Preparation and in vitro release of drug-loaded microparticles for oral delivery using wholegrain sorghum kafirin protein

Kafirin microparticles have been proposed as an oral nutraceutical and drug delivery system. This study investigates microparticles formed with kafirin extracted from white and raw versus cooked red sorghum grains as an oral delivery system. Targeted delivery to the colon would be beneficial for medication such as prednisolone, which is used in the management of inflammatory bowel disease. Therefore, prednisolone was loaded into microparticles of kafirin from the different sources using phase separation. Differences were observed in the protein content, in vitro protein digestibility, and protein electrophoretic profile of the various sources of sorghum grains, kafirin extracts, and kafirin microparticles. For all of the formulations, the majority of the loaded prednisolone was not released in in vitro conditions simulating the upper gastrointestinal tract, indicating that most of the encapsulated drug could reach the target area of the lower gastrointestinal tract. This suggests that these kafirin microparticles may have potential as a colon-targeted nutraceutical and drug delivery system.

Genetic control of wheat quality: interactions between chromosomal regions determining protein content and composition, dough rheology, and sponge and dough baking properties

While the genetic control of wheat processing characteristics such as dough rheology is well understood, limited information is available concerning the genetic control of baking parameters, particularly sponge and dough (S&D) baking. In this study, a quantitative trait loci (QTL) analysis was performed using a population of doubled haploid lines derived from a cross between Australian cultivars Kukri x Janz grown at sites across different Australian wheat production zones (Queensland in 2001 and 2002 and Southern and Northern New South Wales in 2003) in order to examine the genetic control of protein content, protein expression, dough rheology and sponge and dough baking performance. The study highlighted the inconsistent genetic control of protein content across the test sites, with only two loci (3A and 7A) showing QTL at three of the five sites. Dough rheology QTL were highly consistent across the 5 sites, with major effects associated with the Glu-B1 and Glu-D1 loci. The Glu-D1 5 + 10 allele had consistent effects on S&D properties across sites; however, there was no evidence for a positive effect of the high dough strength Glu-B1-al allele at Glu-B1. A second locus on 5D had positive effects on S&D baking at three of five sites. This study demonstrated that dough rheology measurements were poor predictors of S&D quality. In the absence of robust predictive tests, high heritability values for S&D demonstrate that direct selection is the current best option for achieving genetic gain in this product category.

"On-the-go" NIT technology to assess protein and moisture during harvest of wheat breeding trials.

In this study, we investigated the application of “on-the-go” assessment of wheat protein and moisture under a breeding trial situation.

Future switching technology: bacterial protein-based programmable all-optical switch for integrated optics applications?

We report on the bacterial protein-based all-optical switches which operate at low laser power, high speed and fulfil most of the requirements to be an ideal all-optical switch without any moving parts involved. This consists of conventional optical waveguides coated with bacteriorhodopsin films at switching locations. The principle of operation of the switch is based on the light-induced refractive index change of bacteriorhodopsin. This approach opens the possibility of realizing proteinbased all-optical switches for communication network, integrated optics and optical computers.

Bioavailability of zinc and copper in biosolids compared to their soluble salts.

For essential elements, such as copper (Cu) and zinc (Zn), the bioavailability in biosolids is important from a nutrient release and a potential contamination perspective. Most ecotoxicity studies are done using metal salts and it has been argued that the bioavailability of metals in biosolids can be different to that of metal salts. We compared the bioavailability of Cu and Zn in biosolids with those of metal salts in the same soils using twelve Australian field trials. Three different measures of bioavailability were assessed: soil solution extraction, CaCl2 extractable fractions and plant uptake. The results showed that bioavailability for Zn was similar in biosolid and salt treatments. For Cu, the results were inconclusive due to strong Cu homeostasis in plants and dissolved organic matter interference in extractable measures. We therefore recommend using isotope dilution methods to assess differences in Cu availability between biosolid and salt treatments.

Purification and properties of riboflavin-binding protein from the egg white of the duck (Anas platyrhynckos).

Riboflavin-binding protein was purified from the egg white of domestic duck and some of its properties were investigated. The protein was homogeneous by the criteria of gel filtration on Sephadex G-100 and electrophoresis on sodium dodecyl sulphate-polyacrylamide gels, had molecular weight of 36 000 ± 1000 and, unlike the chicken egg white protein (Mr 32 000 ± 2000), was devoid of covalently-bound carbohydrate. It was similar to the chicken riboflavin-binding protein in its behavior on ion-exchange celluloses and affinity to interact with the flavin and its coenzymes, but differed significantly in amino acid composition in that it completely lacked proline and contained less of methionine and arginine. The protein partially cross-reacted with the specific antiserum to chicken riboflavin-binding protein with a spur during immunodiffusion analysis.

Nucleosome core protein: Asymmetric dissociation of the octamer

The octameric nucleosomal core-histone complex, (H2A)2-(H2B)2-(H3)2-(H4)2, isolated from rat liver, undergoes dissociation during gel exclusion chromatography as a result of dilution occurring in the columns. The elution pattern at pH 7.0 and 4°C showed a sharp leading peak containing all four histones but predominantly H3 and H4, and a trailing peak containing equal amounts of histones H2A and H2B. As column length was increased the area under the leading peak decreased and that under the trailing peak increased. In addition the relative positions of the two peaks varied with column length. From an analysis of the data on increase in elution volume of the leading peak in relation to column length an apparent molecular weight of 86 000 was calculated for the undissociated molecule. Its apparent molecular weight, histone composition and pattern of further dissociation in relation to column length suggest that this species is the hexamer, (H2A-H2B)-(H3)2-(H4)2. At pH 7.0 and 4°C the dissociation of the core complex appears to be as follows: (H2A)2-(H2B)2-(H3)2-(H4)2 → (H2A-H2B) + (H2A-H2B)-(H3)2-(H4)2 → 2(H2A-H2B) + (H3)2-(H4)2 This dissociation was accelerated by an increase in temperature or decrease in pH and was accompanied by marked conformational changes as judged by circular dichroism measurements.

Interaction of rat testis protein, TP, with nucleic acids in vitro. Fluorescence quenching, UV absorption, and thermal denaturation studies

The nucleic acid binding properties of the testis protein, TP, were studied with the help of physical techniques, namely, fluorescence quenching, UV difference absorption spectroscopy, and thermal melting. Results of quenching of tyrosine fluorescence of TP upon its binding to double-stranded and denatured rat liver nucleosome core DNA and poly(rA) suggest that the tyrosine residues of TP interact/intercalate with the bases of these nucleic acids. From the fluorescence quenching data, obtained at 50 mM NaCl concentration, the apparent association constants for binding of TP to native and denatured DNA and poly(rA) were calculated to be 4.4 X 10(3) M-1, 2.86 X 10(4) M-1, and 8.5 X 10(4) M-1, respectively. UV difference absorption spectra upon TP binding to poly(rA) and rat liver core DNA showed a TP-induced hyperchromicity at 260 nm which is suggestive of local melting of poly(rA) and DNA. The results from thermal melting studies of binding of TP to calf thymus DNA at 1 mM NaCl as well as 50 mM NaCl showed that although at 1 mM NaCl TP brings about a slight stabilization of the DNA against thermal melting, a destabilization of the DNA was observed at 50 mM NaCl. From these results it is concluded that TP, having a higher affinity for single-stranded nucleic acids, destabilizes double- stranded DNA, thus behaving like a DNA-melting protein.

Key Role of Fe2+ in Epithiospecifier Protein Activity.

The chemical nature of the hydrolysis products from the glucosinolate-myrosinase system depends on the presence or absence of supplementary proteins such as epithiospecifier proteins (ESPs). ESPs promote the formation of epithionitriles from terminal alkenyl glucosinolates and, as recent evidence suggests, simple nitriles at the expense of isothiocyanates. From a human health perspective isothiocyanates are the most important because they are major inducers of carcinogen-detoxifying enzymes. Fe2+ is an essential factor in ESP activity, although several recent studies have highlighted discrepancies in the understanding of the ESP-iron interaction. To investigate further the role iron species play in regulating ESP activity, four ESP-containing seedpowders were analyzed for ESP and myrosinase activities, endogenous iron content, and glucosinolate degradation products after the addition of iron species, specific chelators, and reducing agents. For the first time this paper shows the effect of these additions on the hydrolysis of individual glucosinolates that constitute the total pool. Aged seeds and 3-day seedlings were also tested to investigate the effects of seed storage and early plant development on iron levels and ESP activity. The four ESP-containing plant systems tested gave two distinctive responses, thus providing strong evidence that ESPs vary markedly in their Fe2+ requirement for activity. The results also indicated that reduction of ferric to ferrous iron drives variations in ESP activity during early plant development. The reverse oxidation reaction provided a convincing explanation for the loss of ESP activity during seed storage. Aged seeds produced seedlings with substantially lower ESP activity, and there was a concomitant loss in germination rate. It was concluded that manipulation of endogenous iron levels of ESP-containing plants could increase the conversion of glucosinolates to isothiocyanates and enhance potential health benefits.

Estrogen Induction Of Biotin-Binding Protein In Immature Chicks - Kinetics, Hormonal Specificity And Modulation

Employing a specific radioimmunoassay for quantification, the kinetics of estrogen-induced elevation in the plasma concentration of biotin-binding protein (BBP) in immature male chicks was investigated. A single injection of the steroid hormone enhanced the plasma BBP content several-fold at 6 h, reaching peak levels around 48 h and declining thereafter. A 2-fold amplification of the response was evident during secondary stimulation with the hormone. The magnitude of the response was hormonal dose-dependent while the initial lag phase and the time of peak protein accumulation were unaltered within the hormonal doses tested. The circulatory half-life of the specific protein in normal and estrogenized birds was 10 h. Hyperthyroidism markedly decreased the hormonal response while the opposite effect was seen during hypothyroidism. The antiestrogens E- and Z-clomiphene citrate effectively blocked the protein induction whereas progesterone, either alone or in combination with estrogen, was ineffective in modulating the induction. Cycloheximide administration drastically inhibited the inductive response. The above observations clearly suggest that the genes corresponding to the two isofunctional proteins of chicken egg, viz. BBP and avidin, are differentially regulated.

Estrogen modulation of riboflavin carrier protein in the bonnet monkey (Macaca radiata)

Circulatory concentrations of riboflavin carrier protein (RCP) were quantitated in bonnet macaques by employing a heterologous radioimmunoassay involving 125I-labelled chicken RCP and its antiserum. The levels of monkey RCP in the serum seem to be governed by the estrogenic status of the animals. An increase in concentration of serum estradiol in the adult females during the menstrual cycle and early pregnancy could be correlated with enhanced serum RCP levels. Estadiol-17β administered to both immature female and male monkeys, specifically brought about elevated levels of RCP with a slower time course of response in males than in females. These results could be a reflection of a more rapid decline of both circulatory estrogen and RCP concentrations in male serum. Repeated administration of estradiol-17β to male animals led to prolonged elevated levels of RCP following estrogen administration. Thus, it would appear that the evolutionary conservation of RCPs from the aves to the primates encompasses not only their physicochemical similarities but also extends to the estrogenic modulation of their elaboration.

Baker's yeast expressing the Japanese encephalitis virus envelope protein on its cell surface: induction of an antigen-specific but non-neutralizing antibody response

Live recombinant Saccharomyces cerevisiae yeast expressing the envelope antigen of Japanese encephalitis virus (JEV) on the outer mannoprotein layer of the cell wall were examined for their ability to induce antigen-specific antibody responses in mice. When used as a modelantigen, parenteral immunization of mice with surface-expressing GFP yeast induced a strong anti-GFP antibody response in the absence of adjuvants. This antigen delivery approach was then used for a more stringent system, such as the envelope protein of JEV, which is a neurotropic virus requiring neutralizing antibodies for protection.Although 70% of cells were detected to express the total envelope protein on the surface by antibodies raised to the bacterially expressed protein, polyclonal anti-JEV antibodies failed to react with them. In marked contrast, yeast expressing the envelope fragments 238-398, 373-399 and 373-500 in front of a Gly-Ser linker were detected by anti-JEV antibodies as well as a monoclonal antibody but not by antibodies raised to the bacterially expressed protein. Immunization of mice with these surface-expressing recombinants resulted in a strong antibody response. However, the antibodies failed to neutralize the virus, although the fragments were selected based on neutralizing determinants.