Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
1.
Vet Ophthalmol ; 2023 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-37952127

RESUMEN

OBJECTIVES: To determine the prevalence of retinal lesions and describe the fundoscopic findings of retinopathy in Greyhound dogs in the Manawatu/Whanganui region of New Zealand. To examine possible associations between sex, age, and racing variables with retinopathy in the study population. To describe retinal histologic findings in seven Greyhounds with retinopathy in New Zealand. METHODS: Two hundred Greyhound dogs from the Manawatu/Whanganui region of New Zealand underwent fundoscopy and fundic photography to identify and score the degree of retinopathy. Associations between retinopathy and age, sex, as well as racing variables, were examined. Histologic examination of the retina was undertaken on the eyes of seven Greyhounds from the Manawatu and Canterbury regions previously diagnosed with retinopathy by fundoscopy. RESULTS: Fifty dogs (25.1%) were identified with retinopathy of varying degrees of severity. In at least one eye, 7.5% of dogs had mild retinopathy, 11.6% moderate retinopathy, and 6.0% severe retinopathy. Males were more likely to be affected in both eyes and with moderate or severe grades, than females. Increasing age was not associated with increased prevalence of retinopathy, nor increased grade of severity. Retinal histology identified multifocal retinal detachment in 5 of the 7 cases examined and other common lesions included choroidal necrosis and outer to full-thickness retinal atrophy in the absence of significant inflammation. CONCLUSIONS: Retinopathy is prevalent in Greyhounds in the Manawatu/Whanganui region of New Zealand, but more research is required to elucidate the etiopathogenesis. Consideration should be made to include mandatory eye health examination in racing Greyhound dogs.

2.
PLoS One ; 18(11): e0293083, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37939028

RESUMEN

Biodiversity loss is a major global challenge and minimizing extinction rates is the goal of several multilateral environmental agreements. Policy decisions require comprehensive, spatially explicit information on species' distributions and threats. We present an analysis of the conservation status of 14,669 European terrestrial, freshwater and marine species (ca. 10% of the continental fauna and flora), including all vertebrates and selected groups of invertebrates and plants. Our results reveal that 19% of European species are threatened with extinction, with higher extinction risks for plants (27%) and invertebrates (24%) compared to vertebrates (18%). These numbers exceed recent IPBES (Intergovernmental Platform on Biodiversity and Ecosystem Services) assumptions of extinction risk. Changes in agricultural practices and associated habitat loss, overharvesting, pollution and development are major threats to biodiversity. Maintaining and restoring sustainable land and water use practices is crucial to minimize future biodiversity declines.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Animales , Biodiversidad , Vertebrados , Invertebrados , Plantas , Extinción Biológica , Especies en Peligro de Extinción
3.
Nature ; 605(7909): 285-290, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35477765

RESUMEN

Comprehensive assessments of species' extinction risks have documented the extinction crisis1 and underpinned strategies for reducing those risks2. Global assessments reveal that, among tetrapods, 40.7% of amphibians, 25.4% of mammals and 13.6% of birds are threatened with extinction3. Because global assessments have been lacking, reptiles have been omitted from conservation-prioritization analyses that encompass other tetrapods4-7. Reptiles are unusually diverse in arid regions, suggesting that they may have different conservation needs6. Here we provide a comprehensive extinction-risk assessment of reptiles and show that at least 1,829 out of 10,196 species (21.1%) are threatened-confirming a previous extrapolation8 and representing 15.6 billion years of phylogenetic diversity. Reptiles are threatened by the same major factors that threaten other tetrapods-agriculture, logging, urban development and invasive species-although the threat posed by climate change remains uncertain. Reptiles inhabiting forests, where these threats are strongest, are more threatened than those in arid habitats, contrary to our prediction. Birds, mammals and amphibians are unexpectedly good surrogates for the conservation of reptiles, although threatened reptiles with the smallest ranges tend to be isolated from other threatened tetrapods. Although some reptiles-including most species of crocodiles and turtles-require urgent, targeted action to prevent extinctions, efforts to protect other tetrapods, such as habitat preservation and control of trade and invasive species, will probably also benefit many reptiles.


Asunto(s)
Conservación de los Recursos Naturales , Extinción Biológica , Reptiles , Caimanes y Cocodrilos , Anfibios , Animales , Biodiversidad , Aves , Mamíferos , Filogenia , Reptiles/clasificación , Medición de Riesgo , Tortugas
4.
Biochem Biophys Res Commun ; 589: 223-228, 2022 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-34929445

RESUMEN

Covalent protein complexes have been used to assemble enzymes in large scaffolds for biotechnology purposes. Although the catalytic mechanism of the covalent linking of such proteins is well known, the recognition and overall structural mechanisms driving the association are far less understood but could help further functional engineering of these complexes. Here, we study the Jo-In complex by NMR spectroscopy and molecular modelling. We characterize a transient non-covalent complex, with structural elements close to those in the final covalent complex. Using site specific mutagenesis, we further show that this non-covalent association is essential for the covalent complex to form.


Asunto(s)
Proteínas Bacterianas/química , Complejos Multiproteicos/química , Aminoácidos/metabolismo , Proteínas Bacterianas/metabolismo , Complejos Multiproteicos/metabolismo , Unión Proteica , Estabilidad Proteica , Espectroscopía de Protones por Resonancia Magnética , Streptococcus pneumoniae/metabolismo
5.
Anal Chem ; 93(11): 4818-4824, 2021 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-33711235

RESUMEN

Phosphorylated metabolites are omnipresent in cells, but their analytical characterization faces several technical hurdles. Here, we detail an improved NMR workflow aimed at assigning the high-resolution subspectrum of the phospho-metabolites in a complex mixture. Combining a pure absorption J-resolved spectrum (Pell, A. J.; J. Magn. Reson. 2007, 189 (2), 293-299) with alternate on- and off-switching of the 31P coupling interaction during the t1 evolution with a pure in-phase (PIP) HSQMBC experiment (Castañar, L.; Angew. Chem., Int. Ed. 2014, 53 (32), 8379-8382) without or with total correlation spectroscopy (TOCSY) transfer during the insensitive nuclei enhancement by polarization transfer (INEPT) gives access to selective identification of the individual subspectra of the phosphorylated metabolites. Returning to the initial J-res spectra, we can extract with optimal resolution the full trace for the individual phospho-metabolites, which can then be transposed on the high-resolution quantitative one dimensional spectrum.


Asunto(s)
Mezclas Complejas , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Flujo de Trabajo
6.
Sci China Life Sci ; 64(3): 492-493, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33511475
7.
Magn Reson (Gott) ; 2(2): 619-627, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-37905230

RESUMEN

The heteronuclear single quantum correlation (HSQC) experiment developed by Bodenhausen and Ruben (1980) in the early days of modern nuclear magnetic resonance (NMR) is without a doubt one of the most widely used experiments, with applications in almost every aspect of NMR including metabolomics. Acquiring this experiment, however, always implies a trade-off: simplification versus resolution. Here, we present a method that artificially lifts this barrier and demonstrate its application towards metabolite identification in a complex mixture. Based on the measurement of clean in-phase and clean anti-phase (CLIP/CLAP) HSQC spectra (Enthart et al., 2008), we construct a virtually decoupled HSQC (vd-HSQC) spectrum that maintains the highest possible resolution in the proton dimension. Combining this vd-HSQC spectrum with a J-resolved spectrum (Pell and Keeler, 2007) provides useful information for the one-dimensional proton spectrum assignment and for the identification of metabolites in Dreissena polymorpha (Prud'homme et al., 2020).

8.
Metabolites ; 10(6)2020 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-32570933

RESUMEN

The zebra mussel (Dreissena polymorpha) represents a useful reference organism for the ecotoxicological study of inland waters, especially for the characterization of the disturbances induced by human activities. A nuclear magnetic resonance (NMR)-based metabolomic approach was developed on this species. The investigation of its informative potential required the prior interpretation of a reference 1H NMR spectrum of a lipid-free zebra mussel extract. After the extraction of polar metabolites from a pool of whole-body D. polymorpha powder, the resulting highly complex 1D 1H NMR spectrum was interpreted and annotated through the analysis of the corresponding 2D homonuclear and heteronuclear NMR spectra. The spectrum interpretation was completed and validated by means of sample spiking with 24 commercial compounds. Among the 238 detected 1H signals, 53% were assigned, resulting in the identification of 37 metabolites with certainty or high confidence, while 5 metabolites were only putatively identified. The description of such a reference spectrum and its annotation are expected to speed up future analyses and interpretations of NMR-based metabolomic studies on D. polymorpha and to facilitate further explorations of the impact of environmental changes on its physiological state, more particularly in the context of large-scale ecological and ecotoxicological studies.

9.
Animals (Basel) ; 10(2)2020 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-32059554

RESUMEN

As the reliance upon automated systems in the livestock industry increases, technologies need to be developed which can be incorporated into these systems to monitor animal health and welfare. Infrared thermography (IRT) is one such technology that has been used for monitoring animal health and welfare and, through automation, has the potential to be integrated into automated systems on-farm. This study reports on an automated system for collecting thermal infrared images of calves and on the development and validation of an algorithm capable of automatically detecting and analysing the eye and cheek regions from those images. Thermal infrared images were collected using an infrared camera integrated into an automated calf feeder. Images were analysed automatically using an algorithm developed to determine the maximum eye and cheek (3 × 3-pixel and 9 × 9-pixel areas) temperatures in a given image. Additionally, the algorithm determined the maximum temperature of the entire image (image maximum temperature). In order to validate the algorithm, a subset of 350 images analysed using the algorithm were also analysed manually. Images analysed using the algorithm were highly correlated with manually analysed images for maximum image (R2 = 1.00), eye (R2 = 0.99), cheek 3 × 3-pixel (R2 = 0.85) and cheek 9 × 9-pixel (R2 = 0.90) temperatures. These findings demonstrate the algorithm to be a suitable method of analysing the eye and cheek regions from thermal infrared images. Validated as a suitable method for automatically detecting and analysing the eye and cheek regions from thermal infrared images, the integration of IRT into automated on-farm systems has the potential to be implemented as an automated method of monitoring calf health and welfare.

10.
Animals (Basel) ; 9(8)2019 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-31394802

RESUMEN

Respiration rate (RR) is a common measure of cattle health and welfare. Traditionally, measuring RR involves counting flank movements as the animal inhales and exhales with each breath. This method is often considered difficult, labour-intensive and impractical. We validated the use of infrared thermography (IRT) as an alternative method of non-invasively measuring RR in young calves. RR was simultaneously recorded in two ways: (1) by observing flank movements from video recordings; and (2) by observing thermal fluctuations around the nostrils during inhalations and exhalations from infrared recordings. For each method, the time taken to complete five consecutive breaths (a breath being a complete inhalation/exhalation cycle) was recorded and used to calculate RR (breaths/min). From a group of five calves, a total of 12 video recordings and 12 infrared recordings were collected. For each procedure, 47 sets of five consecutive breaths were assessed. The RRs measured from video recordings of flank movements and thermal fluctuations around the nostrils from infrared recordings were highly correlated (R2 = 0.93). Validated as a suitable method for recording RR, future research can now focus on the development of algorithms to automate the use of IRT to support its integration into existing automated systems to remotely monitor calf health and welfare.

11.
Anal Chem ; 91(6): 3959-3963, 2019 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-30767511

RESUMEN

Simultaneous detection of 1H and 31P NMR signals through a dual-detection scheme with two receivers allows monitoring of both the signals of a molecule and the pH of the solution through the resonance of the inorganic phosphate. We evaluate here the method in terms of sensitivity and ease of implementation and show that the additional information obtained without any loss of information or increase in measuring time can be of practical importance in a number of biochemical systems.

12.
J Dairy Sci ; 101(10): 9472-9482, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30122410

RESUMEN

The type of flooring in dairy cattle systems influences cows' health and welfare. Although concrete is common, the use of more compressible flooring, such as rubber, is increasing. Cows prefer to stand and walk on rubber surfaces than on concrete; however, it is largely unknown how walking and standing for longer periods of time influence muscle activity and fatigue. Therefore, we used measures of behavior and muscle activity to investigate the potential benefits of providing a rubber flooring surface to dairy cattle. Sixteen lactating Holstein cows were forced to stand on either concrete or rubber flooring for 1 or 3 h in a 2 × 2 crossover design. Surface electromyograms (SEMG) and skin surface temperature were used to evaluate muscle activity, fatigue, and movement of muscle activity between the hind legs. Activity of 2 muscles, the bicep femoris and middle gluteal, was assessed during both static contractions, when cows transferred weight to each hind leg, before and after 1 and 3 h of standing, and dynamic contractions, associated with steps and with shifts in weight without steps. In addition, we evaluated stepping rate, time between each step, feeding behavior, skin surface temperature, and latency to lie down after standing. Standing duration influenced both the behavior and muscle activity of cows. Stepping rate increased with standing time for cows on both flooring types. Static muscle activity parameters of the bicep femoris muscle were higher after 3 h of standing for cows standing on both flooring types (2.3 and 3.6% increases in median amplitude and median power frequency, respectively) compared with the change after 1 h and compared with baseline values before the standing treatment. Flooring type influenced the behavior and muscle activity of the cows, particularly during the first hour of exposure; cows standing on rubber had a higher stepping rate, shorter interval between steps, and higher number of SEMG shifts (muscle activity shifts with or without visible steps) than cows on concrete. There was no difference in skin surface temperature, feeding behavior, or latency to lie down between the treatments. The results show that standing on a rubber flooring caused a different initial behavioral response compared with standing on concrete; however, possible reasons for these changes are unclear. Standing for 3 h resulted in an increase in stepping rate and in some muscle activity parameters; however, the results regarding muscle fatigue in relation to flooring type are inconclusive.


Asunto(s)
Bovinos/fisiología , Pisos y Cubiertas de Piso , Vivienda para Animales , Goma , Animales , Conducta Animal , Femenino , Lactancia
13.
Front Plant Sci ; 7: 1395, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27695470

RESUMEN

Aploneura lentisci Pass. is endemic to the Mediterranean region where it is holocyclic, forming galls on its primary host, Pistacia lentiscus and alternating over a 2-year period between Pistacia and secondary hosts, principally species of Gramineae. This aphid is widely distributed in Australia and New Zealand on the roots of the common forage grasses, ryegrass (Lolium spp.) and tall fescue (Schedonorus phoenix) where it exists as permanent, anholocyclic, parthenogenetic populations. Previous studies have indicated that infestations of A. lentisci significantly reduce plant growth and may account for differences in field performance of Lolium perenne infected with different strains of the fungal endophyte Epichloë festucae var. lolii. These obligate biotrophs protect their host grasses from herbivory via the production of alkaloids. To confirm the hypothesis that growth of L. perenne is associated with the effect of different endophyte strains on aphid populations, herbage and root growth were measured over time in two pot trials that compared three fungal endophyte strains with an endophyte-free control. In both pot trials, aphid numbers were lowest on plants infected with endophyte strain AR37 at all sampling times. In plants infected with a common toxic strain naturalized in New Zealand, aphid numbers overall were lower than on uninfected plants or those infected with strain AR1, but numbers did not always differ significantly from these treatments. Populations on AR1-infected plants were occasionally significantly higher than those on endophyte-free. Cumulative foliar growth was reduced in AR1 and Nil treatments relative to AR37 in association with population differences of A. lentisci in both trials and root dry weight was reduced in one trial. In four Petri dish experiments survival of A. lentisci on plants infected with AR37 declined to low levels after an initial phase of up to 19 days during which time aphids fed and populations were similar to those on plants without endophyte. Aphids on AR37-infected plants became uncoordinated in their movement and developed tremors before dying suggesting a neurotoxin was responsible for their mortality. Results support the hypothesis that differences in A. lentisci populations due to endophyte infection status and strain affects plant growth.

14.
PLoS One ; 11(8): e0160640, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27529491

RESUMEN

Knowledge products comprise assessments of authoritative information supported by standards, governance, quality control, data, tools, and capacity building mechanisms. Considerable resources are dedicated to developing and maintaining knowledge products for biodiversity conservation, and they are widely used to inform policy and advise decision makers and practitioners. However, the financial cost of delivering this information is largely undocumented. We evaluated the costs and funding sources for developing and maintaining four global biodiversity and conservation knowledge products: The IUCN Red List of Threatened Species, the IUCN Red List of Ecosystems, Protected Planet, and the World Database of Key Biodiversity Areas. These are secondary data sets, built on primary data collected by extensive networks of expert contributors worldwide. We estimate that US$160 million (range: US$116-204 million), plus 293 person-years of volunteer time (range: 278-308 person-years) valued at US$ 14 million (range US$12-16 million), were invested in these four knowledge products between 1979 and 2013. More than half of this financing was provided through philanthropy, and nearly three-quarters was spent on personnel costs. The estimated annual cost of maintaining data and platforms for three of these knowledge products (excluding the IUCN Red List of Ecosystems for which annual costs were not possible to estimate for 2013) is US$6.5 million in total (range: US$6.2-6.7 million). We estimated that an additional US$114 million will be needed to reach pre-defined baselines of data coverage for all the four knowledge products, and that once achieved, annual maintenance costs will be approximately US$12 million. These costs are much lower than those to maintain many other, similarly important, global knowledge products. Ensuring that biodiversity and conservation knowledge products are sufficiently up to date, comprehensive and accurate is fundamental to inform decision-making for biodiversity conservation and sustainable development. Thus, the development and implementation of plans for sustainable long-term financing for them is critical.


Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales/economía , Costos y Análisis de Costo , Internacionalidad , Bases de Datos Factuales
15.
J Dairy Sci ; 98(9): 6226-35, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26188570

RESUMEN

Dairy cattle managed in some pasture-based systems, such as in New Zealand, are predominantly kept outdoors all year around but are taken off pasture for periods, especially in wet weather to avoid soil damage. The use of rubber matting for such stand-off practices is becoming more common to improve animal welfare, and our objective was to investigate the effects of different space allowances on cow behavior and physiology when managed temporarily on rubber mats during a weather-induced stand-off period. Thirty pregnant, nonlactating Holstein-Friesian dairy cows were divided into 6 groups of 5 and exposed to 6 treatments following a Williams designed 6×6 Latin square. The treatments consisted of 6 space allowances on a 24-mm rubber surface during a simulated weather-induced stand-off period: 3.0, 4.5, 6.0, 7.5, 9.0, and 10.5 m(2)/cow. The stand-off period consisted of 18 h in the treatment pens followed by 6 h at pasture to allow for their daily feed intake (no feed was available during stand-off, following normal farm practice), for 3 consecutive days, with 6 d of recovery on pasture between treatments. When cows had more space available during the stand-off period, they spent more time lying on the rubber mats and less time lying on pasture during their daily 6-h feed break. Mean lying times (24 h, pasture and rubber mats combined) for the different space allowances were for 3.0 m(2)=7.5 h, 4.5 m(2)=10.2 h, 6.0 m(2)=11.9 h, 7.5 m(2)=12.4 h, and 10.5 m(2)=13.8 h. At 6.0 m(2) of space allowance per cow, the animals spent similar times lying per 24 h as when the cows were on recovery on pasture in between treatments (11.9 and 11.2 h, respectively). Aggressive interactions and nonaggressive lying disturbances were more frequent at lower space allowances (aggressive interactions decreased by 35% from 3.0 to 4.5 m(2)/cow, with a slower decline thereafter). Cows were dirtier after the stand-off period, particularly at lower space allowances. All cows had higher gait scores after the stand-off period; however, this change was unaffected by space allowance and very minor. Stride length, plasma cortisol, and body weight were all unaffected by the stand-off period and space allowance. The results suggest that to reduce aggressive behavior and maintain adequate lying times, dairy cattle managed temporarily on rubber matting for up to 18 h per day, without feed, should have a space allowance of at least 4.5 to 6.0 m(2) per cow.


Asunto(s)
Conducta Animal , Postura , Bienestar del Animal , Animales , Peso Corporal , Bovinos , Industria Lechera/métodos , Femenino , Marcha , Nueva Zelanda , Embarazo
16.
Theriogenology ; 83(9): 1484-92, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25748246

RESUMEN

Viable lambs can be produced after transfer of in vitro-derived embryos from oocytes harvested from prepubertal lambs. However, this occurs at a much lower efficiency than from adult ewe oocyte donors. The reduced competence of prepubertal oocytes is believed to be due, at least in part, to deficiencies in cytoplasmic maturation. Differences in the cytoplasmic ultrastructure between prepubertal and adult oocytes have been described in the sheep, pig, and cow. Prepubertal lamb oocytes have been shown to have a different distribution of mitochondria and lipid droplets, and less mitochondria and storage vesicles than their adult counterparts. L-carnitine plays a role in supplying energy to the cell by transporting long-chain fatty acids into mitochondria for ß-oxidation to produce ATP. Both L-carnitine and its derivative acetyl-L-carnitine have been reported to increase the blastocyst rate of oocytes from mice, cows, and pigs, treated during IVM. L-carnitine has also been shown to increase mitochondrial biogenesis in adipose cells. Therefore, the aims of this study were to determine if treatment of oocytes from prepubertal lambs with acetyl-L-carnitine during IVM could increase the blastocyst rate and alter mitochondria, vesicle, or lipid droplet number, volume, or distribution. The blastocyst rate was doubled in prepubertal lamb oocytes treated with acetyl-L-carnitine when compared to untreated oocytes (10.0% and 4.6%, respectively; P = 0.028). Light microscopy, scanning electron microscopy, and stereology techniques were used to quantify organelles in untreated and acetyl-L-carnitine-treated lamb oocytes, and quantitative polymerase chain reaction methods were used to measure the mitochondrial DNA copy number. There were no differences in mitochondrial volume, number, or mitochondrial DNA copy number. Acetyl-L-carnitine treatment increased the cytoplasmic volume (P = 0.015) of the oocytes, and there were trends toward an increase in the vesicle volume (P = 0.089) and an altered distribution of lipid droplets (P = 0.076). In conclusion, acetyl-L-carnitine can be used to increase the in vitro blastocyst rate of juvenile oocytes and therefore to improve juvenile in vitro embryo transfer methods. These methods can be used for livestock improvement by increasing the rate of genetic gain. Further work is required to identify the contents of the vesicles and confirm the mode of action of acetyl-L-carnitine in improving oocyte competence.


Asunto(s)
Acetilcarnitina/farmacología , Blastocisto/efectos de los fármacos , ADN Mitocondrial/química , Dosificación de Gen/efectos de los fármacos , Oocitos/fisiología , Ovinos/fisiología , Animales , Desarrollo Embrionario/efectos de los fármacos , Fertilización In Vitro/veterinaria , Técnicas de Maduración In Vitro de los Oocitos/veterinaria , Mitocondrias/efectos de los fármacos , Oocitos/ultraestructura , Maduración Sexual , Ovinos/embriología , Ovinos/crecimiento & desarrollo
17.
Reprod Fertil Dev ; 27(3): 513-22, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24456710

RESUMEN

Oocytes from prepubertal animals have a reduced ability to undergo normal embryo development and produce viable offspring. The correct quantity, activity and cytoplasmic distribution of oocyte organelles are essential for oocyte maturation, fertilisation and subsequent embryo development. The aim of this study was to quantify the ultrastructural differences between oocytes from prepubertal lamb and adult ewes using electron microscopy and stereology. We also determined whether quantitative polymerase chain reaction (qPCR) methods give comparable estimates of mitochondrial number to stereology. Mean storage vesicle volume was greater in adult compared with lamb oocytes before IVM and decreased during maturation in both adult and lamb oocytes. Mitochondrial volume and number increased in adult oocytes during maturation; however, no increase was observed in lamb oocytes. Mitochondrial DNA copy number measured by qPCR showed no differences between adult and lamb oocytes. A different distribution of mitochondria was observed in lamb oocytes before maturation, while the percentage of hooded mitochondria increased during maturation in adult oocytes and decreased in the lamb. In conclusion, the present study has identified differences in the vesicles and mitochondria between adult and lamb oocytes from ewes that may contribute to reduced developmental competence in prepubertal oocytes.


Asunto(s)
Técnicas de Maduración In Vitro de los Oocitos/veterinaria , Mitocondrias/ultraestructura , Oocitos/ultraestructura , Factores de Edad , Animales , ADN Mitocondrial , Desarrollo Embrionario/fisiología , Femenino , Oocitos/crecimiento & desarrollo , Ovinos
18.
PLoS One ; 9(11): e113934, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25426636

RESUMEN

The world's governments have committed to preventing the extinction of threatened species and improving their conservation status by 2020. However, biodiversity is not evenly distributed across space, and neither are the drivers of its decline, and so different regions face very different challenges. Here, we quantify the contribution of regions and countries towards recent global trends in vertebrate conservation status (as measured by the Red List Index), to guide action towards the 2020 target. We found that>50% of the global deterioration in the conservation status of birds, mammals and amphibians is concentrated in <1% of the surface area, 39/1098 ecoregions (4%) and eight/195 countries (4%) - Australia, China, Colombia, Ecuador, Indonesia, Malaysia, Mexico, and the United States. These countries hold a third of global diversity in these vertebrate groups, partially explaining why they concentrate most of the losses. Yet, other megadiverse countries - most notably Brazil (responsible for 10% of species but just 1% of deterioration), plus India and Madagascar - performed better in conserving their share of global vertebrate diversity. Very few countries, mostly island nations (e.g. Cook Islands, Fiji, Mauritius, Seychelles, and Tonga), have achieved net improvements. Per capita wealth does not explain these patterns, with two of the richest countries - United States and Australia - fairing conspicuously poorly. Different countries were affected by different combinations of threats. Reducing global rates of biodiversity loss will require investment in the regions and countries with the highest responsibility for the world's biodiversity, focusing on conserving those species and areas most in peril and on reducing the drivers with the highest impacts.


Asunto(s)
Conservación de los Recursos Naturales/métodos , Especies en Peligro de Extinción , Extinción Biológica , Vertebrados , Animales , Biodiversidad , Conservación de los Recursos Naturales/estadística & datos numéricos , Especies en Peligro de Extinción/estadística & datos numéricos , Geografía , Vertebrados/fisiología
19.
PLoS One ; 9(8): e100173, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25111137

RESUMEN

BACKGROUND: An understanding of the conservation status of Madagascar's endemic reptile species is needed to underpin conservation planning and priority setting in this global biodiversity hotspot, and to complement existing information on the island's mammals, birds and amphibians. We report here on the first systematic assessment of the extinction risk of endemic and native non-marine Malagasy snakes, lizards, turtles and tortoises. METHODOLOGY/PRINCIPAL FINDINGS: Species range maps from The IUCN Red List of Threatened Species were analysed to determine patterns in the distribution of threatened reptile species. These data, in addition to information on threats, were used to identify priority areas and actions for conservation. Thirty-nine percent of the data-sufficient Malagasy reptiles in our analyses are threatened with extinction. Areas in the north, west and south-east were identified as having more threatened species than expected and are therefore conservation priorities. Habitat degradation caused by wood harvesting and non-timber crops was the most pervasive threat. The direct removal of reptiles for international trade and human consumption threatened relatively few species, but were the primary threats for tortoises. Nine threatened reptile species are endemic to recently created protected areas. CONCLUSIONS/SIGNIFICANCE: With a few alarming exceptions, the threatened endemic reptiles of Madagascar occur within the national network of protected areas, including some taxa that are only found in new protected areas. Threats to these species, however, operate inside and outside protected area boundaries. This analysis has identified priority sites for reptile conservation and completes the conservation assessment of terrestrial vertebrates in Madagascar which will facilitate conservation planning, monitoring and wise-decision making. In sharp contrast with the amphibians, there is significant reptile diversity and regional endemism in the southern and western regions of Madagascar and this study highlights the importance of these arid regions to conserving the island's biodiversity.


Asunto(s)
Conservación de los Recursos Naturales , Extinción Biológica , Reptiles , Animales , Especies en Peligro de Extinción/estadística & datos numéricos , Madagascar , Reptiles/clasificación , Riesgo , Análisis Espacial
20.
Philos Trans R Soc Lond B Biol Sci ; 366(1578): 2598-610, 2011 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-21844039

RESUMEN

A recent complete assessment of the conservation status of 5487 mammal species demonstrated that at least one-fifth are at risk of extinction in the wild. We retrospectively identified genuine changes in extinction risk for mammals between 1996 and 2008 to calculate changes in the International Union for Conservation of Nature (IUCN) Red List Index (RLI). Species-level trends in the conservation status of mammalian diversity reveal that extinction risk in large-bodied species is increasing, and that the rate of deterioration has been most accelerated in the Indomalayan and Australasian realms. Expanding agriculture and hunting have been the main drivers of increased extinction risk in mammals. Site-based protection and management, legislation, and captive-breeding and reintroduction programmes have led to improvements in 24 species. We contextualize these changes, and explain why both deteriorations and improvements may be under-reported. Although this study highlights where conservation actions are leading to improvements, it fails to account for instances where conservation has prevented further deteriorations in the status of the world's mammals. The continued utility of the RLI is dependent on sustained investment to ensure repeated assessments of mammals over time and to facilitate future calculations of the RLI and measurement against global targets.


Asunto(s)
Conservación de los Recursos Naturales/métodos , Ecosistema , Especies en Peligro de Extinción , Extinción Biológica , Mamíferos/crecimiento & desarrollo , Animales , Estudios Retrospectivos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...