Effects of longitudinal stretch on VSM tone and distensibility of muscular conduit arteries

With progressing age, large arteries diminish their longitudinal stretch, which in extreme cases results in tortuosity. Increased age is also associated with loss of vessel distensibility. We measured pressure-diameter curves from muscular porcine carotid arteries ex vivo at different longitudinal stretch ratios (lambda(z) = 1.4 and 1.8) and under different vascular smooth muscle (VSM) conditions (fully relaxed, normal VSM tone, and maximally contracted). Distensibility was found to be halved by decreasing longitudinal stretch from lambda(z) = 1.8 to 1.4 at physiological pressures. This counterintuitive observation is possible because highly nonlinear elastic modulus of the artery and anisotropic properties. Furthermore, a significantly larger basal VSM contraction was observed at lambda(z) = 1.8 than 1.4, although this was clearly not related to a myogenic response during inflation. This dependence of VSM tone to longitudinal stretch may have possible implications on the functional characteristics of the arterial wall.     

Microdischarge‐Based Direct Current Triboelectric Nanogenerator via Accumulation of Triboelectric Charge in Atmospheric Condition

Direct conversion of mechanical energy into direct current (DC) by triboelectric nanogenerators (TENGs) is one of the desired features in terms of energy conversion efficiency. Although promising applications have been reported using the triboelectric effect, effective DC generating TENGs must be developed for practical purposes. Here, it is reported that continuous DC generation within a TENG itself, without any circuitry, can be achieved by triggering air breakdown via triboelectrification. It is demonstrated that DC generation occurs in combination with i) charge accumulation to generate air breakdown, ii) incident discharge (microdischarge), and iii) conveyance of charges to make the device sustainable. 10.5 mA m^?2 of output current and 10.6 W m^?2 of output power at 33 MΩ load resistance are achieved. Compared to the best DC generating TENGs ever reported, the TENG in this present study generates about 20 times larger root‐mean square current density.     

Antioxidative activities of histidine containing caffeic acid-dipeptides

Antioxidants have been utilized in both the food and cosmetics industries to neutralize the activities of reactive oxygen species (ROS) and free radicals. Histidine-containing peptides are powerful antioxidants that exist in nature. Additionally, hydroxycinnamic acid (HCA)-peptide conjugates exhibit a synergistically enhanced antioxidative activity. Thus, caffeic acid (CA), a natural antioxidant, was conjugated to histidine-containing dipeptides (His dipeptides) in order to develop better antioxidants. The antioxidative activities were measured using 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test and lipid peroxidation test with ferric thiocyanate method. Some of the CA-His dipeptides exhibited better radical scavenging activities than CA, and all of the CA-His dipeptides showed enhanced lipid peroxidation inhibitory activities. His dipeptide enhanced the antioxidative activity of CA, and the position of histidine also affected the antioxidative activity of the compounds. CA-proline-histidine amide (CA-Pro-His-NH₂) exhibited the highest activity in both the free radical scavenging test and the lipid peroxidation inhibition test.     

Genetic relatedness in wintering groups of house sparrows (Passer domesticus)

Social behaviour of group-living animals is often influenced by the relatedness of individuals, thus understanding the genetic structure of groups is important for the interpretation of costs and benefits of social interactions. In this study, we investigated genetic relatedness in feeding aggregations of free-living house sparrows ( Passer domesticus ) during the nonbreeding season. This species is a frequent model system for studies of social behaviour (e.g. aggression, social foraging), but we lack adequate information on the kin structure of sparrow flocks. During two winters, we ringed and observed sparrows at feeding stations, and used resightings to identify stable flock-members and to calculate association indices between birds. We genotyped the birds using seven highly polymorphic microsatellite loci, and estimated pairwise relatedness coefficients and relatedness categories (close kin vs. unrelated) by maximum likelihood method. We found that most birds were unrelated to each other in the flocks (mean ± SE relatedness coefficient: 0.06 ± 0.002), although most individuals had at least a few close relatives in their home flock (14.3 ± 0.6% of flock-mates). Pairwise association between individuals was not significantly related to their genetic relatedness. Furthermore, there was no difference between within-flock vs. between-flock relatedness, and birds had similar proportions of close kin within and outside their home flock. Finally, relatedness among members of different flocks was unrelated to the distance between their flocks. Thus, sparrow flocks were not characterized by association of relatives, nevertheless the presence of some close kin may provide opportunity for kin-biased behaviours to evolve.     

The cytologic diagnosis of Mycobacterium kansasi tuberculosis by fluorescence microscopy of Papanicolaou-stained specimens

The cytologic diagnosis of Mycobacterium kansasi tuberculosis by fluorescence microscopy of Papanicolaou-stained specimens
The sensitivities of (i) Papanicolaou fluorescence, (ii) auramine rhodamine fluorescence, and (iii) Ziehl-Neelsen staining were compared for their ability to detect the atypical mycobacterium Myco. kansasi in cytological samples. Ninety-two cases were investigated, and the sensitivities of the three methods of detection were found to be 36.9%, 12.0%, and 20.7%, respectively. The control groups consisted of 30 specimens from cases of bronchial carcinoma and 30 of pneumonia. All cases were proved by microbiology. No false-positive results were recorded using Papanicolaou fluorescence. An important but coincidental finding arising from this study was that infection by the atypical mycobacterium Myco. kansasi causes cytological patterns corresponding to those normally associated with acute pneumonia and not to tuberculosis.     

Vibrio harveyi Nitroreductase Is Also a Chromate Reductase

The chromate reductase purified from Pseudomonas ambigua was found to be homologous with several nitroreductases. Escherichia coli DH5α and Vibrio harveyi KCTC 2720 nitroreductases were chosen for the present study, and their chromate-reducing activities were determined. A fusion between glutathione S-transferase (GST) and E. coli DH5α NfsA (GST-EcNfsA), a fusion between GST and E. coli DH5α NfsB (GST-EcNfsB), and a fusion between GST and V. harveyi KCTC 2720 NfsA (GST-VhNfsA) were prepared for their overproduction and easy purification. GST-EcNfsA, GST-EcNFsB, and GST-VhNFsA efficiently reduced nitrofurazone and 2,4,6-trinitrotoluene (TNT) as their nitro substrates. The K_m values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 11.8, 23.5, and 5.4 μM, respectively. The V_max values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA were 3.8, 3.9, and 10.7 nmol/min/mg of protein, respectively. GST-VhNfsA was the most effective of the three chromate reductases, as determined by each V_max/K_m value. The optimal temperatures of GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 55, 30, and 30°C, respectively. Thus, it is confirmed that nitroreductase can also act as a chromate reductase. Nitroreductases may be used in chromate remediation. GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA have a molecular mass of 50 kDa and exist as a monomer in solution. Thin-layer chromatography showed that GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA contain FMN as a cofactor. GST-VhNfsA reduced Cr(VI) to Cr(III). Cr(III) was much less toxic to E. coli than Cr(VI).     

The Arabidopsis small G protein ROP2 is activated by light in guard cells and inhibits light-induced stomatal opening

ROP small G proteins function as molecular switches in diverse signaling processes. Here, we investigated signals that activate ROP2 in guard cells. In guard cells of Vicia faba expressing Arabidopsis thaliana constitutively active (CA) ROP2 fused to red fluorescent protein (RFP-CA-ROP2), fluorescence localized exclusively at the plasma membrane, whereas a dominant negative version of RFP-ROP2 (DN-ROP2) localized in the cytoplasm. In guard cells expressing green fluorescent protein-ROP2, the relative fluorescence intensity at the plasma membrane increased upon illumination, suggesting that light activates ROP2. Unlike previously reported light-activated factors, light-activated ROP2 inhibits rather than accelerates light-induced stomatal opening; stomata bordered by guard cells transformed with CA-rop2 opened less than controls upon light irradiation. When introduced into guard cells together with CA-ROP2, At RhoGDI1, which encodes a guanine nucleotide dissociation inhibitor, inhibited plasma membrane localization of CA-ROP2 and abolished the inhibitory effect of CA-ROP2 on light-induced stomatal opening, supporting the negative effect of active ROP2 on stomatal opening. Mutant rop2 Arabidopsis guard cells showed phenotypes similar to those of transformed V. faba guard cells; CA-rop2 stomata opened more slowly and to a lesser extent, and DN-rop2 stomata opened faster than wild-type stomata in response to light. Moreover, in rop2 knockout plants, stomata opened faster and to a greater extent than wild-type stomata in response to light. Thus, ROP2 is a light-activated negative factor that attenuates the extent of light-induced changes in stomatal aperture. The inhibition of light-induced stomatal opening by light-activated ROP2 suggests the existence of feedback regulatory mechanisms through which stomatal apertures may be finely controlled.     

Fine mapping of Grh1, a major gene associated with antibiosis to green rice leafhopper in rice

Green rice leafhopper (GRH, Nephotettix cincticeps Uhler) is one of the insect pests that damage cultivated rice in East Asia. GRH also transmits viruses such as rice dwarf virus. The mortality of GRH nymphs is high in rice cultivar Shingwang, indicating that Shingwang is resistant to GRH. Genetic analyses were performed to map GRH resistance in Shingwang using F2 and F3 populations derived from a cross between a GRH-resistant near-isogenic line (NIL-IS60) from Shingwang and recurrent parent Ilpum. Resistance to GRH in Shingwang was found to be controlled by a single dominant gene (Grh1) mapped within an approximately 670-kb region between 8.10 and 8.77 Mb on the short arm of chromosome 5. Genotypes with three simple sequence repeat markers (RM18166, RM516, and RM18171) and one indel marker (Indel 15040) co-segregated with GRH resistance controlled by the Grh1 locus. A detailed map of the Grh1 locus will facilitate marker-assisted selection of resistance to GRH in rice breeding.