scholarly journals Changes in segmentation and setation along the anterior/posterior axis of the homonomous trunk limbs of a remipede (Crustacea, Arthropoda)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2305 ◽  
Author(s):  
Viacheslav N. Ivanenko ◽  
Ekaterina A. Antonenko ◽  
Mikhail S. Gelfand ◽  
Jill Yager ◽  
Frank D. Ferrari

This study describes the segmentation and setation at different developmental stages of the homonomous trunk limbs of the remipedeSpeleonectes tulumensisYager, 1987 collected in anchialine caves of the Yucatan Peninsula. Most homonomous trunk limbs originate ventrolaterally and are composed of two protopodal segments, three exopodal segments and four endopodal segments; contralateral limb pairs are united by a sternal bar. However, the last few posterior limbs originate ventrally, are smaller sized, and have regressively fewer segments, suggesting that limb development passes through several intermediate steps beginning with a limb bud. A terminal stage of development is proposed for specimens on which the posterior somite bears a simple bilobate limb bud, and the adjacent somite bears a limb with a protopod comprised of a coxapod and basipod, and with three exopodal and four endopodal segments. On each trunk limb there are 20 serially homologous groups of setae, and the numbers of setae on different limbs usually varies. These groups of setae are arranged linearly and are identified based on the morphology of the setae and their position on the segments. The number of setae in these groups increases gradually from the anterior homonomous limb to a maximum between limbs 8–12; the number then decreases sharply on the more posterior limbs. Changes in the number of setae, which reach a maximum between trunk limbs 8–12, differ from changes in segmentation which vary only over the last few posterior trunk limbs. Following a vector analysis that identified a spatial pattern for these 20 groups of setae among the different homonomous limbs, the hypothesis was confirmed that the number of setae in any given group and any given limb is correlated with the group, with the position of the somite along the body axis, and with the number of somites present on the specimens. This is the first vector analysis used to analyze a pattern of developmental changes in serially homologs of an arthropod. Development of remipede limbs are compared and contrasted with similar copepod limbs. Architecture, particularly the sternal bar uniting contralateral limb pairs, proposed as homologous, and development of trunk limb segmentation of the remipede is generally similar to that of copepods, but the remipede limb differs in several ways including an additional endopodal segment, the proximal, that appears simultaneously with the protopod during development.

Development ◽  
1986 ◽  
Vol 94 (1) ◽  
pp. 267-275
Author(s):  
C. P. Cottrill ◽  
Paul T. Sharpe ◽  
Lewis Wolpert

A technique which identifies cells differing in surface character, aqueous two-phase partition using thin-layer countercurrent distribution (TLCCD), has been used to study differentiation and pattern formation in the developing chick limb bud. The TLCCD profiles of cell populations, derived from various regions of morphologically undifferentiated mesenchyme from three different stages of limb development, have been compared. At no stage, or location, has the population been found to be homogeneous. Cells from progress zones and more proximal regions could all be resolved into several populations. The populations from progress zones at three different developmental stages were qualitatively similar but differed in the proportions of cells in each. The most striking differences in cell populations were those obtained from the most proximal region of the limb, closest to the flank, which represents the developmentally most advanced region.


2005 ◽  
Vol 74 (1-2) ◽  
pp. 61-76 ◽  
Author(s):  
S. Grosjean

The morphology of tadpoles has long received too little attention in taxonomic and phylogenetic contexts, beyond the use of Orton’s general tadpole types, despite the potential of larval characters for resolving problems in systematics. A possible explanation for this neglect is the ontogenetic variation of external morphology. In order to understand the value of larval characters in taxonomy and systematics, it is necessary to determine the developmental stage at which characters reach their definitive size, form and colour before meaningful comparisons can be made within and between species. Here I use the tadpole of Rana (Sylvirana) nigrovittata as a model organism to assess ontogenetic character variation. Morphometric measurements were taken, and external oral and internal buccal characters were assessed separately for each developmental stage from 26 to 38. Coefficients of variation were calculated for each morphometric character at each stage of development to test the character’s efficiency in reflecting the morphology of the tadpole. Most morphometric characters taken from the body described the shape of the animal well and varied little among individuals, whereas those taken from the tail were less reliable and those of the oral disk were quite variable due to contraction during fixation. A developmental 'climax' for most characters was reached by specimens between stages 32-40, indicating that they are best suited for morphological intra- and interspecific comparisons.


Author(s):  
Jessica Cristina Marín-Llera ◽  
Carlos Ignacio Lorda-Diez ◽  
Juan Mario Hurle ◽  
Jesús Chimal-Monroy

At early developmental stages, limb bud mesodermal undifferentiated cells are morphologically indistinguishable. Although the identification of several mesodermal skeletal progenitor cell populations has been recognized, in advanced stages of limb development here we identified and characterized the differentiation hierarchy of two new early limb bud subpopulations of skeletal progenitors defined by the differential expression of the SCA-1 marker. Based on tissue localization of the mesenchymal stromal cell-associated markers (MSC-am) CD29, Sca-1, CD44, CD105, CD90, and CD73, we identified, by multiparametric analysis, the presence of cell subpopulations in the limb bud capable of responding to inductive signals differentially, namely, sSca+ and sSca– cells. In concordance with its gene expression profile, cell cultures of the sSca+ subpopulation showed higher osteogenic but lower chondrogenic capacity than those of sSca–. Interestingly, under high-density conditions, fibroblast-like cells in the sSca+ subpopulation were abundant. Gain-of-function employing micromass cultures and the recombinant limb assay showed that SCA-1 expression promoted tenogenic differentiation, whereas chondrogenesis is delayed. This model represents a system to determine cell differentiation and morphogenesis of different cell subpopulations in similar conditions like in vivo. Our results suggest that the limb bud is composed of a heterogeneous population of progenitors that respond differently to local differentiation inductive signals in the early stages of development, where SCA-1 expression may play a permissive role during cell fate.


2015 ◽  
Vol 71 (8) ◽  
pp. 522-526
Author(s):  
Katarzyna Czepiel-Mil ◽  
Aleksandra Łoś ◽  
Patrycja Marczewska

Entomotoxicology deals with the analysis of toxic substances contained in arthropods that feed on dead bodies. Arthropods are a source of material for investigation when a human or animal body is in an advanced state of decomposition. Various chemical air pollutants, drugs, xenobiotics and pesticides can accumulate in the bodies of insect larvae. Entomotoxicology often involves examining insect larvae that have introduced to their metabolism various kinds of pharmaceuticals taken by people when they were alive. Chemical compounds which can cause death affect the development rate of arthropods living on corpses, delay colonization of insects by several days, or affect their number. Some compounds act as attractants or repellents and thereby influence how quickly insects appear on the body. Others have a mixed effect on insect development. During the initial development stage of the insect they act as an attractant, but in subsequent stages they slow down its development or act as a repellent. The concentration of chemical compounds accumulated in the bodies of larvae is different than in human tissues. Sometimes insects are better indicators of the presence of chemical compounds than material taken from the internal organs of a dead body. Moreover, the quantity of toxins detected in arthropods differs at different developmental stages. The concentration of a xenobiotic in the body of an insect depends on its type, the stage of development of the insect, and the part of the body it was collected from. Studies have determined that the best place to collect entomotoxicological samples is the internal organs (e.g. the liver). If this is not possible, insects are collected from the head area and the muscles. Due to the low popularity of entomotoxicological testing, this type of evidence often is either not collected at all or collected improperly, preventing valuable information from being obtained. Thus there is a need to verify and standardize methods for safeguarding arthropods for the purposes of entomological toxicology


1999 ◽  
Vol 86 (3) ◽  
pp. 779-786 ◽  
Author(s):  
John J. Greer ◽  
Douglas W. Allan ◽  
Miguel Martin-Caraballo ◽  
Robert P. Lemke

In this overview, we outline what is known regarding the key developmental stages of phrenic nerve and diaphragm formation in perinatal rats. These developmental events include the following. Cervical axons emerge from the spinal cord during embryonic (E) day 11. At ∼E12.5, phrenic and brachial axons from the cervical segments merge at the brachial plexi. Subsequently, the two populations diverge as phrenic axons continue to grow ventrally toward the diaphragmatic primordium and brachial axons turn laterally to grow into the limb bud. A few pioneer axons extend ahead of the majority of the phrenic axonal population and migrate along a well-defined track toward the primordial diaphragm, which they reach by E13.5. The primordial diaphragmatic muscle arises from the pleuroperitoneal fold, a triangular protrusion of the body wall composed of the fusion of the primordial pleuroperitoneal and pleuropericardial tissues. The phrenic nerve initiates branching within the diaphragm at ∼E14, when myoblasts in the region of contact with the phrenic nerve begin to fuse and form distinct primary myotubes. As the nerve migrates through the various sectors of the diaphragm, myoblasts along the nerve’s path begin to fuse and form additional myotubes. The phrenic nerve intramuscular branching and concomitant diaphragmatic myotube formation continue to progress up until E17, at which time the mature pattern of innervation and muscle architecture are approximated. E17 is also the time of the commencement of inspiratory drive transmission to phrenic motoneurons (PMNs) and the arrival of phrenic afferents to the motoneuron pool. During the period spanning from E17 to birth (gestation period of ∼21 days), there is dramatic change in PMN morphology as the dendritic branching is rearranged into the rostrocaudal bundling characteristic of mature PMNs. This period is also a time of significant changes in PMN passive membrane properties, action-potential characteristics, and firing properties.


Author(s):  
Dwi Darwati

Reproductive  health education should be given since early childhood by using language that is adapted to the stage of development. If you procrastinate and wait until the teenager it is already too late because in the days of the digital era, as now, all the information can be easily accessed by anyone including children early age. If the early childhood misinformed about their reproductive organs it would disrupt the physical and psychological development due to the wrong behavior in caring for and maintaining reproductive organs. Qur’an as the holy book of Muslims describes the steps of reproduction and  imparting education wisely as well as how to apply such education. This kind of education must be in accordance with the conditions of children and there should not be a lie about it We can also use media and methods such as pictures, songs, tap or other visual  media which can give clearer information, so that children can clearly see parts of the body, their characteristics, and how to treat and care them. The impropriate approach in conveying this kind of knowledge will be very dangerous for children. The provision of early age reproductive organs education can prevent the occurrence of deviant behavior as well as protect children from dangerous influence in early childhood development.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fang Li ◽  
Zaichao Zheng ◽  
Hongyu Li ◽  
Rongrong Fu ◽  
Limei Xu ◽  
...  

AbstractDespite the central role of hemocytes in crustacean immunity, the process of hemocyte differentiation and maturation remains unclear. In some decapods, it has been proposed that the two main types of hemocytes, granular cells (GCs) and semigranular cells (SGCs), differentiate along separate lineages. However, our current findings challenge this model. By tracking newly produced hemocytes and transplanted cells, we demonstrate that almost all the circulating hemocytes of crayfish belong to the GC lineage. SGCs and GCs may represent hemocytes of different developmental stages rather than two types of fully differentiated cells. Hemocyte precursors produced by progenitor cells differentiate in the hematopoietic tissue (HPT) for 3 ~ 4 days. Immature hemocytes are released from HPT in the form of SGCs and take 1 ~ 3 months to mature in the circulation. GCs represent the terminal stage of development. They can survive for as long as 2 months. The changes in the expression pattern of marker genes during GC differentiation support our conclusions. Further analysis of hemocyte phagocytosis indicates the existence of functionally different subpopulations. These findings may reshape our understanding of crustacean hematopoiesis and may lead to reconsideration of the roles and relationship of circulating hemocytes.


2015 ◽  
Vol 52 (3) ◽  
pp. 229-235 ◽  
Author(s):  
E. M. Mbokane ◽  
J. Theron ◽  
W. J. Luus-Powell

Abstract This study provides information on seasonal occurrence of developmental stages of endoparasites infecting three cyprinids in the Nwanedi-Luphephe dams, Limpopo River System. Labeobarbus marequensis (Smith, 1841), Barbus trimaculatus Peters, 1852 and Barbus radiatus Peters, 1853 were investigated seasonally from January 2008 to October 2008. The following larvae of metazoan parasites were collected: Diplostomum sp. from the eyes of L. marequensis and B. trimaculatus; Ornithodiplostomum sp. from the gills of B. trimaculatus; Posthodiplostomum sp. from muscle, skin and fins of B. trimaculatus and B. radiatus; third-stage Contracaecum larvae (L3) from the mesentery fats and on the liver lobes of L. marequensis and B. trimaculatus and gryporynchid cestode larvae from the outer intestinal wall of B. radiatus. All the flukes encountered were metacercariae. Diplostomum sp. and Contracaecum sp. dominated the parasite communities. Their prevalence exhibited seasonal fluctuations with maxima in summer. Factors likely to influence fish infection such as the body size of fish and their condition factors were also briefly considered in this study.


Parasitology ◽  
1964 ◽  
Vol 54 (2) ◽  
pp. 295-312 ◽  
Author(s):  
Elon E. Byrd ◽  
William P. Maples

The naturally oviposited egg of Dasymetra conferta is fully embryonated and it hatches only after it is ingested by the snail host, Physa spp.Hatching appears to be in response to some stimulus supplied by the living snail. The stimulus causes the larva to exercise a characteristic series of body movements and to liberate a granular sustance (hatching enzyme) from the larger pair of its cephalic glands. This enzyme reacts with the vitelline fluid to create pressure within the egg capsule, and with the cementum of the operculum, so that it may be lifted away. The larva's escape from the shell, therefore, is due to a combination of pressure and body movements.The hatched larva has a membranous body wall, supporting six epidermal plates, an apical papilla, two penetration glands and a central matrix (the presumptive brood mass).It lives for about an hour within the snail and during this time there is a reorganization of the central matrix which terminates in the formation of an 8-nucleated syncytial brood mass.The miracidial ‘case’, consisting of the body wall and the epidermal plates, ultimately ruptures to liberate the brood mass. Once the brood mass is free it penetrates through the gut wall in an incredibly short time.


2021 ◽  
pp. 8-14
Author(s):  
Светлана Тарасовна Быкова ◽  
Тамара Григорьевна Калинина ◽  
Ирина Макаровна Московская

Полноценное, сбалансированное питание - основной фактор в формировании здоровья детей, когда в организме наиболее интенсивно протекают процессы роста и развития, формируются и созревают многие органы и системы, совершенствуются их функции. В статье приведены основные направления исследований зарубежных и отечественных ученых по лечению генетических заболеваний, таких как фенилкетонурия. Одним из приоритетных направлений в области здорового питания населения России в соответствии со Стратегией научно-технологического развития РФ до 2030 г. является развитие производства пищевых продуктов, обогащенных незаменимыми ингредиентами, специализированных продуктов детского питания, продуктов функционального назначения, диетических пищевых продуктов и биологически активных добавок. По данным ВОЗ от структуры питания на 70 % зависят здоровье и физическое развитие детей и подростков. Фенилкетонурия (ФКУ) - наследственное заболевание, вызывающее нарушение метаболизма аминокислоты фенилаланина у ребенка, одно из первых, рекомендованных ВОЗ для ранней диагностики у новорожденных. Отсутствие лечения вызывают серьезное поражение центральной нервной системы, отставание в умственном и физическом развитии. Особенностью современного этапа развития диетотерапии для детей, страдающих различными заболеваниями, в том числе наследственными, является разработка качественных функциональных продуктов питания, способствующих сохранению и улучшению здоровья ребенка за счет регулирующего и нормализующего воздействия на организм с учетом его физиологического состояния и возраста. Данные продукты можно широко использовать в практике лечебного питания не только в составе гипофенилаланиновой диеты, но и при любых заболеваниях, требующих ее соблюдения. В настоящее время единственным методом лечения ФКУ является диетотерапия, организованная с первых дней жизни с использованием специализированных смесей без фенилаланина. Из питания исключаются высокобелковые продукты растительного и животного происхождения. Целью лечебного воздействия диеты на ребенка является поддержка концентрации фенилаланина (ФА) в крови в пределах 2-12 мг на 100 мл в зависимости от возраста ребенка. Full-fledged balanced nutrition is the main factor in the formation of children's health, when the processes of growth and development are most intense in the body, many organs and systems are formed and mature, and their functions are improved. The article presents the main research areas of foreign and domestic scientists on the treatment of genetic diseases, such as phenylketonuria. One of the priority areas in the field of healthy nutrition of the Russian population in accordance with the Strategy for Scientific and Technological Development of the Russian Federation until 2030 is the development of the production of food products enriched with essential ingredients, specialized children's food products, functional products, dietary food products and biologically active additives. According to WHO, the health and physical development of children and adolescents depends on the nutritional structure by 70%. Phenylketonuria (PKN) - an inherited disease that causes impaired metabolism of the amino acid phenylalanine in a child - is one of the first recommended by WHO for early diagnosis in newborns. Lack of treatment causes serious damage to the central nervous system, a lag in mental and physical development. A feature of the modern stage of development of dietary therapy for children suffering from various diseases, including hereditary ones, is the development of quality functional food products that contribute to the preservation and improvement of the health of the child, due to the regulatory and normalizing effect on the body, taking into account its physiological state and age. These products can be widely used in the practice of therapeutic nutrition not only in the sastava of the hypophenylalanine diet, but also for any diseases requiring its observance. Currently, the only method of treating PKN is diet therapy, organized from the first days of life using specialized mixtures without phenylalanine. High-protein products of vegetable and animal origin are excluded from nutrition. The goal of the therapeutic effect of the diet on the child is to maintain the concentration of phenylalanine (FA) in the blood in the range of 2-12 mg per 100 ml, depending on the age of the child.


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