The innate immune response against Brucella in humans

Pathogens have developed different strategies to survive and multiply within their host. Among them is the ability to control phagocyte apoptosis while another is to affect the expression of cytokines which is necessary for a normal protective function of the immune response. To establish themselves and cause chronic disease in humans and animals, Brucella spp. invade and proliferate within monocytic phagocytes. We have established that in humans, Brucella suis impairs the apoptosis of monocytes and macrophages, thus preventing its host cell elimination. In mice, which are not naturally colonized by the bacteria, Brucella infection results in Type1 (Th1) cellular immune response which promotes a clearance of the bacterial organism. The development of this response is under the control of major cytokines like TNF-alpha, IFN-gamma and IL-12 produced at the onset of infection. We have observed that in humans, B. suis-infected macrophages which produce IL-1, IL-6, IL-10 and several chemokines including IL-8, do not secrete TNF-alpha. By constructing null mutants, we demonstrated that this inhibition involves the outer membrane protein Omp25 of Brucella, however the mechanism regulating the inhibition has not yet been clearly defined. It is likely that the Omp25-induced effect on TNF-alpha production assists bacterial evasion of antimicrobial defences at different levels. Firstly, by preventing the autocrine activation of macrophages thus inhibiting innate immunity and secondly by impairing the production of IL-12 and the development of a Th1 type specific immunity. In addition to the central role of the macrophage in Brucella infection, others cells of the innate immune response are recruited and influenced by the interactions between bacteria and host. For instance, human Vgamma9Vdelta2 T-cells play an important role in the early response to infection with intracellular pathogens. Evidence has been presented that their number dramatically increased in the peripheral blood of patients with acute brucellosis. We have shown that human Vgamma9Vdelta2 T-cells can be specifically activated by non-peptidic low molecular weight compound(s) from B. suis lysate or by soluble factors produced by B. suis-infected macrophages. Under these conditions, they produce TNF-alpha and IFN-gamma and reduce the bacterial multiplication inside infected autologous macrophages. This impairment of B. suis multiplication is due to both soluble factors released from activated gammadeltaT-cells (including TNF-alpha and IFN-gamma) and to a contact-dependent cytotoxicity directed against the infected cells. The interactions between the bacteria and these cells can counteract the intramacrophagic development of the bacteria and finally influence the further development of the host defense. We hypothesize that the chronicity or the elimination of the infection will depend on the balance between contradictory effects induced by the bacteria which favor either the host or the pathogen. Moreover, the interrelationship between the different cells must be taken into account in the analysis of the virulence of the bacteria and in the development of in vitro models of human macrophage infection.     

Insecticidal activity of N-arylalkylbenzhydrolpiperidines

Benzhydrolpiperidine (BZP) insecticides represent a novel class of chemistry. Their specificity and efficacy as well as their low mammalian toxicity give them excellent potential for commercialization. Several N-arylalkylbenzhydrolpiperidines were tested for activity against a variety of insects in the laboratory and greenhouse. These tests were used to select compounds for field trials and determine rates of application for field tests. The BZP compounds have good activity against Lepidoptera, with modest Coleoptera activity. They are toxic by oral administration and have about 100-fold lower activity by topical exposure. A methyl carbamate BZP, F4265, was the most active compound, with LC50 values of 6 mg litre(-1) or less for most Lepidopteran species tested. F4265 was active in a variety of field trials at 112-224gAI ha(-1). Whole-plant testing methods conducted in the greenhouse were effective in determining field test rates.     

Prospects for strain improvement in entomopathogenic fungi

The deployment of entomopathogenic fungi for the control of insect pests offers an environmentally-acceptable strategy. Major obstacles to their application include variability in effectiveness due to uncontrolled environmental parameters (temperature, humidity) and development of suitable formulation techniques. Strains differ considerably in genetic ability to cause mortality and to spread within populations. Pathogenicity is the result of the interaction of numerous individual traits determining germination and penetration, followed by successful growth within the target host, which is a prerequisite for induction of mortality. No effective singlegene determined toxin has been reported for entomopathogenic fungi, but the application of gene cloning techniques for specific proteases is a likely future development. Genetic manipulation techniques, designed to recombine complex traits associated with pathogenicity via the parasexual cycle, are described here in relation to successful steps achieved in strain improvement programmes which involve: (a) Verticillium lecanii (Zimm.) Viegas against the glasshouse whitefly: Trialeurodes vaporariorum and the aphid Macrosiphoniella sanborni; (b) Metarhizium anisopliae (Metsch.) Sorokin against the rice brown planthopper Nilaparvata lugens.     

Isolation of Amaranth Starch by Diluted Alkaline-Protease Treatment

Starch was isolated from Amaranthus cruentus seeds by different alkaline treatments and combinations of low alkaline steeping and protease treatments. For low alkaline-protease treatments, amaranth seeds were steeped in a NaOH solution (0.05%, pH 12) for 22 hr to loosen the protein matrix and ground. The pH of the ground slurry was adjusted to 7.5 and subjected to a protease (from Aspergillus sojae) treatment. The slurry was incubated with 1 or 0.5% of the protease (based on total amount of seeds) for 2 hr at 37°C and 50 rpm. The starch was then isolated by screening and centrifugation. This method produced starch with a low protein content (≤0.2%) and a high recovery (≈80%). Amaranth starch isolated by alkaline treatments were also studied by using various concentrations of NaOH steeping solutions and with or without alkaline solution during grinding and washing. The properties of amaranth starch isolated by alkaline and low alkaline-protease treatments were analyzed and compared. The properties of the amaranth starch were also compared with those of normal and waxy maize starches.     

Vertebral fusions in farmed Chinook salmon (Oncorhynchus tshawytscha) in New Zealand

Vertebral fusions are an established economic concern in farmed Atlantic salmon, but have not been studied in detail in farmed Chinook salmon. Two radiographic studies of vertebral fusions were performed in farmed Chinook salmon. Sixteen of 1,301 (1.2%) smolt and 201 of 2,636 (7.6%) harvest fish had fusions. There were no significant differences in the number of fused vertebrae/fusion in smolt compared with harvest fish. Secondly, tagged fish were repeatedly radiographed to determine the progression of the fusions. Nineteen (4.4%), 23 (5.3%) and 39 (9.0%) fish had fusions as smolt, after 129 days in sea water, and at harvest, respectively. There were no significant differences in the average number of vertebra/fusion between the three time points. Of the fusions that were observed in smolt, additional vertebra did not become fused in 81% of the lesions. Within the rare fusions that did progress due to the involvement of adjacent vertebra, an average of 1.6 vertebrae were added per year. Fish with fusions were significantly lighter than non‐affected fish at harvest. Fusions are common in farmed Chinook salmon; however, they are typically stable after development. As fish with fusions were lighter at harvest, reducing fusions may have an economic benefit.     

Influence of water management,photoperiod and aeration on growth,survival, and early spat settlement of the hatchery-reared green mussel,Perna viridis

In an attempt to induce early spat settlement and improve mussel seed production, this study aims to determine the influence of water management, photoperiod, and aeration, on the growth, survival and settlement of green mussel (Perna viridis). Water in the pediveliger rearing tanks was changed every day, every 3 days and every 5 days for the water-management experiment. Pediveligers were exposed in 24L:0D h (light: dark), 12L:12D h and 0L:24D h conditions for the photoperiod experiment. Three aeration intensities were also tested—mild (10 L h−1), moderate (20 L h−1), and strong (30 L h−1). This study demonstrated that changing water every 3 days was effective in maintaining the rearing water quality and improving the growth and survival of P. viridis larvae. Highest growth and survival rates were observed in P. viridis spats grown in 0L:24D h photoperiod. There was no significant difference in the settlement rate of larvae exposed to different photoperiods. Mild aeration has shown to improve the growth of P. viridis larvae, but higher survival and settlement rates were attained in the strongly-aerated conditions. Therefore, when the larvae start to settle, it is recommended to expose them to darkness, change the water every 3 days and provide a strong aeration to be able to attain high survival and settlement rates, and bigger spats.     

The mitigation hierarchy for sharks: A risk‐based framework for reconciling trade‐offs between shark conservation and fisheries objectives

Sharks and their cartilaginous relatives are one of the world's most threatened species groups. The primary cause is overfishing in targeted and bycatch fisheries. Reductions in fishing mortality are needed to halt shark population declines. However, this requires complex fisheries management decisions, which often entail trade‐offs between conservation objectives and fisheries objectives. We propose the mitigation hierarchy (MH)—a step‐wise precautionary approach for minimizing the impacts of human activity on biodiversity—as a novel framework for supporting these management decisions. We outline a holistic conceptual model for risks to sharks in fisheries, which includes biophysical, operational and socioeconomic considerations. We then demonstrate how this model, in conjunction with the MH, can support risk‐based least cost shark conservation. Through providing examples from real‐world fishery management problems, we illustrate how the MH can be applied to a range of species, fisheries and contexts, and explore some of the opportunities and challenges hereto. Finally, we outline next steps for research and implementation. This is important in the context of increasing international regulation of shark fishing and trade, which must lead to reductions in shark mortality, while managing trade‐offs between conservation objectives and the socioeconomic value of fisheries.     

Early distribution of radioactive liposomes and scrapie infectivity in mouse tissues following administration by different routes

Mice were injected with ^99mtechnetium-labelled liposomes or with a standard homogenate of scrapie-affected brain. Four different routes of injection were used, intracerebral (i.c.), intravenous (i.v.), intraperitoneal (i.p.) and subcutaneous (s.c.). Blood and a range of other tissues were removed between 5 min and several hours after injection. The tissues included spleen and salivary gland in which appreciable agent replication (or at least accumulation) is known to occur and, liver where replication of scrapie agent does not occur.Within 30 min of injection by any of the four routes used, radioactivity, and infectivity were detected in tissues remote from the site of injection. The distribution of radioactivity in various tissues was similar to that of infectious scrapie agent, but in both cases it occurred much more rapidly after i.v. injection than after injection by the i.p. or s.c. route. It is suggested that the 1000-fold reduced efficiency of scrapie infection by the s.c. route, compared to the i.v. route, is related to the extensive localisation of inoculum at the site of injection. Despite the relatively high efficiency of infection of the i.v. route, much of the detectable agent is taken up by liver where the agent does not replicate. It is concluded that only a very small proportion of the agent injected i.v. (and presumably by other routes) is involved in establishing scrapie infection of mice.