68 research outputs found
Genetic diversity and physiological performance of portuguese wils beet (Beta vulgaris spp. maritima) from three contrasting habitats
The establishment of stress resilient sugar beets (Beta vulgaris spp. vulgaris) is an
important breeding goal since this cash crop is susceptible to drought and salinity. The
genetic diversity in cultivated sugar beets is low and the beet wild relatives are useful
genetic resources for tolerance traits. Three wild beet populations (Beta vulgaris spp.
maritima) from contrasting environments, Vaiamonte (VMT, dry inland hill), Comporta
(CMP, marsh) and Oeiras (OEI, coastland), and one commercial sugar beet (Isella variety,
SB), are compared. At the genetic level, the use of six microsatellite allowed to detect
a total of seventy six alleles. It was observed that CMP population has the highest
value concerning the effective number of alleles and of expected heterozygosity. By
contrast, sugar beet has the lowest values for all the parameters considered. Loci
analysis with STRUCTURE allows defining three genetic clusters, the sea beet (OEI
and CMP), the inland ruderal beet (VMT) and the sugar beet (SB). A screening test
for progressive drought and salinity effects demonstrated that: all populations were able
to recover from severe stress; drought impact was higher than that from salinity; the
impact on biomass (total, shoot, root) was population specific. The distinct strategies
were also visible at physiological level. We evaluated the physiological responses of the
populations under drought and salt stress, namely at initial stress stages, late stress
stages, and early stress recovery. Multivariate analysis showed that the physiological
performance can be used to discriminate between genotypes, with a strong contribution
of leaf temperature and leaf osmotic adjustment. However, the separation achieved and
the groups formed are dependent on the stress type, stress intensity and duration.
Each of the wild beet populations evaluated is very rich in genetic terms (allelic richness)
and exhibited physiological plasticity, i.e., the capacity to physiologically adjust to
changing environments. These characteristics emphasize the importance of the wild
beet ecotypes for beet improvement programs. Two striking ecotypes are VMT, which
is the best to cope with drought and salinity, and CMP which has the highest root to
shoot ratio. These genotypes can supply breeding programs with distinct goalsinfo:eu-repo/semantics/publishedVersio
Are Farm-Reared Quails for Game Restocking Really Common Quails (Coturnix coturnix)?: A Genetic Approach
The common quail (Coturnix coturnix) is a popular game species for which restocking with farm-reared individuals is a common practice. In some areas, the number of released quails greatly surpasses the number of wild breeding common quail. However, common quail are difficult to raise in captivity and this casts suspicion about a possible hybrid origin of the farmed individuals from crosses with domestic Japanese quail (C. japonica). In this study we used a panel of autosomal microsatellite markers to characterize the genetic origin of quails reared for hunting purposes in game farms in Spain and of quails from an experimental game farm which was founded with hybrids that have been systematically backcrossed with wild common quails. The genotypes of these quail were compared to those of wild common quail and domestic strains of Japanese quail. Our results show that more than 85% of the game farm birds were not common quail but had domestic Japanese quail ancestry. In the experimental farm a larger proportion of individuals could not be clearly separated from pure common quails. We conclude that the majority of quail sold for restocking purposes were not common quail. Genetic monitoring of individuals raised for restocking is indispensable as the massive release of farm-reared hybrids could represent a severe threat for the long term survival of the native species
Prisoners in Their Habitat? Generalist Dispersal by Habitat Specialists: A Case Study in Southern Water Vole (Arvicola sapidus)
Habitat specialists inhabiting scarce and scattered habitat patches pose interesting questions related to dispersal such as how specialized terrestrial mammals do to colonize distant patches crossing hostile matrices. We assess dispersal patterns of the southern water vole (Arvicola sapidus), a habitat specialist whose habitat patches are distributed through less than 2% of the study area (overall 600 km2) and whose populations form a dynamic metapopulational network. We predict that individuals will require a high ability to move through the inhospitable matrix in order to avoid genetic and demographic isolations. Genotypes (N = 142) for 10 microsatellites and sequences of the whole mitochondrial Control Region (N = 47) from seven localities revealed a weak but significant genetic structure partially explained by geographic distance. None of the landscape models had a significant effect on genetic structure over that of the Euclidean distance alone and no evidence for efficient barriers to dispersal was found. Contemporary gene flow was not severely limited for A. sapidus as shown by high migration rates estimates (>10%) between non-neighbouring areas. Sex-biased dispersal tests did not support differences in dispersal rates, as shown by similar average axial parent-offspring distances, in close agreement with capture-mark-recapture estimates. As predicted, our results do not support any preferences of the species for specific landscape attributes on their dispersal pathways. Here, we combine field and molecular data to illustrate how a habitat specialist mammal might disperse like a habitat generalist, acquiring specific long-distance dispersal strategies as an adaptation to patchy, naturally fragmented, heterogeneous and unstable habitats
The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance
INTRODUCTION
Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic.
RATIONALE
We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs).
RESULTS
Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants.
CONCLUSION
Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century
Protective effects of azarole polyphenolic extracts against oxidative damage using in vitro biomolecular and cellular models
The antioxidant activity of the different polyphenolic extracts prepared from Tunisian azarole, Crataegus azarolus and Crataegus monogyna (Rosaceae family) leaves, fruit peel, pulp and syrup was evaluated using cholesterol, liposome and rat liver-homogenate oxidation assays and cytotoxic activity in differentiated Caco-2, undifferentiated Caco-2, and B16F10 melanoma cells. Protective effects were observed against thermal-cholesterol degradation at 140 °C for 1 h, which depended on the concentration and the type of the extract. Moreover, the pre-treatment with the phenolic extracts preserved liposomes and rat liver-homogenate from oxidative induced damage by Cu2+ and Fe2+ at 37 °C for 24 h and 2 h, respectively. Azarole phenolics inhibited the oxidation of polyunsaturated fatty acids (PUFA) and limited the production of oxidized compounds. Furthermore, within tested concentrations (0.24-4.8 mg/mL), all extracts did not show any toxic effect on differentiated Caco-2 cells; while, they were found cytotoxic to cancer Caco-2 cells, except, extracts of pulp and syrup of C. monogyna. Using B16F10 melanoma cell model, only azarole pulp and syrup extracts were found toxic and induced the production of melanin in a dose-dependent manne
Population genetics suggests effectiveness of habitat connectivity measures for the European tree frog in Switzerland
1. Governmental authorities in many countries financially support the implementation of habitat
connectivity measures to enhance the exchange of individuals among fragmented populations. The
evaluation of the effectiveness of such measures is crucial for future management directions and can
be accomplished by using genetic methods.
2. We retraced the population history of the European tree frog in two Swiss river valleys (Reuss
and Thur), performed comprehensive population sampling to infer the genetic structure at 11
microsatellite markers, and used first-generation migrant assignment tests to evaluate the contemporary
exchange of individuals.
3. Compared with the Thur valley, the Reuss valley has lost almost double the number of breeding
sites and exhibited a more pronounced genetic grouping. However, similar numbers of contemporary
migrants were detected in both valleys. In the Reuss valley, 81% of the migration events
occurred within the identified genetic groups, whereas in the Thur valley migration patterns were
diffuse.
4. Our results show that the connectivity measures implemented in the Reuss valley facilitated effective
tree frog migration among breeding sites within distances up to 4 km. Nevertheless, the Reuss
valley exhibited high genetic differentiation, which reflected the impact of barriers to tree frog movement
such as the River Reuss. By contrast in the Thur valley, a larger number of breeding sites have
been preserved and high admixture indicated exchange of individuals at distances up to 16 km.
5. Synthesis and applications. We show that genetic methods can substantiate the effectiveness of
connectivity measures taken in conservation management at the landscape scale. We urge responsible
authorities from both river valleys to continue implementing connectivity measures and to
create a dense network of breeding sites, as spatial gaps of 8 kmare rarely traversed by tree frogs
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