Recombination between a thermosensitive kanamycin resistance factor and a nonthermosensitive multiple-drug resistant factor

The thermosensitive kanamycin (KM) resistance factor, R(KM)(t), and a nonthermosensitive multiple-drug resistance factor, R(100), were simultaneously introduced into Escherichia coli and Salmonella typhimurium. The temperature sensitivity of both R factors remained unchanged as long as they replicated independently. Under certain conditions, however, a new thermosensitive R factor harboring resistance markers for kanamycin, streptomycin (SM), and sulfanilamide (SA) was obtained by recombination between the R(KM)(t) and R(100) factors. R factors carrying resistance markers for KM and SA, or for SM and SA, were obtained from the recombinant R(KM SA SM)(t) by spontaneous segregation. Though the R(100) factor has been known as an fi(+) (positive for F-mediated fertility inhibition of its host) type and it does not restrict any coexisting phages, the thermosensitive recombinants of R(100) with R(KM)(t) and their segregants were found to be fi(-) and to restrict the replication of all T-even phages, as does the R(KM)(t) factor. Double infection immunity was not observed between the R(KM)(t) and R(100) factors.

Isolation of gibberellins A26 and A 27 and their glucosides from immature seeds of Pharbitis nil

Two new gibberellins, gibberellins A26 and A27 (GA26 and GA27), and their glucosides have been isolated from immature seeds of Japanese morning-glory (Pharbitis nil), together with GA8 and its glucoside. GA26, GA27 and their glucosides showed only slight growth-promoting activities on seedlings of rice, dwarf maize and cucumber.

Isolation of two new gibberellins from immature seeds of Canavalia

Two new gibberellins, Canavalia gibberellin-I (CG-I) and Canavalia gebberellin-II (CG-II), were isolated from immature seeds of sword bean, Canavalia gladiata DC. The molecular formulas C19H22O7 and C19H22O6, were assigned to CG-I and CG-II, respectively, on the basis of high resolution mass, infrared and NMR spectra. The growth-promoting effects of CG-I and CG-II on dwarf maize mutants d 1 and d 5, rice seedlings and dwarf peas, Progress No. 5, are reported.

Intracellular olfactory response of hippocampal neurons in awake, sitting squirrel monkeys

Intracellular recordings of archicortical neurons in a primate have been made and the responses of these neurons in awake, sitting animals have been observed. Electrical stimulation of the olfactory bulbs elicits excitatory postsynaptic potentials in these neurons, which unlike those evoked by septal stimulation, are subliminal for generating spikes. The olfactory and septal pathways may be considered representative of inputs from exteroceptive and interoceptive systems. The findings are discussed in relation to a paradigm for archicortical conditioning.

Isolation of water-soluble gibberellins from immature seeds of Pharbitis nil

The presence of three water-soluble gibberellins was confirmed in immature seeds of morning-glory (Pharbitis nil). The structure of the main component has been elucidated as 2-O-β-glucosyl-gibberellin A3. It shows marked growth-promoting activity on rice seedlings but is far less active on dwarf maize mutants d 1, d 2 and d 5.

Somatic sensory cortical projection areas excited y tactile stimulation of the cat: a triple representation

1. The specific somatic sensory projection from the face to the cerebral cortex of the cat was investigated in two series of experiments. alpha-chloralose and Nembutal were the anaesthetics used.2. Evoked potentials, recorded at the cortical surface, were used in the first series for identifying three discrete projection areas from the face and forelimb. Two of these regions correspond to the established S I and S II projections. The third area, designated S III, was in the dorsal part of the anterior suprasylvian gyrus adjacent to the ansate sulcus.3. Single neurone analysis demonstrated that the cell populations responding to ;tactile' cutaneous stimulation of the face within each of the three specific somatic sensory projection areas had similar static functional properties. Most neurones observed had receptive fields restricted in size and were modality specific. Their receptive fields were mainly contralateral, although some had an ipsilateral extension. Fewer than 10% of cells observed in each specific cortical area were ;non-specific'. Such cells had extensive receptive fields and some of these fired to an auditory stimulus.4. Both field recording and single neurone analysis revealed a somatotopic projection to the S III area as well as to the S I and S II areas.