Neolithic phylogenetic continuity inferred from complete mitochondrial DNA sequences in a tribal population of Southern India

The subsequent human migrations that dispersed out of Africa, both prehistoric and historic and colonization of India by modern humans is unanimous, and phylogeny of major mitochondrial DNA haplogroups have played a key role in assessing the genetic origin of people of India. To address more such events, complete mitogenomes of 113 Melakudiya tribe of Southern India were sequenced and 46 individuals showed the presence of west Eurasian autochthonous haplogroups HV14 and U7. Phylogenetic analysis revealed two novel subclades HV14a1b and HV14a1b1 and sequences representing haplogroup U7 were included under previously described subclade U7a3a1a2* specific to India. Moreover, the present analysis on complete mtDNA reveals addition information of the spread and distribution of west Eurasian haplogroups in southern India, in tracing an unexplored genetic link between Melakudiya tribe with the people of Iranian Plateau, South Caucasus, and Central Asia. Coalescence ages of HV14 and U7a3a1a2* trees in the present study dates?~?16.1?±?4.3 and ~?13.4?±?5.6 kya respectively.     

Kinetic characterization of a T-state of Ascaris suum phosphofructokinase with heterotropic negative cooperativity by ATP eliminated.

The affinity analogue, 2',3'-dialdehyde ATP has been used to chemically modify the ATP-inhibitory site of Ascaris suum phosphofructokinase, thereby locking the enzyme into a less active T-state. This enzyme form has a maximum velocity that is 10% that of the native enzyme in the direction of fructose 6-phosphate (F6P) phosphorylation. The enzyme displays sigmoid saturation for the substrate fructose 6-phosphate (S0.5 (F6P) = 19 mM and nH = 2.2) at pH 6.8 and a hyperbolic saturation curve for MgATP with a Km identical to that for the native enzyme. The allosteric effectors, fructose 2,6-bisphosphate and AMP, do not affect the S0.5 for F6P but produce a slight (1.5- and 2-fold, respectively) V-type activation with Ka values (effector concentration required for half-maximal activation) of 0.40 and 0.24 mM, respectively. Their activating effects are additive and not synergistic. The kinetic mechanism for the modified enzyme is steady-state-ordered with MgATP as the first substrate and MgADP as the last product to be released from the enzyme surface. The decrease in V and V/K values for the reactants likely results from a decrease in the equilibrium constant for the isomerization of the E:MgATP binary complex, thus favoring an unisomerized form. The V and V/KF6P are pH dependent with similar pK values of about 7 on the acid side and 9.8 on the basic side. The microenvironment of the active site appears to be affected minimally as evidenced by the similarity of the pK values for the groups involved in the binding site for F6P in the modified and native enzymes.     

The 3-ketoacyl-CoA synthase WFL is involved in lateral organ development and cuticular wax synthesis in Medicago truncatula

Plant Molecular Biology - A 3-ketoacyl-CoA synthase involved in biosynthesis of very long chain fatty acids and cuticular wax plays a vital role in aerial organ development in M. truncatula....     

Purification of a recombinant histidine-tagged lactate dehydrogenase from the malaria parasite,Plasmodium vivax,and characterization of its properties

Lactate dehydrogenase (LDH) of the malaria parasite, Plasmodium vivax (Pv), serves as a drug target and immunodiagnostic marker. The LDH cDNA generated from total RNA of a clinical isolate of the parasite was cloned into pRSETA plasmid. Recombinant his-tagged PvLDH was over-expressed in E. coli Rosetta2DE3pLysS and purified using Ni²⁺-NTA resin giving a yield of 25–30 mg/litre bacterial culture. The recombinant protein was enzymatically active and its catalytic efficiency for pyruvate was 5.4 × 10⁸ min^?1 M^?1, 14.5 fold higher than a low yield preparation reported earlier to obtain PvLDH crystal structure. The enzyme activity was inhibited by gossypol and sodium oxamate. The recombinant PvLDH was reactive in lateral flow immunochromatographic assays detecting pan- and vivax-specific LDH. The soluble recombinant PvLDH purified using heterologous expression system can facilitate the generation of vivax LDH-specific monoclonals and the screening of chemical compound libraries for PvLDH inhibitors.     

Alpha-lipoic acid: an inhibitor of secretory phospholipase A2 with anti-inflammatory activity

Alpha-lipoic acid (ALA) and its reduced form dihydrolipoic acid (DHLA) are powerful antioxidants both in hydrophilic and lipophylic environments with diverse pharmacological properties including anti-inflammatory activity. The mechanism of anti-inflammatory activity of ALA and DHALA is not known. The present study describes the interaction of ALA and DHALA with pro-inflammatory secretory PLA(2) enzymes from inflammatory fluids and snake venoms. In vitro enzymatic inhibition of sPLA(2) from Vipera russellii, Naja naja and partially purified sPLA(2) enzymes from human ascitic fluid (HAF), human pleural fluid (HPF) and normal human serum (HS) by ALA and DHLA was studied using (14)C-oleate labeled Escherichia coli as the substrate. Biophysical interaction of ALA with sPLA(2) was studied by fluorescent spectral analysis and circular dichroism studies. In vivo anti-inflammatory activity was checked using sPLA(2) induced mouse paw edema model. ALA but not DHLA inhibited purified sPLA(2) enzymes from V. russellii, N. naja and partially purified HAF, HPF and HS in a dose dependent manner. This data indicated that ALA is critical for inhibition. IC(50) value calculated for these enzymes ranges from 0.75 to 3.0 microM. The inhibition is independent of calcium and substrate concentration. Inflammatory sPLA(2) enzymes are more sensitive to inhibition by ALA than snake venom sPLA(2) enzymes. ALA quenched the fluorescence intensity of sPLA(2) enzyme in a dose dependent manner. Apparent shift in the far UV-CD spectra of sPLA(2) with ALA indicated change in its alpha-helical confirmation and these results suggest its direct interaction with the enzyme. ALA inhibits the sPLA(2) induced mouse paw edema in a dose dependent manner and confirms the sPLA(2) inhibitory activity in vivo also. These data suggest that ALA may act as an endogenous regulator of sPLA(2) enzyme activity and suppress inflammatory reactions.     

Activation of α-secretase by curcumin-aminoacid conjugates

The extracellular senile plaques observed in Alzheimer's disease (AD) patients are mainly composed of amyloid peptides produced from the β-amyloid precursor protein (βAPP) by β- and γ-secretases. A third non-amyloidogenic α-secretase activity performed by the disintegrins ADAM10 and ADAM17 occurs in the middle of the amyloid-β peptide Aβ and liberates the large sAPPα neuroprotective fragment. Since the activation of α-secretase recently emerged as a promising therapeutic approach to treat AD, the identification of natural compounds able to trigger this cleavage is highly required. Here we describe new curcumin-based modified compounds as α-secretase activators. We established that the aminoacid conjugates curcumin-isoleucine, curcumin-phenylalanine and curcumin-valine promote the constitutive α-secretase activity and increase ADAM10 immunoreactivity. Strickingly, experiments carried out under conditions mimicking the PKC/muscarinic receptor-regulated pathway display different patterns of activation by these compounds. Altogether, our data identified new lead natural compounds for the future development of powerful and stable α-secretase activators and established that some of these molecules are able to discriminate between the constitutive and regulated α-secretase pathways.     

The siderophore ferricrocin produced by specific foliar endophytic fungi in vitro

Production of extracellular siderophores is typical for many plant-associated microbes, both mutualistic and antagonistic. Various strains of mycorrhizal fungi produce siderophores, and siderophore production by pathogenic fungi is typically associated with virulence. We analyzed extracellular siderophore production along with production of antibacterial and antioxidant compounds in foliar endophytic fungi of Scots pine (Pinus sylvestris L.) and Labrador tea (Rhododendron tomentosum Harmaja). The siderophore produced in vitro was ferricrocin, quantities ranging between 7.9 and 17.6 μg/l. Only the fungi with antibacterial activity produced ferricrocin and any well-known siderophores were not detected in the broths of antioxidant-producing fungi. Therefore, production of ferricrocin is typical for some, but not all foliar endophytic fungi. Ferricrocin was detected in the leaves of Labrador tea, which suggests that ferricrocin may play a role in vivo in the interaction between the endophyte and plant host.