P0 promoter directs expression of reporter and toxin genes to Schwann cells of transgenic mice.

We generated transgenic mice that specifically express foreign genes in myelinating Schwann cells. A 1.1 kb segment of 5' flanking sequence from the rat P0 gene was used to drive expression of the genes encoding human growth hormone (hGH) and bacterial diphtheria toxin A chain (DT-A). The P0-hGH mice expressed hGH in myelinating Schwann cells, but not in nonmyelinating Schwann cells, the central nervous system, or any other tissue assayed. This expression was activated on a developmental schedule comparable to that of endogenous myelin gene expression. One line of P0-DT-A mice developed a generalized hypomyelinating peripheral neuropathy, with Schwann cell deficiency apparent in newborn animals. Peripheral nerves from adult mice of this line displayed morphological alterations ranging from completely denuded axons to myelinated Schwann cells undergoing degeneration, although occasional Schwann cells were able to form apparently normal myelin sheaths. Pronounced secondary changes, including proliferation and retraction of processes, occurred in the nonmyelinating Schwann cells of these P0-DT-A mice.     

A novel modification of the avidin-biotin complex method for immunohistochemical studies of transgenic mice with murine monoclonal antibodies.

When mouse tissues are probed with murine monoclonal antibodies (MAb) by indirect immunohistochemistry, the secondary antibody detects tissue-bound MAb and irrelevant, endogenous mouse immunoglobulins. The latter are a source of confounding background, especially in diseased tissues. To circumvent this problem, we generated complexes of primary MAb and biotinylated secondary antibodies in vitro for use as antigen-specific probes. After blocking free binding sites in the complexed secondary antibodies with normal mouse serum, the complexes were applied to mouse tissue sections and tissue-bound complexes were visualized with an avidin-biotin detection system. Complexes formed with 12 different rat or mouse MAb were used to probe sections of normal mice, tumor-bearing transgenic mice, and mice with tumor xenografts. The staining patterns produced by these probes reflected the specificity of the MAb in the complexes, and the labeling of irrelevant, endogenous mouse immunoglobulins was reduced substantially. This novel, indirect immunohistochemical method can be exploited to study normal and diseased mouse tissues using a variety of murine MAb.     

Chronic ethanol exposure increases levels of protein kinase C delta and epsilon and protein kinase C-mediated phosphorylation in cultured neural cells.

Exposure to ethanol for several days increases the number and function of dihydropyridine-sensitive Ca2+ channels in excitable tissues. In the neural cell line PC12, this process is blocked by inhibitors of protein kinase C (PKC), suggesting that PKC mediates ethanol-induced increases in Ca2+ channels. We report that treatment with 25-200 mM ethanol for 2-8 days increased PKC activity in PC12 cells and NG108-15 neuroblastoma-glioma cells. Detailed studies in PC12 cells showed that ethanol also increased phorbol ester binding and immunoreactivity to PKC delta and PKC epsilon. These changes were associated with increased PKC-mediated phosphorylation. Ethanol did not activate the enzyme directly, nor did ethanol increase levels of diacylglycerol. Ethanol-induced increases in PKC levels may promote up-regulation of Ca2+ channels, and may also regulate the expression and function of other proteins involved in cellular adaptation to ethanol.     

Ripeness effects of three vegetable crops on abundance of augmentatively released psyttalia fletcheri (Hym.: Hraconidae): Improved sampling and release methods

Studies were done to determine the effect of 4 fruit ripeness levels on the abundance of Psyttalia fletcheri (Silvestri),a parasitoid of Bactrocera cucurbitae (Coquillett). In addition,an improved trapping method was developed for monitoring massreleased adult parasitoids in the field. A total of 420,000 adult P. fletcheri were released over a period of 15 weeks,in a 0.16 ha experimental field plot containing cucumber,zucchini and tomato in Kauai,HI. We recovered significantly more P. fletcheri from rotting fruits of all fruit types than from immature,commercial grade or oversized fruits. In addition,there was a positive correlation between the number of P. fletcheri and B. cucurbitae recovered from rotting fruits. Average parasitism in rotting tomato,zucchini and cucumber was 5,19 and 36% respectively. Yellow pan traps were as effective as sticky sphere traps for monitoring P. fletcheri,indicating that parasitoids were foraging close to the ground where rotting fruits occurred. The pan traps were much easier to use,less expensive and required less set up time. Recovery of parasitoids from both fruit collections and pan traps indicated that P. fletcheri was least abundant in tomato. Both male and female parasitoids exhibited a weakly aggregated distribution in each crop. We discuss modified sampling and release methods for population estimation and augmentative release studies of P. fletcheri.     

Proline-rich-protein promoters direct LacZ expression to the granular convoluted tubular cells of the submandibular gland in adult transgenic mice

The ability of two mouse PRP gene promoters to direct the expression of the bacterial lacZ reporter gene was tested in transgenic mice. Transgenes A1-lacZ and C1-lacZ consisted of 8.2 kb A1 and 7.8 kb C1 PRP promoters respectively fused to the lacZ coding sequence. A1 and C1 are two A-type PRP genes isolated from the inbred SWR mice, which show the same gene structure and similar sequence to the closely related MP2 and M14 PRP genes previously cloned from outbred CD-1 mice. We here show that both A1-lacZ and C1-lacZ transgenes have very similar expression patterns: (1) they expressed the lacZ gene in all 14 established transgenic lines under normal (non-stimulated) conditions; (2) the expression was restricted to the granular convoluted tubular cells of the submandibular glands; (3) the expression was developmentally regulated beginning at sexual maturation and lasting to at least 1.5 years of age; and (4) expression in some lines was probably influenced by sex hormones, since higher expression was found in males than in females. A1-lacZ and C1- lacZ are the first transgenes derived from the PRP/GRP (glutamine/glutamic acid-rich protein) gene superfamily to be expressed in the granular convoluted tubular cells (with known endocrine functions), rather than in the acinar cells (with mainly exocrine functions) of the submandibular glands     

Apple II software for M13 shotgun DNA sequencing.

A set of programs is presented for the reconstruction of a DNA sequence from data generated by the M13 shotgun sequencing technique. Once the sequence has been established and stored other programs are used for its analysis. The programs have been written for the Apple II microcomputer. A minimum investment is required for the hardware and the software is easily interchangeable between the growing number of interested researchers. Copies are available in ready to use form.     

Applications of fluorophore-containing microbial growth media.

Media containing the fluorogenic compound 8-anilino-1-naphthalene sulfonic acid may be used to discriminate between gram-positive and gram-negative bacteria and to differentiate between various species of bacteria. Fluorescent light emitted from colonies of gram-negative bacteria on 8-anilino-1-naphthalene sulfonic acid-containing agar was visually more intense than that on gram-positive bacteria. The emitted light from the gram-negative bacteria differed in wave-lengths from that of light emitted by colonies of gram-positive bacteria. The fluorescent intensity of colonies on complete 8-anilino-1-napthalene sulfonic acid agar supplemented with 1% of single substrates varied depending on the bacterial species, thus allowing the development of profiles used to identify 12 different species.     

Alterations in Dihydromorphine Binding in Cerebral Hemispheres of Aged Male Rats

Equilibrium binding of [3H]dihydromorphine was assayed in brain regions of young and aged male F344 rats. Young rats had significantly higher receptor densities than old rats in the frontal poles, anterior cortex, and striatum. In the frontal poles, the decline in receptor concentration with age was accompanied by a significant increase in the apparent affinity of dihydromorphine for receptors, which may be compensatory for the decrease in Bmax. This pattern of receptor alterations is different than that previously observed in aged female rats. Therefore, processes which underlie synaptic alterations with age may be different in males and females.     

Effects of humidity on eggs and immatures of Neoseiulus fallacis,Amblysieus andersoni,Metaseiulus occidentalis and Typhlodromus pyri (Phytoseiidae): implications for biological control on apple,caneberry, strawberry and hop

The lethal humidity (LH₅₀) responses at 20°C of eggs of two strains of Neoseiulus fallacis (Garman) were 71.6 and 69.7%; of three strains of Amblyseius andersoni (Chant) were 62.9, 62.0 and 62.4% and of one strain each of Typhlodromus pyri Scheuten and Metaseiulus occidentalis Nesbitt were 55.0 and 28.4%, respectively. Eggs of three genetically distinct strains of A. andersoni from Oregon, the Netherlands and Italy did not respond differently from one another nor did eggs of freely hybridizing N. fallacis from Michigan and Oregon. Mortality of larvae through development to early protonymphs at 50% RH, 20°C. was 91.9, 82.3, 46.2 and 31.0% for fed mites and 98.1, 83.2, 67.0 and 89.7% for unfed mites of Oregon strains of N. fallacis, A. andersoni, T. pyri and M. occidentalis, repectively. Fed larvae-protonymphs of M. occidentalis and T. pyri were more tolerant of low humidity than fed larvae-protonymphs of N. fallacis and A. andersoni. Mortality was less for fed than unfed larvae-protonymphs of M. occidentalis and T. pyri, but there were no differences for A. andersoni and N. fallacis. Levels of feeding by predator larvae on T. urticae and cannibalism by phytoseiid protonymphs contributed to species differences. Responses to humidity are discussed in relation to geographic and host plant distributions and biological control by single or mixed species populations of phytoseiids.