue in the more distant future. Our results emphasize the importance of the interaction between cash flow immediacy and interest rate uncertainty for the optimal investment policy.
Mitochondrial and Metabolic Effects of Nucleoside Reverse Transcriptase Inhibitors (NRTIs) in Mice Receiving One of Five Single- and Three Dual-NRTI Treatments
Authors: Note Reine , Maisonneuve Caroline , Lettéron Philippe , Peytavin Gilles , Djouadi Fatima , Igoudjil Anissa , Guimont Marie-Christine , Biour Michel , Pessayre Dominique , Fromenty Bernard 
Published: October 2003

ABSTRACTAlthough treatments with nucleoside reverse transcriptase inhibitors (NRTIs) can modify fat metabolism and fat distribution in humans, the mechanisms of these modifications and the roles of diverse NRTIs are unknown. We studied the mitochondrial and metabolic effects of stavudine (d4T), zidovudine (AZT), didanosine (ddI), lamivudine (3TC), zalcitabine (ddC), and three combinations (AZT-3TC, d4T-3TC, and d4T-ddI) in mice treated for 2 weeks with daily doses equivalent to the human dose per body area. Concentrations of AZT and d4T in plasma were lower when these drugs were administered with 3TC or ddI. Whatever the treatment, mitochondrial DNA was not significantly decreased in muscle, heart, brain, or white adipose tissue but was moderately decreased in liver tissue after the administration of AZT, 3TC, or d4T alone. Blood lactate was unchanged, even when NRTIs were administered at supratherapeutic doses. In contrast, the level of plasma ketone bodies increased with the administration of AZT or high doses of d4T but not with ddC, 3TC, or ddI, suggesting that the thymine moiety could be involved. Indeed, the levels of plasma ketone bodies increased in mice treated with β-aminoisobutyric acid, a thymine catabolite. Treatment with AZT, d4T, or β-aminoisobutyric acid increased hepatic carnitine palmitoyltransferase I (CPT-I) mRNA expression and the mitochondrial generation of ketone bodies from palmitate. In conclusion, therapeutic doses of NRTIs have no or moderate effects on mitochondrial DNA and no effects on plasma lactate in mice. However, AZT and high doses of d4T increase the levels of hepatic CPT-I, mitochondrial fatty acid β-oxidation, and ketone bodies, and these catabolic effects are reproduced by β-aminoisobutyric acid, a thymine metabolite.
CesRK, a Two-Component Signal Transduction System in
Listeria monocytogenes
, Responds to the Presence of Cell Wall-Acting Antibiotics and Affects β-Lactam Resistance
Authors: Kallipolitis Birgitte H. , Ingmer Hanne , Gahan Cormac G. , Hill Colin , Søgaard-Andersen Lotte 
Published: October 2003

ABSTRACT

Listeria monocytogenes
is a food-borne pathogen that can cause a variety of illnesses ranging from gastroenteritis to life-threatening septicemia. The β-lactam antibiotic ampicillin remains the drug of choice for the treatment of listeriosis. We have previously identified a response regulator of a putative two-component signal transduction system that plays a role in the virulence and ethanol tolerance of
L. monocytogenes
. Here we present evidence that the response regulator, CesR, and a histidine protein kinase, CesK, which is encoded by the gene downstream from
cesR
, are involved in the ability of
L. monocytogenes
to tolerate ethanol and cell wall-acting antibiotics of the β-lactam family. Furthermore, CesRK controls the expression of a putative extracellular peptide encoded by the
orf2420
gene, located immediately downstream from
cesRK.
Inactivation of
orf2420
revealed that it contributes to ethanol tolerance and pathogenesis in mice. Interestingly, we found that transcription of
orf2420
was strongly induced by subinhibitory concentrations of various cell wall-acting antibiotics, ethanol, and lysozyme. The induction of
orf2420
expression was abolished in the absence of CesRK. Our data suggest that CesRK is involved in regulating aspects of the cell envelope architecture and that changes in cell wall integrity provide a potent stimulus for CesRK-mediated regulation. These results further our understanding of how
L. monocytogenes
senses and responds to antibiotics that are used therapeutically in the treatment of infectious diseases.
Synthesis, Degradation, and Antimicrobial Properties of Targeted Macromolecular Prodrugs of Norfloxacin
Authors: Roseeuw Eveline , Coessens Veerle , Balazuc Anne-Marie , Lagranderie Micheline , Chavarot Pierre , Pessina Augusto , Neri Maria Grazia , Schacht Etienne , Marchal Gilles , Domurado Dominique 
Published: October 2003

ABSTRACT
Long-term antibiotic treatment is required to cure tuberculosis. Targeted antibiotics should improve the efficacy of treatment by concentrating the drugs close to the bacteria. The aim of the present study was to synthesize targeted conjugates. For this purpose, we used mannose as a homing device to direct norfloxacin into macrophages. Dextran was used as the polymer bearing both mannose and norfloxacin. Using different peptide spacer arms to link norfloxacin to dextran, we demonstrated that norfloxacin acts as an antibiotic only when it is released in its native form. Also, targeting by using mannose as a homing device is required to achieve antimycobacterial activity in vivo. Thus, norfloxacin, which is inactive against mycobacteria in its native form in vivo, can be transformed into an active drug by targeting.
pfcrt
Allelic Types with Two Novel Amino Acid Mutations in Chloroquine-Resistant
Plasmodium falciparum
Isolates from the Philippines
Authors: Chen Nanhua , Kyle Dennis E. , Pasay Cielo , Fowler Elizabeth V. , Baker Joanne , Peters Jennifer M. , Cheng Qin 
Published: October 2003

ABSTRACT

Mutations in the
pfcrt
and
pfmdr1
genes have been associated with chloroquine resistance in
Plasmodium falciparum
. Ten and five mutations, respectively, have been identified in these genes from chloroquine-resistant parasites worldwide. Mutation patterns in
pfcrt
revealed that chloroquine resistance evolved independently in southeast Asia, South America, and Papua New Guinea. However, the evolution of chloroquine resistance in the rest of the Pacific region is unclear. In this study, we examined sequence polymorphisms in these genes in isolates from Morong, Philippines, and compared them to known chloroquine resistance sequences. Two novel mutations, A144T and L160Y, were identified outside of the 10 known mutations in
pfcrt
in Morong isolates. These novel mutations were identified only in parasites with K76T and N326D but without the common A220S mutation found in most chloroquine-resistant isolates. This represents a unique chloroquine resistance allelic type (K76T/A144T/L160Y/N326D) not previously found elsewhere in the world. One Morong isolate also had an additional C72S mutation, whereas only one isolate possessed an allelic type typical of chloroquine resistance in Asia. Parasites with the novel
pfcrt
allelic types were resistant to chloroquine in vitro and were unresponsive to verapamil (0.9 μM) chemosensitization, similar to chloroquine-resistant parasites from South America and Papua New Guinea. These results suggest that chloroquine resistance evolved independently in the Philippines and represents a second chloroquine resistance founder event in the South Pacific.