Structural Basis for Species Selectivity in the HIV-1 gp120-CD4 Interaction: Restoring Affinity to gp120 in Murine CD4 Mimetic Peptides

The first step of HIV-1 infection involves interaction between the viral glycoprotein gp120 and the human cellular receptor CD4. Inhibition of the gp120-CD4 interaction represents an attractive strategy to block HIV-1 infection. In an attempt to explore the known lack of affinity of murine CD4 to gp120, we have investigated peptides presenting the putative gp120-binding site of murine CD4 (mCD4). Molecular modeling indicates that mCD4 protein cannot bind gp120 due to steric clashes, while the larger conformational flexibility of mCD4 peptides allows an interaction. This finding is confirmed by experimental binding assays, which also evidenced specificity of the peptide-gp120 interaction. Molecular dynamics simulations indicate that the mCD4-peptide stably interacts with gp120 via an intermolecular β-sheet, while an important salt-bridge formed by a C-terminal lysine is lost. Fixation of the C-terminus by introducing a disulfide bridge between the N- and C-termini of the peptide significantly enhanced the affinity to gp120

Relatedness facilitates cooperation in the subsocial spider, Stegodyphus tentoriicola

<p>Abstract</p> <p>Background</p> <p>Cooperative hunting and foraging in spiders is rare and prone to cheating such that the actions of selfish individuals negatively affect the whole group. The resulting social dilemma may be mitigated by kin selection since related individuals lose indirect fitness benefits by acting selfishly. Indeed, cooperation with genetic kin reduces the disadvantages of within-group competition in the subsocial spider <it>Stegodyphus lineatus</it>, supporting the hypothesis that high relatedness is an important pre-adaptation in the transition to sociality in spiders. In this study we examined the consequences of group size and relatedness on cooperative feeding in the subsocial spider <it>S. tentoriicola</it>, a species suggested to be at the transition to permanent sociality.</p> <p>Results</p> <p>We formed groups of 3 and 6 spiders that were either siblings or non-siblings. We found that increasing group size negatively affected feeding efficiency but that these negative effects were reduced in sib-groups. Sib groups were more likely to feed cooperatively and all group members grew more homogenously than groups of unrelated spiders. The measured differences did not translate into differential growth or mortality during the experimental period of 8 weeks.</p> <p>Conclusion</p> <p>The combination of our results with those from previous studies indicates that the conflict between individual interests and group interests may be reduced by nepotism and that the latter promote the maintenance of the social community.</p

Protein content and glucosinolates from Moringa oleifera Lam. – New insights into an auspicious commodity

Moringa&nbsp; oleifera&nbsp; is&nbsp; considered&nbsp; to&nbsp; be&nbsp; one&nbsp; of&nbsp; the&nbsp; most&nbsp; valuable&nbsp; and&nbsp; beneficial crop tree species. The great nutritiousness is assigned to its&nbsp; high&nbsp; leaf&nbsp; protein&nbsp; content,&nbsp; and&nbsp; its&nbsp; health-promoting&nbsp; effect&nbsp; to&nbsp; the&nbsp; anti-carcinogenic&nbsp; properties&nbsp; of&nbsp; its&nbsp; genuine&nbsp; glucosinolates&nbsp; and&nbsp; their&nbsp; degradation products.From&nbsp; a&nbsp; plant&nbsp; physiological&nbsp; perception&nbsp; protein&nbsp; contents&nbsp; of&nbsp; 30%&nbsp; seem to be quite high. Accordingly, a reconsideration of these findings became necessary. The related inquiry unveils that also in the leaves&nbsp; of&nbsp; many&nbsp; other&nbsp; plant&nbsp; species&nbsp; such&nbsp; high&nbsp; protein&nbsp; contents&nbsp; are&nbsp; reported, provided that they are quantified by Kjeldahl nitrogen determinations. But, it is rather likely that the nitrogen accounting for the putative high protein contents is due to insoluble cell wall bound hydroxyproline-rich glycoproteins. Due to their extreme insolubility, these&nbsp; compounds&nbsp; cannot&nbsp; be&nbsp; digested&nbsp; easily,&nbsp; and &nbsp;thus,&nbsp; they&nbsp; do&nbsp; not&nbsp; contribute to the nutritiousness of M. oleifera leaves.In contrast to classical glucosinolates, those occurring in M. oleifera are characterized by an attachment of a rhamnose to the aglycone. In consequence, the products generated during the myrosinase-cata-lysed hydrolysis correspond to non-volatile rhamnosides of isothiocyanates. Since over time, olfactorily active substances emerge, the rhamnose moiety has to be cleaved off, putatively by a corresponding rhamnosidase

Modulation of mammalian cell behavior by nanoporous glass

The introduction of novel bioactive materials to manipulate living cell behavior is a crucial topic for biomedical research and tissue engineering. Biomaterials or surface patterns that boost specific cell functions can enable innovative new products in cell culture and diagnostics. This study investigates the influence of the intrinsically nano-patterned surface of nanoporous glass membranes on the behavior of mammalian cells. Three different cell lines and primary human mesenchymal stem cells (hMSCs) proliferate readily on nanoporous glass membranes with mean pore sizes between 10 and 124 nm. In both proliferation and mRNA expression experiments, L929 fibroblasts show a distinct trend toward mean pore sizes >80 nm. For primary hMSCs, excellent proliferation is observed on all nanoporous surfaces. hMSCs on samples with 17 nm pore size display increased expression of COL10, COL2A1, and SOX9, especially during the first two weeks of culture. In the upside down culture, SK-MEL-28 cells on nanoporous glass resist the gravitational force and proliferate well in contrast to cells on flat references. The effect of paclitaxel treatment of MDA-MB-321 breast cancer cells is already visible after 48 h on nanoporous membranes and strongly pronounced in comparison to reference samples, underlining the material's potential for functional drug screening

Qualifikations- und Arbeitsanalyse. Bericht über einen gemeinsamen Workshop des Bundesinstituts für Berufsbildungsforschung, des Instituts für Arbeitsmarktund Berufsforschung und des Referats Berufskunde der Bundesanstalt für Arbeit

"Mit dem Arbeitstreffen "Qualifikations- und Arbeitsanalyse" Ende 1973 wurde eine geplante Reihe regelmäßiger Veranstaltungen zwischen dem Bundesinstitut für Berufsbildungsforschung (BBF), dem Institut für Arbeitsmarkt- und Berufsforschung (IAB) sowie der für Berufskunde und berufliche Bildung zuständigen Unterabteilung der Bundesanstalt für Arbeit (BA) begonnen. Das Ziel dieser Zusammenarbeit liegt im intensivierten Austausch von Fragestellungen, theoretischen Ansätzen, Methoden und Forschungsinstrumentarien sowie in der verbesserten gegenseitigen Nutzung von Forschungsvorhaben und -ergebnissen. ... Es wurden zahlreiche Beiträge aus den beteiligten Institutionen und aus der Literatur zur Qualifikations- und Arbeitsanalyse darauf geprüft, wie man zu gemeinsam verwendbaren Begriffen, Kriterien und Nomenklaturen in einheitlich interpretierten Sachverhalten kommen kann. ... Aus dem Workshop folgt für die Forschung der beteiligten Institutionen, daß die ausgesprochen weitläufige qualifikationsund arbeitsanalytische Forschung nach einer Übergangsphase getrennt arbeitender Einzelvorhaben langfristig arbeitsteilig bewältigt werden sollte."Arbeitsanalyse, Qualifikation, Ausbildungsinhalt