美丽海绵提取物防污损作用

从美丽海绵分离提取了2-去氧-1-氢-1,2,4,三唑、环(脯氨酸-甘氨酸)、尿嘧啶、环(脯氨酸-丙氨酸)、6-氨基嘌呤、4-(1-苯乙基)苯酚、1-氢-1,2,4,三唑和胆甾-5-烯-3β,7α-二醇等8种化合物,并研究了其对网纹藤壶金星幼虫的影响,其中6-氨基嘌呤(7.1 μg/cm2)和4-(1-苯乙基)苯酚(5.9μg/cm2)对金星幼虫具有明显的毒杀作用.美丽海绵可能通过这些活性化合物的协同作用来防止它种生物附着污损.     

The use of computer-assisted motion analysis for quantitative studies of the behaviour of barnacle (Balanus amphitrite) larvae

The effects of larval density and age on pre-settlement swimming behaviour of Balanus amphitrite cyprid larvae were studied with the aid of computer-assisted motion analysis. Swimming behaviour was monitored in individual, in groups of 10-15 and in groups of 50-100 cyprids. There was a small, but significant effect of larval density on swimming speed and no effect on two other quantitative measures: rate of change of direction and net-to-gross displacement ratio. There was also small but significant variation in swimming speed between different batches of cyprids over the course of 2 years. Swimming behaviour of individual cyprid larvae was also monitored daily for 7 days, with the larvae maintained in the cold and dark between measurements to prevent settlement and metamorphosis. There were no significant behavioural differences observed over time indicating that larvae may be held in this manner experimentally without affecting these parameters.     

Effects of two oil dispersants on phototaxis and swimming behaviour of barnacle larvae

The effects of two oil dispersants (Vecom B-1425 GL and Norchem OSD-570) mixed with diesel oil on the survival and behaviour of the stage II nauplii of the barnacle Balanus amphitrite were investigated. The24 and 48-hour LC₅₀ values for Vecom B-1425 GL:diesel mixture were 514 and 48 mg l₋₁ respectively, while respective values for Norchem OSD-570:diesel mixture were 505 and 71 mg l₋₁. Under sublethal concentrations, increased levels of the dispersant:diesel mixtures caused a reduction in phototactic responses. Balanus amphitrite nauplii failed to exhibit phototactic responses when exposed to Vecom B-1425GL:diesel mixtures of 400 mg l₋₁ and higher for 24 hours. A longer exposure time of 48 hours further reduced the Lowest Observable Effect Concentrations (LOECs) to 60 mg l₋₁. The LOECs for Norchem OSD-570:diesel mixtures under exposure periods of 24 and 48 hours were 400and 80 mgl₋₁ respectively. The curvilinear velocities (VCL) and straight-line velocities (VSL) of the stage II nauplii ranged from 0.7–1.1and 0.2-0.4 mms₋₁ respectively. Increased concentrations of dispersant:diesel mixtures caused a significant change in the curvilinear and straight-line velocities. Both oil dispersants, dispersant:diesel mixtures of 20 to 40 mgl₋₁ caused significant increases in VCL, but no significant change in VSL. Dispersant:diesel mixtures of 100 mg l₋₁ and higher resulted in a reduction in VSL for both dispersants. This revised version was published online in August 2006 with corrections to the Cover Date.     

Microcalorimetric characterization of seasonal metabolic trends in marine microcosms

A microcalorimetric and oximetric circulation system has been used to describe the emergence of seasonal adaptative changes occurring in marine microcosms at the water-sediment interface. The microcosms were prepared from three stations: one estuarine and two lagoonal. They were submitted to the same acute eutrophication, using peptone, and the evolutions shown by power-time and oxygen-time curves were compared over a 2-yr period. The metabolic heat productions and their oxidative counterparts are well correlated with seasonal trends. In summer, the microcalorimetric curves are typically unimodal, with very low dispersion, and a low thermodynamic steady state is attained in a few hours (40–50 μW), indicating an efficient, integrated regulatory mechanism; oxygen conditions evolute towards anoxia within 6 to 8 h. In winter, the power-time curves are typically sigmoid, with low dispersion; the thermodynamic steady state attained indicates a high maintenance energy requirement (140–150 μW), probably due to microbial populations less adapted to eutrophication stress. In winter, oxygen depletion is only partial and a plateau is attained within limits of 80 to 40% of initial saturation, and lasts 1 wk at least. Spring and autumn responses are very heterogeneous, varying from summer to winter types and displaying evolutive bimodal patterns. The sea-water-sediment interfaces from different estuarine and lagoonal habitats with distinct physical and chemical characteristics, but subjected to similar environmental and seasonal perturbations, show similar energetic patterns according to the seasons. It is proposed, as a working hypothesis, that the seasonal variations of the microcalorimetric response to experimental eutrophication are the expression of a global homeostatic adaptative memory, determined by natural environmental perturbations. Spring and autumn can be considered as intermediate periods within which a seasonal “adaptative memory” is replaced gradually by another one. The heterogeneity of the microcalorimetric response in spring and autumn microcosms could be related to an asynchronous maturation for the different components of the benthic ecosystem.     

Organization of Interna in Sacculina polygenea (Crustacea: Rhizocephala)

We performed histological studies on trophic and reproductive systems of colonial interna in Sacculina polygenea, a parasite of the coastal crab Hemigrapsus sanguineus. The trophic system that performs functions of absorption, accumulation, and transportation of nutrients from the hemolymph of the host comprises the trophic epithelium of distal canals and transporting trunks. The reproductive system of interna consist of nuclei (early stages of development of the primordia of externae) and the primordia of externae in later stages of development. It has been shown that during morphogenesis of the nucleus two primordia arise, a primordium of the externa itself and a primordium of its trophic system. In the primordium of the ovary, we found oogonia; early oocytes and vitellogenic oocytes were found in the ovaries of the late primordia of the externae. The damaging effects of the interna on the ovaries and testes of the crab host are discussed. Thus, we have found numerous elements of reproductive and trophic systems in the colonial interna of S. polygenea. The term individual is proposed to be used for the externa in rhizocephalan barnacles with its trophic system.     

Semi-mass culture of the dinoflagellate Gymnodinium splendens as a live food source for the initial feeding of marine finfish larvae

A technique was developed for the semi-mass culture ofthe unarmored dinoflagellate, Gymnodiniumsplendens under laboratory conditions. A maximumcell density of 4600 to 6800 cells ml^–1 was observedwithin 8 to 11 days of culture. An initial feedingtest for 8 days with three important marine finfishlarvae showed that red spotted grouper, Epinephelus akaara preferred G. splendensfed 200 cells ml^–1 with 44% survival. The Japanesestripe knife jaw, Oplegnathus fasciatus,attained 22% survival fed a combination of G. splendensand rotifers (200 cells ml^–1 and 5ind. ml^–1, respectively). Red sea bream, Pagrusmajor larvae did not respond well to the initialfeeding of G. splendens alone. Red seabream were observed to be solely dependent on rotifers(5 ind. ml^–1) as initial food. Gymnodiniumsplendens may be used as a live food in the initialfeeding of red spotted grouper larvae (E. akaara) toreduce mortality and to further enhancegrowth during the critical first few days ofrearing.     

Organization of the Interna of the Rhizocephalan Barnacle Peltogasterella gracilis

We carried out an in vitro histological and TEM investigation of the organization of the interna of Peltogasterella gracilis(Crustacea: Rhizocephala), a parasite of the hermit crab. The colonial interna of P. gracilisincludes a reproductive system with multiple nuclei (externa rudiments) and a trophic system of absorbing lampbrush and transportation canals. The nucleus forms a cluster of embryonic stem cells. In the distal parts of the trophic system, there are cells that function in the absorption, processing, and storage of trophic substances. Cells filled with trophic resources disintegrate (evidently by apoptosis), releasing trophic substances and cell remnants into the canal cavity formed through this process. The parasitic phase of the P. gracilislife cycle is characterized by the loss of the basic morphological features and complete pattern of organization of the arthropods and by chaos and fractalization in the interna.     

Ultrastructural investigations on the muscular systems in the barnacle, Tetraclita squamosa japonica

Four muscular systems of the Tetraclita squamosa barnacle were observed by means of an electron microscope and it was revealed that these systems each bore different types of muscle cells. The four systems were the adductor (A), the lateral scutal depressor (LSD), the ventral scutal depressor (VSD), and the tergal depressor (TD). The A-system included cross stiated muscle cells which showed long sarcomeres (about 10 μm) and rather disordered arrays of myofilaments. The LSD-system included cross striated muscles which had medium length sarcomeres (about 6.7 μm) and rather ordered myofilamental arrays. The VSD-system was constructed of cross striated muscle cells which bore shorter sarcomeres (4.6 μm) than the previous three systems and ordered myofilamental arrays. This last type of cell also bore well-developed sarcoplasmic reticular systems. The TD-system included smooth muscle cells which showed rather ordered arrays of myofilaments and dense-bodies. Each muscular system, as described above, included to its advantage one type of cross striated or smooth muscle cell for its characteristic contraction. The relations between ultrastructures and functions of each muscular system will now be discussed.     

Rotifers as food in aquaculture

The rotifer Brachionus plicatilis (O.F. Muller) can be mass cultivated in large quantities and is an important live feed in aquaculture. This rotifer is commonly offered to larvae during the first 7–30 days of exogenous feeding. Variation in prey density affects larval fish feeding rates, rations, activity, evacuation time, growth rates and growth efficiencies. B. plicatilis can be supplied at the food concentrations required for meeting larval metabolic demands and yielding high survival rates. Live food may enhance the digestive processes of larval predators. A large range of genetically distinct B. plicatilis strains with a wide range of body size permit larval rearing of many fish species. Larvae are first fed on a small strain of rotifers, and as larvae increase in size, a larger strain of rotifers is introduced. Rotifers are regarded as living food capsules for transferring nutrients to fish larvae. These nutrients include highly unsaturated fatty acids (mainly 20: 5 n–3 and 22: 6 n–3) essential for survival of marine fish larvae. In addition, rotifers treated with antibiotics may promote higher survival rates. The possibility of preserving live rotifers at low temperatures or through their resting eggs has been investigated.     

Antifouling properties of tough gels against barnacles in a long-term marine environment experiment

In the marine environment, the antifouling (AF) properties of various kinds of hydrogels against sessile marine organisms (algae, sea squirts, barnacles) were tested in a long-term experiment. The results demonstrate that most hydrogels can endure at least 2 months in the marine environment. In particular, mechanically tough PAMPS/PAAm DN and PVA gels exhibited AF activity against marine sessile organisms, especially barnacles, for as long as 330 days. The AF ability of hydrogels toward barnacles is explained in terms of an ‘easy-release’ mechanism in which the high water content and the elastic modulus of the gel are two important parameters.     

Adaptive Responses of the Larvae of Cirripede Barnacle Peltogasterella gracilis to Changes in Seawater Temperature and Salinity

The responses of the larvae of the cirripede barnacle Peltogasterella gracilis (Crustacea: Cirripedia: Rhizocephala) that parasitizes the hermit crab Pagurus pectinatus to different combinations of seawater temperature (25, 22, 20, 16, and 12°C) and salinity (from 34 to 8) were studied in a laboratory. The nauplii of P. gracilis completed the entire cycle of development at 22 to 12°C in a narrow range of salinity (from 34 to 28), which agrees well with the environmental conditions of the crab hosts' habitat. At favorable temperatures (22–20°C) and salinity (34–28), the nauplii reached the cypris stage in 88 ± 2 h, while at 12°C and 34–30, the naupliar development took 156 ± 5 h. The cypris larvae appeared more resistant compared with the nauplii, in terms of changes in both the temperature and salinity of seawater. They actively swam at all experimental temperatures and in the salinity range of 34–18. At temperatures (22–16°C) and salinities (34–24) favorable for the cyprids, their longevity in plankton equaled 6–10 days. Thus, the nauplii of P. gracilis is the more vulnerable stage of development in the life cycle of this parasitic barnacle. The tolerance against changes in environmental factors is due to the adaptive capabilities of parasitic larvae and the environmental conditions in the habitats of its host, a typical marine crustacean. The insignificant parasitization rate of the hermit crab by its rhizocephalan parasite may be explained by the death of the nauplii of P. gracilis, which occurs when they enter to the surface water layer.     

Lethal and sub‐lethal impacts of pulsed laser irradiations on the larvae of the fouling barnacle Balanus amphitrite

Laboratory experiments were conducted to study the impact of laser irradiation on the larvae of the fouling barnacle Balanus amphitrite. Research pertaining to fouling invertebrate larvae‐laser interaction is sparse and, hence, data on this aspect were thought significant in order to consider pulsed low power laser irradiations as a possible future antifouling tool. Lethal and sub‐lethal impacts of four very low laser fluences, viz. 0.013, 0.025, 0.05 and 0.1 J cm^‐2 for three different durations, viz. 2, 10 and 30 s were investigated. Three growth stages of barnacle larvae, viz. nauplii stage II, nauplii stage IV and cyprids were exposed to the mentioned laser fluences for different durations. While lethal impact was assessed immediately after and 1 d after irradiation, sub‐lethal impacts were studied by monitoring the success rate of the irradiated nauplii in reaching the cyprid stage. In addition, the swimming speed of VI^th stage nauplii after irradiation was studied. In the case of cyprids, in addition to the mortality measurement immediately after and 1 d after irradiation, the settlement rate was investigated. In all the above experiments, non‐irradiated larvae served as controls. The results showed an increase in mortality with increasing laser fluence and duration of irradiation. Irradiation for 2 s resulted in significant mortality in nauplii, while it was less in the case of cyprids. In II^nd stage nauplii, the mortality immediately after irradiation for 2 s varied from 14.8±2.12 to 97.1±4.1% for laser fluences of 0.013 and 0.1 J cm^‐2, respectively. However, in cyprids, the mortality immediately after irradiation for 2 s varied from 12.2±3 to 13.4±1.2% for fluences of 0.013 and 0.1 J cm^‐2, respectively. The mortality in IV^th stage nauplii was less than that for II^nd stage nauplii but more than that for cyprids. There was a significant increase in mortality with time after irradiation. The formation of cyprids from the irradiated larvae was significantly less than that observed for non‐irradiated larvae. Also, the irradiated larvae showed a significantly slower swimming speed compared to the control samples. The settlement rate in cyprids was reduced significantly by the laser irradiation. This was true even for the lowest fluence and shortest period of irradiation tested. Thus, the results of the experiment showed that even a low power pulsed laser irradiation of 0.013 J cm^‐2 for 2 s can cause significant damage to fouling barnacle larvae.     

Molecular Detection of Marine Invertebrate Larvae

The ecological patterns of many invertebrate larvae remain an ongoing mystery, in large part owing to the difficult task of detecting them in the water column. The development of nucleic-acid–based technology has the potential to resolve this issue by direct identification and monitoring of embryonic and larval forms in situ. We report herein on the successful development and application of nucleic-acid–based sandwich hybridization assays that detect barnacles using rRNA-targeted probes with both group-(order Thoracica) and species-(Balanus glandula) specificity. Primary results include the determination of target 18S rRNA sequences and the construction of “capture” probes for detection of larvae using hybridization techniques. In addition, we modified existing protocols for whole cell hybridization of invertebrate larvae as confirmation of the sandwich hybridization results. We used both hybridization techniques successfully in the laboratory on a plankton time series collected over 3 months, as well as a week-long in situ deployment of the technique in Monterey Bay, CA. The adaptability of this technology promises to be further applicable to various organisms and could be used to enhance our understanding of larval presence in the world's oceans.