Sharp intense line in the bioluminescence emission of the firefly

Numerous investigations have been carried out on the spectral distribution of the light of different species of fireflies. Here we record the emission spectrum of the Indian species of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera : Lampyridae : Luciolinae) on a color film. Green and red color-sectors, with an intense yellow one in between, appear in this spectrum. Intensity profile of this spectrum reveals a hitherto undetected strong narrow yellow line, which lies within the full-width-at-half maximum (FWHM) of the intensity profile. The spectrum recorded in a high-resolution spectrometer confirms the presence of this sharp intense line. This finding lends support to an earlier drawn analogy between the in vivo emission of the firefly and laser light.     

405 nm-Excited Fluorescence Spectra of the Juice of the Lemon (Citrus x Limon)

A 405 nm diode laser is used to excite fluorescence of juices of raw and ripe lemons. Emission bands appear approximately at 520 nm and 670 nm. Fluorescence intensity ratio F520/F670 is determined for the two stages. Variation in the fluorescence intensity ratio is observed during the process of ripening or growth of the fruit. Time-resolved spectra at this excitation wavelength reveal two decay times at both the stages at the emission wavelength of 520 nm, and two decay times at the raw stage and one decay time at the ripe stage at 670 nm.     

Virological Characteristics of Acute Hepatitis B in Eastern India: Critical Differences with Chronic Infection

Hepatitis B Virus (HBV) manifests high genetic variability and is classifiable into ten genotypes (A-J). HBV infection can lead to variable clinical outcomes, ranging from self-limiting acute hepatitis to active chronic hepatitis, cirrhosis and hepatocellular carcinoma. The present study characterizes HBV strains circulating among patients with acute (AHB) and chronic HBV infection (CHB). Among a total of 653 HBsAg positive cases, 40 manifested acute infection. After sequencing the surface(S), basal core promoter/pre-core(BCP/PC) and the X gene regions, phylogenetic tree was constructed using MEGA4 by neighbor-joining method. Statistical robustness was established with bootstrap analysis. Nucleotide diversity was determined by Shannon entropy per site using the Entropy program of the Los Alamos National Laboratories. Analyses of acute patients revealed that HBV/D2 is the major circulating sub-genotype and commonly associated with sexual promiscuity and the age group between15-30 years. Comparison of AHB and CHB patients revealed that HBeAg positivity, ALT levels and genotype D were significantly high in AHB, whereas CHB patients were predominantly male, had a high viral load, and were commonly associated with genotype C. The frequencies of mutations in the S, BCP/PC, and X gene were low in AHB as compared to CHB. Drug resistant mutations were not detectable in the polymerase gene of AHB. Average nucleotide diversity in AHB was considerably low as compared to CHB. Further, the highest average ΔH (average difference in entropy between chronic and acute infection) was observed in the BCP/PC region implying that this region was most vulnerable to mutations upon HBV persistence, especially in case of genotype C. Additionally, among all substitutions, the A1762T and G1764A BCP mutations were the strongest indicators of chronicity. In conclusion, the study exhibits a general portrait of HBV strains circulating among acute hepatitis B patients in Eastern India and their intricate differences with chronic patients which should be useful from the clinical point of view.     

Comparison of proteins expressed on secretory vesicle membranes and plasma membranes of human neutrophils

Secretory vesicles are neutrophil intracellular storage granules formed by endocytosis. Understanding the functional consequences of secretory vesicle exocytosis requires knowledge of their membrane proteins. The current study was designed to use proteomic technologies to develop a more complete catalog of secretory vesicle membrane proteins and to compare the proteomes of secretory vesicle and plasma membranes. A total of 1118 proteins were identified, 573 (51%) were present only in plasma membrane-enriched fractions, 418 (37%) only in secretory vesicle-enriched membrane fractions, and 127 (11%) in both fractions. Gene Ontology categorized 373 of these proteins as integral membrane proteins. Proteins typically associated with other intracellular organelles, including nuclei, mitochondria, and ribosomes, were identified in both membrane fractions. Ingenuity Pathway Knowledge Base analysis determined that the majority of canonical and functional pathways were significantly associated with proteins from both plasma membrane-enriched and secretory vesicle-enriched fractions. There were, however, some canonical signaling pathways that involved proteins only from plasma membranes or secretory vesicles. In conclusion, a number of proteins were identified that may elucidate mechanisms and functional consequences of secretory vesicle exocytosis. The small number of common proteins suggests that the hypothesis that secretory vesicles are formed from plasma membranes by endocytosis requires more critical evaluation.     

Bioluminescence emissions of the firefly <Emphasis Type="Italic">Luciola praeusta</Emphasis> Kiesenwetter 1874 (Coleoptera: Lampyridae: Luciolinae)

We recorded the in vivo emission and time-resolved spectra of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera: Lampyridae: Luciolinae). The emission spectrum shows that the full width at half maximum (FWHM) value for this particular species is 55 nm, which is significantly narrower than the in vivo half-widths reported till now. The time-resolved spectrum reveals that a flash of about 100 ms duration is, in fact, composed of a number of microsecond pulses. This suggests that the speed of the enzyme-catalysed chemiluminescence reaction in the firefly for the emission of light is much faster than was previously believed. A version of this article has already appeared in an archive Nature Precedings; see     

Regiospecific one-pot synthesis of pyrimido[4,5-d]pyrimidine derivatives in the solid state under microwave irradiations

Electron rich 6-[(dimethylamino)methylene]amino uracil 1, undergoes [4+2] cycloaddition reactions with various in situ generated glyoxylate imine and imine oxides 6 to provide novel pyrimido[4,5-d]pyrimidine derivatives of biological significance, after elimination of dimethylamine from the (1:1) cycloadducts and oxidative aromatisation. This procedure provides a convenient method for the direct synthesis of pyrimido[4,5-d]pyrimidines in excellent yields when carried out in the solid state and under microwave irradiations.