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11.
To evaluate the influence of overwintering individuals of zooplankton on spring zooplankton communities, the dynamics of zooplankton
communities with or without overwintering individuals were observed in experimental ponds from fall to spring. An insecticide,
carbaryl, was used to regulate the overwintering individuals. In ponds which received insecticide applications in November
or January, all cladoceran and rotiferan species were eliminated by the treatments and did not reappear until late March or
early April, even when the chemical disappeared rapidly. The low water temperature may delayed the establishment of the populations
from resting eggs. In these ponds, populations of various cladoceran and rotiferan species, which seemed to be originated
from resting eggs, were built up in the spring. In control ponds,Daphnia ambigua orD. longispina overwintered as juveniles and adults and established a large spring population earlier than other cladocerans and rotifers
overwintering as resting eggs. The latter zooplankters did not increase in the spring probably because their growth was suppressed
by the precedingDaphnia species through competition. In nature, even if the number of overwintering individuals is small, they may have a potential
to build up a large population earlier than the individuals hatching from resting eggs. As a result, the species which have
overwintered as individuals seem to predominate in the spring and have a large influence on the spring zooplankton community. 相似文献
12.
Vibrio hollisae strains isolated recently from patients in various locations were examined for the presence of the thermostable direct hemolysin gene (tdh) using nucleic acid hybridization and polymerase chain reaction assays. The results were consistent with the previous finding that all strains of V. hollisae carry the tdh gene. In contrast, the tdh gene has been detected in a minority of strains for other Vibrio species (V. parahaemolyticus, V. cholerae non-O1, and V. mimicus). Detailed phylogenetic analysis showed that the tdh genes of the non-V. hollisae species were very closely related to each other and that the tdh gene of V. hollisae was distantly related to the tdh genes of the non-V. hollisae species. These results and the proposed insertion sequence-mediated tdh transfer mechanism suggest that the tdh gene may have been maintained stably in V. hollisae and that the tdh genes of the non-V. hollisae species may have been involved in recent horizontal transfer. 相似文献
13.
Efficiency of serum copper/zinc ratio for differential diagnosis of patients with and without lung cancer 总被引:1,自引:0,他引:1
Tsunehiro Oyama Koji Matsuno Toshihiro Kawamoto Tetsuya Mitsudomi Takayuki Shirakusa Yasushi Kodama 《Biological trace element research》1994,42(2):115-127
We examined serum copper (Cu), serum zinc (Zn), and the serum copper/zinc ratio (Cu/Zn) in 162 patients. All of them were
seen to have an abnormal shadow in the chest X-ray films, that is, 109 patients with lung cancer (LC) and 53 patients with
no lung cancer (NLC). The mean Cu and Cu/Zn in LC patients were significantly higher than those in NLC patients (p<0.05). In LC patients, Cu and Cu/Zn were higher and Zn was lower in advanced tumors than early ones. There was a significantly
clear relation between Cu or Cu/Zn and the tumor (T) stages. When the relative risk (RR) of LC was estimated, it was seen
that the higher Cu and Cu/Zn became, the higher RR became. Furthermore, we showed the sensitivity of the receiver operator
characteristic of the test (ROC) curve for Cu, Cu/Zn, and carcinoembryonic antigen (CEA) to diagnose LC, as explained in a
paragraph of methods.The determinations of Cu, Zn, and Cu/Zn are simple and inexpensive. They also appear to have a great diagnostic value in determining the local invasion of LC and as a screening test in the
high-risk patients for LC. 相似文献
14.
Takayuki Nakatsubo 《Ecological Research》1994,9(3):245-250
In order to evaluate the importance of growth of mosses in controlling evaporative water loss, the evaporation rates of some
subalpine moss species of various growth forms were compared with each other. The growth forms of the xerophytic species examined
were large cushion and compact mat, while those of the mesophytic species in the coniferous forest floor were smooth mat,
weft and tall turf. The evaporation rate per moss dry weight (Ew) was much smaller in the xerophytic species than in the mesophytic
species. However, the evaporation rate per basal area of moss colony (Ea) was not necessarily smaller in the xerophytic species.
The relation between Ea and dry weight per basal area of the colony (Wa) had a close correlation with the growth form. It
was concluded that the difference in the evaporation rate per weight between the exerophytic species and the mesophytic species
was largely due to the difference in Wa, and that the growth forms of the xerophytic species were suitable for increasing
Wa without increasing surface roughness. 相似文献
15.
Shuhei Takatsuka Takeshi Kubota Yuta Kurashina Sho Kurihara Motoki Hirabayashi Masato Fujioka Hirotaka James Okano Hiroaki Onoe 《Biotechnology and bioengineering》2023,120(8):2371-2377
Adeno-associated virus (AAV)-based gene therapy holds promise as a fundamental treatment for genetic disorders. For clinical applications, it is necessary to control AAV release timing to avoid an immune response to AAV. Here we propose an ultrasound (US)-triggered on-demand AAV release system using alginate hydrogel microbeads (AHMs) with a release enhancer. By using a centrifuge-based microdroplet shooting device, the AHMs encapsulating AAV with tungsten microparticles (W-MPs) are fabricated. Since W-MPs work as release enhancers, the AHMs have high sensitivity to the US with localized variation in acoustic impedance for improving the release of AAV. Furthermore, AHMs were coated with poly-l -lysine (PLL) to adjust the release of AAV. By applying US to the AAV encapsulating AHMs with W-MPs, the AAV was released on demand, and gene transfection to cells by AAV was confirmed without loss of AAV activity. This proposed US-triggered AAV release system expands methodological possibilities in gene therapy. 相似文献
16.
Parietochloris incisa comb. nov. (Trebouxiophyceae, Chlorophyta) 总被引:3,自引:0,他引:3
Shin Watanabe Seishiro Hirabayashi Sammy Boussiba Zvi Cohen Avigad Vonshak Amos Richmond 《Phycological Research》1996,44(2):107-108
A coccoid green alga, Myrmecia incisa Reisigl, was isolated from the soil of Mt Tateyama, Japan. Electronmicroscopy revealed that the organism has pyrenoids sparsely covered with starch segments and traversed by many parallel thylakoid membranes, and zoo-spores with counterclockwise basal body orientation. Due to the presence of these features, we have proposed a reclassification of M. incisa into the genus Parietochloris, Trebouxiophyceae. 相似文献
17.
18.
Y Kasahara A Wakata Y Nakai K Yuno D Miura K Yagi K Hirabayashi T Makita 《Mutation research》1992,278(2-3):145-151
The induction of micronuclei by methotrexate (MTX) was examined in two laboratories using mouse peripheral blood reticulocytes. MTX was a weak inducer in the micronucleus test using bone marrow cells and single treatments, and was one of the few chemicals showing a multiple-treatment effect (CSGMT/JEMS.MMS, 1990). In our preliminary experiments, the ratio of reticulocytes to total erythrocytes decreased greatly after a single treatment with MTX at 100 mg/kg, so lower dose levels of MTX were selected to carry out the micronucleus test in peripheral blood. Full-scale tests were performed at dose levels of 0, 10, 20, 40, and 80 mg/kg, with five sampling times of 0, 24, 48, 72, and 96 h. Frequencies of micronucleated reticulocytes (MNRETs) increased dose-dependently at 72 h, to a maximum of approximately 1%; some preparations obtained from the animals at higher doses could not be examined because the ratio of reticulocytes to total erythrocytes had decreased severely. At doses of 0.5-4.0 mg/kg, the effect of multiple treatments vs. single treatments was not clear, nor was the maximum level of response much different. Since MTX induced a clear positive response in peripheral blood reticulocytes after a single treatment, the reticulocytes in peripheral blood seem a more sensitive target. 相似文献
19.
20.
M Ito M Baba S Mori K Hirabayashi A Sato S Shigeta E De Clercq 《Biochemical and biophysical research communications》1990,166(3):1095-1101
Tumor necrosis factor alpha (TNF-alpha) completely reverses the activity of azidothymidine (AZT) against human immunodeficiency virus type 1 (HIV-1) in MOLT-4 cell cultures. The 50% effective concentration of AZT, required to protect MOLT-4 cells against the cytopathic effect of HIV-1, increased from 5.8 nM in the absence of TNF-alpha to greater than 125 microM in the presence of TNF-alpha (100 U/ml). TNF-alpha also antagonized the anti-HIV-1 activity of dideoxycytidine but did not markedly affect the anti-HIV-1 activity of dextran sulfate. The intracellular phosphorylation pattern of AZT was not changed upon the presence of TNF-alpha. 相似文献