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51.
Internal pH (pHi) was determined inEmiliania huxleyi (Lohmann) using the probe 2,7-bis-(2-carboxyethyl)-5(and-6)carboxyfluoresceinacetoxymethylester (BCEF-AM) and digital imaging microscopy. The probe BCECF-AM was taken up and hydrolysed to the free acid by the cells. A linear relationship was established between pHi and the 490/450 fluorescence ratio of BCECF-AM over the pH range 6.0 to 8.0 using the ionophore nigericin. Two distinct pH domains were identified within the cell, the cytoplasmic domain (approx. pH 7.0) and the chloroplast domain (approx. pH 8.0). The average pHi was 7.29 (±0.11) for cells in the presence of 2 mM HCO
3
–
. In the absence of HCO
3
–
the pHi was decreased by 0.8 pH unit. The importance of these changes in pHi is considered in relation to inorganic-carbon uptake.Abbreviations AM
acetoxymethylester
- BCECF
2,7-bis-(2-carboxyethyl)-5(and-6)carboxyfluorescein
- Hepes
4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid
- pHi
intracellular pH 相似文献
52.
Heinz Brehme 《American journal of physical anthropology》1975,42(2):255-262
The characteristics of the epidermal ridge system were studied in a series of eighteen lesser or pygmy chimpanzees (Pan paniscus). The general ridge alignments are very similar to those of the chimpanzee (Pan troglodytes); Biegert ('61). On the average the pattern intensity (P.I.) of the palm configurations is considerably higher in the pygmy chimpanzee than in the chimpanzee, thus representing the highest total palm pattern intensity of all species of the Hominoidea. The sole configurations show parallel main results to those of the palm; however, the decreased sole pattern frequency of the pygmy chimpanzee is of a smaller predominance only as compared to the values of the other species of this superfamily. The preliminary data on the finger tip patterns, translated into P.I. values, are much higher than in chimpanzees and within the range of the mean values of gorillas (Brehme, '73), while those of the toes of pygmy chimpanzees seem to possess the lowest P.I. values of the African apes. 相似文献
53.
Intraepidermal nerves in human digital skin 总被引:3,自引:0,他引:3
Summary Intraepidermal nerve fibers of human glabrous digital skin were investigated using a new silver impregnation method. Nerves were observed to enter the epidermis without regional preference, and to extend into the stratum granulosum. They are non-varicose (smooth) or varicose and range from less than 0.2 m to approximately 2 m in diameter, with varicosities up to 3 m in diameter. Some axons branch profusely within the epithelium, giving off fine branches of differing diameters, while others appear to remain unbranched. At least some intraepidermal axons are fine branches of larger axons taking a horizontal course below the epithelial layer. Others are, at least topically, closely associated with Meissner's corpuscles. At 57 nerves per mm2 surface area, the density of intraepidermal nerves found in this investigation is much greater than that reported in recent publications, and agrees closely with values given in several older studies.Dedicated to Prof. Dr. A. Hopf on the occasion of his 65th birthday 相似文献
54.
Tadashi Yasui Azuma Tsukise Anke Schnapper Wilfried Meyer 《European Journal of Wildlife Research》2008,54(2):275-283
Numerous and very large Vater-Pacini corpuscles were observed in the forefoot digital pads of the North American raccoon (Procyon lotor). In addition to ultrastructure, the distribution and selectivity of complex glycoconjugates in this sensory corpuscle type
were examined by carbohydrate histochemical techniques, in particular lectin histochemistry. The Vater-Pacini corpuscles present
showed the typical lamellar structure known for mammals and contained high amounts of neutral and acidic glycoconjugates with
various saccharide residues (α-l-fucose, β-d-galactose, sialic acid) in a specific intracorpuscular distribution pattern, including variations between the outer lamellae
and the inner core. The results obtained are discussed with regard to possible functions of the Vater-Pacini corpuscles found
in the raccoon forefoot pads. The corpuscular glycoconjugate components may furnish a high and differentiated viscoelasticity
for rapid pressure transmission within the large Vater-Pacini corpuscles. Thus, the digital pads of the forepaws can be considered
as part of a specific mechanoreceptor system related to excellent object manipulation properties in this mammalian species. 相似文献
55.
Abstract A combined subtraction hybridization and polymerase chain reaction/amplification technique was used to develop a DNA probe which was specific for the Rhizobium leguminosarum biovar phaseoli and the Rhizobium tropici group. Total genomic DNA preparations from Rhizobium leguminosarum biovar viciae, Rhizobium leguminosarum biovar trifolii, Rhizobium sp., Agrobacterium tumefaciens, Rhizobium fredii, Bradyrhizobium japonicum, Bradyrhizobium ssp. and Rhizobium meliloti were pooled and used as subtracter DNA against total genomic DNA from the Rhizobium leguminosarum biovar phaseolo strain KIM5s. Only one round of subtraction hybridization at 65°C was necessary to remove all cross-hybridizing sequences. Dot blot hybridizations with total genomic DNA of the eight subtracter organisms and 29 bacteria of different groups confirmed the high specificity of the isolated DNA sequences. Dot blot hybridizations and total genomic DNA from ten different R. Leguminosarum biovar phaseoli and R. tropici strains resulted in strong hybridization signals for all strains tested. The DNA probe for the R. tropici and R. leguminosarum biovar phaseoli group was used for dot blot hybridization with DNA extracts from three tropical and one boreal soil. When correlated with data from Most Probable Number analyses the probe was capable of detecting as low as 3 × 104 homologous indigenous rhizobia per g soil. The technique offers great benefits for the development of DNA probes for monitoring bacterial populations in environmental samples. 相似文献
56.
M. I. Arrieta M. A. Ibarrondo A. Simon C. M. Lostao 《International Journal of Anthropology》1987,2(2):117-123
Fingers pattern types of a sample of 834 unrelated individuals (353 males and 481 females) from the Biscaian Basque valleys
of Uribe, Gernika, Markina, Arratia and Durango were subjected to correspondence analysis. The results show that there are
different local subpopulations with regard to these dermatoglyphic traits. The importance of whorls in the separation of these
populations is observed. Isolation may have been the factor differentiating between the valleys. 相似文献
57.
Real-time PCR has been widely used to evaluate gene abundance in natural microbial habitats. However, PCR-inhibitory substances often reduce the efficiency of PCR, leading to the underestimation of target gene copy numbers. Digital PCR using microfluidics is a new approach that allows absolute quantification of DNA molecules. In this study, digital PCR was applied to environmental samples, and the effect of PCR inhibitors on DNA quantification was tested. In the control experiment using λ DNA and humic acids, underestimation of λ DNA at 1/4400 of the theoretical value was observed with 6.58ngμL(-1) humic acids. In contrast, digital PCR provided accurate quantification data with a concentration of humic acids up to 9.34ngμL(-1). The inhibitory effect of paddy field soil extract on quantification of the archaeal 16S rRNA gene was also tested. By diluting the DNA extract, quantified copy numbers from real-time PCR and digital PCR became similar, indicating that dilution was a useful way to remedy PCR inhibition. The dilution strategy was, however, not applicable to all natural environmental samples. For example, when marine subsurface sediment samples were tested the copy number of archaeal 16S rRNA genes was 1.04×10(3)copies/g-sediment by digital PCR, whereas real-time PCR only resulted in 4.64×10(2)copies/g-sediment, which was most likely due to an inhibitory effect. The data from this study demonstrated that inhibitory substances had little effect on DNA quantification using microfluidics and digital PCR, and showed the great advantages of digital PCR in accurate quantifications of DNA extracted from various microbial habitats. 相似文献
58.
Gotoh K Inoue K Ogura A Oishi M 《Biochemical and biophysical research communications》2006,348(1):166-169
In-gel competitive reassociation (IGCR) is a method for differential subtraction of polymorphic (RFLP) DNA fragments between two DNA samples of interest without probes or specific sequence information. Here, we applied the IGCR procedure to two cloned mice derived from an F1 hybrid of the C57BL/6Cr and DBA/2 strains, in order to investigate the possibility of genomic alteration in the cloned mouse genomes. Each of the five of the genomic alterations we detected between the two cloned mice corresponded to the "intra-strain" polymorphisms in the C57BL/6Cr and DBA/2 mouse strains. Our result suggests that no severe aberration of genome sequences occurs due to somatic cell nuclear transfer. 相似文献
59.
60.
Adam M. Goldstein 《Evolution》2009,2(3):548-559
A weblog (“blog”) is an publication on the WorldWideWeb in which brief entries are displayed in date order, much like a diary
or journal. I describe the general characteristics of blogs, contrasting blogs with other of WWW formats for self-publishing.
I describe four categories for blogs about evolutionary biology: “professional,” “amateur,” “apostolic,” and “imaginative.”
I also discuss blog networks. I identify paradigms of each category. Throughout, I aim to illuminate blogs about evolutionary
biology from the point of view of a user looking for information about the topic. I conclude that blogs are not the best type
of source for systematic and authoritative information about evolution, and that they are best used by the information-seeker
as a way of identifying what issues are of interest in the community of evolutionists and for generating research leads or
fresh insights on one’s own work.
相似文献
Adam M. GoldsteinEmail: |