DNA profiling of commercial chilli pepper (Capsicum annuum L.) varieties using random amplified polymorphic DNA (RAPD) markers

In the present study, genetic variability in 10 commercial chilli pepper varieties viz. Gemini, G-334, Agnirekha, Pusa jwala, Mangala, Black diamond, Sindura, Pusa jyothi, Badiga-2 and Teja (branch), cultivated in the local area of Andhra Pradesh State, India, using random amplified polymorphic DNA (RAPD) markers was examined. Out of thee RAPD markers used for screening 10 chilli pepper genotypes, DNA amplification was observed only with OPAB02; this primer produced monomorphic band in Gemini,G-334, Black diamond and Sindura and polymorphic bands in Agnirekha, Pusa jwala, Mangala, Pusa jyothi, Badiga-2 and Teja (Branch). Genetic variabilty in terms of DNA pattern produced in the above varieties could be used as a marker to distinguish between them. Dendrogram generated by OPAB02 primer showed that the 10 chilli pepper varieties could be grouped into four clusters. Average genetic similarity index revealed 100% similarity between varieties of first cluster, 50% similarity between varieties of second and fourth clusters and 32% genetic similarity between varieties of third cluster. UPGMA cluster analysis will be useful in chilli pepper breeding programmes and germplasm conservation. Since the commercial value of chilli pepper is based on pungency level, future studies are aimed at molecular marker based pungency phenotyping.Keywords: Capsicum annuum, Randomly Amplified Polymorphic DNA, Dendrogram, Polymerase Chain Reaction.African Journal of Biotechnology Vol. 12(30), pp. 4730-473

In vitro plantlet regeneration from nodal segments and shoot tips of Capsicum chinense Jacq. cv. Naga King Chili

An in vitro regeneration protocol was developed for Capsicum chinense Jacq. cv. Naga King Chili, a very pungent chili cultivar and an important horticultural crop of Nagaland (Northeast India). Maximum number of shoot (13 ± 0.70) was induced with bud-forming capacity (BFC) index of 10.8, by culturing nodal segments in Murashige and Skoog (MS) medium supplemented with 18.16 μM Thidiazuron (TDZ) followed by 35.52 μM 6-benzylaminopurine (BAP). Using shoot tips as explants, multiple shoot (10 ± 0.37) (BFC 8.3) was also induced in MS medium fortified with either 18.16 μM TDZ or 35.52 μM BAP. Elongated shoots were best rooted in MS medium containing 5.70 μM indole-3-acetic acid (IAA). Rooted plantlets thus developed were hardened in 2–3 weeks time in plastic cups containing potting mixture of a 1:1 mix of soil and cow dung manure and then subsequently transferred to earthen pots. The regenerated plants did not show any variation in the morphology and growth as compared to the parent plant

Electric-field control of magnetic domain wall motion and local magnetization reversal

Spintronic devices currently rely on magnetic switching or controlled motion of domain walls by an external magnetic field or spin-polarized current. Achieving the same degree of magnetic controllability using an electric field has potential advantages including enhanced functionality and low power consumption. Here, we report on an approach to electrically control local magnetic properties, including the writing and erasure of regular ferromagnetic domain patterns and the motion of magnetic domain walls, in multiferroic CoFe-BaTiO3 heterostructures. Our method is based on recurrent strain transfer from ferroelastic domains in ferroelectric media to continuous magnetostrictive films with negligible magnetocrystalline anisotropy. Optical polarization microscopy of both ferromagnetic and ferroelectric domain structures reveals that domain correlations and strong inter-ferroic domain wall pinning persist in an applied electric field. This leads to an unprecedented electric controllability over the ferromagnetic microstructure, an accomplishment that produces giant magnetoelectric coupling effects and opens the way to multiferroic spintronic devices.Comment: 6 pages, 4 figure

Harmful and beneficial aspects of Parthenium hysterophorus: an update

Parthenium hysterophorus is a noxious weed in America, Asia, Africa and Australia. This weed is considered to be a cause of allergic respiratory problems, contact dermatitis, mutagenicity in human and livestock. Crop production is drastically reduced owing to its allelopathy. Also aggressive dominance of this weed threatens biodiversity. Eradication of P. hysterophorus by burning, chemical herbicides, eucalyptus oil and biological control by leaf-feeding beetle, stem-galling moth, stem-boring weevil and fungi have been carried out with variable degrees of success. Recently many innovative uses of this hitherto notorious plant have been discovered. Parthenium hysterophorus confers many health benefits, viz remedy for skin inflammation, rheumatic pain, diarrhoea, urinary tract infections, dysentery, malaria and neuralgia. Its prospect as nano-medicine is being carried out with some preliminary success so far. Removal of heavy metals and dye from the environment, eradication of aquatic weeds, use as substrate for commercial enzyme production, additives in cattle manure for biogas production, as biopesticide, as green manure and compost are to name a few of some other potentials. The active compounds responsible for hazardous properties have been summarized. The aim of this review article is to explore the problem P. hysterophorus poses as a weed, the effective control measures that can be implemented as well as to unravel the latent beneficial prospects of this weed

Ternary copper(II) complexes containing imidazole as a primary ligand & amino acids as secondary ligands

325-327The formation constants of ternary complexes CuLA and CuL2A (where L=imidazole and A=valine, phenylalanine, tryptophan, methionine, ethionine and histidine) are reported at 35.0°C and μ = 0.2 M (KNO3). Stacking and hydrophobic interactions in these and analogous ternary complexes, are found to increase in the order: Cu-[imidazole]2A < Cu-[bis(imidazol-2-yl)methane] A < Cu-[Bipyridyl]A. The biological relevance of these model ternary complexes is discussed

Anomalous variation of magnetoresistance in Nd0.67−yEuySr0.33Mn03Nd_{0.67-y}Eu_ySr_{0.33}Mn_{03} manganites

A systematic investigation of Eu-doped Nd-based colossal magnetoresistive manganites with compositional formula $Nd_{0.67-y}Eu_ySr_{0.33}Mn_{03}$ (y = 0–0.67) has been undertaken to understand their structural, magnetic as well as electrical behavior. These materials were prepared by the citrate gel route, and were later characterized by X-ray diffraction (XRD), AC susceptibility, electrical resistivity etc; measurements. A detailed structural characterization of the XRD data has also been undertaken, using Rietveld refinement method. From a systematic analysis of electrical resistivity versus temperature data, it has been found that the last two samples of the series (y = 0.57 and 0.67) are found to exhibit charge order (CO) phenomenona, and that the CO state melts completely in the case of former sample (y = 0.57) while it melts partially only in the case of later one (y = 0.67), even in a magnetic field of 7 T. The observed behavior has been explained qualitatively. Some of the samples of the series are found to exhibit unusually large magnetoresistance over a wide temperature range in the low temperature region, and their behavior has been explained on the basis of phase segregation and an inter-grain spin polarized tunneling effect

Influence of A-site cation mismatch on structural, magnetic and electrical properties of lanthanum manganites

With a view to understand the influence of cation mismatch on magnetic as well as electrical behavior of colossal magnetoresistive materials, a systematic investigation of $La_{0.67}D_{0.33}MnO_3$ (D = Ca, Sr, Pb and Ba) manganite perovskites has been undertaken. The materials were prepared by sol–gel route sintering at $900^oC$ and after usual structural characterization by X-ray diffraction (XRD), their metal–insulator transition $(T_P)$ as well as magnetic transition $(T_C)$ temperatures were determined. The XRD data have been analyzed by Rietveld refinement technique. It has been concluded that apart from A-site cation, the size variance factor $(\sigma^2)$ also influences $T_P$ and $T_C$ values. The extrinsic nature of magnetoresistance in ferromagnetic metallic region is explained on the basis of inter-grain spin polarized tunneling effect. A systematic analysis of electrical resistivity data were carried out using theoretical models to understand the conduction mechanism. It has been concluded that the electrical resistivity data in the ferromagnetic (metallic) regime $(T < T_P)$ may be explained by domain or grain boundary and single magnon scattering processes, while the adiabatic small polaron and variable range hopping models may be used to explain the resistivity data of high temperature paramagnetic insulating region $(T > T_P)$

Electrical conduction mechanism for the investigation of charge ordering in Pr0.5Ca0.5MnO3 manganite system

In the present work, a systematic investigation of electrical transport mechanism has been used as a tool to investigate the charge-order suppression and its crossover in Pr0.5Ca0.5MnO3 (PCMO) manganite system with varying particle size and applied magnetic field. The samples with different particle sizes were synthesized by adopting sol-gel method and sintering at different temperatures. The prepared samples were thoroughly characterized by various physicochemical techniques. The activation energy and density of states at Fermi level obtained from the temperature-dependent electrical resistivity data clearly show the charge order crossover signatures and its suppression in the samples below 70 nm particle size and applied magnetic fields above 4 T. The significant change in various electrical transport parameters with the particle size around 70 nm could be attributed to the melting of long-range charge ordering behavior due to surface spin disorder and induced lattice-strain effects in PCMO manganite system

Equilibrium studies on ternary Cu(U) complexes containing tripolyphosphate, pyrophophate or adenosine-5' -triphosphate and a series of secondary ligands

407-411Ternary metal complexes of the type MLA where M = Cu(II); L= tripolyphosphate (TPP), pyrophosphate (PP) or adenosine-5'-triphosphate (ATP) and A= alanine, serine, methionine, phenylalanine, tryptophan, histidine, aspartic acid, ethylenediamine, 2,2'-bipyridyl, 1,10-phenanthroline, malonic acid and pyrocatechol have been investigated potentiometrically at 35°C and I=0.2 mol dm-3 (KNO3). The stabilities of the ternary metal complexes have been quantitatively compared with the stabilities of the corresponding binary metal complexes(MA) determined under identical experimental conditions Ternary complexes containing PP or ATP are found to be more stable than the corresponding complexes containing TPP. Various factors leading to differences in the relative stabilities of the ternary complexes are discussed