scholarly journals Dual role for Hedgehog in the regulation of the proneural gene atonal during ommatidia development

Development ◽  
1999 ◽  
Vol 126 (11) ◽  
pp. 2345-2353 ◽  
Author(s):  
M. Dominguez

The differentiation of cells in the Drosophila eye is precisely coordinated in time and space. Each ommatidium is founded by a photoreceptor (R)8 cell and these founder cells are added in consecutive rows. Within a row, the nascent R8 cells appear in precise locations that lie out of register with the R8 cells in the previous row. The bHLH protein Atonal determines the development of the R8 cells. The expression of atonal is induced shortly before the selection of a new row of R8 cells and is initially detected in a stripe. Subsequently atonal expression resolves into regularly spaced clusters (proneural clusters) that prefigure the positions of the future R8 cells. The serial induction of atonal expression, and hence the increase in the number of rows of R8 cells, requires Hedgehog function. Here it is shown that, in addition to this role, Hedgehog signalling is also required to repress atonal expression between the nascent proneural clusters. This repression has not been previously described and appears to be critical for the positioning of Atonal proneural clusters and, therefore, the R8 cells. The two temporal responses to Hedgehog are due to direct stimulation of the responding cells by Hedgehog itself.

Neurosurgery ◽  
1986 ◽  
Vol 18 (1) ◽  
pp. 59-66 ◽  
Author(s):  
B. A. Meyerson ◽  
S. Håkanson

Abstract Lesions of the peripheral part of the trigeminal nerve may cause trigeminal neuropathy associated with severe pain. Such pain usually does not respond to carbamazepine and analgesics, and it is continuous and lacks the characteristic paroxysmal character of tic douloureux. These patients often present with complex changes of facial sensibility in the form of dysesthesia, hyperalgesia, and allodynia. The pain sometimes responds favorably to transcutaneous nerve stimulation, but direct stimulation of the trigeminal ganglion and rootlets via an implanted electrode provides a greater likelihood of pain relief. Fourteen patients diagnosed as having painful trigeminal neuropathy received implants of a gasserian ganglion-stimulating electrode. The mean follow-up period is 4 years (range, 1 to 7 years). Eleven of the patients have retained the pain-relieving effect, and 1 had pain disappear without further stimulation. Eight of the patients estimated their pain relief to be complete or very good. There were no serious complications, but in several of the patients the electrode had to be exchanged because the insulation of the lead wires broke. For the selection of patients for permanent electrode implantation, a method has been developed for trial stimulation via a percutaneous electrode introduced into the trigeminal cistern. Temporary trial stimulation can be performed for several days. It is concluded that stimulation of the trigeminal ganglion and rootlets with the aid of an implanted electrode may effectively relieve certain forms of trigeminal pain that are otherwise extremely difficult to manage.


EMBO Reports ◽  
2008 ◽  
Vol 9 (11) ◽  
pp. 1128-1133 ◽  
Author(s):  
Janghoo Lim ◽  
Hamed Jafar‐Nejad ◽  
Ya‐Chieh Hsu ◽  
Kwang‐Wook Choi

Development ◽  
2000 ◽  
Vol 127 (8) ◽  
pp. 1681-1689 ◽  
Author(s):  
N.M. White ◽  
A.P. Jarman

During Drosophila eye development, the proneural gene atonal specifies founding R8 photoreceptors of individual ommatidia, evenly spaced relative to one another in a pattern that prefigures ommatidial organisation in the mature compound eye. Beyond providing neural competence, however, it has remained unclear to what extent atonal controls specific R8 properties. We show here that reduced Atonal function gives rise to R8 photoreceptors that are functionally compromised: both recruitment and axon pathfinding defects are evident. Conversely, prolonged Atonal expression in R8 photoreceptors induces defects in inductive recruitment as a consequence of hyperactive EGFR signalling. Surprisingly, such prolonged expression also results in R8 pattern formation defects in a process associated with both Hedgehog and Receptor Tyrosine Kinase signalling. Our results strongly suggest that Atonal regulates signalling and other properties of R8 precursors.


Author(s):  
M. Kusiy

Introduction.  During the training of emergency specialists, the development of a clear, structured thinking is important.  And the mathematical disciplines themselves are aimed at activating the intellectual activity of cadets and students, the ability to think logically, consistently, and reasonably.  However, cadets and students consider mathematics to be a complex, inaccessible and not very necessary science.  Therefore, there is a need for continuous, continuous development of methods, technologies of forms of training that would increase interest, accessibility to mathematical disciplines and at the same time, were aimed at improving the quality of training of future rescuers. Purpose.  Identify the main stages of teaching higher mathematics for future civil defense specialists and substantiate their peculiarities. Methods.  The article used methods of scientific knowledge (general), methods used in the empirical and theoretical levels of research (transition from abstract to specific).  Results.  The basic stages of teaching higher mathematics for future specialists of civil defense are determined: motivation, research, assimilation, application.  The proposed stages are analyzed in detail.  The regularities that contribute to the increase of motivation (selection of educational material, system approach, creative approach, a variety of forms and methods of teaching, taking into account the specifics of the future profession, the use of innovative teaching technologies) are highlighted.  There are three phases of knowledge (curiosity, curiosity, theoretical knowledge).  It is determined that for the acquisition of knowledge it is possible to use the information - search type of classes with its microstructure.  Planning the microstructure of occupations in the first place should put the level of cognitive activity, awareness and independence in the performance of educational tasks.  It is noted that the process of assimilation is the process of internalization of knowledge, putting it into the inner plan of man, and the application is to extraorise knowledge, make it to the outline of human activity.  It was investigated that the stage of application of knowledge is divided into two parts (the first is the application of knowledge, skills in standard terms, the second - the transfer of knowledge, skills, skills in new, changed conditions).  Examples of applied tasks that can be solved in higher mathematics classes are given.  It is substantiated that only in combination of all stages is formed the need for knowledge acquisition and their application. Conclusion.  Stages of teaching higher mathematics - a cyclical process that requires constant improvement, hard work of the teacher.  Stages of motivation and application combine the same laws (selection of educational material, creative approach, taking into account the specifics of the future profession, the use of innovative teaching technologies).  And only in a logical, thought-out combination of these stages can one form the future need for civil protection specialists to expand the knowledge and apply it to practical application.


2018 ◽  
Author(s):  
F.B. Musaev ◽  
N.S. Priyatkin ◽  
M.V. Arkhipov ◽  
P.A. Shchukina ◽  
A.F. Bukharov ◽  
...  

Приведено описание разработанной авторами методики цифровой компьютерной морфометрии семян овощных культур на основе системы анализа изображений, состоящей из планшетного сканера и программного обеспечения для автоматических измерений. В основу метода положено представление о разнокачественности семян, обусловленной генетической неоднородностью самих семенных растений, используемых в промышленном семеноводстве. Физические свойства семян (их форма и линейные размеры) – основные параметры при определении их качества. Цифровые изображения семян получены при помощи планшетного сканера HP Sсanjet 200 на базе Агрофизического НИИ с использованием серийного программного обеспечения «Argus-BIO», производства ООО «АргусСофт» (г. Санкт-Петербург). Метод состоит из подбора контрастной подложки (фона) для сканирования семян с минимальными теневыми эффектами, калибровку программного обеспечения для привязки к истинным размерным величинам, подбор параметров измерений и автоматическое распознавание цифровых сканированных изображений семян. Представлены экспериментальные данные по морфометрии экологически разнокачественных семян фасоли овощной, матрикально разнокачественных семян укропа, пастернака и лука Кристофа. Семена укропа и пастернака, собранные из разных порядков ветвления семенного растения, значительно различались по величине линейных параметров. Наиболее показательный линейный параметр семян – площадь проекции. Предложенная авторами методика цифровой морфометрии, уже использована на практике и в перспективе может быть задействована в исследованиях экологической и матрикальной разнокачественности семян овощных культур. Так, она прошла апробацию на разнокачественных семенах пяти сортов фасоли овощной (Настена, Магура, Миробела, Морена, Бажена) полученных в пяти контрастных эколого-географических условиях среды (Москва, Белгород, Ставрополь, Омск, Горки) в 2011–2012 годах. В дальнейшем методика может быть использована для улучшения качества цифровых изображений семян, изучения разнокачественности семян в том числе и для совершенствования контроля за селекционным процессом. Кроме того, она применима для изучения взаимосвязи совокупности морфометрических характеристик семян и их посевных качеств.The description of the method of digital computer morphometry of vegetable seeds developed by the authors on the basis of the image analysis system consisting of a flatbed scanner and software for automatic measurements is given. The method is based on the idea of seed quality, due to the genetic heterogeneity of the seed plants used in industrial seed production. Physical properties of seeds (their shape and linear dimensions) are the main parameters in determining their quality. Digital image of the seed obtained using the flatbed scanner, HP Sсanjet 200 on the basis of the Agrophysical research Institute with serial software “Argus-BIO”, produced by LLC “Argussoft” (Saint-Petersburg). The method consists of selection of a contrast substrate (background) for scanning seeds with minimal shadow effects, calibration of software for binding to true size values, selection of measurement parameters and automatic recognition of digital scanned images of seeds. Experimental data on the morphometry of ecologically different-quality seeds of vegetable beans, matrix seeds of dill, Pasternak and Christoph onion are presented. Seeds of dill and parsnip, collected from different orders of branching of the seed plant, significantly differed in size of linear parameters. The most revealing linear parameter seed – area projection. The method of digital morphometry proposed by the authors has already been used in practice and in the future can be used in studies of ecological and matrix heterogeneity of vegetable seeds. So, it was tested on different quality seeds of five varieties of vegetable beans (Nastena, Magura, Mirobelа, Morena, Bazhenf) obtained in five contrasting environmental and geographical conditions (Moscow, Belgorod, Stavropol, Omsk, Gorki) in 2011-2012. In the future, the technique can be used to improve the quality of digital images of seeds, study of seed diversity, including to improve the control of the breeding process. In addition, it is applicable to study the relationship of the set of morphometric characteristics of seeds and their sowing qualities.


2016 ◽  
Vol 52 ◽  
pp. 194-202
Author(s):  
S. L. Voitenko ◽  
L. V. Vishnevsky

The article shows the state of Ukrainian Whiteheaded cattle, which includes distribution of cattle, the number of animals belonging to respective bloodlines, evaluation of young animals with live weight in the process of growing and milk production of cows during the first lactation. It reflects the historic development of the breed when it was colonism whiteheaded cattle, which turned into the original breed, undergone a significant expansion in livestock and increase of productivity, decreased in the number, was as basis for creation of Ukrainian Black-and-White dairy breed and now bred only in one breeding farm. Visual estimation of animal exterior showed good development of cows and calves and their belonging to the dairy type. In the vast majority the cows of the herd have a black suit, a white head with " glasses" around the eyes, white belly, udder, lower legs and brush of the tail. The youngsters aren’t consolidated by the exterior, and among them there are animals which are not typical for Ukrainian Whiteheaded breed. The young animals have some lag in live weight behind the breed standard [12] to 7 months’ age with exceeding of this trait in certain periods quite significantly in the future. It was established that selection of heifers on live weight will be effective at the early age (1-5 months), given the coefficient of variation of live weight – 22,63-30,21% and will not have a significant influence in the future. Milk yields of first-calf heifers vary considerably depending on the origin. The milk yield of first-calf heifers in the herd was 4238,5 kg on average, the heifers belonging to Mart 171 and Ozon 417 bloodlines had the best milk performance – 4483,1 and 4254,9 kg accordingly. The most aligned milk yield during the first lactation was in the cows belonging to Ozon 417 bloodline, the limits of the trait are 4128,5-4327,4 kg with the average value by the line 4254,9 kg. In contrast, the first-calf heifers of Ryezvyi 33 bloodline with average milk yield 4048,9 kg had limits of the trait 2199,3-4736,1 kg. Even greater range in cows’ milk yield during the first lactation R= 4939 kg (limits 1687 – 6626 kg) is characterized for the herd in general, it shows, on the one hand, the possibility of qualitative improvement of cows’ productivity due to selection on the investigated trait and lack of selection in the herd on the other hand. It was established that daughters of bull Chardash belonging to Ryezvyi 33 bloodline produced 4736,1 kg of milk for 305 days of the first lactation with fat content 3,6%, whereas Zlak’s descendants of the same line were characterized by the lowest milk yield for the first completed lactation – 2199,3 kg with fat content 3,7% and the average value by the line – 4048,9 kg of milk, fat content 3,6%. Similar variability of first-calf heifers’ milk yields, depending on the origin, is typical for other bloodlines of Ukrainian Whiteheaded breed. To increase milk productivity of Ukrainian Whiteheaded cows is recommended to repeat successful combinations of parental forms, and to preserve the breed – to carry out an objective assessment of animals by a range of traits, given the efficiency of selection of heifers on live weight at early age.


Author(s):  
Janice L. Waldron ◽  
Stephanie Horsley ◽  
Kari K. Veblen

We all feel the implications of the force of social media—for good and for ill—in our lives and in our professional world. At the time of this writing, Facebook continues with its struggle to “clean up its act” as more revelations surrounding breaches of trust and hacked user data surface in the news and various countries attempt to hold Facebook to account. Despite this, social media use continues to grow exponentially, and the potential for responsible, ethical, and transparent social media to transform the ways in which we interact with and learn from each other increase with it. As we wait to see what the future holds for social media in society, we are reminded once again that it is the careful selection of pedagogical tools such as social media, as well the guided awareness of the challenges and benefits of those tools, that remains constant, even as tools may change, disappear, or fall out of fashion.


2021 ◽  
Vol 9 (3) ◽  
pp. 24
Author(s):  
Brian Heubel ◽  
Anja Nohe

The osteogenic effects of Bone Morphogenetic Proteins (BMPs) were delineated in 1965 when Urist et al. showed that BMPs could induce ectopic bone formation. In subsequent decades, the effects of BMPs on bone formation and maintenance were established. BMPs induce proliferation in osteoprogenitor cells and increase mineralization activity in osteoblasts. The role of BMPs in bone homeostasis and repair led to the approval of BMP2 by the Federal Drug Administration (FDA) for anterior lumbar interbody fusion (ALIF) to increase the bone formation in the treated area. However, the use of BMP2 for treatment of degenerative bone diseases such as osteoporosis is still uncertain as patients treated with BMP2 results in the stimulation of not only osteoblast mineralization, but also osteoclast absorption, leading to early bone graft subsidence. The increase in absorption activity is the result of direct stimulation of osteoclasts by BMP2 working synergistically with the RANK signaling pathway. The dual effect of BMPs on bone resorption and mineralization highlights the essential role of BMP-signaling in bone homeostasis, making it a putative therapeutic target for diseases like osteoporosis. Before the BMP pathway can be utilized in the treatment of osteoporosis a better understanding of how BMP-signaling regulates osteoclasts must be established.


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