Fermentation optimization and enzyme characterization of a new ι-Carrageenase from Pseudoalteromonas carrageenovora ASY5

Background: A new ι-carrageenase-producing strain was screened from mangroves and authenticated as Pseudoalteromonas carrageenovora ASY5 in our laboratory. The potential application of this new strain was evaluated. Results: Medium compositions and culturing conditions in shaking flask fermentation were firstly optimized by single-factor experiment. ι-Carrageenase activity increased from 0.34 U/mL to 1.08 U/mL after test optimization. Optimal fermentation conditions were 20°C, pH 7.0, incubation time of 40 h, 15 g/L NaCl, 1.5% (w/v) yeast extract as nitrogen source, and 0.9% (w/v) ι-carrageenan as carbon source. Then, the crude ι-carrageenase was characterized. The optimum temperature and pH of the ι-carrageenase were 40°C and 8.0, respectively. The enzymatic activity at 35­40°C for 45 min retained more than 40% of the maximum activity. Meanwhile, The ι-carrageenase was inhibited by the addition of 1 mmol/L Cd2+ and Fe3+ but increased by the addition of 1 mmol/L Ag+, Ba2+, Ca2+, Co2+, Mn2+, Zn2+, Fe2+, and Al3+. The structure of oligosaccharides derived from ι-carrageenan was detected using electrospray ionization mass spectrometry (ESI-MS). The ι-carrageenase degraded ι-carrageenan, yielding disaccharides and tetrasaccharides as main products. Conclusions: The discovery and study of new ι-carrageenases are beneficial not only for the production of ι-carrageenan oligosaccharides but also for the further utilization in industrial production.

Anticoagulant and antibacterial activities of polysaccharides of red algae Corallina collected from Lebanese coast.

In this work, we studied another species of red algae, Corallina, growing on the Lebanese coast of Batroun. The analysis of trace elements showed that Corallina was rich in K, Ca, Mg, Na, Si, Sr, P and Fe. Corallina was composed of 70.81% of saturated fatty acids, 25.54% of monounsaturated fatty acids and 3.65% of polyunsaturated fatty acids with palmitic acid as the main component. Moreover, the total yield of sulfated galactans and carrageenan was 2.5% and 10%, respectively. Both extracts exhibited anticoagulant effect but sulfated galactans were less potent than carrageenan. Sulfated galactans possessed inhibitory activity as well as bactericidal activity against all Gram-positive strains tested (Enterococcus faecalis ATCC 29212 and Staphylococcus epidermidis CIP 444). But, carrageenan was only able to inhibit the growth of S. epidermidis with a minimal inhibitory concentration (MIC) of 0.325 mg/mL. Furthermore, infrared spectroscopy (IR) revealed that the isolated carrageenan was of Lambda-type. Corallina could therefore be considered as a potential source of bioactive molecules that may be useful for the development of new pharmaceutical agents.

Polysaccharides of the red algae 'Pterocladia' growing on the Lebanese coast: Isolation, structural features with antioxidant and anticoagulant activities.

In addition to their high nutritional value, red algae are of great interest as a source of therapeutic substances. However, despite their abundance on the Lebanese coast red algae have never been studied before. Therefore, we attempted to study among the available biomass one of the species of red algae growing on the Lebanese coast “Pterocladia”. We performed the extraction of trace elements, fatty acids, sulfated galactans and watersoluble polysaccharides of the phycocolloids family (carrageenans) whose physicochemical gelling or stabilizing effects attract many industrial sectors. The analysis of trace elements shows large amounts of potassium, calcium, silicon and iron. Moreover, Pterocladia appears to be rich in saturated fatty acids (69%) with palmitic acid as major fatty acid and 31% of monounsaturated fatty acids. The extraction yields were 2.7% for sulfated galactans and 11.5% for carrageenan. In order to elucidate their structures, H¹ NMR spectroscopy was performed as well as Infra-Red spectroscopy which allowed us to reveal their functional groups. A study of the antioxidant effect by the electrolysis method showed a greater effect for sulfated galactans. Furthermore, the study of the anticoagulant effect by APTT test, activated partial thromboplastin time, showed more pronounced anticoagulant power of sulfated galactans. The results of the present study confirmed the potential use of the red algae Pterocladia as a source of active known molecules.

Biological activities of the sulfated polysaccharide from the vascular plant Halodule wrightii

A sulfated polysaccharide (SPSG) was successfully isolated from seagrass Halodule wrightii Asch., Cymodoceaceae, and its antioxidant and anticoagulant activities were investigated. The data presented here showed that the SPSG is a 11 kDa sulfated heterogalactan with a sulfatation degree of 20.63 percent and it also contains glucose and xylose. SPSG antioxidant activities were evaluated using several in vitro assays and the anticoagulant activity was evaluated by aPTT and PT tests. These assays suggested that the SPSG possessed remarkable antioxidant properties in different in vitro assays and an outstanding anticoagulant activity 2.5-fold higher than that of heparin Clexane® in the aPTT test. This data represents the first reported on the sulfated polysaccharide biological activities from seagrass. These results indicate that SPSG can be considered in the future as a drug utilized in treating diseases from these systems.

Anticoagulant properties of a crude sulfated polysaccharide from the red marine alga Halymenia floresia (Clemente) C Agardh / Propriedades anticoagulantes de um polissacarídeo sulfatado bruto da alga marinha vermelha Halymenia floresia (Clemente) C Agardh

Alternative sources of anticoagulants have arisen as a result of the increasing demand for safer anticoagulant clinical therapy, and the sulfated polysaccharides of seaweeds have gained attention in biomedicine. In this study, crude sulfated polysaccharide fractions (denominated Hf1, Hf2 and Hf3) were obtained from the red marine alga Halymenia floresia and the anticoagulant properties of a soluble crude polysaccharide fraction (Hf2s) were assayed. The three differential extractions yielded 38.6%. The polysaccharides are composed mainly of galactose, with small amounts of xylose and glucose. The anticoagulant properties of Hf2s containing 53.8% sulfate and 3% protein was also compared to those of heparin (193.0 IU mg-1) by assays of activated partial thromboplastin time (APTT) and thrombin time (TT) using normal human plasma. Hf2s showed a higher anticoagulant activity (68.4 IU mg-1) than those of Hf1s and Hf3s, whose activities were 37.6 and 36.6 IU mg-1, respectively. The compound was less active than heparin, but its anticoagulant mechanism suggested that it is dependent on cofactor heparin II to inhibit thrombin activity, but not on cofactors VIII and IX. Therefore, the polysaccharide from H. floresia interfered on coagulation cascade.

O aumento da demanda por anticoagulantes para a terapia clínica tem motivado a busca por fontes alternativas de anticoagulantes mais seguros e os polissacarídeos sulfatados de algas marinhas têm ganhado atenção na biomedicina. Objetivou-se obter frações de polissacarídeos sulfatados brutos (denominadas Hf1; Hf2 e Hf3) da alga marinha vermelha Halymenia floresia e para avaliar as propriedades anticoagulantes de uma fração polissacarídica bruta solúvel anticoagulante (Hf2s). As três extrações diferenciais renderam 38,60%. Os polissacarídeos são principalmente compostos de galactose com pequenas quantidades de xilose e glucose. As propriedades anticoagulantes da Hf2s, contendo 53,80% de sulfato e 3% de proteínas, foram também comparadas com a heparina (193,00 UI mg-1) pelo ensaio do tempo de tromboplastina parcial ativada (TTPA) e tempo de trombina (TT), usando plasma humano normal. A Hf2s apresentou maior atividade anticoagulante (68,40 UI mg-1) que Hf1s a Hf3s, cujas atividades foram 37,60 e 36,60 UI mg-1, respectivamente. O composto foi menos ativo que a heparina, mas sugere-se que o mecanismo anticoagulante seja dependente do cofator II da heparina para inibição da atividade da trombina, exceto pelos cofatores VIII a IX. Portanto, o polissacarídeo de H. floresia interferiu na cascata de coagulação.

The value of galactomannan detection in bronchoalveolar lavage fluid in the diagnosis of invasive pulmonary aspergillosis in elderly patients with lung diseases / 中华老年医学杂志

ObjectiveTo evaluate the role of galactomannan (GM) detection in bronchoalveolar lavage fluid (BALF) in the diagnosis of invasive pulmonary aspergillosis (IPA) in elderly patients with lung diseases.MethodsThe elderly patients with lung diseases and suspected of having IPA were enrolled. BALF for culture and GM detection, and serum samples for GM detection were obtained from all participants.According to European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) with host factors, clinical criteria, mycological evidence and histological or cytopathological evidence, all patients were categorized into the proven, probable,possible and no IPA patients. The IPA patients were considered as IPA group while no IPA was considered as control group. ResultsAmong 76 enrolled elderly patients, 18 cases were diagnosed with IPA (1 proven, 11 probable and 6 possible), the remained 58 patients were as control group.Based on a GM index cutoff value of ≥0. 5, the sensitivity, specificity, positive predictive value and negative predictive value for BALF were 83.3％, 82. 8％, 60.0％ and 94.1％, respectively; these variables in serum were 55.60％ , 91.4 ％, 66.7 ％ and 86.9％ , respectively. Using a GM index cutoff value of ≥1.0, the specificity and positive predictive value of both BALF GM and serum GM reached 100％, but the sensitivity and negative predictive value of BALF GM were higher than serum GM (66.7％ vs. 22.2％, 90.60％ vs. 80.60％, respectively). Receiver operating characteristic curve analysis yielded a sensitivity of 83.4％ and a specificity of 96.6％ at a BALF GM index cutoff value of ≥0.725. ConclusionsGM detection in BALF seems to be a useful tool in the diagnosis of IPA in elderly patients with lung diseases,and could be widely used in future.

A carbohydrate-based mechanism of species recognition in sea urchin fertilization

In the present review, we describe a systematic study of the sulfated polysaccharides from marine invertebrates, which led to the discovery of a carbohydrate-based mechanism of sperm-egg recognition during sea urchin fertilization. We have described unique polymers present in these organisms, especially sulfated fucose-rich compounds found in the egg jelly coat of sea urchins. The polysaccharides have simple, linear structures consisting of repeating units of oligosaccharides. They differ among the various species of sea urchins in specific patterns of sulfation and/or position of the glycosidic linkage within their repeating units. These polysaccharides show species specificity in inducing the acrosome reaction in sea urchin sperm, providing a clear-cut example of a signal transduction event regulated by sulfated polysaccharides. This distinct carbohydrate-mediated mechanism of sperm-egg recognition coexists with the bindin-protein system. Possibly, the genes involved in the biosynthesis of these sulfated fucans did not evolve in concordance with evolutionary distance but underwent a dramatic change near the tip of the Strongylocentrotid tree. Overall, we established a direct causal link between the molecular structure of a sulfated polysaccharide and a cellular physiological event - the induction of the sperm acrosome reaction in sea urchins. Small structural changes modulate an entire system of sperm-egg recognition and species-specific fertilization in sea urchins. We demonstrated that sulfated polysaccharides - in addition to their known function in cell proliferation, development, coagulation, and viral infection - mediate fertilization, and respond to evolutionary mechanisms that lead to species diversity.