bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ontogenetic and spatial variation in the diet of hake (Merluccius merluccius) in the Bay of Biscay and the Celtic Sea
Authors: Mahe K. , Amara R. , Bryckaert T. , Kacher M. , Brylinski J. M. 
Published: July 2007

Abstract
Mahe, K., Amara, R., Bryckaert, T., Kacher, M., and Brylinski, J. M. 2007. Ontogenetic and spatial variation in the diet of hake (Merluccius merluccius) in the Bay of Biscay and the Celtic Sea. – ICES Journal of Marine Science, 64: 1210–1219. Analysis of the diet of trawl-caught hake (Merluccius merluccius) from three locations in the Bay of Biscay and the Celtic Sea in autumn 2001 showed that small hake fed almost exclusively on crustaceans (mainly euphausiids), but that there was a significant shift towards a fully piscivorous diet in hake >23 cm. A change in fish prey was also size-dependent, because smaller hake (<30 cm) preyed on small pelagic fish (3–12 cm), such as horse mackerel, anchovy, and pilchard, and larger hake on larger demersal prey (12–23 cm), such as blue whiting. There was a significant positive relationship between hake and fish prey length. In terms of fish prey selectivity, hake exhibited particular preference for small pelagic prey (anchovy, pilchard, and argentine) and for other hake. The diet did not generally reflect fish prey availability. Although horse mackerel and blue whiting were the two most abundant fish prey species in the environment, they were not positively selected by hake. Cannibalism accounted for a non-negligible part of the diet and was observed mainly in large hake (>30 cm). For all sizes analysed, conspecifics constituted 19.2%W of the diet and the frequency of occurrence of hake in the stomachs was 10.53%. Most hake prey were 0-group juveniles (<20 cm). Hake cannibalism appeared to be influenced mainly by the abundance of juveniles and the overlap between distribution patterns of juveniles and adults.
Nested-PCR Detection and Sequence Confirmation of ‘Candidatus Liberibacter asiaticus’ from Murraya paniculata in Guangdong, China
Authors: Deng X. , Zhou G. , Li H. , Chen J. , Civerolo E. L. 
Published: July 2007

Murraya paniculata (orange jasmine) is a popular ornamental rutaceaous plant and is known to be a preferred host for the Asian citrus psyllid, Diaphorina citri (Kuwayana), the primary vector of ‘Candidatus Liberibacter spp.’ that causes citrus Huanglongbing (HLB). HLB is a highly destructive citrus disease worldwide. However, the presence of ‘Ca. Liberibacter spp.’ in M. paniculata remains uncertain (2). Clarification of M. paniculata as a host of ‘Ca. Liberibacter spp.’ has direct impact on HLB control programs. During June of 2006, we identified three M. paniculata trees near a mandarin orchard affected by HLB in Luoding City and two trees from Guangzhou City, Guangdong Province, People's Republic of China. All trees had leaves showing yellowing and mottling symptoms characteristic of HLB. Both symptomatic and asymptomatic leaves were collected. DNA was extracted using the CTAB (cetyltrimethylammoniumbromide) method and assayed by nested-PCR. The general bacterial 16S rDNA primer set fDl/rD1 (3) was used for the first round of amplification. Amplification was conducted as previously described (1), and 2 μl of PCR reaction product were used for a second round of amplification using the same procedure but with 35 PCR cycles with primer set OI1/OI2c (3,4). After agarose gel electrophoresis and staining with ethidium bromide, a 1.1-kb DNA band was unambiguously associated with symptomatic but not asymptomatic leaf samples. Nonnested-PCR using primer set OI1/OI2c alone did not yield a target DNA band or yielded a very weak DNA band. XbaI digestion of the nested-PCR DNA product yielded two fragments, 520 and 640 bp long, characteristic of ‘Ca. L. asiaticus’. PCR amplicons were sequenced and were 1,095 bp long. This sequence shared >98% similarity to sequences of ‘Ca. L. asiaticus’ in the GenBank database. We observed that nested-PCR is necessary for consistent amplification of DNA from ‘Ca. L. asiaticus’ from M. paniculata. We excluded the possible nonspecific amplification associated with nested-PCR by XbaI restriction enzyme digestion and by nucleotide sequence analysis. Our data indicate that M. paniculata is a host of ‘Ca. L. asiaticus’ but the bacterial titer might be low. References: (1) X. Deng et al. Online publication. doi:10.1094/PHP-2007-0419-01-BR. Plant Health Progress, 2007. (2) M. Garnier and J. Bove. Huanglongbing (Greening). Page 46 in: Compendium of Citrus Diseases. 2nd ed. L. W. Timmer et al., eds. The American Phytopathological Society, St. Paul, MN, 2000. (3) S. Jagoueix et al. Int. J. Syst. Bacteriol. 44:379, 1994. (4) S. Jagoueix et al. Mol. Cell. Probes 10:43, 1996.
First Report of Citrus leaf blotch virus on Kumquat in Italy
Authors: Guardo M. , Sorrentino G. , Marletta T. , Caruso A. 
Published: July 2007

During the spring of 2006, nurserymen reported observations of the bud union disorder of ‘Nagami’ kumquat scions propagated on Troyer citrange rootstock to the CRA–Istituto Sperimentale per l'Agrumicoltura. These plants showed reduced canopy volume and new shoots below graft points 6 months after propagation; the bud union was brittle and broke down easily after 1 year. After tests excluded common citrus viruses and viroids that might cause the incompatibility (e.g., Citrus tristeza virus, Citrus psorosis virus, Citrus exocortis viroid, and Hop stunt viroid), we tested for Citrus leaf blotch virus (CLBV), a virus previously associated with a bud union crease in kumquat (2). Leaves were collected from 100 2-year-old kumquat plants from a nursery near Messina (Sicily [Italy]); 50 were grafted on sour orange rootstock (asymptomatic) and 50 were grafted on Troyer citrange rootstock (symptomatic). Total RNA was extracted using Qiagen RNeasy Plant Mini Kit (Qiagen S.P.A. Milan, Italy). Primers previously reported (1,2) and designed from a published CLBV sequence (Genbank Accession No. AJ318061) were used in reverse transcription (RT)-PCR assays to amplify the RNA-dependent RNA polymerase gene (sense primer KU 27, 5′-GATGCAAGCCAGGATGAATAC-3′, genomic positions 5321–5340 and anti-sense primer KU 15, 5′-CAGACACTCCAAGACCTTTCC-3′, genomic positions 5776–5756) and the coat protein gene (sense primer KU18, 5′-TTAAGATTACAGACACGAAGG-3′ genomic positions 7686–7706 and anti-sense primer KU 19 5′-CTGTTTTTGAATTTTGCTCG-3′, genomic positions 8123–8104). All kumquat samples yielded amplicons of the expected size (456 and 438 bp). No amplicons were obtained from healthy plants. Amplicons for each gene were cloned into the pGEM-T Easy Vector (Promega Italy, Milan), and four clones for each plasmid DNA were sequenced in both directions. Consensus sequences of the two genes (Genbank Accession Nos. EF203229 and EF203230) had 96 and 97% nucleotide sequence identity, respectively, and both had 99% amino acid identity with the previously reported CLBV sequence (Genbank Accession No. AJ318061). Approximately 400,000 ornamental kumquats are produced annually in Italy. CLBV infection can cause serious production losses because of the decline associated with bud union disorders grafted onto trifoliate orange and trifoliate-derived rootstocks. References: (1) L. Galipienso et al. Eur. J. Plant Pathol. 110:175, 2004. (2) M. C. Vives et al. Virology 287:225, 2001.
First Report of a Phytoplasma Affecting Tomato in Poland
Authors: Pospieszny H. , Krawczyk K. , Kamasa J. , Petrzik K. 
Published: July 2007

During 2006, two tomato plants exhibiting dwarfing, twisting of shoots and leaves, and virescence and phyllody of flowers were observed in a greenhouse in western Poland. Total genomic DNA was extracted from approximately 3.5 g of leaf midribs and petioles using the modified cetyltrimethylammoniumbromide (CTAB) buffer method (3). Direct PCR was done with universal phytoplasma primers P1/P7 for amplification of ribosomal 16S rDNA. The PCR product (1.8 kb) was diluted 1:30 with sterile distilled water and used as DNA template for nested PCR with primers R16F2n/R16R2 (1). The final product was an expected 1.2-kb rDNA fragment amplified from infected tomato tissues. The DNA extracted from a Vinca sp. infected with phytoplasma of 16SrI-B subgroup and from a healthy tomato plant were used as positive and negative assay controls, respectively. Restriction fragment length polymorphism analysis of the final PCR product (1.2 kb) using enzymes MseI, KpnI, AluI, HhaI, HpaII, RsaI, TaqI, and TruI (1) indicated that phytoplasma from the tomato belonged to the subgroup 16SrI-C (1,2). The sequence obtained from the final PCR product (746 bp) was deposited in the GenBank database under accession number EF164961. Multiple sequence alignments with sequences of phytoplasma available from GenBank were performed using ClustalW software. The analysis revealed that the Polish isolate was co-identical (100%) to two phytoplasma sequences (GenBank Accession Nos. AY839617 and DQ078304) that belong to 16SrI-C subgroup. To our knowledge, this is the first report of a phytoplasma affecting tomato plant in Poland. References: (1) I.-M. Lee et al. Inst. J. Syst. Bacteriol. 48:1153, 1998. (2) I.-M. Lee et al. Cell-wall free bacteria. Page 283 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et a.l, eds. The American Phytopathology Society, 2001. (3) A. C. Padovan et al. Austral. J. Grape Wine Res. 1:25, 1995.
Squash vein yellowing virus Identified in Watermelon (Citrullus lanatus) in Indiana
Authors: Egel D. S. , Adkins S. 
Published: July 2007

During September 2006, moderate vine decline symptoms including vine collapse and wilt and root rot were observed on numerous watermelon plants growing in a commercial field in Sullivan County, Indiana. No symptoms were observed on the fruit. Six plants displaying typical vine decline symptoms were collected and assayed for potyvirus infection and subsequently for Squash vein yellowing virus (SqVYV) and Papaya ringspot virus type W (PRSV-W). SqVYV is a whitefly-transmitted member of the Potyviridae, recently shown to cause watermelon vine decline in Florida (1,4). Plants infected with SqVYV in Florida are also frequently infected with PRSV-W, although SqVYV is sufficient for watermelon vine decline. The six field samples harbored one or more potyviruses as determined by ELISA (Agdia, Elkhart, IN). Mechanical inoculation of squash (Cucurbita pepo) and watermelon with sap from three of the field samples induced mosaic symptoms in both that are typical of potyviruses. Vein yellowing in squash and plant death in watermelon typical of SqVYV (1) later developed in plants inoculated with one field sample. A coat protein gene fragment was amplified by reverse transcription (RT)-PCR with SqVYV primers (1) from total RNA of five of the six field samples and also from the symptomatic, inoculated plants. Nucleotide and deduced amino acid sequences of a 957-bp region of the RT-PCR product (primer sequences deleted prior to analysis) were 100% identical to SqVYV (GenBank accession No. DQ812125). PRSV-W also was identified in two of the five SqVYV-infected field samples by ELISA (Agdia) and by sequence analysis of a 3′ genome fragment amplified by RT-PCR with previously described degenerate potyvirus primers (3). No evidence for infection by other potyviruses was obtained. To our knowledge, this is the first report of SqVYV in Indiana and the first report of the virus anywhere outside of Florida. The whitefly (Bemisia tabaci, B strain) vector of SqVYV is relatively uncommon in Indiana and the cold winter temperatures make it unlikely that any SqVYV-infected watermelon vines or whiteflies will overseason, necessitating reintroductions of virus and vector each season. We feel that the moderate and restricted occurrence of SqVYV in Indiana observed in September 2006 should pose little or no threat to commercial watermelon production in Indiana and should not cause growers to alter their growing practices. The occurrence of SqVYV in Indiana does not appear to explain the similar symptoms of mature watermelon vine decline (MWVD) that has been observed in Indiana since the 1980s. In contrast with the insect vectored SqVYV, MWVD seems to be caused by a soilborne biological agent (2). References: (1) S. Adkins et al. Phytopathology 97:145, 2007. (2) D. S. Egel et al. Online publication. doi:10.1094/PHP-2000-1227-01-HN. Plant Health Progress, 2000. (3) A. Gibbs and A. Mackenzie. J. Virol. Methods 63:9, 1997. (4) P. Roberts et al. Citrus Veg. Mag. December 12, 2004.
Shoot Blight Caused by Diplodia pinea on Afghan and Austrian Pines in Texas
Authors: Ong K. , Hill S. , Smith D. R. , Stanosz G. R. 
Published: July 2007

Shoot blight was observed on ornamental Afghan (Pinus eldarica) and Austrian pines (P. nigra) at several sites in metropolitan Dallas, TX in the summer of 2005. Shoots were stunted, cankered, often resinous, sometimes curled or crooked at the tips, and bore brown needles that often had been killed before full elongation. Pycnidia on necrotic needles, stems, and cones of each host species yielded conidia characteristic of the fungus Diplodia pinea. Individual conidia and hyphal tip transfers produced pure cultures confirmed as D. pinea using a species-specific PCR assay (1), which allows differentiation from the similar pine shoot blight pathogen D. scrobiculata. Five isolates (three from Afghan pine and two from Austrian pine) were tested for pathogenicity by inoculation of potted 1-year-old Afghan pine seedlings obtained from the Texas Forest Service Nursery. Elongating terminal shoots were wounded by removing a needle pair approximately 2 cm below the shoot apex. A 4-mm-diameter plug cut from an actively growing culture on water agar (WA) was placed fungus side down on the wound. Noncolonized WA plugs were placed on similarly wounded control seedlings. Nonwounded control seedlings also were used. Parafilm was wrapped around the shoots to hold the agar plugs in place and was removed 2 weeks later. Each treatment was applied to four seedlings. Five weeks after inoculation, 9 of the 20 inoculated seedlings (including at least one inoculated with each isolate) exhibited dieback of shoot tips. One wounded control seedling exhibited slight tip dieback, no other nonwounded or wounded control seedlings developed symptoms. Segments of shoots were harvested, surface disinfested, and incubated on WA to determine the presence of the pathogen. The pathogen was reisolated from 11 of the 20 inoculated seedlings but not from any control seedlings. To our knowledge, this is the first report of D. pinea as a cause of shoot blight of Afghan pine and the first substantiated report of the occurrence of D. pinea in Texas. Although widely distributed in much of eastern North America, reports of the presence of D. pinea in the other southern gulf coast states of Alabama, Louisiana, and Mississippi, as well as the western states of Colorado, New Mexico, and Utah, are lacking. Reference: (1) D. R. Smith and G. R. Stanosz. Plant Dis. 90:307, 2006.
First Report of Soybean Rust Caused by Phakopsora pachyrhizi in Ghana
Authors: Bandyopadhyay R. , Ojiambo P. S. , Twizeyimana M. , Asafo-Adjei B. , Frederick R. D. , Pedley K. F. , Stone C. L. , Hartman G. L. 
Published: July 2007

Nigeria is the only country in West Africa where soybean rust, caused by Phakopsora pachyrhizi, has been officially reported (1). During a disease survey in Ghana during October 2006, soybean (Glycine max) leaves with rust symptoms (tan, angular lesions with erumpent sori exuding urediniospores) were observed in 11 fields in the following districts: Kassena Nankana in the Upper East Region; East Gonja, Central Gonja, and Tolon-Kumbungu in the Northern Region; and Ejisu-Juabeng in the Ashanti Region. Disease incidence in these fields ranged from 50 to 100% and disease severity ranged between 3 and 40% of the leaf area on infected plants. Urediniospores were hyaline, minutely echinulate, and 23 to 31 × 14 to 18 μm. Within a week of collection, leaf samples were sent to the USDA-ARS Foreign Disease-Weed Science Research Unit for verification of pathogen identity. DNA was extracted from leaf pieces containing sori with the Qiagen DNeasy Plant Mini kit (Valencia, CA), and all 11 field samples amplified in a real-time fluorescent PCR with the P. pachyrhizi-specific primers Ppm1 and Ppa2 (2). Sequence alignment of the internal transcribed spacer (ITS) region 2 further confirmed the identification as P. pachyrhizi (2). Infected leaves from three fields were separately washed in sterile water to collect urediniospores that were used to separately inoculate three detached leaves (for each isolate) of susceptible cultivar TGx 1485-1D (3). The abaxial surface of detached leaves was sprayed with 400 μl of spore suspension (1 × 106 spores per ml). A single leaf piece was placed in a 9-cm-diameter petri dish with adaxial side appressed on 1% technical agar amended with 10 μg/ml of kinetin. Lactic acid (1.5 ml/liter) and benomyl (12.5 mg/liter) were added to the agar medium to inhibit growth of saprophytic fungi and bacteria. Petri dishes were incubated at 20°C with a 12-h light/12-h dark cycle. Lesions on inoculated leaves developed 5 to 6 days after inoculation (DAI), and pustules (105 to 120 μm) formed 7 to 8 DAI and erupted 3 days later exuding columns of urediniospores similar in size to the initially collected isolates. Inoculating another set of detached leaves with a spore suspension (1 × 106 spores per ml) from the first set of detached leaves resulted in typical rust symptoms. The PCR assay, alignment of ITS region 2, morphological characters of the isolates, and pathogenicity tests demonstrate that P. pachyrhizi occurs in Ghana. To our knowledge, this is the first report of P. pachyrhizi in Ghana. References: (1) O. A. Akinsanmi et al. Plant Dis. 85:97, 2001. (2) R. D. Frederick et al. Phytopathology 92:217, 2002. (3) M. Twizeyimana et al. Online publication. http://www.plantmanagementnetwork.org/ infocenter/topic/soybeanrust/2006/posters/41.asp. Plant Management Network, 2006.
First Report of Tomato torrado virus in Tomato in the Canary Islands, Spain
Authors: Alfaro-Fernández A. , Córdoba-Sellés C. , Cebrián M. C. , Sánchez-Navarro J. A. , Espino A. , Martín R. , Jordá C. 
Published: July 2007

In 2003, greenhouse-grown tomato crops (Lycopersicon esculentum Mill.) in the Canary Islands (Spain) were observed showing an initial yellowing in defined areas at the base of the leaflet that later developed into necrotic spots or an extensive necrotic area progressing from the base to tip. Fruits were also affected, showing necrotic areas and often developing cracking. Generally, the plants that were affected seemed to be burnt, their growth was reduced, and the production level was seriously damaged. Similar symptoms have been observed in Murcia (Spain) since 2001, which have been recently associated with Tomato torrado virus (ToTV) infection (2). Twenty-two tomato samples showing “torrado disease” symptoms were collected from different greenhouses between 2003 and 2006 in Las Palmas (Canary Islands, Spain). To verify the identity of the disease, double-antibody sandwich (DAS)-ELISA was performed on leaf and fruit extracts of symptomatic plants using polyclonal antibodies specific to Potato virus Y (PVY), Tomato mosaic virus (ToMV), Tomato spotted wilt virus (TSWV) (Loewe Biochemica, Sauerlach, Germany), and Pepino mosaic virus (PepMV) (DSMZ, Braunschweig, Germany). Total RNA was extracted from the 22 tomato samples with the RNAwiz Extraction kit (Ambion, Huntingdon, United Kingdom) and tested using one-step reverse-transcription (RT)-PCR with the SuperScript Platinum Taq kit (Invitrogen Life Technologies, Barcelona, Spain) with primers specific to PepMV (1) and ToTV (2). All analyses included healthy tomato plants as negative controls. Five of the twenty-two tomato samples were positive for PepMV and negative for the other viruses tested by serological analysis. However, all 22 samples were positive in RT-PCR performed with the primers specific to ToTV segment RNA2. The RT-PCR assay to detect ToTV produced an amplicon of the expected size (580 bp). No amplification product was observed when healthy plants or a water control were used as a template in the RT-PCR reaction. The ToTV RT-PCR product was purified (High Pure PCR Product Purification kit, Roche Diagnostics, Mannheim, Germany) and sequenced. BLAST analysis of one sequence (GenBank Accession No. EF436286) showed 99% identity to ToTV RNA2 sequence (GenBank Accession No. DQ388880). To our knowledge, this is the first report of ToTV in the Canary Islands. References: (1) I. Pagán et al. Phytopathology 96:274, 2006. (2) M. Verbeek et al. Online Publication. doi:10.1007/s00705-006-0917-6. Arch. Virol., 2007.
The impact of climate change on the physical characteristics of the larger lakes in the English Lake District
Authors: GEORGE GLEN , HURLEY MARGARET , HEWITT DIANE 
Published: July 2007

Summary1. The larger lakes of the English Lake District have been the subject of intensive scientific study for more than 60 years. Year‐to‐year variations in the weather have recently been shown to have a major effect on their physical characteristics. The area is mild but very wet and the dynamics of the lakes are strongly influenced by the movement of weather systems across the Atlantic.2. Here, we combine the results of long‐term measurements and the projections from a Regional Climate Model (RCM) to assess the potential impact of climate change on the surface temperature and residence times of the lakes.3. The RCM outputs used were produced by the U.K. Hadley Centre and are based on the IPCC ‘A2’ scenario for the emission of greenhouse gases. These suggest that winters in the area will be very much milder and wetter by the 2050s and that there will be a pronounced reduction in the summer rainfall.4. An analysis of the meteorological data acquired between 1940 and 2000 shows that there have been progressive increases in the winter air temperature and in the rainfall which are correlated with the long‐term change in the North Atlantic Oscillation. The trends reported during the summer were less pronounced and were correlated with the increased frequency of anticyclonic days and a decrease in the frequency of westerly days in the British Isles.5. A simple model of the year‐to‐year variations in surface temperatures showed that the highest winter temperatures were recorded in the deeper lakes and the highest summer temperatures in the lakes with the shallowest thermoclines. When this model was used to predict the surface temperatures of the lakes in the 2050s, the greatest winter increase (+1.08 °C) was observed in the shallowest lake and the greatest summer increase (+2.18 °C) in the lake with the shallowest thermocline.6. The model used to estimate the seasonal variation in the residence time of the lakes showed that the most pronounced variations were recorded in lakes with a short residence time. Average winter residence times ranged from a minimum of 10 days to a maximum of 436 days and average summer values from a minimum of 23 days to a maximum of 215 days. When this model was used to predict the residence time of the lakes in the 2050s, the greatest winter decrease (−20%) was observed in the smallest lake and the greatest summer increase (+92%) in the lake with the shortest residence time.7. The results are discussed in relation to trends reported elsewhere in Europe and the impact of changes in the atmospheric circulation on the dynamics of the lakes. The most serious limnological effects were those projected for the summer and included a general increase in the stability of the lakes and a decrease in the flushing rate of the lakes with short residence times.