bluuebunny/crossref_metadata_2025 huggingface dataset:
Timing of Late Neoproterozoic glaciation on Baltica constrained by detrital zircon geochronology in the Hedmark Group, south‐east Norway
Authors: Bingen B. , Griffin W. L. , Torsvik T. H. , Saeed A.
Published: June 2005

The Moelv Tillite is the Late Neoproterozoic Varanger glacial deposit recorded in the Hedmark Group, SE Norway. Paired U–Pb and Lu–Hf data collected on detrital zircons in the Rendalen Formation underlying the Moelv Tillite have identified an uncommon 677 ± 15 to 620 ± 14 Ma population, that constrain the deposition of the Moelv Tillite to be younger than 620 ± 14 Ma. The youngest detrital zircons may be derived from granite magmatism related to the 616 ± 3 Ma Egersund dolerite magmatism, situated in the western part of the Sveconorwegian orogen. The Moelv Tillite, which is not overlain by a cap carbonate, possibly correlates with the c. 580 Ma Squantum‐Gaskiers glacial deposits of Avalonia. Available palaeomagnetic data for the Late Neoproterozoic suggest that Baltica was located at intermediate to high latitude between 620 and 555 Ma.
A clinopyroxene–basalt geothermobarometry perspective of Columbia Plateau (NW‐USA) Miocene magmatism
Authors: Caprarelli Graziella , Reidel Stephen P.
Published: June 2005

The origin of NW‐USA Columbia River Basalt Group Miocene magmatism and its relation to tectonism has been widely debated and is still open to study. We investigated the pre‐eruptive evolution of the magmas, to constrain pressures and temperatures of the ascending magmas, and plumbing conditions. We determined major element concentrations of 17–6 Ma tholeiites, and applied clinopyroxene – liquid geothermobarometry to calculate pre‐eruptive pressures and temperatures. These ranged from 0 to 0.66 GPa and 1120 to 1222 °C, respectively, defining two age‐related parallel trends in a P–T diagram. This indicates a consistent crustal evolution of the magmas, and records at least two distinct initial temperatures. Using clinopyroxene interdiffusion coefficients we estimated magma ascent speeds ≥ 0.6 km yr−1. Possible geological explanations for the calculated parameters are: lower‐crust magma chamber processes; magmatism and tectonism feed‐back consistent with an extensional environment.
Hydrous partial melting within the lower oceanic crust
Authors: Koepke Juergen , Feig Sandrin T. , Snow Jonathan
Published: June 2005

We studied more than 60 oceanic gabbros from the recent oceanic crust and from ophiolites (East Pacific Rise, Mid‐Atlantic Ridge, Southwest Indian Ridge, Oman ophiolite) by scanning electron microscopy and found in nearly all samples microstructures suggesting that hydrous partial melting reactions proceeded. The characteristic paragenesis consists of orthopyroxene and pargasite rimming olivine and clinopyroxene primocrysts in intimate contact with neoblastic plagioclase strongly enriched in anorthite. This is in agreement with recent water‐saturated melting experiments on a variety of natural gabbros between 900 and 1000 °C. The observed microtextures in the natural gabbros imply the propagation of water‐rich fluids on grain boundaries in a ductile regime causing hydrous partial melting. Thus, this type of hydrothermal activity proceeds within the deep oceanic crust at very high temperatures (900–1000 °C) without a crack system, a prerequisite in current models for enabling hydrothermal circulation.
New results of 40Ar/39Ar dating constrain the timing of transition from fissure‐type to central volcanism at Mount Etna (Italy)
Authors: De Beni Emanuela , Wijbrans Jan R. , Branca Stefano , Coltelli Mauro , Groppelli Gianluca
Published: June 2005

Recent geological studies performed at Etna allow reassessing the stratigraphic frame of the volcano where distinct evolutionary phases are defined. This stratigraphic reconstruction was chronologically constrained on the basis of a limited number of U–Th and K–Ar age determinations whose uncertainty margins are sometimes too wide. For this reason, we successfully adopted at Etna the 40Ar/39Ar technique that allowed obtaining more precise age determinations. The incremental heating technique also gives information on sample homogeneity, and potential problems of trapped argon. Five samples were collected from stratigraphically well‐controlled volcanic units in order to chronologically define the transition between the fissure‐type volcanism of the Timpe phase to the central volcanism of the Valle del Bove Centers. Isotopic ages with an uncertainty margin of 2–4% have been obtained emphasizing that this transition occurred (130–126 ka) without significant temporal hiatus.
Developmental and light effects on the accumulation of FtsH protease in Arabidopsis chloroplasts – implications for thylakoid formation and photosystem II maintenance
Authors: Zaltsman Adi , Feder Ari , Adam Zach
Published: May 2005

The chloroplast ATP‐dependent metalloprotease FtsH is involved in the degradation of unassembled proteins, the repair of photosystem II (PSII) from photoinhibition, and, apparently, the formation of thylakoids. In Arabidopsis, it is encoded by a family of 12 genes. However, the products of only four of them, FtsH1, 2, 5 and 8, have been found in chloroplasts to date. Mutations in two of these, FtsH2 and 5, demonstrate a visible phenotype of variegated leaves, with the phenotype of the FtsH2 mutant being more pronounced. Moreover, the degree of variegation appears to be dependent on developmental stage and environmental factors, suggesting an intricate relationship between the different gene products. To explore this, developmental and light effects on the accumulation of FtsH protease were studied in wild‐type (WT) and FtsH2‐mutant plants. Whereas cotyledons of the mutant were indistinguishable from those of the WT, the first true leaves were almost completely white. Subsequent leaves contained increasing proportions of green sectors. Analysis of the mRNA of the four FtsH genes, in cotyledons, first and second leaves of WT and mutant plants, revealed that: (i) transcript level increases during development, and (ii) transcript level in the mutant is higher than in the WT. FtsH protein level in the mutant was ca. 50% of that found in the WT, whereas the levels of other thylakoid proteins were the same. In individual leaves, the level of FtsH protein increased during development as well. Exposure of seedlings to different light intensities did not affect the degree of variegation, suggesting that it is due to a defect in chloroplast development rather than photobleaching. Examination of FtsH protein during exposure to high light revealed a decrease in its level, concomitant with a decrease in PSII potential, suggesting that the kinetics of photoinhibition reflects not only photodamage to PSII and induction of protective mechanisms, but also a decrease in repair capacity due to a reduction in the level of FtsH protease.
The DOF protein, SAD, interacts with GAMYB in plant nuclei and activates transcription of endosperm‐specific genes during barley seed development
Authors: Diaz Isabel , Martinez Manuel , Isabel‐LaMoneda Ines , Rubio‐Somoza Ignacio , Carbonero Pilar
Published: May 2005

The DOF protein, SAD, previously shown to be a transcriptional activator in barley aleurone cells upon seed germination, also has an important role in gene regulation during endosperm development. mRNA was detected in early (10 days after flowering) developing barley seeds where it accumulated in the starchy endosperm, aleurone cells, nucellar projection, vascular tissues and the immature embryo, as shown by RT‐PCR and in situ hybridization analyses. The SAD protein, expressed in bacteria, binds to oligonucleotides containing the prolamine box, 5′‐A/TAAAG‐3′sequence, derived from the promoter regions of the endosperm‐specific genes Hor2 and Itr1, encoding a B‐hordein and trypsin‐inhibitor BTI‐CMe, respectively. SAD competed for the same binding sites with another endosperm‐expressed DOF protein, BPBF. Transient expression experiments in co‐bombarded developing endosperms demonstrated that SAD trans‐activated transcription from Hor2 and Itr1 promoters through binding to the intact DOF motifs. When the two DOF factors are co‐bombarded together an additive effect was observed upon the expression of the Itr1 gene. In‐frame fusion of the Sad ORF to the reporter green fluorescent protein gene directs the fluorescence expression to the nucleus in transiently transformed onion epidermal layers. The visualization of fluorescence in the nucleus of onion cells, using the bimolecular fluorescent complex (BiFC) approach, has shown the in vivo interaction between SAD and the R2R3MYB protein GAMYB. The interaction in plant cells has also been documented for the DOF protein BPBF and GAMYB, but nuclear interaction could not be detected between BPBF and SAD by this procedure.
Global transcript profiling of primary stems from Arabidopsis thaliana identifies candidate genes for missing links in lignin biosynthesis and transcriptional regulators of fiber differentiation
Authors: Ehlting Jürgen , Mattheus Nathalie , Aeschliman Dana S. , Li Eryang , Hamberger Britta , Cullis Ian F. , Zhuang Jun , Kaneda Minako , Mansfield Shawn D. , Samuels Lacey , Ritland Kermit , Ellis Brian E. , Bohlmann Jörg , Douglas Carl J.
Published: May 2005

Different stages of vascular and interfascicular fiber differentiation can be identified along the axis of bolting stems in Arabidopsis. To gain insights into the metabolic, developmental, and regulatory events that control this pattern, we applied global transcript profiling employing an Arabidopsis full‐genome longmer microarray. More than 5000 genes were differentially expressed, among which more than 3000 changed more than twofold, and were placed into eight expression clusters based on polynomial regression models. Within these, 182 upregulated transcription factors represent candidate regulators of fiber development. A subset of these candidates has been associated with fiber development and/or secondary wall formation and lignification in the literature, making them targets for functional studies and comparative genomic analyses with woody plants. Analysis of differentially expressed phenylpropanoid genes identified a set known to be involved in lignin biosynthesis. These were used to anchor co‐expression analyses that allowed us to identify candidate genes encoding proteins involved in monolignol transport and monolignol dehydrogenation and polymerization. Similar analyses revealed candidate genes encoding enzymes that catalyze missing links in the shikimate pathway, namely arogenate dehydrogenase and prephenate aminotransferase.
The nuclear gene HCF107 encodes a membrane‐associated R‐TPR (RNA tetratricopeptide repeat)‐containing protein involved in expression of the plastidial psbH gene in Arabidopsis
Authors: Sane Aniruddha P. , Stein Bernhard , Westhoff Peter
Published: May 2005

Expression of the genes of plastidial psbB operon (psbB‐psbT‐psbH‐petB‐petD) involves multiple processing events and formation of several mono‐, di‐ and multi‐cistronic transcripts which are further regulated by differential stability and expression. Here we describe the identification of the HCF107 gene that is involved in the 5′‐end processing/stability and/or translation of the psbH gene and in the translation of the psbB gene. HCF107 is an RNA‐TPR‐containing protein with 11 RTPRs that are tandemly arranged. A single mutation in the third RTPR that changes a conserved alanine residue to a threonine affects both 5′‐end‐processed psbH transcript accumulation as well as psbB translation, resulting in disruption of PSII and seedling lethal plants. The protein is localized to the plastid membranes and is present as part of a multi‐subunit complex in the range of 60–190 and 600–800 kDa. HCF107 thus represents a new member of the growing helical repeat family of proteins that seem to play a gene‐specific role in regulating plastidial gene expression and biogenesis.
EMBRYONIC FACTOR 1 encodes an AMP deaminase and is essential for the zygote to embryo transition in Arabidopsis
Authors: Xu Jun , Zhang Hai‐Ying , Xie Cong‐Hua , Xue Hong‐Wei , Dijkhuis Paul , Liu Chun‐Ming
Published: May 2005

Fusion of the egg and the sperm cells in plants produces a zygote that develops into an embryo. Screening of ethyl methanesulfonate‐mutagenized populations of Arabidopsis led to the identification of EMBRYONIC FACTOR 1 (FAC1), a locus that gives a zygote‐lethal phenotype when mutated. The FAC1 gene was identified by positional cloning and confirmed by a genetic complementation test against a T‐DNA insertion allele. It encodes an AMP deaminase (AMPD) that is known in human and yeast to convert AMP to IMP to maintain the energy potential. Expression of FAC1 in a yeast AMPD mutant after removal of its N‐terminal putative transmembrane domain complemented the mutant phenotype, suggesting a functional conservancy but a structural divergence through evolution. Although a low level of FAC1 expression was observed in all organs tested, using a reporter construct we observed a significantly increased FAC1 expression in the zygote, early embryo and endosperm. Furthermore, during somatic embryogenesis, a high level of FAC1 expression was observed in developing embryos including putative embryogenic cells. FAC1, therefore, represents one of the earliest expressed genes known in plants. It may act through AMP depletion to provide sufficient energy for the zygote to proceed through development.
Pesticide poisoning in south India: opportunities for prevention and improved medical management
Authors: Srinivas Rao CH. , Venkateswarlu V. , Surender T. , Eddleston Michael , Buckley Nick A.
Published: June 2005

Objective  Warangal district in Andhra Pradesh, southern India, records >1000 pesticide poisoning cases each year and hundreds of deaths. We aimed to describe their frequency and distribution, and to assess quality of management and subsequent outcomes from pesticide poisoning in one large hospital in the district.

Methods  We reviewed data on all patients admitted with pesticide poisoning to a district government hospital for the years 1997 to 2002. For 2002, details of the particular pesticide ingested and management were abstracted from the medical files.

Findings  During these 6 years, 8040 patients were admitted to the hospital with pesticide poisoning. The overall case fatality ratio was 22.6%. More detailed data from 2002 revealed that two‐thirds of the patients were <30 years old, 57% were male and 96% had intentionally poisoned themselves. Two compounds, monocrotophos and endosulfan, accounted for the majority of deaths with known pesticides in 2002. Low fixed‐dose regimens were used in the majority of cases for the most commonly used antidotes (atropine and pralidoxime). Inappropriate antidotes were also used in some patients.

Conclusions  It is likely that these findings reflect the situation in many rural hospitals of the Asia Pacific region. Even without an increase in resources, there appear to be significant opportunities for reducing mortality by better medical management and further restrictions on the most toxic pesticides.
Review: The phenothiazinium chromophore and the evolution of antimalarial drugs
Authors: Wainwright Mark , Amaral Leonard
Published: June 2005

The phenothiazinium salt methylene blue [3,7‐bis(dimethylamino)phenothiazinium chloride] is the oldest known synthetic antimalarial drug, its clinical efficacy having been reported in 1891. The role of methylene blue in the evolution of the modern antimalarial armoury is often unappreciated, yet it can be linked directly to standard drugs such as chloroquine and its congeners. Also, in the face of increasing plasmodial resistance to modern antimalarials, phenothiazinium derivatives have again featured as lead compounds in drug research. The precise mode of action of methylene blue and its commercial analogues against Plasmodium spp. remains a cause for conjecture, having been variously described as nucleic acid intercalation, food vacuole basification, parasite redox cycle interference and haem polymerization inhibition. That the activity of the series may be due to more than one route – i.e. a multifactorial activity – underlines the utility of these compounds in antimalarial research either as single drugs or as adjuvants (partners in a drug combination), particularly in the face of resistant parasitic strains.
Season, fever prevalence and pyrogenic threshold for malaria disease definition in an endemic area of Mali
Authors: Dicko Alassane , Mantel Carsten , Kouriba Boureima , Sagara Issaka , Thera Mahamadou A. , Doumbia Seydou , Diallo Mouctar , Poudiougou Belco , Diakite Mahamadou , Doumbo Ogobara K.
Published: June 2005

Background  Modelling malaria parasitaemia as function of fever has been proposed as best alternative to estimate the attributable fraction of malaria fever and the sensitivity and specificity of different case definitions of malaria disease.

Objectives  To determine the prevalence of fever and its relation to malaria parasitaemia and to establish a pyrogenic threshold for malaria disease in the area.

Methods  We conducted two cross‐sectional surveys in children of 6 months to 9 years of age (2434 during the rainy season of 1993 and 2353 during the dry season of 1994) randomly selected from 21 areas of Bandiagara district, Mali.

Results  The relationship between fever and Plasmodium falciparum parasitaemia depends strongly on the season, thus affecting the malaria‐attributable fraction of fever cases and the sensitivity and specificity of malaria case definitions. The overall proportion of fever attributable to malaria parasitaemia was 33.6% during the rainy season and 23.3% during the dry season, with the highest proportion occurring among the youngest children. The cut‐off value, where the sensitivity curve crosses the specificity curve, was around 3200 pf/μl for all age categories during the rainy season and 200 pf/μl during the dry season.

Conclusions  Malaria remains a main cause of fever in this area of Mali. The pyrogenic threshold of parasitaemia depends strongly on the season, and different cut‐off levels of parasitaemia should be used during the two seasons to define malaria cases in this area.
Short Communication: Palestinian infantile visceral leishmaniasis caused by a genetic variant of Leishmania infantum belonging to a new zymodeme
Authors: Bader Khaldoun A. , Schnur Lionel F. , Nasereddin Abedelmajeed , Pratlong Francine , Dedet Jean‐Pierre , Shaheen Loay , Yousef Obaida , Greenblatt Charles L.
Published: June 2005

The parasites causing a Palestinian case of infantile visceral leishmaniasis (IVL) and those from four dogs from the Jenin District were identified serologically, biochemically and molecular biologically as Leishmania infantum, showing dogs act as a reservoir. The strain from the human case was distinct because of its unique 200‐bp kDNA‐polymerase chain reaction (PCR) component in its restriction fragment length polymorphism (RFLP) profile after digestion with the endonuclease RsaI, and by the electrophoretic mobility of its malate dehydrogenase (MDH140), designating it the reference strain of a new zymodeme of L. infantum, MON‐281.
Molecular tracking of the lineage of strains of Vibrio cholerae O1 biotype El Tor associated with a cholera outbreak in Andaman and Nicobar Islands, India
Authors: Roy Subarna , Dutta Basabjit , Ghosh Asit Ranjan , Sugunan A. P. , Nandy Ranjan Kumar , Bhattacharya Sujit Kumar , Sehgal Subhash C.
Published: June 2005

A large outbreak of acute watery diarrhoea involving all age groups of mongoloid tribal aborigines occurred during October–November, 2002 in the Nancowry group of Andaman and Nicobar Islands in the Indian Ocean. Twenty‐one of the 67 stool samples from 67 patients were positive for toxigenic Vibrio cholerae O1, serotype Ogawa biotype El Tor, which showed striking similarity in its antibiogram with some of the strains of V. cholerae O1 Serotype Ogawa biotype El Tor isolated in Kolkata. The Nancowry and Kolkata isolates were compared with molecular tools involving random amplified polymorphic DNA (RAPD) fingerprinting, ribotyping and pulsed‐field gel electrophoresis (PFGE). RAPD fingerprinting and ribotyping techniques revealed that all the V. cholerae strains associated with the outbreak in these islands were clonal in nature and identical to a population of isolates obtained from Kolkata since 1993. PFGE could discriminate within these Kolkata isolates further and established that a particular subtype of this population reached the remote Nancowry islands and was responsible for the outbreak.
Associations between frequencies of a susceptible TNF‐α promoter allele and protective α‐thalassaemias and malaria parasite incidence in Vanuatu
Authors: Ubalee R. , Tsukahara T. , Kikuchi M. , Lum J. K. , Dzodzomenyo M. , Kaneko A. , Hirayama K.
Published: June 2005

Tumour necrosis factor‐alpha (TNF‐α) is one of the key cytokines that influence the pathology of microbial infections. The genetic susceptibility to severe forms of falciparum malaria is differentially associated with TNF‐α promoter gene polymorphisms (TNFP alleles). In a previous study, we identified a TNFP‐allele characterized by a C to T transition at position −857 (TNFP‐D allele) as a marker for susceptibility to cerebral malaria in Myanmar. The frequencies of TNFP alleles on six islands of Vanuatu, Melanesia (South‐west Pacific) were estimated to investigate whether malaria selection pressure on this susceptibility marker has influenced its prevalence. Within the archipelago of Vanuatu there is a decreasing cline of parasite incidence from North to South. Of the four alleles of the TNFP gene detected in Vanuatu, the TNFP‐D allele frequencies were inversely correlated with the parasite incidence of islands; TNFP‐D varied from 0.55 on the island with the lowest parasite incidence to 0.26 on the island with the highest parasite incidence (r = −0.855, P = 0.03). We also observed a significant correlation between the frequencies of α‐thalassaemia alleles, thought to protect against malaria and parasite incidence in the same populations. These data are consistent with a previously reported correspondence between the frequencies of glucose 6‐phosphate dehydrogenase (G6PD) deficiency and parasite incidences on the islands of Vanuatu (Kaneko et al. 1998) and indicate that the degree of malaria endemicity has influenced the allele frequencies of at least three loci that confer both susceptibility (TNFP‐D) and protection (α‐thalassaemias and G6PD deficiency).
A randomized, placebo‐controlled, double‐blind trial on sulfadoxine–pyrimethamine alone or combined with artesunate or amodiaquine in uncomplicated malaria
Authors: Mockenhaupt Frank P. , Ehrhardt Stephan , Dzisi Stephen Y. , Teun Bousema J. , Wassilew Nasstasja , Schreiber Jonas , Anemana Sylvester D. , Cramer Jakob P. , Otchwemah Rowland N. , Sauerwein Robert W. , Eggelte Teunis A. , Bienzle Ulrich
Published: June 2005

The therapeutic efficacy of sulfadoxine–pyrimethamine (SP) alone, SP plus amodiaquine (AQ), and SP plus artesunate (AS) was assessed in a randomized, placebo‐controlled, and double‐blind trial among 438 children with uncomplicated Plasmodium falciparum malaria in northern Ghana. Clinical and parasitological responses were monitored for 28 days following treatment; 86%, 98% and 97% of SP‐, SP + AQ‐, and SP + AS‐treated patients achieved adequate clinical and parasitological response (ACPR) within 2 weeks, respectively. Parasite clearance was better with SP + AS than with SP or SP + AQ treatment but re‐infections were more common. Polymerase chain reaction (PCR)‐corrected rates of ACPR at day 28 were 72.2% for SP, 94.1% for SP + AQ (P < 0.0001), and 94.5% for SP + AS (P < 0.0001). Gametocyte prevalence and density 1 week after treatment were highest in children treated with SP, and lowest in patients receiving SP + AS. No severe adverse events attributable to study medication were observed. In northern Ghana, more than one of four children suffered SP treatment failure within 4 weeks. Both SP + AQ and SP + AS are efficacious alternative therapeutic options in this region. Although SP + AS and SP + AQ treatments have virtually identical cure rates, rapid parasite clearance and pronounced gametocidal effects are the advantages of the former, whereas cost and a lower rate of late re‐infections are those of the latter.
Effects of ambient versus reduced UV‐B radiation on high arctic Salix arctica assessed by measurements and calculations of chlorophyll a fluorescence parameters from fluorescence transients
Authors: Albert Kristian R. , Mikkelsen Teis N. , Ro‐Poulsen Helge
Published: May 2005

A UV‐B exclusion‐experiment was conducted in the high Arctic Zackenberg, NE Greenland, in which Salix arctica leaves during most of the growing season were fixed perpendicular to the solar zenith angle, thereby receiving maximal solar radiation. Covered with Teflon and Mylar foil, the leaves received approximately 90 and 40% of the ambient UV‐B irradiance, respectively. The effects were examined through recordings of chlorophyll a fluorescence transients, determination of biomass and analysis of total carbon and nitrogen content and amount of soluble flavonoids in the leaves. The processing of light was analysed by means of the chlorophyll a fluorescence transient, using the so‐called JIP test, as evolved by Reto J. Strasser and his coworkers. Reduction of the UV‐B irradiance caused a rise in many of the fluorescence parameters during July, but not in August (late season). Thus increases in the efficiency that an absorbed photon will be trapped by the PSII reaction centre with the resultant reduction of QA to QA– (ET0/ABS = FV/FM) and the efficiency that an electron residing on QA– will enter the intersystem electron transport chain (ET0/TR0) were observed in reduced UV‐B. Moreover, estimated per cross‐section of leaf sample, the number of active PSII reaction centres (RC/CSM) and electron transport rate (ETM/CSM) and all performance indexes (PIABS, PICSo and PICSm) were increased in reduced UV‐B. The total soluble flavonoid content was highest in ambient UV‐B. The treatment effects on fluorescence parameters that were directly measured (e.g. F0 and FM) and those that were derived (e.g. quantum efficiencies, parameters per PSII reaction centres and per cross‐section of leaf sample) are discussed in relation to one another, in relation to daily and seasonal variation, and from the perspective of evaluating the relative importance of UV‐B of donor and acceptor side capacity in Photosystem II. In conclusion, the experimental set‐up and non‐invasive measurements proved to be a sensitive method to screen for effects of UV‐B stress.
Differential inhibition of photosynthesis during pre‐flowering drought stress in Sorghum bicolor genotypes with different senescence traits
Authors: Beyel Volker , Brüggemann Wolfgang
Published: May 2005

Young (16‐day‐old) Sorghum bicolor plants of a late‐ and slow‐senescing Texas A&M line (B 35) and of an early‐ and fast‐senescing descendant of an Ethiopian landrace (E 36‐1) were subjected to drought stress by decreasing the soil water content to 30% field capacity over 6 days. Plant water potentials decreased from − 2 bar (controls) to − 10 to − 18 bar, and this drought stress resulted in: (1) differential phenotypic reactions and (2) differential decreases in photosynthesis rates in the two cultivars. While E 36‐1 tended to lose viable leaf area from the leaf tips downwards, B 35 showed a gradual overall drying of the leaf. At the same time, photosynthesis rates decreased from 31.5 ± 1.6 to 12.3 ± 5.0 µmol CO2 m−2 s−1 (E 36‐1) and from 30.5 ± 1.6 to 3.3 ± 2.6 µmol CO2 m−2 s−1 (B 35), respectively. In vitro enzyme activities of phosphoenolpyruvate carboxylase (PEPCase), malate dehydrogenase (MDH) and malic enzyme (ME) on a leaf area basis exceeded the photosynthesis rates. Pyruvate phosphate dikinase (PPDK) activity was close to the photosynthesis rates in control plants and higher than the photosynthesis rates in drought‐stressed plants. Thus, none of the enzymes appeared to limit photosynthesis under drought stress, and likely bottleneck enzyme activities of the C3 pathway in the bundle‐sheath cells, i.e. ribulose‐1,5‐bisphosphate carboxylase (RubisCO) and stromal fructose‐1,5‐bisphosphatase (sFBPase), also showed sufficient activities to sustain higher photosynthesis rates than those observed in the stressed plants. However, under drought stress, total leaf malate concentrations were higher in B 35 (up to 33.1 µmol g−1 FW) than in E 36‐1 (up to 22.4 µmol g−1 FW). In particular, at the presumed cytosolic pH of 7.0–7.3, S. bicolor PEPCase was strongly inhibited by malate. In contrast with the in vitro PEPCase enzyme activities, the A/Ci curves suggested a stronger decrease in the in vivo activity of the enzyme in B 35 under drought stress than in E 36‐1. It is therefore suggested that photosynthesis under drought stress may be inhibited differentially through feedback malate inhibition of PEPCase in S. bicolor.
Physiology of maize II: Identification of physiological markers representative of the nitrogen status of maize (Zea mays) leaves during grain filling
Authors: Hirel Bertrand , Andrieu Bruno , Valadier Marie‐Hélène , Renard Sylvain , Quilleré Isabelle , Chelle Michael , Pommel Bernard , Fournier Christian , Drouet Jean‐Louis
Published: May 2005

To illustrate the development of the source‐to‐sink transition in maize leaves during the grain‐filling period, an integrated physiological‐agronomic approach is presented in this study. The evolution of physiological markers such as total leaf nitrogen (N), chlorophyll, soluble protein, amino acid and ammonium contents was monitored from silking to a period close to maturity in different leaf stages of three maize genotypes grown at high and low levels of N fertilization. In addition, the activities of glutamine synthetase (GS) and glutamate dehydrogenase (GDH), two enzymes known to play a direct or an indirect role during leaf N remobilization, were measured. In the three genotypes examined, we found that a general decrease of most metabolic and enzyme markers occurred during leaf ageing and that this decrease was enhanced when plants were N starved. In contrast, such variations were not observed between different sections of a single leaf even at an advanced stage of leaf senescence. We found that there is a strong correlation between total N, chlorophyll, soluble protein and GS activity, which is not dependent upon the N fertilization level, which indicates the N status of the plant, either in a single leaf or during ageing. In contrast, ammonium, amino acids and GDH activity were not subject to such variations, thus suggesting that they are indicators of the metabolic activity of the whole plant in response to the level of N fertilization. The use of these markers to predict the N status of maize as a function of both plant development and N availability is discussed.
Induction of enhanced disease resistance and oxidative stress tolerance by overexpression of pepper basic PR‐1 gene in Arabidopsis
Authors: Hong Jeum Kyu , Hwang Byung Kook
Published: May 2005

The pathogen‐ and ethylene‐inducible pepper‐basic pathogenesis‐related (PR)‐1 gene, CABPR1, was strongly expressed in pepper leaves by osmotic and oxidative stresses. The pepper CABPR1 was introduced into the Arabidopsis plants under the control of the cauliflower mosaic virus 35S promoter. Polymerase chain reaction‐amplification with the Arabidopsis genomic DNA and Northern blot analyses confirmed that the pepper CABPR1 gene was integrated into the Arabidopsis genome, where it was overexpressed in the transgenic Arabidopsis plants under normal growth conditions. The constitutive overexpression of CABPR1 induced the expression of the Arabidopsis PR‐genes including PR‐4, PR‐5 and PDF1.2. Enhanced resistance to phytopathogenic bacteria, Pseudomonas syringae pv. tomato DC3000, was also observed in the transgenic Arabidopsis plants. CABPR1 overexpression in the transgenic Arabidopsis caused enhanced seed germination under NaCl (ionic) and mannitol (non‐ionic) osmotic stresses. Enhanced tolerances to high salinity and dehydration stresses during seed germination of the transgenic plants were not found at the early seedling stage. The transgenic Arabidopsis plants exhibited a higher tolerance to oxidative stress by methyl viologen at the seed germination, seedling and adult plant stages. These results suggest that the CABPR1 gene may function in the enhanced disease resistance and oxidative stress tolerance of transgenic Arabidopsis plants.
A World Health Organization International Standard for hepatitis A virus RNA nucleic acid amplification technology assays
Authors: Saldanha J. , Heath A. , Lelie N. , Pisani G. , Yu M.‐Y. ,   the Collaborative Study Group
Published: June 2005

Background and Objectives Sixteen laboratories from 10 different countries participated in an international collaborative study to evaluate candidate materials as the first World Health Organization (WHO) International Standard for hepatitis A virus (HAV) RNA nucleic acid amplification technology (NAT) assays.

Materials and Methods Five candidate materials were analysed in this study: materials AA and BB were lyophilized, while materials CC, DD and EE were liquid preparations. Samples were diluted in pooled plasma or in pooled cryo‐poor plasma (sample EE). Serial dilutions of the candidate materials were tested by each laboratory in four independent assays and the results were analysed statistically.

Results The mean log10‘equivalents’ per ml were 5·29 for sample AA, 5·07 for sample BB, 4·99 for sample CC, 5·40 for sample DD and 4·08 for sample EE.

Conclusions Based on the results of this study, sample AA was established as the first International Standard for HAV RNA NAT assays at the WHO Expert Committee on Biological Standardizaton (ECBS) meeting held in February 2003. The code number of this preparation is 00/560 and the potency, based on the study, is 100 000 International Units (IU)/ml.
Interlaboratory comparison of red‐cell ATP, 2,3‐diphosphoglycerate and haemolysis measurements
Authors: Hess J. R. , Kagen L. R. , Van Der Meer P. F. , Simon T. , Cardigan R. , Greenwalt T. J. , AuBuchon J. P. , Brand A. , Lockwood W. , Zanella A. , Adamson J. , Snyder E. , Taylor H. L. , Moroff G. , Hogman C.
Published: June 2005

Background and Objectives  Red blood cell (RBC) storage systems are licensed based on their ability to prevent haemolysis and maintain RBC 24‐h in vivo recovery. Preclinical testing includes measurement of RBC ATP as a surrogate for recovery, 2,3‐diphosphoglycerate (DPG) as a surrogate for oxygen affinity, and free haemoglobin, which is indicative of red cell lysis. The reproducibility of RBC ATP, DPG and haemolysis measurements between centres was investigated.

Materials and Methods  Five, 4‐day‐old leucoreduced AS‐1 RBC units were pooled, aliquotted and shipped on ice to 14 laboratories in the USA and European Union (EU). Each laboratory was to sample the bag twice on day 7 and measure RBC ATP, DPG, haemoglobin and haemolysis levels in triplicate on each sample. The variability of results was assessed by using coefficients of variation (CV) and analysis of variance.

Results  Measurements were highly reproducible at the individual sites. Between sites, the CV was 16% for ATP, 35% for DPG, 2% for total haemoglobin and 54% for haemolysis. For ATP and total haemoglobin, 94 and 80% of the variance in measurements was contributed by differences between sites, and more than 80% of the variance for DPG and haemolysis measurements came from markedly discordant results from three sites and one site, respectively. In descending order, mathematical errors, unvalidated analytical methods, a lack of shared standards and fluid handling errors contributed to the variability in measurements from different sites.

Conclusions  While the methods used by laboratories engaged in RBC storage system clinical trials demonstrated good precision, differences in results between laboratories may hinder comparative analysis. Efforts to improve performance should focus on developing robust methods, especially for measuring RBC ATP.
Frequencies of maternal platelet alloantibodies and autoantibodies in suspected fetal/neonatal alloimmune thrombocytopenia, with emphasis on human platelet antigen‐15 alloimmunization
Authors: Mandelbaum M. , Koren D. , Eichelberger B. , Auerbach L. , Panzer S.
Published: June 2005

Background and Objectives Serological evaluation of maternal sera for platelet antibodies in suspected fetal/neonatal alloimmune thrombocytopenia (FNAITP) discloses in only ≈ 30% of individuals a platelet‐specific antibody. Transfusion‐induced alloimmunization against human platelet antigen‐15 (HPA‐15) has been reported to be about as common as against HPA‐5, the second most common platelet antibody. Thus, anti‐HPA‐15 may also contribute significantly to yet‐unclear cases of FNAITP.

Materials and Methods In this retrospective analysis, we provide data on maternal platelet antibodies from 309 mothers who delivered an offspring with suspected FNAITP.

Results Genotyping maternal and paternal samples (together n = 573) revealed a gene frequency of 0·496 for HPA‐15a and a gene frequency of 0·504 for HPA‐15b. HPA‐15 antibodies were detected in 2% of all samples. Anti‐HPA‐15a and ‐15b were detected in two and three samples, respectively. One serum reacted equally with HPA‐15a and ‐15b platelets. The most frequent platelet‐specific antibodies were anti‐HPA‐1a (22%), but anti‐HPA‐5b (8·4%) were more frequent than anti‐HPA‐15. In addition, panreactive (5·5%) or autoreactive (5·2%) anti‐GPIIb/IIIa or anti‐GPIb/IX were detectable in maternal samples.

Conclusions These data indicate that HPA‐15 alloimmunization needs only to be considered in subjects with suspected FNAITP if no other platelet‐specific antibody is detectable. The presence of panreactive or autoreactive antibodies should also be considered in neonatal thrombocytopenia.
Influence of site factors on the impact of Phytophthora cinnamomi in cork oak stands in Portugal
Authors: Moreira A. C. , Martins J. M. S.
Published: May 2005

Although decline of cork (Quercus suber) and holm oak trees (Quercus rotundifolia) has been described in Portugal in the late years of the 19th century, its development has become a motive of high concern during the last two decades. The presence of Phytophthora cinnamomi in cork and holm oak stands was surveyed in four different regions of the country (Trás‐os‐Montes, Alentejo, Ribatejo and Algarve) during 1995–98. Tree decline severity, sudden death and site characteristics were assessed in 56 sites representing varied conditions. The pathogen was isolated from oak roots and rhizosphere samples in 27 of those places. Other plant species from natural vegetation were sampled in three active disease centres. This survey showed that 56% of the surveyed species of shrub flora were infected with P. cinnamomi, which was detected mainly on species belonging to the families Ericaceae, Cistaceae and Leguminosae. Recovery of P. cinnamomi was more frequent in shallow soils (Leptosols and complex Leptosols and Luvisols). These soils are more common in the south (Algarve), where decline has a high impact. Soils with low fertility and low mineral nutrient levels, particularly phosphorus, seemed to favour infection. Site aspect and topographic tree situation were also evaluated. Sites facing south showed higher occurrence of P. cinnamomi, which was also more frequent in slopes and valleys than on hilltops. In Algarve, a relationship could be established between the crown status and the presence of P. cinnamomi in roots and rhizosphere. Different morphotypes of P. cinnamomi could be distinguished in vitro, and their occurrence in the field was correlated with particular site characteristics. Further research needs and management strategies to limit the extension of the disease are discussed.
Variation among Italian and French elm clones in their response to Ophiostoma novo‐ulmi inoculation
Authors: Santini A. , Fagnani A. , Ferrini F. , Ghelardini L. , Mittempergher L.
Published: May 2005

In 1995 a clone bank of elms from across Italy was created at Antella (Florence, I) under a European Union project. In 1998 an experimental planting of some clones from this source was established in Antella together with material from a similar clone bank in France and two reference clones: Commelin (relatively susceptible) and Lobel (relatively resistant). In May 2001, the elms were inoculated with Ophiostoma novo‐ulmi and disease development was assessed throughout that summer and the next. Significant differences in susceptibility were found between taxonomic groups, with putative natural hybrids between Ulmus minor and Ulmus pumila being the most resistant and Ulmus glabra the most susceptible. Significant differences were also found within U. minor, some clones being as resistant as Lobel. For U. minor, a statistically significant relation was found with latitude, southerly clones showing less disease than more northerly ones. Relationships were also found between disease severity and times to bud burst, these relationships applying both to the different taxonomic groups and within U. minor. Relationships between growth increment and disease severity were inconsistent. These results are discussed in relation to the intrinsic genetically‐controlled differences that exist between elms and to differences in susceptibility that occur as the growing season proceeds and as a consequence of environmental influences.
Effects of Clinical Mastitis on Ovarian Function in Post‐partum Dairy Cows
Authors: Huszenicza Gy , Jánosi Sz , Kulcsár M , Kóródi P , Reiczigel J , Kátai L , Peters AR , De Rensis F
Published: June 2005

Contents

Mastitis‐induced ovarian abnormalities were studied in a field trial. At 1–3 day after calving, ≥2 parity cows not affected with chronic recurrent mastitis and yielding <400 000/ml somatic cell count (SCC) individual milk in the previous lactation, were enrolled in the study. Thereafter milk samples were collected three times weekly for 95–100 day for progesterone (P4) assay. Individual P4 profiles were used to monitor ovarian cyclicity. When mastitis was diagnosed in the first 80 day post‐partum (pp), clinical signs were recorded and scored, and aseptic milk samples were taken to identify the mastitis pathogens. Depending on the isolated pathogens the cows were blocked into one of the three sub‐groups affected by either Gram‐positive (GP), or Gram‐negative (GN) bacteria, or of those with no detected pathogens (NDP). Cows suffering from any type of mastitis between days 15 and 28 (n = 27) showed a delay in the onset of ovarian cyclicity, and estrus was postponed compared to cows affected during the first 14 day pp (n = 59) and controls (n = 175) (38.6 ± 2.3 vs 33.4 ± 2.1 and 32.0 ± 1.0 day, respectively, for onset of ovarian cyclicity and 90.7 ± 2.5 vs 80.2 ± 2.8 and 83.9 ± 2.1 day, respectively, for estrus; both p < 0.05). The percentage of cows ovulating by day 28 was lower in those affected by mastitis between days 14 and 28 compared to cows between days 1 and 14 and controls (22.2% vs 47.5 and 50.3%, respectively; p < 0.05). A significantly higher rate of premature luteolysis was observed in GN + NDP compared to GP mastitis and healthy cows (46.7% vs 8.3 and 2.0%, respectively; p < 0.001). If the mastitis outbreak occurred during the follicular phase, the duration of this cycle segment was lengthened in GN + NDP mastitis compared to GP mastitis and healthy cows (10.8 ± 0.9 vs 7.9 ± 0.1 and 7.2 ± 0.1, respectively; p < 0.001). The results indicate that mastitis can affect the resumption of ovarian activity in pp dairy cows. Mastitis may also impair reproduction also in cyclic cows: this effect can be the consequence of premature luteolysis or a prolonged follicular phase.
Relation between Physical Properties of the Zona Pellucida and Viability of Bovine Embryos after Slow‐freezing and Vitrification
Authors: Moreira da Silva F , Metelo R
Published: June 2005

Contents

In vitro‐produced bovine morulae/blastocyst embryos (n = 119) were slow‐frozen and vitrified and the physical alterations of the zona pellucida (ZP) was observed by scanning electron microscopy (SEM) to find an explanation for the loss of developmental capacity of the embryos after freezing/thawing. A control group was provided, in which embryos (n = 38) were neither frozen nor vitrified. Embryos were in vitro‐cultured in a standard CO2 Heraeus incubator and their viability was assessed 24 and 48 h after the start of culture, evaluating their morphological aspect. After 24 h of culture, embryo survival rate for slow‐freezing/thawed (n = 23), vitrified/thawed (n = 20) and control embryos (n = 20) was 39, 27 and 90%, and 35, 14 and 65% after 48 h of culture, respectively. For evaluation of physical changes occurring in ZP, 20 embryos were slow‐frozen, 18 were vitrified and 18 were used as control. All embryos were fixed, dried and examined under an SEM. Embryo's diameter, as well as the number of pores and their diameter was measured in squares of 6.4 μm width. We observed that, on average, the diameter of the embryos (92.26 ± 10.15 μm) did not differ significantly among all embryos. As far as the diameter of the pores in the outer surface of the ZP is concerned, the results revealed a significant difference (P < 0.05) between control (0.48 ± 0.0025 μm), slow‐frozen (0.34 ± 0.0007 μm) and vitrified (0.27 ± 0.0006 μm) embryos. For the number of pores, statistical differences (p < 0.05) were observed between control and vitrified embryos (45.4 ± 7.3 vs 38.2 ± 8.2). It is possible that ZP functions as a barrier which is positive when dealing with pathogens, but is harmful when nutrients were supplied from the outside, especially at 48 h of culture. Results indicate that the steps of cryopreservation cause alterations in ZP, with irreversible damage on the further developmental competence of bovine embryos.
Leptin, GH, PRL, Insulin and Metabolic Parameters Throughout the Dry Period and Lactation in Dairy Cows
Authors: Accorsi PA , Govoni N , Gaiani R , Pezzi C , Seren E , Tamanini C
Published: June 2005

Contents

Leptin may play a role in the endocrine‐metabolic processes that guarantee the physiological course of lactation in dairy cattle. This study was aimed at determining the changes in plasma concentrations of leptin and some of the main hormones and metabolites involved in the lactogenetic process in high‐yielding dairy cows throughout lactation; we also wanted to assess whether leptin secretion is subjected to seasonal influences. Blood samples were collected from 23 Italian Friesian dairy cows from the end of a lactation to the ninth month of the subsequent one; in addition, blood was sampled from 47 dairy cows in different phases of lactation during February and July. Plasma concentrations of leptin, growth hormone (GH), insulin, prolactin (PRL), glucose, non‐esterified fatty acids (NEFA) and urea were quantified by either validated radioimmunoassay (RIA) or enzymatic colorimetric methods. At the beginning of lactation, GH concentrations significantly increased, while a significant reduction occurred in leptin and insulin. This endocrine condition, such as the significant increase in NEFA plasma concentrations, is indicative of a marked lipid mobilization. In the more advanced stages of lactation, when both energy and protein balances become positive, leptin plasma concentrations increased, whereas GH and NEFA concentrations declined. During the summer months, a significant increase in leptin plasma concentrations, irrespective of the phase of lactation, was observed. Collectively, our findings suggest that, in dairy cows, leptin may represent a ‘metabolic signal’ of animal's status of fattening and nutritional level; in addition, leptin seems to be influenced by photoperiod and environmental temperature.