Monstrilloida (Copepoda) off the Brazilian coast

Seven monstrilloid species of the genera Thaumaleus and Monstrilla (Copepoda) are reported from the Brazilian coast. Occurrence, distribution and ecological information is given for: T. longispinosum, T. rigidum, T. quadridens, M. recticulata, M. grandis, M. dubia and M. rugosa.     

Protein polymorphism inEligmodontia typus. Genetic divergence with other phyllotine cricetids

By means of gel electrophoresis of tissue extracts we have studied protein polymorphism inEligmodontia typus. The analysis was performed on specimens from five population samples collected at different sites in Patagonia (Argentina). Mean heterozygosity (\-h) and proportion of polymorphic loci (P) were determined on the basis of 19 loci. Considering all individuals as one sample, \-h gave a value of 0.16 and P was 70%. Although these values are much higher than those reported for most rodent species, they are very similar to those obtained by us for four species of the genusCalomys and forGraomys griseoflavus. There is a striking genetic identity (I_N=0.99) among populations from regions with different environmental conditions, indicating that the species possesses a common genic pool. Genetic distance with other species of the Phyllotini was estimated. D_N was lower betweenE. typus andCalomys (mean D_N=0.88) than betweenE. typus andGraomys griseoflavus (D_N=1.01). The high morphological similarity between these last two species, especially regarding those characters related to desert life adaptation, could be assigned, at least in part, to convergent evolution.     

Decomposition of Eucalyptus globulus leaves and three native leaf species (Alnus glutinosa, Castanea sativa and Quercus faginea) in a Portuguese low order stream

Leaf decomposition of the exotic evergreen Eucalyptus globulus (eucalyptus), and three native deciduous tree species, Alnus glutinosa (alder), Castanea sativa (chestnut) and Quercus faginea (oak), was compared in a second order stream in Central Portugal. Changes in dry weight, nitrogen and polyphenolic compounds and microbial colonization were periodically assessed for three months.Negative exponential curves fit the leaf weight loss with time for all leaf species. Mass loss rate was in the order alder (K = 0.0161) > chestnut (K = 0.0079) > eucalyptus (K = 0.0068) > oak (K = 0.0037). Microbial colonization followed the same pattern as breakdown rates. Evidence of fungal colonization was observed in alder after 3 days in the stream, whereas it took 21 days in oak leaves to have fungal colonization. Fungal diversity was leaf species-dependent and increased with time. In all cases, percent nitrogen per unit leaf weight increased, at least, at the initial stages of decay while soluble polyphenolics (expressed as percentage per unit leaf weight) decreased rapidly in the first month of leaves immersion.Intrinsic factors such as nitrogen and polyphenolic content may explain differences in leaf decomposition. The possible incorporation of eucalyptus litter into secondary production in a reasonable time span is suggested, although community balance and structure might be affected by differences in allochthonous patterns determined by eucalyptus monocultures.     

Linkage disequilibrium analysis in Machado-Joseph disease patients of different ethnic origins

Machado-Joseph disease (MJD) is an autosomal dominant spinocerebellar degeneration originally described in families of Portuguese-Azorean ancestry. The hypothesis that its present world distribution could result from the spread of an original founder mutation has been raised. To test this possibility we have conducted a linkage disequilibrium study of markers segregating with the MJD1 locus in a total of 64 unrelated families of different geographical origins. Significant association was detected between the MJD1 locus and marker alleles at loci D14S280, D14S1050 and D14S81. All affected individuals, except one Chinese family, had allele 3 (237 bp) at D14S280. This finding is consistent with a founder effect in our MJD population. However, distinct haplotypes were observed in patients originating from the two Azorean islands showing the highest disease prevalence; therefore, the possible existence of more than one founder mutation can not be excluded with the markers currently available. Received: 27 February 1996 / Revised: 4 June 1996     

Plant regeneration from somatic embryos ofTaxus brevifolia

Summary Taxusbrevifolia is the source of paclitaxel (Taxol®), an anticancer drug. A method for regeneration ofTaxus brevifolia from immature zygotic embryos via somatic embryogenesis is described. Embryogenic callus tissues were obtained by culturing immature zygotic embryos on Lloyd and McCown medium (MCM) supplemented with 160 M 2,4-dichlorophenoxyacetic acid (2,4-D) + 5 M benzylaminopurine (BA) + 5 M naphthaleneacetic acid (NAA) for 4 weeks. Putative embryoids were obtained following transfer of cultures to MCM medium supplemented with 4 M BA + 5 M kinetin + 1 M NAA for 6 to 8 weeks. Conversion of embryos was obtained on MCM medium supplemented with 40 M abscisic acid (ABA) + 1% activated charcoal. Development of bipolar structures with recognizable shoot and root apices was observed in somatic embryos. Five percent of somatic embryos were regenerated into plantlets on half-strength growth regulator-free MCM medium.     

“Bacillus thermoantarcticus” sp. nov., from Mount Melbourne,Antarctica: a novel thermophilic species

 A novel thermophilic Gram-positive bacillus, “Bacillus thermoantarcticus”, isolated from geothermal soil near the crater of Mount Melbourne, is described. The organism grows at an optimal temperature of 63^°C at pH 6.0, is oxidase-positive, catalase-negative and produces an exopolysaccharide, an exocellular xylanase, an intracellular alcohol dehydrogenase and exo- and endocellular α-glucosidase(s). The sequence of 16S rDNA is very similar to that of “Bacillus thermoglucosidasius”; however, the guanine-plus-cytosine (G+C) content is 8 mol% higher. The type strain is “Bacillus thermoantarcticus” (DSM 9572). Received : 3 February 1995/Accepted : 12 May 1995     

Biotransformation of monoterpenes and sesquiterpenes by cell suspension cultures of Achillea millefolium L. ssp. millefolium

The transformation capacity of Achillea millefolium L. ssp. millefolium (yarrow) cell suspension cultures was investigated using geraniol (50mg/l) and borneol, menthol, thymol and farnesols (25mg/l) as substrates. Apart from converting these substrates into several biotransformation products, the cell suspension cultures were also able to glycosylate both the substrates and the biotransformation products. aa]Key Words bb]Achillea millefolium L. ssp. millefolium bb]Yarrow bb]Compositae bb]Biotransformation bb]Glycosylation bb]Geraniol bb]Borneol bb]Menthol bb]Thymol bb]Farnesols     

A case-control study on selenium,zinc, and copper in plasma and hair of subjects affected by breast and lung cancer

The purpose of our study was to investigate the relationship between plasma and hair levels of Se, Zn, and Cu, and cancer. We selected a total of 66 patients affected by either breast (38) or lung (28) cancer. They entered into the study at the onset of disease, and before any chemical or radiotherapy. Controls were randomly selected among healthy people and were matched for sex, age, smoking habits, and residence. In the group of breast cancer, a significant decrease in hair Se was found compared to controls (p<0.01), whereas plasma Se was only slightly decreased. No difference between cases and controls was detected in both hair and plasma levels of Zn and Cu. Subjects who developed lung cancer were significantly lower in hair Zn (p<0.05) and Cu (p<0.01) than controls, whereas there was no difference with regard to Se. In addition, plasma Cu of these patients was increased as compared to controls.     

Cytokinins and fruit development in the kiwifruit (Actinidia deliciosa). I. Changes during fruit development

The cytokinin content in fruit tissue of the kiwifruit ( Actinidia deliciosa [A. Chev.] C. F. Liang et A. R. Ferguson var. deliciosa cv. Hayward) was monitored during fruit development to identify which cytokinins were present and if they were linked with specific stages of fruit growth. Cytokinins were isolated and purified by column chromatography and high-performance liquid chromatography and quantified by radioimmunoassay. A novel HPLC step utilising an amine column was successfully introduced as a preparative step in the separation of the O - and 9-glucosides from the free bases and ribosides. The radioimmunoassay results were validated, and the different cytokinins identified, by gas chromatography-mass spectrometry. Cytokinins detected in fruit included the cytokinin free bases, zeatin and isopentenyladenine, their ribosides, nucleotides and both O - and 9-glucosides. Both qualitative and quantitative changes of the cytokinins occurred during fruit development. A decrease in cytokinin concentration occurred after anthesis (from 342 pmol g⁻¹ fresh weight at anthesis to 41 pmol g⁻¹ fresh weight 27 days after anthesis). A large increase in cytokinin concentration and content per fruit occurred as the fruit reached commercial maturity (to 1900 pmol g⁻¹ fresh weight). Individual cytokinins showed quite different patterns. Zeatin, in particular, showed a peak in concentration (13 pmol g⁻¹ fresh weight) 11 days after anthesis that correlated with the beginning of the cell division phase of fruit growth. The accumulation of cytokinin (mostly zeatin riboside or zeatin nucleotide) in mature fruit may be of significance for the postharvest storage of kiwifruit fruit.     

Substrate subsite recognition of the xyloglucan endo-transglycosylase or xyloglucan-specific endo-(1→4)-β-d-glucanase from the cotyledons of germinated nasturtium (Tropaeolum majus L.) seeds

We have investigated the substrate subsite recognition requirement of the xyloglucan endo-transglycosylase/xyloglucan-specific endo-(14)--d-glucanase (NXET) from the cotyledons of nasturtium seedlings. Seed xyloglucans are composed almost entirely of the Glc₄ subunits XXXG, XLXG, XXLG and XLLG, where G represents an unsubstituted glucose residue, X a xylose-substituted glucose residue and L a galactosyl-xylose-substituted glucose residue. Thus in the xyloglucan sequence shown below, the xylose (Xyl) residues at the backbone glucose (Glc) residues numbered — 3,— 2, + 2 and + 3 may be galactose-substituted, and NXET cleaves between the unsubstituted glucose at — 1 and the xylose-substituted glucose at + 1, which never carries a galactosyl substituent. We have isolated the xyloglucan oligosaccharides XXXGXXXG and XLLGXLLG from NXET digests of tamarind seed xyloglucan, have modified them enzymatically using a pure xyloglucan oligosaccharide-specific -xylosidase from nasturtium seeds to give GXXGXXXG and GLLGXLLG, and have identified and compared the products of NXET action on XXXGXXXG, GXXGXXXG, XLLGXLLG and GLLGXLLG. We have also compared the molar proportions of XXXG, XLXG, XXLG and XLLG in native tamarind and nasturtium seed xyloglucans with those in NXET digests of these polysaccharides. Using these and existing data we have demonstrated that NXET action does not require xylosesubstitution at glucose residues — 4, — 2, + 1 and + 3 and that xylose substitution at + 2, is a requirement. There may also be a requirement for xylose substitution at — 3. We have demonstrated also that galactosyl substitution of a xylose residue at + 1 prevents, and at — 2 modifies, chain-cleavage. A partial model for the minimum substrate binding requirement of NXET is proposed.Abbreviations G unsubstituted glucose residue - X xylose-substituted glucose residue - L galactosylxylose-substituted glucose residue - F fucosyl-galactosylxylose-substituted glucose residue - Gal galactose - Glc glucose - HPAE high-performance anion-exchange chromatography - NXET nasturtium xyloglucan endo-transglycosylase or xyloglucan-specific endo-(14)--d-glucanase - Xyl xylose This work was funded jointly by Unilever UK and the Department of Trade and Industry (UK) via the LINK initiative Agro-Food Quality.