γ-Aminobutyric acid (GABA) and other amino acids in tissues of the tick,Amblyomma hebraeum (Acari: Ixodidae) throughout the feeding and reproductive periods

We assayed a variety of tick (Amblyomma hebraeum Koch; Acari, Ixodidae) tissues for a number of amino acids throughout the feeding and early reproductive periods. Our HPLC assay could detect as little as 2–5 pmol per sample of the following: GABA, glycine, serine, glutamine, alanine, taurine, glutamate and aspartate. All of these amino acids could be detected in the salivary gland, synganglion (=total CNS in acarines), haemolymph, Gené's organ, seminal receptacle and ovary. GABA reached high levels in the salivary gland of freshly engorged ticks (685 nmol g^-1) and in the synganglion it exceeded 1000 nmol g^-1 throughout most of the feeding cycle and the first week post-engorgement. GABA also reached a peak titre in the haemolymph of 40 nmol ml^-1. Taurine levels peaked at 1065 nmol g^-1 in the salivary gland from large partially fed ticks. Glutamate and aspartate were likewise found in the salivary gland and synganglion at high concentrations. For most of the amino acids there is insufficient information to correlate these titres (and fluctuations of titres) to neuromodulatory functions. It is possible, however, that the high GABA titre in the salivary gland of engorged ticks is correlated with an augmented level of fluid secretion.Deceased: Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9.     

The relative biological activities of α- and β-ecdysone and their 3 dehydro derivatives in the chromosome puffing assay

The relative biological activity of α- and β-ecdysone and their 3-dehydro derivatives in inducing changes in puffing activity in D. melanogaster salivary glands in vitro is approximately constant. Although the six different puffing assays differed considerably in their sensitivity to ecdysones, no stage-specific or locus-specific differential response to the four compounds was detected.     

Why Do the Karo Batak Prefer Women with Big Feet?

Men may find women with small feet relative to body size more attractive because foot size reliably indexes nubility—i.e., age and parity. I collected judgments of attractiveness in response to drawings of women with varying foot sizes from a sample of 159 Karo Batak respondents from North Sumatra, Indonesia, as part of a collaborative project on foot size and attractiveness. The data revealed a contrarian preference among the Karo Batak for women with big feet. The judgments were compared with the results of an existing cross-cultural study that found a preference for women with small feet in aggregate, but a mix of small- and large-foot preferences in the societies taken individually. Using contingency table analysis, I found that ecology and less exposure to Western media were associated with a preference for women with big feet; patriarchal values were not. The findings suggest that human mating preferences may arise in response to local ecological conditions, and may persist and spread via cultural transmission. This has implications for the concept of universality espoused in some versions of evolutionary psychology.     

Restricted plant species on sub-Antarctic Macquarie and Heard Islands

The recent distributional history of two Macquarie Island vascular plant species, Carex trifida, Poa litorosa, and the Heard Island vascular plant, Ranunculus crassipes is examined. C. trifida is known from only one small population on the north west coast of Macquarie Island. Four populations of P. litorosa were first recorded in the 1980s; we believe however, that it was first observed, but misidentified in the 1950s. R. crassipes was first discovered on Heard Island in the late 1980s. We argue that all three species are indigenous and arrived on their respective islands within the last 200 years by natural processes, most likely from warmer neighbouring islands, where these species have more extensive distributions. There have been small-scale changes in distribution of all species, mainly expansion. Further expansion of all three species is expected as a response to warming climate. Feral rabbit grazing is having a confounding negative influence on populations of P. litorosa.     

Editor’s note

Purinergic Signalling -     

Auxin-mediated induction of GAL promoters by conditional degradation of Mig1p improves sesquiterpene production in Saccharomyces cerevisiae with engineered acetyl-CoA synthesis

The yeast Saccharomyces cerevisiae uses the pyruvate dehydrogenase-bypass for acetyl-CoA biosynthesis. This relatively inefficient pathway limits production potential for acetyl-CoA-derived biochemical due to carbon loss and the cost of two high-energy phosphate bonds per molecule of acetyl-CoA. Here, we attempted to improve acetyl-CoA production efficiency by introducing heterologous acetylating aldehyde dehydrogenase and phosphoketolase pathways for acetyl-CoA synthesis to enhance production of the sesquiterpene trans-nerolidol. In addition, we introduced auxin-mediated degradation of the glucose-dependent repressor Mig1p to allow induced expression of GAL promoters on glucose so that production potential on glucose could be examined. The novel genes that we used to reconstruct the heterologous acetyl-CoA pathways did not sufficiently complement the loss of endogenous acetyl-CoA pathways, indicating that superior heterologous enzymes are necessary to establish fully functional synthetic acetyl-CoA pathways and properly explore their potential for nerolidol synthesis. Notwithstanding this, nerolidol production was improved twofold to a titre of ˜ 900 mg l⁻¹ in flask cultivation using a combination of heterologous acetyl-CoA pathways and Mig1p degradation. Conditional Mig1p depletion is presented as a valuable strategy to improve the productivities in the strains engineered with GAL promoters-controlled pathways when growing on glucose.     

The Design and Synthesis of N 4-Anthraniloyl-2′-dC,the Improved Syntheses of N 4-Carbamoyl-and N4- Ureidocarbamoyl-2′-dC,Incorporation into Oligonucleotides and Triplex Formation Testing

Abstract

Three modified nucleosides were designed with the aim of achieving triplet formation with the CG base pair of duplex DNA. Direct anthraniloylation of 2′-deoxycytidine, using isatoic anhydride, afforded the novel N ⁴-anthraniloyl-2′-deoxycytidine. Much improved preparations of N ⁴-carbamoyl-2′-deoxycytidine and of N ⁴-ureidocarbonyl-2′-deoxycytidine were accomplished. The modified nucleosides were incorporated into oligonucleotides. Thermal denaturation studies and gel mobility shift analysis suggest that these nucleosides do not form base triplets with any of the four base pairs of DNA.