Nucleotide sequence of the genome of an Australian isolate of turnip yellow mosaic tymovirus

The nucleotide sequence of the Club Lake isolate of turnip yellow mosaic virus (TYMV-CL) genomic RNA has been determined. The genome is 6319 nucleotide residues in length and has three major open reading frames (ORFs), two of which overlap. The smallest ORF is proximal to the 3' terminus and encodes the virion protein gene, which has 98% sequence similarity with the virion protein gene reported for the type strain of TYMV. The largest ORF is from nucleotide residues 96 to 5630, and encodes a protein some parts of which show sequence similarities to the possible RNA replicases and nucleotide binding proteins of other viruses. The third ORF is from nucleotide residues 89 to 1975 and overlaps the 5' end of the largest ORF in a manner similar to that found in several animal viral genomes. The function of the protein encoded by this ORF is unknown. The genomes of tymoviruses have, characteristically, an unusually large cytosine content and small guanosine content. This compositional bias is mirrored in the codon and dinucleotide frequencies of the TYMV-CL genome, but is only partially reflected in the amino acid sequences encoded by the genome.

Nucleotide sequence of the genome of eggplant mosaic tymovirus

The sequence of the RNA genome of an isolate of eggplant mosaic tymovirus from Trinidad (EMV-Trin) has been determined. The genome is 6330 nucleotide residues in length and contains three open reading frames; two overlapping genes, whose initiation codons are separated by seven nucleotide residues (nucleotide residues 102-2051 and 109-5628) near the 5' terminus, and the virion protein gene, which is near the 3' terminus (nucleotide residues 5633-6199). The genomes of EMV-Trin and turnip yellow mosaic tymovirus have the same genomic organization and similar nucleotide and encoded amino acid sequences. The nucleotide residues adjacent to the initiation codons of tymoviral overlapping genes have closely similar sequences which may form a weak stem-loop secondary structure that regulates their translation.

Pressure adaptation of Na+/K+-ATPase in gills of marine teleosts

The effects of pressure and temperature on an integral membrane protein, Na+/K+-adenosine triphosphatase (Na+/K+-ATPase), were studied in fish gill membrane preparations from shallow- and deep-living marine teleosts. The inhibition by pressure of maximal velocity of the enzyme is nonlinear, increasing at higher pressures. Na+/K+-ATPases from deep-sea fish were less inhibited by pressure than those of shallow-living species. Habitat temperature also affected the pressure response of the enzyme. As a function of physiological pressure and temperature, the order of increasing pressure-sensitivity was cold, deep-sea less than warm, deep-sea (hydrothermal vents) less than polar = shallow and mid-depth, cold less than shallow, warm. Activation volumes in all species were conserved at 30–60 ml mol-1 at physiological pressures, which may reflect a similar membrane physical state at the actual pressure the animal experiences. Arrhenius plots [In(Na+/K+-ATPase activity) vs 1/T] were steeper for warm-water and shallow-living species than for deep-sea species. The depth at which adaptation was first observed was about 2000 m (approximately equal to 200 atm: 1 atm = 101.3 kPa). The data are consistent with a model of increased membrane fluidity resulting in reduced pressure-sensitivity of Na+/K+-ATPase from deep-sea species.

Diarrhoeal disease: knowledge, attitudes and practices in an aboriginal community

This study was carried out in an Australian Aboriginal community in South Australia on the knowledge, attitudes and practices relating to diarrhoeal disease. Suggestions were sought on appropriate interventions. Dietary causes (including alcohol), factors relating to drinking water, poor environmental hygiene, infective agents and teething were considered by community member to be important in the causation of diarrhoea. Poor personal and domestic hygiene, and the lack of adequate bathing, toilet and laundry facilities were not considered to be important contributory factors. This may reflect the Aboriginal view of hygiene derived from many years of desert living as nomadic hunter-gatherers. The study provides valuable information to enable the selection of appropriate interventions for the control of diarrhoeal disease in this community.

Does isolation of patients with infections induce mental illness?

Forty-one patients admitted into single-bedded isolation cubicles in an infectious diseases unit were assessed for evidence of mental disturbance. By use of the Crown-Crisp Experimental Index as a measure of mental state, the scores for somatic anxiety, free floating anxiety, and the total score were found to be significantly raised on admission, falling towards those found in a control general practice population by the time of discharge from hospital. Higher scores were associated with a past history of mental illness. There was, however, no statistical correlation between the psychological indices and consumption of alcohol, smoking, or patient's sex. Clinically apparent behavioural disturbance, mainly anxiety and agitation, was seen in 12 patients. Overall, patients expressed a preference for single rooms and did not find the isolation rituals disconcerting. The findings indicate that anxiety in patients with acute infections is more related to their illness and referral to hospital than to their imposed isolation. Only those patients with a past psychiatric history are likely to benefit from transfer to an open ward during convalescence.

Nucleotide sequence comparisons of turnip yellow mosaic virus isolates from Australia and Europe

The genomic sequences of four isolates of turnip yellow mosaic virus (TYMV-Cd) from Australia, and three TYMV-1 (type) and three TYMV-2 (cauliflower) isolates from Europe were compared by cDNA-RNA hybridization tests, by analysis of the fragments produced from cDNA-RNA hybrids by restriction endonuclease treatment, and by determining the 3' terminal nucleotide sequences of their coat protein mRNAs. All three methods showed only slight differences (ca. 1%) between the mRNA sequences of different TYMV-1 and TYMV-Cd isolates, and did not distinguish between those groups of isolates. By contrast, the nucleotide sequences of TYMV-2 isolates differed from those of the other TYMVs by ca. 5% (sequence analysis) to 11% (restriction fragment analysis). Published biogeographic evidence has indicated that the TYMV-Cd and TYMV-1 populations probably separated more than 12,000 years ago. This implies that these TYMV genomes have changed at a rate of, at most, 1% in 10,000 years.

The classification of tymoviruses by cDNA-RNA hybridization and other measures of relatedness

The relationships of twelve tymoviruses have been assessed by cDNA-RNA hybridization. In addition, the percentage molar nucleotide composition of the genome of the PD strain of Kennedya yellow mosaic virus and the percentage molar amino acid composition of the coat proteins of cacao yellow mosaic, Kennedya yellow mosaic and turnip yellow mosaic (Cardamine strain) viruses were estimated. These as well as published serological comparisons and genome and coat protein composition determinations were used to compute classifications of tymoviruses using various "metrics", and simple numerical methods were used to compare the classifications. Measures of relatedness estimated from cDNA-RNA hybridization and base ratio data correlated significantly with each other, but were less closely correlated with those calculated from amino acid data, and did not correlate with those calculated from serological tests. The serological relationships correlated significantly with estimates of relatedness calculated from amino acid data, but not with those based on hybridization or base ratio data. The differences between these classifications mostly resulted from the anomalous behaviour of eggplant mosaic virus, its particles are serologically close to those of other tymoviruses that naturally infect species of the tobacco family, whereas in cDNA-RNA hybridization tests eggplant mosaic virus is closest to the tymoviruses that infect legumes. Similar but smaller anomalies in the characteristics of other tymoviruses were also found.

Mechanism of anticoagulant action by protein inhibitors from bovine testes and salmon sperm

A protein inhibitor was isolated from commercial preparations of salmon sperm and its physical and anticoagulant properties were compared with an inhibitor isolated earlier from commercial preparation of bovine testicular hyaluronidase. The inhibitor from bovine source was heat and acid labile and had a molecular weight of approximately equal to 35000 while the one from salmon sperm had a molecular weight of approximately equal to 5700 and was stable to heat and acid. To determine the mechanism of the inhibitory effect, a system of purified components consisting of isolated prothrombin, Factor Xa, Factor Va, Ca++, and vesicles of phosphatidylcholine (PCPS, 25% PS) was used. Included also was dansylarginine N- (3-ethyl-1,5-pentanedidyl) amide (DAPA) which binds newly formed thrombin and yields the time course of prothrombin conversion by virtue of enhanced fluorescence of the DAPA - thrombin complex. The inhibitor of bovine testes was effective only when PCPS was the limiting component suggesting that its action was directed against the phospholipid component of the prothrombinase complex. The inhibitor from salmon sperm was found to lower the rate of conversion of prothrombin to thrombin in an in vitro system where thrombin generation was measured by its action on the chromogenic substrate H-D-Phe-Pip-Arg-pNa (S-2238). It inhibited the conversion of Factor X to Xa and also the the amidolytic cleavage by Factor Xa of chromogenic substrate N-Benz-Ile-Glu-Gly-Arg-pNa (S-2222).

Molecular evolution of viruses; 'trees', 'clocks' and 'modules'

Comparisons of the nucleotide sequences of viral genomes, and derived amino acid sequences, mostly confirm the traditional taxonomic groupings of viruses. These comparisons have also shown unexpected homologies between genes of viruses from different groups previously thought to be unrelated, and between some viral and non-viral genes. Comparisons of the three-dimensional structures of the particle proteins of some viruses have also revealed unexpected relationship, and, together with the sequence homologies, suggest that some ancestral viruses had 'modular' origins. Some of the sequence differences have been used to construct phylogenies. However, there is evidence that viral gene 'molecular clocks' do not always keep time consistently over very long or very short evolutionary time periods. Clues on evolution mostly come from comparative studies of living or fossil organisms. Fossils of viruses are not known, and thus clues of the origins and evolution of viruses are obtained by comparing extant forms. For example, by comparing isolates of different viruses, or strains of viruses, one can infer the properties of their ancestors, and by comparing isolates obtained during an epidemic, and sequentially related to one another, one can observe directly the type and timing of evolutionary changes.

An outpatient survey of antidepressant prescription habits

A review of case notes of patients attending a general hospital psychiatric outpatient clinic revealed that 75% of patients with depressive disorders and 38% of patients with neurotic disorders were prescribed antidepressants. Antidepressants were often prescribed for long periods in low doses and in combination with benzodiazepines. There was less polypharmacy, however, with more sedating antidepressants. The results indicate that clinical prescription habits for antidepressants may still be at some variance with recommendations from the literature.

Dysfunctional attitudes in former psychiatric inpatients

In order to test the hypothesis that patients who are predisposed to depression have an enduring cognitive style, dysfunctional attitudes (Dysfunctional Attitudes Schedule), neuroticism and extraversion (Maudsley Personality Inventory), and severity of depression (Levine-Pilowsky Depression Questionnaire) were measured in a survey of former patients with previous diagnoses of either depressive or nondepressive psychiatric conditions. We found that there were no significant differences in dysfunctional attitudes between these groups of patients and that their scores were similar to those reported for normal populations. There was, however, a correlation between introversion and high dysfunctional attitude scores. Possible implications regarding interactions between cognitive style, personality, and predisposition toward depression are discussed as well as a suggestion that a history of a suicide attempt may predict a poor response to cognitive psychotherapy.

Inhalation of china stone and china clay dusts: relationship between the mineralogy of dust retained in the lungs and pathological changes

A combined clinical, radiological, pathological, and mineralogical study was undertaken on 62 cases referred to the Medical Research Council Pneumoconiosis Unit by the Cardiff Pneumoconiosis Panel as Cornish china clay workers. Considerable pathological lesions were found in the lungs, both nodular and interstitial fibroses being present. Some men had worked with china stone but others had worked entirely with china clay. Nodular fibrosis appeared to be related to a high quartz content of the dust recovered from the lung, whereas among those with a high content of kaolinite dust in the lungs interstitial fibrosis was observed.

The response of human tissues to carbon reinforced epoxy resin

The tissue surrounding carbon fibre reinforced epoxy resin plates applied to forearm and tibial fractures was biopsied in 32 patients at the time the plates were removed. The reaction was minimal and was compared with that in a control group of 16 similar patients in whom stainless steel plates were used. No significant histological differences were found. A series of experiments on rats, in which the histology was studied from 2 to 78 weeks, also showed that there was very little reaction to carbon fibre reinforced plastic.

Plasmalogens in the gill lipids of aquatic animals

Lipids constituted 0.6-2.2% wet wt of the gills of 11 species of aquatic animals (4 bivalves, a crustacean and 6 fishes). Phospholipids, largely phosphatidylcholine (PC) and phosphatidylethanolamine (PE), are major components of all species. The plasmalogen contents of these lipids were 47-291 mumol/g, with the highest values found for bivalve gill total lipids and the catfish phospholipid fraction.

Methods for comparing sequence data such as restriction endonuclease maps or nucleotide sequences of viral nucleic acid molecules

Maps of restriction endonuclease sites in the DNA genomes of orthopoxviruses were compared by computer classification methods. Data from such maps were recorded as qualitative binary information, and gave closely similar dendrograms when different dissimilarity measures and sorting strategies were used for the computations. A method for calculating dendrograms from small data sets, by 'hand', is described in detail to assist those who do not have access to suitable computer programs. The same calculation strategy gave useful classifications of partial nucleotide and amino acid sequences of orthomyxovirus haemagglutinins.

Isolation and anticoagulant properties of polysaccharides of Typha Augustata and Daemonorops species

Polysaccharides were isolated from Dragon's Blood (DB), a red resinous secretion from the fruits of Daemonorops species and from pollens of Typha Augustata (TA) by alcohol precipitation followed by deaminoethylaminoethyl (DEAE) cellulose chromatography. The purified polysaccharides of DB and TA gave specific rotations of [alpha]D20 64 and [alpha]D20 of 80 and their molecular weights by membrane osmometry were approximately 25000 and approximately 30000 respectively. The effect of addition of the polysaccharides on coagulation of pooled normal human plasma was investigated. They were found to accelerate the recalcified plasma times at concentrations below 100 micrograms/ml while inhibiting them at higher concentrations. Their procoagulant properties were due to their effects on the activation of Hageman factor (XII) while the anticoagulant effect was mainly directed towards fibrinogen. Studies of the mechanism of the anticoagulant effect showed that addition of TA polysaccharide inhibited the rate of release of fibrinopeptides by thrombin and also the aggregation of fibrin monomers.

Computed tomography in dystrophia myotonica

The calves and thighs of ten patients with dystrophia myotonica and four normal controls were studied by CT. The morphology of the anterior and posterior muscle groups of the calf and the extensor, flexor and adductor groups of the thigh were studied and their attenuation values analysed. Clinical measurement of muscle force was compared with attenuation values in each muscle group. The principal morphological change observed in diseased muscle was fatty infiltration. The amount of fatty infiltration in the calf muscles paralleled the severity of clinically apparent disease. However, in the thigh, fatty infiltration was observed in the extensors of three of the five patients who clinically had involvement of calf muscles alone. Detailed analysis of attenuation values was no better in detecting diseased muscle except of the adductor group of the thigh in those patients with both proximal and distal lower limb involvement. Comparison between muscle force and attenuation values showed a significant correlation in only the anterior muscle group of the calf in the normal controls and in those patients with clinically apparent disease of the calf muscles alone.