Normal Development
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2022 ◽  
Vol 8 (1) ◽  
pp. 81-85
Author(s):  
B. Asadova

Stress factors limit the development of living organisms, especially plants, and reduce their productivity. In this regard, the study of the effects of stress factors on plants and the discovery of adaptation mechanisms play an important role in the regulation of stress in the cell. From a biological point of view, stress is considered to be any change in the external environment that impairs the normal development of the plant or changes it in a negative direction. Stresses cause changes in the physiological activity of plants, weaken the process of biosynthesis in the cell, disrupt normal life and ultimately can cause plant death.


2022 ◽  
Author(s):  
Marius Lange ◽  
Volker Bergen ◽  
Michal Klein ◽  
Manu Setty ◽  
Bernhard Reuter ◽  
...  

AbstractComputational trajectory inference enables the reconstruction of cell state dynamics from single-cell RNA sequencing experiments. However, trajectory inference requires that the direction of a biological process is known, largely limiting its application to differentiating systems in normal development. Here, we present CellRank (https://cellrank.org) for single-cell fate mapping in diverse scenarios, including regeneration, reprogramming and disease, for which direction is unknown. Our approach combines the robustness of trajectory inference with directional information from RNA velocity, taking into account the gradual and stochastic nature of cellular fate decisions, as well as uncertainty in velocity vectors. On pancreas development data, CellRank automatically detects initial, intermediate and terminal populations, predicts fate potentials and visualizes continuous gene expression trends along individual lineages. Applied to lineage-traced cellular reprogramming data, predicted fate probabilities correctly recover reprogramming outcomes. CellRank also predicts a new dedifferentiation trajectory during postinjury lung regeneration, including previously unknown intermediate cell states, which we confirm experimentally.


eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Corine M van der Weele ◽  
William R Jeffery

Dark caves lacking primary productivity can expose subterranean animals to hypoxia. We used the surface-dwelling (surface fish) and cave-dwelling (cavefish) morphs of Astyanax mexicanus as a model for understanding the mechanisms of hypoxia tolerance in the cave environment. Primitive hematopoiesis, which is restricted to the posterior lateral mesoderm in other teleosts, also occurs in the anterior lateral mesoderm in Astyanax, potentially pre-adapting surface fish for hypoxic cave colonization. Cavefish have enlarged both hematopoietic domains and develop more erythrocytes than surface fish, which are required for normal development in both morphs. Laboratory induced hypoxia suppresses growth in surface fish but not in cavefish. Both morphs respond to hypoxia by overexpressing hypoxia-inducible factor 1 (hif1) pathway genes, and some hif1 genes are constitutively upregulated in normoxic cavefish to similar levels as in hypoxic surface fish. We conclude that cavefish cope with hypoxia by increasing erythrocyte development and constitutive hif1 gene overexpression.


2022 ◽  
Vol 96 ◽  
Author(s):  
Alice Namias ◽  
Lynda F. Delph ◽  
Curtis M. Lively

Abstract Natural selection should favour parasite genotypes that manipulate hosts in ways that enhance parasite fitness. However, it is also possible that the effects of infection are not adaptive. Here we experimentally examined the phenotypic effects of infection in a snail–trematode system. These trematodes (Atriophallophorus winterbourni) produce larval cysts within the snail's shell (Potamopyrgus antipodarum); hence the internal shell volume determines the total number of parasite cysts produced. Infected snails in the field tend to be larger than uninfected snails, suggesting the hypothesis that parasites manipulate host growth so as to increase the space available for trematode reproduction. To test the hypothesis, we exposed juvenile snails to trematode eggs. Snails were then left to grow for about one year in 800-l outdoor mesocosms. We found that uninfected males were smaller than uninfected females (sexual dimorphism). We also found that infection did not affect the shell dimensions of males. However, infected females were smaller than uninfected females. Hence, infection stunts the growth of females, and (contrary to the hypothesis) it results in a smaller internal volume for larval cysts. Finally, infected females resembled males in size and shape, suggesting the possibility that parasitic castration prevents the normal development of females. These results thus indicate that the parasite is not manipulating the growth of infected hosts so as to increase the number of larval cysts, although alternative adaptive explanations are possible.


2021 ◽  
Vol 12 (1) ◽  
pp. 62-69
Author(s):  
Nusrat Sultana ◽  
Faria Afsana ◽  
Nazma Akhtar ◽  
Yasmin Aktar ◽  
Mohammad Feroz Amin ◽  
...  

Precocious puberty is commonly defined as puberty that starts before age 8 years in girls and 9 years in boys. The causes of it may range from a variant of normal development to various pathologic conditions. The etiology of precocious puberty is classified by the underlying pathogenesis into gonadotropin dependent central precocious puberty and peripheral precocious puberty which is independent of gonadotropin but due to different other causes. Variants of precocious puberty include premature thelarche, premature puberche and isolated premature menarche which imply onset of isolated changes without any other signs of sexual development. Precocious puberty might have an impact on final stature owing to premature epiphyseal fusion and also it has got influence on psychosocial wellbeing. Evaluation includes a detailed history, physical examination, biochemical testing and imaging directed towards suspected etiology. Gonadotropin releasing hormone (GnRH) analogues are effective for treatment of central precocious puberty. Treatment of peripheral precocious puberty should be based on the specific cause. Pubertal variants are usually non-progressive and need no treatment but should be monitored carefully. BIRDEM Med J 2022; 12(1): 62-69


2021 ◽  
Vol LXXXII (5) ◽  
pp. 387-398
Author(s):  
Hubert Iwanicki ◽  
Agnieszka Lacek

The article focuses on the issues related to the education system of students with special educational needs. At the beginning, the concept of "parental attitude" was analysed and the main typology of parental attitudes was discussed. Then the concept and the essence of special educational needs and integrate education, inclusive education were explained along with the relationship between them. The organization of integrate education was also characterized. The main part of the publication is devoted to the presentation of the results of research carried out in order to learn about and present the attitudes of parents of children with normal development towards the education system of pupils with special educational needs. The research was carried out using the diagnostic survey method and survey technique. These studies have shown that parents of children with normal development mostly have a positive attitude towards the education system of students with special educational needs. Only some of them, who are in the minority, present a strongly or rather negative attitude. Parents of children with normal development demonstrate a great knowledge about the integrate education system. There is no doubt that the entire modern education system is currently struggling with criticism not only from parents and educators, but also from the students themselves. An important activity that should take place in every educational institution is, above all, the promotion of the idea of integration. Both the integrate and inclusive education system is the future of education in Poland. That is why it is so important and necessary to undertake educational activities that increase knowledge and social awareness in this area. Thus, the creation of integrated classes becomes an opportunity for children with special educational needs because functioning in such a class enables proper social development with peers with normal development.


Author(s):  
David A. Leopold ◽  
Bruno B. Averbeck

We are curious by nature, particularly when young. Evolution has endowed our brain with an inbuilt obligation to educate itself. In this perspectives article, we posit that self-tuition is an evolved principle of vertebrate brain design that is reflected in its basic architecture and critical for its normal development. Self-tuition involves coordination between functionally distinct components of the brain, with one set of areas motivating exploration that leads to the experiences that train another set. We review key hypothalamic and telencephalic structures involved in this interplay, including their anatomical connections and placement within the segmental architecture of conserved forebrain circuits. We discuss the nature of educative behaviours motivated by the hypothalamus, innate stimulus biases, the relationship to survival in early life, and mechanisms by which telencephalic areas gradually accumulate knowledge. We argue that this aspect of brain function is of paramount importance for systems neuroscience, as it confers neural specialization and allows animals to attain far more sophisticated behaviours than would be possible through genetic mechanisms alone. Self-tuition is of particular importance in humans and other primates, whose large brains and complex social cognition rely critically on experience-based learning during a protracted childhood period. This article is part of the theme issue ‘Systems neuroscience through the lens of evolutionary theory’.


2021 ◽  
Vol 8 ◽  
Author(s):  
Guoyong Li ◽  
Tao Cheng ◽  
Xuefeng Yu

Osteoarthritis (OA) is a progressive degenerative disease characterized by cartilage degradation, synovial inflammation, subchondral sclerosis and osteophyte formation. It has a multifactorial etiology with potential contributions from heredity, endocrine function, abnormal mechanical load and nutrition. Of particular considerations are trace element status. Several trace elements, such as boron and magnesium are essential for normal development of the bone and joint in human. While cadmium correlates with the severity of OA. The present review focuses on the roles of trace elements (boron, cadmium, copper, iron, magnesium, manganese, selenium, zinc) in OA and explores the mechanisms by which they act.


2021 ◽  
Vol 23 ◽  
Author(s):  
Zhengyu Zhang ◽  
Ying Peng ◽  
Jiang Zheng

: Reactive metabolites (RMs) are products generated from the metabolism of endogenous and exogenous substances. RMs are characterized as electrophilic species chemically reactive to nucleophiles. Those nucleophilic species may be nitrogen-containing bio-molecules, including macro-biomolecules, such as protein and DNA, and small biomolecules, i.e., amino acids (AAs) and biogenic amines (BAs). AAs and BAs are essential endogenous nitrogen-containing compounds required for normal development, metabolism, and physiological functions in organisms, through participating in the intracellular replication, transcription, translation, division and proliferation, DNA and protein synthesis, regulation of apoptosis, and intercellular communication activities. These biological amines containing an active lone pair of electrons on the electronegative nitrogen atom would be the proper N-nucleophiles to be attacked by the abovementioned RMs. This review covers an overview of adductions of AAs and BAs with varieties of RMs. These RMs are formed from metabolic activation of furans, naphthalene, benzene, and products of lipid peroxidation. This article is designed to provide readers with a better understanding of biochemical mechanisms of toxic action.


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