Die Wirkung der Infektionsquellen und der Umwelteinflüsse auf die Erhaltungszucht der Kartoffel

Ohne Zusammenfassung Hans Lembee zum 75. Geburtstag.     

Developmental discord among markers for cholinergic differentiation: in vitro time courses for early expression and responses to skeletal muscle extract

The effects of skeletal muscle extract on the development of CAT, ACh synthesis, high affinity choline uptake, and AChE activities were studied in dissociated ventral spinal cord cultures prepared from 14-day gestational rat embryos. In the absence of muscle extract, the development of CAT and AChE follow biphasic time courses in which they show initial declines followed by periods of steadily increasing activity. In contrast, ACh synthesis and high affinity choline uptake both gradually increase throughout the entire culture period. The presence of muscle extract both prevents the initial decline of CAT and AChE as well as stimulates the rates of development of all four cholinergic markers; however, the degrees and time courses of stimulation differ markedly. The effects of muscle extract on the kinetic and pharmacological properties of ACh synthesis and choline uptake in rat ventral cord cultures were also investigated. Cells treated with muscle extract for 2 days express both high affinity (Km = 1.6 microM) and low affinity (Km = 22 microM) choline uptake mechanisms. Control cells, on the other hand, express only low affinity uptake at this stage but develop a high affinity uptake mechanism by Day 7. During this time both ACh synthesis and high affinity choline uptake become increasingly sensitive to inhibition by hemicholinium-3. These results demonstrate that skeletal muscle factors enhance the development of cholinergic properties in embryonic spinal cord cultures. However, differences in sensitivity to muscle extract concentration, time courses of development, and degrees of stimulation suggest that these changes may involve distinct cellular mechanisms which are differentially affected by skeletal muscle factors.     

Purification and Characterization of a Central Cholinergic Enhancing Factor from Rat Brain: Its Identity as Phosphoethanolamine

A compound that can enhance the apparent synthesis of acetylcholine in cultured explants of the medial septal nucleus has been purified from rat brain and identified as phosphoethanolamine. Acetylcholine synthesis is stimulated two- to threefold in cultures grown for 5 days in the presence of phosphoethanolamine, ethanolamine, or cytidine 5'-diphosphoethanolamine at concentrations above 100 microM. This effect appears to result from an increase in the accumulation of choline via the high-affinity, sodium-dependent uptake mechanism. The development of choline acetyltransferase activity is not affected. Phosphoethanolamine and ethanolamine seem to enhance the ability of developing cholinergic neurons to utilize choline accumulated via the sodium-dependent high-affinity choline uptake mechanism for the preferential production of acetylcholine without increasing the general metabolism of the cultures. Choline itself and its related derivatives are not stimulatory for these effects.     

Macrophage Fc receptors control infectivity and neutralization of canine distemper virus-antibody complexes.

Dogs that are persistently infected or that become moribund after exposure to canine distemper virus (CDV) have antibody that neutralized CDV when tested in dog lung macrophage cultures but failed to neutralize CDV when tested in epithelial, fibroblastic, or lymphatic cells. The antibody attached to protein A and was found in the immunoglobulin G fraction. The antibody bound complement and lysed CDV-infected target cells. The neutralizing activity in macrophages could be abolished (i) by pepsin digestion and removal of Fc portions from the antibody, (ii) by blocking the Fc receptors of macrophages with heat-treated normal dog serum, and (iii) by binding of protein A to Fc portions of the antibody. It was concluded that attachment of the CDV-antibody complex to Fc receptors of macrophages was essential for virus neutralization. If this attachment was hindered, the CDV-antibody complex became infectious for macrophages. In contrast, serum from recovering dogs neutralized CDV when tested in epithelial, fibroblastic, or lymphatic cells as well as in macrophages.     

Real-time dialogue between experimenters and dreamers during REM sleep

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Pflanzenpathologie und Pflanzenzüchtung

Ohne ZusammenfassungVorgetragen auf der Tagung der Gesellschaft zur Förderung deutscher Pflanzenzucht am 6. Juli 1930 in Müncheberg i. M.     

Contributions of different mosquito species to the transmission of lymphatic filariasis in central Nigeria: implications for monitoring infection by PCR in mosquito pools

Background

Monitoring and evaluation are essential to the successful implementation of mass drug administration programmes for LF elimination. Monitoring transmission when it is low requires both large numbers of mosquito vectors and sensitive methods for detecting Wuchereria bancrofti infections in them. PCR-based methods are preferred over classical dissections but the best protocol so far achieved detection of one L₃ Wuchereria bancrofti larva in a pool of 35–50 Anopheles mosquitoes. It also lacks consistency and remains still a costly tool. Hence we decided to improve upon this to achieve detection in a pool of 100 or more by enhancing the quality of the template DNA. Prior to this we also evaluated three vector sampling methods in the context of numbers for monitoring.

Methods

Human landing, pyrethrium spray and light traps catches were conducted concurrently at sites in an LF endemic district in Ghana and the numbers obtained compared. Two DNA extraction methods; Bender buffer and phenol/chloroform purification, and DNAeasy Tissue kit (Quaigen Inc) were used on pools of 25, 50, 75 100 and 150 mosquitoes each seeded with one L₃ or its quivalent amount of DNA. Then another set of extracted DNA by the two methods was subjected to Dynal bead purification method (using capture oligonucleotide primers). These were used as template DNA in PCR to amplify W. bancrofti sequences. The best PCR result was then evaluated in the field at five sites by comparing its results (infections per 1000 mosquitoes) with that of dissection of roughly equal samples sizes.

Results

The largest numbers of mosquitoes were obtained with the human landing catches at all the sites sampled. Although PCR detection of one L₃ in pools of 25, 50 and 75 mosquitoes was consistent irrespective of the extraction method, that of one L₃ in 100 was only achieved with the kit-extracted DNA/Dynal bead purification method. Infections were found at only two sites by both dissection and pool-screening being 14.3 and 19 versus 13.4 and 20.1 per 1000 Anopheles mosquitoes respectively, which were not statistically significant

Discussion and conclusion

HLC still remains the best option for sampling for the large numbers of mosquitoes required for monitoring transmission during MDA programmes, when vector population densities are high and classical indices of transmission are required. One – in – 100 detection is an improvement on previous PCR pool-screening methods, which in our opinion was a result of the introduction of the extra step of parasite DNA capture using Dynal/beads. As pool sizes increase the insects DNA will swamp parasite DNA making the latter less available for an efficient PCR, therefore we propose either additional steps of parasite DNA capture or real-time PCR to improve further the pool screening method. The study also attests also to the applicability of Katholi et al's algorithm developed for determining onchocerciasis prevalence in LF studies.     

A zebrafish model of lethal congenital contracture syndrome 1 reveals Gle1 function in spinal neural precursor survival and motor axon arborization

In humans, GLE1 is mutated in lethal congenital contracture syndrome 1 (LCCS1) leading to prenatal death of all affected fetuses. Although the molecular roles of Gle1 in nuclear mRNA export and translation have been documented, no animal models for this disease have been reported. To elucidate the function of Gle1 in vertebrate development, we used the zebrafish (Danio rerio) model system. gle1 mRNA is maternally deposited and widely expressed. Altering Gle1 using an insertional mutant or antisense morpholinos results in multiple defects, including immobility, small eyes, diminished pharyngeal arches, curved body axis, edema, underdeveloped intestine and cell death in the central nervous system. These phenotypes parallel those observed in LCCS1 human fetuses. Gle1 depletion also results in reduction of motoneurons and aberrant arborization of motor axons. Unexpectedly, the motoneuron deficiency results from apoptosis of neural precursors, not of differentiated motoneurons. Mosaic analyses further indicate that Gle1 activity is required extrinsically in the environment for normal motor axon arborization. Importantly, the zebrafish phenotypes caused by Gle1 deficiency are only rescued by expressing wild-type human GLE1 and not by the disease-linked Fin(Major) mutant form of GLE1. Together, our studies provide the first functional characterization of Gle1 in vertebrate development and reveal its essential role in actively dividing cells. We propose that defective GLE1 function in human LCCS1 results in both neurogenic and non-neurogenic defects linked to the apoptosis of proliferative organ precursors.     

Complement C3c and related protein biomarkers in amyotrophic lateral sclerosis and Parkinson's disease

We have used quantitative 2D gel electrophoresis to analyze serum proteins from 422 patients with neurodegenerative diseases and normal individuals in an unbiased approach to identify biomarkers. Differences in abnormal serum levels were found between amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and related disorders for 34 protein biomarker spots, nine of which were related to the complement system. Of these nine, four spots originated from the Complement C3b-alpha-chain (C3c(1), C3c(2a), C3c(2b), and C3dg). The C3c spots (C3c(1), C3c(2a), and C3c(2b)) had the same amino acid sequence and glycosylation, though only C3c(1) was phosphorylated. In addition, Complement Factors H, Bb, and Pre-Serum amyloid protein displayed different serum concentrations in ALS, PD, and normal sera, whereas Complement C4b gamma-chain and Complement Factor I did not. The differential expression of the complement proteins provides potentially useful biomarkers as well as evidence for the involvement of inflammatory processes in the pathogenesis of ALS and PD.