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1.
2.
The effect of long-term (77 day) exposure of carp Cyprinus carpio to low concentrations of waterborne iron (1 mg Fe-dextran l−1 ) on accumulation and cellular distribution of iron in the liver was assessed using Perl's staining and histological observations and morphometric measurements. Accumulation of iron in the liver occurred after 14 days of exposure, when the majority of the iron was found in the sinusoidal endothelium with lower amounts in the cytoplasm and nuclei of hepatocytes. Upon further treatment the iron was predominantly distributed in the cytoplasm of the hepatocytes either as granules or diffusive iron and in macrophages. 相似文献
3.
Mehmet Yaar can 《American journal of physical anthropology》1989,78(1):3-8
This study analyzes and compares the dental size variation and sexual dimorphism of the Highland Beach Mound people, a late southeastern prehistoric aboriginal Florida population (ca. 800-1200 AD) with a somewhat earlier midwestern group (ca. 200-800 AD) and an Archaic sample (ca. 4160-2558 BC). The lengths and breadths of maxillary and mandibular permanent teeth of 99 individuals were measured, and crown surface areas were calculated for the molars. Results indicated that there was little sexual dimorphism. Only the mesiodistal dimensions of the upper P2 and lower C were significantly different at the P less than 0.05 level. In terms of dental size, what appears to be a chronologically based reduction in most points of comparison was seen in all three groups, with the exception of the molars, which were larger in the Highland Beach sample than in the earlier Schultz Mound. 相似文献
4.
Histiobalantium sp. was found regularly in the pelagic zoneof Lake Constance, FRG, over five annual cycles. Maxima of upto 6400 cells l1 were recorded in late summer, with similarnumbers in the 08 and 820 m depth intervals. Onan annual average, the population accounted for 1017%of the total biomass of planktonic ciliates. In the laboratory,Histiobalantium grew well on a diet of the cryptophyte Rhodomonassp. Maximum growth rates obtained in batch cultures were 0.21and 0.33 day11 at 9 and 18°C, respectively. In situexperiments using diffusion chambers yielded positive growthrates in autumn and winter. The highest values recorded at theambient temperatures 5, 14 and 17°C were 0.17, 0.32 and0.40 day1, respectively. Comparing these results withthe different seasonal distributions and higher measured growthrates of other ciliates from Lake Constance, we conclude thatHistiobalantium is a superior competitor at relatively low algalfood concentrations.
2Present address: Fisheries & Oceans Canada, 4160 MarineDrive, West Vancouver, BC, V7V 1N6, Canada 相似文献
5.
Garðar Guðmundsson 《Vegetation History and Archaeobotany》1996,5(1-2):13-23
Lyme-grass (Elymus arenarius L.) was harvested and processed for human consumption along the southern coast of Iceland until the beginning of this century.
The origin of this exploitation is not known, but lyme-grass may have been gathered for this purpose already in the Viking
Age. The system of processing lyme-grass is complex, and special implements and facilities are needed. The method is similar
to traditional processing methods for cereals. Extensive research on Icelandic ethnographic observations was undertaken to
establish the exact methods and sequence of operations that was involved. On the basis of this, a set of archaeological experiments
was performed to test the viability of the processing techniques outlined in the written records. A model describing the harvesting
and processing of lyme-grass is presented. 相似文献
6.
Darja Barlič Maganja Borut Štrukelj Jože Pungerčar Franc Gubenšek Vito Turk Igor Kregar 《Plant molecular biology》1992,20(2):311-313
A genomic DNA clone encoding an aspartic proteinase inhibitor of potato was isolated from a lambda EMBL3 phage library using the aspartic proteinase inhibitor cDNA as a hybridization probe. The gene has all characteristic sequences normally found in eucaryotic genes. Typical CAAT and TATA box sequences were found in the 5-upstream region. In this part are also two putative regulatory AGGA box sequences located. In the genomic sequence there are no intron sequences interrupting the coding region. An open reading frame of the gene encodes a precursor protein of 217 amino acids which shows high percent identity with the aspartic proteinase inhibitor cDNA. 相似文献
7.
K U?ar 《Biochemical and biophysical research communications》1991,177(1):545-550
B16-C3 murine melanoma, A375P human melanotic melanoma, and C32 human amelanotic melanoma cells were incubated in the presence of (0-4 mM) H2-antagonists, ranitidine and cimetidine. Cell proliferation, tyrosinase activity and melanin content were monitored. H2-antagonists stimulated tyrosinase activity and melanin accumulation in B16-C3 cells in a dose- and time-dependent manner. Stimulation of enzyme activity and pigment production was accompanied by inhibition of cellular proliferation in B16-C3 cells. The inhibitory concentration of cimetidine was approximately 2-fold higher than that of ranitidine. H2-antagonists failed to stimulate melanogenesis in A375P or C32 cells, but inhibited cellular proliferation in both cell lines. These results are the first demonstration of H2-antagonist induced phenotypic changes in malignant melanoma cells in vitro, and represent a novel mechanism for the previously described in vivo antitumor effects of these agents. 相似文献
8.
9.
The effect of cyclic anaerobic–aerobic conditions on the biodegradative capability of the mixed microbial culture for the
azo dye Remazol Brilliant Violet 5R (RBV-5R) was investigated in the sequencing batch reactor (SBR) fed with a synthetic textile
wastewater. The SBR had a 12-h cycle time with anaerobic–aerobic periods of 3/9, 6/6 and 9/3 h. General SBR performance was
assessed by measurement of catabolic enzymes (catechol 2,3-dioxygenase, azo reductase), chemical oxygen demand (COD), color
and amount of aromatic amines. In this study, under steady-state conditions, the anaerobic period of the cyclic SBR was found
to allow the reductive decolorization of azo dye. Longer anaerobic periods resulted in higher color removal efficiencies,
approximately 71% for the 3-h, 87% for 6-h and 92% for the 9-h duration. Total COD removal efficiencies were over 84% under
each of the cyclic conditions and increased as the length of the anaerobic period was increased; however, the highest color
removal rate was attained for the cycle with the shortest anaerobic period of 3 h. During the decolorization of RBV-5R, two
sulfonated aromatic amines (benzene based and naphthalene based) were formed. Additionally, anaerobic azo reductase enzyme
was found to be positively affected with the increasing duration of the anaerobic period; however; it was vice versa for the
aerobic catechol 2,3-dioxygenase (C23DO) enzyme. 相似文献
10.
Nitric oxide plays a central role in determining lateral root development in tomato 总被引:38,自引:0,他引:38
Nitric oxide (NO) is a bioactive molecule that functions in numerous physiological processes in plants, most of them involving cross-talk with traditional phytohormones. Auxin is the main hormone that regulates root system architecture. In this communication we report that NO promotes lateral root (LR) development, an auxin-dependent process. Application of the NO donor sodium nitroprusside (SNP) to tomato (Lycopersicon esculentum Mill.) seedlings induced LR emergence and elongation in a dose-dependent manner, while primary root (PR) growth was diminished. The effect is specific for NO since the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO) blocked the action of SNP. Depletion of endogenous NO with CPTIO resulted in the complete abolition of LR emergence and a 40% increase in PR length, confirming a physiological role for NO in the regulation of root system growth and development. Detection of endogenous NO by the specific probe 4,5-diaminofluorescein diacetate (DAF-2 DA) revealed that the NO signal was specifically located in LR primordia during all stages of their development. In another set of experiments, SNP was able to promote LR development in auxin-depleted seedlings treated with the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA). Moreover, it was found that LR formation induced by the synthetic auxin 1-naphthylacetic acid (NAA) was prevented by CPTIO in a dose-dependent manner. All together, these results suggest a novel role for NO in the regulation of LR development, probably operating in the auxin signaling transduction pathway.Abbreviations
CPTIO
2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide
-
DAF-2 DA
4,5-Diaminofluorescein diacetate
-
LR
Lateral root
-
NAA
1-Naphthylacetic acid
-
NO
Nitric oxide
-
NPA
N-1-Naphthylphthalamic acid
-
PR
Primary root
-
SNP
Sodium nitroprusside 相似文献