Allison Knight

Will loss of snow cover during climatic warming expose New Zealand alpine plants to increased frost damage

If snow cover in alpine environments were reduced through climatic warming, plants that are normally protected by snow-lie in winter would become exposed to greater extremes of temperature and solar radiation. We examined the annual course of frost resistance of species of native alpine plants from southern New Zealand that are normally buried in snowbanks over winter (Celmisia haastii and Celmisia prorepens) or in sheltered areas that may accumulate snow (Hebe odora) and other species, typical of more exposed areas, that are relatively snow-free (Celmisia viscosa, Poa colensoi, Dracophyllum muscoides). The frost resistance of these principal species was in accord with habitat: those from snowbanks or sheltered areas showed the least frost resistance, whereas species from exposed areas had greater frost resistance throughout the year. P. colensoi had the greatest frost resistance (−32.5°C). All the principal species showed a rapid increase in frost resistance from summer to early winter (February–June) and maximum frost resistance in winter (July–August). The loss of resistance in late winter to early summer (August–December) was most rapid in P. colensoi and D. muscoides. Seasonal frost resistance of the principal species was more strongly related to daylength than to temperature, although all species except C. viscosa were significantly related to temperature when the influence of daylength was accounted for. Measurements of chlorophyll fluorescence indicated that photosynthetic efficiency of the principal species declined with increasing daylength. Levels of frost resistance of the six principal alpine plant species, and others measured during the growing season, were similar to those measured in tropical alpine areas and somewhat more resistant than those recorded in alpine areas of Europe. The potential for frost damage was greatest in spring. The current relationship of frost resistance with daylength is sufficient to prevent damage at any time of year. While warmer temperatures might lower frost resistance, they would also reduce the incidence of frosts, and the incidence of frost damage is unlikely to be altered. The relationship of frost resistance with daylength and temperature potentially provides a means of predicting the responses of alpine plants in response to global warming.

Surface-Active Fungicidal d-Peptide Inhibitors of the Plasma Membrane Proton Pump That Block Azole Resistance

ABSTRACT A 1.8-million-member d-octapeptide combinatorial library was constructed in which each member comprised a diversity-containing N-terminal pentapeptide and a C-terminal amidated triarginine motif. The C-terminal motif concentrated the library members at the fungal cell surface. A primary screen for inhibitors of Saccharomyces cerevisiae and Candida albicans growth, together with an in vitro secondary screen with the S. cerevisiae plasma membrane ATPase (Pma1p) as a target, identified the antifungal d-octapeptide BM0 (d-NH2-RFWWFRRR-CONH2). Optimization of BM0 led to the construction of BM2 (d-NH2-RRRFWWFRRR-CONH2), which had broad-spectrum fungicidal activity against S. cerevisiae, Candida species, and Cryptococcus neoformans; bound strongly to the surfaces of fungal cells; inhibited the physiological activity of Pma1p; and appeared to target Pma1p, with 50% inhibitory concentrations in the range of 0.5 to 2.5 μM. At sub-MICs (<5 μM), BM2 chemosensitized to fluconazole (FLC) S. cerevisiae strains functionally hyperexpressing fungal lanosterol 14α-demethylase and resistance-conferring transporters of azole drugs. BM2 chemosensitized to FLC some FLC-resistant clinical isolates of C. albicans and C. dubliniensis and chemosensitized to itraconazole clinical isolates of C. krusei that are intrinsically resistant to FLC. The growth-inhibitory concentrations of BM2 did not cause fungal cell permeabilization, significant hemolysis of red blood cells, or the death of cultured HEp-2 epithelial cells. BM2 represents a novel class of broad-spectrum, surface-active, Pma1p-targeting fungicides which increases the potencies of azole drugs and circumvents azole resistance.

Graves’ Disease a Paradigm For Autoimmunity

The presence of iodine atoms in thyroid hormone has proved to be fortunate for man in enabling him to understand great principles of the diseases which plague him. Dietary deficiency of iodine, leading to spectacular goitres, drew attention to the thyroid and the success of surgeons in extirpating goitres founded the study of endocrinology by showing that the thyroid secretes a product which is necessary for health and readily available from simple preparations of animal tissue 1.

Conservation status of New Zealand lichens

Abstract The first listing of the conservation status of lichens indigenous to the New Zealand Botanical Region (excluding Macquarie Island) is presented. The list comprises 1799 formally accepted taxa placed in the following categories: ‘Threatened’, 11 taxa (comprising 4 taxa Nationally Critical, 4 Nationally Endangered, 3 Nationally Vulnerable); ‘At Risk’, 176 taxa (comprising 173 Naturally Uncommon and 4 Declining taxa); and 975 ‘Data Deficient’ taxa. A further 636 taxa were considered ‘Not Threatened’. A further five lichens are listed as ‘Taxonomically Indeterminate’, being lichens which may warrant further conservation attention once their taxonomic status is clarified. A concordance of lichen names is provided. A brief analysis of the patterns of threat and rarity exhibited by New Zealand lichens listed is also presented.

Development of Vascular Reactivity in Chickens: Responses of Mesenteric and Hind-Limb Blood Vessels to Norepinephrine and Acetylcholine

Mesenteric arteries and the hind-limb vasculature supplied by the sciatic artery were isolated from chickens 0–25 vity days after hatching and perfused with physiological saline. Mesenteric arteries gave only small responses to norepinephrine until the 2nd week after hatching when there was a striking increase in their reactivity. Hind-limb blood vessels were much more responsive to norepinephrine from the 1st day. The height of vasoconstrictor responses in hind-limbs showed no marked change with age but the duration of responses decreased as chickens grew older. The duration of responses to norepinephrine increased when perfusion temperature was lowered from 40 to 20 °C. Acetylcholine produced vasodilatation in mesenteric and hind-limb blood vessels. It is concluded that the receptor mechanisms for adrenergic and cholinergic control of hind-limb blood flow are functional at or before hatching. The increase in vascular reactivity to norepinephrine in mesenteric arteries coincides with reported increases in blood pressure and thermoregulatory ability of chickens and may contribute to these increases.

Antiseptal autoantibodies in schizophrenia.

240 mg daily) and report no side effects from the medication. Both report also that their speech continues to be better than it has been for as long as they can remember. They report also that failure to take the verapamil for a day or so (e.g., forgetting to do so, temporarily running out of the medication) is followed by a return of more stuttering. Their rates of dysfluency while reading a 1000 syllable story (RD) and speaking extemporaneously for 3 min (SD) are given in Table 1 along with the corresponding dysfluency rates on initial (baseline) testing and at the 6-month follow-up. The results we published in 1989 are more modest