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101.
We present a protocol for building and operating a microfluidic device for mechanical immobilization of Caenorhabditis elegans in its physiologically active state. The system can be used for in vivo imaging of dynamic cellular processes such as cell division and migration, degeneration, aging and regeneration, as well as for laser microsurgery, Ca2+ imaging and three-dimensional microscopy. The device linearly orients C. elegans, and then completely restrains its motion by pressing a flexible membrane against the animal. This technique does not involve any potentially harmful anesthetics, gases or cooling procedures. The system can be installed on any microscope and operated using only one syringe and one external valve, making it accessible to most laboratories. The device fabrication begins by patterning photoresist structures on silicon wafers, which are then used to mold features in elastomeric layers that are thermally bonded to form the device. The system can be assembled within 3 d. 相似文献
102.
103.
We use genomics to identify the natal origin of a grey whale found in the South Atlantic, at least 20 000 km from the species core range (halfway around the world). The data indicate an origin in the North Pacific, possibly from the endangered western North Pacific population, thought to include only approximately 200 individuals. This contributes to our understanding of Atlantic sightings of this species known primarily from the North Pacific, and could have conservation implications if grey whales have the potential for essentially global dispersion. More broadly, documenting and understanding rare extreme migration events have potential implications for the understanding of how a species may be able to respond to global change. 相似文献
104.
Fatih Kaburcuk 《Electromagnetic biology and medicine》2019,38(2):168-176
In this paper, effects of a brain tumor located in a dispersive human head model on specific absorption rate (SAR) and temperature rise distributions due to different types of RF sources at 4G and 5G cellular frequencies are investigated with the use of a multiphysics model. This multiphysics model analyzes the dispersive human head with the brain tumor and provides the SAR and temperature rise distributions in the head due to the RF source operated at 4G and 5G cellular frequencies in a single finite-difference time-domain simulation. An adjacent antenna operated at 4G and 5G cellular frequencies to the human head is considered as the RF source for near-field exposure, while a plane wave field radiated by base stations operated at 4G and 5G cellular frequencies is considered as the RF source for far-field exposure. Numerical results show that the brain tumor in the head slightly affects the SAR and temperature rise distributions due to different RF sources at 4G and 5G cellular frequencies. 相似文献
105.
Differential expression of proliferative, cytoskeletal, and adhesive proteins during postnatal development of the hamster submandibular gland 总被引:1,自引:1,他引:0
Fernandes RP Cotanche DA Lennon-Hopkins K Erkan F Menko AS Kukuruzinska MA 《Histochemistry and cell biology》1999,111(2):153-162
Although the submandibular gland (SMG) plays important exocrine and endocrine roles, little is known about the molecular
details underlying its development. Previously, we reported that in the postnatally developing hamster SMG, GPT, the protein
product of the first N-glycosylation gene, ALG7, was an in vivo marker for salivary cell proliferation. Here we investigated the proliferative,
cytoskeletal, and adhesive changes during SMG postnatal development. The cellular localization and abundance of GPT, filamentous
actin, and β1 integrin receptor were examined using confocal microscopy and immunoblotting. In neonatal glands, high GPT levels
marked extensive cell proliferation throughout the tissue. The apical regions of immature salivary cells displayed intense
actin staining, while most of the β1 integrin was diffusely distributed throughout the tissue. As development proceeded, discrete
regions of the gland expressed attenuated levels of GPT, an increased organization of actin to the cell cortex, and β1 integrin
to the basal lamina. In the adult SMG, differentiated salivary cells displayed low levels of GPT and actin. While the abundance
of β1 integrin remained unchanged throughout development, in the adult, it was found exclusively in regions where cells contact
the basal lamina. These data indicate that SMG development entails regionalized cell proliferation and polarization, and that
these processes are temporally and spatially coordinated with the establishment of stable cell-substratum interactions.
Accepted: 26 October 1998 相似文献
106.
The purpose of the study was to synthesize and evaluate the antimicrobial effects of two monophosphazenes, N-diphenylphosphoryl-P-triphenylmonophosphazene-II and N-di(o-tolyl)phosphoryl-P-tri(o-tolyl)monophosphazene-III on bacterial and yeast strains. The biological effects of these molecules were compared with a potential antioxidant vitamin E. According to results, the triphenyl monophosphazene-II has antimicrobial effect on all the bacterial and yeast cells, but tri(o-tolyl)monophosphazene-III has only antimicrobial effect on some bacterial cells. When the concentration of triphenyl monophosphazene-II was raised, it was observed that inhibition zone increased on the bacterial growth media. The biological effects of these molecules were compared to vitamin E in the Saccharomyces cerevisiae culture media. In 200 microg administered culture media, the cell density decreased in vitamin E, triphenyl monophosphazene-II and tri(o-tolyl)monophosphazene-III groups at the end of 24 and 48 h incubation times (p<0.001,p<0.05). While the cell densities in vitamin E and tri(o-tolyl)monophosphazene-II groups decreased partly at the end of 72 h incubation time (p<0.05), its level in triphenyl monophosphazene-II group increased (p<0.01) at the same incubation time. In 1,000 microg administered culture media, cell density was not found to differ between vitamin E and control groups at the end of 24h incubation time, but it was found that the cell densities in triphenyl monophosphazene and tri(o-tolyl)monophosphazene-III groups decreased at the same incubation time (p<0.001). The cell densities in tri(o-tolyl)monophosphazene-III group and triphenyl monophosphazene-II decreased at the end of 48 h incubation time (respectively, p<0.05,p<0.001). In 200 microg administered cell pellets, while the lipid level was not found to differ between control and vitamin E, the lipid level decreased in triphenyl monophosphazene-II and tri(o-tolyl)monophospazene-III groups (respectively, p<0.001,p<0.01). In 1,000 microg administered cell pellets, it was found that the lipid level decreased in vitamin E, triphenyl monophosphazene-II and tri(o-tolyl)monophosphazene-III groups (p<0.001,p<0.01). 相似文献
107.
Quanzhi Li Wendy Hudson Duo Wang Erica Berven Fatih M. Uckun John H. Kersey 《Cancer immunology, immunotherapy : CII》1998,47(3):121-130
The comparative advantages and disadvantages of intact antibodies and single-chain Fv as immunotoxins and radioimmunoconjugates
have been widely discussed but not directly compared. In this study, the in vivo properties of anti-CD19 B43 monoclonal antibody
and its derived single-chain Fv (FVS191) were studied in athymic nude mice bearing CD19-positive human lymphomas. B43 mab
and FVS191 were labeled with iodine-125 using iodine-beads, and immunoreactivities were determined to be 57% and 72%, respectively.
Scatchard analysis showed a similar high affinity for both. The results of pharmacokinetic studies revealed that FVS191 had
a rapid biphasic clearance from the circulation (T1/2α = 2.5 min, T1/2β = 3.7 h); The T1/2α and T1/2β phases of B43 mab were
determined to be 0.72 h and 57 h respectively. Biodistribution studies compared the uptake of labeled antibodies by CD19-positive
and by CD19-negative tumors. The peak percentages of injected dose were 5.7% at 12 h for B43 and 2.45% at 1 h for FVS191.
Radiolocalization indices (RI) demonstrated tumor-specific uptake for both, but higher uptake for B43. The optimal RI was
seen at 15 min for FVS191 and 6 h for B43. FVS191 was unstable in vivo, approximately 50% of the injected dose being degraded
in blood in 100 min. Radioactivity detected in the urine was present mainly as the deiodinized form of FVS191. The results
suggest that B43 mab is favored over FVS191 in biodistribution properties and in vivo stability. Because B43 Mab showed early
tumor-specific uptake, high RI values, and favorable tissue-to-blood ratios, it is a potential candidate for radioimmunotherapy
and immunotoxin therapy of B-cell leukemia and lymphoma.
Received: 17 June 1997 / Accepted: 17 June 1998 相似文献
108.
Fatih Karadagli Andrew Marcus Bruce E. Rittmann 《Biotechnology and bioengineering》2023,120(7):1844-1856
Hydrogen (H2) concentrations that were associated with microbiological respiratory processes (RPs) such as sulfate reduction and methanogenesis were quantified in continuous-flow systems (CFSs) (e.g., bioreactors, sediments). Gibbs free energy yield (ΔǴ ~ 0) of the relevant RP has been proposed to control the observed H2 concentrations, but most of the reported values do not align with the proposed energetic trends. Alternatively, we postulate that system characteristics of each experimental design influence all system components including H2 concentrations. To analyze this proposal, a Monod-based mathematical model was developed and used to design a gas–liquid bioreactor for hydrogenotrophic methanogenesis with Methanobacterium bryantii M.o.H. Gas-to-liquid H2 mass transfer, microbiological H2 consumption, biomass growth, methane formation, and Gibbs free energy yields were evaluated systematically. Combining model predictions and experimental results revealed that an initially large biomass concentration created transients during which biomass consumed [H2]L rapidly to the thermodynamic H2-threshold (≤1 nM) that triggerred the microorganisms to stop H2 oxidation. With no H2 oxidation, continuous gas-to-liquid H2 transfer increased [H2]L to a level that signaled the methanogens to resume H2 oxidation. Thus, an oscillatory H2-concentration profile developed between the thermodynamic H2-threshold (≤1 nM) and a low [H2]L (~10 nM) that relied on the rate of gas-to-liquid H2-transfer. The transient [H2]L values were too low to support biomass synthesis that could balance biomass losses through endogenous oxidation and advection; thus, biomass declined continuously and disappeared. A stable [H2]L (1807 nM) emerged as a result of abiotic H2-balance between gas-to-liquid H2 transfer and H2 removal via advection of liquid-phase. 相似文献
109.
110.
Demirci F Noma Y Kirimer N Can Başer KH 《Zeitschrift für Naturforschung. C, Journal of biosciences》2004,59(5-6):389-392
The cyclic monoterpene ketone (-)-carvone was metabolized by the plant pathogenic fungus Absidia glauca. After 4 days of incubation, the diol 10-hydroxy-(+)-neodihydrocarveol was formed. The absolute configuration and structure of the crystalline substance was identified by means of X-ray diffraction and by spectroscopic techniques (MS, IR and NMR). The antimicrobial activity of the substrate and metabolite was assayed with human pathogenic microorganisms. 相似文献