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Y Spiegel

Publications and source records attributed to Y Spiegel.

12 recordsLinked to original sources
PubMed2002

Characterization of Meloidogyne javanica surface coat with antibodies and their effect on nematode behaviour.

The surface coat of the 2nd-stage juveniles (J2) of plant-parasitic nematodes is considered to be involved in interactions with microorganisms in the soil and rhizosphere, as well as with the host plant. Characterization of surface antigens might be important in the development of new nematode control strategies. In this study, polyclonal and monoclonal antibodies raised against Meloidogyne javanica, M. incognita and other plant-parasitic nematodes were tested for their binding to the surface coat and secreted-excreted products of M. javanica. Some of the monoclonal and polyclonal antibodies raised against M. incognita showed cross-reactivity with the surface coat of M. javanica. Western blot analysis of M. javanica surface coat extracts revealed labelling of several polypeptides with a 48 kDa main band for the polyclonal antibody IACR-PC Mi 373, and a 55 kDa main band for PC Mj E2. Further characterization of the antigens recognized by the polyclonal antibody PC Mj E2, in planta, showed that they were present in the parasitic stages J2 and J3 and that the surface coat was shed during root penetration. The hypodermis of the infective juveniles was labelled by PC Mj E2 and the monoclonal antibody IACR-Misec 3F.4, suggesting that these surface antigens are produced in the hypodermis. Nematode behaviour was affected by all the antibodies that bound to the surface coat of the pre-parasitic J2, and we demonstrated that the movement pattern of the M. javanica J2 was affected by these antibodies. Continuous binding of the antibodies to the M. javanica surface inhibited the infection of Arabidopsis thaliana roots on agar plates.

Animals↗
PubMed2001

Isolation of a novel collagen gene (Mj-col-5) in Meloidogyne javanica and analysis of its expression pattern.

Mj-col-5, isolated from the plant parasitic nematode Meloidogyne javanica, has a longer carboxy-terminus than other members of the Caenorhabditis elegans COL-6 subfamily of cuticle collagen, including an extra tyrosine residue, and may form altered nonreducible cross-linkages. By semiquantitative determination at different life stages, Mj-col-5 transcript was shown to be more abundant in eggs than in juveniles/young females and adult females. To characterize further this gene's contribution to the changing cuticle of the nematode, we expressed a fusion protein containing a nonconserved 58-amino-acid sequence from the putative Mj-col-5 gene product and raised rabbit antiserum against the fusion protein. The antiserum detected a strongly reacting band (36 kDa, designated MJE36) on western blots of M. javanica eggs extracted with beta-mercaptoethanol. MJE36 was sensitive to collagenase and was not detected on western blots of extracts from M. javanica second-stage juveniles or adult females. A band of the same molecular size was detected in Meloidogyne incognita egg extracts but not in those of Heterodera avenae. Immunoblot indicated that MJE36 is not present in egg shells of M. javanica.

Amino Acid Sequence↗
PubMed1997

The first isolated collagen gene of the root-knot nematode Meloidogyne javanica is developmentally regulated.

The nematode's surface comprises a multilayered cuticle, which consists mainly of collagen proteins. We identified, cloned and characterized the first cuticular collagen gene, Mjcol-3, of the plant-parasitic nematode Meloidogyne javanica. The gene putatively encodes a 32.4-kDa collagen protein, including a propeptide which possesses a subtilisin-like protease-cleavage site. Six introns were identified in the gene sequence, with three slightly different acceptor-splicing sites. The basic structure of the predicted MJCOL-3 protein sequence is highly similar to that of the Caenorhabditis elegans DPY-7, with 65.9% identity between the two amino acid sequences. Relative to DPY-7, the putative MJCOL-3 protein has a shorter carboxy-terminus. This non-conserved feature may indicate different contributions of DPY-7 and MJCOL-3 collagens to the structure of the cuticle. Mjcol-3 is developmentally regulated: transcripts were found mainly in preparasitic developing eggs, less in parasitic third- and fourth-stage juveniles and young females shortly after the fourth molt, and much less in females before egg-laying.

Amino Acid Sequence↗
PubMed1997

Meloidogyne javanica surface proteins: characterization and lability.

Characterization of surface coat (SC) proteins including carbohydrate-binding proteins and glycoproteins of the plant-parasitic nematode Meloidogyne javanica 2nd-stage juvenile (J2) is reported. Extraction of surface proteins with sodium dodecyl sulfate (SDS) and separation by denaturing polyacrylamide gel electrophoresis (SDS-PAGE) results with bands at 6, 9, 14, 22, 26, 31, 46, 49, 58, 66, 80, 205 and 250 kDa. On Western blots, the neoglycoprotein, fucosylated-, mannosylated- and glucosylated-bovine serum albumin, reacted with the 14, 22, 26, 58 and 66 kDa bands. The lectins, Concanavalin A and wheat-germ agglutinin (WGA) labelled surface protein bands of 6, 9, 14, 31, 58 and 66 kDa; WGA also labelled the 22 and 26 kDA bands. Biotin reagents were used to specifically trace surface proteins on live J2. SDS-PAGE of biotinylated J2 extracts revealed only 2 specific biotin-protein bands at 46 and 49 kDa. The labile and transitory nature of Meloidogyne javanica SC was demonstrated by the dynamics of human red blood cells (HRBC) adherence to J2 of different ages. HRBC adherence was also used to demonstrate the SC recovery of detergent-treated J2, which was further exhibited in the SDS-PAGE profiles.

Animals↗
PubMed1997

An immunoreactive protein to wheat-germ agglutinin antibody is induced in oat roots following invasion of the cereal cyst nematode Heterodera avenae, and by jasmonate.

A protein that cross-reacts to a wheat-germ agglutinin antibody was induced in oat roots following the invasion of second-stage juveniles (J2) of the cereal cyst nematode Heterodera avenae. This protein, designated ASP45, was acid soluble, and its molecular mass was about 45 kDa on a sodium dodecyl sulfate-polyacrylamide gel. ASP45 was induced in both compatible and incompatible interactions between the nematode and the plant, and also in roots by exposure to jasmonic acid (JA) or methyl jasmonate. However, ASP45 was not induced by elicitors of pathogenesis-related proteins, abscisic acid, or wounding. Lipoxygenase activity, which is involved in JA synthesis, was higher in nematode-infected and JA-treated roots than in their noninfected, untreated counterparts. Inhibition of lipoxygenase activity in roots abolished ASP45 induction in the nematode-infected roots. Amino acid sequences similar to that of ASP45 were found in chitinases of poplar tree and Arabidopsis, even though ASP45 showed no chitinase activity. Although the biological role of ASP45 in infected roots is not clear, JA is suggested to be involved in signal transduction after pathogen invasion of the plant.

Acetates↗
PubMed1995

Carbohydrate-recognition domains on the surface of phytophagous nematodes.

Human red blood cells (HRBC) adhered to preparasitic second-stage juveniles (J2) of Heterodera avenae, Heterodera schachtii, Meloidogyne javanica, Pratylenchus mediterraneus, Rotylenchulus reniformis, and Tylenchulus semipenetrans over the entire nematode body. Binding was conspicuously confined to the head and tail of Longidorus cohni, Xiphinema brevicolle, and Xiphinema index. Binding was Ca2+ and Mg2+ dependent. In contrast, HRBC did not adhere to Anguina tritici, Aphelenchoides subtenius, Ditylenchus dipsaci, M. javanica females, and Panagrellus redivivus, even in the presence of these cations. Incubation of M. javanica J2 with fucose, glucose, N-acetylglucosamine, mannose, or trypsin decreased the intensity of subsequent HRBC binding, while galactose and N-acetylgalactosamine increased binding intensity. HRBC binding was diminished when nematodes were pretreated with trypsin and eliminated when pretreatments with detergents removed the surface coat. HRBC adhered to nylon fibers coated with surface coat extracted from M. javanica J2; binding was Ca2+ and Mg2+ dependent and diminished when the nylon fibers were coated with bovine serum albumin or preincubated with fucose and mannose. These results demonstrate that HRBC adhesion involves carbohydrate moieties of HRBC and corresponding carbohydrate-recognition domains (CRD) distributed in the nematode surface coat. To our knowledge this is the first report of a surface CRD in the phylum Nematoda.

Animals↗
PubMed1993

Rawlsian optimal population size.

"In this paper, I examine the implications of the Rawlsian maximin criterion for optimal population size and intergenerational allocation of resource when fertility is endogenous. I show that whenever children are better-off than their parents in laissez-faire, then the size of the population and parental bequests are also optimal according to the Rawlsian criterion....I then show that by using proper price-based corrective policies, society can achieve a Rawlsian optimal allocation."

Demography↗
PubMed1993

Telluria mixta (Pseudomonas mixta Bowman, Sly, and Hayward 1988) gen. nov., comb. nov., and Telluria chitinolytica sp. nov., soil-dwelling organisms which actively degrade polysaccharides.

Pseudomonas mixta (type strain, ACM 1762 [= ATCC 49108], an actively dextranolytic species that possesses both lateral and polar flagella, was compared with the strictly aerobic, rod-shaped, chitinolytic bacterium "Pseudomonas chitinolytica" ACM 3522T (= CNCM I-804) (T = type strain), which has a similar flagellation pattern, by performing phenotypic characterization and DNA-DNA hybridization studies and by analyzing DNA base compositions and 16S rRNA sequences. Our results indicated that "P. chitinolytica" ACM 3522T was phenotypically and genotypically distinct from P. mixta and other phenotypically analogous Pseudomonas spp., Xanthomonas maltophilia, and other aerobic chitin degraders. The 16S rRNA sequences of strains ACM 1762T and ACM 3522T were found to be very similar (97%) to each other and indicated that these organisms are proteobacteria that belong to the beta subclass. The strains were deeply branched in the beta subclass and were distinct from other pseudomonads, including Pseudomonas cepacia, and from Comamonas testosteroni. On the basis of phenotypic, genotypic, and phylogenetic evidence, it is proposed that P. mixta and "P. chitinolytica" ACM 3522T represent two distinct species in a new genus called Telluria. Thus, the genus Telluria gen. nov. contains Telluria mixta comb. nov. and Telluria chitinolytica sp. nov., which are strictly aerobic, rod-shaped, soil-dwelling bacteria that are active polysaccharide degraders.

Base Composition↗
PubMed1978

Crisis intervention with families of servicemen missing in action.

This study investigated reactions and processes in a crisis situation as well as experiences of those who engaged in crisis intervention activities. Thirty-two volunteers, who worked with 55 families of servicemen missing in action during the October 1973 Mideast war, described the families' reactions to the given situation as well as their own involvement. Reactions to crisis and expectations from the volunteers are described and discussed. Special scrutiny was directed at the volunteering phenomenon, and at the volunteers' motivations, needs, reactions, and conflicts.

Adaptation, Psychological↗