A novel calmodulin-like protein from the liver fluke, Fasciola hepatica

An 18.2 kDa protein from the liver fluke, Fasciola hepatica has been identified and characterised. The protein shows strongest sequence similarity to egg antigen proteins from Schistosoma mansoni, Schistosoma japonicum and Clonorchis sinensis. The protein is predicted to adopt a calmodulin-like fold; it thus represents the third calmodulin-like protein to be characterised in F. hepatica and has been named FhCaM3. Compared to the classical calmodulin structure there are some variations. Most noticeably, the central, linker helix is disrupted by a cysteine residue. Alkaline native gel electrophoresis showed that FhCaM3 binds calcium ions. This binding event increases the ability of the protein to bind the hydrophobic fluorescent probe 8-anilinonaphthalene-1-sulphonate, consistent with an increase in surface hydrophobicity as seen in other calmodulins. FhCaM3 binds to the calmodulin antagonists trifluoperazine and W7, but not to the myosin regulatory light chain binding compound praziquantel. Immunolocalisation demonstrated that the protein is found in eggs and vitelline cells. Given the critical role of calcium ions in egg formation and hatching this suggests that FhCaM3 may play a role in calcium signalling in these processes. Consequently the antagonism of FhCaM3 may, potentially, offer a method for inhibiting egg production and thus reducing the spread of infection.

Misfolding of galactose 1-phosphate uridylyltransferase can result in type I galactosemia

Type I galactosemia is a genetic disorder that is caused by the impairment of galactose-1-phosphate uridylyltransferase (GALT; EC 2.7.7.12). Although a large number of mutations have been detected through genetic screening of the human GALT (hGALT) locus, for many it is not known how they cause their effects. The majority of these mutations are missense, with predicted substitutions scattered throughout the enzyme structure and thus causing impairment by other means rather than direct alterations to the active site. To clarify the fundamental, molecular basis of hGALT impairment we studied five disease-associated variants p.D28Y, p.L74P, p.F171S, p.F194L and p.R333G using both a yeast model and purified, recombinant proteins. In a yeast expression system there was a correlation between lysate activity and the ability to rescue growth in the presence of galactose, except for p.R333G. Kinetic analysis of the purified proteins quantified each variant's level of enzymatic impairment and demonstrated that this was largely due to altered substrate binding. Increased surface hydrophobicity, altered thermal stability and changes in proteolytic sensitivity were also detected. Our results demonstrate that hGALT requires a level of flexibility to function optimally and that altered folding is the underlying reason of impairment in all the variants tested here. This indicates that misfolding is a common, molecular basis of hGALT deficiency and suggests the potential of pharmacological chaperones and proteostasis regulators as novel therapeutic approaches for type I galactosemia.

Thermal stability of myofibrillar protein from Indian major carps

The characteristics and stability of natural actomyosin (NAM) from rohu (Labeo rohita), catla (Catla catla) and mrigal (Cirrhinus mrigala) were investigated. The total extractable actomyosin (AM) was higher (7.60mgml−1) in the case of rohu compared with that from catla and mrigal (5mgml−1). Although the specific AM ATPase activity was similar (0.43–0.5 μmolPmin−1 mgP−1) among the three species, the total ATPase activity was lower in mrigal (25 μmol g−1 meat) compared with the other species (37 μmol g−1 meat). The inactivation rate constants (kd) of AM Ca ATPase activity showed differences in the stabilities of actomyosin among these fish, the actomyosin from catla being least stable. The NAM from these species was stable up to 20 ◦C at pH 7.0. Catla AM became unstable at 30 ◦C, while rohu and mrigal AM could withstand up to 45 ◦C. The thermal denaturation with respect to solubility, turbidity, ATPase activity, sulphhydryl group and surface hydrophobicity showed noticeable changes at around these temperatures

Effects of Extrusion on the Emulsifying Properties of Rumen and Soy Protein

Defatted rumen protein and soy protein concentrate were extruded in a 15.5:1 L/D single-screw extruder at the optimum conditions for their expansion (150A degrees C and 35% moisture, and 130A degrees C and 35% moisture, respectively). Emulsions were produced with these proteins and studied by rheology and time domain low-resolution (1)H nuclear magnetic resonance (TD-NMR). Extrusion increased storage modulus of rumen protein emulsions. The opposite was observed for soy protein. Mechanical relaxation showed the existence of three relaxing components in the emulsions whose relative contributions were changed by extrusion. Likewise, spin-spin relaxation time constants (T (2)) measured by TD-NMR also showed three major distinct populations of protons in respect to their mobility that were also altered by extrusion. Extrusion increased surface hydrophobicity of both rumen and soy protein. Solubility of rumen protein increased with extrusion whereas soy protein had its solubility decreased after processing. Extrusion promoted molecular reorganization of protein, increasing its superficial hydrophobicity, affecting its interfacial properties and improving its emulsifying behavior. The results show that extrusion can promote the use of rumen, a by-product waste from the meat industry, in human nutrition by replacing soy protein in food emulsions.

Wettability of Aqueous Rhamnolipids Solutions Produced by Pseudomonas aeruginosa LBI

The wetting behavior of rhamnolipids produced by Pseudomonas aeruginosa LBI strain grown on waste oil substrate and sodium dodecyl sulfate (SDS) on glass, polyethylene terephthalate (PET), poly(vinyl chloride) (PVC), poly(epsilon-caprolactone) (PCL) and polymer blend (PVC-PCL) was investigated by the measuring contact angle of sessile drops, to determine the wetting characteristics of rhamnolipids. The comparison of the wetting profiles showed that at low SDS and rhamnolipid concentrations, the contact angle increased and when the concentration of the surfactant increased further, the contact angle decreased. The blend surface (PVC-PCL) showed better wettability than the homopolymers themselves and the blend changed the surface hydrophobicity of the polymer, making it more hydrophilic. The rhamnolipids produced by the LBI strain exhibited superior wetting abilities than the chemical surfactant SDS one. This is the first work that evaluates the wetting properties of rhamnolipids on polymer blends.

Superhydrophobic fabrics prepared by silica coating

In this work, a silica sol prepared by co-hydrolysis and co-condensation of TEGS (Tetraethylrthosilicate) and alkyl silane under alkaline condition was applied to polyester, wool, and cotton fabrics. The water contact angle measurement indicated considerable increase in the surface hydrophobicity of the sol-treated fabrics. Five different alky silanes were used, namely methyltritthoxysilane (MTES), pheryl triethoxysilane (PTES), n-octyltricthoxysilane (OTES), hexadecyl trimethoxysilan (HDTMS), and tridecafluorooctyl triethoxysilane (FAS), and the water contact anglc (CA) for the coated fabrics ranged between 1300 and 174°. The alkyl silane used influenced the CA valuc, and the silica coating from FAS, HDTMS and PTES snowed CA value greater than ISO', indicating the formation of superhydrophobicity. The fabric coated by the fluorinated silica (TEOS/FAS) has a water contact angle as high as 174°. The treated polyester fabric showed a slightly higher CA value than the wool and cotton fabrics, under the same coating condition.
The coating surface was characterized by SEM, EDX, TEM, FTlR, XPS and AFM. The results showed that silica nanoparticles with thc sizc in the range of 50-ISOnm werc formed in the cohydrolyzed silica sol, and these particles had a core-shell structure with many alkyl groups gathering on the surface region. The formation of superhydrophobic surface was attributed to the nano-structured surface coating with a low surface energy.

Superhydrophobic modification of polyimide films based on gold-coated porous silver nanostructures and self-assembled monolayers

We present a facile and effective method for controlling the surface hydrophobicity of polyimide films from sticky to superhydrophobic properties by tailoring their topographies. Nanostructured silver layers were produced on polyimide films by treatment with aqueous KOH and AgNO3, followed by thermal treatment at 200 degrees C or higher temperatures. Further modification of the gold-coated silver layers with n-dodecanethiol led to hydrophobic surfaces. Different morphologies of the silver layers at the micro- and nano-meter scales, which result in the variety of hydrophobicity, can be tailored by controlling the thermal treatment temperature. Surfaces prepared at 320 degrees C showed a sticky property that water drops did not slide off even when the sample was held upside down. Superhydrophobic surfaces were obtained when the temperature was above 340 degrees C. A remarkable superhydrophobicity, as evidenced by a very large water contact angle of 162 degrees and a very small sliding angle of 7 degrees, was achieved by heating the modified polyimide films at 360 degrees C. This is also the first example for superhydrophobic modification of polyimide films.

A study on the photostability of photochromic fabrics from hybrid organosilica coatings

Photochromic fabrics were prepared using a coating solution containing photochromic dyes and silica sol-gel. The photochromic effect was rapid. The effect of three different post treatments on the optical and durability of the photochromic fabrics was evaluated. These included incorporating a UV stabilizer, increasing the surface hydrophobicity by fluorinating the pores, and blockading the dye-containing pores with additional silica coating. All the treatments improved photostability, without significantly affecting response/fading speeds.

Evaluation of fungal adherence to plasma-modified polymethylmethacrylate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Wettability of Aqueous Rhamnolipids Solutions Produced by Pseudomonas aeruginosa LBI

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Enhanced bulk and superficial hydrophobicities of starch-based bionanocomposites by addition of clay

In this work, thermoplastic starch (TPS)-clay bionanocomposites were obtained by an innovative methodology using a combination of methodologies commonly used in the composites and nanocomposites preparations. The main objectives or novelties were to confirm efficiency of the processing methodology by field emission gun scanning electron microscopy and investigate the effect of clay content on the spectroscopic, bulk and surface hydrophilic/hydrophobic properties of these bionanocomposites. Raman and FTIR spectroscopies confirmed the changes in the spectroscopic properties of the TPS bionanocomposites with the addition of the clay materials. Water absorption and contact angle measurements were also used to analyze the effect of the clay content on the hydrophilic properties of the TPS bionanocomposites. The results also showed that the addition of the cloisite-Na+ clay increased the bulk and surface hydrophobicities of the TPS matrix, which may increase its industrial application, particularly in manufacturing of food containers. © 2013 Elsevier B.V.

Avaliação do método de Iwatsu et al., (1981) para isolamento de leveduras negras do solo, degradadoras de hidrocarbonetos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biofilms of Candida albicans serotypes A and B differ in their sensitivity to photodynamic therapy

Candida albicans is classified into different serotypes according to cell wall mannan composition and cell surface hydrophobicity. Since the effectiveness of photodynamic therapy (PDT) depends on the cell wall structure of microorganisms, the objective of this study was to compare the sensitivity of in vitro biofilms of C. albicans serotypes A and B to antimicrobial PDT. Reference strains of C. albicans serotype A (ATCC 36801) and serotype B (ATCC 36802) were used for the assays. A gallium-aluminum-arsenide laser (660 nm) was used as the light source and methylene blue (300 mu M) as the photosensitizer. After biofilm formation on the bottom of a 96-well microplate for 48 h, each Candida strain was submitted to assays: PDT consisting of laser and photosensitizer application (L + P+), laser application alone (L + P-), photosensitizer application alone (L-P+), and application of saline as control (L-P-). After treatment, biofilm cells were scraped off and transferred to tubes containing PBS. The content of the tubes was homogenized, diluted, and seeded onto Sabouraud agar plates to determine the number of colony-forming units (CFU/mL). The results were compared by analysis of variance and Tukey test (p < 0.05). The two strains studied were sensitive to PDT (L + P+), with a log reduction of 0.49 for serotype A and of 2.34 for serotype B. Laser application alone only reduced serotype B cells (0.53 log), and the use of the photosensitizer alone had no effect on the strains tested. It can be concluded that in vitro biofilms of C. albicans serotype B were more sensitive to PDT.