Collagen XXIV,a vertebrate fibrillar collagen with structural features of invertebrate collagens: selective expression in developing cornea and bone

Tissue-specific assembly of fibers composed of the major collagen types I and II depends in part on the formation of heterotypic fibrils, using the quantitatively minor collagens V and XI. Here we report the identification of a new fibrillar-like collagen chain that is related to the fibrillar alpha1(V), alpha1(XI), and alpha2(XI) collagen polypeptides and which is coexpressed with type I collagen in the developing bone and eye. The new collagen was designated the alpha1(XXIV) chain and consists of a long triple helical domain flanked by typical propeptide-like sequences. The carboxyl propeptide is classic, with 8 conserved cysteine residues. The amino-terminal peptide contains a thrombospodin-N-terminal-like (TSP) motif and a highly charged segment interspersed with several tyrosine residues, like the fibril diameter-regulating collagen chains alpha1(V) and alpha1(XI). However, a short imperfection in the triple helix makes alpha1(XXIV) unique from other chains of the vertebrate fibrillar collagen family. The triple helical interruption and additional select features in both terminal peptides are common to the fibrillar chains of invertebrate organisms. Based on these data, we propose that collagen XXIV is an ancient molecule that may contribute to the regulation of type I collagen fibrillogenesis at specific anatomical locations during fetal development.     

Phylogenetic position of turtles among amniotes: evidence from mitochondrial and nuclear genes

Maximum likelihood analysis, accounting for site-heterogeneity in evolutionary rate with the Gamma-distribution model, was carried out with amino acid sequences of 12 mitochondrial proteins and nucleotide sequences of mitochondrial 12S and 16S rRNAs from three turtles, one squamate, one crocodile, and eight birds. The analysis strongly suggests that turtles are closely related to archosaurs (birds+crocodilians), and it supports both Tree-2: (((birds, crocodilians), turtles), squamates) and Tree-3: ((birds, (crocodilians, turtles)), squamates). A more traditional Tree-1: (((birds, crocodilians), squamates), turtles) and a tree in which turtles are basal to other amniotes were rejected with high statistical significance. Tree-3 has recently been proposed by Hedges and Poling [Science 283 (1999) 998-1001] based mainly on nuclear genes. Therefore, we re-analyzed their data using the maximum likelihood method, and evaluated the total evidence of the analyses of mitochondrial and nuclear data sets. Tree-1 was again rejected strongly. The most likely hypothesis was Tree-3, though Tree-2 remained a plausible candidate.     

Tea polyphenols ameliorate fat storage induced by high-fat diet in Drosophila melanogaster

BackgroundPolyphenols in tea are considered beneficial to human health. However, many such claims of their bioactivity still require in vitro and in vivo evidence.ResultsUsing Drosophila melanogaster as a model multicellular organism, we assess the fat accumulation-suppressing effects of theaflavin (TF), a tea polyphenol; epitheaflagallin (ETG), which has an unknown function; and epigallocatechin gallate (EGCg), a prominent component of green tea. Dietary TF reduced the malondialdehyde accumulation related to a high-fat diet in adult flies. Other physiological and genetic responses induced by the high-fat diet, such as lipid accumulation in the fat body and expression of lipid metabolism-related genes, were ameliorated by the addition of TF, ETG, and EGCg, in some cases approaching respective levels without high-fat diet exposure. Continuous ingestion of the three polyphenols resulted in a shortened lifespan.ConclusionWe provide evidence in Drosophila that tea polyphenols have a fat accumulation-suppressing effect that has received recent attention. We also suggest that tea polyphenols can provide different desirable biological activities depending on their composition and the presence or absence of other chemical components.     

Geography-Dependent Horizontal Gene Transfer from Vertebrate Predators to Their Prey

Horizontal transfer (HT) of genes between multicellular animals, once thought to be extremely rare, is being more commonly detected, but its global geographic trend and transfer mechanism have not been investigated. We discovered a unique HT pattern of Bovine-B (BovB) LINE retrotransposons in vertebrates, with a bizarre transfer direction from predators (snakes) to their prey (frogs). At least 54 instances of BovB HT were detected, which we estimate to have occurred across time between 85 and 1.3 Ma. Using comprehensive transcontinental sampling, our study demonstrates that BovB HT is highly prevalent in one geographical region, Madagascar, suggesting important regional differences in the occurrence of HTs. We discovered parasite vectors that may plausibly transmit BovB and found that the proportion of BovB-positive parasites is also high in Madagascar where BovB thus might be physically transported by parasites to diverse vertebrates, potentially including humans. Remarkably, in two frog lineages, BovB HT occurred after migration from a non-HT area (Africa) to the HT hotspot (Madagascar). These results provide a novel perspective on how the prevalence of parasites influences the occurrence of HT in a region, similar to pathogens and their vectors in some endemic diseases.     

Simultaneous determination of catechols in thalamic slices with liquid chromatography/electrochemistry

A method was developed for the simultaneous determination of dopamine (DA), epinephrine (E), norepinephrine (NE), 3,4-dihydroxyphenylacetic acid (DOPAC) and 3-methoxy-4-hydroxyphenylglycol (MHPG), as well as L-3,4-dihydroxyphenylalanine (L-DOPA) with liquid chromatography (LC) using electrochemical (EC) detection. With a ODS column and a mobile phase consisting of a sodium acetate-citrate with heptasulfonic acid, this method was applied on simultaneous determination of catechols released from thalamic slices of ddY mouse. The pretreatment of the bathing medium required only centrifugation, and the supernatant was injected directly into the LCEC system. The high potassium stimulation of catecholaminergically innervated thalamic slices led to increase in the levels of DA, NE, DOPAC and MHPG, especially of NE, but not that of L-DOPA itself. In the present study, we designed to make simultaneous determination of catechols released from thalamic slices for estimation of the physiological status of catecholaminergic neuronal activity.     

Qualitative and Quantitative Analyses of the Echolocation Strategies of Bats on the Basis of Mathematical Modelling and Laboratory Experiments

Prey pursuit by an echolocating bat was studied theoretically and experimentally. First, a mathematical model was proposed to describe the flight dynamics of a bat and a single prey. In this model, the flight angle of the bat was affected by angles related to the flight path of the single moving prey, that is, the angle from the bat to the prey and the flight angle of the prey. Numerical simulation showed that the success rate of prey capture was high, when the bat mainly used the angle to the prey to minimize the distance to the prey, and also used the flight angle of the prey to minimize the difference in flight directions of itself and the prey. Second, parameters in the model were estimated according to experimental data obtained from video recordings taken while a Japanese horseshoe bat (Rhinolphus derrumequinum nippon) pursued a moving moth (Goniocraspidum pryeri) in a flight chamber. One of the estimated parameter values, which represents the ratio in the use of the angles, was consistent with the optimal value of the numerical simulation. This agreement between the numerical simulation and parameter estimation suggests that a bat chooses an effective flight path for successful prey capture by using the angles. Finally, the mathematical model was extended to include a bat and prey. Parameter estimation of the extended model based on laboratory experiments revealed the existence of bat’s dynamical attention towards prey, that is, simultaneous pursuit of prey and selective pursuit of respective prey. Thus, our mathematical model contributes not only to quantitative analysis of effective foraging, but also to qualitative evaluation of a bat’s dynamical flight strategy during multiple prey pursuit.     

Alternating Dependency of Cytokinin Activity on the Number of Methylene Units in ω-Phenylalkyl Derivatives of Some Purine Cytokinins and 4-Substituted Pyrido[3,4-d]pyrimidine

ω-Phenylalkyl derivatives of N⁶-substituted adenine, N⁶-substituted adenosine and 6-alkoxy-purine with odd numbers of methylenes had relatively high activity, while the corresponding 2-methyl-4-substituted-aminopyrido[3,4-d]pyrimidines with even numbers of methylenes had high activity in an Amaranthus betacyanin test and lettuce seed germination test. These results suggest that the ω-phenyl groups of the cytokinins play a specific role for cytokinin-receptor binding and that the pyrido[3,4-d]pyrimidines interact with a receptor in a different binding mode.