The effect of histidine on the structure and antitumor activity of metal-5-halouracil complexes

The ternary complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) ions with 5-halouracils, viz., 5-fluorouracil (5FU), 5-chlorouracil (5ClU), and 5-bromouracil (5BrU), and the biologically important ligand L-histidine (HISD) have been synthesized and characterized by elemental analysis, conductance measurements, infrared spectra, electronic spectra, and magnetic moment (room temperature) measurements. On the basis of these studies, the structures of the complexes have been proposed. All these ternary complexes were screened for their antitumor activity against Dalton's lymphoma in C3H/He mice. It was found that only Mn(II)-5BrU-HISD, Co(II)-5BrU-HISD, Cu(II)-5ClU-HISD, Cu(II)-5BrU-HISD, Zn(II)-5FU-HISD, and Zn(II)-5BrU-HISD complexes have significant antitumor activity with T/C greater than 125% (where T and C represent mean lifespan of treated mice and control mice respectively). The Mn(II)-5FU-HISD, Co(II)-5FU-HISD, Co(II)-5ClU-HISD, Ni(II)-5ClU-HISD, Ni(II)-5BrU-HISD, and Zn(II)-5ClU-HISD complexes are also effective antitumor agents, with T/C greater than 115%. The complexes that showed effective antitumor action in vivo were also found to inhibit 3H-thymidine incorporation (DNA replication) in Dalton's lymphoma cells in vitro.     

Transfer of Brassica tournefartii (TT) genes to allotetraploid oilseed Brassica species (B. juncea AABB, B. napus AACC, B. carinata BBCC): homoeologous pairing is more pronounced in the three-genome hybrids (TACC, TBAA, TCAA, TCBB) as compared to allodiploids (TA, TB, TC)

For the transfer of genes from B. tournefortii (TT) to the allotetraploid oilseed brassicas, B. juncea AABB, B. carinata BBCC and B. napus AACC, B. tournefortii was first crossed with the three basic diploid species, B. campestris (AA), B. nigra (BE) and B. oleracea (CC), to produce the allodiploids TA, TB and TC. These were tetraploidized by colchicine treatment to produce the allotetraploids TTAA, TTBB and TTCC, which were further crossed with B. juncea and B. napus to produce three-genome hybrids with substitution-type genomic configurations: TACC, TBAA and TCAA. These hybrids along with another hybrid TCBB produced earlier, the three allodiploids, their allotetraploids and the four diploid parent species were studied for their male meiotic behaviour. The diploid parent and the allotetraploids (TTAA, TTBB and TTCC) showed regular meiosis although the pollen viability was generally low in the allotetraploids. In the allodiploids (TA, TB and TC) only some end-to-end associations were observed without any clearly discernible chiasmata or exchange points. Chromosomes involved in end-to-end associations were randomly distributed at the metaphase/anaphase-I stages. In contrast, the three-genome hybrids (TACC, TBAA, TCAA and TCBB) showed normal bivalents whose number exceeded the expected bivalent values. Bivalents arising out of homoeologous pairing were indistinguishable from normal pairs by their disjunction pattern but could be distinguished on the basis of the heteromorphy of the homoeologous chromosomes. The three-genome hybrids could be backcrossed to allotetraploid oilseed brassicas as they had some fertility. In contrast, the allodiploids could neither be selfed nor back-crossed. On the basis of their meiotic stability, in terms of more pronounced homoeologous pairing and fertility for backcrossing, the three-genome configurations provide the best possible situation for the introgression of alien genes from the secondary gene pool to the allotetraploid oilseed crops B. juncea, B. napus and B. carinata.     

Somatic hybrids with substitution type genomic configuration TCBB for the transfer of nuclear and organelle genes from Brassica tournefortii TT to allotetraploid oilseed crop B. carinata BBCC

Oilseed crop Brassica carinata BBCC is a natural allotetraploid of diploid species B. nigra BB and B. oleracea CC. To transfer the nuclear and organelle genes in a concerted manner from an alien species, B. tournefortii TT, to B. carinata, we produced somatic hybrids with genomic configuration TCBB using B. nigra and B. oleracea stocks that carried selectable marker genes. B. tournefortii TT was sexually crossed with hygromycin-resistant B. oleracea CC. Protoplasts isolated from shoot cultures of hygromycin-resistant F₁ hybrids of B. tournefortiixB. oleracea TC were fused with protoplasts of kanamycin-resistant B. nigra BB. In two different fusion experiments 80 colonies were obtained through selection on media containing both hygromycin and kanamycin. Of these, 39 colonies regenerated into plants. Analysis of 15 regenerants by random amplified polymorphic DNA (RAPD) markers showed the presence of all three genomes, thereby confirming these to be true hybrids. Restriction fragment length polymorphism (RFLP) analysis of organelle genomes with heterologous chloroplast (cp)and mitochondrial (mt) DNA probes showed that the chloroplast genome was inherited from either of the two parents while mitochondrial genomes predominantly showed novel configurations due to either rearrangements or intergenomic recombinations. We anticipate that the TCBB genomic configuration will provide a more conducive situation for recombination between the T and C genomes during meiosis than the TTCCBB or TCCBB type configurations that are usually produced for alien gene transfer. The agronomic aim of producing TCBB hybrids is to transfer mitochondrial genes conferring cytoplasmic male sterility and nuclear genes for fertility restoration from B. tournefortii to B. carinata.     

Microbial biofilm ecology,in silico study of quorum sensing receptor-ligand interactions and biofilm mediated bioremediation

Archives of Microbiology - Biofilms are structured microbial communities of single or multiple populations in which microbial cells adhere to a surface and get embedded in extracellular polymeric...     

Microsatellite Analysis of Genetic Population Structure of Zebu Cattle (Bos indicus) Breeds from North-Western Region of India

The present study aims to understand the existing genetic diversity and structure of six native cattle breeds (Rathi, Tharparkar, Nagori, Mewati, Gir, and Kankrej) adapted to the north-western arid and semi-arid region of India based on microsatellite loci. Various diversity estimates, mean number of alleles (12.84); effective number of alleles (5.02); gene diversity (0.769), and observed heterozygosity (0.667) reflected the existence of substantial within-breed diversity in all the investigated cattle breeds. Mean estimates of F-statistics: F_IT = 0.144 ± 0.023, F_IS = 0.071 ± 0.021, and F_ST = 0.078 ± 0.014 were significantly different from zero (P < 0.05). The interbreed relationships indicated moderate level of breed differentiation between the six cattle breeds with least differentiation between Kankrej-Mewati pair. The phylogeny structuring further supported close grouping of Kankrej and Mewati breeds. Correspondence analysis plotted Rathi, Tharparkar, and Gir individuals into three separate areas of multivariate space; whereas, Kankrej, Mewati, and Nagori cattle showed low breed specific clustering. This reflected the existence of discrete genetic structure for Tharparkar, Rathi, and Gir, the prominent dairy breeds of the region; whereas, admixture was observed for Kankrej, Mewati, and Nagori individuals.     

Surface Acoustic Waves Enhance Neutrophil Killing of Bacteria

Biofilms are structured communities of bacteria that play a major role in the pathogenicity of bacteria and are the leading cause of antibiotic resistant bacterial infections on indwelling catheters and medical prosthetic devices. Failure to resolve these biofilm infections may necessitate the surgical removal of the prosthetic device which can be debilitating and costly. Recent studies have shown that application of surface acoustic waves to catheter surfaces can reduce the incidence of infections by a mechanism that has not yet been clarified. We report here the effects of surface acoustic waves (SAW) on the capacity of human neutrophils to eradicate S. epidermidis bacteria in a planktonic state and within biofilms. Utilizing a novel fibrin gel system that mimics a tissue-like environment, we show that SAW, at an intensity of 0.3 mW/cm², significantly enhances human neutrophil killing of S. epidermidis in a planktonic state and within biofilms by enhancing human neutrophil chemotaxis in response to chemoattractants. In addition, we show that the integrin CD18 plays a significant role in the killing enhancement observed in applying SAW. We propose from out data that this integrin may serve as mechanoreceptor for surface acoustic waves enhancing neutrophil chemotaxis and killing of bacteria.     

Energy deprivation by silibinin in colorectal cancer cells

Small molecules with the potential to initiate different types of programmed cell death could be useful ‘adjunct therapy’ where current anticancer modalities fail to generate significant activity due to a defective apoptotic machinery or resistance of cancer cells to the specific death mechanism induced by that treatment. The current study identified silibinin, for the first time, as one such natural agent, having dual efficacy against colorectal cancer (CRC) cells. First, silibinin rapidly induced oxidative stress in CRC SW480 cells due to reactive oxygen species (ROS) generation with a concomitant dissipation of mitchondrial potential (ΔΨ_m) and cytochrome c release leading to mild apoptosis as a biological effect. However, with increased exposure to silibinin, cytoplasmic vacuolization intensified within the cells followed by sequestration of the organelles, which inhibits the further release of cytochrome c. Interestingly, this decrease in apoptotic response correlated with increased autophagic events as evidenced by tracking the dynamics of LC3-II within the cells. Mechanistic studies revealed that silibinin strongly inhibited PIK3CA-AKT–MTOR but activated MAP2K1/2-MAPK1/3 pathways for its biological effects. Corroborating these effects, endoplasmic reticulum stress was generated and glucose uptake inhibition as well as energy restriction were induced by silibinin, thus, mimicking starvation-like conditions. Further, the cellular damage to tumor cells by silibinin was severe and irreparable due to sustained interference in essential cellular processes such as mitochondrial metabolism, phospholipid and protein synthesis, suggesting that silibinin harbors a deadly ‘double-edged sword’ against CRC cells thereby further advocating its clinical effectiveness against this malignancy.     

Differentiation dynamics of mammary epithelial stem cells from Korean holstein dairy cattle under ECM-free conditions

The “stem cells” are commonly defined as “cells capable of self-renewal through replication and differentiating into specific lineages”. The mammary gland contains functional stem/progenitor cells. The current study was planned with the objectives to study the differentiation dynamics of Korean Holstein mammary epithelial stem cells (KHMESCs) under the optimum culture conditions. Lineage negative KHMESCs isolated from mammary tissue of lactating cows have shown the typical differentiation dynamics with formation of lobulo–alveolar structures in in vitro culture. This suggests the existence of bipotential mammary epithelial stem cells in the mammary gland. The strong mRNA expression of pluripotency factors indicates stemness, whereas expression of milk protein genes and epithelial cell-specific gene indicate their differentiation capabilities. Further, immunostaining results have shown the differentiation capabilities of KHMESCs into both luminal and basal lineages under the extracellular matrix (ECM, matrigel) free environment. However, under matrigel, the differentiation process was comparatively higher than without matrigel. Immunostaining results also suggested that differentiated cells could secrete milk proteins such as β-casein. To our knowledge, these data represent the first report on the differentiation dynamics and establishment of mammary epithelial stem cells from Korean Holstein with typical stemness properties. It was observed that isolated KHMESCs had normal morphology, growth pattern, differentiation ability, cytogenetic and secretory activity even without ECM. Therefore, it is concluded that established KHMESCs could be used for further studies on Korean Holstein dairy cows related to lactation studies, as non-GMO animal bioreactors and stem cell-based management of bovine mastitis including post-mastitis damage.     

Morningness-eveningness preferences,learning approach and academic achievement of undergraduate medical students

ABSTRACT

Several studies have focused on determining the effect of chronotype and learning approach on academic achievement separately indicating that morning types have an academic advantage over the evening types and so have the deep learners over the surface learners. But, surprisingly none have assessed the possible relationship between chronotype and learning approach. So, the current study aimed to evaluate this association and their individual influence on academic performance as indicated by the Cumulative Grade Point Average (CGPA) as well as the effect of their interaction on academic performance. The study included 345 undergraduate medical students who responded to reduced Morningness-Eveningness Questionnaire and Biggs Revised Two-Factor Study Process Questionnaire. Morning types indulged in deep learning while evening types in surface learning. Morning and evening types did not differ on academic performance but deep learners had better academic outcomes than their counterparts. The interaction between chronotype and learning approach was significant on determining academic achievement. Our findings gave the impression that chronotype could have an impact on academic performance not directly but indirectly through learning approaches.