Synthesis and enantiopreferential DNA-binding profile of late 3d transition metal R- and S-enantiomeric complexes derived from N,N-bis-(1-benzyl-2-ethoxyethane): Validation of R-enantiomer of copper(II) complex as a human topoisomerase II inhibitor

To evaluate the biological preference of chiral drug candidates for molecular target DNA, new potential metal‐based chemotherapeutic agents 1 , 1a , 1b , 2 , 2a , 2b , 3 , 3a , 3b of late 3d transition metals Ni(II), Cu(II), and Zn(II), respectively, derived from (R)‐ and (S)‐2‐amino‐2‐phenylethanol with  CH₂ CH₂ linker were synthesized and thoroughly characterized. Interaction studies of 1 , 1a , 1b , 2 , 2a , 2b , 3 , 3a , 3b with calf thymus DNA in Tris buffer were studied by electronic absorption titrations, luminescence titrations, cyclic voltammetry, and circular dichroism. The results reveal that the extent of DNA binding of R‐enantiomer of copper 1a was highest in comparison to rest of the complexes via electrostatic interaction mode. The nuclease activity of 1a , 1b with supercoiled pBR322 DNA was further examined by gel electrophoresis, which reveals that complex 1a exhibits a remarkable DNA cleavage activity (concentration dependent) with pBR322DNA, and the cleavage activity of both enantiomers of complex 1 was significantly enhanced in the presence of activators. The activating efficiency follows the order Asc > H₂O₂ > MPA for 1a , and reverse order was observed for 1b , because of the differences in enantioselectivity and conformation. Further, it was observed that cleavage reaction involves singlet oxygen species and superoxide radicals via oxidative cleavage mechanism. In addition, complex 1a exhibits significant inhibitory effects on the topoisomerase II (topo II) activity at a very low concentration ∼24 μM, which suggest that complex 1a is indeed catalytic inhibitor or (poison) of human topo II. Chirality 2011 © 2011 Wiley‐Liss, Inc.     

Structural investigation of CDCA3‐Cdh1 protein–protein interactions using in vitro studies and molecular dynamics simulation

The anaphase‐promoting complex/cyclosome (APC/C) ubiquitin ligase and its cofactor, Cdh1, regulate the expression of several cell‐cycle proteins and their functions during mitosis. Levels of the protein cell division cycle‐associated protein 3 (CDCA3), which is functionally required for mitotic entry, are regulated by APC/C^Cdh1. CDCA3 is an intrinsically disordered protein and contains both C‐terminal KEN box and D‐box recognition motifs, enabling binding to Cdh1. Our previous findings demonstrate that CDCA3 has a phosphorylation‐dependent non‐canonical ABBA‐like motif within the linker region bridging these two recognition motifs and is required for efficient binding to Cdh1. Here, we sought to identify and further characterize additional residues that participate within this ABBA‐like motif using detailed in vitro experiments and in silico modeling studies. We identified the role of H‐bonds, hydrophobic and ionic interactions across the CDCA3 ABBA‐like motif in the linker region between KEN and D‐box motifs. This linker region adopts a well‐defined structure when bound to Cdh1 in the presence of phosphorylation. Upon alanine mutation, the structure of this region is lost, leading to higher flexibility, and alteration in affinities due to binding to alternate sites on Cdh1. Our findings identify roles for the anchoring residues in the non‐canonical ABBA‐like motif to promote binding to the APC/C^Cdh1 and regulation of CDCA3 protein levels.     

Stability Performance of Inductively Coupled Plasma Mass Spectrometry-Phenotyped Kernel Minerals Concentration and Grain Yield in Maize in Different Agro-Climatic Zones

Deficiency of iron and zinc causes micronutrient malnutrition or hidden hunger, which severely affects ~25% of global population. Genetic biofortification of maize has emerged as cost effective and sustainable approach in addressing malnourishment of iron and zinc deficiency. Therefore, understanding the genetic variation and stability of kernel micronutrients and grain yield of the maize inbreds is a prerequisite in breeding micronutrient-rich high yielding hybrids to alleviate micronutrient malnutrition. We report here, the genetic variability and stability of the kernel micronutrients concentration and grain yield in a set of 50 maize inbred panel selected from the national and the international centres that were raised at six different maize growing regions of India. Phenotyping of kernels using inductively coupled plasma mass spectrometry (ICP-MS) revealed considerable variability for kernel minerals concentration (iron: 18.88 to 47.65 mg kg^–1; zinc: 5.41 to 30.85 mg kg^–1; manganese: 3.30 to17.73 mg kg^–1; copper: 0.53 to 5.48 mg kg^–1) and grain yield (826.6 to 5413 kg ha^–1). Significant positive correlation was observed between kernel iron and zinc within (r = 0.37 to r = 0.52, p < 0.05) and across locations (r = 0.44, p < 0.01). Variance components of the additive main effects and multiplicative interactions (AMMI) model showed significant genotype and genotype × environment interaction for kernel minerals concentration and grain yield. Most of the variation was contributed by genotype main effect for kernel iron (39.6%), manganese (41.34%) and copper (41.12%), and environment main effects for both kernel zinc (40.5%) and grain yield (37.0%). Genotype main effect plus genotype-by-environment interaction (GGE) biplot identified several mega environments for kernel minerals and grain yield. Comparison of stability parameters revealed AMMI stability value (ASV) as the better representative of the AMMI stability parameters. Dynamic stability parameter GGE distance (GGED) showed strong and positive correlation with both mean kernel concentrations and grain yield. Inbreds (CM-501, SKV-775, HUZM-185) identified from the present investigation will be useful in developing micronutrient-rich as well as stable maize hybrids without compromising grain yield.     

IL-15 can signal via IL-15Rα, JNK, and NF-κB to drive RANTES production by myeloid cells

IL-15 plays many important roles within the immune system. IL-15 signals in lymphocytes via trans presentation, where accessory cells such as macrophages and dendritic cells present IL-15 bound to IL-15Rα in trans to NK cells and CD8(+) memory T cells expressing IL-15/IL-2Rβ and common γ chain (γ(c)). Previously, we showed that the prophylactic delivery of IL-15 to Rag2(-/-)γ(c)(-/-) mice (mature T, B, and NK cell negative) afforded protection against a lethal HSV-2 challenge and metastasis of B16/F10 melanoma cells. In this study, we demonstrated that in vivo delivery of an adenoviral construct optimized for the secretion of human IL-15 to Rag2(-/-)γ(c)(-/-) mice resulted in significant increases in spleen size and cell number, leading us to hypothesize that IL-15 signals differently in myeloid immune cells compared with lymphocytes, for which IL-15/IL-2Rβ and γ(c) expression are essential. Furthermore, treatment with IL-15 induced RANTES production by Rag2(-/-)γ(c)(-/-) bone marrow cells, but the presence of γ(c) did not increase bone marrow cell sensitivity to IL-15. This IL-15-mediated RANTES production by Rag2(-/-)γ(c)(-/-) bone marrow cells occurred independently of the IL-15/IL-2Rβ and Jak/STAT pathways and instead required IL-15Rα signaling as well as activation of JNK and NF-κB. Importantly, we also showed that the trans presentation of IL-15 by IL-15Rα boosts IL-15-mediated IFN-γ production by NK cells but reduces IL-15-mediated RANTES production by Rag2(-/-)γ(c)(-/-) myeloid bone marrow cells. Our data clearly show that IL-15 signaling in NK cells is different from that of myeloid immune cells. Additional insights into IL-15 biology may lead to novel therapies aimed at bolstering targeted immune responses against cancer and infectious disease.     

Role of Triacontanol in Counteracting the Ill Effects of Salinity in Plants: A Review

Soil salinity is one among the common environmental threats to agriculture. It adversely affects the physio-biochemical processes of plants that eventually lead to the reduction in growth, development and crop productivity. To cope with such adverse conditions, plants develop certain internal mechanisms, but under severe conditions these mechanisms fail to tolerate the salt stress. To overcome this problem, various strategies have been employed that help plants to mitigate salinity effects. Among the various strategies, the application of plant growth regulators (PGRs) has gained significant attention to induce salt tolerance in plants. A number of PGRs have been used so far. Among these, triacontanol (TRIA), a new PGR is gaining a lot of importance to enhance the plant growth, productivity and salinity tolerance in different crops. The utility of TRIA is dependent on its applied concentration. Its lower concentrations generally alleviate the salinity effects. However, the knowledge of its biosynthesis, signalling and its role particularly to mitigate salinity effect remains scanty. In the present article, the focus has been given on the role of exogenous applications of TRIA in the regulation of physio-biochemical characteristics especially plant growth, photosynthesis, nutrient acquisition, oxidative stress, antioxidant systems, compatible solutes, yield attributes and its mode of action in plants under salinity conditions. The salient features of the review may provide new insights on the role of TRIA in countering the ill effect of salinity in different crop plants.

     

Development of β-Carotene Rich Maize Hybrids through Marker-Assisted Introgression of β-carotene hydroxylase Allele

Development of vitamin A-rich cereals can help in alleviating the widespread problem of vitamin A deficiency. We report here significant enhancement of kernel β-carotene in elite maize genotypes through accelerated marker-assisted backcross breeding. A favourable allele (543 bp) of the β-carotene hydroxylase (crtRB1) gene was introgressed in the seven elite inbred parents, which were low (1.4 µg/g) in kernel β-carotene, by using a crtRB1-specific DNA marker for foreground selection. About 90% of the recurrent parent genome was recovered in the selected progenies within two backcross generations. Concentration of β-carotene among the crtRB1-introgressed inbreds varied from 8.6 to 17.5 µg/g - a maximum increase up to 12.6-fold over recurrent parent. The reconstituted hybrids developed from improved parental inbreds also showed enhanced kernel β-carotene as high as 21.7 µg/g, compared to 2.6 µg/g in the original hybrid. The reconstituted hybrids evaluated at two locations possessed similar grain yield to that of original hybrids. These β-carotene enriched high yielding hybrids can be effectively utilized in the maize biofortification programs across the globe.     

Platanic Acid-Aryl Enones as Potential Anticancer Compounds: Synthesis and Biological Profiling against Breast,Prostate and Lung Cancer Cell Lines

A series of rationally designed platanic acid-based compounds derived from naturally occurring betulinic acid were synthesized through a sequence of Lemieux-Johnson oxidation and Aldol condensation reaction. All the compounds were screened for cytotoxicity against a panel of human cancer and normal cell lines using MTT assay. From the biological data, it was observed that some of these semi-synthetic congeners exhibited potent biological profiles compared to platanic acid. One of the compounds with the p-tolyl substitution was found to be most active in this study, and its cytotoxicity against two of the cell lines, MDA-MB 231 and A-549 were in tune with the standard compound, 5-fluorouracil.     

An investigation of enumeration and DNA partitioning in Bacillus subtilis L-form bacteria

R.N. WATERHOUSE, E.J. ALLAN, F. AMIJEE, V.J. UNDRILL AND L.A. GLOVER. 1994. Cell numbers of two morphogenic forms of Bacillus subtilis (the cell-walled parental and the derived stable cell wall-deficient L-form) have been compared by two methods: DNA hybridization (i.e. deduced genome numbers) and viable cell counts (i.e. number of colony-forming units (cfu)). The DNA hybridization method was shown to be a reliable and reproducible method for estimating genome numbers. Comparison of different L-form populations showed that the two methods of enumeration gave different values, with the deduced genome numbers much higher (by several orders of magnitude) than cell numbers deduced from viable cell counts. In contrast, when a culture of the cell-walled form was enumerated, the discrepancy between the two methods was low (by a factor of about 6) The combination of a high number of L-form genomes detected by DNA hybridization and a relatively low number of cfu was thought to be a consequence of a diminished co-ordination between the DNA replication and cell division processes in L-form bacteria. This suggestion was further substantiated by assessing the stability of plasmid pPL608 in a transformed B. subtilis L-form cell line, where even in the presence of continued kanamycin selection, 25% of the population lost kanamycin resistance. The results are discussed with particular reference to cell division in cell wall-deficient, stable L-form bacteria.     

Antileishmanial potential of fused 5-(pyrazin-2-yl)-4H-1,2,4-triazole-3-thiols: Synthesis,biological evaluations and computational studies

A series of newer 1,2,4-triazole-3-thiol derivatives 5(a–m) and 6(a–i) containing a triazole fused with pyrazine moiety of pharmacological significance have been synthesized. All the synthesized compounds were screened for their in vitro antileishmanial and antioxidant activities. Compounds 5f (IC₅₀ = 79.0 µM) and 6f (IC₅₀ = 79.0 µM) were shown significant antileishmanial activity when compared with standard sodium stibogluconate (IC₅₀ = 490.0 µM). Compounds 5b (IC₅₀ = 13.96 µM) and 6b (IC₅₀ = 13.96 µM) showed significant antioxidant activity. After performing molecular docking study and analyzing overall binding modes it was found that the synthesized compounds had potential to inhibit L. donovani pteridine reductase 1 enzyme. In silico ADME and metabolic site prediction studies were also held out to set an effective lead candidate for the future antileishmanial and antibacterial drug discovery initiatives.