Cryopreservation of Trichinella newborn larvae

A technique for the cryopreservation of Trichinella spiralis newborn larvae is described. A similar procedure for muscle-stage larvae was not successful.     

Glycosidases of marine organisms

This review discusses the catalytic properties, activity regulation, structure, and functions of O-glycoside hydrolases from marine organisms exemplified by endo-1→3-β-D-glucanases of marine invertebrates.     

Cryopreservation of the first-stage larvae of trichostrongylid nematode parasites

First stage (L1) larvae of Haemonchus contortus, Trichostrongylus colubriformis and Ostertagia circumcincta can be cryopreserved in the presence of DMSO using a two-step freezing protocol involving an initial period at −80°C prior to transfer to liquid nitrogen. Thawed L1 larvae continue development in vitro producing third stage (L3) larvae that are infective to sheep when dosed per os. Establishment rates for L3 larvae grown from thawed L1 larvae were 40 and 80% for H. contortus and T. colubriformis, respectively. There was no difference in survival or infectivity between benzimidazole (BZ)-susceptible and BZ-resistant H. contortus isolates and cryopreservation caused no shift in their BZ-resistance status as indicated in an in vitro larval development assay. Cryopreservation also had no effect on the sensitivity of these isolates to the avermectins or levamisole in vitro. High survival rates (60–70%), good levels of establishment and the stability of anthelmintic resistance status of isolates indicate that little if any selection occurs during the cryopreservation process. L1 larvae of all 3 species have been successfully recovered after 16 months storage in liquid nitrogen, cultured to the L3 stage and established in sheep.     

Arsenic in marine organisms

A review of the nature and accumulation of arsenic in marine organisms is presented. A study of the literature has revealed a lack of information about the mechanisms of uptake, molecular transformations, and biochemical associations of arsenic within organisms, and it remains unclear whether a few forms of arsenic are ubiquitous. The arsenic forms present in marine sediments and their role in the biogeochemical cycling of arsenic are also largely unknown.     

Cryopreservation of first-stage and infective third-stage larvae of Strongyloides stercoralis

Infective third-stage larvae of Strongyloides stercoralis were frozen over liquid nitrogen and remained infective to dogs when thawed. Successful cryopreservation depended on a 30-60-min incubation in a cryoprotectant (10% DMSO and 10% dextran) before freezing and thawing the frozen larvae into RPMI. First-stage larvae could also be frozen by this method. Thawed first-stage larvae remained viable and continued their development to third-stage larvae, which were shown to be infective to dogs.     

Cold adaptation in marine organisms

Animals from polar seas exhibit numerous so called resistance adaptations that serve to maintain homeostasis at low temperature and prevent lethal freezing injury. Specialization to temperatures at or below 0 degrees C is associated with an inability to survive at temperatures above 3-8 degrees C. Polar fish synthesize various types of glycoproteins or peptides to lower the freezing point of most extracellular fluid compartments in a non-colligative manner. Antifreeze production is seasonal in boreal species and is often initiated by environmental cues other than low temperature, particularly short day lengths. Most of the adaptations that enable intertidal invertebrates to survive freezing are associated with their ability to withstand ariel exposure. Unique adaptations for freezing avoidance include the synthesis of low molecular mass ice-nucleating proteins that control and induce extracellular ice-formation. Marine poikilotherms also exhibit a range of capacity adaptations that increase the rate of some physiological processes so as to partially compensate for the effects of low temperature. However, the rate of embryonic development in a diverse range of marine organisms shows no evidence of temperature compensation. This results in a significant lengthening of the time from fertilization to hatching in polar, relative to temperate, species. Some aspects of the physiology of polar marine species, such as low metabolic and slow growth rates, probably result from a combination of low temperature and other factors such as the highly seasonal nature of food supplies. Although neuromuscular function shows a partial capacity adaptation in Antarctic fish, maximum swimming speeds are lower than for temperate and tropical species, particularly for early stages in the life history.     

Steroid glycosides from marine organisms

Structures, taxonomic distribution and biological activities of steroid glycosides isolated from marine organisms over the last 8-10 years are reviewed. The bibliography includes 130 references.     

Photoprotective compounds from marine organisms

The substantial loss in the stratospheric ozone layer and consequent increase in solar ultraviolet radiation on the earth’s surface have augmented the interest in searching for natural photoprotective compounds in organisms of marine as well as freshwater ecosystems. A number of photoprotective compounds such as mycosporine-like amino acids (MAAs), scytonemin, carotenoids and several other UV-absorbing substances of unknown chemical structure have been identified from different organisms. MAAs form the most common class of UV-absorbing compounds known to occur widely in various marine organisms; however, several compounds having UV-screening properties still need to be identified. The synthesis of scytonemin, a predominant UV-A-photoprotective pigment, is exclusively reported in cyanobacteria. Carotenoids are important components of the photosynthetic apparatus that serve both light-harvesting and photoprotective functions, either by direct quenching of the singlet oxygen or other toxic reactive oxygen species or by dissipating the excess energy in the photosynthetic apparatus. The production of photoprotective compounds is affected by several environmental factors such as different wavelengths of UVR, desiccation, nutrients, salt concentration, light as well as dark period, and still there is controversy about the biosynthesis of various photoprotective compounds. Recent studies have focused on marine organisms as a source of natural bioactive molecules having a photoprotective role, their biosynthesis and commercial application. However, there is a need for extensive work to explore the photoprotective role of various UV-absorbing compounds from marine habitats so that a range of biotechnological and pharmaceutical applications can be found.     

Cryopreservation of marine thraustochytrids (Labyrinthulomycetes)

In this research, the viability of three marine thraustochytrid isolates (fungoid protists) (WSG05, W15 and WH3) were investigated after freezing in liquid nitrogen. Five cryopreservative combinations containing horse serum, glycerol and dimethylsulfide (Me₂SO) were used. The thraustochytrids were assessed directly after removal from liquid nitrogen and cell concentration measured for 10 days post-thawing. Results indicated that a combination of horse serum and Me₂SO were the most effective cryoprotectants for each of the strains tested. Glycerol was only successful in producing growth in one of the strains once thawed.The protocols developed and tested in this study may have further application for cryopreserving other isolates in this class.     

Antifungal and antiviral products of marine organisms

Marine organisms including bacteria, fungi, algae, sponges, echinoderms, mollusks, and cephalochordates produce a variety of products with antifungal activity including bacterial chitinases, lipopeptides, and lactones; fungal (-)-sclerotiorin and peptaibols, purpurides B and C, berkedrimane B and purpuride; algal gambieric acids A and B, phlorotannins; 3,5-dibromo-2-(3,5-dibromo-2-methoxyphenoxy)phenol, spongistatin 1, eurysterols A and B, nortetillapyrone, bromotyrosine alkaloids, bis-indole alkaloid, ageloxime B and (-)-ageloxime D, haliscosamine, hamigeran G, hippolachnin A from sponges; echinoderm triterpene glycosides and alkene sulfates; molluscan kahalalide F and a 1485-Da peptide with a sequence SRSELIVHQR; and cepalochordate chitotriosidase and a 5026.9-Da antifungal peptide. The antiviral compounds from marine organisms include bacterial polysaccharide and furan-2-yl acetate; fungal macrolide, purpurester A, purpurquinone B, isoindolone derivatives, alterporriol Q, tetrahydroaltersolanol C and asperterrestide A, algal diterpenes, xylogalactofucan, alginic acid, glycolipid sulfoquinovosyldiacylglycerol, sulfated polysaccharide p-KG03, meroditerpenoids, methyl ester derivative of vatomaric acid, lectins, polysaccharides, tannins, cnidarian zoanthoxanthin alkaloids, norditerpenoid and capilloquinol; crustacean antilipopolysaccharide factors, molluscan hemocyanin; echinoderm triterpenoid glycosides; tunicate didemnin B, tamandarins A and B and; tilapia hepcidin 1-5 (TH 1-5), seabream SauMx1, SauMx2, and SauMx3, and orange-spotted grouper β-defensin. Although the mechanisms of antifungal and antiviral activities of only some of the aforementioned compounds have been elucidated, the possibility to use those known to have distinctly different mechanisms, good bioavailability, and minimal toxicity in combination therapy remains to be investigated. It is also worthwhile to test the marine antimicrobials for possible synergism with existing drugs. The prospects of employing them in clinical practice are promising in view of the wealth of these compounds from marine organisms. The compounds may also be used in agriculture and the food industry.     

Cryopreservation of the unicellular marine alga, Nannochloropsis oculata

In microalgal culture collections, as in many biological resource centres, cryoconservation is the most attractive method for the long-term, secure storage of living material. Nannochloropsis oculata, a marine unicellular alga, is of interest in the field of biotechnology due to its high lipid content. Of various cryoprotectants tested for their toxicity and for their ability to prevent cryoinjury, glycerol (final concentration 1.1 M) was the most efficient. When glycerol-treated cultures were submitted to a strictly regulated cooling rate (-3 degrees C min(-1)), they attained the control culture density within 13 d after thawing.     

Cryopreservation of sperm from the marine shrimp Sicyonia ingentis

Sperm from a marine shrimp, Sicyonia ingentis, were frozen to -196 degrees C using a variety of cooling rates and cryoprotectants. A cooling rate of 1 degree C/min resulted in minimal cell breakage. Sperm samples were frozen in solutions of known membrane stabilizers--trehalose, sucrose, proline, and glycerol. These compounds were somewhat effective but a dramatic increase in sperm viability was seen when DMSO was present in the freezing medium. Sperm viability was assessed using the in vitro acrosome reaction technique of Griffin et al. (1987). The highest sperm survival (56%) was obtained with samples frozen at 1 degrees C/min in a 5% (v/v) DMSO solution. No decrease in viability was seen in sperm samples stored in liquid nitrogen (-196 degrees C) for 1 month.     

Molecular genetics and the management and conservation of marine organisms

Biochemical and molecular species identification techniques have a broad range of applications in the management and conservation of marine organisms. While species boundaries are not always clearly defined, phylogeneticists utilise autapomorphic characters to distinguish phylogenetic species. Genetic markers discriminate between marine taxa when traditional morphological distinctions are unclear. The applications of these techniques can be divided into four general categories. Firstly, compliance enforcement, which often depends on genetic identification techniques to enable officials to identify the species to which regulations pertain. Secondly, quality control applications, to allow for the testing of marine products to guard against fraudulent substitution with less valuable species, which is particularly pertinent since processing often obliterates identifiable features. Thirdly, a variety of applications to ecological and life-history studies and conservation management are reported. Here, the genetic identification techniques of species from cryptic life-cycle stages or of morphologically indistinct species are an indispensable tool for marine scientists, conservators and managers. Lastly, the application of genetic techniques for sourcing population origin is briefly discussed. The biochemical and molecular techniques applied to species identification all exploit phenotypic or genotypic polymorphisms that are sampled using either tertiary level protein based methods or primary level DNA based methods. In this review, examples of the applications along with the total protein, allozyme, serological, PCR and other DNA based methodologies are briefly described and some generalities with regard to their use are presented.     

Intact antigen uptake in intestinal epithelial cells of marine fish larvae

Endocytosis of bacteria by epithelial cells in the hindgut of 4- to 6-day-old cod ( Gadus morhua L. ) larvae and of 10- to 12-day-old herring ( Clupea harengus L. ) larvae was demonstrated by fluorescence microscopy and transmission electron microscopy. Fixed sheep erythrocytes and bacteria-sized latex particles were not ingested by these cells. By immunohistochemical methods intact bacterial antigens were observed in columnar epithelial cells in the foregut of 4-day-old yolk-sac larvae of cod. In these cells a preferential uptake of Vibrio fischeri and Vibrio salmonicida cells as compared to Flavobacterium sp. was found. The possible role of these findings in the establishment of an indigenous microflora, defence against pathogens or nutrient absorption in fish larvae is discussed.     

Adaptation capabilities of marine modular organisms

Marine modular organisms such as hydroids and coralsare plastic in their responses to continuouslychanging environments. Morphogenetic limitations areless important for modular animals and plants, thanfor unitary ones. Although each module variesrelatively little, modular organisms are characterizedby an extremely broad plasticity of shape. Sessilecolonial animals grow into a heterogenous environmentand so each modular organism has its own often uniqueshape. The mechanism of modular body plasticity andadaptation to the environment is based on cyclicalmorphogenesis through replication of modules.Plasticity of shape is achieved not only by colonialgrowth, but during unfavorable periods also by bodyreduction due to module reabsorbtion.     

On the origin of pristane in marine organisms

Phytol-U-(14)C was adsorbed on algae and ingested in this form by zooplanktonic copepods (two species of Calanus). The lipids of these animals were analyzed after 48 hr and found to contain radioactive pristane and radioactive phytanic acid. The conversion of phytol to pristane by the copepods is interpreted as a likely biological source of pristane in nature.     

Prospective of the cosmeceuticals derived from marine organisms

Cosmeceuticals, derived from the words ‘cosmetic and pharmaceutical’, have drug-like benefits and contain active ingredients such as vitamins, phytochemicals, enzymes, antioxidants, and essential oils. Cosmeceuticals have attracted increased attention because of their beneficial effects on human health. Bioactive substances derived from marine organisms have diverse functional roles as a secondary metabolite and these properties can be applied to the developments of novel pharmaceuticals and cosmeceuticals. Recently, extensive studies have been conducted on the general aspects of the chemical structures, physical and biochemical properties, and biotechnological applications of bioactive substances derived from marine organisms. In this review, we have discussed recent progresses in the biotechnological applications of bioactive substances from marine organisms as cosmeceuticals.     

Indicator organisms for estuarine and marine waters

Abstract The use of indicator organisms for estuarine and coastal waters has been reviewed. The natural flora of the environment must be considered in selecting an indicator organism, but, more importantly, recent work which shows a viable but non-recoverable stage of pathogens entering the marine environment demonstrates that the conventional detection of indicator microorganisms is misleading, if not inaccurate. Results suggest that the newly developed epifluorescent/immunofluorescent direct detection of pathogens in the environment may be the most reliable method for determining public health hazards in marine and estuarine waters.