Diagnostic testing patterns of natural Mycobacterium paratuberculosis infection in pygmy goats

Thirteen pygmy goats (Capra hircus) from a herd naturally infected with Mycobacterium avium ss. paratuberculosis (MPTB) were monitored with 4 diagnostic assays for 2 to 15 mo. Cellular and humoral immune responses to the infection were assessed with assays of gamma interferon (IFNγ), serum antibody [enzyme-linked immunosorbent assay (ELISA) and agar gel diffusion (AGID)], and radiometric fecal culture. Microscopic examination and radiometric culture of tissue from 12 sites were performed at necropsy. Goats were considered infected if MPTB was isolated from any tissue sample collected at necropsy. Mycobacterial isolates were confirmed as MPTB with an IS900 polymerase chain reaction assay. Ten goats whose antemortem tests indicated infection carried heavy organism burdens at necropsy, both within and beyond the gastrointestinal system. False-negative ELISA, AGID, and/or culture results were obtained in 5 of the 10 confirmed cases during the study period. In 3 goats with sporadic fecal shedding of MPTB or detectable IFNγ response, or both, no abnormalities were detected at necropsy and no MPTB was isolated from the tissue samples; the antemortem fecal-culture and IFNγ results were thus considered false-positive. Diagnosticians should be alert to the possibility of both false-positive and false-negative test results for Johne's disease in goats. False-positive fecal-culture results may occur when a high prevalence of infection exists in the herd and the premises are likely to be heavily contaminated. The diverse antemortem testing patterns seen in these goats underscore the importance of using varied diagnostic assays serially or in parallel to increase the likelihood of identifying all infected goats.     

Testing assumptions of cost surface analysis—a tool for invasive species management

Applied ecology could benefit from new tools that identify potential movement pathways of invasive species, particularly where data are sparse. Cost surface analysis (CSA) estimates the permeability (friction) across a landscape and can be applied to dispersal modelling. Increasingly used in a diversity of applications, several fundamental assumptions that might influence the outputs of CSA (cost surfaces and least-cost pathways) have yet to be systematically examined. Thus, we explore two issues: the presumed relationship between habitat preferences and dispersal behaviour as well as the degree of landscape fragmentation through which an organism moves by modelling a total of 18 sensitivity and dispersal scenarios. We explored the effect of fragmentation by altering the friction values (generally assigned using expert opinion) associated with patch and linear features. We compared these sensitivity scenarios in two sites that differed in fragmentation. We also used eastern grey squirrels (Sciurus carolinensis) as an example invading species and compared diffusion models and two contrasting cost surface dispersal scenarios. The diffusion model underestimated spread because squirrels did not move randomly through the landscape. Despite contrasting assumptions regarding dispersal behaviour, the two cost surfaces were strikingly similar while the least-cost paths differed. Furthermore, while the cost surfaces were insensitive to changes in friction values for linear features, they were sensitive to assumptions made for patch features. Our results suggest that movement in fragmented landscapes may be more sensitive to assumptions regarding friction values than contiguous landscapes. Thus, the reliability of CSA may depend not only on the range of friction values used for patches but also the degree of contiguity in the landscape.     

Is risk consistent across tier‐based harvest control rule management systems? A comparison of four case‐studies

There can be substantial differences in data quality and quantity among fished species. Consequently, the quality and type of assessments can also vary substantially. However, all species, especially those that are targeted, need to be managed. Several jurisdictions have developed hierarchical tier systems that categorize stocks based on, for example, the data available for assessment purposes and/or the extent to which quantities on which management advice is based can be estimated. Four case‐studies (Australia's Southern and Eastern Scalefish and Shark Fishery, the USA west coast groundfishery, the USA Alaskan crab fishery and EU fisheries) are used to contrast the types of hierarchical tier systems available, and to assess the extent to which each system constrains risk to be equivalent among the tiers (termed risk equivalency). Only the Australian system explicitly aims to achieve risk equivalency. However, this intent has not been fully operationalized. Our review reveals that best practice is not to define tiers simply on data availability, but also on what the assessments based on those data are capable of estimating. In addition, clearly differentiating the quantification of uncertainty from how decision‐makers wish to address that uncertainty would simplify justification of buffers (the gap between the assessment‐produced target catch or effort and the final management decision that accounts for uncertainty and risk). Risk equivalency can be achieved using management strategy evaluation to select the values for control variables, which determine the buffer given the uncertainty associated with the assessment.     

The suitability of VIE tags to assess stock enhancement success in juvenile European lobsters (Homarus gammarus)

Assessments of stock enhancement programmes for European lobsters (Homarus gammarus) require mark‐recapture analysis of stocked individuals. However, established tag technology is deemed unsuitable for extensive use by many current lobster hatcheries, particularly upon the early juvenile stages. We tested the suitability of fluorescent Visible Implant Elastomer (VIE) tags for use in 5‐month‐old juvenile lobsters. Three treatment groups comprising 348 cultured lobsters in total were used to examine survival, growth and tag retention, and to assess mobility, shelter use and moulting behaviours. Tagging had no significant effect on lobster survival, growth, mobility, shelter use or moult frequency. Survival over 7 weeks was 75% among lobsters tagged with two elastomers, 76% in those with one elastomer and 74% among untagged controls. Mortality during moulting did not increase in tagged (6%) compared to untagged lobsters (9%). We found no evidence that VIE tags cause any negative effects that would be expected to inhibit survival upon wild release, but tag loss had reached 12% in both tagged treatments after 7 weeks and showed no sign of abating. Our study suggests that VIEs effectiveness in discerning cultured lobsters long after wild release may be limited when used in smaller juveniles.     

Blood lipid concentrations and lipoprotein patterns in captive and wild American black bears (Ursus americanus)

OBJECTIVE: To compare blood lipid concentrations and lipoprotein patterns for captive and wild American black bears (Ursus americanus). ANIMALS: 7 captive and 9 wild adult (> or = 4 years old) black bears. PROCEDURE: Blood was collected from 2 groups of captive black bears (groups A and B) and 1 group of wild black bears (group C). Blood triglyceride (TG) and cholesterol concentrations were compared among groups. Plasma lipoproteins were isolated by use of a self-generating gradient of iodixanol, and lipoprotein patterns were compared between groups A and B. RESULTS: Captive bears (mean +/- SD, 187.8 +/- 44.4 kg) weighed significantly more than wild bears (mean, 104.8 +/- 41.4 kg), but mean body weight did not differ between groups A and B. Mean blood TG concentrations for groups B (216.8 +/- 16.0 mg/dL) and C (190.7 +/- 34.0 mg/dL) were significantly higher than that of group A (103.9 +/- 25.3 mg/dL). Mean blood cholesterol concentration was also significantly higher for group B (227.8 +/- 8.2 mg/dL) than for groups A (171.7 +/- 35.5 mg/dL) or C (190.8 +/- 26.8 mg/dL). Mean very-low-density lipoprotein TG and low-density lipoprotein cholesterol concentrations were 2- and 3-fold higher, respectively, for group B, compared with concentrations for group A. CONCLUSIONS AND CLINICAL RELEVANCE: Blood lipid concentrations vary significantly among populations of black bears. Plasma lipoprotein patterns of captive bears differed significantly between colonies and may have reflected differences in diet or management practices.     

Nile tilapia broodfish fed high‐protein diets: Digestive enzymes in eggs and larvae

The aim of this study was to assess the activity of gastric, pancreatic and intestinal digestive enzymes during the embryonic and larval development of Nile tilapia (Oreochromis niloticus) GIFT strain Aqua America^® 1 obtained from a broodstock fed two levels of crude protein (CP). A total of 72 females and 24 males, 10 hapas, two CP levels (32% and 38%) and six phases of embryonic (cleavage, blastula, gastrula) and larval (hatching, 7 and 10 days post hatch, dph) stages were used. The eggs were collected in cleavage, blastula and gastrula stages, 300 mg was collected, and kept in cryogenic tubes in liquid nitrogen. For the samples at larval stage, the remaining eggs were separated according to crude protein level and kept in hatcheries and samples were collected on 7 and 10 dph the same way as before. A total of 48 samples were collected: at each protein level (32% and 38% CP), four samples were collected in each phase of embryonic and larval development. Statistical differences were not observed during embryonic development for acid proteases, trypsin, amylase and lipase activity at both levels of crude protein (32 and 38% CP). Differences for acid proteases were noticed on 7 dph; trypsin and amylase on 7 dph and 10 dph. Significant differences on blastula and 7 dph for protease; as for aminopeptidase, there was significant difference on 7 dph. The data indicated early appearance of digestive enzymes in Nile tilapia broodfish receiving 32% CP taking into account the rapid growth and development of this species.     

Heterochromatic silencing and HP1 localization in Drosophila are dependent on the RNAi machinery

Genes normally resident in euchromatic domains are silenced when packaged into heterochromatin, as exemplified in Drosophila melanogaster by position effect variegation (PEV). Loss-of-function mutations resulting in suppression of PEV have identified critical components of heterochromatin, including proteins HP1, HP2, and histone H3 lysine 9 methyltransferase. Here, we demonstrate that this silencing is dependent on the RNA interference machinery, using tandem mini-white arrays and white transgenes in heterochromatin to show loss of silencing as a result of mutations in piwi, aubergine, or spindle-E (homeless), which encode RNAi components. These mutations result in reduction of H3 Lys9 methylation and delocalization of HP1 and HP2, most dramatically in spindle-E mutants.     

ADP-Glucose Pyrophosphorylase Is Located in the Plastid and Cytosol in the Pulp of Tropical Banana Fruit (Musa acuminata)

Plant Foods for Human Nutrition - ADP-glucose pyrophosphorylase (AGPase) is a key enzyme of starch synthesis in seeds, tubers and fruits. UDP-glucose pyrophosphorylase (UGPase) is an important...     

Using social media as a cost‐effective resource in the photo‐identification of a coastal bottlenose dolphin community

1. Bottlenose dolphins encountered around the Irish coast are considered part of a wide‐ranging coastal community; however, knowledge on the significance of the north of Ireland for this species is limited by a lack of dedicated effort.
2. Through social media, the opportunity now exists to gather large volumes of citizen science data in the form of high‐quality images, potentially extending the spatial and temporal scope of photo‐identification studies.
3. The purpose of this study was to investigate social media as a data resource for photo‐identification studies and to provide a preliminary assessment of bottlenose dolphins in the north of Ireland. Specifically, the study sought to examine the photo‐identification data for spatial clustering.
4. The study identified 54 well‐marked individuals and provided evidence of potential year‐round occurrence, with successful re‐sightings throughout the study period (2007–2016). There was a geographic concentration of re‐sightings along the north of Ireland, suggestive of interannual site fidelity. These results provide scientific rationale for strategically targeting the north of Ireland in future research on the Irish coastal community.
5. For effective conservation of the bottlenose dolphin it is imperative that scientific research, and resultant management objectives, consider wide‐ranging communities such as the Irish coastal community. Our research highlights data collection via social media as a cost‐effective and scientifically valuable tool in the photo‐identification of coastal cetaceans. We recommend that this method is used in research on low‐density and wide‐ranging coastal cetaceans.