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Open access

Robert N. Rosenfield

Abstract

The demographic responses to severe weather by toplevel predators, including birds of prey, are underreported and/or unknown. Severe storms are predicted by climate change models to increase globally and in frequency into the 22nd century. In April 2018, a population of breeding Cooper’s hawks (Accipiter cooperii) in central Wisconsin, USA, experienced three days of heavy snowfall in the most severe storm, in preincubationstage, for 39 years (1980–2018). Here I report select demographic outcomes of this nesting population following this intense weather. The median hatching date of 10 June in 2018 was the sixth latest such metric in those 39 years (and the latest in 22 years since 1996) for this population, which has advanced its breeding schedule about 1.3 days/decade due to climate change or warming. Survival of a total of 16 color-marked breeding adults, 15 males and 1 female, observed pre-storm in the nesting areas, was 100% up through the late nestling stage in the same nesting areas where these birds were initially detected in 2018. Average clutch size (4.4 eggs/nest) and average brood size (4.0 young/ nest) were similar to the overall average annual metrics of these demographics for this population in the earlier 38 study years. Nest success, whereby 95% of 21 nests with eggs produced advanced-aged young, was higher in 2018 than the overall average of 77% nest success rate during the earlier years. The later timing of hatching in 2018, likely due to the severe spring snowstorm, appeared to have no deleterious effects either on survival of the breeding adults or on the reproductive output of this healthy study population. Tree-canopy prey may have served as important alternative food for this typically ground-foraging raptor in 2018.

Open access

Ismail Mohamed Helal

Abstract

This study aimed at investigating the antiviral activities of biocides made of formulated essential oils. These were derived from five plant species: fennel, oregano, peppermint, thyme and ginger. The potencies of these preparations were tested against local infection with the Tobacco necrosis virus (TNV) on common bean (Phaseolus vulgaris L.) and against systemic infection with the Cucumber mosaic virus (CMV) on cucumber (Cucumis sativus L.). After the determination of the most effective concentration, the formulated biocides were tested in protective and curative manners (before and after virus inoculation) against the growth of plants. The obtained results showed that the peppermint-derived biocide had the greatest effect on reducing the infectivity of the TNV virus (100% growth inhibition at 4000 ppm), whereas the biocide from thyme was the most effective against the infectivity of the CMV virus, as it induced a complete growth inhibition at 3000 ppm. The results of the protective and curative experiments revealed that the formulated biocides exerted high protection and curative effects against the two viruses. The observations revealed that the biocides were able to enhance plant defences against viral infection, as indicated by the increased levels of total chlorophyll, protein and phenols. Moreover, the levels of the oxidative stress markers including peroxidase (POD), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) were improved compared to the control settings. In conclusion, the formulated biocides progressively present a favourable alternative to chemically synthesized pesticides in crop protection.

Open access

Anam Moosa, Shahbaz Talib Sahi, Sajid Aleem Khan and Aman Ullah Malik

Abstract

The ability of salicylic acid and jasmonic acid to suppress post-harvest infection with green mould Penicillium digitatum and blue mould P. italicum on three citrus species Citrus reticulata ‘Kinnow’, C. limon ‘Meyer Lemon’, and C. limetta ‘Mosambi’ was evaluated in a dose-response study. Salicylic acid (SA) and jasmonic acid (JA) were applied to the fruits as a post-harvest dip treatment followed by wound inoculation with the pathogens. Both resistance inducers caused a significantly lower disease severity compared with the infected but non-treated control, whereas disease incidence was not significantly lower than in the control. The efficacy of both SA and JA in reducing disease severity was concentration-dependent; the use of higher concentrations resulted in a greater degree of suppression. All the Citrus species tested in this study showed different responses in terms of disease development. C. limon ‘Meyer Lemon’ showed the highest disease development, and C. limetta ‘Mosambi’ the lowest. To get an insight into the mechanisms underlying the increase in resistance, the activity of defence-related enzymes – peroxidase (POD) and polyphenol oxidase (PPO) – was recorded in SA- and JA-treated fruit peelings. The activity of both enzymes was directly proportional to the concentration of the SA and JA applications. The highest activity of PPO and POD was observed in C. reticulata ‘Kinnow’ and the lowest in C. limon ‘Meyer Lemon’ fruits. This study is the first to document an increase in the activity of PPO and POD in SA- and JA-treated Citrus species in the presence of blue mould and green mould pathogens.

Open access

Tomoki Hattori, Yang Chen, Shinichi Enoki, Daisuke Igarashi and Shunji Suzuki

Abstract

Berry skin colour is a crucial determinant of red/black grape berry quality. We investigated the effects of combination treatments with amino acids and a low concentration of ABA on anthocyanin accumulation in grapes. Among the amino acids tested, isoleucine and phenylalanine resulted in high anthocyanin contents in grape cell cultures. The combination treatments with isoleucine or phenylalanine, and a low concentration of ABA enhanced anthocyanin accumulation in grape cells and detached grape berries. The combination treatment with isoleucine, but not with phenylalanine, and ABA upregulated MybA1 expression. Field-grown grapevines received combination treatments with isoleucine or phenylalanine, and ABA in two growing seasons. In the 2015 growing season, the combination treatments with isoleucine or phenylalanine, and a low concentration of ABA accelerated anthocyanin accumulation in grape berry skins of field-grown grapevines on days 10 and 31 post treatment. The effects on anthocyanin accumulation became negligible at harvest. The effect of the combination treatment with phenylalanine and a low concentration of ABA on anthocyanin accumulation was masked in the 2017 growing season due to the unexpected stimulation of anthocyanin accumulation by the low concentration of ABA, although the combination treatment accelerated anthocyanin accumulation on days 3 and 10 post treatment. Taken together, the results suggested that exogenous isoleucine and phenylalanine interacted with ABA-mediated anthocyanin accumulation in grape berry skins of field-grown grapevines when the activity of ABA used to treat the grapevines was inadequate.

Open access

Larona Keabetswe, Guang Cheng Shao, Jintao Cui, Jia Lu and Tebogo Stimela

Abstract

Quality of fresh produce is the most critical issue in the economics of a vegetable enterprise. In order to investigate the effect of biochar amendment and deficit irrigation on tomato fruit quality, experimental research was conducted under a rain shelter in southern China during the 2017 and 2018 growing seasons. The experiment consisted of five treatments. Crops were irrigated to 100% of field water capacity at all growth stages as treatments T1 and T2. The other treatments received 30% less irrigation water than T2 when its soil water content reached 70% of field capacity, and were designated as treatments T3, T4 and T5, applied at the vegetative (stage I), flowering and fruit development (stage II), and fruit ripening (stage III) stages, respectively. Treatment T1 included no biochar, while the other treatments included 10% biochar by weight. The results showed that the total soluble solids (TSS) content, sugar-to-acid ratio (SAR), vitamin C (VC) content, and colour index (CI) increased in the deficit irrigation treatments depending on the phenological stage, the fruit ripening stage in particular. Meanwhile, single fruit weight was significantly (p > 0.05) reduced by water deficit at stages II and III, subsequently affecting the total fruit yield. Biochar improved soil moisture conservation and had a positive effect on fruit quality as evidenced by better single quality attributes (p > 0.05) of T2 over T1. The GRA and TOPSIS appraisal methods were used to conduct the comprehensive quality analysis. Eventually, treatment T5 ranked the best in both seasons, and this was also confirmed by the combinational evaluation method.

Open access

A. Tripathi, L. Wangchu and A. K. Trivedi

Summary

This work investigated the relationship of host size, seasons, and water quality parameters with the prevalence and intensity of Cornudiscoides agarwali on Mystus bleekeri collected from the Dikrong River in Arunachal Pradesh, India from February 2016 to January 2017. A total of 2760 specimens of C. agarwali were recovered from 114 individuals of M. bleekeri. The levels of mean intensity, but not the prevalence, of infection of C. agarwali were positively correlated with fish host size, peaking in the largest size class (45.20 ± 5.69 parasites/fish). The prevalence values had a statistically significant seasonal trend, reaching highest (100 %) during the pre-monsoon season, followed by 91.8% during the post-monsoon period and 87.5 % during the monsoon season. The levels of mean intensity of infection were also dependent on the seasons, reaching significantly higher levels during the pre-monsoon season (42.75 ± 4.18 parasites/fish). All water quality parameters measured were within the safety value recommended for freshwater aquaculture. Cornudiscoides agarwali maintained its prevalence above 87.5 % throughout the annual cycle, which means it was able to reproduce year-round in a non-polluted river. This could be an indication of monogenoidean community and population dynamics thriving best under optimum water quality parameters. Also, this article draws the attention of parasitologists and ichthyologists to a taxonomic problem of the misidentification of Mystus spp., and therefore, possibly of their parasitic monogenoids.

Open access

S. Sadet Canakoglu, S. Simsek, I. Balkaya and S. Gunyakti Kilinc

Summary

Fasciolosis caused by Fasciola hepatica is a common parasitic disease of livestock especially sheep and cattle. In this study molecular characterization of β-tubulin isotype 3 gene in Fasciola hepatica isolates from cattle and sheep in Turkey was carried out. For this purpose a total of 80 adult Fasciola hepatica isolates were collected from 20 sheep and 20 cattle in Kayseri and Erzurum provinces. PCR-RFLP was performed on β-tubulin isotype 3 gene and MboII revealed two fragments of approximately 350 bp and 390 bp, whereas HphI enzyme yielded 210, 340 and 540 bp bands, HindII yielded 380 and 450 bp bands in all samples. A total of 80 isolates were tested by SSCP and all of them presented the same band profiles. Six samples (4 sheep and 2 cattle) were randomly selected and DNA sequence of a 935 bp coding fragment of β-tubulin isotype 3 was performed. Sheep samples were more polymorphic than the cattle. This β-tubulin isotype 3 gene polymorphism of F.hepatica isolates from sheep and cattle of two distinct geographical areas of Turkey have been investigated for the first time.

Open access

R. K. Schuster

Summary

During a survey on tapeworm larval stages in Artemia franciscana from an artificial pond in Dubai, United Arab Emirates, a high prevalence of Eurycestus avoceti-like cysticercoids was established. Adult male and female crustaceans showed a prevalence of 61.9 and 62.7 %, respectively. The intensity ranged from one to four and one to three cyst, respectively. Out of 215 examined cysticercoids, 207 specimens had morphological features matching with E. avoceti. The flaky structure of the surrounding capsule, the elongated shape of the cysticercoid and the larger number of hooklets on the suckers suggest that the eight further larval cestodes belonged to another species of the genus Eurycestus.

Open access

J. S. Dar, B. A. Ganai, R. A. Shahardar and U. R. Zargar

Summary

The control of the digenetic trematode Fasciola gigantica has been the major challenge in both cattle and small ruminants as there is a paucity of an effective and commercial vaccine. Thus, the accurate identification and prepatent diagnosis of F. gigantica is an essential prerequisite for its successful prevention and control. In the present study, the morphologically identified specimens isolated from the liver and bile ducts of sheep (Ovis aries) were validated through molecular data. The sequence analysis of ITS-2 of our isolates showed high degree of similarity with F. gigantica and F. hepatica using BLAST function of NCBI. The phylogenetic analysis of our isolates showed a close relationship with previously described F. gigantica and F. hepatica isolates from different countries. The antigenic profile of somatic and E/S antigens of F. gigantica were revealed by SDS–PAGE and immunoblotting using sera from sheep naturally infected with F. gigantica. By SDS-PAGE, 20 distinct bands were revealed from crude somatic fraction. Immunoblotting analysis of these proteins with positive sera exhibited 8 sero-reactive bands ranging from 14 to 97 kDa. Among these 38 and 44 kDa bands were quite specific with high diagnostic specificity and sensitivity. The E/S fraction comprised 7 distinct bands, as revealed by SDS-PAGE analysis. Immunoblotting analysis of these proteins with positive sera exhibited 6 antigenic bands ranging from 23 – 54 kDa. Among these 27 and 33 kDa were found to be quite specific with high diagnostic specificity and sensitivity. The present study concludes that the protein bands of 38 and 44 kDa in somatic fraction and 27 and 33 kDa in E/S fraction can be used for the immunodiagnostic purpose for this economically important parasite, which may also entice further studies regarding their vaccine potential.

Open access

A. Güven and T. Öztürk

Summary

The metazoan parasites were investigated of two flatfish the common sole, Solea solea (n:140) and the scaldfish, Arnoglossus laterna (n: 22) in the Sinop coast of Black Sea from June 2015 to June 2017. A total of 15 metazoan parasite species belonging to Digenea (6), Cestoda (3), Acanthocephala (1), Nematoda (4) and Isopoda (1) taxonomic groups were identified. Solea solea was found to be infected by Condylocotyla pilodora, Proctoeces maculatus, Opecoelidae gen. sp., Metadena sp., Stephanostomum sp., Progrillotia sp., Capillaria gracilis, Cucullanus campanae, Solearhynchus rhytidotes and Nerocila orbignyi. Arnoglossus laterna was found to be infected by Lecithochirium musculus and Grillotia erinaceus. Scolex pleuronectis, Hysterothylacium aduncum and Dichelyne minutus were determined in both flatfish. Infection prevalence and mean intensity values were re- corded for each parasite species. Infection values for each parasite species in relation to season and fish size were also determined and compared as comparatively. This study is the first one assessing the metazoan parasites both of S. solea and A. laterna collected from the Turkish coast of Black Sea. While Condylocotyle pilodora and Capillaria gracilis are new parasite records for S. solea, Grillotia erinecaus is new parasite record for A. laterna. Moreover, this paper is the first report on occurrence of Opecoelidae gen. sp., Metadena and Stephanostomum genera in S. solea.