Structure of reproductive apparatus of Gracilaria/ Gracilariopsis lemaneiformis (Gracilariaceae, Rhodophyta)

Reproductive apparatus of Gracilaria/Gracilariopsis lemaneiformis collected from Qingdao city were studied with a light and a transmission electron microscope. The special superficial arrangement of spermatangium for this species was clearly observed, and the ultrastructure of spermatangial development revealed the similar cytodynamic pattern followed by all the Gracilariaceae members developed from spermatangial mother cells to spermatangium. The female reproductive apparatus before fertilization was also observed and trichogyne was found protruding above the cortex, contrary to the earlier reports. Tetrasporangium was formed by an outer cortical cell and the tetraspores became spherical and expended after being released. Supported by the National Natural Sciences Foundation of China (Grant No. 40606034) and the National High-Tech Research and Development Program of China (Grant No. 2006AA10A413)     

Optimization of the yield and quality of agar from Gracilariopsis lemaneiformis (Gracilariales) from the Gulf of California using an alkaline treatment

The effect of several alkali treatments on the yield, gel strength, rheology, and chemical characteristics (quality) of the agar obtained from Gracilariopsis lemaneiformis from the Gulf of California was analyzed using different alkali concentrations, temperatures and treatment times. In the first stage of the experiment, all treatments lasted 60 min and the NaOH concentrations (2.5, 3.0, 4.0, 5.0, 6.0%) and temperature (80, 90, 100°C) varied. At constant time, temperature played the predominant role, promoting an increase in agar gel strength. Based on the best treatment conditions found (4% and 5% NaOH, and 90°C and 100°C temperature), in the second stage different treatment times (15, 30, 60, 90, 120 min) were used. Since agar yields were not significantly different among temperatures and times, the optimal conditions to obtain best quality agar were those providing the highest gel strength. Treatment time played an important role in increasing gel strength. Maximum gel strength (Nikan, 954 g cm⁻²) was obtained with 5% NaOH at 100°C after 90 min of treatment, though these conditions resulted in an agar yield reduction of 25.5% relative to native agar. This treatment proved to efficiently yield G. lemaneiformis agar that will meet the commercial quality requirements regarding gel strength, 3,6 anhydrogalactose and sulfate content, as well as rheology and hysteresis. Enrique Hernández-Garibay holds a CONACyT scholarship.     

Cloning and characterization of two types of ubiquitin genes from Gracilariopsis lemaneiformis (Gracilariales, Rhodophyta)

Two types of ubiquitin genes were isolated from the marine red alga Gracilaria lemaneiformis: a ubiquitin-52 amino acid fusion protein gene, and a 6-unit polyubiquitin gene. Alignment of polyubiquitins among three red algae (Gracilaria lemaneiformis, Gracilaria verrucosa, Aglaothamnion neglectum) and other species revealed that there were six ubiquitin repeats in all three red algae polyubiquitins, and that glutamine was the final amino acid residue in the terminal repeat of the polyprotein in the two Gracilaria sequences. Southern blot analysis revealed that both genes were encoded by low-copy number genes. Semi-quantitative RT-PCR was performed to investigate the expression of these two genes in two phases of G. lemaneiformis. The result revealed that the monoubiquitin was phase-relative, and upregulated in tetrasporophytes compared with female gametophytes. The polyubiquitin gene was expressed at similar levels in both phases.     

龙须菜中溴过氧化物酶的分离纯化及酶学性质分析

对中国北方海域江蓠属养殖龙须菜(Gracilaria lemaneiformis)进行了溴过氧化物酶分离纯化及性质的研究。粗提液中酶催化检测反应不稳定, 活力单位较低或无; 经DEAE cellulose 52离子交换层析, 去除了结构多糖及藻胆蛋白, 酶催化反应稳定, 得到比活力为2.8的电泳纯溴过氧化物酶。对纯化溴过氧化物酶性质研究表明: 该溴过氧化物酶为单体酶, 分子量约66 kD, 溴化单氯双甲酮时的最适pH值为6.0, 在40°C以下和pH 3.0~9.0之间有很好的稳定性。钒酸盐可提高该溴过氧化物酶的催化活性, 而Fe2+、Fe3+、Cu2+、Zn2+和EDTA等化合物对其有较显著的抑制作用。反应动力学实验表明, 该酶对Br-、H2O2的Km分别为53.5 mmol/L和38 mmol/L。     

龙须菜中溴过氧化物酶的分离纯化及酶学性质分析

对中国北方海域江蓠属养殖龙须菜(Gracilaria lemaneiformis)进行了溴过氧化物酶分离纯化及性质的研究。粗提液中酶催化检测反应不稳定, 活力单位较低或无; 经DEAE cellulose 52离子交换层析, 去除了结构多糖及藻胆蛋白, 酶催化反应稳定, 得到比活力为2.8的电泳纯溴过氧化物酶。对纯化溴过氧化物酶性质研究表明: 该溴过氧化物酶为单体酶, 分子量约66 kD, 溴化单氯双甲酮时的最适pH值为6.0, 在40°C以下和pH 3.0~9.0之间有很好的稳定性。钒酸盐可提高该溴过氧化物酶的催化活性, 而Fe2+、Fe3+、Cu2+、Zn2+和EDTA等化合物对其有较显著的抑制作用。反应动力学实验表明, 该酶对Br-、H2O2的Km分别为53.5 mmol/L和38 mmol/L。     

Seasonal changes in the chemical and gelling characteristics of agar from Gracilaria verrucosa collected in Turkey

The chemical and gelling properties of agar from G. verrucosa collected from Izmit bay in Turkey at different months of the year were studied. Purification of agar was performed by using amylase treatment and isopropyl alcohol precipitation. The phycocolloid content was between 24.0–43.0% of the algal dry weight and was maximum in summer collected algae. Relative total sulfate and 3,6-anhydrogalactose content in the agar were determined from the ratios of infrared spectroscopy band intensities at 1250/2920 cm^–1 and 930/2920 cm^–1, respectively. 3,6-anhydrogalactose and sulfate contents were the highest in agar from algae collected from June until November and January until July, respectively. The gel strength of native agar were the highest from in autumn collected algae and increased to about 1250 N m^–2 after alkali treatment. Thus, this study demonstrated that G. verrucosa from Turkey produces an agar with optimal chemical and gelling properties after alkali-treatment in fall and winter collected algae and may be used for industrial agar production.     

Effects of season on the yield and quality of agar from Gracilaria species (Gracilariaceae, Rhodophyta)

The effect of season on yield and physical properties of agars extracted from Gracia gracilis and G. bursa-pastoris were determined. The agar yield from G. gracilis was maximum during spring (30%) and minimum during autumn (19%). In G. bursa-pastoris, the agar yield was greatest in summer (36%) and lowest in winter (23%). Agar yield from G. bursa-pastoris was positively correlated with temperature (r=0.94; P<0.01) and salinity (r=0.97; P<0.01) and negatively with nitrogen content (r=−0.93; P<0.01). Agar gel strengths fluctuated from 229 to 828 g cm⁻² and 23 to 168 g cm⁻² for G. gracilis and G. bursa-pastoris, respectively. The gelling temperature showed significant seasonal variation for both species. Chemical analysis of agar from the two seaweeds indicated variation in 3,6-anhydrogalactose and sulfate content (P<0.01). Furthermore, there was an inverse correlation between the two chemical variables. In general, agar extracted from G. gracilis possessed better qualities than agar extracted from G. bursa-pastoris and can be considered a candidate for industrial use.     

龙须菜多糖提取工艺优化及其体外免疫活性研究

本文对龙须菜（Gracilaria lemaneiformis）50℃下水提的粗多糖进行冻融,将其分成胶体和非胶体部分,比较了他们的溶出率、多糖含量、蛋白含量和体外免疫活性,并在此基础上应用正交实验对非胶体粗多糖的提取工艺进行了优化。结果表明,胶体部分的溶出率和多糖含量均显著高于非胶体部分,但是非胶体部分的免疫活性极显著高于胶体部分（P〈0．01）;尽管提取次数对溶出率有着较大的影响,但提取次数、料水比和提取时间对非胶体粗多糖的多糖含量、蛋白含量、免疫活性均无显著影响,综合正交实验结果和实际生产中的能耗因素,确定50℃条件下的最佳提取工艺为：料水比1：40（质量比）,提取2次,每次浸提3h。     

Comparison of three gracilarioids: growth rate, agar content and quality

Three gracilarioid species, Gracilariopsis bailiniae and Gracilaria tenuistipitata from Vietnam and Gracilaria gracilis from Russia, were studied in order to determine whether Gracilaria gracilis might be a superior species for cultivation in brackish-water ponds for agar production compared with the Vietnamese species. The effects of different salinity levels on the growth rate and agar production as well as agar properties of three gracilarioid species were compared in controlled laboratory experiments. Gracilaria tenuistipitata and G. gracilis were tolerant to low salinity (∼10‰), whereas Gp. bailiniae died under these conditions. G. tenuistipitata showed superior growth among the three species examined. Gracilaria gracilis had the highest agar content [36.8–46.6% dry weight (dw)]. Agar yield from Vietnamese gracilarioids did not exceed 30% dw. Gel strength of native agar from Gracilaria gracilis was two-fold higher that from Vietnamese species (278 g cm⁻² vs 130 g cm⁻²). Alkali pretreatment increased gel strength significantly for Gracilaria gracilis (1.4-fold), and G. tenuistipitata and Gp. bailiniae (2.3-fold) compared with native agar. The results suggest that Gracilaria gracilis may be a suitable species for production of reasonably good quality agar.     

Chemical composition of agars from a newly reported Japanese agarophyte,Gracilariopsis lemaneiformis

The chemical composition of agars from Gracilariopsis lemaneiformis, newly reported from Japan, was investigated. Native agars were isolated by a sequential extraction of plants in water at 22 °C and 100 °C, and in boiling 20, 40 and 60° ethanol. Agars in each extract were analyzed by chemical methods, ¹H, ¹³C NMR; and IR spectroscopy. The highest yield of agar (total carbohydrate) was obtained from the 40° ethanol extract (55°). Highest sulfate content was attained in non-alkali treated agars extracted with hot water (4.81°, DS 0.2). The 3,6-anhydrogalactose content was highest in the 40° ethanol extract (36.1° in non-alkali treatment, 40.3° in alkali treatment). The highest methoxyl content (6.51°, DS 0.66) was obtained in the 60° ethanol extract. The G. lemaneiformis agar is composed of the biological precursor to agarobiose repeating units and agarobiose containing 6-O-methyl agarobiose and a small amount of 2-O-methyl-α-l-galactopyranose residues. Alkali treatment improved the chemical quality of the agar fractions, which was comparable with Japanese commercial agar and agarose.     

Optimisation of RNA extraction from Gracilaria changii (Gracilariales, Rhodophyta)

RNA extraction from seaweed tissues is problematic due to the presence of polysaccharides and polyphenolic compounds upon cell disruption. Besides, a successful RNA isolation from seaweed tissues can sometimes be strain- and species-specific. Four different methods were used to extract RNA from Gracilaria changii (Gracilariales, Rhodophyta), collected from the mangrove area at Morib, Selangor, Malaysia. An optimised and modified total RNA extraction method was developed for this recalcitrant species. The use of sand in tissue grinding, and the incorporation of phenol extraction at the initial stage resulted in the highest RNA yield (0.65–1.14 g g^–1 fresh weight) with high quality (A_260:280 ratio 1.80–2.05). The RNA obtained is suitable for cDNA synthesis and future functional genomic studies.     

龙须菜多糖脱硫酸化及免疫活性研究

考察了Miller等和Nagasawa等报道的脱硫酸方法对龙须菜多糖硫酸基脱除效果,并比较了脱硫酸前后多糖的免疫活性变化。实验结果显示,采用Miller等报道的方法时,以草酸作为催化剂对硫酸基脱除效果最好,脱除率达到71.4%,远好于其他种类酸催化,但多糖回收率却只有36.4%;采用Nagasawa等报道的方法时,向二甲基亚砜溶液中加入10%甲醇比加入2%吡啶或2%吡啶+2%三甲基氯硅烷具有更好的脱硫酸基效果,硫酸基脱除率达到72.9%,回收率48.9%,是本次实验中效果最好的。免疫活性实验表明,当降低龙须菜多糖硫酸基含量时,免疫活性相应降低。     

Comparison of growth rate in culture,dry matter content,agar content and agar quality of two New Zealand red seaweeds,Gracilaria chilensis Bird,McLachlanet Oliveira andGracilaria truncata Kraft

Plant growth rates and agar characteristics were compared for two agarophytes,Gracilaria chilensis (Gracilariales, Rhodophyta) andG. truncata, so that the suitability ofG. truncata for mariculture could be assessed.G. chilensis plants grew steadily in the laboratory culture system at rates of 5–8% day^-1 (mean Relative Growth Rate) throughout the 6 week experimental period, with no decline in health.G. truncata plants grew at rates of 2–4% day^-1 for 5 weeks, but during the sixth week their apical tips became necrotic and growth rates fell to zero. There was no significant difference in the dry matter content (as a percentage of their wet weight) between the two species ofGracilaria, with values falling in the range of 16–19%. Slightly higher agar yields were obtained from alkali-treatedG. chilensis (17–20% dry matter) than from untreatedG. truncata (16–18%) although the agar fromG. truncata formed softer gels from which it was more difficult to recover. The gel strength of untreated agar extracted fromG. chilensis was very low (ca. 100 g cm^-2 for a 1% gel) but when an alkali treatment step was included in the extraction process, it increased to 520 g cm^-2 for a 1% gel. Contrary to an earlier report, untreatedG. truncata agar also had a very low gel strength (ca. 100 g cm^-2 for a 1.5% gel), but it rose to only 167 g cm^-2 after alkaline treatment.     

两种抗生素对龙须菜的光合生理效应

探讨了不同浓度的两种抗生素(氯霉素和青霉素G钠)对龙须菜(Gracilaria lemaneiformis)生长、光合作用、呼吸作用、色素含量以及可溶性蛋白含量等生理特性的影响。结果表明:龙须菜的生长受到两种抗生素的影响,但是氯霉素的影响要比青霉素G钠的影响大的多。在氯霉素处理的过程中,光合作用、有效光化学效率(Yield)、藻红藻蓝蛋白以及可溶性蛋白含量都随着氯霉素浓度的升高而显著下降,但是呼吸作用速率由于氯霉素的处理而升高;此外光合色素含量不受氯霉素的影响。在青霉素G钠的处理中,光合作用、有效光化学效率随着青霉素G钠的升高而下降,龙须菜叶绿素a与类胡萝卜素含量随着青霉素G钠浓度的升高而具有升高的趋势,但藻红蛋白、藻蓝蛋白以及可溶性蛋白在各处理组之间均没有表现出一定趋势。这些结果说明,氯霉素对生长的影响主要是光合作用速率的下降,以及有关蛋白合成下降引起,而青霉素G钠对生长的影响可能原因是呼吸作用速率的增加引起。由于龙须菜对氯霉素的敏感性比对青霉素G钠的敏感性更强,氯霉素在基因工程的育种中可能更适合作为选择压力。     

Growth,pigments, UV-absorbing compounds and agar yield of the economic red seaweed <Emphasis Type="Italic">Gracilaria lemaneiformis</Emphasis> (Rhodophyta) grown at different depths in the coastal waters of the South China Sea

The economic red alga, Gracilaria lemaneiformis Bory, was grown at different depths in the coastal waters of the South China Sea, and its growth, pigments, ultra-violet (UV)-absorbing compounds and agar yield were investigated in order to see the impacts of depth change. Gracilaria lemaneiformis grew slower at greater depths in March, while the highest relative growth rate (RGR) was found at about 1.0 m depth in April, about 9% higher than that at surface water (0.5 m below the surface). The RGR increased with the increasing daily photosynthetically active radiation (PAR) dose received by the thalli at different depths. The contents of phycoerythrin and chlorophyll a increased, while that of UV-absorbing compounds (UVAC, absorption peak at 325 nm) decreased with increased depth. The highest levels of the UVAC in the thalli grown in surface seawater played a protective role against solar UV radiation (280–400 nm). The content of UVAC declined at deeper depths and under indoor low PAR. The agar yield of the thalli increased with the increasing depths, with the highest content found at 3.5 m depth.     

Growth characters and photosynthetic capacity of <Emphasis Type="BoldItalic">Gracilaria lemaneiformis</Emphasis> as a biofilter in a shellfish farming area in Sanggou Bay,China

Experiments on growth characters and ecological functions of the macroalgae Gracilaria lemaneiformis, collected from south China, were conducted in polyculture areas of kelp and filter-feeding bivalve in Sanggou Bay in Weihai City, Shandong, in north China from May 2002 to May 2003. The results of 116 days cultivation showed that the average wet weight of alga increased 89 times from 0.1 to 8.9 kg rope⁻¹, with an average specific growth rate (based on wet weight) of 3.95% per day. The most favorable water layer for its growth was 1.0–1.8 m below the surface in July and August, with an average specific growth rate of 8.2% per day in 30-day experiments. Photosynthetic activity changed seasonally, with an average of 7.3 mg O₂ g dw⁻¹ h⁻¹. The maximum rate (14.4 mg O₂ g dw⁻¹ h⁻¹) was recorded in July, or 19.3 mg CO₂ g dw⁻¹ h⁻¹, while the minimum (0.40 mg CO₂ g dw⁻¹ h⁻¹) was in April. This study indicated that the culture of G. lemaneiformis is an effective way to improve water quality where scallops are cultivated intensively.     

Effect of salinity and pH on growth and agar yield of Gracilaria tenuistipitata var. liui in laboratory and outdoor cultivation

Acclimation responses of the red alga Gracilaria tenuistipitata var. liui collected on the northwest coast of Philippines were determined in laboratory setups and outdoor cultivation tanks in Haifa, Israel. Growth under laboratory conditions was influenced by all three variables studied, namely, temperature (20 or 30 ^°C), salinity (20, 30 or39‰) and seawater pH (6.5, 7.0, 8.0 or ≥ 9.0). In 250 mL flasks lacking pH control growth was influenced by temperature only at 20 ‰, whereas at 39 ‰, growth rates were similar at 20 or 30 ^°C. In 500 mL cylinders in which pH was controlled, growth rates were significantly different at a pH of 6.5 and 7.0 for all salinities, with maximal rates occurring in 39 ‰. At pH 8.0, and above, growth rates between salinities were similar and reduced to approximately 50% at a pH of 9.0 compared to rates at a pH of 6.5. Photosynthesis responses generally resembled growth responses both, in 250 mL and 500 mL cultures. In 40-L outdoor tanks, weekly growth and agar yields were apparently enhanced by increasing light intensities (up to full sunlight) and nutrient concentrations (up to 0.2 mM PO₃ ^2- and 2.0 mM NH₄ ⁺), and rates averaged four times higher than rates determined in the smaller flask cultures. This study shows broad salinity tolerance of G. tenuistipitata var. liui and its ability to sustain growth rates that are among the highest measured for Gracilaria spp. in outdoor cultures. This revised version was published online in August 2006 with corrections to the Cover Date.     

Optimization of culture conditions and scale-up to plant scales for teicoplanin production by <Emphasis Type="Italic">Actinoplanes teichomyceticus</Emphasis>

This report describes the optimization of culture conditions for teicoplanin production by Actinoplanes teichomyceticus KCCM-10601, an identified high-teicoplanin-producing strain (US 2006/0134757 A1). Among the conditions tested, temperature, pH, and the dissolved oxygen tension (DOT) were key factors affecting teicoplanin production. When the temperature, pH, and DOT were controlled at 34 degrees C, 7.0 and 20-30%, respectively, a dry-cell weight of 42.8 g l(-1) and a teicoplanin production of 2.9 g l(-1) were obtained after 120 h of batch culture, corresponding to a specific teicoplanin content of 67.8 mg g-DCW(-1). Teicoplanin production was scaled-up from a laboratory scale (7-l fermenter) to a pilot scale (300 l) and a plant scale (5,000 l) using the impeller tip velocity (V tip) as a scale-up parameter. Teicoplanin production at the laboratory scale was similar to those at the pilot and plant scales. This is the highest report of pilot- and plant-scale production of teicoplanin.