Beitrag zur Kenntnis der chemischen Zusammensetzung derPhragmiti-Magnocaricetea und derAgropyro-Rumicion-Arten

Zwanzig Pflanzen der KlassePhragmiti-Magnocaricetea (Kennarten der einzelnen pflanzen-soziologischen Einheiten) und des VerbandesAgropyro-Rumicion crispi wurden den chemischen Analysen unterzogen. Die Pflanzenproben wurden auf den Wiesen der Trockengebiete S-Mährens und der SW-Slowakei gesammelt, u. zw. aus den pflanzensoziologisch, definierbaren Einheiten (Assoziationen der VerbändePhragmition, Caricion gracilis, Caricion rostratae undAgropyro-Rumicion). Die Resultate wurden mit der chemischen Zusammensetzung der in anderen Gebieten vorkommenden Pflanzen verglichen. Es zeigten sich Zusammenhänge zwischen der genetisch bedingten chemischen Zusammensetzung bestimmter Artengruppen und den Eigenschaften des Substrats. In diesem Sinne gibt es allgemeine Unterschiede zwischen den VerbändenCaricion gracilis undCaricion rostratae. Die Arten desAgropyro-Rumicion zeigen im Durchschnitt engere Bindung an die Gesellschaften desCnidion-Verbandes als an dasCaricion gracilis.     

Assessing adhesion forces of type I and type IV pili of Xylella fastidiosa bacteria by use of a microfluidic flow chamber

Xylella fastidiosa, a bacterium responsible for Pierce's disease in grapevines, possesses both type I and type IV pili at the same cell pole. Type IV pili facilitate twitching motility, and type I pili are involved in biofilm development. The adhesiveness of the bacteria and the roles of the two pili types in attachment to a glass substratum were evaluated using a microfluidic flow chamber in conjunction with pilus-defective mutants. The average adhesion force necessary to detach wild-type X. fastidiosa cells was 147 +/- 11 pN. Mutant cells possessing only type I pili required a force of 204 +/- 22 pN for removal, whereas cells possessing only type IV pili required 119 +/- 8 pN to dislodge these cells. The experimental results demonstrate that microfluidic flow chambers are useful and convenient tools for assessing the drag forces necessary for detaching bacterial cells and that with specific pilus mutants, the role of the pilus type can be further assessed.     

Contribution to the knowledge of the savanna and forb-rich communities of Pinar del Rio Province (Cuba)

Phytosociological analysis of savanna and forb-rich communities in the Pinar del Rio Province was done in the area of Remates de Guane; one locality lies on the seashore in the western part of the province. Altogether six associations were distinguished. Five of them, viz.Sclerio curtissii-Centelletum erectae, Schultezio guianensis-Rhynchosporetum fascicularis, Cassio diphyllae-Hypericetum stypheloidis, Polygalo squamifoliae-Dichromenetum seslerioidis andPhyllantho juncei-Aristidetum, all newly described in this paper, are classified into the order ofAcoelorapho-Colpothrinacetalia Bal.-Tul. inBal.-Tul. etCapote 1985 with two alliances. One association, thePaspalo debilis-Asteretum grisebachii Bal.-Tul. etCapote 1992, was put into the order ofAsteretalia grisebachii Bal.-Tul. inBal.-Tul. etCapote 1992 with one alliance bound to inland moving dunes. The plant composition reflects soil quality, above all the water regime. Very interesting is the presence of theByrsonimo crassifoliae-Andropogonetalia teneris-species in the association ofPolygalo-Dichromeneteum seslerioidis indicating the rich presence of stones in the upper part of the soil profile.     

Impact of bone marrow-derived mesenchymal stromal cells on experimental xenogeneic graft-versus-host disease

Background aimsGraft-versus-host disease (GVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation caused by donor T cells reacting against host tissues. Previous studies have suggested that mesenchymal stromal cells (MSCs) could exert potent immunosuppressive effects.MethodsThe ability of human bone marrow derived MSCs to prevent xenogeneic GVHD in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice and in NOD/SCID/interleukin-2Rγ(null) (NSG) mice transplanted with human peripheral blood mononuclear cells (PBMCs) was assessed.ResultsInjection of 200 × 10⁶ human PBMCs intraperitoneally (IP) into sub-lethally (3.0 Gy) irradiated NOD/SCID mice also given anti-asialo GM₁ antibodies IP 1 day prior and 8 days after transplantation induced lethal xenogeneic GVHD in all tested mice. Co-injection of 2 × 10⁶ MSCs IP on day 0 did not prevent lethal xenogeneic GVHD induced by injection of human PBMCs. Similarly, injection of 30 × 10⁶ human PBMCs IP into sub-lethally (2.5 Gy) irradiated NSG mice induced a lethal xenogeneic GVHD in all tested mice. Injection of 3 × 10⁶ MSCs IP on days 0, 7, 14 and 21 did not prevent lethal xenogeneic GVHD induced by injection of human PBMCs.ConclusionsInjection of MSCs did not prevent xenogeneic GVHD in these two humanized mice models.     

Increased Dendritic Spine Density and Tau Expression Are Associated with Individual Differences in Steroidal Regulation of Male Sexual Behavior

Male sexual behavior (MSB) is modulated by gonadal steroids, yet this relationship is highly variable across species and between individuals. A significant percentage (∼30%) of B6D2F1 hybrid male mice demonstrate MSB after long-term orchidectomy (herein after referred to as “maters”), providing an opportunity to examine the mechanisms that underlie individual differences in steroidal regulation of MSB. Use of gene expression arrays comparing maters and non-maters has provided a first pass look at the genetic underpinnings of steroid-independent MSB. Surprisingly, of the ∼500 genes in the medial preoptic area (MPOA) that differed between maters and non-maters, no steroid hormone or receptor genes were differentially expressed between the two groups. Interestingly, best known for their association with Alzheimer’s disease, amyloid precursor protein (APP) and the microtubule-associated protein tau (MAPT) were elevated in maters. Increased levels of their protein products (APP and tau) in their non-pathological states have been implicated in cell survival, neuroprotection, and supporting synaptic integrity. Here we tested transgenic mice that overexpress tau and found facilitated mounting and intromission behavior after long-term orchidectomy relative to littermate controls. In addition, levels of synaptophysin and spinophilin, proteins generally enriched in synapses and dendritic spines respectively, were elevated in the MPOA of maters. Dendritic morphology was also assessed in Golgi-impregnated brains of orchidectomized B6D2F1 males, and hybrid maters exhibited greater dendritic spine density in MPOA neurons. In sum, we show for the first time that retention of MSB in the absence of steroids is correlated with morphological differences in neurons.