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1.
Wester RC Hartway T Maibach HI Schell MJ Northington DJ Culver BD Strong PL 《Biological trace element research》1998,66(1-3):111-120
Literature from the first half of this century reports concern for toxicity from topical use of boric acid, but assessment
of percutaneous absorption has been impaired by lack of analytical sensitivity. Analytical methods in this study included
inductively coupled plasmamass spectrometry which now allows quantitation of percutaneous absorption of10B in10B-enriched boric acid, borax and disodium octaborate tetrahydrate (DOT) in biological matrices.
In vitro human skin percent doses of boric acid absorbed were 1.2 for a 0.05% solution, 0.28 for a 0.5% solution, and 0.70
for a 5.0% solution. These absorption amounts translated into flux values of, respectively, 0.25, 0.58, and 14.58 μg/cm2/h, and permeability constants (K
p
) of 5.0 x 10-4, 1.2 x 10-4, and 2.9 x 10-4 cm/h for the 0.05%, 0.5%, and 5.0% solutions. The above in vitro doses were at infinite, 1000 μL/cm2 volume. At 2 μL/cm2 (the in vivo dosing volume), flux decreased some 200-fold to 0.07 μg/cm2/h andK
p
of 1.4 x 10-6 cm/h, while percent dose absorbed was 1.75%.
Borax dosed at 5.0%/1000 μL/cm2 had 0.41 percent dose absorbed, flux at 8.5 μg/cm2/h, andK
p
was 1.7 x 10-4 cm/h. Disodium octaborate tetrahydrate (DOT) dosed at 10%/1000 μL/cm2 was 0.19 percent dose absorbed, flux at 7.9 μg/cm2/h, andK
p
was 0.8 x ICH cm/h. These in vitro results from infinite doses (1000 μL/cm2) were a 1000-fold greater than those obtained in the companion in vivo study. The results from the finite (2 μL/cm2) dosing were closer (10-fold difference) to the in vivo results. General application of infinite dose percutaneous absorption
values for risk assessment is questioned by these results. 相似文献
2.
Various measurements of microbial productivity in streambed pebble biofilms were analyzed almost monthly for 1 year to quantify the importance of primary production as an autochthonous source of organic matter utilized to support heterotrophic bacterial production in the dynamic food web within this natural microbial habitat. Bacterial density varied from 0.3 × 108 to 1.4 × 108 cells cm−2, and chlorophyll a concentration ranged from 0.7 to 25.9 μg cm−2, with no coupled oscillation between seasonal changes in these two parameters. In bottle incubation experiments, the instantaneous bacterial growth rate of bacteria was significantly correlated with their production rate [measured by frequency of dividing cells (FDC)] as follows: ln μ = 0.138FDC − 3.003 (n = 15, r
2 = 0.445, p < 0.001). FDC values in the pebble biofilms increased with fluctuations during the study period, ranging from 3.6% to 9.2%. Bacterial production rates largely fluctuated between 0.15 to 0.92 μg C cm−2 h−1, and its seasonal pattern was similar to that of bacterial density. Net primary production measured between May 2002 to November 2002 attained minimum level (0.5 μg C cm−2 h−1) in June and maximum level (1.9 μg C cm−2 h−1) in August. Percentages of bacterial production to net primary production ranged between 21% and 120%. Because this ratio extends both below and above 100% for these parameters, it is likely that both autochthonous and allochthonous supplies of organic matter are important for production of bacteria in the pebble biofilms that develop in rapidly flowing fresh water streams. 相似文献
3.
Cyanobacteria were a major constituent of phototrophic communities in the lakes, ponds and streams of Bylot Island, in the
Canadian high Arctic. The waters spanned a range of temperatures (1.8–16.8°C in late July), pH regimes (6.2–9.2) and conductivities
(1.5–1700 μS cm−1) but nutrient concentrations were consistently low (< 1 μg dissolved reactive P l−1 at all sites; < 10 μg NO3-N l−1 at most sites). Picoplanktonic species (Synechococcus spp.) were often the numerical dominants in the plankton, and periphytic filamentous species (Oscillatoriaceae) commonly
formed thick (5–50 mm) benthic mats. Bloom-forming species of cyanobacteria were either absent or poorly represented even
in Chla-rich ponds. The total community biomass ranged from 0.1 to 29.8 μg Chla l−1 in the plankton and from 1.1 to 34.8 μg Chla cm−2 in the benthos. The in vivo absorbance characteristics of isolates from these environments indicated a genetically diverse
range of species in each group of Arctic cyanobacteria. Growth versus irradiance relationships were determined for each of
the isolates and similarly revealed large genetic differences (maximum growth rates from 0.17 to 0.61 day−1), even between morphologically identical taxa. A comparison of nutrients, pigment concentrations and species composition
underscores the strong similarities between freshwater ecosystems in the north and south polar zones.
Received: 3 June 1996 / Accepted: 3 November 1996 相似文献
4.
In order to develop a novel transdermal drug delivery system that facilitates the skin permeation of finasteride encapsulated
in novel lipid-based vesicular carriers (ethosomes)finasteride ethosomes were constructed and the morphological characteristics
were studied by transmission electron microscopy. The particle size, zeta potential and the entrapment capacity of ethosome
were also determined. In contrast to liposomes ethosomes were of more condensed vesicular structure and they were found to
be oppositely charged. Ethosomes were found to be more efficient delivery carriers with high encapsulation capacities. In vitro percutaneous permeation experiments demonstrated that the permeation of finasteride through human cadaver skin was significantly
increased when ethosomes were used. The finasteride transdermal fluxes from ethosomes containing formulation (1.34 ± 0.11 μg/cm2/h) were 7.4, 3.2 and 2.6 times higher than that of finasteride from aqueous solution, conventional liposomes and hydroethanolic
solution respectively (P < 0.01).Furthermore, ethosomes produced a significant (P < 0.01) finasteride accumulation in the skin, especially in deeper layers, for instance in dermis it reached to 18.2 ± 1.8 μg/cm2. In contrast, the accumulation of finasteride in the dermis was only 2.8 ± 1.3 μg/cm2 with liposome formulation. The study demonstrated that ethosomes are promising vesicular carriers for enhancing percutaneous
absorption of finasteride. 相似文献
5.
In this work, an over-expressed cyclobutane pyrimidine dimer (CPD) photolyase of Synechococcus sp. PCC 7942 was used to investigate UV-C (ultraviolet irradiation of C-region) influence on photoreactivation. In vivo photoreactivation experiments indicated that the survival rate decreased from 100 to 2.6% when the UV-C flux was increased
from 1.1 to 68.5 μW/cm2. It seemed that the photolyase was easily inactivated at UV-C intensities ≥25.5 μW/cm2. Spectrometric analysis indicated that tertiary structure of the photolyase changed evidently when the UV-C fluxes were ≥25.5
μW/cm2, while the secondary structure was almost unchanged even at 170 μW/cm2. Band shift assay indicated that catalytic activity of the photolyase was impaired at fluxes ≥25.5 μW/cm2, but no significant influence on DNA-binding activity was observed. These results suggest that photoreactivation is efficient
at UV-C fluxes ≤25.5 μW/cm2, but would be impaired by intense UV-C irradiation due to structure changes of the photolyase.
Published in Russian in Biokhimiya, 2007, Vol. 72, No. 5, pp. 668–673. 相似文献
6.
Regalado EL Rodríguez M Menéndez R Concepción AA Nogueiras C Laguna A Rodríguez AA Williams DE Lorenzo-Luaces P Valdés O Hernandez Y 《Marine biotechnology (New York, N.Y.)》2009,11(1):74-80
Daily topical application of the aqueous ethanolic extract of the marine sea grass, Thalassia testudinum, on mice skin exposed to UVB radiation resulted in a dose-dependent recovery of the skin macroscopic alterations over a 6-day
period. Maximal effect (90%) occurred at a dose of 240 μg/cm2, with no additional effects at higher doses. Bioassay-guided fractionation of the plant extract resulted in the isolation
of thalassiolin B (1). Topical application of 1 (240 μg/cm2) markedly reduces skin UVB-induced damage. In addition, thalassiolin B scavenged 2,2-diphenyl-2-picrylhydrazyl radical with
an EC50 = 100 μg/ml. These results suggest that thalassiolin B is responsible for the skin-regenerating effects of the crude extract
of T. testudinum.
Erik L. Regalado and María Rodríguez have contributed equally to this work and should be considered as first authors. 相似文献
7.
Jordi Urmeneta Óscar Alcoba Efrén Razquín Elena Tarroja Antoni Navarrete Ricardo Guerrero 《Current microbiology》1998,37(3):151-155
Photosynthetic and respiratory activities at low light intensities (300 μE m−2 s−1) in the microbial mats of the Ebro Delta were measured by the oxygen exchange method in the laboratory. The response to H2S concentration, a significant factor in the dynamics of that ecosystem, was assessed. Total photosynthesis reached 23.78–28.17
μg O2 cm−2 h−1. Photosynthetic activity was not significantly different at the two temperatures tested. Respiratory activity reached a consumption
of 6.95–8.56 μg O2 cm−2 h−1 at 25°C and 11.42–11.70 μg O2 cm−2 h−1 at 35°C. The Q10 value for respiration was 1.37–1.64. Oxygen production in Microcoleus chthonoplastes, the most abundant cyanobacterium in those microbial mats, was highly resistant to sulfide inhibition. Concentrations less
than 0.02 mM sulfide did not affect the rate of photosynthesis. Concentrations up to 0.1 mM sulfide caused different degrees
of partially reversible inhibition, with a maximum of 67% at 0.78 mM sulfide. Primary production (g C assimilated/m2/year) in those microbial mats was also assessed and compared with data from other ecosystems.
Received: 24 October 1997 / Accepted: 18 December 1997 相似文献
8.
Jennifer R. McKelvie Jimmy Yuk Yunping Xu Andre J. Simpson Myrna J. Simpson 《Metabolomics : Official journal of the Metabolomic Society》2009,5(1):84-94
The metabolic response of the earthworm Eisenia fetida to two pesticides, dichlorodiphenyltrichloroethane (DDT) and endosulfan, was characterized in contact tests using proton
nuclear magnetic resonance (1H NMR) and principal component analysis (PCA). PCA loading plots suggested that maltose, leucine and alanine were important
metabolites contributing to the differences in dosed and control earthworms for both compounds at doses of 0.5, 1.0 and 2.0 μg/cm2. Gas chromatography/mass spectrometry (GC/MS) was used to quantify the metabolites identified in E. fetida and determine if the changes in maltose, leucine and alanine following exposure to DDT and endosulfan (at 0.5 and 1.0 μg/cm2) were reproducible and greater than the natural variability. Quantification by GC/MS suggested that maltose was not a reliable
biomarker since it both increased and decreased in earthworms exposed to DDT and increased by just 3% with exposure to endosulfan.
Leucine was not stable with the GC/MS derivitization method used in this study and could not be confirmed as a reliable biomarker.
However, alanine consistently increased for both DDT and endosulfan exposed E. fetida. Alanine showed considerable variability in control earthworms (±41.6%), yet the variability in alanine to glycine ratios
was just ±10.5%. Increases in the alanine to glycine ratio were statistically significant at the P = 0.05 level for the 1.0 μg/cm2 DDT dose and both the 0.5 and 1.0 μg/cm2 endosulfan doses, suggesting that deviations from the normal homeostatic ratio of 1.5 for alanine to glycine is a potential
biomarker of DDT and endosulfan exposure warranting further study.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Environmental Metabolomics Special Issue of Metabolomics. 相似文献
9.
One hundred nine isolates of 10 genera representing 20 species of keratinophilic fungi were isolated from soil of planted
earthen pots in indoor environments of 15 localities of Kanpur, India, by the hair baiting technique. Microsporum gypseum, Trichophyton vanbreuseghemii, and Botryotrichum piluliferum were found to release 698.66, 512.99, and 519.99 μg/ml net protein, respectively, whereas Arthroderma cuniculi released the minimum, 107.99 μg/ml. All other isolates were keratinolytically active. 相似文献
10.
In the present study attempt was made for preparation of isotretinoin-hydroxypropyl β cyclodextrin (HP-β-CD) inclusion complex
and encapsulate this complex in elastic liposomes to study the effect of dual carrier approach on skin targeting of isotretinoin.
The isotretinoin HP-β-CD complex was prepared by freeze-drying method and characterized by IR spectroscopy. The drug and drug-CD
complex loaded elastic liposomal formulation were prepared and characterized in vitro, ex-vivo and in vivo for shape, size, entrapment efficiency, no. of vesicles per cubic mm, in vitro skin permeation and deposition study, photodegradation and skin toxicity assay. The transdermal flux for different vesicular
formulations was observed between 10.5 ± 0.5 to 13.9 ± 1.6 μg/cm2/h. This is about 15-21 folds higher than that obtained from drug solution (0.7 ± 0.1 μg/cm2/h) and 4-5 folds higher than obtained with drug-CD complex solution (2.7 ± 0.1 μg/cm2/h). The amount of drug deposit was found to increase significantly (p < 0.05) by cyclodextrin complexation (30.1 ± 0.1 μg). The encapsulation of this complex in elastic liposomal formulation
further increases its skin deposition (262.2 ± 21 μg). The results of skin irritation study using Draize test also showed
the significant reduction in skin irritation potential of isotretinoin elastic liposomal formulation in comparison to free
drug. The results of the present study demonstrated that isotretinoin elastic liposomal formulation possesses great potential
for skin targeting, prolonging drug release, reduction of photodegradation, reducing skin irritation and improving topical
delivery of isotretinoin. 相似文献
11.
The epilithic biomass of an outflow stream at Potter Peninsula (King George Island, Antarctica) was studied from November
1996 to February 1997 by means of chlorophyll a concentration, dry weight and ash-free dry weight. The Autotrophic Index and the Lakatos classification were also used in
order to characterize the epilithic community. Several physical and chemical parameters were analyzed. Snow and ice melt greatly
increased water flow through Tres Hermanos Lake and in the stream. Chlorophyll a concentrations fluctuated between undetectable and 3.5 μg cm−2 with a marked increase, which averaged 3 orders of magnitude, towards the end of the study period. Dry weight ranged between
299.9 and 13,118.7 μg cm−2 and ash-free dry weight between 70.8 and 996.9 μg cm−2. According to the Autotrophic Index and the Lakatos classification, the epilithon of the stream had a low mass with low organic
component and large amount of inorganic sediment. The organic matter comprised a low proportion of chlorophyll a and a major proportion of probably detritus or bacteria, rather than fauna.
Accepted: 3 June 2000 相似文献
12.
Control of Transdermal Permeation of Hydrocortisone Acetate from Hydrophilic and Lipophilic Formulations 总被引:1,自引:0,他引:1
The purpose of this research was the preparation of four formulations containing hydrocortisone acetate (HCA) for topical
application, including two aqueous systems (hydrophilic microemulsion and aqueous gel) and two systems with dominant hydrophobicity
(hydrophobic microemulsion and ointment). The formulations were tested for the release and permeation of HCA across an animal
membrane. The release of HCA was found comparable for the four systems. The two microemulsions promote permeation across an
ex-vivo membrane, examined by means of a Franz cell. Hydrophobic microemulsion guarantees the highest solubility (2,370 μg/ml) and
flux (133 μg/cm2.h) of the drug, since it contains almost 40% Transcutol, a permeation enhancer. Gel and ointment provide lower solubility
and flux, being the values, related to the ointment, the lowest ones (562 μg/ml and 0.4 μg/cm2.h). Experimental results allow the conclusion that gel and ointment can be suitable when it is desirable to minimize absorption
of topically applied HCA as to keep the drug restricted to the diseased area and prevent side effects of the systemic presence
of HCA. 相似文献
13.
The present research work was aimed to formulate clotrimazole encapsulated Cavamax W7 composite ethosomes by injection method
for improved delivery across epidermis. 32 factorial design was used to design nine formulations (F1-F9) and compared with ethosomal formulations (F10-F12). F9 with
vesicle size of 202.8 ± 4.8 nm, highest zeta potential (−83.6 ± 0.96 mV) and %EE of 98.42 ± 0.15 was selected as optimized
composite ethosome and F12 as reference ethosomal formulation. As revealed by transmission electron microscopy F9 vesicles
were more condensed, uniformly spherical in shape than F12 vesicles. Vesicular stability studies indicated F9 to be more stable
as compared to F12. Both F9 and F12 were incorporated in carbopol 934 gel base to get G1–G8 gel formulations and evaluated
for in vitro skin permeability. Cavamax W7 composite ethosomal optimized gel (G5) showed higher in vitro percent cumulative drug permeation (88.53 ± 2.10%) in 8 h and steady state flux (J
ss) of 3.39 ± 1.45 μg/cm2/min against the J
ss of 1.57 ± 0.23 μg/cm2/min for ethosomal gel (G1) and 1.13 ± 0.06 μg/cm2/min for marketed formulation. The J
ss flux of G5 was independent of amount of drug applied/unit area of skin. In vivo confocal laser scanning microscopic study of G5 depicted uniform and deeper penetration of rhodamine B (marker) in epidermis
from Cavamax W7 composite ethosomal gel in comparison to G1. Finally, G5 demonstrated better (p < 0.05) antifungal activity against Candida albicans and Aspergillus niger than G1 thus, signifying that Cavamax W7 composite ethosomes present a superior stable and efficacious vesicular system than
ethosomal formulation for topical delivery of clotrimazole. 相似文献
14.
We hypothesized that inhibition and activation of basolateral to luminal chloride transport mechanisms were associated with
respective decreases and increases in basolateral to luminal water fluxes. The luminal to basolateral (J
W
L→B
) and basolateral to luminal (J
W
B→L
) water fluxes across ovine tracheal epithelia were measured simultaneously. The mean J
W
L→B
(6.5 μl/min/cm2) was larger than J
W
B→L
(6.1 μl/min/cm2). Furosemide reduced J
W
B→L
from 6.0 to 5.6 μl/min/cm2. Diphenylamine-2-carboxylate (DPC) reduced J
W
B→L
from 7.9 to 7.3 μl/min/cm2 and reduced the membrane potential difference by 38%. Furosemide together with DPC decreased J
W
L→B
by 30% and J
W
B→L
by 15%. Norepinephrine increased J
W
B→L
from 4.9 to 6.0 μl/min/cm2. Neuropeptide Y in the presence of norepinephrine decreased J
W
L→B
(6.4 to 5.2 μl/min/cm2) and returned J
W
B→L
to its baseline value. Vasopressin increased J
W
B→L
from 4.1 to 5.1 μl/min/cm2. Endothelin-1 induced a simultaneous increase in J
W
B→L
(7.0 to 7.7 μl/min/cm2) and decrease in J
W
L→B
(7.4 to 6.4 μl/min/cm2); and decreased the membrane resistance. These data indicate that in tracheal epithelia under homeostatic conditions J
W
B→L
has a ∼15% actively coupled component. Consistent with our hypothesis, inhibition and receptor-induced stimulation of chloride
effluxes were associated with decreases and increases in J
W
B→L
, respectively. However, as inhibition of transcellular chloride transport always decreased J
W
L→B
more than J
W
B→L
, reducing transepithelial chloride transport did not result in less water being transported into the airway lumen.
Received: 12 October 1999/Revised: 14 March 2000 相似文献
15.
The purpose of this study was to investigate the effects of vehicles, enhancers, and polymer membranes on 3-azido-3-deoxythymidine
(AZT) permeation across cadaver pig skin. Four binary vehicles (ethanol/water, isopropyl alcohol/water, polyethylene glycol
400/water, and ethanol/isopropyl myristate [IPM] were tested for AZT solubility and permeability across pig skin; ethanol/IPM
(50/50, vol/vol) demonstrated the highest AZT flux (185.23 μ/cm2/h). Next, the addition of various concentrations of different enhancers (N-methyl-2-pyrrolidone [NMP], oleic acid, and lauric acid) to different volume ratios of ethanol/IPM was investigated for their
effect on AZT solubility and permeability across pig skin. The use of 2 conbinations (ethanol/IPM [20/80] plus 10% NMP and
ethanol/IPM [30/70] plus 10% NMP) resulted in increased AZT solubility (42.6 and 56.27 mg/mL, respectively) and also high
AZT flux values (284.92 and 460.34 μg/cm2/h, respectively) without appreciable changes in lag times (6.25 and 7.49 hours, respectively) when compared with formulations
using only ethanol/IPM at 20/80 and 30/70 volume ratios without addition of the enhancer NMP. Finally, AZT permeation across
pig skin covered with a microporous polyethylene (PE) membrane was investigated. The addition of the PE membrane to the pig
skin reduced AZT flux values to ∼50% of that seen with pig skin alone. However, the AZT flux value attained with ethanol/IPM
(30/70) plus 10% NMP was 215.30 μg/cm2/h, which was greater than the target flux (208 μg/cm2/h) needed to maintain the steady-state plasma concentration in humans. The results obtained from this study will be helpful
in the development of an AZT transdermal drug delivery system. 相似文献
16.
In 12 selected flats in Sosnowiec, Upper Silesia, the concentrations of particulate aerosol, bioaerosol and bacterial endotoxin
were examined. Concentrations of particulate aerosol, bacteria, fungi and endotoxin were in the order of 101–102
μg/m3, 101–103 cfu/m3, 100–102 cfu/m3 and 10−2–10−1 ng/m3, respectively. The most numerous group of microorganisms in indoor air during the winter season were Gram positive mesophilic
bacteria. They were more common in flats polluted with tobacco smoke. The concentrations of airborne endotoxins were higher
in flats polluted with tobacco smoke in all size ranges. The highest level of endotoxins was found in the fraction of fine
particles below 5μm. 相似文献
17.
Quantification of arbuscular mycorrhizal fungi activity by the glomalin concentration on hyphal traps 总被引:9,自引:0,他引:9
Strips of horticultural film (16–32 cm2) were used to trap extraradical hyphae emanating from roots of sudangrass [Sorghum sudanense (Piper) Staph] enclosed in 40-μm mesh bags and colonized by Gigaspora rosea FL 224-1, Glomus intraradices EY 113/114, or Glomus caledonium UK 301-1. Strips of film were placed at opposite sides of 17–21 replicate sand culture pots for each isolate and were removed
after 12–14 weeks of plant growth. To extract glomalin, a strip was cut into small pieces and submerged in 2 ml of 20 mM citrate,
pH 7.0 and then autoclaved for 60 min. A quantitative enzyme-linked immunosorbent assay (ELISA) detected 0.005–0.04 μg glomalin
in the volume of extract tested. The Bradford protein assay detected 1.25–5 μg of protein in the volume of extract tested.
Both assays gave results ranging from 5–40 μg glomalin/cm2 of film. Protein assay values were correlated with ELISA values (r=0.6091, P≤0.001, n=118). Analysis of variance indicated that isolates differed in Bradford protein values (P=0.001), but not ELISA values (P=0.154). Spatial variability of glomalin deposition ca. 7 cm from roots on opposite sides of pots was indicated by significant
paired T tests (P<0.05) for protein values for each of the three isolates and ELISA for two isolates. These results indicate that hyphal traps,
Bradford protein assay and ELISA are useful to assess hyphal activity over a growing season.
Accepted: 11 October 1998 相似文献
18.
A combination of lipid synthesis inhibitors was used to enhance the in vitro and in vivo permeation of levodopa (LD) across
rat epidermis, and their influence on epidermal lipids was investigated using attenuated total reflectance Fourier transform
infrared (ATR-FTIR) spectroscopy. Rat epidermis was treated with ethanol and a combination of atorvastatin (750 μg/7 cm2), cerulenin (20 μg/7 cm2), and β-chloroalanine (600 μg/7 cm2) for sustaining the reduced content of epidermal cholesterol, fatty acids (as triglycerides), and ceramide (as sphingosine),
respectively, in viable rat skin. This treatment resulted in significant (P<.05) synthesis inhibition of skin lipids up to 48 hours and 6-fold enhancement in the in vitro permeation of LD. The effective
plasma concentration of LD was achieved within 1 hour and maintained over 48 hours after topical application to rat epidermis
treated with a combination of these lipid synthesis inhibitors. ATR-FTIR studies of inhibitor(s)-treated rat epidermis revealed
a significant decrease (P<.05) in peak height and area for both asymmetric and symmetric C−H stretching absorbances, suggesting extraction of lipids.
However, an insignificant (P<.05) shift in the frequency of these peaks suggested no fluidization of epidermal lipids by lipid synthesis inhibitors. A
direct correlation was observed between epidermal lipid synthesis inhibition, decrease in peak height or area, and percutaneous
permeation of LD. Skin lipid synthesis inhibition by a combination of lipid synthesis inhibitors seems to offer a feasible
approach for enhancing the transcutaneous delivery of LD.
Published: October 24, 2005 相似文献
19.
Mullins C Hartnell LM Wassarman DA Bonifacino JS 《Molecular & general genetics : MGG》1999,262(3):401-412
The adaptor protein (AP) complexes AP-1, AP-2, and AP-3 mediate coated vesicle formation and sorting of integral membrane
proteins in the endocytic and late exocytic pathways in mammalian cells. A search of the Drosophila melanogaster expressed sequence tag (EST) database identified orthologs of family members mammalian medium (μ) chain families μ1, μ2,
and μ3, of the corresponding AP complexes, and δ-COP, the analogous component of the coatomer (COPI) complex. The Drosophila
orthologs exhibit a high degree of sequence identity to mammalian medium chain and δ-COP proteins. Northern analysis demonstrated
that medium chain and δ-COP mRNAs are expressed uniformly throughout fly development. Medium chain and δ-COP genes were cytologically
mapped and the μ3 gene was found to localize to a region containing the pigmentation locus carmine (cm). Analysis of genomic DNA of the cm
1
mutant allele indicated the presence of a large insertion in the coding region of the μ3 gene and Northern analysis revealed
no detectable μ3 mRNA. Light microscopy of the cm
1
mutant showed a reduction in primary, secondary, and tertiary pigment granules in the adult eye. These findings provide evidence
of a role for μ3 in the sorting processes required for pigment granule biogenesis in Drosophila.
Received: 7 June 1999 / Accepted: 4 July 1999 相似文献
20.
Abrevaya XC Sacco N Mauas PJ Cortón E 《Extremophiles : life under extreme conditions》2011,15(6):633-642
In this work, two archaea microorganisms (Haloferax volcanii and Natrialba magadii) used as biocatalyst at a microbial fuel cell (MFC) anode were evaluated. Both archaea are able to grow at high salt concentrations.
By increasing the media conductivity, the internal resistance was diminished, improving the MFC’s performance. Without any
added redox mediator, maximum power (P
max) and current at P
max were 11.87/4.57/0.12 μW cm−2 and 49.67/22.03/0.59 μA cm−2 for H. volcanii, N. magadii and E. coli, respectively. When neutral red was used as the redox mediator, P
max was 50.98 and 5.39 μW cm−2 for H. volcanii and N. magadii, respectively. In this paper, an archaea MFC is described and compared with other MFC systems; the high salt concentration
assayed here, comparable with that used in Pt-catalyzed alkaline hydrogen fuel cells, will open new options when MFC scaling
up is the objective necessary for practical applications. 相似文献