Estrogen receptor subtype β2 is involved in neuromast development in zebrafish (Danio rerio) larvae

Estrogens are known to play a role in both reproductive and non-reproductive functions in mammals. Estrogens and their receptors are involved in the development of the central nervous system (brain development, neuronal survival and differentiation) as well as in the development of the peripheral nervous system (sensory-motor behaviors). In order to decipher possible functions of estrogens in early development of the zebrafish sensory system, we investigated the role of estrogen receptor β₂ (ERβ₂) by using a morpholino (MO) approach blocking erβ₂ RNA translation. We further investigated the development of lateral line organs by cell-specific labeling, which revealed a disrupted development of neuromasts in morphants. The supporting cells developed and migrated normally. Sensory hair cells, however, were absent in morphants' neuromasts. Microarray analysis and subsequent in situ hybridizations indicated an aberrant activation of the Notch signaling pathway in ERβ₂ morphants. We conclude that signaling via ERβ₂ is essential for hair cell development and may involve an interaction with the Notch signaling pathway during cell fate decision in the neuromast maturation process.     

Loss of Drp1 function alters OPA1 processing and changes mitochondrial membrane organization

RNAi mediated loss of Drp1 function changes mitochondrial morphology in cultured HeLa and HUVEC cells by shifting the balance of mitochondrial fission and fusion towards unopposed fusion. Over time, inhibition of Drp1 expression results in the formation of a highly branched mitochondrial network along with “bulge”-like structures. These changes in mitochondrial morphology are accompanied by a reduction in levels of Mitofusin 1 (Mfn1) and 2 (Mfn2) and a modified proteolytic processing of OPA1 isoforms, resulting in the inhibition of cell proliferation. In addition, our data imply that bulge formation is driven by Mfn1 action along with particular proteolytic short-OPA1 (s-OPA1) variants: Loss of Mfn2 in the absence of Drp1 results in an increase of Mfn1 levels along with processed s-OPA1-isoforms, thereby enhancing continuous “fusion” and bulge formation. Moreover, bulge formation might reflect s-OPA1 mitochondrial membrane remodeling activity, resulting in the compartmentalization of cytochrome c deposits. The proteins Yme1L and PHB2 appeared not associated with the observed enhanced OPA1 proteolysis upon RNAi of Drp1, suggesting the existence of other OPA1 processing controlling proteins. Taken together, Drp1 appears to affect the activity of the mitochondrial fusion machinery by unbalancing the protein levels of mitofusins and OPA1.     

Social Learning Processes in Swiss Soil Protection—The ‘From Farmer - To Farmer’ Project

Social learning approaches have become a prominent focus in studies related to sustainable agriculture. In order to better understand the potential of social learning for more sustainable development, the present study assessed the processes, effects and facilitating elements of interaction related to social learning in the context of Swiss soil protection and the innovative ‘From Farmer - To Farmer’ project. The study reveals that social learning contributes to fundamental transformations of patterns of interactions. However, the study also demonstrates that a learning-oriented understanding of sustainable development implies including analysis of the institutional environments in which the organizations of the individual representatives of face-to-face-based social learning processes are operating. This has shown to be a decisive element when face-to-face-based learning processes of the organisations’ representatives are translated into organisational learning. Moreover, the study revealed that this was achieved not directly through formalisation of new lines of institutionalised cooperation but by establishing links in a ‘boundary space’ trying out new forms of collaboration, aiming at social learning and co-production of knowledge. It is argued that further research on social learning processes should give greater emphasis to this intermediary level of ‘boundary spaces’.

In silico study of kinetochore control, amplification, and inhibition effects in MCC assembly

Eukaryotic cells rely on a surveillance mechanism, the "Spindle Assembly Checkpoint"SACM in order to ensure accurate chromosome segregation by preventing anaphase initiation until all chromosomes are correctly attached to the mitotic spindle. In different organisms, a mitotic checkpoint complex (MCC) composed of Mad2, Bub3, BubR1/Mad3, and Cdc20 inhibits the anaphase promoting complex (APC/C) to initiate promotion into anaphase. The mechanism of MCC formation and its regulation by the kinetochore are unclear. Here, we constructed dynamical models of MCC formation involving different kinetochore control mechanisms including amplification as well as inhibition effects, and analysed their quantitative properties. In particular, in this system, fast and stable metaphase to anaphase transition can only be triggered when the kinetochore controls the Bub3:BubR1-related reactions; signal amplification and inhibition play a subordinate role. Furthermore, when introducing experimentally determined parameter values into the models analysed here, we found that effective MCC formation is not combined with complete Cdc20 sequestering. Instead, the MCC might bind and completely block the APC/C. The SACM might function by an MCC:APC/C complex rearrangement.     

Genome dynamics in major bacterial pathogens

Pathogenic bacteria continuously encounter multiple forms of stress in their hostile environments, which leads to DNA damage. With the new insight into biology offered by genome sequences, the elucidation of the gene content encoding proteins provides clues toward understanding the microbial lifestyle related to habitat and niche. Campylobacter jejuni, Haemophilus influenzae, Helicobacter pylori, Mycobacterium tuberculosis , the pathogenic Neisseria, Streptococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus are major human pathogens causing detrimental morbidity and mortality at a global scale. An algorithm for the clustering of orthologs was established in order to identify whether orthologs of selected genes were present or absent in the genomes of the pathogenic bacteria under study. Based on the known genes for the various functions and their orthologs in selected pathogenic bacteria, an overview of the presence of the different types of genes was created. In this context, we focus on selected processes enabling genome dynamics in these particular pathogens, namely DNA repair, recombination and horizontal gene transfer. An understanding of the precise molecular functions of the enzymes participating in DNA metabolism and their importance in the maintenance of bacterial genome integrity has also, in recent years, indicated a future role for these enzymes as targets for therapeutic intervention.     

Inhibition of human non-small cell lung cancers with a targeted cytotoxic somatostatin analog, AN-162

Human non-small cell lung cancers (NSCLCs) express receptors for somatostatin. The cytotoxic analog of somatostatin AN-162 (AEZS-124), consisting of doxorubicin linked to a somatostatin analog RC-121 binds to receptors for somatostatin and is targeted to tumors expressing these receptors. The aim of this study was to investigate the effect of targeted cytotoxic somatostatin analog AN-162 on a panel of human NSCLC cell lines (A549, H460, H838, H1299) in vitro (at 0.5–100 μM concentrations) and in vivo on H460 and H1299 NSCLCs xenografted into nude mice (at the dose of 2.5 μmol/kg, i.v., once a week). The expression of mRNA for somatostatin receptor subtypes was investigated by RT-PCR in cell lines and tumor tissues. Somatostatin receptor proteins were also characterized by ligand competition assay and Western blotting. AN-162 significantly decreased cell proliferation in vitro and tumor growth (p < 0.05 vs. all groups) of H460 and H1299 NSCLCs in vivo. Based on real-time PCR array data, AN-162 induced several apoptosis-related genes in vivo in both models. Our results suggest that cytotoxic somatostatin analog AN-162 (AEZS-124) should be considered for the further development of a therapy of patients with NSCLC.     

Poultry-Associated Salmonella enterica subsp. enterica Serovar 4,12:d:? Reveals High Clonality and a Distinct Pathogenicity Gene Repertoire

A European baseline survey during the years 2005 and 2006 has revealed that the monophasic Salmonella enterica subsp. enterica serovar 4,12:d:− was, with a prevalence of 23.6%, the most frequently isolated serovar in German broiler flocks. In Denmark and the United Kingdom, its serovar prevalences were 15.15% and 2.8%, respectively. Although poultry is a major source of human salmonellosis, serovar 4,12:d:− is rarely isolated in humans (approximately 0.09% per year). Molecular typing studies using pulsed-field gel electrophoresis and DNA microarray analysis show that the serovar is highly clonal and lacks genes with known contributions to pathogenicity. In contrast to other poultry-associated serovars, all strains were susceptible to 17 antimicrobial agents tested and did not encode any resistance determinant. Furthermore, serovar 4,12:d:− lacked the genes involved in galactonate metabolism and in the glycolysis and glyconeogenesis important for energy production in the cells. The conclusion of the study is that serovar 4,12:d:− seems to be primarily adapted to broilers and therefore causes only rare infections in humans.Salmonella spp. are major zoonotic food-borne pathogens which cause outbreaks and sporadic cases of gastroenteritis in humans worldwide (12). Depending on the serovar, cases of salmonellosis can differ substantially in severity (13). The primary sources of salmonellosis are food-producing animals, such as poultry, pigs, and cattle (30). The pathogen is spread by trade in animals and nonheated animal food products (10).A European baseline survey on the prevalence of Salmonella in commercial broiler flocks of Gallus gallus in 2005 and 2006 showed that in the European Union (EU), 23.7% of the broiler flocks were Salmonella positive (8). However, the Salmonella prevalences and serovar distribution varied widely among the EU member states. The five most frequently isolated Salmonella enterica serovars in Europe were those classically observed, like serovar Enteritidis (33.8%), serovar Infantis (22.0%), serovar Mbandaka (8.1%), serovar Hadar (3.7%), and serovar Typhimurium (3.0%). In Germany, the flock prevalence of Salmonella was 15.0% among the 377 broiler flocks investigated. In contrast to the well-known serovars described above, the predominating serovar was monophasic serovar 4,12:d:−, with a prevalence of 23.6%. This serovar was also isolated in Denmark and the United Kingdom, with prevalences of 15.2% and 2.8%, respectively.The German Salmonella National Reference Laboratory (NRL-Salmonella) has received 818 isolates of this serovar between 1998 and 2007, with peaks in 2001 (240 isolates) and 2004 (160 isolates), for diagnosis. Since 2005, the number has doubled annually, and the serovar obviously established itself well in poultry production lines. These isolates were found mostly in broilers (78%), occasionally in turkeys (11.6%) and feedstuff (8.4%), and rarely in pigs (1.3%) and cattle (0.6%). In contrast, infections in humans are only sporadic. During the last 10 years (1998 to 2007), the National Reference Centre for Salmonellae and Other Enterics located at the Robert-Koch Institute, Wernigerode branch, has received 55 strains of this serovar from sporadic human cases of salmonellosis and carriers in Germany (W. Rabsch, personal communication). Similarly, in Denmark, only two isolates in 1993 and in 2002 were isolated from humans (E. Møller Nielsen, Statens Serum Institut, Copenhagen, Denmark, personal communication).Subtyping food-borne pathogens is an approach often applied to facilitate the epidemiological investigation of outbreaks of gastrointestinal disease and to identify the source of entry into the food chain. Several molecular-based tools have been developed to type bacteria genotypically. Pulsed-field gel electrophoresis (PFGE) is currently the method of choice for the molecular subtyping of Salmonella serovars. It has been proven to be a useful discriminatory method which was standardized by the PulseNet Consortium (9). However, although this approach is certainly valuable, it does not reveal data on the gene repertoire and biological properties of a strain. To overcome this weakness, whole-genome DNA microarrays have successfully been applied in comparative genomic hybridizations for Salmonella (7, 24, 25). However, whole-genome arrays reflect only one genome of one strain. Because of many serovar or strain genome variations described for Salmonella, thematic arrays were developed, such as arrays specially targeting genes involved in resistance profiles (2, 17, 32), phage types (23), or serovars (33, 35). A condensed selection of 109 various Salmonella genetic markers comprising the detection of flagellar and somatic antigen-encoding genes, important virulence genes, phage-associated genes, and antibiotic resistance determinants have been used to show the usefulness of DNA microarrays for the discriminative characterization of Salmonella serovars (18).In this study, we elucidate the contradicting situation between the high prevalence in broilers and source attribution of broiler meat for humans and the low infection rates in humans of the serovar 4,12:d:− by genotypic characterization using PFGE and DNA microarray to determine the clonality, the pathogenic gene repertoire, and resistance determinants. These data give basic information to discuss the hazard potential of this serovar for humans. For that purpose, a new prototype of a Salmonella DNA microarray comprising 281 60-mer oligonucleotide probes was developed and validated in house.