The inability of nuclear dehydrogenating clostridia to oxidize bile salt hydroxyl groups

Summary In a survey of the intracellular bile salt oxidoreductase activity in fecal bacteria, 16 strains of nuclear dehydrogenating clostridia and 2 strains of non-nuclear dehydrogenatingC. paraputrificum were demonstrated unable to oxidize cholate at any of the 3 OH groups. Since nuclear dehydrogenation at the -1 and -4 position requires a 3-oxo precursor steroid, it appears that these organisms require the presence of a 3-hydroxysteroid dehydrogenating organism for nuclear dehydrogenation.This work is supported by the National Cancer Institute of Canada (IAM) and by the Cancer Research Campaign (MJH).     

Interaction between delta-6-tetrahydrocannabinol (delta-6-THC) and lithium at the blood brain barrier in rats

Summary Neither the acute nor the chronic i.p. administration of delta-6-tetrahydrocannabinol affected the passage of lithium from blood to brain in normal rats.     

质子传导陶瓷膜在催化脱氢反应中的应用

有机化合物催化脱氢是一种吸热、体积增大的可逆反应过程,通过特定的膜将反应过程中生成的氢气不断地移出反应区,可促使反应向产物方向移动,从而提高反应转化率、减少副反应并最终达到降低反应温度、提高产率的目的。质子传导陶瓷膜可以以质子传递方式选择性透过氢,具有成本低、选择高,耐高温、热稳定及化学稳定性能好、不易中毒等特点,非常适合于脱氢膜反应器。本文对质子传导陶瓷膜材料、透氢机理、膜制备、膜反应器及其用于脱氢反应的研究现状与进展情况进行了综述。     

Nesprin interchain associations control nuclear size

Nesprins-1/-2/-3/-4 are nuclear envelope proteins, which connect nuclei to the cytoskeleton. The largest nesprin-1/-2 isoforms (termed giant) tether F-actin through their N-terminal actin binding domain (ABD). Nesprin-3, however, lacks an ABD and associates instead to plectin, which binds intermediate filaments. Nesprins are integrated into the outer nuclear membrane via their C-terminal KASH-domain. Here, we show that nesprin-1/-2 ABDs physically and functionally interact with nesprin-3. Thus, both ends of nesprin-1/-2 giant are integrated at the nuclear surface: via the C-terminal KASH-domain and the N-terminal ABD-nesprin-3 association. Interestingly, nesprin-2 ABD or KASH-domain overexpression leads to increased nuclear areas. Conversely, nesprin-2 mini (contains the ABD and KASH-domain but lacks the massive nesprin-2 giant rod segment) expression yields smaller nuclei. Nuclear shrinkage is further enhanced upon nesprin-3 co-expression or microfilament depolymerization. Our findings suggest that multivariate intermolecular nesprin interactions with the cytoskeleton form a lattice-like filamentous network covering the outer nuclear membrane, which determines nuclear size.     

Intranukleäre virusähnliche Partikeln in einem Mammakarzinom

Summary By electron microscopic examination of a solid, chiefly scirrhous mammary cancer, 3 kinds of unusual nuclear inclusions were found: (a) Electron dense particles of a 54–80 nm diameter, whose outlines appear mainly hexagonal, which points at an icosahedral structure, (b) Clusters of granules with a diameter of 200–300å, respectively 300–400å, at whose circumference the larger particles appear, (c) Bundles of filaments in close association and continuous with the granules. In all 3 nuclear inclusions there are subunits of 40–45å. The comparison between these results and experiments published suggest that these nuclear inclusions are (a) virus particles, (b) virus at an early stage of development and (c) virus protein subunits.     

Oxidation of bilirubin with chloranil. A simple method for preparing isomerically pure biliverdin

Summary Isomerically pure biliverdin IXa can be prepared in high yield through dehydrogenation of bilirubin IXa with chloranil-picric acid in chloroform containing t-butanol.     

Genetic determinants of individual differences in avoidance learning: Behavioral and endocrine characteristics

Bidirectional genetic selection for good and poor active avoidance learning in a shuttle box has been carried out in three independent laboratories using remarkably similar discrete-trial training procedures. The resulting strains are known as the Roman High and Low Avoidance (RHA and RLA), the Syracuse High and Low Avoidance (SHA and SLA) and the Australian High and Low Avoidance (AHA and ALA) strains, respectively. An additional unidirectionally selected strain, known as the Tokai High Avoider (THA) strain was developed in Japan using a free-operant Sidman avoidance procedure in a Skinner box. This paper reviews the selection of the Syracuse strains, enumerates the various behavioral and endocrine characteristics of the strains, and compares them to the other similarly selected strains. The behavioral work suggests that genetic selection from diverse breeding stocks has resulted in common characteristics that differentiate the strains in the emotional, not learning, domain. The endocrine data, however, are somewhat at odds. The Syracuse strains differentiate one way with respect to endocrine function, and the Roman strains differentiate in the opposite way. We suggest, therefore, that the endocrine correlates are not tightly linked to the avoidance genotype. Genetic analysis of all of the selected strains for both the avoidance phenotype and the endocrine correlates will be needed to test this hypothesis.Preparation of this paper was supported by research grant MH-39230-3 from the National Institute of Mental Health.     

Microtubule dynamics alter the interphase nucleus

Microtubules are known to drive chromosome movements and to induce nuclear envelope breakdown during mitosis and meiosis. Here we show that microtubules can enforce nuclear envelope folding and alter the levels of nuclear envelope-associated heterochromatin during interphase, when the nuclear envelope is intact. Microtubule reassembly, after chemically induced depolymerization led to folding of the nuclear envelope and to a transient accumulation of condensed chromatin at the site nearest the microtubule organizing center (MTOC). This microtubule-dependent chromatin accumulation next to the MTOC is dependent on the composition of the nuclear lamina and the activity of the dynein motor protein. We suggest that forces originating from simultaneous polymerization of microtubule fibers deform the nuclear membrane and the underlying lamina. Whereas dynein motor complexes localized to the nuclear envelope that slide along the microtubules transfer forces and/or signals into the nucleus to induce chromatin reorganization and accumulation at the nuclear membrane folds. Thus, our study identified a molecular mechanism by which mechanical forces generated in the cytoplasm reshape the nuclear envelope, alter the intranuclear organization of chromatin, and affect the architecture of the interphase nucleus.     

Dynamics of the nuclear envelope at mitosis and during apoptosis

The nuclear envelope is a highly dynamic structure that reversibly disassembles and reforms at mitosis. The nuclear envelope also breaks down--irreversibly--during apoptosis, a process essential for development and tissue homeostasis. Analyses of fixed cells, time-lapse, imaging studies of live cells and the development of powerful cell-free extracts derived from gametes or mammalian somatic cells have provided insights on the fate of nuclear envelope proteins during mitosis and apoptosis, and on the mechanisms behind nuclear envelope modifications in these processes. In this review, we discuss evidence leading to our understanding of the dynamics of the nuclear envelope alterations at mitosis and during apoptosis. We also present novel imaging and genetic approaches to the study of nuclear envelope dynamics and function.     

Endogenous gibberellins and amylase activity in tall and dwarf strains of rice (Oryza sativa)

Summary 2 tall and 7 dwarf strains of rice were sprayed with 0 or 40 g ml^–1 GA₃, 4 dwarf strains responded to exogenous GA₃, and showed a markedly lower endogenous gibberellin content than the tall strains, while 2 dwarf strains did not respond to GA₃ application and had considerably higher endogenous gibberellin levels than the tall ones. Amylase activity in germinating seeds showed a significant negative correlation with the endogenous gibberellin content.     

Frequency and distribution of tubulo-filamentous nuclear inclusions in the celiac ganglion of the cat as revealed by serial sections.

On sections at random of a cat celiac ganglion we counted 68 sections of nuclear inclusions (NI) for 320 sections of neuronal nuclei, i.e. an "apparent' frequency of 0.20. As revealed by serial sections the "actual' frequency is higher since the 5 nuclei entirely explored exhibit 19 NI. Such a study shows that each nucleus may contain at least 3 and up to 5 different tubulo-filamentous NI.     

L'activité leucémogène des rayons X chez la Souris de la lignée Suisse

Summary Mice of the Swiss stock, a pure strain, irradiated at the age of 3 to 4 months, were found to be very sensitive to the induction of lymphoid radioleukemia, particularly thymic; this fact contrasts with the observations made in other strains of mice.     

Über den Mechanismus der Osazonreaktion

Summary For the osazone reaction of the reducing sugars, the following mechanism is suggested: the initially formed phenylhydrazone is converted with aniline into the N-glycoside. Aniline arises from disproportional decomposition of phenylhydrazine. The N-glycoside undergoes an Amadori-rearrangement to 1-deoxy-1-amino-2-ketose derivative. From this is formed the phenylhydrazone. The latter is converted by dehydrogenation and transamination into the phenylosazone.     

Cytostatischer Wirkungsmechanismus der Methylhydrazine

Summary Cytostatic active methylhydrazine derivatives split off formaldehyde after mild dehydrogenation with potassium hexacyanoferrate (III). It is suggested that the primary formedazomethines andN-hydroxymethylderivatives participate in cytostatic efficacy by their alkylating ability (aminomethylation). Formaldehyde alone and its condensation products with hydrogen peroxide especially bis-hydroxymethylperoxide may exert cytostatic effects too.     

Long-term changes in tyrosine phosphorylation of the abundant nuclear proteins during granulocytic differentiation of HL-60 cells

The two-dimensional electrophoretic patterns of nuclear proteins and their tyrosine phosphorylation were compared for HL-60 cells before and after differentiation induction to granulocytes by dimethyl sulfoxide, all-trans retinoic acid and N ⁶,O ²-dibutyryl adenosine 3′5′-cyclic monophosphate. Regardless of the inducer used, some nuclear proteins, which are tyrosine-phosphorylated in proliferating HL-60 cells, undergo gradual dephosphorylation 12–72 h after induction of differentiation, followed by drastic dephosphorylation during maturation to granulocytes. At least 13 nuclear proteins with a molecular mass of 35–110 kDa are dephosphorylated, and 6 nuclear proteins undergo tyrosine phosphorylation. Analysis of the nuclear proteins differentially extracted by salt and detergents indicates that changes in their tyrosine phosphorylation during the maturation stage of differentiating granulocytes occur mainly in proteins which are abundant in nucleoplasm, chromatin and residual nuclear structures. The abundance of these proteins, residing in the nuclear structures, and their long-term modification in phosphorylation during the maturation stages of differentiation strongly suggest that tyrosine phosphorylation of these proteins is involved in reorganization of the differentiating cell nucleus. Received 21 September 1998; received after revision 24 November 1998; accepted 3 December 1998