bluuebunny/crossref_metadata_2025_split huggingface dataset:
NepA is a structural cell wall protein involved in maintenance of spore dormancy in Streptomyces coelicolor
Authors: De Jong Wouter , Manteca Angel , Sanchez Jesus , Bucca Giselda , Smith Colin P. , Dijkhuizen Lubbert , Claessen Dennis , Wösten Han A. B. 
Published: February 2009

SummaryStreptomycetes have a complex morphogenetic programme culminating in the formation of aerial hyphae that develop into chains of spores. After spore dispersal, environmental signals trigger dormant spores to germinate to establish a new colony. We here compared whole genome expression of a wild‐type colony of Streptomyces coelicolor forming aerial hyphae and spores with that of the chp null mutant that forms few aerial structures. This revealed that expression of 244 genes was significantly altered, among which genes known to be involved in development. One of the genes that was no longer expressed in the ΔchpABCDEFGH mutant was nepA, which was previously shown to be expressed in a compartment connecting the substrate mycelium with the sporulating parts of the aerial mycelium. We here show that expression is also detected in developing spore chains, where NepA is secreted to end up as a highly insoluble protein in the cell wall. Germination of spores of a nepA deletion mutant was faster and more synchronous, resulting in colonies with an accelerated morphogenetic programme. Crucially, spores of the ΔnepA mutant also germinated in water, unlike those of the wild‐type strain. Taken together, NepA is the first bacterial structural cell wall protein that is important for maintenance of spore dormancy under unfavourable environmental conditions.
Duration of control of two soilborne pathogens following incorporation of above‐ and below‐ground residues of Brassica juncea into soil
Authors: Motisi N. , Montfort F. , Doré T. , Romillac N. , Lucas P. 
Published: February 2009

The persistence of control of primary infections caused by two soilborne fungal plant pathogens, Rhizoctonia solani and Gaeumannomyces graminis var. tritici, following the incorporation of above‐ground parts (AP), below‐ground parts (BP) or both (AP+BP) of Brassica juncea into soil was examined through an experiment in controlled conditions. Control was quantified by measuring disease incidence in bioassays where inoculum was introduced at different dates after the incorporation of plant residues. All types of residue showed an unexpected long‐term persistence that lasted at least 13 days, while the predominant glucosinolates contained in AP (20·9 µmol sinigrin g−1 dry matter) and BP (2·3 µmol gluconasturtiin g−1 dry matter) were hydrolysed in less than 3 days. Temporal trends in the efficacy of the residues behaved mostly in a quadratic manner, suggesting that the noxious effect of residues may be attributable to the release of isothiocyanates during the first days following incorporation, but that other mechanisms are most likely to contribute to lasting persistence. Across all treatments, AP and AP+BP suppressed R. solani by 54 and 63%, respectively, and G. graminis var. tritici by 40 and 40%, respectively, compared with controls. While BP did not cause any additional detectable effect when combined with AP, they had a significant effect when incorporated alone (approximately 20% suppression of both species), suggesting the existence of a complex interaction between these two types of residue.
POT1‐independent single‐strand telomeric DNA binding activities in Brassicaceae
Authors: Shakirov Eugene V. , McKnight Thomas D. , Shippen Dorothy E. 
Published: February 2009

SummaryTelomeres define the ends of linear eukaryotic chromosomes and are required for genome maintenance and continued cell proliferation. The extreme ends of telomeres terminate in a single‐strand protrusion, termed the G‐overhang, which, in vertebrates and fission yeast, is bound by evolutionarily conserved members of the POT1 (protection of telomeres) protein family. Unlike most other model organisms, the flowering plantArabidopsis thalianaencodes two divergent POT1‐like proteins. Here we show that the single‐strand telomeric DNA binding activity present inA. thaliananuclear extracts is not dependent on POT1a or POT1b proteins. Furthermore, in contrast to POT1 proteins from yeast and vertebrates, recombinant POT1a and POT1b proteins fromA. thaliana, and from two additional Brassicaceae species,Arabidopsis lyrataandBrassica oleracea(cauliflower), fail to bind single‐strand telomeric DNAin vitrounder the conditions tested. Finally, although we detected four single‐strand telomeric DNA binding activities in nuclear extracts fromB. oleracea, partial purification and DNA cross‐linking analysis of these complexes identified proteins that are smaller than the predicted sizes of BoPOT1a or BoPOT1b. Taken together, these data suggest that POT1 proteins are not the major single‐strand telomeric DNA binding activities inA. thalianaand its close relatives, underscoring the remarkable functional divergence of POT1 proteins from plants and other eukaryotes.
The effector protein Avr2 of the xylem‐colonizing fungus Fusarium oxysporum activates the tomato resistance protein I‐2 intracellularly
Authors: Houterman Petra M. , Ma Lisong , Van Ooijen Gerben , De Vroomen Marianne J. , Cornelissen Ben J.C. , Takken Frank L.W. , Rep Martijn 
Published: February 2009

SummaryTo promote host colonization, many plant pathogens secrete effector proteins that either suppress or counteract host defences. However, when these effectors are recognized by the host’s innate immune system, they trigger resistance rather than promoting virulence. Effectors are therefore key molecules in determining disease susceptibility or resistance. We show here that Avr2, secreted by the vascular wilt fungus Fusarium oxysporum f. sp. lycopersici (Fol), shows both activities: it is required for full virulence in a susceptible host and also triggers resistance in tomato plants carrying the resistance gene I‐2. Point mutations in AVR2, causing single amino acid changes, are associated with I‐2‐breakingFol strains. These point mutations prevent recognition by I‐2, both in tomato and when both genes are co‐expressed in leaves of Nicotiana benthamiana. Fol strains carrying the Avr2 variants are equally virulent, showing that virulence and avirulence functions can be uncoupled. Although Avr2 is secreted into the xylem sap when Fol colonizes tomato, the Avr2 protein can be recognized intracellularly by I‐2, implying uptake by host cells.
Interplay between SCARECROW, GA and LIKE HETEROCHROMATIN PROTEIN 1 in ground tissue patterning in the Arabidopsis root
Authors: Cui Hongchang , Benfey Philip N. 
Published: February 2009

SummaryRegulated cell division is critical for the development of multi‐cellular organisms. In the Arabidopsis root, SCARECROW (SCR) is required for the first cell division, but represses the subsequent, longitudinal asymmetric cell divisions that generate the two cell types of the ground tissue – cortex and endodermis. To elucidate the molecular basis of the role of SCR in ground tissue patterning, we screened for SCR‐interacting proteins using the yeast two‐hybrid method. A number of putative SCR‐interacting proteins were identified, among them LIKE HETEROCHROMATIN PROTEIN 1 (LHP1). In lhp1 mutants, a second longitudinal asymmetric cell division occurs in the ground tissue earlier than in wild‐type plants. Similar to the scr mutant, this premature middle cortex phenotype is suppressed by the phytohormone gibberellin (GA). We provide evidence that the N‐terminal domain of SCR is required for the interaction between SCR and LHP1 as well as with other interacting partners, and that this domain is essential for repression of asymmetric cell divisions. Consistent with a role for GA in cortex proliferation, mutants of key GA signaling components produce a middle cortex precociously. Intriguingly, we found that the spindly (spy) mutant has a similar middle cortex phenotype. As SPY homologs in animals physically interact with histone deacetylase, we examined the role of histone deacetylation in middle cortex formation. We show that inhibition of histone deacetylase activity causes premature middle cortex formation in wild‐type roots. Together, these results suggest that epigenetic regulation is probably the common basis for SCR and GA activity in cortex cell proliferation.
Cytosolic activity of SPINDLY implies the existence of a DELLA‐independent gibberellin‐response pathway
Authors: Maymon Inbar , Greenboim‐Wainberg Yaarit , Sagiv Sivan , Kieber Joseph J. , Moshelion Menachem , Olszewski Neil , Weiss David 
Published: February 2009

SummarySpecific plant developmental processes are modulated by cross‐talk between gibberellin (GA)‐ and cytokinin‐response pathways. Coordination of the two pathways involves the O‐linked N‐acetylglucosamine transferase SPINDLY (SPY) that suppresses GA signaling and promotes cytokinin responses in Arabidopsis. Although SPY is a nucleocytoplasmic protein, its site of action and targets are unknown. Several studies have suggested that SPY acts in the nucleus, where it modifies nuclear components such as the DELLA proteins to regulate signaling networks. Using chimeric GFP–SPY fused to a nuclear‐export signal or to a glucocorticoid receptor, we show that cytosolic SPY promotes cytokinin responses and suppresses GA signaling. In contrast, nuclear‐localized GFP–SPY failed to complement the spy mutation. To examine whether modulation of cytokinin activity by GA and spy is mediated by the nuclear DELLA proteins, cytokinin responses were studied in double and quadruple della mutants lacking the activities of REPRESSOR OF GA1‐3 (RGA) and GA‐INSENSITIVE (GAI) or RGA, GAI, RGA Like1 (RGL1) and RGL2. Unlike spy, the della mutants were cytokinin‐sensitive. Moreover, when GA was applied to a cytokinin‐treated quadruple della mutant it was able to suppress various cytokinin responses. These results suggest that cytosolic SPY and GA regulate cytokinin responses via a DELLA‐independent pathway(s).
PLASTOCHRON3/GOLIATH encodes a glutamate carboxypeptidase required for proper development in rice
Authors: Kawakatsu Taiji , Taramino Graziana , Itoh Jun‐Ichi , Allen Justin , Sato Yutaka , Hong Soon‐Kwan , Yule Ryan , Nagasawa Nobuhiro , Kojima Mikiko , Kusaba Makoto , Sakakibara Hitoshi , Sakai Hajime , Nagato Yasuo 
Published: February 2009

SummaryMost aerial parts of the plant body are products of the continuous activity of the shoot apical meristem (SAM). Leaves are the major component of the aerial plant body, and their temporal and spatial distribution mainly determines shoot architecture. Here we report the identification of the rice gene PLASTOCHRON3 (PLA3)/GOLIATH (GO) that regulates various developmental processes including the rate of leaf initiation (the plastochron). PLA3/GO encodes a glutamate carboxypeptidase, which is thought to catabolize small acidic peptides and produce small signaling molecules. pla3 exhibits similar phenotypes to pla1 and pla2– a shortened plastochron, precocious leaf maturation and rachis branch‐to‐shoot conversion in the reproductive phase. However, in contrast to pla1 and pla2, pla3 showed pleiotropic phenotypes including enlarged embryo, seed vivipary, defects in SAM maintenance and aberrant leaf morphology. Consistent with these pleiotropic phenotypes, PLA3 is expressed in the whole plant body, and is involved in plant hormone homeostasis. Double mutant analysis revealed that PLA1, PLA2 and PLA3 are regulated independently but function redundantly. Our results suggest that PLA3 modulates various signaling pathways associated with a number of developmental processes.
Molecular and reverse genetic characterization of NUCLEOSOME ASSEMBLY PROTEIN1 (NAP1) genes unravels their function in transcription and nucleotide excision repair in Arabidopsis thaliana
Authors: Liu Ziqiang , Zhu Yan , Gao Juan , Yu Fang , Dong Aiwu , Shen Wen‐Hui 
Published: February 2009

SummaryCompared with the well‐studied biochemical function of NUCLEOSOME ASSEMBLY PROTEIN1 (NAP1) as a histone chaperone in nucleosome assembly/disassembly, the physiological roles of NAP1 remain largely uncharacterized. Here, we define the NAP1 gene family members in Arabidopsis, examine their molecular properties, and use reverse genetics to characterize their biological roles. We show that the four AtNAP1‐group proteins can form homodimers and heterodimers, can bind histone H2A, and are localized abundantly in the cytoplasm and weakly in the nucleus at steady state. AtNAP1;4 differs from the others by showing inhibitor‐sensitive nucleocytoplasmic shuttling and tissue‐specific expression, restricted to root segments and pollen grains. The other three AtNAP1 genes are ubiquitously expressed in plants and the AtNAP1;3 protein is detected as the major isoform in seedlings. We show that disruption of the AtNAP1‐group genes does not affect normal plant growth under our laboratory conditions. Interestingly, two allelic triple mutants, Atnap1;1‐1 Atnap1;2‐1 Atnap1;3‐1 and Atnap1;1‐1 Atnap1;2‐1 Atnap1;3‐2, exhibit perturbed genome transcription, and show hypersensitivity to DNA damage caused by UV‐C irradiation. We show that AtNAP1;3 binds chromatin, with enrichment at some genes involved in the nucleotide excision repair (NER) pathway, and that the expression of these genes is downregulated in the triple mutants. Taken together, our results highlight conserved and isoform‐specific properties of AtNAP1 proteins, and unravel their function in the NER pathway of DNA damage repair.
The plant adherin AtSCC2 is required for embryogenesis and sister‐chromatid cohesion during meiosis in Arabidopsis
Authors: Sebastian Jose , Ravi Maruthachalam , Andreuzza Sebastien , Panoli Aneesh P. , Marimuthu Mohan P. A. , Siddiqi Imran 
Published: February 2009

SummaryAdherin plays an important role in loading the cohesin complex onto chromosomes, and is essential for the establishment of sister‐chromatid cohesion. We have identified and analyzed the Arabidopsis adherin homolog AtSCC2. Interestingly, the sequence analysis of AtSCC2 and of other putative plant adherin homologs revealed the presence of a PHD finger, which is not found in their fungal and animal counterparts. AtSCC2 is identical to EMB2773, and mutants show early embryo lethality and formation of giant endosperm nuclei. A role for AtSCC2 in sister‐chromatid cohesion was established by using conditional RNAi and examining meiotic chromosome organization. AtSCC2‐RNAi lines showed sterility, arising from the following defects in meiotic chromosome organization: failure of homologous pairing, loss of sister‐chromatid cohesion, mixed segregation of chromosomes and chromosome fragmentation. The mutant phenotype, which included defects in chromosome organization and cohesion in prophase I, is distinct from that of the Arabidopsis cohesin mutant Atrec8, which retains centromere cohesion up to anaphase I. Immunostaining experiments revealed the aberrant distribution of the cohesin subunit AtSCC3 on chromosomes, and defects in chromosomal axis formation, in the meiocytes of AtSCC2‐RNAi lines. These results demonstrate a role for AtSCC2 in sister‐chromatid cohesion and centromere organization, and show that the machinery responsible for the establishment of cohesion is conserved in plants.
PCR and direct agglutination as Leishmania infection markers among healthy Nepalese subjects living in areas endemic for Kala‐Azar
Authors: Bhattarai Narayan Raj , Van der Auwera Gert , Khanal Basudha , De Doncker Simonne , Rijal Suman , Das Murari Lal , Uranw Surendra , Ostyn Bart , Praet Nicolas , Speybroeck Niko , Picado Albert , Davies Clive , Boelaert Marleen , Dujardin Jean‐Claude 
Published: February 2009

SummaryObjective  To compare a PCR assay and direct agglutination test (DAT) for the detection of potential markers of Leishmania infection in 231 healthy subjects living in a kala‐azar endemic focus of Nepal.Methods  The sample was composed of 184 (80%) persons without any known history of KA and not living in the same house as known kala‐azar cases (HNK), 24 (10%) Healthy Household Contacts (HHC) and 23 (10%) past kala‐azar cases which had been successfully treated (HPK).Results  PCR and DAT positivity scores were, respectively: HNK, 17.6% and 5.6%; HHC, 12.5% and 20.8%; HPK, 26.1% and 95.7%. The ratio PCR‐positives/DAT‐positives was significantly higher in HNK (ratio = 3.1) than in HHC (ratio = 0.6, P = 0.036) and in HPK (ratio = 0.2, P = 0.012). The ratio PCR‐positives/DAT‐positives did not significantly differ between HHC (ratio = 0.6) and HPK (ratio = 0.2, P = 0.473). The positive agreement index between PCR and DAT in HNK was 5%; in HHC, 0%; in HPK, 43%.Conclusions  Our study highlights the specific character of PCR and DAT for the exploration of Leishmania asymptomatic infections. PCR is probably more informative for very recent infections among HNK, while DAT provides more information among HHC and HPK, a feature likely related to the power of serology to track less recent infections.
Control of pyrethroid‐resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin
Authors: N’Guessan Raphael , Boko Pelagie , Odjo Abiba , Knols Bart , Akogbeto Martin , Rowland Mark 
Published: February 2009

SummaryObjective  To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance.Method  Eight‐week trial conducted in experimental huts.Results  Indoor residual spraying killed 82.9% of An. gambiae overall (mean mortality: 79.5%) compared to 53.5% overall (mean mortality: 61.7%) in the hut containing the lower dosed ITN. Analysis of data on a fortnightly basis showed high levels of mosquito mortality and blood‐feeding inhibition during the first few weeks after treatment. Control of C. quinquefasciatus by the IRS and ITN interventions showed a similar trend to that of An. gambiae and though the average level of mortality was lower it was still much higher than with pyrethroid treatments against this population. Chlorfenapyr’s reputation for being rather slow acting was evident particularly at lower dosages. The treatments showed no evidence of excito‐repellent activity in this trial.Conclusion  Chlorfenapyr has the potential to control pyrethroid resistant populations of A. gambiae. There is a need to develop long‐lasting formulations of chlorfenapyr to prolong its residual life on nets and sprayed surfaces. On nets it could be combined with a contact irritant pyrethroid to give improved protection against mosquito biting while killing pyrethroid‐resistant mosquitoes that come into contact with the net.
Rapid malaria diagnostic tests vs. clinical management of malaria in rural Burkina Faso: safety and effect on clinical decisions. A randomized trial
Authors: Bisoffi Zeno , Sirima Bienvenu Sodiomon , Angheben Andrea , Lodesani Claudia , Gobbi Federico , Tinto Halidou , Van den Ende Jef 
Published: February 2009

SummaryObjectives  To assess if the clinical outcome of patients treated after performing a Rapid Diagnostic Test for malaria (RDT) is at least equivalent to that of controls (treated presumptively without test) and to determine the impact of the introduction of a malaria RDT on clinical decisions.Methods  Randomized, multi‐centre, open clinical trial in two arms in 2006 at the end of the dry and of the rainy season in 10 peripheral health centres in Burkina Faso: one arm with use of RDT before treatment decision, one arm managed clinically. Primary endpoint: persistence of fever at day 4. Secondary endpoints: frequency of malaria treatment and of antibiotic treatment.Results  A total of 852 febrile patients were recruited in the dry season and 1317 febrile patients in the rainy season, and randomized either to be submitted to RDT (P_RTD) or to be managed presumptively (P_CLIN). In both seasons, no significant difference was found between the two randomized groups in the frequency of antimalarial treatment, nor of antibiotic prescription. In the dry season, 80.8% and 79.8% of patients with a negative RDT were nevertheless diagnosed and treated for malaria, and so were 85.0% and 82.6% negative patients in the rainy season. In the rainy season only, both diagnosis and treatment of other conditions were significantly less frequent in RDT positive vs. negative patients (48.3%vs. 61.4% and 46.2%vs. 59.9%, P = 0.00 and 0.00, respectively).Conclusion  Our study was inconclusive on RDT safety (clinical outcome in the two randomized groups), because of an exceedingly and unexpectedly low compliance with the negative test result. Further research is needed on best strategies to promote adherence and on the safety of a test based strategy compared with the current, presumptive treatment strategy.
Successful oral tolerance induction in severe peanut allergy
Authors: Clark A. T. , Islam S. , King Y. , Deighton J. , Anagnostou K. , Ewan P. W. 
Published: February 2009

Background:  Peanut allergy is common, potentially severe and rarely resolves causing impaired quality of life. No disease‐modifying treatment exists and there is therefore a need to develop a therapeutic intervention.Aims of the study:  The aim of this study was to investigate whether peanut oral immunotherapy (OIT) can induce clinical tolerance to peanut protein.Methods:  Four peanut‐allergic children underwent OIT. Preintervention oral challenges were performed to confirm clinical allergy and define the amount of protein required to cause a reaction (dose thresholds). OIT was then administered as daily doses of peanut flour increasing from 5 to 800 mg of protein with 2‐weekly dose increases. After 6 further weeks of treatment, the oral challenge was repeated to define change in dose threshold and subjects continued daily treatment.Results:  Preintervention challenges confirmed peanut allergy and revealed dose thresholds of 5–50 mg (1/40–1/4 of a whole peanut); one subject had anaphylaxis during challenge and required adrenaline injection. All subjects tolerated immunotherapy updosing to 800 mg protein and i.m. adrenaline was not required. Each subject tolerated at least 10 whole peanuts (approximately 2.38 g protein) in postintervention challenges, an increase in dose threshold of at least 48‐, 49‐, 55‐ and 478‐fold for the four subjects.Conclusions:  We demonstrated a substantial increase in dose threshold after OIT in all subjects, including the subject with proven anaphylaxis. OIT was well tolerated and conferred protection against at least 10 peanuts, more than is likely to be encountered during accidental ingestion.
Serum interleukin‐17 levels are related to clinical severity in allergic rhinitis
Authors: Ciprandi G. , De Amici M. , Murdaca G. , Fenoglio D. , Ricciardolo F. , Marseglia G. , Tosca M. 
Published: February 2009

Background:  T helper (Th)‐17 cells are a subset of T helper lymphocytes that exert regulatory activities. Recently, it has been reported that serum interleukin (IL)‐17 levels are high in the most severe cases of birch allergy studied outside the pollen season.Objective:  The aim of this study was to investigate a possible relationship between serum IL‐17 levels and clinical parameters in patients with allergic rhinitis studied during the pollen season.Methods:  In all, 56 patients with persistent pollen‐induced allergic rhinitis were evaluated during the pollen season. Serum IL‐17 levels were evaluated by enzyme‐linked immunosorbent assay. Symptoms were assessed by visual analogue scale, drug use was monitored and peripheral eosinophils were counted.Results:  Serum IL‐17 levels were significantly related to clinical symptoms, drug use and peripheral eosinophil counts (P = 0.0001 for all).Conclusion:  This study provides evidence that serum IL‐17 level assessment might be considered to classify allergy severity.