Phosphorylation and dephosphorylation of human myristoyltransferase type 1

N-Myristoyltransferase (NMT) is an essential eukaryotic enzyme that catalyzes the co-translational and (or) post-translational transfer of myristate to the amino terminal glycine residue of a number of important proteins, especially the non-receptor tyrosine kinases whose activity is important for tumorigenesis. Human NMT was found to be phosphorylated by non-receptor tyrosine kinase family members of Lyn, Fyn, and Lck and dephosphorylated by the Ca2+/calmodulin-dependent protein phosphatase, calcineurin. In this review, we discuss the cross-talk that exists between NMT and their N-myristoylated protein substrates. The cross-talk among NMT, tyrosine kinases, and phosphatases may be determined by their subcellular localization and by the physiological state of the cell.     

Nano RNA aptamer wire for analysis of vitamin B₁₂

A simple and stable RNA aptamer-based colorimetric sensor for the detection of vitamin B₁₂ using gold nanoparticles (AuNPs) has been proposed. Vitamin B₁₂ belongs to the B vitamin group and prevents pernicious anemia, which is caused by vitamin B₁₂ deficiency. A highly stable RNA aptamer that binds to vitamin B₁₂ was employed by structural modification of 2′-hydroxyl group of ribose to 2′-flouro in all pyrimidines indicated in lowercase in 35-mer aptamer (5′ GGA Acc GGu GcG cAu AAc cAc cuc AGu GcG AGc AA 3′). Aggregation of AuNPs was specifically induced by desorption of the vitamin B₁₂ binding RNA aptamer from the surface of AuNPs as a result of the aptamer–target interaction, leading to the color change from red to purple. The level of detection of vitamin B₁₂ was 0.1 μg/ml by successful optimization of the amount of the aptamer, AuNPs, salts, and stability of the aptamer. Analysis of vitamin B₁₂ was carried out, and the observed recovery was 92 to 95.3% with a relative standard deviation in the range of 2.08 to 8.27%. The results obtained were compared with those of the ultraviolet–visible (UV–vis) spectrometry method. This colorimetric aptasensor is advantageous for on-site detection with the naked eye.     

Synthesis, crystal structure, and catalytic studies on dinuclear copper(II) mesocates

Imine based bis-bidentate ligands H₂-m-xysal, (L₁H₂); H₂-m-xysal-Cl, (L₂H₂); H₂-m-xysal-Br, (L₃H₂); H₂-m-xysal-OCH_3, (L₄H₂); H₂-m-xysal-(t-Bu)_2, (L₅H₂) were synthesized and characterized. These substituted 1,3-bis(hydroxylbenzyl)-diaminoxylene dianion ligands upon treating with copper(II) acetate in 2:2 equivalent of L:M ratio, resulted in a series of binuclear [Cu₂(m-xysal)₂] neutral complexes 1-5. The crystal structures determined for the complexes 1 and 2 indicate a dinuclear association. The CH?π interaction observed between the metal-chelate ring and the hydrogens associated with m-xylene spacer moiety being first in this series of complexes, is demonstrated to stabilize the helical conformation through intramolecular self assembly process. The position of the resonance on the EPR spectra and the absence of ΔMs = ±1 feature for the complexes 2, 3, and 5 obtained for room temperature solid state samples revealed that the metal centers though exist in the dinuclear unit, they are separated from each other and possess a non-interacting monomer-type metal-metal association. The Cu(II) centers in all these complexes possessing an intermediate geometry between tetrahedral and square planar, an appropriate catalytic study converting 4-nitrobenzaldehye to corresponding nitroaldol was carried out using complex 5.     

Peptide derived from anti-idiotypic single-chain antibody is a potent antifungal agent compared to its parent fungicide HM-1 killer toxin peptide

Based on anti-idiotypic network theory in light of the need for new antifungal drugs, we attempted to identify biologically active fragments from HM-1 yeast killer toxin and its anti-idiotypic antibody and to compare their potency as an antifungal agent. Thirteen overlapping peptides from HM-1 killer toxin and six peptides from its anti-idiotypic single-chain variable fragment (scFv) antibodies representing the complementarity determining regions were synthesized. The binding affinities of these peptides were investigated and measured by Dot blot and surface plasmon resonance analysis and finally their antifungal activities were investigated by inhibition of growth, colony forming unit assay. Peptide P6, containing the potential active site of HM-1 was highly capable of inhibiting the growth of Saccharomyces cerevisiae but was less effective on pathogenic fungi. However, peptide fragments derived from scFv antibody exerted remarkable inhibitory effect on the growth of pathogenic strains of Candida and Cryptococcus species in vitro. One scFv-derived decapeptide (SP6) was selected as the strongest killer peptide for its high binding affinity and antifungal abilities on both Candida and Cryptococcus species with IC₅₀ values from 2.33 × 10⁻⁷ M to 36.0 × 10⁻⁷ M. SP6 peptide activity was neutralized by laminarin, a β-1,3-glucan molecule, indicating this peptide derived from scFv anti-idiotypic antibody retains antifungal activity through interaction with cell wall β-glucan of their target fungal cells. Experimental evidence strongly suggested the possibility of development of anti-idiotypic scFv peptide-based antifungal agents which may lead to improve therapeutics for the management of varieties of fungal infections.     

Regulation of cell cycle transition and induction of apoptosis in HL-60 leukemia cells by lipoic acid: role in cancer prevention and therapy

 

The most common semiquantitative method of evaluation of pulmonary lesions using ¹⁸F-FDG PET is FDG standardized uptake value (SUV). An SUV cutoff of 2.5 or greater has been used to differentiate between benign and malignant nodules. The goal of our study was to investigate the correlation between the size of pulmonary nodules and the SUV for benign as well as for malignant nodules.

Methods

Retrospectively, 173 patients were selected from 420 referrals for evaluation of pulmonary lesions. All patients selected had a positive CT and PET scans and histopathology biopsy. A linear regression equation was fitted to a scatter plot of size and SUV_max for malignant and benign nodules together. A dot diagram was created to calculate the sensitivity, specificity, and accuracy using an SUV_max cutoff of 2.5.

Results

The linear regression equations and (R²)s as well as the trendlines for malignant and benign nodules demonstrated that the slope of the regression line is greater for malignant than for benign nodules. Twenty-eight nodules of group one (≤ 1.0 cm) are plotted in a dot diagram using an SUV_max cutoff of 2.5. The sensitivity, specificity, and accuracy were calculated to be 85%, 36% and 54% respectively. Similarly, sensitivity, specificity, and accuracy were calculated for an SUV_max cutoff of 2.5 and found to be 91%, 47%, and 79% respectively for group 2 (1.1–2.0 cm); 94%, 23%, and 76%, respectively for group 3 (2.1–3.0 cm); and 100%, 17%, and 82%,, respectively for group 4 (> 3.0 cm). The previous results of the dot diagram indicating that the sensitivity and the accuracy of the test using an SUV_max cutoff of 2.5 are increased with an increase in the diameter of pulmonary nodules.

Conclusion

The slope of the regression line is greater for malignant than for benign nodules. Although, the SUV_max cutoff of 2.5 is a useful tool in the evaluation of large pulmonary nodules (> 1.0 cm), it has no or minimal value in the evaluation of small pulmonary nodules (≤ 1.0 cm).     

Spore associated bacteria of arbuscular mycorrhizal fungi improve maize tolerance to salinity by reducing ethylene stress level

The role of spore associated bacteria of arbuscular mycorrhizal fungi (AMF) in improving plant growth and alleviating salt stress is a potential area to explore. In the present study, 22 bacteria isolated from the spore walls of AMF were identified to contain 1-aminocyclopropane-1-carboxylate deaminase. These were tested for their ability to improve seed germination and alleviate salt stress in the early growth of maize. Among the isolates, 19 bacteria that were able to grow at 4?% NaCl were used for germination assay. Two bacteria and seven bacteria significantly improved maize seed germination at 100 mM NaCl and 200 mM NaCl, respectively. Based on the presence of plant growth promoting (PGP) characters and the ability to improve seed germination, five strains were chosen for further experiments. At 0 mM NaCl, all the strains were able to increase maize shoot and root growth significantly. At 25 mM NaCl, except for Bacillus aryabhattai S210B15, all the strains were able to increase shoot and root growth significantly. At 50 mM NaCl, Bacillus aryabhattai S110B3 and B. aryabhattai S210B15 significantly improved shoot length, whereas, Pseudomonas koreensis S2CB35 and B. aryabhattai S210B15 significantly increased root length. Although salinity increased ethylene production in maize, bacterial inoculation significantly reduced the ethylene level at 0, 25 and 50 mM NaCl. Among the five strains, only P. koreensis S2CB35 showed the presence of PGP functional traits of nifH, acdS and nodA genes.     

Characterization of a cold-tolerant plant growth-promoting bacterium Pantoea dispersa 1A isolated from a sub-alpine soil in the North Western Indian Himalayas

Pantoea dispersa strain 1A is a Gram-negative rod-shaped, yellow-pigmented bacterium isolated on nutrient agar plates incubated at 4°C. The identity of the bacterium was confirmed by sequencing of the 16 S rRNA gene. It was capable of growing at temperatures ranging from 4 to 42°C, but maximum growth was observed at 30°C. It is endowed with multiple plant growth promotion attributes such as phosphate solubilization, IAA production, siderophore production and HCN production, which are expressed differentially at sub-optimal temperatures (15 and 4°C). It was able to solubilize phosphate (17.6 μg of P₂O₅ ml⁻¹ day⁻¹), and produce IAA (3.7 μg ml⁻¹ day⁻¹), at 15°C. Qualitative detection of siderophore production and HCN were also observed at 15°C. At 4°C it was found to express all the plant growth promotion attributes. This bacterial isolate was able to positively influence and promote the growth and nutrient uptake parameters of wheat (cv. VL.802) under glasshouse conditions. Hence in the context, of cold wheat-growing environments, it is proposed that Pantoea dispersa 1A (MTCC 8706), could be deployed as an inoculant to attain the desired results of bacterization.