Alien Registration- Snieszko, Stanislas (Orono, Penobscot County)

https://digitalmaine.com/alien_docs/5761/thumbnail.jp

The scope of the crustacean immune system for disease control

The culture or wild capture of marine and freshwater shellfish, including crustaceans, is without doubt a key source of protein for a burgeoning world population. Historically the expansion of aquaculture has, however, been accompanied by the increased incidence of economically significant diseases, most notably of viral and bacterial origin. Since the late 1970s great progress has been made in our understanding of the generalized protostome innate immune system. Distinct pathways, pathogen receptor proteins and effector molecules have since been identified that are not ancestral or homologous to those of the deuterostomes, including vertebrates. Within the past decade progress has accelerated with the rapid characterisation of new classes of recognition proteins, immune effectors and regulatory pathways. This paper provides a broad overview of our current understanding of invertebrate immunology, taking the crustacean decapod immune system as its focus. Recent developments in the field are described briefly and their implications and potential considered. These advances offer fundamental new insights in our efforts to understand disease in cultured populations and also to develop knowledge of environmental effects on host/pathogen interactions within a fishery context. Of course, challenges do remain, including the lack of an immortal cell line and the limited publically-available genomic resources. These are considered in this review as priorities for future research effort. With the continued application of more insightful technologies, coupled with associated investment, it is expected that the speed at which some of these issues are resolved will accelerate

Variation in the molecular weight of Photobacterium damselae subsp. piscicida antigens when cultured under different conditions in vitro

The antigenicity of Photobacterium damselae (Ph. d.) subsp. piscicida, cultured in four different growth media [tryptone soya broth (TSB), glucose-rich medium (GRM), iron-depleted TSB (TSB + IR-), and iron-depleted GRM (GRM + IR-)] was compared by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis using sera obtained from sea bass (Dicentrarchus labrax) raised against live or heat-killed Ph. d. subsp. piscicida. The antigenic expression of Ph. d. subsp. piscicida was found to differ depending on the culture medium used. A significantly higher antibody response was obtained with iron-depleted bacteria by ELISA compared with non-iron depleted bacteria obtained from the sera of sea bass raised against live Ph. d. subsp. piscicida. The sera from sea bass raised against live bacteria showed a band at 22 kDa in bacteria cultured in TSB + IR- or GRM+ IR- when bacteria that had been freshly isolated from fish were used for the screening, while bands at 24 and 47 kDa were observed with bacteria cultured in TSB or GRM. When bacteria were passaged several times on tryptic soya agar prior to culturing in the four different media, only bands at 24 and 47 kDa were recognized, regardless of the medium used to culture the bacteria. It would appear that the molecular weight of Ph. d. subsp. piscicida antigens change in the presence of iron restriction, and sera from sea bass infected with live bacteria are able to detect epitopes on the antigens after this shift in molecular weight

AIP56: A Novel Bacterial Apoptogenic Toxin

Photobacterium damselae subsp. piscicida (Phdp) is a Gram-negative pathogen agent of an important fish septicemia. The key virulence factor of Phdp is the plasmid-encoded exotoxin AIP56, which is secreted by exponentially growing pathogenic strains. AIP56 has 520 amino acids including an N-terminal cleavable signal peptide of 23 amino acid residues, two cysteine residues and a zinc-binding region signature HEXXH that is typical of most zinc metallopeptidases. AIP56 induces in vitro and in vivo selective apoptosis of fish macrophages and neutrophils through a caspase-3 dependent mechanism that also involves caspase-8 and -9. In vivo, the AIP56-induced phagocyte apoptosis progresses to secondary necrosis with release of cytotoxic phagocyte molecules including neutrophil elastase. Fish injected with recombinant AIP56 die with a pathology similar to that seen in the natural infection

Passing the Panda Standard: A TAD Off the Mark?

Tilapia, a tropical freshwater fish native to Africa, is an increasingly important global food commodity. The World Wide Fund for Nature (WWF), a major environmental nongovernmental organization, has established stakeholder dialogues to formulate farm certification standards that promote ‘‘responsible’’ culture practices. As a preface to its ‘‘tilapia aquaculture dialogue,’’ the WWF for Nature commissioned a review of potential certification issues, later published as a peer-reviewed article. This article contends that both the review and the draft certification standards subsequently developed fail to adequately integrate critical factors governing the relative sustainability of tilapia production and thereby miss more significant issues related to resource-use efficiency and the appropriation of ecosystem space and services. This raises a distinct possibility that subsequent certification will promote intensive systems of tilapia production that are far less ecologically benign than existing widely practiced semiintensive alternatives. Given the likely future significance of this emergent standard, it is contended that a more holistic approach to certification is essential

Alien Registration- Snieszko, Julia J. (Orono, Penobscot County)

https://digitalmaine.com/alien_docs/5760/thumbnail.jp

BACTERIAL GILL DISEASE OF FRESHWATER FISHES

Bacterial gill disease (BGD) was first described by Davis (1926, 1927), who observed it in fry and fingerling brook trout (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri) in hatcheries in Vermont. The affected trout were kept in dirt-bottom ponds and were not crowded; , daily mortalities were very low. Mortalities rapidly increased when the water temperature increased and diminished when the temperature decreased. Examination of the diseased trout revealed clubbing of gill filaments. In microscopic examination of wet mounts of the filaments Davis found that the gill surface was covered with closely adhering strands of long, thin bacteria. He called the condition bacterial gill disease, but did not attempt to isolate or identify the bacteria

MYCOBACTERIOSIS (TUBERCULOSIS) OF FISHES

Mycobacteria are widely distributed in nature. They are abundant in the soil, on the surface of plants, on the skin of vertebrates, in human food (e.g., milk and butter), and in animal feeds. Most mycobacteria are saprophytic, but some species are highly pathogenic and cause diseases such as tuberculosis and leprosy in humans, and similar diseases in mammals, birds, reptiles, amphibians, and fishes. Mycobacteria that cause diseases of fishes differ considerably from those that cause diseases in humans and other mammals. Therefore, to avoid association between tuberculosis in mammals and mycobacterial infections in fishes, it is better to call the disease mycobacteriosis of fishes

COLUMNARIS DISEASE OF FISHES

Columnaris disease is a chronic to acute infection that affects salmonids and many species of warmwater fishes. The first description of the disease was given by Davis (1922) who named the disease and bacterium from the columnar arrangement of cells as seen in wet mounts. The bacterium causing columnaris disease was first isolated by Ordal and Rucker (1944). They identified the organism as belonging to the group known as slime bacteria or myxobacteria; because it produced fruiting bodies and microcysts, they named it Chondrococcus columnaris. Garnjobst (1945), who was unable to find fruiting bodies, renamed it Cytophaga columnaris. However, in the recently revised Bergey\u27s Manual of Determinative Bacteriology (Buchanan and Gibbons 1974) the columnaris organism and other fish pathogenic myxobacteria have been reclassified as flexibacteria. The forms of flexibacteria pathogenic to fish were recently reviewed by Bullock et al. (1971), McCarthy (1975), and Pacha and Ordal (1970)