The Boring Cunctichnus probans Fürsich,Palmer and Goodyear, 1994, from the Type Maastrichtian (Upper Cretaceous,Northeast Belgium)

The ichnogenus Cunctichnus Fürsich, Palmer and Goodyear, 1994 is monotypic, its type ichnospecies, C. probans Fürsich, Palmer and Goodyear, 1994, having hitherto been described solely from the Upper Jurassic (Tithonian) of southern England and the Paris Basin. Cunctichnus probans is recorded herein from the type Maastrichtian (Upper Cretaceous) of the province of Liège, northeast Belgium, that is, about 75 million years younger than previous published records. This specimen differs from the holotype in having a Y-shaped branch.     

Quadrat covariance analysis and the scales of interspecific association during primary succession

Abstract. Three term covariance analysis is used to investigate interspecific association at a range of spatial scales, using both density and presence/absence data to evaluate the strength of species interactions. This procedure also investigates the relationship between the spatial patterns of species. These methods are applied to the vegetation on a series of glacial moraines near Mt. Robson, British Columbia, Canada, in order to test whether the plants of different species and their patterns become more independent and more random during succession. Another hypothesis tested is that if a species exerts a positive influence on others by increasing soil nutrients, this effect decreases with surface age. The vegetation analysed supports both these hypotheses to the extent that most species pairs have maximum covariance intensity on medium aged surfaces. The covariance-blocksize graphs derived from density data and from presence/absence data were qualitatively similar in their trends; however, the results are sufficiently different to suggest that the relationships among species can be subtle, affecting density rather than presence. The results also show that the affect of scale on species associations is more complex than simple models predict.     

When the tail can't wag the dog: the implications of CNS-intrinsic initiation of neuroinflammation

The CNS (central nervous system) is unquestionably the central organ that regulates directly or indirectly all physiological systems in the mammalian body. Yet, when considering the defence of the CNS from pathogens, the CNS has often been considered passive and subservient to the pro-inflammatory responses of the immune system. In this view, neuroinflammatory disorders are examples of when the tail (the immune system) wags the dog (the CNS) to the detriment of an individual''s function and survival.     

Early ontogeny of Adinia xenica (Pisces,Cyprinodontiformes): 2. Implications of embryonic resting interval for larval development

Synopsis Larval development commences with first exogenous feeding, and ends with final remodelling of caenogenetic structures into the definitive organs of juvenile and adult. For the intertidal cyprinodontid Adinia xenica this generally corresponds to the interval between hatching and completion of scalation. The final step of the embryo period is a resting interval of variable duration. Embryos were induced to hatch after 2 and 10 days of this near arrest. Although the general pattern of larval development was the same for both groups, differences were observed in the rates and order of calcification of skeletal elements, fin differentiation and growth, and scalation. For example, embryos hatching 8 days later in the resting interval were already pattially calcified, but completed calcification at a slower rate than the group hatching after 2 days. These differences may be due to effects of the duration of the resting interval itself; or they may reflect genetic variation of which age at hatching is only one manifestation.     

图形视网膜电图的空间和时间调谐特性——FFT分析

用快速傅里叶转换(FFT)技术分析了图形视网膜电图(PERG)的空间和时间调谐特性。PERG 的二次谐波在较高的空间频率(>0.46周/度)逐渐下降,与 PERG振幅的变化相似,但显示明显的低空间频率衰减。空间和时间调谐特性存在一定的相关。引起最大二次谐波振幅的最佳时间频率,在低空间频率时(<0.23周/度)由低频(≤3.91Hz)移至 7.81Hz。     

Effects of Dichloroisoproterenol on Macromolecular Synthesis and Differentiation in Tetrahymena vorax

ABSTRACT. The effect of dichloroisoproterenol on macrostomal cell formation in Tetrahymena vorax was examined and the drug was found to be 50% inhibitory at a concentration of 88 μM. Cellular uptake and incorporation of a variety of radiolabelled precursors was monitored in the presence of dichloroisoproterenol. The results demonstrate a strong, concentration-dependent inhibitory effect on RNA and protein biosynthesis, with a lesser inhibition observed for lipid biosynthesis. These data indicate that dichloroisoproterenol's reported effects on vacuole formation and processing in Tetrahymena are nonspecific with regard to phagocytic processes, but result from a general suppression of macromolecular synthesis.     

Heterodimerization is mainly responsible for the dominant negative activity of amino-terminally truncated rat androgen receptor forms

Rat androgen receptor (rAR) mutants devoid of the amino-terminal transactivation domain are able to behave as dominant negative regulators of wild-type rAR. To address the underlying mechanisms of the trans-dominant negative action, we have examined the roles of the DNA-binding domain (DBD) and the ligand-binding domain (LBD) in this process. Transactivation experiments in CV-1 cells complemented by electrophoretic mobility shift assays revealed that the dominant negative receptor forms repress the function of wild-type rAR mainly through heterodimer formation, rather than through competition for binding to cognate DNA elements. Heterodimerization of receptor forms containing LBDs may take place even in the absence of specific DNA binding.     

The Influence of the Non‐Nucleotide Insert on the Hybridization Properties of Oligonucleotides

The effect of different non‐nucleotide inserts incorporated into oligonucleotide chains on their hybridization properties was studied by the method of thermal denaturation. Various types of alkyldiols and oligoethylene glycols were used as inserts modifying oligonucleotide backbone. Such modification of oligonucleotides caused the destabilization of their complementary complexes. It was shown that the hybridization properties of the modified oligonucleotides depend on several features of inserts: the type, number, length of insertions, and positions of interrupted dinucleotide steps in oligonucleotide chain.