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41.
42.
Maria Reuter Margaretha K. S. Gustafsson Katja Mäntylä Cornelius J. P. Grimmelikhuijzen 《Zoomorphology》1996,116(3):111-122
The organization of the nervous system ofDendrocoelum lacteum (Tricladida, Paludicola, Dendrocelidae) andPolycelis tenuis (Tricladida, Paludicola, Planariidae) was studied by immunocytochemical double staining, using neuropeptide RFamide and serotonin
(5-HT) antisera on cryosections. The study confirmed the status of the main nerve cords (MCs) as the most important and stable
of the longitudinal cords and supported the hypothesis of a common phylogenetic origin of the MCs in flatworms. The ganglion-like
structures along the MCs at the beginning of transverse commissures and laterla branches showed a close contact with ventral
fibres of the submuscular nerve plexus indicating an origin from crossing points of insunken ring commissures. The distributional
pattern and morphology of the RFamide-IR cell bodies inD. lacteum corresponded to that of neurosecretory cells. Most RFamide-IR cells were unipolar and rounded while 5-HT-IR cells were uni-
bi- and multipolar. The neutropile consisted of a dense RFamide-IR and a loose 5-HT-IR network. RFamide dominated in all parts
of the genital plexus. 相似文献
43.
M. J. Taherzadeh G. Lidén L. Gustafsson C. Niklasson 《Applied microbiology and biotechnology》1996,46(2):176-182
Physiological effects of deficiency of pantothenate, a necessary precursor in the synthesis of coenzyme A, were studied using
the yeast strain Saccharomyces cerevisiae CBS 8066. Cells were grown on defined media in anaerobic batch cultures with glucose (50 g/l) as the carbon and energy source.
Batch cultures containing more than 60 μg/l pantothenate showed no significant differences with respect to growth rates and
product yields. However, with an initial pantothenate concentration of 30 μg/l, the average glucose consumption rate was 50%
lower than in rich medium and, at even lower concentrations of pantothenate, the culture did not consume all the glucose in
the medium. Furthermore, pantothenate deficiency caused the acetate and pyruvate yields to increase and the biomass yield
to decrease, compared to the yields in pantothenate-rich medium. The increased acetate formation could be counteracted by
initial addition of acetate to the medium, and thereby the glycerol yield could be decreased. An initial addition of acetate
of 1.6 g/l to pantothenate-deficient medium (30 μg/l) caused a 35% decrease in glycerol yield and a 6% increase in ethanol
yield. Furthermore, the time required for complete conversion of the glucose decreased by 40%. Acetate addition affected the
acetate and glycerol yields in a similar way in pantothenate-rich medium (1000 μg/l) also.
Received: 27 December 1995/Received revision: 3 May 1996/Accepted: 9 May 1996 相似文献
44.
The nervous system of Tricladida. I. Neuroanatomy ofProcerodes littoralis (Maricola,Procerodidae): An immunocytochemical study 总被引:3,自引:0,他引:3
Maria Reuter Margaretha K. S. Gustafsson Cecilia Sahlgren David W. Halton Aaron G. Maule Chris Shaw 《Invertebrate neuroscience : IN》1995,1(2):113-122
The organization of the nervous system ofProcerodes littoralis (Tricladida, Maricola, Procerodidae) was studied by immunocytochemistry, using antibodies to authentic flatworm neuropeptide
F (NPF) (Moniezia expansa). Compared to earlier investigations of the neuroanatomy of tricladid flatworms, the pattern of NPF immunoreactivity inProcerodes littoralis reveals differences in the following respects: 1. Shape and structure of the brain. 2. Number and composition of longitudinal
nerve cords. 3. Shape of branches of, and transverse connections between, main ventral nerve cords. 4. Composition of the
pharyngeal nervous system. The rich innervation by NPF immunoreactive (IR) fibres and cells of the subepithelial muscle layer,
the pharynx musculature and the musculature of the male copulatory apparatus indicates a neurotransmitter or neuromodulatory
influence on muscular activity. 相似文献
45.
The nervous system of Tricladida. II. Neuroanatomy ofDugesia tigrina (Paludicola,Dugesiidae): An immunocytochemical study 总被引:2,自引:0,他引:2
46.
Abstract The firefly luciferase gene, luc , was demonstrated to hold promise as a specific marker for monitoring of genetically modified bacteria in the environment. PCR amplification and bioluminescence procedures were modified and compared for environmental monitoring of luc -tagged bacteria, using Escherichia coli as a model. The methods were used to track luc -tagged bacterial cells added to intact sediment core microcosms. Detection limits for the luc -tagged cells were the following, expressed as cells per 0.5 g of sediment: 102 , by PCR amplification; 103 , by whole cell luminescence; and 103 −104 , by measurement of luminescence in cell extracts. 相似文献
47.
48.
Sture Forsgren Lars Franzén Yan Liang Hans Gustafsson Roger Henriksson 《The Histochemical journal》1994,26(8):630-640
Summary It is well-known that a large number of factors can influence the expression of neuropeptides in the nervous system. In the present study, the effects of unilateral and bilateral irradiation to the rat head and neck on the expression of neuropeptides in the innervation of the submandibular gland and in the ganglionic cells of the submandibular ganglion was examined ten days and six months after treatment. Antisera directed against enkephalin and bombesin and immunohistochemical methods were used. The effects of bilateral irradiation on the staining pattern of various neuropeptides in the cervical spinal cord were also studied. In the submandibular gland and in the submandibular ganglionic cells, there was a markedly increased neuropeptide expression ten days after bilateral treatment, as seen after staining with both antisera used, while no changes occurred after unilateral treatment. Six months after treatment, the pattern of neuropeptide expression in the submandibular gland/ganglion corresponded to that seen in controls. Irradiation did not lead to any changes in the staining pattern of neuropeptides in the spinal cord. The observations show that there is a great complexity in the susceptibility of nervous tissues to radiotherapy with respect to influences on the expression of neuropeptides. 相似文献
49.
A. J. Soitamo G. Zhou A. K. Clarke G. Öquist E-M. Aro P. Gustafsson 《Plant molecular biology》1994,26(2):709-721
The unicellular cyanobacterium Synechococcus sp. PCC 7942 has three psbA genes encoding two different forms of the photosystem II reaction centre protein D1 (D1:1 and D1:2). The level of expression of these psbA genes and the synthesis of D1:1 and D1:2 are strongly regulated under varying light conditions. In order to better understand the regulatory mechanisms underlying these processes, we have constructed a strain of Synechococcus sp. PCC 7942 capable of over-producing psbA mRNA and D1 protein. In this study, we describe the over-expression of D1:1 using a tac-hybrid promoter in front of the psbAI gene in combination with lacI
Q
repressor system. Over-production of D1:1 was induced by growing cells for 12 h at 50 mol photons m-2 s-1 in the presence of 40 or 80 g/ml IPTG. The amount of psbAI mRNA and that of D1:1 protein in cells grown with IPTG was three times and two times higher, respectively. A higher concentration of IPTG (i.e., 150 g/ml) did not further increase the production of the psbAI message or D1:1. The over-production of D1:1 caused a decrease in the level of D1:2 synthesised, resulting in most PSII reaction centres containing D1:1. However, the over-production of D1:1 had no effect on the pigment composition (chlorophyll a or phycocyanin/number of cells) or the light-saturated rate of photosynthesis. This and the fact that the total amounts of D1 and D2 proteins were not affected by IPTG suggest that the number of PSII centres within the membranes remained unchanged. From these results, we conclude that expression of psbAI can be regulated by using the tac promoter and lacI
Q
system. However, the accumulation of D1:1 protein into the membrane is regulated by the number of PSII centres. 相似文献
50.
OBJECTIVE--To evaluate the risk of acute childhood leukaemia in areas of Sweden contaminated after the Chernobyl reactor accident in April 1986. DESIGN--Population based study of childhood leukaemia diagnosed during 1980-92. SETTING--Coordinates for places of residence of all 1.6 million children aged 0-15 years; aerial mapped areas of Sweden heavily contaminated after the Chernobyl accident. SUBJECTS--888 children aged 0-15 years with acute leukaemia diagnosed in Sweden during 1980-92, identified with place of birth and residence at diagnosis. MAIN OUTCOME MEASURES--Risk of leukaemia in areas contaminated after the Chernobyl accident compared with the rest of Sweden and in the same areas before the accident. RESULTS--During six and a half years of follow up after the accident the odds ratio for acute leukaemia was 0.9 (95% confidence interval 0.6 to 1.4) in highly contaminated areas (> or = 10 kBq/m2) compared with the same areas before the accident. For the subgroup acute lymphoblastic leukaemia in children aged under 5 years at diagnosis the odds ratio was 1.5 (0.8 to 2.6). For all cases diagnosed after May 1986 in highly contaminated areas compared with areas of low contamination the odds ratio was 0.9 (0.7 to 1.3). For acute lymphoblastic leukaemia in children aged under 5 years at diagnosis the odds ratio was 1.2 (0.8 to 1.9) in highly contaminated areas compared with areas of low contamination. Dose-response analysis showed no correlation between the degree of contamination and the incidence of childhood leukaemia. CONCLUSION--There has been no significant increase in the incidence of acute childhood leukaemia in areas of Sweden contaminated after the Chernobyl reactor accident. 相似文献