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11.
Typical preparation of seed samples for infrared (IR) microspectroscopy involves imbibition of the seed for varying time periods followed by cryosectioning. Imbibition, however, may initiate germination even at 4° C with associated changes in the chemistry of the sample. We have found that it is possible to section seeds that are sufficiently hard, such as soybeans, on a standard laboratory microtome without imbibition. The use of dry sectioning of unimbibed seeds is reported here, as well as a comparison of different mounting media and modes of analysis. Glycerol, Tissue-Tek, and ethanol were used as mounting media, and the quality of the resulting spectra was assessed. Ethanol was the preferred mountant, because it dried quickly with no residue and thus did not interfere with the spectrum of interest. Analysis in transmission mode using barium fluoride windows to hold the samples was compared with transmission-reflection analysis with sections mounted on special infrared-reflecting slides. The two modes of analysis performed well in different regions of the spectrum. The mode of analysis (transmission vs. transmission-reflection) should be based on the components of greatest interest in the sample. 相似文献
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Pradinaud Charlotte Northey Stephen Amor Ben Bare Jane Benini Lorenzo Berger Markus Boulay Anne-Marie Junqua Guillaume Lathuillière Michael J. Margni Manuele Motoshita Masaharu Niblick Briana Payen Sandra Pfister Stephan Quinteiro Paula Sonderegger Thomas Rosenbaum Ralph K. 《The International Journal of Life Cycle Assessment》2019,24(5):960-974
The International Journal of Life Cycle Assessment - While many examples have shown unsustainable use of freshwater resources, existing LCIA methods for water use do not comprehensively address... 相似文献
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ADOLFO AMZQUITA ALBERTINA P. LIMA ROBERT JEHLE LINA CASTELLANOS
SCAR RAMOS ANDREW J. CRAWFORD HERBERT GASSER WALTER H
DL 《Biological journal of the Linnean Society. Linnean Society of London》2009,98(4):826-838
Evolutionary divergence in behavioural traits related to mating may represent the initial stage of speciation. Direct selective forces are usually invoked to explain divergence in mate‐recognition traits, often neglecting a role for neutral processes or concomitant differentiation in ecological traits. We adopted a multi‐trait approach to obtain a deeper understanding of the mechanisms behind allopatric divergence in the Amazonian frog, Allobates femoralis. We tested the null hypothesis that geographic distance between populations correlates with genetic and phenotypic divergence, and compared divergence between mate‐recognition (acoustic) and ecological (coloration, body‐shape) traits. We quantified geographic variation in 39 phenotypic traits and a mitochondrial DNA marker among 125 individuals representing eight populations. Geographic variation in acoustic traits was pronounced and tracked the spatial genetic variation, which appeared to be neutral. Thus, the evolution of acoustic traits tracked the shared history of the populations, which is unexpected for pan‐Amazonian taxa or for mate‐recognition traits. Divergence in coloration appeared uncorrelated with genetic distance, and might be partly attributed to local selective pressures, and perhaps to Batesian mimicry. Divergence in body‐shape traits was low. The results obtained depict a complex evolutionary scenario and emphasize the importance of considering multiple traits when disentangling the forces behind allopatric divergence. ©2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 826–838. 相似文献
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Bacteria growing in biofilms can become up to 1000-fold more resistant to antibiotics and biocides as compared to their planktonic counterparts. As a result of this increased resistance, biofilms and biofilm-related infections cannot be effectively treated with conventional antibiotic therapy. The goal of this study was to determine the efficacy of three neutral pH, super-oxidised solutions (nSOSs, OIS-80, OIS-125, OIS-200, Microcyn Technology) varying in oxychlorine concentration (80, 125 and 200 ppm) against P. aeruginosa grown planktonically and as biofilms. Exposure for 20 s of exponential phase cells to any of the three solutions was sufficient to reduce viability by more than five logs. However, only exposure for 10 min to OIS-125 and OIS-200 for 10 min was sufficient to eradicate stationary phase P. aeruginosa cells. The efficacy of nSOSs on P. aeruginosa biofilms, grown to maturity in continuous flow tube reactors, was determined upon treatment up to 60 min. Viability pre- and post-treatment was determined by CFU counts. The effect of these solutions on P. aeruginosa biofilms and biofilm architecture was further visualised by confocal scanning laser microscopy and quantitatively analysed by COMSTAT. Under these experimental conditions, only OIS-125 and OIS-200 achieved a >3-log reduction and biofilm disaggregation within 30 min of exposure. Because OIS-125 and OIS-200 enhance the disaggregation of biofilms, their use in the treatment of surface-related biofilm infections deserves further investigation. 相似文献
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Data on biopsied, sexed and cryopreserved in vitro produced (IVP) bovine embryos, and their in vivo developmental competence are very limited. Two preliminary studies were conducted before the primary study. In Experiment 1, post-thaw in vitro developmental competence of biopsied and vitrified IVP embryos was evaluated using re-expansion as an endpoint. In Experiment 2, the pregnancy rates of biopsied fresh, frozen or vitrified embryos following single embryo transfer were compared. Since vitrified embryos resulted in a higher pregnancy rate than frozen-thawed embryos, in the primary study (Experiment 3), all IVP embryos were vitrified following biopsy and sexing (by DNA fingerprinting). In Experiment 3, we compared pregnancy initiation and calving results of heifers in the following treatments: 1) artificial insemination (AI); 2) AI plus contralateral transfer of a single embryo (AI + SET); 3) ipsilateral transfer of single embryo (SET); or 4) bilateral transfer of two embryos (DET). Birth weights, gestation lengths and dystocia scores were recorded. In Experiment 1, post-thaw re-expansion rate of biopsied and vitrified embryos was 85% (70/82). In Experiment 2, pregnancy rates (90 d) were 44% (7/16), 23% (3/13), and 50% (7/14) for vitrified, frozen and fresh embryos, respectively (P < 0.10). In Experiment 3, pregnancy rates of AI and SET were 65% (20/31) and 40% (16/40), respectively (P < 0.05). The pregnancy rate of AI + SET was 75% (27/36) with 11 carrying twins, and the pregnancy rate of DET was 72% (26/36) with 10 carrying twins. All AI fetuses were carried to term, but only half the SET fetuses were carried to term. Similar calving rates were observed in the AI + SET and DET groups, 76 and 70%, respectively, of those pregnant at Day 40. Mean birth weight, dystocia score and gestation length of AI calves were not different from those of SET calves. Mean birth weight and dystocia score of single-born calves were greater than those of twin born calves (P < 0.05). These data demonstrate that biopsied IVP bovine embryos can be successfully cryopreserved by vitrification and following post-thaw embryo transfer, acceptable rates of offspring with normal birth weights can be obtained without major calving difficulties. 相似文献
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The genomes of homeothermic (warm-blooded) vertebrates are mosaic
interspersions of homogeneously GC-rich and GC-poor regions (isochores).
Evolution of genome compartmentalization and GC-rich isochores is
hypothesized to reflect either selective advantages of an elevated GC
content or chromosome location and mutational pressure associated with the
timing of DNA replication in germ cells. To address the present controversy
regarding the origins and maintenance of isochores in homeothermic
vertebrates, newly obtained as well as published nucleotide sequences of
the insulin and insulin-like growth factor (IGF) genes, members of a
well-characterized gene family believed to have evolved by repeated
duplication and divergence, were utilized to examine the evolution of base
composition in nonconstrained (flanking) and weakly constrained (introns
and fourfold degenerate sites) regions. A phylogeny derived from amino acid
sequences supports a common evolutionary history for the insulin/IGF family
genes. In cold- blooded vertebrates, insulin and the IGFs were similar in
base composition. In contrast, insulin and IGF-II demonstrate dramatic
increases in GC richness in mammals, but no such trend occurred in IGF- I.
Base composition of the coding portions of the insulin and IGF genes across
vertebrates correlated (r = 0.90) with that of the introns and flanking
regions. The GC content of homologous introns differed dramatically between
insulin/IGF-II and IGF-I genes in mammals but was similar to the GC level
of noncoding regions in neighboring genes. Our findings suggest that the
base composition of introns and flanking regions is determined by
chromosomal location and the mutational pressure of the isochore in which
the sequences are embedded. An elevated GC content at codon third positions
in the insulin and the IGF genes may reflect selective constraints on the
usage of synonymous codons.
相似文献