Characterisation of carboxymethyl cellulose and polyacrylamide graft copolymer

The synthesis of carboxymethyl cellulose-g-polyacrylamide was carried out by a ceric ion induced solution polymerization technique. By varying the amount of catalyst and monomer, six different grades of graft copolymers were synthesized. These graft copolymers were characterized by elemental analysis, infrared spectroscopy, rheological studies, scanning electron microscopy, thermal analysis, viscosity measurement and X-ray diffractometry. They exhibit distinguished flocculation characteristics in various suspensions and effluents. Their flocculation and viscosifying characteristics are drastically enhanced on their hydrolysis.     

Simple sequence repeats in organellar genomes of rice: frequency and distribution in genic and intergenic regions

MOTIVATION: Simple sequence repeats (SSRs) are abundant across genomes. However, the significance of SSRs in organellar genomes of rice has not been completely understood. The availability of organellar genome sequences allows us to understand the organization of SSRs in their genic and intergenic regions. RESULTS: We have analyzed SSRs in mitochondrial and chloroplast genomes of rice. We identified 2528 SSRs in the mitochondrial genome and average 870 SSRs in the chloroplast genomes. About 8.7% of the mitochondrial and 27.5% of the chloroplast SSRs were observed in the genic region. Dinucleotides were the most abundant repeats in genic and intergenic regions of the mitochondrial genome while mononucleotides were predominant in the chloroplast genomes. The rps and nad gene clusters of mitochondria had the maximum repeats, while the rpo and ndh gene clusters of chloroplast had the maximum repeats. We identified SSRs in both organellar genomes and validated in different cultivars and species.     

Tumor cell imaging using the intrinsic emission from PAMAM dendrimer: a case study with HeLa cells

HeLa 229 cells were treated with methotrexate (MTX) and doxorubicin (DOX), utilizing fourth generation (G4), amine terminated poly(amidoamine) {PAMAM} dendrimer as the drug carrier. In vitro kinetic studies of the release of both MTX and DOX in presence and absence of G4, amine terminated PAMAM dendrimers suggest that controlled drug release can be achieved in presence of the dendrimers. The cytotoxicity studies indicated improved cell death by dendrimer-drug combination, compared to the control experiments with dendrimer or drug alone at identical experimental conditions. Furthermore, HeLa 229 cells were imaged for the first time utilizing the intrinsic emission from the PAMAM dendrimers and drugs, without incorporating any conventional fluorophores. Experimental results collectively suggest that the decreased rate of drug efflux in presence of relatively large sized PAMAM dendrimers generates high local concentration of the dendrimer-drug combination inside the cell, which renders an easy way to image cell lines utilizing the intrinsic emission properties of PAMAM dendrimer and encapsulated drug molecule.     

Regenerated silica-based RNA purification columns to address the short supply of RNA purification kits for COVID-19 diagnosis

Molecular Biology Reports - RT-qPCR technique is the current world-wide method used for the early detection of SARS-CoV2 RNA in the suspected clinical samples. Viral RNA extraction is the key...     

Ageing of chloroplasts in vitro I. Quantitative analysis of the degradation of pigments, proteins and nucleic acids

Patterns of the degradation of various photosynthetic pigments,proteins and nucleic acids have been studied during the ageingof isolated chloroplasts in the light and dark. Ageing causesdegradation of chlorophylls and carotenoids, but the rate ofdegradation of both pigments was faster during light than duringdark ageing. Carotenoids are degraded much faster than chlorophyllsboth in the light and dark. The relatively greater degradationof carotenoids than chlorophylls in the dark suggests the involvementof some mechanism other than the photodestruction of carotenoidsduring ageing. The rate of decline for the DNA content is appreciablyslower than that of RNA and chloroplast-protein, but the degradationof latter two macromolecules is less than that of the chlorophyllsand carotenoids. (Received October 30, 1978; )     

The Mystery of Oxygen Evolution: Analysis of Structure and Function of Photosystem II,the Water-Plastoquinone Oxido-Reductase

Photosystem II (PS II) of thylakoid membrane of photosynthetic organisms has drawn attention of researchers over the years because it is the only system on Earth that provides us with oxygen that we breathe. In the recent past, structure of PS II has been the focus of research in plant science. The report of X-ray crystallographic structure of PS II complex by the research groups of James Barber and So Iwata in UK (K.N. Ferreira et al. Science 303: 1831–38, 2004) is a milestone in the area of research in photosynthesis. It follows the pioneering and elegant work from the laboratories of Horst Witt and W. Saenger in Germany (A. Zouni et al. Nature 409: 739–743, 2001), and J. Shen in Japan (N. Kamiya and J. Shen, Proc Natl Acad Sci USA 100: 98–103, 2003). It is time to analyze the historic events during the long journey made by the researchers to arrive at this point. This review makes an attempt to critically review the growth of the advancement of concepts and knowledge on the photosystem in the background of technological development. We conclude the review with perspectives on research and technology that should reveal the complete story of PS II of thylakoid in the future.     

Global expression profiles from C57BL/6J and DBA/2J mouse lungs to determine aging-related genes.

This study identified gene expression profiles that provided evidence for genomic mechanisms underlying the pathophysiology of aging lung. Aging lungs from C57BL/6 (B6) and DBA/2 (D2) mouse strains differ in physiology and morphometry. Lungs were harvested from B6 mice at 2, 18, and 26 mo and from D2 mice at 2 and 18 mo of age. Purified RNA was subjected to oligonucleotide microarray analyses, and differential expression analyses were performed for comparison of various data sets. A significant majority of differentially expressed genes were upregulated with aging in both strains. Aging D2 lungs uniquely exhibited upregulation in stress-response genes including xenobiotic detoxification cascades. In contrast, aging B6 lungs showed downregulation of heat shock-response genes. Age-dependent downregulation of genes common to both B6 and D2 strains included several collagen genes (e.g., Col1a1 and Col3a1). There was a greater elastin gene (Eln) expression in D2 mice at 2 mo, and Eln was uniquely downregulated with age in this strain. The matrix metalloproteinase 14 gene (Mmp14), critical to alveolar structural integrity, was also downregulated with aging in D2 mice only. Several polymorphisms in the regulatory and untranslated regions of Mmp14 were identified between strains, suggesting that variation in Mmp14 gene regulation contributes to accelerated aging of lungs in D2 mice. In summary, lungs of B6 and D2 mice age with variable rates at the gene expression level, and these quantifiable genomic differences provide a template for understanding the variability in age-dependent changes in lung structure and function.     

An efficient method for medium throughput screening of cuticular wax composition in different plant species

Introduction

Most aerial plant organs are covered by a cuticle, which largely consists of cutin and wax. Cuticular waxes are mixtures of dozens of compounds, mostly very-long-chain aliphatics that are easily extracted by solvents. Over the last four decades, diverse cuticular wax analysis protocols have been developed, most of which are complex and time-consuming, and need to be adapted for each plant species or organ. Plant genomics and breeding programs often require mid-throughput metabolic phenotyping approaches to screen large numbers of individuals and obtain relevant biological information.

Objectives

To generate a fast, simple and user-friendly methodology able to capture most wax complexity independently of the plant, cultivar and organ.

Methods

Here we present a simple GC–MS method for screening relatively small wax amounts, sampled by short extraction with a versatile, uniform solvent. The method will be tested and validated in leaves and fruits from three different crop species: tomato (Solanum lycopersicum), apple (Malus domestica) and hybrid aspen (Populus tremula × tremuloides).

Results

Consistent results were obtained in tomato cultivar M82 across three consecutive years (2010–2012), two organs (leaf and fruit), and also in two different tomato (M82 and MicroTom) and apple (Golden Delicious and Granny Smith) cultivars. Our results on tomato wax composition match those reported previously, while our apple and hybrid aspen analyses provide the first comprehensive cuticular wax profile of these species.

Conclusion

This protocol allows standardized identification and quantification of most cuticular wax components in a range of species.

     

Mechanical insights of oxythiamine compound as potent inhibitor for human transketolase-like protein 1 (TKTL1 protein)

Transketolase is a connecting link between glycolytic and pentose phosphate pathway, which is considered as the rate-limiting step due to synthesis of large number of ATP molecule and it can be proposed as a plausible target facilitating the growth of cancerous cells suggesting its potential role in cancer. Oxythiamine, an antimetabolite has been proved to be an efficient anticancerous compound in vitro, but its structural elucidation of the inhibitory mechanism has not yet been done against the human transketolase-like 1 protein (TKTL1). The three-dimensional (3D) structure of TKTL1 protein was modeled and subjected for refinement, stability and validation. Based on the reported homologs of transketolase (TKT), the active site residues His46, Ser49, Ser52, Ser53, Ile56, Leu82, Lys84, Leu123, Ser125, Glu128, Asp154, His160, Thr216 and Lys218 were identified and considered for molecular-modeling studies. Docking studies reveal the H-bond interactions with residues Ser49 and Lys218 that could play a major role in the activity of TKTL1. Molecular dynamics (MD) simulation study was performed to reveal the comparative stability of both native and complex forms of TKTL1. MD trajectory at 30?ns, confirm the role of active site residues Ser49, Lys84, Glu128, His160 and Lys218 in suppressing the activity of TKTL1. Glu128 is observed to be the most important residue for deprotonation state of the aminopyrimidine moiety and preferred to be the site of inhibitory action. Thus, the proposed mechanism of inhibition through in silico studies would pave the way for structure-oriented drug designing against cancer.     

Formulation of Sustained-Release Dosage Form of Verapamil Hydrochloride by Solid Dispersion Technique Using Eudragit RLPO or Kollidon®SR

The release of verapamil hydrochloride from tablets with Eudragit RLPO or Kollidon®SR with different drug-to-polymer ratios were investigated with a view to develop twice-daily sustained-release dosage form by solid dispersion (SD) technique. The SDs containing Eudragit RLPO or Kollidon®SR at drug-polymer ratios of 1:1, 1:2, and 1:3 with verapamil hydrochloride were developed using solvent evaporation technique. The physical mixtures of drug and both polymers were prepared by using simple mixing technique at the same ratio as solid dispersion. The physicochemical properties of solid dispersion were evaluated by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The study of DSC, XRD, and FTIR could not show significant interaction between verapamil HCl and Kollidon®SR or Eudragit RLPO. The solid dispersions or physical mixtures were compressed to tablets. The tablets were prepared with solid dispersions containing Eudragit RLPO or Kollidon®SR, with all the official requirements of tablet dosage forms fulfilled. Tablets prepared were evaluated for the release of verapamil hydrochloride over a period of 12 h in pH 6.8 phosphate buffer using US Pharmacopoeia type II dissolution apparatus. The in vitro drug release study revealed that the tablet containing Eudragit has extended the release rate for 12 h whereas the tablet containing Kollidon®SR at the same concentration has extended the release rate up to 8 h. The in vitro release profile and the mathematical models indicate that release of verapamil hydrochloride can be effectively controlled from a tablet containing solid dispersions of Eudragit RLPO. The reduction of size fraction of the SD system from 200–250 to 75–125 μm had a great effect on the drug release.