Environmental determinants of perch (Perca fluviatilis) growth in gravel pit lakes and the relative performance of simple versus complex ecological predictors     

Leander Höhne  Miquel Palmer  Christopher T. Monk  Sven Matern  Robert Nikolaus  Ashley Trudeau  Robert Arlinghaus 《Ecology of Freshwater Fish》2020,29(4):557-573

Growth of fish is an important contributor to individual fitness as well as fish production. Explaining and predicting growth variation across populations is thus important from fundamental and applied perspectives, which requires knowledge about the ecological factors involved in shaping growth. To that end, we estimated environment-dependent von Bertalanffy growth models for 13 gravel pit lake populations of Eurasian perch (Perca fluviatilis) from north-western Germany. To identify the main drivers of perch growth, we evaluated the performance of 16 different biotic or abiotic lake variables in explaining growth variation among lakes. In addition, we compared growth predictions from the best-performing model incorporating “complex” variables that require intensive sampling effort, with a model using only “simple”, easily measurable lake variables (e.g. shoreline development factor). The derivation of a simple model aimed at future applications in typically data-poor inland fisheries, predicting expected growth potential from easily measurable lake variables. A model combining metabolic biomass of predators, maximum depth and shoreline development factor performed best in predicting perch growth variation across gravel pits. All three parameters in this model were positively related to perch growth. The best-performing simple model consisted only of the shoreline development factor. Length-at-age predictions from both models were largely identical, highlighting the utility of shoreline development factor in approximating growth potential of perch in gravel pits similar to our study lakes. Our results can be used to inform fisheries management and restoration efforts at existing or newly excavated gravel pit lakes.  相似文献   

Insect midgut structures and molecules as targets of plant‐derived protease inhibitors and lectins     

Thiago H Napoleo  Lidiane P Albuquerque  Nataly DL Santos  Isabella CV Nova  Thmarah A Lima  Patrícia MG Paiva  Emmanuel V Pontual 《Pest management science》2019,75(5):1212-1222

The midgut of insects is involved in digestion, osmoregulation and immunity. Although several defensive strategies are present in this organ, its organization and function may be disturbed by some insecticidal agents, including bioactive proteins like lectins and protease inhibitors (PIs) from plants. PIs interfere with digestion, leading to poor nutrient absorption and decreasing amino acid bioavailability. Intake of PIs can delay development, cause deformities and reduce fertility. Ingestion of PIs may lead to changes in the set of proteases secreted in the insect gut, but this response is often insufficient and results in aggravation of the malnutrition status. Lectins are proteins that are able to interact with glycoconjugates, including those linked to cell surfaces. Their effects on the midgut include disruption of the peritrophic matrix, brush border and secretory cell layer; induction of apoptosis and oxidative stress; interference with nutrient absorption and transport proteins; and damaging effects on symbionts. In addition, lectins can cross the intestinal barrier and reach the hemolymph. The establishment of resistant insect populations due to selective pressure resulting from massive use of a bioactive protein is an actual possibility, but this can be minimized by the multiple mode‐of‐action of these proteins, mainly the lectins. © 2018 Society of Chemical Industry  相似文献   

Grower adoption of insecticide resistance management practices increase with extension‐based program     

Ashley B Leach  Christine A Hoepting  Brian A Nault 《Pest management science》2019,75(2):515-526

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A PCR diagnostic assay for rapid detection of plant pathogenic pseudomonads     

Sandra B. Visnovsky  Preeti Panda  Kerry R. Everett  Ashley Lu  Ruth C. Butler  Robert K. Taylor  Andrew R. Pitman 《Plant pathology》2020,69(7):1311-1330

Molecular detection of phytopathogens is increasingly being applied to identify regulated organisms at the border in many parts of the world. However, even with molecular tests, complete phenotyping and identification of a strain is often time consuming and sometimes inconclusive. In this study, a leaf-based pathogenicity test was used to separate pseudomonads into two groups, Group A containing pathogens, and Group B containing saprotrophs. Comparative genomics of 56 pseudomonad genomes from different plant hosts (including 29 strains from kiwifruit) agreed with kiwifruit pathogenicity test results, placing pathogens into Group A and saprotrophs into Group B. Sixteen loci were found unique to Group A. A PCR assay was developed for amplification of one of these loci, the trehalose phosphatase gene. The generation of this 655 bp amplicon was associated with production of water-soaked lesions on inoculated kiwifruit leaves by pseudomonads in Group A. This test was validated for further strains from all seven pathogenic Pseudomonas phylogroups, non-pathogenic pseudomonads, and other bacterial genera. The sensitivity of the PCR was comparable to the limit of recovery of pseudomonads by culturing. This simple PCR assay could be used as part of a testing pipeline at the border and for general surveillance for screening plants with and without symptoms, offering the potential to detect uncharacterized pseudomonads that may pose a biosecurity risk. The method was shown to be able to rapidly identify pathogens cultured from plant material with symptoms, or, more importantly, to detect pathogens directly from plant tissue.  相似文献   

Abortion caused by neosporosis in cattle   总被引：2，自引：0，他引：2  

DL OBENDORF  N MURRAY  G VELDHUIS  BL MUNDAY  JP DUBEY 《Australian veterinary journal》1995,72(3):117-118

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Effect of Sperm Cryopreservation on the European Eel Sperm Viability and Spermatozoa Morphology     

JF Asturiano  F Marco-Jiménez  DS Peñaranda  DL Garzón  L Pérez  JS Vicente  M Jover 《Reproduction in domestic animals》2007,42(2):162-166

The main objective of the present work was to study the effect of cryopreservation of European eel sperm both on the sperm viability and the spermatozoa head morphology. Spermatozoa morphology was evaluated with computer-assisted morphology analysis after collection in fresh samples, after adding the freezing medium containing dimethyl sulfoxide as cryoprotectant and, finally, after the cryopreservation process and thawing. Cell viability was assessed, in both fresh and thawed samples, by Hoechst 33258 staining. Computer-assisted sperm analysis (CASA) was used to determine the percentage of motile cells and to measure motility parameters in sperm samples. A significant decrease of head perimeter (12.56%) and area (17.90%) was detected from spermatozoa in fresh to thawed samples, indicating that cells do not recover the original size after the cryopreservation process. CASA was used to measure the percentage of motile cells (51.9%) and spermatozoa motility parameters such as curvilinear, straight line and angular path velocities, as well as beating cross frequency. This technique was employed in the fresh sperm samples but proteins present at the freezing medium (L-alpha-phosphatidylcholine) made impossible to use this last technique in thawed samples. When sperm viability was assessed by Hoechst staining, a significant decrease of approximately 15% (73.10 vs 58.26%) of alive spermatozoa was registered from fresh to thawed samples. The percentage of motile cells measured by CASA in fresh samples (51.9%) was lower than the percentage of alive cells determined by Hoechst stainning, suggesting the existence of different batches of spermatozoa in different stages of development, even during the eight to tenth weeks of treatment, when the highest sperm quality was found.  相似文献   

Thoracic duct ligation and pericardectomy for treatment of idiopathic chylothorax     

Fossum TW  Mertens MM  Miller MW  Peacock JT  Saunders A  Gordon S  Pahl G  Makarski LA  Bahr A  Hobson PH 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(3):307-310

Chylothorax is a devastating disease, and the success rates from either medical or surgical management are less than satisfactory. In some animals with chylothorax, a thickening of the pericardium occurs that is associated with chronic irritation induced by chyle. We hypothesized that pericardial thickening would lead to increased right-sided venous pressures and that abnormal venous pressures would act to impede the drainage of chyle via lymphaticovenous communications after thoracic duct (TD) ligation. We also hypothesized that serosanguineous effusions that occurred after TD ligation could effectively be treated or prevented by pericardectomy in affected animals. TD ligation plus pericardectomy was performed in 17 animals, and pericardectomy alone was performed in an additional 3 animals that presented during a 5.5-year period to the Texas A&M University (College Station, TX). Nineteen animals presented for an evaluation of idiopathic chylothorax (9 dogs and 10 cats), and 1 dog presented for serosanguineous pleural fluid after TD ligation that had been performed elsewhere. Echocardiography was normal in all animals, except for a subjectively thickened pericardium in 7 cats and 6 dogs. Clinical signs of pleural fluid accumulation resolved in 10 of 10 dogs and in 8 of 10 cats after surgery. The overall success rate for the surgical treatment of chylothorax (ie, the resolution of pleural fluid accumulation) in this study was 90% (100% in dogs and 80% in cats). These data suggest that TD ligation in conjunction with pericardectomy has a favorable outcome in animals with idiopathic chylothorax.  相似文献   

Clinical efficacy of low‐level laser therapy on localized canine atopic dermatitis severity score and localized pruritic visual analog score in pedal pruritus due to canine atopic dermatitis     

Ashley N. Stich  Wayne S. Rosenkrantz  Craig E. Griffin 《Veterinary dermatology》2014,25(5):464-e74

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Use of Porcine Luteinizing Hormone at Oestrous Onset in a Protocol for Fixed‐Time Artificial Insemination in Gilts     

RR Ulguim  DL Fontana  JZ Rampi  ML Bernardi  I Wentz  FP Bortolozzo 《Reproduction in domestic animals》2014,49(5):756-760

The aim of this study was to evaluate the effect of porcine luteinizing hormone (pLH) given at oestrous onset in gilts, by different routes and doses, on the interval between onset of oestrus and ovulation (IOEO) and reproductive performance using a single fixed‐time artificial insemination (FTAI). A total of 153 gilts were submitted to oestrous detection at 8‐h intervals and assigned to three groups: control – without hormone application and inseminated at 0, 24 and 48 h after oestrous onset; VS2.5FTAI – 2.5 mg pLH by the vulvar submucosal route at oestrous onset and a single FTAI 16 h later; IM5FTAI – 5 mg pLH by the intramuscular route at oestrous onset and a single FTAI 16 h later. More VS2.5FTAI gilts (47.1%; p < 0.05) ovulated within 24 h after oestrous onset than control gilts (25.5%) whereas IM5FTAI gilts had an intermediate percentage (31.4%; p > 0.05). The IOEO tended to be shorter (p = 0.06) in VS2.5FTAI (30.2 ± 1.4 h) than in control (34.7 ± 1.4 h) gilts, but there was no difference (p > 0.05) between control and IM5FTAI (32.8 ± 1.4 h) gilts. Farrowing rate was not different (p > 0.05) among treatments. Total born piglets (TB) was lower (p < 0.05) in VS2.5FTAI (12.3 ± 0.4) than in control gilts (14.1 ± 0.4), whereas intermediate TB was observed in IM5FTAI gilts (13.3 ± 0.4). Due to the advancement of ovulation, reduction of the hormonal dose and the ease of application, the vulvar submucosal route would be the best option for FTAI protocols, but their negative impact on litter size remains to be elucidated. Taking into account the good fertility results obtained in IM5FTAI gilts whose ovulation was not advanced, the possibility of a single FTAI without any hormonal treatment should be further investigated, to establish reliable FTAI protocols for gilts.  相似文献   

Developing Tools to Encourage Private Forest Landowners to Participate in Early Successional Forest Habitat Management     

Ashley A. Dayer  Shorna Broussard Allred  Richard C. Stedman 《Human Dimensions of Wildlife》2014,19(4):355-370

Wildlife organizations often engage landowners in habitat management. Landowner typology research can provide suggestions for how to work with diverse types of landowners. We explored how typologies can inform selection of tools to engage landowners in early successional habitat (ESH) management. Using a survey, effectiveness of three kinds of tools were assessed: (a) basic needs, (b) learning, and (c) social. Across all types and typologies, learning tools were most likely to influence landowner behavior, whereas social tools (e.g., recognition) were least likely. Continuing adopters were the only type of landowners that reported basic needs tools would influence them at the same level as learning tools. In each typology, landowner types with higher behavioral intention were more likely to be influenced by all of the tools. Thus, tools may reinforce behaviors, rather than engage the unengaged. We suggest learning tools be initially prioritized to encourage ESH management.  相似文献