Showing papers by "National Institute of Oceanography, India published in 1997"

Identification of cylindrospermopsin in aphanizomenon ovalisporum (cyanophyceae) isolated from lake kinneret, israel1

Abstract: Aphanizomenon ovalisporum (Forti) was identified and isolated from Lake Kinneret upon its first appearance as a dominant bloom in late 1994. This cyanobacterial species, not previously known to be toxic, was evaluated by a commonly used mouse bioassay and was demonstrated to induce toxic symptoms that were distinguishable from the typical symptoms of the neurotoxins previously reported in Aphanizomenon flos-aquae (L.) Ralfs. Mice died 5–24 h after crude extracts were injected intraperitoneally, and the LD50 value was estimated as 465 mg dry wt biomass · kg−1 mouse. A toxicity-guided fractionation of the active extract indicated that the potent substance is polar an nature. The structure of the active compound was determined by its mass spectrometry and NMR data. The compound was found to be the sulfate-guanidinium zwitterion, cylindrospermopsin, previously isolated from the cyanobacterium Cylindrospermopsis raciborskii (Woloszynska) and recently also reported in Umezakia natans (Watanabe). This is the first time that Aphanizomenon ovalisporum has been reported to contain a toxic compound.

Litter Fall and Energy Flux in a Mangrove Ecosystem

Abstract: Production, elemental composition andin situdecomposition of litter ofRhizophora apiculata,R. mucronata,Sonneratia albaandAvicenna officinaliswere studied in a mangrove ecosystem fringing Madovi–Zuari Estuaries on the Central West Coast of India. Litter yield ranged from 10.2 tonnes ha-1year-1inA. officinalisthrough 11.8 (R. apiculataandR. mucronata) to 17 tonnes ha-1year-1inS. alba. Seasonally maximum litter fall was in pre- and post-monsoon monthe, with the lowest production in the monsoon. Modelling of litter fall as a function of Julian day and six environmental parameters showed that the observed changes can be explained in terms of dry/wet season and wind speed, with a 1000. Total decomposition (98–100% loss in dry weight and C, and >90% loss in N and P) of yellow leaves was within 15 weeks in the twoRhizosporaspp. andS. alba, and within 8 weeks inA. officinalis. In all four species, mass changes during decomposition obeyed first-order kinetics. Comparison of C, N and P fluxes from the decomposing mangrove litter with phytoplankton, bacterial and secondary production in the estuarine waters showed that mangrove production is important mainly for the C budget of the Estuaries and in sustaining the microbial food chain and nutrient regeneration, rather than the particulate food chain directly.

Alloimmune maturation in the coral Stylophora pistillata is achieved through three distinctive stages, 4 months post–metamorphosis

Abstract: Adult colonies of the reef–building coral Stylophora pistillata discriminate precisely between ‘self’ and ‘non–self’ attributes and respond selectively against specific allogeneic challenges. We studied the ontogeny of these allospecific responses on newly settled polyps by establishing allogeneic contacts within groups of 2–6 siblings or non–related offsprings. Interactions were observed for up to 8 months. Three types of responses, depending on the age of the interacting partners, were documented. The first was tissue fusion and the formation of a stable chimera, observed in partners less than 2 months old. The second was observed in contacts of partners 2–4 months old. It started with tissue fusion and transitory chimera since separation of the chimera–partners or polyp death resulted when the oldest partner in the chimera reached the age of 4 months. The third type was the regular histoincompatibility response, as documented in allogeneic interactions of adult colonies, recorded here in all encounters with S. pistillata partners over 4 months old. Maturation of allorecognition in this species was therefore achieved through three time–dependent stages, 4 months following metamorphosis. Combinations of siblings or genetically unrelated partners did not affect the results. We propose that the coral alloimmune maturation system may be used as a new evolutionary model scheme for studying tissue transplantation and tolerance.

Isolation and characterization of the high-density lipoproteins from the hemolymph and ovary of the penaeid shrimp Penaeus semisulcatus (de Haan): apoproteins and lipids.

Abstract: The high-density lipoproteins (HDLs) found in the male and female hemolymph of Penaeus semisulcatus de Haan were isolated by NaBr (122 g/ml) followed by sucrose gradient (5-25%) ultracentrifugation The male HDL contained one protein, lipoprotein 1 (LP1), composed of one 110-kDa peptide subunit The female HDL contained two proteins: 1) the LP1 that was immunoidentical to the male LP1 and was similarly composed of one 110-kDa peptide subunit and 2) vitellogenin (Vg), reacting positively with the rabbit antiserum generated against vitellin (Vt) that was isolated from vitellogenic ovaries Both Vg and Vt consisted mainly of three polypeptide subunits (200, 120, and 80 kDa) as revealed by denatured PAGE and Western blot The LP1 from males or females did not react with the Vt rabbit antiserum Similarly, Vg and Vt did not react with the rabbit antiserum prepared against LP1 Phospholipids (PL) constituted 71-76% of the total lipids in the hemolymph and HDLs of both male and female hemolymph Cholesterol (Ch) amounted to 17-20%, and small amounts (5%) of diacylglycerols (DAG) were also carried by these HDLs Both the PL and DAG contained highly unsaturated fatty acids (20:5 omega 3 and 22:6 omega 3) that are transported from the food or hepatopancreas to the tissues, including the vitellogenic ovaries in females In the present study we show for the first time the separate lipid composition of female LP1 and Vg and compare them with the lipids attached to the Vt Vg had a lower lipid content than LP1 (540 and 1089 mg/g protein, respectively) Differences were also found in the relative abundance of PL, Ch, and DAG classes in the LP1 in comparison with Vg Furthermore, small amounts (approximately 38%) of triacylglycerols (TAG) were found only in the hemolymph of vitellogenic females, and they were associated with the Vg Although Vg and Vt were composed of similar polypeptides, their lipid composition was different Vt, in contrast to Vg, carried considerable amounts of TAG (approximately 22%) and only trace amounts of DAG The significance of the TAG in the hemolymph of vitellogenic females is not known, and the functional relationship between Vg and Vt requires future extensive studies Lipids were not detected in hemocyanin that was purified from clotted hemolymph

Uptake, efflux, and photosynthetic utilization of inorganic carbon by the marine eustigmatophyte nannochloropsis sp.1

Abstract: Uptake, efflux and utilization of inorganic carbon were investigated in the marine eustigmatophyte Nannochloropsis sp. grown under an air level of CO2. Maximal photosynthetic rate was hardly affected by raising the pH porn 5.0 to 9.0. The apparent photosynthetic affinity for dissolved inorganic carbon (DIC) was 35 μM DIC between pH 6.5 to 9.0, but increased approximately threefold at pH 5.0 suggesting that HCO3- was the main DIC species used from the medium. No external carbonic anhydrase (CA) activity could be detected by the pH drift method. However, application of ethoxyzolamide (an inhibitor of CA) resulted an a significant inhibition of photosynthetic O2 evolution and carbon utilization, suggesting involvement of internal CA or CA-like activity in DIC utilization. Under high light conditions, the rate of HCO3− uptake and its internal conversion to CO2 apparently exceeded the rate of carbon fixation, resulting in a large leak of CO2 from the cells to the external medium. When the cells were exposed to low DIC concentrations, the ratio of internal to external DIC concentration was about eight. On the other hand, in the presence of 2 mM DIC, conditions prevailing in the marine environment, the internal concentration of DIC was only 50% higher than the external one.

Tidal propagation in the Mandovi-Zuari Estuarine network, west coast of India: Impact of freshwater influx

Abstract: The Mandovi–Zuari estuarine network on the west coast of India consists of shallow strongly converging channels, that receive large seasonal influx of fresh water due to the monsoons The main channels, the Mandovi and Zuari estuaries, connect the network to the Arabian Sea Observations show that tidal amplitude in the channels remains unchanged over large distances (|mS40 km) from the mouths of the main channels and then decays rapidly over approximately 10 km near the head To understand the dynamics behind this behaviour, a numerical model for tidal propagation has been used that simulates the observed tidal elevations well Momentum balance in the model is predominantly between pressure gradient and friction In the region of undamped propagation, the model behaviour is consistent with the theory that geometric amplification balances frictional decay leaving the tide unchanged This balance breaks down near the upstream end, where channels are narrowest, and mean velocity associated with freshwater influx is sufficiently large to prevent upstream propagation of tide This leads to rapid decay in tidal amplitude The model also shows that the mean water-level rises in the upstream direction, in the region of the decay

Secondary metabolites from the sponge Tedania anhelans: isolation and characterization of two novel pyrazole acids and other metabolites

Abstract: Chemical investigation of the methanol extract of the sponge Tedania anhelans yielded the two unusual heteroaromatic acids, pyrazole-3(5)-carboxylic acid (2) and 4-methylpyrazole-3(5)-carboxylic acid (3), which are reported for the first time as natural products. The other compounds isolated were p-hydroxybenzaldehyde, phenylacetamide, 3-phenylpropionic acid, 3-(p-hydroxyphenyl)propionic acid, 3-(p-methoxyphenyl)propionic acid, β-carboline (norharman) (1), and the four diketopiperazines pro-val, pro-leu, pro-phe, and pro-tyr.

Bacterial induction and inhibition of a fast necrotic response in Gracilaria conferta (Rhodophyta)

Abstract: Of 45 bacterial isolates from healthy tips of Gracilaria conferta (Schousboe ex Montagne) J. et G. Feldmann, 29% were identified as 'conditional inducers' of an apical necrosis. That is, the isolates induced necrotic tips in G. conferta within 16 h after elimination of most of the resident microflora from the alga. Several disinfectants and antibiotics were screened for their ability to induce algal susceptibility to the bacteria and to suppress uncontrolled appearance of tip necrosis. Treatment with 100 mg L-1 Cefotaxim + 100 mg L-1 Vancomycin over three days was the least damaging and most efficient. Tip necrosis was related to isolates of the Corynebacterium-Arthrobacter-group and to the Flavobacterium-Cytophaga-group. The damaging effect occurred due to the bacterial excretion of active agents and was not correlated with a capability to degrade agar. The damaging influence of four Cytophaga-like strains was inhibited by 20 of 40 isolates. This protective effect was caused by very different organisms. In five of six cases examined further, the effect was not cellbound, but due to the excretion of agents. These were not antimicrobially active, but inactivated necrosis-inducing excretions. These results indicate that epiphytic bacterial degradation or inactivation of damaging agents is a protecting factor in Gracilaria, which prevents the alga from being harmed by epiphytes.

Evidence for recent hydrothermal activity in the Central Indian Basin

Abstract: This study documents the first actual proof of recent intraplate volcanic-hydrothermal activity in the Central Indian Basin (CIB). Twenty-six surface sediments and a spade core (37 cm long) from the CIB were examined for the presence of volcanogenic-hydrothermal materials (vhm). High concentrations of vhm were discovered in a grab and the core top—both located at the base of an intraplate seamount. The vhm consist of ochrous metalliferous sediments, volcanic spherules and glass shards. The radiolaria associated with the vhm suggest a ∼ 10 ka age for the hydrothermal episode. The metalliferous sediments are semi-indurated, yellow to orange colored FeSi oxyhydroxides with FeO and Si02 contents between 54–73% and 16–30%, respectively, and have been derived as a result of hydrothermal precipitation. Incipient formation of nontronite is noted to co-occur with these sediments. The CIB metalliferous sediments have close similarities to those reported from the intraplate regions of the Pacific Ocean. The volcanic spherules occur in various shapes and sizes and are dominantly composed of magnetite and lesser amounts of ilmenite, hematite and maghemite. Electron microscopy shows the arrangement of magnetite crystals in various textural forms. Inclusions within the spherules are of olivine, pyroxene and feldspar. The spherules have formed by a process of liquid immiscibility of a silicic-basic magma, dependent on oxygen fugacity. Rhyolitic glass shards are ubiquitous at 1–2 cm depth in the core and constitute 55% of the coarse fraction. Microprobe analyses of the CIB shards show clear differences in Ti- and SiAl ratios that, together with the vast differences in age of eruption, preclude their derivation from Toba (Indonesia).

Lithogenic fluxes in the Bay of Bengal measured by sediment traps

Abstract: Lithogenic flux measured continuously for 1 year using time-series sediment traps at two sites in the Bay of Bengal show a strong seasonality with 43–49% of the fluxes to the deep traps occurring during the SW monsoon. Lithogenic fluxes increased with depth and the rate of increase was maximum during periods of high freshwater influx. Simultaneous sedimentation of lithogenic and organic matter is seen at both the sites. Clay mineral studies show that illite percentage decrease and smectite percentage increase with depth. Due to the prevailing circulation pattern, illite-rich suspended sediments from the Ganges-Brahmaputra Rivers are transported southwards in the surface low salinity layer while smectite-rich muds from the continental margins are resuspended and transported at depth in perhaps somewhat heavier clock-wise circulation.

Controls on organic carbon distribution in sediments from the eastern Arabian Sea Margin

Abstract: Sediment cores from the upper continental slope of the eastern Arabian Sea have high organic carbon (OC), CaCO3, and sand content at the top The values decrease with increasing depth in the Holocene and Upper Pleistocene Topographic highs show highest OC and lower CaCO3 in the Holocene clayey sediments and vice versa in the Pleistocene sandy sediments The OC is immature and marine or a mixture of both marine and terrestrial in the Holocene sediments and is mostly terrestrial and/or reworked marine in the Pleistocene sediments Productivity is the main controlling factor for the organic carbon enrichment Texture and reworking also influence the organic carbon variations

Mariculture in Israel : past achievements and future directions in raising rotifers as food for marine fish larvae

Abstract: Marine fish production is now being carried out after almost two decades of research The production of seabream (Sparus aurata), which reached over 750 tons in 1995, is expected to reach an annual production ranging between 4,000 – 12,700 metric tons by year 2010 The anticipated introduction of new species and its expansion to the Mediterranean shore line will help in leading the increased mariculture production Two marine fish hatcheries that operate today in Israel produce 7 million fingerlings a year Traditionally, aquaculture in Israel raises fish in inland freshwater ponds and irrigation reservoirs In addition, Lake Kinneret, the only freshwater lake in Israel, is stocked yearly with juvenile fish raised in local hatcheries (tilapia) or imported from Mediterranean countries (mugil) While culture of freshwater teleost species (carp) was introduced more than fifty years ago, mariculture started on a commercial scale less than 5 years ago The limited supply of freshwater will accelerate the future culture of marine species

Ashdod Port's Effect on the Shoreline, Seabed and Sediment

Abstract: During its 35 years of existence, Ashdod Port, Israel, caused changes to its physical environment. Analysis of aerial photographs and bathymetric surveys show that the port served as a sediment trap, blocking the natural northward sediment transport. Between 1958, prior to the port construction, and 1992 the beach to the south of the port underwent accretion which increased in magnitude from zero, at a distance of 2.5 km south of the port, to more than 100 m near the main breakwater. On the northern side of the port the shoreline was stable during that period. It was found that the beach north of the port did not suffer erosion because the sand of that beach was mined for building purposes prior to the port's construction. When the port was built, it was already a rocky beach. Comparison between bathymetric surveys, which were carried out in the vicinity of the port, at various periods since prior to its construction until 1995, show that the port has trapped some 4.5 million m3 of sediments on its southern side. Of these, about 2.2 million m3 were deposited during the period of 1985-1995. It is estimated that more than half of this volume was deposited in 1992 during three very severe storms. On the basis of the depositional pattern in the vicinity of the port, and assumptions related to the net longshore sediment transport, it is estimated that more than half of the sediment volume bypasses the port northward.

Geophysical investigations over a segment of the Central Indian Ridge, Indian Ocean

Abstract: Swath bathymetric, gravity, and magnetic studies were carried out over a 55 km long segment of the Central Indian Ridge. The ridge is characterized by 12 to 15 km wide rift valley bounded by steep walls and prominent volcanic constructional ridges on either side of the central rift valley. A transform fault at 7°45′S displaces the ridge axis. A mantle Bouguer anomaly low of −14 mGals and shallowing of rift valley over the middle of the ridge segment indicate along axis crustal thickness variations. A poorly developed neovolcanic zone on the inner rift valley floor indicate dominance of tectonic extension. The off-axis volcanic ridgs suggest enhanced magmatic activity during the recent past.

Stone anchors from Sindhudurg Fort on the west coast of India

Abstract: Introduction Seafarers have used anchors since they ventured into the sea. Various types of pierced stones were used before the manufacture of metal anchors. In India various stone anchors have been discovered during the course of exploration and excavations. Inshore explorations have been carried out in the Malwan region of Maharashtra on the west coast of India, as part of the project, 'Exploration and Excavation of Shipwrecks on the West Coast of India'. Sindhudurg (the Ocean Fort) was built between AD 1664 and 1667 by Shivaji, the Maratha king on a low lying island, about 1 km off Malwan (Fig. 1). The bay between Malwan jetty and Sindhudurg is very

Initiation of epithelial cell cultures from palleal buds of Botryllus schlosseri, a colonial tunicate.

Abstract: Dear Editor: While expertise in invertebrate tissue cuhure is still limited largely to terrestrial arthropods, the recent extensive studies on marine invertebrate immunology and developmental and cellular biology have initiated parallel efforts to develop novel tissue culture techniques in a variety of marine taxa. This is also true for tunicates (Urochordata), one of the most highly evolved invertebrate taxa, in which recent studies have shown that different types of cells are amenable to culture (5-7). As such, proliferative cultures were initiated from pharyngeal explants (5), blood cells (6), and blastomers (7). Here, we present the initiation of epithelial cell cultures from isolated palleal buds of the colonial tunicate, Botryllus schlosseri. B. schlosseri is a cosmopolitan shallow water styelid ascidian (subfamily Botryllinae), a common inhabitant of hard-bottom communities. A colony, composed of up to thousands of modular units called zooids, develops from the metamorphosed larva. The zooids are embedded within a common organic matrix (the tunic) and ordered in star-shaped structures (the systems). The tunic is traversed by a ramified vascular network connecting the zooids to each other, and to a marginal vessel from which a crown of peripheral blind projections (ampullae) are expanded. This species is characterized by a complex synchronized developmental cycle (called blastogenesis), in which at t8 -20 ° C all functional zooids degenerate once a week and a new generation of developing buds \"take over\" the colony (3). This blastogenic eyrie has been arbitrarily divided into four (termed as A-D) developmental stages (4), where stage D is represented by the degeneration phase of the old generation of zooids, and the maturation of the developing buds into the new generation of functional zooids. As a matter of fact, there are three sequential generations of zooids that are simultaneously presemed: functional adult zooids and two generations (primary and secondary) bilateral buds, which are attached to the parental zooids by vaseularized epidermal stalks. Zooids of the same generation are of the same developmental stage. Budding is palleal. A secondary bud is developed from the atrial epithelium of the primary bud and is overlaid by the epidermis (1). The present communication describes short-term proliferating epithelial cell cultures initiated from isolated primary palleal buds of 6-wk-old B. schlosseri colonies. We used laboratory bred colonies, attached to 5 X 7.5 em glass slides at the metamorphosing larval stage. Colonies were reared in a culture room (20 ° C, 14/10 light/ dark regimen) within 17-1 glass tanks supplied with standing sea water, preconditioned in 300 1 plastic holding tanks. Detailed marieutture procedures and preparations of the animals for collection ~f tissues are described elsewhere (6,7). Developing buds at blastogenic cycles A to C (sensu ref. 4) were dissected from well-developed Botryllus colonies. Sampling of buds from the selected zooids was made under the dissecting microscope using a sterile syringe equipped with a 28 G size needle. Using the needle tip, primary buds with attached secondary buds were carefully isolated from the adult zooids. They were collected by sterile Pasteur pipettes and transferred to 15 ml plastic tubes containing sterile seawater (SSW). The isolated buds were rinsed up to 10 times with SSW and transferred to 24-well plates (Nunc, Denmark), several buds from the same colony/well. For the first 48 h, the buds were incubated in incubation medium at pH 7.5, containing per 100 m]: 45.5 mg RPM[-1640, 5% dialyzed fetal catf serum (FCS), 2 ml HEPES in artificial sea water (made of two stock solutions: A = 13.67 g NaCI, 0.412 g KCI, 0.721 g CaC12\"2H=O in 125 ml double distilled water (DDW); B = 5.57 g MgSO4\"7H~O, 3.05 MgC126H20 in 125 ml DDW. The stock solutions were diluted 1:2 in DDW before use and supplemented with a \"cocktail\" of antibodies (50 mg/ml streptomycin sulphate, 5.104 IU/ml sodium penicillin salt, and 6250 IU/ml nystatin; 1 ml of antibiotic cocktail per 100 ml incubation medium). Collagenase (final concentration 0.01%) was then added for partial chemical dissociation of the buds. Following the first 48 h, the buds and medium were transferred to 2 ml sterile Eppendorf vials and centrifuged (1700 RPM, 5 rain) in a bench top centrifuge. The buds were then further dissociated mechanically by hand, using a fitted homogenizer. The resultant cultures contained single cells, cell clumps, and partly dissociated bud fragments, 50-300 gm in size. Samples of dissociated tissues were transferred to 24-well plates within 0.5 ml incubation medium per well, three to four buds/well; 0.2 ml of the medium was replaced with fresh medium every uther day. We analyzed six different treatments (Table 1) in which the incubation medium was supplemented by: 1. Fibroblast Growth Factor (FGF) (1 ng/ml); 2. heat inactivated (HI) crab (Portunus pelagicus) hemolymph (5%); 3. additional 5% (total 10%) HI dialyzed FCS; 4. fibronectin from bovine plasma (60 gg/ml); 5. Lipopolysaccharides (LPS) (10 mg/ml); 6. HI sea cucumber (Holothuria forskali) hemolymph (5%). Two experiments were run. In each, four wells/treatment were established; two wells with buds at stage B and two wells with buds at stage C. In preliminary, experiments, we found that stage A buds did not develop epithelial cell cultures (data not shown)_ The main results are summarized in Table 1. Out of the six different treatments, only cultures supplemented with FGF and with crab hemolymph resulted in cellular proliferations, characterized by the formation of flattened epithelial cell monolayers, which lasted up to 1 too. after bud samplings (Fig. 1 a-c). No differences were observed between buds of blastogenic stage B as compared to stage C. Monolayers of epithelial cells were initiated from partly dissociated buds, not from single cells or cell clumps, and only from fragments that attached to the substrate (Fig. 1 a and b). Attachment of tissue fragments to the plastic substrate (in FGF treatment) or to the overlayed organic substrate (in crab hemolymph treatment) was recorded within a few days. Within 1 wk after attachment, some of the attached fragments developed large (up to 0.4 mm) hollowed spheres. Only