Shell disease in crustaceans – just chitin recycling gone wrong? (original) (raw)
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Biodegradation of the chitin-protein complex in crustacean cuticle
1998
AbstractÐArthropod cuticles consist predominantly of chitin cross-linked with proteins. While there is some experimental evidence that this chitin-protein complex may resist decay, the chemical changes that occur during degradation have not been investigated in detail. The stomatopod crustacean Neogonodactylus oerstedii was decayed in the laboratory under anoxic conditions. A combination of pyrolysis-gas chromatography/mass spectrometry and FTIR revealed extensive chemical changes after just 2 weeks that resulted in a cuticle composition dominated by chitin. Quantitative analysis of amino acids (by HPLC) and chitin showed that the major loss of proteins and chitin occurred between weeks 1 and 2. After 8 weeks tyrosine, tryptophan and valine are the most prominent amino acid moieties, showing their resistance to degradation. The presence of cyclic ketones in the pyrolysates indicates that mucopolysaccharides or other bound non-chitinous carbohydrates are also resistant to decay. There is no evidence of structural degradation of chitin prior to 8 weeks when FTIR revealed a reduction in chitin-speci®c bands. The chemical changes are paralleled by structural changes in the cuticle, which becomes an increasingly open structure consisting of loose chitinous ®bres. The rapid rate of decay in the experiments suggests that where chitin and protein are preserved in fossil cuticles degradation must have been inhibited. #
Chitinolytic bacteria are believed to be the primary aetiological agents of shell disease syndrome in marine crustaceans. The disease principally results from the breakdown of their chitinous exoskeletons by the shell disease pathogens, but pathogenicity may also manifest internally should a breach of the carapace occur. The current study looks at the pathogenicity of a number of bacteria (predominantly from the genus Vibrio) isolated from the edible crab, Cancer pagurus. All chitinase-producing bacteria investigated were capable of growth in a minimal medium consisting of chitin powder from crab shells, but differed in their speed of growth and nature of chitinolytic activity, suggesting that they have different roles within the lesion community. Two isolates (designated I4 and I7) were chosen for studies on internal pathogenicity, which included the effect of the pathogen on crab tissues, the ability of the host to remove the bacteria from circulation and the antibacterial activity of crab blood. Initially, I4 was rapidly removed from circulation, but began to reappear in the blood after 24 h. By 100 h, 100 % of crabs were moribund. The septicaemic effects of the isolate were reflected in the low levels of its killing by blood-cell lysate and serum. By contrast, I7 was only slowly removed from circulation and caused the rapid mortality of all crabs in T 3 h. A large decline in the number of circulating blood cells following injection of I7 was mirrored by an accumulation of these cells in the gills. Initial experiments suggest that the death of the crabs following injection with I7 may be caused by toxic extracellular bacterial products that exert their effects on the blood cells and nervous system of the crabs.
Degradation of barnacle nauplii: implications to chitin regulation in the marine environment
Biologia, 2013
The exoskeleton of most invertebrate larval forms is made of chitin, which is a linear polysaccharide of β (1→4)-linked N-acetylglucosamine (GlcNAc) residues. These larval forms offer extensive body surface for bacterial attachment and colonization. In nature, degradation of chitin involves a cascade of processes brought about by chitinases produced by specific bacteria in the marine environment. Microbial decomposition of larval carcasses serves as an alternate mechanism for nutrient regeneration, elemental cycling and microbial production. The present study was undertaken to assess the influence of chitinase enzyme on the degradation of the nauplii of barnacle, Balanus amphitrite. The survival and abundance of bacteria during the degradation process under different experimental conditions was monitored. To the best of our knowledge, no such study is conducted to understand the degradation of larval exoskeleton using chitinase and its influence on bacteria. An increase in the chiti...
Extraction and Purification of Chitin and Chitosan Production from Crustaceans
International Journal of Biological and Environmental Investigations
The aim of this study was to report the yield of extraction, as well as the physicochemical and cell reinforcement properties of removed chitosan from Crustaceans. In this work, chitin and chitosan from Crustaceans were acquired by treatment with HCl and NaOH. It is obtained from the cell walls of certain growths, exoskeletons, and inner design of spineless creatures and exuviae of crustaceans. The purpose of the study was to report the yield of extraction, as well as the physicochemical and cell reinforcement properties of removed chitosan from Crustaceans Plastic is the most advantageous material man has at any point found because of its relative affordability, simplicity of assembling, adaptability, and impenetrability to water. Plastics are utilized from paper clasps to spaceships and dislodged materials like wood, metal, bones and horns, stone, calfskin, paper, and even ceramics in a large portion of their previous purposes. Be that as it may, plastic appeared to make an extreme impact. An answer can be accomplished by the utilization the Bioplastics. Bioplastics are very much like plastics, however, rather than non-sustainable oil as the source, it utilizes natural sources like plant sources (corn starch, soybean oil, hemp oil, and so forth) and microbial sources. They can be made by utilizing plant sugar transformation, maturation, and development. Dissimilar to petro plastics they are biodegradable when arranged appropriately subsequently decreasing waste creation and ecological contamination. The vital business wellsprings of chitin are shells of Crustaceans, for example, shrimps, crabs, lobsters, and krill that are provided in enormous amounts by shellfish handling enterprises.
Journal of Invertebrate Pathology, 2010
The present research reports the first description of Shell Disease Syndrome in European spiny lobsters Palinurus elephas (Fabricius 1787), which occurred in an experimental aquaculture facility in Sicily (Italy). Both bacterial characterization and histopathological examination of the exoskeleton at site of lesions was carried out. Infected specimens showed tail fan erosions, and in one case uropod ulceration and complete loss of periods. Identified species included: Listonella anguillarum 50.5%, Vibrio parahaemolyticus 27.5% and Vibrio alginolyticus 22%. Microscopic evaluation of lesions indicate the presence of inflammatory responses, which include melanization and pseudomembrane formation, similar to those described for other crustaceans affected by SDS.
Chitin Facilitated Mineralization in the Eastern Oyster
Frontiers in Marine Science
Chitin is often reported in molluscan shells, where it likely contributes to the mechanical strength of the biomineral. However, the role of this polysaccharide in relation to the process of shell formation is not well understood. We investigated the deposition of chitin during shell repair in the Eastern oyster, Crassostrea virginica, by inserting stainless steel and glass implants in a region of shell damage. This work documents the time course of deposition of both chitin fibrils and calcium carbonate layers. Chitin was detected by confocal laser scanning microscopy (CLSM) using a chitin-specific fluorescent probe that was produced from clones of a chitin-binding domain. The presence of fibrils was confirmed using electron microscopy of implants. The fibrils' dimensions were reduced after treatment with both acid and bleach, suggesting that chitin interacts with inorganic minerals and other organic components such as proteins and lipids as early as 5 h after shell damage. With CLSM, it was shown that chitin co-localized with the cell membrane, suggesting the importance of cells located on the implants in the process of fibril formation. Using observations from this study as well as those from the literature on chitin synthase production, we propose two cellular models for chitin deposition related to shell formation.
Sri Lanka Journal of Aquatic Sciences, 2017
Shell waste produced by the sea food industry is one of the most significant problems contributing for environmental and health hazards. The most frequent method employed for disposal of these waste is burning which is environmentally costly due to low burning capacity of shells. In such a scenario, conversion of shrimp shell waste to chitosan, a commercially valuable product with a myriad of uses, could serve as an effective mode of shell remediation. Chitosan was obtained from shellfish waste by deproteination, demineralization, discoloration and deacetylation processes. It was characterized using Fourier Transformed Infra-Red (FT-IR) spectroscopy. The physico-chemical parameters such as moisture content, ash content, solubility, N-content, water binding capacity (WBC), fat binding capacity (FBC) and degree of deacetylation (DD) were analysed to compare the extracted six chitosan samples from Penaeus monodon, Portunus pelagicus, Portunus sanguinolentus, Scylla serrata, Panulirus h...
Chitin Extraction from Crustacean Shells Using Biological Methods - A Review
Food Technology and Biotechnology
After cellulose, chitin is the most widespread biopolymer in nature. Chitin and its derivatives have great economic value because of their biological activities and their industrial and biomedical applications. It can be extracted from three sources, namely crustaceans, insects and microorganisms. However, the main commercial sources of chitin are shells of crustaceans such as shrimps, crabs, lobsters and krill that are supplied in large quantities by the shellfish processing industries. Extraction of chitin involves two steps, demineralisation and deproteinisation, which can be conducted by two methods, chemical or biological. The chemical method requires the use of acids and bases, while the biological method involves microorganisms. Although lactic acid bacteria are mainly applied, other microbial species including proteolytic bacteria have also been successfully implemented, as well as mixed cultures involving lactic acid-producing bacteria and proteolytic microorganisms. The pr...
Length-based variations in deposition of chitin in the exoskeleton of Penaeus monodon and P. indicus
Sri Lanka Journal of Aquatic Sciences, 2018
Shrimp waste produced at the processing factories is a burden to the environment. Nevertheless, it is a raw material for extraction of chitin which is with more commercial uses. In this study chitin was extracted from shrimp waste collected from three different length ranges (5-10cm, 10-15cm, 15-20cm) of Penaeus monodon and P. indicus from a local small-scale processing factory, to determine the most suitable length class of shrimps to obtain a higher chitin yield. Dried shrimp waste was preconditioned by soaking in acetic acid, demineralized by treating with HCl and deproteinized by treating with NaOH. Extracted chitin was odourless, and pinkish white and off-white in P. monodon in P. indicus respectively. Highest chitin yield was from the largest size range of both species, P. monodon (30.5%) and P. indicus (27.86%). Ash, moisture, fat and nitrogen of extracted chitin were 0.98%, 5.80% and 6.16 % in P. monodon and 0.98%, 5.72% and 6.22% in P. indicus of dry weight respectively, w...
Isolation and Characterization of Chitin from Shells of the Freshwater Crab Potamon Algeriense
Background: Chitin is the second most abundant bio-polysaccharide found in nature after cellulose. It is a polymer of β-1, 4-N-acetylglucosamine that occurs naturally in three polymorphic forms α, β, and γ-chitin. The main commercial sources of chitin are crab and shrimp shells which are the major waste products from the seafood industry. The main aim of the current work was to isolate chitin from a local variety of Millipede (Spirobolida), which is abundantly found in Western Ghat region of Karnataka during monsoon and post-monsoon seasons. Methods: The millipedes were collected during the monsoon season from Western Ghat region and washed with distilled water. The shells were extracted from Millipede by incinerating the sample to remove other organic matter. The chitin was extraction from the shell by demineralization and deproteinization. Results: Chitin was extracted and analyzed by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) studies. The yield of chitin was found to be 35.7%. This is a good yield percentage compared to that of the chitin obtained from conventional sources. Conclusions: The chitin thus obtained can be employed for preparing chitosan linked nanoparticles for various applications. Hence, our studies illustrate that Millipedes can also be used as a source for large-scale extraction of chitin.