bluuebunny/crossref_metadata_2025_split huggingface dataset:
The ethanolic fermentation pathway supports respiration and lipid biosynthesis in tobacco pollen
Authors: Mellema Stefan , Eichenberger Waldemar , Rawyler André , Suter Marianne , Tadege Million , Kuhlemeier Cris 
Published: March 2003

SummaryRapid pollen tube growth requires a high rate of sugar metabolism to meet energetic and biosynthetic demands. Previous work on pollen sugar metabolism showed that tobacco pollen carry out efficient ethanolic fermentation concomitantly with a high rate of respiration (Bucher et al., 1995). Here we show that the products of fermentation, acetaldehyde and ethanol, are further metabolised in a pathway that bypasses mitochondrial PDH. The enzymes involved in this pathway are pyruvate decarboxylase, aldehyde dehydrogenase and acetyl‐CoA synthetase. Radiolabelling experiments show that during tobacco pollen tube growth label of 14C‐ethanol is incorporated into CO2 as well as into lipids and other higher molecular weight compounds. A role for the glyoxylate cycle appears unlikely since activity of malate synthase, a key enzyme of the glyoxylate cycle, could not be detected.
A WD40‐repeat containing protein, similar to a fungal co‐repressor, is required for transcriptional gene silencing in Chlamydomonas
Authors: Zhang Chaomei , Wu‐Scharf Dancia , Jeong Byeong‐ryool , Cerutti Heriberto 
Published: March 2003

SummaryIn higher plants, mammals, and filamentous fungi, transcriptional gene silencing is frequently associated with DNA methylation. However, recent evidence suggests that certain transgenes can be inactivated by a methylation independent mechanism. In the unicellular green alga Chlamydomonas reinhardtii, single‐copy transgenes are transcriptionally silenced without discernible cytosine methylation of the introduced DNA. We have isolated a Chlamydomonas gene, Mut11, which is required for the transcriptional repression of single‐copy transgenes. Mut11 appears to have a global role in gene regulation since it also affects transposon mobilization, cellular growth, and sensitivity to DNA damaging agents. In transient expression assays, a fusion protein between the predicted Mut11 gene product (Mut11p) and E. coli β‐glucuronidase localizes predominantly to the nucleus. Mut11p, a polypeptide of 370 amino acids containing seven WD40 repeats, is highly homologous to proteins of unknown function that are widely distributed among eukaryotes. Mut11p also shows similarity to the C‐terminal domain of TUP1, a global transcriptional co‐repressor in fungi. Based on these findings we speculate that, in Chlamydomonas, the silencing of certain single‐copy transgenes and dispersed transposons integrated into euchromatic regions may occur by a mechanism(s) similar to those involving global transcriptional repressors. Our results also support the existence, in methylation‐competent organisms, of a mechanism(s) of transcriptional (trans)gene silencing that is independent of DNA methylation.
Starch granule initiation and growth are altered in barley mutants that lack isoamylase activity
Authors: Burton Rachel A. , Jenner Helen , Carrangis Luke , Fahy Brendan , Fincher Geoffrey B. , Hylton Chris , Laurie David A. , Parker Mary , Waite Darren , Van Wegen Sonja , Verhoeven Tamara , Denyer Kay 
Published: March 2003

SummaryTwo mutant lines of barley, Risø 17 and Notch‐2, were found to accumulate phytoglycogen in the grain. Like the sugary mutants of maize and rice, these phytoglycogen‐accumulating mutants of barley lack isoamylase activity in the developing endosperm. The mutants were shown to be allelic, and to have lesions in the isoamylase gene, isa1 that account for the absence of this enzyme. As well as causing a reduction in endosperm starch content, the mutations have a profound effect on the structure, number and timing of initiation of starch granules. There are no normal A‐type or B‐type granules in the mutants. The mutants have a greater number of starch granules per plastid than the wild‐type and, particularly in Risø 17, this leads to the appearance of compound starch granules. These results suggest that, as well as suppressing phytoglycogen synthesis, isoamylase in the wild‐type endosperm plays a role in determining the number, and hence the form, of starch granules.
Regulation of ADL6 activity by its associated molecular network
Authors: Lam Bernard C.‐H. , Sage Tammy L. , Bianchi Fabrizio , Blumwald Eduardo 
Published: March 2003

SummaryPlant dynamin‐like proteins consist of a group of high molecular weight GTPase with diverse structural arrangements and cellular localizations. In addition, unlike animal dynamins, there was no evidence for the involvement of any plant dynamin‐like protein in clathrin‐mediated vesicle trafficking. In this study we demonstrate that ADL6 (Arabidopsis dynamin‐like protein 6), due to its domain arrangement, behaves similarly to the animal dynamins. The association of ADL6 with clathrin‐coated vesicles was demonstrated by co‐fractionation and immunocytochemical studies. ADL6 also interacted via its C‐terminus with γ‐adaptin, an adaptor protein of clathrin‐coated vesicles. Our results suggest that ADL6 participates in clathrin‐mediated vesicle trafficking originating from the Golgi. In addition, our studies demonstrate that ADL6 intrinsic GTPase activity is regulated by its association with acidic phospholipids and an SH3 (Src homology 3)‐containing protein.
GLK gene pairs regulate chloroplast development in diverse plant species
Authors: Fitter David W. , Martin David J. , Copley Martin J. , Scotland Robert W. , Langdale Jane A. 
Published: March 2003

SummaryChloroplast biogenesis is a complex process that requires close co‐ordination between two genomes. Many of the proteins that accumulate in the chloroplast are encoded by the nuclear genome, and the developmental transition from proplastid to chloroplast is regulated by nuclear genes. Here we show that a pair of Golden 2‐like (GLK) genes regulates chloroplast development in Arabidopsis. The GLK proteins are members of the GARP superfamily of transcription factors, and phylogenetic analysis demonstrates that the maize, rice and Arabidopsis GLK gene pairs comprise a distinct group within the GARP superfamily. Further phylogenetic analysis suggests that the gene pairs arose through separate duplication events in the monocot and dicot lineages. As in rice, AtGLK1 and AtGLK2 are expressed in partially overlapping domains in photosynthetic tissue. Insertion mutants demonstrate that this expression pattern reflects a degree of functional redundancy as single mutants display normal phenotypes in most photosynthetic tissues. However, double mutants are pale green in all photosynthetic tissues and chloroplasts exhibit a reduction in granal thylakoids. Products of several genes involved in light harvesting also accumulate at reduced levels in double mutant chloroplasts. GLK genes therefore regulate chloroplast development in diverse plant species.
Expression of the Arabidopsis histone H2A‐1 gene correlates with susceptibility to Agrobacterium transformation
Authors: Yi HoChul , Mysore Kirankumar S. , Gelvin Stanton B. 
Published: March 2003

SummaryTransformation of plant cells by Agrobacterium tumefaciens involves both bacterial virulence proteins and host proteins. We have previously shown that the Arabidopsis thaliana gene H2A‐1 (RAT5), which encodes histone H2A‐1, is involved in T‐DNA integration into the plant genome. Mutation of RAT5 results in a severely decreased frequency of transformation, whereas overexpression of RAT5 enhances the transformation frequency (Mysore et al., 2000b). We show here that the expression pattern of RAT5 correlates with plant root cells most susceptible to transformation. As opposed to a cyclin‐GUS fusion gene whose expression is limited to meristematic tissues, the H2A‐1 gene is expressed in many non‐dividing cells. Under normal circumstances, the H2A‐1 gene is expressed in the elongation zone of the root, the region that is most susceptible to Agrobacterium transformation. In addition, when roots are incubated on medium containing phytohormones, a concomitant shift in H2A‐1 expression and transformation susceptibility to the root base is observed. Inoculation of root segments with a transfer‐competent, but not a transformation‐deficient Agrobacterium strain induces H2A‐1 expression. Furthermore, pre‐treatment of Arabidopsis root segments with phytohormones both induces H2A‐1 expression and increases the frequency of Agrobacterium transformation. Our results suggest that the expression of the H2A‐1 gene is both a marker for, and a predictor of, plant cells most susceptible to Agrobacterium transformation.
Controlling gene expression in plants using synthetic zinc finger transcription factors
Authors: Stege Justin T. , Guan Xuen , Ho Thao , Beachy Roger N. , Barbas Carlos F. 
Published: March 2003

SummarySynthetic zinc finger proteins can be fused to transcriptional regulatory domains to create artificial transcription factors that modulate the expression of a specific target gene. Recent studies have demonstrated that synthetic zinc finger domains can be constructed to bind DNA sequences with a high degree of specificity. To devise a general strategy for controlling plant gene expression with artificial transcription factors, a rapid transient assay was developed to test the regulatory activity of synthetic zinc finger transcription factors (effectors) on target plasmids (reporters) in plant cells. Effective activation was demonstrated with zinc finger proteins fused to a derivative of the VP16 activation domain. The mSin3 interaction domain (SID) of the human MAD1 protein provided moderate repression of target reporters. Unlike many naturally occurring transcription factors, these synthetic effectors exhibit a strong dependence on binding site position. Reporter genes that are stably integrated into plant cells responded similarly to transiently transfected reporter plasmids, verifying that this assay accurately reflects the behavior of these transcription factors on an endogenous target within the context of chromosomal DNA. These results provide evidence that synthetic zinc finger proteins can be used to manipulate the expression of endogenous genes in plants.
Pleural tuberculosis in Harare, Zimbabwe: the relationship between human immunodeficiency virus, CD4 lymphocyte count, granuloma formation and disseminated disease
Authors: Heyderman R. S. , Makunike R. , Muza T. , Odwee M. , Kadzirange G. , Manyemba J. , Muchedzi C. , Ndemera B. , Gomo Z. A. R. , Gwanzura L. K. Z. , Mason P. R. 
Published: March 2003

objective

To elucidate the relationship between HIV, CD41 count and pleural TB.method  In a prospective study, 94 patients presenting at two large Harare hospitals with clinically suspected pleural TB were enrolled over a 10‐month period. All underwent standardized evaluation, closed pleural aspiration and biopsy. Patients receiving directly observed anti‐TB therapy were followed‐up.results  Pleural TB was diagnosed in 90 individuals (median age 33 years; range 18‐65; 64 males); the seroprevalence of HIV was 85%. HIV‐positive patients were older than HIV‐negative individuals (median age 33 vs 23 years, P= 0.013) and had a significantly lower median CD41 count (191 vs 1106 × 106/l respectively, P= 0.004). A CD41 count of <200 × 106/l was associated with a length of illness >30 days (65% vs 37%; P= 0.05), a positive pleural fluid smear (37% vs 0%; P= 0.0006) and a positive pleural biopsy Ziehl‐Neelsen stain (35% vs 7%; P= 0.021). However, a relationship between CD41 count and either pleural granuloma formation or radiological evidence of disseminated disease was not observed.conclusion  In sub‐Saharan Africa, TB pleural effusions have become associated with older age, a chronic onset, and an increased mycobacterial load. These data emphasize the complex relationship between pleural TB, HIV infection and a low CD41 count.
Prolonged macrophage activation and persistent anaemia in children with complicated malaria
Authors: Biemba G. , Gordeuk V. R. , Thuma P. E. , Mabeza G. F. , Weiss G. 
Published: March 2003

objective

To determine if prolonged immune activation may be associated with the persistence of anaemia after treatment for severe malaria, we measured serum concentrations of neopterin and interleukin‐4 during one week of antimalarial therapy and determined haemoglobin levels one month later. Neopterin is a clinically valuable marker for monitoring activation of macrophages by gamma‐interferon and thus reflects the TH‐1 immune response. Interleukin‐4 is a major cytokine that tends to be inhibited by TH‐1 activity.method  The study population consisted of 26 Zambian children <6 years of age who presented with cerebral malaria to a rural hospital in 1994 and who were treated with quinine for seven days. Six children (23%) were anaemic (haemoglobin < 11 g/dl) one month after completing antimalarial therapy.results  On admission, concentrations of neopterin were markedly elevated in all patients. During the seven days of anti‐malarial therapy, neopterin levels remained elevated in the 6 children who proved to have persistent anaemia one month after finishing treatment but declined significantly (P = 0.008) in the 20 children who corrected their haemoglobin levels by that time. Conversely, interleukin‐4 levels declined in the children with persistent anaemia (P= 0.043) but not in the other children.conclusion  Persistence of the TH‐1 mediated immune response and associated activation of macrophages may be involved in the pathogenesis of lingering anaemia after treatment of malaria.
Evaluation of the SPf66 vaccine for malaria control when delivered through the EPI scheme in Tanzania
Authors: Acosta C. J. , Galindo C. M. , Schellenberg D. , Aponte J. J. , Kahigwa E. , Urassa H. , Schellenberg J. R. M. Armstrong , Masanja H. , Hayes R. , Kitua A. Y. , Lwilla F. , Mshinda H. , Menendez C. , Tanner M. , Alonso P. L. 
Published: March 2003

Summarybackground Malaria control programmes need to protect young children, who bear the brunt of malaria disease and death in Africa. The development of a vaccine is a priority if improved and sustained malaria control is to be achieved. The best use of a vaccine in Africa will be achieved if it can be delivered through the expanded programme of immunization (EPI). We conducted a trial designed to evaluate the efficacy of SPf66 vaccine for malaria control when delivered through the EPI scheme in Tanzania.methods The study was a two‐arm, double blind, individually randomized placebo controlled trial involving 1207 infants. The primary objective of the trial was to estimate the efficacy of three doses of SPf66 given at 1, 2 and 7 months of age in preventing clinical episodes of malaria. These were documented through a health facility‐based passive case detection system.results Among 1207 randomized children, overall compliance for third dose was 91%. SPf66 was safe, immunogenic and did not interfere with the humoral immune responses to EPI vaccines. There were 294 children among SPf66 recipients and 288 among placebo recipients with at least one malaria episode, yielding a vaccine efficacy estimate of 2% (95% CI: −16, 16;P = 0.84).conclusion This has been the first trial of a malaria vaccine among very young infants. It provides information on the safety of peptide vaccines administered at this early age as well as their capacity to induce immune responses without negatively interacting with EPI vaccines. Given the modest protection previously documented in older age groups and the lack of efficacy in younger infants, this vaccine in its current alum‐based formulation does not appear to have a role in malaria control in sub‐Saharan Africa. The lack of efficacy found in this trial also raises concerns about potential difficulties of inducing protective immune responses against malaria through immunization in infants.
Safety in infants of SPf66, a synthetic malaria vaccine, delivered alongside the EPI
Authors: Schellenberg D. M. , Acosta C. J. , Galindo C. M. , Kahigwa E. , Urassa H. , Masanja H. , Aponte J. J. , Schellenberg J. R. M. Armstrong , Fraser‐Hurt N. , Lwilla F. , Menendez C. , Mshinda H. , Tanner M. , Alonso P. L. 
Published: March 2003

Summary The most likely mechanism to deliver a malaria vaccine in African countries is through the Expanded Program of Immunization (EPI). So far only SPf66, a multistage synthetic peptide, has shown any evidence of protection in Phase III field trials. In Tanzania, SPf66 reduced the risk of clinical malaria by 31% in children aged 1–5 years. In order to progress in the critical path of vaccine development and testing towards the implementation of a new vaccine in malaria control programs, we carried out a randomized double‐blind placebo controlled efficacy trial of SPf66 when given alongside the EPI scheme. Monitoring of safety and reactogenicity during this trial included detailed clinical and laboratory assessments on 98 infants and assessment of adverse effects within 1 h of vaccination for all 1207 children vaccinated. Surveillance systems monitored attendances as outpatients, admissions to hospital and fatal events in the community. No serious adverse effects were detected more frequently amongst SPf66 recipients compared to placebo. This first assessment in very young infants of a synthetic vaccine provides evidence of a good safety profile.
Is there a role for glycosuria testing in sub‐Saharan Africa?
Authors: van der Sande Marianne A. B. , Walraven Gijs E. L. , Bailey Robin , Rowley Jane T. F. , Banya Winston A. S. , Nyan Ousman A. , Faal Hannah , Ceesay Sana M. , Milligan Paul J. M. , McAdam Keith P. W. J. 
Published: March 2003

Summary background With increasing urbanization and westernization, rates of diabetes in sub‐Saharan Africa (sSA) are likely to rise. Early detection and intervention plays an important role in delaying development of complications. In sSA in particular there is need for an affordable, reliable, safe, feasible test to avert human suffering and exhausting already stressed health facilities. methods Data from two large community‐based studies were used to assess the value of glycosuria testing in the detection of diabetes in adults in a sub‐Saharan country. A first study (A) tested participants for glycosuria by dipstick; if positive, fasting capillary glucose was measured. A later study (B) measured glucose concentration in venous blood 2 h after a 75‐g glucose load; if glycaemia was ≥ 10 mmol/l, urine was tested for glycosuria. results The positive predictive value of glycosuria for a diagnosis of diabetes (fasting glucose ≥ 6.7 mmol/l) was 48%. Sensitivity was 64% (57% if a 2‐h‐value ≥ 10 mmol/l was used as gold standard). Sensitivity was higher among overweight and/or hypertensive subjects, among elderly people in the urban area, and among subjects with higher blood glucose levels. Extrapolated specificity was 99.7%, and the likelihood ratio 190. conclusions Glycosuria testing can identify a considerable number of undiagnosed diabetic patients when specially targeted at high‐risk groups (obese, hypertensive, or elderly people). Dipstick glycosuria testing is an appropriate, safe, feasible test for sSA, where the prevalence of diabetes is expected to increase considerably in the near future.
Isolation and partial characterization of dengue virus type 2 and 4 strains from dengue fever and dengue haemorrhagic fever patients from Mindanao, Republic of the Philippines
Authors: ter Meulen J. , Grau M. , Lenz O. , Emmerich P. , Schmitz H. , Oh F. , Jaspert R. , Niedrig M. 
Published: March 2003

Summary objective  Isolation of dengue virus from dengue fever and dengue haemorrhagic fever cases from Mindanao, Republic of the Philippines. methods  12 patients with clinically suspected dengue fever (DF) or dengue haemorrhagic fever (DHF) presenting in four regional hospitals between August and September 1995 on Minadano were enrolled in the study. Dengue virus was isolated by inoculation of Vero/E6 or C6/36 cells with patient serum. IgM antibodies were measured using a commercial test system. Up to 454 bp of the capsid region and 240 bp of the E/NS1 gene junction of different viral isolates were sequenced and phylogenetically analyzed. results  Virus could be isolated from seven patients, five isolates were typed as dengue virus type 2 and two as dengue virus type 4 by immunostaining with monoclonal antibodies or by RT/PCR. Phylogenetic analysis confirmed a close relationship of the dengue virus type 2 isolates with viruses isolated in the Philippines in 1983 and 1988. conclusion  As observed in studies from other parts of South East Asia, dengue virus type 2 was readily isolated from dengue haemorrhagic fever cases. Dengue virus type 2 and 4 circulate in Mindanao, Philippines, with dengue type 2 being responsible for most of our severe DF or DHF cases.
Toxic activities of the plant Jatropha curcas against intermediate snail hosts and larvae of schistosomes
Authors: Rug Melanie , Ruppel Andreas 
Published: March 2003

Summary The aim of studies on plant molluscicides is to complement methods for controlling snails acting as intermediate hosts of schistosomes. We report on the toxic activity of extracts from Jatropha curcas L. (Euphorbiaceae) against snails transmitting Schistosoma mansoni and S. haematobium. We studied different extracts' effects on infectious larvae, cercariae and miracidia of S. mansoni. Compared to aqueous extract, methanol extract showed the highest toxicity against all tested organisms with LC100‐values of 25 p.p.m. for cercariae and the snail Biomphalaria glabrata and 1 p.p.m. for the snails Bulinus truncatus and B. natalensis. Attenuation of cercariae leading to reduced infectivity in mice could be achieved in concentrations below those exerting acute toxicity. In view of our results and the ongoing exploitation of J. curcas for other purposes, this plant could become an affordable and effective component of an integrated approach to schistosomiasis control.
Treatment for clinical malaria is sought promptly during an epidemic in a highland region of Uganda
Authors: Lindblade Kim A. , O'neill Devin B. , Mathanga Don P. , Katungu Justus , Wilson Mark L. 
Published: March 2003

Summary Early diagnosis of malaria followed by appropriate treatment can help reduce related morbidity and mortality as well as interrupt transmission. Previous studies of household responses to malaria have tended to focus on endemic areas where the burden of this disease is greatest. With the apparent increasing frequency of epidemics in African highlands, a better understanding of treatment behaviours in areas of unstable transmission may be important to future public health interventions. This study was undertaken following a serious epidemic of malaria in the highlands of south‐western Uganda. Our objectives were to characterize actions taken by both adults and caretakers of children ≤5 years old during their most recent episode of self‐diagnosed malaria, and to identify factors that were associated with prompt treatment at a health facility. A survey of 300 households selected in a 2‐stage cluster sampling procedure produced 453 adult respondents and 133 caretakers of children ≤5 years old. We found that almost 65% of adults and 62% of children who had experienced an episode of malaria in the last year (most during the epidemic) had sought treatment from a health facility first as opposed to self‐treatment. Most of these people had visited the health facility within 1 day of symptom onset. By the end of their malaria episode, over 87% of adults and 80% of children had visited a health facility at least once. Factors associated with prompt presentation at a health facility included severity of illness, household proximity to a health facility, and knowledge of malaria prevention methods. Our results indicate that there is an important role for the formal health care system in mitigating morbidity and mortality and reducing transmission during malaria epidemics in Uganda.