Studies on collagen-tannic acid-collagenase ternary system: Inhibition of collagenase against collagenolytic degradation of extracellular matrix component of collagen

We report the detailed studies on the inhibitory effect of tannic acid (TA) on Clostridium histolyticum collagenase (ChC) activity against degradation of extracellular matrix component of collagen. The TA treated collagen exhibited 64% resistance against collagenolytic hydrolysis by ChC, whereas direct interaction of TA with ChC exhibited 99% inhibition against degradation of collagen and the inhibition was found to be concentration dependant. The kinetic inhibition of ChC has been deduced from the extent of hydrolysis of N-[3-(2-furyl) acryloyl]-Leu-Gly-Pro-Ala (FALGPA). This data provides a selective competitive mode of inhibition on ChC activity seems to be influenced strongly by the nature and structure of TA. TA showed inhibitor activity against the ChC by molecular docking method. This result demonstrated that TA containing digalloyl radical possess the ability to inhibit the ChC. The inhibition of ChC in gaining new insight into the mechanism of stabilization of collagen by TA is discussed.     

Synthesis of novel heterobimetallic copper(I) hydrazone Schiff base complexes: a comparative study on the effect of heterocyclic hydrazides towards interaction with DNA/protein, free radical scavenging and cytotoxicity

Two new copper(I) hydrazone complexes have been synthesised from bivalent copper precursor [CuCl(2)(PPh(3))(2)] and ferrocene containing bidentate hydrazone ligands HL(1) (1) or HL(2) (2). Based on the elemental analyses and spectroscopic data, the complexes are best formulated as [CuL(1)(PPh(3))(2)] (3) and [CuL(2)(PPh(3))(2)] (4) of the monovalent copper ion. Solid state structures of ligand 2 and its corresponding complex 4 were also determined. The DNA/albumin interactions of all the synthesised compounds were investigated using absorption, emission and synchronous fluorescence studies. Further, antioxidant properties of all the compounds have also been checked against ABTS, O(2)(-) and OH radicals. Additionally, the in vitro cytotoxic activity of compounds 1-4 was assessed using tumour (HeLa, A431) and non-tumour (NIH 3T3) cell lines.     

Re-irradiation after stereotactic body radiotherapy for spine metastases from hepatocellular carcinoma: a case report

Modern radiotherapy machines with refinements in planning software and image-guidance apparatuses have made stereotactic body radiotherapy (SBRT) more widely available as an effective tool in the management of spine metastases. In conventional palliative radiotherapy, the aim has traditionally been pain relief and short-term local control. In contrast, SBRT aims to deliver an ablative dose to enhance local control, with a smaller number of fractions while sparing the organs at risk (OAR), especially the spinal cord. Recently, trials have asserted the role of spine SBRT as an effective modality for durable local control, in addition to achieving pain relief. The quality of evidence for spine SBRT data is maturing, while prospective published trials on re-irradiation SBRT in spine remain sparse. The purpose of the present case report is to share the challenges faced while salvaging a dorsal spine metastasis and ablating a new right adrenal metastatic lesion in proximity of the transplanted liver.     

Nutrient uptake by paddy during the main three stages of growth

Summary Uptake of mineral nutrients and production of carbohydrates by paddy during the vegetative, the reproductive, and the ripening stage of growth were determined in a pot experiment.From 59 to 84 per cent of the nutrients present in the ripe plants were absorbed between tillering and flowering. More than 90 per cent of the N and K, 80 per cent of the P and Ca, and 65 per cent of the Mg were absorbed prior to flowering, and the remainder after heading.More than 60 per cent of the carbohydrates present in the ripe stage was produced after flowering.     

Activation of c-Kit in dendritic cells regulates T helper cell differentiation and allergic asthma

Dendritic cells (DCs) are integral to the differentiation of T helper cells into T helper type 1 T(H)1, T(H)2 and T(H)17 subsets. Interleukin-6 (IL-6) plays an important part in regulating these three arms of the immune response by limiting the T(H)1 response and promoting the T(H)2 and T(H)17 responses. In this study, we investigated pathways in DCs that promote IL-6 production. We show that the allergen house dust mite (HDM) or the mucosal adjuvant cholera toxin promotes cell surface expression of c-Kit and its ligand, stem cell factor (SCF), on DCs. This dual upregulation of c-Kit and SCF results in sustained signaling downstream of c-Kit, promoting IL-6 secretion. Intranasal administration of antigen into c-Kit-mutant mice or neutralization of IL-6 in cultures established from the lung-draining lymph nodes of immunized wild-type mice blunted the T(H)2 and T(H)17 responses. DCs lacking functional c-Kit or those unable to express membrane-bound SCF secreted lower amounts of IL-6 in response to HDM or cholera toxin. DCs expressing nonfunctional c-Kit were unable to induce a robust T(H)2 or T(H)17 response and elicited diminished allergic airway inflammation when adoptively transferred into mice. Expression of the Notch ligand Jagged-2, which has been associated with T(H)2 differentiation, was blunted in DCs from c-Kit-mutant mice. c-Kit upregulation was specifically induced by T(H)2- and T(H)17-skewing stimuli, as the T(H)1-inducing adjuvant, CpG oligodeoxynucleotide, did not promote either c-Kit or Jagged-2 expression. DCs generated from mice expressing a catalytically inactive form of the p110delta subunit of phosphatidylinositol-3 (PI3) kinase (p110(D910A)) secreted lower amounts of IL-6 upon stimulation with cholera toxin. Collectively, these results highlight the importance of the c-Kit-PI3 kinase-IL-6 signaling axis in DCs in regulating T cell responses.     

MtDNA haplogroup analysis of black Brazilian and sub-Saharan populations: implications for the Atlantic slave trade

Seventy individuals from two African and four black Brazilian populations were studied for the first hypervariable segment of mtDNA. To delineate a more complete phylogeographic scenario of the African mtDNA haplogroups in Brazil and to provide additional information on the nature of the Atlantic slave trade, we analyzed our data together with previously published data. The results indicate different sources of African slaves for the four major Brazilian regions. In addition, the data revealed patterns that differ from those expected on the basis of historical registers, thus suggesting the role of ethnic sex differences in the slave trade.     

Fitting periplasmic membrane fusion proteins to inner membrane transporters: mutations that enable Escherichia coli AcrA to function with Pseudomonas aeruginosa MexB

AcrAB-TolC from Escherichia coli is a multidrug efflux complex capable of transenvelope transport. In this complex, AcrA is a periplasmic membrane fusion protein that establishes a functional connection between the inner membrane transporter AcrB of the RND superfamily and the outer membrane channel TolC. To gain insight into the mechanism of the functional association between components of this complex, we replaced AcrB with its close homolog MexB from Pseudomonas aeruginosa. Surprisingly, we found that AcrA is promiscuous and can form a partially functional complex with MexB and TolC. The chimeric AcrA-MexB-TolC complex protected cells from sodium dodecyl sulfate, novobiocin, and ethidium bromide but failed with other known substrates of MexB. We next identified single and double mutations in AcrA and MexB that enabled the complete functional fit between AcrA, MexB, and TolC. Mutations in either the α-helical hairpin of AcrA making contact with TolC or the β-barrel domain lying on MexB improved the functional alignment between components of the complex. Our results suggest that three components of multidrug efflux pumps do not associate in an “all-or-nothing” fashion but accommodate a certain degree of flexibility. This flexibility in the association between components affects the transport efficiency of RND pumps.     

Molecular Modeling of Disease Causing Mutations in Domain C1 of cMyBP-C

Cardiac myosin binding protein-C (cMyBP-C) is a multi-domain (C0–C10) protein that regulates heart muscle contraction through interaction with myosin, actin and other sarcomeric proteins. Several mutations of this protein cause familial hypertrophic cardiomyopathy (HCM). Domain C1 of cMyBP-C plays a central role in protein interactions with actin and myosin. Here, we studied structure-function relationship of three disease causing mutations, Arg177His, Ala216Thr and Glu258Lys of the domain C1 using computational biology techniques with its available X-ray crystal structure. The results suggest that each mutation could affect structural properties of the domain C1, and hence it’s structural integrity through modifying intra-molecular arrangements in a distinct mode. The mutations also change surface charge distributions, which could impact the binding of C1 with other sarcomeric proteins thereby affecting contractile function. These structural consequences of the C1 mutants could be valuable to understand the molecular mechanisms for the disease.     

O-GlcNAcylation of αB-crystallin regulates its stress-induced translocation and cytoprotection

Under normal conditions, the ubiquitously expressed αB-crystallin functions as a chaperone. αB-crystallin has been implicated in a variety of pathologies, consistent with a build-up of protein aggregates, such as neuromuscular disorders, myofibrillar myopathies, and cardiomyopathies. αB-crystallins’ cardioprotection is partially attributed to its translocation and binding to cytoskeletal elements in response to stress. The triggers for this translocation are not clearly understood. In the heart, αB-crystallin undergoes at least three significant post-translational modifications: phosphorylation at ser-45 and 59 and O-GlcNAcylation (O-linked attachment of the monosaccharide β-N-acetyl-glucosamine) at thr-170. Whether phosphorylation status drives translocation remains controversial. Therefore, we evaluated the role of αB-crystallins’ O-GlcNAcylation in its stress-induced translocation and cytoprotection in cardiomyocytes under stress. Immunoblotting and precipitation experiments with anti-O-GlcNAc antibody (CTD110.6) and glycoprotein staining (Pro-Q Emerald) both demonstrate robust stress-induced O-GlcNAcylation of αB-crystallin. A non-O-GlcNAcylatable αB-crystallin mutant (αB-T170A) showed diminished translocation in response to heat shock and robust phosphorylation at both ser-45 and ser-59. Cell survival assays show a loss of overexpression-associated cytoprotection with the non-glycosylatable mutant to multiple stresses. While ectopic expression of wild-type αB-crystallin strongly stabilized ZsProSensor, a fusion protein rapidly degraded by the proteasome, the non-O-GlcNAcylatable version did not. Therefore, we believe the O-GlcNAcylation of αB-crystallin is a dynamic and important regulator of both its localization and function.