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41.
Vincent J. Kalkman Viola Clausnitzer Klaas-Douwe B. Dijkstra Albert G. Orr Dennis R. Paulson Jan van Tol 《Hydrobiologia》2008,595(1):351-363
Larvae of almost all of the 5,680 species of the insect order Odonata (dragonflies and damselflies) are dependent on freshwater
habitats. Both larvae and adults are predators. The order is relatively well studied, and the actual number of species may
be close to 7,000. Many species have small distributional ranges, and are habitat specialists, including inhabitants of alpine
mountain bogs, seepage areas in tropical rain forests, and waterfalls. They are often successfully used as indicators for
environmental health and conservation management. The highest diversity is found in flowing waters in rain forests of the
tropics, the Oriental and Neotropical regions being the most speciose. This paper discusses diversity, summarises the biogeography
of dragonflies in the different biogeographical regions and gives the total number of species and genera per family per biogeographical
region. Examples are given of areas of particular diversity, in terms of areas of endemism, presence of ancient lineages or
remarkable recent radiations but no well-based review of areas with high endemism of dragonflies is available so far. The
conservation status of dragonflies is briefly discussed. Species confined to small remnants of forest in the tropics are most
under threat of extinction by human activities.
Guest editors: E. V. Balian, C. Lévêque, H. Segers and K. Martens
Freshwater Animal Diversity Assessment 相似文献
42.
Bradykinin and (Thr(6))-bradykinin have been identified in the defensive skin secretion of the fire-bellied toad, Bombina orientalis. The homologous cDNAs for both peptides were cloned from a skin library using a 3'- and 5'-RACE strategy. Kininogen-1 (BOK-1) contained an open-reading frame of 167 amino acid residues encoding four repeats of bradykinin, and kininogen-2 (BOK-2) contained an open-reading frame of 161 amino acid residues encoding two repeats of (Thr(6))-bradykinin. Alignment of both precursor nucleotide and amino acid sequences revealed a high degree of structural similarity. These amphibian skin kininogens/preprobradykinins are not biologically analogous to mammalian kininogens. 相似文献
43.
44.
Freezing tolerance was induced in microspore derived embryos of winter Brassica napus cv. Jet neuf by the addition of ABA or mefluidide to the culture media during embryogenesis. Survival after freezing was estimated by culture of frozen-thawed embryos to plantlets. A higher freezing tolerance (50% survival at –15°C) was induced when 50 M ABA or 3.2 M mefluidide was incorporated initially into the medium during embryogenesis at 25°C followed by culture at 2°C for 3 weeks. When embryos were induced in the absence of ABA or mefluidide and maintained at 2°C for even as long as 12 weeks a lower degree of freezing tolerance (10% survival at –15°C) was obtained. Plants regenerated from embryos hardened maximally by a combination of either ABA or MFD with low temperature did not require further vernalization for flowering.Abbreviations ABA
abscisic acid
- MFD
mefluidide
- 2,4-D
2,4-dichlorophenoxyacetic acid
- LT50
killing temperature for 50% of the embryos 相似文献
45.
46.
Atef A. H. Mansour Donald W. Mkay Jon Lien James C. Orr Joseph H. Banoub Nils Øien Garry Stenson 《Marine Mammal Science》2002,18(1):112-120
Measurement of progesterone concentration in blubber was developed as a method to detect pregnancy in minke whales. Progesterone was extracted and quantified from blubber samples of minke whale carcasses by radioimmunoassay. Results showed a highly significant difference (almost 60-fold) between blubber progesterone concentrations of anatomically determined pregnant females versus non-pregnant female or male carcasses. The results of the study suggest that the blubber progesterone concentrations might be used to determine pregnancy status in free-ranging whales. 相似文献
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49.
VLJ Whitehall TD Dumenil DM McKeone CE Bond ML Bettington RL Buttenshaw L Bowdler GW Montgomery LF Wockner BA Leggett 《Epigenetics》2014,9(11):1454-1460
The CpG Island Methylator Phenotype (CIMP) is fundamental to an important subset of colorectal cancer; however, its cause is unknown. CIMP is associated with microsatellite instability but is also found in BRAF mutant microsatellite stable cancers that are associated with poor prognosis. The isocitrate dehydrogenase 1 (IDH1) gene causes CIMP in glioma due to an activating mutation that produces the 2-hydroxyglutarate oncometabolite. We therefore examined IDH1 alteration as a potential cause of CIMP in colorectal cancer. The IDH1 mutational hotspot was screened in 86 CIMP-positive and 80 CIMP-negative cancers. The entire coding sequence was examined in 81 CIMP-positive colorectal cancers. Forty-seven cancers varying by CIMP-status and IDH1 mutation status were examined using Illumina 450K DNA methylation microarrays. The R132C IDH1 mutation was detected in 4/166 cancers. All IDH1 mutations were in CIMP cancers that were BRAF mutant and microsatellite stable (4/45, 8.9%). Unsupervised hierarchical cluster analysis identified an IDH1 mutation-like methylation signature in approximately half of the CIMP-positive cancers. IDH1 mutation appears to cause CIMP in a small proportion of BRAF mutant, microsatellite stable colorectal cancers. This study provides a precedent that a single gene mutation may cause CIMP in colorectal cancer, and that this will be associated with a specific epigenetic signature and clinicopathological features. 相似文献
50.
Claudia G Petersen Fabiana C Massaro Ana L Mauri Joao BA Oliveira Ricardo LR Baruffi Jose G FrancoJr 《Reproductive biology and endocrinology : RB&E》2010,8(1):149