Involvement of bacteriophage T4 genes in radiation repair

One interpretation of Ebisuzaki's (1966) observation that the functional survival of certain early phage T4 genes is identical in v⁺ and v -infected cells is that the product of the early gene being studied is essential for the successful completion of excision repair (which is known to be mediated by the v gene). An experiment designed to test this hypothesis is described, with results which fully support the idea. Assuming then that this interpretation is valid, it became possible to determine the involvement in excision repair of a much wider range of early genes by establishing whether or not the v allele affects their functional survival. In addition a comparable series of experiments was performed with phages carrying the u.v.-sensitive y mutation which is known to mediate a quite different type of repair in T4-infected cells.The results indicate that genes 1, 30, 42, 43 and 56 are involved in excision repair, but not genes 32, 41, 43 or 44. All these genes are however involved in y-mediated repair. It appears therefore that this latter repair system (which bears some resemblance to that controlled by the rec genes in bacteria) depends on normal phage DNA synthesis for its completion. However the repair synthesis following the excision of pyrimidine dimers in u.v.-irradiated T4 DNA seems distinct from normal DNA synthesis in that it does not involve certain of the early phage genes, and in particular does not utilize the DNA polymerase coded by gene 43. It is suggested that the polymerase activity associated with this repair synthesis is provided by the bacterial Kornberg polymerase pol I.     

Information needs of cancer patients in west Scotland: cross sectional survey of patients' views.

OBJECTIVE: To assess the needs of patients with cancer for information about their condition. DESIGN: Cross sectional survey of patients'' views by means of semistructured interview with questionnaire. SETTING: A regional cancer centre and two university hospitals in west Scotland. SUBJECTS: 250 (93%) of 269 cancer patients invited to participate in study who were selected by age, sex, socioeconomic status, and tumour site to be representative of cancer patients in west Scotland. MAIN OUTCOME MEASURES: Patients'' need to know whether they had cancer, the medical name of their illness, progress through treatment, how treatment works, side effects, chances of cure, and treatment options. RESULTS: 79% (95% confidence interval 73% to 84%) of patients wanted as much information as possible, and 96% (93% to 98%) had a need or an absolute need to know if they had cancer. Most patients also wanted to know the chance of cure (91% (87% to 94%)) and about side effects of treatment (94% (90% to 97%)). When the replies were cross tabulated with patients'' age, sex, deprivation score, and type of treatment there was a linear trend for patients from more affluent areas to want more information and those from deprived areas to want less. There was a strong preference for diagnosis of cancer to be given by a hospital doctor (60% (53% to 66%). CONCLUSION: Almost all patients wanted to know their diagnosis, and most wanted to know about prognosis, treatment options, and side effects.     

Tyrosine Hydroxylation in Betalain Pigment Biosynthesis Is Performed by Cytochrome P450 Enzymes in Beets (Beta vulgaris)

Yellow and red-violet betalain plant pigments are restricted to several families in the order Caryophyllales, where betacyanins play analogous biological roles to anthocyanins. The initial step in betalain biosynthesis is the hydroxylation of tyrosine to form L-DOPA. Using gene expression experiments in beets, yeast, and Arabidopsis, along with HPLC/MS analysis, the present study shows that two novel cytochrome P450 (CYP450) enzymes, CYP76AD6 and CYP76AD5, and the previously described CYP76AD1 can perform this initial step. Co-expressing these CYP450s with DOPA 4,5-dioxygenase in yeast, and overexpression of these CYP450s in yellow beets show that CYP76AD1 efficiently uses L-DOPA leading to red betacyanins while CYP76AD6 and CYP76AD5 lack this activity. Furthermore, CYP76AD1 can complement yellow beetroots to red while CYP76AD6 and CYP76AD5 cannot. Therefore CYP76AD1 uniquely performs the beet R locus function and beets appear to be genetically redundant for tyrosine hydroxylation. These new functional data and ancestral character state reconstructions indicate that tyrosine hydroxylation alone was the most likely ancestral function of the CYP76AD alpha and beta groups and the ability to convert L-DOPA to cyclo-DOPA evolved later in the alpha group.     

Rapid distinction between Leptonema and Leptospira by PCR amplification of 16S-23S ribosomal DNA spacer

Abstract The protein-D2 porin of Pseudomonas aeruginosa is lacking in carbapenem or fluoroquinolone-resistant strains and hence was thought to facilitate the diffusion of these antibiotics. We examined the effect of several antibiotics on the single channel conductivity of protein-D2 in planar lipid bilayers and found that fluoroquinolones and carbapenems at concentrations of around 1 mM caused closure of the protein-D2 channel. Tetracycline, ampicillin, piperacillin, and latamoxef did not exert any detectable effect on the protein-D2 channel activity.     

Distance from Water,Sex and Approach Direction Influence Flight Distances Among Habituated Black Swans

In many animals, response to predators occurs at greater distances the further an individual is from a refuge, but this has rarely been investigated in birds. Here, we test the hypothesis that the further from refuge (i.e. water) a foraging black swan Cygnus atratus is situated, the longer its flight initiation distance (FID) in response to a pedestrian approach on land. As predicted, swans situated farther from water exhibited longer FIDs compared with those closer to the shore. In addition, there was the possibility of an interesting interaction effect (p < 0.061) of sex and direction of approach on FID. Whilst males tended to not alter their response in relation to the angle of approach relative to the water, females tended to respond at longer distances, when approached from the shore than when approached from the land or parallel to the shore. This is one of the first reports of sex differences in FIDs for birds, with sex differences only manifesting themselves under certain approach types. Group size, the order of repeated approaches, and time of day did not influence responses, although starting distance of approach was positively related to FID.