Effects of sulfated polysaccharides on tumour biology

Effect of carrageenans of different chemical structures in biointerfaces: a Langmuir film study

Carrageenans have unique properties in the pharmaceutical and food industries that involve interactions with lipid interfaces, which may be accessed if surface chemistry techniques are employed. The interaction between three different types of carrageenans with dipalmitoylphosphatidylcholine (DPPC) was investigated using Langmuir monolayers as biointerface models. With a combination of data on Surface Pressure-Area Isotherms and Polarization Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS), the effect of different fractions on DPPC monolayers was compared by considering the chemical and structural differences as well as the anticoagulant activity of each fraction. Thus, a model is proposed in which carrageenans can encompass interactions that are maximized due to geometrical adaptations on behalf of the interactions between polysaccharide sulfate groups and lipid polar heads.

The potential biotechnological applications of the exopolysaccharide produced by the halophilic bacterium Halomonas almeriensis

We have studied the extracellular polysaccharide (EPS) produced by the type strain, M8(T), of the halophilic bacterium Halomonas almeriensis, to ascertain whether it might have any biotechnological applications. All the cultural parameters tested influenced both bacterial growth and polysaccharide production. EPS production was mainly growth-associated and under optimum environmental and nutritional conditions M8(T) excreted about 1.7 g of EPS per litre of culture medium (about 0.4 g of EPS per gram of dry cell weight). Analysis by anion-exchange chromatography and high-performance size-exclusion chromatography indicated that the exopolysaccharide was composed of two fractions, one of 6.3 × 10(6) and another of 1.5 × 10(4) Daltons. The monosaccharide composition of the high-molecular-weight fraction was mannose (72% w/w), glucose (27.5% w/w) and rhamnose (0.5% w/w). The low-molecular-weight fraction contained mannose (70% w/w) and glucose (30% w/w). The EPS has a substantial protein fraction (1.1% w/w) and was capable of emulsifying several hydrophobic substrates, a capacity presumably related to its protein content. The EPS produced solutions of low viscosity with pseudoplastic behaviour. It also had a high capacity for binding some cations. It contained considerable quantities of sulphates (1.4% w/w), an unusual feature in bacterial polysaccharides. All these characteristics render it potentially useful as a biological agent, bio-detoxifier and emulsifier.

Heparanase: a novel target of tumor metastasis therapy

Heparanase plays a key role in promoting tumor angiogenesis, vasiveness and metastasis. This predominant enzyme is primarily responsible for cleaving heparin sulphate, the main polysaccharide constituent of extracellular matrix and basement membrane, thus having become a novel target of tumor therapy. It can prevent tumor growth and metastasis by inhibiting its expression and reducing its activity. This paper reviews the biological characteristics of heparanase as a target of tumor therapy, the significance in tumor progression and tumor therapies, and the prospect of its relating medicine in clinical applications.