1,720,982 research outputs found
Characterization of endophytic and symbiotic bacteria within plants of the endemic association Centaureetum horridae Mol.
No full textWe investigated the internal association of bacteria with Astragalus terraccianoi and Centaurea horrida, two endemic plants of the Mediterranean islands, forming the phytosociological association Centaureetum horridae, typical of windswept cliffs on the rocky shores of Asinara (Sardinia, Italy) and other limited locations. Sampling occurred in the protected natural park of the Asinara island. Roots and stems of the two plants and the root nodules of A. terraccianoi were surface sterilized in order to remove external and rhizospheric microbiota and to subsequently isolate the culturable bacterial communities. Plate counts revealed densities of endophytes between 3.7 × 102 and 2.8 × 104 colony forming units per gram of fresh weight. 16S rDNA sequencing revealed the occurrence of bacteria displaying high similarity with Actinobacterium sp., Paenibacillus sp., Rhizobium sp., Methylobacterium sp., Pedobacter panaciterrae, Aerococcus viridans, Stenotrophomonas rhizophila, Bacillus sporothermodurans, Bacillus pumilus, Bacillus simplex, Bacillus flexus, Streptomyces ciscaucasicus and Dyella sp. The putative nitrogen-fixing rhizobium symbiont of A. terraccianoi was identified for the first time. It turned out to belong to the slow-growing Bradyrhizobium genus and to share a 97% similarity with Bradyrhizobium canariense. It was found to be nonculturable and to coexist in nodules with a number of different endophytes
Mode of reproduction is detected by Parth1 e Sex1 SCAR markers in a wide range of facultative apomictic Kentucky bluegrass varieties
No full textGametophytic apomixis in Kentucky bluegrass (Poa pratensis L.) involves the parthenogenetic development of unreduced eggs from aposporic embryo sacs. Marker-assisted selection for the mode of reproduction in P. pratensis would avoid costly and time-consuming phenotypic progeny tests. We developed and tested two SCAR primer pairs that are associated with the mode of reproduction in P. pratensis. The SCAR primers identified the apomictic and sexual genotypes among progenies of sexual x apomictic crosses with very low bias. Furthermore, when tested on a wide range of Italian and exotic P. pratensis germplasm, they were able to unequivocally distinguish sexual from apomictic genotypes. This system should, therefore, allow new selection models to be set up in this species
Molecular characterization and expression of a divergent α-tubulin in planarian Schmidtea polychroa
No full textAgroindustrial by-products from tomato, grape and myrtle given at low dosage to lactating dairy ewes: effects on rumen parameters and microbiota
No full textThe inclusion of by-products in composite pellet feeds could be a strategy to recycle nutritional components and a commercial opportunity for feeds industries. Aim of this study was to evaluate if the use of small amount of dried by-products containing polyphenols could alter rumen fermentation parameters and microbiota in dairy ewes. Thirty-six ewes (9 animals per group) were fed control diet (CON), and diets supplemented with 100 g/d per animal of tomato pomace (TP), 100 g/d per animal of grape marc (GM), and 75 g/d per animal of exhausted myrtle berries (EMB). Treatment showed significant effects only on pH, whereas sampling time affected almost all rumen fermentation parameters. No differences in the proportion of any phylum were detected in GM group compared to CON group. TP, compared to CON, evidenced higher abundance of Proteobacteria phylum (counts of 4.86; log fold chain of 5.61) which was dominated by Acetobacteraceae family with Acetobacter genus. The supplementation of EMB resulted in higher abundance of Succinivibrionaceae and lower abundance of Veillonellaceae family. Furthermore, in EMB group the Paraprevotellaceae and Prevotellaceae families dominated the phylum of Bacteroidetes. This phylum was significantly different between EMB and CON diet (counts of 57.06; log fold change of 1.10). The estimated production of methane and rumen fermentation parameters were not affected by the diets. The supplementation in small doses of GM, TP and EMB in the diets of sheep did not evidence a clear variation in rumen fermentation parameters nor changes in the general structure of rumen microbiota.HIGHLIGHTS The agroindustrial by-products did not affect the rumen biochemical parameters. The structure of bacteria community was influenced by EMB diet. GM and TP diets did not increase rumen ammonia
Detection of selection signatures in Piemontese and Marchigiana cattle, two breeds with similar production aptitudes but different selection histories
Full text linkBackground
Domestication and selection are processes that alter the pattern of within- and between-population genetic variability. They can be investigated at the genomic level by tracing the so-called selection signatures. Recently, sequence polymorphisms at the genome-wide level have been investigated in a wide range of animals. A common approach to detect selection signatures is to compare breeds that have been selected for different breeding goals (i.e. dairy and beef cattle). However, genetic variations in different breeds with similar production aptitudes and similar phenotypes can be related to differences in their selection history.
Methods
In this study, we investigated selection signatures between two Italian beef cattle breeds, Piemontese and Marchigiana, using genotyping data that was obtained with the Illumina BovineSNP50 BeadChip. The comparison was based on the fixation index (Fst), combined with a locally weighted scatterplot smoothing (LOWESS) regression and a control chart approach. In addition, analyses of Fst were carried out to confirm candidate genes. In particular, data were processed using the varLD method, which compares the regional variation of linkage disequilibrium between populations.
Results
Genome scans confirmed the presence of selective sweeps in the genomic regions that harbour candidate genes that are known to affect productive traits in cattle such as DGAT1, ABCG2, CAPN3, MSTN and FTO. In addition, several new putative candidate genes (for example ALAS1, ABCB8, ACADS and SOD1) were detected.
Conclusions
This study provided evidence on the different selection histories of two cattle breeds and the usefulness of genomic scans to detect selective sweeps even in cattle breeds that are bred for similar production aptitudes
Molecular characterization and expression of a divergent tubulin in planarian Dugesia polychroa
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