bluuebunny/crossref_metadata_2025 huggingface dataset:
Lithofacies succession of maar crater deposits in the Eifel area (Germany)
Authors: Pirrung M. , Fischer C. , Büchel G. , Gaupp R. , Lutz H. , Neuffer F. ‐O.
Published: December 2004

ABSTRACT Maar craters often contain exceptionally preserved fossils and maar sediments may reflect detailed environmental changes. Volcanosedimentary processes in a Middle Eocene maar crater lake are illustrated by the deposits of Eckfeld Maar in the Tertiary Hocheifel Volcanic Field (Rhenish Massif, Germany). The maar origin of the basin is evident from a circular negative gravity anomaly which indicates a low‐density funnel‐shaped basin filling. From the facies analysis of an Eocene (Eckfeld) and a Pleistocene (Döttingen) maar we develop a lithozone classification for the interpretation of maar sediments: syn‐/post‐eruptive breccias are followed by a fining‐upwards sequence of lacustrine mud with coarse layers and final swamp deposits. From the facies analysis and regional geological data we reconstruct the pre‐ to post‐eruptive history of a maar crater prior to post‐Eocene uplift. These observations can be used for the interpretation of Tertiary and Quaternary maar craters that are ideal fossil and sediment traps.
Molecular characterization and expression of an alfalfa protein with sequence similarity to mammalian ERp72, a glucose‐regulated endoplasmic reticulum protein containing active site sequences of protein disulphide isomerase
Authors: Shorrosh Basil S. , Dixon Richard A.
Published: December 2004

A complementary DMA clone (G1) containing sequence similarity to the mammalian lumenal endoplasmic reticulum protein ERp72 was isolated from an alfalfa (Medicago sativa L.) cDNA library by screening with a cDNA encoding human protein disulphide isomerase (PDI), which contains two thioredoxin‐like active site regions which are highly conserved in ERp72. The poly‐peptide encoded by G1 consists of 364 amino acids, possesses a putative N‐terminal secretory signal sequence and two regions, 113 amino acids apart, identical to the active sites of PDI and ERp72. G1 appears to be encoded by a small gene family in alfalfa, whose transcripts are constitutively expressed in all major organs of the plant. In alfalfa cell suspension cultures, G1 transcripts were markedly induced by treatment with tunicamycin, but not in response to calcium ionophore, heat shock or fungal elicitor. A similar expression pattern was observed for transcripts encoded by B2, a recently cloned alfalfa cDNA with strong sequence similarity to PDI. We discuss potential roles of plant proteins resembling vertebrate PDI and ERp72.
The early nodulin gene SrEnod2 from Sesbania rostrata is inducible by cytokinin
Authors: Dehio Christoph , de Bruijn Frans J.
Published: December 2004

The structure and expression of the early nodulin gene Enod2 from the stem‐nodulated tropical legume Sesbania rostrata (SrEnod2) was examined. Genomic clones carrying the single SrEnod2locus were isolated and the DMA sequence of the gene was determined. The SrEnod2 gene was found to lack introns and to encode a protein consisting primarily of a 55‐fold repeat of short proline‐rich oligopeptides. A putative signal sequence, which may be responsible for targeting of the Enod2 protein to the cell wall, was found to precede this repeat. The temporal expression of the SrEnod2 gene was found to be different in S. rostrata stem versus root nodules induced by Azorhizobium caulinodans ORS571. SrEnod2 gene expression was shown to be induced specifically and rapidly by physiologically significant concentrations of exogenously supplied cytokinins. The SrEnod2gene was also found to be highly expressed in S. rostrata crown gall tumors induced by wild‐type Agrobacterium tumefaciens strains, but not in tumors induced by an A. tumefaciens strain carrying a mutation in the cytokinin biosynthesis gene 4. Implications of these observations with regard to cytokinin‐induced plant gene expression and a possible role for cytokinin as a symbiotic signal are discussed.
Initiation of silencing of maize MuDR/Mu transposable elements
Authors: Rudenko George N. , Ono Akemi , Walbot Virginia
Published: December 2004

Homology‐dependent gene silencing contributes to genomic stability through suppression of transposable elements. Co‐ordinate epigenetic silencing is the main regulatory mechanism controlling dispersed, multicopy MuDR/Mu elements responsible for Mutator activity in maize. Silencing eliminates transposition and proceeds through transcriptional inactivation of MuDR genes and DNA methylation of the terminal inverted repeats (TIRs) in both the regulatory MuDR and non‐autonomous Mu elements. In plants with active MuDR/Mu elements, initiation of silencing coincides with nuclear retention of non‐polyadenylated RNA derived from MuDR and recently described MuDR homologs (hMuDR elements). Nuclear accumulation of MuDR/hMuDR RNA is developmentally progressive, paralleling loss of Mutator activity and is predictive of loss of Mu somatic excision in the progeny. A high ratio of nuclear to cytoplasmic RNA is the earliest molecular marker for MuDR silencing suggesting that the nuclear RNA may trigger transcriptional silencing. We also demonstrate the constitutive presence of small transposon‐specific RNAs of 21–26 nucleotides in all maize lines tested, independent of the Mutator activity. The role of the small RNAs in transposon silencing and translational regulation of transposon‐encoded proteins is discussed.
Identification of photorespiratory glutamate:glyoxylate aminotransferase (GGAT) gene in Arabidopsis
Authors: Igarashi Daisuke , Miwa Tetsuya , Seki Motoaki , Kobayashi Masatomo , Kato Tomohiko , Tabata Satoshi , Shinozaki Kazuo , Ohsumi Chieko
Published: December 2004

In the photorespiratory process, peroxisomal glutamate:glyoxylate aminotransferase (GGAT) catalyzes the reaction of glutamate and glyoxylate to 2‐oxoglutarate and glycine. Although GGAT has been assumed to play important roles for the transamination in photorespiratory carbon cycles, the gene encoding GGAT has not been identified. Here, we report that an alanine:2‐oxoglutarate aminotransferase (AOAT)‐like protein functions as GGAT in peroxisomes. Arabidopsis has four genes encoding AOAT‐like proteins and two of them (namely AOAT1 and AOAT2) contain peroxisomal targeting signal 1 (PTS1). The expression analysis of mRNA encoding AOATs and EST information suggested that AOAT1 was the major protein in green leaves. When AOAT1 fused to green fluorescent protein (GFP) was expressed in BY‐2 cells, it was found to be localized to peroxisomes depending on PTS1. By screening of Arabidopsis T‐DNA insertion lines, an AOAT1 knockout line (aoat1‐1) was isolated. The activity of GGAT and alanine:glyoxylate aminotransferase (AGAT) in the above‐ground tissues of aoat1‐1 was reduced drastically and, AOAT and glutamate:pyruvate aminotransferase (GPAT) activity also decreased. Peroxisomal GGAT was detected in the wild type but not in aoat1‐1. The growth rate was repressed in aoat1‐1 grown under high irradiation or without sugar, though differences were slight in aoat1‐1 grown under low irradiation, high‐CO2 (0.3%) or high‐sugar (3% sucrose) conditions. These phenotypes resembled those of photorespiration‐deficient mutants. Glutamate levels increased and serine levels decreased in aoat1‐1 grown in normal air conditions. Based on these results, it was concluded that AOAT1 is targeted to peroxisomes, functions as a photorespiratory GGAT, plays a markedly important role for plant growth and the metabolism of amino acids.
Phospholipase C is required for the control of stomatal aperture by ABA
Authors: Hunt Lee , Mills Lewis N. , Pical Christophe , Leckie Calum P. , Aitken Fiona L. , Kopka Joachim , Mueller‐Roeber Bernd , McAinsh Martin R. , Hetherington Alistair M. , Gray Julie E.
Published: December 2004

The calcium‐releasing second messenger inositol 1,4,5‐trisphosphate is involved in the regulation of stomatal aperture by ABA. In other signalling pathways, inositol 1,4,5‐trisphosphate is generated by the action of phospholipase C. We have studied the importance of phospholipase C in guard cell ABA‐signalling pathways. Immunolocalisation of a calcium‐activated phospholipase C confirmed the presence of phospholipase C in tobacco guard cells. Transgenic tobacco plants with considerably reduced levels of phospholipase C in their guard cells were only partially able to regulate their stomatal apertures in response to ABA. These results suggest that phospholipase C is involved in the amplification of the calcium signal responsible for reductions in stomatal aperture in response to ABA. As full ABA‐induced inhibition of stomatal opening was not observed, our results support a role for the action of other calcium‐releasing second messengers in the guard cell ABA‐signalling pathway. It is not known whether these different calcium‐releasing second messengers act in the same or parallel ABA‐signalling pathways.
Stress‐induced somatic embryogenesis in vegetative tissues of Arabidopsis thaliana
Authors: Ikeda‐Iwai Miho , Umehara Mikihisa , Satoh Shinobu , Kamada Hiroshi
Published: December 2004

Somatic embryogenesis is an obvious experimental evidence of totipotency, and is used as a model system for studying the mechanisms of de‐differentiation and re‐differentiation of plant cells. Although Arabidopsis is widely used as a model plant for genetic and molecular biological studies, there is no available tissue culture system for inducing somatic embryogenesis from somatic cells in this plant. We established a new tissue culture system using stress treatment to induce somatic embryogenesis in Arabidopsis. In this system, stress treatment induced formation of somatic embryos from shoot‐apical‐tip and floral‐bud explants. The somatic embryos grew into young plantlets with normal morphology, including cotyledons, hypocotyls, and roots, and some embryo‐specific genes (ABI3 and FUS3) were expressed in these embryos. Several stresses (osmotic, heavy metal ion, and dehydration stress) induced somatic embryogenesis, but the optimum stress treatment differed between different stressors. When we used mannitol to cause osmotic stress, the optimal conditions for somatic embryogenesis were 6–9 h of culture on solid B5 medium containing 0.7 m mannitol, after which the explants were transferred to B5 medium containing 2,4‐dichlorophenoxyacetic acid (2,4‐D, 4.5 µm), but no mannitol. Using this tissue culture system, we induced somatic embryogenesis in three major ecotypes of Arabidopsis thaliana– Ws, Col, and Ler.
Arabidopsis microarrays identify conserved and differentially expressed genes involved in shoot growth and development from distantly related plant species
Authors: Horvath David P. , Schaffer Robert , West Mark , Wisman Ellen
Published: December 2004

Expressed sequence tags (EST)‐based microarrays are powerful tools for gene discovery and signal transduction studies in a small number of well‐characterized species. To explore the usefulness of this technique for poorly characterized species, we have hybridized the 11 522‐element Arabidopsis microarrays with labeled cDNAs from mature leaf and shoot apices from several different species. Expression of 23 to 47% of the genes on the array was detected, demonstrating that a large number of genes from distantly related species can be surveyed on Arabidopsis arrays. Differential expression of genes with known functions was indicative of the physiological state of the tissues tested. Genes involved in cell division, stress responses, and development were conserved and expressed preferentially in growing shoots.
Interaction between two mitogen‐activated protein kinases during tobacco defense signaling
Authors: Liu Yidong , Jin Hailing , Yang Kwang‐Yeol , Kim Cha Young , Baker Barbara , Zhang Shuqun
Published: December 2004

Plant mitogen‐activated protein kinases (MAPKs) represented by tobacco wounding‐induced protein kinase (WIPK) have unique regulation at the level of transcription in response to stresses. By using transcriptional and translational inhibitors, it has been shown previously that WIPK gene expression and de novo protein synthesis are required for the high‐level activity of WIPK in cells treated with elicitins from Phytophthora spp. However, regulation of WIPK expression and the role(s) of WIPK in plant disease resistance are unknown. In this report, we demonstrate that WIPK gene transcription is regulated by phosphorylation and de‐phosphorylation events. Interestingly, salicylic acid‐induced protein kinase (SIPK) was identified as the kinase involved in regulating WIPK gene expression based on both gain‐of‐function and loss‐of‐function analyses. This finding revealed an additional level of interaction between SIPK and WIPK, which share an upstream MAPKK, NtMEK2. Depending on whether WIPK shares its downstream targets with SIPK, it could either function as a positive feed‐forward regulator of SIPK or initiate a new pathway. Consistent with the first scenario, co‐expression of WIPK with the active mutant of NtMEK2 leads to accelerated hypersensitive response (HR)‐like cell death in which SIPK also plays a role. Mutagenesis analysis revealed that the conserved common docking domain in WIPK is required for its function. Together with prior reports that (i) WIPK is activated in NN tobacco infected with tobacco mosaic virus, and (ii) PVX virus‐induced gene silencing of WIPK attenuated N gene‐mediated resistance, we concluded that WIPK plays a positive role in plant disease resistance, possibly through accelerating the pathogen‐induced HR cell death.
The Arabidopsis COG1 gene encodes a Dof domain transcription factor and negatively regulates phytochrome signaling
Authors: Park Don Ha , Lim Pyung Ok , Kim Jeong Sik , Cho Dae Shik , Hong Sung Hyun , Nam Hong Gil
Published: December 2004

Light is a critical environmental factor that influences almost all developmental aspects of plants, including seed germination, seedling morphogenesis, and transition to reproductive growth. Plants have therefore developed an intricate network of mechanisms to perceive and process environmental light information. To further characterize the molecular basis of light‐signaling processes in plants, we screened an activation tagging pool of Arabidopsis for altered photoresponses. A dominant mutation, cog1‐D, attenuated various red (R) and far‐red (FR) light‐dependent photoresponses. The mutation was caused by overexpression of a gene encoding a member of the Dof family of transcription factors. The photoresponses in Arabidopsis were inversely correlated with the expression levels of COG1 mRNA. When the COG1 gene was overexpressed in transgenic plants, the plants exhibited hyposensitive responses to R and FR light in a manner inversely dependent on COG1 mRNA levels. On the other hand, transgenic lines expressing antisense COG1 were hypersensitive to R and FR light. Expression of the COG1 gene is light inducible and requires phytochrome A (phyA) for FR light‐induced expression and phytochrome B (phyB) for R light‐induced expression. Thus, the COG1 gene functions as a negative regulator in both the phyA‐ and phyB‐signaling pathways. We suggest that these phytochromes positively regulate the expression of COG1, a negative regulator, as a mechanism for fine tuning the light‐signaling pathway.
TETRASPORE encodes a kinesin required for male meiotic cytokinesis in Arabidopsis
Authors: Yang C‐Y. , Spielman M. , Coles J. P. , Li Y. , Ghelani S. , Bourdon V. , Brown R. C. , Lemmon B. E. , Scott R. J. , Dickinson H. G.
Published: December 2004

A key step in pollen formation is the segregation of the products of male meiosis into a tetrad of microspores, each of which develops into a pollen grain. Separation of microspores does not occur in tetraspore (tes) mutants of Arabidopsis thaliana, owing to the failure of male meiotic cytokinesis. tes mutants thus generate large ‘tetraspores’ containing all the products of a single meiosis. Here, we report the positional cloning of the TES locus and details of the role played by the TES product in male cytokinesis. The predicted TES protein includes an N‐terminal domain homologous to kinesin motors and a C‐terminus with little similarity to other proteins except for a small number of plant kinesins. These include the Arabidopsis HINKEL protein and NACK1 and two from tobacco (), which are involved in microtubule organization during mitotic cytokinesis. Immunocytochemistry shows that the characteristic radial arrays of microtubules associated with male meiotic cytokinesis fail to form in tes mutants. The TES protein therefore is likely to function as a microtubule‐associated motor, playing a part either in the formation of the radial arrays that establish spore domains following meiosis, or in maintaining their stability.
Repression of gene expression by Arabidopsis HD2 histone deacetylases
Authors: Wu Keqiang , Tian Lining , Zhou Changhe , Brown Daniel , Miki Brian
Published: December 2004

The four HD2 proteins of Arabidopsis thaliana (AtHD2A–D) belong to a unique class of histone deacetylases that is plant specific. Previously, we have demonstrated that one of the members, AtHD2A, can mediate transcriptional repression when targeted to the promoter of a reporter gene. Here, we report that AtHD2B and AtHD2C can also repress gene expression. AtHD2A and AtHD2C differ from AtHD2B and AtHD2D in the composition of their structural domains. Our data show that both structural types play a role in the repression of gene transcription. We demonstrate that AtHD2A can mediate gene repression through interactions with transcription factors in plants. By fusing AtHD2A with the DNA‐binding domain of the plant transcriptional factor Pti4, the expression of a GCC box containing reporter gene was repressed. We also demonstrated repression of a GUS gene with GAL4 enhancers using transgenic plants that expressed a GAL4/AtHD2A fusion gene. Furthermore, the expression of the GAL4/AtHD2A protein using the seed‐specific napin promoter (NAP2) and the constitutive tCUP promoter demonstrated that repression of transgenes could be achieved in a tissue‐specific or unrestricted manner. Targeting of HD2 proteins to specific promoters using transcription factor DNA‐binding domains may therefore provide a new technology for silencing target genes and pathways in plants as well as for assessing the function of unknown transcription factors.
Reactive electrophile species activate defense gene expression in Arabidopsis
Authors: Alméras Emmanuelle , Stolz Stéphanie , Vollenweider Sabine , Reymond Philippe , Mène‐Saffrané Laurent , Farmer Edward E.
Published: December 2004

Compounds containing α,β‐unsaturated carbonyl groups are increasingly implicated as potent regulators of gene expression; some are powerful cytotoxins known to accumulate at the site of lesion formation in host–pathogen interactions. We used a robust measurement of photosynthetic efficiency to quantify the toxicity of a variety of lipid derivatives in Arabidopsis leaves. Small α,β‐unsaturated carbonyl compounds (e.g. acrolein and methyl vinyl ketone) were highly active and proved to be potent stimulators of expression of the pathogenesis‐related gene HEL (PR4). These small volatile electrophiles were far more active than larger alkenal homologs like 2(E)‐hexenal, and activated HEL expression in a manner independent of salicylate, ethylene, and jasmonate production/perception. Electrophile treatment massively increased the levels of unesterified cyclopentenone jasmonates, which themselves are electrophiles. Patterns of gene expression in response to electrophile treatment and in response to avirulent bacteria were compared, which revealed strikingly similar transcript profiles. The results broaden the range of known biologic effects of reactive electrophile species to include the activation of a pathogenesis‐related gene (HEL) and genes involved in metabolism. Electrophiles can act as mediators of both genetic and biochemical effects on core defense signal transduction.
Signaling activities among the Arabidopsis phyB/D/E‐type phytochromes: a major role for the central region of the apoprotein
Authors: Sharrock Robert A. , Clack Ted , Goosey Lynn
Published: December 2004

The Arabidopsis phyB, phyD, and phyE phytochromes regulate plant developmental and growth responses to continuous red light (R) and to the ratio of R to far‐red (FR) light. The activities of these three photoreceptors in the control of seedling growth have been compared using a transgenic assay based upon induction of R‐hypersensitivity of hypocotyl elongation by overexpression of the apoproteins from the 35S promoter. 35S‐phyB, 35S‐phyD, and 35S‐phyE lines expressing similar levels of the respective phytochromes were isolated. Under pulses of R, phyB is very active in inducing a dwarf hypocotyl phenotype, whereas phyD and phyE are inactive. Under high‐fluence continuous R, phyD shows a gain in activity whereas phyE does not. These results demonstrate significant differences in the inherent regulatory activities of these receptor apoproteins. To localize the sequence determinants of these functional differences, chimeric proteins were constructed by shuffling amino‐terminal, central, and carboxy‐terminal regions of phyB and phyD. Overexpression analysis of the phyB/D chimeras shows that it is the central region of these proteins that is most critical in determining their respective activities.
Reduced cellulose synthesis invokes lignification and defense responses in Arabidopsis thaliana
Authors: Caño‐Delgado Ana , Penfield Steven , Smith Caroline , Catley Merryn , Bevan Michael
Published: December 2004

The cell wall determines the shape of plant cells and is also the primary interface for pathogen interactions. The structure of the cell wall can be modified in response to developmental and environmental cues, for example to strengthen the wall and to create barriers to pathogen ingress. The ectopic lignin 1‐1 and 1‐2 (eli1‐1 and eli1‐2) mutations lead to an aberrant deposition of lignin, a complex phenylpropanoid polymer. We show that the eli1 mutants occur in the cellulose synthase gene CESA3 in Arabidopsis thaliana and cause reduced cellulose synthesis, providing further evidence for the function of multiple CESA subunits in cellulose synthesis. We show that reduced levels of cellulose synthesis, caused by mutations in cellulose synthase genes and in genes affecting cell expansion, activate lignin synthesis and defense responses through jasmonate and ethylene and other signaling pathways. These observations suggest that mechanisms monitoring cell wall integrity can activate lignification and defense responses.
Ethylene‐mediated enhancement of apical hook formation in etiolated Arabidopsis thaliana seedlings is gibberellin dependent
Authors: Vriezen Wim H. , Achard Patrick , Harberd Nicholas P. , Van Der Straeten Dominique
Published: December 2004

Dark‐grown Arabidopsis seedlings develop an apical hook by differential elongation and division of hypocotyl cells. This allows the curved hypocotyl to gently drag the apex, which is protected by the cotyledons, upwards through the soil. Several plant hormones are known to be involved in hook development, including ethylene, which causes exaggeration of the hook. We show that gibberellins (GAs) are also involved in this process. Inhibition of GA biosynthesis with paclobutrazol (PAC) prevented hook formation in wild‐type (WT) seedlings and in constitutive ethylene response (ctr)1‐1, a mutant that exhibits a constitutive ethylene response. In addition, a GA‐deficient mutant (ga1‐3) did not form an apical hook in the presence of the ethylene precursor 1‐aminocyclopropane‐1‐carboxylate (ACC). Analysis of transgenic Arabidopsis seedlings expressing a green fluorescent protein (GFP)–repressor of ga1‐3 (RGA) fusion protein suggested that ACC inhibits cell elongation in the apical hook by inhibition of GA signaling. A decreased feedback of GA possibly causes an induction of GA biosynthesis based upon the expression of genes encoding copalyl diphosphate synthase (CPS; GA1) and GA 2‐oxidase (AtGA2ox1). Furthermore, expression of GASA1, a GA‐response gene, suggests that differential cell elongation in the apical hook might be a result of differential GA‐sensitivity.
Xa26, a gene conferring resistance to Xanthomonas oryzae pv. oryzae in rice, encodes an LRR receptor kinase‐like protein
Authors: Sun Xinli , Cao Yinglong , Yang Zhifen , Xu Caiguo , Li Xianghua , Wang Shiping , Zhang Qifa
Published: December 2004

Rice bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), is one of the most serious rice diseases worldwide. A rice gene, Xa26, conferring resistance against Xoo at both seedling and adult stages was isolated by map‐based cloning strategies from the rice cultivar Minghui 63. Xa26 belongs to a multigene family consisting of four members. It encodes a leucine‐rich repeat (LRR) receptor kinase‐like protein and is constitutively expressed. Sequence analysis revealed that IRBB3 and Zhachanglong lines that are resistant to a broad range of Xoo strains, also carry Xa26. However, significant difference in lesion length was observed among these lines after inoculation with a set of Xoo strains. Moreover, transgenic plants carrying Xa26 showed enhanced resistance compared with the donor line of the gene in both seedling and adult stages. These results suggest that the resistance conferred by Xa26 is influenced by the genetic background.
Identification of Pseudomonas syringae type III effectors that can suppress programmed cell death in plants and yeast
Authors: Jamir Yashitola , Guo Ming , Oh Hye‐Sook , Petnicki‐Ocwieja Tanja , Chen Shaorong , Tang Xiaoyang , Dickman Martin B. , Collmer Alan , R. Alfano James
Published: December 2004

The Pseudomonas syringae pv. tomato DC3000 type III secretion system (TTSS) is required for bacterial pathogenicity on plants and elicitation of the hypersensitive response (HR), a programmed cell death (PCD) that occurs on resistant plants. Cosmid pHIR11 enables non‐pathogens to elicit an HR dependent upon the TTSS and the effector HopPsyA. We used pHIR11 to determine that effectors HopPtoE, avirulence AvrPphEPto, AvrPpiB1Pto, AvrPtoB, and HopPtoF could suppress a HopPsyA‐dependent HR on tobacco and Arabidopsis. Mixed inoculum and Agrobacterium‐mediated transient expression experiments confirmed that suppressor action occurred within plant cells. These suppressors, with the exception of AvrPpiB1Pto, inhibited the expression of the tobacco pathogenesis‐related (PR) gene PR1a. DC3000 suppressor mutants elicited an enhanced HR consistent with these mutants lacking an HR suppressor. Additionally, HopPtoG was identified as a suppressor on the basis of an enhanced HR produced by a hopPtoG mutant. Remarkably, these proteins functioned to inhibit the ability of the pro‐apoptotic protein, Bax to induce PCD in plants and yeast, indicating that these effectors function as anti‐PCD proteins in a trans‐kingdom manner. The high proportion of effectors that suppress PCD suggests that suppressing plant immunity is one of the primary roles for DC3000 effectors and a central requirement for P. syringae pathogenesis.
Quick detection of Leishmania in peripheral blood by flow cytometry. Is prestorage leucodepletion necessary for leishmaniasis prevention in endemic areas?
Authors: Kyriakou D. S. , Alexandrakis M. G. , Passam F. H. , Kourelis T. V. , Foundouli P. , Matalliotakis E. , Maniatis A. N.
Published: December 2004

summary. Leishmaniasis is a serious health problem in various endemic areas. There are reports that the parasite can be transmitted via blood transfusions. We studied the clinical utility of flow cytometry for the screening of blood donors in an endemic area in Greece.

Samples from 2000 blood donors from the area of Lasithi, Crete, Greece were examined by flow cytometry after labelling with a polyclonal antileishmania antibody conjugated with fluorescein‐isothiocyanate derived from infected canines in the area. The same blood samples were simultaneously examined for serum antileishmania antibodies, May–Grünwald staining of peripheral blood smears and polymerase chain reaction (PCR) in buffy coat to the minicircle of kinetoplastic DNA. Direct sequencing of the PCR‐amplified area helped discriminate leishmania species.

Flow cytometry detected 33 cases with parasites in the peripheral blood leucocytes (1·65%), which were confirmed by PCR. One PCR‐positive case was negative by flow cytometry. After prestorage leucodepletion, no sample was positive by PCR. Antileishmania antibodies were positive in 304 (15%) cases.

Flow cytometry was found to be a sensitive and rapid method of detecting leishmania in peripheral blood samples. Leucodepletion effectively reduces the detection of the parasite, thus minimizing the potential risk of leishmania transmission through blood transfusions in endemic areas.
Renal disease in lymphatic filariasis: evidence for tubular and glomerular disorders at various stages of the infection
Authors: Langhammer J. , Birk H. ‐W. , Zahner H.
Published: December 2004

Brugia malayi‐infected patients, endemic normals with high levels of specific antibodies and European controls were investigated for kidney disorders by noninvasive techniques. Groups of patients with filarial infections included asymptomatic, microfilaraemic cases (group 1), patients with filarial fever (group 2) and with obstructive filariasis (group 3). Several patients underwent a treatment course with diethylcarbamazine (DEC) when blood and urine samples were collected. Urine samples were investigated for proteinuria and analysed by SDS‐PAGE to discriminate between proteinurias caused by tubular and glomerular disorders. In addition, urine levels of α‐1 microglobulin, of the brush border antigen gp400 and of N‐acetyl‐β‐glucosaminidase (NAG) activity were determined as indicators of tubular disorders, the albumin content of the urines served as indicator of glomerular alterations. IgG rheuma factors were also determined in the serum as possible reasons for glomerulonephritis. Neither in the endemic normals nor in the European controls there was evidence for kidney disorders. Infected patients had significantly increased proteinuria compared to controls. There were no significant differences between the 3 groups of infected persons, although the mean protein levels were highest in cases with chronic disease and lowest in asymptomatic patients. Quantitative urine analyses and results of accompanying tests suggest predominantly tubular but generally relatively weak disorders in asymptomatic infections; abundant involvement of the kidney which involves both compartments of the organ in the course of filarial fever; and partly severe and probably chronically progredient kidney alterations, which predominantly affect the glomerula in symptomatic cases. IgG rheuma factors do not seem to play a role in filarial infection associated renal disease. DEC‐treatment indeed did not significantly alter degree and chatacter of the proteinuria, but relatively high albumin levels in the urine of treated persons yet suggest increased glomerular disorders in these cases. In conclusion, renal disease appears to be a common event in Brugia filariasis; involving both the tubular and glomerular compartment of the organ its pathogenesis is obviously complex and not only immune complex‐mediated.
Receptors for carbohydrate ligands including heparin on the cell surface of Leishmania and other trypanosomatids
Authors: Kock N. P. , Gabius H. ‐J. , Schmitz J. , Schottelius J.
Published: December 2004

By employing neoglycoproteins (NGP) and glycosaminoglycans, the detection of endogenous glycoligand‐binding sites has become possible. Monitoring specific binding of 11 of these sugar receptor‐specific tools, 13 trypanosomatids of monogenetic genera Blastocrithidia, Crithidia, Herpetomonas, and Leptomonas and digenetic genera Endotrypanum, Leishmania, and Sauroleishmania were analysed by agglutination and fluorescence assays. NGP showed agglutination reactions only with the digenetic but not with the monogenetic species. Sensitive flow cytofluorimetric investigations revealed that the apparently different reactivity to NGP is due to a pronounced quantitative difference in expression of binding sites between mono‐ and digenetic flagellates. Moreover, flow cytofluorimetry was used to demonstrate the occurrence of receptor sites for heparin on the cell surfaces of all trypanosomatids. An indication for a correlation of the binding capacity for the NGP N‐acetyl‐β‐D‐glucosamine and heparin to differences in the pathogenicity of parasites was observed for Leishmania donovani as well as Leishmania enriettii. Infective populations of these species contained a significantly higher number of cells which had bound N‐acetyl‐β‐D‐glucosamine and heparin than noninfective (long‐term in vitro‐cultured) populations. The results of the present report additionally support the hypothesis that lectin‐carbohydrate interactions with neutral sugar moieties and heparin or heparin‐like molecules participate in the interactions between trypanosomatids and host (cells), and that the detected binding sites for carbohydrates and heparin may thus be referred to as potential virulence factors.
Retrospective follow‐up of maternal deaths and their associated risk factors in a rural district of Tanzania
Authors: MacLeod Jana , Rhode Richard
Published: December 2004

Summary

objective  To determine the maternal mortality rate in a rural district of Tanzania and to measure the incidence of causes of maternal mortality, the presence of risk factors and the relationship with social and demographic factors.

method  From January to December 1993 a retrospective recording of maternal deaths was completed using verbal autopsy and networking.

results  A total of 76 deaths were found which is equivalent to a maternal mortality ratio of 961 per 100,000 live births for this 12‐month period of time. The leading causes of death were postpartum haemorrhage with retained placenta, anaemia, postpartum haemorrhage without retained placenta, AIDS complex and obstructed labour (in descending order of frequency). Maternal deaths were seen irrespective of group factors such as access to a main road, presence of antenatal risk factors and contact with health care personnel or a nearby facility before death. Mortality was also present both in home and hospital deliveries (excluding hospital referrals). Antenatal care had been received by 97.2% of the mothers who died after the second trimester. The referral rate even in the presence of a known antenatal risk factor was 34.6%. Patient compliance to the referral was only 44.4%. Mothers and their families followed strong cultural beliefs even when they were detrimental to the mother's health. Maternal deaths were proportionately higher among women >40 who were also gravid 5, but there was no significant increase in deaths in women < 19 years of age.

conclusion Effective antenatal care, appropriate emergency treatment of complications, access to transportation and competent referral level care with adequate equipment encompass the most effective answers to reduction of maternal deaths at a district level.
Hospital costs of high‐burden diseases: malaria and pulmonary tuberculosis in a high HIV prevalence context in Zimbabwe
Authors: Hongoro Charles , McPake Barbara
Published: December 2004

This paper explores the measurement of hospital costs and efficiency in a context where data is scarce, incomplete or of poor quality. It argues that there is scope for using tracers to examine and compare hospital cost structures and relative efficiency in such contexts. Two high‐burden diseases, malaria and pulmonary tuberculosis, are used as tracers to calculate the average costs of inpatient care at selected tertiary hospitals. This study shows that it is feasible to prospectively collect cost data for specific diseases and explore in detail both patient cost distribution and susceptible areas for efficiency improvement. The present study found that the critical source of efficiency variation in public hospitals in Zimbabwe lies in the way hospital beds are used.
Overview of injection practices in two governorates in Egypt
Authors: Talaat Maha , El‐Oun Said , Kandeel Amr , Abu‐Rabei Wafa , Bodenschatz Caroline , Lohiniva Anna‐Lena , Hallaj Zoheir , Mahoney Frank J.
Published: December 2004

objective To describe the extent and characteristics of injection use and injection providers in Egypt, given that unsafe injections are associated with blood‐borne pathogen transmission.

methods Household surveys of a population‐based sample of residents in the Nile Delta and in Upper Egypt; focus group discussions and in‐depth interviews with community target groups, formal and informal medical providers.

results Of 4197 persons interviewed, 26.2% reported receiving an injection in the past 3 months. Of these, 77% reported it was for therapeutic indications. The age‐sex specific prevalence of injections was highest among children 0–2 years of age and among older adults. Women were more likely to report having an injection than men, particularly at the age above 20 years. Overall, respondents reported receiving on average 4.2 injections per year, indicating that up to 281 million injections are provided per year in Egypt. Injection administrators were public and private sector physicians, pharmacists, barbers, doctor assistants, housekeepers, relatives and friends. Injection prescribers were mostly private and public sector physicians. Of the 1101 respondents who received an injection in the past 3 months, 92 (8.4%) reported that the provider did not use a syringe taken from a closed sealed packet.

conclusion The frequency of therapeutic injection use is high in Egypt and may contribute to blood‐borne pathogen transmission. The Ministry of Health and Population (MOHP) is developing interventions targeted towards promotion of injection safety and reduction of injection overuse on community basis as part of a comprehensive strategy to prevent blood‐borne pathogen transmission in Egypt.
Evidence‐based treatment guidelines for sexually transmitted infections developed with and for female sex workers
Authors: Behets Frieda M. T. F. , Rasolofomanana Justin Ranjalahy , Van Damme Kathleen , Vaovola Georgine , Andriamiadana Jocelyne , Ranaivo Adeline , McClamroch Kristi , Dallabetta Gina , van Dam Johannes , Rasamilalao Désiré , Rasamindra Andry ,   the Mad‐STI Working Group
Published: December 2004

background  Sex work is frequently one of the few options women in low‐income countries have to generate income for themselves and their families. Treating and preventing sexually transmitted infections (STIs) among sex workers (SWs) is critical to protect the health of the women and their communities; it is also a cost‐effective way to slow the spread of HIV. Outside occasional research settings however, SWs in low‐income countries rarely have access to effective STI diagnosis.

objectives  To develop adequate, affordable, and acceptable STI control strategies for SWs.

methods  In collaboration with SWs we evaluated STIs and associated demographic, behavioural, and clinical characteristics in SWs living in two cities in Madagascar. Two months post‐treatment and counselling, incident STIs and associated factors were determined. Evidence‐based STI management guidelines were developed with SW representatives.

results  At baseline, two of 986 SWs were HIV(+); 77.5% of the SWs in Antananarivo and 73.5% in Tamatave had at least one curable STI. Two months post‐treatment, 64.9% of 458 SWs in Antananarivo and 57.4% of 481 women in Tamatave had at least one STI. The selected guidelines include speculum exams; syphilis treatment based on serologic screening; presumptive treatment for gonorrhoea, chlamydia, and trichomoniasis during initial visits, and individual risk‐based treatment during 3‐monthly follow‐up visits. SWs were enthusiastic, productive partners.

conclusions  A major HIV epidemic can still be averted in Madagascar but effective STI control is needed nationwide. SWs and health professionals valued the participatory research and decision‐making process. Similar approaches should be pursued in other resource‐poor settings where sex work and STIs are common and appropriate STI diagnostics lacking.
Clinical presentation of subacute sclerosing panencephalitis in Papua New Guinea
Authors: Mgone Charles S. , Mgone Joyce M. , Takasu Toshiaki , Miki Kenji , Kawanishi Ryuta , Asuo Peter G. , Kono Jacinta , Komase Katsuhiro , Alpers Michael P.
Published: December 2004

Eighty‐three children presented at Goroka Base Hospital in the Eastern Highlands Province (EHP) of Papua New Guinea over a period of 3 years and 9 months between February 1997 and November 2000 were confirmed to have subacute sclerosing panencephalitis (SSPE). Confirmation of the diagnosis was based on the demonstration of high titres of measles antibodies in the cerebrospinal fluid and/or serum in association with clinical features supportive of SSPE, including characteristic electroencephalographic changes and amplification of measles virus genome by reverse transcriptase polymerase chain reaction in some cases. The mean cerebrospinal fluid and serum enzyme immunoassay antibody levels among the SSPE patients were 38 250 and 860 580, respectively. The mean age of onset of SSPE was 7.9 ± 2.6 years and ranged between 2 and 14 years. The overall male to female ratio was 1.2:1 and 1.4:1 for EHP.
Ecological and molecular studies on emerging schistosomiasis mansoni in Dhofar Governorate, Sultanate of Oman
Authors: Moné Hélène , Mouahid Gabriel , Shaban Mahmoud A. , Al Jabri Ali A. , Boissier Jérôme , Ruppel Andreas , Idris Mohamed A.
Published: December 2004

The recent detection of some cases of autochtonous schistosomiasis mansoni in Dhofar, Oman, prompted a search for the transmission sites. The five field surveys we conducted from November 2000 to February 2002 provided ecological data on schistosomiasis in Dhofar. Twenty‐eight water bodies situated within 8–160 km from Salalah, the largest city of Dhofar and at altitudes of up to 900 m, were surveyed for freshwater snails. Biomphalaria arabica was found in 15 of them. Three sites (Tibraq, Siginitti and Arazat) had Schistosoma infected snails, the first snails shedding cercariae of this parasite ever collected in Oman. The parasite from Dhofar was analysed by Random Amplified Polymorphic DNA comparisons using 11 primers and 167 polymorphic fragments and had 87–88% similarity with Schistosoma mansoni from Guadeloupe, but only 37–38% similarity with S. rodhaini from Burundi. Thus, it is a strain of S. mansoni. During the November 2000 survey, the prosobranch snail Melanoides tuberculata was associated with B. arabica in 10 of the 13 B. arabica sites. Cercariae from other species of Digenea emerged from five of the B. arabica sites, including the three named above. This paper presents the first finding of S. mansoni in the Dhofar Governorate and represents an initial study of the biology of S. mansoni transmission. This parasite and its cycle need further biological and molecular characterization, and the clarification of its epidemiological status in Dhofar Governorate is an urgent task.
Prospective evaluation and comparison of the direct agglutination test and an rK39‐antigen‐based dipstick test for the diagnosis of suspected kala‐azar in Nepal
Authors: Chappuis F. , Rijal S. , Singh R. , Acharya P. , Karki B. M. S. , Das M. L. , Bovier P. A. , Desjeux P. , Le Ray D. , Koirala S. , Loutan L.
Published: December 2004

The diagnosis of visceral leishmaniasis (kala‐azar) remains difficult in rural endemic areas and practical and reliable tests are badly needed. Two serological tests, the Direct Agglutination Test (DAT) and an rK39‐antigen‐based dipstick test, were compared to parasitological diagnosis in a group of 184 patients presenting at a tertiary care centre in south‐eastern Nepal with a history of fever ≥14 days and splenomegaly; 139 patients had a parasitologically proven kala‐azar and 45 patients had a negative parasitological work‐up. The rK39 dipstick showed a sensitivity of 97% and a specificity of 71%. The DAT was up to 99% sensitive with a low cut‐off titre (1:400) but its specificity did not exceed 82% even with a high cut‐off titre (1:51 200). Both tests could be used for screening suspect patients in endemic areas. However, their use as confirmatory tests should be restricted to situations where the proportion of kala‐azar among clinical suspect patients is high. The rK39 dipstick is cheaper and easier to use than the DAT and could be used widely provided that both its performance and production remain stable.
Malaria in Mauritania: the first cases of malaria endemic to Nouakchott
Authors: Cortes H. , Morillas‐Márquez F. , Valero A.
Published: December 2004

The current situation of endemic malaria in Mauritania is not clear since, in most health centres, suspected malaria cases are not confirmed by parasitological analysis and diagnosis is based on clinical symptoms alone. To obtain reliable data about malaria in this country, thin and thick blood smears were taken from patients with symptoms compatible with the illness, who attended two hospitals: Polyclinic of Nouakchott, which serves one‐third of the country's population, where a malaria infection rate of 18.5% (77 of 446) was recorded; Plasmodium falciparum caused 61.85% of these, P. vivax 35.5% (28/77). In Kaedi Regional Hospital, provincial capital of the endemic Gorgol region, a prevalence of 25.49% (106 of 416) was recorded, with P. falciparum as the sole pathogenic species. Of the 77 cases of malaria diagnosed in Nouakchott, nine (seven of P. falciparum and two of P. vivax) were considered as endemic to the city. These cases were all children under 8 years of age except for one adult who had never left the capital, and this is the first time that cases endemic to this city have been detected.
Malaria morbidity, treatment‐seeking behaviour, and mortality in a cohort of young children in rural Burkina Faso
Authors: Müller Olaf , Traoré Corneille , Becher Heiko , Kouyaté Bocar
Published: December 2004

Objective To describe the pattern of fever‐associated morbidity, treatment‐seeking behaviour for fever episodes, and cause‐specific mortality in young children of a malaria‐holoendemic area in rural Burkina Faso.

Methods In a longitudinal community‐based intervention study, 709 representative children aged 6–31 months were followed daily over 6 months (including the main malaria transmission period) through village‐based field staff.

results Of 1848 disease episodes, 1640 (89%) were fever episodes, and of those, 894 (55%) were attributed to malaria (fever + ≥5000 parasites/μl). Eighty‐five percent of fever episodes were treated, mainly with chloroquine and paracetamol, 69% of treatments took place in households, 16% in local health centres, 13% in villages, and 1% in hospitals. Treatment‐seeking in a health centre or hospital was associated with accessibility and disease severity. Cerebral malaria and malnutrition‐associated diarrhoea were the most frequently diagnosed causes of death. While most children with a post‐mortem diagnosis of diarrhoea had not received any treatment, children who died of malaria had often received insufficient treatment. In particular, there was a lack of an appropriate second‐line treatment at formal health services after chloroquine treatment had failed to resolve symptoms.

conclusions These findings call for more effective prevention and treatment of malaria, malnutrition and diarrhoea in rural African communities, as well as for better supervision of existing malaria treatment guidelines in formal health services.