The mercury binding activity of pectin isolated from the seagrass Zostera marina

The kinetics of mercury binding by pectin isolated from the seagrass Zostera marina was described, and its maximum mercury binding activity at pH from 2.0 up to 6.0 was determined. It was shown that mercury binding by pectin in in vitro conditions did not depend on concentration of hydrogen ions in the environment. The maximum mercury binding activity estimated from the Langmuir equation was 2.64 mmol/g of dry mass of the pectin.     

Metal binding activity of pectin isolated from seagrass Zostera marina and its derivatives

Low esterified pectin was isolated from the seagrass Zostera marina. Dynamics of the isolation process for the pectin from this seagrass was investigated. Two pectin derivatives: galacturonide (A) with molecular weight 30.55 kDa and galacturonide (B) with molecular weight 3.94 kDa were obtained using acidic hydrolysis of the native pectin from Zostera marina. Molecular weight parameters (Mw, Mn, Mw/Mn) of this pectin and its derivatives as well as of commercial apple pectin were determined using gel-filtration chromatography method. Comparative assessment of Cd²⁺, Pb²⁺, Y³⁺-binding activity of the native Zostera pectin, galacturonides A and B, and commercial apple pectin was performed. The results showed that galacturonide A with molecular weight 30.55 kDa possesses highest metal-binding capacity and may be considered as a candidate for development of medicines with metal-binding activity.     

Habitat suitability of the Wadden Sea for restoration of Zostera marina beds

A conceptual model is proposed, describing potential Zostera marina habitats in the Wadden Sea, based on reported data from laboratory, mesocosm and field studies. Controlling factors in the model are dynamics, degree of desiccation, turbidity, nutrients and salinity. A distinction has been made between a higher and a lower zone of potential habitats, each suitable for different morphotypes of Z. marina. The model relates the decline of Z. marina in the Wadden Sea to increased sediment and water dynamics, turbidity, drainage of sediments (resulting in increased degree of desiccation) and total nutrient loads during the twentieth century. The upper and lower delineation of both the higher and the lower zone of potential Z. marina habitats appear to be determined by one or a combination of several of these factors. Environmental changes in one of these factors will therefore influence the borderlines of the zones. The lower zone of Z. marina will be mainly affected by increased turbidity, sediment dynamics, degree of desiccation during low tide and nutrient load. The higher zone will be affected by increases in water and sediment dynamics, desiccation rates and nutrient loads. Potential Z. marina habitats are located above approx. –0.80 m mean sea level (when turbidity remains at the same level as in the early 1990s) in sheltered, undisturbed locations, and preferably where some freshwater influence is present. At locations with a high, near-marine, salinity, the nutrient load has to be low to allow the growth of Z. marina. The sediment should retain enough water during low tide to keep the plants moist. Our results suggest that the return of Z. marina beds within a reasonable time-scale will require not only suitable habitat conditions, but also revegetation measures, as the changes in the environment resulting from the disappearance of Z. marina may impede its recovery, and the natural import of propagules will be unlikely. Furthermore, the lower zone of Z. marina may require a genotype that is no longer found in the Wadden Sea. Received: 26 April 1999 / Received in revised form: 15 October 1999 / Accepted: 16 October 1999     

The Strontium- and Yttrium-Binding Activity of Pectin from the Seagrass Phyllospadix iwatensis Makino, 1931 and Its Modified Derivative

Russian Journal of Marine Biology - Poorly esterified pectin was isolated from the seagrass Phyllospadix iwatensis Makino, 1931 and modified using acidic hydrolysis in 0.5 M HCl. The concentration...     

大叶藻对氮磷营养盐的吸收动力学特征

营养盐是影响海草生长的关键因子, 目前有关海草不同组织对不同形式氮和磷的吸收特征尚不明确。该研究通过利用海草地上和地下组织分隔培养装置, 设置不同的氨态氮、硝态氮和磷酸盐浓度, 探究了大叶藻(Zostera marina)植株及其地上和地下组织对氮磷营养盐的吸收动力学特征。结果显示: (1)大叶藻对氮磷的吸收符合饱和吸收动力学特征, 吸收速率和水体氮磷浓度可用米式方程描述; (2)大叶藻植株对NH₄⁺-N的最大吸收速率(V_max, 52 μmol·g^-1·h^-1)显著高于其对NO₃^--N的V_max (39 μmol·g^-1·h^-1); (3)大叶藻地上组织和地下组织均可吸收氮磷, 但地上组织对氨态氮、硝态氮、磷酸盐的V_max分别为43.1、30.5和15.6 μmol·g^-1·h^-1, 为地下组织的2.6、1.2和6倍。结果表明, 大叶藻对氨态氮的吸收能力高于硝态氮, 且对氮磷的吸收可能主要依赖地上组织(叶片)。结果为查明大叶藻对氮磷的吸收利用机制及评估大叶藻的海洋生态效应提供了理论依据。     

Uptake kinetics of nitrogen and phosphorus by Zostera marina

Aims Nutrient availability is an external factor that affect the growth of seagrasses. However, the demand for and absorption of different forms of nitrogen and phosphorus by different tissues of seagrasses are unclear. In this study, the uptake of nitrogen and phosphorus by Zostera marina was studied to determine the nutrient uptake kinetics. The objectives of this research are to: 1) investigate the absorption characteristics of ammonia nitrogen, nitrate nitrogen and phosphorus in Z. marina; 2) evaluate the differences in absorption between the different forms of nitrogen; and 3) analyse the differences in absorption between the different tissues of Z. marina.Methods Equipment was used to separate the aboveground and belowground tissues of Z. marina. Six concentration levels of ammonia nitrogen, nitrate nitrogen and phosphorus were established to experimentally test the uptake kinetics of nutrients by Z. marina. The nutrient concentrations in different parts of seawater column were measured to determine the nutrient changes and calculate the kinetic characteristics of nutrient uptake.Important findings 1) The absorption of ammonia nitrogen, nitrate nitrogen and phosphorus by Z. marina was consistent with the characteristics of saturated absorption kinetics. The relationship between the absorption rate and the nutrient concentrations in water could be described by the Michaelis-Menten equation. 2) The maximum absorption rate (V_max) of ammonia nitrogen by Z. marina (52 μmol·g^-1·h^-1) was significantly higher than that of nitrate nitrogen (39 μmol·g^-1·h^-1). 3) Both aboveground and belowground tissues of Z. marina could absorb nutrient, but the V_max of leaves (aboveground tissues) for ammonia nitrogen, nitrate nitrogen and phosphorus absorption were 43.1, 30.5 and 15.6 μmol·g^-1·h^-1, respectively, which were 2.6-fold, 1.2-fold and 6-fold higher than the corresponding V_max of belowground tissues. The results show that the absorption capacity of Z. marina for ammonia nitrogen is higher than that for nitrate nitrogen, and the absorption of nitrogen and phosphorus may depend primarily on the aboveground tissues (leaves). The results provide a theoretical basis for the study of the mechanisms of nitrogen and phosphorus uptake and utilization by Z. marina and the evaluation of marine ecological impacts.     

Characterization and seasonal variation of individual flavonoids in Zostera marina and Zostera noltii from Norwegian coastal waters

The flavonoid content in leaves of Zostera marina and the endangered Zostera noltii, including mono- and disulphated flavonoids, from different sample localities were characterized. Seasonal variation of both individual and total flavonoid, as well as rosmarinic acid concentration were revealed. Minor amounts of luteolin 7-(6″-malonyl)glucoside (6) and apigenin7-(6″-malonyl)glucoside (11) were identified in Z. noltii for the first time. The total flavonoid content was found to be higher in Z. noltii than in Z. marina at most of the examined localities, and the qualitative flavonoid content was somewhat different in the two species. The quantitative variation of flavonoids and rosmarinic acid was found to be relatively consistent from year to year in Z. marina during a period of three years. The two species appeared though to have a different flavonoid production in the various seasons at the West coast. While Z. marina had the highest content in young leaves in May or June, with a markedly decrease from June to September and the lowest measured content in February, Z. noltii had the lowest measured flavonoid content in May/June followed by an increase from June to September and the highest measured content during wintertime in February. The observed seasonal differences may be related to the fact that Z. noltii is considered a perennial, thermophilous species, and the increasing flavonoid production during the colder seasons from September to March/April in Norway may serve as a protective function.     

An Effective Method for Collecting and Storing Seeds from Zostera marina (Eelgrass) in the Yellow Sea,China

The coast of the Yellow Sea in China, like many other temperate coastal zones, has been experiencing a dramatic decline in the abundance of seagrass. Intensive efforts have been made to restore seagrass communities along the coast to restore the function of the coastal ecosystem. Transplanting adult Zostera marina shoots is labor‐intensive, time‐consuming, expensive, and detrimental to donor beds; thus, restoring seagrass communities through the use of seeds is highly valued in current, large‐scale restoration trials. In this study, an effective method for collecting, processing, and storing Z. marina seeds was developed. From 2009 to 2013, respectively, 122,000, 421,000, 364,000, 1,041,000, and 1,091,000 seeds were successfully collected. Two‐way analysis of variance (ANOVA) showed the interaction between salinity and temperature significantly affected the cumulative germination rate (CGR) (p < 0.01) during the storage period and the viability (p < 0.01) of seeds after storage. The germination rate after storage was significantly affected by salinity and temperature (p < 0.01). The highest viability (89.8 ± 1.0%) and germination rate (75.6 ± 4.5%) were found among seeds stored at 4°C and a salinity of 44.5 psu for 7 months. The cost for planting 1 ha of sea bottom with Z. marina seeds ranged from $2,613 to $80,900 depending on the seeding density and seed loss during storage. The average cost per Z. marina seed in this study was $0.00586.     

Phytophthora gemini sp. nov., a new species isolated from the halophilic plant Zostera marina in the Netherlands

Eight strains belonging to the Oomycete genus Phytophthora were isolated from Zostera marina (seagrass) in The Netherlands over the past 25 y. Based on morphology, isozymes, temperature-growth relationships and ITS sequences, these strains were found to belong to two different Phytophthora species. Five strains, four of them isolated from rotting seeds and one isolated from decaying plants, could not be assigned to a known species and hence belong to a new species for which we propose the name Phytophthora gemini sp. nov. Three strains were isolated from decaying plants and were identified as Phytophthora inundata, thereby expanding the known habitat range of this species from fresh to brackish-saline areas. The possible role of both Phytophthora species in the decline of Z. marina in The Netherlands and the evolutionary significance of the presence of Phytophthora species in marine environments are discussed.     

Anthesis and seed production in Zostera marina L. (eelgrass) from the chesepeak by

Anthesis and seed production in Zostera marina L. were studied in three areas of the Chesapeake Bay from January to June 1980. Inflorescence primordia with distinguishable anthers and pistils were first observed in February when water temperature was 3°C. Development of the reproductive shoots in the field continued after February as water temperature rose, with the first evidence of pollen release in mid-April (water temperature 14.3°C). Stigmata loss was first observed in samples taken in late April at all locations by as water temperatures averaged above 16°C. Pollination was complete at all locations by 19 May and anthers were no longer present. Few reproduction shoots were found on 3–5 June and seed release was assumed to be complete by this time (water temperature 25°C). The density of flowering shoots ranged from 11 to 19% of the total number of shoots, producing an estimated 8127 seeds m^?2.Comparison of flowering events with other areas along a latitudinal gradient from North Carolina to Canada indicated that reproductive events occurred earlier in the most southern locations and at successively later dates with increasing latitude.     

Antioxidant Activities of a Low Etherified Pectin from the Seagrass Zostera marina

In experiments on male white mice we initiated the induction of peroxidation of lipids by lead acetate, tetrachloromethane, sodium nitrite, or SOVOL (a mixture of polychlorinated biphenyls). Then the animals received intragastral injections of pectin isolated from the seagrass Zostera marina, in the form of a 1% gel, at 100 mg/kg for 2 weeks. It has been found that the low etherified pectin normalizes the level of malonic dialdehyde and the activity of glutathione reductase and glutathione peroxidase in the liver.     

Comparison of Zostera marina and maerl community metabolism

The photosynthetic and repiratory metabolism of Zostera marina and maerl communities was compared, in the same area of the Bay of Brest in March–April, using benthic chambers. P–E curves for both oxygen and carbon were established for bottom irradiances between 0 and 525 μmol m⁻² s⁻¹. An exponential function was fitted to calculate daily production. Community metabolic quotients did not differ for maerl and seagrass beds. Community photosynthetic quotients were significantly higher (1.19) whereas community respiratory quotients were lower (0.70) than 1. Maerl and seagrass bed P–E curves mainly differed by the minimum saturating irradiance (E_k). Net community production was estimated to 26.8 mmol C m⁻² d⁻¹ for Z. marina meadows and 8.6 mmol C m⁻² d⁻¹ for maerl beds. The two communities can, therefore, be considered as autotrophic during the March–April period. Community respiration did not differ between Z. marina meadows and maerl beds, with an average value of 53.8 mmol C m⁻² d⁻¹ during a day. In similar environmental conditions, the production of maerl beds corresponds to approximately one third that of seagrass meadows. The maerl communities, therefore, form productive ecosystems, relevant to temperate coastal ecosystems functioning.     

Grimontia marina sp. nov., a marine bacterium isolated from the Yellow Sea

A novel species belonging to the genus Grimontia is described in this study. A Gram-negative, chemoheterotrophic, obligately aerobic, catalase- and oxidase-positive, motile by a single polar flagellum, and rod-shaped bacterium, designated IMCC5001^T, was isolated from surface seawater of the Yellow Sea. Strain IMCC5001^T grew optimally at 30°C in the presence of 3.5% NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate was related most closely to Grimontia hollisae with a sequence similarity of 95.8%, and formed a robust phyletic lineage with Grimontia hollisae. Differential physiological characteristics between the new strain and Grimontia hollisae KCCM 41680^T and chemotaxonomic characterization including determination of DNA G+C content, fatty acid methyl esters, quinone composition, and polar lipid profiles justified the assignment of strain IMCC5001^T to the genus Grimontia as a novel species. In conclusion, strain IMCC5001^T represents a new species, for which the name Grimontia marina sp. nov. is proposed, with the type strain IMCC5001^T (=KCTC 22666^T =NBRC 105794^T).     

Vitamin B12-independent strains of Methylophaga marina isolated from Red Sea algae

Two strains (KM3 and KM5) of halophilic methylobacteria isolated from Red Sea algae do not require vitamin B12 for growth and can use methanol, methylamine, dimethylamine, trimethylamine, dimethyl sulfide, and fructose as sources of carbon and energy. The cells of these strains are gram-negative motile monotrichous (strain KM3) or peritrichous (strain KM5) rods. The strains are strictly aerobic and require Na+ ions but not growth factors for growth. They are oxidase- and catalase-positive and reduce nitrates to nitrites. Both strains can grow in a temperature range of 4 to 37 degrees C (with optimal growth at 29-34 degrees C), at pH between 5.5 and 8.5 (with optimal growth at pH 7.5-8.0), and in a range of salt concentrations between 0.5 and 15% NaCl (with optimal growth at 5-9% NaCl). The phospholipids of these strains are dominated by phosphatidylethanolamine and phosphatidylglycerol and also include phosphatidylcholine, phosphatidylserine, and cardiolipin. The dominant fatty acids are C(16:1omega7c) and C(16:0). The major ubiquinone is Q8. The cells accumulate ectoin, glutamate, and sucrose as intracellular osmoprotectants. The strains implement the 2-keto-3-deoxy-6-phosphogluconate-dependent variant of the ribulose monophosphate pathway. The G+C content of the DNA is 44.4-44.7 mol %. Analysis of the 16S rRNA genes showed that both strains belong to Gammaproteobacteria and have a high degree of homology (99.4%) to Methylophaga marina ATCC 35842T . Based on the data of polyphasic taxonomy, strains KM3 and KM5 are identified as new strains M. marina KM3 (VKM B-2386) and M. marina KM5 (VKM B-2387). The ability of these strains to produce auxins (indole-3-acetic acid) suggests their metabolic association with marine algae.     

Policy plans and management measures to restore eelgrass (Zostera marina L.) in the Dutch Wadden Sea

The Dutch Wadden Sea has been changed dramatically over the last centuries by human activities like land reclamation and different forms of fishery. This has, amongst other things, led to changes in the number of biological communities. One of the changes was the near extinction of eelgrass (Zostera marina L.) in the Dutch Wadden Sea. The deterioration of the area led to policy plans in the late 1980s that aimed at restoring the original natural communities of which the eelgrass community was one. This paper presents a restoration strategy which contains a selection procedure for suitable transplantation sites. The selection procedure is based on factors such as sediment composition, exposure time, current velocity and wave action. These were combined in a GIS-based map integrating these factors. One important action in the restoration process is to increase the number of freshwater discharge points to meet the requirements of the brackish water community in general and the growing conditions for eelgrass in particular. Received: 27 October 1999 / Received in revised form: 3 February 2000 / Accepted: 3 February 2000     

玻璃化法超低温保存对大叶藻种子活力的影响

通过设置玻璃化法超低温保存的3个关键要素,即冰冻保护液处理、玻璃化溶液脱水时间和冷冻处理,研究了玻璃化法超低温保存对大叶藻种子活力的影响.结果表明:冰冻保护液处理和玻璃化溶液脱水时间对大叶藻种子活力无显著影响;冷冻处理组种子活力显著低于对照组,而冰冻保护液和玻璃化脱水处理对冷冻后种子活力的影响不显著,表明冰冻保护液和玻璃化溶液未对种子起到明显的保护作用;未冰冻保护液处理组玻璃化溶液脱水4h时种子活力显著低于其他脱水时间,而冰冻保护液处理组脱水4h时与其他脱水时间无明显不同,表明较长时间的玻璃化溶液脱水处理需使用冰冻保护液进行预处理.研究结果为超低温保存大叶藻种子提供了参考.     

Effectiveness of pectin extracted from the eelgrass Zostera marina for alleviating lead-induced liver injury

The effects of pectin from the eelgrass Zostera marina on toxic liver injury induced by enteral administration of lead acetate are examined in experiments on rats. The results show that pectin helps to rapidly reduce lead concentration in liver, to decrease lipid peroxidation, and to normalize the levels of total cholesterol and triglycerides in blood serum and liver.     

Rothia marina sp. nov., isolated from an intertidal sediment of the South China Sea

A novel non-sporulating, non-motile, catalase-positive, oxidase-negative, facultatively anaerobic, Gram-positive coccus, designated strain JSM 078151^T, was isolated from an intertidal sediment sample collected from Naozhou Island in the South China Sea, China. Growth was found to occur in the presence of 0–15 % (w/v) NaCl (optimum 0.5–3 % (w/v) NaCl), at pH 6.5–10.5 (optimum pH 7.0–8.0) and at 5–35 °C (optimum 25–30 °C). The peptidoglycan type was determined to be A3a, containing lysine, glutamic acid and alanine. The major cellular fatty acid identified was anteiso-C_15:0 and the predominant menaquinones are MK-7 and MK-8. The polar lipids were found to consist of diphosphatidylglycerol, phosphatidylglycerol, glycolipid and one unidentified phospholipid. The genomic DNA G+C content of strain JSM 078151^T was determined to be 55.2 mol%. A phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain JSM 078151^T should be assigned to the genus Rothia, and was most closely related to Rothia nasimurium CCUG 35957^T (98.3 % sequence similarity), followed by Rothia amarae J18^T (97.5 %) and Rothia terrae L-143^T (97.3 %). A combination of phylogenetic analysis, DNA–DNA relatedness values, phenotypic characteristics and chemotaxonomic data supports the suggestion that strain JSM 078151^T represents a novel species of the genus Rothia, for which the name Rothia marina sp. nov. is proposed. The type strain is JSM 078151^T (= DSM 21080^T = KCTC 19432^T).     

Influence of Pectin from the Seagrass Zostera marina on the Content of DNA and RNA in Rat Hepatocytes Contaminated by Lead

The influence of zosterin-pectin of the seagrass Zostera marina on the content of DNA and RNA in rat hepatocytes under normal conditions and with lead contamination has been studied. It was shown that zosterin increases the share of the high-ploidy (8c) nuclei and the content of the nuclear RNA of the intact animals and, against a background of toxicant action, normalizes the ratio of the ploidy classes and further increases the RNA mass.