1,721,077 research outputs found
Pediatric patients with RASopathy-associated hypertrophic cardiomyopathy: the multifaceted consequences of PTPN11 mutations
Full text linkThe concomitant occurrence of hypertrophic cardiomyopathy and congenital heart defect in patients with RASopathies has previously been reported as associated to a worse clinical outcome, particularly closed to cardiac surgery. Different mechanisms of disease have been demonstrated to be associated with the two classes of PTPN11 mutations underlying Noonan syndrome and Noonan syndrome with multiple lentigines (also known as LEOPARD syndrome). Although differential diagnosis between these two syndromes could be difficult, particularly in the first age of life, we underline the relevance in discriminating these two disorders in terms of affected signaling pathway to allow an effective targeted pharmacological treatment
Development and Nutrition of the Braconid Wasp, Aphidius ervi in Aposymbiotic Host Aphids
No full textThis study aims at evaluating whether the bacterial endosymbionts
of the pea aphid, Acyrthosiphon pisum (Harris), may
be of any nutritional importance to the endophagous braconid
parasitoid Aphidius ervi Haliday. Aposymbiotic aphids, obtained
by rifampicin treatment on artificial diet, were parasitized,
and both parasitoid development and major changes
in the nitrogen-derived nutrients in the host hemolymph were
observed. A. ervi larvae developing in aposymbiotic pea aphids
showed a significant delay in reaching the adult stage and
the emerging adults showed a 50% weight reduction compared
to those emerging from symbiotic aphids. In the hemolymph
of parasitized symbiotic aphids, parasitism-specific proteins
of approximately 15 and 45 kD were detected, and their level
increased on day 5 and 6 after parasitoid oviposition. At that
stage, a significant increase in the free amino acid level was
observed, with glutamine showing the highest relative abundance.
In contrast, the hemolymph of aposymbiotic aphids did
not contain the two parasitism-specific proteins and no increase
in free amino acids was observed.
The results indicate that the bacterial endosymbionts in
parasitized pea aphids are of pivotal importance for the development
of A. ervi. Aposymbiotic aphids have a lower nutritional
suitability, showing a significant reduction in the
hemolymph of nitrogen-derived compounds of nutritional importance
to the developing parasitoid larva. The possible role
of Buchnera in nitrogen recycling is also discussed as a possible
strategy for optimizing the utilization of dietary nitrogen
by the parasitoid larva
Metabolic and symbiotic interactions in the pea aphid Acyrthosiphon pisum parasitised by the braconid Aphidius ervi.
No full textAphidius ervi Haliday (Hymenoptera, Braconidae) is an endophagous parasitoid of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera, Aphididae). This parasitoid strongly redirects host reproduction and metabolism to favour nutrition and development of its juvenile stages. Parasite-regulated biosynthesis and mobilization of nitrogen metabolites determine a significant increase of host nutritional suitability. The aim of the present study was mainly to investigate the temporal changes of A. pisum amino acid pools, as affected by A. ervi parasitism, and to assess the role of the aphid bacterial endosymbiont Buchnera in determining the observed changes. In parasitized aphids, we observed a very significant increase in total free amino acids, compared with synchronous non-parasitized controls, starting from day 4 after parasitization (+51%). This trend culminated with more than doubling the control value (+152%) on day 6 after parasitization. However, a significant “parasitism” effect was observed only for 10 of the 28 amino acids detected. Tyrosine accumulation was the most prominent parasitoid-induced alteration, with a fourfold increase over control levels registered on day 6. In parasitized hosts, the amino acid biosynthetic capacity of Buchnera was unaltered, or even enhanced for the phenolic pool, and contributed greatly to the definition and maintainance of host free amino acid pools. The hypertyrosinemic syndrome was not dependent on food supply of the aromatic nucleus but was induced by parasitism, which likely
enhanced the aromatic shuttle mediating phenylalanine transfer from bacteria to the host tissues, where tyrosine conversion occurs.
This process is likely associated with a selective disruption of the host’s functions requiring tyrosine, leading to the remarkable
accumulation of this amino acid. The possible mechanisms determining these parasitism-induced host alterations, and their nutritional significance for the developing parasitoid larva, are discussed
Genetics of atrioventricular canal defects
Full text linkAtrioventricular canal defect (AVCD) represents a quite common congenital heart defect (CHD) accounting for 7.4% of all cardiac malformations. AVCD is a very heterogeneous malformation that can occur as a phenotypical cardiac aspect in the context of different genetic syndromes but also as an isolated, non-syndromic cardiac defect. AVCD has also been described in several pedigrees suggesting a pattern of familiar recurrence. Targeted Next Generation Sequencing (NGS) techniques are proved to be a powerful tool to establish the molecular heterogeneity of AVCD. Given the complexity of cardiac embryology, it is not surprising that multiple genes deeply implicated in cardiogenesis have been described mutated in patients with AVCD. This review attempts to examine the recent advances in understanding the molecular basis of this complex CHD in the setting of genetic syndromes or in non-syndromic patients
EXCLUSION OF LINKAGE WITH CHROMOSOME 21 IN FAMILIES WITH RECURRENCE OF NON-DOWN ATRIOVEENTRICULAR CANAL.
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