bluuebunny/crossref_metadata_2025 huggingface dataset:
A lipochito‐oligosaccharide, Nod factor, induces transient calcium influx in soybean suspension‐cultured cells
Authors: Yokoyama Tadashi , Kobayashi Naoki , Kouchi Hiroshi , Minamisawa Kiwamu , Kaku Hisatoshi , Tsuchiya Kenichi
Published: March 2003

Lipochito‐oligosaccharides (Nod factors) produced by Rhizobium or Bradyrhizobium are the key signal molecules for eliciting nodulation in their corresponding host legumes. To elucidate the signal transduction events mediated by Nod factors, we investigated the effects of Nod factors on the cytosolic [Ca2+] of protoplasts prepared from roots and suspension‐cultured cells of soybean (Glycine max and G. soja) using a fluorescent Ca2+ indicator, Fura‐PE3. NodBj‐V (C18:1, MeFuc), which is a major component of Nod factors produced by Bradyrhizobium japonicum, induces transient elevation of cytosolic [Ca2+] in the cells of soybean within a few minutes. This effect is specific to soybean cells and was not observed in the tobacco BY‐2 cells. Furthermore, NodBj‐V without MeFuc did not induce any cytosolic [Ca2+] elevation in soybean cells. Exclusion of Ca2+ from the medium, as well as pre‐treatment of the cells with an external Ca2+ chelator or with a plasma membrane voltage‐dependent Ca2+ channel inhibitor, suppressed the Nod factor‐dependent cytosolic [Ca2+] elevation. These results indicate that transient Ca2+ influx from extracellular fluid is one of the earliest responses of soybean cells to NodBj‐V (C18:1, MeFuc) in a host‐specific manner.
Cell division events are essential for embryo patterning and morphogenesis: studies on dominant‐negativecdc2aAtmutants ofArabidopsis
Authors: Hemerly Adriana S. , Ferreira Paulo C. G. , Van Montagu Marc , Engler Gilbert , Inzé Dirk
Published: March 2003

During plant development, cell division events are coordinately regulated, leading to specific growth patterns. Experimental evidence indicates that the morphogenetic controls that act at the vegetative plant growth stage are flexible and tolerate distortions in patterns and frequencies of cell division. To address questions concerning the relationship between cell division and embryo formation, a novel experimental approach was used. The frequencies of cell division were reduced exclusively during embryo development ofArabidopsisby the expression of a dominantcdc2amutant. The five independent transgenic lines with the highest levels of the mutantcdc2aaffected embryo formation. In the C13 line, seeds failed to germinate. The C1, C5 and C12 lines displayed a range of distortions on the apical–basal embryo pattern. In the C3 line, the shoot apical meristem of the seedlings produced leaves defective in growth and with an incorrect phyllotactic pattern. The results demonstrate that rates of cell division do not dictate cellular differentiation of embryos. Nevertheless, whereas cell divisions are uncoupled from vegetative development, they are instrumental in elaborating embryo structures and modulating embryo and seedling morphogenesis.
The gene fimbriata interacts non‐cell autonomously with floral regulatory genes
Authors: Schultz Elizabeth , Carpenter Rosemary , Doyle Sandra , Coen Enrico
Published: March 2003

In Antirrhinum majus, one proposed role of the gene fimbriata (fim) is as a mediator between the floral meristem identify gene floricaula (flo) and floral organ identity genes such as deficiens (def) and plena (ple). The mechanism of fim activity is probably unique as, while the other genes in the hierarchy are thought to be transcription factors, fim is thought to target proteins to a ubiquitin‐mediated destruction pathway. Both flo and def have been shown to act non‐cell autonomously. We tested the hypotheses that (i) fim acts in a non‐cell autonomous manner; and (ii) non‐cell autonomy of flo might be through activation and subsequent non‐cell autonomous activity of fim. Plants bearing an unstable fim allele were monitored for revertant shoots. Analysis of fim RNA expression in plants derived from revertant shoots, and segregation of revertant phenotype in progeny from revertant plants, indicated that all were periclinal chimeras with wild‐type fim expression only in subepidermal layers. Despite the absence of fim in the epidermal layer, expression of downstream genes was normal, suggesting non‐cell autonomous activity of fim. Subsequently, we tested the hypothesis that fim is the mediator of flo non‐cell autonomy by examining fim expression in flo periclinal chimeras. In these chimeras, fim is activated in cells where flo is not expressed, indicating that fim cannot be the sole mediator of flo non‐cell autonomy.
Auxin distribution and transport during embryonic pattern formation in wheat
Authors: Fischer‐Iglesias Christiane , Sundberg Björn , Neuhaus Gunther , Jones Alan Munte
Published: March 2003

Inhibitors of auxin polar transport disrupt normal embryogenesis and thus specific spatial auxin distribution due to auxin movement may be important in establishing embryonic pattern formation in plants. In the present study, the distribution of the photoaffinity labeling agent tritiated 5‐azidoindole‐3‐acetic acid ([3H],5‐N3IAA), an analog of indole‐3‐acetic acid (IAA), was visualized in zygotic wheat (Triticum aestivum L.) embryos grown in vitro and in planta, and used to deduce auxin transport pathways in these embryos. This study provides the first direct evidence that the distribution of auxin, here [3H],5‐N3IAA, is heterogeneous and changes during embryo development. In particular, the shift from radial to bilateral symmetry was correlated with a redistribution of [3H],5‐N3IAA in the embryo. Furthermore, in bilaterally symmetrical embryos, that is, embryos in the late transition stage or older, the localization of [3H],5‐N3IAA was altered by N‐1‐naphthylphthalamic acid, a specific inhibitor of auxin polar transport. No significant effect was observed in radially symmetrical embryos, that is, globular embryos, or very early transition embryos. Thus, the shift from radial to bilateral symmetry is associated with the onset of active, directed auxin transport involved in auxin redistribution. A change in the distribution of [3H],5‐N3IAA was also observed in morphologically abnormal embryos induced on media supplemented with auxin or auxin polar transport inhibitors. By means of a microscale technique, free IAA concentration was measured in in vitro‐ and in planta‐grown embryos and was found to increase during development. Therefore, IAA may be synthesized or released from conjugates in bilaterally symmetrical embryos, although import from surrounding tissues cannot be excluded.
Arabidopsis IRT2 gene encodes a root‐periphery iron transporter
Authors: Vert Grégory , Briat Jean‐François , Curie Catherine
Published: March 2003

Iron uptake from the soil is a tightly controlled process in plant roots, involving specialized transporters. One such transporter, IRT1, was identified in Arabidopsis thaliana and shown to function as a broad‐range metal ion transporter in yeast. Here we report the cloning and characterization of the IRT2 cDNA, a member of the ZIP family of metal transporters, highly similar to IRT1 at the amino‐acid level. IRT2 expression in yeast suppresses the growth defect of iron and zinc transport yeast mutants and enhances iron uptake and accumulation. However, unlike IRT1, IRT2 does not transport manganese or cadmium in yeast. IRT2 expression is detected only in roots of A. thaliana plants, and is upregulated by iron deficiency. By fusing the IRT2 promoter to the uidA reporter gene, we show that the IRT2 promoter is mainly active in the external cell layers of the root subapical zone, and therefore provide the first tissue localization of a plant metal transporter. Altogether, these data support a role for the IRT2 transporter in iron and zinc uptake from the soil in response to iron‐limited conditions.
HSR203 antisense suppression in tobacco accelerates development of hypersensitive cell death
Authors: Tronchet Maurice , Ranty Benoît , Marco Yves , Roby Dominique
Published: March 2003

Activation of the tobacco gene hsr203 is rapid, highly localized, specific for incompatible plant–pathogen interactions, and strongly correlated with programmed cell death occurring in response to diverse pathogens. Functional characterization of hsr203 gene product has shown that HSR203 is a serine hydrolase that displays esterase activity. We show here that transgenic tobacco plants deficient in HSR203 protein exhibit an accelerated hypersensitive response when inoculated with an avirulent strain of Ralstonia solanacearum. This response was accompanied by a maximal level of cell death and a drastic inhibition of in planta bacterial growth. Transgenic plants deficient in HSR203 were also found to show increased resistance in a dosage‐dependent manner to Pseudomonas syringae pv. pisi, another avirulent bacterial pathogen, and to virulent and avirulent races of Phytophthora parasitica, a fungal pathogen of tobacco, but not to different virulent bacteria. Surprisingly, expression of another hsr gene, hsr515, and that of the defence genes PR1‐a and PR5, was strongly reduced in the transgenic lines. Our results suggest that hsr203 antisense suppression in tobacco can have pleiotropic effects on HR cell death and defence mechanisms, and induces increased resistance to different pathogens.
A cell‐cycle‐regulated kinase activity phosphorylates plant retinoblastoma protein and contains, in Arabidopsis, a CDKA/cyclin D complex
Authors: Boniotti Maria Beatrice , Gutierrez Crisanto
Published: March 2003

The activity of cyclin‐dependent kinases (CDK) is crucial for cell‐cycle transitions. Here, we report the identification of a CDK activity that phosphorylates the retinoblastoma‐related (RBR) protein. A CDK/cyclin complex that binds to and phosphorylates RBR may be isolated from various plant sources, e.g. wheat, maize, Arabidopsis thaliana and tobacco, and from cells growing under various conditions. The presence of an RBR‐associated CDK activity correlates with the proliferative activity, suggesting that phosphorylation of RBR is a major event in actively proliferating tissues. In A. thaliana, this activity comprises a PSTAIRE CDKA and at least cyclin D2. Furthermore, this CDK activity is cell‐cycle‐regulated, as revealed by studies with highly synchronized tobacco BY‐2 cells where it is maximal in late G1 and early S phase cells and progressively decreases until G2 phase. Aphidicolin‐arrested but not roscovitine‐arrested cells contain a PSTAIRE‐type CDK that binds to and phosphorylates RBR. Thus, association with a D‐type cyclin is a likely mechanism leading to CDK activation late in G1. Our studies constitute the first report measuring the activity of CDK/cyclin complexes formed in vivo on RBR, an activity that fluctuates in a cell‐cycle‐dependent manner. This work provides the basis for further studies on the impact of phosphorylation of RBR on its function during the cell cycle and development.
Involvement of extracellular calcium influx in the self‐incompatibility response of Papaver rhoeas
Authors: Franklin‐Tong Vernonica E. , Holdaway‐Clarke Terena L. , Straatman Kornelis R. , Kunkel Joseph G. , Hepler Peter K.
Published: March 2003

We have previously demonstrated that increases in cytosolic free Ca2+ are triggered by the self‐incompatibility (SI) response in incompatible Papaver rhoeas (the field poppy) pollen. However, one key question that has not been answered is whether extracellular Ca2+ may be involved. To address this question, we have used an ion‐selective vibrating probe to measure changes in extracellular Ca2+ fluxes around poppy pollen tubes. Our data reveal several findings. First, we confirm that there is an oscillating Ca2+ influx directed at the apex of the pollen tube; we also provide evidence that Ca2+ influx also occurs at the shanks of pollen tubes. Second, upon challenge with self‐incompatibility (S) proteins, there is a stimulation of Ca2+ influx along the shank of incompatible pollen tubes, approximately 50 µm behind the pollen tube tip. This demonstration of SI‐induced Ca2+ influx suggests a role for influx of extracellular Ca2+ in the SI response.
Position dependent expression of GL2‐type homeobox gene, Roc1: significance for protoderm differentiation and radial pattern formation in early rice embryogenesis
Authors: Ito Momoyo , Sentoku Naoki , Nishimura Asuka , Hong Soon‐Kwan , Sato Yutaka , Matsuoka Makoto
Published: March 2003

In early plant embryogenesis, the determination of cell fate in the protodermal cell layer is considered to be the earliest event in radial pattern formation. To elucidate the mechanisms of epidermal cell fate determination and radial pattern formation in early rice embryogenesis, we have isolated a GL2‐type homeobox gene Roc1 (Rice outermost cell‐specific gene1), which is specifically expressed in the protoderm (epidermis). In early rice embryogenesis, cell division occurs randomly and the morphologically distinct layer structure of the protoderm cannot be observed until the embryo reaches more than 100 µm in length. Nonetheless, in situ hybridization analyses revealed that specific expression of Roc1 in the outermost cells is established shortly after fertilization, much earlier than protoderm differentiation. In the regeneration process from callus, the Roc1 gene is also expressed in the outermost cells of callus in advance of tissue and organ differentiation, and occurs independently of whether the cells will differentiate into epidermis in the future or not. Furthermore, this cell‐specific Roc1 expression could be induced flexibly in the newly produced outermost cells when we cut the callus. These findings suggest that the expression of Roc1 in the outermost cells may be dependent on the positional information of cells in the embryo or callus prior to the cell fate determination of the protoderm (epidermis). Furthermore, the Roc1 expression is downregulated in the inner cells of ligule, which have previously been determined as protodermal cells, also suggesting that the Roc1 expression is position dependent and that this position dependent Roc1 expression is important also in post‐embryonic protoderm (epidermis) differentiation.
A novel, two‐component system for cell lethality and its use in engineering nuclear male‐sterility in plants
Authors: Burgess Diane G. , Ralston Edward J. , Hanson William G. , Heckert Matthew , Ho Minh , Jenq Tina , Palys Joseph M. , Tang Keliang , Gutterson Neal
Published: March 2003

Ablation of cells by the controlled expression of a lethal gene can be used to engineer plant traits such as male sterility and disease resistance. However, it may not be possible to achieve sufficient specificity of expression to prevent secondary effects in non‐targeted tissues. In this paper we demonstrate that the extracellular ribonuclease, barnase, can be engineered into two complementary fragments, allowing overlapping promoter specificity to be used to enhance targeting specificity. Using a transient system, we first show that barnase can be split into two inactive peptide fragments, that when co‐expressed can complement each other to reconstitute barnase activity. When a luciferase reporter gene was introduced into plant cells along with genes encoding both partial barnase peptides, a substantial reduction in luciferase activity was seen. Cytotoxicity of the reconstituted barnase was demonstrated by crossing together parents constitutively expressing each of the barnase fragments, then assaying their progeny for the presence of both partial barnase genes. None of over 300 tomato seeds planted resulted in a viable progeny that inherited both transgenes. When expression of the partial barnase genes was instead targeted to the tapetum, male sterility resulted. All 13 tomato progeny that inherited both transgenes were male sterile, whereas the three progeny inheriting only the N‐terminal barnase gene were male fertile. Finally, we describe how male sterility generated by this type of two‐component system can be used in hybrid seed production.
Cloning and functional characterisation of an enzyme involved in the elongation of Δ6‐polyunsaturated fatty acids from the moss Physcomitrella patens
Authors: Zank Thorsten K. , Zähringer Ulrich , Beckmann Christoph , Pohnert Georg , Boland Wilhelm , Holtorf Hauke , Reski Ralf , Lerchl Jens , Heinz Ernst
Published: March 2003

The moss Physcomitrella patens contains high proportions of polyunsaturated very‐long‐chain fatty acids with up to 20 carbon atoms. Starting from preformed C18 polyunsaturated fatty acids, their biosynthesis involves a sequence of Δ6‐desaturation, Δ6‐elongation and Δ5‐desaturation. In this report we describe for the first time the characterisation of a cDNA (PSE1) of plant origin with homology to the ELO‐genes from Saccharomyces cerevisiae, encoding a component of the Δ6‐elongase. Functional expression of PSE1 in S. cerevisiae led to the elongation of exogenously supplied Δ6‐polyunsaturated fatty acids. By feeding experiments with different trienoic fatty acids of natural and synthetic origin, both substrate specificity and substrate selectivity of the enzyme were investigated. The activity of Pse1, when expressed in yeast, was not sensitive to the antibiotic cerulenin, which is an effective inhibitor of fatty acid synthesis and elongation. Furthermore, the PSE1 gene was disrupted in the moss by homologous recombination. This led to a complete loss of all C20 polyunsaturated fatty acids providing additional evidence for the function of the cDNA as coding for a component of the Δ6‐elongase. The elimination of the elongase was not accompanied by a visible alteration in the phenotype, indicating that C20‐PUFAs are not essential for viability of the moss under phytotron conditions.
The absence of molybdenum cofactor sulfuration is the primary cause of the flacca phenotype in tomato plants
Authors: Sagi Moshe , Scazzocchio Claudio , Fluhr Robert
Published: March 2003

The molybdenum cofactor (MoCo)‐containing enzymes aldehyde oxidase (AO; EC 1.2.3.1) and xanthine dehydrogenase (XDH; EC 1.2.1.37) require for activity a sulfuration step that inserts a terminal sulfur ligand into the MoCo. The tomato flacca mutation was originally isolated as a wilty phenotype due to a lack of abscisic acid (ABA) that is related to simultaneous loss of AO and XDH activities. An expressed sequence tag candidate from tomato was selected on the basis of homology to sulfurases from animals, fungi and the recently isolated Arabidopsis genes LOS5/ABA3. The tomato homologue maps as a single gene to the bottom of chromosome 7, consistent with the genetic location of the flacca mutation. The structure of FLACCA shows a multidomain protein with an N‐terminal NifS‐like sulfurase domain; a mammal‐specific intermediate section; and a C‐terminus containing conserved motifs. Prominent among these are molybdopterin oxidoreductases and thioredoxin redox‐active centre/iron–sulfur‐binding region signatures which may be relevant to the specific sulfuration of MoCo. Indeed, the molecular analysis of flacca identifies the mutation in a highly conserved motif located in the C‐terminus. Activity gel assays show that FLACCA is expressed throughout the plant. Transient and stable complementation of flacca and the Arabidopsis aba3 mutants with Aspergillus nidulans hxB and FLACCA yielded full, partial and tissue‐specific types of Mo‐hydroxylase activities. Restoration of activity in the root alone is sufficient to augment plant ABA content and rectify the wild‐type phenotype. Thus the pleiotropic flacca phenotype is due to the loss of activity of enzymes requiring a sulfurated MoCo.
Transgenic crops, biotechnology and ownership rights: what scientists need to know
Authors: Kowalski Stanley P. , Ebora Reynaldo V. , Kryder R. David , Potter Robert H.
Published: March 2003

Ownership of intellectual and tangible property (IP/TP) rights in agricultural biotechnology (ag‐biotech) and transgenic plants has become critically important. For scientists in all institutions, whether industrialized or developing country, public or private sector, an understanding of IP/TP rights is fundamental in both research and development. Transgenic plants and ag‐biotech products embody numerous components and processes, each of which may have IP/TP rights attached. To identify these rights, a transgenic plant or ag‐biotech product must be dissected into its essential components and processes, with each ‘piece’ analysed under the IP/TP ‘microscope’. This product deconstruction is an integral step in product clearance (PC) analysis leading to freedom to operate (FTO). To facilitate a PC analysis, the following points are important: (1) knowing what one has and where it's from, (2) organizing material transfer agreements and licences, (3) researching scientific and patent databases and relevant literature, (4) instituting a laboratory notebook policy, (5) keeping track of ownership of germplasm and plant genetic resources, and (6) promoting ongoing IP/TP management, awareness and training. However, a FTO opinion does not solve the IP/TP issues of releasing a transgenic plant or ag‐biotech product; rather, it is a management tool for assessing the risks of litigation. When transferring transgenic plants or ag‐biotech to developing nations, scientists from industrialized countries have the heightened responsibility of verifying that IP/TP issues are fully addressed and documented. Successful technology transfer goes beyond research, development and licensing; it is an holistic package leading to long‐term partnerships in international development. Managing IP/TP requires capacity‐building in scientists and technology transfer offices, in both industrialized and developing countries.
Key amino acid residues required for aryl migration catalysed by the cytochrome P450 2‐hydroxyisoflavanone synthase
Authors: Sawada Yuji , Kinoshita Kengo , Akashi Tomoyoshi , Aoki Toshio , Ayabe Shin‐ichi
Published: March 2003

Isoflavonoids are distributed predominantly in leguminous plants, and play pivotal roles in the interaction of host plants with biological environments. Isoflavones in the diet also have beneficial effects on human health as phytoestrogens. The isoflavonoid skeleton is constructed by the CYP93C subfamily of cytochrome P450s in plant cells. The reaction consists of hydroxylation of the flavanone molecule at C‐2 and an intramolecular 1,2‐aryl migration from C‐2 to C‐3 to yield 2‐hydroxyisoflavanone. In this study, with the aid of alignment of amino acid sequences of CYP93 family P450s and a computer‐generated putative stereo structure of the protein, candidates for key amino acid residues in CYP93C2 responsible for the unique aryl migration in 2‐hydroxyisoflavanone synthase reaction were identified. Microsomes of recombinant yeast cells expressing mutant proteins of CYP93C2 were prepared, and their catalytic activities tested. The reaction with the mutant in which Ser 310 in the centre of the I‐helix was converted to Thr yielded increased formation of 3‐hydroxyflavanone, a by‐product of the 2‐hydroxyisoflavanone synthase reaction, in addition to the major isoflavonoid product. More dramatically, the mutant in which Lys 375 in the end of β‐sheet 1–4 was replaced with Thr produced only 3‐hydroxyflavanone and did not yield the isoflavonoid any longer. The roles of these amino acid residues in the catalysis and evolution of isoflavonoid biosynthesis are discussed.
Rapid identification of Arabidopsis insertion mutants by non‐radioactive detection of T‐DNA tagged genes
Authors: Ríos Gabino , Lossow Andrea , Hertel Britta , Breuer Frank , Schaefer Sabine , Broich Melanie , Kleinow Tatjana , Jásik Ján , Winter Jochen , Ferrando Alejandro , Farrás Rosa , Panicot Mireia , Henriques Rossana , Mariaux Jean‐Baptist , Oberschall Attila , Molnár Gergely , Berendzen Kenneth , Shukla Vijaya , Lafos Marcel , Koncz Zsuzsanna , Rédei George P. , Schell Jeff , Koncz Csaba
Published: March 2003

To assist in the analysis of plant gene functions we have generated a new Arabidopsis insertion mutant collection of 90 000 lines that carry the T‐DNA of Agrobacterium gene fusion vector pPCV6NFHyg. Segregation analysis indicates that the average frequency of insertion sites is 1.29 per line, predicting about 116 100 independent tagged loci in the collection. The average T‐DNA copy number estimated by Southern DNA hybridization is 2.4, as over 50% of the insertion loci contain tandem T‐DNA copies. The collection is pooled in two arrays providing 40 PCR templates, each containing DNA from either 4000 or 5000 individual plants. A rapid and sensitive PCR technique using high‐quality template DNA accelerates the identification of T‐DNA tagged genes without DNA hybridization. The PCR screening is performed by agarose gel electrophoresis followed by isolation and direct sequencing of DNA fragments of amplified T‐DNA insert junctions. To estimate the mutation recovery rate, 39 700 lines have been screened for T‐DNA tags in 154 genes yielding 87 confirmed mutations in 73 target genes. Screening the whole collection with both T‐DNA border primers requires 170 PCR reactions that are expected to detect a mutation in a gene with at least twofold redundancy and an estimated probability of 77%. Using this technique, an M2 family segregating a characterized gene mutation can be identified within 4 weeks.
Silica deposition by a strongly cationic proline‐rich protein from systemically resistant cucumber plants
Authors: Kauss Heinrich , Seehaus Kai , Franke Rochus , Gilbert Sabine , Dietrich Robert A. , Kröger Nils
Published: March 2003

Infection of one leaf of cucumber (Cucumis sativa) plants can render other leaves resistant to various pathogens. This so‐called systemic acquired resistance (SAR) can be functionally mimicked by certain chemicals. All these treatments enhanced expression of a gene encoding a novel proline‐rich protein (PRP1) which has C‐terminal repetitive sequences containing an unusually high amount of lysine and arginine residues. Antibodies raised against a synthetic peptide derived from four of the repetitive sequences cross‐reacted mainly with a cell wall polypeptide of an apparent MW of 8 kDa. The protein accumulated upon SAR induction, though it does not appear to take part in oxidative protein cross‐linking, at least in the hypocotyl tissue. The synthetic peptide derived from the repetitive sequences was able to polymerize orthosilicic acid to insoluble silica, a property not resulting directly from the primary protein sequence, but rather from the high positive charge density. Our results suggest that during induction of SAR, the synthesis of a strongly cationic PRP prepares the cell walls for enhanced silica deposition which is known to participate in cell wall reinforcement, localized at the site of attempted penetration of fungi into epidermal cells. Constitutive accumulation of related PRPs may function in silica deposition during certain developmental stages, a process important for various physiological functions of green plants.
Proliferating Floral Organs (Pfo), a Lotus japonicus gene required for specifying floral meristem determinacy and organ identity, encodes an F‐box protein
Authors: Zhang Shulu , Sandal Niels , Polowick Patricia L. , Stiller Jiri , Stougaard Jens , Fobert Pierre R.
Published: March 2003

To study flower development in the model legume Lotus japonicus, a population of transgenic plants containing a maize transposable element (Ac) in their genome was screened for floral mutants. One mutation named proliferating floral organs (pfo) causes plants to produce a large number of sepal‐like organs instead of normal flowers. It segregates as a single recessive Mendelian locus, and causes sterility. Scanning electron microscopy revealed that pfo affects the identity, number and arrangement of floral organs. Sepal‐like organs form in the first whorl, and secondary floral meristems are produced in the next whorl. These in turn produce sepal‐like organs in the first whorl and floral meristems in the second whorl, and the process is reiterated. Petals and stamens are absent while carpels are either absent or reduced. The pfo phenotype was correlated with the presence of an Ac insertion yielding a 1.6‐kb HindIII restriction fragment on Southern blots. Both the mutant phenotype and this Ac element are unstable. Using the transposon as a tag, the Pfo gene was isolated. Conceptual translation of Pfo predicts a protein containing an F‐box, with high overall similarity to the Antirrhinum FIMBRIATA, Arabidopsis UNUSUAL FLORAL ORGANS and Pisum sativum Stamina pistilloida proteins. This suggests that Pfo may regulate floral organ identity and meristem determinacy by targeting proteins for ubiquitination.
Clinical use of FFP: results of a retrospective process and outcome audit
Authors: Jones  , Jones  , Napier  , Al‐Ismail
Published: March 2003

An audit has been carried out on the usage of 216 units of fresh frozen plasma (FFP) issued to 41 patients. This involved the systems of FFP issue, the appropriateness of prescription as well as the recorded benefits. Sixty‐six per cent of the initial requests for FFP appeared to satisfy criteria for appropriate use. Review of the case notes resulted in some changes to earlier decisions and a slight increase to 73% of those accepted as valid. Only 94% of the FFP issued could be proved to have been given to identified patients and only 88% of case notes showed the reason for treatment.

Pre‐ and post‐treatment coagulation results were available for all patients. In 15% of cases, pretreatment results were not significantly abnormal, and consequently no post‐treatment improvement found. Coagulation improvement was documented in 78% of cases, and clinical statements on patient progress noted in 40%.

In 80% of cases, the patient received other blood products carrying a potential virus risk. Six of the remaining eight patients were treated to stabilize oral anticoagulation. For these patients, virus‐inactivated prothrombin concentrates could have been used, resulting in almost the same reduction in virus transmission risk for the group of 41 patients as could be obtained by using virus‐inactivated FFP.
A survey of blood utilization in children and adolescents in a German university hospital
Authors: Zimmermann  , Handtrack  , Zingsem  , Weisbach  , Neidhardt  , Glaser  , Eckstein
Published: March 2003

There are no detailed data on blood use with regard to diagnoses of recipients during infancy, childhood and adolescence. Available information on this issue is incomplete and no longer current. We conducted a survey of blood component use in children and adolescents in an acute‐care university hospital in the greater area of Nuremberg between June 1994 and September 1996. Packed red blood cells (RBCs), fresh‐frozen plasmas (FFPs) and platelet (PLT) components were evaluated for the recipients discharge diagnoses. Source study files were extracted from the hospital transfusion service and the medical records department. Transfused units were listed by broad diagnostic categories and leading diagnostic groups formed from principal diagnoses of the recipients according to the International Classification of Diseases, 9th edn (ICD‐9). 34.3% of 2869 RBC cell units, 35.0% of 1095 FFP units and 5.0% of 1028 PLT components were used in patients with congenital diseases, mainly cardiac defects. The disease category neoplastic diseases was next most frequently associated with blood transfusion diagnosed in recipients of 23.9% of all RBCs, 15.6% of all FFP units and in 66.4% of all PLT units. Malignant diseases and benign haematological diseases (diagnostic categories II and IV) accounted for 68.9% of all costs of blood component transfusion. These findings demonstrate the increased importance of platelet transfusion for the organization of local and regional blood donation programmes and for cost analysis exercises. The study shows that detailed information on local blood use may be obtained quickly using available data collections of transfusion services and medical record departments.
Platelet‐specific antibodies in female blood donors after pregnancy
Authors: Schnaidt  , Wernet
Published: March 2003

Sera of 500 female blood donors after pregnancy were tested for platelet‐specific antibodies (HPA‐1, 3, 5) using the MAIPA assay. Twenty‐one sera (4.2%) were found to be positive: four anti‐HPA‐1a, one anti‐HPA‐5a and 16 anti‐HPA‐5b. Sera were positive up to 30 years after the last pregnancy. All women with antibodies were HLA‐DR52 positive and 79% of the women with anti‐HPA‐5b were HLA‐DR6 positive.
Unchanging attitudes to autologous transfusion in the UK
Authors: Torella F. , Haynes S. L. , Lardi A. , O'Dwyer S. T. , McCollum C. N.
Published: March 2003

. Our aim was to assess changes in attitudes to autologous transfusion amongst surgeons over a 10‐year period in response to scientific evidence, public awareness, published guidelines, management and the increasing cost of blood products.

Surgeons across the north‐west of England completed questionnaires on knowledge, experience and attitude towards autologous transfusion in 1990, 1994 and 1999.

Main outcome measures were changes in knowledge, experience and utilization of autologous transfusion; perceived advantages of autologous transfusion, obstacles to its implementation in surgical practice and preferences for specific techniques (preoperative autologous donation, acute normovolaemic haemodilution, intraoperative and postoperative cell salvage).

There has been little change in practice over 10 years. Many more surgeons were keen to employ autologous transfusion than were using it. Autologous transfusion was only used in general, orthopaedic and cardiothoracic surgery. Safety and patient preference were the main arguments for implementation and logistics the main obstacles.

Autologous transfusion was used sporadically in surgical practice. Clinical trials are needed to guide clinicians in the choice of transfusion techniques.
Natural and recombinant A and B gene encoded glycosyltransferases
Authors: Palcic M. M. , Seto N. O. L. , Hindsgaul O.
Published: March 2003

. The human blood group A and B synthesizing enzymes are glycosyltransferases that catalyse the transfer of a monosaccharide residue from UDP‐GalNAc and UDP‐Gal donors, respectively, to αFuc1,2‐Gal terminated blood group H acceptors. Extensive investigations of their substrate specificity and physical properties have been carried out since their initial discovery. These studies demonstrated a rigid specificity for the acceptor structure, crossover in donor specificity and immunological similarity along with chromatographic differences. Cloning of the enzymes has shown that they are highly homologous, differing in only four of their 354 amino acids. Changing the residues Arg176→Gly, Gly235→Ser, Leu266→Met and Gly 268→Ala converts the enzyme specificity from blood group A to blood group B glycosyltransferase. Structure function investigations have been carried out by systematic interchange and modification of these four critical amino acids. These studies have shown that donor specificity is attributed to the last two amino acids. Mutants have also been produced with greatly enhanced turnover rates as well as hybrid A/B enzymes that catalyse both reactions efficiently.
Polymorphism and recombination events at theABOlocus: a major challenge for genomic ABO blood grouping strategies
Authors: Olsson M. L. , Chester M. A.
Published: March 2003

. The blood groupABOgene codes for a glycosyltransferase that adds the ultimate monosaccharide to a glycoconjugate and forms the A or B blood group specific antigen. The DNA structure of the three major alleles of the human blood group ABO system was first described in 1990. This review describes the subsequent developments, including the increasing number of variants of these common alleles and the underlying mutations thought to be responsible for the occurrence of some of the weak subgroups of blood group A and B. Several inactive (O) alleles are also now known. Our knowledge of the DNA sequence of the normalAandBalleles and of the rare and intriguingcisAB and B(A) phenotypes has resulted in plausible explanations for these.

Allelic variations outside the translated exons have been investigated and resulted in detection of lineage‐specific intron mutations and the discovery of an enhancer VNTR region affecting the rate of transcription at this locus.

The occurrence of hybrid alleles can also explain hitherto abnormal inheritance in some pedigrees. The detection of hybrid alleles has been made possible by the presence of numerous polymorphisms found in the variousABOalleles. The role ofchi(χ) sequences is discussed.

Finally, the various genotyping methods available are summarized and their advantages and limitations are analysed in the light of the increasing allelic variation.
Outcome of consecutive pregnancies in a patient with Bombay (Oh) blood group
Authors: Bhattacharya S. , Makar Y. , Laycock R. A. , Gooch A. , Poole J. , Hadley A.
Published: March 2003

Summary A young lady with a rare Bombay (Oh) blood group had two successive uneventful pregnancies. Her serum contained a potent high‐titre anti‐H and serological as well as chemiluminescence tests, suggesting that the antibody was haemolytic. Her husband was of the normal H status. Theoretically, both babies should have been positive for the H antigen and should have suffered from haemolytic disease of the newborn.

This apparent conundrum could be owing to the weak expression of the H antigens on the infant red cells.
Enhancement of the antimalarial effect of chloroquine by chloropheniramine in vivo
Authors: Sowunmi  , Oduola  , Ogundahunsi  , Salako
Published: March 2003

SummaryThe efficacy of chloroquine and chloroquine plus chloropheniramine, a histamine H1 receptor blocker which reverses chloroquine insensitivity in Plasmodium falciparum in vitro, was studied in 96 children with acute symptomatic uncomplicated falciparum malaria. The chloroquine/chloropheniramine combination produced a significantly higher cure rate than chloroquine alone and cured 77% of children with chloroquine treatment failures. Children with chloroquine treatment failure had mean plasma chloroquine concentrations above the minimum therapeutic concentration for the area. Chloroquine concentrations in plasma and red blood cells and ratio of red cell to plasma chloroquine concentrations on days 3 and 7 after initiation of therapy were not significantly different in the two groups. Chloroquine/chloropheniramine produces a higher cure rate than chloroquine alone and reverses chloroquine insensitivity in Plasmodium falciparum in vivo. It may be a useful way of optimising the antimalarial effect of chloroquine.
Schiotz tonometry for glaucoma: are there simple alternatives?
Authors: Kok  , Berendschot  , Hardus
Published: March 2003

SummaryIn the period from October 1991 until August 1992, 864 eye‐patients in a rural area in south‐east Nigeria were examined in order to find simple parameters for the screening of glaucoma simplex. Schiotz tonometry was used as the gold standard. Investigation of the pupil‐reaction with a torch, estimation of the pressure of the (closed) eye by digital palpation, and estimations of the cup/disc ratio by ophthalmoscopy can be used as an alternative.
The effect of chemoprophylaxis on the timing of onset of falciparum malaria
Authors: Reyburn Hugh , Behrens Ron H. , Warhurst David , Bradley David
Published: March 2003

The association between chemoprophylaxis and delayed onset of falciparum malaria was investigated in a retrospective study of 477 nonimmune cases reported to the UK Malaria Reference Laboratory (MRL) who had used either mefloquine (n = 56), chloroquine‐proguanil (n = 90) or no chemoprophylaxis (n = 331). For holiday and short‐term travellers using mefloquine the time between arrival in the UK and diagnosis was found to be significantly longer than for chloroquine and proguanil (C‐P) users or for those who had not used prophylaxis at all (P < 0.004). This delay was primarily due to a later onset of symptoms. C‐P use was not associated with delay in onset of symptoms or diagnosis when compared to not using prophylaxis. Possible reasons for the findings are discussed. Mefloquine may continue to exert a partially suppressive effect on resistant strains of Plasmodium falciparum (Pf). That chloroquine with proguanil was not found to have such an effect may be due to poor compliance to proguanil or differences in the mode of action and range of parasite resistance to the two regimens. Differences in drug compliance may be one reason why only mefloquine users on holiday or short‐term journeys experienced delays to onset of disease. Drug compliance amongst cases of breakthrough malaria on chemoprophylaxis may be lower than is generally recognized. It is important for clinicians and travellers to be aware that the onset of falciparum malaria may be delayed by mefloquine prophylaxis.
Susceptibility of severe combined immuno‐deficient (SCID) mice to Trypanosoma brucei gambiense and T. b. rhodesiense
Authors: Inoue  , Narumi  , Mbati  , Hirumi  , Situakibanza  , Hirumi
Published: March 2003

Susceptibility of severe combined immunodeficient (SCID) mice to 7 isolates of Trypanosoma brucei gambiense and 2 isolates of T. b. rhodesiense was examined in terms of their infectivity, course of parasitaemia, packed cell volume (PCV) and survival period in comparison with that of normal immunocompetent (BALB/c) mice. All isolates of T. b. gambiense and T. b. rhodesiense caused high (> 1 × 108 parasites/ml) parasitaemia in the SCID mice, the survival periods ranged from 5 to 47 days. On the other hand, 5 of 7 isolates of T. b. gambiense developed chronic infection in the BALB/c mice with sporadic but persistent parasitaemia with less than 5 × 106 parasites/ml. All the mice tested in this group survived more than 60 days after infection. In contrast, the 2 remaining isolates of T. b. gambiense and both isolates of T. b. rhodesiense showed high virulence in the BALB/c mice and killed all of them within 30 days after infection. The results demonstrate that the SCID mice, in which functional B‐ and T‐cell‐mediated immunities are congenitally lacking, are highly susceptible for ‘low‐virulence’T. b. gambiense. This makes SCID mice useful tools for the isolation of parasites from T. b. gambiense sleeping sickness patients and the propagation of large amounts of such parasites.
The potential role of peripheral health workers and community key informants in the rapid assessment of community burden of disease: the example of lymphatic filariasis
Authors: Gyapong John O. , Gyapong John O. , Webber Roger H. , Bennett Steve
Published: March 2003

Data for planning disease control programs in most developing countries is often not available because they are usually expensive to gather. This study explored the potential use of peripheral health staff and community key informants in gathering community‐level data about lymphatic filariasis. Agreement between findings of health workers and those of physicians was very high (κ 0.66–0.87) for the clinical conditions examined. The prevalence of hydrocele was found to be a good predictor of communities at risk of filariasis. Community key informants provided very useful qualitative and quantitative data on the prevalence of clinical filariasis. The need to use nontraditional health professionals in gathering data for planing control programs is discussed.
Trichomoniasis treatment in women: a systematic review
Authors: Gülmezoglu A. Metin , Garner Paul
Published: March 2003

objective To compare the effectiveness of various treatment strategies for trichomoniasis in women.

data sources Medline from 1966 to1996, Embase from 1986 to 1996, Science Citation Index from 1990 to 1996; reference lists of existing reviews; through the manufacturers of metronidazole and tinidazole in the UK, the Cochrane Controlled Trials Register until October 1997 and informal discovery.

study selection Any randomized or quasi‐randomized trial in nonpregnant women with trichomoniasis where different treatment strategies were compared. 45 of the 124 identified studies met the criteria and were included in the review.

data extraction Settings, diagnostic methods, exclusions, loss to follow‐up and partner treatment strategies were extracted. Outcomes sought were parasitological cure, clinical cure and side‐effects of treatment.

results Most trials were small, with only two trials containing more than 100 women in each comparison group. Only 11 trials followed up women for more than one month. Oral nitroimidazoles were effective in achieving parasitological cure. Fourteen trials compared different treatment strategies with the remainder comparing different doses or different drugs. Partner treatment was effective in decreasing longer‐term re‐infection rates in the one trial testing this.

conclusions Parasitological cure can be achieved by a single oral dose of nitroimidazoles. There is, however, very little data on partner treatment strategies and long‐term cure rates after initial treatment. Further research should test various partner treatment strategies to prevent re‐infections and reduce trichomoniasis prevalence.
Characterization of secretory acetylcholinesterase from Setaria cervi microfilariae: a potential antigen for diagnosis of human filariasis
Authors: Sharma Sudha , Rathaur Sushma
Published: March 2003

Summary Acetylcholinesterase (AChE) is released to the external medium when microfilariae (mf) of Setaria cervi, a bovine filarial parasite, are maintained in vitro. Intense enzyme staining at amphids, excretory pores, anal vesicle and phasmids suggest an active secretion of AChE from mf. Excretory‐secretory products of mf displayed two electromorphic variants of AChE when resolved by 6% nondenaturing PAGE. The two isoforms of AChE (A and B) were separated on the basis of charge by DEAE sepharose CL 6B column following gel filtration. The two isoforms showed differing kinetic properties with respect to substrate specificity and inhibitor sensitivity. Anti‐Nippostrongylus brasiliensis AChE antibodies cross‐reacted with the affinity purified secretory AChE in ELISA. Immunoblotting of purified AChEs with cross‐reacting anti‐AChE antibodies revealed the presence of an approximately 75 kD protein in the isoenzyme A and an approximately 45 kD protein in B, whereas both proteins were present in the enzyme purified via affinity chromatography on edrophonium sepharose column.
Parameters associated with Schistosoma haematobium infection before and after chemotherapy in school children from two villages in the Coast province of Kenya
Authors: Kahama Anthony I. , Vennervald Birgitte J. , Kombe Yeri , Kihara Ruth W. , Ndzovu Malick , Mungai Peter , Ouma John H.
Published: March 2003

Summary We evaluated the impact of praziquantel therapy (40 mg/kg body weight) on indicators of infection with Schistosoma haematobium by following a cohort of infected children from schools located 12 km apart in the Coast province of Kenya, at 0, 2, 4, 6, 12 and 18 months after treatment. Within this period, measurements of infection parameters pertaining to egg counts and haematuria (micro‐, macro‐ and history) were evaluated at all time points. The initial prevalence of 100% dropped significantly 8 weeks after treatment with a similar trend in the intensity of infection. Microhaematuria followed the same trend as observed for egg counts while macrohaematuria remained low after treatment. Reinfection following successful therapy differed significantly between schools; in one school the children were reinfected immediately while those in the other remained uninfected despite similar starting prevalences, intensities of infection and cure rates. Transmission between the two areas looked homogeneous before treatment but when both groups were treated, contrasting transmission patterns became evident. In a regression model we evaluated factors that might be associated with reinfection, and after allowing for pretreatment infection level, age and sex, area (school) remained a highly significant predictor.