Untersuchungen zur Trinkwasservaccination gegen Newcastle Disease beim Birkwild (Lyrurus tetrix L., 1758)

European Journal of Wildlife Research - Bei 30 Birkhühnern wurde nach kontrolliert durchgeführter Trinkwasservaccination gegen Newcastle Disease (ND) (Erstimpfung mit Hitchner B1,...     

Changes in the Nuclear Envelope Environment Affect Spindle Pole Body Duplication in Saccharomyces cerevisiae

The Saccharomyces cerevisiae nuclear membrane is part of a complex nuclear envelope environment also containing chromatin, integral and peripheral membrane proteins, and large structures such as nuclear pore complexes (NPCs) and the spindle pole body. To study how properties of the nuclear membrane affect nuclear envelope processes, we altered the nuclear membrane by deleting the SPO7 gene. We found that spo7Δ cells were sickened by the mutation of genes coding for spindle pole body components and that spo7Δ was synthetically lethal with mutations in the SUN domain gene MPS3. Mps3p is required for spindle pole body duplication and for a variety of other nuclear envelope processes. In spo7Δ cells, the spindle pole body defect of mps3 mutants was exacerbated, suggesting that nuclear membrane composition affects spindle pole body function. The synthetic lethality between spo7Δ and mps3 mutants was suppressed by deletion of specific nucleoporin genes. In fact, these gene deletions bypassed the requirement for Mps3p entirely, suggesting that under certain conditions spindle pole body duplication can occur via an Mps3p-independent pathway. These data point to an antagonistic relationship between nuclear pore complexes and the spindle pole body. We propose a model whereby nuclear pore complexes either compete with the spindle pole body for insertion into the nuclear membrane or affect spindle pole body duplication by altering the nuclear envelope environment.THE nuclear envelope is composed of distinct outer and inner nuclear membranes. The outer nuclear membrane is continuous with the endoplasmic reticulum. The inner nuclear membrane is associated with a unique set of proteins, some of which mediate interactions between the nuclear envelope and chromatin (reviewed in Zhao et al. 2009). Nuclear pore complexes traverse both membranes and allow transport of proteins and solutes between the cytoplasm and the nucleus. The inner and outer nuclear membranes fuse in the region surrounding each nuclear pore complex.In animal cells, the nuclear envelope disassembles as cells enter mitosis and reassembles upon mitotic exit. Nuclear envelope breakdown allows the association of chromosomes with spindle microtubules, which are nucleated from centrosomes that reside in the cytoplasm. In contrast, certain types of fungi, such as the budding yeast Saccharomyces cerevisiae, undergo closed mitosis, where the nuclear envelope remains intact throughout the entire cell cycle. Closed mitosis is possible because the yeast centrosome-equivalent, the spindle pole body (SPB), is embedded in the nuclear envelope, allowing the SPB to nucleate both cytoplasmic and nuclear microtubules.SPB duplication requires a mechanism for inserting the new SPB into the nuclear envelope (reviewed in Jaspersen and Winey 2004). The new SPB begins to form in late G₁/early S phase as satellite material deposited on the cytoplasmic face of an electron-dense region of the nuclear envelope, called the half-bridge. The satellite material matures into a duplication plaque, which is then inserted into the nuclear membrane and becomes the daughter SPB. Many genes are known to be required for SPB duplication, and this process has been carefully examined cytologically (Rose and Fink 1987; Winey et al. 1991, 1993; Spang et al. 1995; Bullitt et al. 1997; Adams and Kilmartin 1999; Elliott et al. 1999; Schramm et al. 2000; Jaspersen et al. 2002; Nishikawa et al. 2003; Araki et al. 2006). However, the exact mechanisms by which SPB duplication and insertion occur remain a mystery.Equally unclear is how nuclear pore complexes are inserted into an intact nuclear envelope (reviewed in Hetzer and Wente 2009). For both the SPB and nuclear pore complexes, the inner and outer nuclear membranes must fuse to allow insertion into the nuclear envelope. Yeast and vertebrate nuclear pore complexes each have four pore membrane (POM) nucleoporins containing transmembrane domains. Other nucleoporins have motifs with potential for bending membranes or sensing membrane curvature. Thus, certain nuclear pore complex components may have the ability to alter the nuclear membrane or stabilize particular membrane conformations (Devos et al. 2004, 2006; Alber et al. 2007; Drin et al. 2007). It is interesting to note that, in S. cerevisiae, nuclear pore complexes are enriched in the vicinity of the SPB (Heath et al. 1995; Winey et al. 1997; Adams and Kilmartin 1999), but the significance of this phenomenon is not known. The SPB and nuclear pore complexes share at least two common components, the integral membrane protein Ndc1p and the small calcium-binding protein Cdc31p (Chial et al. 1998; Fischer et al. 2004). Ndc1p is thought to play a role in insertion of both SPBs and nuclear pore complexes into the nuclear membrane.SUN domain proteins are a conserved family of inner nuclear membrane proteins that interact with specific outer nuclear membrane proteins to form a physical bridge across the nuclear envelope (reviewed in Hiraoka and Dernburg 2009; Razafsky and Hodzic 2009). One of the components of the S. cerevisiae SPB is the SUN domain protein Mps3p. The N terminus of Mps3p is in the nucleoplasm, while the C terminus, containing the SUN domain, is found in the space between the inner and outer nuclear membranes. In addition to the SPB, Mps3p localizes to multiple foci at the nuclear periphery, and these two pools of Mps3p have distinct functions (Jaspersen et al. 2002, 2006; Nishikawa et al. 2003). At the SPB, Mps3p is required for half-bridge formation and early steps of SPB duplication, and cells compromised for Mps3p function accumulate in mitosis with a single SPB and a monopolar spindle (Jaspersen et al. 2002; Nishikawa et al. 2003). At the nuclear periphery, Mps3p is involved in tethering telomeres to the nuclear envelope in mitosis and meiosis, sequestering DNA double-strand breaks away from recombination factors, and associating with soluble chromatin proteins (Antoniacci et al. 2004, 2007; Bupp et al. 2007; Conrad et al. 2007, 2008; Oza et al. 2009; Schober et al. 2009).While many structural features of the yeast nucleus have been identified, little is known about how the physical properties of the nuclear membrane contribute to processes that occur at the nuclear envelope. As noted above, resident proteins of the nuclear envelope may affect nuclear membrane properties. In addition, the nuclear membrane is affected by altering lipid biosynthesis, for example, by inactivating the phosphatidic acid (PA) phosphohydrolase Pah1p or by inactivating the phosphates complex, made of Spo7p and Nem1p, which activates Pah1p. In the absence of Spo7p, Nem1p, or Pah1p, cells exhibit nuclear envelope extensions and extensive ER membrane sheets, and they also have altered membrane lipid composition, including a decrease in phosphatidylcholine and an increase in PA, phosphatidylethanolamine, and phosphatidylinositol (Siniossoglou et al. 1998; Santos-Rosa et al. 2005; Campbell et al. 2006; Han et al. 2006). These three proteins are unique among phospholipid biosynthesis proteins in their ability to affect nuclear morphology upon gene disruption (Han et al. 2008). A similar phenotype was seen upon overexpression of DGK1, which counteracts the activity of Pah1p by converting diacylglycerol to PA, leading to an increase in PA levels at the nuclear envelope (Han et al. 2008). Consistent with a conserved role for Pah1p in regulating nuclear envelope processes, deletion of either NEM1 or SPO7 is synthetically lethal with deletions of certain nucleoporin genes (Siniossoglou et al. 1998), and inactivation of the PAH1 homolog in Caenorhabditis elegans, LPIN-1, results in defects in nuclear envelope disassembly and reassembly (Golden et al. 2009; Gorjanacz and Mattaj 2009).To identify processes that are affected by altered nuclear membrane properties, we screened for pathways that are compromised in spo7Δ cells. We found that SPO7 inactivation strongly influences the SPB. By screening for proteins that could alleviate spo7Δ-induced SPB defects, we uncovered an unexpected inhibitory role for nucleoporins in SPB function, revealing that nuclear pore complexes, or components thereof, act antagonistically to the SPB in the nuclear envelope. Taken together, our findings indicate that the nuclear envelope environment is important for the function of protein complexes and biological processes occurring at the nuclear periphery.     

A self-feeding roller bottle for continuous cell culture

The concept of a self-feeding roller bottle that delivers a continuous supply of fresh media to cells in culture, which is mechanically simplistic and works with existing roller apparatuses, is presented here. A conventional roller bottle is partitioned into two chambers; one chamber contains the fresh culture media reservoir, and the other contains the cell culture chamber. A spiroid of tubing inside the fresh media reservoir acts as a pump when the bottle rotates on its horizontal axis, continuously delivering fresh media through an opening in the partition to the cell culture chamber. The modified bottle proved capable of maintaining steady-state cell densities of a hybridoma cell line over the 10-day period tested, although at lower densities than reached during batch operation due to the continuous volume dilution. Steady-state density proved to be controllable by adjusting the perfusion rate, which changes with the rotation rate of the bottle. Specific antibody production rate is as much as 3.7 times the rate in conventional roller bottles operating with intermittent batch feeding.     

Influence of the red blood cell Ca2+-ion concentration on the erythrocyte aggregation in stasis

Ca2+ ions were transported into the cell by incubation of the erythrocyte suspension with ionophore A23187, a lipophil electric neutral ion complexing substance. Erythrocyte aggregation could be increased twice, when doubling the intracellular Ca2+-ion concentration. Our measurements lead to the suggestion that an increase of the cytoplasmatic Ca2+ ion changes the physical and/or biochemical properties of the aggregation receptors on the membrane surface, i.e., cell-protein interactions are regulated by alteration of the intracellular Ca2+-ion concentration.     

Immunomodulatory effects of inactivated parapoxvirus ovis (ORF virus) on human peripheral immune cells: induction of cytokine secretion in monocytes and Th1-like cells

Inactivated parapoxvirus ovis (Orf virus; PPVO) recently displayed strong immunostimulating and modulating capacities in several animal models for acute and chronic virus infections through the induction of gamma interferon (IFN-gamma) as a key mediator of antiviral activity. The data presented in this work demonstrate that inactivated PPVO has strong effects on cytokine secretion by human immune cells, including the upregulation of inflammatory and Th1-related cytokines (IFN-gamma, tumor necrosis factor alpha [TNF-alpha], interleukin 6 [IL-6], IL-8, IL-12, and IL-18) as well as anti-inflammatory and Th2-related cytokines (IL-4, IL-10, and IL-1 receptor antagonist [IL-1ra]). Studies on the mechanism of action revealed virus particles to be the effective components of the preparation. The virus particles activate monocytes or other antigen-presenting cells (APC), e.g., plasmacytoid dendritic cells, through signaling over CD14 and a Toll-like receptor and the intracellular presence of certain PPVO-specific components. The activation of monocytes or APC is followed by the release of early proinflammatory cytokines (TNF-alpha, IL-6, and IL-8) as well as the Th1-related cytokines IL-12 and IL-18. Both IL-18 and IL-12 are involved in PPVO-mediated IFN-gamma release by T cells and/or NK cells. The proinflammatory response is accompanied by the induction of anti-inflammatory and Th2-related cytokines (IL-4, IL-10, and IL-1ra), which exert a limiting efffect on the inflammatory response induced by PPVO. We conclude that the induction of a natural immune response with physiologically significant amounts of different cytokines and with antiviral potential might provide advantages over existing antiviral immunotherapies.     

SHP2 and SOCS3 contribute to Tyr-759-dependent attenuation of interleukin-6 signaling through gp130

Interleukin-6 (IL-6) activates the Jak/STAT pathway as well as the mitogen-activated protein kinase cascade. Tyrosine 759 of the IL-6 signal-transducing receptor subunit gp130 has been identified as being involved in negative regulation of IL-6-induced gene induction and activation of the Jak/STAT pathway. Because this site is known to be a recruitment motif for the protein-tyrosine phosphatase SHP2, it has been suggested that SHP2 is the mediator of tyrosine 759-dependent signal attenuation. We recently observed that the suppressor of cytokine-signaling SOCS3 also acts through the tyrosine motif 759 of gp130. However, the relative contributions of SHP2 and SOCS3 to the repression of IL-6 signaling are not understood. Therefore, we designed experiments allowing the independent recruitment of each of these proteins to the IL-6-receptor complex. We show that receptor- and membrane-targeted SHP2 counteracts IL-6 signaling independent of SOCS3 binding to gp130. On the other hand, SOCS3 inhibits signaling in cells expressing a truncated SHP2 protein, which is not recruited to gp130. These data suggest, that there are two, largely distinct modes of negative regulation of gp130 activity, despite the fact that both SOCS3 and SHP2 are recruited to the same site within gp130.     

Antibiotic Resistance of Commensal Staphylococcus aureus and Coagulase-Negative Staphylococci in an International Cohort of Surgeons: A Prospective Point-Prevalence Study

Nasal colonization with antibiotic resistant bacteria represents both a risk factor for the colonized individual and their immediate contacts. Despite the fact that healthcare workers such as orthopedic surgeons are at a critical interface between the healthcare environment and an at-risk patient population, the prevalence of antibiotic resistant bacteria within the surgical profession remains unclear. This study offers a snapshot of the rate of nasal colonization of orthopedic surgeons with multi-resistant staphylococci including methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS). We performed a prospective, observational study obtained at a single time point in late 2013. The participants were active orthopedic, spine and head & neck surgeons from 75 countries. The prevalence of nasal carriage of the different bacteria and the corresponding 95% confidence interval were calculated. From a cohort of 1,166 surgeons, we found an average S. aureus nasal colonization rate of 28.0% (CI 25.4;30.6) and MRSA rate of 2.0% (CI 1.3;2.9), although significant regional variations were observed. The highest rates of MRSA colonization were found in Asia (6.1%), Africa (5.1%) and Central America (4.8%). There was no MRSA carriage detected within our population of 79 surgeons working in North America, and a low (0.6%) MRSA rate in 657 surgeons working in Europe. High rates of MRCoNS nasal carriage were also observed (21.4% overall), with a similar geographic distribution. Recent use of systemic antibiotics was associated with higher rates of carriage of resistant staphylococci. In conclusion, orthopedic surgeons are colonized by S. aureus and MRSA at broadly equivalent rates to the general population. Crucially, geographic differences were observed, which may be partially accounted for by varying antimicrobial stewardship practices between the regions. The elevated rates of resistance within the coagulase-negative staphylococci are of concern, due to the increasing awareness of their importance in hospital acquired and device-associated infection.     

Über den Begriff „Umwelt” in der Biologie

Summary The word Umwelt is not translated as yet and can perhaps not be translated. In its orginal and well known sense, inaugurated byUexküll, it means of the relations of an organism to its surroundings only those going over the receptive (sense-) organs and the effective organs (muscles, glands), while vegetative relations to the medium,e.g. respiration are excluded. The Umwelt-conception of ecology has always been a wider one, but by feeling only, without definition. H.Weber has tried to develop a general biological Umwelt-conception, including a 11 relations. In spite of this claim he states, the Umwelt of a species be only those external conditions which are indispensable for its life. Here is demonstrated that this conception is quite insufficient, especially because it does not contain so fundamentally important relations as the enemies of an organism and the reactions of the organism upon its surroundings (e.g. formation of limestone, humification of soil, turning of lakes into land by vegetation). Furthermore, that conception of Umwelt does not contain external conditions determinating the phenotype but not indispensable for the life of the species. A general biological conception of Umwelt, asWeber claims to have created, is impossible; the conception is divided in steps corresponding to its application in different branches of science. In physiologye.g. only the direct relations of an organism come in question, in epidemiology the vital relations only. The ecological conception is the most comprehensive (the real general one), containing all those parts of the surroundings to which an organism has direct or definite indirect relations, and is the complex of them.

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Résumé Le mot Umwelt n'est pas traduit et ne peut pas être traduit peut-être. Dans son sens original et bien connu, créé parUexküll, il comprend des relations d'un organisme à ses environs celles seulement, qui passent par les organes recepteurs (organes de sens) et les organes effectuants (muscles, glandes), pendant que les relations végétatives au médium, p.e. respiration ne sont pas comprises. L'écologie toujours a fait usuage du mot Umwelt dans un autre sens, mais intuitivement, sans définition. H.Weber a essayé de développer une conception Umwelt, dont il prétend la signification dans toute la biologie et qui comprenne toutes les relations. Malgré cette prétention,Weber comprend dans sa définition de la Umwelt d'une espèce ces relations seulement, qui sont indispensables pour leur vie. Ici est démontré que cette conception est tout à fait insuffisante, surtout pare qu'elle ne comprend pas des relations d'une importance si fondamentale comme l'ennemi d'un être vivant et les réactions de l'être vivant qui transforment ses environs (p.e. formation de pierre à chaux, humification du sol, transformation en terre d'un lac par la végétation). Y manquent aussi des conditions extérieures, déterminantes le phénotype, mais qui ne sont indispensables pour la vie de l'espèce. Une signification générale du mot Umwelt pour toute la biologie est impossible, la conception est divisée en échelons qui correspondent à l'application dans des branches différentes de la science. En physiologie p.e. il ne s'agit que des relations directes, en épidémiologie des relations d'importance vitale seulement. La signification écologique est la plus ample (la vraiment générale), comprenant toutes ces parties du milieu, auxquelles un organisme a des relations directes ou indirectes, dont la Umwelt est le complexe.