Novel aspects of the nervous system of Bonellia viridis (Echiura) revealed by the combination of immunohistochemistry, confocal laser-scanning microscopy and three-dimensional reconstruction

The Echiura have been placed in close phylogenetic affinity to the Annelida on the basis of numerous homologous characters including the mode of development, the nearly identical formation of a trochophore larva, as well as the development and ultrastructure of chaetae and spermatozoa. Furthermore, phylogenetic analysis of elongation factor-1 gene sequences supports placement of the Echiura within the Annelida. Nevertheless, the Echiura are generally excluded from the Annelida due to their lack of segmentation. However, it must be considered that this lack could represent a secondary condition and that Echiura are derived from formerly segmented ancestors. In the present study, the combination of methods applied reveals several novel aspects of the central nervous system in developmental stages of Bonellia viridis. The most important of these is the metameric organization of the ventral nerve cord. Antibodies against different neurotransmitters label discrete repetitive units of perikarya in the ventral nerve cord. This organisation is additionally supported by the distribution of peripheral nerves as shown by labelling of neurotubules. These nerves are clearly paired and are evenly distributed, corresponding to the serial units of serotoninergic neurons. Different methods of computer-aided three-dimensional reconstruction display the precise spatial distribution of perikarya and peripheral nerves allowing the repetitive units to be discerned on the basis of relative size, position and number of labelled cells. The repetitive units in the nervous system of B. viridis correspond to segmental ganglia of various Annelida and are interpreted as an indication that Echiura are derived from formerly segmented ancestors, thus supporting the systematic inclusion of the Echiura within the Annelida.     

Phylogenetic position of Sipuncula derived from multi‐gene and phylogenomic data and its implication for the evolution of segmentation

The phylogenetic position of Sipuncula, a group of unsegmented marine worms, has been controversial for several decades: Especially based on morphological data, closer relationships to Mollusca or Annelida were among the most favoured hypotheses. Increasing amounts of molecular data in recent years have consistently placed Sipuncula either in close affinity to or even within Annelida, the segmented worms, and rejected a close relationship to Mollusca. Yet, it remained uncertain whether Sipuncula is the sister group of Annelida or an annelid subtaxon. Therefore, herein we gathered data for five nuclear genes, which have been rarely used regarding Annelida and Sipuncula, and combined these with data for six previously used genes to further elucidate the phylogenetic position of Sipuncula. We also compiled a data set for 78 ribosomal proteins from publicly available genomic data sets. These are the two largest data sets for annelids with more than 10 taxa to date. All analyses placed Sipuncula within Annelida. For the first time, topology tests significantly rejected the possibility that Sipuncula is sister to Annelida. Thus, our analyses revealed that Sipuncula had secondarily lost segmentation. Given that unsegmented Echiura is also an annelid subtaxon, segmentation, a key character of Annelida, is much more variable than previously thought. Yet, this conclusion does not support the hypothesis that the last common ancestor of Annelida, Arthropoda and Chordata was segmented, assuming several losses along the branches leading to them. As yet no traces of segmentation could be shown in taxa exhibiting serially organized organ systems such as certain Mollusca, while in Sipuncula and Echiura such traces could be demonstrated. An independent origin of segmentation in Annelida, Arthropoda and Chordata thus appears to be more plausible and parsimonious.     

Ultrastructural observations on spermiogenesis in the peanut worm,Themiste pyroides (Chamberlin, 1920) (Sipuncula; Sipunculidea)

Summary

The process of spermiogenesis and the ultrastructure of the spermatozoa in the peanut worm, Themiste pyroides, from the Sea of Japan were observed with electron microscopy (SEM and TEM). The testes are composed of groups of spermatogonia and are covered by peritoneal cells. Clusters of spermatocytes are released from the testes into the coelomic fluid. Connected by intercellular bridges, the spermatocytes within a given cluster develop asynchronously. Proacrosomal vesicles and a flagellum appear in spermatocytes. Spermatids in the clusters retain the intercellular connections. During spermiogenesis, the acrosomal vesicle, formed by coalescence of small proacrosomal vesicles in the basal part of the spermatid, migrates to the apical part of the cell to form a conical-shaped acrosome. The basal concavity lying above the nucleus is filled with subacrosomal substance. The midpiece contains four mitochondria, two centrioles, and some residual cytoplasm with dark glycogen-like granules. A peculiar annulus structure develops around the base of the flagellum. The distal centriole has a pericentriolar complex consisting of radially oriented elements. Before the spawning process, the spermatozoa are filtered throughout the ciliary nephrostomal funnel into the excretory sac of paired nephridia where they are stored for a short time. The sperm are released into the sea water via nephridiopores. Spermatozoa remaining in the coelomic fluid after spawning are resorbed by amoebocytes. This species from Vostok Bay is characterized by a prolonged spawning period from June to early October. The reproductive strategy of T. pyroides is discussed in comparison with that of Thysanocardia nigra, the latter having a unique pattern of packaging of the spermatozoa, resulting in the formation of spermatozeugmata, as a reproductive adaptation to the very short spawning period.     

Fine structure of the pharyngeal apparatus of the pelagosphera larva in Phascolosoma agassizii (Sipuncula) and its phylogenetic significance

Sipuncula is a small taxon of worm-like marine organisms of still uncertain phylogenetic position. Sipunculans are characterized by an unsegmented body composed of a trunk into which the anterior part, the introvert, can be withdrawn. The group has been placed at various positions within Metazoa; currently, it is either seen as sister group of a clade comprising Mollusca and Annelida or as sister to each of these. An in-group position in either Mollusca or Annelida has usually been precluded till now due to the lack of so-called annelid or molluscan “key-characters” such as segmentation and chaetae or the radula. In the development of certain taxa the trochophore stage is followed by a planktonic larva, the pelagosphera, which might exhibit phylogenetically important structures. Among these is the buccal organ, which has been considered homologous either to the ventral pharyngeal organ present in many sedentary polychaetes or to the radular apparatus of molluscs. In the present paper, the ventral pharynx of the pelagosphera larva of Phascolosoma agassizii is investigated by transmission electron microscopy. The pharynx comprises dorsolateral ciliary folds, a muscle bulb formed by transverse muscle fibres with large intercellular spaces, and an investing muscle. A tongue-like organ is lacking. These results show great structural correspondences to the ventral pharynx of polychaetes, especially to that of the flabelligerid Diplocirrus longisetosus. In contrast, there are no signs of structural similarities to the corresponding structures of molluscs. Thus evidence increases that Sipuncula are closely related to annelids; moreover, an in-group position of Sipuncula within Annelida, as suggested by recent molecular studies, is not precluded by the present data. Instead these studies find additional support. Hence the lack of segmentation and chitinous chaetae in Sipuncula would be a secondary rather than a primary situation, as has recently been shown for Echiura and Pogonophora.     

The simplicity of males: Dwarf males of four species of Osedax (Siboglinidae; Annelida) investigated by confocal laser scanning microscopy

Dwarf males of the bone‐eating worms Osedax (Siboglinidae, Annelida) have been proposed to develop from larvae that settle on females rather than on bone. The apparent arrest in somatic development and resemblance of the males to trochophore larvae has been posited as an example of paedomorphosis. Here, we present the first investigation of the entire muscle and nervous system in dwarf males of Osedax frankpressi, O. roseus, O. rubiplumus, and O. “spiral” analyzed by multistaining and confocal laser scanning microscopy. Sperm shape and spermiogenesis, the sperm duct and internal and external ciliary patterns were likewise visualized. The males of all four species possess morphological traits typical of newly settled siboglinid larvae: a prostomium, a peristomium with a prototroch, one elongate segment and a second shorter segment. Each segment has a ring of eight long‐handled hooked chaetae. The longitudinal muscles are distributed as evenly spaced strands forming a grid with the thin outer circular muscles. Oblique protractor and retractor muscles are associated with each of the chaetal sacs. The nervous system comprises a cerebral ganglion, a prototroch nerve ring, paired dorsolateral longitudinal nerves, five ventral longitudinal nerves with paired, posterior ganglia and a terminal commissure, as well as a net of fine peripheral transverse plexuses surrounding the first segment. Internal ciliation occurs as paired ventrolateral bands along the first segment. The bands appear to lead the free mature sperm to a ciliated duct and seminal vesicle lying just behind the prototroch region. A duct then runs from the seminal vesicle into the dorsal part of the prostomium. The similarity of Osedax males to the larvae of Osedax and other siboglinid annelids as well as similarities shown here to the neuromuscular organization seen in other annelid larvae supports the hypothesis of paedomorphosis in males of Osedax. J. Morphol., 2010. © 2009 Wiley‐Liss, Inc.     

Embryonic and larval development of the peanut worm Phascolosoma agassizii (Keferstein 1867) from the Sea of Japan (Sipuncula: Phascolosomatidea)

All stages of the embryonic and larval development of Phascolosoma agassizii from Peter the Great Bay (Sea of Japan) were studied and illustrated using light and electron microscopy. The eggs of P. agassizii have the form of an ellipsoid (long and short axes about 100 and 70?µm, respectively). Egg cleavage is typical, spiral, and unequal. Gastrulation occurs by epiboly. This species possesses two pelagic larval stages, a lecithotrophic trochophore and a planktotrophic pelagosphera. The transformation of trochophore into pelagosphera occurs 80–90?h after fertilization. After 120–180?h, the larva has developed all systems of organs characteristic of the pelagosphera and is capable of feeding. At day 10, pelagospheras can settle, for some time, on the aquarium bottom and move on a ciliated lip, collecting food with the aid of a buccal organ. In addition, the larvae periodically attach themselves to the aquarium bottom or to the surface film of the water by means of a terminal organ. The trunk of the larva elongates by enlargement of the region behind the dorsal anal opening, which is located almost in the middle of the trunk region in the 15-day old larva. In the laboratory, 1-month old larvae spend the greater part of time in the attached state. Being attached by a glandular terminal organ to the aquarium bottom, they characteristically bend the body, actively feeding on microalgae from the substratum surface. The differences in the development of P. agassizii in the isolated West-Pacific and East-Pacific populations are shown and discussed.     

Immunohistochemical analysis of nervous system regeneration in chimeric individuals of Dorvillea bermudensis (Polychaeta, Dorvilleidae)

In regeneration experiments, 0.5% of the two- or five-segmented fragments of the polychaete Dorvillea bermudensis were found unexpectedly transplanted: two fragments of each that were lying close together during the initial period, fused and regenerated a chimeric individual. Of the three theoretical possibilities (i.e. fusion of (i). two posterior ends; (ii). one anterior and one posterior end; (iii). or two anterior ends) only the last two were realized. The similarly oriented fragments regenerated a normal animal while anterior-anterior fused ones produced two heads or a double head. Whether the ventral cords of the fragments are located vis-à-vis or adjacent, influences the course of regeneration as well. Immunohistochemical methods (anti-acetylated alpha-tubulin) in conjunction with confocal laser scanning microscopy were used to investigate the wiring pattern of the nervous systems of the grafts. In all cases, at least two supraesophageal ganglia were formed and palps, antennae and nuchal organs were innervated by the correct nerves but, in special cases, were innervated vice versa from the other brain. From these results it can be concluded that fusion of a regenerating connective with another connective results in formation of a new brain, irrespective of whether it belongs to the same nerve cord or not.     

Postnatal development of the rat intrinsic cardiac nervous system: a confocal laser scanning microscopy study in whole-mount atria

We used confocal laser scanning microscopy and fluorescent immunohistochemistry to study the developmental pattern and distribution of specific neuronal phenotypes within the intrinsic cardiac nervous system in whole-mount atrial preparations from newborn to 5 week old rats. Individual ganglia and neuronal cell bodies were localized by means of two general neuronal markers: protein gene product 9.5 (PGP) and microtubule-associated protein two (MAP). In rats < or =2 weeks old there were two main subpopulations of intrinsic neurons located in the intraatrial septum and around the origin of the superior vena cava. The more abundant was a population of strongly tyrosine hydroxylase (TH) immunoreactive (IR) neurons (10-40 microm in diameter) most of which were also PGP-IR. The second, less numerous (approximately 60-70% than the TH-IR group) type of neurons exhibited ChAT-IR which colocalized with MAP-IR. Towards the end of the second postnatal week and during the third, the ganglia containing these neurons became more numerous and their localization also included tissues around the origins of the inferior vena cava and the pulmonary veins, as well as both atrial walls close to the AV junction. During the second and third postnatal weeks, when the extrinsic innervation of the adrenergic and cholinergic phenotypes largely increases, the intrinsic innervation also changed greatly, and around the 21st postnatal day it appeared to acquire mature characteristics. The TH-IR neurons changed their characteristics and formed two types of ganglia. The larger ganglia containing large cells (20-40 microm in diameter) expressed TH-IR mostly close to their inner body surface (approximately 80-90% of identified neurons). Most of these neurons also expressed neuropeptide Y (NPY)-IR, specifically around their nuclei. The second type of small strongly TH-IR neurons (approximately 10% of all identified neurons) were contained in smaller groups (20-50 cells) which were usually embedded into much larger ganglia (100-400 cells), containing large (20-50 microm) neurons. Unlike all other intrinsic neurons, these small TH-IR cells did not exhibit any PGP-IR or MAP-IR. The number of ChAT-IR neurons increased at this stage, reaching approximately 90% of the neurons identified by the general neuronal markers. These neurons were surrounded by a rich network of cholinergic varicose nerve fibers, some of which were likely of an extrinsic origin. We have also identified relatively small ganglia expressing immunoreactivity to vasoactive intestinal polypeptide (VIP), and to substance P (SP). The presented data indicate that the phenotypes of intrinsic neurons in the rat heart change greatly during the first month of postnatal development. This may be at least partially related to the development and maturation of functional extrinsic nervous control of the heart.     

New era of optogenetics: from the central to peripheral nervous system

Abstract

Optogenetics has recently gained recognition as a biological technique to control the activity of cells using light stimulation. Many studies have applied optogenetics to cell lines in the central nervous system because it has the potential to elucidate neural circuits, treat neurological diseases and promote nerve regeneration. There have been fewer studies on the application of optogenetics in the peripheral nervous system. This review introduces the basic principles and approaches of optogenetics and summarizes the physiology and mechanism of opsins and how the technology enables bidirectional control of unique cell lines with superior spatial and temporal accuracy. Further, this review explores and discusses the therapeutic potential for the development of optogenetics and its capacity to revolutionize treatment for refractory epilepsy, depression, pain, and other nervous system disorders, with a focus on neural regeneration, especially in the peripheral nervous system. Additionally, this review synthesizes the latest preclinical research on optogenetic stimulation, including studies on non-human primates, summarizes the challenges, and highlights future perspectives. The potential of optogenetic stimulation to optimize therapy for peripheral nerve injuries (PNIs) is also highlighted. Optogenetic technology has already generated exciting, preliminary evidence, supporting its role in applications to several neurological diseases, including PNIs.     

Characterization of theGeosiphon pyriforme symbiosome by affinity techniques: confocal laser scanning microscopy (CLSM) and electron microscopy

Summary Geosiphon pyriforme represents a photoautotrophic endosymbiosis of aGlomus-like fungus with the cyanobacteriumNostoc punctiforme. The fungus forms unicellular bladders of up to 2 mm in length and 0.5 mm in diameter growing on the soil surface and harboring the endosymbioticNostoc filaments. The cyanobacteria are located in a compartment (the symbiosome) bordered by a host membrane. The space between this symbiosome membrane (SM) and theNostoc cell wall is filled with an about 30–40 nm thick layer of amorphous material, which is present also in the regions of the symbiosome where noNostoc filaments are located. At these sites the amorphous material consists of a 20–30 nm thick layer separating the SM. The region between the SM and the cyanobacterium is defined as symbiosome space (SS). Fungal bladders, hyphae and free livingNostoc were analyzed by affinity techniques as well as the material occurring in the SS. FITC-coupled lectins with sugar specificity to -D-mannosyl/-D-glucosyl (Con A), N-acetyl--D-glucosamine oligomers (WGA), -L-fucosyl (UEA-I), -D-galactosyl (RCA-120), -D-galactosyl (BS-I-B₄), N-acetyl--D-galactosamine (HPA), and sialic acid (EBL) residues were tested. WGA binding and calcofluor white staining demonstrated that the bladder wall as well as the SS contain fibrillar chitin. Of the other lectins only Con A clearly labeled the symbiosome. On the contrary, the lectin binding properties of the slime produced by free livingNostoc-colonies indicate the presence of mannose, fucose, GalNAc, sialic acid, and galactose, while chitin or GlucNAc-oligomers could not be detected. The symbiosome was also investigated electron microscopically. WGA-gold binding confirmed the presence of chitin, while a slight PATAg reaction indicated some polysaccharidic molecules within the SS. Our results show that the amorphous material within the SS contains molecules typical of the fungal cell wall and suggest that the SM is related to the fungal plasma membrane. The applied lectins all bind to the hyphal surface, indicating a high molecular complexity. Mannosyl, -galactosyl, and sialic acid residues are strongly exposed at the outer cell wall layer, whereas GlucNAc, GalNAc, and -galactosyl residues seem to be present in smaller amounts. The symbiotic interface established between the fungus andNostoc inGeosiphon shows many similarities to that occurring between fungi and root cells in arbuscular mycorrhizas.Abbreviations AM arbuscular mycorrhiza - BS-I-B₄ Bandeiraea simplicifolia lectin I isolectin B₄ - CLSM confocal laser scanning microscopy - Con A Concanavalin A - EBL elderberry bark lectin I - FITC fluorescein isothiocyanate - HPA Helix pomatia agglutinin - PATAg periodic acid-thiocarbohydrazide-Ag proteinate - SM symbiosome membrane - SS symbiosome space - RCA-120 Ricinus communis agglutinin 120 - UEA-I Ulex europaeus agglutinin I - WGA wheat germ agglutinin Dedicated to Professor Dr. Peter Sitte at the occasion of his 65th birthday     

DNA-fluorescence of mammalian intra-nucleolar chromatin detected by confocal laser scanning microscopy (CLSM)

The complex spatial DNA distribution in the mammalian interphase nucleus was investigated in Feulgen stained thick sections through mouse trophoblast giant nuclei after Lowicryl embedding. DNA-fluorescence was visualized using confocal laser scanning microscopy. Our results show that the spatial arrangement of major interphase chromatin areas can be precisely documented, including the distribution of small intra-nucleolar chromatin zones.     

Reproductive system abnormalities in Schistosoma mansoni adult worms isolated from Nectomys squamipes (Muridae: Sigmodontinae): brightfield and confocal laser scanning microscopy analysis

Schistosoma mansoni adult worms with genital anomalies isolated from Nectomys squamipes (Muridae: Sigmodontinae) were studied by confocal laser scanning microscopy under the reflected mode. One male without testicular lobes (testicular agenesia/anorchism) and two females, one with an atrophied ovary and another with 17 uterine eggs, were identified. The absence of testicular lobes occurred in a worm presenting otherwise normal male adult characteristics: tegument, tubercles and a gynaecophoric canal with spines. In both female specimens the digestive tube showed a vacuolated appearance, and the specimen with supernumerary uterine eggs exhibited a developing miracidium and an egg with a formed shell. The area of the ventral sucker was similar in both specimens however the tegument thickness, ovary and vitelline glands of the specimen with the atrophied ovary were smaller than those of the one with supernumerary eggs. These reported anomalies in the reproductive system call attention to the need to improve our understanding of genetic regulation and the possible role of environmental influences upon trematode development.     

Musculature of Notholca acuminata (Rotifera: Ploima: Brachionidae) revealed by confocal scanning laser microscopy

Abstract. The body-wall and visceral musculature of Notholca acuminata was visualized using phalloidin-linked fluorescent dye under confocal laser scanning microscopy. The body-wall musculature includes dorsal, lateral, and ventral pairs of longitudinally oriented body retractor muscles, two pairs of head retractors, three pairs of incomplete circular muscles, which are modified into dorso-ventral muscles, and a single pair of dorsolateral muscles. The visceral musculature consists of a complex of thick muscles associated with the mastax, as well as several sets of delicate fibers associated with the corona, stomach, gut, and cloaca, including thin longitudinal gut fibers and viscero-cloacal fibers, never before reported in other species of rotifers. The dorsal, lateral, and ventral retractor muscles and the incomplete circular muscles associated with the body wall appear to be apomorphies for the Rotifera. Muscle-revealing staining shows promise for providing additional information on previously unrecognized complexity in rotifer musculature that will be useful in functional morphology and phylogenetic analyses.     

Differential expression of the Tmem132 family genes in the developing mouse nervous system

The family of novel transmembrane proteins (TMEM) 132 have been associated with multiple neurological disorders and cancers in humans, but have hardly been studied in vivo. Here we report the expression patterns of the five Tmem132 genes (a, b, c, d and e) in developing mouse nervous system with RNA in situ hybridization in wholemount embryos and tissue sections. Our results reveal differential and partially overlapping expression of multiple Tmem132 family members in both the central and peripheral nervous system, suggesting potential partial redundancy among them.     

Development of the reproductive system of Echinostoma paraensei in Mesocricetus auratus analyzed by light and confocal scanning laser microscopy

This study was performed to gain insight into the maturation of the reproductive system of Echinostoma paraensei worms grown in an early infection of Mesocricetus auratus. Hamsters were infected with 100 metacercariae and necropsied on days 3, 5, 7, 10 and 14 post infection (dpi). Recovered flukes stained with hydrochloric carmine were preserved as whole mounts and analyzed by light and confocal scanning laser microscopy. The average worm recovery was 43.7 per host. Images of the male and female reproductive systems were taken. The ovary and anterior and posterior testis were evidenced on day 3, while the ootype and cirrus sac were present on day 5. Confocal imaging showed primordium testis and ovary as a cluster of primordial cells from day 3 onward. The testes, ovary, cirrus sac and uterus organs were already present during the first week of life. The two testes were seen as individual structures on 7 dpi while the cirrus sac and vitelline glands were in development. The ovary was connected to the uterus while the ootype was adjacent to it. Both testes were larger than the ovary, showing cells at different stages of development, but with few bundles of functional spermatozoa in 10 day-old worms. On day 14, eggs and spermatozoa were seen in the uterus and seminal vesicle, respectively, while oocytes appeared in the ootype as fertilized eggs. We conclude that the reproductive system of E. paraensei was functional on 14 dpi in the hamsters.     

Anatomical pathways connecting lip sensory structures and central nervous system in hirudinid leeches visualized by carbocyanine dyes and laser scanning confocal microscopy

Chemoreception inHirudo medicinalis is thought to be mediated by ciliated cells grouped in sensory structures, the sensilla, arranged in bands on the animal's dorsal lip (Elliott, 1986; Zipseret al., 1994). Furthermore, chemical and/or thermal stimulation of the dorsal lip in reduced preparations evokes changes in the electrical activity of the cephalic nerves that connect the head with the central nervous system. However, the complete trajectory by which the sensory afferents teach the cerebral ganglia has not been demonstrated anatomically. In this study, we traced these pathways following retrograde and/or anterograde transport of carbocyanine dyes (DiI, DiA and DiD) in the cephalic nerves ofHirudo medicinalis and a closely related species,Macrobdella decora. While information regardingMacrobdella's chemoreception is scarce, the two species show some differences with regard to their chemical preferences. Dyes were applied to the sensillar structures along the dorsal lip, or to the cut ends of individual cephalic nerves in fixed preparations that included the lip and attached nerves with or without the head ganglia. After a two week incubation, specimens were mounted and imaged using a confocal microscope.The results show that the axons of the sensory neurons in the sensilla project through the four pairs of cephalic nerves. The sensillar projections are however more numerous in the dorsal nerves than they are in the ventral ones. In addition, the organization of the sensillar bands, the morphology of the pathways and the sensory structures themselves appear to be identical forHirudo andMacrobdella and therefore the behavioral differences in response to appetitive stimuli cannot be readily explained by differences in morphology.     

The placebo effect and the autonomic nervous system: evidence for an intimate relationship

For many subjectively experienced outcomes, such as pain and depression, rather large placebo effects have been reported. However, there is increasing evidence that placebo interventions also affect end-organ functions regulated by the autonomic nervous system (ANS). After discussing three psychological models for autonomic placebo effects, this article provides an anatomical framework of the autonomic system and then critically reviews the relevant placebo studies in the field, thereby focusing on gastrointestinal, cardiovascular and pulmonary functions. The findings indicate that several autonomic organ functions can indeed be altered by verbal suggestions delivered during placebo and nocebo interventions. In addition, three experimental studies provide evidence for organ-specific effects, in agreement with the current knowledge on the central control of the ANS. It is suggested that the placebo effects on autonomic organ functions are best explained by the model of 'implicit affordance', which assumes that placebo effects are dependent on 'lived experience' rather than on the conscious representation of expected outcomes. Nevertheless, more studies will be needed to further elucidate psychological and neurobiological pathways involved in autonomic placebo effects.     

Improvements for the anatomical characterization of insect neurons in whole mount: the use of cyanine-derived fluorophores and laser scanning confocal microscopy

The optical sectioning capability of the laser scanning confocal microscope was utilized to image dye-filled neurons within whole-mounted insect ganglia. Specific pterothoracic interneurons, in the mothManduca sexta, were retrogradely filled with Neurobiotin and subsequently visualized with a monoclonal anti-biotin conjugated with one of the following fluorophores: fluorescein, and the newly developed cyanines, Cy3.18 (Cy3) and Cy5.18 (Cy5). Overall, the Cy5 fluorophore was best suited for imaging insect neurons within ganglia. This new methodology allowed us to identify and characterize morphologically a collection of descending multisegmental interneurons with large or small diameter somata. A variety of larger molecular weight (10000 daltons) tracers was also used to examine the possibility of nonselective filling of neurons with Neurobiotin, possibly through gap junctions. We also investigated the usefulness of Cy3 and Cy5 as fluorophores for transmitter immunostaining of neurons in whole mount. Neurons immunoreactive for serotonin and the neuropeptides, FMR Famide and SCPb, were imaged in the brain and the pterothoracic ganglion. The central projections of some of these immunoreactive neurons were imaged in their entirety.     

β-chemokine expression and distribution in paraffin-embedded transplant renal biopsy sections: analysis by scanning laser confocal microscopy

 Previous immunohistochemical and in situ hybridisation studies have shown that, in tubulitis associated with acute cellular rejection of human renal allografts, intratubular T cells proliferate and are fully activated in situ. In the immunohistochemical study reported here we have attempted to establish some understanding of the involvement of the β-chemokines RANTES, MCP-1, MIP-1α and MIP-1β in recruiting T cells to the intratubular site. Paraffin-embedded routine biopsy sections were treated for conventional indirect immunofluorescence to detect the selected chemokines. Scanning laser confocal microscopy was used to provide a measure of fluorescence intensity resulting from binding of FITC-labelled secondary antibody. Cells expressing chemokines could be identified and, within the limits of the staining method, it was possible to obtain a semi-quantitative assessment of individual chemokine activity at different points in biopsy sections by constructing a profile of fluorescence intensity. High concentrations of chemokines (especially RANTES, MIP-1β and/or MIP-1α) were localised to the basolateral surface of tubular epithelial cells (TEC). MCP-1 was also consistently present but at a lower level than RANTES except in one case identified as BANFF category 3. There was diffuse distribution of chemokines in the interstitial matrix and low intensity fluorescence outlined some endothelial cells of peritubular venules and interstitial fibroblast-like cells. Our results suggest a mechanism for specific chemotactic recruitment of inflammatory cells by TEC-produced chemokines. Accepted: 22 January 1998