No abstract

Two genes encoding distinct glutamate carrier proteins of Escherichia coli B were cloned into an E. coli K-12 strain by using a cosmid vector, pHC79. One of them was the gltS gene coding for a glutamate carrier of an Na+-dependent, binding protein-independent, and glutamate-specific transport system. The content of the glutamate carrier was amplified about 25-fold in the cytoplasmic membranes from a gltS-amplified strain. The gitS gene was located in a 3.2-kilobase EcoRI-MluI fragment, and the gene product was identified as a membrane protein with gn apparent Mr of 35,000 in a minicell system. A gene designated gltP was also cloned. The transport activity of the gitP system in cytoplasmic membrane vesicles from a gltP-amplified strain was driven by respiratory substrates and was independent of the concentrations of Na+, K+, and Li'. An uncoupler, carbonylcyanide m-chlorophenylhydrazone, completely inhibited the transport activities of both systems, whereas an ionophore, mnonensin, inhibited only that of the gltS system. The Kt value for glutamate was 11 ,IM in the gltP system and 3.5 ,IM in the gltS system. L-Aspartate inhibited the glutamate transport of the gltP system but not that of the gitS system. Aspartate was taken up actively by membrane vesicles from the gltP-amplified strain, although no aspartate uptake activity was detected in membrane vesicles from a wild-type E. coli strain. These results suggest that gltP is a structural gene for a carrier protein of an Na+-independent, binding protein-independent glutamate-aspartate transport system.

The magnetic transition from the ferro- to the para-magnetic state of manganese(II) phthalocyanine (C32H16N8Mn) has been observed by measurements of the magnetic susceptibility, the magnetization and the proton magnetic resonance in the low-temperature range. The positive Weiss constants were obtained from the static susceptibility measurements and the proton magnetic measurements. Moreover, the magnetic-field dependences of the experimental results were found in the low-temperature range. All of those findings confirm the ferromagnetic behavior of this substance in the lower-temperature region. From the measurements of the frequency shift in the resonant circuit of the proton magnetic resonance apparatus, the transition temperature was determined to be 8.6 K. A possible mechanism of long-range ordering was also discussed on the basis of the crystal structure of this substance.

The static magnetic susceptibility and the ESR spectra from 1.6 to 300 K have been measured on a powder sample of the titled free radical. The broad maximum in the susceptibility which indicates an antiferromagnetic interaction has been observed at 6.9 K. The broadening of the ESR absorption line and the shift of the g-value have been found in the temperature region below Tmax, in which the susceptibility reached its round maximum. There appeared anomalies in the slope of the susceptibility, the linewidth, and the g-value versus temperature curves in the vicinity of 1.7 K. These anomalies may imply a magnetic-phase transition from the short-range ordered state to the long-range ordered state at about 1.7 K. The existence of a ferromagnetic interaction between the magnetic chains in the triphenylverdazyl radical solid is discussed on the basis of the susceptibility, the spin distribution, and the crystal structure. It is understood qualitatively that the radical with a negative spin density has a latent ferromagnetic interaction in or between the magnetic chains, and that the obsrevation of this interaction greatly depends upon the molecular and crystal structure.

No abstract

Two human homeobox genes, HB9 and HLX, are expressed in hematopoietic progenitors and activated lymphocytes. They are implicated in the proliferation of hematopoietic progenitors in response to growth factors and the differentiation of hematopoietic progenitors to mature cell lineages. RNAs from bone marrow cells of patients with acute myeloid or lymphocytic leukemia have high levels of these two genes while similar RNAs from patients with chronic lymphocytic or myeloid leukemias have nearly normal levels. While the significance of these two genes in leukemogenesis is unknown, they are likely to regulate gene transcription during hematopoiesis and their dysregulation may have dire consequences for hematopoietic cells.

No abstract

The effect of in¯uenza vaccination on the occurrence and severity of in¯uenza virus infection in a population residing in nursing homes for the elderly was studied during an in¯uenza A (H3N2) epidemic in Japan. Of 22 462 individuals living in 301 welfare nursing homes, 10 739 received either one dose (2027 subjects) or two doses (8712 subjects) of inactivated, subunit trivalent in¯uenza vaccine. During the period Nov. 1998 to March 1999, there were 950 cases of in¯uenza infection diagnosed clinically, with virus isolation or serology. There were statistically signi®cantly fewer cases of in¯uenza, hospital admissions due to severe infection and deaths due to in¯uenza in the vaccinated cohort (256 cases, 32 hospital admissions, 1 death) than in the unvaccinated controls (694 cases, 150 hospital admissions, 5 deaths; reduction rates 59.8%, 76.9% and 79.1% respectively). Vaccination was almost equally effective in those who received one dose of vaccine and those who received two doses. No serious adverse reactions to vaccination were recorded. Thus in¯uenza vaccination is safe and effective in this population, and should be an integral part of the routine care of persons aged >65 years residing in nursing homes.