The ecology and evolution of host-plant resistance to insects.

Genetic techniques have yielded new insights into plant-herbivore coevolution. Quantitative genetic tests of herbivory theory reveal that in some cases insect herbivores impose selection on resistance traits. Also, some resistance traits are costly while others appear not to be, and genetic models can explain these results.

Unexpected loss of genomic DNA from agarose gel plugs.

Intact chromosomal DNAs are routinely prepared by embedding cells in agarose plugs before lysis. The large sizes of the genomic DNAs cause their retention while other macromolecules diffuse into and out of the gel matrix during lysis, washing and restriction cleavage incubations. However, in an analysis of agarose-embedded chromosomal DNAs cleaved with restriction enzymes, fragments larger than 30 kilobases were found to have eluted from the gel plugs.

How to keep your best people for the '90s.

Getting good people to join us merely sets the stage for achievement. the real payoff depends on how we deal with them and how long they stay. From the CEO's perspective, the most important requirements for the '90s are: Know what you mean by performance in all jobs, in all functions, and at all levels.

Primary and secondary structural analyses of glutathione S-transferase pi from human placenta.

The primary structure of glutathione S-transferase (GST) pi from a single human placenta was determined. The structure was established by chemical characterization of tryptic and cyanogen bromide peptides as well as automated sequence analysis of the intact enzyme. The structural analysis indicated that the protein is comprised of 209 amino acid residues and gave no evidence of post-translational modifications.

Effects of genetic and environmental variation on resistance of willow to sawflies.

An experiment was performed to test the effects of clone genotype, spatial variation (sites), temporal variation (years), and their interaction on the densities of four sawfly species that form galls on willow. Clone genotype had a significant effect on the densities of three species over both levels of spatial and temporal variation. Genotype was not important at one site, but was significant for 3 species at another site.

Localization of an encephalitogenic epitope for the SJL mouse in the N-terminal region of myelin basic protein.

T cells from SJL mice reactive with myelin basic protein peptide 1-38 have been reported to be encephalitogenic when adoptively transferred into naive syngeneic recipients. To determine whether the encephalitogenic epitope recognized by peptide 1-38-specific SJL T cells was different from those recognized by H-2u-restricted MBP peptide 1-38-specific T cells, peptide 1-38-specific SJL T cell lines were developed following immunization with guinea pig MBP peptide 1-38. Following a period of in vitro selection in the presence of peptide 1-38 and syngeneic antigen-presenting cells, one of two T cell lines transferred severe clinical disease adoptively.

Failure of (SJL/J x PL/J)F1 hybrid mice to develop immunologic tolerance to V beta 17a+ T cells results in F1 anti-SJL mixed lymphocyte reaction.

It has been reported previously that spleen cells from (SJL x PL) F1 hybrid mice are not tolerant to SJL parental cells as assessed by a one-way MLR. The possibility that the F1 anti-SJL reaction was due to the effect of lymphokines produced by the irradiated SJL T cells in response to I-Eu expressed on the F1 hybrid cells was eliminated since inclusion of anti-I-E mAb was without effect. Cell separations showed the responder cells to be plastic and nylon wool nonadherent Ia- T cells.

Suppressive activity of long-term myelin basic protein-specific SJL T cell lines.

Myelin basic protein (MBP)-specific T cell lines derived from SJL mice lose the ability to transfer adoptively experimental allergic encephalomyelitis (EAE) after 5-6 restimulations with antigen in vitro. In order to test whether such lines were suppressive, non-encephalitogenic T cell lines were co-cultured with a freshly derived encephalitogenic T cell line. Following co-culture in the presence of MBP and irradiated syngeneic spleen cells the mixture was transferred adoptively to syngeneic recipients.

Aplysia californica neurons R3-R14: primary structure of the myoactive histidine-rich basic peptide and peptide I.

The R3-R14 neurons of the marine mollusc Aplysia are neuroendocrine cells that express a gene encoding peptides I, II and histidine-rich basic peptide (HRBP), a myoactive peptide that excites Aplysia heart and enhances gut motility in vitro. Peptide II has been chemically characterized (35), but the complete primary structures of peptide I and HRBP have not been established by amino acid sequence analysis. HRBP, peptide I, and the prohormone (proHRBP) were therefore purified from acid extracts of Aplysia californica neural tissue using sequential gel filtration and reverse-phase high-performance liquid chromatography and chemically characterized.

Brown recluse spider bite. A literature review and case report.

A review of the literature on brown recluse spider bite is presented, including clinical presentation and treatment. Emphasis is placed on the treatment of local tissue necrosis. A case report of a severe necrotic ulcer secondary to a spider bit is presented.

Nutritional regulation of hepatic glucose-6-phosphate dehydrogenase. Transient activation of transcription.

Hepatic glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.

Distribution of rabbit mucosal glycoprotein throughout urinary tract.

The mucin layer covering the transitional epithelium of the bladder is thought to be an anti-adherence substance for bacteria. We describe the use of an immunoperoxidase staining technique to demonstrate the presence of glycoprotein lining the urothelium of both the upper and lower urinary tracts of the rabbit. Antisera against this glycoprotein (GP1) were raised in Swiss-Webster mice.

Cold exposure injuries: prevention and treatment.

A variety of cold exposure injuries were discussed, including frostnip, chilblains, trench foot, frostbite, and hypothermia. The usual precipitating factors for each were discussed along with the clinical course, the pathophysiology, and management from the perspective of one being in the field or backcountry. Prevention is the key to all cold-related problems as adequate treatment is often not possible out of the hospital setting.

Patterns of intra- and interspecific association of gall-forming sawflies in relation to shoot size on their willow host plant.

Four species of gall-forming sawflies were each frequently found to have clumped distributions among shoots within their willow host plant across four sites and three years. When all species were considered together by clone, year, and site, species showed independence of distribution among shoots two thirds of the time and showed positive covariance one third of the time. When pairs of species were considered separately, but clones were combined within sites and years, 60% of the chi-square tests of association were significant.

Variation in herbivore density among host plants and its consequences for community structure : Field studies on willow sawflies.

The densities of four species of gall-forming sawflies were found to vary significantly among willow host plant clones. Two of the speices varied among host plants at four sites in each of three years. The other two species varied in density among host plants at most of the sites in two of the three years.

Regulation of glucose-6-phosphate dehydrogenase by diet and thyroid hormone.

The regulation of hepatic glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.

Influence of the H-2u haplotype on immune function in F1 hybrid mice. II. F1 antiparent mixed lymphocyte reactivity.

Recently we reported that antigen-primed T cells from (H-2u X H-2s) F1 and (H-2u X H-2q)F1 mice responded poorly in vitro to antigen in the context of antigen-presenting cells of the non-H-2u parent. It was suggested that this effect might be due to unbalanced expression of parental antigens in the F1 hybrid with the result that the non-H-2u A antigens were greatly reduced or absent in these mice. If this were the case, non-H-2u Ia-A cells might be expected to stimulate a mixed lymphocyte reaction (MLR) when cultured with F1 responder cells.

Glucose-6-phosphate dehydrogenase mRNA sequence abundance in primary cultures of rat hepatocytes. Effect of insulin and dexamethasone.

Hepatic glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.

Studies on the mechanism of MPTP oxidation by human liver monoamine oxidase B.

The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its deuterated analogues were oxidized to their corresponding dihydropyridinium species (MPDP+) by preparations of pure human liver MAO B:monoclonal antibody complex to investigate the mechanism of MPTP activation. Lineweaver-Burk plots of initial reaction rates revealed that the Km,app values for the various deuterated MPTP analogues were similar to those of MPTP. In contrast, Vmax,app values were substantially decreased by substitution of deuterium for hydrogen on the tetrahydropyridinium ring, especially at C-6.

Platelet MAO concentration and molecular activity: I. New methods using an MAO B-specific monoclonal antibody in a radioimmunoassay.

New methods for determination of specific concentration and molecular activity of monoamine oxidase (MAO) in platelets are described and evaluated in parallel with specific activity measures, performed in whole platelets and platelet extracts. Platelet MAO specific concentration is determined in platelet extracts by a radioimmunoassay, using a monoclonal antibody that recognizes human MAO B, the form that occurs in platelets, but not MAO A. All four platelet MAO measures are found to be reliable and stable, and thus are suitable for long-term comparisons of normal and clinical populations, such as those reported in Part II of this report.