Angiotensin II induces the aggregation of native and oxidized low-density lipoprotein.

Modifications of low-density lipoprotein (LDL), such as oxidation and aggregation, and angiotensin (Ang) peptides are involved in the pathogenesis of atherosclerosis. Here, we investigated the relationship between one of the Ang peptides, AngII, and two LDL modifications, oxidation and aggregation. Using polyacrylamide gel electrophoresis and aggregation assays, we noted that AngII markedly induced the aggregation of LDL and oxidized LDL (Ox-LDL), and bound to both the aggregated and non-aggregated forms. In contrast, a peptide (AngIII) formed by deletion of N-terminal Asp of AngII induced the aggregation of Ox-LDL but not LDL. From tyrosine fluorescence measurements, we noted that AngII interacted with two major lipid components in LDL and Ox-LDL, phosphatidylcholine (PC) and oxidized PC, while AngIII interacted with oxidized PC, but not with PC and lysophosphatidylcholine. Moreover, results from thiobarbituric acid-reactive substances assay proved that AngII did not induce oxidation of LDL. These results suggest that AngII can be involved in the pathogenesis of atherosclerosis by binding to LDL and Ox-LDL-especially to the major lipid components, PC and oxidized PC-followed by inducing the aggregation of LDL and Ox-LDL and that the N-terminal Asp of AngII is important for the binding and aggregation specificity of LDL and Ox-LDL.

A Fluorescence-Labeled Heptapeptide, (FITC)KP6, as an Efficient Probe for the Specific Detection of Oxidized and Minimally Modified Low-Density Lipoprotein.

Two oxidized forms of low-density lipoprotein (LDL), oxidized LDL (ox-LDL) and minimally modified LDL (MM-LDL), are believed to play a major role in the pathogenesis of atherosclerosis. Recently, we reported that a heptapeptide (Lys-Trp-Tyr-Lys-Asp-Gly-Asp, KP6) coupled through the ε-amino group of N-terminus Lys to fluorescein isothiocyanate, (FITC)KP6, bound to ox-LDL but not to LDL. In the present study, we investigated whether (FITC)KP6 could be used as a fluorescent probe for the specific detection of MM-LDL and ox-LDL. Results from polyacrylamide gel electrophoresis and surface plasmon resonance proved that (FITC)KP6 could efficiently bind to MM-LDL as well as ox-LDL in a dose-dependent manner and with high affinity (K D = 3.16 and 3.54 ng/mL protein for MM-LDL and ox-LDL, respectively). (FITC) KP6 bound to lysophosphatidylcholine and oxidized phosphatidylcholine, both present abundantly in ox-LDL and MM-LDL, respectively. In vitro, (FITC)KP6 was detected on the surface and/or in the cytosol of human THP-1-derived macrophages incubated with ox-LDL and MM-LDL, but not LDL. These results suggest that (FITC)KP6 could be an efficient fluorescent probe for the specific detection of ox-LDL and MM-LDL and can therefore contribute to the identification, diagnosis, prevention, and treatment of atherosclerosis.

The evolutionary history of maternal plant-manipulation and larval feeding behaviours in attelabid weevils (Coleoptera; Curculionoidea).

Attelabid weevils manipulate specific structures of their host plants in a species-specific manner, e.g., cutting a shoot, cutting a leaf, rolling a leaf, or constructing sophisticated wrapped leaf rolls, presumably to secure the survivorship of eggs or larvae. To depict the evolutionary history of maternal plant-manipulation behaviours and larval feeding strategies of the family Attelabidae, molecular phylogenetic analyses were conducted by sequencing the nuclear 18S and 28S ribosomal DNA and the mitochondrial cytochrome oxidase subunit I genes. Our analyses indicated that the attelabid weevils form a monophyletic group, and that maternal plant-cutting behaviour originated in a common ancestor of Attelabidae, but was subsequently lost in several lineages. Monophyly of the subfamily Attelabinae was also recovered with high support, but the subfamily Rhynchitinae was not recovered as monophyletic. By employing maximum-likelihood-based ancestral state reconstructions, larval leaf-blade feeding was inferred to have evolved from boring of cut shoots/petioles. Moreover, maternal leaf-rolling behaviours likely originated independently in the Attelabinae and Byctiscini lineages, and in several Deporaini lineages. As the sophisticated behaviours constructing wrapped leaf rolls of Attelabinae originated only once and has not been lost from the lineage, these complex and innovative behaviours may have contributed to the success and diversification of the lineage.

Contradictory effects of leaf rolls in a leaf-mining weevil.

Leaf rolls by herbivorous insects evolved in various lepidopteran groups, aphids, and some attelabid weevil species. Leaf rolls are known to have a positive effect on the survival of immature insects, protecting them from natural enemies such as birds, ants, predatory wasps, and parasitoids as well as environmental stress. On the other hand, leaf rolls are considered to have a negative effect on immature survival, attracting natural enemies because of their noticeability and subsequent learning or specialization. In this study, we directly tested the effects of leaf rolls using an attelabid species by comparing the fate of immature insects between artificial leaf rolls and unrolled leaves. The results showed the following positive effects of leaf rolls: avoidance of parasitism by eulophid wasps and avoidance of egg predation by unknown predators. On the other hand, a negative effect of leaf rolls was also detected, specifically and increase in mortality via leaf roll herbivory. This study indicated that leaf shelters are not only protective refuges but are also sometimes risky hiding places, although total survival rates increased in leaf shelters.

[Electromyographic activity of human triangularis sterni muscles during thoracic rotation].

The triangularis sterni muscles (TS) have been recognized as expiratory muscles, but there is no information on their postural activity or their phasic electromyographic (EMG) activity during thoracic rotation. We examined the EMG activity of the right TS using fine-wire electrodes, in 5 healthy male subjects. With subjects breathing through a mouthpiece, airflow, raw and moving-averaged EMG signals were sampled with a computer during thoracic rotation and resting, accompanied by breathing with or without voluntary thoracic rotation. Maximum EMG (EMGmax) was defined as the greatest moving-averaged EMG activity recorded from each subject during the slow expiratory maneuver from functional residual capacity to residual volume. With leftward thoracic rotation without breathing, the tonic EMG activity of the right TS was observed in all subjects. During resting breathing without thoracic rotation, there were respiration-related phasic activities on TS EMG during expiration in all subjects. With leftward thoracic rotation, the respiration-related phasic activities on TS EMG significantly increased from 8.2 +/- 3.5 (mean +/- SE) %EMGmax to 15.2 +/- 6.1 %EMGmax. On the other hand, with rightward thoracic rotation, it decreased to 3.0 +/- 1.0 %EMGmax. We concluded that 1) TS has a postural function like that of the intercostal muscles, and that 2) the respiratory function of TS is affected by thoracic rotation.

[Case report of pulmonary epithelioid hemangioendothelioma].

A 45-year-old man was admitted to our hospital because of multiple nodular shadows in the right upper field of a chest radiogram taken at a regular medical checkup. He underwent open lung biopsy. The lung tumor found was diagnosed histologically as pulmonary epithelioid hemangioendothelioma. The tumor cells showed positive staining for CD34 and factor VIII-related antigen. Pulmonary epithelioid hemangioendothelioma (PEH) is a rare lung tumor, of which only 40 cases, including the present case, were reported between 1983 and 2002 in Japan. PEH is a progressive, low-grade malignant tumor that originates from hemangioendothelial cells. In chest radiography or CT scanning, PEH is usually discovered incidentally as multiple nodular shadows. Many cases of PEH are diagnosed by open lung biopsy or thoracoscopic biopsy. No standard therapy for PEH has yet been established, other than resection of a solitary lesion. The present patient has been followed without treatment for five-and-a-half years, and is still alive with no symptoms.

An isostructural G-G to A-A substitution within the HIV RRE RNA switches the specificity towards arginine-rich peptides.

The HIV Rev protein utilizes a short alpha-helical arginine-rich RNA-binding domain to bind deeply within the major groove of an internal loop region of the Rev-response element (RRE) RNA. A G48-G71 base-pair which covaries to an isostructural A48-A71 base pair has been shown to play an important structure role in Rev-RRE binding. On the other hand, a high affinity RRE-binding peptide aptamer, the K1 peptide, was shown to have low binding affinity towards the RRE A48-A71 mutant, suggesting that the K1 peptide was recognizing the G48-G71 base-pair. In this study, in an attempt to understand the basis for the recognition of the G48-G71 base-pair by the K1 peptide, the selection of peptides that bind to the RRE A48A71 (RREAA) mutant was carried out. As a result, a peptide specific for the mutant, the LDN1 peptide, was identified. The LDN1 peptide was found to bind to the internal loop region of the RREAA, as in the case of the K1-RRE interaction. However, amino acids important for LDN1-binding to RREAA, were found to be distinct from those important for K1-binding to the RRE. These results demonstrate how subtle changes in RNA structure can dramatically alter the peptide-binding specificity of an RNA.

Plant-pollinator interactions in tropical monsoon forests in Southeast Asia.

Forests with different flora and vegetation types harbor different assemblages of flower visitors, and plant-pollinator interactions vary among forests. In monsoon-dominated East and Southeast Asia, there is a characteristic gradient in climate along latitude, creating a broad spectrum of forest types with potentially diverse pollinator communities. To detect a geographical pattern of plant-pollinator interactions, we investigated flowering phenology and pollinator assemblages in the least-studied forest type, i.e., tropical monsoon forest, in the Vientiane plain in Laos. Throughout the 5-year study, we observed 171 plant species blooming and detected flower visitors on 145 species. Flowering occurred throughout the year, although the number of flowering plant species peaked at the end of dry season. The dominant canopy trees, including Dipterocarpaceae, bloomed annually, in contrast to the supra-annual general flowering that occurs in Southeast Asian tropical rain forests. Among the 134 native plant species, 68 were pollinated by hymenopterans and others by lepidopterans, beetles, flies, or diverse insects. Among the observed bees, Xylocopa, megachilids, and honeybees mainly contributed to the pollination of canopy trees, whereas long-tongued Amegilla bees pollinated diverse perennials with long corolla tubes. This is the first community-level study of plant-pollinator interactions in an Asian tropical monsoon forest ecosystem.