bluuebunny/crossref_metadata_2025 huggingface dataset:
Metapopulation consequences of site fidelity for colonially breeding mammals and birds
Authors: MATTHIOPOULOS JASON , HARWOOD JOHN , THOMAS LEN
Published: July 2005

Many far‐ranging bird and mammal species aggregate in colonies to breed, and most individuals remain faithful to one colony. Here, we use modelling to explore the consequences of this site fidelity for the metapopulation dynamics of such species.

We develop a spatially explicit model of the annual transfer process between colonies. We apply it to different spatial arrangements of 20 identical colonies and thus demonstrate that connectivity alone can, in the short term, give rise to heterogeneity in colony size.

We place the annual transfer model within a state‐structured population model and examine the consequences of local and global density dependence for long‐term dynamics. For each scenario, we investigate the implications of the strength of site fidelity, the cost of migration and the population's intrinsic growth rate.

Our results suggest that, under local density dependence, site fidelity slows down the colonization process and can temporarily trap the entire population in a subset of the available potential colonies. When site fidelity is strong, the metapopulation follows a step‐like trajectory. Population growth occurs only rarely because individuals must overcome their site‐fidelity to found new colonies. Even though this effect is temporary, it renders the entire metapopulation vulnerable to rare catastrophic collapses.

Under global density dependence, site fidelity imposes competition between colonies for the limiting resource. Stochastic events lead to the dominance of certain colonies and the temporary extinction of others. If site fidelity is strong, it can permanently prevent the metapopulation from occupying all available potential colonies.

We conclude that, irrespective of the mechanism of population regulation, colonially breeding species that show strong site fidelity are likely to occupy only a portion of the breeding habitat available to them.
A common mechanism explaining the evolution of female‐limited and both‐sex Batesian mimicry in butterflies
Authors: OHSAKI NAOTA
Published: July 2005

Batesian mimicry describes the situation in which a palatable mimic resembles an unpalatable model. In some species of butterflies, both sexes mimic, but in others only females do. Two mechanisms have been proposed to generate female‐limited mimicry: sexual selection via female choice, and sexual selection via male–male competition. Each is not satisfactory because of too many exceptions.

I hypothesized that reductions in physiological life span because of mimicry constituted the costs, while extensions of ecological life span because of mimicry constituted the benefits. Mimicry would result from the balance of a costs/benefits relationship; when balances are favourable, mimicry occurs.

Non‐mimetic females of female‐limited mimicry butterfly Papilio polytes lived longer than its mimetic females in a butterfly farm greenhouse. Therefore, reduction in physiological life span must be a cost of mimicry.

Male‐biased sex ratios were found in 11 of the 14 non‐mimetic and non‐model species netted in the Kakamega tropical rainforest in west Kenya, in other one species almost equivalent, and in remaining two species female‐biased. For each species, the sexes netted less frequently had more beak marks than those netted more frequently. That is, the biased sex ratios could be responsible for the higher predation rates of the opposite sex.

Predators may have selectively attacked females with wider thoraxes, which flew at higher levels and flew more quickly. However, attack rates on males of some species may be high or low regardless of thorax width.

As the benefits accrue largely to females with wider thorax due to female‐biased predation, balances of costs/benefits relationships divide participating species into three theoretical groups: those in which the adaptation is favourable for both sexes; favourable only for females; and unfavourable for both sexes.

In female‐limited mimics of five species, thorax widths varied, whereas thoraxes tended to be wider in both‐sex mimics of four species.
Climate predictability and breeding phenology in red deer: timing and synchrony of rutting and calving in Norway and France
Authors: LOE L. E. , BONENFANT C. , MYSTERUD A. , GAILLARD J.‐M. , LANGVATN R. , KLEIN F. , CALENGE C. , ERGON T. , PETTORELLI N. , STENSETH N. C.
Published: July 2005

Timing and synchrony of reproduction are regarded as crucially important factors for fitness in seasonal environments. Natural selection has probably favoured temperate and arctic female herbivores that match reproduction with onset of plant growth in spring. However, breeding synchrony may also be affected by variation in phenotypic quality of females in a population, because females in poor body condition have been found to delay ovulation and subsequent calving.

We compared breeding phenology, i.e. the timing and synchrony of rutting (roaring, sexual aggregation) and calving of red deer (Cervus elaphus L.) in France (latitude: 49°N) and Norway (latitude: 63°N). We hypothesized (H1) that calving and rutting were later at the site with latest onset of plant growth.

We further quantified overall environmental predictability as the sum of annual constancy and seasonality and tested three different (not mutually exclusive) hypotheses about breeding synchrony: (H2a) the population experiencing most seasonal plant phenology should show the highest breeding synchrony; (H2b) overall predictability of plant phenology should determine breeding synchrony; and (H2c) breeding should be more synchronized in the population with lowest female body weight variation within age classes because they ovulate more synchronously.

Calving and rutting, as well as onset of plant phenology, were later in Norway than in France, complying with the first hypothesis. Plant growth in spring was overall more predictable and also more seasonal in Norway than France. Hence we expected higher breeding synchrony in Norway than in France according to H2a and H2b. Variance in female body weight was slightly higher in France than in Norway, which should also cause more synchronized breeding in Norway than in France (H2c). Contrary to all predictions, variance in rutting and calving dates was around two times higher in Norway than in France.

We suggest two alternative explanations of breeding synchrony. A more variable topography in Norway can make optimal birth date more variable on a local scale than in France, thereby maintaining a higher genetic variance for calving date in Norwegian red deer. Further, population age structure may play a role, as ovulation varies according to female age. Clearly, processes of breeding synchrony are far more complex than previously realized.
Pharmacokinetics of imipenem‐cilastatin following intravenous administration in healthy adult horses
Authors: ORSINI J. A. , MOATE P. J. , BOSTON R. C. , NORMAN T. , ENGILES J. , BENSON C. E. , POPPENGA R.
Published: July 2005

In two studies, six healthy adult horses were given imipenem‐cilastatin by slow intravenous (i.v.) infusion at an imipenem dosage of 10 mg/kg (study 1) and 20 mg/kg (study 2). The same horses were used in each dosage schedule, with a 2‐week washout period between studies. In each dosage group, serial blood and synovial fluid samples were collected for 6 h after completion of the infusion. HPLC was used to determine the imipenem concentration in all samples. Imipenem was well tolerated by all horses at both dosages; no adverse effects were noted during the study period or during the 24‐hour postinfusion observation period. The pharmacokinetic profiles of imipenem in the plasma and synovial fluid indicate that an imipenem dosage of 10–20 mg/kg by slow i.v. infusion q6h (every 6 h) is appropriate for most susceptible pathogens.
Efficacy and safety of glycosylated undenatured type‐II collagen (UC‐II) in therapy of arthritic dogs§
Authors: DEPARLE L. A. , GUPTA R. C. , CANERDY T. D. , GOAD J. T. , D'ALTILIO M. , BAGCHI M. , BAGCHI D.
Published: July 2005

In large breed dogs, arthritis is very common because of obesity, injury, aging, immune disorder, or genetic predispositions. This study was therefore undertaken to evaluate clinical efficacy and safety of undenatured type‐II collagen (UC‐II) in obese‐arthritic dogs. Fifteen dogs in three groups received either no UC‐II (Group I) or UC‐II with 1 mg/day (Group II) or 10 mg/day (Group III) for 90 days. Lameness and pain were measured on a weekly basis for 120 days (90 days treatment plus 30 days post‐treatment). Blood samples were assayed for creatinine and blood urea nitrogen (markers of renal injury); and alanine aminotransferase and aspartate aminotransferase (evidence of hepatic injury). Dogs receiving 1 mg or 10 mg UC‐II/day for 90 days showed significant declines in overall pain and pain during limb manipulation and lameness after physical exertion, with 10 mg showed greater improvement. At either dose of UC‐II, no adverse effects were noted and no significant changes were noted in serum chemistry, suggesting that UC‐II was well tolerated. In addition, dogs receiving UC‐II for 90 days showed increased physical activity level. Following UC‐II withdrawal for a period of 30 days, all dogs experienced a relapse of overall pain, exercise‐associated lameness, and pain upon limb manipulation. These results suggest that daily treatment of arthritic dogs with UC‐II ameliorates signs and symptoms of arthritis, and UC‐II is well tolerated as no adverse effects were noted.
Interaction of Rv1625c, a mycobacterial class IIIa adenylyl cyclase, with a mammalian congener
Authors: Guo Ying Lan , Kurz Ursula , Schultz Anita , Linder Jürgen U. , Dittrich Dorothea , Keller Christine , Ehlers Stefan , Sander Peter , Schultz Joachim E.
Published: July 2005

The adenylyl cyclase Rv1625c from Mycobacterium tuberculosis codes for a protein with six transmembrane spans and a catalytic domain, i.e. it corresponds to one half of the pseudoheterodimeric mammalian adenylyl cyclases (ACs). Rv1625c is active as a homodimer. We investigated the role of the Rv1625c membrane domain and demonstrate that it efficiently dimerizes the protein resulting in a 7.5‐fold drop in Km for ATP. Next, we generated a duplicated Rv1625c AC dimer by a head‐to‐tail concatenation. This produced an AC with a domain order exactly as the mammalian pseudoheterodimers. It displayed positive cooperativity and a 60% increase of vmax compared with the Rv1625c monomer. Further, we probed the compatibility of mycobacterial and mammalian membrane domains. The second membrane anchor in the Rv1625c concatamer was replaced with membrane domain I or II of rabbit type V AC. The mycobacterial and either mammalian membrane domains are compatible with each other and both recombinant proteins are active. A M. tuberculosis Rv1625c knockout strain was assayed in a mouse infection model. In vitro growth characteristics and in vivo organ infection and mortality were unaltered in the knockout strain indicating that AC Rv1625c alone is not a virulence factor.
Disruption of the developmental programme of Trypanosoma brucei by genetic ablation of TbZFP1, a differentiation‐enriched CCCH protein
Authors: Hendriks Edward F. , Matthews Keith R.
Published: July 2005

The regulation of differentiation is particularly important in microbial eukaryotes that inhabit multiple environments. The parasite Trypanosoma brucei is an extreme example of this, requiring exquisite gene regulation during transmission from mammals to the tsetse fly vector. Unusually, trypanosomes rely almost exclusively on post‐transcriptional mechanisms for regulated gene expression. Hence, RNA binding proteins are potentially of great significance in controlling stage‐regulated processes. We have previously identified TbZFP1 as a trypanosome molecule transiently enriched during differentiation to tsetse midgut procyclic forms. This small protein (101 amino acids) contains the unusual CCCH zinc finger, an RNA binding motif. Here, we show that genetic ablation of TbZFP1 compromises repositioning of the mitochondrial genome, a specific event in the strictly regulated differentiation programme. Despite this, other events that occur both before and after this remain intact. Significantly, this phenotype correlates with the TbZFP1 expression profile during differentiation. This is the first genetic disruption of a developmental regulator in T. brucei. It demonstrates that programmed events in parasite development can be uncoupled at the molecular level. It also further supports the importance of CCCH proteins in key aspects of trypanosome cell function.
Horizontal transfer of Yersinia high‐pathogenicity island by the conjugative RP4 attB target‐presenting shuttle plasmid
Authors: Antonenka Uladzimir , Nölting Christina , Heesemann Jürgen , Rakin Alexander
Published: July 2005

The high‐pathogenicity island (HPI) encodes a highly efficient yersiniabactin system of iron acquisition responsible for mouse lethality in Yersinia. Although the HPI is widely disseminated among Enterobacteriaceae it lacks functions necessary for its replication and transmission. Therefore, the mechanism of its horizontal transfer and circulation is completely obscure. On the other hand, the HPI is a genetically active island in the bacterial cell. It encodes a functional recombinase and is able to transpose to new targets on the chromosome. Here we report on a possible mechanism of the HPI dissemination based on site‐specific recombination of the excised HPI with the attB‐presenting (asn tRNA gene) RP4 promiscuous conjugative shuttle plasmid. The resulting cointegrate can be transferred by conjugation to a new host, where it dissociates, and the released HPI integrates into any unoccupied asn tRNA gene target in the genome. This mechanism has been proven both with the ‘mini’ island carrying only the attP recognition site and genes coding for recombination enzymes and with the complete HPI labelled with an antibiotic resistance marker. After acquisition of the mobilized complete form of the HPI, the ability of the HPI‐cured Yersinia enterocolitica WA‐TH– strain to produce yersiniabactin has been restored. Such ‘trapping’ of pathogenicity islands and subsequent shuffling to new hosts by a conjugative replicon carrying a suitable attB site could be applied to other functional integrative elements and explain wide dissemination of PAIs.
Polyphosphate kinase regulates error‐prone replication by DNA polymerase IV in Escherichia coli
Authors: Stumpf Jeffrey D. , Foster Patricia L.
Published: July 2005

The ppk gene encodes polyphosphate kinase (Ppk), an enzyme that catalyses the polymerization of inorganic phosphate into long chains of polyphosphate (polyP). An insertion mutation in ppk causes a decrease in adaptive mutation in Escherichia coli strain FC40. Adaptive mutation in FC40 mostly results from error‐prone DNA polymerase IV (Pol IV), encoded by dinB; most of the antimutagenic phenotype of the ppk mutant disappears in a dinB mutant strain. In addition, the ppk mutant causes a decrease in growth‐dependent mutations produced by overexpressing Pol IV. However, the amount of Pol IV protein is unchanged in the ppk mutant strain, indicating that the activity or fidelity of Pol IV is altered. Adaptive mutation is inhibited both by the absence of Ppk, which results in low amounts of polyP, and by overproduction of Ppk, which results in high amounts of polyP, suggesting that an optimal level of polyP is necessary. Taken together, these results suggest a novel mechanism involving polyP that directly or indirectly regulates DNA polymerase activity or fidelity.
BrgE is a regulator of Myxococcus xanthus development
Authors: Pham Vinh D. , Shebelut Conrad W. , Zumstein Erin J. , Singer Mitchell
Published: July 2005

We report here the identification and characterization of a member of the Myxococcus xanthus SdeK signal transduction pathway, BrgE. This protein was identified as an SdeK‐interacting component using a yeast two‐hybrid screen, and we further confirmed this interaction by the glutathione S‐transferase (GST) pulldown assay. Additional yeast two‐hybrid analyses revealed that BrgE preferentially interacts with the putative amino‐terminal sensor domain of SdeK, but not with the carboxy‐terminal kinase domain. A brgE insertion strain was shown to be blocked in development between aggregation and mound formation, and decreased by 50‐fold in viable spore production compared with the parental wild type. These phenotypes are similar to those of sdeK mutants. The brgE mutation also altered expression of a sample of Tn5 lac developmental markers that are also SdeK regulated. Finally, we demonstrated that a brgE sdeK double mutant has a more severe sporulation defect than either of the two single mutants, suggesting that BrgE and SdeK act synergistically to regulate wild‐type levels of sporulation. In sum, these data suggest that BrgE operates as an auxiliary factor to stimulate the SdeK signal transduction pathway by directly binding to the amino‐terminal sensor domain of SdeK.
Large increases in attractant concentration disrupt the polar localization of bacterial chemoreceptors
Authors: Lamanna Allison C. , Ordal George W. , Kiessling Laura L.
Published: July 2005

In bacterial chemotaxis, the chemoreceptors [methyl‐accepting chemotaxis proteins (MCPs)] transduce chemotactic signals through the two‐component histidine kinase CheA. At low but not high attractant concentrations, chemotactic signals must be amplified. The MCPs are organized into a polar lattice, and this organization has been proposed to be critical for signal amplification. Although evidence in support of this model has emerged, an understanding of how signals are amplified and modulated is lacking. We probed the role of MCP localization under conditions wherein signal amplification must be inhibited. We tested whether a large increase in attractant concentration (a change that should alter receptor occupancy from c. 0% to > 95%) would elicit changes in the chemoreceptor localization. We treated Escherichia coli or Bacillus subtilis with a high level of attractant, exposed cells to the cross‐linking agent paraformaldehyde and visualized chemoreceptor location with an anti‐MCP antibody. A marked increase in the percentage of cells displaying a diffuse staining pattern was obtained. In contrast, no increase in diffuse MCP staining is observed when cells are treated with a repellent or a low concentration of attractant. For B. subtilis mutants that do not undergo chemotaxis, the addition of a high concentration of attractant has no effect on MCP localization. Our data suggest that interactions between chemoreceptors are decreased when signal amplification is unnecessary.
Ability of IncP‐9 plasmid pM3 to replicate in Escherichia coli is dependent on both rep and par functions
Authors: Sevastsyanovich Yanina R. , Titok Marina A. , Krasowiak Renata , Bingle Lewis E. H. , Thomas Christopher M.
Published: July 2005

IncP‐9 plasmids are common in Pseudomonas species and can be transferred to other Gram‐negative eubacteria but tend not to be stably maintained outside their natural host genus. A 1.3 kb ori V‐rep fragment from IncP‐9 plasmid pM3 was sufficient for autonomous replication in Pseudomonas putida but not in Escherichia coli. Replication of ori V‐rep in E. coli was restored when additional rep was provided in trans, suggesting that the replication defect resulted from insufficient rep expression from its natural promoter. A promoter deficiency in E. coli was confirmed by reporter gene assays, transcriptional start point mapping and mutation of the promoter recognition elements. Dissection of the pM3 mini‐replicon, pMT2, showed that this replication deficiency in E. coli is suppressed by additional determinants from its par operon: ParB, which can be supplied in trans, and its target, the par operon promoter, required in cis to ori V‐rep. We propose that ParB binding to its target either changes plasmid DNA and thus promoter conformation or by spreading or looping contacts RNAP at the rep promoter so that rep expression is sufficient to activate ori V.
Zap1 activation domain 1 and its role in controlling gene expression in response to cellular zinc status
Authors: Herbig Andrew , Bird Amanda J. , Swierczek Sabina , McCall Keith , Mooney Michelle , Wu Chang‐Yi , Winge Dennis R. , Eide David J.
Published: July 2005

The Zap1 transcription factor is a central player in zinc homeostasis in yeast. This protein regulates the expression of genes involved in zinc accumulation and storage. For most of its target genes, Zap1 activates expression in zinc‐limited cells and this function is inhibited in replete cells. Zap1 has two activation domains, AD1 and AD2, which are independently regulated by zinc status. In this study, we characterized AD1 and its regulation by zinc. AD1 was mapped using deletions to residues 332–402 of Zap1. The region required for the zinc responsiveness of this activation domain, designated ‘ZRDAD1, was mapped to residues 182–502. Thus, AD1 is embedded within its larger zinc‐responsive domain. Using a combination of in silico analysis, random mutagenesis and site‐directed mutagenesis, we identified key residues within ZRDAD1 required for its regulation by zinc. Most of these residues are cysteines and histidines that could potentially serve as Zn(II) ligands. These results suggest that ZRDAD1 senses zinc by direct Zn(II) binding. Consistent with this hypothesis, purified ZRDAD1 bound multiple Zn(II) ions. Finally, our results indicate that, in the context of the full‐length Zap1 protein, AD1 and AD2 are both critical to the full control of gene expression in response to zinc.
Function of the thioredoxin proteins in Cryptococcus neoformans during stress or virulence and regulation by putative transcriptional modulators
Authors: Missall Tricia A. , Lodge Jennifer K.
Published: July 2005

The thioredoxin system, consisting of thioredoxin, thioredoxin reductase and NADPH, is known to protect cells against oxidative stress. This disulphide reducing system is present in Cryptococcus neoformans and consists of two small, dithiol thioredoxin proteins and one thioredoxin reductase. In this study, we describe the thioredoxin proteins, Trx1 and Trx2, and present their importance not only to stress resistance, but also to the virulence of C. neoformans. Using real‐time polymerase chain reaction, we show the induction of both thioredoxin genes during oxidative and nitrosative stress. We describe through deletion studies that the trx1Δ mutant has a severe growth defect and is sensitive to multiple stresses, while the trx2Δ mutant is only sensitive to nitric oxide stress. Using gene replacement studies, we demonstrate that the thioredoxin protein products are partially redundant in function, but there is differential gene regulation which is especially important to nitrosative stress resistance. We have also identified two putative transcription factors, Atf1 and Yap4, which appear to differentially regulate the thioredoxin system under different conditions. Atf1 is necessary for oxidative stress induction, and Yap4 is necessary for nitrosative stress induction of the thioredoxin genes in C. neoformans. While these two putative transcription factors each appear to be dispensable for survival in macrophages and virulence in mice, we show the more highly expressed thioredoxin, TRX1, is necessary for survival of C. neoformans in the oxidative environment of macrophages and important for virulence of this fungal pathogen.
Mycobacterium tuberculosis appears to lack α‐ketoglutarate dehydrogenase and encodes pyruvate dehydrogenase in widely separated genes
Authors: Tian Jing , Bryk Ruslana , Shi Shuangping , Erdjument‐Bromage Hediye , Tempst Paul , Nathan Carl
Published: July 2005

Mycobacterium tuberculosis (Mtb) persists for prolonged periods in macrophages, where it must adapt to metabolic limitations and oxidative/nitrosative stress. However, little is known about Mtb's intermediary metabolism or antioxidant defences. We recently identified a peroxynitrite reductase‐peroxidase complex in Mtb that included products of the genes sucB and lpd, which are annotated to encode the dihydrolipoamide succinyltransferase (E2) and lipoamide dehydrogenase (E3) components of α‐ketoglutarate dehydrogenase (KDH). However, we could detect no KDH activity in Mtb lysates, nor could we reconstitute KDH by combining the recombinant proteins SucA (annotated as the E1 component of KDH), SucB and Lpd. We therefore renamed the sucB product dihydrolipoamide acyltransferase (DlaT). Mtb lysates contained pyruvate dehydrogenase (PDH) activity, which was lost when the dlaT gene (formerly, sucB) was disrupted. Purification of PDH from Mtb yielded AceE, annotated as an E1 component of PDH, along with DlaT and Lpd. Moreover, anti‐DlaT antibody coimmunoprecipitated AceE. Finally, recombinant AceE, DlaT and Lpd, although encoded by genes that are widely separated on the chromosome, reconstituted PDH in vitro with Km values typical of bacterial PDH complexes. In sum, Mtb appears to lack KDH. Instead, DlaT and Lpd join with AceE to constitute PDH.
Wild Mustard (Sinapis arvensis L.) Competition with Three Winter Cereals as Affected by Nitrogen Supply
Authors: Dhima K. , Eleftherohorinos I.
Published: July 2005

Two field experiments were carried out in northern Greece during the 1993–94 and 1994–95 growing seasons to investigate the effect of nitrogen (N) supply on interspecific competition between wild mustard (Sinapis arvensis L.) and wheat (Triticum aestivum L.), barley (Hordeum vulgare =distichum L.) and triticale (Triticosecale). The presence of 140 S. arvensis plants m−2 until early March (averaged over N levels) did not have any adverse effect on the dry weight of all crops. However, its further presence significantly reduced the dry weight of wheat and triticale, but not that of barley. N fertilization (150 kg N ha−1 regardless of application time) slightly increased the dry weight of wheat and triticale grown without weed competition compared with that of control (0 kg N). On the contrary, the presence of wild mustard, until harvest, reduced dry weight of wheat and triticale by 31 and 26 %, respectively, while the corresponding reduction for barley was only 1.5 %. Furthermore, N fertilization (150 kg N ha−1) increased dry weight of wild mustard grown with wheat and triticale by 10 and 16 %, respectively, compared with that of control (0 kg N). Grain yield of wheat and triticale was reduced to 26 and 27 % by the competition of wild mustard, respectively, while the corresponding reduction for barley was only 3.5 %. Moreover, the wild mustard presence reduced total N content of wheat and triticale by 20 and 19 %, respectively, but this was not the case for barley.
Regional Yield Forecasts of Malting Barley (Hordeum vulgare L.) by NOAA‐AVHRR Remote Sensing Data and Ancillary Data
Authors: Weissteiner C. J. , Kühbauch W.
Published: July 2005

Yield forecasts are of major interest to the malting and brewing industry in order to allow the most convenient organization of the respective policy of raw materials. As malting barley is predominantly cultivated in a limited set of growing regions because of its special requirements, yield predictions can be limited to these regions of interest. Within this investigation, malting barley yield forecasts (Hordeum vulgare L.) are performed for typical growing regions in southwestern Germany. Multitemporal remote sensing data on the one hand and ancillary data such as meteorological, phenological, pedological, agro statistical and administrative data on the other hand are used as input data for two versions of prediction models, which are both based on an empirical–statistical modelling approach. The basic version of the yield estimation model is conducted by means of linear correlation of remote sensing data [national oceanic and atmospheric administration‐advanced very high resolution radiometer (NOAA‐AUHRR) normalized difference vegetation index (NDVI) maximum value composites], CORINE land cover data and agro statistical data. In an extended version, meteorological data (temperature and evapotranspiration) and soil data are incorporated. Yield predictions are significantly influenced by the selected time span for NDVI integration. For NDVI time‐integration across the grain‐filling period, the mean deviation of reported and simulated yield is 7.0 and 6.4 %, respectively, for the basic and extended yield estimation model.
Flowering, Pod Set and Reproductive Success in Soya Bean
Authors: Egli D. B.
Published: July 2005

Much of the variation in yield of soya bean [Glycine max (L.) Merrill] and other grain crops is associated with changes in the number of pods and seeds per unit area. Photosynthesis and seed characteristics are the primary determinants of pod and seed number, but recent research suggests that the temporal distribution of flower production may also play an important role. Soya bean has a long flowering period (up to 40 days or more), but most of the flowers are produced in a much shorter time. The length of the period varies among cultivars, growth habits (indeterminate and determinate) and environments. The reproductive success of flowers produced early in the period is usually greater than those produced later. Little is known, however, of the regulation of the temporal distribution of flower production or its potential role in determining pod and seed number at maturity. Research is needed to determine first, if the temporal distribution can be manipulated to increase pod and seed set and secondly, if such increases would result in higher yields.
Fungi Resident in Chickpea Debris and their Suppression of Growth and Reproduction ofDidymella rabieiunder Laboratory Conditions
Authors: Dugan F. M. , Lupien S. L. , Hernandez‐Bello M. , Peever T. L. , Chen W.
Published: July 2005

Fungi colonizing senescent chickpea (Cicer arietinum) stems and postharvest debris from Pullman, WA, were enumerated and identified with the objective of finding species potentially useful for biological control ofDidymella rabiei(conidial state = Ascochyta rabiei), causal agent of Ascochyta blight. In addition toD. rabiei, primary colonizers were, in order of decreasing abundance,Alternaria tenuissima,Al. infectoria,Ulocladium consortiale,Epicoccum purpurascens,U. atrumandFusarium pseudograminearum. Present at lower frequencies wereAl. malorum,Cladosporium herbarum,Aureobasidium pullulans,Clonostachys roseaand miscellaneous anamorphic ascomycetes. On agar media and autoclaved chickpea stems,Au. pullulansconsistently grew faster thanAs. rabiei, and excludedAs. rabieifrom the substrate. When stems received prior inoculation withAu. pullulansorCl. rosea, followed by inoculation with compatible mating types ofD. rabiei, formation of pseudothecia and pycnidia ofD. rabieiwas suppressed. Results suggest thatAu. pullulansandCl. roseacan inhibitAs. rabieiand its sexual stage,D. rabiei, on chickpea debris.Clonostachys roseaformed appressoria on, then invaded,hyphae ofD. rabiei. Small‐scale field experiments usingAu. pullulansandCl. roseahave been initiated.
The Correlation between Severity of Disease Symptoms and the Accumulation of Viral Antigen and Acidic Pathogenesis‐related Proteins in the Leaves of Thorn‐apple Plants Infected with Different Isolates of Potato Virus X
Authors: Sapotsky M. V. , Romanova S. A. , Polyakova A. M. , Malinovsky V. I.
Published: July 2005

The isolates of potato virus X causing disease symptoms of different severity in thorn‐apple plants (Datura stramonium L.) can be categorized in terms of the increase in antigen accumulation, as follows: strong, medium and weak. Extracts from leaves of healthy plants and of those infected with separate virus isolate did not differ in set of acidic pathogenesis‐related (PR) proteins as shown by discontinuous non‐denaturating polyacrylamide gel electrophoresis. Within 2 weeks after inoculation the total content of PR‐proteins in leaves of plants infected with weak or medium isolates was higher than in the healthy ones but after 3 weeks these differences became negligible. The plants infected with the strong isolate had higher total content of PR‐proteins than healthy plants and plants infected with weak or medium isolates during 3 weeks. It is proposed that the greater the damage to the plant caused by virus infection, the more PR‐proteins are accumulated.
Characterization of Variability inRhizoctonia solaniby Using Morphological and Molecular Markers
Authors: Sharma M. , Gupta S. K. , Sharma T. R.
Published: July 2005

Twenty‐four isolates ofRhizoctonia solani(teleomorph:Thanatephorus cucumeris) collected from soil, root and collar rot or foliage blight‐infected plants from several locations of north India were used for the analysis of variability by using morphological and molecular markers. Among the morphological characters, variation was observed in hyphal cell size. Seventeen isolates produced few to abundant, white to dark brown or black, small to large sclerotia generally in the middle of the colony. Genetic variation was also analysed by using 11 random amplified polymorphic DNA primers (RAPD), four universal rice primers (URPs) and two inter simple sequence repeat (ISSR) markers and fingerprint patterns generated for each isolate. The size of amplified DNA bands ranged from 0.3 to 3.5 kb in all the isolates with RAPD, URP and ISSR markers. The isolates obtained from same hosts and same geographical regions showed similarity in DNA fingerprint profiles barring few exceptions. All the isolates were classified into four groups using DNA markers. A comparison of the data obtained from different markers showed that URPs are superior to RAPD, ISSR and morphological markers in detecting genetic variability among the isolates ofR. solani. Hence, use of URP's, which have long primer and higher annealing temperature, would be more sensitive and reliable markers in characterizing genetic diversity inR. solani.
Association of Pepino mosaic virus with Tomato Collapse
Authors: Soler‐Aleixandre S. , López C. , Díez M. J. , de Castro A. Pérez , Nuez F.
Published: July 2005

Since 1998 collapse of tomato plants has been producing significant losses in protected tomato crops along the Spanish Mediterranean coast. Affected plants show sudden and progressive wilt followed by total collapse and death. Analysis of the distribution and accumulation of Pepino mosaic virus (PepMV) in collapsed and non‐collapsed plants and the presence of the virus in all analysed collapsed plants suggests a relationship of this Potexvirus with tomato collapse. The fact that collapse does not occur on PepMV‐free farms reinforces this hypothesis. PepMV‐infected plants showed a necrotic area in the vascular system, mainly in the basal area of the stem. This necrosis was more pronounced in collapsed plants and in the areas with higher viral concentration. Our hypothesis is that tomato collapse would be associated with necrosis of the vascular system caused by PepMV accumulation.
Incidence and Distribution of Viruses Infecting Iranian Vineyards
Authors: Rakhshandehroo F. , Pourrahim R. , Zamani Zadeh H. , Rezaee S. , Mohammadi M.
Published: July 2005

During February and September 2003, the incidence and distribution of viruses infecting grapevine (Vitis vinifera) in Iran was determined. A total of 238 symptomatic and 1314 asymptomatic leaf samples were collected from 56 different vineyards from 10 Iranian provinces and tested by enzyme‐linked immunosorbent assay (ELISA) for the presence of Grapevine fanleaf virus (GFLV), Grapevine fleck virus (GFkV), Grapevine virus A (GVA), Arabis mosaic virus (ArMV), Grapevine leafroll associated virus‐3(GLRaV‐3), Raspberry ringspot virus (RpRSV) and Tobacco ringspot virus (TRSV). Viruses were found in almost all Iranian vineyards examined. The incidence of viruses in a decreasing order was: GFLV (11.1%), GFkV (8.6%), GVA (8.4%), ArMV (6.6%), GLRaV‐3 (6.4%), RpRSV (2.8%) and TRSV (0.35%). GFLV, either alone or in mixed infection in 11.1% of the samples collected nationwide, was the most prevalent virus. In addition, 25 (20%) of 125 symptomatic leaf samples from the Orumeyeh district were shown to contain Tomato ringspot virus. Viruses other than GFLV and GVA are reported from grapevine for the first time in Iran.
Anticoccidial Efficacy of Drinking Water Soluble Diclazuril on Experimental and Field Coccidiosis in Broiler Chickens
Authors: El‐Banna H. A. , El‐Bahy M. M. , El‐Zorba H. Y. , El‐Hady M.
Published: July 2005

Prophylactic and curative capacity of water soluble formulation of Diclazuril (Diclosol 1%) and feed additive form (Clinacox®, 0.5%) were tested against Eimeria infection in broiler chickens. Such testing was performed both experimentally and in the field. Toltrazuril (Baycox, 2.5%) was used as reference control drug. Water soluble formulation of Diclazuril induced a marked inhibitory effect on the different stages of the parasite life cycle in experimentally infected treated birds especially when applied on the day when blood first appeared in the faeces [fifth day post‐infection (d.p.i.)] as well as on the second day of blood dropping (6 d.p.i.). Both tested dosage levels of Diclazuril water soluble formulation in drinking water (5 and 10 ppm) showed the same effect in controlling coccidial infection and reducing the total oocyst numbers, lesion and faecal scores. Moreover, there was no significant difference in the efficacy of water soluble form of Diclazuril and the reference control drug (Toltrazuril, 25 ppm). In addition, testing the water soluble formulation (5 ppm) in naturally infected poultry farm (20 000 birds), showed the same anticoccidial effect observed when using Toltrazuril, as a treatment for coccidiosis. In conclusion, addition of Diclazuril at the dose of 5 ppm in the drinking water of naturally coccidia infected bird induced the same effect as 25 ppm of Toltrazuril as a treatment for coccidiosis in chickens.
Systemic Xanthomatosis Associated with Hyperchylomicronaemia in a Cat
Authors: Chanut F. , Colle M.‐A. , Deschamps J.‐Y. , Albaric O. , Wyers M.
Published: July 2005

We report a case of systemic xanthomatosis in a 4‐month‐old domestic cat. The kitten presented with multiple cutaneous lesions and ‘cream tomato soup’ coloured blood. Necropsy revealed multiple, whitish, nodular lesions, compatible with xanthomas, on most of the abdominal organs (liver, spleen, kidney, adrenal glands, mesentery and colon). The diagnosis was confirmed by histopathological examination. This is the first report of granulomatous colitis associated with feline xanthomatosis.
Perception of causes of malaria and treatment‐seeking behaviour of nursing mothers in a rural community
Authors: Ibidapo Comfort A.
Published: July 2005

Objective:  Maternal health care workers’ recognition of malaria, its transmission and treatment of children's fever at community level.

Design:  Randomised sampling of households with children of 0–5 years.

Setting:  Rural community in a forest zone.

Subjects:  Fifty‐five households at Ijegemo village, Ogun state, Nigeria were sampled and questionnaires administered to 200 mothers/care workers of children within the age group 0–5 years. Blood smears were obtained from finger pricks and level of parasitemia with malaria parasites determined for each child.

Main outcome measures:  Interactions with the women during the survey empowered them with accurate knowledge of malaria recognition, transmission and management of children's fever at the community level.

Results:  Forty per cent of the respondents did not know the exact cause of malaria, 20% attributed the cause to sunlight, 16.5% to mosquitoes, 12.5% to poor hygiene, 4% to palm oil intake, 4% to blood shortage and 6% to a hot body. Of respondents 85.5% identified stagnant water as breeding site of mosquitoes but could not correlate it with the occurrence of malaria fever. Herbal concoction was the first treatment action. Some of these herbs are listed in the text. Plasmodium falciparum alone was identified in all blood smears. Children at two to three years of age were recorded with the highest percentage (67.5%) of parasite‐positive cases with a mean value of 1237.04 ± 2113.19.

Conclusion:  This study highlights a critical need for targeting health messages towards poorly educated women in order to empower them with the knowledge and resources to recognise and manage their children's health problems.
The diabetes experiences of Aboriginal people living in a rural Canadian community
Authors: Barton Sylvia S. , Anderson Nancy , Thommasen Harvey V.
Published: July 2005

Objective:  To optimise participation with Aboriginal people by sharing experiences of living with the challenges of diabetes in rural south‐western Canada, and how these could be addressed.

Design:  Qualitative content analysis of semi‐structured and conversational interviews.

Setting:  Diabetes health services in the Bella Coola Valley, British Columbia, Canada.

Subjects:  Eight Nuxalk Nation participants, five women and three men, living with type 2 diabetes, were interviewed. Four of these participants, three women and one man, were engaged in six follow‐up conversational interviews.

Main outcome measures:  The descriptive research explored experiences of Nuxalk people living with the challenges of diabetes, and how these could inform diabetes health services in culturally specific ways.

Results:  Challenges included understanding the connections between (i) diabetes and western or traditional medicines; (ii) dietary changes, exercise and weight loss; (iii) how health professionals communicate and the relevance of what is said; (iv) having many life choices and the responsibility to choose; and (v) a belief in living day by day and an awareness of life cycles that may need to be broken.

Conclusion:  The study substantiated the fundamental necessity for diabetes health services to be inclusive of Aboriginal perspectives.
Endoscopic submucosal dissection for early gastric cancer
Authors: ONO Hiroyuki
Published: July 2005

Endoscopic mucosal resection (EMR) has been accepted as a treatment of early gastric cancer (EGC). The number of EMR procedures for EGC has been increasing because a patient's quality of life after EMR is superior to that after surgical gastrectomy. In Japan, most EMR have been performed using the strip biopsy method; however, in some cases we experienced local recurrences when multiple fragments had been resected by this method. Single‐fragment resection is preferable for correct histological diagnosis and a patient's prognosis. Recently, dramatic changes have occurred in the operational technique and design of the accessory apparatus. In 1996, we developed a special endoscopic knife, called the insulation‐tipped electrosurgical knife (IT knife), which consists of a conventional diathermic needle knife with a ceramic ball at the top to minimize the risk of perforation. This knife can cut submucosa safely and remove a lesion completely. We named this method endoscopic submucosal dissection (ESD). Using this procedure, 96% of the tumors (471/488) were completely resected in one piece. During the follow‐up period, there were no recurrent cases. One‐piece resection by ESD using the IT knife improves the quality of life and prognosis for patients with early gastric cancer.
Evaluation of the inhibitory effect of antisense oligodeoxynucleotides on the growth of hepatitis C‐associated hepatocellular carcinoma cells in vitro
Authors: AMIN Mona A , AWADEIN Mohamed R , GABR Hala
Published: July 2005

OBJECTIVE:  Hepatitis C virus (HCV) RNA is invariably detected in the serum and tumor tissue of anti‐HCV‐positive patients with hepatocellular carcinoma (HCC). The inflammation and cirrhosis caused by HCV could be the promoter for development of HCC or HCC could be the consequence of HCV infection independent of the effect of cirrhosis. The ability of the core protein of HCV to modulate gene transcription, cell proliferation and cell death by interacting with cellular genes that regulate cell growth and differentiation is involved in the pathogenesis of HCC. HCV NS3 protease is an attractive target for antiviral agent development because it is required for viral replication. Recent studies that constructed an in vitro model of HCC demonstrated that antisense oligodeoxynucleotides (AS‐ODN) interfered with NS3 translation in a dose‐dependent fashion and significantly inhibited protease activity. We studied the in vitro effect of AS‐ODN on the rate of growth of the HCC cells grown in culture associated with HCV.

METHODS:  Core biopsy was taken from 20 patients with HCC associated with HCV and each one was divided into two parts: group I to which antisense was added and group II which served as a control group. Comparison of cell viability between tubes with and without AS‐ODN was done using MTT assay, LDH assay, cell cycle analysis, trypan blue exclusion test and colony formation in soft agar.

RESULTS:  Colony formation in soft agar was inhibited in group I compared with the control group and the inhibition was highly significant (P < 0.01). The LDH concentration in culture supernatant and the trypan blue exclusion test, both reflecting cellular death, was higher in group I than group II and the difference was highly significant (P < 0.01). MTT assay showed a highly significant decrease in cell activation in group I than in group II (P < 0.01). The percentage of cells in the G0/G1 phase was higher in group I than in group II and the difference was significant (P = 0.04). There was an insignificant difference between both groups in the percentage of cells in S phase (P = 0.378). The inhibitory effect of AS‐ODNs on tumor cells in G2/M phase was highly significant compared with the control group (P < 0.01).

CONCLUSIONS:  AS‐ODN has a significant inhibitory effect on the growth of HCV‐associated HCC cells grown in fluid culture, and there is potential for the use of AS‐ODN as oncotherapy.
Inhibitory effects of CB1 and CB2 receptor agonists on responses of DRG neurons and dorsal horn neurons in neuropathic rats
Authors: Sagar Devi Rani , Kelly Sara , Millns Paul J. , O'Shaughnessey Celestine T. , Kendall David A. , Chapman Victoria
Published: July 2005

Cannabinoid 2 (CB2) receptor mediated antinociception and increased levels of spinal CB2 receptor mRNA are reported in neuropathic Sprague–Dawley rats. The aim of this study was to provide functional evidence for a role of peripheral, vs. spinal, CB2 and cannabinoid 1 (CB1) receptors in neuropathic rats. Effects of the CB2 receptor agonist, JWH‐133, and the CB1 receptor agonist, arachidonyl‐2‐chloroethylamide (ACEA), on primary afferent fibres were determined by calcium imaging studies of adult dorsal root ganglion (DRG) neurons taken from neuropathic and sham‐operated rats. Capsaicin (100 nm) increased [Ca2+]i in DRG neurons from sham and neuropathic rats. JWH‐133 (3 µm) or ACEA (1 µm) significantly (P < 0.001) attenuated capsaicin‐evoked calcium responses in DRG neurons in neuropathic and sham‐operated rats. The CB2 receptor antagonist, SR144528, (1 µm) significantly inhibited the effects of JWH‐133. Effects of ACEA were significantly inhibited by the CB1 receptor antagonist SR141716A (1 µm). In vivo experiments evaluated the effects of spinal administration of JWH‐133 (8–486 ng/50 µL) and ACEA (0.005–500 ng/50 µL) on mechanically evoked responses of neuropathic and sham‐operated rats. Spinal JWH‐133 attenuated mechanically evoked responses of spinal neurons in neuropathic, but not sham‐operated rats. These inhibitory effects were blocked by SR144528 (0.001 µg/50 µL). Spinal ACEA inhibited mechanically evoked responses of neuropathic and sham‐operated rats, these effects were blocked by SR141716A (0.01 µg/50 µL). Our data provide evidence for a functional role of CB2, as well as CB1 receptors on DRG neurons in sham and neuropathic rats. At the level of the spinal cord, CB2 receptors have inhibitory effects in neuropathic, but not sham‐operated rats suggesting that spinal CB2 may be an important analgesic target.