Enterostatin (APGPR) suppresses the analgesic activity of morphine by a CCK-dependent mechanism

Enterostatin (APGPR) found in the gastrointestinal tract and brain is an anorectic pentapeptide. We found that APGPR inhibited morphine-induced analgesia after intracerebroventricular administration in mice at a dose of 10nmol/mouse. The anti-analgesic effect of APGPR was inhibited by pretreatment with lorglumide and LY225910, antagonists for cholecystokinin 1 (CCK1) and cholecystokinin 2 (CCK2) receptors, respectively. The anti-analgesic effect of APGPR may be mediated by CCK release, since APGPR does not have affinity for CCK receptors.     

Temporal and quantitative analysis of expression of metalloproteinases (MMPs) and their endogenous inhibitors in atherosclerotic lesions

Matrix metalloproteinases (MMPs) play an important role in the pathogenesis of vascular diseases, such as atherosclerosis, plaque rupture and aneurysms. Although several MMPs have been demonstrated in the lesions of atherosclerosis, their expression profiles during the initiation and progression of lesions have not been fully determined. We hypothesized that the expression of various MMPs, along with their endogenous inhibitors, may be differentially regulated dependent upon the lesion progression. Therefore, we made a temporal and quantitative analysis of the mRNA and protein expression of MMPs and tissue inhibitors of metalloproteinases expressed in the different stages of atherosclerotic lesions of rabbits and humans. We found that MMP-1, MMP-12 and MMP-13 expression was nearly absent in the normal arterial wall, but was remarkably increased with lesion progression. Furthermore, the expression of these MMPs in the lesions was closely associated with intimal macrophages and monocyte chemoattractant protein-1 expression, suggesting that the intimal macrophages are the major source of production of these MMPs. MMP-3 and MT1-MMP were also significantly upregulated in the early-stage lesions and fatty streaks compared to the normal aortas of rabbits. Our results indicate that MMP-1, -12, and -13 derived from intimal macrophages may play a pivotal role in both lesion initiation and progression, and therefore are potential therapeutic targets for the treatment of plaque rupture and aneurysm formation.     

Classification of the possible pairs between the first anticodon and the third codon positions based on a simple model assuming two geometries with which the pairing effectively potentiates the decoding complex

Crick's wobble theory states that some specific pairs between the bases at the first position of the anticodon (position 34) and the third position of the codon (position III) are allowed and the others are disallowed during the correct codon recognition. However, later researches have shown that the pairing rule, or the wobble rule, is different from the supposed one. Despite the continuing efforts including computer-aided model building studies and analyses of three-dimensional structures in the crystals of the ribosomes, the structural backgrounds of the wobble rule are still unclear. Here, I classify the possible pairs into 6 classes according to the increases accompanying the formation of the pairs in the potential productivity of the decoding complex on the basis of a simple model that was originally proposed previously and is refined here. In the model, the conformation with the base at position 34 displaced toward the minor groove side from the position for the Watson-Crick pairs is supposed to be equivalent to the conformation with the Watson-Crick pairs. It is also reasoned and supposed that some weak pairs may sometimes be allowed depending on the structural context. It is demonstrated that most of the experimental results reported so far are consistent with the model. I discuss on which experimental facts can be reasoned with the model and which need further explanations. I expect that the model will be a good basis for further understanding of the wobble rule and its structural backgrounds.     

Sequential immunization with V3 peptides from primary human immunodeficiency virus type 1 produces cross-neutralizing antibodies against primary isolates with a matching narrow-neutralization sequence motif

An antibody response capable of neutralizing not only homologous but also heterologous forms of the CXCR4-tropic human immunodeficiency virus type 1 (HIV-1) MNp and CCR5-tropic primary isolate HIV-1 JR-CSF was achieved through sequential immunization with a combination of synthetic peptides representing HIV-1 Env V3 sequences from field and laboratory HIV-1 clade B isolates. In contrast, repeated immunization with a single V3 peptide generated antibodies that neutralized only type-specific laboratory-adapted homologous viruses. To determine whether the cross-neutralization response could be attributed to a cross-reactive antibody in the immunized animals, we isolated a monoclonal antibody, C25, which neutralized the heterologous primary viruses of HIV-1 clade B. Furthermore, we generated a humanized monoclonal antibody, KD-247, by transferring the genes of the complementary determining region of C25 into genes of the human V region of the antibody. KD-247 bound with high affinity to the "PGR" motif within the HIV-1 Env V3 tip region, and, among the established reference antibodies, it most effectively neutralized primary HIV-1 field isolates possessing the matching neutralization sequence motif, suggesting its promise for clinical applications involving passive immunizations. These results demonstrate that sequential immunization with B-cell epitope peptides may contribute to a humoral immune-based HIV vaccine strategy. Indeed, they help lay the groundwork for the development of HIV-1 vaccine strategies that use sequential immunization with biologically relevant peptides to overcome difficulties associated with otherwise poorly immunogenic epitopes.     

Recent expansion of the telomeric complex in rodents: Two distinct POT1 proteins protect mouse telomeres

Human telomeres are protected by shelterin, a complex that includes the POT1 single-stranded DNA binding protein. We found that mouse telomeres contain two POT1 paralogs, POT1a and POT1b, and we used conditional deletion to determine their function. Double-knockout cells showed that POT1a/b are required to prevent a DNA damage signal at chromosome ends, endoreduplication, and senescence. In contrast, POT1a/b were largely dispensable for repression of telomere fusions. Single knockouts and complementation experiments revealed that POT1a and POT1b have distinct functions. POT1a, but not POT1b, was required to repress a DNA damage signal at telomeres. Conversely, POT1b, but not POT1a, had the ability to regulate the amount of single-stranded DNA at the telomere terminus. We conclude that mouse telomeres require two distinct POT1 proteins whereas human telomeres have one. Such divergence is unprecedented in mammalian chromosome biology and has implications for modeling human telomere biology in mice.     

Genetic variants of the IgA Fc receptor (FcαR, CD89) promoter in chronic hepatitis C patients

Fc receptor for IgA (FcαR, CD89) is capable of triggering IgA-mediated immune responses to pathogens and has been proposed to function in circulating IgA clearance. Because inheritable variations modifying individual immune responses or immunoglobulin catabolism may affect the chronicity of viral infection, we investigated whether promoter polymorphisms of the FcαR gene (FCAR) affect chronic hepatitis C virus (HCV) infection and its disease progression. The two −311T/C and −142T/C single-nucleotide polymorphisms (SNPs) were studied by direct DNA sequencing in 177 Japanese patients with chronic hepatitis C (CHC). Both −311CC and −142CC genotypes were more frequent in CHC patients (15.9 and 18.6%) compared with 210 healthy controls (5.7 and 10.0%) [p = 0.001, odds ratio (OR) = 3.10, 95% confidence interval CI) = 1.53–6.30 and p = 0.014, OR = 2.06, 95% CI = 1.14–3.72, respectively], and were associated with infection with HCV genotype 2a/2b (p = 0.019 and p = 0.005, respectively). Conversely, −311CC and −142CC were decreased in 59 patients at advanced stages of disease as assessed on the basis of hepatic fibrosis markers such as decreased platelet count (PLT) ( < 150,000/μl) (5.1 and 8.5%) compared with 91 patients with normal PLT ( ≥ 150,000/μl) (24.2 and 26.4%) (p = 0.006 and p = 0.005, respectively). Moreover, among the patients with normal PLT (but not with decreased PLT), −311CC or −142CC was significantly associated with decreased serum IgA levels (p = 0.023 or p = 0.007, respectively). These results suggest that the FCAR promoter SNPs may be related to chronic HCV infection and disease progression in Japanese CHC, which might be explained by altered FcαR expression affecting IgA-mediated immune responses and/or IgA catabolism.     

Host-symbiont relationships in hydrothermal vent gastropods of the genus Alviniconcha from the Southwest Pacific

Hydrothermal vent gastropods of the genus Alviniconcha are unique among metazoans in their ability to derive their nutrition from chemoautotrophic gamma- and epsilon-proteobacterial endosymbionts. Although host-symbiont relationships in Alviniconcha gastropods from the Central Indian Ridge in the Indian Ocean and the Mariana Trough in the Western Pacific have been studied extensively, host-symbiont relationships in Alviniconcha gastropods from the Southwest Pacific remain largely unknown. Phylogenetic analysis using mitochondrial cytochrome c oxidase subunit I gene sequences of host gastropods from the Manus, North Fiji, and Lau Back-Arc Basins in the Southwest Pacific has revealed a new host lineage in a Alviniconcha gastropod from the Lau Basin and the occurrence of the host lineage Alviniconcha sp. type 2 in the Manus Basin. Based on 16S rRNA gene sequences of bacterial endosymbionts, two gamma-proteobacterial lineages and one epsilon-proteobacterial lineage were identified in the present study. The carbon isotopic compositions of the biomass and fatty acids of the gastropod tissues suggest that the gamma- and epsilon-proteobacterial endosymbionts mediate the Calvin-Benson cycle and the reductive tricarboxylic acid cycle, respectively, for their chemoautotrophic growth. Coupling of the host and symbiont lineages from the three Southwest Pacific basins revealed that each of the Alviniconcha lineages harbors different bacterial endosymbionts belonging to either the gamma- or epsilon-Proteobacteria. The host specificity exhibited in symbiont selection provides support for the recognition of each of the host lineages as a distinct species. The results from the present study also suggest the possibility that Alviniconcha sp. types 1 and 2 separately inhabit hydrothermal vent sites approximately 120 m apart in the North Fiji Basin and 500 m apart in the Manus Basin.     

Genotypic difference in canopy diffusive conductance measured by a new remote-sensing method and its association with the difference in rice yield potential

There have been few practical ways of measuring physiological determinants of rice yield. Rapid evaluation of yield determination traits may expedite breeding of high-yielding rice. Here, we report a new remote-sensing technique for the evaluation of canopy ecophysiological status under field conditions developed based on simultaneous measurements of sunlit and suddenly shaded canopy temperatures. This technique has the advantage of instantaneous estimation of aerodynamic resistance (r(a)) and canopy diffusive resistance (r(c) without measuring wind velocity. Canopy diffusive conductance (1 / r(c)) estimated by the remote sensing method was closely related to leaf stomatal conductance (g(s)) measured with a portable gas exchange system. This result supported the validity of this new method for quantitative estimation of canopy physiological characteristics. Significant genotypic differences were obtained in canopy-air temperature difference (Tc-Ta), r(c) and 1 / r(c) during the 2-week period preceding full heading for two years, and 1 / r(c) was highly correlated with crop growth rate (CGR), which was closely related to the final yield. These results suggest that 1 / r(c) can be an effective criterion for the selection of high-yielding rice genotypes, and the remote sensing technique proposed here can be a powerful tool for the rapid evaluation of 1 / r(c) under field conditions.     

Expression of versican and ADAMTS1, 4, and 5 during bone development in the rat mandible and hind limb.

Extracellular matrix (ECM) remodeling is achieved by both production and degradation of ECM molecules during bone development. ADAMTS (a disintegrin and metalloprotease with thrombospondin type 1 motifs) constitutes a family of extracellular proteases which are implicated in cleaving the protein versican. The present study was designed to investigate the expression of versican and ADAMTS1, 4, and 5 mRNA during bone development in rat mandibles and hind limbs by RT-PCR and in situ hybridization. Versican was localized by immunohistochemistry. The process of bone development from day 14 postcoitum through week 6 postnatum was divided into the beginning of osteogenesis, woven bone, and lamellar bone stages. Versican protein was abundant in the woven bone matrix, but decreased in the lamellar bone matrix. Versican mRNA was prominent in some osteoblasts with corresponding localization of the cognate protein. The temporal and spatial mRNA expression pattern of ADAMTS1, 4, and 5 was comparable to that of versican. These results suggest that woven bone rich in versican alters into lamellar bone containing little versican during bone development in both mandibles and hind limbs, where some osteoblasts may be involved in production as well as degradation of versican by secreting ADAMTS1, 4, and 5.