Search results for "Specie"

2018

We present a taxonomic revision ofCremastosperma, a genus of Neotropical Annonaceae occurring in lowland to premontane wet forest, mostly in areas surrounding the Andean mountain chain. We recognise 34 species, describing five as new here: from east of the Andes,C.brachypodumPirie & Chatrou,sp. nov.andC.dolichopodumPirie & Maas,sp. nov., endemic to Peru;C.confusumPirie,sp. nov., from southern Peru and adjacent Bolivia and Brazil; andC.alticolaPirie & Chatrou,sp. nov., at higher elevations in northern Peru and Ecuador; and from west of the Andes,C.osicolaPirie & Chatrou,sp. nov.endemic to Costa Rica, the most northerly distributed species of the genus. We prov…

Polyamine Biosynthesis Engineering as a Tool to Improve Plant Resistance to Abiotic Stress

2015

Polyamines (PAs) are small polycationic molecules which are present in all living organisms. PAs have been involved in a wide array of metabolic plant processes, extending from development to stress protection. Most of this knowledge has been achieved through the observation of PA homeostasis and manipulation of plant PA levels mediated by different approaches. This chapter summarizes the approaches undertaken to demonstrate the relationship between PAs and the stress response and, in particular, how the genetic manipulation of polyamine levels has evolved in a useful tool for the enhancement of plant stress tolerance in many species, including crops. This chapter also includes the most rec…

Frequency-Dependent Selection in a Mammalian RNA Virus

1997

RNA viruses have been used as experimental systems to test evolutionary hypotheses such as Muller's ratchet (Chao 1990; Duarte et al. 1992, 1993; Clarke et al. 1993), the Red Queen hypothesis (Clarke et al. 1994), the nature of the adaptive topography (Elena, 1995; Elena et al. 1996), and the dynamics of adaptive evolution (Elena 1995; Novella et al. 1995). Two hypotheses which have received attention in virus studies are the competitive exclusion principle and frequency-dependent selection. The competitive exclusion principle (Hardin 1960) states that two populations or species competing for the same limiting resource cannot stably coexist because one competitor will displace the other. An…

2018

One of the most relevant characteristics of the extant Southern Ocean fauna is its resiliency to survive glacial processes of the Quaternary. These climatic events produced catastrophic habitat reductions and forced some marine benthic species to move, adapt or go extinct. The marine benthic species inhabiting the Antarctic upper continental shelf faced the Quaternary glaciations with different strategies that drastically modified population sizes and thus affected the amount and distribution of intraspecific genetic variation. Here we present new genetic information for the most conspicuous regular sea urchin of the Antarctic continental shelf, Sterechinus neumayeri. We studied the pattern…

mtDNA diversity in rabbit population from Sicily (Italy)

2017

The European rabbit Oryctolagus cuniculus (O.c) lives all over the world and it represents an important resource for many predators. It has been classified as a Near-Threatened species in the Red List of Vertebrates of Italy. It is present in mediterranean basin as two known subspecies: O.c. cuniculus and O.c. algirus. The mediterranean geographic distribution of the two subspecies is still not well known. In particular, in Sicily, lacking of deep studies, is based on the body size and morphological characteristics; there wasn’t a complete description of the actual existing subspecies and previous studies only reported the morphological characteristics of the sicilian rabbit population. In …

Variation in the COI gene of the freshwater pearl mussel Margaritifera margaritifera from River Vuokkijoki

2017

The freshwater pearl mussel Margaritifera margaritifera L. is one of the most endangered freshwater mussels in the world. Effective conservation of threatened species requires not only ecological, but also genetic information from the target species and populations. Since low genetic diversity can reduce the ability of a species to adapt to environmental changes, maintaining genetic diversity has been identified as one of the key elements in successful conservation programs. We examined genetic variation of the freshwater pearl mussel from the River Vuokkijoki, Karelia, Russia. We sequenced a fragment of the cytochrome c oxidase subunit I gene (COI) from 22 individuals and compared the data…

Additive effects of temperature and infection with an acanthocephalan parasite on the shredding activity of Gammarus fossarum (Crustacea: Amphipoda):…

2017

10 pages; International audience; Climate change can have critical impacts on the ecological role of keystone species, leading to subsequent alterations within ecosystems. The consequences of climate change may be best predicted by understanding its interaction with the cumulative effects of other stressors, although this approach is rarely adopted. However, whether this interaction is additive or interactive can hardly be predicted from studies examining a single factor at a time. In particular, biotic interactions are known to induce modifications in the functional role of many species. Here, we explored the effect of temperature on leaf consumption by a keystone freshwater shredder, the …

The Effect of Cadmium on Oxidative Stress in Beta vulgaris

2018

Abstract As a heavy metal, cadmium has strongly toxic effects on plants and can induce oxidative stress. It is absorbed by the roots and transported to the stems and leaves. The aim of the study was to evaluate the effect of various concentrations of cadmium on the metabolic activity of Beta vulgaris and assess the dependence of these processes on the content of metal in the plants. To demonstrate the effect of cadmium on metabolism, protein and photosynthetic pigment content, lipid peroxidation, and the activity of enzymes specific for oxidative stress in roots and shoots were measured. Seeds of B. vulgaris were treated with different concentrations of Cd supplied via a CdCl2 solution: 0 (…

Hemocyanin genes as indicators of habitat shifts in Panpulmonata?

2018

Hemocyanin is the primary respiratory protein for the majority of the Mollusca and therefore directly interfaces with the physiological requirements of each species and the environments to which they are adapted. Hemocyanin is therefore likely to have been evolutionarily imprinted by significant habitat shifts. In the gastropod clade Panpulmonata (>30,000 species) major realm transitions have occurred multiple times independently and may have contributed to the diversification of this group. Yet, little is known about the adaptive changes linked to these habitat shifts. In order to gain deeper insight into the evolution of panpulmonate hemocyanins and to infer possible impacts associated wi…

In vitro propagation of the relict laperinne’s olive (Olea europaea L. subsp. laperrinei)

2017

Olea europaea L. subsp. laperrinei (Oleaceae) is an endemic taxon of the mountainous regions of central Sahara, consisting of currently fragmented and small relict populations. The tree can propagate vegetatively or by seed, but no recent natural regeneration was observed in the Algerian massive populations, some of which are considered threatened with extinction. Sterile triploid individuals were also identified in some populations showing increasing vigour. As a result of its long persistence and despite its rarity, the Laperrine's olive is an iconic component of Saharan mountain ecosystems. The aim of this study is to develop an efficient micropropagation protocol for both diploid and tr…