Full‐length genome sequences of four polerovirus isolates infecting cucurbits in Taiwan determined from total RNA extracted from field samples     

D. Knierim  W. S. Tsai  T. C. Deng  S. K. Green  L. Kenyon 《Plant pathology》2013,62(3):633-641

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Effects of supplementation of medium with different antioxidants during in vitro maturation of bovine oocytes on subsequent embryo production          下载免费PDF全文

TC Sovernigo  PR Adona  PS Monzani  S Guemra  FDA Barros  FG Lopes  CLV Leal 《Reproduction in domestic animals》2017,52(4):561-569

The aim of this study was to assess the effects of different antioxidants on the levels of reactive oxygen species (ROS) and glutathione (GSH) in oocytes during in vitro maturation (IVM), as well as on the production of embryos. Oocyte of slaughterhouse‐derived cattle ovaries were placed in IVM with different antioxidants: quercetin (2 μM), cysteamine (100 μM), carnitine (0.5 mg/ml), vitamin C (50 μg/ml) or resveratrol (2 μM). Oocytes matured without any antioxidant supplementation were used as control. The oocytes were assessed for maturation rates and for ROS and GSH levels by fluorescence staining in 2′,7′‐dichlorodihydrofluorescein diacetate and Cell Tracker Blue, respectively. Embryo production was assessed in terms of cleavage, blastocysts and hatching rates and embryo cell numbers. The results expressed in arbitrary fluorescence units showed ROS reduction (p < .05) in the groups with quercetin (27.5 ± 3.4), vitamin C (27.1 ± 3.0) or resveratrol (28.1 ± 4.7), in comparison with those with cysteamine (34.9 ± 4.5), carnitine (34.6 ± 3.8) or to the control group (36.5 ± 5.2). GSH levels increased (p < .05) in cysteamine (63.5 ± 5.5) or carnitine (60.8 ± 4.4) groups in comparison with quercetin (52.7 ± 5.1), vitamin C (53.0 ± 3.8), resveratrol (53.1 ± 4.4) or to the control (49.6 ± 4.5). Nuclear maturation cleavage and hatched blastocysts rates did not differ (p > .05) between groups. However, blastocyst rates after in vitro fertilization in quercetin (53.5 ± 3.9%), vitamin C (52.1 ± 3.1%) resveratrol (54.2 ± 4.0%), cysteamine (52.4 ± 2.7%) or carnitine (54.2 ± 3.1%) groups were higher (p < .05) than in the control (47.2 ± 2.7%). Total cell numbers in embryos from the vitamin C, resveratrol, cysteamine or carnitine groups were higher than in quercetin and control groups, which were similar to each other. The results suggest that using antioxidants during IVM may reduce oxidative stress either by decreasing ROS levels directly or by increasing GSH levels in oocytes, depending on the type of antioxidant used. Overall, oxidative stress control during IVM with the antioxidants examined here improved blastocyst development with similar efficacy.  相似文献   

Identification of mungbean lines with tolerance or resistance to yellow mosaic in fields in India where different begomovirus species and different <Emphasis Type="Italic">Bemisia tabaci</Emphasis> cryptic species predominate     

R. M. Nair  M. Götz  S. Winter  R. R. Giri  V. N. Boddepalli  A. Sirari  T. S. Bains  G. K. Taggar  H. K. Dikshit  M. Aski  M. Boopathi  D. Swain  A. Rathore  V. Anil Kumar  E. C. Lii  L. Kenyon 《European journal of plant pathology / European Foundation for Plant Pathology》2017,147(2):349-364

The segmentation of symptoms during image analysis of diseased plant leaves is an essential process for detection and classification of diseases. However, there are challenges involved in the task, many of them related to the variability of image and host/symptom characteristics and conditions. As a result of those challenges, the methods proposed in the literature so far focus on a specific problem and are usually bounded by tight constraints regarding image capture conditions. This research explores a new automatic method for segmenting disease symptoms on plant leaves that was designed to be applicable in a wide range of situations. The proposed technique employs only color channel manipulations and Boolean operations applied on binary masks, thus being simpler and more robust compared to many previously described automatic methods. Its effectiveness is demonstrated by tests performed over a large database containing images of 77 different diseases of 11 plant species. A comparison with manual segmentation is also presented, further reinforcing the advantages of the proposed approach.  相似文献   

Consequences of Nitric Oxide Synthase Inhibition During Bovine Oocyte Maturation on Meiosis and Embryo Development     

KRL Schwarz  PRL Pires  THC de Bem  PR Adona  CLV Leal 《Reproduction in domestic animals》2010,45(1):75-80

The importance of nitric oxide synthase (NOS) in bovine oocyte maturation was investigated. Oocytes were in vitro matured with the NOS inhibitor N^w- l -nitro-arginine methyl-ester (10⁻⁷, 10⁻⁵ and 10⁻³  m l -NAME) and metaphase II (MII) rates and embryo development and quality were assessed. The effect of l -NAME (10⁻⁷  m ) during pre-maturation and/or maturation on embryo development and quality was also assessed. l -NAME decreased MII rates (78–82%, p < 0.05) when compared with controls without l -NAME (96%). Cleavage (77–88%, p > 0.05), Day 7 blastocyst rates (34–42%, p > 0.05) and total cell numbers in blastocysts were similar for all groups (146–171 cells, p > 0.05). Day 8 blastocyst TUNEL positive cells (3–4 cells) increased with l -NAME treatment (p < 0.05). For oocytes cultured with l -NAME during pre-maturation and/or maturation, Day 8 blastocyst development (26–34%) and Day 9 hatching rates (15–22%) were similar (p > 0.05) to controls pre-matured and matured without NOS inhibition (33 and 18%, respectively), while total cell numbers (Day 9 hatched blastocysts) increased (264–324 cells, p < 0.05) when compared with the controls (191 cells). TUNEL positive cells increased when NOS was inhibited only during the maturation period (8 cells, p < 0.05) when compared with the other groups (3–4 cells). NO may be involved in meiosis progression to MII and its deficiency during maturation increases apoptosis in embryos produced in vitro . Nitric oxide synthase inhibition during pre-maturation and/or maturation affects embryo quality.  相似文献   

Molecular identification of three distinct Polerovirus species and a recombinant Cucurbit aphid‐borne yellows virus strain infecting cucurbit crops in Taiwan     

D. Knierim  T. C. Deng  W. S. Tsai  S. K. Green  L. Kenyon 《Plant pathology》2010,59(5):991-1002

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Biophysical connectivity of snapper spawning aggregations and marine protected area management alternatives in Cuba     

Rodolfo Claro  Kenyon C. Lindeman  Andrew S. Kough  Claire B. Paris 《Fisheries Oceanography》2019,28(1):33-42

The ability of larvae to move beyond the spatial range of adult migrations can be critical to the resilience of populations that aggregate to spawn. We reviewed the literature and unpublished information on larval transport modeling, reef fish spawning aggregations, and marine protected area (MPA) management to identify alternatives for Cuban spawning site conservation. Larval transport information is available at annual and decadal scales for eight Cuban sites for five species of snappers. Connectivity patterns were examined: (a) within Cuban regions, (b) among Cuban regions, and (c) among other countries. We compared this information with the distribution of protected areas relative to spawning sites, site management attributes, and potential alternatives. Of eight focal spawning sites, seven are in protected areas and one is proposed. Southeast and north‐central Cuba had highest estimated within‐region retention levels. Southwest and northwest sites exported relatively more larvae out‐of‐region. Southern regions produced larvae that reached Jamaica, the Cayman Islands and Haiti. All northern regions can export larvae to the southern Bahamas. The regions and sites within are geomorphologically diverse with variable fishing and socio‐economic attributes. Information on stock status and protected area efficacy is limited and field assessments of aggregation status are needed for multispecies spawning sites. Few management plans address spawning conservation or network connectivity opportunities for MPAs. An alternative is development of one or more regional workgroups of protected area specialists, fishery scientists, expert fishers, and other stakeholders. Temporal closures of fisheries before and during spawning season could also amplify effectiveness of current gear‐ and zoning‐based management tools.  相似文献   

Two-fraction model of initial sediment motion in gravel-Bed rivers     

PR Wilcock 《Science (New York, N.Y.)》1998,280(5362):410-412

The prediction of sediment transport in gravel-bed rivers is essential to the management of land, water, and ecological resources in mountain regions. Dividing the bed sediment into two populations-sand and gravel-permits realistic and useful predictions of the onset of sediment transport. The critical flow initiating grain motion decreases rapidly with sand content over the transition from a gravel-framework bed to a sand-matrix bed. The two-fraction model provides a simple means of forecasting the movement of excess fine sediment supply. The model also helps to explain the development of the abrupt gravel-sand transition commonly observed in natural rivers.  相似文献   

Measuring the spin polarization of a metal with a superconducting point contact     

Soulen Jr RJ  JM Byers  MS Osofsky  B Nadgorny  T Ambrose  SF Cheng  Broussard C T Tanaka PR  J Nowak  JS Moodera  A Barry  JMD Coey 《Science (New York, N.Y.)》1998,282(5386):85-88

A superconducting point contact is used to determine the spin polarization at the Fermi energy of several metals. Because the process of supercurrent conversion at a superconductor-metal interface (Andreev reflection) is limited by the minority spin population near the Fermi surface, the differential conductance of the point contact can reveal the spin polarization of the metal. This technique has been applied to a variety of metals where the spin polarization ranges from 35 to 90 percent: Ni0.8Fe0.2, Ni, Co, Fe, NiMnSb, La0.7Sr0.3MnO3, and CrO2.  相似文献   

Cloning and sequencing of the ovine gamma-interferon gene   总被引：1，自引：0，他引：1  

AJ RADFORD  ALM HODGSON  JS ROTHEL  PR WOOD 《Australian veterinary journal》1991,68(3):82-84

Cytokines are major modulators of the immune system of all animals. The cloning and expression of recombinant cytokine genes have permitted the analysis of their immune function and role in the control of the immune response to disease and vaccination. While human, murine, and bovine genes have been cloned and sequenced, the cloning of ovine cytokine genes has not yet been reported. As sheep are of dominant economic importance to the Australian farming industry, it is of significance to clone and express these genes to facilitate the development of new and better vaccines and pharmaceuticals. We have initially selected ovine gamma-interferon (gamma-IFN) as a target cytokine gene. By the use of the polymerase chain reaction (PCR), using primers based on the bovine gamma-interferon sequence, we have amplified the ovine gamma-interferon gene from crude messenger RNA extracted from lymphocytes. After cloning and DNA sequencing the gene, we found that ovine gamma-IFN is 93% identical to bovine gamma-IFN in amino acid sequence. This result indicates that the PCR method will be a rapid and efficient means for cloning other ovine cytokine genes.  相似文献   

Identification of galegine, an isoprenyl guanidine, as the toxic principle of Schoenus asperocarpus (poison sedge)     

CR HUXTABLE  PR DORLING  SM COLEGATE 《Australian veterinary journal》1993,70(5):169-171

SUMMARY An Isoprenyl guanldine, galegine, was isolated from the Western Australian sedge Schoenus asperocarpus (Cyperaceae). Synthetic galegine was shown to reproduce the clinical and pathological features of poisoning by this plant. Preliminary results suggest that the massive thoracic effusion observed in sedge poisoning is the result of a direct effect on pulmonary vascular permeability.  相似文献