The regulation and function of the helix-loop-helix gene, asense, in Drosophila neural precursors

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 19-29 ◽  
Author(s):  
A.P. Jarman ◽  
M. Brand ◽  
L.Y. Jan ◽  
Y.N. Jan
Keyword(s):  
Expression Pattern ◽  
Fusion Gene ◽  
Regulatory Element ◽  
The Other ◽  
Neural Precursor ◽  
Neural Precursors ◽  
Helix Loop Helix ◽  
Significant Expression ◽  
And Function

asense is a member of the achaete-scute complex (AS-C) of helix-loop-helix genes involved in Drosophila neurogenesis. Unlike the other AS-C members, which are expressed in subsets of the ectodermal areas (proneural clusters) that give rise to neural precursors, asense is one of a number of genes that are specifically expressed in the neural precursors themselves (neural precursor genes). We have identified a mutant asense phenotype that may reflect this later expression pattern. As a step in understanding the determination of neural precursors from the proneural clusters, we have investigated the potential role of the AS-C products as direct transcriptional activators of neural precursor genes by analysing the regulation of asense. Using genomic rescues and asense-lacZ fusion genes, the neural precursor regulatory element has been identified. We show that this element contains binding sites for AS-C/daughterless heterodimers. Delection of these sites reduces the expression from the fusion gene, but significant expression is still achieved, pointing to the existence of other regulators of asense in addition to the AS-C. asense differs from the other AS-C members in its expression pattern, regulation, mutant phenotype and some DNA-binding properities.

The development and function of the rumen in milk-fed calves

1959 ◽  
Vol 52 (1) ◽  
pp. 72-78 ◽  
Author(s):  
R. H. Smith
Keyword(s):  
Body Weight ◽  
Polyethylene Glycol ◽  
Small Extent ◽  
The Other ◽  
Subsequent Determination ◽  
Different Ages ◽  
Unit Body Weight ◽  
The One ◽  
And Function

1. The volume of rumen liquor in milk-fed calves at different ages up to 32 weeks was estimated by injecting polyethylene glycol into the rumen and subsequently determining its concentration in the rumen liquor. This volume increased progressively with age in relation to unit body weight. The increase xswas approximately fourfold between 4–8 weeks on the one hand and 28–32 weeks on the other.2. The amount of milk entering the rumen during a feed was estimated at different ages up to 32 weeks by the subsequent determination of the volume and fat content of the rumen liquor. In the majority of cases less than 5% of the milk fed entered the rumen. There did not appear to be any increase in the quantities of milk entering the rumen as the calves got older.3. An estimate of the rate of flow of fluid into and out of the rumen (other than milk at feeding) was made by measuring the rate of disappearance of polyethylene glycol from the rumen. A mean figure of 255 ml./hr./100 kg. body weight s.d. ± 50 was obtained in this way. It is suggested that this value probably represents the rate of flow of saliva.4. Magnesium, in a concentration up to about 8 mg./100 ml. in the rumen liquor, did not appear to be absorbed to more than a small extent through the rumen wall.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

Determination of the Burgers vector of a dislocation in a Fe-Mn alloy by weak-beam image in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 330-331
Author(s):  
Y. Ishida ◽  
H. Ishida ◽  
K. Kohra ◽  
H. Ichinose
Keyword(s):  
High Order ◽  
Simulation Technique ◽  
The Other ◽  
Image Simulation ◽  
Diffraction Vector ◽  
Burgers Vector ◽  
Weak Beam ◽  
Beam Image ◽  
Edge Component

IntroductionA simple and accurate technique to determine the Burgers vector of a dislocation has become feasible with the advent of HVEM. The conventional image vanishing technique(1) using Bragg conditions with the diffraction vector perpendicular to the Burgers vector suffers from various drawbacks; The dislocation image appears even when the g.b = 0 criterion is satisfied, if the edge component of the dislocation is large. On the other hand, the image disappears for certain high order diffractions even when g.b ≠ 0. Furthermore, the determination of the magnitude of the Burgers vector is not easy with the criterion. Recent image simulation technique is free from the ambiguities but require too many parameters for the computation. The weak-beam “fringe counting” technique investigated in the present study is immune from the problems. Even the magnitude of the Burgers vector is determined from the number of the terminating thickness fringes at the exit of the dislocation in wedge shaped foil surfaces.

Platelet Suruival and Function in Rats with Enhanced Thrombotic Tendency

1985 ◽  
Vol 54 (04) ◽  
pp. 739-743 ◽  
Author(s):  
Federica Delaini ◽  
Elisabetta Dejana ◽  
Ine Reyers ◽  
Elisa Vicenzi ◽  
Germana De Bellis Vitti ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Nephrotic Syndrome ◽  
Platelet Function ◽  
Laboratory Tests ◽  
Thrombus Formation ◽  
The Other ◽  
Mean Survival Time ◽  
The Mean ◽  
And Function ◽  
Thrombotic Tendency

SummaryWe have investigated the relevance of some laboratory tests of platelet function in predicting conditions of thrombotic tendency. For this purpose, we studied platelet survival, platelet aggregation in response to different stimuli, TxB2 and 6-keto-PGFlα production in serum of rats bearing a nephrotic syndrome induced by adriamycin. These animals show a heavy predisposition to the development of both arterial and venous thrombosis. The mean survival time was normal in nephrotic rats in comparison to controls. As to aggregation tests, a lower aggregating response was found in ADR-treated rats using ADP or collagen as stimulating agents. With arachidonic acid (AA) we observed similar aggregating responses at lower A A concentrations, whereas at higher AA concentrations a significantly lower response was found in nephrotic rats, despite their higher TxB2 production. Also TxB2 and 6-keto-PGFlα levels in serum of nephrotic rats were significantly higher than in controls. No consistent differences were found in PGI2-activity generated by vessels of control or nephrotic rats.These data show that platelet function may appear normal or even impaired in rats with a markedly increased thrombotic tendency. On the other hand, the significance of high TxB2 levels in connection with mechanisms leading to thrombus formation remains a controversial issue.

Procedures for the Quantitative Determination of Autoprothrombin C

1962 ◽  
Vol 08 (03) ◽  
pp. 434-441 ◽  
Author(s):  
Edmond R Cole ◽  
Ewa Marciniak ◽  
Walter H Seegers
Keyword(s):  
Quantitative Determination ◽  
Plasma Sample ◽  
Quantitative Measure ◽  
The Other ◽  
Clotting Time ◽  
Bovine Plasma ◽  
Autoprothrombin C

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.

Determination of Factor XIII Activity and of Factor XIII Inhibitors Using an Ammonium-Sensitive Electrode

1983 ◽  
Vol 50 (02) ◽  
pp. 563-566 ◽  
Author(s):  
P Hellstern ◽  
K Schilz ◽  
G von Blohn ◽  
E Wenzel
Keyword(s):  
Factor Xiii ◽  
Normal Subjects ◽  
The Other ◽  
Activity Measurement ◽  
Factor Xiii Deficiency ◽  
Assay Procedure ◽  
Stabilization Factor ◽  
Release Method ◽  
Sensitive Electrode

SummaryAn assay for rapid factor XIII activity measurement has been developed based on the determination of the ammonium released during fibrin stabilization. Factor XIII was activated by thrombin and calcium. Ammonium was measured by an ammonium-sensitive electrode. It was demonstrated that the assay procedure yields accurate and precise results and that factor XIII-catalyzed fibrin stabilization can be measured kinetically. The amount of ammonium released during the first 90 min of fibrin stabilization was found to be 7.8 ± 0.5 moles per mole fibrinogen, which is in agreement with the findings of other authors. In 15 normal subjects and in 15 patients suffering from diseases with suspected factor XIII deficiency there was a satisfactory correlation between the results obtained by the “ammonium-release-method”, Bohn’s method, and the immunological assay (r1 = 0.65; r2= 0.70; p<0.01). In 3 of 5 patients with paraproteinemias the values of factor XIII activity determined by the ammonium-release method were markedly lower than those estimated by the other methods. It could be shown that inhibitor mechanisms were responsible for these discrepancies.

scholarly journals Relationship between the Geotourism Potential and Function in the Polish Part of the Roztocze Transboundary Biosphere Reserve

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 120
Author(s):  
Teresa Brzezińska-Wójcik
Keyword(s):  
Sustainable Development ◽  
Biosphere Reserve ◽  
The Other ◽  
Partial Indices ◽  
Function Index ◽  
Intensive Exploitation ◽  
Potential Indicator ◽  
Current Product ◽  
And Function ◽  
Further Development

The Polish part of the Roztocze Transboundary Biosphere Reserve area is characterized by diversified geotourism resources with relatively high value. However, their potential seems not to be fully used in the current product offer. The aim of the study was therefore to assess the spatial variability of the geotourism potential and function and to determine their interrelations in view of further development of geotourism in the Roztocze TBR and the perspective of creation of the “Kamienny Las na Roztoczu” geopark. The study was carried out with the use of the taxonomic method of multidimensional comparative analysis consisting of calculation and analysis of general, total, and partial indices of the geotourism potential and function in 22 communes. The results showed the highest total indicator of geotourism potential in two communes, i.e. Józefów and Krasnobród, and the highest value of the total geotourism function index in Krasnobród. The results of the analysis of the relationships between the geotourism potential and function indicate that the geotourism resources and products are fully used in terms of the development of the function only in Krasnobród commune. In turn, the value of the total geotourism function index in the Zwierzyniec commune exceeds the geotourism potential indicator, which implies that this area is overloaded by tourist movement. The total indicators of geotourism potential in the other communes, especially Józefów, Krasnobród, Lubycza Królewska, and Susiec, indicate the possibility of more intensive exploitation of geotourism resources in preparation of interesting products in compliance with the principles of sustainable development and, consequently, the development of the geotourism function.

scholarly journals The Drosophila engrailed and invected Genes: Partners in Regulation, Expression and Function

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 893-906 ◽  
Author(s):  
Elizabeth Gustavson ◽  
Andrew S Goldsborough ◽  
Zehra Ali ◽  
Thomas B Kornberg
Keyword(s):  
Expression Pattern ◽  
Cultured Cells ◽  
Regulatory Region ◽  
Embryonic Lethality ◽  
Wild Type ◽  
Terminal Portion ◽  
Coding Sequence ◽  
Differential Effects ◽  
And Function ◽  
Redundant Functions

Abstract We isolated and characterized numerous engrailed and invected alleles. Among the deficiencies we isolated, a mutant lacking invected sequences was viable and phenotypically normal, a mutant lacking engrailed was an embryo lethal and had slight segmentation defects, and a mutant lacking both engrailed and invected was most severely affected. In seven engrailed alleles, mutations caused translation to terminate prematurely in the central or C-terminal portion of the coding sequence, resulting in embryonic lethality and segmentation defects. Both engrailed and invected expression declined prematurely in these mutant embryos. In wild-type embryos, engrailed and invected are juxtaposed and are expressed in essentially identical patterns. A breakpoint mutant that separates the mgrailed and invected transcription units parceled different aspects of the expression pattern to engrailed or invected. We also found that both genes cause similar defects when expressed ectopically and that the protein products of both genes act to repress transcription in cultured cells. We propose that the varied phenotypes of the engrailed alleles can be explained by the differential effects these mutants have on the combination of engrailed and invected activities, that engrailed and invected share a regulatory region, and that they encode redundant functions.

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