scholarly journals Pattern of sucker development in cuttlefishes

2020 ◽  
Author(s):  
Ryosuke Kimbara ◽  
Mayuko Nakamura ◽  
Kohei Oguchi ◽  
Hisanori Kohtsuka ◽  
Toru Miura
Keyword(s):  
Ecological Niche ◽  
Developmental Process ◽  
Morphological Characteristics ◽  
Postembryonic Development ◽  
Life History Strategies ◽  
Epithelial Tissue ◽  
Ridge Structure ◽  
Oral Side ◽  
Sepia Esculenta ◽  
Morphological Novelties

Abstract Background : Morphological novelties have been acquired through evolutionary processes and related to the adaptation of new life-history strategies with new functions of the bodyparts. Cephalopod molluscs such as octopuses, squids and cuttlefishes possess unique morphological characteristics. Among those novel morphologies, in particular, suckers arranged along the oral side of each arm possess multiple functions, such as capturing prey and locomotion, so that the sucker morphology is diversified among species, depending on their ecological niche. However, the detailed developmental process of sucker formation has remained unclear, although it is known that new suckers are formed or added during both embryonic and postembryonic development. In the present study, therefore, focusing on two cuttlefish species, Sepia esculenta and S. lycidas , in which the sucker morphology is relatively simple, morphological and histological observations were carried out during embryonic and postembryonic development to elucidate the developmental process of sucker formation and to compare them among other cephalopod species. Results : The observations in both species clearly showed that the newly formed suckers were added on the oral side of the most distal tip of each arm during embryonic and postembryonic development. On the oral side of the arm tip, the epithelial tissue became swollen to form a ridge along the proximal-distal axis (sucker field ridge). Next to the sucker field ridge, there were small dome-shaped bulges that are presumed to be the sucker buds. Toward the proximal direction, the buds became functional suckers, in which the inner tissues differentiated to form the complex sucker structures. During postembryonic development, on both sides of the sucker field ridge, epithelial tissues extended to form a sheath, covering the ridge for protection of undifferentiated suckers. Conclusions : The developmental process of sucker formation, in which sucker buds are generated from a ridge structure (sucker field ridge) on the oral side at the distal-most arm tip, was shared in both cuttlefish species, although some minor heterochronic shifts of the developmental events were detected between the two species.

scholarly journals Patterns of sucker development in cuttlefishes

2020 ◽  
Author(s):  
Ryosuke Kimbara ◽  
Mayuko Nakamura ◽  
Kohei Oguchi ◽  
Hisanori Kohtsuka ◽  
Toru Miura
Keyword(s):  
Developmental Process ◽  
Morphological Characteristics ◽  
Life Time ◽  
Postembryonic Development ◽  
Life History Strategies ◽  
Epithelial Tissue ◽  
Ridge Structure ◽  
Oral Side ◽  
Sepia Esculenta ◽  
Morphological Novelties

Abstract Background : Morphological novelties have been acquired through evolutionary processes in relation to the acquisition of new life-history strategies together with novel functions of bodyparts. Cephalopod molluscs such as octopuses, squids and cuttlefishes possess novel morphological characteristics such as their overall bodyplans and numerous arms. Among those novel morphologies, in particular, suckers arranged along the oral side of each arm possess multiple functions, such as capturing prey and locomotion, so that the sucker morphology is diversified among species, depending on their ecological niche. However, the detailed developmental process of sucker formation has remained unclear, although it is known that new suckers are formed or added throughout their life-time, including during both embryonic and postembryonic development. In the present study, therefore, focusing on two cuttlefish species, Sepia esculenta and S. lycidas ,in which the sucker morphology is relatively simple, morphological and histological observations were carried out during embryonic and postembryonic development to elucidate the developmental process of sucker formation. Results : The observations in both species clearly showed that the newly formed suckers were added on the oral side of the most distal tip of each arm during embryonic and postembryonic development. On the oral side of the arm tip, the epithelial tissue became swollen to form a ridge along the proximal-distal axis (distal sucker ridge). Next to the distal ridge, there were small dome-shaped bulges that are presumed to be the sucker primordia. Toward the proximal direction, the primordia became functional suckers, in which the inner tissues differentiated to form the complex sucker structures. During postembryonic development, on both sides of the distal sucker ridge, epithelial tissues extended to form a sheath, covering the ridge for protection of undifferentiated suckers. Conclusions : The developmental process of sucker formation, in which sucker primordia are generated from a ridge structure (distal sucker ridge) on the oral side at the distal-most arm tip, was shared in both cuttlefish species.

scholarly journals Multi-scale environmental filters and niche partitioning govern the distributions of riparian vegetation guilds

2014 ◽  
Author(s):  
Nate W Hough-Snee ◽  
Brian Laub ◽  
David M. Merritt ◽  
A. Lexine Long ◽  
Lloyd L. Nackley ◽  
...  
Keyword(s):  
Life History ◽  
Regional Climate ◽  
Morphological Characteristics ◽  
Species Traits ◽  
Life History Strategies ◽  
Rooting Depth ◽  
Environmental Filters ◽  
Support Tool ◽  
Channel Form ◽  
Riparian Plant

Across landscapes, riparian plant communities assemble under varying levels of disturbance, environmental stress, and resource availability, leading to the development of distinct riparian life-history guilds. Identifying the environmental filters that exert selective pressures and favor specific vegetation guilds within riverscapes is a critical step in setting baseline expectations for how riparia may respond to the environmental conditions anticipated under future global change scenarios. In this study, we ask (1) what functional riparian plant guilds exist across two major North American river basins? (2) What environmental filters shape riparian guild distributions? (3) Does resource partitioning between guilds influence guild distributions and co-occurrence? We identified riparian plant guilds, examining relationships between regional climate and watershed hydrogeomorphic characteristics, stream channel form, and co-occurring riparian guilds. Woody species composition was measured at 703 streams and each species’ traits were extracted from a database in five functional areas: life form, persistence and growth, reproduction, and resource use. We clustered species into guilds by morphological characteristics and attributes related to environmental tolerances, modeling guild distributions as a product of environmental filters (stressors and resources) and guild co-existence. We identified five guilds, i) a tall, deeply rooted, long-lived, evergreen tree guild, ii) a xeric disturbance tolerant shrub guild, iii) a hydrophytic, thicket-forming shrub guild, iv) a low-statured, shade-tolerant, understory shrub guild and v) a flood tolerant, mesoriparian shrub guild. Guilds were most strongly discriminated by one another species’ rooting depth, canopy height and potential to resprout and grow following biomass-removing disturbance. Hydro-climatic variables including precipitation, watershed area, water table depth, and channel form attributes reflective of hydrologic regime were predictors of guilds whose life history strategies had affinity or aversion to flooding, drought, and fluvial disturbance. Biotic interactions excluded guilds with divergent life history strategies and/or allowed for the co-occurrence of guilds that partition resources differently in the same environment. We conclude that riparian guilding provides a useful framework for assessing how disturbance and bioclimatic gradients shape riparian functional plant diversity. Multiple processes should be considered when the riparian response guilds framework is to be used as a land-use decision-support tool framework

scholarly journals Structural plasticity and isolation of umbilical cord progenitor cells of agouti (Dasyprocta prymnolopha) raised in captivity

2019 ◽  
Vol 40 (1) ◽  
pp. 225
Author(s):  
Maria Acelina Martins de Carvalho ◽  
Napoleão Martins Argôlo-Neto ◽  
Elís Rosélia Dutra de Freitas Siqueira Silva ◽  
Yulla Klinger de Carvalho Leite ◽  
Gerson Tavares Pessoa ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Progenitor Cells ◽  
Umbilical Cord ◽  
Morphological Characteristics ◽  
Muscle Fibres ◽  
Epithelial Tissue ◽  
Anatomical Site ◽  
In Captivity ◽  
Medium Layer

The agouti has been used as an experimental model in several studies focused on reproductive biology. The umbilical cord, an embryonic attachment that connects the foetus to the placenta, has been reported as an important anatomical site for obtaining stem cells. The objective of this study was to describe macro- and microscopically the umbilical cord of agoutis at different stages of gestation, to expand and cultivate in vitro the progenitor cells and to report their morphological characteristics. Seven cutias were submitted to caesarean section to collect the umbilical cords: five were destined for studies of cord structure in different stages of gestation (30, 35, 50, 75 and 100 days postcoital), and two were collected in the third stage of gestation for isolation and cell culture. The umbilical cord of cutias assumes a spiral arrangement, with veins and arteries on it starting 50 days after coitus. The arteries present an outer layer of smooth muscle fibres in a longitudinal and circular arrangement and a medium layer of smooth muscle fibres with only longitudinal and intimate orientation and coated by the endothelium. The veins consist of longitudinal smooth muscle fibres with an extract of smooth muscle cells, and the endothelium, in all analysed gestational phases, is a structure bounded by simple pavement epithelial tissue originating from the amnion, adhered to Wharton's Jelly and forming the umbilical vessels and allantoid duct. The proposed protocol allowed the collection of a high cellular concentration of umbilical cord progenitor cells from viable cutias.

scholarly journals Rediscovery of the ‘extinct’ bee Hesperocolletes douglasi Michener, 1965 (Colletidae: Colletinae: Paracolletini) in Western Australia and first description of the female

2019 ◽  
Vol 11 (3) ◽  
pp. 13310-13319 ◽  
Author(s):  
Juliana Pille Arnold ◽  
Mark V. Murphy ◽  
Raphael K. Didham ◽  
Terry F. Houston
Keyword(s):  
Western Australia ◽  
Ecological Niche ◽  
Morphological Characteristics ◽  
Biodiversity Hotspot ◽  
Pollen Load ◽  
Female Specimen ◽  
Potential Habitat ◽  
Insect Pollinators ◽  
Global Biodiversity

The second known specimen of the bee Hesperocolletes douglasi Michener, 1965 is here reported as a serendipitous find among a collection of insect pollinators from an isolated woodland remnant in the Southwest Floristic Region of Western Australia.  The unique male holotype of this monotypic genus of bees was collected 80 years ago and officially gazetted as presumed extinct in 1994.  With our collection of a female specimen in 2015, however, it now appears that H. douglasi may persist as an extant localised population.  Follow-up efforts to find more specimens at the collection locality so far proved unsuccessful, indicating that the species is likely either very rare or inhabits an ecological niche that is yet to be discovered.  Analysis of the pollen load carried by the female indicates that the species may be polylectic.  We discuss the context of the rediscovery of the bee, provide a detailed description and illustrations of the female, and make observations about the unusual morphological characteristics of the species.  The rediscovery of H. douglasi emphasizes the importance of conservation efforts for remnant woodlands in the region, both as potential habitat for the bee and as remaining habitat essential for other rare and threatened species in this global biodiversity hotspot. 

scholarly journals Multi-scale environmental filters and niche partitioning govern the distributions of riparian vegetation guilds

2015 ◽  
Author(s):  
Nate Hough-Snee ◽  
Brian Laub ◽  
David M. Merritt ◽  
A. Lexine Long ◽  
Lloyd L. Nackley ◽  
...  
Keyword(s):  
Life History ◽  
Regional Climate ◽  
Morphological Characteristics ◽  
Species Traits ◽  
Life History Strategies ◽  
Rooting Depth ◽  
Environmental Filters ◽  
Support Tool ◽  
Channel Form ◽  
Riparian Plant

Across landscapes, riparian plant communities assemble under varying levels of disturbance, environmental stress, and resource availability, leading to the development of distinct riparian life-history guilds. Identifying the environmental filters that exert selective pressures and favor specific vegetation guilds within riverscapes is a critical step in setting baseline expectations for how riparia may respond to the environmental conditions anticipated under future global change scenarios. In this study, we ask (1) what functional riparian plant guilds exist across two major North American river basins? (2) What environmental filters shape riparian guild distributions? (3) Does resource partitioning between guilds influence guild distributions and co-occurrence? We identified riparian plant guilds, examining relationships between regional climate and watershed hydrogeomorphic characteristics, stream channel form, and co-occurring riparian guilds. Woody species composition was measured at 703 streams and each species’ traits were extracted from a database in five functional areas: life form, persistence and growth, reproduction, and resource use. We clustered species into guilds by morphological characteristics and attributes related to environmental tolerances, modeling guild distributions as a product of environmental filters (stressors and resources) and guild co-existence. We identified five guilds, i) a tall, deeply rooted, long-lived, evergreen tree guild, ii) a xeric disturbance tolerant shrub guild, iii) a hydrophytic, thicket-forming shrub guild, iv) a low-statured, shade-tolerant, understory shrub guild and v) a flood tolerant, mesoriparian shrub guild. Guilds were most strongly discriminated by one another species’ rooting depth, canopy height and potential to resprout and grow following biomass-removing disturbance. Hydro-climatic variables including precipitation, watershed area, water table depth, and channel form attributes reflective of hydrologic regime were predictors of guilds whose life history strategies had affinity or aversion to flooding, drought, and fluvial disturbance. Biotic interactions excluded guilds with divergent life history strategies and/or allowed for the co-occurrence of guilds that partition resources differently in the same environment. We conclude that riparian guilding provides a useful framework for assessing how disturbance and bioclimatic gradients shape riparian functional plant diversity. Multiple processes should be considered when the riparian response guilds framework is to be used as a land-use decision-support tool framework

scholarly journals Life Without Thyroid Hormone Receptor

Endocrinology ◽  
2021 ◽  
Vol 162 (4) ◽  
Author(s):  
Yun-Bo Shi
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormone Receptor ◽  
Developmental Process ◽  
Gene Knockout ◽  
Postembryonic Development ◽  
Vertebrate Development ◽  
Animal Development ◽  
Necessary And Sufficient ◽  
Inducible Genes ◽  
T3 Receptors

Abstract Thyroid hormone (T3) is critical not only for organ function and metabolism in the adult but also for animal development. This is particularly true during the neonatal period when T3 levels are high in mammals. Many processes during this postembryonic developmental period resemble those during amphibian metamorphosis. Anuran metamorphosis is perhaps the most dramatic developmental process controlled by T3 and affects essentially all organs/tissues, often in an organ autonomous manner. This offers a unique opportunity to study how T3 regulates vertebrate development. Earlier transgenic studies in the pseudo-tetraploid anuran Xenopus laevis revealed that T3 receptors (TRs) are necessary and sufficient for mediating the effects of T3 during metamorphosis. Recent gene knockout studies with gene-editing technologies in the highly related diploid anuran Xenopus tropicalis showed, surprisingly, that TRs are not required for most metamorphic transformations, although tadpoles lacking TRs are stalled at the climax of metamorphosis and eventually die. Analyses of the changes in different organs suggest that removal of TRs enables premature development of many adult tissues, likely due to de-repression of T3-inducible genes, while preventing the degeneration of tadpole-specific tissues, which is possibly responsible for the eventual lethality. Comparison with findings in TR knockout mice suggests both conservation and divergence in TR functions, with the latter likely due to the greatly reduced need, if any, to remove embryo/prenatal-specific tissues during mammalian postembryonic development.

Features of skeletal muscle structure in Smena-8 and Andalusian Blue chickens in separate periods of postembryonic ontogenesis

2021 ◽  
Vol 1 (4) ◽  
pp. 6-15
Author(s):  
G. V. Kondratov ◽  
◽  
V. V. Stepanishin ◽  
S. G. Kumirov ◽  
◽  
...  
Keyword(s):  
Skeletal Muscles ◽  
Animal Species ◽  
Striated Muscle ◽  
Muscle Fibers ◽  
Morphological Characteristics ◽  
Pectoral Muscle ◽  
Postembryonic Development ◽  
Quadriceps Femoris ◽  
Connective Tissue Component ◽  
Meat Productivity

Histological and morphological characteristics of skeletal muscles in chickens of the meat direction of productivity Smena-8 and egg direction of productivity Andalusian blue on the 20th and 29th days of postembryonic development are presented. The skeletal striated muscle tissue of the studied bird obeys the general principles of myogenesis inherent in most animal species and is characterized by signs of a definitive structure. It is shown that on the 20th and 29th days of postembryonic ontogenesis in the Smena-8 cross and the Andalusian blue breed, the quadriceps femoris is ahead of the superficial pectoral muscle in terms of the thickness of muscle fibers. The thickness of the endomysium and perimysium in the connective tissue component of the superficial pectoral muscle in chickens of both directions of productivity prevails over that in the quadriceps femoris. Based on the obtained morphometric parameters of the structure of muscle fibers, the concept of myogenesis of skeletal muscles in agricultural poultry of egg and meat productivity directions is presented.

Bacterial symbionts induce host organ morphogenesis during early postembryonic development of the squid Euprymna scolopes

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1719-1729 ◽  
Author(s):  
M.K. Montgomery ◽  
M. McFall-Ngai
Keyword(s):  
Vibrio Fischeri ◽  
Bacterial Species ◽  
Experimental System ◽  
Postembryonic Development ◽  
Surface Epithelium ◽  
Epithelial Tissue ◽  
Bacterial Symbionts ◽  
Euprymna Scolopes ◽  
Epithelial Surface ◽  
Animal Development

The mutualistic association between the squid Euprymna scolopes and the bacterium Vibrio fischeri is an emerging experimental system for the study of the influence of bacteria on animal development. Taking advantage of the ability to raise both this host and its microbial partner independently under laboratory conditions, we describe the effects of bacterial interactions on morphogenesis of the juvenile host symbiotic organ. Our results show that bacteria are essential for normal postembryonic development of the symbiotic organ, which involves changes in both the surface epithelium and the epithelial tissue within the organ where the bacterial culture will take up residence. Cell death induced by exposure to symbiotic V. fischeri results in the regression of a complex ciliated surface epithelium, a tissue that apparently functions to facilitate inoculation of the juvenile organ with the appropriate specific bacterial species. Regression of this tissue begins within hours of exposure to symbiosis-competent bacteria and progresses over the next 5 days, at which time full regression is complete, resulting in a symbiotic organ whose epithelial surface resembles that of the fully mature organ. Moreover, symbiosis-competent bacteria induce modification of the epithelial cells of the crypts that will house these symbionts; these cells undergo significant changes in shape and size in response to interactions with symbiotic V. fischeri. In contrast, we find that when these tissues are not exposed to the proper bacterial symbionts they remain in a state of arrested morphogenesis, a condition that can be rescued by interactions with symbionts. The results of these studies are the first experimental data demonstrating that a specific bacterial symbiont can play an inductive role in animal development.

Mycetophagy in Filenchus misellus (Andrássy, 1958) Lownsbery & Lownsbery, 1985 (Nematoda: Tylenchidae), with notes on its morphology

Nematology ◽  
2002 ◽  
Vol 4 (7) ◽  
pp. 795-801 ◽  
Author(s):  
Ikuo Kadota ◽  
Takao Tsukiboshi ◽  
Hiroaki Okada
Keyword(s):  
Population Growth ◽  
Growth Rates ◽  
Agaricus Bisporus ◽  
Morphological Characteristics ◽  
Pythium Ultimum ◽  
Fungal Species ◽  
Life History Strategies ◽  
Population Growth Rates ◽  
Species Population ◽  
Northern Japan

AbstractPopulation growth rates on fungal colonies and morphological characteristics were investigated in a member of the genus Filenchus (Tylenchidae) collected from decomposing rice straw in Fukushima-city, northern Japan. The nematode was identified as F. misellus on the basis of the great similarity in morphological measurements to the known populations of the species. Population growth rates were measured 40 days after inoculating nematodes on to seven fungal species cultured in Petri dishes at 25oC. Growth rates were high on Chaetomium globosum and Coprinus cinereus, intermediate on Pleurotus ostreatus and Rhizoctonia solani and low on Agaricus bisporus, Fusarium oxysporum and Pythium ultimum. The ability of the nematode to feed on fungi in decomposing organic matter suggests the possibility for alternative life history strategies and greater ecological amplitude for members of Filenchus and other genera of Tylenchidae.

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