Amino acid sequence of galactosamine-containing glycopeptides in the hinge region of a human immunoglobulin D

Amino acid sequence and the location of seven galactosamine oligosaccharide moieties of the hinge region of the δ chain of human IgD NIG-65 have been determined. These oligosaccharide moieties are distributed in two distinct fashions: 1) three clusters each consisting of five amino acid residues with two consecutive attachment sites either Ala-X-Ala-Ser-Ser or Ala-X-Ala-Thr-Thr, where X can be any amino acid including proline, 2) one triplet sequence Val-Pro-Thr with one attachment site. We propose two rules with regard to the acceptor sequence for galactosamine oligosaccharides, the quintet sequence rule and triplet sequence rule.     

Insulin-like growth factor 1 regulation of proliferation and differentiation of <Emphasis Type="Italic">Xenopus laevis</Emphasis> myogenic cells in vitro

To understand the mechanism of muscle remodeling during Xenopus laevis metamorphosis, we examined the in vitro effect of insulin-like growth factor 1 (IGF-1) on growth and differentiation of three different-fate myogenic cell populations: tadpole tail, tadpole dorsal, and young adult leg muscle. IGF-1 promoted growth and differentiation of both tail and leg myogenic cells only under conditions where these cells could proliferate. Inhibition of cell proliferation by DNA synthesis inhibitor cytosine arabinoside completely canceled the IGF-1’s cell differentiation promotion, suggesting the possibility that IGF-1’s differentiation-promotion effect is an indirect effect via IGF-1’s cell proliferation promotion. IGF-1 promoted differentiation dose dependently with maximum effect at 100–500 ng/ml. RT-PCR analysis revealed the upregulation (11-fold) of ifg1 mRNA expression in developing limbs, suggesting that IGF-1 plays a role in promoting muscle differentiation during limb development. The combined effect of triiodo-l-thyronine (T₃) and IGF-1 was also examined. In adult leg cells, IGF-1 promoted growth and differentiation irrespective of the presence of T₃. In larval tail cells, cell count was 76% lower in the presence of T₃, and IGF-1 did not promote proliferation and differentiation in T₃-containing medium. In larval dorsal cells, cell count was also lower in the presence of T₃, but IGF-1 enhanced proliferation and differentiation in T₃-containing medium. This result is likely due to the presence among dorsal cells of both adult and larval types (1:1). Thus, IGF-1 affects only adult-type myogenic cells in the presence of T₃ and helps accelerate dorsal muscle remodeling during metamorphosis.     

Purification and Some Properties of Two Cα-dehydrogenases Oxidizing Dimeric Lignin Model Compounds from Pseudomonas sp. TMY1009

Two NAD-dependent dehydrogenases which oxidize secondary alcoholic groups at the C_α position of dimeric lignin model compounds were purified from Pseudomonas sp. TMY1009. These enzymes have been designated C_α-dehydrogenase I and II (DH-I and DH-II). DH-II was purified to electrophoretic homogeneity. The molecular weight of DH-II, which is composed of four identical subunits, is 125,000. DH-I was partially purified and the molecular weight of DH-I is 94,000. Both DH-I and DH-II are active for three kinds of dimeric lignin model compounds related to major lignin substructures, although their specificities and affinities are different.     

Comparative study on the behavioral response to starvation in three species of antlion larvae (Neuroptera: Myrmeleontidae)

To clarify how pit-building antlion larvae behave during prolonged periods of low resource abundance, pit relocation rate, giving-up time, and respiration rate under starvation conditions were examined, using three species of antlion larvae. Most larvae ofMyrmeleon bore never relocated their pits before they starved to death, while larvae ofHagenomyia micans relocated more often thanMyrmeleon formicarius (average number of pit relocations 0.04 forM. bore, 0.19 forM. formicarius, and 0.62/individual/10 days forH. micans). The relative respiration rate, a ratio of respiration rate at starvation to that at satiation, was lower inM. bore andM. formicarius than in H. micans. Thus, there was an inversely proportional relationship between the pit relocation rate and the decrease in respiration rate under starvation conditions in the three species of antlion larvae.     

Intrinsic Dynamics of Restriction Endonuclease EcoO109I Studied by Molecular Dynamics Simulations and X-Ray Scattering Data Analysis

EcoO109I is a type II restriction endonuclease that functions as a dimer in solution. Upon DNA binding to the enzyme, the two subunits rotate counterclockwise relative to each other, as the two catalytic domains undergo structural changes to capture the cognate DNA. Using a 150-ns molecular dynamics simulation, we investigated the intrinsic dynamics of the DNA-free enzyme in solution to elucidate the relationship between enzyme dynamics and structural changes. The simulation revealed that the enzyme is considerably flexible, and thus exhibits large fluctuations in the radius of gyration. The small-angle x-ray scattering profile calculated from the simulation, including scattering from explicit hydration water, was in agreement with the experimentally observed profile. Principal component analysis revealed that the major dynamics were represented by the open-close and counterclockwise motions: the former is required for the enzyme to access DNA, whereas the latter corresponds to structural changes upon DNA binding. Furthermore, the intrinsic dynamics in the catalytic domains were consistent with motions capturing the cognate DNA. These results indicate that the structure of EcoO109I is intrinsically flexible in the direction of its functional movement, to facilitate effective structural changes for sequence-specific DNA recognition and processing.     

Epidermal CCR6+ γδ T cells are major producers of IL-22 and IL-17 in a murine model of psoriasiform dermatitis

Cytokine components of Th17 pathway play vital roles in human psoriasis. Although much is known about TCR αβ T cells in psoriasis, the role of unconventional T cells, including γδ T cells, is unclear. In this study, using an IL-23 skin injection model of psoriasiform dermatitis in mice, we demonstrate that IL-22, IL-17A, and the IL-23R were highly enriched in a population of CCR6(+), TCR γδ-low expressing (GDL) T cells that accumulated in the epidermis after IL-23 injections. GDL cells were distinct from resident TCR γδ-high, Vγ3(+),CCR6(-) T cells in the epidermis that did not change appreciably in numbers following IL-23 injection. Large numbers of CCR6(+) cells were detected at or above the level of the epidermal basement membrane by confocal microscopy 5 d after repeated IL-23 injections at the same time GDL cells increased in numbers in the epidermis. TCR δ-deficient mice (lacking γδ T cells) exhibited decreased ear swelling and downregulated expression of IL-22 and IL-17A in the epidermis following IL-23 injection. Our data suggest that a subset of γδ T cells play a critical role in IL-23-mediated psoriasiform dermatitis.     

G146V mutation at the hinge region of actin reveals a myosin class-specific requirement of actin conformations for motility

The G146V mutation in actin is dominant lethal in yeast. G146V actin filaments bind cofilin only minimally, presumably because cofilin binding requires the large and small actin domains to twist with respect to one another around the hinge region containing Gly-146, and the mutation inhibits that twisting motion. A number of studies have suggested that force generation by myosin also requires actin filaments to undergo conformational changes. This prompted us to examine the effects of the G146V mutation on myosin motility. When compared with wild-type actin filaments, G146V filaments showed a 78% slower gliding velocity and a 70% smaller stall force on surfaces coated with skeletal heavy meromyosin. In contrast, the G146V mutation had no effect on either gliding velocity or stall force on myosin V surfaces. Kinetic analyses of actin-myosin binding and ATPase activity indicated that the weaker affinity of actin filaments for myosin heads carrying ADP, as well as reduced actin-activated ATPase activity, are the cause of the diminished motility seen with skeletal myosin. Interestingly, the G146V mutation disrupted cooperative binding of myosin II heads to actin filaments. These data suggest that myosin-induced conformational changes in the actin filaments, presumably around the hinge region, are involved in mediating the motility of skeletal myosin but not myosin V and that the specific structural requirements for the actin subunits, and thus the mechanism of motility, differ among myosin classes.     

Induction of apoptosis in DLD-1 human colon cancer cells by peridinin isolated from the dinoflagellate, Heterocapsa triquetra

Peridinin, which is uniquely present in dinoflagellates, is one of the most abundant carotenoids found in nature. We evaluated the apoptotic effect of peridinin on DLD-1 human colorectal cancer cells. Peridinin significantly reduced the cell viability in a dose-dependent manner (0-20 microM) and induced apoptosis by activating both caspase-8 and caspase-9. Our findings could be important for the high-performance utilization of marine bioproducts.     

Frequent nonrandom shifts in the temporal sequence of developmental landmark events during teleost evolutionary diversification

Morphological transformations can be generated by evolutionary changes in the sequence of developmental events. In this study, we examined the evolutionary dynamics of the developmental sequence on a macroevolutionary scale in teleosts. Using the information from previous reports describing the development of 31 species, we extracted the developmental sequences of 19 landmark events involving the formation of phylogenetically conserved body parts; we then inferred ancestral developmental sequences by two different parsimony‐based methods—event‐pairing and continuous analysis. The phylogenetic comparisons of these sequences revealed event‐dependent heterogeneity in the frequency of sequence changes. Most of the sequence changes occurred as exchanges of temporally neighboring events. These heterochronic changes in developmental sequences accumulated along evolutionary time, but the precise distribution of the changes over the teleostean phylogeny remains unclear due to technical limitations.     

Do the Japanese feel more suspicious about cancer registration than the British?

Background: Cancer registration is indispensable, providing useful statistical measures for the appropriate evaluation of cancer control programs and medical treatment or screening. Methods: Following the British national survey on attitudes toward cancer registration, we conducted an investigation to correctly evaluate the general opinion of the Japanese population in this regard. We randomly recruited 3000 men and women aged 20–69 years from a research database. Results: Only 4% of all respondents had heard about the cancer registry system before the investigation. However, 77% of respondents thought that cancer registration was useful. Forty-three percent of respondents answered, regardless of the strictness of the data protection, that privacy had been violated if the registration occurred without an individual explanation. Compared with the British survey results, Japanese people seemed to be more suspicious about the largely unknown system of cancer registry. Nonetheless, it is noteworthy that Japanese respondents did not show active opposition to cancer registration; they tended to choose “I don’t know” instead of “no” to questions asking if they supported the registry system. Multivariate analysis showed that male sex, older age, and living in the southern region were the factors significantly associated with support for cancer registration. Conclusions: We can seek society's understanding toward cancer registration by actively utilizing information from cancer registries, by using examples of how data are actually used that have wide appeal, and by educating the public on how the data are treated under the complete privacy policy.