The feeding behaviour of specialist butterflies may be affected by the mechanical and chemical characteristics of the tissues of their host-plants. Larvae of the butterfly, Battus polydamas ...archidamas feed only on Aristolochia chilensis, which contains aristolochic acids. We studied the oviposition pattern of adults and the foraging of larvae of B. polydamas archidamas over time in relation to variations in hardness of the substrate and concentration of aristolochic acids in different plant tissues. We further tested the effect of two artificial diets containing different concentrations of aristolochic acids on larval performance. B. polydamas archidamas oviposited mostly on young leaves and the larvae fed on this tissue until the second instar. Third instar larvae fed also on mature leaves and fourth and higher instars fed also on stems. Young leaves are softer and contain higher concentrations of aristolochic acids than mature leaves, and stems are both harder and contain a high concentration of aristolochic acids. Larvae reared on artificial diets containing a high concentration of aristolochic acids suffered less mortality and were heavier than those reared on a diet with a lower concentration of aristolochic acids, which suggests they are phagostimulatory. A strategy of host use regulated by aristolochic acid content and tissue hardness is discussed. PUBLICATION ABSTRACT
This study lays the groundwork for future lentivirus-mediated gene therapy in patients with Diamond Blackfan anemia (DBA) caused by mutations in ribosomal protein S19 (RPS19), showing evidence of a ...new safe and effective therapy. The data show that, unlike patients with Fanconi anemia (FA), the hematopoietic stem cell (HSC) reservoir of patients with DBA was not significantly reduced, suggesting that collection of these cells should not constitute a remarkable restriction for DBA gene therapy. Subsequently, 2 clinically applicable lentiviral vectors were developed. In the former lentiviral vector, PGK.CoRPS19 LV, a codon-optimized version of RPS19 was driven by the phosphoglycerate kinase promoter (PGK) already used in different gene therapy trials, including FA gene therapy. In the latter one, EF1α.CoRPS19 LV, RPS19 expression was driven by the elongation factor alpha short promoter, EF1α(s). Preclinical experiments showed that transduction of DBA patient CD34+ cells with the PGK.CoRPS19 LV restored erythroid differentiation, and demonstrated the long-term repopulating properties of corrected DBA CD34+ cells, providing evidence of improved erythroid maturation. Concomitantly, long-term restoration of ribosomal biogenesis was verified using a potentially novel method applicable to patients' blood cells, based on ribosomal RNA methylation analyses. Finally, in vivo safety studies and proviral insertion site analyses showed that lentivirus-mediated gene therapy was nontoxic.
Several studies have evaluated the relative contribution of various host-plant attributes to the species richness of the associated insect herbivores, with and without the inclusion of the phylogeny ...of the host species for Northern hemisphere trees. In general these studies reached the same conclusion: tree availability (range and abundance) was a good predictor of insect species richness, although chemical attributes of the trees were not tested. The present study evaluates the relative contribution of ecological attributes of host-plant species within the Southern hemisphere genus
Nothofagus, to the species richness of their associated insect fauna in South America and New Zealand. The variables included were: area of distribution (
a), including longitudinal (rln) and latitudinal ranges (rlt), architectural complexity (
c) and phytochemical attributes of the species, including chemical diversity (
d) and chemical uniqueness (
u). The analysis by independent contrasts revealed that the latitudinal range is an important factor, which explained the insect richness associated with
Nothofagus for all guilds and taxonomic orders, except for the sap feeders. Compared to the non-phylogenetic analyses, including host-plant phylogeny led to the inclusion of additional variables in the regression equations. Phytochemical uniqueness of the host plants was an important factor to explain insect species richness. For example,
Nothofagus alessandrii, the species with the most unique chemistry, had very few and mostly specialised herbivores, whereas
Nothofagus dombeyi, with the least unique chemistry, had the highest number of related insect species. We conclude that, in addition to geographic range and phylogenetic relatedness, studies of insect herbivore diversity must also examine plant chemical composition.
In mehreren Untersuchungen wurde der relative Beitrag der verschiedenen Eigenschaften von Wirtspflanzen auf die Artenvielfalt der assoziierten herbivoren Insekten bestimmt. Dies geschah unter und ohne Berücksichtigung der Phylogenie der Wirtsarten für Bäume der nördlichen Hemisphäre. Im Allgemeinen kamen diese Untersuchungen zum gleichen Schluss: die Verfügbarkeit der Bäume (Verbreitung und Häufigkeit) war ein guter Indikator der Artenvielfalt von Insekten, obwohl die chemischen Eigenschaften der Bäume nicht untersucht wurden. Die vorliegende Untersuchung bestimmt den relativen Beitrag der ökologischen Eigenschaften der Wirtspflanzenarten zur Artenvielfalt der assoziierten Insektenfauna innerhalb der in der südlichen Hemisphäre verbreiteten Gattung
Nothofagus in Südamerika und Neuseeland. Die berücksichtigten Variablen waren: Verbreitungsareal (
a), einschließlich der Verbreitung in Bezug auf die Längengrade (rln) und Breitengrade (rlt), die architektonische Komplexität (
c) und phytochemischen Eigenschaften einschließlich der chemischen Diversität (
d) und der chemischen Einzigartigkeit (
u). Die Analyse durch unabhängige Vergleiche ließ erkennen, dass die Verbreitung in Bezug auf die Breitengrade einen wichtigen Faktor darstellt, der die Artenvielfalt der Insekten, die mit
Nothofagus assoziiert sind, für alle Gilden und taxonomischen Ordnungen mit Ausnahme der saugenden Herbivoren erklärt. Im Vergleich zu Analysen ohne Berücksichtigung der Phylogenie führte die Berücksichtigung der Phylogenie der Wirtspflanzen zur Einbeziehung von zusätzlichen Variablen in die Regressiongleichungen. Die phytochemische Einzigartigkeit der Wirtspflanzen war ein wichtiger Faktor, der die Artenvielfalt der Insekten erklärt. So hatte z. B.
Nothofagus alessandrii, die Art mit der einzigartigsten Chemie, nur wenige und meistens spezialisierte Herbivore, während
Nothofagus dombeyi, mit einer wenig einzigartigen Chemie, die größte Anzahl verwandter Insektenarten hatte. Wir schließen daraus, dass Untersuchungen der Diversität herbivorer Insekten zusätzlich zur geographischen Verbreitung und der phylogenetischen Verwandschaft die chemischen Zusammensetzungen berücksichtigen müssen.
The Ras signaling pathway controls important cellular responses to growth factors, and somatic mutations in RAS genes and other components of the Ras pathway, such as PTPN11 (encoding the ...protein-tyrosine phosphatase SHP-2) and BRAF, are found in human malignancies. Ras proteins are guanosine nucleotide-binding proteins that cycle between active guanosine triphosphate (GTP)-bound and inactive guanosine diphosphate (GDP)-bound conformations. Neoplasia-associated Ras mutations frequently affect amino acids G12, G13, or Q61 and decrease the intrinsic guanosine triphosphatase (GTPase) activity by ten- to twentyfold. The GTPase activity is crucial for Ras inactivation by hydrolysis and release of a phosphate group from Ras.GTP to produce Ras.GDP. We and others have recently discovered germline mutations in the KRAS gene in individuals diagnosed with Noonan and cardio-facio-cutaneous (CFC) syndrome, two clinically overlapping disorders characterized by short stature, distinct facial anomalies, heart defects, and other abnormalities. Noonan syndrome-associated mutations V14I and T58I K-Ras activate Ras but have milder biochemical effects than somatic mutations encountered in cancers, offering an explanation why these K-Ras lesions are tolerated during embryonic development. Together with recent findings of BRAF, MEK1, and MEK2 mutations in CFC syndrome and HRAS mutations in Costello syndrome, another clinically related disorder, it has now become clear that Noonan-like features (short stature, relative macrocephaly, facial anomalies, learning difficulties) that are found in these three related disorders are a result of constitutive activation of the Ras-Raf-extracellular signal-regulated and mitogen-activated protein kinase pathway.
Nestmate recognition is a necessary capacity for the occurrence of discrimination between nestmate and non-nestmate individuals. In one-piece nesting termites, which nest and forage in a single piece ...of wood, nestmate recognition is poorly studied mainly because the probability of encountering exogenous individuals is low in comparison with separate-piece nesting termites. Previous work described that production of soldiers of
Neotermes chilensis
, a one-piece nesting termite, increased when the risk of invasion of their colony increased, for example when neighboring colonies were present in the same nesting substrate and members of different colonies met when digging galleries. If soldiers are to fulfill their defensive role under these circumstances, they should show nestmate recognition ability; moreover, based on work on other social insects, such nestmate recognition should be based on cuticular compounds (CC). Bioassays were performed in which a soldier of
N. chilensis
was confronted with a nestmate or non-nestmate primary reproductive, pseudergate or another soldier, and in which a soldier was confronted with untreated and with CC-deprived dead primary reproductives. The results showed that soldiers were indeed more aggressive toward non-nestmates than nestmates for all castes, and that this discrimination was mediated mainly by qualitative (simple matching coefficient) and quantitative (Renkonen index) differences in CC.
Decision-making during host selection by phytophagous insects has proved to be related to host range, with specialists taking faster decisions than generalists; however, this pattern fails to ...materialize in some host selection studies performed with aphids. Differences found in testing designs point to rearing effects on aphid host selection. To test whether specialization patterns derive from the nature of the aphid or as a consequence of rearing environment, host selection behaviours were compared between the generalist Myzus persicae (Sulzer) s.s. and its subspecies specialized on tobacco when reared on a common host and offered the choice of an alternative host and a non-host plant. Pre-alighting (host finding and attraction towards host volatiles) and post-alighting (leaf surface exploration and probing) behaviours did not differ between the generalist and the tobacco-specialist, except in the allocation of time to probing behaviour; furthermore, all specialists chose the host on which they performed best. Thus, although the specialist was not faster than the generalist, it showed a higher level of commitment to its preferred host plant.
Diamond-Blackfan anemia (DBA) is a rare congenital hypoplastic anemia that usually presents early in infancy and is inherited in 10% to 20% of cases. Linkage analysis has shown that DBA in many of ...both dominant and recessive DBA families mapped to chromosome 19q13.2 leading to the cloning of a gene on chromosome 19q13.2 that encodes a ribosomal protein, RPS19. However, subsequently, mutations of theRPS19 gene have only been identified in 25% of all patients with DBA. This study analyzed 14 multiplex DBA families, 9 of which had 19q13.2 haplotypes inconsistent with 19q linkage. A genome-wide search for linked loci suggested the presence of a second DBA locus in a 26.4-centimorgan (cM) interval on human chromosome 8p. Subsequently, 24 additional DBA families were ascertained and all 38 families were analyzed with additional polymorphic markers on chromosome 8p. In total, 18 of 38 families were consistent with linkage to chromosome 8p with a maximal LOD score with heterogeneity of 3.55 at D8S277 assuming 90% penetrance. The results indicate the existence of a second DBA gene in the 26.4-cM telomeric region of human chromosome 8p23.3-p22, most likely within an 8.1-cM interval flanked by D8S518 and D8S1825. Seven families were inconsistent with linkage to 8p or 19q and did not reveal mutations in the RPS19 gene, suggesting further genetic heterogeneity.
A modular system for the DNA‐directed immobilization of antibodies was applied to capture living cells on microstructured DNA surfaces. It is demonstrated in two different set‐ups, static incubation ...and hydrodynamic flow, that this approach is well suited for specific capture and selection of cells from culture medium. The adhered cells show intact morphology and they can be cultivated to grow to dense monolayers, restricted to the lateral dimensions of DNA spots on the surface. Owing to the modularity of surface biofunctionalization, the system can readily be configured to serve as a matrix for adhesion and growth of different cells, as demonstrated by specific binding of human embryonic kidney cells (HEK293) and Hodgkin lymphoma L540cy cells onto patches bearing appropriate recognition moieties inside a microfluidic channel. We therefore anticipate that the systems described here should be useful for fundamental research in cell biology or applications in biomedical diagnostics, drug screening, and nanobiotechnology.
DNA‐directed immobilization combined with a modular protein capture system enables arraying of living cells on solid substrates by static incubation and hydrodynamic flow processes. The adhered cells can be cultivated to form dense monolayers with lateral dimensions, determined by the DNA microstructure. This approach should be useful for cell biology studies, biomedical diagnostics, or drug screening.
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