bluuebunny/crossref_metadata_2025 huggingface dataset:
Proteomic Approach to Identify Novel Mitochondrial Proteins in Arabidopsis
Authors: Kruft Volker , Eubel Holger , Jänsch Lothar , Werhahn Wolf , Braun Hans-Peter
Published: November 2008

An Arabidopsis mitochondrial proteome project was started for a comprehensive investigation of mitochondrial functions in plants. Mitochondria were prepared from Arabidopsis stems and leaves or from Arabidopsis suspension cell cultures, and the purity of the generated fractions was tested by the resolution of organellar protein complexes applying two-dimensional blue-native/N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine (Tricine) sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The Arabidopsis mitochondrial proteome was analyzed by two-dimensional isoelectric focusing/ Tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 650 different proteins in a pI range of pH 3 to 10 were separated on single gels. Solubilization conditions, pH gradients for isoelectric focusing, and gel staining procedures were varied, and the number of separable proteins increased to about 800. Fifty-two protein spots were identified by immunoblotting, direct protein sequencing, and mass spectrometry. The characterized proteins cooperate in various processes, such as respiration, citric acid cycle, amino acid and nucleotide metabolism, protection against O2, mitochondrial assembly, molecular transport, and protein biosynthesis. More than 20% of the identified proteins were not described previously for plant mitochondria, indicating novel mitochondrial functions. The map of the Arabidopsis mitochondrial proteome should be useful for the analysis of knockout mutants concerning nuclear-encoded mitochondrial genes. Considerations of the total complexity of the Arabidopsis mitochondrial proteome are discussed. The data from this investigation will be made available athttp://www.gartenbau.uni-hannover.de/genetik/AMPP.
Sodium Uptake in Arabidopsis Roots Is Regulated by Cyclic Nucleotides
Authors: Maathuis Frans J.M. , Sanders Dale
Published: November 2008

Sodium uptake from the soil is a major cause of salinity toxicity in plants, yet little is known about the mechanisms that underlie Na+ influx. We have characterized voltage independent channels (VICs) in Arabidopsis roots that are thought to contribute to Na+ entry. VICs showed no selectivity among monovalent cations, and their gating was found to be voltage independent. However, VIC open probability showed sensitivity to cyclic nucleotides. The presence of micromolar concentrations of cAMP or cGMP at the cytoplasmic side of the plasma membrane evoked a rapid decrease in channel open probability. In accord with predictions from electrophysiological data, our results show that short-term unidirectional Na+ influx is also reduced in the presence of cyclic nucleotides. Moreover, addition of membrane permeable cyclic nucleotides during growth assays improved plant salinity tolerance, which corresponded with lower levels of Na+ accumulation in plants. In summary, these data imply that Arabidopsis plants may contain a cyclic nucleotide-based signaling pathway that directly affects Na+ transport via VICs.
DEX1, a Novel Plant Protein, Is Required for Exine Pattern Formation during Pollen Development in Arabidopsis
Authors: Paxson-Sowders Dawn M. , Dodrill Craig H. , Owen Heather A. , Makaroff Christopher A.
Published: November 2008

To identify factors that are required for proper pollen wall formation, we have characterized the T-DNA-tagged, dex1mutation of Arabidopsis, which results in defective pollen wall pattern formation. This study reports the isolation and molecular characterization of DEX1 and morphological and ultrastructural analyses of dex1 plants.DEX1 encodes a novel plant protein that is predicted to be membrane associated and contains several potential calcium-binding domains. Pollen wall development in dex1 plants parallels that of wild-type plants until the early tetrad stage. Index1 plants, primexine deposition is delayed and significantly reduced. The normal rippling of the plasma membrane and production of spacers observed in wild-type plants is also absent in the mutant. Sporopollenin is produced and randomly deposited on the plasma membrane in dex1 plants. However, it does not appear to be anchored to the microspore and forms large aggregates on the developing microspore and the locule walls. Based on the structure of DEX1 and the phenotype of dex1 plants, several potential roles for the protein are proposed.
Sodium Fluxes through Nonselective Cation Channels in the Plasma Membrane of Protoplasts from Arabidopsis Roots
Authors: Demidchik Vadim , Tester Mark
Published: November 2008

The aim of the present work was to characterize Na+currents through nonselective cation channels (NSCCs) in protoplasts derived from root cells of Arabidopsis. The procedure of the protoplast isolation was modified to increase the stability of Arabidopsis root protoplasts in low external Ca2+ by digesting tissue in elevated Ca2+. Experiments in whole-cell and outside-out modes were carried out. We found that Na+ currents in Arabidopsis root protoplasts were mediated by cation channels that were insensitive to externally applied tetraethylammonium+ and verapamil, had no time-dependent activation (permanently opened or completely activated within 1–2 ms), were voltage independent, and were weakly selective for monovalent cations. The selectivity sequence was as follows: K+ (1.49) > NH4  + (1.24) > Rb+ (1.15) ≈ Cs+ (1.10) ≈ Na+ (1.00) > Li+ (0.73) > tetraethylammonium+ (0.47). Arabidopsis root NSCCs were blocked by H+ (pK ≈ 6.0), Ca2+(K1/2 ≈ 0.1 mm), Ba2+, Zn2+, La3+, Gd3+, quinine, and the His modifier diethylpyrocarbonate. They were insensitive to most organic blockers (nifedipine, verapamil, flufenamate, and amiloride) and to the SH-group modifier p-chloromercuriphenyl sulfonic acid. Voltage-insensitive, Ca2+-sensitive single channels were also resolved. Properties of Arabidopsis root NSCCs are discussed and compared with characteristics of similar conductances studied previously in plants and animals. It is suggested that NSCCs present a distinct group of plant ion channels, mediating toxic Na+ influx to the cell and probably having other important roles in physiological processes of plants.
Colocalization of Plastid Division Proteins in the Chloroplast Stromal Compartment Establishes a New Functional Relationship between FtsZ1 and FtsZ2 in Higher Plants
Authors: McAndrew Rosemary S. , Froehlich John E. , Vitha Stanislav , Stokes Kevin D. , Osteryoung Katherine W.
Published: November 2008

Chloroplast division is driven by a macromolecular complex containing components that are positioned on the cytosolic surface of the outer envelope, the stromal surface of the inner envelope, and in the intermembrane space. The only constituents of the division apparatus identified thus far are the tubulin-like proteins FtsZ1 and FtsZ2, which colocalize to rings at the plastid division site. However, the precise positioning of these rings relative to the envelope membranes and to each other has not been previously defined. Using newly isolated cDNAs with open reading frames longer than those reported previously, we demonstrate here that both FtsZ2 proteins in Arabidopsis, like FtsZ1 proteins, contain cleavable transit peptides that target them across the outer envelope membrane. To determine their topological arrangement, protease protection experiments designed to distinguish between stromal and intermembrane space localization were performed on both in vitro imported and endogenous forms of FtsZ1 and FtsZ2. Both proteins were shown to reside in the stromal compartment of the chloroplast, indicating that the FtsZ1- and FtsZ2-containing rings have similar topologies and may physically interact. Consistent with this hypothesis, double immunofluorescence labeling of various plastid division mutants revealed precise colocalization of FtsZ1 and FtsZ2, even when their levels and assembly patterns were perturbed. Overexpression of FtsZ2 in transgenic Arabidopsis inhibited plastid division in a dose-dependent manner, suggesting that the stoichiometry between FtsZ1 and FtsZ2 is an important aspect of their function. These studies raise new questions concerning the functional and evolutionary significance of two distinct but colocalized forms of FtsZ in plants and establish a revised framework within which to understand the molecular architecture of the plastid division apparatus in higher plants.
Diurnal and Circadian Regulation of Putative Potassium Channels in a Leaf Moving Organ
Authors: Moshelion Menachem , Becker Dirk , Czempinski Katrin , Mueller-Roeber Bernd , Attali Bernard , Hedrich Rainer , Moran Nava
Published: November 2008

In a search for potassium channels involved in light- and clock-regulated leaf movements, we cloned four putative K channel genes from the leaf-moving organs, pulvini, of the legume Samanea saman. The S. saman SPOCK1 is homologous to KCO1, an Arabidopsis two-pore-domain K channel, the S. saman SPORK1 is similar to SKOR and GORK, Arabidopsis outward-rectifying Shaker-like K channels, and theS. saman SPICK1 and SPICK2 are homologous to AKT2, a weakly-inward-rectifying Shaker-like Arabidopsis K channel. All four S. saman sequences possess the universal K-channel-specific pore signature, TXXTXGYG, strongly suggesting a role in transmembrane K+ transport. The fourS. saman genes had different expression patterns within four leaf parts: ‘extensor’ and ‘flexor’ (the motor tissues), the leaf blades (mainly mesophyll), and the vascular bundle (‘rachis’). Based on northern blot analysis, their transcript level was correlated with the rhythmic leaf movements: (a) all four genes were regulated diurnally (Spick2, Spork1, andSpock1 in extensor and flexor, Spick1 in extensor and rachis); (b) Spork1 andSpock1 rhythms were inverted upon the inversion of the day-night cycle; and (c) in extensor and/or flexor, the expression ofSpork1, Spick1, and Spick2was also under a circadian control. These findings parallel the circadian rhythm shown to govern the resting membrane K+permeability in extensor and flexor protoplasts and the susceptibility of this permeability to light stimulation (Kim et al., 1993). Thus,Samanea pulvinar motor cells are the first described system combining light and circadian regulation of K channels at the level of transcript and membrane transport.
Dynamic and Steady-State Responses of Inorganic Nitrogen Pools and NH3 Exchange in Leaves ofLolium perenneandBromus erectusto Changes in Root Nitrogen Supply
Authors: Mattsson Marie , Schjoerring Jan K.
Published: November 2008

Short- and long-term responses of inorganic N pools and plant-atmosphere NH3 exchange to changes in external N supply were investigated in 11-week-old plants of two grass species,Lolium perenne and Bromus erectus, characteristic of N-rich and N-poor grassland ecosystems, respectively. A switch of root N source from NO3  − to NH4  + caused within 3 h a 3- to 6-fold increase in leaf apoplastic NH4  + concentration and a simultaneous decrease in apoplastic pH of about 0.4 pH units in both species. The concentration of total extractable leaf tissue NH4  + also increased two to three times within 3 h after the switch. Removal of exogenous NH4  + caused the apoplastic NH4  + concentration to decline back to the original level within 24 h, whereas the leaf tissue NH4  +concentration decreased more slowly and did not reach the original level in 48 h. After growing for 5 weeks with a steady-state supply of NO3  − or NH4  +, L. perenne were in all cases larger, contained more N, and utilized the absorbed N more efficiently for growth than B. erectus, whereas the two species behaved oppositely with respect to tissue concentrations of NO3  −, NH4  +, and total N. Ammonia compensation points were higher for B. erectus than for L. perenne and were in both species higher for NH4  +- than for NO3  −-grown plants. Steady-state levels of apoplastic NH4  +, tissue NH4  +, and NH3 emission were significantly correlated. It is concluded that leaf apoplastic NH4  + is a highly dynamic pool, closely reflecting changes in the external N supply. This rapid response may constitute a signaling system coordinating leaf N metabolism with the actual N uptake by the roots and the external N availability.
Differential Substrate Inhibition Couples Kinetically Distinct 4-Coumarate:Coenzyme A Ligases with Spatially Distinct Metabolic Roles in Quaking Aspen
Authors: Harding Scott A. , Leshkevich Jacqueline , Chiang Vincent L. , Tsai Chung-Jui
Published: November 2008

4-Coumarate:coenzyme A ligase (4CL) activates hydroxycinnamates for entry into phenylpropanoid branchways that support various metabolic activities, including lignification and flavonoid biosynthesis. However, it is not clear whether and how 4CL proteins with their broad substrate specificities fulfill the specific hydroxycinnamate requirements of the branchways they supply. Two tissue-specific 4CLs, Pt4CL1 and Pt4CL2, have previously been cloned from quaking aspen (Populus tremuloides Michx.), but whether they are catalytically adapted for the distinctive metabolic roles they are thought to support is not apparent from published biochemical data. Therefore, single- and mixed-substrate assays were conducted to determine whether the 4CLs from aspen exhibit clear catalytic identities under certain metabolic circumstances. Recombinant Pt4CL1 and Pt4CL2 exhibited the expected preference forp-coumarate in single-substrate assays, but strong competitive inhibition favored utilization of caffeate andp-coumarate, respectively, in mixed-substrate assays. The Pt4CL1 product, caffeoyl-CoA, predominated in mixed-substrate assays with xylem extract, and this was consistent with the near absence of Pt4CL2 expression in xylem tissue as determined by in situ hybridization. It is interesting that the Pt4CL2 product p-coumaroyl-CoA predominated in assays with developing leaf extract, although in situ hybridization revealed that both genes were coexpressed. The xylem extract and recombinant 4CL1 data allow us to advance a mechanism by which 4CL1 can selectively utilize caffeate for the support of monolignol biosynthesis in maturing xylem and phloem fibers. Loblolly pine (Pinus taeda), in contrast, possesses a single 4CL protein exhibiting broad substrate specificity in mixed-substrate assays. We discuss these 4CL differences in terms of the contrasts in lignification between angiosperm trees and their gymnosperm progenitors.
Molecular Characterization of Two Arabidopsis Ire1 Homologs, Endoplasmic Reticulum-Located Transmembrane Protein Kinases
Authors: Koizumi Nozomu , Martinez Immaculada M. , Kimata Yukio , Kohno Kenji , Sano Hiroshi , Chrispeels Maarten J.
Published: November 2008

A major response of eukaryotic cells to the presence of unfolded proteins in the lumen of the endoplasmic reticulum (ER) is to activate genes that encode ER-located molecular chaperones, such as the binding protein. This response, called the unfolded protein response, requires the transduction of a signal from the ER to the nucleus. In yeast (Saccharomyces cerevisiae) and mammalian cells, an ER-located transmembrane receptor protein kinase/ribonuclease called Ire1, with a sensor domain in the lumen of the ER, is the first component of this pathway. Here, we report the cloning and derived amino acid sequences of AtIre1-1 and AtIre1-2, two Arabidopsis homologs of Ire1. The two proteins are located in the perinuclear ER (based on heterologous expression of fusions with green fluorescent protein). The expression patterns of the two genes (using β-glucuronidase fusions) are nearly nonoverlapping. We also demonstrate functional complementation of the sensor domains of the two proteins in yeast and show that the Ire1-2 protein is capable of autotransphosphorylation. These and other findings are discussed in relation to the involvement of these genes in unfolded protein response signaling in plants.
Extrinsic Photosystem II Carbonic Anhydrase in Maize Mesophyll Chloroplasts
Authors: Lu Yih-Kuang , Stemler Alan J.
Published: November 2008

One form of carbonic anhydrase (CA) has been observed in maize (Zea mays) thylakoids and photosystem II (PSII)-enriched membranes. Here, we show that an antibody produced against a thylakoid lumen-targeted CA found in Chlamydomonas reinhardtiireacts with a single 33-kD polypeptide in maize thylakoids. With immunoblot analysis, we found that this single polypeptide could be identified only in mesophyll thylakoids and derived PSII membranes, but not in bundle sheath thylakoids. Likewise, a CA activity assay confirmed a large amount of activity in mesophyll, but not in bundle sheath membranes. Immunoblot analysis and CA activity assay showed that the maximum CA can be obtained in the supernatant of the PSII-enriched membranes washed with 1 m CaCl2, the same procedure used to remove all extrinsic lumenal proteins from PSII. Because this CA reacts with an antibody to lumen-directed CA inC. reinhardtii, and because it can be removed with 1m CaCl2 wash, we refer to it tentatively as extrinsic CA. This is to distinguish it from another form of CA activity tightly bound to PSII membranes that remains after CaCl2 wash, which has been described previously. The function of extrinsic CA is not clear. It is unlikely to have the same function as the cytoplasmic CA, which has been proposed to increase the HCO3  − concentration for phosphoenolpyruvate carboxylase and the C4 pathway. We suggest that because the extrinsic CA is associated only with thylakoids doing linear electron flow, it could function to produce the CO2 or HCO3  − needed for PSII activity.
Elemental Sulfur and Thiol Accumulation in Tomato and Defense against a Fungal Vascular Pathogen
Authors: Williams Jane S. , Hall Sharon A. , Hawkesford Malcolm J. , Beale Michael H. , Cooper Richard M.
Published: November 2008

The occurrence of fungicidal, elemental S is well documented in certain specialized prokaryotes, but has rarely been detected in eukaryotes. Elemental S was first identified in this laboratory as a novel phytoalexin in the xylem of resistant genotypes of Theobroma cacao, after infection by the vascular, fungal pathogen Verticillium dahliae. In the current work, this phenomenon is demonstrated in a resistant line of tomato,Lycopersicon esculentum, in response to V. dahliae. A novel gas chromatography-mass spectroscopy method using isotope dilution analysis with 34S internal standard was developed to identify unambiguously and quantify 32S in samples of excised xylem. Accumulation of S in vascular tissue was more rapid and much greater in the disease-resistant than in the disease-susceptible line. Levels of S detected in the resistant variety (approximately 10 μg g−1 fresh weight excised xylem) were fungitoxic to V. dahliae (spore germination was inhibited >90% at approximately 3 μg mL−1). Scanning electron microscopy-energy dispersive x-ray microanalysis confirmed accumulation of S in vascular but not in pith cells and in greater amounts and frequency in the Verticillium spp.-resistant genotype. More intensive localizations of S were occasionally detected in xylem parenchyma cells, vessel walls, vascular gels, and tyloses, structures in potential contact with and linked with defense toV. dahliae. Transient increases in concentrations of sulfate, glutathione, and Cys of vascular tissues from resistant but not susceptible lines after infection may indicate a perturbation of S metabolism induced by elemental S formation; this is discussed in terms of possible S biogenesis.
The N-Terminal Region of Arabidopsis Cystathionine γ-Synthase Plays an Important Regulatory Role in Methionine Metabolism
Authors: Hacham Yael , Avraham Tal , Amir Rachel
Published: November 2008

Cystathionine γ-synthase (CGS) is a key enzyme of Met biosynthesis in bacteria and plants. Aligning the amino acid sequences revealed that the plant enzyme has an extended N-terminal region that is not found in the bacterial enzyme. However, this region is not essential for the catalytic activity of this enzyme, as deduced from the complementation test of an Escherichia coli CGS mutant. To determine the function of this N-terminal region, we overexpressed full-length Arabidopsis CGS and its truncated version that lacks the N-terminal region in transgenic tobacco (Nicotiana tabacum) plants. Transgenic plants expressing both types of CGS had a significant higher level of Met,S-methyl-Met, and Met content in their proteins. However, although plants expressing full-length CGS showed the same phenotype and developmental pattern as wild-type plants, those expressing the truncated CGS showed a severely abnormal phenotype. These abnormal plants also emitted high levels of Met catabolic products, dimethyl sulfide and carbon disulfide. The level of ethylene, the Met-derived hormone, was 40 times higher than in wild-type plants. Since the alien CGS was expressed at comparable levels in both types of transgenic plants, we further suggest that post-translational modification(s) occurs in this N-terminal region, which regulate CGS and/or Met metabolism. More specifically, since the absence of the N-terminal region leads to an impaired Met metabolism, the results further suggest that this region plays a role in protecting plants from a high level of Met catabolic products such as ethylene.
Signal Transduction in Maize and Arabidopsis Mesophyll Protoplasts
Authors: Sheen Jen
Published: November 2008

Plant protoplasts show physiological perceptions and responses to hormones, metabolites, environmental cues, and pathogen-derived elicitors, similar to cell-autonomous responses in intact tissues and plants. The development of defined protoplast transient expression systems for high-throughput screening and systematic characterization of gene functions has greatly contributed to elucidating plant signal transduction pathways, in combination with genetic, genomic, and transgenic approaches.
Home Alone: Children as Caretakers in León, Nicaragua
Authors: Dahlblom Kjerstin , Herrara Andres Rodríguez , Peña Rodolfo , Dahlgren Lars
Published: November 2008

This article seeks to explore and understand the life situations of sibling caretakers in poor areas in León, Nicaragua. The every day lives for caretakers were studied through observations and interviews with children, informants and parents. The children themselves were satisfied and proud to be trusted as caretakers and felt useful in contributing to their families’ livelihood. However, in a life course perspective the caretaking role implies a narrowing of life options. Early on they seem to acquire essential life skills but as they grow older many are at risk of falling behind due to their marginalised situation and lack of basic education.
Alcohol consumption and mortality and hospital admissions in men from the Midspan Collaborative cohort study
Authors: Hart Carole L. , Smith George Davey
Published: November 2008

Aims  To investigate the relationships between alcohol consumption and mortality and morbidity risk by specific causes.

Design  Prospective cohort study.

Setting  Twenty‐seven work‐places in West and Central Scotland.

Participants  A total of 6000 men aged 21–64 years at screening in 1970–1973, median follow‐up 29 years.

Measurements  Relative rates, using Cox's proportional hazard models, by weekly reported units of alcohol consumption for all cause, coronary heart disease (CHD), stroke, respiratory, digestive, liver disease and alcohol‐related causes of mortality and for specific causes of acute hospital admissions.

Findings  Mortality risk was increased for men drinking 15–21 or more units per week for all causes, stroke, liver disease and alcohol‐related causes. For respiratory mortality, drinkers of 35 or more units had double the risk compared to non‐drinkers. CHD mortality showed increasing trends with consumption when adjusted for age and after full adjustment showed no clear patterns, although the 8–14 units group had a lower risk than non‐drinkers [relative rate 0.81 (0.68–0.97)]. Hospital admissions had similar patterns to mortality for stroke and liver disease. Increased risk began at 8–14 units for alcohol‐related admissions, and at 15–21 units for respiratory admissions. Non‐drinkers had higher risks of having a CHD admission than drinkers and there were decreasing trends with increasing consumption (P = 0.019).

Conclusions  Consumption of 15–21 units per week and over was associated with increased mortality from most causes and increased risk of hospital admissions from stroke, liver disease and respiratory diseases. Alcohol‐related admissions were raised from 8 to 14 units. Alcohol use may have been under‐reported in our study, but it was similar to other studies of the time. The apparent protective effect of alcohol with CHD admissions could be due partly to detrimental effects of heavy drinking causing sudden deaths. The associations, including that with respiratory disease, may arise from inadequate adjustment for confounding by other factors such as smoking.
Mesh selection in a sea trout, Salmo trutta L., commercial seine net fishery
Authors: EVANS D.M. , MEE D.M. , CLARKE D.R.K.
Published: November 2008

Abstract The length distribution of adult sea trout, Salmo trutta L., from a commercial seine net fishery using a nominal minimum mesh size of 50 mm or 102 mm is described. The smaller mesh size captured sea trout larger than 210 mm whilst the larger mesh size caught sea trout mainly above 400 mm, with no fish below 320 mm. A sea trout length/ girth relationship is described, and coupled with biological data allowed the calculation of mesh sizes for the appropriate escapement of different sea ages of sea trout.
Target spawning requirements for Atlantic salmon, Salmo salar L., in Newfoundland rivers
Authors: O'CONNELL M.F. , DEMPSON J.B.
Published: November 2008

Abstract In recent years, there has been increasing pressure from user groups in Newfoundland and Labrador, Canada, to manage Atlantic salmon, Salmo salar L., on a river‐specific basis. The requirement to maximize benefits to users while ensuring that conservation goals are met has resulted in an initiative to develop river‐specific target spawning requirements. In Newfoundland, anadromous juvenile Atlantic salmon make widespread use of lacustrine habitat for rearing. Depending on the river, lacustrine habitat can account for a substantial proportion of total production. Therefore, target spawning requirements for a number of rivers in several management areas were derived in terms of the contribution of both riverine and lacustrine habitats. The approach adopted, and derivations of associated parameter values, are reviewed, and limitations and research needs are discussed.
Recreational fishing in Norway from 1970 to 1993: trends and geographical variation
Authors: AAS Ø.
Published: November 2008

Abstract Participation in recreational fishing by Norwegians and geographical differences in fishing behaviour in Norway were investigated from 1970 to 1993 by comparing results from several household surveys at the national level and in different municipalities. Approximately 50% of the adult population fish every year. Only slight changes in participation rates were observed between 1970–1993, but considerable local variation in rates of participation and type of fishing were found. Participation rates among people living in northern Norway and in rural municipalities was higher than among people living in southern Norway and urban citizens. Among people living in the capital city, Oslo, the rate of participation was particularly low. Recreational fishing in Norway includes angling as well as subsistence fishing. Large geographical variation in fishing, continuing urbanization and an increasing population of elderly people should be taken into account by managers when developing a recreational fisheries strategy for the future.
Comparison of two methods of sub‐sea sampling of the Guernsey ormer, Haliotis tuberculata L.
Authors: FINDLAY M. , WILLERTON P.
Published: November 2008

Abstract The ormer, Haliotis tuberculata L., is the only abalone species found on the coasts of western Europe, its northern most limit of distribution being the Channel Islands. Previous Guernsey ormer population studies were based upon a form of catch‐per‐unit‐effort sampling where the unit of effort was one diver, searching the substrate for 5 min continuously. An ormer population survey was carried out in the waters around Guernsey, using this former method concurrent with an alternative system of sampling by area using 10 m2 quadrats at randomly selected locations. The published results of a series of earlier surveys include a measure of ormer density m‐2 which, along with knowledge of the extent of suitable substrate, allows tentatively for absolute abundance to be estimated. This study demonstrates that an estimate obtained in this way may be unreliable. Statistical comparison of the population size structures derived from the two different sampling methods also showed considerable inconsistency. The implications of this for management of the Guernsey ormer stock are considered.
Impact of Oreochromis mossambicus × O. niloticus (Pisces: Cichlidae) hybridization on population reproductive potential and long‐term influence on a reservoir fishery
Authors: AMARASINGHE U.S. , DE SILVA S.S.
Published: November 2008

Abstract Exotic cichlids, introduced to Asia during the second half of the twentieth century, contribute significantly to the reservoir fisheries in the region. The two major cichlid species, Oreochromis mossambicus (Peters) and O. niloticus (L.), tend to interbreed easily. In Sri Lankan reservoirs, introgressive hybridization of these two cichlids takes place. The reproductive biology of O. mossambicus, O. niloticus and their hybrids in three reservoirs in Sri Lanka was evaluated. An imbalance in sex ratio with male dominance was evident. The estimated fecundity for 20‐cm fish, using fecundity‐total length relationships for various populations, indicated that there was a decline in fecundity in hybrid forms. It is hypothesized that the long‐term effect of crosshybridization between the two cichlids might lead to a decline in fish yields in perennial reservoirs of Sri Lanka. The importance of the findings of the present study for the management of the reservoir fisheries in Asia is highlighted.
Stock enhancement in a commercial mullet, Mugil cephalus L., fishery in Hawaii
Authors: ARCE K.M. LEBER & S.M.
Published: November 2008

Abstract This study showed that cultured striped mullet, Mugil cephalus L., released as juveniles can make a significant contribution to landings in an island commercial fishery. Following pilot hatchery releases from 1990 to 1993, striped mullet fisheries in Kaneohe Bay, Hawaii, USA, were sampled to recover cultured fish from the bay‐wide catch. Direct sampling of 181 fishing trips resulted in recovery of 211 cultured striped mullet. By autumn 1994, cultured fish comprised 13.0% (2.8%) of the commercial mullet catch in Kaneohe Bay, and the percentage was increasing logarithmically. This study corroborated predictions from previous studies of juveniles about effects of release strategies on survival of cultured mullet. Following summer releases, recapture rates were strongly affected by fish size‐at‐release, with a critical release size of 60 mm total length (the smallest size released that was subsequently detected in the fishery). Over 30 000 juveniles stocked in 1990 (but not in a nursery habitat preferred by striped mullet) apparently suffered complete mortality.
Bacterial ‘cosmopolitanism’ and importance of local environmental factors for community composition in remote high‐altitude lakes
Authors: SOMMARUGA RUBEN , CASAMAYOR EMILIO O.
Published: November 2008

1. In October 2004, plankton samples were collected from six permanent lakes located between 4960 and 5440 m a.s.l. in the Mount Everest region (Nepal) to assess how spatial and local environmental factors affect natural bacterial community composition. Fingerprinting analysis of the bacterial 16S rRNA gene fragment was done by denaturing gradient gel electrophoresis (DGGE).

2. The number of DGGE bands (range: 12–23) was not correlated with lake area or remoteness, but there was a strong negative correlation with the ratio of catchment to lake area (r = −0.826, P < 0.05), suggesting that hydraulic retention time affects the establishment of the bacterial community in these seepage lakes.

3. Most dominant sequences belonged to Betaproteobacteria except in two lakes where members of Bacteroidetes made the largest relative contribution. Up to 81% of the phylotypes had high similarity (>98 to 100%) in partial 16S rRNA gene sequence to those reported from other alpine lakes and glaciers around the world, suggesting the presence of ‘cosmopolitan’ bacteria.

4. An analysis based on dissimilarity matrices and the Mantel test revealed the existence of dissimilarities in bacterial community composition related to geographical distance over a small spatial scale (<6 km), but determined by local environmental constraints.

5. Our results suggest that several bacterial phylotypes are ubiquitous in the freshwater aquatic realm, but taxon sorting by local environmental constraints is important.
The quality of paediatric nursing care: developing the Child Care Quality at Hospital instrument for children
Authors: Pelander Tiina , Leino‐Kilpi Helena , Katajisto Jouko
Published: November 2008

Title. The quality of paediatric nursing care: developing the Child Care Quality at Hospital instrument for children.

Background. Recent years have shown a growing recognition of children’s rights and the need to listen to and consult with children, especially at an international level, including in the hospital setting. Children’s views should be considered in the planning and delivery of paediatric nursing care. However, previous work has tended to concentrate on medical rather than nursing care.

Method. The CCQH instrument was developed in three phases. First, in 2004 following a literature review and interviews/drawings by hospitalized children (n = 40), the items were designed and an expert panel (n = 7) assessed the instrument’s content validity (phase I). Revisions were made based on children’s interviews (n = 8), children’s questionnaires (n = 41, 16) and nurses’ evaluations (n = 19, 198) in phases II and III in 2004 and 2005 respectively. Construct validity was assessed in phase III by means of principal component analysis. The instrument’s reliability was statistically tested in phases II and III.

Findings. The main quality categories were nurse characteristics, nursing activities and environment. For each category, Cronbach’s alpha values improved during the development process. Principal component analysis supported the theoretical construct of the subcategories in the nursing activities and environment categories.

Conclusion. The CCQH questionnaire is a promising instrument for use among children. Future research is needed to evaluate its suitability for completion by children of varying ages and in different cultures and healthcare settings.
Judging the quality of clinical audit by general practitioners: a pilot study comparing the assessments of medical peers and NHS audit specialists
Authors: Bowie Paul , McKay John , Murray Lilian , Lough Murray
Published: November 2008

Rationale, aims and objectives  Clinical audit informs general practitioner (GP) appraisal and will provide evidence of performance for revalidation in the UK. However, objective evidence is now required. An established peer assessment system may offer an educational solution for making objective judgements on clinical audit quality. National Health Service (NHS) clinical audit specialists could potentially support this system if their audit assessments were comparable with established medical peer assessors. The study aimed to quantify differences between clinical audit specialists and medical peer assessors in their assessments of clinical audit projects.

Methods  A comparison study of the assessment outcomes of clinical audit reports by two groups using appropriate assessment instruments was conducted. Mean scores were compared and 95% confidence intervals (CIs) and limits of agreement calculated. A two‐point mean difference would be relevant.

Results  Twelve significant event analysis (SEA) reports and 12 criterion audit projects were assessed by 11 experienced GP assessors and 10 NHS audit specialist novice assessors. For SEA, the mean score difference between groups was <1.0. The 95% CI for bias was −0.1 to 0.5 (P = 0.14). Limits of agreement ranged from −0.7 to 1.2. For criterion audit, a mean score difference of ≤1.0 was calculated for seven projects and scores between 1.1 and 1.9 for four. The 95% CI for bias was 0.8 to 1.5 (P < 0.001). Limits of agreement ranged from −2.5 to −0.0.

Conclusions  The study findings suggest that a sample of NHS clinical audit specialists can give numerically accurate feedback scores to GPs on the quality of their clinical audit activity compared with established peer assessors as part of the model outlined.
Histochemical Detection of Glycoconjugates in the Canine Epididymis
Authors: Schick B. , Habermann F. , Sinowatz F.
Published: November 2008

A histochemical study using fluorescein isothiocyanate (FITC)‐labelled lectins to identify glycoconjugates present in the efferent ductules and the three segments of the ductus epididymis (initial, middle and terminal segment) of dogs was carried out. The lectins used were: mannose‐binding lectins (Con A, LCA and PSA), galactose‐binding lectins (PNA, RCA), N‐acetylgalactosamine‐binding lectins (DBA, SBA, SJA and GSL I), N‐acetylglucosamine‐binding lectins (WGA and WGAs), fucose‐binding lectins (UEA) and lectins which bind to complex carbohydrate configurations (PHA E and PHA L). The lectin‐binding pattern in the canine epididymis presents similarities and differences to those observed in other mammalian species. The ductuli efferentes distinctly stained with most of the lectins used, whereas in the ductus epididymis a segment specific staining pattern was observed. Whereas principal cells of the ductus epididymis stained clearly with several FITC‐labelled lectins (WGA, UEA and PHA‐L), basal cells showed only a significant binding of Con A.
Water Deficit Reduced Fertility of Young Microspores Resulting in a Decline of Viable Mature Pollen and Grain Set in Rice
Authors: Nguyen G. N. , Sutton B. G.
Published: November 2008

Pollen formation in rice (Oryza sativa L.) is highly vulnerable to environmental stresses such as heat, chilling and drought. In rice plants exposed to drought during male reproductive development, the most obvious damage often observed is a decline in the number of engorged pollen and grain set. This has been well characterized in rice under chilling and to a lesser extent under drought stress. Moreover, detailed literature on the immediate effects of drought on developing young microspores in rice is still limited. Here, we report findings from experiments on rice plants exposed to water deficit for three consecutive days during early stages of anther development. When the osmotic potential of the growing medium was equal to or less than −0.5 MPa, as induced by polyethylene glycol, the leaf water potential was significantly lowered and grain set was reduced. A strong correlation between grain set and viable young microspores (P < 0.001, r2 = 0.8223) indicates that water deficit immediately reduced fertility of rice plants at the time of exposure. This result suggests a new underlying mechanism of water deficit‐induced pollen abortion in rice.
Barley Root Morphology Affects the Zoospore Production Rate by the Obligate Root Parasite and Soil‐borne Virus Vector Polymyxa graminis
Authors: McGrann Graham R. D. , Mutasa‐Göttgens Effie S.
Published: November 2008

Plasmodiophorid parasites in the genus Polymyxa infect roots by means of zoospores and transmit more than 15 soil‐borne viruses in a wide range of arable crops. Barley mutants, selected for variations in root hair formation and morphology, were used to demonstrate that root hairs were important but not essential for infection by zoospores of Polymyxa graminis. The relative rates of parasite establishment in roots were determined indirectly as the relative number of zoospores released by roots inoculated with P. graminis in wild‐type and mutant plants. The number of P. graminis zoospores released per gram root fresh weight was significantly reduced in brb and rhl1.b mutants, both of which have no root hairs. This is an important result because there are no natural sources of resistance to P. graminis. Reducing infection levels of viruliferous P. graminis will slow the build up of virus inoculum in the soil and the selection of strains able to overcome the virus resistance in current cereal cultivars.
Reproductive Performance of Rabbit Does Artificially Inseminated via Intravaginal Administration of [des‐Gly 10, d‐Ala6]‐LHRH Ethylamide as Ovulation Inductor
Authors: Quintela LA , Peña AI , Vega MD , Gullón J , Prieto C , Barrio M , Becerra JJ , Herradón PG
Published: November 2008

Contents

This study was aimed to evaluate the reproductive performance of rabbit does artificially inseminated (AI) with a GnRH analogue [des‐Gly10, d‐Ala6]‐LHRH. ethylamide to induce ovulation by intravaginal administration, delivered in the seminal dose. In a preliminary experiment, 39 does were divided into three groups (n = 13) that, at the time of AI, received the following ovulation induction treatments: (i) control group: 20 μg of gonadorelin administered intramuscularly; (ii) 25 μg of the GnRH analogue added to the seminal dose; (iii) 30 μg of the GnRH analogue added to the seminal dose. Fertility did not differ between the three groups (control: 80.6%, group 2: 82.8%, group 3: 73.3%). In a second experiment, a large‐scale field trial was conducted to test the use of 25 μg of the GnRH analogue [des‐Gly10, d‐Ala6]‐LHRH ethylamide delivered in the seminal dose (n = 270) against 20 μg of gonadorelin administered intramuscularly. Fertility was higher (p < 0.05) when ovulation was induced by intravaginal administration of the GnRH agonist (91.1% vs 85.6%). Prolificacy or mortality at birth was never affected by the ovulation induction treatments. In a third experiment, two groups of does [control group (n = 39): ovulation was induced using 20 μg of gonadorelin administered intramuscularly; treatment group (n = 40): ovulation was induced using 25 μg of [(des‐Gly10, d‐Ala6)‐LHRH ethylamide added to the seminal dose] were inseminated at 42‐day intervals for five successive AI cycles, to test the response to the GnRH agonist after repeated intravaginal administration to the same animals. Fertility and prolificacy were not influenced by the ovulation induction treatment neither there was an interaction between treatment and parity. The last experiment was aimed to determine whether it could be possible to add the GnRH agonist to the semen in the AI Center, just after semen collection and dilution, or it would have to be added in the farm, immediately before AI. Kindling rates did not significantly differ when ovulation was induced by intramuscular injection of gonadorelin (84.5%) or when the GnRH agonist was added to the seminal dose just at the moment (93.8 %) or 24 h before AI (90.4 %), but it was significantly lower when the hormone was added to the semen 32 h before AI (76.3 %). Prolificacy, however, was not influenced by the ovulation induction treatment.
Evaluations of Boar Gonad Development, Spermatogenesis with regard to Semen Characteristics, Libido and Serum Testosterone Levels based on large White Duroc × Chinese Erhualian Crossbred Boars
Authors: Ren D , Xing Y , Lin M , Wu Y , Li K , Li W , Yang S , Guo T , Ren J , Ma J , Lan L , Huang L
Published: November 2008

Contents

Chinese Erhualian pigs are known for prolificacy with distinct reproductive traits compared with Western commercial breeds. In this study, a four‐generation intercross resource population was constructed using White Duroc boars and Chinese Erhualian sows as founder animals, and a total of 14 male reproductive traits were recorded in 411 F2/F3 boars including the testis and epididymis weights, the seminiferous tubular diameter and spermatogenesis at 60, 90 and 300 days of age, semen characteristics, serum testosterone concentration and libido level at 300 days of age. The White Duroc–Erhualian boars showed remarkable segregations in the traits measured except for the seminiferous tubular diameter and had high ratio (13.9%) of the abnormality of spermatogenesis, providing a good experimental population for detecting quantitative trait loci affecting these male reproductive traits. Furthermore, the correlations among nine male reproductive traits at 300 days of age indicated that the testis weight and the body weight were strongly correlated with the sperm production, supporting the two traits as important parameters for boar selection to increase sperm production and ultimately improve boar fertility. The libido level in the White Duroc–Erhualian boars that was evaluated by a new and easily recorded scoring system showed a significant correlation with serum testosterone concentration. Yet, both libido and serum testosterone concentration were not correlated with the sperm production. Results of this study provided new information on the male reproductive physiology and genetics in Chinese Erhualian and White Duroc boars.
Comparison of different predictive models for estimating fish yields in Shahpur Dam, Pakistan
Authors: Janjua Muhammad Yamin , Ahmad Tahira , Gerdeaux Daniel
Published: November 2008

Water reservoirs and dams are major water resources, being diverse in terms of both size and fisheries potential. Reservoir productivity is variable, with significant variations being observed for reservoirs of comparable size and geology, even within the same geographical area. The ability to estimate fish yields through the application of predictive models is an important step for the effective management of fisheries resources in freshwater basins and flowing waters. Various physical, chemical and biological processes establish limits on the yield of commercial fish species. Various physicochemical parameters were measured in this present study during 2001–2002 on a monthly basis for Shahpur Dam in Pakistan. Morphoedaphic indices were derived as MEIt, MEIc and MEIa. A number of different predictive models proposed for different regions are used to predict fish production in Shahpur Dam, for comparison with the actual fish production. From a management perspective, fish yield predictive models based on MEI appeared to be most useful as fish yield predictors.