Effects of L-Glutamate Transport Inhibition by a Conformationally Restricted Glutamate Analogue (2S,1'S,2'R)-2-(Carboxycyclopropyl)Glycine (L-CCG III) on Metabolism in Brain Tissue In Vitro Analysed by NMR Spectroscopy

(2S,1'S,2'R)-2-(Carboxycyclopropyl)glycine (L-CCG III) was a substrate of Na⁺-dependent glutamate transporters (GluT) in Xenopus laevis oocytes (IC₅₀ 13 and 2 M for, respectively, EAAT 1 and EAAT 2) and caused an apparent inhibition of [³H]L-glutamate uptake in mini-slices of guinea pig cerebral cortex (IC₅₀ 12 M). In slices (350 M) of guinea pig cerebral cortex, 5 M L-CCG III increased both the flux of label through pyruvate carboxylase and the fractional enrichment of glutamate, GABA, glutamine and lactate, but had no effect on total metabolite pool sizes. At 50 M L-CCG III decreased incorporation of ¹³C from [3-¹³C]-pyruvate into glutamate C4, glutamine C4, lactate C3 and alanine C3. The total metabolite pool sizes were also decreased with no change in the fractional enrichment. Furthermore, L-CCG III was accumulated in the tissue, probably via GluT. At lower concentration, L-CCG III would compete with L-glutamate for GluT and the changes probably reflect a compensation for the missing L-glutamate. At 50 M, intracellular L-CCG III could reach > 10 mM and metabolism might be affected directly.     

The beta1 integrin subunit is not a specific component of the costamere domain in human myocardial cells

Studies on altered integrin receptor expression during cardiac hypertrophy and heart failure requires accurate knowledge of the distributional pattern of integrins in myocardial cells. At present the general consensus is that in cardiac muscle the ₁ integrin receptor is mainly localized to the same sarcolemmal domain as vinculin at Z-band levels (costamere). Since most previous studies have been focusing on myocardial integrin distribution in lower mammals, the myocardial localization of the ₁ integrin subunit was investigated in biopsies collected from the auricle of patients undergoing a coronary bypass operation. Non-invasive serial optical sectioning was carried out by immuno-laser scanning confocal microscopy. Double-labelling for vinculin/-actinin, and the cytoplasmic domain for the ₁ integrin subunit, showed that ₁ integrin is deposited throughout both the vinculin/-actinin domains and the non-vinculin/-actinin domains. These results were supported by a semi-quantitative analysis in extended focus images of the latter preparations. Higher magnification views at the electron microscopical levels of the large, extracellular domain of the ₁ integrin subunit disclosed a pronounced labelling in the form of a dense, irregular punctuate pattern that was distributed at Z-disc domains as well as along the entire sarcolemmal area between Z-discs. Our findings show that in human, myocardial cells, the ₁ integrin receptor does not only localize to the surface membrane at the Z-disc level (costamere in cardiac muscle), but has a widespread distribution along the sarcolemma.     

Conformational energy analysis of the leucine repeat regions of C/EBP, GCN4, and the proteins of the myc, jun, and fos oncogenes

It has been recently proposed that certain DNA binding proteins (including C/EBP, GCN4 and themyc, jun, andfos oncogene proteins) share a common structural motif based on helix-promoting regions containing heptad repeat sequences of leucines. It has been suggested that this structure is critical to the biological activity of these proteins, since it facilitates the formation of functional dimers held together by interdigitating leucine side-chains along the hydrophobic interfaces between long -helical regions of the polypeptide chains in a configuration termed the leucine zipper. In this paper, conformational energy analysis is used to determine the preferred three-dimensional structures of the leucine repeat regions of these proteins. The results indicate that, in all cases, the global minimum energy conformation for these regions is an amphipathic -helix with the leucine side-chains arrayed on one side in such a way to favor leucine zipper dimerization. Furthermore, amino acid substitutions in these regions (such as Pro for Leu), that are known to inhibit dimer formation and prevent DNA binding, are found to produce significant conformational changes that disrupt the amphipathic helical structure. Thus, these results provide support for the proposed leucine zipper configuration as a critical structural feature of this class of DNA binding proteins.     

Experimental effects of elevated salinity on three benthic invertebrates in Pyramid Lake,Nevada

Salinity of Pyramid Lake increased from 3.7 to 5.5 between 1933 and 1980. Concern over future reductions in overall species richness prompted experiments to assess responses of dominant lake organisms to elevated salinity. Salinity tolerances of three important benthic invertebrates, Hyalella aztecta, Chironomus utahensis, and Heterocypris sp., were tested in controlled laboratory bioassays and also in a semi-natural environment consisting of large (47 m³) mesocosms.Densities of H. azteca in mesocosms were significantly lower at salinities of 8.0 and 11.0 compared with 5.6 controls in year one, but not in 8.5 salinity mesocosms in year two. The 96-h LC₅₀ for H. azteca was high at 19.5. Short-term mortalities of C. utahensis were 100% at salinities of 13.3 and greater. Fifty-seven percent fewer larvae matured from third to fourth instar at 8.9 than at 5.5 salinity in 17 day subacute bioassays. Furthermore, larval chironomid densities and emergence of adults from mesocosms were significantly reduced at salinities of 8.0 and higher compared with controls. Mortality of Heterocypris sp. was 50% at a salinity of 18.6 in laboratory bioassays and populations in mesocosms ranged between 40 and 100% lower at salinities of 8.0 and 11.0 than in controls.Multiple generation mesocosm experiments indicated all three invertebrates were more sensitive to elevated salinity than results of short-term bioassays. Our studies suggest populations of these invertebrates may be reduced from present levels if Pyramid Lake's salinity were to double, although none are expected to be extirpated. Food habit shifts and reduced production of lake fishes are likely consequences of salinity-induced disruption in the benthic invertebrate forage base.     

Concluding remarks

On the basis of symposium contributions onChlorella, Hibbertia, Eucalyptus, Ambrosia and on numerical approaches some fundamental problems of (bio)systematics, evolution, and taxonomic categories are discussed: Methods available for analysing affinities; conflicting evidence from phenetic, biochemical, cytogenetic and other analyses; further classification problems in cases of intermediacy, etc. While sibs of various levels and their natural hierarchy often can be objectively defined, this appears impossible for particular taxonomic levels itself (e. g. species). A single objective taxonomic system of organisms is unrealistic. Certain guiding lines for relative and practicable concepts of species and genus are proposed.Presented at the symposium Speciation and the Species Concept during the XIIth International Botanical Congress, Leningrad, July 8, 1975.     

Kosten und Nutzen von Zweitbruten bei der Tannenmeise (Parus ater)

Zusammenfassung In einem Aufforstungsgebiet mit Japanlärche und Waldkiefer von 325 ha bei Lingen/Emsland mit 600 künstlichen Nisthöhlen konnten 1974–1993 jährlich 16–98 Brutpaare der Tannenmeise kontrolliert werden; rund zwei Drittel der Paare brüteten im Mittel aller Jahre zweimal pro Saison. Die Reproduktionsrate (Zahl flügger Nestlinge), die lokale Rekrutierungsrate (Zahl der sich fortpflanzenden geburtsortstreuen Jungvögel) und die Überlebensrate einjähriger Tannenmeisen-, die nur einmal brüteten (Gruppe 1), wird verglichen mit einjährigen mit zwei Bruten (Gruppe 2); einjährige mit mißglückter Erst- oder Zweitbrut blieben unberücksichtigt. Als Maß für die Überlebensrate gilt die lokale Wiederfangrate der . Gruppe 2 hatte eine gesichert höhere Reproduktions- und Rekrutierungsrate als Gruppe 1, und zwar nicht nur im 1. Brutjahr, sondern auch über alle Lebenszeit-Brutjahre (lifetime reproduction). Zwischen Brutenzahl und Wiederfangrate der im jeweils nächsten Jahr besteht eine gesichert positive Beziehung. Dies dürfte auf im Duchschnitt bessere Qualität der mit Zweitbruten zurückzuführen sein. Die Ergebnisse stimmen nicht mit der cost of reproduction hypothesis überein.

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Costs and benefits of second broods in Coal Tits (Parus ater)

We compared the reproductive output, local recruitment rates and survival rates of 1 year old Coal Tit females breeding only once (group 1) with the corresponding values of 1 year old females breeding twice (group 2). One year old females which failed first or second broods were excluded. Survival was estimated by the local recovery rate of females during the next breeding season. Our data do not fit with the cost of reproduction hypothesis as females with significantly higher reproductive output and recruitment (group 2) did not show lower survival. We even found a significantly positive correlation between production of a second brood and recovery rate the next year.

     

Zur Biologie,Morphologie und Verhaltensweise von Apion virens Hrbst. (Col., Curculionidae)

Zusammenfassung Die vorliegende Arbeit soll einen Beitrag zur Monographie von Apion virens liefern. Von den einzelnen Stadien werden die Entwicklungsdauer sowie verschiedene morphologische Einzelheiten angegeben. Die Lebensdauer der Imagines beträgt 11–12 Monate, wobei die Käfer allerdings während der Überwinterung Nahrung aufnehmen müssen.Die Ausfärbung der Puppen und Imagines erfolgt progressiv. Der Fortgang dieser Prozesse wird im einzelnen beschrieben.Die Zahl der abgelegten Eier betrug maximal 166/.Untersuchungen zur Phänologie ergaben verschiedene gut abtrennbare Phasen im Laufe des Jahres.Im Wirtspflanzenspektrum der Art spielen Trifolium-Arten die wichtigste Rolle.Die Vorzugstemperatur- und-lichtbereiche zeigen charakteristische Veränderungen ihrer Lage im Laufe des Jahres. Dabei ergeben sich hinsichtlich der Temperatur auch Unterschiede zwischen und .Von den Verhaltensweisen der Imagines werden Kopulation, Eiablage und Putzhandlungen eingehend beschrieben.

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On the biology, morphology and behaviour of apion virens Hrbst. (Col., Curculionidae)

Summary This paper intends to give a contribution to a monography of Apion virens. From the different stages the duration of development and some details of the morphology are presented. The longevity of the adults reaches 11 to 12 months when uptake of food during hibernation is possible.The pigmentation of pupae and adults, which is described in detail, takes place progressively.The maximum number of eggs per female was 166.Investigations about the phenology showed several well separated phases in the course of one year. Trifolium species are the most suitable host plants of A. virens.The range of preference of temperature and humidity changes characteristically during the year. — Between and there exist also differences in the optimum temperature range.Copulation, egg-laying and cleaning behaviour are described in detail.

     

Coccidia of Brazilian edentates: Eimeria cyclopei n.sp. from the silky anteater,Cyclopes didactylus (Linn.) and Eimeria choloepi n.sp. from the two-toed sloth,Choloepus didactylus (Linn.)

Summary Eimeria cyclopei n.sp. is described from the silky anteater, Cyclopes didactylus, from Pará State, north Brazil. Undifferentiated oocysts, passed in the faeces, complete sporulation in seven days at 26 to 28°C. Oocysts are ellipsoidal to sub-spherical, with a mean size of 28.1 × 23.6 m: the wall is 1.5 to 2.0 m thick, apparently with an outer thin, colourless membrane and two inner, thicker, striated and yellowish layers. There is no micropyle, oocyst residuum or polar body. The mean measurements of sporocysts are 19.0 × 9.0 m, and they are slightly asymmetrical, elongate pear-shape, with a plug-shaped Steida body projecting beyond the end of the sporocyst. Sporozoites are as long as or longer than the sporocysts: The sporocyst residuum is scattered between sporozoites in younger specimens and becomes condensed into rounded mass in older ones. The endogenous stages occur in the epithelial cells of the ileum, on the lumenal side of the host-cell nucleus. Uninucleate meront, microgamont and macrogamont precursors are recognizable morphologically. Mature meronts are 20.0 × 15.7 m some produce 12 to 20 merozoites which are 8.7 × 2.0 m, and others 10 to 26 merozoites which are 11.4 × 2.0 to 15.0 × 3.0 m. Mature microgamonts which are 27.5 × 24.1 m, produce from 150 to 170 microgametes of 7.1 × 1.0 m: microgametes have two flagella of unequal length. Mature macrogamonts are 28.4 × 24.5 m Eimeria choloepi n.sp. is recorded from the two-toed sloth, Choloepus didactylus, from the same area of Brazil. Undifferentiated oocysts, passed in the faeces, complete sporulation in 23 days at 26 to 28°C. Oocysts with a mean size of 23.0 × 20.3 m, have a wall 2.0 to 2.5 m thick which is composed of two thick, yellowish and striated outer layers and a delicate, colourless inner one. There is no micropyle, oocyst residuum or polar granule. Mature sporocysts with a mean size of 11.3 × 7.1 m, are ellipsoidal to egg-shaped and have a poorly developed Steida body. The sporocyst residuum is composed of a small number of large globules: The sporozoites are longer than the sporocyst and strongly recurved. The endogenous stages occur in epithelial cells of the ileum, on the lumenal side of the host-cell nucleus. Dimorphic meronts produce 8 to 18 merozoites which are either 13.0 × 2.0 m or 13.0 × 3.0 m. Microgamonts produce 50 to 80 microgametes of 8.0 × 1.0 m. Mature macrogamonts are 18.3 × 17.9 m. ac]19820212     

The Correcting Role of Autonomous 3" →="" 5"="" exonucleases="" contained="" in="" mammalian="" multienzyme="" dna="" polymerase="" complexes"="

A study was made of the correcting role of autonomous 3" 5" exonucleases (AE) contained in multienzyme DNA polymerase complexes of rat hepatocytes or calf thymocytes. DNA was synthesized on phage X174 amber3 or M13mp2 primer–templates, and used to transfect Escherichia coli spheroplasts. Frequencies were estimated for direct and reverse mutations resulting from mistakes made in the course of in vitro DNA synthesis. The error rate of the hepatocyte complex was estimated at 3·10^–6 with equimolar dNTP, and increased tenfold when proteins accounting for 70% of the total 3" 5" exonuclease activity of the complex were removed. The fidelity of DNA synthesis was completely restored in the presence of exogenous AE ( subunit of E. coli DNA polymerase III). Nuclear (Pol _n) and cytosolic (Pol _c) forms of DNA polymerase were isolated from calf thymocytes. The former was shown to contain an AE (TREX2) absent from the latter. As compared with Pol _c, Pol _n had a 20-fold higher exo/pol ratio and allowed 4–5 times higher fidelity of DNA synthesis. The error rate of DNA polymerase complexes changed when dNTP were used in nonequimolar amounts.     

Evaluation of microbial testing methods for the mutagenicity of quinoline and its derivatives

Using the mutational enhancement method and the Ames test, the mutagenicity and potential carcinogenicity of quinoline and its derivatives were determined and compared. Quinoline, 8-hydroxyquinoline, 5-hydroxyquinoline, 8-hydroxyquinoline sulfate, 6-nitroquinoline, 8-nitroquinoline, and 3-methylquinoline were mutagenic in the Ames direct plating test on TA 98 and TA 100 with activating system (S-9) from the rat liver. These compounds were not mutagenic in the mutational enchancement test onEscherichia coli HCR+ strain. 5,7-Dichloro-8-hydroxyquinoline, isoquinoline, and 2-chloroquinoline were nonmutagenic without or with S-9 in both the Ames and mutational enhancement test system. The compounds chloroquine, primaquine diphosphate, quinine hydrobromide, quinine hydrochloride, quinine lactate, quinine urea hydrochloride, quinine ethylcarbonate, quinine dihydrochloride, beta quinine quinine valerate, and quinine glycerophosphate were nonmutagenic with and without S-9 in the Ames test but mutagenic (20–60 g/ml) in the mutational enhancement test method onEscherichia coli HCR+ strains. The observations reported here point out that the Ames test responds negatively to several quinoline derivatives that are positive in the mutational enchancement test method.     

Liver and intestinal fatty acid binding proteins in control and TGFβ1 gene targeted deficient mice

The effect of transforming growth factor beta-1 (TGF1) expression on fatty acid binding proteins was examined in control and two strains of gene targeted TGF1-deficient mice. Homozygous TGF1-deficient 129 × CF-1, expressing multifocal inflammatory syndrome, had 25% less liver fatty acid binding protein (L-FABP) when compared to control mice. The decrease in L-FABP expression was not due to multifocal inflammatory syndrome since homozygous TGF1-deficient/immunodeficient C3H mice on a SLID background had 36% lower liver L-FABP than controls. This effect was developmentally related and specific to liver, but not the proximal intestine, where L-FABP is also expressed. Finally, the proximal intestine also expresses intestinal-FABP (1-FABP) which decreased 3-fold in the TGF1-deficient/immunodeficient C3H mice only. Thus, TGF1 appears to regulate the expression of L-FABP and I-FABP in the liver and the proximal intestine, respectively.Abbreviations L-FABP liver fatty acid binding protein - I-FABP intestinal fatty acid binding protein - TGF1 transforming growth factor beta-1 - TNF- tumor necrosis factor- - MIP- macrophage inflammatory protein- - PMSF phenylmethyl sulfonyl fluoride - PBS phosphate buffered saline     

Continuous culture and synchronization ofHyphomicrobium sp. B-522

A technique was developed for synchronization ofHyphomicrobium sp. strain B-522. Bacteria were grown in continuous culture with methanol (0.1%; v/v) growth limiting. Vitamin B₁₂ (2.5 g/l) was necessary to obtain steady state growth. The critical dilution rate wasD _c =0.112; maximum cell output occurred atD=0.105 (Dx=30 mg l^-1 h^-1). Continuous cultures ofHyphomicrobium B-522 atD=0.110 were used to obtain cells for synchronization experiments. Synchronization was achieved by trapping young hyphal and budding cells in a glass wool column, while the initial swarmer cells were allowed to pass through. By semicontinuously rinsing the system, newly produced swarmers could be sampled in the effluent. The mean length of these synchronous swarmer cells was 1.25 m (s=±0.13 m; range 0,6 m) as compared to 1.40 m (s=±0.21 m; range 1.2 m) for swarmer cells of the continuous culture. Division of synchronous swarmer populations was completed after 7 h; the synchronization index was 0.76.     

Partial mispairing and crossing-over between β0 and δ genes as the origin of the δ β0 thalassemia gene

Summary Two double heterozygous ⁰/⁰ thalassemic sibs of Mexican descent were studied. The father had a ⁰/⁰ genotype, while the mother, one sib and several maternal relatives were ⁰/⁰ heterozygotes. Parental consanguinity and an apparently low frequency of thalassemia among Mexicans suggested a possible common origin of both ⁰ and ⁰ genes. A hypothesis to explain such a possibility is proposed on the basis of a partial mispairing between ⁰ and genes followed by a crossing-over which would results in a ⁰ recombinant gene. This hypothesis could also be extended to explain the 22 gluala, 22 alaglu and 116 arghis Hb variants as recombinants from double crossing-over between and mispaired genes for which the name interstitial-Lepore is proposed.     

Introduction

The only concrete basis for the discontinuous and hierarchical organization of extant organisms lies in their genealogical (i. e. germ line) relationships. Individuals and populations of common descent are called sib or stirps. Ideally, systematic classification is based on the formulas: (1) sib + taxonomic category + name = taxon, and (2) divergent genealogy of sibs + hierarchy of taxonomic categories + names = taxonomic system (Fig. 1).Presented at the symposium Speciation and the Species Concept during the XIIth International Botanical Congress, Leningrad, July 8, 1975.     

The ichneumon wasp Venturia canescens: Oviposition and avoidance of superparasitism

The parthenogenetic ichneumon wasp Venturia (= Nemeritis( canescens (Grav.) carries a single egg in readiness for oviposition in a cavity right at the tip of the long ovipositor. The egg is passed into the cavity during a flexing or cocking movement of the abdomen, and this behaviour can be used to determine whether or not Venturia has deposited an egg into its host. The cocking movement shows that Venturia tends to avoid superparasitism.

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Résumé l'Ichneumonide parthenogénétique Nemeritis canescens porte un seul uf prêt à être pondu dans une cavité fusiforme, juste à la pointe de son long ovipositeur. L'uf est éventuellement émis quand l'ovipositeur pénètre dans une chenille hôte. L'uf chemine le long de l'ovipositeur, et est mis en place dans la cavité apicale pendant un mouvement de flexion très caractéristique de l'abdomen (Cocking Fig. 2) qui est bien distinct du mouvement accompli au moment même de la piqûre de l'hôte (Stabbing Fig. 2).Le mouvement dit d'armement (Cocking) est toujours effectué juste après la ponte dans un hôte sain, assurant ainsi la mise en place d'un nouvel uf pour une autre piqûre. L'absence du mouvement de Cocking entre deux actes de piqûre dans deux hôtes successifs indique que la piqûre dans le premier hôte n'a pas été suivie de ponte.En utilisant le mouvement de Cocking comme indicateur de ponte on peut démontrer que Nemeritis reconnaît la présence d'un uf dans une hôte cinq minutes après que celui-ci a été parasité, et évite le superparasitisme en effectuant une piqûre non suivie de ponte. La proportion de piqûres stériles s'accroît quand l'hôte héberge un uf dont le développement est plus avancé, l'évitement du superparasitisme atteint sa plus forte proportion 30 minutes seulement après le dépôt du premier uf (Fig. 3).

     

Partial purification and characterization of a folatebinding protein from human choroid plexus

A folate-binding protein (binder) from human choroid plexus was solubilized with Triton X-100 and partially purified in three steps: (1) affinity chromatography, (2) Sephadex G-200 column chromatography, and (3) polyacrylamide gel electrophoresis. When the partially purified binder was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the binding activity was located in the region of the gel with a molecular weight between 45,000 and 60,000. The specific activity of the binder after the three purification steps was 1.2 g folic acid/mg protein, a 316-fold purification. Binding activity of the partially purified binder decreased below pH 6.0 and above pH 8.0 was unaffected by treatment with ribonuclease or deoxyribonuclease, but was abolished with trypsin, chymotrypsin, or protease (Streptomyces griesus). The binding of folic acid to the human binder was inhibited by folate > H₄-folate > methyl-H₄-folate dihydrofolate pteroic acid methotrexate aminopterin.     

Transient gene expression in electroporated Picea glauca protoplasts

The reporter gene for chloramphenicol acetyltransferase (CAT) was introduced into white spruce (Picea glauca (Moench) Voss.) protoplasts by electroporation. CAT transient gene expression was increased by increasing the concentration of pCaMVCN plasmid and was affected by the level of the applied voltage. Highest CAT activities were obtained after electroporation with a pulse of 350V.cm^–1 having an exponential decay constant of approximately 105ms. Linearized plasmid constructs gave much higher levels of CAT activity than circular plasmid. Attempts to use the Escherichia coli -glucuronidase gene (-GUS) as a marker gene revealed very high levels of -GUS-like activity in electroporated protoplasts. This activity was mainly due to a small molecule and may mask successful transformation since -GUS-like activity increased when plasmid DNA was present during electroporation.Abbreviations CAT chloramphenicol acetyltransferase - -GUS -glucuronidase - MUG 4-methyl umbelliferyl glucuronide - F microfarads NRCC No. 29150     

Killing ofLegionella pneumophila by human serum and iron-binding agents

The inhibitory effect of serum on the growth and survival ofLegionella pneumophila Bloomington 2 was investigated. When incubated in the presence of 20%–50% normal human serum for 10 h, viability was decreased by >99%. Heat-inactivated or <40% normal serum supplemented with 50 M iron was not inhibitory. The addition of guinea pig complement to heat-inactivated serum resulted in killing of approximately 98% of the cells. Growth in buffered yeast extract broth was inhibited by the addition of ferric iron-binding compounds. Minimum bactericidal concentrations at 37°C were 10 M apotransferrin, 35 M 1,10-phenanthroline, and 50 M deferoxamine. Addition of iron chelators to normal serum did not accelerate killing. Egg yolk-passaged virulent strains and agar-grown avirulent strains exhibited similar serum sensitivity. Results of this study indicate that complement and serum transferrin are antagonistic to the growth ofLegionella in serum.     

Preliminary Study of Vertebral Growth Rings in the Whale Shark, Rhincodon typus, from the East Coast of South Africa

Growth rings (GR) in vertebral centra of 15 whale sharks, Rhincodon typus, four female (418–750cm precaudal length), 10 male (422–770cm), and one of unknown sex (688cm), were examined using x-radiography. GR counts were made from scanned images and count precision was determined using the average percentage error index (4.19%) and the index of precision D (3.31%). In females, counts ranged from 19 GR (418cm) to 27 GR (750cm); in males from 20 GR (670cm) to 31 GR (770cm). Three mature males had 20 GR (670cm), 24 GR (744cm) and 27 GR (755cm). A female with 22 GR (445cm) was adolescent. There was a linear relationship between centrum dorsal diameter and body length, and back-calculated body lengths at number of GR are presented. A linear relationship between body length and number of GR prevented the calculation of von Bertalanffy parameters from either observed or back-calculated values.     

Root exudation and physiological status of a root-colonizing fluorescent pseudomonad in mycorrhizal and non-mycorrhizal pepper (Capsicum annuum L.)

Ultramafic (serpentine) soils from and adjacent to the Dun Mountain Ophiolitic Belt, South Island, New Zealand were analysed for 11 elements in order to establish to what degree edaphic factors influenced the character of the overlying vegetation. Using principal components analysis with a mutual plot of the first two principal components, involving the total elemental concentrations in the soils, it was possible to divide the soils into 6 virtually non-overlapping fields, each of which represented a specific vegetation community. Component 1 was essentially an ultramafic plot with heavy loadings from the elements chromium, cobalt, iron, magnesium, manganese, and nickel. Component 2 was a non ultramafic plot with heavy loadings from aluminium, copper and zinc. For elements extracted from the soils at pH 5.9, discrimination was somewhat poorer but confirmed the great importance of magnesium and nickel as controlling elements for the serpentine vegetation. It was concluded that the results indicated the overriding importance of edaphic factors in controlling the serpentine vegetation.