Aspects infrastructuraux des altérations des anthères de Silene dioica parasitées par Ustilago violacea

1980 ◽  
Vol 58 (4) ◽  
pp. 405-415 ◽  
Author(s):  
Jean-Claude Audran ◽  
Mekinto Batcho
Keyword(s):  
Early Stage ◽  
Structural Characteristics ◽  
Silene Dioica ◽  
Histological Changes ◽  
Ustilago Violacea ◽  
Dikaryotic Mycelium ◽  
Sporogenous Tissue ◽  
Superficial Tissues

The structural characteristics of the sporogenous and parietal tissues of healthy anthers of Silene dioica (L.) Clairv. (Caryophyllaceae) are described as well as those of anthers infected by Ustilago violacea (Pers.) Rouss. (Ustilaginales). In infected anthers, the invading dikaryotic mycelium grew intercellularly and very rarely penetrated the cells. The pathogen stopped stamen histogenesis at an early stage, causing necrosis specifically of the sporogenous tissue either directly or following hypertrophy. Five stages were distinguished during the histological modifications leading to anther destruction. (1) First, the mycelium developed in the anther filament and spread throughout the superficial tissues of the anther without causing histological changes in the anther. (2) Then, some sporogenous cells began to show necrosis and formed compact masses. (3) An increasing number of sporogenous cells became necrotic following strong vacuolisation and hypertrophy. (4) Hyphae grew profusely in the necrotic mass of sporogenic cells. (5) Finally, the fungus produced teliospores which filled the sporangial cavity.

scholarly journals Microsporogenesis and pollen grains in Silene dioica (L.) Cl. and alterations in its anthers parasited by Ustilago violacea (Pers.) Rouss. (Ustilaginales)

2014 ◽  
Vol 50 (1-2) ◽  
pp. 29-32 ◽  
Author(s):  
Jean-Claude Audran ◽  
Mekinto Batcho
Keyword(s):  
Early Stage ◽  
Pollen Grains ◽  
Silene Dioica ◽  
Electron Microscopic ◽  
Ustilago Violacea ◽  
Sporogenous Tissue ◽  
Microscopic Techniques

Healthy and infected anthers are comparatively studied with optical and electron microscopic techniques. The fungus stops the stamen histogenesis at an early stage and destroys specifically the sporogenous tissue.

Mouthpart and foregut ontogeny in phyllosoma larvae of the spiny lobster Jasus edwardsii (Decapoda: Palinuridae)

2001 ◽  
Vol 52 (8) ◽  
pp. 1375 ◽  
Author(s):  
Danielle J. Johnston ◽  
Arthur Ritar
Keyword(s):  
Larval Development ◽  
Early Stage ◽  
Structural Characteristics ◽  
Spiny Lobster ◽  
Filter Press ◽  
Primary Role ◽  
Formulated Diets ◽  
Jasus Edwardsii ◽  
Phyllosoma Larvae

Mouthpart and foregut structure indicates that Jasus edwardsii phyllosomas ingest soft fleshy foods such as gelatinous zooplankton. Mouthpart morphology changes little during larval development, indicating that ingestive capabilities and external mastication are well developed from an early age. However, the density and complexity of setation and robustness of individual mouthparts increases with age, suggesting a greater capacity to ingest larger prey during development. The foregut consists of a single chamber with a number of well-developed grooves, ridges, and setae but lacking a gastric mill. The primary role of the foregut is mixing, sorting, and filtering particles, preground by the mouthparts. Phyllosomas have been divided into early (stage I–III), mid (IV–V), and late (VI–X) stages based on the development of the filter press and main brushes. Increasing robustness of setation and complexity of the foregut suggest that the texture of prey becomes more muscular (fibrous) with larval development. The results presented here suggest that early-stage phyllosoma would benefit from a diet comprising soft gelatinous items, whereas late-stage phyllosomas are better prepared to deal with larger, fleshy prey. The changes in structural characteristics with age should also serve as a guide in the development of formulated diets.

QUANTITATIVE MUELLER MATRIX POLARIMETRY TECHNIQUES FOR BIOLOGICAL TISSUES

2012 ◽  
Vol 05 (03) ◽  
pp. 1250017 ◽  
Author(s):  
HONGHUI HE ◽  
NAN ZENG ◽  
DONGZHI LI ◽  
RAN LIAO ◽  
HUI MA
Keyword(s):  
Early Stage ◽  
Structural Characteristics ◽  
Potential Method ◽  
Biological Tissues ◽  
Anisotropic Scattering ◽  
Mueller Matrix ◽  
Matrix Transformation ◽  
Scattering Media ◽  
Tissue Samples ◽  
The Media

We propose and conduct both the rotating linear polarization imaging (RLPI) and Mueller matrix transformation (MMT) measurements of different biological tissue samples, and testify the capability of the Mueller matrix polarimetry for the anisotropic scattering media. The independent parameters extracted from the RLPI and MMT techniques are compared and analyzed. The tissue experimental results show that the parameters are closely related to the structural characteristics of the turbid scattering media, including the sizes of the scatterers, the angular distribution and order of alignment of the fibers. The results and conclusions in this paper may provide a potential method for the detection of precancerous and early stage cancerous tissues. Also, such studies represent the Mueller matrix transformation procedure which results in a set of parameters linking up the Mueller matrix elements to the structural and optical properties of the media.

Histological changes during progression of adenoid cystic carcinoma

1992 ◽  
Vol 106 (11) ◽  
pp. 1016-1020 ◽  
Author(s):  
Yuzo Yamamoto ◽  
Tetsuro Saka ◽  
Kazuo Makimoto ◽  
Hiroaki Takahashi
Keyword(s):  
Adenoid Cystic Carcinoma ◽  
Poor Prognosis ◽  
Early Stage ◽  
Primary Tumour ◽  
Reverse Direction ◽  
Histological Changes ◽  
Histological Features ◽  
Metastatic Lesions ◽  
Adenoid Cystic ◽  
Histological Transformation

AbstractEight cases of adenoid cystic carcinoma were reviewed to determine whether and how the histological features of the tumour vary with the progress of the disease. The tumours were classified by their histological patterns as tubular, cribriform, trabecular or solid. The relative amount of each pattern seen in routine light microscopic sections was calculated histomorphometrically and compared in the primary tumour and recurrent and/or metastatic lesions in the same case. In the early stage, the tubular pattern predominated. Later, the highest percentage shifted to the cribriform, then to the trabecular and finally, in the late stage, to the solid pattern. There was no reverse direction of histological transformation from the solid to the tubular pattern. These results may help to explain previous reports that the tubular pattern usually represents a favourable prognosis, the solid pattern a poor prognosis and the cribriform pattern an intermediate prognosis.

scholarly journals Damage identification using modal strains identified from operational fiber-optic Bragg grating data

2017 ◽  
Vol 17 (6) ◽  
pp. 1441-1459 ◽  
Author(s):  
Dimitrios Anastasopoulos ◽  
Maure De Smedt ◽  
Lucie Vandewalle ◽  
Guido De Roeck ◽  
Edwin P.B. Reynders
Keyword(s):  
Fiber Optic ◽  
Early Stage ◽  
Structural Characteristics ◽  
Mode Shapes ◽  
Dynamic Strain ◽  
Bragg Grating ◽  
Local Damage ◽  
Strain Mode ◽  
Displacement Mode ◽  
Strain Mode Shapes

Vibration-based structural health monitoring of civil structures relies on the repeated identification of dynamic structural characteristics of the structure from output-only vibration data. Natural frequencies and displacement mode shapes are the most commonly employed dynamic characteristics; yet their sensitivity to local damage of moderate severity is rather low with respect to their sensitivity to other factors such as temperature, necessitating data normalization. Strain mode shapes offer a higher sensitivity to local damage, but their accurate identification in a dense grid is challenging given the very small dynamic strain levels that are encountered under ambient excitation. In this article, a method is presented for tackling this challenge. It consists of three stages. First, fiber-optic Bragg grating strain sensors are attached to the structure and interrogated with a tunable laser performing a wavelength sweep. In this way, the measured strain amplitudes have the required accuracy but synchronization errors are introduced between the different Bragg sensors. Second, a modal analysis is performed on the dynamic strain data using an accurate parametric system identification technique. This is followed by a synchronization step which compensates for the delays introduced by the wavelength sweep. Finally, the synchronized strain mode shapes are employed as damage-sensitive features, either directly or via a newly proposed quantity, the top-to-bottom strain ratio. The method is validated by progressive damage testing of a complex, prestressed concrete “roof” beam, reinforced with steel fibers. It is observed that the proposed method can identify both the presence and the location of the damage in a relatively early stage.

scholarly journals INDIVIDUAL TREE CROWN DELINEATION USING MULTI-WAVELENGTH TITAN LIDAR DATA

2017 ◽  
Vol XLII-3/W3 ◽  
pp. 143-148 ◽  
Author(s):  
F. Naveed ◽  
B. Hu
Keyword(s):  
Structural Information ◽  
Early Stage ◽  
Structural Characteristics ◽  
Emerald Ash Borer ◽  
Region Growing ◽  
Accurate Method ◽  
Lidar Data ◽  
Individual Tree ◽  
Tree Crowns ◽  
Crown Delineation

The inability to detect the Emerald Ash Borer (EAB) at an early stage has led to the enumerable loss of different species of ash trees. Due to the increasing risk being posed by the EAB, a robust and accurate method is needed for identifying Individual Tree Crowns (ITCs) that are at a risk of being infected or are already diseased. This paper attempts to outline an ITC delineation method that employs airborne multi-spectral Light Detection and Ranging (LiDAR) to accurately delineate tree crowns. The raw LiDAR data were initially pre-processed to generate the Digital Surface Models (DSM) and Digital Elevation Models (DEM) using an iterative progressive TIN (Triangulated Irregular Network) densification method. The DSM and DEM were consequently used for Canopy Height Model (CHM) generation, from which the structural information pertaining to the size and shape of the tree crowns was obtained. The structural information along with the spectral information was used to segment ITCs using a region growing algorithm. The availability of the multi-spectral LiDAR data allows for delineation of crowns that have otherwise homogenous structural characteristics and hence cannot be isolated from the CHM alone. This study exploits the spectral data to derive initial approximations of individual tree tops and consequently grow those regions based on the spectral constraints of the individual trees.

scholarly journals SlTDP1 Is Required To Specify Tapetum Identity And For The Regulation Of Redox Homeostasis In Tomato Anthers

2021 ◽  
Author(s):  
Blanca Salazar-Sarasua ◽  
María Jesús López-Martín ◽  
Edelín Roque ◽  
Rim Hamza ◽  
Luis Antonio Cañas ◽  
...  
Keyword(s):  
Early Stage ◽  
Redox Homeostasis ◽  
Loss Of Function ◽  
Ros Scavenging ◽  
Tomato Plants ◽  
Sporogenous Tissue ◽  
Ros Homeostasis ◽  
Ros Accumulation ◽  
Scavenging Enzymes ◽  
Mother Cells

ABSTRACTThe tapetum is a specialized layer of cells within the anther adjacent to the sporogenic tissue. During its short life, it provides nutrients, molecules and materials to the pollen mother cells and microsporocytes being essential during callose degradation and pollen wall formation. However, the acquisition of tapetal cell identity in tomato plants is a process still poorly understood. We report here the identification and characterization of SlTPD1 (Solanum lycopersicum TPD1), a gene specifically required for pollen development in tomato plants. Gene editing was used to generate loss-of-function Sltpd1 mutants that showed absence of tapetal tissue. In these plants, sporogenous cells developed but failed to complete meiosis resulting in complete male sterility. Transcriptomic analysis conducted in wild-type and mutant anthers at an early stage revealed the down regulation of a set of genes related to redox homeostasis. Indeed, Sltpd1 anthers showed a reduction of reactive oxygen species (ROS) accumulation at early stages and altered activity of ROS scavenging enzymes. The obtained results highlight the importance of ROS homeostasis in the interaction between the tapetum and the sporogenous tissue in tomato plants.One sentence summaryThe small protein SlTPD1 is required for tapetum formation in tomato, highlighting the role of this tissue in the regulation of redox homeostasis during male gametogenesis.

Problem-solving by total productive maintenance swift teams: communication network structure, media choice and team effectiveness

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jorge Colazo
Keyword(s):  
Problem Solving ◽  
Communication Networks ◽  
Early Stage ◽  
Structural Characteristics ◽  
Media Choice ◽  
Male Participant ◽  
Success Rates ◽  
Communication Structure ◽  
Content Type ◽  
Problem Solving Process

PurposeThis study aims to look at the performance, communication structure and media choice for swift teams (STs) formed with the purpose of recovering from operational emergencies in manufacturing. The problem-solving process associated with these ad hoc teams include an early stage, where the main goal is to restore the process to working conditions, and a later stage, longer in duration, where the root cause of the problem is found and eliminated.Design/methodology/approachBased on field data from an industrial manufacturing operation, the authors test hypotheses by means of regression models.FindingsIt was found that in the evolution from early to later stage, media usage shifts from highly synchronous to asynchronous and the structural characteristics of the teams' collaboration networks mutate as well. These effects are different when comparing high- vs low-performing teams.Research limitations/implicationsThe study contains data for only one company, limiting the external validity of the conclusions. The sample was predominantly male. Participant attrition and other potential covariates not included in the study can be additional limitations.Practical implicationsMore successful teams adapt their communication patterns more rapidly, going from an initially decentralized organization to a more centralized one. These changes in network patterns open a new view of ST’s success, based on network characteristics rather than on aggregate measures. The conclusions yield insights for interventions that may increase the success rates of these teams and reduce production line downtime.Originality/valueThe two stages in the operational emergency problem-solving process have to the authors’ knowledge not been addressed simultaneously in previous research, which is attempted in this paper as its main theoretical contribution. Moreover, previous studies dealing with ST’s success have only looked at aggregated measures impacting effectiveness and never to how their communication networks evolve along the path to problem resolution. The network view of the evolution of the ST from a relatively disorganized impromptu agglomeration of individuals to an effective problem-solving organization is to the authors’ knowledge first presented.

scholarly journals Animal models of ovariectomy in rats demonstrate characteristics similar to early stage osteoarthritis

2021 ◽  
Author(s):  
Natália Aparecida Casonato ◽  
Camila Marques de Araújo ◽  
Mariane Santos Trevisan ◽  
Cristina Arrais Lima ◽  
Fernando Augusto Vasilceac
Keyword(s):  
Animal Models ◽  
Knee Joint ◽  
Wistar Rats ◽  
Early Stage ◽  
Experimental Period ◽  
Histological Evaluation ◽  
Control Group ◽  
Intermediate Region ◽  
Histological Changes ◽  
Deep Region

Abstract Purpose The aim of our study is to analyze the model of ovariectomy (OVX) in rats reproduced histological changes of osteoarthritis (OA). Methods For the development of the research, 12 Wistar rats were used, divided into 2 equal groups: Control Group - C (n = 6) and Osteoarthritis Group - OA (n = 6). After the 6-month experimental period, all rats were sacrificed and, subsequently, the entire knee joint complex was removed without disarticulation. For the histological evaluation of the tissue, the recommendations of the International Society for Research in OA (OARSI) were used. For data processing, each evaluation was statistically treated in both groups, comparing data from group C with the group OA. Results: Through the histological evaluation of OARSI, the evolution of OA in various tissues of the joint was evaluated. Although the OA group showed noticeable differences from group C, they were not as significant. Thus, only statistically significant favors were presented in the loss of the cartilaginous matrix (OA and C, p = 0.51), considering that the changes in the loss of ECM occurred only at the depth of 0% (superficial region), but at the depth of 50% (intermediate region) and 100% depth (deep region) did not exist. Conclusion Our study demonstrated that the OVX model is a good model to discuss OA, showing histological changes similar to those found in OA, the model demonstrated to have a progressive and slow characteristic since after the OARSI evaluations, prominent evidence was found in the initial manifestations of OA.

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