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991.
Maksymilian Zienkiewicz Tomasz Krupnik Anna Drożak Wioleta Wasilewska Anna Golke Elżbieta Romanowska 《Plant molecular biology》2018,96(1-2):135-149
Key message
We have successfully produced single-cell colonies of C. merolae mutants, lacking the PsbQ’ subunit in its PSII complex by application of DTA-aided mutant selection. We have investigated the physiological changes in PSII function and structure and proposed a tentative explanation of the function of PsbQ’ subunit in the PSII complex.Abstract
We have improved the selectivity of the Cyanidioschyzon merolae nuclear transformation method by the introduction of diphtheria toxin genes into the transformation vector as an auxiliary selectable marker. The revised method allowed us to obtained single-cell colonies of C. merolae, lacking the gene of the PsbQ’ extrinsic protein. The efficiency of gene replacement was extraordinarily high, allowing for a complete deletion of the gene of interest, without undesirable illegitimate integration events. We have confirmed the absence of PsbQ’ protein at genetic and protein level. We have characterized the physiology of mutant cells and isolated PSII protein complex and concluded that PsbQ’ is involved in nuclear regulation of PSII activity, by influencing several parameters of PSII function. Among these: oxygen evolving activity, partial dissociation of PsbV, regulation of dimerization, downsizing of phycobilisomes rods and regulation of zeaxanthin abundance. The adaptation of cellular physiology appeared to favorite upregulation of PSII and concurrent downregulation of PSI, resulting in an imbalance of energy distribution, decrease of photosynthesis and inhibition of cell proliferation.992.
993.
Amal Laakili Bouchra Belkadi Leila Medraoui Mohammed Alami Chaimaa Yatrib Ouafae Pakhrou Mohamed Makhloufi Salwa El Antry Ahmed Laamarti Abdelkarim Filali-Maltouf 《Physiology and Molecular Biology of Plants》2018,24(4):643-654
Morocco is one of the most important regions of the world in terms of Quercus suber L. number and variation. This species is in decline due to several factors, which can lead to permanent loss of this resource. It would be essential to evaluate the genetic diversity in order to conserve maximum genetic variability of this species. The genetic diversity and differentiation of 16 sites from five regions representing the entire range of Moroccan Cork Oak were assessed. Twenty-three ISSR primers used generated 985 polymorphic fragments with an average of 42.8 bands per primer and showed 100% of polymorphism. The 173 individuals revealed a moderate level of genetic diversity at species level (I?=?0.27, He?=?0.161). The AMOVA showed that the highest level of diversity occurred within populations (64%), this was also confirmed by the coefficient of differentiation (Gst?=?0.47). The estimated gene flow (Nm?=?0.56) and the Mantel test revealed a significant correlation between geographic and genetic diversity (r?=?0.266; p?=?0.001). This genetic structure was further shown by the topology of the UPGMA, sPCA and STRUCTURE analysis. In addition, a core collection of 34 genotypes was established representing the essential diversity detected. This research advocates populations and individuals to preserve in order to improve and conserve this resource in the future. 相似文献
994.
Y. Bouargalne R. Ben Mrid R. El Omari M. Nhiri 《Russian Journal of Plant Physiology》2018,65(6):824-832
Sorghum (Sorghum bicolor (L.) Moench) is a species of great socio-economic and ecological importance for countries in arid and semi-arid climate. In C4 plants like sorghum, phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) plays a key role in seed development and germination. In this work, the PEPC activity shows an increase followed by a decrease at the early and later stages of maturation, respectively. In germinating seeds, the PEPC activity quickly increases after soaking. The L-malate test and the ratio of PEPC activity determined at pH 8.0 and 7.1, indicates, that PEPC is phosphorylated at the early stages of maturation then becomes dephosphorylated at the later stages and during seed germination, PEPC takes back its phosphorylated form. The determination of the affinity constant showed different KM depending on the seed developmental stage. As there is no PEPC-C4 isoform in developing sorghum seeds, this result indicates that the different KM observed during seed maturation could be a result of a post-translational regulation such as phosphorylation or ubiquitination of a pre-existing isoform. This regulation enhances the PEPC activity at early stages of seed development. 相似文献
995.
S. Mirzaei M. El Yacoubi S. Garcia-Salicetti J. Boudy C. Kahindo V. Cristancho-Lacroix H. Kerhervé A.-S. Rigaud 《IRBM》2018,39(6):430-435
Background
The goal of this work is to develop a non-invasive method in order to help detecting Alzheimer's disease in its early stages, by implementing voice analysis techniques based on machine learning algorithms.Methods
We extract temporal and acoustical voice features (e.g. Jitter and Harmonics-to-Noise Ratio) from read speech of patients in Early Stage of Alzheimer's Disease (ES-AD), with Mild Cognitive Impairment (MCI), and from a Healthy Control (HC) group. Three classification methods are used to evaluate the efficiency of these features, namely kNN, SVM and decision Tree. To assess the effectiveness of this set of features, we compare them with two sets of feature parameters that are widely used in speech and speaker recognition applications. A two-stage feature selection process is conducted to optimize classification performance. For these experiments, the data samples of HC, ES-AD and MCI groups were collected at AP-HP Broca Hospital, in Paris.Results
First, a wrapper feature selection method for each feature set is evaluated and the relevant features for each classifier are selected. By combining, for each classifier, the features selected from each initial set, we improve the classification accuracy by a relative gain of more than 30% for all classifiers. Then the same feature selection procedure is performed anew on the combination of selected feature sets, resulting in an additional significant improvement of classification accuracy.Conclusion
The proposed method improved the classification accuracy for ES-AD, MCI and HC groups and promises the effectiveness of speech analysis and machine learning techniques to help detect pathological diseases. 相似文献996.
Colicin N is a bacteriocin that kills sensitive Escherichia coli cells. After binding to the cell surface-exposed receptor, a short period exists when a significant number of the cell-associated colicin N molecules are sensitive to external enzymes. Two colicin N populations are discriminated by proteases: the susceptible pool bound to OmpF porin on the cell surface and another population corresponding to protease-inaccessible colicin N. During translocation, colicin N reaches the periplasmic space and proteolytic cleavage of the colicin occurs only when the outer membrane barrier is permeabilized. 相似文献
997.
High level of genetic differentiation for allelic richness among populations of the argan tree [Argania spinosa (L.) Skeels] endemic to Morocco 总被引:6,自引:0,他引:6
A. El Mousadik R. J. Petit 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(7):832-839
Genetic diversity at nine isozyme loci was surveyed in an endangered tree species, the argan tree, endemic to south-western Morocco. The species is highly diverse (3.6 alleles/locus) with populations strongly differentiated from each other (F
ST=0.25). This example is used to illustrate a method for standardizing measures of allelic richness in samples of unequal sample sizes, which was developed for the estimation of the number of species and relies on the technique of rarefaction. In addition, it is shown that the measure of subdivision,
ST, obtained when allelic richness is used in place ofh (Nei's index of diversity), is much larger than the F
ST [e.g.
ST(40)=0.52, where (40) indicates the specified sample used to estimate the allelic richness]. This suggests that rare alleles (which strongly influence measures of allelic richness) have a more scattered distribution than more frequent ones, a result which raises special conservation issues for the argan tree. 相似文献
998.
Callus cultures of Solanum paludosum were established from roots, hypocotyles, cotyledons and leaf limbs of plantlets cultivated in sterile conditions on a Murashige and Skoog's modified medium. Non organogenous calluses were obtained with addition of BA or kinetin (10-5M to 10-6M) as the cytokinin and 2,4-d or NAA (10-5M to 10-6M) as the auxin. These calluses permitted the establishment of a cell suspension culture with BA (10-6M) and 2,4-d (10-6M). Zeatin (10-6M) with IAA (10-6M) gave rise to organogenous calluses. These organogenous callus cultures developed multiple shoots which either proliferated if they were cultivated on a medium containing zeatin with IAA or IBA or were able to regenerate into whole plants when zeatin was used as the only hormone. The different plant material produced solamargine, the main steroidal glycoalkaloid present in the unripe fruits. The best production was obtained with the fruits of regenerated plants from organogenous callus cultures after reintroduction of these plants in their brasilian biotope. The solamargine content of the two types of plant materials was about 0.06% and 2.5% (dry weight) respectively for the callus cultures and the fruits from in vitro plants. The fruits were harvested a year after the beginning of the plantlet regeneration step.Abbreviations HPTLC
high performance thin layer chromatography
- HPLC
high performance liquid chromatography
- 2,4-d
2,4-dichlorophenoxyacetic acid
- BA
benzylaminopurine
- IAA
3-indolebutyric acid
- NAA
-naphthaleneacetic acid
- IBA
3-indolebutyric acid
- IPA
isopentenyladenine 相似文献
999.
P. Berrebi M. M. Kraiem † I. Doadrio ‡ S. El Gharbi § G. Cattaneo-Berrebi 《Journal of fish biology》1995,47(5):850-864
Enzyme electrophoresis on horizontal starch gel was carried out on 356 barbel individuals. The sampling comprised 278 individuals of the species Barbus callensis from 10 rivers in Tunisia. The other individuals belonged to reference species (outgroups) from France and Morocco. An ecological study was also carried out on Tunisian rivers. The results show a clear differentiation of the two samples from northwestern Tunisia, which was only partly correlated with ecological characteristics of the rivers they inhabit. There is no genetic cline, but rather a discontinuity between populations in the northwestern-most watershed and all the other Tunisian populations. This differentiation probably has a paleohistoric origin not only related to adaptation to ecological conditions but also to difficulties in colonizing the watersheds. The results do not indicate clearly a colonization direction for the genus Barbus in North Africa. Analysis of the Algerian populations would appear to be indispensable. Lastly, in contrast with the usual taxonomy, Morocco and Tunisia are populated by two closely related species, but B. callensis should remain the name of the Tunisian species, which was the first to be described in the small El Kebir basin, a river that flows from Tunisia to Algeria. 相似文献
1000.