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1.
G. K. Innes B. J. Fuller K. E. F. Hobbs 《In vitro cellular & developmental biology. Plant》1988,24(2):126-132
Summary Rat hepatocytes were isolated and then maintained in serum-free cell culture medium for 24 h. The amount of malondialdehyde
(MDA) accumulated in the medium was assayed and used as a measure of lipid peroxidation. The acivity of lactate dehydrogenase
(LDH) and urea were measured in the medium and used as indicators of hepatocellular viability and function. The effects of
iron; desferrioxamine mesylate (Desferal), an iron chelator; and mannitol, a hydroxyl free radical scavenger were investigated.
The addition of iron, Fe2 resulted in a three-fold increase in the levels of MDA. Desferal inhibited the production of MDA and blocked the effect of
Fe2+. Neither iron nor Desferal had any effect on LDH or urea levels. Mannitol had no effect on MDA or urea production, but caused
a 4 to 8-fold increase in the LDH levels in the medium. The results show that iron is involved in the mechanism of lipid peroxidation
in hepatocyte cultures but suggest that as a pathologic event lipid peroxidation is not expressed in terms of viability during
the first 24 h of hepatocyte culture. 相似文献
2.
Various tests of function have been suggested for assessing hepatocytes recovered from cryopreservation. In this study we have investigated hepatocyte attachment during tissue culture and cellular density in order to assess function and compared them with two classical dye exposure tests. The ability of hepatocytes to exclude trypan blue dye (TB) and metabolize fluorescein diacetate (FDA) was demonstrated. In populations of freshly prepared hepatocytes 88.07% were able to exclude TB and 87.31% were able to metabolize FDA. However in populations of hepatocytes recovered after cryopreservation using 1.5 M dimethyl sulfoxide as cryoprotectant only 33.44% were able to exclude TB and 31.59% able to metabolize FDA. Both of these tests gave the same estimate of functional ability. Density gradient centrifugation of hepatocytes on Percoll 400 (Pharmacia, Uppsala, Sweden) separated two populations of hepatocytes; one (density ca.1.07 g/ml Percoll) in which most of the cells were able to exclude TB and the second (density ca. 1.02 g/ml Percoll) in which they were stained blue. The dense population was highly enriched in dye-excluding hepatocytes: freshly prepared hepatocytes, 92.4%, and cryopreserved hepatocytes, 88.66%. When samples of these cells (2 x 10(6) dye-excluding cells per dish) were tested for their ability to attach to tissue culture dishes only 17.28% of the cryopreserved hepatocytes were able to attach compared to 55.28% of the freshly prepared cells. We conclude that cryopreservation of hepatocytes produces a population of cells which are not metabolically identical to a population of freshly prepared hepatocytes even though they appear to have the same buoyant density and dye-excluding capabilities.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
4.
HAU3是寄主范围很广的放线菌噬菌体。Southern杂交实验表明,HAU3可以整合到吸水链霉菌应城变种10-22和变铅青链霉菌66的突变体ZX1的染色体中,形成溶原,其溶原菌自发释放HAU3,不受热激和紫外线照射的诱导。通过比较HAU3衍生噬粒pIJ8300的DNA酶切片段在加热前、后电泳带谱的区别,将HAU3的cos位点在pIJ8300的图谱上得到了定位。还利用Southern杂交的方法定位了HAU3与宿主形成溶原时附着位点(attP),并利用脉冲电泳技术定位了在变铅青链霉菌ZX7和吸水链霉菌应城变种10-22中形成溶原的附着位点(attB)。这些信息均有利于以HAU3为基础的载体的发展和优化。 相似文献
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6.
Emile CL. Marnette Harm Houweling Herman Van Dam Jan Willem Erisman 《Biogeochemistry》1993,23(2):119-144
The chemical composition of surface waters of two Dutch moorland pools and of incident precipitation, was monitored from 1982
to 1990. For this period, sulfur and water budgets were calculated using a hydrochemical model developed for well-mixed non-stratifying
lakes. Total atmospheric deposition of S decreased significantly after 1986 at both locations. A model describing the sulfur
budget in terms of input, output and reduction/oxidation processes predicted a fast decrease of pool water SO4
2− concentrations after a decrease of atmospheric input. However, SO4
2− concentrations in the surface water was lowered only slightly or remained constant. Apparently a source within the lake caused
the unexpectedly high SO4
2− concentrations. The possible supply of SO4
2− from the sediment through regulation by (K-)Al-SO4 containing minerals or desorption of SO4
2− from positively charged surfaces in the sediment was evaluated. Solubility calculations of pore water with respect to alunite,
basaluminite and jurbanite indicated that SO4
2− concentration was not regulated by these minerals. It is suggested here (1) that desorption of SO4
2− from peaty sediments may account for the estimated SO4
2− supply provided that the adsorption complex is periodically recharged by partial oxidation of the upper bottom sediments
and (2) that because of exposure of a part of the pool bottom to the atmosphere during dry summers and subsequent oxidation
of reduced S, the amount of SO4
2− may be provided which complements the decreasing depositional SO4
2− input. In future research these two mechanisms need to be investigated. 相似文献
7.
8.
Sulfate reduction and S-oxidation in a moorland pool sediment 总被引:3,自引:2,他引:1
In an oligotrophic moorland pool in The Netherlands, S cycling near the sediment/water boundary was investigated by measuring (1) SO4
2– reduction rates in the sediment, (2) depletion of SO4
2– in the overlying water column and (3) release of35S from the sediment into the water column. Two locations differing in sediment type (highly organic and sandy) were compared, with respect to reduction rates and depletion of SO4
2– in the overlying water.Sulfate reduction rates in sediments of an oligotrophic moorland pool were estimated by diagenetic modelling and whole core35SO4
2– injection. Rates of SO4
2– consumption in the overlying water were estimated by changes in SO4
2– concentration over time in in situ enclosures. Reduction rates ranged from 0.27–11.2 mmol m–2 d–1. Rates of SO4
2– uptake from the enclosed water column varied from –0.5, –0.3 mmol m–2 d–1 (November) to 0.43–1.81 mmol m–2 d–1 (July, August and April). Maximum rates of oxidation to SO4
2– in July 1990 estimated by combination of SO4
2– reduction rates and rates of in situ SO4
2– uptake in the enclosed water column were 10.3 and 10.5 mmol m–2 d–1 at an organic rich and at a sandy site respectively.Experiments with35S2– and35SO4
2– tracer suggested (1) a rapid formation of organically bound S from dissimilatory reduced SO4
2– and (2) the presence of mainly non SO4
2–-S derived from reduced S transported from the sediment into the overlying water. A35S2– tracer experiment showed that about 7% of35S2– injected at 1 cm depth in a sediment core was recovered in the overlying water column.Sulfate reduction rates in sediments with higher volumetric mass fraction of organic matter did not significantly differ from those in sediments with a lower mass fraction of organic matter.Corresponding author 相似文献
9.
ATM requirement in gene expression responses to ionizing radiation in human lymphoblasts and fibroblasts 总被引:3,自引:0,他引:3
Innes CL Heinloth AN Flores KG Sieber SO Deming PB Bushel PR Kaufmann WK Paules RS 《Molecular cancer research : MCR》2006,4(3):197-207
The heritable disorder ataxia telangiectasia (AT) is caused by mutations in the AT-mutated (ATM) gene with manifestations that include predisposition to lymphoproliferative cancers and hypersensitivity to ionizing radiation (IR). We investigated gene expression changes in response to IR in human lymphoblasts and fibroblasts from seven normal and seven AT-affected individuals. Both cell types displayed ATM-dependent gene expression changes after IR, with some responses shared and some responses varying with cell type and dose. Interestingly, after 5 Gy IR, lymphoblasts displayed ATM-independent responses not seen in the fibroblasts at this dose, which likely reflect signaling through ATM-related kinases, e.g., ATR, in the absence of ATM function. 相似文献
10.