A Stable Genomic Source of P Element Transposase in Drosophila Melanogaster

A single P element insert in Drosophila melanogaster, called P[ry+ delta 2-3](99B), is described that caused mobilization of other elements at unusually high frequencies, yet is itself remarkably stable. Its transposase activity is higher than that of an entire P strain, but it rarely undergoes internal deletion, excision or transposition. This element was constructed by F. Laski, D. Rio and G. Rubin for other purposes, but we have found it to be useful for experiments involving P elements. We demonstrate that together with a chromosome bearing numerous nonautonomous elements it can be used for P element mutagenesis. It can also substitute efficiently for "helper" plasmids in P element mediated transformation, and can be used to move transformed elements around the genome.     

Effects of an inhibitor of adenosine deaminase,deoxycoformycin, and of nucleoside transport,propentofylline, on post-ischemic recovery of adenine nucleotides in rat brain

The effects of an adenosine deaminase inhibitor (deoxycoformycin, 500 μg/kg) and of an inhibitor of nucleoside transport (propentofylline, 10 mg/kg) on adenosine and adenine nucleotide levels in the ischemic rat brain were investigated. The brains of the rats were microwaved before, at the end of a 20 min period of cerebral ischemia (4 vessel occlusion+hypotension), or after 5, 10, 45, and 90 min of reperfusion. Deoxycoformycin increased brain adenosine levels during both ischemia and the initial phases of reperfusion. AMP levels were elevated during ischemia and after 5 min of reperfusion. ATP levels were elevated above those in the non-treated animals after 10 and 45 min of reperfusion. ADP levels were elevated above the non-drug controls at 90 min. These increases in ATP, ADP and AMP resulted in significant increases in total adenylates during ischemia, and after 10 min and 90 min of reperfusion. Propentofylline administration resulted in enhanced AMP levels during ischemia but did not alter adenosine or adenine nucleotide levels during reperfusion in comparison with non-treated controls.     

Dye–tissue interactions: mechanisms,quantification and bonding parameters for dyes used in biological staining

Staining of tissues by dyes is accomplished through various types of bonds, some of which have been poorly defined in traditional biological literature. Here, basic principles of bonding are reviewed to establish uniform terminology and definitions consistent with the field of chemistry. The concept of charge – its presence or absence, magnitude, extent of delocalization and potential for being displaced by outside forces – underlies all bonding phenomena. These same attributes influence solubility and resistance to extraction during dehydration of tissue sections. Covalent bonds involve shared electrons; they are very strong and essentially irreversible under conditions encountered during staining. Polar covalent bonds within dye molecules generate partial atomic charges that create the potential for hydrogen bonding. This is measured by the hydrogen bonding parameter (h), the number of groups bearing charges within the ranges ?0.15 to ?0.50 eV or +0.15 to +0.30 eV. The potential for ionic bonding is indicated by net charge (Z), while the strength of such bonds is a function of charge site geometry on both bonding partners. Charge delocalization owing to conjugation, electron influencing groups, and resonance creates soft charge sites in which the ionic charge is spread over a large volume. Poorly delocalized charges or point charges are hard (small in volume). Firm bonds result from hard-hard or soft-soft pairs. Hard-soft combinations are weak, readily displaced in competitive interactions, and disrupted by solvents. Coordinate bonds with certain metals are involved with mordant staining and metal chelation dyes. Three different van der Waals attractions comprise the remainder of bonding types, all involving dipoles: Keesom (dipole-dipole) forces, Debye (dipole-induced dipole) forces and London (induced dipole-induced dipole) forces. Potentials for engaging in any of these is quantified by measures of polarity (dipole moment, d), polarizability (crudely with π atoms describing the size of the conjugated system, or more directly with α), hydrophobicity (with the octanol-water partition coefficient, log P or the more convenient Hydrophobic Index, HI), and the number of halogen atoms (X). By using molecular modeling software, quantitative measures of bonding potential (bonding parameters) have been determined for over 400 dyes.     

Intersection tests for single marker QTL analysis can be more powerful than two marker QTL analysis

Background

It has been reported in the quantitative trait locus (QTL) literature that when testing for QTL location and effect, the statistical power supporting methodologies based on two markers and their estimated genetic map is higher than for the genetic map independent methodologies known as single marker analyses. Close examination of these reports reveals that the two marker approaches are more powerful than single marker analyses only in certain cases.Simulation studies are a commonly used tool to determine the behavior of test statistics under known conditions. We conducted a simulation study to assess the general behavior of an intersection test and a two marker test under a variety of conditions. The study was designed to reveal whether two marker tests are always more powerful than intersection tests, or whether there are cases when an intersection test may outperform the two marker approach.We present a reanalysis of a data set from a QTL study of ovariole number in Drosophila melanogaster.

Results

Our simulation study results show that there are situations where the single marker intersection test equals or outperforms the two marker test. The intersection test and the two marker test identify overlapping regions in the reanalysis of the Drosophila melanogaster data. The region identified is consistent with a regression based interval mapping analysis.

Conclusion

We find that the intersection test is appropriate for analysis of QTL data. This approach has the advantage of simplicity and for certain situations supplies equivalent or more powerful results than a comparable two marker test.

     

Actions of various gastrointestinal peptides on the isolated amphibian spinal cord.

The effects of a number of peptides which are found in the gastrointestinal tract have been ascertained on the direct current recorded dorsal and ventral root responses of the isolated hemisected toad spinal cord. Motilin, substance P, bombesin, neurotensin, and thyrotropin releasing hormone had potent depolarizing actions on dorsal root terminals and motoneurons. These substances evoked discernable effects at concentrations as low as 10--7 M, or even lower with motilin. The effects of motilin, neurotensin, and thyrotropin-releasing hormone were greatly reduced or abolished by perfusion of the preparation with tetrodotoxin. Adrenocorticotrophic hormone, secretin, and pancreozymin (cholecystokinin) also depolarized dorsal root terminals and motoneurons. The effects of secretin and cholecystokinin were not abolished by tetrodotoxin. Leu- and Met-enkephalin had weak hyperpolarizing actions on the dorsal and ventral root potentials of repetitively stimulated preparations. Gastrin, gastric inhibitory peptide, glucagon, and somatostatin had no apparent effects on the responses of the preparation. Angiotensin and vasopressin both had rather weak depolarizing effects on the dorsal and ventral roots.     

Adenosine receptors in rat brain membranes: characterization of high affinity binding of [3H]-2-chloroadenosine

1. [3H]-2-chloroadenosine has been found to be a suitable ligand for the study of adenosine receptors in rat brain synaptic membranes. 2. Binding sites labelled by [3H]-2-chloroadenosine had a high affinity with a KD value of 23.5 nM. 3. Binding is heat sensitive, pH dependent and probably involves protein molecules. 4. The IC50 values for 2-chloroadenosine, adenosine, L-N6-phenylisopropyladenosine and D-N6-phenylisopropyladenosine, N6-cyclohexyladenosine and adenosine-5'-N-ethyl-carboxamide inhibition of [3H]2-chloroadenosine binding are in good agreement with the values obtained in studies of the ability of these compounds to inhibit adenylate cyclase, suggesting that [3H]-2-chloroadenosine binding sites reported here are comparable to the adenosine A1 receptor site. 5. There are regional differences in [3H]-2-chloroadenosine binding to brain membranes. 6. This difference is probably due to the discrepancies in the number of binding sites, and is probably not caused by changing affinities of receptors to the ligand.     

Effects of fixation on routine,special and immunohistochemical stains: introduction to a symposium for the Biological Stain Commission

Orcein was first proposed as an elastic fiber stain by Taenzer in 1890, and has proved very useful for the purpose. It is an important constituent of the author's “Quad” stain. Unfortunately not all orcein samples have proved equally satisfactory, whether they are derived from the lichens from which the dye was originally prepared or have been manufactured by a synthetic process. At the present time several brands are available, and two of the brands of the synthetic product investigated have not proved to be the same thing; one of the latter proves only fair as an elastin stain, the other is one of the best samples the author has ever tried.     

Local spread of classical swine fever upon virus introduction into The Netherlands: Mapping of areas at high risk

Background

In the recent past, the introduction of Classical Swine Fever Virus (CSFV) followed by between-herd spread has given rise to a number of large epidemics in The Netherlands and Belgium. Both these countries are pork-exporting countries. Particularly important in these epidemics has been the occurrence of substantial "neighborhood transmission" from herd to herd in the presence of base-line control measures prescribed by EU legislation. Here we propose a calculation procedure to map out "high-risk areas" for local between-herd spread of CSFV as a tool to support decision making on prevention and control of CSFV outbreaks. In this procedure the identification of such areas is based on an estimated inter-herd distance dependent probability of neighborhood transmission or "local transmission". Using this distance-dependent probability, we derive a threshold value for the local density of herds. In areas with local herd density above threshold, local transmission alone can already lead to epidemic spread, whereas in below-threshold areas this is not the case. The first type of area is termed 'high-risk' for spread of CSFV, while the latter type is termed 'low-risk'.

Results

As we show for the case of The Netherlands, once the distance-dependent probability of local transmission has been estimated from CSFV outbreak data, it is possible to produce a map of the country in which areas of high-risk herds and of low-risk herds are identified. We made these maps even more informative by estimating border zones between the two types of areas. In these border zones the risk of local transmission of infection to a nearby high-risk area exceeds a certain level.

Conclusion

The risk maps provide an easily understandable visualization of the spatial heterogeneities in transmission risk. They serve as a tool for area-specific designs of control strategies, and possibly also for spatial planning of areas where livestock farming is allowed. Similar risk maps can in principle be constructed for other highly-transmissible livestock infections that spread via neighborhood transmission.

     

Quantification of Free Fatty Acids in Human Cerebrospinal Fluid

Free fatty acids (FFA) in cerebrospinal fluid (CSF) are well-recognized markers of brain damage in animal studies. Information is limited regarding human CSF in both normal and pathological conditions. Samples of CSF from 73 patients, who had undergone lumbar puncture for medically indicated reasons, came from a core laboratory upon completion of ordered tests. Using high performance liquid chromatography, mean FFA concentrations (g/L ± SEM) were: arachidonic 26.14 ± 3.44; docosahexaenoic 60.74 ± 5.70; linoleic 105.07 ± 10.98; myristic 160.38 ± 16.17; oleic 127.91 ± 10.13; and palmitic 638.34 ± 37.27. No differences in FFA concentrations were seen with gender, race, age, and/or indication for lumbar puncture. This is the first study to document normal human CSF FFA concentrations in a large series. Further characterization of FFA in pathological conditions may provide markers for evaluating clinical treatments and assisting in prognostication of neurological disease.     

News from the Biological Stain Commission No. 5

In this fifth issue of News from the Biological Stain Commission (BSC), under the heading of Regulatory Affairs, the BSC's International Affairs Committee provides more information from the meeting of the International Standards Organization ISO/TC 212 Committee that took place on June 2–4, 2008 at Vancouver, Canada. In addition, we give an update on the current situation regarding the supplies of hematoxylin.