MPTP in mice: treatment, distribution and possible source of contamination

Mice were treated daily with [3H]MPTP (30 mg/kg, 1 uCi, s.c.) for 1, 3, and 10 days to determine the fate and localization of tritiated compounds. An untreated mouse was housed either in the same cage ("cage-mate control") or in an adjacent cage separated by mesh-wire ("near-neighbor control"). The radioactivity measured in blood, brain, liver, and remaining body of [3H]MPTP-treated mice was dependent on the total dose of the drug the animals received and did not vary with the type of tissue analyzed. Significant amounts of radioactivity were found in the tissues of the "cage-mate control" mice, but not of the "near-neighbor control" mice. The route of transmission appears to be through the urine, as the urine of [3H]MPTP-treated mice was highly radioactive after the drug injection. Only traces of radioactivity were found in their feces and there was no increase in the background radiation in the environment of the cages, indicating that the tritiated compounds were not exhaled. Proper disposal of urinary products of MPTP-treated animals is therefore necessary to reduce the risk of possible drug contamination in humans.     

Role of cell-mediated immunity in the resistance to experimental sporotrichosis in mice

The in vitro activity of several new imidazoles, cloconazole, sulconazole, butoconazole, isoconazole and fenticonazole, were compared with those of amphothericin B, flucytosine, and three azoles: econazole, miconazole and ketoconazole against isolates of pathogenic Candida. A total of 186 clinical isolates of 10 species of the genus Candida and two culture collection strains were tested by an agar-dilution technique. Isoconazole was the most active azole, followed by butoconazole and sulconazole. Differences between some of the species in their susceptibility to the antifungal agents were noted. Sulconazole and cloconazole had the highest activity in vitro against 106 isolates of C. albicans. Butoconazole and isoconazole were also very active against isolates of C. albicans, and were the most active azole compounds against 80 isolates of Candida spp.     

New Agrostis from the California coast

Agrostis clivicola, A. clivicola var.punta-reyesensis andA. blasdalei var.marinensis are described from the California coast. A key distinguishes these from other species of similar habit and habitat.     

DETERMINATION OF GUSTATORY SUCROSE THRESHOLD IN WATER BY USE OF A LINEAR SUCROSE GRADIENT

A novel experimental method was developed which allows the determination of the threshold concentration of sucrose by use of a linear sucrose gradient in water. With this method a continuous tasting of the test-liquid is possible. A panel of 15 persons experienced in taste-testing was used. Three gradients of different steepness were applied: 0 to 1.5% (w/w) sucrose in 2 min (I), 3 min (II) and 4 min (III). The results of the new method were compared with those of the standard method (DIN). With gradients I and II we found values which were significantly higher than those of the standard method (I: 0.49% (w/w); II: 0.46% (w/w); DIN: 0.31% (w/w)), whereas with gradient III the same threshold value was found as with the DIN-Method (III: 0.32% (w/w)).     

应用气-质联用仪测定三种螺旋藻中的甾醇成分

应用GLC/MS联用仪对室内培养的钝顶螺旋藻(Spirulina platensis (Nordstedt) Geitler)、极大螺旋藻(S.maxima (Stechell & Gardiner) Geitler)和盐泽螺旋藻(S.subsalsa Oerst)的甾醇成分进行了测定。从钝顶螺旋藻和盐泽螺旋藻中共分出11个相同的甾醇组分:胆甾醇、胆甾烷醇、芸苔甾醇、麦角甾醇、海绵甾醇、菜子甾醇、豆甾醇、24-乙基-Δ~(5,7,22)-胆甾醇、β-谷甾醇、异岩藻甾醇和4α,23,24-三甲基Δ~(5,22)-胆甾醇;从极大螺旋藻中只分离出8个甾醇组分。其中胆甾醇含量最高。4α,23,24-三甲基-Δ~(5,22)-胆甾醇为蓝藻中首次报导。     

The Aedes aegypti genome: complexity and organization.

We describe the use of DNA reassociation kinetics to determine the total genome size and complexity together with the individual complexity and copy number of the single copy, middle repetitive and highly repeated DNA fractions of cell line and larval DNA from the mosquito, Aedes aegypti. The genome of Ae. aegypti is both large and complex, being one third the size of the human genome, and exhibits a short period interspersed repeat pattern. The implications of patterns of sequence arrangement and genome complexities for experiments aimed at isolating specific classes of DNA sequences, such as mobile genetic elements, are discussed.     

Organization of a family of highly repetitive sequences within the human genome

Recombinant clones containing the highly repetitive human DNA sequence approximately 340 base-pairs in length obtained after EcoRI digestion (αRI-DNA) were cloned in plasmid pAT153. Two clones contained a single copy of the αRI-DNA sequence, and the third had an insert with two copies of the sequence in tandem. When radioactive recombinant DNA was hybridized to total human DNA partially digested with EcoRI, a series of multiple bands was obtained up to 22 repeats in length, demonstrating that the αRI-DNA sequences occur in tandem arrays in the genomic DNA. A reassociation analysis using isolated insert DNA from one of the recombinant clones showed that the family of sequences is repeated 22,000 times in the human genome. Clones containing the αRI-DNA sequence were also isolated from a library of human genomic DNA in bacteriophage λ. Using these clones it was shown that, in at least some cases, the repetitive element is bounded by DNA less abundant than the αRI sequence.