The corpora lutea proangiogenic state of VEGF system components is turned to antiangiogenic at the later phase of the oestrous cycle in cows

Blood vessel expansion and reduction in the corpus luteum (CL) is regulated by the vascular endothelial growth factor (VEGF) system and linked to the maintenance of the CL. The VEGF system has both angiogenic and antiangiogenic ligands and receptors. Our objective was to evaluate the relationship between the mRNA expression of angiogenic and antiangiogenic members of the VEGF system in the CL, throughout the luteal phase of the oestrous cycle in cows. The CL of 18 cows were collected by transvaginal surgery on days 4, 6, 9, 12, 15 and 18 of the oestrous cycle and the mRNA expression of VEGF system components was evaluated by quantitative real-time PCR. The mRNA expression of VEGF ligands and receptors increased (P<0.05) from the early- and mid-luteal phase (days 4 to 12) reaching its maximum expression on day 15 of the cycle. We found no expression of VEGF164b throughout the cycle. Expression of sVEGFR1 did not change during the oestrous cycle and exceeded that of the VEGFR1 by 100 times. Nonetheless, as VEGFR1 increased, the relationship between the soluble and membrane receptor decreased (P<0.01). In contrast, the expression of VEGFR2 was higher than that of its soluble isoform for all days studied, however, the ratio between the membrane-bound and its soluble counterpart decreased continuously throughout the cycle (P<0.01). Our results show that the expression levels for VEGF ligands, receptors and their antagonistic counterparts are adjusted during CL development and regression, to upregulate angiogenesis early in the oestrous cycle and restrict it at the time of luteolysis.     

Enhancing plasmid transformation efficiency and enabling CRISPR-Cas9/Cpf1-based genome editing in Clostridium tyrobutyricum

Clostridium tyrobutyricum ATCC 25755 is known as a natural hyper-butyrate producer with great potentials as an excellent platform to be engineered for valuable biochemical production from renewable resources. However, limited transformation efficiency and the lack of genetic manipulation tools have hampered the broader applications of this micro-organism. In this study, the effects of Type I restriction-modification system and native plasmid on conjugation efficiency of C. tyrobutyricum were investigated through gene deletion. The deletion of Type I restriction endonuclease resulted in a 3.7-fold increase in conjugation efficiency, while the additional elimination of the native plasmid further enhanced conjugation efficiency to 6.05 ± 0.75 × 10³ CFU/ml-donor, which was 15.3-fold higher than the wild-type strain. Fermentation results indicated that the deletion of those two genetic elements did not significantly influence the end-products production in the resultant mutant ΔRMIΔNP. Thanks to the increased conjugation efficiency, the CRISPR-Cas9/Cpf1 systems, which previously could not be implemented in C. tyrobutyricum, were successfully employed for genome editing in ΔRMIΔNP with an efficiency of 12.5–25%. Altogether, approaches we developed herein offer valuable guidance for establishing efficient DNA transformation methods in nonmodel micro-organisms. The ΔRMIΔNP mutant can serve as a great chassis to be engineered for diverse valuable biofuel and biochemical production.     

Calcium concentration in brains from multiple sclerosis patients

Calcium (Ca) concentrations were studied in the central nervous system (CNS) of four patients with definite multiple sclerosis (MS, average age 49 yr) and five controls (average age 68 yr). The Ca concentration was determined by neutron activation analysis in autopsy samples taken from the 26 subanatomical regions of CNS tissues. Although the mean Ca concentration in the 26 CNS regions combined was higher in the four MS patients than in the controls, the content of white matter was lower. Whether or not this significantly lower Ca concentration found in the white matter of MS patients plays an important role in the demyelinating process remains unclear, although that lower concentration seems not be age dependent, but MS specific.     

Global stability of Gause-type predator-prey systems

In this paper, we present some global stability results obtained from comparison analysis, Bendixson-Dulac criterion or limit cycle stability analysis for the general Gause-type predator-type systems.Research supported in part by a FGIA grant from the Arizona State University Research Fund AMS (MOS) subject classifications. Primary 34C05; secondary 34C25, 92A15.     

Amazonian biodiversity: assessing conservation priorities with taxonomic data

Data from 3991 records of museum collections representing 421 species of plants, arthropods, amphibians, fish, and primates were analyzed with GIS to identify areas of high species diversity and endemism in Amazonia. Of the 472 1 × 1° grid cells in Amazonia, only nine cells are included in the highest species diversity category (43–67 total species) and nine in the highest endemic species diversity category (4–13 endemic species). Over one quarter of the grid cells have no museum records of any of the organisms in our study. Little correspondence exists between the centers of species diversity identified by our collections-based data and those areas recommended for conservation in an earlier qualitative study of Amazonian biodiversity. Museum collections can play a vital role in identifying species-rich areas for potential conservation in Amazonia, but a concerted and structured effort to increase the number and distribution of collections is needed to take maximum advantage of the information they contain.     

Modelling minirhizotron observations to test experimental procedures

In order to help design experiments with minirhizotrons or interpret data from such experiments, a modelling approach is a valuable tool to complement empirical approaches. The general principle of this modelling approach is to calculate and to study the part of a theoretical root system that is intersected by passes through a virtual minirhizotron tube (modelled here as a cylinder). Various outputs can be calculated from this part of the root system, and related to the surrounding root system which is perfectly known, since it has been simulated and stored in a data structure. Therefore, the method involves two levels of modelling that are presented and discussed: the root system architecture of a crop, and the observations that can be achieved with minirhizotron tubes. Illustrations of the method are presented to study the effect of several factors on the rooting depth curves, and to show how images may be calculated to mimic what can actually be viewed from inside the tube. These first results show that the maximum rooting depth curves, as virtually observed in the minirhizotron tube, present large variations and strongly underestimate the maximum rooting depth of the modelled root system (up to 60 cm in average). The underestimation is still more critical when the radius of the tube is lower than 3 cm, and when the tube is close to the vertical (angle lower than 0.2 rad). The use of the 0.9 quantile instead of the average value, for each of the observation dates, leads to a better estimation of the maximum rooting depth.     

Depolarization and Activation of Dihydropyridine-Sensitive Ca2+ Channels Stimulate Inositol Phosphate Accumulation in Photoreceptor-Enriched Chick Retinal Cell Cultures

Abstract: Elevated concentrations of extracellular K⁺ increased inositol phosphate accumulation in primary cultures of chick retinal photoreceptors and multipolar neurons. K⁺-evoked stimulation of inositol phosphate accumulation was greater in photoreceptor-enriched cell cultures than in cultures where multipolar neurons were the predominant cell type. Destroying multipolar neurons, but not photoreceptors, with kainic acid and N -methyl- d -aspartate did not reduce the K⁺-evoked stimulation of inositol phosphate accumulation. Both of these observations indicate that the observed effects occur in photoreceptor cells. The K⁺-evoked stimulation of inositol phosphate accumulation was blocked by omitting Ca²⁺ from the incubation medium or by adding the dihydropyridine-sensitive Ca²⁺-channel antagonists, nitrendipine and nifedipine. Bay K 8644, a dihydropyridine agonist, stimulated inositol phosphate accumulation and enhanced the effect of K⁺. ω-Conotoxin GVIA, an inhibitor of N-type Ca²⁺ channels, had no significant effect on K⁺-stimulated inositol phosphate accumulation. Pretreatment with pertussis toxin neither blocked K⁺-evoked inositol phosphate accumulation nor altered the inhibitory effect of nifedipine. K⁺-evoked inositol phosphate accumulation appears to reflect activation of phosphatidylinositol-specific phospholipase C, as it is inhibited by U-73122. These results indicate that Ca²⁺ influx through voltage-gated, dihydropyridine-sensitive channels activates phospholipase C in photoreceptor inner segments and/or synaptic terminals.     

Mechanoreceptor synapses in the brainstem shape the central representation of touch

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Bifidobacteria-mediated immune system imprinting early in life

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