Bert M. Zuckerman

The aging process of the nematode Caenorhabditis elegans in bacterial and axenic culture

Abstract While much is known of the morphological and some physiological changes which occur during the aging of Caenorhabditis elegans, little attempt has been made to measure the changes in behaviour. Wild type C. elegans (var. Bristol) were cultured axenically, individually observed each day for 15 minutes and their behavioural actions recorded on a multi-channel event recorder or on a video tape recorder of a closed circuit TV- Particular attention was paid to the rate of backwardly directed somatic waves, pharyngeal bulb pulsations, the interval between defecations and oviposition. C. elegans lived significantly longer in axenic culture than in bacteria. A gradual linear decline occurred in the rate of backward waves between maturation (day 4) and death (day 20) for those worms in axenic culture. In striking contrast, the mean maximum rate of pharyngeal bulb pulsations maintained a plateau from day 4 to 18, while the mean interval between defecations doubled from 60 sec (days 4 to 8) to 120 sec (days...

A strain of Bacillus thuringiensis for the control of plant-parasitic nematodes.

An isolate of Bacillus thuringiensis, designated CR‐371, was evaluated for efficacy in controlling plant‐parasitic nematodes. This isolate was first shown to be nematicidal to Caenorhabditis elegans in an in vitro laboratory assay. Treatment resulted in a significant reduction in galls due to root‐knot nematode on tomato in a greenhouse trial. In two field trials in Puerto Rico, CR‐371‐treated tomatoes and pepper had significantly fewer root galls due to Meloidogyne incognita than untreated controls, and populations of Rotylenchulus reniformis were smaller. In one experiment, CR‐371 treatment was associated with significant increases in pepper yields, while in the second trial small yield increases of pepper and tomato occurred. In a greenhouse trial, incorporation of CR‐371 into a methyl cellulose seed coat gave similar control of root‐knot nematode on tomato as compared to CR‐371 applied as a drench. CR‐371‐treated strawberry plants also had smaller populations of Pratylenchus penetrans in roots in a gr...

The distribution and persistence of diazinon applied to plant and soil and its influence on rhizosphere and soil microflora

Summary1. Evidence was obtained of the rapid translocation of radioactive Diazion through bean plants and its emergence in bean root exudates maintained under sterile conditions.2. The presence of bean rhizosphere microflora did not appear to be a factor in the metabolism of Diazinon by the bean plant.3. Diazinon applied at the rate of 3 lbs per acre to soil under non-sterile conditions persisted for as long as 180 days after application. No Diazinon was detectable after 10 weeks in soil receiving 0.3 lbs per acre.4. Diazinon or its degradation products exerted a selective effect common to both soil and rhizosphere microflora which expressed itself in the selective enrichment of a cocoidal rod. Numbers of fungi seemed unaffected by the presence of Diazinon. After 180 days a large number of the genus Streptomyces appeared as a seeming climax population.5. The predominant microbial isolate utilized Diazinon as a sulfur, phosphorus, carbon and nitrogen source in that order of preference. The biodegradability of Diazinon was conditioned by its solubilization in a suitable carrier, and by the presence of an additional carbon source.

Caenorhabditis briggsae and C. elegans: partial characterization of cuticle surface carbohydrates.

Abstract The presence of galactose, glucose, mannose, and N-acetylglucosamine on the exposed surface of the nematodes Caenorhabditis briggsae and C. elegans was indicated by specific binding of three iodinated plant lectins. Proteolysis experiments suggested the absence of digestible glycoproteins on the exposed surfaces of the two nematode species. High resolution micrographs of cuticle surface preparations labeled with cationized ferritin indicated that the negative charge-bearing molecules are more densely packed on the nematode surface than on animal plasma membranes.

Aging in Caenorhabditis briggsae.

Caenorhabditis briggsae was used as a model to study aging of a metazoan under gnotobiotic conditions. At higher temperatures nematodes were shorter-lived and had a shorter generation time. Nematodes moved more slowly as they aged. Physiologic aging was marked by a decreased ability to withstand osmotic stress, a possible increase in the bodys internal solute concentration, and increased sensitivity to formaldehyde. These results suggest that the ability to osmoregulate and the permeability of the body wall are altered during senescence. The interchordal hypodermis, as well as the chordal hypodermis, contained fairly abundant structures having biosynthetic activity. During aging mitochondria of the hypodermis degenerated, some areas of the thin hypodermal band thickened and lysosome-like bodies formed in the interchordal hypodermis. Changes in osmoregulatory and excretory mechanisms are probably associated with deterioration of the hypodermis organelles.

Effects of vitamin E on the nematode Caenorhabditis elegans

Vitamin E at 200 μg/ml significantly extended the mean lifespan and extended maximum lifespan of the nematode Caenorhabditis elegans when supplied early in the prereproductive stage. At this concentration, vitamin E increased growth, but did not affect fecundity or the length of the reproductive period. The vitamin E effect was not passed from the parents to the progeny. Evaluations of the effects of vitamin E on lipofuscin accumulation were inconclusive. The results are compared to previous studies on C. briggsae and Turbatrix aceti.

Caenorhabditis briggsae: aging and the structural turnover of the outer cuticle surface and the intestine.

Abstract The exposed surface of Caenorhabditis briggsae was examined for the presence of neuraminic acid, hyaluronic acid, and glucuronic acid. None of these molecules was detected. In young nematodes the presence of a surface coat was demonstrated. This surface coat appeared to shrink with age. Ruthenium red staining suggested the presence of acid mucopoly-saccharides on the outer surface. Feeding the nematodes on cationized ferritin enabled visualization of a matrix surrounding the intestinal brush border. Experiments with an inhibitor of acid mucopolysaccharide synthesis suggested that there is no turnover of acid mucopolysaccharides after the final molt of C. briggsae .

A novel Streptomyces species for controlling plant-parasitic nematodes

A novel species ofSteptromyces isolated from nematode suppressive soils in Costa Rica was evaluated for efficacy in controlling plant-parasitic nematodes. This isolate, designated CR-43, was shown to inhibit reproduction ofCaenorhabditis elegans in a laboratory assay. Greenhouse trials utilizing three different methods of treatment with CR-43 gave significant reductions of tomato root galling due toMeloidogyne incognita. In a field experiment in Puerto Rico, in soil naturally infested withM. incognita, CR-43-treated pepper showed significant reductions in root galling and significant increases in yield as compared to untreated controls. In a second experiment in Puerto Rico, a significant reduction in tomato root galling and a slight reduction in root galling on pepper occurred. In this trial, yields on both tomato and pepper were higher in CR-43 treatments, but these differences were not statistically significant. In both experiments populations ofRotylenchulus reniformis were reduced by CR-43 treatment. In a field trial on strawberry in Massachusetts, CR-43-treated plants had lower numbers ofPratylenchus penetrons within roots and showed a significant decrease in black root rot disease. Studies on sterile filtrates from CR-43 cultures indicated that a major determinant of CR-43 antinematodal activity was mostly thermostable macromolecules of molecular weight higher than 6000. Culture filtrates of CR-43 exhibited antifungal activity in vitro.

Caenorhabditis elegans: lectin-mediated modification of chemotaxis.

Binding of the lectins concanavalin A (Con A) and limulin to Caenorhabditis elegans wild type resulted in consistent, reproducible, partial inhibition 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.

Caenorhabditis elegans and Panagrellus redivivus: Enzyme-mediated modification of chemotaxis

Treatment with mannosidase or sialidase completely inhibited chemotactic responses of Caenorhabditis elegans wild type, C. elegans mutants CB1377 (daf-6)X and CB1379 (che-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 sensilla.