The cysteine transport system of Saccharomyces cerevisiae.

Although Saccharomyces cerevisiae strains had different cysteine uptake activities, they revealed monophasic uptake kinetics and had the same KT (83.3 microM). The optimal pH of cysteine uptake was between 4.5 and 5.0, but the activity was quickly lost if cells were kept in buffer. When the activity was measured in the growth medium, it increased in the presence of EDTA and greatly decreased in the presence of mercuric chloride. Thioglycol as well as metabolic inhibitors such as dinitrophenol and azide were inhibitory. Homocysteine and methionine were competitive and non-competitive inhibitors, respectively. Cysteamine and cysteic acid were not inhibitory. From these observations, we conclude that the system mediating uptake of cysteine is specific (we thus name it the cysteine transport system) and that the cysteine transport system recognizes not only the SH-group but also amino- and carboxyl-groups. In wild-type strains the cysteine transport system was derepressed only when the cells were incubated without any sulfur source. On the other hand, in cysteine-dependent mutants, cysteine uptake activity increased with increase of exogenous supply of cysteine, glutathione or methionine. From this result, we suspect that the cellular cysteine level is the limiting factor for biosynthesis of the cysteine transport system in cysteine-dependent strains.     

Methods to build neural networks for evaluation of state variable patterns

Evaluation of the system state is becoming imperative in supervising and controlling huge systems such as power generation and transmission systems and industrial plants. This paper discusses two methods of building the neural networks: one is based upon backpropagation, and the other is a new method proposed herein. Unlike backpropagation which forms the completely distributed activation structure of neurons, the proposed method enables self-organization of the modules which are activated selectively to an input pattern. The new method not only makes a biologically natural structure of neural network but also shortens considerably the learning time by localizing the links to be updated in the learning process.     

Sequential changes of tau-site-specific phosphorylation during development of paired helical filaments

It has been reported that many tau sites in neurofibrillary tangles (NFT) are abnormally phosphorylated. We investigated the phosphorylation of tau in the hippocampus of nondemented patients and Alzheimer's disease patients by immunostaining with five site-specific antibodies against phosphorylated tau. In the pretangle stage, tau in neuropil threads was phosphorylated at serines 199, 202 and 409, numbered according to the longest human tau isoform, whereas tau in some neuronal soma was phosphorylated at serines 199, 202, 409 and 422. Tau at the stage of NFT was phosphorylated at serine 396 and threonine 231 in addition to serines 199, 202, 409 and 422. In the advanced stage, tau in ghost tangles was phosphorylated mainly at serine 396. These results suggest that the phosphorylation of each site in tau differs among the maturing stages of neurofibrillary change and that abnormal phosphorylation of tau in the neuronal soma occurs at 199, 202, 409 and 422 earlier than at threonine 231 and serine 396.     

Involvement of cytochrome b5 in the oxidative desaturation of linoleic acid to γ-linolenic acid in rat liver microsomes

The effects of antibodies against microsomal electron-transport components on the in vitro activity of Δ⁶-desaturation of linoleic acid to γ-linolenic acid have been studied in intact microsomal membranes of rat liver. Reduced nicotinamide adenine dinucleotide (NADH) or reduced nicotinamide adenine dinucleotide phosphate (NADPH) (0.87 mM) served as electron donors, and effectively prompted the Δ⁶-desaturase activities with yields of about 1.1 to 1.3 nmol per mg of protein in 10 min. Of the two antibodies studied under the same in vitro conditions, i.e., rabbit antisera preparations against rat liver microsomal hydrophilic parts of cytochrome b₅ and NADPH-cytochrome c reductase, only the antibody against cytochrome b₅ demonstrated a marked ability to inhibit the Δ⁶-desaturase activity. This evidence supports a participation of cytochrome b₅ in the Δ⁶-desaturation of linoleic acid and suggests a pathway analogous to the Δ⁹-desaturation of stearyl-CoA.     

Three methods of measuring the location of the egocentre: Their reliability, comparative locations and intercorrelations.

Based on discrepancies between the various assumptions and reports that have been made regarding the location of the egocenter, 3 different methods of measuring its location, which have been previously used or suggested, were studied. These methods were developed by I. P. Howard and W. B. Templeton (1966), S. Funaiski (1962), and C. O. Roelofs (see record 1960-05258-001). The locations of egocenters for 15 Ss were determined 8 times by each method during each of 2 different experimental sessions separated by a week. All 3 methods were found to have high internal consistency as indicated by high alpha coefficients. Two methods were found to have high stability over time as indicated by test-retest correlations. The mean egocenter was found to be located near the corneal plane and near the median plane with Howard and Templeton's and Funaishi's methods, but using Roelofs' method the mean egocenter was found to be located 17 cm behind the corneal plane near the median plane. The intermethod correlations were uniformly low. The lack of intermethod correlation and the different mean locations among the methods suggest that, unless predictive validity is established for the 3 tasks, there is no basis for choosing among the 3 methods. (French summary) (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hepatocyte nuclear factor-1alpha gene and non-insulin-dependent diabetes mellitus in the Japanese population

Since natural proteins are the products of a long evolutionary process, the structural properties of present-day proteins should depend not only on physico-chemical constraints, but also on evolutionary constraints. Here we propose a model for protein evolution, in which membranes play a key role as a scaffold for supporting the gradual evolution from flexible polypeptides to well-folded proteins. We suggest that the folding process of present-day globular proteins is a relic of this putative evolutionary process. To test the hypothesis that membranes once acted as a cradle for the folding of globular proteins, extensive research on membrane proteins and the interactions of globular proteins with membranes will be required.     

Usefulness of argyrophilic nucleolar organizer staining for predicting prognosis of patients with recurrent soft tissue sarcoma

Local recurrence of tumor is a common phenomenon in soft tissue sarcoma (STS) and may be accompanied by an increase in malignant potential. In the present study, an increase of proliferative activity in recurrent tumors compared to primary tumors was observed using a silver stain for nucleolar organizer regions (AgNOR), and its implication for predicting prognosis is assessed. 44 patients with STS showing local tumor recurrence were selected. Local recurrence was defined as new tumor growth more than 2 months after the initial surgery in the same region where the primary tumor occurred. All patients received surgery, followed in 11 patients by adjuvant radiotherapy and/or chemotherapy. The histologic subtype was malignant fibrous histiocytoma in 22 cases, synovial sarcoma in 5, leiomyosarcoma in 4, liposarcoma in 3, malignant schwannoma in 3, and others in 7. The interval between initial surgery and local recurrence ranged from 2 to 72 months. No patients changed from one histological subtype to another. Histological changes included an increase in mitosis, cellularity, and sclerosis in 43.2, 31.8, and 27.3%, respectively. The AgNOR count (mean +/- SD) in recurrent tumors (7.22 +/- 2.59) was significantly higher than that in primary tumors (5.58 +/- 2.28; p < 0.0057), clearly showing a tendency for an increase in proliferative activity during recurrence. The 5-year survival rate of patients with a marked increase (> 4) in AgNOR count (16.7%) was worse than with minor to moderate increases (60.0%; p < 0.02). Marked AgNOR increase was more frequently observed in the tumors located in the head and neck and retroperitoneum (40%) than in other sites (9%). Irrespective of the primary site of tumors, a marked AgNOR increase resulted in an unfavorable prognosis. Multivariate analysis of change in histologic factors including AgNOR, cellularity, mitotic counts, pleomorphism, myxoid change, necrosis, sclerosis, and tumor size showed that increase of AgNOR counts was significant (p < 0.05). The present findings suggest that AgNOR counts can be used as a prognostic factor in recurrent STS.     

Rupture of the common extensor tendon caused by an arthritic spur of the third metacarpophalangeal joint

Infectious peritonitis is a common complication of continuous ambulatory peritoneal dialysis (CAPD). Only one case of CAPD-related peritonitis due to Penicillium sp has previously been reported. We present a second case in which fungal colonies were observed on the inner surface of the CAPD catheter. The infection was successfully treated with catheter removal and intravenous amphotericin B.     

Delayed block transfer function in the frequency domain

When the impulse response of a transfer system is long, it is difficult for the standard cross spectrum method to obtain an accurate estimate of the transfer function by applying the fast Fourier transform (FFT) with a finite length window. The bias error in the estimate is large especially around the resonant frequency of the transfer system. In the paper, therefore, the authors propose an alternative new method to obtain an accurate estimate of the transfer function. The delayed block transfer function is introduced to detect the components that are correlated to the signal in the input window but leak from the output window. Based on these transfer functions, the total characteristics of the transfer system are estimated accurately. In the latter half of the paper, the authors derive the theoretical expressions for the bias errors in the transfer functions estimated by the proposed and the standard methods. By thoroughly comparing the resultant expressions, the superiority and the usefulness of the proposed method are theoretically confirmed. Finally, the simulation experiments show the advantages of the proposed method