Persistence of 2-tridecanone on the leaves of seven vegetables.
Explore the source record for details and available documents.
SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
A wide range of pesticides used to control pests in vegetables have been determined in agricultural plant waste from beans, watermelons, and melons grown in greenhouses located in a predominantly agricultural area in Southeast Spain (Almería). Analysis of the pesticides was carried out by low-pressure gas chromatography (LP-GC) with mass spectrometry in tandem (MS-MS) mode, after extraction of the lyophilized samples with dichloromethane. The influence of the sample matrix on the analysis was avoided by use of matrix-matched standards. Linearity, detection limit ( LOD), quantitation limit ( LOQ), recovery, and precision for each pesticide were calculated. The most frequently encountered pesticides were endosulfan (>73% of the analyzed samples) and buprofezin (>55% of the samples), followed by cypermethrin, pirimifos-methyl, bifentrin, and chlorpyrifos (>30% of the samples). The pesticide found at the highest concentration level was endosulfan (223.33 mg kg(-1)) in a watermelon sample.
In watermelon, grafting of seedlings to rootstocks is necessary because watermelon roots are less viable than the rootstock. Moreover, commercially important watermelon varieties require disease-resistant rootstocks to reduce total watermelon yield losses due to infection with viruses such as cucumber green mottle mosaic virus (CGMMV). Therefore, we undertook to develop a CGMMV-resistant watermelon rootstock using a cDNA encoding the CGMMV coat protein gene (CGMMV-CP), and successfully transformed a watermelon rootstock named 'gongdae'. The transformation rate was as low as 0.1-0.3%, depending on the transformation method used (ordinary co-culture vs injection, respectively). However, watermelon transformation was reproducibly and reliably achieved using these two methods. Southern blot analysis confirmed that the CGMMV-CP gene was inserted into different locations in the genome either singly or multiple copies. Resistance testing against CGMMV showed that 10 plants among 140 T1 plants were resistant to CGMMV infection. This is the first report of the development by genetic engineering of watermelons resistant to CGMMV infection.
A normalized cDNA library was constructed using watermelon flesh mRNA from three distinct developmental time-points and was subtracted by hybridization with leaf cDNA. Random cDNA clones of the watermelon flesh subtraction library were sequenced from the 5' end in order to identify potentially informative genes associated with fruit setting, development, and ripening. One-thousand and forty-six 5'-end sequences (expressed sequence tags; ESTs) were assembled into 832 non-redundant sequences, designated as "EST-unigenes". Of these 832 "EST-unigenes", 254 ( approximately 30%) have no significant homology to sequences published so far for other plant species. Additionally, 168 "EST-unigenes" ( approximately 20%) correspond to genes with unknown function, whereas 410 "EST-unigenes" ( approximately 50%) correspond to genes with known function in other plant species. These "EST-unigenes" are mainly associated with metabolism, membrane transport, cytoskeleton synthesis and structure, cell wall formation and cell division, signal transduction, nucleic acid binding and transcription factors, defense and stress response, and secondary metabolism. This study provides the scientific community with novel genetic information for watermelon as well as an expanded pool of genes associated with fruit development in watermelon. These genes will be useful targets in future genetic and functional genomic studies of watermelon and its development.
We have studied the biological and molecular characteristics of a MNSV isolate collected in Spain (MNSV-Malpha5) and generated a full-length cDNA clone from which infectious RNA transcripts can be produced. The host range of MNSV-Malpha5 appeared to be limited to cucurbits and did not differ from that of MNSV-Dutch [4, 21]. However, differences were observed in the type of symptoms that both isolates could induce. A full-length cDNA of MNSV-Malpha5 was directly amplified by reverse-transcription polymerase chain reaction (RT-PCR) using a 5'-end primer anchoring a T7 RNA promoter sequence and a 3'-end primer, and cloned. Uncapped RNAs transcribed from this cDNA clone were infectious and caused symptoms indistinguishable from those caused by viral RNA when mechanically inoculated onto melon, cucumber or watermelon plants. The complete genome sequence of MNSV-Malpha5 was deduced from the full length cDNA clone. It is 4271 nt long and, similarly to MNSV-Dutch, consists of 5' and 3' untranslated regions (UTRs) and five open reading frames (ORFs) coding for 29, 89, 42 and two small 7 kDa proteins. One notable difference between MNSV-Malpha5 and other sequenced MNSV isolates was found, as for MNSV-Malpha5 the first of the two small ORFs, which are contiguous in the genome, terminates with a genuine stop codon, whereas for MNSV-Dutch and other sequenced MNSV isolates it terminates with an amber codon. This suggested that the putative p14 readthrough protein that could be expressed from the MNSV-Dutch and other MNSV genomes could not be expressed from the MNSV-Malpha5 genome. Also, the nucleotide and amino acid sequences comparisons showed a distant relationship of MNSV-Malpha5 with other known MNSV isolates.
Watermelon mosaic virus (WMV, Potyvirus) is a potyvirus with a worldwide distribution, mostly in temperate and mediterranean regions. According to the partial sequences that were available, WMV appeared to share high sequence similarity with Soybean mosaic virus (SMV), and it was almost considered as a strain of SMV in spite of its different and much broader host range. Like SMV, it was also related to legume-infecting potyviruses belonging to the " Bean common mosaic virus (BCMV) subgroup". In this paper we obtained the full-length sequence of WMV, and we confirmed that this virus is very closely related to SMV in most of its genome; however, there is evidence for an interspecific recombination in the P1 protein, as the P1 of WMV was 135 amino-acids longer than that of SMV, and the N-terminal half of the P1 showed no relation to SMV but was 85% identical to BCMV. This suggests that WMV has emerged through an ancestral recombination event, and supports the distinction of WMV and SMV as separate taxonomic units.
Zucchini yellow fleck virus (ZYFV, genus Potyvirus) infects cultivated or wild cucurbits in the Mediterranean basin and occasionally causes severe damage in crops. Biological and serological data tend to indicate that ZYFV is related to other cucurbit-infecting potyviruses, mainly papaya ringspot virus (PRSV) and Moroccan watermelon mosaic virus (MWMV). In order to establish unambiguously the taxonomic status of ZYFV, the sequence of the 3' part of the genome - encompassing the CP coding region - of two ZYFV strains originating from Italy and France was obtained and compared with other potyviruses. The results obtained indicate that ZYFV belongs to a distinct potyvirus species, related to but different from PRSV and MWMV.
PURPOSE: Seed bezoars in the rectum have been considered an uncommon cause of fecal impaction in adults. Although there have been several reports on sunflower seed bezoars, seed bezoars from the fruit of the prickly pear cactus and watermelon have received little notice. This study was designed to determine the frequency of fecal impaction by seed bezoars in the rectum and their clinical characteristics in adults. METHODS: A retrospective review of the medical records of patients hospitalized with the diagnosis of fecal impaction during a ten-year period. RESULTS: During the study period (January 1996 to December 2005), 55 patients were hospitalized at the Western Galilee Hospital, in northern Israel, with the diagnosis of fecal impaction. Phytobezoars were found in 30 patients (55 percent). The seed bezoars were composed of prickly pear seeds in 12 patients, watermelon seeds in 10 patients, sunflower seeds in 4 patients, popcorn kernels in 1 patient, and pomegranate seeds in 1 patient. The Jew:Arab ratio for seed bezoars was 7:23. Seventy-three patients had seedless fecal masses with a Jew:Arab ratio of 58:15. All 30 patients with bezoar underwent digital disimpaction under general anesthesia. Only 21 of 73 patients with seedless fecal masses were treated under general anesthesia. CONCLUSIONS: Seed bezoars found in the rectum were the most common cause of fecal impaction requiring hospitalization, probably to the result of the eating habits in the Middle East. The consumption of seeds with shell fragments or fruits containing many seeds (such as the prickly pear) should be accompanied by the awareness that large quantities may cause fecal impaction.
Watermelon mosaic virus (WMV) is a potyvirus with a worldwide distribution, but is mostly found in temperate and Mediterranean regions. The complete nucleotide (nt) sequence of a Pakistani isolate of WMV (WMV-Pk) was determined and compared with French isolate (WMV-Fr) and other closely related potyviruses. WMV-Pk showed overall identities of 94.4% (nt) and 96% (amino acid; aa) with the WMV-Fr. However, variability was observed in the 5' UTR and P1 region. Although sequence identities over most of the genome were well above 90% at both the nt and aa levels, reaching 99.6% (aa) in the CP and 100% (aa) in the 6K1 and 6K2, thereby suggesting that WMV-Pk and WMV-Fr are identical strains, but the sequence identities in the P1 region were only 80.6% (aa) and 82.8% (nt), while that in the 5' UTR was 82%. These differences may be due to different mutation phenomena of a common ancestor virus or mutations caused by different selection pressures in two different agro-ecological zones. The sequence of WMV-Pk is very close to that of Soybean mosaic virus (SMV) over most of the genome, except for the N-terminal region, which is subject to recombination between SMV and Peanut stripe virus (PSV)/Bean common mosaic virus (BCMV), as revealed by Simplot and phylogenetic analyses of N- and C-terminal P1, HC-Pro, and 5' UTR regions of the genome.
Explore the source record for details and available documents.
Watermelon cells after permeabilization in Tween 80 were immobilized by glutaraldehyde without any carrier. Cells immobilized by cross-linking demonstrated significantly lower aminopeptidase activities than untreated cells. Pectate and alginate hydrogels were used successfully for immobilization of watermelon cells which retained activities of some aminopeptidases. A simple and rapid procedure for determination of extracellular aminopeptidases was developed using a synthetic substrate. p-Nitroanilides of amino acids were used as substrates for the determination of the extracellular and intracellular enzymatic activities. The culture medium (without cells) was used for the identification and determination of extracellular enzyme activities, whereas intracellular activities were estimated from the cell suspension.
A simple, rapid and reproducible procedure for the identification and determination of extracellular saccharase from culture medium of watermelon cell suspension cultures is described. The culture medium (without cells) was used for the identification and determination of extracellular enzyme activity. Intracellular activity was estimated from the cell suspension. Watermelon cell suspension was permeabilized by Tween 80 and immobilized by glutaraldehyde. The highest saccharase activity was at pH 4.6 at a temperature of 50 degrees C. The hydrolysis of substrate was linear 5h after reaching 60% conversion. The cells had high saccharase activity and good stability, and in long-term storage they showed convenient physico-mechanical properties.
A plant pathogenic fungus, Colletotrichum lagenarium, causing watermelon anthracnose, was isolated from naturally infected leaves, stems, and fruits of watermelon. A bacterial strain, MET0908, showing a potent antifungal activity against C. lagenarium, was isolated from soil. An antifungal protein was purified by 30% ammonium sulfate saturation and concentrated using Centricon 10, DEAE-Sepharose(TM) Fast Flow column and Sephacryl S-100 gel filtration chromatography. The molecular weight of the purified protein was estimated as 40 kDa by SDS-PAGE. The purified protein was stable at 80 degrees C for 20 min and exhibited a broad spectrum of antifungal activity against various plant pathogenic fungi. Confocal microscopy image analysis and scanning electron microscopy showed that the protein acted on the cell wall of C. lagenarium. The purified antifungal protein exhibited beta-1,3-glucanase activity. The N-terminal amino acid sequence of the purified protein was determined as Ser-Lys-Ile-x-Ile-Asn-Ile-Asn-Ile-x-Gln-Ala-Pro-Ala-Pro-x-Ala. A search of the sequence with NCBI BLAST showed no significant homology with any known proteins, suggesting that the purified protein may be novel.
We developed two species-specific PCR assays for rapid and accurate detection of the pathogenic fungi Fusarium oxysporum f. sp. niveum and Mycosphaerella melonis in diseased plant tissues and soil. Based on differences in internal transcribed spacer (ITS) sequences of Fusarium spp. and Mycosphaerella spp., two pairs of species-specific primers, Fn-1/Fn-2 and Mn-1/Mn-2, were synthesized. After screening 24 isolates of F. oxysporum f. sp. niveum, 22 isolates of M. melonis, and 72 isolates from the Ascomycota, Basidiomycota, Deuteromycota, and Oomycota, the Fn-1/Fn-2 primers amplified only a single PCR band of approximately 320 bp from F. oxysporum f. sp.niveum, and the Mn-1/Mn-2 primers yielded a PCR product of approximately 420 bp from M. melonis. The detection sensitivity with primers Fn-1/Fn-2 and Mn-1/Mn-2 was 1fg of genomic DNA. Using ITS1/ITS4 as the first-round primers, combined with either Fn-1/Fn-2 and or Mn-1/Mn-2, two nested PCR procedures were developed, and the detection sensitivity increased 1000-fold to 1ag. The detection sensitivity for the soil pathogens was 100-microconidia/g soil. A duplex PCR method, combining primers Fn-1/Fn-2 and Mn-1/Mn-2, was used to detect F. oxysporum f. sp. niveum and M. melonis in plant tissues infected by the pathogens. Real-time fluorescent quantitative PCR assays were developed to detect and monitor the pathogens directly in soil samples. The PCR-based methods developed here could simplify both plant disease diagnosis and pathogen monitoring as well as guide plant disease management.
In vitro gene expression strategy was used for the production of polyclonal antiserum to the nucleocapsid protein (NP) of Groundnut bud necrosis virus (GBNV). The GBNV NP gene from cowpea isolate was cloned into 6x His-tagged UA cloning vector and expressed in Escherichia coli [M15] cells. The fusion protein was detected in insoluble fraction and was purified by using Ni-NTA agarose resin. The purified 6x His-fusion protein ( approximately 32 kDa) was used for immunisation to produce a high titre polyclonal antiserum. The antiserum to the NP of GBNV at 1:4000 dilution detected successfully natural infection of GBNV and Watermelon bud necrosis virus in a wide range of cucurbitaceous, leguminous and solanaceous hosts from different locations.
The genetic structure of the population of Watermelon mosaic virus (WMV) in Spain was analysed by the biological and molecular characterisation of isolates sampled from its main host plant, melon. The population was a highly homogeneous one, built of a single pathotype, and comprising isolates closely related genetically. There was indication of temporal replacement of genotypes, but not of spatial structure of the population. Analyses of nucleotide sequences in three genomic regions, that is, in the cistrons for the P1, cylindrical inclusion (CI) and capsid (CP) proteins, showed lower similar values of nucleotide diversity for the P1 than for the CI or CP cistrons. The CI protein and the CP were under tighter evolutionary constraints than the P1 protein. Also, for the CI and CP cistrons, but not for the P1 cistron, two groups of sequences, defining two genetic strains, were apparent. Thus, different genomic regions of WMV show different evolutionary dynamics. Interestingly, for the CI and CP cistrons, sequences were clustered into two regions of the sequence space, defining the two strains above, and no intermediary sequences were identified. Recombinant isolates were found, accounting for at least 7% of the population. These recombinants presented two interesting features: (i) crossover points were detected between the analysed regions in the CI and CP cistrons, but not between those in the P1 and CI cistrons, (ii) crossover points were not observed within the analysed coding regions for the P1, CI or CP proteins. This indicates strong selection against isolates with recombinant proteins, even when originated from closely related strains. Hence, data indicate that genotypes of WMV, generated by mutation or recombination, outside of acceptable, discrete, regions in the evolutionary space, are eliminated from the virus population by negative selection.
Drought-tolerant wild watermelon accumulates high levels of citrulline in the leaves in response to drought conditions. In this work, the hydroxyl radical-scavenging activity of citrulline was investigated in vitro. The second-order rate constant for the reaction between citrulline and hydroxyl radicals was found to be 3.9x10(9) M(-1) s(-1), demonstrating that citrulline is one of the most efficient scavengers among compatible solutes examined so far. Moreover, citrulline effectively protected DNA and an enzyme from oxidative injuries. Liquid chromatography-mass spectrometry analysis revealed that at least four major products were formed by the reaction between citrulline and hydroxyl radicals. Activities of metabolic enzymes were not inhibited by up to 600 mM citrulline, indicating that citrulline does not interfere with cellular metabolism. We reasoned, from these results, that citrulline contributes to oxidative stress tolerance under drought conditions as a novel hydroxyl radical scavenger.
Didymella bryoniae (anamorph Phoma cucurbitacearum) is an ascomycete that causes gummy stem blight, a foliar disease that occurs on cucurbits in greenhouses and fields throughout the world. In a previous study using RAPD analysis, little genetic diversity was found among isolates of D. bryoniae from New York and South Carolina, USA. Here we report the use of amplified fragment length polymorphism (AFLP) analysis to assess the genetic variation within a worldwide collection of D. bryoniae, 102 field and greenhouse isolates from ten states in the USA (California, Delaware, Florida, Georgia, Indiana, Maryland, Michigan, Oklahoma, South Carolina, and Texas) and seven other countries (Australia, Canada, China, Greece, Israel, Sweden, and The Netherlands) were examined. Seven different AFLP primer-pair combinations generated 450 bands, of which 134 were polymorphic (30%). Using cluster analysis, two groups and a total of seven subgroups were delineated. Representative isolates varied in their virulence on muskmelon and watermelon seedlings, but the degree of virulence was not strongly associated with AFLP groupings. However, isolates from the northern USA grouped separately from isolates originating from the southern USA.