Effect of temperature and irradiance on the growth and reproduction of Enteromorpha prolifera J. Ag. （Chlorophycophyta,Chlorophyceae）

Effect of temperature and irradiance on growth and reproduction of Enteromorpha prolifera that bloomed offshore along the Qingdao coast in summer 2008, was studied. It was showed that E. prolifera propagated mainly asexually with specific growth rate （SGR） of 10.47 at 25℃/40 μmol m^-2s^-1. Under this condition, gametes with two flagellate formed and released in 5 days. At the beginning of the development, the unicell gamete divided into two cells with heteropolarity, and then the apical cell developed into thalli primordial cells, whereas the basal cell developed into rhizoid primordial cells. In 8-day culture, the monoplast gamete developed into juvenile germling of 240 μm in length. Unreleased gametes can develop directly within the alga body. E. prolifera could either reproduce through lateral branching or fragmenting except apomixis revealed by Microscopic observation. On aged tissue of E. prolifera, although the degraded pigments partially remained in faded algal filaments, numerous vegetative cells could still divide actively in the algal tissues.     

Effects of diet and body size on phosphorus utilization of Liza haematocheila T. ＆ S.

A 21-d laboratory experiment was conducted to study, the phosphorus （P） utilization of two different diets by redlip mullet Liza haematocheila T. ＆ S. Sand-filtered water in salinity 30 and temperatare 25℃ was used. Twenty-nine fish individuals were divided into three groups： 11 to group 1 （G1） fed on diet 1, 11 to group 2 （G2） fed on diet 2, and 7 to contrast group. Diet 1 was a commercial feed, more valuable in nutrition than diet 2 that similar to natural detritus. The results show the intake phosphorus （IP） of G1 was significantly higher than that of G2, and both increased linearly with body size at a certain amount of diet. The retention phosphorus （RP） in fish of G1 was lower than G2. The relationship between retention phosphorus and body size was positive and stronger in G2. Significant difference in faecal phosphorus （FP） was found between G1 and G2. Body size significantly impacted the excretion phosphorus （EP） in G1 but G2. The loss of intake phosphorus in G1 was 10.83-20.27 mg per g fish weight gain, higher than that in G2 for 6.63-9.56. Of the phosphorus, about 10% was allocated into growth, 50% in faeces, and the rest lost in excretion. The main part of phosphorus was lost in faeces but excretion. The phosphorus budget of the fish could be described as 100IP = 7.40RP ＋ 47.39FP ＋ 36.63EP （Diet 1） or 100IP = 11.93RP ＋ 56.64FP ＋ 21.76EP （Diet 2）.     

Stability analysis and treatment of No. 2 dump of Nanfen iron mine

On the basis of the study on the engineering geological characteristics of No. 2 dump of Nanfen iron mine and the analysis of the failure mode of dump landslide, the stability of the present dump, the stability of the dump 20 years later and the stability of double-bench dump are analyzed. Then, the debris flow risk is evaluated by fuzzy mathematics method. Finally, the comprehensive treatment for the dump is suggested. It is concluded that ① In rainy and snowmelt period, the stability would be decreasing sharply when ground water is not drained out in time; ② Double-bench dumping mode will improve stability of the dump little;③ Debris flow risk is middle danger. The interim debris flow with medium scale may occur. ④ Monitoring, draining and baffling work ought to be well done. ⑤In order to prevent the damage of landslide and debris flow, three measures are adopted, including setting rockfall net, setting the debris flow barrier and removing the residents.     

Morphological Comparison between Chinese Ayu and Japanese Ayu and Establishment of Plecoglossus altivelis chinensis Wu&Shan subsp.nov.

Ayu(Plecoglossus altivelis)belongs to Osmeri-formes,Qsmeridae,Plecoglossus.It is small-sized,one-year living species with high economic value.It can befound in China,Japan,the Peninsula of Korea,andthe north of Vietnam.Nishida(1988)classifiedJapanese native Ayu into two subspecies:nominatesubspecies(Plecoglossus altivelis altivelis)mainlydistributed in the mainland of Japan,the peninsula ofKorea,Taiwan and China mainland;Ryukyus sub-species(Plecoglossus altivelis ryukyuensis)only dis-tr…     

Purification and Refolding of a Novel β-Agarase from Inclusion Body of E. coli

1 Introduction Agarases produced by agar-degrading bacteria are classified into two groups based on their modes of action, namely, α-agarase and β-agarase. They hydrolyze α -1, 3 linkage and β-1, 4 linkage of agarose respectively (Duckworth and Turvey, 1969). Agarases are widely used in food, cosmetic and medical industries for the produc-tion of oligosaccharides from agar (Kobayashi et al., 1997; Yoshizawa et al., 1995). Neoagaro-oligo- saccharides produced by β-agarase inhibit the gro…     

Purification and Refolding of a Novel β-Agarase from Inclusion Body of E. coli

β-agarase AgaB appears to represent a new family of glycoside hydrolase; it is structurally and functionally different from other known agarases. In the present study, AgaB was expressed with a temperature-inducible expression system in E. coli BL21 (DE3) as a fusion protein bearing a C-terminal hexahistidine tag. The protein existed mainly in the form of inclusion body.After being washed and solubilized, AgaB in inclusion body was denatured and purified to electrophoretic purity by immobilized metal affinity chromatography. The purified AgaB was then refolded using a simple pulse dilution method, and the refolded AgaB showed a high specific hydrolysis activity of about 1600 units/mg protein. Forty milligrams of refolded pure protein were obtained from 1L of culture.     

Observation of female gamete （Carpogonia） germination of Porphyra yezoensis and P. oligospermatangia

Several papers have reported that part or whole leafy thallus seemingly consisting of zygotospores can give rise to both blades and conchocelis in the same culture of Porphyra. Study on samples of wild and cultivated Porphyra yezoensis and P. oligospermatangia were conducted to clarify the origination of the young blades in the culture. It is confirmed that single cells on the blade of both species, which normally intermixed with zygotospores, germinated into young blades. TEM and SEM observation has shown that the single cells of Porphyra yezoensis had typical features of female gamete （carpogonia） but archeospore. Therefore, the female gametes are responsible in developing leafy thalli.     

Effects of Temperature and Salinity on Oxygen Consumption and Ammonium Excretion Rate of ♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus Juveniles

The impact of water temperature(24, 27, 30 and 33℃) and salinity(15, 20, 25, 30 and 33) on oxygen consumption(OCR) and ammonium excretion rate(AER) of ♀ Epinephelus fuscoguttatus ×♂ E. lanceolatus hybrid grouper juveniles(9.39 ± 0.07 g) were investigated under the fed and un-fed conditions. The results showed that the OCR and AER were significantly(P < 0.05) affected by temperature and salinity under both fed and un-fed conditions. When temperature was 24–33℃, the OCR and AER of fed hybrid grouper juveniles were 85.68%–129.52% and 125.78%–287.63%, respectively, higher than those of un-fed hybrid grouper juveniles. The O/N ratio, protein use(P_u), Q₁₀(respiration) and Q₁₀(excretion) of fed hybrid grouper juveniles were 14.43–24.01, 28.35% – 48.48%, 1.69 and 3.01, respectively. The O/N ratio, P_u, Q₁₀(respiration), Q₁₀(excretion) of un-fed hybrid grouper juveniles were 20.39 – 31.79, 22.16% – 34.34%, 1.23 and 1.17, respectively. When salinity was 15–33, the OCR and AER of fed hybrid grouper juveniles increased by 87.42% – 116.85% and 215.38% – 353.57%, respectively, over those of un-fed hybrid grouper juveniles. The O/N ratio and P_u of fed hybrid grouper juveniles were 14.48 – 17.78, 39.36% – 49.43%, respectively. The O/N ratio and Pu of un-fed hybrid grouper juveniles were 20.39 – 31.79 and 22.16% – 34.34%, respectively. The specific dynamic action(SDA) of hybrid grouper juveniles was mainly related to protein metabolism. The results had a guiding significance to the large-scale intensive aquaculture of hybrid grouper juveniles.     

Examination of Silicate Limitation of Primary Production in Jiaozhou Bay, China Ⅱ. Critical Value and Time of Silicate Limitation and Satisfaction of the Phytoplankton Growth

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Pyrolytic characteristics and kinetics of the marine green tide macroalgae, Enteromorpha prolifera

The marine macroalgae Enteromorpha prolifera was one of the main algal genera that occurred in the widespread green tides in Qingdao, China, during the summers of 2007, 2008 and 2010. It is thus a plentiful source of biomass and could be used as a biofuel. In this study, the pyrolytic characteristics and kinetics of E. prolifera were investigated using thermogravimetric analysis (TGA) method. Cornstalk and sawdust were used as comparisons. Pyrolytic characteristics were studied using TG-DTG (thermogravimetry-derivative thermogravimetry) curves. Three stages in the pyrolytic process were determined: dehydration, dramatic weight loss and slow weight loss. E. prolifera was pyrolyzed at a lower initial temperature than the two terrestrial biomass forms. The apparent activation energy values for the three types of biomass were calculated and the mechanism functions were determined using 16 different mechanism functions, frequently used in thermal kinetics analysis. Activation energy values varied with mechanism function and the range of activation energy values for E. prolifera, cornstalk, and sawdust were 25-50 kJ/mol, 60-90 kJ/mol and 120-155 kJ/mol, respectively. This indicates that E. prolifera has low thermal stability for pyrolysis and good combustion characteristics.     

Sexual fusion and life history of Scytosiphon lomentaria (Scytosiphonaceae, Phaeophyceae) in Dalian, china

Morphology and life history of a brown alga Scytosiphon lomentaria (Lyngbye) Link (Scytosiphonaceae, Phaeophyceae) were investigated from 2005 to 2009 in the coastal waters of Dalian, China. The erect thalli collected in the field were tubular, hollow, and commonly constricted at intervals. Ascocysts were presented. Plurilocular gametangia, which were positioned in continuous sori on the erect thallus surface, produced biflagellar gametes. Gametophytes were dioecious and gametes were nearly isogamous. Gametes fusion occurred in three types. Type one, female and male gametes fused directly while swimming; type two, female gamete settled first, with which a male one contacted and fused rapidly; type three, while settling adjacently, a male gamete’s entire protoplast moved slowly into the previously settled female one, with only an empty cell membrane left. In culture zygotes developed into crustose sporophytes that formed unilocular sporangia. Biflagellar zoospores developed into erect thalli that formed plurilocular gametangia. The results indicated that a periodical heteromorphic alternation history with haploid gametophyte generation and diploid sporophyte generation exists in S. lomentaria of the Dalian populations.     

The Ulva prolifera genome reveals the mechanism of green tides

The genome of green microalgae has rarely been reported.Ulva prolifera is a green microalga that has received much attention.Despite research articles about U.prolifera in recent years,we know very little about its genome.Therefore,the 87.9-Mb haploid genome(containing 10 311 protein-coding genes)of U.prolifera was studied,and the genome was compared with that of U.mutabilis,which is the only published Ulva species.Results showed that the two species are closely related.A phylogenetic tree was constructed among U.prolifera and other green algae available in GenBank,revealing the evolutionary status of U.prolifera in Chlorophyta.To understand why U.prolifer a could grow rapidly,we identified some genes related to growth,such as those involved in cell division,phosphorylation,and cell proliferation.In addition,genes related to stress resistance were found,which supports the notion that U.prolifera grows vigorously in nature.These results help to characterize green tides from a new perspective and reveal some important insight into the biology of U.prolifera.     

Investigation of the decline of Ulva prolifera in the Subei Shoal and Qingdao based on physiological changes

It has been a scientific consensus that Ulva prolifera green tide that break out annually between May and August in the recent decade off eastern coast of Yellow Sea. To investigate the ecological mechanism of the decline of U. prolifera green tide, we compared the physiological characteristics of U. prolifera samples collected in three stages of the green tide in Subei Shoal north Jiangsu, the initiation point, on May 10(early, the initiation), July 10(middle, the outbreak), and in Taipingjiao, Qingdao on August 10(late, the decline). Compared to the early samples, the middle, and late samples showed a lower chlorophyll content and photosynthetic e fficiency at a higher lipid peroxidation level. The middle and later samples had fewer chloroplasts in the cells of U. prolifera than those in the early samples. In addition, the cells of U. prolifera sampled in the late stage showed ruptured and deformed cell walls. Differences in physiological function were reflected in the growth rate. Both the middle and late U. prolifera samples presented negative growth rates. Correlation analysis results show that the rising temperature was mainly responsible for the local decline of U. prolifera green tide. The high light-intensity that could induce the photoinhibition was also an important factor for the decline. Therefore, U. prolifera population that remained in the Subei Shoal and those that northward drifted to Qingdao experienced the same decline processes: rising temperature and continuous high light conditions in the late phase of green tide reduced the photosynthetic capacity and destroyed the antioxidant system of the thallus, which lead to decrease of biomass. The only difference is that the temperature in the Subei Shoal rose earlier than that in Qingdao; thus, U. prolifera remaining in the Subei Shoal went disappeared first.     

Production of DMS and DMSP in different physiological stages and salinity conditions in two marine algae

Dimethylsulfide(DMS) and dimethylsulfoniopropionate(DMSP) production by Scrippsiella trochoidea and Prorocentrum minimum was investigated to characterize the effects of physiological stage and salinity on DMS and DMSP pools of these two marine phytoplankton species.Axenic laboratory cultures of the two marine algae were tested for DMSP production and its conversion into DMS.The results demonstrated that both algal species could produce DMS,but the average concentration of DMS per cell in S.trochoidea(12.63 fmol/L) was about six times that in P.minimum(2.01 fmol/L).DMS and DMSP concentrations in algal cultures varied significantly at different growth stages,with high release during the late stationary growth phase and the senescent phase.DMS production induced by three salinities(22,28,34) showed that the DMS concentrations per cell in the two algal cultures increased with increasing salinity,which might result from intra-cellular DMSP up-regulation with the change of osmotic stress.Our study specifies the distinctive contributions of different physiological stages of marine phytoplankton on DMSP and DMS production,and clarifies the influence of salinity conditions on the release of DMS and DMSP.As S.trochoidea and P.minimum are harmful algal bloom species with high DMS production,they might play an additional significant role in the sulfur cycle when a red tide occurs.     

Intraspecific genetic analysis, gamete release performance, and growth of Sargassum muticum （Fucales, Phaeophyta） from China

Sargassum muticum is one of the most abundant and conspicuous native macroalgae species on the northern coasts of China. It often forms large-scale seaweed beds in subtidal zones. This investigation was designed to understand the intraspecific genetic relationships of this alga based on samples collected from four northern coastal sites of China, and to evaluate gamete release and growth capacity in laboratory conditions. The nuclear internal transcribed spacer 2 （ITS2） sequences of 16 samples from four locations were identical. Based on cox3 gene and partial rbcLS operon sequences, intraspecific genetic variability was detected with three and two ribotypes, respectively. Temperature, not irradiance, was shown to significantly affect gamete release and fertilization. Elevated temperature and irradiance enhanced the growth of germlings and vegetative branchlets. Maximum growth rate of germlings was detected at 18-24℃and an irradiance of 60-100 μmol photons/（m^2.s）. Under ambient conditions （12-25℃ and 60-125 gmol photons/ （m2.s））, relative growth rate of young branchlets could reach 7.5%/d.     

湛江海域浒苔属Enteromorpha种类的形态与显微结构

用比较解剖学方法观察提江沿海浒苔属（Enteromorpha ）海藻的形态结构,并结合统计分析对其进行 物种鉴定。结果表明,依据藻体分校的有元、数量及分校与主枝直径的大小等形态特征,鉴定的浒苔属j海藻有6种1个变型,分别为缘管浒苔（E. linza）、肠浒苔（ E. intestinalis ）、扁浒苔（ E. compressa ） ,浒苔（E. proliferα）、 条浒苔（E. clathratα）、由浒苔（ E·flexω5α）和肠浒苔宽叶变型（ E. intestinalis f.broadifolium） 0藻体长度由 大到小依次为浒苔、条浒苔、缘管浒苔、肠浒苔、扁浒苔和炀浒苔宽叶变型：细胞呈多角形,藻体的位置不同其细胞大小有所变化,除由浒苔和条浒苔外,其他4种1个变型浒苔的中部细胞最小;所有种类的细胞均有淀粉核,其中肠浒苔、缘管浒苔和扇浒苔仅1个淀粉核,而其他种出现多个淀粉核,尤其条浒苔和曲浒苔数量最多,可达6个以上。定量描述浒苔属6种1个变型的形态特征、内部结构,并发现浒苔属海藻非中空营状的结构特征。     

Observation of female gamete (Carpogonia) germination of Porphyra yezoensis and P. oligospermatangia

Several papers have reported that part or whole leafy thallus seemingly consisting of zygotospores can give rise to both blades and conchocelis in the same culture ofPorphyra. Study on samples of wild and cultivatedPorphyra yezoensis andP. oligospermatangia were conducted to clarify the origination of the young blades in the culture. It is confirmed that single cells on the blade of both species, which normally intermixed with zygotospores, germinated into young blades. TEM and SEM observation has shown that the single cells ofPorphyra yezoensis had typical features of female gamete (carpogonia) but archeospore. Therefore, the female gametes are responsible in developing leafy thalli. This project was sponsored by the NSFC (No. C-0205-05-39770593)