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991.
Maria Heinrich Simona Botti Licia Caprara Wolfgang Arthofer Sabine Strommer Veronika Hanzer Hermann Katinger Assunta Bertaccini Margit Laimer Da Câmara Machado 《Plant Molecular Biology Reporter》2001,19(2):169-179
Phytoplasmas infecting fruit trees are considered quarantine organisms in Europe and North America. Detection often is hampered
by their extremely irregular distribution in host plants. A sensitive, specific and quick diagnostic test would be highly
desirable for routine detection, mainly to avoid using infected planting material. PCR methods require tedious preparation
of DNA; also, the available primers are highly specific and exhibit some homology to chloroplast and plastid DNA. To address
these problems, we compared several DNA preparation protocols for purity of DNA, cost and time required. We also developed
new primers using rDNA sequence information from an Austrian isolate of European Stone Fruit Yellows (ESFY). These primers
operate at high annealing temperatures and, thus, increase the specificity and decrease the risk of false positives. The primers
could reliably detect the European phytoplasmas (AP, ESFY and PD) within a collection of isolates maintained in micropropagated
periwinkle. Thus, they are suitable as general primers for phytoplasma detection. The primers also can be used for strain
identification by direct PCR followed by RFLP analysis as demonstrated with micropropagated fruit tree material. Finally,
an IC-PCR method that uses the primers for AP detection was found very sensitive and suitable for large-scale testing of apple
materialin vivo andin vitro. 相似文献
992.
A electrical conductivity (EC) cell introduced into a porous ceramic cup was developed to continuously sample the solution and measure EC from different growing media. Application of pressure head creates a continuous flow of solution from the growing media tested, into the ceramic cup, and through the EC cell. Continuous recording of the EC was achieved by connecting the EC meter to a data logger. Using two different pressure heads (–5 and –15 kPa) allowed us to observe differences in the EC of the solution extracted that resulted from the different moisture retention of each growing media. After a maximum period of 24 h extracting the solution from different growing media, EC values obtained with the probe were compared with those obtained using paste extracts, saturated with either deionized water or nutrient solution. Results show EC values obtained using the probe with a –15 kPa pressure head were closer to values of EC measured in saturated extracts made with nutrient solution. Using a –5 kPa pressure head, EC values with probe were lower than those obtained by extracts done with nutrient solution, but higher than EC values from saturated extracts made with deionized water. Simultaneous measurements of matric tension and EC show the effect of pressure heads applied in the probe on the water content of growing media. This technique is not destructive (the sampling of growing media is not necessary) and it is possible to obtain EC measurements of solutions continuously. This method of measuring water and salt content of the root environment has potential applications in the greenhouse production of pot plants. Measurements obtained with this method may lead to new information on nutrient uptake by plants and the development of new strategies of managing fertility and irrigation of horticultural crops. 相似文献
993.
A 5.2 kb PstI restriction fragment containing the atpA gene cluster of the plastic genome of the centric diatom Odontella sinensis was cloned. Sequencing revealed a reading frame of 561 bp separating the genes atpF and atpA, which is preceded by a putative ribosome binding site. The third nucleotide of the codon for the last amino acid of atpF is the first nucleotide of the initiation codon of the 561 bp reading frame. The amino acid sequence deduced from the nucleotide sequence of this gene (ntpD) is colinear with δ subunits of different F0F1-ATPases and shows an overall sequence homology of up to 35% when compared with the sequences of cyanobacteria and Cyanophora paradoxa. The results are discussed in context with the evolution of chloroplasts of the chlorophyll-a + b and -a + c lineages, respectively. 相似文献
994.
The process of fusion at the nerve terminal is mediated via a specialized set of proteins in the synaptic vesicles and the presynaptic membrane. Three soluble N-ethylmaleimide-sensitive factor (NSF)-attachment protein receptors (SNAREs) have been implicated in membrane fusion. The structure and arrangement of these SNAREs associated with lipid bilayers were examined using atomic force microscopy. A bilayer electrophysiological setup allowed for measurements of membrane conductance and capacitance. Here we demonstrate that the interaction of these proteins to form a fusion pore is dependent on the presence of t-SNAREs and v-SNARE in opposing bilayers. Addition of purified recombinant v-SNARE to a t-SNARE-reconstituted lipid membrane increased only the size of the globular t-SNARE oligomer without influencing the electrical properties of the membrane. However when t-SNARE vesicles were added to a v-SNARE membrane, SNAREs assembles in a ring pattern and a stepwise increase in capacitance, and increase in conductance were observed. Thus, t- and v-SNAREs are required to reside in opposing bilayers to allow appropriate t-/v-SNARE interactions leading to membrane fusion. 相似文献
995.
Enhancing bioethanol production from delactosed whey permeate by upstream desalination techniques 下载免费PDF全文
Christopher Wagner Christian Benecke Heinrich Buchholz Sascha Beutel 《Engineering in Life Science》2014,14(5):520-529
Industrial cheese whey processing comprises generally the isolation of proteins and lactose, but the economic use for the residual molasses, the so‐called delactosed whey permeate (DWP), is still to be improved. One possibility to maximize valorization and to minimize waste water treatment is the conversion of the remaining lactose in the DWP to ethanol by the yeast Kluyveromyces marxianus. This fermentation process depends strongly on the total ash content of the DWP, as high salt concentrations inhibit yeast metabolism. Here, three different approaches were tested to lower the DWP salt content: (i) simple dilution; (ii) nanofiltration; and (iii) electrodialysis. Lactose consumption, ethanol production and time‐dependent yields were compared between the three methods. A dilution of DWP to 60% v/v led to fermentation taking less than 80 h and yield above 7% AbV (alcohol by volume). After nanofiltration, 7.5% AbV was produced in about 80 h, and after electrodialysis, 11% AbV was produced in about 52 h. On the one hand the technical treatments (nanofiltration and electrodialysis) led to enhanced productivity in the fermentations, but, on the other hand, elaborate and extensive preprocessing is needed. Overall, ethanol production from DWP could be enhanced by prior partial desalination. 相似文献
996.
Víctor Resco de Dios Michael L. Goulden Kiona Ogle Andrew D. Richardson David Y. Hollinger Eric A. Davidson Josu G. Alday Greg A. Barron‐Gafford Arnaud Carrara Andrew S. Kowalski Walt C. Oechel Borja R. Reverter Russell L. Scott Ruth K. Varner Rubén Díaz‐Sierra José M. Moreno 《Global Change Biology》2012,18(6):1956-1970
It is often assumed that daytime patterns of ecosystem carbon assimilation are mostly driven by direct physiological responses to exogenous environmental cues. Under limited environmental variability, little variation in carbon assimilation should thus be expected unless endogenous plant controls on carbon assimilation, which regulate photosynthesis in time, are active. We evaluated this assumption with eddy flux data, and we selected periods when net ecosystem exchange (NEE) was decoupled from environmental variability in seven sites from highly contrasting biomes across a 74° latitudinal gradient over a total of 36 site‐years. Under relatively constant conditions of light, temperature, and other environmental factors, significant diurnal NEE oscillations were observed at six sites, where daily NEE variation was between 20% and 90% of that under variable environmental conditions. These results are consistent with fluctuations driven by the circadian clock and other endogenous processes. Our results open a promising avenue of research for a more complete understanding of ecosystem fluxes that integrates from cellular to ecosystem processes. 相似文献
997.
Glycine transporters: essential regulators of neurotransmission 总被引:1,自引:0,他引:1
Glycine has important neurotransmitter functions at inhibitory and excitatory synapses in the vertebrate central nervous system. The effective synaptic concentrations of glycine are regulated by glycine transporters (GlyTs), which mediate its reuptake into nerve terminals and adjacent glial cells. GlyTs are members of the Na(+)/Cl(-)-dependent transporter family, whose activities and subcellular distributions are regulated by phosphorylation and interactions with other proteins. The analysis of GlyT knockout mice has revealed distinct functions of individual GlyT subtypes in synaptic transmission and provided animal models for two hereditary human diseases, glycine encephalopathy and hyperekplexia. Selective GlyT inhibitors could be of therapeutic value in cognitive disorders, schizophrenia and pain. 相似文献
998.
Jenny Kirsch Kerstin Heinrich Daniel Kage Johannes Glaab Benjamin Grothe Konrad v. Volkmann Toralf Kaiser 《Engineering in Life Science》2022,22(8):550
Aseptic cell sorting is challenging, especially when a flow‐cytometric cell sorter is not operated in a sterile environment. The sheath fluid system of a cell sorter may be contaminated with germs such as bacteria, yeasts, viruses, or fungi. Thus, a regular chemical cleaning procedure is required to prepare a sorter for aseptic cell sorting by flushing the fluidic system. However, this procedure is time consuming, and most importantly, the researcher can never be sure that the cleaning process was successful. Here we present a method in which the sheath fluid of a cell sorter was decontaminated by irradiation with UV‐C light using a flow‐through principle. Using this principle, we were able to achieve a 5 log reduction of bacteria in the sheath fluid. 相似文献
999.
1000.
Isa?Jacoba?Marx Ni?l?van Wyk Salome?Smit Daniel?Jacobson Marinda?Viljoen-Bloom Heinrich?VolschenkEmail author 《Biotechnology for biofuels》2013,6(1):172