Position-specific incorporation of a highly photodurable and blue-laser excitable fluorescent amino acid into proteins for fluorescence sensing

A new fluorescent amino acid, L-2-acridonylalanine, was incorporated into proteins at specific positions using 4-base codon/anticodon strategy. The efficiency of the incorporation was high enough to obtain enough quantities of the mutants. The acridonyl group was highly fluorescent when it was excited at the wavelengths of blue-lasers and was highly photodurable compared with conventional fluorophores often used for biological analyses. The fluorescence intensity was sensitive to small changes in the polarity of the environment. When the nonnatural amino acid was incorporated into specific positions of streptavidin, the mutant protein worked as a fluorescent sensor to biotin. Similarly, when the amino acid was incorporated into camel single-chain antibody, the mutant protein sensitively responded to the antigen molecule. The high incorporation efficiency, the high photodurability, the excitability with blue-lasers, and high sensitivity to the environment make the acridonylalanine as the promising fluorescent amino acid for sensing small molecules when incorporated into specific positions of various antibodies, receptors, and enzymes.     

Human projected area factors for detailed direct and diffuse solar radiation analysis

Projected area factors for individual segments of the standing and sedentary human body were modelled for both direct and diffuse solar radiation using detailed 3D geometry and radiation models. The local projected area factors with respect to direct short-wave radiation are a function of the solar azimuth angle () between 0°<<360° and the solar altitude () angles between –90°<<+90°. In case of diffuse solar radiation from the isotropic sky the local human projected area factors were modelled as a function of the ground albedo () ranging between 0<<1. The model was validated against available experimental data and showed good general agreement with projected area factors measured for both the human body as a whole and for local quantities. Scientists can use the equations to predict the inhomogeneous irradiation and absorption of direct and diffuse solar radiation and UV-radiation at surfaces of the human body. In conjunction with detailed multi-node models of human thermoregulation the equations can be used to predict the physiological implications of solar radiation and outdoor weather conditions on humans.     

The prevalence of Toxoplasma gondii antibodies in wild and captive cetaceans from Japan

The seroprevalence of Toxoplasma gondii was investigated in wild and captive cetaceans from Japan. Antibodies against T. gondii were examined by both latex agglutination test (LAT) and indirect hemagglutination test (IHAT) for 77 serum or plasma samples obtained from 59 individuals of 6 species, including 2 hybrids. Antibody titers greater than 1:64 in LAT and greater than 1:640 in IHAT, indicative of the presence of T. gondii, were found in 11.9% of 59 individuals. In 7 samples that showed a positive reaction by IHAT, T. gondii titers were examined for each immunoglobulin (Ig) fraction separated by sucrose gradient centrifugation. The antibody peaks in each fraction were divided into 3 types, thought to be a reaction of IgM (type 1), IgG (type 2), and IgM with IgG (type 3). Type 1 was found in serum from a bottle-nosed dolphin (Tursiops truncatus) and a killer whale (Orcinus orca) sampled soon after capture off the Japanese coast in 1988; it was concluded that infection in the wild had occurred less than 15 yr before the study was performed. The prevalence of putative IgM and IgG antibodies from a captive-bred T. truncatus suggested that T. gondii infection also occurred in the aquarium.     

Computational verification of anesthesia effect on temperature variations in rabbit eyes exposed to 2.45 GHz microwave energy

This paper computationally verifies the effect of anesthesia on temperature variations in the rabbit eye due to microwave energy. The main reason for this investigation is that our previous paper suggested a reduction in blood flow due to the administration of anesthesia, resulting in an overestimated temperature increase. However, no quantitative investigation has yet been conducted. The finite-difference time-domain (FDTD) method is used for calculating power absorption and temperature variation in rabbits. For this purpose, we used a computational rabbit phantom, which is comprised of 12 tissues (including 6 eye tissues) with a resolution of 1 mm. Thermal constants of the rabbit were derived by comparing measured and calculated temperatures. For intense microwave exposure to the rabbit eye, time courses of calculated and measured temperatures were in good agreement for cases both with and without the administration of anesthesia. The point to be stressed is that under anesthesia the thermoregulatory response was inactivated and blood flow and basal metabolism was reduced.     

Neural correlates of the difference between working memory speed and simple sensorimotor speed: an fMRI study

The difference between the speed of simple cognitive processes and the speed of complex cognitive processes has various psychological correlates. However, the neural correlates of this difference have not yet been investigated. In this study, we focused on working memory (WM) for typical complex cognitive processes. Functional magnetic resonance imaging data were acquired during the performance of an N-back task, which is a measure of WM for typical complex cognitive processes. In our N-back task, task speed and memory load were varied to identify the neural correlates responsible for the difference between the speed of simple cognitive processes (estimated from the 0-back task) and the speed of WM. Our findings showed that this difference was characterized by the increased activation in the right dorsolateral prefrontal cortex (DLPFC) and the increased functional interaction between the right DLPFC and right superior parietal lobe. Furthermore, the local gray matter volume of the right DLPFC was correlated with participants' accuracy during fast WM tasks, which in turn correlated with a psychometric measure of participants' intelligence. Our findings indicate that the right DLPFC and its related network are responsible for the execution of the fast cognitive processes involved in WM. Identified neural bases may underlie the psychometric differences between the speed with which subjects perform simple cognitive tasks and the speed with which subjects perform more complex cognitive tasks, and explain the previous traditional psychological findings.     

Mammalian Atg2 proteins are essential for autophagosome formation and important for regulation of size and distribution of lipid droplets

Macroautophagy is an intracellular degradation system by which cytoplasmic materials are enclosed by the autophagosome and delivered to the lysosome. Autophagosome formation is considered to take place on the endoplasmic reticulum and involves functions of autophagy-related (Atg) proteins. Here, we report the identification and characterization of mammalian Atg2 homologues Atg2A and Atg2B. Simultaneous silencing of Atg2A and Atg2B causes a block in autophagic flux and accumulation of unclosed autophagic structures containing most Atg proteins. Atg2A localizes on the autophagic membrane, as well as on the surface of lipid droplets. The Atg2A region containing amino acids 1723-1829, which shows relatively high conservation among species, is required for localization to both the autophagic membrane and lipid droplet and is also essential for autophagy. Depletion of both Atg2A and Atg2B causes clustering of enlarged lipid droplets in an autophagy-independent manner. These data suggest that mammalian Atg2 proteins function both in autophagosome formation and regulation of lipid droplet morphology and dispersion.     

Sequence Analysis of Amplified DNA Fragments Containing the Region Encoding the Putative Lipase Substrate-Binding Domain and Genotyping of Aeromonas hydrophila

DNA fragments were amplified by PCR from all tested strains of Aeromonas hydrophila, A. caviae, and A. sobria with primers designed based on sequence alignment of all lipase, phospholipase C, and phospholipase A1 genes and the cytotonic enterotoxin gene, all of which have been reported to have the consensus region of the putative lipase substrate-binding domain. All strains showed lipase activity, and all amplified DNA fragments contained a nucleotide sequence corresponding to the substrate-binding domain. Thirty-five distinct nucleotide sequence patterns and 15 distinct deduced amino acid sequence patterns were found in the amplified DNA fragments from 59 A. hydrophila strains. The deduced amino acid sequences of the amplified DNA fragments from A. caviae and A. sobria strains had distinctive amino acids, suggesting a species-specific sequence in each organism. Furthermore, the amino acid sequence patterns appear to differ between clinical and environmental isolates among A. hydrophila strains. Some strains whose nucleotide sequences were identical to one another in the amplified region showed an identical DNA fingerprinting pattern by repetitive extragenic palindromic sequence-PCR genotyping. These results suggest that A. hydrophila, and also A. caviae and A. sobria strains, have a gene encoding a protein with lipase activity. Homologs of the gene appear to be widely distributed in Aeromonas strains, probably associating with the evolutionary genetic difference between clinical and environmental isolates of A. hydrophila. Additionally, the distinctive nucleotide sequences of the genes could be attributed to the genotype of each strain, suggesting that their analysis may be helpful in elucidating the genetic heterogeneity of Aeromonas.