Über eine besondere Form vonAsterococcus superbus und deren systematische Stellung

Zusammenfassung Die Morphologie und Fortpflanzung einer besonderen Form vonAsterococcus superbus werden beschrieben. Diese Form wird jedoch vorläufig, weil der Typus in Details nicht völlig geklärt ist, kein taxonomischer Rang zugesprochen. Es wird auch über die Abgrenzung der GattungAsterococcus gegenüber ähnlichen und verwandten Gattungen berichtet. Die Gattung wird neu charakterisiert und begrenzt. Dabei werden die geschichtete Gallerthülle und dieChlamydomonas-ähnlichen Zellen hervorgehoben, wogegen das sternförmige Chromatophor allein nicht als maßgebendes Gattungsmerkmal anerkannt wird. Weil auch die frühere FamiliePalmellaceae den heutigen systematischen Ansprüchen nicht mehr entspricht, wird diese neu bewertet. Die FamiliePalmellaceae gehört mit der GattungPalmella zu denChlorococcales. Deswegen wird für den Rest der ursprünglichen Familie eine neue Benennung,Gloeococcaceae, vorgeschlagen.     

Vergleichende Untersuchungen der Feinstruktur einiger Chlamydomonas-Arten

Zusammenfassung VierChlamydomonas-Arten, die in Reinkulturen gezüchtet wurden —Ch. noctigama var.ellipsoidea, Ch. transita,Ch. terricola fo. undCh. baca — werden vergleichenden Untersuchungen des Zellbaues mit dem Lichtund Elektronenmikroskop unterworfen. Es sollte festgestellt werden, inwieweit das Elektronenmikroskop die Taxonomie dieser Gattung beeinflussen oder erweitern kann und ob Untersuchungen mit dem Lichtmikroskop ausreichen. Alle taxonomisch wichtigen Merkmale der vegetativen Zelle wurden untersucht und verglichen — Membran, Papille, Geißelinsertion, Chloroplast, Augenfleck, Pyrenoid, Zellkern und pulsierende Vakuolen. So lassen sich auch andere Einzelheiten, die für den Zellbau im allgemeinen wichtig sind, beobachten, im ganzen wird aber festgestellt, daß vorläufig die Untersuchungen mit dem Lichtmikroskop maßgebend bleiben, soweit sie die Taxonomie der GattungChlamydomonas betreffen, und daß sie zur Unterscheidung einzelner Taxa ausreichen. Das Elektronenmikroskop kann dort, wo gewisse Details vor allem bei sehr kleinzelligen Arten, mit dem Lichtmikroskop nicht völlig klar erscheinen, zur Ergänzung dienen.     

ÜberHydrianum viride (Characiaceae,Chlorophyceae), seine fortpflanzung und taxonomie

The little known epiphytic algaHydrianum viride was studied and pictured. The morphology and the variability of the vegetative cells are described in detail and compared with the observations of other authors. For the first time typical biflagellate zoospores of the chlorophycean-type have been recognized and the course of the asexual reproduction is studied. The residual protoplasm, that is the proximal half of the zoosporangium protoplast, growth up to the original size, typical for the genusHydrianum. The life cycle, especially the settling down of the zoospores, is described.Hydrianum viride belongs to the characteristic inhabitants of peaty waters; it belongs together with the host alga,Microspora loefgrenii, to the dominants of algal association of peat-springs. At last the taxonomic position and the synonyma of this organism are discussed.

     

Über einen intrazellulären Parasiten beiCryptomonas (Cryptophyceae), I

An intracellular parasite occurring inCryptomonas rostratiformis and less numerously also inC. erosa andC. phaseolus. The parasite is described. It grows in the dorsal side of the host near the nucleus from which it is optically indistinguishable in young stages. When mature the parasite fills 1/3 to 1/2 the volume of theCryptomonas cell. It is seen as a colourless blister, which pushes back the plastid of the host. Reproduction occurs by separation of the protoplast into a hundred or moreBodo-like swarmers which perhaps represent the infectious phase. Under certain conditions, however, such as during decline of theCryptomonas population, the parasite transforms into thick-walled spindle-shaped cysts. Like the swarmers these cysts are released by rupture of the cryptomonad cells. The fate of the cysts is not known. TheCryptomonas population is destroyed by the infection in the course of a few days. Literature studies have shown that the parasite has been known for a long time, but considered incorrectly by different authors as part of theCryptomonas, or as a result of phagotrophic uptake of theCryptomonas. The parasite is compared with a somewhat similar parasite inMallomonas, and with certain parasitic dinoflagellates. The similarity with the latter is superficial only as it posesses a eucaryotic nucleus. The parasite shows some similarity with the genusParadinium (Mycetozoa) as well as with certainSporozoa.

     

L<Subscript>2</Subscript>-norm multiple kernel learning and its application to biomedical data fusion

Background  

This paper introduces the notion of optimizing different norms in the dual problem of support vector machines with multiple kernels. The selection of norms yields different extensions of multiple kernel learning (MKL) such as L _∞, L ₁, and L ₂ MKL. In particular, L ₂ MKL is a novel method that leads to non-sparse optimal kernel coefficients, which is different from the sparse kernel coefficients optimized by the existing L _∞ MKL method. In real biomedical applications, L ₂ MKL may have more advantages over sparse integration method for thoroughly combining complementary information in heterogeneous data sources.     

Comparative analysis of DNA polymorphisms and phylogenetic relationships among Syzygium cumini Skeels based on phenotypic characters and RAPD technique

The Indian black berry (Syzygium cumini Skeels) has a great nutraceutical and medicinal properties. As in other fruit crops, the fruit characteristics are important attributes for differentiation were also determined for different accessions of S. cumini. The fruit weight, length, breadth, length: breadth ratio, pulp weight, pulp content, seed weight and pulp: seed ratio significantly varied in different accessions. Molecular characterization was carried out using PCR based RAPD technique. Out of 80 RAPD primers, only 18 primers produced stable polymorphisms that were used to examine the phylogenetic relationship. A sum of 207 loci were generated out of which 201 loci found polymorphic. The average genetic dissimilarity was 97 per cent among jamun accessions. The phylogenetic relationship was also determined by principal coordinates analysis (PCoA) that explained 46.95 per cent cumulative variance. The two-dimensional PCoA analysis showed grouping of the different accessions that were plotted into four sub-plots, representing clustering of accessions. The UPGMA (r = 0.967) and NJ (r = 0.987) dendrogram constructed based on the dissimilarity matrix revealed a good degree of fit with the cophenetic correlation value. The dendrogram grouped the accessions into three main clusters according to their eco-geographical regions which given useful insight into their phylogenetic relationships.     

不同耕作措施对冬小麦-夏玉米复种连作系统土壤有机碳和水分利用效率的影响

在连续8年田间定位试验的基础上,分析了关中平原冬小麦 夏玉米复种连作系统2008—2009年连续两个生长季期间不同耕作措施(结合秸秆还田和不还田)对土壤有机碳和水分利用率的影响.结果表明: 相对于传统耕作,保护性耕作有利于土壤有机碳、水分利用效率和作物产量的提高,其中在“深松+秸秆还田”耕作模式下的增幅最高,土壤有机碳含量在0～30 cm土层增幅达到19.5%,水分利用效率和作物产量提高了16.9%和20.5%,而免耕模式则有效提高了0～10 cm土层有机碳含量.在该地区土壤和气候条件下,深松结合秸秆粉碎还田是最理想的耕作模式,最有利于土壤有机碳累积,并提高水分利用效率和作物产量.