Zebrafish Dpr2 inhibits mesoderm induction by promoting degradation of nodal receptors

Nodal proteins, members of the transforming growth factor-beta (TGFbeta) superfamily, have been identified as key endogenous mesoderm inducers in vertebrates. Precise control of Nodal signaling is essential for normal development of embryos. Here, we report that zebrafish dapper2 (dpr2) is expressed in mesoderm precursors during early embryogenesis and is positively regulated by Nodal signals. In vivo functional studies in zebrafish suggest that Dpr2 suppresses mesoderm induction activities of Nodal signaling. Dpr2 is localized in late endosomes, binds to the TGFbeta receptors ALK5 and ALK4, and accelerates lysosomal degradation of these receptors.     

Treatment of an infrabony pocket in an American Eskimo dog

This case report describes the use synthetic bone graft particulate and 24% EDTA gel to treat an infrabony defect adjacent to the mandibular right first molar tooth in an American Eskimo dog. Postoperative examination 33-months following surgery showed osseous integration at the infrabony defect and restoration of the periodontal ligament space with a small refractory periodontal pocket.     

Effects of mushroom and herb polysaccharides, as alternatives for an antibiotic, on growth performance of broilers

(1) This in vivo trial was conducted to study the effects of polysaccharide extracts of two mushrooms, Lentinus edodes (LenE) and Tremella fuciformis (TreE), and a herb, Astragalus membranaceus (AstE) on growth performance, and the weights of organs and the gastrointestinal tract (GIT) of broiler chickens. (2) Three extracts (LenE, TreE and AstE) were supplemented at inclusion rates of 0.5, 1, 2, 3 and 4 g/kg from 7 to 14 d of age and compared with an antibiotic treatment group (20 mg/kg, virginiamycin (VRG) as well as a group of non-supplemented birds. (3) Body weight (BW) gain, feed intake and feed conversion ratio (FCR) of the extract-supplemented groups were not significantly different from those of the antibiotic group. Significant effects of type of extract and concentration on growth performance were found from 7 to 28 d of age. Generally, birds fed with LenE showed higher BW gain and lower FCR from 7 to 28 d of age than those fed with TreE and AstE and 2 g/kg LenE was considered the optimal inclusion rate for enhanced broiler growth. However, the extracts had no significant effect on the relative weights of organs and GIT compared with the antibiotic group. (4) The birds fed the extracts showed better growth performance than the non-supplemented birds, but were not significantly different from those fed VRG. Of the three extracts, LenE appeared to be a potential growth promoter. Future studies are needed to investigate whether the extracts can be used as alternatives for antibiotic growth promoters in challenged birds, and to elucidate the mechanisms for potentially enhanced growth performance in poultry.     

高效氯氰菊酯微乳剂液相色谱分析

本文介绍了从高效氯氰菊酯微乳剂中, 分离出有效成分高效氯氰菊酯, 再用正相液谱定量检测。该方法的变异系数为０．５１％ ,平均回收率为９９．９６％ 。     

Isotope-dilution technique for determination of endogenous faecal excretion and true absorption of iodine in 125I labelled rats

Introduction In studies on the quantitative mineral metabolism the separation of total faecal mineral excretion into the fraction of dietary and of endogenous origin is often a methodical barrier. Both components cannot be distinguished by standard chemical procedures. But their separation is essential to the quantification of the mineral flux from the diet into the organism and back from tissues into the faecal excretion as it is necessary for example to quantify the bioavailability of dietary mineral sources (K irchgessner et al. 1993). For this purpose, the use of isotopes is an appropriate means. During the last decades, several techniques employing radioactive or stable isotopes have been developed, e.g. the ‘comparative balance method’, the ‘dual tracer’ or ‘double isotope’ technique, methods based on computerized ‘compartment analysis’ and the ‘isotope-dilution technique’ (e.g. A ubert et al. 1963; T hompson 1965; B elshaw et al. 1974; G ibson et al. 1988). Among these methods, the isotope-dilution technique, in particular, comprises direct and quantitative measurements of mineral fluxes and provides robust estimates of endogenous faecal excretions as has been shown for a series of macrominerals and trace elements (W eigand and K irchgessner 1976a,b; W eigand et al. 1986a,b; K reuzer and K irchgessner 1991; R euber et al. 1993; K irchgessner et al. 1994; W indisch and K irchgessner 1994; W indisch et al. 1997; G abler et al. 1997). For iodine however, there is no appropriate isotope method available. Therefore, the present experiment was designed to establish the isotope-dilution technique for iodine. The isotope-dilution technique is based on a single parenteral injection or a long-term oral administration of the tracer (W indisch and K irchgessner 1994). After the labelling procedure, all tracer that appears in the faeces is of endogenous origin. The calculation from the quantity of tracer recovered in the faeces to the total amount of endogenous faecal excretion of the respective element is performed by the use of a reference tissue from which the endogenous excretion originates or which is at least in very close physiological relationship to the endogenous excretion. Using ¹²⁵I as tracer the total amount of endogenous faecal iodine is calculated as follows: Endogenous faecal iodine (ng/day) = A_faeces/SA_{reference tissue}A_faeces = ¹²⁵I activity in the faeces (Bq/day)SA_{reference tissue} = specific ¹²⁵I activity of the reference tissue (Bq ¹²⁵I per ng of total iodine)True absorption of dietary iodine (ng/day) = Iodine intake – iodine in faeces (total – endogenous)In total, the present methodological study had to focus on two major aspects. Since the administered tracer needs time to reach steady-state kinetics within the excretory pool of iodine it was to be clarified at first, from which day after a single ¹²⁵I administration does the faecal ¹²⁵I excretion correctly represent the total endogenous excretion quantitatively. Secondly, it had to be clarified which tissue or body fluid may be used as a proper reference source to quantify the endogenous faecal excretion and thus to calculate true absorption of iodine.