Anticoagulant properties of a sulfated galactan preparation from a marine green alga, Codium cylindricum

An anticoagulant was isolated from a marine green alga, Codium cylindricum. The anticoagulant was composed mainly of galactose with a small amount of glucose, and was highly sulfated (13.1% as SO3Na). The anticoagulant properties of the purified anticoagulant were compared with that of heparin by assays of activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) using normal human plasma. The anticoagulant showed similar activities with heparin, however, weaker than heparin. On the other hand, the anticoagulant did not affect PT even at the concentration at which APTT and TT were strongly prolonged. The anticoagulant did not potentiate antithrombin III (AT III) and heparin cofactor II (HC II), thus the anticoagulant mechanism would be different from that of other anticoagulants isolated so far from the genus Codium.     

DNA sequencing and anatomy demonstrate that Pacific Codium simulans is a genetically variable species found in the floras of Bermuda and Florida

When DNA sequences from Bermuda plants described as Codium isthmocladum ssp. clavatum and a recent collection from Florida originally thought to be C. decorticatum were analyzed, they were found to be a genetic match to the Pacific Mexican species C. simulans. Historical voucher collections assigned to C. isthmocladum ssp. clavatum show that this Pacific lineage has been present in Bermuda (Atlantic) waters for over a century, thus precluding a very recent introduction from the Pacific. We hypothesize that C. simulans may have hitched a ride on the ballast rocks of early commercial ships plying their trade between the Pacific and Atlantic Oceans.     

Grazing of the invasive alga Codium fragile ssp. tomentosoides by the common periwinkle Littorina littorea: Effects of thallus size, age and condition

We examined the potential of herbivory by the common periwinkle Littorina littorea to limit recruitment and vegetative re-growth of the invasive green alga Codium fragile ssp. tomentosoides in a series of manipulative field experiments in tidepools on a wave-exposed rocky shore in Nova Scotia, Canada. Snails were excluded or included from circular plots (14 to 20 cm diameter) with cages to compare growth and survival of C. fragile against procedural (partial cages) or natural (uncaged) control plots. Our results show that L. littorea may restrict growth and survival of C. fragile by grazing new recruits (< 2 cm thallus length), fronds of adult thalli that are bleached and necrotic, and residual holdfasts (< 2 mm thickness) of detached thalli (artificially severed to mimic wave dislodgement). Once recruits grow beyond a critical size (~ 3 cm), or damaged tissues or holdfasts regenerate, grazing of C. fragile by L. littorea appears to be limited and ineffectual. Our experimental results corroborate correlative evidence from previous studies that herbivory by L. littorea limits the abundance of C. fragile in tidepools on the Atlantic coast of Nova Scotia, particularly pools in the high intertidal zone where these snails are abundant. Lower on the shore, littorinid grazing and physical stressors that render algae more vulnerable to grazers (e.g. UV radiation and freezing) are less intensive, and probably have less of a regulatory effect on populations of C. fragile.     

管藻目绿藻刺松藻PSⅡ捕光复合物多肽结构分析

对管藻目绿藻刺松藻 (Codiumfragile (Sur.)Hariot.)的 4种主要的捕光复合物LHCP1-3 和LHCP3′的多肽组成和相互关系进行了研究。LHCP1在SDS_PAGE中主要呈现 34 .4、31.5、2 9.5、2 8.2和 2 6 .5kD 5种多肽 ,其中 34 .4和31.5kD多肽是高等植物所没有的 ;LHCP3 含有LHCP1中除了 34 .4kD多肽以外的其他 4种多肽 ,而LHCP3′只含有2 8.2和 2 6 .5kD两种多肽。若LHCP1不经处理直接进行SDS_PAGE ,发现较易从LHCP1上脱落的是 34 .4、2 8.2和2 6 .5kD多肽 ,这表明它们可能位于较外侧 ,而 31.5和 2 9.5kD多肽则靠近核心 ;2 8和 2 6kD两种多肽常出现在刺松藻的中心复合物CPa中 ,可能是与CCⅡ结合最为紧密的LHCⅡ多肽。根据上述结果提出了 1个LHCP1多肽结构关系示意图     

Anticoagulant properties of a sulfated galactan preparation from a marine green alga, Codium cylindricum

An anticoagulant was isolated from a marine green alga, Codium cylindricum. The anticoagulant was composed mainly of galactose with a small amount of glucose, and was highly sulfated (13.1% as SO Na). The anticoagulant properties of the purified anticoagulant were compared with that of heparin by assays of activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) using normal human plasma. The anticoagulant showed similar activities with heparin, however, weaker than heparin. On the other hand, the anticoagulant did not affect PT even at the concentration at which APTT and TT were strongly prolonged. The anticoagulant did not potentiate antithrombin III (AT III) and heparin cofactor II (HC II), thus the anticoagulant mechanism would be different from that of other anticoagulants isolated so far from the genus Codium.     

Immunostimulating effects of a sulfated galactan from Codium fragile

A pyruvylated sulfated galactan from Codium fragile is a highly ramified polysaccharide consisting of 3-linked, 3,6-linked, and non-reducing terminal d-galactose with pyruvate and sulfate groups; the glycan exerts anti-herpes simplex virus type 2 effects in vitro and in vivo. This particular polysaccharide was found to stimulate the production of nitric oxide by inducing iNOS at the mRNA and protein levels. In addition, the polysaccharide also induced several cytokine mRNA expressions such as IL-1β, IL-6, IL-10 and TNF-α. Therefore, it appears that the sulfated galactan might possess the immunostimulating effects via activation of macrophages.     

管藻目绿藻刺松藻PSⅡ捕光复合物多肽结构分析

对管藻目绿藻刺松藻(Codium fragile (Sur.) Hariot.)的4种主要的捕光复合物LHCP1-3和LHCP3′的多肽组成和相互关系进行了研究.LHCP1在SDS-PAGE中主要呈现34.4、31.5、29.5、28.2和26.5 kD 5种多肽,其中34.4和31.5 kD多肽是高等植物所没有的;LHCP3含有LHCP1中除了34.4 kD多肽以外的其他4种多肽,而LHCP3′只含有28.2和26.5 kD两种多肽.若LHCP1不经处理直接进行SDS-PAGE,发现较易从LHCP1上脱落的是34.4、28.2和26.5 kD多肽,这表明它们可能位于较外侧,而31.5和29.5 kD多肽则靠近核心;28和26 kD两种多肽常出现在刺松藻的中心复合物CPa中,可能是与CCⅡ结合最为紧密的LHCⅡ多肽.根据上述结果提出了1个LHCP1多肽结构关系示意图.     

Effects of native and invasive macroalgal canopies on composition and abundance of mobile benthic macrofauna and turf-forming algae

We examined the effects of native kelps, Laminaria longicruris de la Pylaie and L. digitata (Hudson) Lamouroux, and of the invasive alga, Codium fragile ssp. tomentosoides (Van Goor) Silva, on the composition and abundance of mobile benthic macrofauna and of turf algae by measuring the response of these assemblages to experimental removal of the respective macroalgal canopy. From June 2003 to November 2004, we censused macrofauna and measured canopy cover within 4 × 10 m strips of alternating Canopy Intact (control) and Canopy Removed treatments in both a Codium- and a Laminaria-dominated habitat in the rocky subtidal zone of a semi-protected embayment on the Atlantic coast of Nova Scotia, Canada. Macroalgal canopy cover fluctuated seasonally, peaking in September/October (69% cover in 2003; 55% cover in 2004) for Codium and in May 2004 (70% cover) for kelps, and with both canopy types reaching a winter minimum in January 2004 (22 and 28% cover, respectively). In both Codium and Laminaria habitats, significant effects of canopy removal on the overall macrofaunal assemblage were evident only during periods in which canopy cover in the Canopy Intact treatment was ≥ 50%. In the Codium habitat, 4 out of 11 characteristic taxa were more abundant in the Canopy Intact treatment, where taxonomic diversity also was higher. In contrast, 4 out of 11 characteristic taxa in the Laminaria habitat were more abundant in the Canopy Removed treatment and diversity was similar between treatments. Turf algae were sampled in November 2004 and, despite between-treatment differences in the light regime, there was no significant effect of canopy removal. Our results indicate that selection of algal habitats by mobile macrofauna is likely determined by the different shelter and foraging opportunities offered by these morphologically dissimilar ecosystem engineers.