Peroxidase activity in the brown alga Laminaria digitata

Cell-free extracts of the brown alga Laminaria digitata catalyse the oxidation of o-dianisidine and of iodide, as well as the formation of iodoamino acids. The enzyme(s) requires hydrogen peroxide for these activities, which are strongly inhibited by cyanide and azide. It is suggested that the activity may be due to a haem-containing peroxidase which, in extracts, is strongly bound, possibly to alginate.     

Lignicolous marine fungi in the Straits of Messina,Italy

The occurrence and distribution of lignicolous marine fungi in the Straits of Messina has been studied. Using submerged panels of pine, beech and poplar, twenty fungal species were identified. The lignicolous mycoflora of the Messina Straits was not significantly different from that reported in the literature for other temperate marine coastal environments, Ascomycotina being frequent, while Basidiomycotina were rare.     

Carbohydrate Reserve and Dark Carbon Fixation in the Brown Macroalga, Laminaria hyperborea

Tissue discs originating from young, growing blade areas and from adult, mature frond regions of the brown macroalga Laminaria hyperborea (Fosl.) Gunn. (Phaeophyceae, Laminariales) were investigated with particular regard to photosynthesis, dark respiration, dark carbon fixation, and carbohydrate reserves. It was found that the mannitol/laminaran reserve of the young, developing blade meets the requirements of dark respiratory metabolism for only 7-10d at 10±2 °C under continuous darkness. A concomitant decrease in the potential for (β-carboxylation of phosphoenolpyruvate by phosphoenolpyruvate carboxykinase (EC 4.1.1.32) occurred along with the depletion of the stored carbohydrate. Restoring the intracellular pool of reserve carbohydrates by photosynthesis and by feeding of exogenously supplied mannitol resulted in a short term recovery of the rates of dark fixation. These findings support the view that (i) in the dark the substrate of (β-carboxylation is mainly derived from mannitol (along with glycolytic degradation of laminaran) and (ii) the young blade is not able to maintain its own carbon balance under the environmental conditions during midwinter and early spring, but relies on a carbon flow from the old blade.     

Detection and enumeration of Arcobacter spp. in the coastal environment of the Straits of Messina (Italy)

Seawater and plankton samples from the Straits of Messina, Italy, were analysed to confirm the occurrence of potentially pathogenic Arcobacter butzleri, A. cryaerophilus and A. skirrowii. Both classical cultural methods and molecular techniques were used as confirmative steps of the growth in enrichment broth to enumerate and differentiate these bacteria. Only A. butzleri was isolated from seawater and plankton samples and was more abundant when associated with plankton than free-living. A. cryaerophilus was occasionally detected by PCR assay from environmental samples. The PCR procedure, used in a combined method, was useful in enumerating Arcobacter spp. in marine environment.     

Seasonal variation in the chemical composition of the bioenergy feedstock Laminaria digitata for thermochemical conversion

To avoid negative impacts on food production, novel non-food biofuel feedstocks need to be identified and utilised. One option is to utilise marine biomass, notably fast-growing, large marine ‘plants’ such as the macroalgal kelps. This paper reports on the changing composition of Laminaria digitata throughout it growth cycle as determined by new technologies. The potential of Laminaria sp. as a feedstock for biofuel production and future biorefining possibilities was assessed through proximate and ultimate analysis, initial pyrolysis rates using thermo-gravimetric analysis (TGA), metals content and pyrolysis gas chromatography-mass spectrometry.Samples harvested in March contained the lowest proportion of carbohydrate and the highest ash and alkali metal content, whereas samples harvested in July contained the highest proportions of carbohydrate, lowest alkali metals and ash content. July was therefore considered the most suitable month for harvesting kelp biomass for thermochemical conversion to biofuels.     

Occurrence of Helicobacter pylori DNA in the coastal environment of southern Italy (Straits of Messina)

AIMS: The occurrence of Helicobacter pylori in the coastal zone of the Straits of Messina (Italy) as free-living and associated with plankton was studied. METHODS AND RESULTS: Monthly sampling of seawater and plankton was carried out from April 2002 to March, 2003. All environmental samples analysed by cultural method, did not show the presence of H. pylori. The DNA extracted from all environmental samples was tested by PCR by using primers for H. pylori 16S rRNA, ureA and cagA. 16S rRNA PCR yielded amplified products of 522-bp in 15 of 36 (41.7%) of the environmental samples. By using the ureA primers to amplify the urea signal sequences, the predicted PCR products of 491-bp were obtained from eight (22.2%) of 36 environmental samples. PCR with cagA primers yielded amplified products of 349-bp in DNA extracted of seven of 36 (19.4%) of the environmental samples. When 16S rRNA, ureA and cagA amplified gene sequences were aligned with H. pylori 26695 and J99 genome sequences, we obtained a percentage of alignment over 90%. CONCLUSIONS: The detection of H. pylori genes in marine samples allows us to consider the marine environment a possible reservoir for this pathogenic bacterium. SIGNIFICANCE AND IMPACT OF THE STUDY: The direct detection of H. pylori genes may be relevant in order to consider the marine environment as significant reservoir for this bacterium.     

An ecological study of fucus spiralis L.

An ecological study of Fucus spiralis L. has been made at Jaffrey Point, Newcastle, New Hampshire and the adjacent Great Bay Estuary System from 1972–1975. The distribution, growth, reproductive periodicity, attrition and longevity of the plants are described in relation to a variety of environmental factors. F. spiralis shows a broad but discontinuous estuarine distribution within the Great Bay Estuary System. The presence or absence of appropriate substrata is considered to be a factor determining its discontinuous distribution, since it is usually associated with metasedimentary or metavolcanic rock outcrops. The maximum growth and reproduction of F. spiralis are during the summer. The summer growth rates ranged from 1.9 to 2.8 cm/month while the average growth rate throughout the year was 1.2 cm/month.F. spiralis populations showed two periods of major attrition, namely, during the winter and summer. The average longevity of F. spiralis plants is ≈ 2 yr. The F. spiralis zone lies in the uppermost intertidal area between +2.12 and +2.31 m above M.L.W. There is a micro-stratification of biomass, stature, and reproductive activity within this zone. Average plant weight, length, and fertility tend to decrease with increasing elevation.     

Spore liberation in Gracilaria corticata J. Agardh growing at Mandapam

Seasonal and diurnal changes in the spore liberation of Gracilaria corticata J. Agardh and the effect of exposure to air and light and dark periods on spore output have been studied. Tetraspore and carpospore shedding was found in all months of the year with a maximum output in March–April and again between September and December. Spore output varied at different times of the day and the highest values were recorded at night. Exposure to air and photoperiod affected spore production and the maximum liberation was observed in submerged fronds kept in complete darkness. Viability of tetraspores was low under laboratory conditions and only 26% of germlings were found in a healthy condition at the end of one month.     

华南五针松濒危机制生态学研究

为了揭示珍稀濒危特有种华南五针松天然种群的生存状况,在全面调查广东南岭国家级自然保护区华南五针松分布的基础上,结合文献收集法,利用群落内不同乔木的胸径、树高、冠幅等指标,计算不同海拔梯度内华南五针松种群的平均生存压力,分析不同海拔梯度内华南五针松种群的空间格局。结果表明：1)、海拔高度和温度影响群落的空间格局,沿994m至1600m的海拔梯度上华南五针松种群空间格局以聚集为主,且随海拔的升高,种群聚集强度增加,当达到1600m时,聚集强度降低,种内和种间竞争减缓,生存压力变小;2)、华南五针松种群平均生存压力指数总体沿海拔梯度上升呈递减趋势(R²=0.31,P<0.05),中低海拔华南五针松种群生存压力较大,高海拔聚集强度降低,生存压力减小,华南五针松有向高海拔迁移的可能,当达到1710m以上时,最终会因分布区逐渐缩小、生存环境恶劣和不适应等因素造成最终灭绝;3)、群落种间结构的复杂性造成种间和种内竞争激烈,同一海拔梯度上华南五针松种群平均生存压力指数不同;4)、针对华南五针松人工林,种群平均生存压力指数为50,受到来自竞争树种的威胁大,需加以严格保护。华南...     

Observations on the ecology of Membranipora (bryozoa) and a major predator Doridella steinbergae (nudibranchiata) along the fronds of Laminaria saccharina at Friday Harbor,washington

The distribution of the bryozoan Membranipora and one of its major predators, the nudibranch Doridella steinbergae (Lance) along the fronds of Laminaria saccharina (L.) Lamour. at Friday Harbor, Washington were studied during the summer (July–August) 1975. Whilst the fronds are most heavily encrusted by the bryozoan in the middle and distal regions, settlement occurs principally in the younger more basal regions of the plants. The distribution pattern of the nudibranch closely parallels that of its prey though there is a tendency for the most distal regions, especially in older plants, to be avoided. An average density of 240 Doridella/plant was found for plants of mean length 91.0 cm. Despite the severe predation pressure imposed by this nudibranch, evidence tends to suggest that these extensive and highly productive Membranipora populations could probably support even higher densities of Doridella than those presently found — at least over that period of the year during which this investigation was made.     

An ecological study of the Ponggol Estuary in Singapore

1. An ecological study of the Ponggol Estuary was conducted from July 1965 to June 1966 and the seasonal data on physical, chemical and biological characteristics were presented.
2. The Ponggol River represents a short, narrow and shallow estuary in Singapore. The river mouth is open throughout the year and water from eastern Johore Straits drains in twice a day at high tide. The upper reach, however, is left exposed at low tide.
3. The Ponggol River was classified as a vertically and laterally homogeneous estuary and was found to exhibit a mesohaline to polyhaline environment.
4. Significant hydrological gradients from the river mouth 10 the upper reach were noted in the river system. Salinity, dissolved oxygen and pH increased towards the mouth of the river and other parameters such as nutrients, dissolved organic matter and turbidity increased towards the source.
5. Although the river received organic pollutants at the upper reach the estuary was able to discharge them fairly rapidly through regular flushing by the tides. The transient rise of organic matter did not appear to impart any serious affect on the biota in the estuary.
6. Over 98% of the phytoplankton consisted of diatoms, most of which were brought into the estuary from eastern Johore Straits. Freshwater forms were relatively few.
7. Phytoplankton biomass was considerably higher than the adjoining waters. and was reduced at the upper reach due to high turbidity of the water.
8. 80% of the zooplankton was composed of dinoflagellates,Difflugia, copepods and bivalve larvae dominating at all sections of the estuary.
9. Percentage composition of the zooplankton showed that dinoflagellates and copepod nauplii predominated at high tide whileDifflugia and bivalve larvae were abundant at low tide.
10. Zooplankton standing crop, in general, was higher towards the source at high tide but the reverse was found at low tide, i.e. standing crop increased towards the river mouth. This was attributed to the process of concentration.
11. Species composition of zooplankton was found to be more or less similar to that of the eastern Johore Straits.
12. The nekton consisted predominantly of small and juvenile fish. Close correlation of fish and copepods was found to be statistically valid and it was concluded that the fish entered the estuary to feed rather than to spawn.
13. The squids formed an important catch of the beach seine unit and were caught throughout the year.
14. The fish population could be grouped into four categories: estuarine components, euryhaline components, marine components and migratory components.
15. Benthic invertebrates were abundant. Commercially important species consisted of prawns,Metapenaeus andPenaeus, and crabs,Neptunus pelagicus andScylla serrata.
16. The river bed was inhabited predominantly by molluscs and the distribution resembled that of the sheltered shore of muddy-sand type.

     

Degradation of Laminaria japonica fucoidan by hydrogen peroxide and antioxidant activities of the degradation products of different molecular weights

Conditions of fucoidan degradation by hydrogen peroxide and the antioxidant activities of fucoidans with different molecular weights (Mws) were studied. Fucoidan degradation was monitored by gel permeation chromatography (GPC). Results showed that higher reaction temperature, hydrogen peroxide concentration and reaction time were the main factors that determined the decrease in Mw. There were no significant chemical changes in the backbones of the fucoidans treated with hydrogen peroxide, and the sulphate group contents barely change as compared to the raw polysaccharide. The antioxidant activities of seven fucoidans with different Mws (1.0 kDa, 3.8 kDa, 8.3 kDa, 13.2 kDa, 35.5 kDa, 64.3 kDa, 144.5 kDa) were assessed. The results showed that the relationship between Mws of fucoidans and their antioxidant activities is not simply linear. The samples with Mws of 3.8 kDa, 1.0 kDa and >8.3 kDa have better hydroxyl radical scavenging activity, reducing power and superoxide anion scavenging activity, respectively.     

Induction of phosphoribomutase in Bacillus cereus growing on nucleosides

In this paper we show that phosphoribomutase is induced in Bacillus cereus by the same metabolizable purine and pyrimidine ribonucleosides previously shown to induce the purine nucleoside phosphorylase (Tozzi, M.G., Sgarrella, F. and Ipata, P.L. (1981) Biochim. Biophys. Acta 678, 460–466). The mutase allows ribose 1-phosphate formed from nucleosides to be utilized by the cell through the pentose cycle, upon transformation to ribose 5-phosphate. The equilibrium constant of the mutase reaction is towards ribose-5-phosphate formation. The coordinate induction of the two enzymes completes the picture of the molecular events leading to the utilization of the sugar moiety of purine nucleosides and nucleosides as an energy source (Mura, U., Sgarrella, F. and Ipata, P.L. (1978) J. Biol. Chem. 253, 7905–7909).     

Spatial and temporal distributions of dominant epiphytes on the stipes of Laminaria hyperborea (Gunn.) Fosl. (Phaeophyta:Laminariales) in S.E. Scotland

The epiphytic flora of the stipes of Laminaria hyperborea (Gunn.) Fosl. at St. Abbs Head, Berwickshire, Scotland has been examined. Four species Palmaria palmata (L.) O. Kuntze, Ptilota plumosa, (C. Ag.) Huds., Membranoptera alata (Huds.) Stackh., and Phycodrys rubens (L.) Batt. make up > 95% of the epiphyte biomass. The species show two distinct patterns of zonation, one with depth the other with respect to position on the host stipe. Palmaria is found on the upper parts of the stipes at 1 and 2 m depth, with the three other species found lower on the stipe. At 6 m depth Ptilota occupies the position on the stipe where Palmaria had occurred in the shallower water. In the deepest samples (12m) Ptilota was absent and its position on the stipe was occupied by Phycodrys and Membranoptera. This zonation is reflected in the biomass of the epiphyte species, Palmaria is restricted to the shallow waters, Ptilota reaches its greatest biomass at intermediate depths while Membranoptera and Phycodrys are most abundant at 6 m and below. Palmaria, Membranoptera, and Phycodrys show similar patterns of seasonal changes in epiphyte biomass with a peak in September and a decline in winter. Ptilota, which in the British Isles is considered to be a species of northern distribution, shows an earlier peak biomass and a correspondingly earlier decline in abundance.     

The first stage larva of brugia pahangi in Aedes togoi: An ultrastructural study

Lehane M. J. 1978. The first stage larva of Brugi pahangi in Aedes togoi: an ultrastructural study. International Journal for Parasitology8: 207–218. The ultrastructure of the first stage larva in the mosquito is described up to the onset of the first cuticular moult. The following structural changes from the microfilarial stage have been noted at this time; the numbers of muscle cells have increased, usually to four with a maximum of six in each intercordai quadrant ; part of the pharyngeal thread has formed into a knot ; the intestinal lumen has developed and is surrounded in any given transverse section by up to four intestinal cells and the inner body has largely been lost; the anal apparatus has enlarged and developed; the excretory apparatus has largely degenerated. The functional morphology of the various organ systems described is discussed.     

An observational study of scent-marking in coyotes, Canis latrans

Urination and defaecation patterns of free-ranging coyotes (Canis latrans) were studied in the Grand Teton National Park, Jackson, Wyoming, for two years. The vast majority of urinations by adult males and females were involved in ‘marking’, and differentiating between ‘marking’ and ‘elimination’ may not be necessary. Our results may be summarized as follows: (1) raised-leg urinations (RLU) performed by males were most frequently used in marking. (2) Females marked throughout the year using the squat (SQU) posture. (3) Snow tracking and reading snow sign resulted in a gross underestimate of the relative frequency of SQU's and a large overestimate in the relative frequency of defaecations (DEF) when compared to results obtained by direct observation. (4) There was sexual dimorphism for the contexts in which marking occurred. Overall, marking by males was associated with courtship and mating, with travelling, and with aggression. Marking by females was associated with the acquisition and possession of food and with the denning season. (5) Marking rates per coyote increased in groups larger than two animals. (6) RLU marking rates were greatest in areas of high intrusion when compared to denning areas and areas in which non-group members infrequently tresscent odours are important in orienting individuals in space but do not represent in and of themselves barriers to movement.     

Structural analysis of a highly sulfated fucan from the brown alga Laminaria cichorioides by tandem MALDI and ESI mass spectrometry

Water-soluble polysaccharide fractions were extracted from the brown alga Laminaria cichorioides. Samples were collected monthly from May to October in Troitsa Bay (Japan Sea, Russia). Analysis showed that the content and monosaccharide composition of the fractions changed with the collection season. Fucoidan was isolated and purified from the most fucose-rich fraction, collected in July, and subjected to autohydrolysis to obtain fucooligosaccharides, suitable for mass-spectrometric analysis. Both ESIMS and MALDI-TOFMS analyses show that multisulfated (up to 3) fucooligosaccharides with polymerization degree n from 2 to 5, including mono- and disulfated-fucose residues, were the major products of autohydrolysis. The structural features of the fucooligosaccharides and their alditol derivatives were elucidated by tandem MALDI-TOFMS and ESIMS. The results obtained allowed us to conclude that fragments of the fucoidan, collected in July, were predominantly linked with a (1→3)-type of linkage and that sulfate groups occupied mostly C-2 or C-2/C-4 of the α-l-fucose residues.