James D. Willett

Determination of chromium in orchard leaves by reversed-phase high-performance liquid chromatography

Abstract Chromium, as chromium acetylacetonate, was determined in nitric acid digested samples of NBS Standard Reference Material 1571, Orchard Leaf by reversed-phase high-performance liquid chromatography on μBondapak C18 using 36% acetonitrile in water. The determined value was 2.4 ± 0.1 ppm. The limits of detection for this method are 1 ng on-column injection. By standard microchemical enrichment techniques parts-per-billion analyses can be achieved.

Cyclic nucleotide exudation by nematodes and the effects on nematode growth, development and longevity

The levels of the cyclic nucleotides, cAMP and cGMP, in the medium of aging mass cultures of Panagrellus redivivus were determined, respectively, by a protein binding assay and a radio-immunoassay. The amount of cGMP increased as the mass cultures aged while the amount of cAMP remained stable. Since premature death and an inhibition of development have been observed in aging mass cultures, investigators have speculated that a build-up of excretory products in the medium might be toxic to the nematodes and cause abnormal development.To examine this possibility, small cultures containing fixed numbers of the nematode Caenorhabditis elegans were exposed to levels of cGMP analagous to the levels found in aging mass cultures of P. redivivus. Significant increases in growth and longevity occurred with no effect on fecundity, timing or the duration of the reproductive period. It appears then that cGMP is not responsible for the toxic effects observed in mass culture and, in fact, cGMP apparently enhances nematode longevity at concentrations which do not alter normal development.

Age-synchronous culture of Caenorhabditis elegans: technique and applications

The inclusion of mobility to an age synchrony method and the development of an inexpensive filter device resulted in a natural model aging system without resorting to invasive chemical techniques. Large or small cohorts of nematodes with less than 1% offspring contamination are possible. The filter/mobility method is compared to other methods using the same strain and culture temperature. The applicability of the method is shown with a variety of parameters, and a previously reported parameter of aging in nematodes, i.e., specific gravity, is shown not to be an aging parameter of Caenorhabditis elegans.

Applications of Cold Temperature Stress to Age Fractionate Caenorhabditis elegans: A Simple Inexpensive Technique

The nematode Caenorhabditis elegans’s (CE) successful use in studies of aging is well documented. Cold temperature stress of mixed populations of CE provides a rapid inexpensive means of obtaining three life stage–specific cohorts. Cohorts are obtained in quantities that allow acquisition of replicate metabolite profiles of changes associated with development, aging, and senescence. The fractionation technique is effective with monoxenic and axenic CE cultures. Cohort Y contains 100% young worms, and Cohort A contains 75% adult worms. Cohort M, prereproductive and reproductive, contains some A and Y due to continuous egg laying and hatch. Principal component analysis of normalized data from metabolite profiles obtained using high-performance liquid chromatography electrochemical analysis clearly separates Cohort Y from Cohort A and monoxenic from axenic cultured worms. Access to replicate quantities of age-defined worms will aid studies of alterations in homeostatic controls associated with aging and senescence.

Using Caenorhabditis elegans as a Tool for Identifying Environmental Lead Contamination: A new endpoint for relating exposures to lead risk

Nematodes have been used as test organisms for many new endpoints in toxicity. Much of this has been reported in texts and in the Wormbook, published by the C.elegans research community. Key factors in measuring toxicity are the amount of toxic material absorbed and its bioavailability. This study demonstrates that there are markers for toxicity that respond to both toxicity and the bioavailability, thus providing data points to accurately express the real environmental threat. Alterations in key metabolites of the tryptophan pathway were observed in studies of C. elegans exposed to soluble and insoluble lead. The changes observed correlate to the metals bioavailability. Of note was the increase in anthranilic acid (AA) production with increasing exposure to bioavailable lead. This was the only metabolite of tryptophan that showed any increase in concentration. Nematodes exposed to other metals of environmental significance including cadmium, tin and arsenic at concentration levels found in contaminated ...

A Method for Age Synchrony of Panagrellus Redivivus in Xenic Culture

A method for synchronizing yeast fed populations of female Panagrellus redivivus has been developed. Synchronous cultures are begun with 1 or 2 day old larvae and resynchronized at 7 days of age and every 3 days thereafter. Synchrony is obtained by separating parents from progeny, and females from males, on sucrose gradients. Using this method synchrony has been maintained from the peak of reproduction to the median life span of individuals in selected populations.

Quantitative Determination of Several Metallic Elements in Whole Cysts of Heterodera Schachtii By Neutron Activation Analysis

Field collected cysts of Heterodera schachtii were analyzed for a variety of metals by neutron activation analysis. Significant differences are observed in the levels of zinc and vanadium found in cysts collected from fallow soil in the spring as compared with cysts collected immediately after harvest in the fall.

Genomics, proteomics: what’s next?

The Genome: DNA, the genomic material of all life’s forms, is the archival information of life, the blue print for the architecture and the engines of the cell. The Proteome: Proteins, the gene products defined within the cell’s blueprint, are the cell’s architecture and engines. The Metabolome: Small, usually monomeric, molecular metabolites of the cell that comprise the fundamental materials for macromolecular assemblage, energy exchange and signal transduction. Within this set of molecules reside the system controls of the cell and the foundations of cellular homeostasis; ‘The cell’s Software.’

Anti-aging dilemma: to restore the hardware or to reinstall the software?

Sinceitsearlydays,thevalueofdecipheringthehumanDNAhasbeenseenprimarilyinextractingthe set of messages that run the cells that constitute the body. In common understanding, thesemessages are encoded in DNA and transcribed as cell-specific sets of RNAs, some of which aretranslatedtoproteins,thenmodifiedwithvariouspost-translationaladd-onsmadeofsugars,lipidsand other moieties. This complex chain of events is further complicated by multi-layered possi-bilities for the modifications allowed at every step–epigenetics for DNA, editing for RNAs andtherecentlydiscoveredphenomenonofnon-templatepolypeptideextensionallowedbyribosomes(Shen et al., 2015). It seems that when looked at as a whole, the DNA, and all the messages associ-ated with DNA, do not look like a blueprint, or even a clear set of instructions, but rather a messydraft or a stack of notes that are scribbled all over and full of ambiguities.However, let us hack through the majority of the “omics” and look upon the set of smallmolecules known as metabolites, and the budding discipline of Metabolomics that researches thetrueunderpinningsoftheabundantlycomplexmechanicsofthelivingcell.Itisworthwhiletonotethat,toasomewhatdefineddegree,thecellwilltoleratethelossofageneorchangesinthelevelsofRNAs or even the most important of proteins, while even slight deregulation of the levels of someof the smallest metabolites leads to immediate and catastrophic consequences. The potassium ionandATPmaybeusedastheprimaryexamplesofsmallestmoleculescapableofelicitingasystemicresponse.Accordingtoourcalculation,amere0.5%increaseinthetotalcontentofpotassiumchlo-ride, one of the most common electrolytes in the human body, leads to immediate cardiac arrest.TheconsequencesofthedepletionofATPmaymanifestasavarietyofailments,withtheirdurationinversely proportional to the severity of the defect. Aging, in particular, is associated with a declinein the efficiency of oxidative phosphorylation and an increase in the risk of resulting pathologies.Of course, there are other small molecules, possibly not as well-known as ATP, but still indispens-able and irreplaceable. In particular, the metabolites derived from the amino acid tryptophan havethe capacity for similar dramatic alteration of system-wide function. Most pertinent to the topicof this discussion, the changes in metabolic profiles are considered as drivers for the pathogene-sis of age-associated disorders, including Alzheimer’s disease (Tacutu et al., 2010; Demetrius andDriver, 2013; Jia et al., 2014; Obre and Rossignol, 2015). It also is of note that metabolites are notasabundantascommonlystudiedspeciesofproteinsandRNAs.Hence,theworldofmetabolitesisimmensely easier to comprehend than the overly complicated world of other famous “omics.” Thelatter point is extremely important, as it provides a possibility for the use of a powerful reduction-ist approach without falling into ill-fitting or over-fitting of the underlying model, a well-knownperpetual source of entrapment.Letuscomparetheliving(andaging)cell,withitsendless“omics”-scalelayersofinterconnectedcomponents, to modern computers. Computer hardware is a collection of interconnected physicaldevices used in or with your machine. One of these parts may wear itself out and die; however,

Isolation and identification of lanosterol as a normal constituent of the lipids of the free living nematode Panagrellus redivivus.

1. 1. The lipids of the free-living nematode Panagrellus redivivus were examined for C30 triterpenes. 2. 2. The common sterol precursor lanosterol was identified as a constituent of the lipids of Panagrellus redivivus.