Déterminisme de la reproduction sexuée de Phaeosphaeria (Leptosphaeria) nodorum, agent de la septoriose du blé. I. Hétérothallisme et rôle des microspores

1991 ◽  
Vol 69 (1) ◽  
pp. 95-99 ◽  
Author(s):  
P. Halama ◽  
L. Lacoste

Recently identified conditions for in vitro perithecia formation made it possible to demonstrate the existence of previously suggested heterothallism in Phaeosphaeria nodorum. Of the 28 possible pairwise crosses between the eight cultures derived from the spores of a single ascus, 9 were fertile, whereas none of the cultures ever produced fertile perithecia on their own. This result is smaller than the one obtained in classical bipolar heterothallism and suggests the existence of another incompatibility mechanism. The growth and the colour of mycelia derived from eight single ascospores from the same ascus seem to cosegregate with the factor for heterothallism. The formation of microspores in colonies from single ascospores indicates that they may play a role in the formation of perithecia. Used for fertilization, these microspores showed that they were able to bring the complementary nucleus, thus enabling the differentiation of perithecia. However, they are able to germinate and do not behave strictly as spermatia. Key words: Phaeosphaeria, Leptosphaeria nodorum, heterothallism, microspores.

1992 ◽  
Vol 70 (8) ◽  
pp. 1563-1569 ◽  
Author(s):  
P. Halama ◽  
L. Lacoste

Perithecial formation of Phaeosphaeria nodorum is obtained in vitro on sterilized wheat straws, under strict conditions of light and temperature. The absence of any reproductive form in the dark indicates photoinduction. The different parameters of light (duration, quality, and intensity) influence perithecial morphogenesis. A 12-h photoperiod, near ultraviolet light (300 nm < λ < 400 nm), and intensities of 400 and 600 μW/cm2 are the most favourable conditions for perithecial differentiation. The perithecial production occurs best at 10 °C, is markedly reduced at 14 °C, and absent above 14 °C. Light and temperature have a sequential influence on the successive stages of perithecial development. Whereas primordial formation is photoinhibited and cryostimulated, transformation to the early stage of perithecial development is photoinduced and not affected by temperatures of 10 and 18 °C. The subsequent stages up to ascogenesis are photostimulated and cryoinduced, and ascosporogenesis is photoindependent and cryostimulated. Key words: Phaeosphaeria, Leptosphaeria nodorum, perithecia, light, temperature.


1992 ◽  
Vol 70 (7) ◽  
pp. 1401-1408 ◽  
Author(s):  
P. Halama ◽  
A. Parguey-Leduc ◽  
L. Lacoste

The reproductive organs of one of the pathogens responsible for the septoria diseases of wheat were studied from cultures. There are two types of pycnidia for the asexual stage (one belongs to Septoria nodorum Berk. (=Stagonospora nodorum (Berk.) Castellani & Germano); the other is microconidial) and pseudothecia for the teleomorph: Phaeosphaeria nodorum (E. Müller) Hedjaroude (=Leptosphaeria nodorum E. Müller). The latter are differentiated from glomerular primordia, and their development is typical of an ascolocular pyrenomycete, with a perilocular layer generating descending pseudoparaphyses and periphyses lining the ostiolar cavity. The asci, with a "Jack-in-the-box" dehiscence, are bitunicate. Key words: Phaeosphaeria nodorum, Leptosphaeria, ontogeny and structure, pseudothecia, pycnidia.


2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Hongfang Ma ◽  
Rui Li ◽  
Longguang Jiang ◽  
Songlin Qiao ◽  
Xin-xin Chen ◽  
...  

AbstractPorcine reproductive and respiratory syndrome (PRRS) is a serious disease burdening global swine industry. Infection by its etiological agent, PRRS virus (PRRSV), shows a highly restricted tropism of host cells and has been demonstrated to be mediated by an essential scavenger receptor (SR) CD163. CD163 fifth SR cysteine-rich domain (SRCR5) is further proven to play a crucial role during viral infection. Despite intense research, the involvement of CD163 SRCR5 in PRRSV infection remains to be elucidated. In the current study, we prepared recombinant monkey CD163 (moCD163) SRCR5 and human CD163-like homolog (hCD163L1) SRCR8, and determined their crystal structures. After comparison with the previously reported crystal structure of porcine CD163 (pCD163) SRCR5, these structures showed almost identical structural folds but significantly different surface electrostatic potentials. Based on these differences, we carried out mutational research to identify that the charged residue at position 534 in association with the one at position 561 were important for PRRSV-2 infection in vitro. Altogether the current work sheds some light on CD163-mediated PRRSV-2 infection and deepens our understanding of the viral pathogenesis, which will provide clues for prevention and control of PRRS.


2021 ◽  
Vol 11 (12) ◽  
pp. 5612
Author(s):  
Stefano Fanali ◽  
Margherita Tumedei ◽  
Pamela Pignatelli ◽  
Alessandra Lucchese ◽  
Francesco Inchingolo ◽  
...  

Background: Implant primary stability can be affected by several factors related to implant macrogeometry, local anatomy, and surgical techniques. The aim of this research was to study primary stability on polyurethane foam sheets of wide-threaded implant design compared to narrow-threaded implants. Materials and methods: Two different implant designs were positioned on D3 density polyurethane blocks in a standardized environment: the wide-threaded implant and the narrow-threaded implant, for a total of 160 specimens. Moreover, for each group, two different sizes were considered: 3.8mm × 12mm and 4.8mm × 12 mm. The insertion torque (IT) values, the removal strength (RT), and the Periotest analyses were evaluated. Results: A significantly higher IT and RT was reported for wide-threaded implants and two-stage implants (p < 0.01), compared to the narrow-threaded implants. The diameters seemed to provide a significant effect on the primary stability for both implants’ geometry (p < 0.01). A higher mean of the one-stage implant was evident in the Periotest measurements (p < 0.01). Conclusions: Both of the implants showed sufficient stability in polyurethane artificial simulation, while the wide-threaded implant design showed a higher primary stability on alveolar cancellous synthetic bone in vitro. Additionally, the prosthetic joint connection seemed to have a determinant effect on Periotest analysis, and the one-stage implants seemed to provide a high stability of the fixture when positioned in the osteotomy, which could be important for the immediate loading protocol.


Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 77
Author(s):  
Elena O. Vidyagina ◽  
Nikolay N. Kharchenko ◽  
Konstantin A. Shestibratov

Axillary buds of in vitro microshoots were successfully frozen at –196 °C by the one-step freezing method using the protective vitrification solution 2 (PVS2). Microshoots were taken from 11 transgenic lines and three wild type lines. Influence of different explant pretreatments were analyzed from the point of their influence towards recovery after cryopreservation. It was found out that the use of axillary buds as explants after removal of the apical one increases recovery on average by 8%. The cultivation on growth medium of higher density insignificantly raises the regenerants survival rate. Pretreatment of the osmotic fluid (OF) shows the greatest influence on the survival rate. It leads to the increase in survival rate by 20%. The cryopreservation technology providing regenerants average survival rate of 83% was developed. It was based on the experimental results obtained with explant pretreatment. Incubation time in liquid nitrogen did not affect the explants survival rate after thawing. After six months cryostorage of samples their genetic variability was analyzed. Six variable simple sequence repeat (SSR) loci were used to analyze genotype variability after the freezing-thawing procedure. The microsatellite analysis showed the genetic status identity of plants after cryopreservation and of the original genotypes. The presence of the recombinant gene in the transgenic lines after cryostorage were confirmed so as the interclonal variation in the growth rate under greenhouse conditions. The developed technique is recommended for long-term storage of various breeding and genetically modified lines of aspen plants, as it provides a high percentage of explants survival with no changes in genotype.


2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Fabienne Archer ◽  
Alexandra Bobet-Erny ◽  
Maryline Gomes

AbstractThe number and severity of diseases affecting lung development and adult respiratory function have stimulated great interest in developing new in vitro models to study lung in different species. Recent breakthroughs in 3-dimensional (3D) organoid cultures have led to new physiological in vitro models that better mimic the lung than conventional 2D cultures. Lung organoids simulate multiple aspects of the real organ, making them promising and useful models for studying organ development, function and disease (infection, cancer, genetic disease). Due to their dynamics in culture, they can serve as a sustainable source of functional cells (biobanking) and be manipulated genetically. Given the differences between species regarding developmental kinetics, the maturation of the lung at birth, the distribution of the different cell populations along the respiratory tract and species barriers for infectious diseases, there is a need for species-specific lung models capable of mimicking mammal lungs as they are of great interest for animal health and production, following the One Health approach. This paper reviews the latest developments in the growing field of lung organoids.


2020 ◽  
Vol 44 (43) ◽  
pp. 18858-18866
Author(s):  
Kavanal P. Prasanthkumar ◽  
P. K. Sajith ◽  
Beena G. Singh

Using in vitro methods, the one electron oxidations of kynurenic acid and its efficacy in scavenging lipid peroxidation have been demonstrated.


1998 ◽  
Vol 22 ◽  
pp. 306-308
Author(s):  
M. D. Carro ◽  
E. L. Miller

The estimation of rumen microbial protein synthesis is one of the main points in the nitrogen (N)-rationing systems for ruminants, as microbial protein provides proportionately 0.4 to 0.9 of amino acids entering the small intestine in ruminants receiving conventional diets (Russell et al., 1992). Methods of estimating microbial protein synthesis rely on marker techniques in which a particular microbial constituent is related to the microbial N content. Marker : N values have generally been established in mixed bacteria isolated from the liquid fraction of rumen digesta and it has been assumed that the same relationship holds in the total population leaving the rumen (Merry and McAllan, 1983). However, several studies have demonstrated differences in composition between solid-associated (SAB) and fluid-associated bacteria in vivo (Legay-Carmier and Bauchart, 1989) and in vitro (Molina Alcaide et al, 1996), as well in marker : N values (Pérez et al., 1996). This problem could be more pronounced in the in vitro semi-continuous culture system RUSITEC, in which there are three well defined components (a free liquid phase, a liquid phase associated with the solid phase and a solid phase), each one having associated microbial populations.The objective of this experiment was to investigate the effect of using different bacterial isolates (BI) on the estimation of microbial production of four different diets in RUSITEC (Czerkawski and Breckenridge, 1977), using (15NH4)2 SO4 as microbial marker, and to assess what effects any differences would have on the comparison of microbial protein synthesis between diets.This study was conducted in conjunction with an in vitro experiment described by Carro and Miller (1997). Two 14-day incubation trials were carried out with the rumen simulation technique RUSITEC (Czerkawski and Breckenridge, 1977). The general incubation procedure was the one described by Czerkawski and Breckenridge (1977) and more details about the procedures of this experiment are given elsewhere (Carro and Miller, 1997).


1982 ◽  
Vol 62 (3) ◽  
pp. 751-757 ◽  
Author(s):  
J. A. BASARAB ◽  
R. T. BERG ◽  
J. R. THOMPSON

The in vitro glucose consumption and lactic acid production by erythrocytes from 20 cattle of a Beef Synthetic (SY) breed group and 25 cattle of a double-muscled (DM) breed group were determined. There were three age groups and two sexes within each breed group. Animals within the DM breed group were categorized as either phenotypically normal- to moderate-muscled (DM carriers) or extreme-muscled (extreme DM) based on the phenotypic expression of the double-muscling trait and on their breeding history. Both DM phenotypes had higher (P < 0.01) erythrocyte glucose consumption and lactic acid production than normal-muscled, noncarrier cattle of the SY breed group. Extreme DM cattle were not different (P > 0.05) in either their erythrocyte glucose consumption or lactic acid production compared with DM carriers. No difference (P > 0.05) due to breed or phenotype was observed in the molar ratio of lactic acid produced to glucose consumed by erythrocytes. These results suggest that carriers of the Double Muscled Syndrome, regardless of phenotypic expression of the double-muscling trait, have a higher rate of erythrocyte glycolysis than normal cattle. Key words: Cattle, double muscled, erythrocyte, glucose, lactic acid


1974 ◽  
Vol 52 (10) ◽  
pp. 838-844 ◽  
Author(s):  
Mark Nwagwu ◽  
John Lianga

As a prelude to an analysis of the dependence of muscle protein synthesis on aminoacyl tRNA's, we have investigated the rates of seryl-tRNA formation, in vitro, by aminoacylating systems isolated from 11-, 14-, and 17-day chick embryonic muscle. The results show that the combination of 14-day tRNA and 14-day aminoacyl synthetase is the most efficient in seryl-tRNA formation. We have also studied the qualitative and quantitative changes in seryl-tRNA prepared from 11-, 14-, and 17-day embryonic chick muscle by chromatography of seryl-tRNA on benzoylated DEAE-cellulose columns. The results show that, although there are no qualitative differences in the chromatographic patterns of seryl-tRNA from the different ages, there are significant quantitative differences between the patterns for 11-day and 17-day seryl-tRNA on the one hand, and the pattern for 14-day seryl-tRNA on the other.


Sign in / Sign up

Export Citation Format

Share Document