bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synergistic interaction of the two paralogous Arabidopsis genes LRX1 and LRX2 in cell wall formation during root hair development
Authors: Baumberger N. , Steiner M. , Ryser U. , Keller B. , Ringli C. 
Published: July 2003

SummaryLRR‐extensins (LRX) form a family of structural cell wall proteins containing a receptor‐like domain. The functional analysis of Arabidopsis LRX1 has shown that it is involved in cell morphogenesis of root hairs. In this work, we have studied LRX2, a paralog of LRX1. LRX2 expression is mainly found in roots and is responsive to factors promoting or repressing root hair formation. The function of LRX1 and LRX2 was tested by the expression of a truncated LRX2 and different LRX1/LRX2 chimaeric proteins. Using complementation of the lrx1 phenotype as the parameter for protein function, our experiments indicate that LRX1 and LRX2 are functionally similar but show differences in their activity. Genetic analysis revealed that single lrx2 mutants do not show any defect in root hair morphogenesis, but synergistically interact with the lrx1 mutation. lrx1/lrx2 double mutants have a significantly enhanced lrx1 phenotype, resulting in frequent rupture of the root hairs soon after their initiation. Analysis of the root hair cell wall ultrastructure by transmission electron microscopy (TEM) revealed the formation of osmophilic aggregates within the wall, as well as local disintegration of the wall structure in the double mutant, but not in wild‐type plants. Our results indicate that LRX1 and LRX2 have overlapping functions in root hair formation, and that they likely regulate cell morphogenesis by promoting proper development of the cell wall.
The capacity of transgenic tobacco to send a systemic RNA silencing signal depends on the nature of the inducing transgene locus
Authors: Mallory Allison C. , Mlotshwa Sizolwenkosi , Bowman Lewis H. , Vance Vicki B. 
Published: July 2003

SummaryRNA silencing is a conserved eukaryotic pathway in which double‐stranded RNA (dsRNA) triggers destruction of homologous target RNA via production of short‐interfering RNA (siRNA). In plants, at least some cases of RNA silencing can spread systemically. The signal responsible for systemic spread is expected to include an RNA component to account for the sequence specificity of the process, and transient silencing assays have shown that the capacity for systemic silencing correlates with the accumulation of a particular class of small RNA. Here, we report the results of grafting experiments to study transmission of silencing from stably transformed tobacco lines in the presence or absence of helper component‐proteinase (HC‐Pro), a viral suppressor of silencing. The studied lines carry either a tail‐to‐tail inverted repeat, the T4‐IR transgene locus, or one of two different amplicon transgene loci encoding replication‐competent viral RNA. We find that the T4‐IR locus, like many sense‐transgene‐silenced loci, can send a systemic silencing signal, and this ability is not detectably altered by HC‐Pro. Paradoxically, neither amplicon locus effectively triggers systemic silencing except when suppressed for silencing by HC‐Pro. In contrast to results from transient assays, these grafting experiments reveal no consistent correlation between capacity for systemic silencing and accumulation of any particular class of small RNA. In addition, although all transgenic lines used to transmit systemic silencing signals were methylated at specific sites within the transgene locus, silencing in grafted scions occurred without detectable methylation at those sites in the target locus of the scion.
Molecular characterization of the Arabidopsis 9‐cis epoxycarotenoid dioxygenase gene family
Authors: Tan Bao‐Cai , Joseph Leina M. , Deng Wen‐Tao , Liu Lijuan , Li Qin‐Bao , Cline Kenneth , McCarty Donald R. 
Published: July 2003

SummaryA key regulated step in abscisic acid (ABA) biosynthesis in plants is catalyzed by 9‐cis epoxycarotenoid dioxygenase (NCED), which cleaves 9‐cis xanthophylls to xanthoxin, a precursor of ABA. In Arabidopsis, ABA biosynthesis is controlled by a small family of NCED genes. Nine carotenoid cleavage dioxygenase (CCD) genes have been identified in the complete genome sequence. Of these, five AtNCEDs (2, 3, 5, 6, and 9) have been cloned and studied for expression and subcellular localization. Although all five AtNCEDs are targeted to plastids, they differ in binding activity of the thylakoid membrane. AtNCED2, AtNCED3, and AtNCED6 are found in both stroma and thylakoid membrane‐bound compartments. AtNCED5 is exclusively bound to thylakoids, whereas AtNCED9 remains soluble in stroma. A quantitative real‐time PCR analysis and histochemical staining of promoter::GUS activity in transgenic Arabidopsis revealed a complex pattern of localized NCED expression in well‐watered plants during development. AtNCED2 and AtNCED3 account for the NCED activity in roots, with localized expression in root tips, pericycle, and cortex cells at the base of lateral roots. Localized AtNCED2 and AtNCED3 expression in pericycle cells is an early marker of lateral initiation sites. AtNCED5, AtNCED6, AtNCED3, and AtNCED2 are expressed in flowers with very high AtNCED6::GUS activity occurring in pollen. AtNCED5::GUS, and to lesser degrees, AtNCED2::GUS and AtNCED3::GUS are expressed in developing anthers. AtNCED5, AtNCED6, AtNCED9, and AtNCED3 contribute to expression in developing seeds with high levels of AtNCED6 present at an early stage. GUS analysis indicates that AtNCED3 expression is confined to the base of the seed, whereas AtNCED5 and AtNCED6 are expressed throughout the seed. Consistent with the studies conducted by Iuchi and his colleagues in 2001, AtNCED3 is the major stress‐induced NCED in leaves. Our results indicate that developmental control of ABA synthesis involves localized patterns of AtNCED gene expression. In addition, differential membrane‐binding capacity of AtNCEDs is a potential means of post‐translational regulation of NCED activity.
An Arabidopsis protein closely related to Synechocystis cryptochrome is targeted to organelles
Authors: Kleine Tatjana , Lockhart Peter , Batschauer Alfred 
Published: July 2003

SummaryCryptochromes (CRYs) are blue/UV‐A photoreceptors related to the DNA repair enzyme DNA photolyase. They have been found in plants, animals and most recently in the cyanobacterium Synechocystis. Closely related to the Synechocystis cryptochrome is the Arabidopsis gene At5g24850. Here, we show that the encoded protein of At5g24850 binds flavin adenine dinucleotide (FAD). It has no photolyase activity, and is likely to function as a photoreceptor. We have named it At‐cry3 to distinguish it from the other Arbabidopsis cryptochrome homologues At‐cry1 and At‐cry2. At‐cry3 carries an N‐terminal sequence, which mediates import into chloroplasts and mitochondria. Furthermore, we show that At‐cry3 binds DNA. DNA binding was also demonstrated for the Synechocystis cryptochrome, indicating that both photoreceptors could have similar modes of action. Based on the finding of a new cryptochrome class in bacteria and plants, it has been suggested that cryptochromes evolved before the divergence of eukaryotes and prokaryotes. However, our phylogenetic analyses are also consistent with an alternative explanation that the presence of cryptochromes in the plant nuclear genome is the result of dual horizontal gene transfer. That is, CRY1 and CRY2 genes may originate from an endosymbiotic ancestor of modern‐day α‐proteobacteria, while the CRY3 gene may originate from an endosymbiotic ancestor of modern‐day cyanobacteria.
Urban malaria: primary caregivers’ knowledge, attitudes, practices and predictors of malaria incidence in a cohort of Ugandan children
Authors: Njama Denise , Dorsey Grant , Guwatudde David , Kigonya Kate , Greenhouse Bryan , Musisi Stephen , Kamya Moses R. 
Published: July 2003

SummaryObjectives To assess malaria‐related knowledge, attitude and practices (KAP) among primary caregivers, to identify associations between primary caregivers’ characteristics and positive KAP towards malaria, and to identify independent predictors of childhood malaria incidence in an urban setting.Methods Children aged 6 months to 5 years living in Kampala, Uganda were enrolled as part of a longitudinal study on antimalarial therapy. Primary caregivers of 307 children were interviewed and information was collected on demographics, malaria‐related KAP, environmental and household factors. Malaria incidence was measured prospectively using passive surveillance.Results A total of 90% of respondents reported mosquitoes and/or malaria as the cause of fever. Caregivers reported that if their child had fever, 63% would go to a clinic or hospital as their first action and 97% as their first or second action. Only 38% knew that chloroquine was the recommended first‐line treatment for malaria and 29% knew the correct dose. Preventive measures for malaria were reported in 45% of households but only 25% reported using bednets. Higher levels of education for the caregiver were associated with positive malaria‐related KAP. Malaria incidence varied widely. The following were independent predictors of malaria incidence: (1) Children aged 24–41 months at enrolment had a higher incidence of malaria. (2) Reported bednet or chemoprophylaxis use reduced the incidence of malaria. (3) A child's place of residence was associated with incidence. (4) Children from households using open water sources had a higher incidence than those using closed sources.Conclusion Primary caregivers were knowledgeable about malaria and used modern health care facilities but knew less about the proper administration of antimalarials and had limited use of preventive measures. Malaria incidence was associated with child's age at enrolment, geography, source of water and the use of preventive measures.
Clinical presentation and diagnostic sensitivity of laboratory tests for Strongyloides stercoralis in travellers compared with immigrants in a non‐endemic country
Authors: Sudarshi Sonali , Stümpfle Richard , Armstrong Margaret , Ellman Thomas , Parton Simon , Krishnan Prabha , Chiodini Peter L. , Whitty Christopher J. M. 
Published: July 2003

SummaryObjectives To assess whether the clinical and laboratory methods for diagnosing Strongyloides stercoralis infection in non‐endemic countries is different between those who are chronically exposed and those who travel.Methods Analysis of laboratory and clinical data from 204 patients having S. stercoralis infection at the Hospital for Tropical Diseases, London.Results Sixty‐four travellers and 128 immigrants from endemic countries had laboratory‐proven strongyloides. In those with microscopically proven disease, serology was 73% sensitive in travellers and 98% sensitive in immigrants (P < 0.001). There was no difference in the eosinophil count between the two groups with 19% having a normal count. Patterns of symptoms varied between the groups, and around one‐third were asymptomatic in both groups. Serology was of limited use in follow‐up.Conclusions Eosinophil count and stool microscopy are insufficiently sensitive to be used alone for screening strongyloides. The sensitivity of serology is good in immigrants with chronic infection, but lower in travellers.
A fatal case of human babesiosis in Portugal: molecular and phylogenetic analysis
Authors: Centeno‐Lima S. , Do Rosário V. , Parreira R. , Maia A. J. , Freudenthal A. M. , Nijhof A. M. , Jongejan F. 
Published: July 2003

SummaryWe report the first case of human babesiosis in Portugal. A 66‐year‐old splenectomized man was admitted to a Lisbon hospital after 1 week of fever, abdominal pain, anorexia and nausea. A high parasitaemia (30%) of Babesia parasites was found in Giemsa‐stained blood smears and, despite treatment, the patient died several weeks later of renal failure. Ethylenediaminetetraacetic acid blood samples were processed for polymerase chain reaction (PCR) and reverse line blot hybridization to confirm and characterize the Babesia infection. The amplified PCR product was cloned and subsequently sequenced. Molecular analysis showed that the infection was caused by Babesia divergens and that other blood parasites were not involved. Phylogenetic analysis showed that the 18 S ribosomal RNA gene sequence was similar to three other European isolates of B. divergens. In view of the high risk for splenectomized individuals, strict measures should be taken to avoid tick bites.
Low awareness of intestinal schistosomiasis in northern Senegal after 7 years of health education as part of intense control and research activities
Authors: Sow Seydou , de Vlas Sake J. , Mbaye Amadou , Polman Katja , Gryseels Bruno 
Published: July 2003

SummaryWe evaluated the awareness of and knowledge about intestinal schistosomiasis in a highly infected rural community of northern Senegal where a variety of health information and education activities had taken place for 7 years as a component of different research and control programmes. As the infection had been introduced only recently, an initial ‘zero’ knowledge can be assumed. Most of the health education activities had been performed with adapted messages through local health and community workers. By a questionnaire, 566 individuals were asked simple questions on symptoms, mode of transmission, the sources of information and health‐seeking behaviour. About 86% of the respondents stated that they knew what schistosomiasis was, and 92% that in case of illness they would seek treatment at the health centre. However, only half of the people accurately quoted symptoms associated with intestinal schistosomiasis: diarrhoea, abdominal pain and bloody stools. The majority of respondents realized that the disease was somehow linked with water and (lack of) hygiene, but only 44% of respondents reported water contact as the source of infection. Ultimately, only 30% of the respondents gave adequate answers about both symptoms and mode of transmission. We conclude that even intense and long‐lasting education efforts for a specific and straightforward problem as schistosomiasis are not enough to have profound impact on the knowledge of rural traditional communities.
Performance of the acetic acid test when used in field conditions as a screening test for cervical cancer
Authors: Claeys P. , De Vuyst H. , Gonzalez C. , Garcia A. , Bello R. E. , Temmerman M. 
Published: July 2003

SummaryObjective To assess if visual inspection with acetic acid (VIA) is a useful alternative screening test for cervical cancer, when used in a resource‐poor setting with an existing cytology‐based screening programme.Methods Women living in Rivas district (Nicaragua), who attended the programme, were concurrently screened with VIA and Papanicolau (PAP) smear. Screening was performed by health providers who had received training in VIA and a refresher course in cytology. Women testing positive for either of the results were referred for colposcopy and biopsy when indicated. The performance of VIA was compared with PAP smear, calculating the relative true and false positive rate (RELTPR and RELFPR) and for a high threshold on biopsy (cervical intraepithelial neoplasia grade 2 or a higher grade). We determined the trade‐off between both tests by calculating the ratio of extra false positives detected through extra true positives (EFP:ETP ratio).Results A total of 1076 patients were screened. Nearly 33% had a positive screening test. On biopsy, 7.6% had a low‐grade intraepithelial lesion, 4.5% a high‐grade intraepithelial lesion (HSIL) and 0.5% invasive cancer. The RELTPR (VIA to PAP) was 1.96, the RELFPR 5.02 and the EFP:ETP ratio 8.04. VIA detected twice as much HSIL and invasive cancers as the PAP smear. Yet, for every extra diagnosis, eight extra false positives had to be examined at the referral level.Conclusions The VIA spectacularly increases the number of HSIL and invasive cancers detected. The high FPR is a concern for the organization of the referral level. There is a need to establish uniform criteria on test positivity and to further improve the performance in field conditions.
Which health services reduce maternal mortality? Evidence from ratings of maternal health services
Authors: Bulatao Rodolfo A. , Ross John A. 
Published: July 2003

SummaryWe report cross‐national regressions for maternal mortality in 49 developing countries, using indices of the adequacy of maternal health services derived from ratings by at least 10 experts per country. As in previous such regressions, a socioeconomic factor – in this case per capita income – has a significant effect, but having a trained attendant at delivery does not. Instead, the ratings index for access to services has a consistent, significant effect regardless of which estimates of maternal mortality ratios are predicted. Further analysis suggests that access to treatment for pregnancy complications and to services that help avoid pregnancy and birth are most closely related to lower mortality. Service ratings are interdependent, however, so that focusing only on individual services may not be productive.
Monitoring mosquito net coverage for malaria control in Africa: possession vs. use by children under 5 years
Authors: Korenromp Eline L. , Miller John , Cibulskis Richard E. , Kabir Cham M. , Alnwick David , Dye Christopher 
Published: July 2003

SummaryObjectives To investigate the strengths and weaknesses of the indicators ‘proportion of households possessing mosquito net(s)’ and ‘proportion of children under 5 years of age who slept under a net the preceding night’ for monitoring malaria control.Methods Review of data from household surveys including demographic and health surveys in sub‐Saharan African countries.Results Net possession ranged among 14 surveyed regions from 0.1% to 28.5% for insecticide‐treated nets (ITNs) and among 69 regions from 3.6% to 79.7% for any net. Reported use during the preceding night by children under 5 years of age was between 0% and 16% for ITNs and between 0.7% and 74.5% for any net. On average, in households owning ITN(s), 55% of children slept under it (R2 = 0.97, P < 0.001). For any net, use was −4.2% + 0.875 × possession (R2 = 0.89, P < 0.001); the use of nets, however, also varied somewhat among the surveyed countries (P = 0.003). In‐depth surveys suggested that use was lower than possession because: (i) nets were scarce (mean 1.8 per possessing household); (ii) nets were not always used for children and (iii) use was lower during hot, dry months than during cool rainy months, and many surveys had been conducted in the dry season.Conclusions Not all mosquito nets owned by African households are being used for young children. Household education on the consistent use of nets for this vulnerable group is called for in malaria control programmes. Regular, district‐level rapid assessments of household possession of nets should complement ongoing in‐depth surveys. Data on ‘use during the preceding night’ must be interpreted taking the survey season into account.
Evaluation of the seroprevalence of rubella in the region of Dakar (Senegal)
Authors: Dromigny J. A. , Nabeth P. , Perrier Gros Claude J. D. 
Published: July 2003

SummaryData on the seroepidemiology of rubella in tropical African countries are still scarce. To determine the seroprevalence in Senegal, we conducted a 6 year retrospective survey among women of child bearing age in the urban region of Dakar, Senegal. The global seroprevalence determined with a commercial enzyme immunoassay among 3471 serological results was 90.1%. The distribution of this prevalence appeared stable with no significant difference between the years of study, age groups, and the socio‐economic level of the districts of residence of the patients. Compared to seroepidemiological surveys performed in other western African countries, our data suggest an important and stable circulation of the virus in the region of Dakar. The lack of data on rubella and congenital rubella syndrome (CRS) in Senegal should encourage medical authorities to establish a national rubella surveillance network in order to develop a strategy to survey and control CRS in the country.
The effect of soil type and climate on hookworm (Necator americanus) distribution in KwaZulu‐Natal, South Africa
Authors: Mabaso M. L. H. , Appleton C. C. , Hughes J. C. , Gouws E. 
Published: July 2003

SummaryWe investigated environmental factors influencing the distribution of hookworm infection in KwaZulu‐Natal, South Africa. Prevalence data were sourced from previous studies and additional surveys carried out to supplement the database. When geo‐referenced the data revealed that higher prevalences are limited to areas below 150 m above sea level, and low prevalences to areas above this altitude. Using univariate analysis we investigated the differences in environmental factors in the two areas. The relationship between hookworm prevalence, altitude and climate‐derived variables was assessed using Pearson correlation coefficient, and that of soil type using the t‐test. Multivariate analysis was used to determine environmental factors that combine best to provide favourable conditions for hookworm distribution. The results revealed that areas ≤150 m above sea level, i.e. the coastal plain, supported high prevalences (x̄ = 45, n = 51), and were characterized by sandy soils with a clay content of less than 15%, warm temperatures and relatively high rainfall. Areas >150 m above sea level, i.e. inland, supported low mean hookworm prevalences (x̄ = 6, n = 21), and were characterized by soils with a clay content of more than 45%, variable temperatures and moderate rainfall. Hookworm prevalence also decreased southwards as temperatures became slightly cooler, rainfall remained more‐or‐less constant and the coastal plain narrowed. In the multivariate model prevalence was most significantly correlated with the mean daily minimum temperature for January followed by the mean number of rainy days for January. This indicates the importance of summer conditions in the transmission of hookworm infection in KwaZulu‐Natal and suggests that transmission may be seasonal.
Pentoxifylline adjunct improves prognosis of human cerebral malaria in adults
Authors: Das B. K. , Mishra S. , Padhi P. K. , Manish R. , Tripathy R. , Sahoo P. K. , Ravindran B. 
Published: July 2003

SummaryFifty‐two adult patients with cerebral malaria were randomly categorized into two groups to receive either quinine dihydrochloride (Qn) alone or a combination of Qn and pentoxifylline (Px). Thirty‐two of them received intravenous (i.v.) Qn (group I), and 20 patients (group II) received i.v. Qn along with parenteral Px support (10 mg/kg/day) for the initial 3 days. There was significant improvement in coma resolution time in group II (21.6 ± 13.9 h) in comparison with group I (63.5 ± 19.7 h) (P < 0.001), and mortality was 25% of patients in group I against 10% patients receiving Px adjunct (P > 0.05). Three days post‐therapy, serum tumour necrosis factor‐α (TNF‐α) levels decreased significantly in patients on Px support (day 0 TNF = 415.62 ± 477.80 pg/ml; day 3 TNF = 47.92 ± 27.9 pg/ml; P = 0.0029). There was no significant change in TNF levels in those on quinine alone (day 0 TNF = 477.08 ± 933.90 pg/ml; day 3 TNF = 589 ± 602.3 pg/ml; P > 0.05). There were no serious side‐effects necessitating withdrawal of patients receiving Px therapy.