Characterization and Inhibitor Studies of Chitinases from a Parasitic Blowfly (Lucilia cuprina), a Tick (Boophilus microplus), an Intestinal Nematode (Haemonchus contortus) and a Bean (Phaseolus vulgaris)

The molecular weight pattern and the stage-specific activities of chitinases from the blowfly Lucilia cuprina, the tick Boophilus microplus and the intestinal nematode Haemonchus contortus were examined. Chitinolytic enzymes could be detected in all parasite species tested, but the activity was different between the stages. Highest chitinolytic titers were found in blowfly pupae (83 kDa, 118 kDa), hatching larvae of ticks (58 kDa, 94 kDa) and nematode eggs (43 kDa). Leaves from ethylene-treated bean plants Phaseolus vulgaris expressed two basic Class I chitinases (Ia, Ib) of 34 kDa, differing in their amino acid sequences at residue 33 and 34 (Ia: glycine, proline; Ib: lysine, aspartic acid). Inhibitor studies with blowfly pupae revealed that allosamidin (IC₅₀=0·32 (±0·02) μM ) was by far the best inhibitor when compared with various amino sugar derivatives. This compound also inhibited chitinases from tick larvae (IC₅₀=0·69(±0·10) μM ) and nematode eggs (IC₅₀=0·048(±0·0045) μM ) specifically. Whereas Class Ia chitinase from bean leaves was inhibited only up to 18% by 10 μM allosamidin, it had an IC₅₀ of 1(±0·14) μM for the Ib type, which is the first plant chitinase described to be highly sensitive to allosamidin.     

Synthesis and Antifouling Activity Evaluation of Analogs of Bromosphaerol,a Brominated Diterpene Isolated from the Red Alga Sphaerococcus coronopifolius

Marine biofouling is an epibiotic biological process that affects almost any kind of submerged surface, causing globally significant economic problems mainly for the shipping industry and aquaculture companies, and its prevention so far has been associated with adverse environmental effects for non-target organisms. Previously, we have identified bromosphaerol (1), a brominated diterpene isolated from the red alga Sphaerococcus coronopifolius, as a promising agent with significant antifouling activity, exerting strong anti-settlement activity against larvae of Amphibalanus (Balanus) amphitrite and very low toxicity. The significant antifouling activity and low toxicity of bromosphaerol (1) motivated us to explore its chemistry, aiming to optimize its antifouling potential through the preparation of a number of analogs. Following different synthetic routes, we successfully synthesized 15 structural analogs (2–16) of bromosphaerol (1), decorated with different functional groups. The anti-settlement activity (EC₅₀) and the degree of toxicity (LC₅₀) of the bromosphaerol derivatives were evaluated using cyprids and nauplii of the cirriped crustacean A. amphitrite as a model organism. Derivatives 2, 4, and 6–16 showed diverse levels of antifouling activity. Among them, compounds 9 and 13 can be considered as well-performing antifoulants, exerting their activity through a non-toxic mechanism.     

Clostridium bifermentans and C. subterminale are associated with kiwifruit vine decline,known as moria,in Italy

Since 2012, a new pathogenic syndrome has frequently been observed in many areas of kiwifruit cultivation in Italy. The main symptoms include an initial withering of the leaves followed by a total and sudden collapse of plants, mainly occurring during summer. The withered leaves fall and the main and secondary feeder roots appear rotten, sometimes showing a reddish-brown discoloration. The disease, that affects both the green and yellow-fleshed cultivars, has been called kiwifruit vine decline and is locally known as moria. The syndrome has been found consistently associated with soil waterlogging, which frequently occurs either after the traditional agronomical practice of irrigating orchards through surface irrigation or after very heavy rainfall. So far, the role played by bacteria in this syndrome has not been investigated. In the present study, Clostridium spp. were isolated from both rotten roots and soils obtained from Italian kiwifruit orchards affected by the syndrome, indicating for the first time that anaerobic bacteria are able to cause damage to woody crops. C. bifermentans and C. subterminale incited symptoms in kiwifruit in both in vivo and in vitro pathogenicity tests. Soil waterlogging seems to potentially favour colonization of kiwifruit roots by anaerobic bacteria, probably because saturation of the soil can facilitate proliferation and persistence of these bacteria during long periods of the vegetative growth of the crop. The occurrence of anaerobic bacteria does not exclude the possibility that other microorganisms can play additional/synergic role(s) in causing the kiwifruit vine decline.     

水质对猪的重要性

即使是最有进取心的养猪生产者也会忽视水质对猪生产性能的影响。尽管水质检验表明猪场水质仍在可接受的范围内,但水管内积聚起的水藻、细     

Assessing spillover from marine protected areas and its drivers: A meta‐analytical approach

Overfishing may seriously impact fish populations and ecosystems. Marine protected areas (MPAs) are key tools for biodiversity conservation and fisheries management, yet the fisheries benefits remain debateable. Many MPAs include a fully protected area (FPA), restricting all activities, within a partially protected area (PPA) where potentially sustainable activities are permitted. An effective tool for biodiversity conservation, FPAs, can sustain local fisheries via spillover, that is the outward export of individuals from FPAs. Spillover refers to both: “ecological spillover”: outward net emigration of juveniles, subadults and/or adults from the FPA; and “fishery spillover”: the fraction of ecological spillover that directly benefits fishery yields and revenues through fishable biomass. Yet, how common is spillover remains controversial. We present a meta‐analysis of a unique global database covering 23 FPAs worldwide, using published literature and purposely collected field data, to assess the capacity of FPAs to export biomass and whether this response was mediated by specific FPA features (e.g. size, age) or species characteristics (e.g. mobility, economic value). Results show fish biomass and abundance outside FPAs was higher: (a) in locations close to FPA borders (<200 m) than further away (>200 m); (b) for species with a high commercial value; and (c) in the presence of PPA surrounding the FPA. Spillover was slightly higher in FPAs that were larger and older and for more mobile species. Based on the broadest data set compiled to date on marine species ecological spillover beyond FPAs' borders, our work highlights elements that could guide strategies to enhance local fishery management using MPAs.     

Toxicity of aqueous aluminium to the ectoparasitic monogenean Gyrodactylus salaris

Both laboratory and field experiments have demonstrated that aqueous aluminium can act as a paraciticide to the monogenean Gyrodactylus salaris Malmberg, 1957 infecting freshwater salmonids. However, the reproductive conditions of gyrodactylids surviving to cessation of an aluminium exposure is unknown. Therefore, Atlantic salmon (Salmo salar L.) parr infected with G. salaris was experimentally exposed to elevated concentrations of aqueous aluminium for more than 1 month. During this period, the infection increased the first week before it peaked and started to steadily decline approaching elimination. When almost all parasite specimens were eliminated, the water quality was adjusted to normal aluminium-poor freshwater. During the next 3 weeks, the surviving G. salaris were shown to clearly resume their reproduction. The experiment demonstrates the potential of the gyrodactylids to reproduce after cessation of an aluminium exposure. Thus, the as-yet unknown mechanism behind the toxic effects of aluminium on G. salaris survival and reproduction might to some extent be reversible. The present study gives further support for this metal as a parasiticide to G. salaris but demonstrates at the same time that in order to eliminate the parasites totally, the aluminium treatment must eradicate all G. salaris from the skin of the infected hosts. Furthermore, the potential development of resistance to aluminium should also be studied.