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1.
Maria João Feio Trefor B. Reynoldson Verónica Ferreira Manuel Augusto S. Graça 《Hydrobiologia》2007,579(1):55-68
We sampled macroinvertebrates at 75 locations in the Mondego river catchment, Central Portugal, and developed a predictive
model for water quality assessment of this basin, based on the Reference Condition Approach. Sampling was done from June to
September 2001. Fifty-five sites were identified as “Reference sites” and 20 sites were used as “Test sites” to test the model.
At each site we also measured 40 habitat variables to characterize water physics and chemistry, habitat type, land use, stream
hydrology and geographic location. Macroinvertebrates were generally identified to species or genus level; a total of 207
taxa were found. By Unweighted Pair Group Method with Arithmetic mean (UPGMA) clustering and analysis of species contribution
to similarities percentage (SIMPER), two groups of reference sites were established. Using Discriminant Analysis (stepwise
forward), four variables correctly predicted 78% of the reference sites to the appropriate group: stream order, pool quality,
substrate quality and current velocity. Test sites’ environmental quality was established from their relative distance to
reference sites, in MDS ordination space, using a series of bands (BEAST methodology). The model performed well at upstream
sites, but at downstream sites it was compromised by the lack of reference sites. As with the English RIVPACS predictive model,
the Mondego model should be continually improved with the addition of new reference sites. The adaptation of the Mondego model
methodology to the Water Framework Directive is possible and would consist mainly of the integration of the WFD typology and
increasing the number of ellipses that define quality bands.
Handling editor: K. Martens 相似文献
2.
The effect of tin and lead on levels of essential metals (Zn, Cu, Ca, Fe) in rabbit tissues was compared in relation to the route of administration. Animals received intraperitoneally, or per os, SnCl2 (2 mg Sn/kg) or Pb(CH3COO)2 (3.5 mg Pb/kg) every day for 5 d or for 1 mo. Copper, zinc, iron, and calcium were determined by AAS in the liver, kidneys, spleen, brain, bone marrow, and blood; lead and tin concentration were measured in the blood of animals. Tin and lead administered per os caused either no changes or the decreased concentration of endogenous metals in several tissues. The other route of administration (ip) of both metals generally contributed to the increased storage of essential elements. Blood tin levels of tin treated animals were only about less than or equal to 1/10 of blood lead concentrations of rabbits exposed to lead. 相似文献
3.
G. Egea J. M. Ureña X. Graña J. Marsal J. Carreras F. Climent 《Histochemistry and cell biology》1992,97(3):269-275
Summary We have previously reported (Ureña et al. Eur. J. Cell Biol. 1990) that in skeletal muscle, type MM phosphoglycerate mutase isozyme is present in the nucleus as well as in the cytosol. To determine whether type BB phosphoglycerate mutase isozyme is also present in nucleus, the subcellular location of this isozyme was studied in different rat tissues by cell fractionation and immunogold techniques. With the aid of high affinity-purified anti-phosphoglycerate mutase BB isozyme antibodies, the isozyme was located in the nucleus of neuronal, astroglial and liver cells but not in the nucleus of oligodendroglial and endothelial cells. Biochemical studies on purified nuclear fractions also demonstrated the presence of phosphoglycerate mutase activity in the nucleus. Both immunocytochemical and biochemical techniques showed that nuclear phosphoglycerate mutase-specific activity depended on the type of cell.Abbreviations PGAM
phosphoglycerate mutase
- PGAM-M(M)
muscle specific subunit (isozyme) of PGAM
- PGAM-B(B)
brain type subunit (isozyme) of PGAM
- ssDNA
single stranded DNA
- PBS
0.001 M phosphate buffer, pH 7.4, containing 0.15 M NaCl
- kDa
kilodalton 相似文献
4.
CTP-dependent lipid kinases of yeast 总被引:1,自引:0,他引:1
A Szkopińska L Nowak E Swiezewska G Palamarczyk 《Archives of biochemistry and biophysics》1988,266(1):124-131
Membrane fractions from yeast Saccharomyces cerevisiae catalyzed a transfer of gamma-phosphate from [gamma-32P]CTP into membranous lipids. Phosphorylated compounds were identified as phosphatidic acid and dolichyl phosphate (DolP). The membrane fraction also catalyzed phosphorylation of the exogenous dolichol. The activity of the phosphorylating enzymes could be modified by the yeast growing conditions; i.e., the enzyme from yeast grown aerobically favored the synthesis of phosphatidate over dolichyl phosphate in the ratio of 3:1, whereas the membrane fraction from anaerobically grown yeast synthesized PA and DolP in the ratio of 0.5:1. The activity of the phosphorylating enzymes could also be modified by divalent cations and the concentration of detergents. Phosphorylation of lipids does not occur in the presence of [gamma-32P]ATP and is not influenced by the presence of UTP or GTP. This result points to the specific role of CTP as a gamma-phosphate donor for the synthesis of phosphatidate and dolichyl phosphates in the yeast system. 相似文献
5.
Andrzej Paszczyński Jan Fiedurek Zdzislaw Ilczuk Grażyna Ginalska 《Applied microbiology and biotechnology》1985,22(6):434-437
Summary Two proteases from Aspergillus niger C post-culture medium were isolated by fractionation on a DEAE-sepharose column and ultrafiltration. The four fractions of glucoamylase activity (GA1, GA2, GA3 and GA4) present in the medium showed different susceptibility to the influence of proteases. The effects of proteases on the different glucoamylase fractions during the growth of the fungus are demonstrated. The activity was found to decrease at the beginning of the culture, but by its end there was a stimulation of GA4 glucoamylase. After treating GA2 and GA3 with protease II, a new additional fraction of glucoamylase was detected. 相似文献
6.
7.
The effect of castanospermine on the oligosaccharide structures of glycoproteins from lymphoma cell lines. 总被引:2,自引:0,他引:2 下载免费PDF全文
The effect of castanospermine on the processing of N-linked oligosaccharides was examined in the parent mouse lymphoma cell line and in a mutant cell line that lacks glucosidase II. When the parent cell line was grown in the presence of castanospermine at 100 micrograms/ml, glucose-containing high-mannose oligosaccharides were obtained that were not found in the absence of inhibitor. These oligosaccharides bound tightly to concanavalin A-Sepharose and were eluted in the same position as oligosaccharides from the mutant cells grown in the absence or presence of the alkaloid. The castanospermine-induced oligosaccharides were characterized by gel filtration on Bio-Gel P-4, by h.p.l.c. analysis, by enzymic digestions and by methylation analysis of [3H]mannose-labelled and [3H]galactose-labelled oligosaccharides. The major oligosaccharide released by endoglucosaminidase H in either parent or mutant cells grown in castanospermine was a Glc3Man7GlcNAc, with smaller amounts of Glc3Man8GlcNAc and Glc3Man9GlcNAc. On the other hand, in the absence of castanospermine the mutant produces mostly Glc2Man7GlcNAc. In addition to the above oligosaccharides, castanospermine stimulated the formation of an endoglucosaminidase H-resistant oligosaccharide in both cell lines. This oligosaccharide was characterized as a Glc2Man5GlcNAc2 (i.e., Glc(1,2)Glc(1,3)Man(1,2)Man(1,2)Man(1,3)[Man(1,6)]Man-GlcNAc-GlcNAc). Castanospermine was tested directly on glucosidase I and glucosidase II in lymphoma cell extracts by using [Glc-3H]Glc3Man9GlcNAc and [Glc-3H]Glc2Man9GlcNAc as substrates. Castanospermine was a potent inhibitor of both activities, but glucosidase I appeared to be more sensitive to inhibition. 相似文献
8.
Summary A new form of ectodermal dysplasia was observed in two siblings, offspring of healthy non-consanguineous parents. The main findings in both children are: hypodontia, abnormally shaped teeth, scalp hypotrichosis, pili annulati, follicular hyperkeratosis on the trunk and limbs, intensified delineation and reticular hyperpigmentation of the nape, and hyperopia; one of the siblings also has astigmatism. As both patients have normal nails and are euhidrotic, this is an ectodermal dysplasia of the pilodental subgroup. The cause is probably genetic and autosomal-recessive inheritance is most likely. 相似文献
9.
O I Gimautdinova I I Gorshkova G G Karpova I V Kutiavin D M Gra?fer 《Molekuliarnaia biologiia》1984,18(5):1419-1423
Alkylation of E. coli tRNAPhe with 4-(N-2-chloroethyl-N-methylamino) benzyl-5'-phosphamide of oligonucleotide d(pAACCA) was studied. G24 residue located near the sequence C17GGDA21 partially complementary to the oligonucleotide moiety of the reagent was shown to be alkylated. Oligonucleotide d(pAACCA) inhibited the alkylation. Association constant of oligonucleotide derivative with tRNAPhe (10(3) M-1) was evaluated from the dependence of the extent of tRNA modification on the concentration of the reagent. The reported method for selective alkylation of tRNA may be used for preparing photoaffinity derivatives of tRNA bearing an arylazidogroups in desired position. 相似文献
10.
Abundance and biomass estimates of the benthic fauna in Admiralty Bay,King George Island,South Shetland Islands 总被引:9,自引:6,他引:3
Summary Quantitative benthic samples were collected along three transects in Admiralty Bay, King George Island, South Shetlands. At each of a total of 18 stations, between 15 and 250 m depth, we took 3 replicate samples with a van Veen grab. Animals collected were classed into major groups. Abundance and biomass per m2 was calculated for each sampling site. Considerable population densities and high biomass values were found. Most abundant groups were Bivalvia, Polychaeta and Amphipoda, whereas the largest part of the biomass was due to Ascidiacea, Ophiuroidea, Echinoidea, Polychaeta and Bivalvia. The maximum abundance recorded was 36,000 ind m-2 while the average was approximately 6500 ind m-2. Maximum biomass was over 2400 g m-2 with an average of ca. 700 g m-2. The contribution to the total biomass by groups such as the Oligochaeta, Cumacea and Tanaidacea was higher in the inner shallow part of Admiralty Bay (Ezcurra Inlet) than in the deeper areas of the bay. Our results confirm the reports on an unusually high density and biomass of the Antarctic sublittoral benthic fauna. Sessile suspension feeders belonging to the Bivalvia, Ascidiacea, sedentary Polychaeta, and vagile scavengers of the Ophiuroidea, Amphipoda and errant Polychaeta are the most significant groups in the Antarctic Ecosystem. The total benthic biomass in Admiralty Bay, based on the present preliminary quantitative data, was estimated to be over 600,000 t. This value is probably still an underestimate. 相似文献