scholarly journals Diversity in the Development of the Neuromuscular System of Nemertean Larvae (Nemertea, Spiralia)

2021 ◽  
Vol 9 ◽  
Author(s):  
Jörn von Döhren

In studies on the development of nervous systems and musculature, fluorescent labeling of neuroactive substances and filamentous actin (f-actin) of muscle cells and the subsequent analysis with confocal laser scanning microscopy (CLSM), has led to a broad comparative data set for the majority of the clades of the superphylum Spiralia. However, a number of clades remain understudied, which results in gaps in our knowledge that drastically hamper the formulation of broad-scale hypotheses on the evolutionary developmental biology (EvoDevo) of the structures in question. Regarding comparative data on the development of the peptidergic nervous system and the musculature of species belonging to the spiralian clade Nemertea (ribbon worms), such considerable knowledge gaps are manifest. This paper presents first findings on fluorescent labeling of the FMRFamide-like component of the nervous system and contributes additional data on the muscle development in the presently still underrepresented larvae of palaeo- and hoplonemertean species. Whereas the architecture of the FMRFamide-like nervous system is comparably uniform between the studied representatives, the formation of the musculature differs considerably, exhibiting developmental modes yet undescribed for any spiralian species. The presented results fill a significant gap in the spiralian EvoDevo data set and thus allow for further elaboration of hypotheses on the ancestral pattern of the musculature and a prominent component of the nervous system in Nemertea. However, with respect to the variety observed, it is expected that the true diversity of the developmental pathways is still to be discovered when more detailed data on other nemertean species will be available.

2000 ◽  
Vol 20 (1) ◽  
pp. 7-15 ◽  
Author(s):  
R. Heintzmann ◽  
G. Kreth ◽  
C. Cremer

Fluorescent confocal laser scanning microscopy allows an improved imaging of microscopic objects in three dimensions. However, the resolution along the axial direction is three times worse than the resolution in lateral directions. A method to overcome this axial limitation is tilting the object under the microscope, in a way that the direction of the optical axis points into different directions relative to the sample. A new technique for a simultaneous reconstruction from a number of such axial tomographic confocal data sets was developed and used for high resolution reconstruction of 3D‐data both from experimental and virtual microscopic data sets. The reconstructed images have a highly improved 3D resolution, which is comparable to the lateral resolution of a single deconvolved data set. Axial tomographic imaging in combination with simultaneous data reconstruction also opens the possibility for a more precise quantification of 3D data. The color images of this publication can be accessed from http://www.esacp.org/acp/2000/20‐1/heintzmann.htm. At this web address an interactive 3D viewer is additionally provided for browsing the 3D data. This java applet displays three orthogonal slices of the data set which are dynamically updated by user mouse clicks or keystrokes.


1993 ◽  
Vol 71 (5) ◽  
pp. 725-731 ◽  
Author(s):  
Harry M. P. Kengen ◽  
Ton van Amstel ◽  
Bart Knuiman

Phalloidin labelled with trimethyl rhodamine isothiocyanate in extraction buffer was used to stain actin in suspension cells of tobacco. Confocal immunofluorescence microscopy indicated the presence of filamentous actin containing structures in interphase nuclei of elongating cells of Nicotiana tabacum ‘Bright Yellow 2 Go’. The results were not affected by the omission of DMSO from the extraction medium. These structures, called actin baskets, were present in about 20% of the cells after induced elongation and varied in size, shape, and number per nucleus. The cytoplasmic actin array remained intact. It is proposed that the baskets have a transient character and are related to differentiation. Key words: confocal laser scanning microscopy, elongation, F-actin, nucleus, protoplasts, TRITC–phalloidin.


Author(s):  
J.N. Turner ◽  
J. Swann ◽  
K. Smith ◽  
M. Siemens ◽  
D. Szarowski ◽  
...  

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.


1997 ◽  
Vol 17 (11) ◽  
pp. 1221-1229 ◽  
Author(s):  
Joerg R. Weber ◽  
Klemens Angstwurm ◽  
Thomas Rosenkranz ◽  
Ute Lindauer ◽  
Dorette Freyer ◽  
...  

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.


2013 ◽  
Vol 44 (3-4) ◽  
pp. 261-347 ◽  
Author(s):  
István Mikó ◽  
Lubomir Masner ◽  
Eva Johannes ◽  
Matthew J. Yoder ◽  
Andrew R. Deans

The skeletomuscular system of male terminalia in Evaniomorpha (Hymenoptera) is described and the functional morphology of male genitalia is discussed. Confocal laser scanning microscopy is the primary method used for illustrating anatomical phenotypes, and a domain-specific anatomy ontology is employed to more explicitly describe anatomical structures. A comprehensive data set of ceraphronoid male genitalia is analyzed, yielding the first phylogeny of the superfamily. One hundred and one taxa, including three outgroups, are scored for 48 characters. Ceraphronoidea are recovered as sister to the remaining Evaniomorpha in the implied weighting analyses. Numerous character states suggest that Ceraphronoidea is a relatively basal apocritan lineage. Ceraphronoidea, Ceraphronidae, and Megaspilinae are each retrieved as monophyletic in all analyses. Megaspilidae is not recovered as monophyletic. Lagynodinae is monophyletic in the implied weighting analyses with strong support and is a polytomy in the equal weighting analysis. Lagynodinae shares numerous plesiomorphies with both Megaspilinae and Ceraphronidae. Relationships among genera are weakly corroborated. Masner is sister of Ceraphronidae. Trassedia is nested within Ceraphronidae based on the present analysis. Because of this and numerous features shared between it and Ceraphron we transfer Trassedia from Megaspilidae to Ceraphronidae. Dendrocerus forms a single monophyletic clade, with modest support, together with some Conostigmus species. This result challenges the utility of such traditional diagnostic characters as ocellar arrangement and shape of the male flagellomeres. Aphanogmus is monophyletic in the implied weighting, but remains a polytomy with Ceraphron in the equal weighting analysis. Gnathoceraphron is always nested within a well-supported Aphanogmus clade. Cyoceraphron and Elysoceraphron are nested within Ceraphron and Aphanogmus, respectively. The male genitalia prove to be a substantial source of phylogenetically relevant information. Our results indicate that a reclassification of Ceraphronoidea both at the family and generic level is necessary but that more data are required.


2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Mirian Domenech ◽  
Ernesto García

ABSTRACT Acute otitis media, a polymicrobial disease of the middle ear cavity of children, is a significant public health problem worldwide. It is most frequently caused by encapsulated Streptococcus pneumoniae and nontypeable Haemophilus influenzae, although the widespread use of pneumococcal conjugate vaccines is apparently producing an increase in the carriage of nonencapsulated S. pneumoniae. Frequently, pneumococci and H. influenzae live together in the human nasopharynx, forming a self-produced biofilm. Biofilms present a global medical challenge since the inherent antibiotic resistance of their producers demands the use of large doses of antibiotics over prolonged periods. Frequently, these therapeutic measures fail, contributing to bacterial persistence. Here, we describe the development of an in vitro nonencapsulated S. pneumoniae-nontypeable H. influenzae biofilm system with polystyrene or glass-bottom plates. Confocal laser scanning microscopy and specific fluorescent labeling of pneumococcal cells with Helix pomatia agglutinin revealed an even distribution of both species within the biofilm. This simple and robust protocol of mixed biofilms was used to test the antimicrobial properties of two well-known antioxidants that are widely used in the clinical setting, i.e., N-acetyl-l-cysteine and cysteamine. This repurposing approach showed the high potency of N-acetyl-l-cysteine and cysteamine against mixed biofilms of nonencapsulated S. pneumoniae and nontypeable H. influenzae. Decades of clinical use mean that these compounds are safe to use, which may accelerate their evaluation in humans.


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