Mutation of bacterium Vibrio gazogenes for selective preparation of colorants

A novel marine bacterium strain effectively produced prodiginine type pigments. These colorants could dye wool, silk and synthetic fabrics such as polyester and polyacrylic and also show antibacterial properties against Escherichia coli and Staphylococcus aureus bacteria on the dyed products. Methyl nitrosoguanidine was used as a mutation agent to increase the genetic diversity and the production yield of the bacteria of the family of Vibrio gazogenes. The analysis of the mutated samples showed that two new main colorants as well as three previously found ones were produced. Liquid chromatography electro spray ionization mass spectrometry (LC‐ESI‐MS) and nuclear magnetic resonance (NMR) spectroscopic techniques were used to elucidate the structures of the newly produced colorants. Mass measurements revealed that the colorants C1, C2, C3, C4 have molecular masses of 321, 323, 351, and 295 Da. One unstable colorant C5 with molecular mass of 309 Da was detected as well. The mutated bacteria strains increased the yield of pigment production by about 81% and produced prodigiosin in 97% purity. The antibiotic activities of pure colorants are discussed as well. Based on their bio‐activity and excellent dyeing capabilities, these colorants could be employed in cosmetic and textile industries. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

Semi-allogeneic dendritic cells can induce antigen-specific T-cell activation, which is not enhanced by concurrent alloreactivity

Background

Alloreactive T-cell responses are known to result in the production of large amounts of proinflammatory cytokines capable of activating and maturing dendritic cells (DC). However, it is unclear whether these allogeneic responses could also act as an adjuvant for concurrent antigen-specific responses.

Objective

To examine effects of simultaneous alloreactive and antigen-specific T-cell responses induced by semi-allogeneic DC.

Methods

Semi-allogeneic DC were generated from the F₁ progeny of inbred strains of mice (C57BL/6 and C3H, or C57BL/6 and DBA). We directly primed antigen-specific CD8⁺ and CD4⁺ T-cells from OT-I and OT-II mice, respectively, in the absence of allogeneic responses, in vitro, and in the presence or absence of alloreactivity in vivo.

Results

In vitro, semi-allogeneic DC cross-presented ovalbumin (OVA) to naïve CD8⁺ OT-I transgenic T-cells, primed naïve CD4⁺ OT-II transgenic T-cells and could stimulate strong alloreactive T-cell proliferation in a primary mixed lymphocyte reaction (MLR). In vivo, semi-allogeneic DC migrated efficiently to regional lymph nodes but did not survive there as long as autologous DC. In addition, they were not able to induce cytotoxic T-lymphocyte (CTL) activity to a target peptide, and only weakly stimulated adoptively transferred OT-II cells. The CD4⁺ response was unchanged in allo-tolerized mice, indicating that alloreactive T-cell responses could not provide help for concurrently activated antigen-specific responses. In an EL4 tumour-treatment model, vaccination with semi-allogeneic DC/EL4 fusion hybrids, but not allogeneic DC/EL4 hybrids, significantly increased mouse survival.

Conclusion

Expression of self-Major histocompatibility complex (MHC) by semi-allogeneic DC can cause the induction of antigen-specific immunity, however, concurrently activated allogeneic bystander responses do not provide helper or adjuvant effects.     

Developmental competence and apoptotic gene expression patterns of mature and immature human oocytes retrieved from controlled ovarian stimulation cycles

The purpose was to assess the developmental competence of the in vitro or in vivo matured human oocytes as well as the apoptotic genes expression of cumulus cells (CCs) regarding nuclear maturity status of associated oocytes retrieved from stimulated ICSI cycles. A total of 590 oocytes and the associated CCs were retrieved and divided into groups of test and control according to the nuclear maturity status in order to the developmental evaluation as well as expression patterns of apoptosis-related genes using real time PCR. The fertilization and embryo formation rates were 60.3% and 87.5% vs.69.1% and 92.8% in test and control groups, respectively. Good quality embryos on day 3 were 62.2% in test and 69.1% in control groups. There were significant differences in the rates of normal fertilized as well as unfertilized oocytes between the groups. Also, mRNA levels of some apoptotic genes were significantly higher in the CCs obtained from immature oocytes among patients with premature ovarian factors (POF) rather than other infertility etiologies (p?<?0.001). The data demonstrated the developmental competence of in vitro matured oocytes ?even to good quality cleavage embryos- is not completely consistent with molecular integrity and well-mannered gene expression patterns resulting to ICSI success. It seems that using immature oocytes could be helpful for patients at risk of ovarian hyperstimulation syndrome (OHSS) as the same as patients with diminished ovarian reserve.     

Dietary Fat Influences the Expression of Contractile and Metabolic Genes in Rat Skeletal Muscle

Dietary fat plays a major role in obesity, lipid metabolism, and cardiovascular diseases. To determine whether the intake of different types of dietary fats affect the muscle fiber types that govern the metabolic and contractile properties of the skeletal muscle, we fed male Wistar rats with a 15% fat diet derived from different fat sources. Diets composed of soybean oil (n-6 polyunsaturated fatty acids (PUFA)-rich), fish oil (n-3 PUFA-rich), or lard (low in PUFAs) were administered to the rats for 4 weeks. Myosin heavy chain (MyHC) isoforms were used as biomarkers to delineate the skeletal muscle fiber types. Compared with soybean oil intake, fish oil intake showed significantly lower levels of the fast-type MyHC2B and higher levels of the intermediate-type MyHC2X composition in the extensor digitorum longus (EDL) muscle, which is a fast-type dominant muscle. Concomitantly, MyHC2X mRNA levels in fish oil-fed rats were significantly higher than those observed in the soybean oil-fed rats. The MyHC isoform composition in the lard-fed rats was an intermediate between that of the fish oil and soybean oil-fed rats. Mitochondrial uncoupling protein 3, pyruvate dehydrogenase kinase 4, and porin mRNA showed significantly upregulated levels in the EDL of fish oil-fed rats compared to those observed in soybean oil-fed and lard-fed rats, implying an activation of oxidative metabolism. In contrast, no changes in the composition of MyHC isoforms was observed in the soleus muscle, which is a slow-type dominant muscle. Fatty acid composition in the serum and the muscle was significantly influenced by the type of dietary fat consumed. In conclusion, dietary fat affects the expression of genes related to the contractile and metabolic properties in the fast-type dominant skeletal muscle, where the activation of oxidative metabolism is more pronounced after fish oil intake than that after soybean oil intake.     

Hepatic Encephalopathy: From Metabolic to Neurodegenerative

Neurochemical Research - Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of both acute and chronic liver disease. As a metabolic disorder, HE is considered to be reversible and therefore...     

Superantigenic Activity of emm3 Streptococcus pyogenes Is Abrogated by a Conserved, Naturally Occurring smeZ Mutation

Streptococcus pyogenes M/emm3 strains have been epidemiologically linked with enhanced infection severity and risk of streptococcal toxic shock syndrome (STSS), a syndrome triggered by superantigenic stimulation of T cells. Comparison of S. pyogenes strains causing STSS demonstrated that emm3 strains were surprisingly less mitogenic than other emm-types (emm1, emm12, emm18, emm28, emm87, emm89) both in vitro and in vivo, indicating poor superantigenic activity. We identified a 13 bp deletion in the superantigen smeZ gene of all emm3 strains tested. The deletion led to a premature stop codon in smeZ, and was not present in other major emm-types tested. Expression of a functional non-M3-smeZ gene successfully enhanced mitogenic activity in emm3 S. pyogenes and also restored mitogenic activity to emm1 and emm89 S. pyogenes strains where the smeZ gene had been disrupted. In contrast, the M3-smeZ gene with the 13 bp deletion could not enhance or restore mitogenicity in any of these S. pyogenes strains, confirming that M3-smeZ is non-functional regardless of strain background. The mutation in M3-smeZ reduced the potential for M3 S. pyogenes to induce cytokines in human tonsil, but not during invasive infection of superantigen-sensitive mice. Notwithstanding epidemiological associations with STSS and disease severity, emm3 strains have inherently poor superantigenicity that is explained by a conserved mutation in smeZ.     

Lipo-Chitin Oligosaccharides,Plant Symbiosis Signalling Molecules That Modulate Mammalian Angiogenesis In Vitro

Lipochitin oligosaccharides (LCOs) are signaling molecules required by ecologically and agronomically important bacteria and fungi to establish symbioses with diverse land plants. In plants, oligo-chitins and LCOs can differentially interact with different lysin motif (LysM) receptors and affect innate immunity responses or symbiosis-related pathways. In animals, oligo-chitins also induce innate immunity and other physiological responses but LCO recognition has not been demonstrated. Here LCO and LCO-like compounds are shown to be biologically active in mammals in a structure dependent way through the modulation of angiogenesis, a tightly-regulated process involving the induction and growth of new blood vessels from existing vessels. The testing of 24 LCO, LCO-like or oligo-chitin compounds resulted in structure-dependent effects on angiogenesis in vitro leading to promotion, or inhibition or nil effects. Like plants, the mammalian LCO biological activity depended upon the presence and type of terminal substitutions. Un-substituted oligo-chitins of similar chain lengths were unable to modulate angiogenesis indicating that mammalian cells, like plant cells, can distinguish between LCOs and un-substituted oligo-chitins. The cellular mode-of-action of the biologically active LCOs in mammals was determined. The stimulation or inhibition of endothelial cell adhesion to vitronectin or fibronectin correlated with their pro- or anti-angiogenic activity. Importantly, novel and more easily synthesised LCO-like disaccharide molecules were also biologically active and de-acetylated chitobiose was shown to be the primary structural basis of recognition. Given this, simpler chitin disaccharides derivatives based on the structure of biologically active LCOs were synthesised and purified and these showed biological activity in mammalian cells. Since important chronic disease states are linked to either insufficient or excessive angiogenesis, LCO and LCO-like molecules may have the potential to be a new, carbohydrate-based class of therapeutics for modulating angiogenesis.     

Penconazole induced changes in photosynthesis, ion acquisition and protein profile of Mentha pulegium L. under drought stress

Effect of penconazole (PEN) treatment on drought-stressed Mentha pulegium L. plants was investigated. Six weeks after sowing, seedlings were grown under soil moisture corresponding to 100, 75, 50 and 25 % field capacity (FC) with or without PEN (15 mg l⁻¹) for 4 weeks. Results showed that the seedlings at 75 % FC showed maximum growth and water supply lower than 75 % FC was the threshold of drought-initiated negative effects on seedling growth. Drought stress significantly induced proline and carbohydrate contents and the decreased chlorophyll, photosynthesis parameters, soluble proteins and ion accumulations. Exogenous PEN increased the growth parameters, pigments, photosynthesis and ion accumulations in drought stressed and unstressed plants, but the effects of PEN were more significant under water deficit conditions. PEN also reduced the negative effects of drought by osmotic balance and protein accumulations. Electrophoretic patterns indicated that PEN treatment increased the intensity of some protein bands with the molecular weights of 30 kDa in shoot and 31 kDa in roots, and several new protein bands with the molecular masses between 116 and 14 kDa appeared in leaves, shoots and roots. These results suggest that the PEN application can be a useful tool in alleviation of effects of drought stress in M. pulegium plants.