Inhibition of sustained smooth muscle contraction by PKA and PKG preferentially mediated by phosphorylation of RhoA

The role of RhoA in myosin light-chain (MLC)(20) dephosphorylation and smooth muscle relaxation by PKA and PKG was examined in freshly dispersed and cultured smooth muscle cells expressing wild-type RhoA, constitutively active Rho(V14), and phosphorylation site-deficient Rho(A188). Activators of PKA (5,6-dichloro-1-beta-ribofuranosyl benzimidazole 3',5'-cyclic monophosphothionate, Sp-isomer; cBIMPS) or PKG [8-(4-chlorophenylthio)guanosine 3',5'-cyclic monophosphate (8-pCPT-cGMP), sodium nitroprusside (SNP)] or both PKA and PKG (VIP) induced phosphorylation of constitutively active Rho(V14) and agonist (ACh)- or GTPgammaS-stimulated wild-type RhoA but not Rho(A188). Phosphorylation was accompanied by translocation of membrane-bound wild-type RhoA and Rho(V14) to the cytosol and complete inhibition of ACh-stimulated Rho kinase and phospholipase D activities, RhoA/Rho kinase association, MLC(20) phosphorylation, and sustained muscle contraction. Each of these events was blocked depending on the agent used, by the PKG inhibitor KT5823 or the PKA inhibitor myristoylated PKI. Inhibitors were used at a concentration (1 microM) previously shown by direct measurement of kinase activity to selectively inhibit the corresponding kinase. In muscle cells overexpressing the active phosphorylation site-deficient mutant Rho(A188), MLC(20) phosphorylation was partly inhibited by SNP, VIP, cBIMPS, and 8-pCPT-cGMP, suggesting the existence of an independent inhibitory mechanism downstream of RhoA. Results demonstrate that dephosphorylation of MLC(20) and smooth muscle relaxation are preferentially mediated by PKG- and PKA-dependent phosphorylation and inactivation of RhoA.     

Antigen-specific CD4+ T cells produce sufficient IFN-gamma to mediate robust protective immunity against genital Chlamydia muridarum infection

Chlamydia has been shown to evade host-specific IFN-gamma-mediated bacterial killing; however, IFN-gamma-deficient mice exhibit suboptimal late phase vaginal Chlamydia muridarum clearance, greater dissemination, and oviduct pathology. These findings introduce constraints in understanding results from murine chlamydial vaccination studies in context of potential implications to humans. In this study, we used mice deficient in either IFN-gamma or the IFN-gamma receptor for intranasal vaccination with a defined secreted chlamydial Ag, chlamydial protease-like activity factor (CPAF), plus CpG and examined the role of IFN-gamma derived from adoptively transferred Ag-specific CD4+ T cells in protective immunity against genital C. muridarum infection. We found that early Ag-specific IFN-gamma induction and CD4+ T cell infiltration correlates with the onset of genital chlamydial clearance. Adoptively transferred IFN-gamma competent CPAF-specific CD4+ T cells failed to enhance the resolution of genital chlamydial infection within recipient IFN-gamma receptor-deficient mice. Conversely, IFN-gamma production from adoptively transferred CPAF-specific CD4+ T cells was sufficient in IFN-gamma-deficient mice to induce early resolution of infection and reduction of subsequent pathology. These results provide the first direct evidence that enhanced anti-C. muridarum protective immunity induced by Ag-specific CD4+ T cells is dependent upon IFN-gamma signaling and that such cells produce sufficient IFN-gamma to mediate the protective effects. Additionally, MHC class II pathway was sufficient for induction of robust protective anti-C. muridarum immunity. Thus, targeting soluble candidate Ags via MHC class II to CD4+ T cells may be a viable vaccine strategy to induce optimal IFN-gamma production for effective protective immunity against human genital chlamydial infection.     

Thidiazuron-induced somatic embryogenesis in intact seedlings of peanut (Arachis hypogaea): Endogenous growth regulator levels and significance of cotyledons

The regulatory role of thidiazuron (TDZ) and explant factors in imparting somatic embryogenic potential was assessed in relation to endogenous growth regulator levels in peanut ( Arachis hypogaea L. cv. Tango). TDZ induced somatic embryogenesis over a range of concentrations (0.5 to 10 μ M ). Culture of seedlings for just 2 days on TDZ-supplemented medium was sufficient to induce somatic embryogenesis. Seedling age and retention or removal of cotyledons during culture influenced morphogenic potential significantly. The younger the seedlings, the better was the embryogenic response to TDZ treatment. The embryogenic potential of seedlings was limited for explants with no cotyledons and they did not respond to increasing levels of TDZ. In contrast, retention of at least one or both the cotyledons resulted in increased response to TDZ. Endogenous levels of cytokinins, auxins and abscisic acid were influenced by TDZ treatment, while TDZ itself was detected only in the cotyledons. The cytokinin N⁶-(2-iso-pentenyl)adenine (2iP) fluctuated on a 10-day cycle in the cotyledons; TDZ treatment suppressed this change and caused an overall decrease in the pool of available 2iP in the tissue. It appeared that TDZ induced somatic embryogenesis in peanut by influencing endogenous levels of both auxin and cytokinins.     

Europium doped Sr2YNbO6 double perovskite phosphor for photoluminescence and thermoluminescence properties

A luminescent double perovskite phosphor Sr₂YNbO₆ doped with Eu³⁺ crystallized to the monoclinic phase and was synthesized successfully via a conventional high-temperature combustion method. The formation of the crystal structure, phase purity, and surface morphology were studied using X-ray diffraction patterns and scanning electron microscopy. The characteristic vibrations between the atoms of the functional groups present in phosphor were studied using Fourier transform infrared spectra analysis. The luminescence properties of the prepared phosphors were investigated in terms of photoluminescence (PL) and thermoluminescence (TL). PL excitation spectra exhibited charge transfer bands and the characteristic 4f⁶ transitions of Eu³⁺. A prominent PL emission was obtained for the phosphor doped with 4 mol% Eu³⁺ under the 396 nm excitation wavelength. PL emission quenching was observed for the higher doping concentrations due to a multipole–multipole interaction. A highly intense PL emission arose due to the hypersensitive ⁵D₀–⁷F₂ electric dipole transition of Eu³⁺ that dominated the emission spectra. The thermal stability of the phosphor was examined through temperature-dependent PL. The TL properties of the Sr₂YNbO₆ double perovskites irradiated with a ⁹⁰Sr beta source at different doses were measured. The double perovskite phosphors under study showed a linear dose–response with increasing beta dose, ranging from 1 Gy to 10 Gy. Trapping parameters of the TL glow curves were determined using Chen's peak shape method and computerized glow curve deconvolution (CGCD). CGCD fitting of the TL glow curves revealed that it was consisted of three major peaks and followed second-order kinetics. The estimated activation energies were determined using different methods and were comparable and significant.     

The effects of external bending moments on lumbar muscle force distribution

A detailed biomechanical model of the low-back musculature that predicts muscle-force distribution in response to external loading is presented. The paper shows that the class of loading tasks that involve an erect posture and an arbitrary load placed on the upper limbs can be described as a loading plane whose axes are the flexion and lateral bending moments. Under these conditions, the individual muscle forces are described as a three-dimensional surface defined by the loading plane and termed the muscle activity surface (MAS). The MAS and the loading plane intersect along the switching curve which separates the load combinations that activate the muscle from those that do not. The paper suggests the existence of a recruitment order of low back muscles in response to external loads and presents a comprehensive framework for examining earlier studies that used EMG measurements to validate physiological and mechanical predictions.     

Nontimber forest product extraction, utilization and valuation: A case study from the Nilgiri Biosphere reserve, southern India

We evaluated the diversity, social, and economic aspects of nontimber forest product (NTFP) collection in the Nilgiri Biosphere Reserve (NBR), in southern India. The NBR is a region known for its floral andfaunal diversity, as well as an area with increasing human pressure. Fifty to 75% of the households (HH) in rural areas gather a diversity of forest products. Dominant NTFPs contributed 25–60% of the average annual per capita household income from NTFPs. The mean annual per capita household income from NTFPs ranges between Rs. 134 and Rs. 4955. The mean annual income per hectare ranges from Rs. 93 in the montane zone to Rs. 3780 in the moist deciduous. NTFPs contribute 15–50% of the annual per capita income of rural households. Ethnicity plays an important role in the collection of NTFPs and ethnic tribes derive a large proportion of their annual per capita income from NTFPs.     

Pulse radiolytic measurement of redox potentials: the tyrosine and tryptophan radicals

With the technique of pulse radiolysis we have measured the redox midpoint potentials of the tryptophan side chain neutral indolyl radical (1.05 +/- 0.01 V vs NHE, pH 7.0 and 25 degrees C) and the tyrosine side chain neutral phenoxy radical (0.94 +/- 0.01 vs NHE, pH 7.0 and 25 degrees C). These potentials were obtained by using a variety of inorganic reference compounds in both kinetic and equilibrium protocols. We compare these results with others already in the literature, and we also present data useful in establishing a pulse radiolysis redox reference scale over the range 0.42-1.28 V.     

Comparative analysis of surface components of adult, micro-filariae and infective larvae of Brugia malayi

A comparative analysis of surface proteins of adult, microfilariae and infective larvae of Brugia malayi, the human filarial parasite, has been carried out using IODOGEN (1,3,4,6-tetrachloro-3,alpha 6 alpha-diphenyl-glycoluril) and lactoperoxidase methods. SDS-polyacrylamide gel electrophoretic and autoradiographic analyses revealed the presence of 9 proteins (15-200 kDa) in adults, while microfilariae and infective larvae showed 8 and 6 proteins (15-120 kDa), respectively. The pattern of proteins radiolabelled by IODOGEN method was very similar to that of proteins labelled by the lactoperoxidase method. Since these proteins are released by the protease treatment of whole parasites, they are likely to be present on the surface of the parasite.