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1.
2.
In order to determine the vector species of tsutsugamushi disease in Korea, chiggers were individually dissected, and internal contents were tested for Rickettsia tsutsugamushi organisms by means of indirect FA test, and each exoskeleton was mounted on slide for identification. Among 4,142 chiggers collected from 48 Apodemus agrarius at nine different localities during the period of July-November, 1989, 990 chiggers of 10 species of Trombiculidae were dissected and tested. Rickettsiae were confirmed in two Leptotrombidium pallidum larvae out of 447 tested, giving 0.4% of the infection rate. The chiggers of the other species tested were found negative. 相似文献
3.
Functional relationship among the gene clusters encoding F7(1), F7(2), F9, and F11 fimbriae of human uropathogenic Escherichia coli. 总被引:8,自引:3,他引:5 下载免费PDF全文
I Van Die I Van Megen E Zuidweg W Hoekstra H De Ree H Van den Bosch H Bergmans 《Journal of bacteriology》1986,167(1):407-410
The P fimbrial gene clusters encoding the serologically different F7(1), F7(2), F9, and F11 fimbriae were compared functionally. The results show that these gene clusters are closely related. 相似文献
4.
P F Franck J M De Ree B Roelofsen J A Op den Kamp 《Biochimica et biophysica acta》1984,778(3):405-411
The non-specific phospholipid transfer protein purified from bovine liver has been used to modify the phospholipid content and phospholipid composition of the membrane of intact human erythrocytes. Apart from an exchange of phosphatidylcholine between the red cell and PC-containing vesicles, the protein appeared to facilitate net transfer of phosphatidylcholine from the donor vesicles to the erythrocyte and sphingomyelin transfer in the opposite direction. Phosphatidylcholine transfer was accompanied by an equivalent transfer (on a molar basis) of cholesterol. An increase in phosphatidylcholine content in the erythrocyte membrane from 90 to 282 nmol per 100 microliters packed cells was observed. Phospholipase C treatment of modified cells showed that all of the phosphatidylcholine which was transferred to the erythrocyte was incorporated in the lipid bilayer. The nonspecific lipid transfer protein used here appeared to be a suitable tool to modify lipid content and composition of the erythrocyte membrane, and possible applications of this approach are discussed. 相似文献
5.
The presence of peptidergic neuronal networks in the brain and the modulating action of neuropeptides on brain functions as evidenced by their behavioral influence in particular support the concept that the brain like the peripheral endocrine glands is an endocrine target organ which is as sensitive to treatment with neuropeptides as the peripheral glands are to pituitary hormones. Animal and human data are reviewed showing that neuropeptides related to ACTH/MSH affect motivational and attentional processes and that those related to vasopressin are involved in memory processes. Since these functions decline during aging it is postulated that a decreased bioavailability of neuropeptides in brain of elderly people is associated with specific disturbances in mental performance. Thus, the decreased mental ability of the aged may be restored by treatment with neuropeptides particularly those with little, if any, peripheral, endocrine activity, like the ACTH neuropeptide Org 2766 and the vasopressin neuropeptide DGAVP. 相似文献
6.
Fred A. Opmeer J. Peter H. Burbach Victor M. Wiegant Jan M. van Ree 《Life sciences》1982,31(4):323-328
The influence of chronic morphine exposure on the biotransformation of β-endorphin (βE) was investigated using the myenteric plexus-longitudinal muscle of guinea-pig ileum. A membrane preparation was incubated with βE and the degradation of βE as well as the accumulation of several βE fragments in the incubation medium were followed with time. The levels of peptides were determined by specific radioimmunoassays after separation by high-pressure liquid chromatography. It was found that exposure to morphine did not affect the disappearance of βE, but altered the time course of accumulation of βE fragments. In fact, the accumulation of γ-endorphin, α-endorphin and des-tyrosine1-α-endorphin was enhanced, while that of des-tyrosine1-γ-endorphin was not changed. Additionally, the disappearance of γ-endorphin appeared to be stimulated by morphine exposure. These data provide evidence that the fragmentation of βE is changed by chronic morphine exposure in such a way that the turn-over of γ-endorphin is increased. 相似文献
7.
Dependence creating properties of lipotropin C-fragment (beta-endorphin): evidence for its internal control of behavior 总被引:3,自引:0,他引:3
The C-fragment of lipotropin (β-endorphin) possesses reinforcing properties, in that this peptide, like heroin, induced intraventricular self-administering behavior in drug naive rats. Only mild behavioral signs reminiscent of physical dependence were present. After injection into the nucleus raphé magnus, C-Fragment appeared to act as a discriminative stimulus in rats trained to discriminate fentanyl from saline. These data indicate that naturally occuring C-Fragment exerts powerful control of behavior, which may be of significance for the understanding of the mechanisms underlying opiate dependence. 相似文献
8.
E. Acquas E. Carboni R. H. A. de Ree M. Da Prada G. Di Chiara 《Journal of neurochemistry》1992,59(1):326-330
The effect of the systemic administration of a novel, orally active, catechol-O-methyltransferase (COMT) inhibitor, Ro 40-7592, on the in vivo extracellular concentrations of dopamine (DA) and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), was studied by transcerebral microdialysis in the dorsal caudate of freely moving rats. Ro 40-7592 (at doses of 3.0, 7.5, and 30 mg/kg p.o.) elicited a marked and long-lasting reduction of HVA, and at doses of 7.5 and 30 mg/kg, an increase of DOPAC output, but it failed to increase DA output. The administration of L-beta-3,4-dihydroxyphenylalanine (L-DOPA, 20 and 50 mg/kg p.o.) with a DOPA decarboxylase inhibitor (benserazide) increased both HVA and DOPAC output, but failed to modify significantly extracellular DA concentrations in dialysates; in contrast, combined administration of L-DOPA+benserazide with Ro 40-7592 (30 mg/kg p.o.) resulted in a significant increase in DA output. Ro 40-7592 prevented the L-DOPA-induced increase in HVA output and markedly potentiated the increase in DOPAC output. To investigate to what extent the increase in extracellular DA concentrations was related to an exocitotic release, tetrodotoxin (TTX) sensitivity was tested. Addition of TTX to Ringer, although abolishing DA output in the absence of L-DOPA, partially reduced it in the presence of L-DOPA+Ro 40-7592 and even more so after L-DOPA without the COMT inhibitor. The results of the present study suggest that metabolism through COMT regulates extracellular concentrations of DA formed from exogenously administered L-DOPA but not of endogenous DA.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
9.
Matthew P. Nelsen Robert Lücking C. Kevin Boyce H. Thorsten Lumbsch Richard H. Ree 《Geobiology》2020,18(1):3-13
The early‐successional status of lichens in modern terrestrial ecosystems, together with the role lichen‐mediated weathering plays in the carbon cycle, have contributed to the long and widely held assumption that lichens occupied early terrestrial ecosystems prior to the evolution of vascular plants and drove global change during this time. Their poor preservation potential and the classification of ambiguous fossils as lichens or other fungal–algal associations have further reinforced this view. As unambiguous fossil data are lacking to demonstrate the presence of lichens prior to vascular plants, we utilize an alternate approach to assess their historic presence in early terrestrial ecosystems. Here, we analyze new time‐calibrated phylogenies of ascomycete fungi and chlorophytan algae, that intensively sample lineages with lichen symbionts. Age estimates for several interacting clades show broad congruence and demonstrate that fungal origins of lichenization postdate the earliest tracheophytes. Coupled with the absence of unambiguous fossil data, our work finds no support for lichens having mediated global change during the Neoproterozoic‐early Paleozoic prior to vascular plants. We conclude by discussing our findings in the context of Neoproterozoic‐Paleozoic terrestrial ecosystem evolution and the paleoecological context in which vascular plants evolved. 相似文献
10.
Acetylation changes tau interactome to degrade tau in Alzheimer’s disease animal and organoid models
Heesun Choi Haeng Jun Kim Jinhee Yang Sehyun Chae Wonik Lee Sunwoo Chung Jisoo Kim Hyunjung Choi Hyeseung Song Chang Kon Lee Jae Hyun Jun Yong Jae Lee Kyunghyeon Lee Semi Kim Hye‐ri Sim Young Il Choi Keun Ho Ryu Jong‐Chan Park Dongjoon Lee Sun‐Ho Han Daehee Hwang Jangbeen Kyung Inhee Mook‐Jung 《Aging cell》2020,19(1)
Alzheimer's disease (AD) is an age‐related neurodegenerative disease. The most common pathological hallmarks are amyloid plaques and neurofibrillary tangles in the brain. In the brains of patients with AD, pathological tau is abnormally accumulated causing neuronal loss, synaptic dysfunction, and cognitive decline. We found a histone deacetylase 6 (HDAC6) inhibitor, CKD‐504, changed the tau interactome dramatically to degrade pathological tau not only in AD animal model (ADLPAPT) brains containing both amyloid plaques and neurofibrillary tangles but also in AD patient‐derived brain organoids. Acetylated tau recruited chaperone proteins such as Hsp40, Hsp70, and Hsp110, and this complex bound to novel tau E3 ligases including UBE2O and RNF14. This complex degraded pathological tau through proteasomal pathway. We also identified the responsible acetylation sites on tau. These dramatic tau‐interactome changes may result in tau degradation, leading to the recovery of synaptic pathology and cognitive decline in the ADLPAPT mice. 相似文献