Exploitative competition between two seed parasites on the common sedge, Carex nigra

We present results from a two-year experiment studying the competitive interaction between the gall mite Phytoptus caricis and the smut fungus Anthracoidea heterospora . A factorial addition/removal experiment showed that a negative interaction occurs between A. heterospora and P. caricis , presumably due to competitive interactions in the early infection process of their shared resource, developing utricles on the common sedge, C. nigra . Strong effects of interspecific competition for both species were only evident in 1995 while A. heterospora showed some signs of suffering negative effects from competition also in 1994. Results thus suggest that significant effects of competitive interaction may only be apparent when densities of the two competitors are fairly high. The interaction was strongly asymmetric, with A. heterospora being more affected by the presence of P. caricis than vice versa. Estimates of interaction strength for A. heterospora were about twice as large compared to that for P. caricis . The difference in interaction was significant when data were pooled over the two years of the study. The study highlights the need to consider interspecific interactions between different plant parasites when studying the effects of plant pathogens.     

The Synthesis and Antiherpetic Activity of DHBG and Some Analogs

Abstract

Several acyclic guanosine analogs have been synthesized and tested for antiviral activity.     

Use of chlorite to improve HPLC detection of pyridoxal 5'-phosphate

The sensitivity of fluorescent detection of the biologically active form of Vitamin B-6, pyridoxal 5'-phosphate (PLP), in biological samples has been improved approximately four-fold by adopting chlorite as a post-column derivatization reagent (instead of bisulfite) in high-performance liquid chromatography (HPLC) separation. Chlorite oxidizes PLP to the more fluorescent 4-pyridoxic acid 5'-phosphate, and avoids the toxicity and heating of the cyanide procedure. Detection of another major metabolite, 4-pyridoxic acid (4-PA), is not effected. Detection of pyridoxal (PL) is slightly lowered due to eluting at a lower pH.     

Vanadate stimulates monocytic differentiation activity of IL-6 by enhancing actin filament polymerization in HL-60 cells

IL-6 is involved in the control of differentiation of the acute promyelocytic leukemia cell line, HL-60. However, the participation of protein tyrosine phosphatase (PTP) in the monocytic differentiation activity of IL-6 at low concentrations has not been well clarified. In the present study, we demonstrate that IL-6 (10 ng/ml) alone increased cell growth without differentiation. In the presence of vanadate (10 µM), a PTP inhibitor, IL-6 induced pronounced G0/G1 cell cycle arrest; this effect was associated with CD14+ monocytic differentiation as well as F-actin filament polymerization. Furthermore, vanadate potentiated IL-6-signaling pathway by increasing the tyrosine phosphorylated levels of STAT3 (Tyr705), and Lyn. Such induction of Lyn kinase activity resulted from hypophosphorylated tyrosine (Tyr507) at its negative regulatory site. Vanadate also cooperated with IL-6 to form a protein complex containing Lyn and an actinassociated protein, AFAP110. A complex between Lyn and AFAP110 may serve to regulate F-actin filament polymerization. In conclusion, inhibition of PTP by vanadate promotes hematopoietic differentiation activity of IL-6 through modulating multiple signalings, particularly actin filament polymerization.     

Potent nonpeptide vasopressin receptor antagonists based on oxazino- and thiazinobenzodiazepine templates

Vasopressin receptor antagonists can elicit ion-sparing diuretic effects (i.e., aquaresis) in vivo by blunting the action of the circulating hypophyseal hormone arginine vasopressin. We have identified two new series of basic tricyclic benzodiazepines, represented by general structure 1, which contain compounds that bind with high affinity to human V2 receptors. For example, (S)-(+)-8 and 5 are potent and selective V2 receptor antagonists with pronounced aquaretic activity in rats on oral administration.     

The spatio-temporal colonization and diversification across the Indo-Pacific by a ‘great speciator’ (Aves,Erythropitta erythrogaster)

The Indo-Pacific region has arguably been the most important area for the formulation of theories about biogeography and speciation, but modern studies of the tempo, mode and magnitude of diversification across this region are scarce. We study the biogeographic history and characterize levels of diversification in the wide-ranging passerine bird Erythropitta erythrogaster using molecular, phylogeographic and population genetics methods, as well as morphometric and plumage analyses. Our results suggest that E. erythrogaster colonized the Indo-Pacific during the Pleistocene in an eastward direction following a stepping stone pathway, and that sea-level fluctuations during the Pleistocene may have promoted gene flow only locally. A molecular species delimitation test suggests that several allopatric island populations of E. erythrogaster may be regarded as species. Most of these putative new species are further characterized by diagnostic differences in plumage. Our study reconfirms the E. erythrogaster complex as a ‘great speciator’: it represents a complex of up to 17 allopatrically distributed, reciprocally monophyletic and/or morphologically diagnosable species that originated during the Pleistocene. Our results support the view that observed latitudinal gradients of genetic divergence among avian sister species may have been affected by incomplete knowledge of taxonomic limits in tropical bird species.     

赖氨酰氧化酶与人类疾病

赖氨酰氧化酶(lysyl oxidases,LOXs)是一种能够催化细胞外基质蛋白(如胶原和弹性蛋白)交叉连接的酶类,这一功能使其在组织的稳定、重塑和伤口愈合中发挥重要作用.随着研究的不断深入,LOXs在细胞增殖、细胞趋化以及肿瘤发生等过程中也彰显出十分关键的作用.研究发现,一些诸如结缔组织病、剥脱综合症、铜代谢障碍性疾病及盆腔器官脱垂和骨疾等疾病的发生与LOXs有很大关系.综述了LOXs的生物合成、结构特点、多功能性以及与人类疾病的关系.     

Fusion of radiostereometric analysis data into computed tomography space: application to the elbow joint

Improvement of joint prostheses is dependent upon information concerning the biomechanical properties of the joint. Radiostereometric analysis (RSA) and electromagnetic techniques have been applied in previous cadaver and in vivo studies on the elbow joint to provide valuable information concerning joint motion axes. However, such information is limited to mathematically calculated positions of the axes according to an orthogonal coordinate system and is difficult to relate to individual skeletal anatomy. The aim of this study was to evaluate the in vivo application of a new fusion method to provide three-dimensional (3D) visualization of flexion axes according to bony landmarks. In vivo RSA data of the elbow joint's flexion axes was combined with data obtained by 3D computed tomography (CT). Results were obtained from five healthy subjects after one was excluded due to an instable RSA marker. The median error between imported and transformed RSA marker coordinates and those obtained in the CT volume was 0.22 mm. Median maximal rotation error after transformation of the rigid RSA body to the CT volume was 0.003 degrees . Points of interception with a plane calculated in the RSA orthogonal coordinate system were imported into the CT volume, facilitating the 3D visualization of the flexion axes. This study demonstrates a successful fusion of RSA and CT data, without significant loss of RSA accuracy. The method could be used for relating individual motion axes to a 3D representation of relevant joint anatomy, thus providing important information for clinical applications such as the development of joint prostheses.     

An Innovative Method for Obtaining Consistent Images and Quantification of Histochemically Stained Specimens

Obtaining digital images of color brightfield microscopy is an important aspect of biomedical research and the clinical practice of diagnostic pathology. Although the field of digital pathology has had tremendous advances in whole-slide imaging systems, little effort has been directed toward standardizing color brightfield digital imaging to maintain image-to-image consistency and tonal linearity. Using a single camera and microscope to obtain digital images of three stains, we show that microscope and camera systems inherently produce image-to-image variation. Moreover, we demonstrate that post-processing with a widely used raster graphics editor software program does not completely correct for session-to-session inconsistency. We introduce a reliable method for creating consistent images with a hardware/software solution (ChromaCal™; Datacolor Inc., NJ) along with its features for creating color standardization, preserving linear tonal levels, providing automated white balancing and setting automated brightness to consistent levels. The resulting image consistency using this method will also streamline mean density and morphometry measurements, as images are easily segmented and single thresholds can be used. We suggest that this is a superior method for color brightfield imaging, which can be used for quantification and can be readily incorporated into workflows.