Molecular modeling of hapten structure and relevance to broad specificity immunoassay of sulfonamide antibiotics.

Molecular modeling of hapten structure was used to predict and influence, through appropriate synthetic work, the outcome of an immunization program. Examination of the structures of sulfonamide antibiotics led to the development of a hypothesis and the consequent synthesis of a sulfacetamide-protein immunogen aimed at the generation of broad specificity anti-sulfonamide antibodies. The antisera generated, alongside anti-sulfachlorpyradizine antisera generated at the same time, were characterized for cross-reactions against a range of sulfonamide drugs, and were found to exhibit good but not the desired broad specificity. Discussion is presented as to the reasons for the failure of the hypothesis. Further hypotheses are developed and speculation is made as to the future of molecular modeling in immunochemical research.     

X-linkage of a vitellogenin gene in Locusta migratoria

Hybridization of a cloned DNA probe to blots of restriction digests of Locusta migratoria genomic DNA showed that a vitellogenin gene is present at one copy per haploid genome in females, and at only one-half that number in males. The genomic region encompassing the 3′-coding end of the gene is polymorphic, as revealed by blots of DNA from individual locusts. DNA from some female locusts yielded two variants in this region, whereas a series of male locusts showed one variant or the other, but never both. The results demonstrate that the vitellogenin gene, which is normally expressed only in females, is X-linked in L. migratoria.     

Absence of 6-Hydroxydopamine in the Rat Brain After Treatment with Stimulants and Other Dopaminergic Agents: A Mass Fragmentographic Study

Abstract: Formation of 6-hydroxydopamine (6-OHDA) from dopamine has been hypothesized to mediate neuro-degeneration induced by some psychostimulants. Although the emergence of a 6-OHDA-like substance was reported in the striatum of methamphetamine-treated rats, this substance has not been identified by a direct approach. We used mass fragmentography to search for 6-OHDA in the rat frontal cortex and striatum after the administration of a number of drugs including 3,4-dihy-droxyphenyl-L-alanine, methamphetamine, amphetamine, and cocaine, all of which increase synaptic dopamine. No 6-OHDA was detected after the acute systemic administration of these agents. Intraventricular administration of 6-OHDA (10 μg/rat.) produced measurable concentrations of 6-OHDA that were higher in the striatum than in the frontal cortex. Intraventricular administration of 2,4,5-trihydroxy-phenyl-D,L-alanine (6-OHDOPA; 10 μg/rat) produced similar concentrations of 6-OHDA in both regions. Pargyline, but not carbidopa (α-methyldopahydrazine), enhanced the effect of intraperitoneal 6-OHDOPA administration (80 mg/kg). We conclude that (1) 6-OHDOPA can cross the blood-brain barrier and is converted to 6-OHDA in the brain, (2) 6-OHDA is a substrate for monoamine oxidase(s) and therefore a search for its purported deaminated metabolite is warranted, and (3) acute treatment with the above stimulants either does not lead to the formation of 6-OHDA or produces concentrations below the detection limit of the assay (<34 pg/mg of protein).     

Life histories and production of three Rocky Mountain aquatic insects along an elevation-driven temperature gradient

Hydrobiologia - Although temperature is known to influence individual traits such as growth, body size, and fecundity, few studies have examined how these relationships influence population-level...