Numerical Simulation of Electromagnetic Wave Interaction with Spheroidal Core-Shell Nanoparticle: Dependence of Surface Plasmon Resonance on Core-Shell Composition

Plasmonics - In the present work, we report our observations drawn from the numerical simulation of absorption and scattering efficiencies of spheroid shape nanostructures using discrete dipole...     

Pseudomonas aeruginosa: A risk factor for fertility in male mice

The present study was designed to evaluate the effect of P. aeruginosa on reproductive potential of male mice via a series of in vitro and in vivo experiments. In vitro studies involved sperm parameters, Mg²⁺ATPase activity and acrosome status. In vivo study employed male mice which in the right vas deferens received 20?μl of either PBS (Group I) or 10⁴ cfu of P. aeruginosa (Group II). The animals were sacrificed on day 3, 7 and 14 and various parameters viz. body weight, TSI (%), bacterial load, spermiogram {i.e. sperm count, motility (%), viability (%) and morphology}, lipid peroxidation and tissue histopathology were evaluated. The results revealed that cell free supernatant of P. aeruginosa resulted in reduced motility, viability, Mg²⁺dependent ATPase activity and premature acrosomal loss of mouse spermatozoa in vitro. In vivo study showed that in comparison to group I, group II revealed significant alterations in all the parameters on all the days of sacrifice. Further, when reproductive organs of right and left side of mice in group II were compared, the right side demonstrated more devastating effects in terms of altered TSI (%) of testis and cauda epididymis, higher bacterial counts, azoospermia, increased malondialdehyde levels and severe inflammation in tissue histopathology in comparison to left side where bacteria disseminated in reduced numbers, thereby, resulting in insignificant changes in TSI (%), spermiogram, malondialdehyde levels and tissue histology. This study demonstrates that the colonization of P. aeruginosa in male genital tract could be a risk factor for fertility.     

Composition and functional property of photosynthetic pigments under circadian rhythm in the cyanobacterium <Emphasis Type="Italic">Spirulina platensis</Emphasis>

Circadian rhythm is an important endogenous biological signal for sustainable growth and development of cyanobacteria in natural ecosystems. Circadian effects of photosynthetically active radiation (PAR), ultraviolet-A (UV-A) and ultraviolet-B (UV-B) radiations on pigment composition have been studied in the cyanobacterium Spirulina platensis under light (L)/dark (D) oscillation with a combination of 4/20, 8/16, 12/12, 16/8, 20/4 and 24/24 h time duration. Circadian exposure of PAR?+?UV-A (PA) and PAR?+?UV-A?+?UV-B (PAB) showed more than twofold decline in Chl a, total protein and phycocyanin (PC) in light phase and significant recovery was achieved in dark phase. The fluorescence emission wavelength of PC was shifted towards lower wavelengths in the light phase of PAB in comparison to P and PA whereas the same wavelength was retrieved in the dark phase. The production of free radicals was accelerated twofold in the light phase (24 h L) whereas the same was retrieved to the level of control during the dark phase. Oxidatively induced damage was alleviated by antioxidative enzymes such as catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and ascorbate peroxidase (APX) in the light phase (0–24-h L) whereas the dark phase showed significant inhibition of the same enzymes. Similar characteristic inhibition of free radicals and recovery of PC was observed inside cellular filament after circadian rhythm of 24/24 h (L/D). Circadian exposure of P, PA and PAB significantly altered the synthesis and recovery of pigments that could be crucial for optimization and sustainable production of photosynthetic products for human welfare.     

Construction and characterization of mutated LEA peptides in Escherichia coli to develop an efficient protein expression system

To develop an efficient protein expression system, we designed a late embryogenesis abundant (LEA) peptide by mutating the LEA peptide constructed in our previous study (LEA‐I). The peptide is based on the repeating units of an 11mer motif characteristic of LEA proteins from Polypedilum vanderplanki larvae. In the amino acid sequence of the 13mer LEA peptide, glycine at the 6th and 12th positions was replaced with other amino acids via point mutations. Glutamic acid, lysine, leucine, and asparagine in the LEA peptide at the 6th and 12th positions increased green fluorescence protein (GFP) expression. The GFP expression of the mutated LEA peptide was 1.5 to 2.0 times higher than that without LEA peptide. In contrast, the serine‐containing mutated LEA peptide has low GFP expression levels. We hypothesize that the position of amino acids and the nature of amino acid in LEA peptide are important for our coexpression system. These data suggest that the size, structure, and charge of amino acids in the LEA peptide improve the protection and expression of the target protein. The amino acid balance also plays an important role in the expression of the target protein.