scholarly journals From swimming towards sessility in two metamorphoses – the drastic changes in structure and function of the nervous system of the bay barnacle Amphibalanus improvisus (Crustacea, Thecostraca, Cirripedia) during development

2020 ◽  
Vol 89 (3) ◽  
pp. 324-352
Author(s):  
Paul Kalke ◽  
Thomas Frase ◽  
Stefan Richter
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Nerve Cord ◽  
Laser Scanning ◽  
Ventral Nerve Cord ◽  
Developmental Stages ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Compound Eyes ◽  
Cephalic Shield

Knowledge about the development of the nervous system in cirripeds is limited, particularly with regard to the changes that take place during the two metamorphoses their larvae undergo. This study delivers the first detailed description of the development of the nervous system in a cirriped species, Amphibalanus improvisus by using immunohistochemical labeling against acetylated alpha-tubulin, and confocal laser scanning microscopy. The development of the nervous system in the naupliar stages corresponds largely to that in other crustaceans. As development progresses, the protocerebral sensory organs differentiate and the intersegmental nerves forming the complex peripheral nervous system appear, innervating the sensory structures of the cephalic shield. During metamorphosis into a cypris the lateral sides of the cephalic shield fold down into a bilateral carapace, which leads to a reorganization of the peripheral nervous system. The syncerebrum of the cypris exhibits the highest degree of complexity of all developmental stages, innervating the frontal filaments, nauplius eye, compound eyes and the antennules. During settlement, when the second metamorphosis occur, the closely associated frontal filaments and compound eyes are shed together with the cuticle of the carapace and the antennules. In adults, the syncerebral structures are reduced while the ventral nerve cord and the peripheral nervous system increase in complexity. The peripheral nervous system plays an important role in processing sensory input and also in settlement. In summary, through the larval development we observed a structural and thus also functional increase of complexity in favor of the peripheral nervous system and the ventral nerve cord.

scholarly journals Histaminergic interneurons in the ventral nerve cord: assessment of their value for Euarthropod phylogeny

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Maite Maurer ◽  
Janina Hladik ◽  
Thomas M. Iliffe ◽  
Torben Stemme
Keyword(s):  
Nerve Cord ◽  
Laser Scanning ◽  
Ventral Nerve Cord ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Sequence Information ◽  
Histaminergic Neurons ◽  
Character Set ◽  
Phylogenetic Hypotheses ◽  
Structural Aspects

AbstractDespite numerous approaches to the resolution of euarthropod phylogeny, mainly based on modern sequence information and traditional external morphology, the resulting hypotheses are often contradictory and leave many questions about euarthropod evolution unanswered. The comparison of developmental and structural aspects of the nervous system has shown to be a valuable contribution to the assessment of current phylogenetic hypotheses. One promising approach for the generation of new character sets is the morphology of transmitter systems and the discovery of individually identifiable neurons, which allow phylogenetic comparisons on the single cell level. In this context, the serotonin transmitter system has been investigated to a considerable degree. Studies to date have yielded important stimuli to our understanding of euarthropod relationships and the evolution of their nervous systems. However, data on other transmitter systems remain fragmented, and their value with respect to phylogenetic questions remains speculative. The biogenic amine histamine is a promising transmitter; a substantial amount of data has been reported in the literature and the homology of some histaminergic neurons has been suggested. Here, we present a comprehensive review of histaminergic neurons in the ventral nerve cord of Euarthropoda. Using immunocytochemical labeling of histamine combined with confocal laser-scanning microscopy, we investigated the transmitter system in phylogenetically relevant taxa, such as Zygentoma, Remipedia, Diplopoda, and Arachnida. By reconstructing ground patterns, we evaluated the significance of this specific character set for euarthropod phylogeny. With this approach, we identified a set of neurons, which can be considered homologous within the respective major taxon. In conclusion, the histaminergic system contains useful information for our understanding of euarthropod phylogeny, supporting the proposed clades Tetraconata and Mandibulata. Furthermore, this character set has considerable potential to help resolve relationships within the major clades at a deeper level of taxonomy, due to the considerable variability in neurite morphology.

scholarly journals Protocol for rapid clearing and staining of fixed Arabidopsis ovules for improved imaging by confocal laser scanning microscopy

Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Rachele Tofanelli ◽  
Athul Vijayan ◽  
Sebastian Scholz ◽  
Kay Schneitz
Keyword(s):  
Laser Scanning ◽  
Developmental Stages ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Imaging Data ◽  
Model Species ◽  
Cellular Models ◽  
Cellular Resolution

Abstract Background A salient topic in developmental biology relates to the molecular and genetic mechanisms that underlie tissue morphogenesis. Modern quantitative approaches to this central question frequently involve digital cellular models of the organ or tissue under study. The ovules of the model species Arabidopsis thaliana have long been established as a model system for the study of organogenesis in plants. While ovule development in Arabidopsis can be followed by a variety of different imaging techniques, no experimental strategy presently exists that enables an easy and straightforward investigation of the morphology of internal tissues of the ovule with cellular resolution. Results We developed a protocol for rapid and robust confocal microscopy of fixed Arabidopsis ovules of all stages. The method combines clearing of fixed ovules in ClearSee solution with marking the cell outline using the cell wall stain SCRI Renaissance 2200 and the nuclei with the stain TO-PRO-3 iodide. We further improved the microscopy by employing a homogenous immersion system aimed at minimizing refractive index differences. The method allows complete inspection of the cellular architecture even deep within the ovule. Using the new protocol we were able to generate digital three-dimensional models of ovules of various stages. Conclusions The protocol enables the quick and reproducible imaging of fixed Arabidopsis ovules of all developmental stages. From the imaging data three-dimensional digital ovule models with cellular resolution can be rapidly generated using image analysis software, for example MorphographX. Such digital models will provide the foundation for a future quantitative analysis of ovule morphogenesis in a model species.

Confocal Laser Microscopy of Physiologically Characterized Fluorescently Labeled Central Nervous System Neurons

1988 ◽  
Vol 46 ◽  
pp. 274-275
Author(s):  
J.N. Turner ◽  
J. Swann ◽  
K. Smith ◽  
M. Siemens ◽  
D. Szarowski ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Laser Scanning ◽  
Tissue Sample ◽  
Lucifer Yellow ◽  
Single Cells ◽  
Brain Slices ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Efficient Detection

Confocal laser scanning microscopy (CLSM) is capable of three-dimensional imaging of fluorescently labeled single cells. Efficient detection via a photomultiplier and optical sectioning with high rejection of light from other specimen levels make it possible to image cells surrounded by either labeled or unlabeled tissue. It is no longer necessary to restrict high resolution light microscopy to cultured cells or those near the surface of a tissue sample. Cells can be observed üin situ” in a physiologically characterized environment. Central nervous system neurons can be electrophysiologically characterized and then injected with a fluorescent dye such as lucifer yellow. The CLSM can excite the dye and image the fluorescent emission in thick tissue preparations (hundreds of micrometers) making possible a new approach to the correlation of physiology and anatomy.Brain slices 350 μm thick were obtained from hippocampus and inferior colliculus of immature rats and incubated in oxygenated artificial cerebrospinal fluid. Cells were penetrated with micropipets, characterized electrophysiologically and ionophoretically injected with 5% lucifer yellow in LiAc.

scholarly journals Heparin Inhibits Leukocyte Rolling in Pial Vessels and Attenuates Inflammatory Changes in a Rat Model of Experimental Bacterial Meningitis

1997 ◽  
Vol 17 (11) ◽  
pp. 1221-1229 ◽  
Author(s):  
Joerg R. Weber ◽  
Klemens Angstwurm ◽  
Thomas Rosenkranz ◽  
Ute Lindauer ◽  
Dorette Freyer ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Bacterial Meningitis ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Leukocyte Rolling ◽  
Central Nervous System Inflammation ◽  
Inflammatory Processes

Heparin is a natural proteoglycan that was first described in 1916. In addition to its well characterized effect on blood coagulation, it is becoming clear that heparin also modulates inflammatory processes on several levels, including the interference with leukocyte–endothelium interaction. Anecdotal observations suggest a better clinical outcome of heparin-treated patients with bacterial meningitis. The authors demonstrate that heparin, a glycosaminoglycan, inhibits significantly in the early phase of experimental pneumococcal meningitis the increase of 1) regional cerebral blood flow (125 ± 18 versus 247 ± 42%), 2) intracranial pressure (4.5 ± 2.0 versus 12.1 ± 2.2 mm Hg), 3) brain edema (brain water content: 78.23 ± 0.33 versus 79.49 ± 0.46%), and 4) influx of leukocytes (571 ± 397 versus 2400 ± 875 cells/μL) to the cerebrospinal fluid compared with untreated rats. To elucidate the possible mechanism of this observation, the authors investigated for the first time leukocyte rolling in an inflammatory model in brain venules by confocal laser scanning microscopy in vivo. Heparin significantly attenuates leukocyte rolling at 2, 3, and 4 hours (2.8 ± 1.3 versus 7.9 ± 3.2/100 μm/min), as well as leukocyte sticking at 4 hours (2.1 ± 0.4 versus 3.5 ± 1.0/100 μm/min) after meningitis induction compared with untreated animals. The authors conclude that heparin can modulate acute central nervous system inflammation and, in particular, leukocyte–endothelium interaction, a key process in the cascade of injury in bacterial meningitis. They propose to evaluate further the potential of heparin in central nervous system inflammation in basic and clinical studies.

scholarly journals Ovule Development and in Planta Transformation of Paphiopedilum Maudiae by Agrobacterium-Mediated Ovary-Injection

2020 ◽  
Vol 22 (1) ◽  
pp. 84
Author(s):  
Bai-Xue Luo ◽  
Li Zhang ◽  
Feng Zheng ◽  
Kun-Lin Wu ◽  
Lin Li ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Developmental Stages ◽  
Embryo Sac ◽  
Mature Embryo ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pcr Analysis ◽  
In Planta Transformation ◽  
In Planta ◽  
Hygromycin Selection

In this paper, the development of the Paphiopedilum Maudiae embryo sac at different developmental stages after pollination was assessed by confocal laser scanning microscopy. The mature seeds of P. Maudiae consisted of an exopleura and a spherical embryo, but without an endosperm, while the inner integument cells were absorbed by the developing embryo. The P. Maudiae embryo sac exhibited an Allium type of development. The time taken for the embryo to develop to a mature sac was 45-50 days after pollination (DAP) and most mature embryo sacs had completed fertilization and formed zygotes by about 50–54 DAP. In planta transformation was achieved by injection of the ovaries by Agrobacterium, resulting in 38 protocorms or seedlings after several rounds of hygromycin selection, corresponding to 2, 7, 5, 1, 3, 4, 9, and 7 plantlets from Agrobacterium-mediated ovary-injection at 30, 35, 42, 43, 45, 48, 50, and 53 DAP, respectively. Transformation efficiency was highest at 50 DAP (2.54%), followed by 2.48% at 53 DAP and 2.45% at 48 DAP. Four randomly selected hygromycin-resistant plants were GUS-positive after PCR analysis. Semi-quantitative PCR and quantitative real-time PCR analysis revealed the expression of the hpt gene in the leaves of eight hygromycin-resistant seedlings following Agrobacterium-mediated ovary-injection at 30, 35, 42, 43, 45, 48, 50, and 53 DAP, while hpt expression was not detected in the control. The best time to inject P. Maudiae ovaries in planta with Agrobacterium is 48-53 DAP, which corresponds to the period of fertilization. This protocol represents the first genetic transformation protocol for any Paphiopedilum species and will allow for expanded molecular breeding programs to introduce useful and interesting genes that can expand its ornamental and horticulturally important characteristics.

scholarly journals Extracellular excystation and development of Cryptosporidium: tracing the fate of oocysts within Pseudomonas aquatic biofilm systems

2021 ◽  
Author(s):  
Wan Koh ◽  
Andrew Thompson ◽  
Hanna Edwards ◽  
Paul Monis ◽  
Peta L Clode
Keyword(s):  
Laser Scanning ◽  
Distribution Systems ◽  
Water Distribution ◽  
Developmental Stages ◽  
Parasitophorous Vacuole ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Growth Environment ◽  
Flow Cytometric ◽  
Harsh Conditions

Background Aquatic biofilms often serve as environmental reservoirs for microorganisms and provide them with a nutrient-rich growth environment under harsh conditions. With regard to Cryptosporidium, biofilms can serve as environmental reservoirs for oocysts, but may also support the growth of additional Cryptosporidium stages. Results Here we used confocal laser scanning microscopy, scanning electron microscopy (SEM), and flow cytometry to identify and describe various Cryptosporidium developmental stages present within aquatic biofilm systems, and to directly compare these to stages produced in cell culture. We also show that Cryptosporidium has the ability to form a parasitophorous vacuole independently, in a host-free biofilm environment, potentially allowing them to complete an extracellular life cycle. Correlative data from confocal and SEM imaging of the same cells confirmed that the observed developmental stages (including trophozoites, meronts, and merozoites) were Cryptosporidium. These microscopy observations were further supported by flow cytometric analyses, where excysted oocyst populations were detected in 1, 3 and 6 day-old Cryptosporidium-exposed biofilms, but not in biofilm-free controls. Conclusions These observations not only highlight the risk that aquatic biofilms pose in regards to Cryptosporidium outbreaks from water distribution systems, but further indicate that even simple biofilms are able to stimulate oocyst excystation and support the extracellular multiplication and development of Cryptosporidium within aquatic environments.

Sign in / Sign up

Export Citation Format

Share Document