This paper describes a portable measurement system for current signals of an ion channel that is composed of a planar lipid bilayer. A stable and reproducible lipid bilayer is formed in outdoor environments by using a droplet contact method with a micropipette. Using this system, we demonstrated that the single-channel recording of a transmembrane protein (alpha-hemolysin) was achieved in the field at a high-altitude (∼3623 m). This system would be broadly applicable for obtaining environmental measurements using membrane proteins as a highly sensitive sensor. 相似文献
Indigo is an insoluble blue dye historically used for dyeing textiles. A traditional approach for indigo dyeing involves microbial reduction of polygonum indigo to solubilize it under alkaline conditions; however, the mechanism by which microorganisms reduce indigo remains poorly understood. Here, we aimed to identify an enzyme that catalyzes indigo reduction; for this purpose, from alkaline liquor that performed microbial reduction of polygonum indigo, we isolated indigo carmine-reducing microorganisms. All isolates were facultative anaerobic and alkali-tolerant Bacillus spp. An isolate termed AO1 was found to be an alkaliphile that preferentially grows at pH 9.0–11.0 and at 30–35 °C. We focused on flavin-dependent azoreductase as a possible enzyme for indigo carmine reduction and identified its gene (azoA) in Bacillus sp. AO1 using homology-based strategies. azoA was monocistronic but clustered with ABC transporter genes. Primary sequence identities were < 50% between the azoA product (AzoA) and previously characterized flavin-dependent azoreductases. AzoA was heterologously produced as a flavoprotein tolerant to alkaline and organic solvents. The enzyme efficiently reduced indigo carmine in an NADH-dependent manner and showed strict specificity for electron acceptors. Notably, AzoA oxidized NADH in the presence, but not the absence, of indigo. The reaction rate was enhanced by adding organic solvents to solubilize indigo. Absorption spectrum analysis showed that indigo absorption decreased during the reaction. These observations suggest that AzoA can reduce indigo in vitro and potentially in Bacillus sp. AO1. This is the first study that identified an indigo reductase, providing a new insight into a traditional approach for indigo dyeing.
Extremophiles - A gene-encoding a dye-linked d-lactate dehydrogenase (Dye-DLDH) homolog was identified in the genome of the hyperthermophilic archaeon Thermoproteus tenax. The gene was expressed in... 相似文献
This is the first report on the annual egg production patterns in mature termite colonies in the field. Data on the seasonal
patterns of egg production in field colonies are very important for understanding the annual colony growth schedule, resource
allocation, and population dynamics of the termites. However, collecting the eggs from a sufficient number of colonies is
extremely difficult in Reticulitermes termites because their multiple-site nesting makes it difficult to find the reproductive center of the colonies. Here, we
first show the seasonal pattern of egg production in the subterranean termite Reticulitermes speratus by collecting the reproductive center of ten colonies each month from April through October. We had to destructively examine
dozens of nests to find eggs from enough field colonies each month. Mature field colonies began to produce eggs in late May,
soon after the swarming season, and the egg production rate (EPR) reached its maximum in early July. The eggs hatched until
late October. The EPR was significantly correlated with the average monthly temperature. Additional investigation of the egg
distributions in the nests showed that most eggs were kept around the royal cell, which contained the reproductives. The largest
colony had 109 supplemental queens and 94,023 eggs, suggesting that each queen produced an average of 24.7 eggs per day, based
on the known mean hatching period of an inseminated egg of 34.95±0.12 (SE) days. 相似文献
Numerous termite species have been introduced outside their native ranges by human transport, and some have become invasive. The dampwood termite Zootermopsis nevadensis (Hagen), which is native to western North America, has been introduced to and become established in Kawanishi City, Hyogo Prefecture, Japan. Zootermopsis nevadensis is subdivided into two subspecies based on cuticular hydrocarbon (CHC) phenotypes: Z. nevadensis nevadensis and Z. nevadensis nuttingi (Haverty and Thorne). Here, we identified Z. nevadensis in Japan as hybrids between the two subspecies. Chemical analysis showed the presence of 7,15-dimethylhenicosane and 5,17-dimethylhenicosane in the CHCs of Z. nevadensis in Japan, corresponding to the CHC phenotype of Z. n. nevadensis. Conversely, all mitochondrial cytochrome c oxidase subunit I sequences of Z. nevadensis in Japan were identical to sequences from Z. n. nuttingi and hybrids between the two subspecies from a native hybrid zone in California, USA. In addition, phylogenetic analysis showed that Z. nevadensis in Japan formed a clade with Z. n. nuttingi and hybrids between the two subspecies. Our results show discordance between the chemical and genetic features of Z. nevadensis in Japan, indicating that individuals of Z. nevadensis in Japan are hybrids between the two subspecies. 相似文献
Emergence of multi-drug resistant HIV-1 is a serious problem for AIDS treatment. Recently, the virus-cell membrane fusion process has been identified as a promising target for the development of novel drugs against these resistant variants. In this study, we identified a 29-residue peptide fusion inhibitor, SC29EK, which shows activity comparable to the previously reported inhibitor SC35EK. Some residues in SC29EK not required for interaction with virus gp41 heptad repeat 1 (HR1) were replaced with a non-proteinogenic amino acid, 2-aminoisobutyric acid (Aib), to stabilize the alpha-helix structure and to provide resistance to peptidases. 相似文献
Peptide tags containing tyrosines (Y-tag) were introduced at the C-terminus of a hyperthermophilic enzyme, alkaline phosphatase from Pyrococcusfuriosus (PfuAP). Immobilization of the recombinant PfuAPs onto water-in-oil-in-water (W/O/W) type microcapsules was performed by
an in situ polymerization method. All the recombinant PfuAPs prepared in this study were quantitatively immobilized onto microcapsules.
The PfuAP-immobilized microcapsules showed no significant loss of enzymatic activity until the 5th round of assays. This result
implies that the recombinant PfuAPs were covalently immobilized onto microcapsules. Immobilized PfuAP tagged with a Y-tag
having the sequence GGYYY exhibited approximately a twofold higher catalytic activity compared with the wild-type PfuAP.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献