bluuebunny/crossref_metadata_2025_split huggingface dataset:
A peptide methionine sulfoxide reductase highly expressed in photosynthetic tissue in Arabidopsis thaliana can protect the chaperone‐like activity of a chloroplast‐localized small heat shock protein
Authors: Gustavsson Niklas , Kokke Bas PA. , Härndahl Ulrika , Silow Maria , Bechtold Ulrike , Poghosyan Zaruhi , Murphy Denis , Boelens Wilbert C. , Sundby Cecilia 
Published: March 2003

SummaryThe oxidation of methionine residues in proteins to methionine sulfoxides occurs frequently and protein repair by reduction of the methionine sulfoxides is mediated by an enzyme, peptide methionine sulfoxide reductase (PMSR, EC 1.8.4.6), universally present in the genomes of all so far sequenced organisms. Recently, five PMSR‐like genes were identified in Arabidopsis thaliana, including one plastidic isoform, chloroplast localised plastidial peptide methionine sulfoxide reductase (pPMSR) that was chloroplast‐localized and highly expressed in actively photosynthesizing tissue (Sadanandom A et al., 2000). However, no endogenous substrate to the pPMSR was identified. Here we report that a set of highly conserved methionine residues in Hsp21, a chloroplast‐localized small heat shock protein, can become sulfoxidized and thereafter reduced back to methionines by this pPMSR. The pPMSR activity was evaluated using recombinantly expressed pPMSR and Hsp21 from Arabidopsis thaliana and a direct detection of methionine sulfoxides in Hsp21 by mass spectrometry. The pPMSR‐catalyzed reduction of Hsp21 methionine sulfoxides occurred on a minute time‐scale, was ultimately DTT‐dependent and led to recovery of Hsp21 conformation and chaperone‐like activity, both of which are lost upon methionine sulfoxidation (Härndahl et al., 2001). These data indicate that one important function of pPMSR may be to prevent inactivation of Hsp21 by methionine sulfoxidation, since small heat shock proteins are crucial for cellular resistance to oxidative stress.
An EDS1 orthologue is required for N‐mediated resistance against tobacco mosaic virus
Authors: Peart Jack R. , Cook Graeme , Feys Bart J. , Parker Jane E. , Baulcombe David C. 
Published: March 2003

SummaryIn Arabidopsis, EDS1 is essential for disease resistance conferred by a structural subset of resistance (R) proteins containing a nucleotide‐binding site, leucine‐rich‐repeats and amino‐terminal similarity to animal Toll and Interleukin‐1 (so‐called TIR‐NBS‐LRR proteins). EDS1 is not required by NBS‐LRR proteins that possess an amino‐terminal coiled‐coil motif (CC‐NBS‐LRR proteins). Using virus‐induced gene silencing (VIGS) of a Nicotiana benthaminana EDS1 orthologue, we investigated the role of EDS1 in resistance specified by structurally distinct R genes in transgenic N. benthamiana. Resistance against tobacco mosaic virus mediated by tobacco N, a TIR‐NBS‐LRR protein, was EDS1‐dependent. Two other R proteins, Pto (a protein kinase), and Rx (a CC‐NBS‐LRR protein) recognizing, respectively, a bacterial and viral pathogen did not require EDS1. These data, together with the finding that expression of N. benthamiana and Arabidopsis EDS1 mRNAs are similarly regulated, lead us to conclude that recruitment of EDS1 by TIR‐NBS‐LRR proteins is evolutionarily conserved between dicotyledenous plant species in resistance against bacterial, oomycete and viral pathogens. We further demonstrate that VIGS is a useful approach to dissect resistance signaling pathways in a genetically intractable plant species.
The role of invertases and hexose transporters in controlling sugar ratios in maternal and filial tissues of barley caryopses during early development
Authors: Weschke Winfriede , Panitz Reinhard , Gubatz Sabine , Wang Qing , Radchuk Ruslana , Weber Hans , Wobus Ulrich 
Published: March 2003

SummaryTo analyse carbohydrate metabolism and its role during early seed development of barley we characterised genes encoding two cell wall‐bound invertases (HvCWINV1 and HvCWINV2) and two putative hexose transporter‐like genes (HvSTP1 and HvSTP2). No typical vacuolar invertase gene could be identified. Instead, a gene encoding sucrose:fructan 6‐fructosyltransferase (HvSF6FT1), an enzyme with soluble acid invertase activity, was isolated and characterised. Furthermore, enzyme activities and sugar levels were measured. HvSF6FT1‐mRNA levels and acid soluble invertase activity are highest in the maternal pericarp 1–2 days after flowering (DAF). HvSF6FT1 is strongly expressed in regions flanking the main vascular bundle and to a lower extent in filial endospermal transfer cells, which persist until maturity and never accumulate starch. In contrast, cell wall‐bound invertase HvCWINV2 is expressed early in development mainly in the style region and later on in pericarp areas which transiently accumulate starch and undergo degradation later in development. The hexose transporter HvSTP2 shows a temporal and spatial expression pattern similar to HvCWINV2. Transcripts of HvCWINV1 have been localised within the first row of endospermal cells and in the outermost area of the nucellar projection as well as in endospermal transfer cells before starch filling; the same regions of the endosperm are labelled with a hexose transporter HvSTP1‐probe. HvSTP1 is expressed at very low levels within the pericarp but much higher in the syncytial endosperm at 3 DAF and in endospermal transfer cells 7 DAF. The temporal and spatial association of HvCWINV1 and HvSTP1 expression indicates that hexoses liberated by the invertase within the endospermal cavity are taken up by the transporter to be delivered into the central uncellularised space of the endosperm to supply mitotically active endosperm cells with hexoses. The results are discussed and compared with published data on the role of soluble sugars as signal molecules in seed developmental processes.
A novel ER‐derived compartment, the ER body, selectively accumulates a β‐glucosidase with an ER‐retention signal in Arabidopsis
Authors: Matsushima Ryo , Kondo Maki , Nishimura Mikio , Hara‐Nishimura Ikuko 
Published: March 2003

SummaryThe ER body is a novel compartment that is derived from endoplasmic reticulum (ER) in Arabidopsis. In contrast to whole seedlings which have a wide distribution of the ER bodies, rosette leaves have no ER bodies. Recently, we reported that wound stress induces the formation of many ER bodies in rosette leaves, suggesting that the ER body plays a role in the defense system of plants. ER bodies were visualized in transgenic plants (GFP‐h) expressing green fluorescent protein (GFP) with an ER‐retention signal, HDEL. These were concentrated in a 1000‐g pellet (P1) of GFP‐h plants. We isolated an Arabidopsis mutant, nai1, in which fluorescent ER bodies were hardly detected in whole plants. We found that a 65‐kDa protein was specifically accumulated in the P1 fraction of GFP‐h plants, but not in the P1 fraction of nai1 plants. N‐terminal peptide sequencing revealed that the 65‐kDa protein was a β‐glucosidase, PYK10, with an ER‐retention signal, KDEL. Immunocytochemistry showed that PYK10 was localized in the ER bodies. Compared with the accumulation of GFP‐HDEL, which was associated with both cisternal ER and ER bodies, the accumulation of PYK10 was much more specific to ER bodies. PYK10 was one of the major proteins in cotyledons, hypocotyls and roots of Arabidopsis seedlings, while PYK10 was not detected in rosette leaves that have no ER bodies. These findings indicated that PYK10 is the main component of ER bodies. It is possible that PYK10 produces defense compounds when plants are damaged by insects or wounding.
An Arabidopsis mutant defective in UV‐B light‐mediated responses
Authors: Suesslin Christina , Frohnmeyer Hanns 
Published: March 2003

SummaryIn plants, low fluences of ultraviolet‐B radiation (UV‐B; 280–320 nm) trigger the activation of protection mechanisms and various photomorphogenic responses. We established a novel screen to isolate Arabidopsis T‐DNA mutants (uli, UV‐B light insensitive) with reduced sensitivity towards UV‐B light‐mediated inhibition of hypocotyl growth. One of the mutants, uli3, shows also a reduced sensitivity of UV‐B‐induced gene expression events and was, therefore, chosen for further investigation. The ULI3 gene encodes an 80‐kDa protein with potential domains for heme‐ and diacylglycerol‐binding. In transiently transfected protoplasts, the ULI3:GFP fusion protein is localised in the cytoplasm but also adjacent to membranes. In etiolated Arabidopsis seedlings irradiated by UV‐B, ULI3 mRNA expression is strongly up‐regulated. This is caused by elevated transcription as demonstrated using stable transformants where a GUS‐reporter was driven by the ULI3‐promoter. ULI3 is preferentially expressed in the outer cell layers in leaves, stems and flowers, but not in roots. There is evidence that ULI3 represents a specific component involved in UV‐B‐mediated signal transduction in higher plants.
A genome‐wide identification of E2F‐regulated genes in Arabidopsis
Authors: Ramirez‐Parra Elena , Fründt Corinne , Gutierrez Crisanto 
Published: March 2003

SummaryThe completion of the Arabidopsis genomic sequence offers the possibility to extract global information about regulatory mechanisms. Here, we describe a data mining strategy in combination with gene expression analysis to identify bona fide genes regulated by the E2F transcription factor. Starting with a genome‐wide search of chromosomal sites containing E2F‐binding sites, we studied in depth two of the most abundant E2F‐binding sites within the Arabidopsis genome and identified over 180 potential E2F target genes. Among them and in addition to cell cycle‐related genes, we have also identified genes belonging to other functional categories, e.g. transcription, stress and defense or signaling. We have determined the expression levels of genes selected from different categories under two experimental situations. Using cultured cells partially synchronized with aphidicolin, we found that most potential E2F targets identified in silico show a cell cycle‐regulated expression pattern with a peak in early/mid S‐phase. In addition, we used Arabidopsis transgenic plants expressing a DP gene containing a truncated DNA‐binding domain, which likely has a dominant‐negative effect on AtE2Fa, b and c (also named AtE2F3, 1 and 2, respectively), which require DP for efficient DNA binding. Contrary to the up‐regulation observed in early/mid S‐phase‐cultured cells, the expression of a large number of potential E2F targets was decreased in the transgenic plants. Our results strongly support that the RBR/E2F pathway plays a crucial role in regulating the expression of the genes identified in this study.
Loss of non‐host resistance of Arabidopsis NahG to Pseudomonas syringae pv. phaseolicola is due to degradation products of salicylic acid
Authors: Van Wees Saskia C. M. , Glazebrook Jane 
Published: March 2003

SummaryIn plants carrying the NahG transgene, salicylate hydroxylase converts salicylic acid (SA) to catechol. Arabidopsis NahG plants are defective in non‐host resistance to Pseudomonas syringae pv. phaseolicola strain 3121 (Psp), suggesting that resistance requires SA signaling. However, several mutants with defects in SA signaling, including eds1, pad4, eds5, sid2, and npr1, remain resistant to Psp, demonstrating that susceptibility of NahG plants is not due to absence of SA. SA synthesis is blocked in sid2NahG double mutants, but resistance to Psp is retained. Therefore, it must be the degradative action of NAHG on SA that causes the loss of resistance of NahG to Psp. Treatment of plants with catechol compromised Psp resistance suggesting that the effect of NahG on resistance results from catechol production. Application of catalase to NahG or catechol‐treated wild‐type plants partially restored resistance to Psp, suggesting that the deleterious effect of catechol results from inappropriate production of hydrogen peroxide. These results indicate that conclusions about SA requirements based solely on phenotypes of NahG plants should be re‐evaluated.
Fatal Clostridium perfringens sepsis from a pooled platelet transfusion
Authors: McDonald  , Hartley  , Orchard  , Hughes  , Brett  , Hewitt  , Barbara  
Published: March 2003

A male patient with acute myeloid leukaemia received a pooled platelet preparation prepared by Opti‐pressTM system on the last day of its shelf life. The patient collapsed after two‐thirds of the contents had been transfused. Clostridium perfringens was isolated from the platelet bag within 18 h of the acute event. Metronidazole, gentamicin and Clostridium antiserum were then administered in addition to the broad spectrum antibiotics started previously. However, the patient died 4 days after the platelets were transfused. The cause of death was given as cardiovascular shock, entirely compatible with an overwhelming bacteraemic and septic episode. A coroner's verdict of accidental death due to transfusion of a contaminated unit of platelets was recorded.On subsequent investigation Cl. perfringens type A serotype PS68,PS80 (identical to that found in the platelet bag) was cultured from the venepuncture site of the arm of one of the donors who contributed towards the platelet pool. The donor had two young children and frequently changed nappies. Faecal contamination of the venepuncture site was the suspected source for the transmission of Cl. perfringens, an organism commonly found in the soil and intestinal tract of humans. This case dramatically highlights the consequences of transfusing a bacterially contaminated unit. It is vital that such incidents are investigated and reported so that the extent of transfusion‐associated bacterial transmission can be monitored and preventative measures taken if possible.
The expression of the NB1 antigen on myeloid precursors and neutrophils from children and umbilical cords
Authors: Stroncek  , Shankar  , Litz  , Clement  
Published: March 2003

The neutrophil‐specific antigen NB1 is expressed by neutrophils from 97% of healthy adults. However, membrane expression of this molecule is unique in that it is found on only a subpopulation of neutrophils present in NB1‐positive adults. We have investigated the ontogeny of NB1 antigen expression by haematopoietic progenitor cells to determine the stage and pattern of antigen expression during granulocytic cell differentiation. In addition, we examined whether the ontogeny and frequency of granulocytic cells expressing the NBl antigen might vary in subjects according to age.A monoclonal antibody (MoAb) specific for NB1 (1B5) and flow cytometry was used to assess the frequency and characteristics of the NB1‐positive cells found in umbilical cord blood (n = 11), children (n = 37), healthy adults (n = 46) and patients with chronic myelogenous leukaemia (n = 8). We also used flow cytometry to isolate NB1‐positive and NB1‐negative bone marrow and peripheral blood cells from various tissue sources. The separated subpopulations were then analysed by Wright stain and light microscopy.The size of the NB1‐positive neutrophil subpopulation in 46 healthy adults (56 ± 19%) was identical to that found for neutrophils from 36 children ranging in age from 8 months to 18 years (56 ± 11%). In contrast, expression of the NB1 antigen by the neutrophils present in umbilical cord blood (91 ± 3%, n = 11) was significantly greater than that in adults (P < 0.002) or children (P < 0.002).We also examined the size of the NB1‐positive subpopulation among neutrophils from eight patients with chronic myelogenous leukaemia (CML). The NB1‐positive subset in CML subjects (29.5 ± 22.4%) was significantly less that in healthy adults (P < 0.02) or children (P < 0.02).Marrow cells from eight adults were similarly separated and analysed. We found that 69 ± 17% of segmented and band forms of neutrophils, 70 ± 2% of metamyelocytes and 61 ± 23% of myelocytes were NB1‐positive. In fetal bone marrow, 86 ± 9% of the segmented and band forms, 82 ± 10% of the metamyelocytes and 3 ± 4% of myelocytes were NB1‐positive.In conclusion, neutrophil‐specific antigen NB1 is first expressed at the myelocyte stage of myeloid differentitation. In adult bone marrow, the percentages of myelocytes, metamyelocytes and segmented or band cells that expressed this antigen were similar and comparable in magnitude to the frequency of NB1‐positive neutrophils found in the circulation. Although the size of the NBl‐positive neutrophil subpopulation was the same in healthy adults and children, it was significantly increased in umbilical cord blood, and in fetal marrow cells.
IgG anti‐Jka/Jkb antibodies are unlikely to fix complement
Authors: Yates  , Howell  , Overfield  , Voak  , Downie  , Austin  
Published: March 2003

Antibodies in the Kidd blood group system show a great deal of serological variability, are notoriously elusive and hence evoke difficulties in detection. However, they have been regularly reported as causing severe immediate or delayed haemolytic transfusion reactions and this clinical potential has been largely attributed to their complement binding ability.In initial investigations on 43 anti‐Jka/Jkb sera with a range of titres of IgG antibody only a few seemed to fix complement, though following repeated tests on 20 of these sera a further five were shown to bind complement, making a total of 12 (27.9%) showing evidence of complement binding. Twenty‐three sera were unavailable for re‐testing. Subsequent tests revealed that only those sera which showed direct agglutination or were positive with an anti‐IgM reagent in an indirect antiglobulin test (IAT) fixed complement. Evaluations on the IgG fractions of six selected potent anti‐Jka sera failed to reveal any complement‐fixing ability although all the original sera bound complement avidly and contained variable amounts of IgM antibody, some at very low subagglutinating levels.These findings challenge past perceptions and give cause for reflection on the changing methodologies and strategies which could unduly compromise the detection of these potentially clinically damaging antibodies.
Quality and standardization in blood component preparation with an automated blood processing technique
Authors: Van Rhenen  , Vermeij  , De Voogt  , Bernes  , Payrat  
Published: March 2003

The use of automated blood processors in combination with bottom and top blood containers has been found to improve the standardization and quality of blood components. A study was performed to validate a new type of processor (Optipress® II) and compare its performance with a first generation processor (Optipress® I).Primary separation on the Optipress II was investigated on 570 mL (± 10%) of anticoagulated blood in a nonpaired study. In addition, the quality of the products in routine production was compared between the results of the Optipress I and Optipress II. The whole blood units were kept overnight at room temperature (20 ± 2 °C). Separation was performed under conditions to obtain 55 mL buffy coats with a 50% haematocrit (ht). Platelet concentrate preparation was investigated in a paired study and compared to the routine manual method using PAS II additive solution. Parameters studied were volume, red cell, white cell and platelet counts, ht, haemoglobin (hb, total and free).Primary separation was more efficient in the Optipress II because the platelet count was lower in the erythrocyte concentrates (P < 0.0001), platelets were lower in plasma (P < 0.0001) and platelet counts were higher in buffy coats (P < 0.0001). Buffy coat volume showed less variation (Optipress II VC = 4%, Optipress I VC = 7.4%). Secondary separation did not show differences between the Optipress II and manual method but was advantageous because of the automatic termination of the procedure.Further improvement of standardization in blood component preparation is possible with an automated blood processor, leading to improvement of the quality of blood products for patient care.
The computer crossmatch: a safe alternative to the serological crossmatch
Authors: Chapman J. F. , Milkins C. , Voak D. 
Published: March 2003

. The crossmatch has evolved from including a wide range of techniques through a test purely to eliminate ABO incompatibility (immediate spin) to computer crossmatching in which no serological testing is carried out and validation ensures the correct ABO/RhD type blood is issued. The crossmatch was always considered to be the most important feature of the compatibility test and in particular the antiglobulin phase; however, there are potential risks associated with serological and computer crossmatching including technical and procedural errors. The use of immediate spin and computer crossmatch change the emphasis for safety of the compatibility test from the crossmatch to the antibody screen. UK guidelines have now been published describing the features necessary for the introduction of computer crossmatching. Computer crossmatching is used by many institutions in various countries. It is considered safe practice and brings benefits to the laboratory and the patient.Compatibility testing is only one element of the blood transfusion procedure; the others are equally as important and include correct patient identification at the time of collection of the blood sample and at the administration of the blood transfusion.
Refractory hyperhaemolysis in a patient with β‐thalassaemia major
Authors: Grainger J. D. , Makar Y. , McManus A. , Wynn R. 
Published: March 2003

. We report the case of a 1‐year‐old girl with newly diagnosed β‐thalassaemia major. Following an initial blood transfusion with phenotypically matched blood, she developed a haemolytic anaemia which progressed with subsequent transfusions.The Direct Antiglobulin test (DAT) was strongly positive with C3d and weakly with IgG. The only free antibodies detected were a weak anti‐H and a weak cold auto‐antibody, which did not exhibit a wide thermal range. The indirect Donath–Landsteiner and Ham's tests were negative.There was no sustained clinical response to steroids, immunoglobulin infusions or splenectomy. An HLA identical sibling donor was available for allogeneic bone marrow transplantation (BMT) and the haemolysis resolved during the immunosuppressive transplant conditioning.Such hyperhaemolysis without significant red cell alloantibodies has previously been reported in patients with sickle cell anaemia, but only rarely in patients with β‐thalassaemia major.