New Insights into the Structure of Kappa/Beta-Carrageenan: A Novel Potential Inhibitor of HIV-1

New insights into the structure of the hybrid κ/β-carrageenan (κ/β-CRG) of the red alga Tichocarpus crinitus have been obtained. Carrageenan oligosaccharides were prepared through the chemical and enzymatic depolymerization of κ/β-CRG with κ-carrageenase and its the enzyme-resistant fraction. The composition and distribution of the repetition units of κ/β- CRG were investigated by using the negative ion tandem MALDI-TOFMS and ESIMS method, which made it possible to prove and characterize the hybrid structure of this polysaccharide. An analysis revealed the blockwise distribution of the long β-blocks along the polysaccharide chain, with the inclusion of κ/β, μ/ν-blocks and some ι-blocks. Furthermore, the desulfated κ/β-CRG was shown to contain of –G–D– repeating units up to 3.5 kDa. Previous studies have demonstrated that CRGs suppress the replication of several viruses. Here, we established that κ/β-CRG and its oligosaccharides significantly inhibit the transduction efficiency of replication-defective lentiviral particles pseudotyped with the envelope proteins of three different viruses. We found that the polysaccharide and its oligosaccharides strongly reduced the transduction efficiency of lentiviral particles pseudotyped with GP160—the envelope protein of the human immunodeficiency virus HIV-1—when added to T-lymphocyte Jurkat cells. The CRG oligosaccharides displayed significantly higher antiviral activity.

Morphological characterization of biominerals from five multicellular marine algae species

Silica biominerals are deposited as amorphous solid structures in plant cells and tissues, providing rigidity to different plant parts and assisting in defence. The shape and size of phytoliths are well established and serve as a useful tool in taxonomic analyses. For the first time we extracted and studied silica biominerals of five marine macroalgae, which we observed by light microscopy, scanning electron microscopy, and X-ray diffraction analysis (XRD). More than nine different morphotypes of phytoliths ranging from ≥ 10 to ≥ 350 μm in size were found. Some of them were phytoliths made of silica while others showed characteristics of different minerals of calcium. In our study, the “honeycomb” formations were only recorded in Laurencia tropica Yamada and pyramid tabular ones were found only in Tichocarpus crinitus (S.G. Gmelin) Ruprecht. The XRD analysis showed that they consisted of virgilite and gypsum substance, respectively. Silica phytoliths are intrinsic parts of the algae and their morphological characterization can provide the basis for palaeo-reconstruction and taxonomic investigation of brown and red algae in palaeontological studies of fossils where all organic matter has decayed.

Hexagonal Phytolithes from Red Alga Tichocarpus crinitus

In current work unique hexagonal microparticles of silicon oxide (phytolite), isolated from the red algae Tichocarpus crinitus, which grows in the Sea of Japan described. The structures of poytolites are characterized by the methods of optical microscopy and scanning electron microscopy. The role of these formations in plant life and the mechanism of their synthesis remains unclear.