Rhythms of differentiation and diacylglycerol in Neurospora.

Although the fungus Neurospora crassa is a relatively simple lower eukaryote, its circadian system may be more complex than previously thought. In this paper we review evidence suggesting that there may be several output pathways coupled in complex ways to a single oscillator, or that there may be more than one oscillator driving independent output pathways. We have described two new rhythms in Neurospora that are not tightly coupled to the rhythm of conidiation bands that is the standard assay for the state of the Neurospora circadian clock. The first is a rhythm in the timing of differentiation, i.e. the production of aerial hyphae and spores. Large regions of the mycelium differentiate synchronously, as if responding to a spatially widespread signal. This rhythm may be distinct from the timer that sets the determination switch controlling the spatial pattern of conidiation bands. The second new rhythm is an oscillation in the levels of the neutral lipid diacylglycerol (DAG). This rhythm is found in all regions of a colony and is not always in phase with the rhythm of conidiation bands. The DAG rhythm shares some characteristics with the differentiation rhythm and has the potential to act as the signal that induces rhythmic differentiation.     

Cellular autonomy of theGonyaulax circadian clock

Because of the long term persistence of free-running circadian rhythms in populations of unicells, several investigators have considered, but not demonstrated, a possible role for intercellular interaction in maintaining synchrony between individual cells. The experiments described here were designed to test more critically the possibility that there is interaction between cells, including those possessing only small phase differences. None was detected; the bioluminescent glow of the mixed cultures matched the algebraic sum of the independent control cultures.     

Physical function, disease activity, and health-related quality-of-life outcomes after 3 years of adalimumab treatment in patients with ankylosing spondylitis

Introduction  

We evaluated the three-year impact of adalimumab on patient-reported physical function and health-related quality-of-life (HRQOL) outcomes in patients with active ankylosing spondylitis (AS).     

A real-time qPCR assay for the detection of the nifH gene of Methanobrevibacter smithii, a potential indicator of sewage pollution

Aims: To degrade ether‐type polyurethane (ether‐PUR), ether‐PUR–degrading micro‐organism was isolated. Moreover, ether‐PUR–degrading mechanisms were analysed using model compounds of ether‐PUR. Methods and Results: A fungus designated as strain PURDK2, capable of changing the configuration of ether‐PUR, has been isolated. This isolated fungus was identified as Alternaria sp. Using a scanning electron microscope, the grid structure of ether‐PUR was shown to be melted and disrupted by the fungus. The degradation of ether‐PUR by the fungus was analysed, and the ether‐PUR was degraded by the fungus by about 27·5%. To analyse the urethane‐bond degradation by the fungus, a degraded product of ethylphenylcarbamate was analysed using GC/MS. Aniline and ethanol were detected by degradation with the supernatant, indicating that the fungus secreted urethane‐bond–degrading enzyme(s). PURDK2 also degraded urea bonds when diphenylmethane‐4,4′‐dibutylurea was used as a substrate. Conclusions: The enzyme(s) from PURDK2 degraded urethane and urea bonds to convert the high molecular weight structure of ether‐PUR to small molecules; and then the fungus seems to use the small molecules as an energy source. Significance and Impact of the Study: Ether‐PUR–degrading fungus, strain PURDK2, was isolated, and the urethane‐ and urea‐bonds–degrading enzymes from strain PURDK2 could contribute to the material recycling of ether‐PUR.     

The TAPS project. 17: Readmission to hospital for long term psychiatric patients after discharge to the community.

OBJECTIVE--To identify risk factors which increase the likelihood of readmission for long stay psychiatric patients after discharge from hospital. DESIGN--Follow up for five years of all long stay patients discharged from two large psychiatric hospitals to compare patients readmitted and not readmitted. SETTING--Friern and Claybury Hospitals in north London and their surrounding catchment areas. Most patients were discharged to staffed or unstaffed group homes. SUBJECTS--357 psychiatric patients who had been in hospital for over one year, of whom 118 were "new" long stay and 239 "old" long stay patients. MAIN OUTCOME MEASURES--Readmission to hospital and length of subsequent stay. RESULTS--Of all discharged patients 97 (27%) were readmitted at some time during the follow up period, 57 (16%) in the first year after discharge, and 31 (9%) then remained in hospital for over a year. The best explanatory factors for readmission were: male sex, younger age group, high number of previous admissions, higher levels of symptomatic and social behavioural disturbance, a diagnosis of manic-depressive psychosis, and living in a non-staffed group home. CONCLUSIONS--During the closure of psychiatric hospitals, facilities need to be preserved for acute relapses among long term, and especially younger, discharged patients. Staffed group homes may help prevent relapse and reduce the number of admission beds required.     

Assessment of inhibition kinetics of the growth of strain P5 on pentachlorophenol under steady-state conditions in a nutristat

A bacterium degrading pentachlorophenol (PCP) as the only source of carbon and energy was grown in a nutristat, i.e., a continuous culture with on-line measurement and control of the substrate concentration. We improved the PCP nutristat by incorporation of a personal computer with a proportional integral derivative (PID) algorithm for controlling the medium feed pump. The controlled value deviated from the average (set-point) value by 1% maximally. In the PCP nutristat (30°C), the steadystate dilution rate, and hence, specific growth rate, showed a maximum value of 0.142±0.004 h^-1 at set-point PCP concentrations between 37 and 168 M. At PCP concentrations above 168 M, the steady-state growth rate decreased because of inhibition. The growth yield coefficient was not seriously affected by the PCP concentration, suggesting that uncoupling was not the inhibitory mechanism. It was concluded that the PCP nutristat is very useful for establishing steady-state conditions that maintain growth-inhibitory PCP concentrations and high cell concentrations, conditions for which the chemostat is not suitable.Abbreviations MCA Metabolic control analysis - NTA Nitrilotriacetic acid - PCP Pentachlorophenol - PID Proportional integral derivative     

Synthesis of thiol-containing analogues of puromycin and a study of their interaction with N-acetylphenylalanyl-transfer ribonucleic acid on ribosomes to form thioesters

1. The thiol-containing analogue of puromycin, 6-dimethylamino-9-{1′-[3′-(2″-mercapto-3″-phenylpropionamido)-3′-deoxy-β-d-ribofuranosyl]}purine (XVII) in which the primary amino group of the antibiotic is replaced with a thiol grouping, was synthesized chemically (compound XVII is abbreviated to thiopuromycin). 2. Thiopuromycin (XVII) was found to be active in releasing N-[³H]acetylphenylalanine from its tRNA carrier as the thioester, N-acetylphenylalanylthiopuromycin (XIX) in the Escherichia coli ribosomal system. The reaction product (XIX) was synthesized chemically from thiopuromycin and N-acetylphenylalanine and found to be stable to hydrolysis in the standard incubation medium at pH7.6. dl-Phenyl-lactylpuromycin (XXI), the hydroxy analogue of puromycin, was also synthesized chemically and shown to release N-acetylphenylalanine from its tRNA carrier in the E. coli ribosomal system, thus confirming the previous results of Fahnestock et al. [Biochemistry (1970) 9, 2477–2483]. 3. In marked contrast with the results obtained in the E. coli system, both thiopuromycin (XVII) and hydroxypuromycin (XXI) were found to be inactive in releasing N-acetylphenylalanine from its tRNA carrier in the rat liver ribosomal system.     

Circadian spontaneous bioluminescent glow and flashing ofGonyaulax polyedra

Summary A new, fully computerized method for the measurement and analysis of dinoflagellate bioluminescence has been developed and applied to the spontaneous light emission ofGonyaulax polyedra. This light emission consists of a low-level steady glow, and occasional superimposed flashes. The instrumentation distinguishes the two components and records them separately; both exhibit circadian rhythmicity. In this paper we describe the method in detail, and show results for flashing and glow measured under light: dark cycles and under constant light of different intensities. Under constant dim light at 19°C, both rhythms exhibit two peaks during a circadian cycle; the minor ones occur approximately nine hours before the major ones. Under these conditions the major flashing peak occurs early during the subjective night, and the major glow peak at the end, about nine hours later. However, the relative phase angle between glow and flashing peaks varies with light intensity, being as little as 220 min (3.7 h) in the dark under light-dark entrained conditions, to as much as 700 min (11.7 h) in dim light under free-running conditions. The ambient light intensity also affects differentially the amount of light emitted in the two modes of spontaneous luminescence. These results suggest that the controls for the two processes must at some point diverge.