Seasonal variation in the growth and nutrient content of yellow-birch replacement roots

Summary Modified air layers were established on lateral long roots of 9 yellow birch (Betula alleghniensis Britton) trees, and all replacement roots >. 5 cm long were harvested periodically during the 1971 and 1972 growing seasons. The first replacement roots grew 6 weeks after layer establishment. Root layers were inactive from 29 Oct. 71 to 5 May 72. Active root layers produced an average of 208 mg per tree during the first season and 198 mg per tree during the second season. Concentrations of N, P, K, Ca, Mg, Fe, Mn, Zn, and Al all varied within growing season, and average concentration of some elements—Ca in particular—varied between growing seasons. This technique shows promise for studying the nutrient status of root systems of forest trees.     

Properties of rat liver microsomal stearoyl-coenzyme A desaturase.

1. Rat liver microsomal stearoyl-CoA desaturase activity was shown to be stimulated by both bovine serum albumin and a basic cytoplasmic protein from rat liver. 2. Partially purified desaturase is unaffected by either of these two proteins. 3. Bovine serum albumin appears to exert its effect on the crude system by protecting the desaturase substrate, stearoly-CoA, from the action of endogenous thiolesterases. 4. By using partially purified enzyme preparations, it was possible to establish the substate specificity of the delta9-fatty acyl-CoA desaturase with the C14, C15, C16, C17, C18 and C19 fatty acyl-CoA substrates. Maximum enzyme activity was shown with stearoyl-CoA decreasing with both palmitoyl-CoA and nonadecanoyl-CoA, as reported previously for free fatty acids. 5. Both cytochrome b5 and NADH-cytochrome b5 reductase (EC 1.6.2.2) are required for these studies and a method is described for the purification of homogeneous preparations of detergent-isolated cytochrome b5 from rat liver. 6. From amino acid analyses, a comparison was made of the hydrophobicity of the membrane portion of cytochrome b5 with the hydrophobicity reported for stearoyl-CoA desaturase. The close resemblance of the two values suggested that unlike cytochrome b5 and its reductase, the stearoyl-CoA desaturase may be largely buried in the endoplasmic reticulum.     

Avian biodiversity in the coastal wetlands of the Okahukura Peninsula

The Tapora Landcare Group, operating on the Okahukura Peninsula, has the long-term goal of making this region predator fenced. The aim of this study was to obtain information on the current status of avian biodiversity and the bird community across the band of coastal wetlands on the Okahukura Peninsula. Bird counts were conducted and playback lures used to detect three cryptic wetland species: fernbirds (Bowdleria punctata); spotless crakes (Porzana tabuensis); and banded rails (Gallirallus philippensis). Fernbirds and banded rails were detected at seven of the eight wetland sites sampled whereas spotless crakes were detected at two sites. The native species with the highest relative abundance across the eight sites were silvereyes (Zosterops lateralis) and South Island pied oystercatchers (Haematopus finschi). Changes in avian biodiversity over time in the region can now be monitored, and comprehensive long-term data on the status of avian biodiversity over time obtained.     

The annual cycle and breeding behaviour of the Mauritius Fody Foudia rubra

Safford, R.J. 1997. The annual cycle and breeding behaviour of the Mauritius Fody Foudia rubra. Ostrich 68 (24): 58–67.

The Mauritius Fody Foudia rubra, a highly endangered species of weaver (Ploceidae) endemic to Mauritius, was studied from 1989–1993. The plumage, various display postures (typical of the family), and seven adult and two juvenile vocalisations are described. The diet consisted of insects, nectar and fruit. Males were in breeding plumage, and breeding took place, between late August and early April, although severe weather in February 1992 terminated breeding activity early. The species appeared to be monogamous and was suspected to maintain a long-term pair bond. Pairs occupied exclusive territories of not less than 0.9 ha. Both sexes built the nest from the outset, but only the female lined it. Between breeding attempts, some pairs habitually started but then abandoned one or more nests. Clutch sizes of two to four were recorded, three being the norm. Incubation and brooding were carried out by the female; the male joined in feeding the young after daytime brooding ceased. Juvenile dependency appeared to last around two weeks after which the young were ousted from the territory. The potential productivity of up to three broods per pair per year was not achieved by any pair studied because of poor nesting success. A complete moult followed breeding. Territorial defence continued throughout the year, and no evidence for seasonal movements was seen. Two behavioural features seem unexpected: 1) male nest invitation and nest advertisement behaviour appeared to be absent; 2) females participated from the outset of nest-building (including prospecting). These could be explained by the existence of a long-term pair bond, which needs to be confirmed but would not be surprising in a species that remains on territory all year. Hypotheses that could be tested to find a mechanism responsible for the unusual features of the fody are suggested. In comparison with other fodies studied, the breeding behaviour most resembled that of the Seychelles Fody F. sechellarum (also a monogamous, non-graminivorous omnivore that breeds in solitary pairs in evergreen forest). The annual cycle was similar to that of other native passerines and most other fody taxa.     

Neurogenic differentiation of murine and human adipose-derived stromal cells

The identification of cells capable of neuronal differentiation has great potential for cellular therapies. We examined whether murine and human adipose-derived adult stem (ADAS) cells can be induced to undergo neuronal differentiation. We isolated ADAS cells from the adipose tissue of adult BalbC mice or from human liposuction tissue and induced neuronal differentiation with valproic acid, butylated hydroxyanisole, insulin, and hydrocortisone. As early as 1-3 h after neuronal induction, the phenotype of ADAS cells changed towards neuronal morphology. Following neuronal induction, muADAS cells displayed immunocytochemical staining for GFAP, nestin and NeuN and huADAS cells displayed staining for intermediate filament M, nestin, and NeuN. Following neuronal induction of murine and human ADAS cells, Western blot analysis confirmed GFAP, nestin, and NeuN protein expression. Pretreatment with EGF and basic FGF augmented the neuronal differentiation of huADAS cells. The neuronal differentiation of stromal cells from adipose tissue has broad biological and clinical implications.     

Immunological detection of NADH-specific enoyl-ACP reductase from rape seed (Brassica napus)--induction, relationship of alpha and beta polypeptides, mRNA translation and interaction with ACP

An antibody has been raised against rape seed enoyl-ACP reductase. This recognizes both the alpha and beta polypeptides of the enzyme. Immunoblotting of fresh seed demonstrates that beta is not present in seed material, and that it is produced by proteolysis during isolation. It is thus deduced that rape seed enoyl reductase is an alpha 4 homotetramer. Leaf material from both rape and Arabidopsis have an enoyl reductase with a similar electrophoretic mobility to the rape seed enzyme when analyzed on SDS-PAGE. Quantitative immunoassay has demonstrated that the enzyme continually increases during lipid deposition, indicating that an increase in this enzyme is required to sustain high levels of lipid biosynthesis. In vitro translation experiments show that the enzyme is nuclear coded and synthesized as a precursor form. Immunogold electron microscopy has demonstrated that enoyl reductase is located in plastids. It is shown that ACP-Sepharose may be used as a matrix in the purification of enoyl-ACP reductase.