Characterization of human lysophospholipid acyltransferase 3

Esterifying lysophospholipids may serve a variety of functions, including phospholipid remodeling and limiting the abundance of bioactive lipids. Recently, a yeast enzyme, Lpt1p, that esterifies an array of lysophospholipids was identified. Described here is the characterization of a human homolog of LPT1 that we have called lysophosphatidylcholine acyltransferase 3 (LPCAT3). Expression of LPCAT3 in Sf9 insect cells conferred robust esterification of lysophosphatidylcholine in vitro. Kinetic analysis found apparent cooperativity with a saturated acyl-CoA having the lowest K_0.5 (5 μM), a monounsaturated acyl-CoA having the highest apparent V_max (759 nmol/min/mg), and two polyunsaturated acyl-CoAs showing intermediate values. Lysophosphatidylethanolamine and lysophosphatidylserine were also utilized as substrates. Electrospray ionization mass spectrometric analysis of phospholipids in Sf9 cells expressing LPCAT3 showed a relative increase in phosphatidylcholine containing saturated acyl chains and a decrease in phosphatidylcholine containing unsaturated acyl chains. Targeted reduction of LPCAT3 expression in HEK293 cells had essentially an opposite effect, resulting in decreased abundance of saturated phospholipid species and more unsaturated species. Reduced LPCAT3 expression resulted in more apoptosis and distinctly fewer lamellipodia, suggesting a necessary role for lysophospholipid esterification in maintaining cellular function and structure.     

Age-associated changes in erythrocyte glutathione peroxidase activity: correlation with total antioxidant potential

Oxidative stress is believed to play a central role in aging and age-associated diseases. It leads to oxidative changes in human red blood cells (RBCs) in vivo and in vitro. In this study, we evaluated the oxidative damage to the erythrocytes during aging in the humans using RBC as a model, by measuring the cytosolic antioxidant enzyme glutathione peroxidase (GPx) activity. GPx activity was found to be significantly decreased as a function of human age and positively correlated with total antioxidant capacity, while negatively correlated with SOD activity. Thus, results of the present study showed involvement of oxidative stress as one of the risk factors, which can initiate and/or promote human aging.     

Non-stop mRNA decay initiates at the ribosome

The translation machinery deciphers genetic information encoded within mRNAs to synthesize proteins needed for various cellular functions. Defective mRNAs that lack in-frame stop codons trigger non-productive stalling of ribosomes. We investigated how cells deal with such defective mRNAs, and present evidence to demonstrate that RNase R, a processive 3'-to-5' exoribonuclease, is recruited to stalled ribosomes for the specific task of degrading defective mRNAs. The recruitment process is selective for non-stop mRNAs and is dependent on the activities of SmpB protein and tmRNA. Most intriguingly, our analysis reveals that a unique structural feature of RNase R, the C-terminal lysine-rich (K-rich) domain, is required both for productive ribosome engagement and targeted non-stop mRNA decay activities of the enzyme. These findings provide new insights into how a general RNase is recruited to the translation machinery and highlight a novel role for the ribosome as a platform for initiating non-stop mRNA decay.     

Fruit-specific Over-expression of LeEXP1 Gene in Tomato Alters Fruit Texture

Expansins are cellular proteins with diverse physiological functions. Expression of fruit-specific expansin gene in tomato is associated with fruit softening — a desirable trait from the processing point of view. In the present study, an expansin gene LeEXP1 was introduced via Agrobacterium tumefaciens in sense orientation under the control of a fruit-specific promoter LeACS4 with nptII gene as selection marker in Indian tomato cv Pusa Uphar. PCR detection and Southern blot analysis confirmed the integration of the transgene in the transformed tomato plants. RT-PCR and northern blot analysis using total RNA isolated from leaves and fruits confirmed over-expression of the LeEXP1 gene in transgenic fruits as compared to the wild type plants. Apart from the visual change in increased red colouration of fruits at different stages of ripening, overexpression of the LeEXP1 gene resulted in enhanced fruit softening, as determined by force required to rupture the fruit pericarp, in the transgenic fruits from breaker stage onwards as compared to the non-transformed wild type fruits. The results thus suggest an improvement in texture of the LeEXP1 over-expressing fruits, which might be useful for tomato processing industry.     

Larvicidal efficacy of Aloe barbadensis and Cannabis sativa against the malaria vector Anopheles stephensi (Diptera: Culicidae)

Anopheles stephensi is the primary vector of malaria, an endemic disease in India. An effort to control An. stephensi larvae by leaf extracts of Aloe barbadensis (Liliaceae) and Cannabis sativa (Moraceae) was made under laboratory conditions. A carbon tetrachloride extract of A. barbadensis was the most effective of all the extracts tested for larvicidal activity against the anopheline larvae, with LC₅₀ 15.58 and 8.04 p.p.m. after 24 and 48 h of exposure, respectively. Thus, the leaf extract of A. barbadensis has active components that could be useful as a larvicide of ecocongenial nature against malaria vectors.     

Information theoretic perspective on genome clustering

Shannon’s information theoretic perspective of communication helps one to understand the storage and processing of information in one-dimensional sequences. An information theoretic analysis of 937 available completely sequenced prokaryotic genomes and 238 eukaryotic chromosomes is presented. Information content (Id) values were used to cluster these chromosomes. Chargaff’s second parity rule i.e compositional self-complementarity, an empirical fact is observed in all the genomes, except for the proteobacteria Candidatus Hodgkinia cicadicola. High information content, arising out of biased base composition in all the 14 chromosomes of Plasmodium falciparum is found among two other genomes of prokaryotes viz. Buchnera aphidicola str. Cc (Cinara cedri) and Candidatus Carsonella ruddii PV. Despite size and compositional variations, both prokaryotic and eukaryotic genomes do not deviate significantly from an equiprobable and random situation. Eukaryotic chromosomes of an organism tend to have similar informational restraints as seen when a simple distance based method is used to cluster them. In eukaryotes, in certain cases, Id values are also similar for the two arms (p and q arm) of the chromosomes. The results of this current study confirm that the information content can provide insights into the clustering of genomes and the evolution of messaging strategies of the genomes. An efficient and robust Perl CGI standalone tool is created based on this information theory algorithm for the analysis of the whole genomes and is made available at https://github.com/AlagurajVeluchamy/InformationTheory.     

Niosomal Gel of Lornoxicam for Topical Delivery: In vitro Assessment and Pharmacodynamic Activity

Lornoxicam is a potent oxicam class of non steroidal anti-inflammatory agent, prescribed for mild to moderate pain and inflammation. Niosomal gel of lornoxicam was developed for topical application. Lornoxicam niosomes (Lor-Nio) were fabricated by thin film hydration technique. Bilayer composition of niosomal vesicles was optimized. Lor-Nio dispersion was characterized by DSC, XRD, and FT-IR. Morphological evaluation was performed by scanning electron microscopy (SEM). Lor-Nio dispersion was incorporated into a gel using 2% w/w Carbopol 980 NF. Rheological and texture properties of Lor-Nio gel formulation showed suitability of the gel for topical application. The developed formulation was evaluated for in vitro skin permeation and skin deposition studies, occlusivity test and skin irritation studies. Pharmacodynamic activity of the Lor-Nio gel was performed by carragenan-induced rat paw model. Optimized Lor-Nio comprised of Span 60 and cholesterol in a molar ratio of 3:1 with 30 μM dicetyl palmitate as a stabilizer. It had particle size of 1.125 ± 0.212 μm (d₉₀), with entrapment efficiency of 52.38 ± 2.1%. DSC, XRD, and IR studies showed inclusion of Lor into niosomal vesicles. SEM studies showed spherical closed vesicular structure with particles in nanometer range. The in vitro skin permeation studies showed significant improvement in skin permeation and skin deposition for Lor-Nio gel (31.41 ± 2.24 μg/cm², 30.079 ± 1.2 μg/cm²) over plain lornoxicam gel (7.37 ± 1.27 μg/cm², 6.6 ± 2.52 μg/cm²). The Lor-Nio gel formulation showed enhanced anti-inflammatory activity by exhibiting mean edema inhibition (87.69 ± 1.43%) which was significantly more than the plain lornoxicam gel (53.84 ± 2.21%).KEY WORDS: anti-inflammatory activity, lornoxicam, niosomes, rheology, texture analysis     

Rock phosphate solubilization by psychrotolerant Pseudomonas spp. and their effect on lentil growth and nutrient uptake under polyhouse conditions

Psychrotolerant Pseudomonas isolates (RT5RP2 and RT6RP) isolated from the rhizoplane of wild grass at 3,100 and 3,800 m above mean sea level, respectively, from Rudraprayag district of Uttarakhand (India), were found to solubilize Udaipur rock phosphate (URP). Both isolates grew at temperatures ranging from 4 to 30 °C. Kinetics of phosphate solubilization by the bacterial strains showed a nonlinear regression of the rate of P solubilization, which fitted best in the power model, and showed a declining trend across three different temperatures. Under pot culture conditions, bacterization of lentil seeds (cv. VL Masoor 507) with the psychrotolerant Pseudomonas strains when combined with URP as a sole source of phosphorus resulting in significant enhancement in P uptake of the plants, compared to the application of rock phosphate alone.