Viability and virulence of blastospores of Metarhizium anisopliae (Metch.) Sorokin after storage in various liquids at different temperatures

Blastospores of three strains of Metarhizium anisopliae were stored in 18 liquids at 4°C, 20°C and 35°C for 18 weeks, 12 weeks or 9 days respectively. Viability was quantified by determination of their germination. In bioassays the virulence of stored blastospores was studied using adults and third instars of Locusta migratoria migratorioides (R. & F.) and compared to those of freshly produced blastospores and conidia. Generally, there was great variability in the viability of blastospores, depending on the fungal strain and the liquids used. Blastospores survived best at 4°C in 10% hydroxyethyl starch; for example, germination of M. anisopliae strain 97 still amounted to more than 80% after storage for 18 weeks. Other suitable liquids were deionized water, 25% Ringer's solution and 1% sodium alginate. The viability of blastospores stored at 20°C was considerably shorter than at 4°C. During storage for 12 weeks at 20°C the best protective liquids for M. anisopliae strain 97 were 25% Ringer's solution (43% germination), deionized water (23%) and 10% hydroxyethyl starch (23%). At 35°C, 45% of M. anisopliae strain 97 blastospores still germinated after storage for 7 days in 25% glycerol. The bioassays revealed that the virulence of blastospores after storage was comparable to that of fresh ones and even better than that of fresh conidia. In general, the LT₅₀ was about 4–6 days at an alternating day/night temperature of 28/20°C.     

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.     

Influence of phytogenic surfactants (quillaya saponin and soya lecithin) on bio-elimination of phenanthrene and fluoranthene by three bacteria

The influence of two phytogenic surfactants on the elimination of polycyclic aromatic hydrocarbons (PAH) was studied in shaken-batch cultures of three soil bacteria under axenic conditions. At sufficiently high concentrations, quillaya saponin and soybean lecithin solubilized phenanthrene or fluoranthene efficiently. However, complete solubilization of the PAH by lecithin only doubled the maximal rate of elimination of the two PAH compounds by Pseudomonas 0259, strain MKm (Rhizomonas ?) and Mycobacterium EMI 2. By contrast, quillaya saponin did not improve PAH bioavailability, and in strain MKm it caused significant growth lags above 2.5 g/l. Simultaneously with the elimination of the PAH the bacteria utilized the surfactants as substrates for growth. Intermediate formation of PAH metabolites was noted. The results suggest that some phytogenic surfactants might improve PAH bioavailability in rhizospheres.     

Differences in the location of subcotyledonary buds among Epilobium angustifolium L., E. dodonaei Vill. and E. fleischeri Hochst. (Onagraceae) and effects on architecture and population structure

STÖCKLIN, J., 1992. Differences in the location of subcotyledonary buds among Epilobium angustifolium L., E. dodonaei Vill. and E. fleischeri Hochst. (Onagraceae) and effects on architecture and population structure . Morphological and architectural features in the two closely related pioneer plant species Epilobium dodonaei and E. fleischeri are examined in cultivation and in the field and compared with E. angustifolium. In E. angustifolium , the aerial shoot system is renewed every year from buds on horizontal roots and results in a horizontal spread and a clonal growth form. In E. dodonaei , bud formation is restricted to the hypocotyl and in larger plants to the transitional region between root and shoot. Consequently this species shows no vegetative mobility and develops a shrub-like habit. The alpine E. fleischeri combines the habit of E. angustifolium and E. dodonaei and may either develop successive generations of shoots from the transitional region between root and shoot and/or exploit new areas by horizontal roots and the formation of shoots from root buds. The simple difference in the location of renewal buds is accentuated by cumulative growth. The study shows that E. dodonaei and E. fleischeri , which often are considered as subspecies, are separated by fundamental differences in their architectural models. The ecological and demographic implications of these differences are discussed.     

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.

     

Genetic Analysis in Wood-Decaying Fungi I. Genetic Variation and Evidence for Allopatric Speciation in Pleurotus ostreatus using Phenoloxidase Zymograms and Morphological Criteria

Using electropherograms (zymograms) of the phenoloxidase laccase and characteristics of mycelial growth and fruit body production, a distinct morphological and biochemical differentiation of two geographically isolated (allopatric) populations of the wood-rotting basidiomycete Pleurotus ostreatus became evident. No limitation in their outbreeding ability was observed, however. A specific secretory mechanism for an extracellular laccase, genetically different in the two geographical races, could be detected. An approximately 1: 1 segregation of this laccase band in the F₁ generation indicates that specific secretion of this enzyme is controlled by one gene only, Different degrees of genetic variation as shown by differences in the respective laccase spectra were found in the two geographical races. Only one enzyme band out of nine multiple laccases was found to be specific for fruit bodies. The value of zymograms for chemotaxonomic purposes, for the understanding of microevolution and for determination of genetic variation in fungi is critically discussed.     

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.     

Seed production and seed quality in a calcareous grassland in elevated CO2

In diverse plant communities the relative contribution of species to community biomass may change considerably in response to elevated CO₂. Along with species‐specific biomass responses, reproduction is likely to change as well with increasing CO₂ and might further accelerate shifts in species composition. Here, we ask if, after 5 years of CO₂ exposure, seed production and seed quality in natural nutrient‐poor calcareous grassland are affected by elevated CO₂ (650 μ L L^?1 vs 360 μ L L^?1) and how this might affect long‐term community dynamics. The effect of elevated CO₂ on the number of flowering shoots (+ 24%, P < 0.01) and seeds (+ 29%, P = 0.06) at the community level was similar to above ground biomass responses in this year, suggesting that the overall allocation to sexual reproduction remained unchanged. Compared among functional groups of species we found a 42% increase in seed number (P < 0.01) of graminoids, a 33% increase (P = 0.07) in forbs, and no significant change in legumes (? 38%, n.s.) under elevated CO₂. Large responses particularly of two graminoid species and smaller responses of many forb species summed up to the significant or marginally significant increase in seed number of graminoids and forbs, respectively. In several species the increase in seed number resulted both from an increase in flowering shoots and an increase in inflorescence size. In most species, seeds tended to be heavier (+ 12%, P < 0.01), and N‐concentration of seeds was significantly reduced in eight out of 13 species. The fraction of germinating seeds did not differ between seeds produced in ambient and elevated CO₂, but time to germination was significantly shortened in two species and prolonged in one species when seeds had been produced in elevated CO₂. Results suggest that species specific increases in seed number and changes in seed quality will exert substantial cumulative effects on community composition in the long run.