Papers by Ayyamperumal Jeyaprakash
Plant Health Progress, 2015
Zenodo (CERN European Organization for Nuclear Research), Oct 1, 1978
Indian Journal of Plant Protection, 1980
The survey of plant parasitic nematodes associated with grapes var. Anab-e-Shahi and Thompson See... more The survey of plant parasitic nematodes associated with grapes var. Anab-e-Shahi and Thompson Seedless in several vineyards of Hyderabad revealed that the reniform nematode. Rotylenchulus reniformis occurred in high popuiation in the samples (44 to 5275 nematodes/250 ml of soil). The frequency of distribution of R. reniformis was 98 percent and the population density in in comparison with other plant parasitic nematodes was 89 percent. It was concluded that R. reniformis was a widespread and predominent nematode parasite of grapes at Hyderabad
Nematropica, Jun 1, 2006
Belonolaimus longicaudatus has been reported as a complex species because of its variations in mo... more Belonolaimus longicaudatus has been reported as a complex species because of its variations in morphology and pathogenicity among different isolates. However there is no information about genetic characteristics of B. longicaudatus among different populations coupled with detailed morphological characteristics. Our objectives were to determine the intraspecific variation based on morphology and ITS1 DNA sequence among isolates collected from different geographical locations and host crops. Five isolates compared by all criteria were HA-potato, Hastings, FL; GV-bermudagrass, Gainesville, FL; LA-citrus, Lake Alfred, FL; GA-cotton, Tifton, GA; and NC-corn, Scotland County, NC. Two additional isolates compared with these five isolates with respect to ITS1 DNA sequence were NE-corn, Columbus, NE, and TX-bermudagrass, Poteet, TX. The ITS1 DNA sequence previously reported for South Carolina (SC) isolate (GenBank accession #U89696) was included for sequence comparison. Females of the LA and NC isolates were longer in body length and the LA isolate had a longer stylet compared with the other isolates (P = 0.05). The stylet knobs of the NC and LA isolates were typically teardrop or kidney-shaped, whereas the GA isolate was typically oval. The vaginal pieces of the LA isolate were the most prominent and clearly recognized among all isolates, but that of NC isolate was weakly developed and not clearly recognized. The lengths of the ITS1 region were similar, 468 bp for all isolates, excepting the TX isolate which had a length of 428 bp. For phylogenetic analysis, maximum parsimony, neighbor-joining, and maximum likelihood methods were used and phylogenetic trees were constructed. All three trees supported that the NE, SC, and TX isolates were clearly different from the FL (GV, HA, LA), GA, and NC isolates. The TX isolate seemed to have diverged from the group of FL, GA, and NC isolates, which was supported by a 100 bootstrap value.
Experimental Parasitology, Jun 1, 1986
Comparisons of chemotactic behavior from monoxenic and axenic culture. Experimental Parasitology ... more Comparisons of chemotactic behavior from monoxenic and axenic culture. Experimental Parasitology 61, 369-372. Significant differences in chemotactic response of Caenorhabditis elegans were demonstrated for nematodes from monoxenic culture as compared to nematodes from axenic culture. These results support those of a previous study in which large differences in growth, development, behavior, and longevity were shown for C. elegans in comparative assays of the monoxenic and axenic regimes.
Nematropica, Jun 1, 2006
Standard polymerase chain reaction (PCR) and high-fidelity PCR procedures were compared for ampli... more Standard polymerase chain reaction (PCR) and high-fidelity PCR procedures were compared for amplifying DNA sequences from five root-knot nematode species. High-fidelity PCR was found to be at least four orders of magnitude more efficient than standard PCR. High-fidelity PCR was used to amplify mitochondrial DNA sequences located between the cytochome oxidase subunit II (COII) and 16S rRNA genes from the following root-knot nematode species; Meloidogyne mayaguensis (0.7 kb), M. floridensis (1.1 kb), M. arenaria (1.1 kb), M. incognita (1.5 kb), and M. javanica (1.6 kb). This region includes the non-coding "control" region, which is also referred to as AT-rich region and tRNA-His gene. The high-fidelity PCR products were cloned and sequenced. The COII 3' partial, tRNA-His, and 16S rRNA 5' partial sequences were found to display few nucleotide differences, but the AT-rich region displayed extensive nucleotide and length variations in all five species; M. mayaguensis (167 bp), M. arenaria (573 bp), M. floridensis (603 bp), M. incognita (963 bp), and M. javanica (1110 bp). A stem and loop structure, which has been characterized from insects and other higher organisms, was detected in a conserved block of AT-rich sequences from M. floridensis , M. arenaria , M. incognita , and M. javanica. Similar stem and loop structures were also detected from the AT-rich sequences previously reported from Caenorhabditis elegans and Ascaris suum and compared to the M. floridensis stem and loop structure. Even though the high-fidelity PCR products amplified from M. floridensis and M. arenaria were about the same size (1.1 kb), their AT-rich sequences were found to contain nucleotide differences at several locations. Hence, digesting the 1.1 kb high-fidelity PCR products from these species with the restriction enzyme Ssp I produced two distinct banding patterns that distinguished M. floridensis from M. arenaria .
PubMed, Oct 1, 1986
Caenorhabditis elegans and Panagrellus redivivus were investigated for surface carbohydrates usin... more Caenorhabditis elegans and Panagrellus redivivus were investigated for surface carbohydrates using fluorescent-labelled and ferritin-labelled lectins. Rhodamine-labelled Concanavalin A was specifically located in the cephalic region of both species. Rhodamine-labelled wheat germ agglutinin was located over the entire cuticle of P. redivivus but was absent on C. elegans. Rhodamine-labelled peanut agglutinin and Limax flavus agglutinin did not label nematodes of either species. Galactose and sialic acid were not detected on either species, whereas mannose-glucose residues were specifically localized in the head areas of both species. No detectable N-acetylglucosamine occurred on C. elegans, but it was evenly distributed over the cuticle surface of P. redivivus.
PubMed, Jul 1, 1985
The endoparasitic nematophagous fungus Meria coniospora reduced root-knot nematode galling on tom... more The endoparasitic nematophagous fungus Meria coniospora reduced root-knot nematode galling on tomatoes in greenhouse pot trials. The fungus was introduced to pots by addition of conidia at several inoculum levels directly to the soil or addition of nematodes infected with M. coniospora to the soil; both methods reduced root galling by root-knot nematodes. These studies represent a part of a recently initiated effort to evaluate the potential of endoparasitic nematophagous fungi for biocontrol of nematodes.
World Academy of Science, Engineering and Technology, International Journal of Bioengineering and Life Sciences, Oct 19, 2017
Journal of Invertebrate Pathology, Mar 1, 2002
A new microsporidian species is described from the predatory mite Metaseiulus (formerly Typhlodro... more A new microsporidian species is described from the predatory mite Metaseiulus (formerly Typhlodromus or Galendromus) occidentalis (Nesbitt) (Acari, Phytoseiidae). The ultrastructure of this new species is presented together with the first molecular characterization for a microsporidium of mites. All stages of this new microsporidium are haplokaryotic and develop in direct contact with the host-cell cytoplasm. Sporogony is disporoblastic and spores are formed in eggs, immature stages, and adults of M. occidentalis. There are two morphological classes of spores, one with a short polar filament (3-5 coils) that measured 2:53 Â 1:68 lm and one with a longer polar filament (8-9 coils) that measured 3:14 Â 1:77 lm. Horizontal transmission of this new species occurs by cannibalism of eggs and other stages and perhaps involves the spores with the long polar filament. Spores with the short polar filament may play a role in autoinfection and vertical (transovarial) transmission that is highly efficient in transferring the microsporidium from adults to progeny. Analysis of the small subunit ribosomal DNA indicated that this species from M. occidentalis is most closely related to the Nosema/Vairimorpha clade of microsporidia. A conflict between the morphological and molecular data is discussed. The species is compared to previously described microsporidia of arachnids resulting in creation of Oligosporidium occidentalis n. sp. in the family Unikaryonidae.
Applied and Environmental Microbiology, 1985
The conidia of the endoparasitic fungus Meria coniospora ( Deuteromycetes ) had different pattern... more The conidia of the endoparasitic fungus Meria coniospora ( Deuteromycetes ) had different patterns of adhesion to the cuticles of the several nematode species tested; adhesion in some species was only to the head and tail regions, on others over the entire cuticle, whereas on others there was a complete lack of adhesion. After adhesion, the fungus usually infected the nematode. However, adhesion to third-stage larvae of five animal parasitic nematodes, all of which carry the cast cuticle from the previous molt, did not result in infection. M. coniospora infected animal parasitic nematodes when this protective sheath was removed. Seven preparations of sialic acid ( N -acetylneuraminic acid) gave three types of response in adhesion-infection of nematodes: (i) a significant reduction in conidial adhesions; (ii) no interference with adhesion, but a 10-day delay in infection; and (iii) a delay in infection by 2 to 3 days. The current results support previous findings indicating involveme...
Journal of nematology, 2015
Sting nematode (Belonolaimus longicaudatus) is an economically important ectoparasitic nematode t... more Sting nematode (Belonolaimus longicaudatus) is an economically important ectoparasitic nematode that is highly pathogenic on a wide range of agricultural crops in sandy soils of the southeastern United States. Although this species is commonly found in Florida in hardwood forests and as a soilborne pathogen on turfgrasses and numerous agronomic and horticultural crops, it has not been reported infecting peanut. In the summers of 2012 and 2013, sting nematode was found infecting three different peanut cultivars being grown on two separate peanut farms in Levy County, FL. The damage consisted of large irregular patches of stunted, chlorotic plants at both farms. The root systems were severely abbreviated and there were numerous punctate-like isolated lesions observed on pegs and pods of infected plants. Sting nematodes were extracted from soil collected around the roots of diseased peanut over the course of the peanut season at both farm sites. Peanut yield from one of these nematode-...
Plant Disease, 2012
In March 2010, citrus black spot symptoms were observed on sweet orange trees in a grove near Imm... more In March 2010, citrus black spot symptoms were observed on sweet orange trees in a grove near Immokalee, FL. Symptoms observed on fruit included hard spot, cracked spot, and early virulent spot. Hard spot lesions were up to 5 mm, depressed with a chocolate margin and a necrotic, tan center, often with black pycnidia (140 to 200 μm) present. Cracked spot lesions were large (15 mm), dark brown, with diffuse margins and raised cracks. In some cases, hard spots formed in the center of lesions. Early virulent spot lesions were small (up to 7 mm long), bright red, irregular, indented, and often with many pycnidia. In addition, small (2 to 3 mm), elliptical, reddish brown leaf lesions with depressed tan centers were observed on some trees with symptomatic fruit. Chlorotic halos appeared as they aged. Most leaves had single lesions, occasionally up to four per leaf. Tissue pieces from hard spots and early virulent spots were placed aseptically on potato dextrose agar (PDA), oatmeal agar, or...
Experimental Parasitology, 1984
Caenorhabditis elegans and Panagrellus redivivus: Enzyme-mediated modification of chemotaxis. Exp... more Caenorhabditis elegans and Panagrellus redivivus: Enzyme-mediated modification of chemotaxis. Experimental Parasitology 58, 270-277. Treatment with mannosidase or sialidase completely inhibited chemotactic responses of Caenorhabditis elegans wild type, C. elegans mutants CB1377 (daf-6)X and CB1379 (the-3)I, and Panagrellus redivivus to a source of attractants. Trypsin (EC3.4.21.4) caused a partial reduction in the level of chemoresponse. Normal chemotaxis was renewed within 20 hr following exposure to the enzymes. Other enzymes tested had no effect. Experimental and supporting evidence is presented that behavioral modification resulted from functional impairments to receptors located within chemosensory SenSik3.
Experimental Parasitology, 1985
Caenorhabditis elegans: Lectin-mediated modification of chemotaxis. Experimental Parasitology 59,... more Caenorhabditis elegans: Lectin-mediated modification of chemotaxis. Experimental Parasitology 59, 90-97. Binding of the lectins concanavalin A (Con A) and limulin to Caenorhabditis e/egans wild type resulted in consistent, reproducible, partial inhibiton of chemoattraction to sterile filtrates of Escherichia coli. Normal chemotaxis resumed within 8 hr following treatment with these lectins. Competitive displacement of Con A or limulin by flooding with the specific sugars resulted in rapid resumption of normal chemotactic behavior. The experimental protocol for Con A applied to three age groups (newly hatched larvae, young adults, and old adults) showed the same response for all groups tested. Two mutant C. elegans with morphological defects in the cephalic chemosensilla showed the same inhibition of chemotactic response after exposure to Con A, and rapidly resumed normal behavior after competitive displacement of the lectin. Limulin and Con A did not affect nematode growth, development, or longevity, demonstrating that the observed results were not attributable to toxic effects. These results and other experimental evidence support the premise that behavioral modification was caused by functional impairments caused by Con A and limulin to chemoreceptors located on sensory dendrites of the cephalic sensilla.
Plant Disease, 2016
Bacterial spot of tomato, a major problem in many tomato production areas, is caused by Xanthomon... more Bacterial spot of tomato, a major problem in many tomato production areas, is caused by Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri. In order to detect and identify the bacterial spot pathogens, we evaluated a region of hrpB operon as a source for primers and probes for real-time polymerase chain reaction (PCR). A 420-bp fragment of the hrpB7 gene was amplified by PCR from 75 strains representing the four species. The PCR products were sequenced and phylogenetic analysis revealed that hrpB7 is highly conserved within each species, with a single-nucleotide polymorphism (SNP) among the X. vesicatoria strains. X. euvesicatoria and X. perforans varied by two SNP. Four probes and two primer sets were designed to target the four bacterial spot pathogens based on their hrpB7 gene sequences. In order to simultaneously detect the four bacterial spot pathogens, the four probes and two primer sets were optimized for a multiplex real-time TaqMan PCR assay. The optim...
Journal of nematology, 1987
Significant control of tomato root knot was achieved by applications of the lectins Concanavalin ... more Significant control of tomato root knot was achieved by applications of the lectins Concanavalin A (Con A) and Limax flavus agglutinin in greenhouse, growth chamber, and microplot trials. Four consecutive weekly applications at lower concentrations of Con A yielded better control than single applications at a higher total concentration. The present state of knowledge on binding of Con A to soil nematodes and the in vitro effect of this lectin in chemotactic behavior are discussed. The mode of action of Con A on root-knot control is unknown.
World Academy of Science, Engineering and Technology, International Journal of Biotechnology and Bioengineering, 2016
The accidental importation of plant pathogens in or on the bodies of parasitoids im- ported as na... more The accidental importation of plant pathogens in or on the bodies of parasitoids im- ported as natural enemies has been raised as a potential risk of classical biological control projects involving insects that serve as vectors of plant diseases. During quarantine evaluation of two parasi- toids, Tamarixia radiata Waterston (Hymenoptera: Eulophidae) and Diaphorencyrtus aligarhensis (Shafee, Alam and Agarwal) (Hymenoptera: Encyrtidae), imported for classical biological control of Asian citrus psylla Diaphorina citri (Kuwayama) in Florida, we were asked to determine that these parasitoids were free of the causal agent of Asian greening disease, the bacterium Liberobacter asiaticum (L.) Jack. Preliminary tests using allele-specific polymerase chain reaction (Standard PCR) suggested the assays were prone to false negatives. Another PCR protocol, Long PCR, previously was shown to be more reliable than Standard PCR when screening insects for another bacterium (Wolbachia) (Jeyaprakash and ...
Insect Molecular Biology, 2000
Bacteria belonging to the genus Wolbachia are associated with a variety of reproductive anomalies... more Bacteria belonging to the genus Wolbachia are associated with a variety of reproductive anomalies in arthropods. Allele-specific polymerase chain reaction (= Standard PCR) routinely has been used to amplify Wolbachia DNA from arthropods. While testing the two-spotted spider mite Tetranychus urticae and other arthropods known to be infected with Wolbachia , Standard PCR frequently produced false negatives, perhaps because the DNA from the arthropod host interfered with amplification by Taq DNA polymerase. Long PCR, which uses two enzymes (Taq and Pwo), consistently amplified Wolbachia DNA and a sensitivity analysis indicated that Long PCR was approximately six orders of magnitude more sensitive than Standard PCR in amplifying plasmid DNA spiked into insect genomic DNA. A survey indicated that 76% of sixty-two arthropod species and two subspecies in thirteen orders tested positive for the Wolbachia wsp sequence by Long PCR, which is considerably higher than the rate of 16.9% obtained previously for the ftsZ sequence using Standard PCR (Werren, J.H., Windsor, D. and Gao, L. (1995a) Proc R Soc Lond B 262: 197-204). A subsample of Long PCR products from fourteen arthropod species and two subspecies were sequenced, both directly and after cloning. Two A-and eleven B-Wolbachia strains were detected and their wsp sequences displayed a maximum of 23.7% sequence divergence at this locus. Two new groups (named Fus and Ten) were identified in addition to nineteen reported earlier (
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Papers by Ayyamperumal Jeyaprakash