secreted cytokines of th1 (t-helper)/th2 cells play an important role in the pathogenesis of many diseases. th1 cells secrete predominantly ifn-γ and il-2 which regulate cell-mediated immunity against intracellular pathogens and tumors. in this study, expression of ifn-γ was studied using semiquantitative rt-pcr. in brief, lymphocytes of a healthy donor were stimulated with pha (1μg/106 cell/ml...

This review focuses on the factors that determine the molecular weight of polyhydroxyalkanoate (PHA), an aliphatic polyester synthesized by bacteria for carbon and energy storage. PHA is a polymer with good thermoplastic, biodegradable, biocompatible and renewable properties. Therefore, it has attracted considerable attention as an environmentally friendly and biomedical material. Because the m...

Polyhydroxyalkanoates (PHA) envisage a potential biomaterial alternative to replacing synthetic polymers for their biodegradability and biocompatibility. Modification approaches exploit the attributes adjust intrinsic hydrophobic properties, such as blending produce new polymer mix with novel properties. Functionalization of PHA, especially chemical grafting, perform introduce additional compou...

Phytohemagglutinin (PHA), the seed lectin of the common bean, accumulates in protein storage vacuoles of storage parenchyma cells in cotyledons. When expressed in yeast, PHA is efficiently targeted to the yeast vacuole [Tague and Chrispeels (1987). J. Cell Biol. 105, 1971-1979]. To identify vacuolar sorting information in PHA, a series of 3' deletions of the PHA gene were fused in-frame to a tr...

This study explored the potential of using Rhodosprillum rubrum as the biological vehicle to convert chemically simple carbon precursors to a value-added bio-based product, the biopolymer PHA. R. rubrum strains were bioengineered to overexpress individually or in various combinations, six PHA biosynthetic genes (phaC1, phaA, phaB, phaC2, phaC3, and phaJ), and the resulting nine over-expressing ...

This study investigated the apparent genetic redundancy in the biosynthesis of polyhydroxyalkanoates (PHAs) in the Rhodospirillum rubrum genome revealed by the occurrence of three homologous PHA polymerase genes (phaC1, phaC2, and phaC3). In vitro biochemical assays established that each gene product encodes PHA polymerase. A series of single, double, and triple phaC deletion mutants were chara...

Phytohemagglutinin (PHA), an abundant vacuolar seed protein of the common bean (Phaseolus vulgaris), is a tetramer of two homologous polypeptides, PHA-E and PHA-L. The roots of bean seedlings release into the culture medium a cross-reacting lectin that is most closely related to PHA-E. Reverse-transcriptase polymerase chain reaction with root mRNA as template was used to identify PHA transcript...

Bdellovibrio bacteriovorus HD100 is an obligate predator that invades and grows within the periplasm of Gram-negative bacteria, including mcl-polyhydroxyalkanoate (PHA) producers such as Pseudomonas putida. We investigated the impact of prey PHA content on the predator fitness and the potential advantages for preying on a PHA producer. Using a new procedure to control P. putida KT2442 cell size...

This paper indicates that activated sludge under certain conditions can achieve levels of polyhydroxyalkanoates (PHA) accumulation which would enable the economic recovery of this precursor of biodegradable plastics. The effects of C/N ratio and temperature on polyhydroxyalkanoates production were evaluated. Acetate uptake, ammonium consumption, oxygen uptake and PHA production were studied und...