Reconstructing the history of ocean wildlife around Ascension Island

1. In 2016, the UK government announced plans for a large‐scale Marine Protected Area around Ascension Island, a UK Overseas Territory in the South Atlantic.
2. To improve baselines for marine life to support ambitious conservation and assess change over time, archives were searched for historical accounts of wildlife from Ascension's discovery in 1501 to the present. For more recent changes, 139 interviews with past and present inhabitants were conducted.
3. Ascension's marine life has, from first discovery to the present, been consistently remarked upon for its exceptional abundance. Historical sources indicate declines in seabird and turtle populations from human exploitation and introduction of rats and cats. They are recovering with good management, although still below pre‐settlement abundance.
4. Interviews with residents indicate more recent changes, notably declines in catch per unit of fishing effort at popular shore angling sites, a decline in yellowfin tuna (Thunnus albacares) and increase in Galapagos sharks (Carcharhinus galapagensis).
5. What is very notable, however, based on the interviews, was that there was no temporal signal suggestive of recent systemic decline, in marked contrast to many parts of the world where recent wildlife declines have been pervasive and steep. Ascension represents a remarkable and immensely important centre of abundance in a sea of depletion and change, warranting full protection for all the island's waters.

     

Effect of Dietary Inclusion of N-Acetyl Cysteine on Mucus Viscosity and Susceptibility of Rainbow Trout, Oncorhynchus mykiss, and Atlantic Salmon, Salmo salar, to Amoebic Gill Disease

The treatment of amoebic gill disease (AGD) in cultured Atlantic salmon, Salmo salar L., using mucolytic agents has been previously reported. The agent L‐cysteine ethyl ester reduces salmonid mucus viscosity and potentially increases the flushing of the gill. In the present study, the effects of the mucolytic agent N‐acetyl cysteine (NAC) were assessed. Cutaneous mucus from rainbow trout, Oncorhynchus mykiss Walbaum, and Atlantic salmon was shown to have reduced viscosity when mixed in vitro with 100 or 200 μg/mL NAC. Saltwater‐acclimated rainbow trout and Atlantic salmon were fed an oil‐incorporated, NAC‐medicated diet (8 g NAC/kg diet) for up to 24 d and challenged with inoculation of 300 cells/L Neoparamoeba spp., the etiological agent of AGD. Control fish were fed normal oil‐coated pellets and received no NAC. NAC medication failed to reduce the severity of gill lesions associated with AGD even though the mucus viscosity from medicated fish was less than that of controls. Oral NAC medication does not appear to be an effective method for controlling AGD in salmonids despite reducing cutaneous mucus viscosity.     

Pathogens of zoonotic and biological importance in roe deer (Capreolus capreolus): Seroprevalence in an agro-system population in France

Antibody prevalence for several infectious and parasitic diseases in a population of roe deer (Capreolus capreolus) inhabiting a mixed agricultural landscape (south of France) has been analyzed. Serological analyses with ELISA in 245 animals captured from 2008 to 2012 has been performed. We found a high prevalence of Toxoplasma gondii (46.4%), Chlamydophila abortus (17.27%) and Coxiella burnetii (11.26%) compared to other studies in Europe. Seroprevalence varied strongly among years for T. gondii (27–91%), C. abortus (0–42%) and C. burnetii (0–27%). T. gondii prevalence was lower in juvenile females, compared to juvenile males and adults of both sexes. Other pathogens had low prevalences: Neospora caninum (1.56%), Bovine herpesvirus 1 (1.17%, 2008/09; 1.1%, 2010/11), Mycoplasma agalactiae (1.45%, 2009/10), Mycobacterium avium subsp. paratuberculosis (0.9%) and Slow viruses (CAEV–MVV) (0.15%, 2008/10; 0%, 2011/12). Antibodies to bluetongue virus and pestiviruses were not found in any individual.     

Development of two species-specific primer sets to detect the cereal cyst nematodes Heterodera avenae and Heterodera filipjevi

Twelve Heterodera species are of major economic significance in wheat and barley. Of these, H. avenae, H. filipjevi and H. latipons are among the most important ones, and sometimes coexist. The identification of Heterodera species using morphological characteristics is time consuming, requires specialized skill and can be imprecise, especially when they occur mixed in field populations. Molecular techniques can provide a more accurate way for nematode identification. This study reports the results of experiments targeting the mitochondrial cytochrome oxidase subunit 1 (COI) gene to develop species-specific primers that could be used for the identification of H. avenae and H. filipjevi. The COI gene of 9 Heterodera spp. and Punctodera punctata was partially sequenced and the resultant sequences were aligned to find unique sites suitable for the design of primers. The alignment showed variability between H. avenae, H. filipjevi and other Heterodera species. Two sets of species-specific primers were identified for the identification of both species and the conditions for their use in PCR were optimised. The specificity of the designed primers was checked by comparison with one population of P. punctata and populations of 14 other Heterodera species, nine populations of H. avenae and 10 populations of H. filipjevi originating from different countries. To test the sensitivity, the PCR was run with DNA extracted from five second-stage juveniles (J2) of H. avenae or five J2 of H. filipjevi mixed with DNA extracted from varying numbers of J2 of H. latipons. It was possible to detect as few as five J2 of H. avenae or H. filipjevi among 100 J2 of H. latipons. The two primers sets allow the detection of H. avenae and H. filipjevi where they occur in mixed populations with other Heterodera spp.     

Effect of treatment with a cationic antiviral compound on acute infection with bovine viral diarrhea virus

Bovine viral diarrhea virus (BVDV) is a widespread bovine pathogen capable of causing disease affecting multiple body systems. Previous studies have shown 2-(2-benzimidazolyl)-5-[4-(2-imidazolino)phenyl]furan dihydrochloride (DB772) effectively prevents BVDV infection in cell culture. The aim of this project was to assess the efficacy of DB772 for the prevention of acute BVDV infection. Four calves seronegative to BVDV were treated with DB772 and another 4 calves were treated with diluent only on the same dosing schedule. Each calf was subsequently challenged intranasally with BVDV. Virus was isolated consistently from untreated calves on days 4 to 8, while treated calves remained negative by virus isolation during this period. Azotemia was exhibited by all treated calves on day 4 resulting in the euthanasia of 1 calf on day 10 and the death of another on day 13. Virus was isolated from the 2 remaining treated calves on day 14 or 21. On day 21, both remaining treated calves and all 4 untreated calves had anti-BVDV antibody titers > 1:2048. This pilot study indicates that DB772 temporarily prevented acute disease due to BVDV, but carries a significant concern of renal toxicity.     

Genetic diversity of taro (Colocasia esculenta (L.) Schott) in Vanuatu (Oceania): an appraisal of the distribution of allelic diversity (DAD) with SSR markers

In Vanuatu, an oceanic archipelago located in south-west Pacific, taro (Colocasia esculenta (L.) Schott) is one of the staple crops. An eco-geographical survey of its genetic resources was conducted in ten villages, each located on a different island. A sample of 344 landraces referred as the National Sample (NS) was collected. Its genetic diversity was assessed using nine microsatellites markers and then was compared with an International Core Sample (ICS) that was previously distributed in the ten villages of the study in order to test the geographical distribution of allelic diversity as an effective mean for the on-farm conservation of root crops. The ICS was composed of 41 accessions, including 23 originating from South-East Asia. The molecular dataset revealed in the NS (1) 324 distinct multilocus genotypes, (2) six genetic clusters mainly differentiated by rare alleles, (3) a geographical structure of the genetic resources of taro based, within each village, on the dominance of one or two of these clusters rather that their exclusivity, and (4) an analogy between the patterns of dominant clusters between villages and the past and present social networks. In addition, accessions from the ICS revealed 52 new alleles. Based on these findings, we formulate hypotheses regarding the processes involved in the genetic diversification of taro in Vanuatu. We also discuss the use of this set of microsatellite markers along with the molecular dataset obtained from this study as effective tools to monitor the diversity and evolution of taro in the future.     

Effect of lead pollution on soil microbiological index under spinach (Spinacia oleracea L.) cultivation

Purpose

Lead (Pb) pollution is appearing as an alarming threat nowadays in both developed and developing countries. Excessive Pb concentrations in agricultural soils result in minimizing the microbiological activities which leads to the decrease in crop production. A pot experiment was conducted with the purpose to examine the deleterious effect of Pb on microbiological index under spinach cultivation.

Materials and methods

Pb was added to 5 kg soil in each pot (with 6 seeds/pot) using Pb(NO₃)₂ at the rate of 0, 150, 300, 450, and 600 mg kg^?1 with three replications in completely randomized design. All soil microbial, enzymatic, and chemical properties and plant growth parameters and nutrient uptake were measured by standard methods.

Results and discussion

Both soil and plant measured parameters decreased after the addition of Pb (150, 300, 450, and 600 mg Pb kg^?1 soil) treatments with the passage of time (from 15 to 60 days) compared with control (CK). However, high Pb levels had more suppressive effect, therefore, highest Pb level (600 mg Pb kg^?1 soil) significantly (P?<?0.05) decreased the microbial biomass carbon (5.59-fold); microbial biomass nitrogen (N; 11.71-fold); microbial biomass phosphorus (P; 25.1-fold); dehydrogenase (4.02-fold); phosphatase (9.40-fold); urease (9.26-fold); pH (1.40-fold); spinach shoot (2.17-fold) and root (2.54-fold) length; shoot (2.36-fold) and root (2.69-fold) fresh weight; shoot (3.90-fold) and root (3.50-fold) dry weight; chlorophyll content (5.60-fold); carotenoid content (4.29-fold); plant macronutrients uptake, i.e., N (4.38- and 2.97-fold), P (3.88- and 6.58-fold), K (3.88- and 4.6-fold), Ca (6.60- and 6.70-fold), and Mg (5.57- and 4.45-fold); and plant micronutrient uptake, i.e., Zn (2.39- and 3.05-fold), Cu (3.70- and 2.62-fold), Fe (4.13- and 3.23-fold), and Mn (4.17- and 4.09-fold) in spinach shoot and root, respectively. Conversely, highest Pb level, i.e., 600 mg Pb kg^?1 soil significantly (P?<?0.05) increased the biomass carbon (C)/nitrogen (N) (4.69-fold) and C/P (6.01-fold) ratios, soil extractable Pb (5.87-fold), and Pb uptake in spinach shoot (3.58-fold) and root (4.38-fold), respectively, at the end of the experiment, i.e., day 60.

Conclusions

Pb contamination significantly decreased the soil microbial and enzymatic activities, pH, spinach plant growth, and nutrients uptake in all the samples spiked with Pb. The degree of the influence increased with the increased Pb concentrations and incubation time, showing that Pb threshold is strongly associated with the extent of Pb concentration and time to accumulate. The soil microbial biomass, enzymatic activities, pH, and spinach physiological indices, could be used as a sensitive indicators to reflect environmental stress in soil ecosystems.