Ultra‐frequent HRAS p.Q61R somatic mutation in canine acanthomatous ameloblastoma reveals pathogenic similarities with human ameloblastoma

Ameloblastoma is a locally aggressive odontogenic tumour that occurs in humans and dogs. Most ameloblastomas (AM) in humans harbour mutually‐exclusive driving mutations in BRAF, HRAS, KRAS, NRAS or FGFR2 that activate MAPK signalling, and in SMO that activates Hedgehog signalling. The remarkable clinical and histological similarities between canine acanthomatous ameloblastoma (CAA) and AM suggest they may harbour similar driving mutations. In this study, aimed at characterizing the mutational status of SMO, BRAF, HRAS, KRAS, NRAS and FGFR2 in CAA, we used RNA sequencing, Sanger sequencing and restriction fragment length polymorphism assays to demonstrate that 94% of CAA (n = 16) harbour a somatic HRAS p.Q61R mutation. The similarities in MAPK‐activating mutational profiles between CAA and AM implicate conserved molecular mechanisms of tumorigenesis, thus, qualifying the dog as a potentially useful model of disease. Given the relevance of RAS mutations in the pathogenesis of odontogenic tumours and other types of cancer, the results of this study are of comparative, translational, and veterinary value.     

Pathogenicity studies with the fungi Aphanomyces invadans, Achlya bisexualis, and Phialemonium dimorphosporum: induction of skin ulcers in striped mullet

Based on isolations from naturally infected fish in Florida, we investigated the role of the fungi Aphanomyces invadans, Achlya bisexualis, and Phialemonium dimorphosporum in the etiology of ulcerative mycosis (UM) in striped mullet Mugil cephalus. We injected healthy striped mullet subcutaneously with secondary zoospores of four oomycete isolates: two concentrations (50 and 115 zoospores/mL) of SJR (an endemic isolate of Aphanomyces invadans in American shad Alosa sapidissima from the St. Johns River); two concentrations each of CAL (25 and 65 zoospores/mL) and ACH (1,400 and 2,000 zoospores/mL; endemic isolates of Aphanomyces invadans and Achlyva bisexualis, respectively, in striped mullet from the Caloosahatchee River); and two concentrations of the ascomycete culture MTZ (2,500 and 3,500 zoospores/mL; endemic isolate of P. dimorphosporum from whirligig mullet M. gyrans in the Matanzas Inlet). All fish injected with either concentration of SJR developed granulomatous ulcers after 8 d and died within 21 d. Eighty percent (8/10) of fish injected with the high dose of CAL developed ulcers after 13 d and died within 28 d, but only 30% (3/10) of fish injected with the low dose of CAL developed ulcers. Four of the ulcerated fish died within 28 d, and the remaining fish were terminated after 32 d. Fish injected with zoospores of Aphanomyces invadans developed ulcers that were grossly and histologically similar to those observed in naturally infected striped mullet with UM from several estuaries or rivers in Florida. These hemorrhagic skin ulcers were characterized by myonecrosis and the presence of mycotic granulomas. None of the fish injected with ACH, MTZ, or sterile water developed ulcers. This study fulfilled Koch's postulates and demonstrated that ulcers could be experimentally induced in striped mullet after exposure via injection to secondary zoospores of an endemic Florida strain of Aphanomyces invadans.     

Hydrogeochemical Characteristics of Processes in the Temara Aquifer in Northwestern Morocco

The physico-chemical characteristics of the groundwater of the Temara aquifer were studied by means of piezometric mapping and determination of the ionic composition of the groundwater. In general, the agricultural activity is intense in the area, with water being pumped from numerous wells. Two aquifer formations can be distinguished which, over a wide area, are separated by layers of low permeability. The increased salinity at some points of the coastal zone is probably linked to the combined action of the washing out of Miocene marls, dissolution of carbonate rocks, agricultural pollution and seawater intrusion.     

The common bean landraces from Basilicata (Southern Italy): an example of integrated approach applied to genetic resources management

Ex situ conservation of genetic resources has contributed to the improvement of several food crops through utilisation of preserved germplasm, but it is not the only approach to safeguard genetic resources. Presently, in situ methods are being examined as effective complementary strategies to preserve diversity along with the dynamic environment. Examples of de facto on farm conservation, a form of in situ, have been described. However, their future is unpredictable without the relief of formal scientific projects or appropriate regulations. Recent European Community regulations have introduced the possibility to attribute marks of origin and quality to local typical products. These marks can be an important support to on farm maintenance of élite landraces of principal crops. In the frame of a collaboration between the Italian gene bank and a farm (of the agricultural research service of Basilicata region), an integrated approach, involving ex situ and on farm conservation, was adopted to safeguard common bean landraces from Basilicata. The main result of this project was the attribution of IGP (indication of geographic provenance), an European Community mark, to some tested landraces.     

2n gametes inSolanum tuberosum dihaploids

Pollen stainability over two years and microsporogenesis were investigated in seven dihaploids extracted fromSolanum tuberosum tetraploids (AVRDC-1287.19, Conchita, Merrimack and W231). Two dihaploids proved to be male-sterile and male gamete abortion is likely to be post-meiotic because a regular meiosis occurred. The other dihaploids proved to be partially male-fertile and 2n pollen producers, as well. Almost all clones showed predominantly the formation of parallel spindles. Correlations estimated between the observed abnormalities in spindle orientation and the meiotic products evidenced a high correlation between parallel/fused spindles and dyads. The dihaploids were also used as parents in crosses with tetraploids. One berry with 44 seeds was obtained from dihaploid AVI 24 used as pollen parent in 4x × 2x crosses. After 2x × 4x crosses, three dihaploids including the two male-sterile were found to be 2n egg producers. The formation of 2n gametes inS. tuberosum dihaploids is discussed in relation to a direct use of dihaploids in sexual polyploidization schemes to combine useful traits in a superior genotype at 4x level.     

Effect of host resistance on genetic structure of core and accessory chromosomes in Irish <Emphasis Type="Italic">Zymoseptoria tritici</Emphasis> populations

In agricultural pathosystems resistant cultivars are typically only temporarily effective, as widespread growth of said cultivars drives selection for pathogen genotypes capable of infecting them. A gene-for-gene interaction between Z. tritici and wheat has been demonstrated for one cultivar; however results of studies into the relevance of these interactions in the field remain inconsistent. Because genetic drift does not appear to occur between Z. tritici populations that are not widely geographically separated, according to neutral genetic theory if adaptation to different host cultivars is occurring, reduced genetic variation, and some differentiation between populations sourced from different cultivars should be observed. Selectively neutral microsatellite markers were used to genotype 260 isolates of Z. tritici taken from two naturally infected randomized block trials of four different cultivars, representing a spectrum of resistance to Z. tritici from susceptible to resistant. By calculating genetic parameters such as overall heterozygosity and F _ST from this genotypic data, the presented study aimed to determine if genetic drift or host selection is impacting on the genetic structure of the Irish Z. tritici population. Results indicated that diversity was distributed almost entirely within, rather than among populations, with little or no differentiation, and almost no clone isolates were present in the dataset. However this result was not reflected in the accessory chromosomes, where evidence of minor but significant genetic structure was found. This lack of structure in the core chromosomes and weak structure in the accessory chromosomes confirms that forces of genetic drift and selection are minor compared to sexual reproduction, in concurrence with multiple previous studies on other populations worldwide.     

Identification of a Pro-Angiogenic Potential and Cellular Uptake Mechanism of a LMW Highly Sulfated Fraction of Fucoidan from Ascophyllum nodosum

Herein we investigate the structure/function relationships of fucoidans from Ascophyllum nodosum to analyze their pro-angiogenic effect and cellular uptake in native and glycosaminoglycan-free (GAG-free) human endothelial cells (HUVECs). Fucoidans are marine sulfated polysaccharides, which act as glycosaminoglycans mimetics. We hypothesized that the size and sulfation rate of fucoidans influence their ability to induce pro-angiogenic processes independently of GAGs. We collected two fractions of fucoidans, Low and Medium Molecular Weight Fucoidan (LMWF and MMWF, respectively) by size exclusion chromatography and characterized their composition (sulfate, fucose and uronic acid) by colorimetric measurement and Raman and FT-IR spectroscopy. The high affinities of fractionated fucoidans to heparin binding proteins were confirmed by Surface Plasmon Resonance. We evidenced that LMWF has a higher pro-angiogenic (2D-angiogenesis on Matrigel) and pro-migratory (Boyden chamber) potential on HUVECs, compared to MMWF. Interestingly, in a GAG-free HUVECs model, LMWF kept a pro-angiogenic potential. Finally, to evaluate the association of LMWF-induced biological effects and its cellular uptake, we analyzed by confocal microscopy the GAGs involvement in the internalization of a fluorescent LMWF. The fluorescent LMWF was mainly internalized through HUVEC clathrin-dependent endocytosis in which GAGs were partially involved. In conclusion, a better characterization of the relationships between the fucoidan structure and its pro-angiogenic potential in GAG-free endothelial cells was required to identify an adapted fucoidan to enhance vascular repair in ischemia.