Rat brain Na channel mRNAs in non-excitable Schwann cells

The expression of rat brain voltage-sensitive Na⁺ channel mRNAs in Schwann cells was examined using in situ hybridization cytochemistry and RT-PCR. The mRNAs of rat brain Na⁺ channel subtype II and III, but not subtype I, were detected in cultured Schwann cells from sciatic nerve and in intact sciatic nerve, which contains Schwann cells but not neuronal cell bodies. These results indicate that rat brain Na⁺ channel mRNAs, which have been considered as mainly neuronal-type messages, are also expressed in glial cells in vitro and in vivo.     

A mating-type factors of Coprinus cinereus have variable numbers of specificity genes encoding two classes of homeodomain proteins

We have identified the seven genes that constitute the A43 mating-type factor of Coprinus cinereus and compare the organisation of A43 with the previously characterised A42 factor. In both, the genes that trigger clamp cell development, the so-called specificity genes, are separated into and loci by 7 kb of noncoding sequence and are flanked by homologous genes -fg and -fg. The specificity genes are known to encode two classes of dissimilar homeodomain (HD1 and HD2) proteins and have different allelic forms which show little or no cross-hybridisation. By partial sequencing we identified a divergently transcribed HD1 (a1-2) and HD2 (a2-2) gene in the A43 locus. a2-2 failed to elicit clamp cell development in three different hosts, suggesting that it is non-functional. a1-2 elicited clamp cells in an A42 host that has only an HD2 gene (a2-1) in its locus, thus demonstrating that the compatible A mating interaction is between an HD1 and an HD2 protein. The A43 locus contains three specificity genes, the divergently transcribed HD1 and HD2 genes b1-2 and b2-2 and a third HD1 gene (d1-1) that was shown by hybridisation and transformation analyses to be functionally equivalent to d1-1 in A42. An untranscribed footprint of a third A42 HD1 gene, c1-1, was detected between the A43 b2-2 and d1-1 genes by Southern hybridisation.     

Drought response of a native and introduced Hawaiian grass

The alien grass, Pennisetum setaceum, dominates many of the lowland arid regions that once supported native Heteropogon contortus grassland on the island of Hawaii. Response to drought in a glasshouse was compared between these C₄ grasses to test if success as an invader is related to drought tolerance or plasticity for traits that confer drought tolerance. Pennisetum produced 51% more total biomass, allocated 49% more biomass to leaves, and had higher net photosynthetic rates (P _n) on a leaf area basis than Heteropogon. Plants of both species under drought produced less total biomass and increased their allocation to roots compared to well-watered plants, but there was no difference between the two species in the magnitude of these responses. The decline in P _n with decreasing leaf water potential (₁) was greater for Pennisetum compared to Heteropogon. Plasticity in the response of P _n to ₁, osmotic potentials, and the water potentials at turgor loss in response to drought were not different between the two species. Stomata were more responsive to w in Heteropogon than in Pennisetum and for well-watered plants compared to droughted plants. Plasticity for the stomatal response to w, however, was not different between the species. There was no evidence that the alien, Pennisetum, had greater plasticity for traits related to drought tolerance compared to the native, Heteropogon. Higher P _n and greater biomass allocation to leaves resulted in greater growth for Pennisetum compared to Heteropogon and may explain the success of Pennisetum as an invader of lowland arid zones on Hawaii.     

Growth rates in outbreak populations of the corallivorous gastropod Drupella cornus (Röding 1798) at Ningaloo Reef,Western Australia

Mark and recapture experiments were used to estimate the size-at-age relationship of the coral-eating gastropod Drupella cornus at Ningaloo Reef, Western Australia. Animals 15 mm long increased in length by 5.2 mm in six months at a site in an early stage of an outbreak, but by only 3.8 mm at a site within an established outbreak. Snails larger than 35 mm grew very little. Based on observed growth rates fitted to a Richards function growth equation, snails 28 mm long judged to be reproductively mature would be 2.5 to 3.5 years old, suggesting that local outbreaks represent no more than one or two generations of recruits. Indirect evidence indicates that growth is more rapid in the earlier than in later stages of outbreaking populations. The growth and timing of life-history transitions of D. cornus are not unusual among other muricid species.     

HPLC and NMR methods for the quantitation of the (R)-enantiomer in (−)-(S)-timolol maleate drug raw materials

HPLC and ¹H-NMR methods for the quantitation of the (R)-enantiomer in (?)-(S)-timolol maleate were developed and validated. The HPLC method requires a 25 cm × 4.6 mm 5 μm Chiracel OD-H (cellulose tris-3,5-dimethylphenylcarbamate) column, a mobile phase of 0.2% (v/v) diethylamine and 4% (v/v) isopropanol in hexane at a flow rate of 1 ml/min and UV detection at 297 nm. A system suitability test was devised to verify the separation of the (R)- and (S)-enantiomers of timolol from other drug-related impurities. The NMR method requires the use of a high-field NMR spectrometer (>360 MHz) and a chiral solvating agent, (?)-(R)-2,2,2-trifluoro-1-(9-anthrylethanol) (R-TFAE). The limits of quantitation were 0.05% and 0.2% (m/m) for HPLC and NMR, respectively. The methods were applied to the determination of the (R)-enantiomer in eight lots of raw material. The results for the two methods were in very good agreement, with results ranging from 0.1 to 4.1% (m/m) by HPLC and none detected to 4.3% (m/m) by NMR. The USP method for specific rotation was found to be unsuitable for detecting the presence of low levels of the (R)-enantiomer in (?)-(S)-timolol maleate. © 1994 Wiley-Liss, Inc.     

Immature mouse uterine tissue in organ culture: Estrogen-induced growth,morphology and biochemical parameters

Summary Although estrogens have been shown to stimulate a variety of morphologic and biochemical changes in the uterus in vivo, no clear consistent demonstration of similar responses in vitro have been made; thus, a defined organ culture system using the immature mouse uterus was established to study the possibility of demonstrating estrogenic responses in vitro. Uterine tissue from immature outbred mice (17 to 24 days of age) were cut crosswise in 1-mm³ coins and cultured in a defined medium in the absence of serum, phenol red, or growth factor supplements. Diethylstilbestrol (DES), a synthetic estrogen, was added to the media at doses ranging from 1 to 100 ng/ml. The effect of DES on uterine cell proliferation was assessed by morphologic changes in uterine epithelial and stromal cells, increase in number of epithelial cells per unit basement membrane, increase in height of luminal epithelial cells, and [³H]thymidine incorporation. Functional changes were determined by measuring the amounts of the estrogen-inducible uterine protein, lactoferrin, that was localized in the epithelial cells and secreted into the media, and the localization of the estrogen receptor in the cultured tissues. Results indicate that under the described conditions of culture, estrogens like DES can induce morphologic and biochemical responses in the uterus that are similar to those seen in vivo. This organ culture system will aid in the investigation of various mechanisms involved in the hormonal regulation of growth and differentiation of estrogen target tissues.     

A somatic cell hybrid map of the long arm of human chromosome 17, containing the familial breast cancer locus (BRCA1).

We describe a detailed somatic cell hybrid map of human chromosome 17q11.2-q23, containing the familial breast and ovarian cancer locus (BRCA1) and highly informative closely linked markers. An X-irradiation panel of 38 hamster/human and mouse/human hybrids with fragments of chromosome 17 was generated and characterized with 22 STS markers from this chromosome. A detailed map of 61 probes onto chromosome 17q, subdividing the chromosome arm into 25 regions, was done by using a panel of hybrids with well-defined breakpoints and nine chromosome-mediated gene transfectants. Our localization of RARA, TOP2, EDH17B1 and 2, and possibly WNT3, between THRA1 and D17S181, two markers known to flank BRCA1, suggests that any of these is a potential candidate for the BRCA1 locus. The marker D17S579 (Mfd188), which is believed to be very close to BRCA1, maps closest to the EDH17B genes.     

Ozone inactivation of Cryptosporidium parvum in demand-free phosphate buffer determined by in vitro excystation and animal infectivity.

Inactivation of Cryptosporidium parvum oocysts by ozone was performed in ozone demand-free 0.05 M phosphate buffer (pH 6.9) in bench-scale batch reactors at 7 and 22 degrees C. Ozone was added to each trial from a concentrated stock solution for contact times ranging from 5 to 15 min. The viability of the control and treated oocysts was determined by using in vitro excystation and infection in neonatal CD-1 mice. It was found that excystation consistently underestimated inactivation when compared with animal infectivity (P < or = 0.05). As inactivations increased, the difference between excystation and infectivity also increased. The inactivation kinetics of C. parvum by ozone deviated from the simple first-order Chick-Watson model and was better described by a nonlinear Hom model. The use of the Hom model for predicting inactivation resulted in a family of unique concentration and time values for each inactivation level rather than the simple CT product of the Chick-Watson model.     

Managing lepidopteran pests in cabbage with herbicide-induced resistance, in combination with a pyrethroid insecticide

S-ethyldipropylthiocarbamate (EPTC) applied as a soil treatment or over-the-top spray on cabbage plants (Brassica oleracea L.) caused the leaves to turn ‘glossy’ for as long as 30 days. EPTC-induced glossy plants were damaged significantly less than untreated plants by diamondback moth,Plutella xylostella (L.), imported cabbage worm,Pieris rapae (L.), and cabbage looper,Trichoplusia ni (Hbn.). Reductions in damage were equivalent to those obtained from treatment with permethrin. When used in combination with permethrin, EPTC provided additive control of damage by these pests. Our calculations show EPTC-induced resistance to be cost-effective. This use of EPTC has several limitations, however. Younger plants (<9 leaves) were killed or injured by the herbicide. The growth of older plants was not affected, but plants did not become glossy for ca. 10 days after they were treated with EPTC. The crop must be protected with insecticides until the plants are mature enough to treat with EPTC, and until treated plants become glossy. In addition, since the glossy trait is only effective against first instar larvae, populations of later instars on glossy plants must be reduced with an application of insecticide. Finally, EPTC formulations are water-soluble and can be washed away from the plants by heavy rains and irrigation, which may make this use of EPTC impractical in some situations. Where its use is practical, and the indicated precautions are taken, EPTC-induced resistance could reduce dependence on chemical insecticides and reduce selection for insecticide resistance in diamondback moth.