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511.
This study examined the relationship between the distance of axotomy and the death of injured retinal ganglion cells (RGCs) in adult hamsters and the relationship of cytochrome c and caspase-3 on the death pathway of RGCs. The left optic nerve (ON) of adult hamsters was transected either at 1 or 3 mm away from the optic disc, and retrogradely labeled with Flurogold on the ON stump. After a predetermined period of postoperative time, the surviving RGCs were counted by retina flat-mount, and the activation of cytochrome c and caspase-3 were investigated by immunohistochemistry. Cell loss was found to be much faster (P < 0.01), more cells with cytochrome c were observed (P < 0.05) and the activation of caspase-3 was earlier when ON was transected 1 mm away from the optic disc than when was transected 3 mm away from the optic disc. Distance of axotomy affects the axotomized cell death rate where more RGCs died when the ON transection was applied closer to the eye. The timing of activation of caspase-3 in the RGCs may be linked to the distance of axotomy.Special issue dedicated to Dr. Lawrence F. Eng 相似文献
512.
Jaime Gongora Rebecca E. Cuddahee Fabrícia Ferreira do Nascimento Christopher J. Palgrave Stewart Lowden Simon Y. W. Ho Denbigh Simond Chandramaya Siska Damayanti Daniel James White Wee Tek Tay Ettore Randi Hans Klingel Clara J. Rodrigues‐Zarate Kari Allen Chris Moran Greger Larson 《Zoologica scripta》2011,40(4):327-335
Gongora, J., Cuddahee, R. E., do Nascimento, F. F., Palgrave, C. J., Lowden, S., Ho, S. Y. W., Simond, D., Damayanti, C. S., White, D. J., Tay, W. T., Randi, E., Klingel, H., Rodrigues‐Zarate, C. J., Allen, K., Moran, C. & Larson, G. (2011). Rethinking the evolution of extant sub‐Saharan African suids (Suidae, Artiodactyla). —Zoologica Scripta, 40, 327–335. Although African suids have been of scientific interest for over two centuries, their origin, evolution, phylogeography and phylogenetic relationships remain contentious. There has been a long‐running debate concerning the evolution of pigs and hogs (Suidae), particularly regarding the phylogenetic relationships among extant Eurasian and African species of the subfamily Suinae. To investigate these issues, we analysed the mitochondrial and nuclear DNA sequences of extant genera of Suidae from Eurasia and Africa. Molecular phylogenetic analyses revealed that all extant sub‐Saharan African genera form a monophyletic clade separate from Eurasian suid genera, contradicting previous attempts to resolve the Suidae phylogeny. Two major sub‐Saharan African clades were identified, with Hylochoerus and Phacochoerus grouping together as a sister clade to Potamochoerus. In addition, we find that the ancestors of extant African suids may have evolved separately from the ancestors of modern day Sus and Porcula in Eurasia before they colonised Africa. Our results provide a revision of the intergeneric relationships within the family Suidae. 相似文献
513.
Silvana Gaudieri Chanvit Leelayuwat Guan K. Tay David C. Townend Roger L. Dawkins 《Journal of molecular evolution》1997,45(1):17-23
The major histocompatibility complex (MHC) consists of polymorphic frozen blocks (PFBs) that are linked to form megabase
haplotypes. These blocks consist of polymorphic sequences and define regions where recombination appears to be inhibited.
We have been able to show, using a highly polymorphic sequence centromeric of HLA-B (within the beta block), that PFBs are conserved and contain specific insertions/deletions and substitutions that are the
same for individuals with the same MHC haplotype but that differ between at least most different haplotypes. A sequence comparison
between ethnic-specific haplotypes shows that these sequences have remained stable and predate the formation of these haplotypes.
To determine whether the same conserved block has been involved in the generation of multiple haplotypes, we compared the
block typing profiles of different ethnic specific haplotypes. Block typing profiles have previously been shown to be identical
in individuals with the same MHC haplotype but, generally, to differ between different haplotypes. It was found that some
PFBs are common to more than one haplotype, implying a common ancestry. Subsequently, haplotypes have been generated by the
shuffling and exchange of these PFBs. The regions between these PFBs appear to permit the recombination sites and therefore
could be expected to exhibit either low polymorphism or a localized ``hotspot.'
Received: 20 January 1997 / Accepted: 11 March 1997 相似文献
514.
The motor, sensory, and postganglionic sympathetic neurons forming the left ulnar and right radial nerves of long-tailed macaques (Macaca fascicularis) and pigtailed macaques (Macaca nemestrina) were localized by the horseradish peroxidase method of tracing neuronal connections. The ulnar and radial motoneurons formed a longitudinal column of variable extent in the lateral part of the ventral horn. In most animals, the ulnar motoneurons extended between the caudal ends of the C7 and T1 segments; the radial motoneurons extended between the rostral level of the C4 and the middle part of T1 segments. Although there were areas of overlap in the spinal distribution of ulnar and radial motoneurons, the ulnar motoneurons were located more dorsally and dorsolaterally than were the radial motoneurons. In most animals, labelled sensory neurons whose axons run with the ulnar nerve occurred in the C8–T4 dorsal root ganglia, and those whose axons run with the radial nerve occurred in the C5–T3 ganglia. The radial sympathetic neurons were distributed in stellate through T7 paravertebral sympathetic ganglia, and the ulnar sympathetic neurons were distributed in stellate through T4 paravertebral sympathetic ganglia. Though the motor, sensory, and sympathetic neurons forming the ulnar and radial nerves had wide segmental distributions, all showed peak frequencies in two segments. The cross-sectional areas of the motor, sensory, and postganglionic sympathetic neurons forming the radial and ulnar nerves were measured in the animal that showed the greatest amount of labelling for each nerve. The ulnar and radial motoneurons had a similar range of sizes, with cross-sectional areas between 120 and 2,160 μm2. Most were smaller than 900 μm2. The sensory neurons forming the ulnar and radial nerves also displayed a similar range of sizes, measuring between 120 and 3,360 μm2 in cross-sectional area. Most neurons measured between 201 and 800 μm2. The ulnar sympathetic neurons measured between 120 and 840 μm2, and the radial neurons between 120 and 2,120 μm2. In both cases, most neurons measured between 120 and 600 μm2. The mean cross-sectional area for the radial sympathetic neurons was, however, larger than that for the ulnar sympathetic neurons. 相似文献
515.
Tay Tiong-Lee Stephen Ivanov Volodymyr Kim In Soo Feng Lin Tay Joo-Hwa 《World journal of microbiology & biotechnology》2001,17(6):583-589
16S rRNA-targeted oligonucleotide probes for Bacteria (Eub338) and Archaea (Arc915) were used for whole-cell, fluorescence in situ hybridization (FISH) to quantify the ratio of these microbial groups in an anaerobic digester. The quantity of specifically bound (hybridized) probe was measured by fluorescence spectrometry and evaluated by analysing the dissociation curve of the hybrids, by the measurement of the binding with a nonsense probe, and by the competitive inhibition of the binding of the labelled probe by the corresponding unlabelled probe. Specific binding of oligonucleotide probes with the biomass of anaerobes was 40–50% of their total binding. The ratio of Arc915 and Eub338 probes hybridized with rRNAs of the cells in anaerobic sludge was 0.50. Measurement of FISH by fluorescence spectrometry appears to be a suitable method for quantification of the microbial community of anaerobes. 相似文献
516.
517.
Denaturing gradient gel electrophoresis (DGGE) of a PCR-amplified region of the mitochondrial DNA (mtDNA) including a large part of the cytochrome b gene revealed four haplotypes among worker ants from 75 colonies of the queenless ant Rhytidoponera sp. 12. The DGGE results were checked by sequencing examples of the haplotypes; all changes were transitions and two haplotypes differed by only a single substitution. Previous work (e.g. Crozier et al. 1984) showed that intranest relatedness is low for nuclear genes yet neighbouring nests are related; gene flow via winged males appeared the best explanation for this phenomenon. Two mtDNA haplotypes were found in 34.7% of the colonies studied, showing that female movement also occurs between nests. Migration of mated individuals on such a large scale when the number of reproductives is relatively small is unexpected (Crozier & Pamilo 1996). An observed tendency to clumping of the haplotypes is in accordance with the wingless nature of the female dispersers. 相似文献
518.
Xiaojin Wei Zhendi Yang Yuxin Wang See Leng Tay Wei Gao 《Applied microbiology and biotechnology》2014,98(14):6265-6274
Many diseases spread due to the bacterial infections, which cause significant economic and personal losses. Contact with infected surfaces is likely to catch infections. Hence, antimicrobial surfaces play an important role in public sectors that can prevent the spreading of disease and infection. Coatings on contact surfaces have been used to provide antimicrobial function. Copper (Cu), as one of the commonly used metals, has long been known to possess germ-killing properties. However, metallic Cu or Cu coatings have not been widely used for the purposes of antimicrobial due to the heavy weight, relatively high cost, limited corrosion resistance and low compatibility of the metal with substrates of non-metallic materials. We have recently developed a polymer-based coating system containing mixtures of fine particles of Cu and Cu salt, which provides excellent antimicrobial properties. The results indicate that the coating with embedded fine Cu salt showed higher antimicrobial property than the coating with only Cu due to the release of more Cu ions. The elimination of 106 bacteria by contacting the polymer-Cu coatings needs 8 h, while contacting with the polymer-CuCl2 coatings took only 20 min to kill the same amount of bacteria. We have also used transmission electron microscopy and synchrotron infrared microscopy technique to study the degradation of bacterial cell membrane to understand the mechanism of the antimicrobial function of Cu coating. 相似文献
519.
Bee-Yong Tay Bhadravathi Eswara Lokesh Chow-Yang Lee Kumar Sudesh 《World journal of microbiology & biotechnology》2010,26(6):1015-1024
The continuous quest for bacterial strains capable of accumulating polyhydroxyalkanoate (PHA) utilizing cheaper and renewable
carbon source prompted us to explore newer and diverse environments like the gut of termites. Among the bacterial strains
isolated from the gut of higher termite Macrotermes carbonarius, three strains were found to accumulate PHA, as observed by microscopic studies and PHA production experiments. Among them,
strain MC1 with rapid growth and higher PHA accumulation was selected for further studies. API kit-50 CHB and 16S rRNA gene
sequence analysis results indicated the strain to have 99% homology with Bacillus megaterium and Bacillus flexus.
Bacillus sp. MC1 was able to accumulate PHA during the growth phase utilizing different carbon sources like glucose, fructose, sodium
acetate, sodium valerate and 1,4-butanediol. Gas chromatography analysis of the polymer has shown it to be basically composed
of poly (3-hydroxybutyrate) (PHB). Growth associated PHB biosynthesis was best in the presence of sodium acetate with 39 wt%
after 16 h of cultivation. Though previous studies provided evidence confirming the presence of PHA producing bacteria in
termite gut, isolation and characterization of these strains in pure culture has not been documented yet. Presence of other
morphotypes in the termite gut with PHA like granular inclusions was evident from the transmission electron microscopy studies.
This is a novel report and shows the feasibility of using potent strains capable of utilizing lignocellulosic degradation
products as a renewable carbon source for the production of PHA in the future. 相似文献
520.
The frequency of deletional alpha-thalassaemia in a Javanese population sample (n = 103) was investigated at three restriction sites of the alpha-globin gene (BamHI, BglII and RsaI). The overall gene frequency of alpha+ deletional thalassaemia was found to be very low (0.03). Leftward (-alpha 4.2) and rightward (-alpha 3.7) deletions and triplicated genes were present in equal frequency (0.015 and 0.005, respectively). 相似文献