Predicting invertebrate diversity from disturbance regimes in forest streams

The link between substrate disturbance and stream invertebrate species richness is often complicated by the fact that substrate disturbance removes both invertebrates and periphyton (a potential food source). It is never clear whether disturbance acts directly on species diversity by removing animals or indirectly by reducing one of their food sources. To examine this relationship invertebrate diversity patterns were examined in 25 forest streams in Urewera National Park, New Zealand, where light attenuation from the forest canopy was postulated to limit periphyton biomass and remove the confounding influence of periphyton on the link between substrate disturbance and invertebrate diversity. Invertebrate species richness declined linearly with increasing substrate disturbance. Although periphyton biomass was comparatively low, species richness was more strongly related to periphyton biomass than to any disturbance measure. The highly mobile nature and terrestrial reproductive stage of many lotic invertebrates suggest that colonisation dynamics may have a more important influence on diversity patterns than monopolisation of resources for population growth. Although both the intermediate disturbance hypothesis and the dynamic equilibrium model encompass colonisation as a critical determinant of diversity both models also require a trade-off between the colonising and competitive ability of individual species; a phenomenon which does not appear to occur widely in lotic communities. Rather, it is postulated that resource levels will set an upper limit to the species richness of a benthic community that can be achieved through colonisation of taxa in the absence of disturbance, while disturbance removes taxa and resets the colonisation process.     

Late Cretaceous follicular fruits from southern Sweden with systematic affinities to early diverging eudicots

Eight new species in seven new genera of follicular fruits are described from the Late Cretaceous of southern Sweden. They are Agapitocarpus emisxus , Chontrocarpus pachytoichus , Maiandrocarpus moirasmenus , Malliocarpus batrachoides , Mitocarpus elegans , Xylocarpus rhitidoides , Zeugarocarpus adroagathus and Z. leptoagathus . The fossil follicles are borne along infructescence axes or more commonly occur as isolated, dispersed fruits. Three genera, Maiandrocarpus , Mitocarpus and Zeugarocarpus , have follicles in distinct pairs borne spirally on an infructescence axis. Each follicle of a pair faces the axis with its ventral slit, which strongly indicates that the paired follicles were derived from two separate, monocarpellate flowers rather than from a single, bicarpellate flower. One genus ( Malliocarpus ) has follicles borne individually in the infructescence and three others ( Agapitocarpus , Chontrocarpus and Xylocarpus ) are known only as dispersed follicles. The paired follicles share many features with most of the dispersed follicles, including a sessile stigmatic area, a three-layered simple follicle wall, a simple vascular system composed of one dorsal and two lateral bundles, as well as a marginal-linear placentation bearing several anatropous ovules. Accordingly they are thought to belong to the same complex of taxa. The general structure of the fossils and comparison with modern angiosperms suggest that the fossils might represent an extinct lineage within or close to basal eudicots and many characters are shared with members of extant Proteaceae.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 377–407.     

THE MIDDLE ORDOVICIAN PROVENTOCITUM PROCERULUM RADIOLARIAN ASSEMBLAGE OF SPITSBERGEN AND ITS BIOSTRATIGRAPHIC CORRELATION

Abstract: The Proventocitum procerulum radiolarian assemblage from the Valhallfonna Formation of Spitsbergen is described for the first time in some detail from material investigated in transmitted light. A number of species are recognized in the well‐preserved material, showing unexpected diversity. The age of the fauna is restricted to the early Darriwilian (Da1‐2), based on comparison with precisely dated radiolarian assemblages from the Cow Head and Table Head Groups of western Newfoundland. Most species, however, are left in open nomenclature until additional material is available for SEM investigation. Inanigutta magnifica n. sp. is described as new.     

Valproate is an anti-androgen and anti-progestin

Anti-convulsant treatment is associated with a high prevalence of reproductive dysfunction compared with age-matched non-epileptics. We examined the widely used anti-convulsants valproate (VPA) and carbamazepine (CBZ) for steroidal bioactivity using a yeast-based steroid receptor-beta-galactosidase reporter assay for the androgen receptor (AR), progesterone receptor (PR) or estrogen receptor (ER). Bioassays were performed (a) to detect agonist activity by exposing yeast to 100 microM CBZ or VPA or (b) to detect antagonist activity by exposing yeast stimulated with testosterone (5 x 10(-9) M, AR), progesterone (1.6 x 10(-9) M, PR) or estradiol (2.6 x 10(-11) M, ER) together with either VPA or CBZ for 4 (PR) or 16 (AR, ER) hours. VPA showed dose-dependent (1-800 microM) inhibition of progesterone-induced PR- and testosterone-induced AR activity but had no ER antagonist bioactivity and no significant PR, AR or ER agonist bioactivity. VPA also showed a dose-dependent (1-200 microM) blockade of DHT's suppression of AR-mediated NF-kappaB activation in human mammalian cells. By contrast, CBZ had no significant PR, AR or ER agonist or AR and ER antagonist bioactivity but at the highest concentration tested (800 microM) it did antagonize PR activity. We conclude that VPA is a non-steroidal antagonist for human AR and PR but not ER. VPA's androgen and progesterone antagonism at concentrations within therapeutic blood levels (350-700 microM) seems likely to contribute to the frequency of reproductive endocrine disturbances among patients treated with VPA.     

The performance of fungal xylan-degrading enzyme preparations in elemental chlorine-free bleaching for Eucalyptus pulp

Cellulase-free xylan-degrading enzyme preparations from Acrophialophora nainiana, Humicola grisea var. thermoidea and two Trichoderma harzianum strains were used as bleaching agents for Eucalyptus kraft pulp, prior to a chlorine dioxide and alkaline bleaching sequence. In comparison to the control sequence (performed without xylanase pretreatment), the sequence incorporating enzyme treatment was more effective. Removal of residual lignin was indicated by a reduction in kappa number. Overall, enzyme preparations from T. harzianum were marginally more effective in reducing pulp viscosity and chlorine chemical consumption and improving the brightness of the kraft pulp. However, the highest reduction in pulp viscosity was mediated by the xylanase preparation from A. nainiana. Xylanase pretreatment compares very favorably with that of chemical pulping. Journal of Industrial Microbiology & Biotechnology (2002) 28, 204–206 DOI: 10.1038/sj/jim/7000227 Received 27 April 2001/ Accepted in revised form 03 November 2001     

A NEW BASAL PTEROSAUR GENUS FROM THE UPPER TRIASSIC OF THE NORTHERN CALCAREOUS ALPS OF SWITZERLAND

Abstract:  A lower jaw with multicusped teeth and a number of unique characteristics was discovered in an extensive exposure of the Upper Triassic Kössen Formation in the Northern Calcareous Alps. The ramus of the jaw is high and dominated by a row of large, oval foramina that lies parallel to the tooth row. In addition, the anterior portion of the dentary exhibits a large number of nutritive foramina and small pits, which might indicate an association with a soft tissue structure and/or the presence of a keratinous cover of that area during life. All elements of the jaw are thin-walled and hollow, possibly pneumatic. Two teeth are preserved within the dentary. One is tricuspid and the other bears four cuSPS. The teeth are noticeably small in comparison with the overall size of the ramus, being only one-third of the height of the ramus. The teeth show a strong similarity to those of the well-known basal pterosaur genus Eudimorphodon , whose jaw morphology, however, clearly differs from the specimen described in this study. The dentition and the pneumatic bone structure make an assignment to the Pterosauria plausible. Based on the great number of distinct morphological characters the specimen is described as Caviramus schesaplanensis gen. et sp. nov.     

HUMAN B CELL DIFFERENTIATION: DEPENDENCE ON INTERACTIONS WITH MONOCYTES AND T LYMPHOCYTES VIA CD40, CD80 (B7.1), AND THE CD2-LIGANDS CD48 AND CD58 (LFA-3)

B cell differentiation depends on cellular interactions with T lymphocytes and monocytes via adhesion molecules (AM). In order to characterize AM which are required for B cell differentiation immunoglobulin production using unseparated peripheral blood mononuclear cells (PBMC) was studied. Unstimulated human PBMC were cultured for 9 days with mAb directed at CD2/CD48, /CD58, CD59, CD5/CD72, CD11a—CD18/CD54, CD28/CD80, CD86, CD40/CD40L, or rat CD2 (control). B cell differentiation was quantified measuring IgM and in some cases IgA, IgG, and IgE production. IgM levels were significantly reduced by mAb against CD40, CD48, CD58 and CD80. The reduction was not due to isotype switching to IgA, IgG or IgE. The role of CD40, CD48, CD58 and CD80 was further investigated after depletion of different cell types. Depletion of monocytes and NK cells resulted in no detectable IgM production irrespective of added mAbs. In contrast, IgM production was still present after depletion of T cells and NK cells. Only mAb against CD80 and CD48 significantly reduced IgM production, the reduction of IgM production by anti-CD40 mAb was less than in the presence of T cells. Importantly, anti-CD58 mAb had no effect on IgM production after T cell and NK cell depletion. Taken together, the AM CD40, CD48, CD58, and CD80 are involved in Ig production of unseparated PBMCs. In this model of B cell differentiation only the AM CD58 depend on the presence of T cells while CD48 and CD80 help was found to be T cell independent.     

Cold hardiness of some Alpine Collembola

Abstract.

• 1 Individual supercooling points ranged from -2 to -44°C for six species of springtails, five species from the Swiss Alps and one from lowland Britain. Individuals of Isotomurus alticola (Carl) and Isotoma viridis Bourlet without gut contents had substantially lower supercooling points than those containing food material.
• 2 Juveniles were more cold resistant than adults in both I.alticola and Isotoma hiemalis Schött, both with respect to supercooling point and to their survival at prolonged subzero temperatures.
• 3 Temperature and acclimation time affected the degree of supercooling of four of the Alpine species especially I.hiemalis.
• 4 Duration of culture period had no consistent influence on the supercooling potential of all the species.
• 5 Tests for glycerol in the body fluids of the five Alpine springtails were negative, but the presence of a sugar, probably glucose, together with a five carbon polyhydric alcohol was indicated by chromatography.