bluuebunny/crossref_metadata_2025 huggingface dataset:
Specialized cilia of the byssus attachment plaque forming region in Mytilus californianus
Authors: Tamarin A. , Lewis P. , Askey J.
Published: February 2005

The distal depression of the ventral pedal groove of Mytilus californianus was investigated by scanning and transmission electron microscopy. This part of the byssus forming system is responsible for the formation of the attachment plaque of the byssus thread.

The longitudinal pedal ducts open into this area and the floor of the distal depression is covered by specialized cilia which terminate as biconcave flattened discs or “paddles.” The disc is formed by a 360° curvature of the axoneme tip within the ciliary membrane. The diameter of the disc is about 1.33 μ while that of the shaft portion is 0.24 μ. There are about 11 cilia per square micron of surface area and the necks of the cilia are separated from each other by a web‐like extension of apical cytoplasm extending from the epithelial cells.

It is proposed that these specialized cilia function as microscopic spatulas for the application of the adhesive plaque material to substrate surfaces. The pattern of surface convection currents seen in vivo tends to support this hypothesis.
A comparative ultrastructural and behavioral study of the antennal sensory sensilla of the parasitoid Cardiochiles nigriceps (hymenoptera:Braconidae)
Authors: Norton William N. , Vinson S. B.
Published: February 2005

Scanning and transmission electron microscopy studies were conducted on the antennal sensory sensilla of the hymenopteran parasitoid, Cardiochiles nigriceps Viereck, of the family Braconidae. Distinct morphological differences were found between the chemoreceptors of the male and female. Curved, non‐fluted, thin‐walled sensilla were found to be very abundant on the male and restricted in location and number on the female. Trichoid, placoid and fluted basiconic sensilla were numerous on the antennal flagella of both sexes. Smooth basiconic sensilla were restricted in number to one per flagellar segment in both sexes. Behavioral data suggest that bent‐tipped, thick‐walled sensilla unique to the female are involved in detecting a chemical(s) emitted from the host, Heliothis virescens (Fab.).
A fine structure study of venom gland cells in globiferous pedicellariae from Stronglocentrotus purpuratus (Stimpson)
Authors: O'Connell Michael G. , Alender Charles B. , Wood Eunice M.
Published: February 2005

Cells in secretory glands of globiferous pedicellariae from Strongylocentrotus purpuratus (Stimpson) were studied with the electron microscope and subjected to preliminary light microscopic, histochemical analysis. Specimens for electron microscopic observation were fixed with chilled 2% glutaraldehyde in sea water postfixed in cold 1.33% osmic acid, and embedded in Araldite 502 epoxy resin Samples for histochemical analysis were fixed in the same manner, and then embedded in n‐butylmethacrylate.

Secretory cells line and fill partially bifurcated, muscular gland sacs located peripherally on each of three jaw elements comprising the pedicellarial head. Cells from venom glands are typically mucoid in appearance, possessing small volumes of basally displaced, vesiculated cytoplasm and an extensive system of vacuoles dominating the apical nine‐tenths of each cell. These vacuoles enclose ground substances of various densities and staining affinities. Despite their extensive vacuolation, gland cells contain numerous cytomembrane complexes indicating metabolic activity just prior to fixation. Deciduous endoplasmic reticulum, Golgi complexes, large vacuoles, and various species of vesicles associated with these membrane systems are found in spatial proximity which indicates an apparent biosynthetic association.

Preliminary histochemical tests on sections embedded in acrylic plastic indicate vacuolar products may consist of protein and nonsulfated acid mucosubstances.

Gland cells are probably holocrine in function, releasing their vacuolar complement upon constriction of the muscular gland sac. There is no evidence indicating delivery of non‐membrane bounded, granular secretion to an acellular lumen within the gland sac.
The auditory bulla in carnivora: An anatomical basis for reappraisal of carnivore evolution
Authors: Hunt Robert M.
Published: February 2005

Basicranial anatomy of mammalian carnivores is significant in the determination of carnivore evolution. One of the least understood yet most often studied features of the basicranium is the auditory bulla, a bony capsule enclosing the middle ear. Although previously believed to be formed by a tympanic bone alone, or by tympanic and entotympanic, it is shown here that the carnivore bulla is formed by three and in some cases four ontogenetic elements: tympanic, rostral entotympanic, caudal entotympanic(s). These elements in Carnivora appear to correspond to bulla elements discovered over 50 years ago by Van der Klaauw in representative species of several other orders of mammals.

Increased auditory sensitivity appears to have been attained in various carnivore lineages by increase in the volume of the middle ear cavity, principally by hypertrophy of the caudal entotympanic, but also by different yet less common anatomical strategies such as invasion of the mastoid bone by the middle ear space. Five basic types of bulla among living Carnivora can be recognized, based largely on the relationship of the caudal entotympanic to the other bulla elements.

Closely associated with the bulla in the auditory region are the median and promontory branches of the internal carotid artery. These branches exhibit a precise relationship to the bulla elements, particularly the rostral entotympanic. The promontory branch is much reduced or completely lacking in all living carnivores. Reduction or loss of the median branch is explained as the result of the development of arterial retia on the anastomotic artery in the orbital region. Reduction of the median branch is particularly characteristic of the aeluroid Carnivora, in which a greater proportion of the cerebral blood supply passes to the brain in the external carotid artery via the anastomotic branch, and is cooled in the orbital region by a countercurrent heat exchange mechanism formed by arterial retia closely associated with venous blood in surrounding sinuses. The arctoid and cynoid Carnivora are characterized by only rudimentary development of retia along the anastomotic artery, and the median branch is much better developed than in the aeluroids. Among arctoids, ursids parallel the aeluroids in the development of a countercurrent mechanism but employ the median branch of the internal carotid rather than the anastomotic branch of the external carotid artery.

Bulla structure and nature of the carotid circulation in the auditory region can be determined from fossil Carnivora as well as for living forms. This study attempts to define basicranial anatomical patterns characteristic of living Carnivora which then can be used to trace the evolution of lineages in the fossil record.
The ultrastructure of Pyrsonympha and its associated microorganisms
Authors: Bloodgood Robert A. , Miller Kenneth R. , Fitzharris Timothy P. , Mcintosh J. Richard
Published: February 2005

The termite gut flagellates are of interest because of their unusual motile organelles, their ability to digest cellulose, and their symbiotic relationship with prokaryotes inhabiting the insect gut. This report provides a detailed ultrastructural description of Pyrsonympha from the hind‐gut of Reticulitermes flavipes.

The motile axostyle is composed of 2,000–4,000 microtubules connected by cross‐bridges. At its anterior end, the axostyle is associated with a “primary row” of microtubules which is associated with a fibrous network. The “primary row” is embedded in a large mass of amorphous, electron‐dense material occupying the furthest anterior end of the cell. The basal bodies of the eight flagella are also embedded in this presumptive microtubule‐organizing center. The flagella are associated with the cell surface throughout their length. Isolation and reactivation of the axostyle has demonstrated that although ATP dependent motility is inherent in the structure of the axostyle, its proper control may be mediated by the attachment of the axostyle to structures at the anterior end of the cell.

Pyrsonympha lacks morphologically distinguishable mitochondria and Golgi complexes. The cell surface is covered by unique, previously underscribed, tubular specializations. Symbiotic microorganisms are observed associated with the cell surface and within the cytoplasm.

Wood particles are taken up from the gut fluid by large phagocytic vacuoles formed at the posterior end of the cell. Even during the process of breakdown, the wood is always enclosed within the membrane of the phagocytic vacuole.

The Pyrsonympha from Reticulitermes flavipes are not attached to the lining of the hind‐gut and do not contain an attachment organelle, unlike the Pyrsonympha from other species of Reticulitermes.
The male genital system in two species of mysid crustacea
Authors: Kasaoka Laurel D.
Published: February 2005

The male genital systems of two mysids, Archaeomysis grebnitzkii (subfamily Gastrosaccinae) and Neomysis awatschensis (subfamily Mysinae) are described. The testes of both species include a pair of central cords (spermatogonial cells), two sets of lateral sacs, and a set of dorsal‐lateral spermatidic pouches in which spermiogenesis takes place. Mature sperm exit dorsally from the pouches into a common U‐shaped seminal vesicle, the arms of which extend posteriorly as the right and left vasa deferentia.

The emphasis of this study was on the follicle cell‐spermatid relationship. Spermatids retain their own cell membranes as do the follicle cells. A bundle of sperm tails extends toward the follicle cell nucleus making several revolutions about the nucleus. Masses of rodlets occupy this tract with the spermatid tails. The tail consists of an outer cylinder with banding in a periodicity similar to collagen protein, and an inner cavity filled with a structureless, dark‐staining material. Heads of the spermatozoa differ considerably between the two species. The elongate, reflexed head of Neomysis with its central filament joins the tail at an acute angle. The short cylindrical head of Archaeomysis with its anterior hood‐like extension joins the tail directly. The distinctiveness of the sperm types might prove useful for taxonomic purposes. As noted by previous investigators, the number of spermatids per follicle cell shows specificity: Neomysis awatschensis has around 16 spermatids per follicle cell, Archaeomysis grebnitzkii about 100.
Evaluation of some morphological characteristics of spores of two species of microsporida by scanning electron microscope and freeze‐etching techniques
Authors: Liu T. P. , Liu H. J.
Published: February 2005

Scanning electron microscopy revealed spores of Nosema apis and Thelohania fibrata to be egg‐shaped, but only the mature spore of T. fibrata was shown to possess a horseshoe‐like concavity at the posterior pole. Freezeetched preparations indicated that this concavity was due to a thin area of the spore coat. Freeze‐etching studies also show spores of N. apis do possess an umbrella‐shaped polaroplast, and a polar filament which is arranged in a double layer with over 30 coils. The spore of T. fibrata contains a pear‐shaped arrangement of the polaroplast membrane, and a polar filament arranged in a single layer of 22 coils.
Special cutaneous receptor organs of fish. VII. Ampullary organs of mormyrids
Authors: Szamier R. Bruce , Bennett Michael V. L.
Published: February 2005

Ampullary receptor organs of African mormyrids consist of a cavity beneath the epidermis. The wall of the cavity contains embedded receptor cells and two types of supporting cells. A canal extends from the cavity to an opening at the surface. The lumen of the canal and the ampulla are filled with a jelly‐like material and dense cylinders apparently secreted by two types of supporting cells. Flattened cells of the canal wall are joined by occluding junctions. Synapses between receptor cells and the afferent nerve fiber are characterized by a presynaptic dense body, but presynaptic vesicles were not observed. Degenerating receptor cells are occasionally seen among normal receptor cells in the base of the organ.
Lymphoid organ development in Xenopus thymectomized at eight days of age
Authors: Horton John D. , Manning Margaret J.
Published: February 2005

This paper examines the effect of early thymectomy on the subsequent development of lymphoid tissues in the toad, Xenopus laevis. At the time of thymic removal (8 days post‐fertilization) all the lymphoid organ anlagen are at a rudimentary state of differentiation and contain few, if any, small lymphocytes. Despite the absence of any thymic tissue all thymectomized animals grew normally.

Thymectomized larvae developed relatively normal lymphoid organs. However, lymphoid depletion was apparent in the splenic red pulp and in the pharyngeal ventral cavity bodies. Examination of the lymphoid organs of post‐metamorphic Xenopus revealed reduction in spleen size following thymectomy. Lymphoid depletion was evident in the splenic red pulp of many thymectomized toadlets and reduction in proportion of white to red pulp was also noted in a few of these animals. Absence of the thymus had no apparent effect on the histology of the other lymphoid organs examined.
The occurrence of muscle spindles in extraocular muscles of various vertebrates
Authors: Maier Alfred , Desantis Mark , Eldred Earl
Published: February 2005

Extraocular muscles from representative species of vertebrate groups ranging from amphibians to the higher mammals were examined in serial histological sections for the presence of muscle spindles. These observations and data from the literature indicate that extraocular muscles of the pig, calf, sheep and other even‐toed ungulates are richly supplied with well‐defined spindles having a generous complement of intrafusal fibers distinguishable as nuclear bag and chain fibers. Spindles in human eye muscles are also numerous. In macaque and chimpanzee muscles a few poorly developed spindles were present in some, but not all, muscles. No encapsulated receptors were found in 20 other mammalian and submammalian species examined in this study. When present, spindles tended to be located in the zone of small muscle fibers found along the orbital surface of the muscle. Rectus and oblique muscles in all species had such a zone, so that its existence did not determine whether spindles would occur.
Postembryonic development of the cervicothoracic muscles of Euborellia annulipes (Lucas) (Dermaptera: Labiduridae)
Authors: Bharadwaj R. K. , Chadwick L. E.
Published: February 2005

The cervicothoracic muscles of nymphal and adult Euborellia annulipes (Lucas) are described, the former for the first time. In the adult, eight new muscles are identified, while the nymphs possess a further seven muscles that disappear at maturation or before. Otherwise the same muscles occur in nymphs as in adults, though some nymphal muscles are less clearly separated from one another than their adult homologs. The attachment sites of certain muscles show a number of slight differences between nymphs and adults. The work emphasizes the necessity of taking the immature musculature into account in assessing the muscular pattern represented in an insect order.
Embryology and cytodifferentiation of the pituitary gland in the lizard Anoiis carolinensis
Authors: Pearson Anita K. , Licht Paul
Published: February 2005

Anolis embryos have limb buds at the time eggs are laid and require about 39 days to complete development at 28°C. Rathke's pouch is present at five days, and the subdivisions of the adenohypophysis are differentiated by ten days after oviposition. The cells of the rostral half of the pars distalis (PD) are derived from the anterior face of Rathke's pouch; cells of the caudal half from the posterior face. Lateral lobe cells differentiate on the lateral margins of the developing caudal PD, and knob‐like outgrowths of this tissue attach to the walls of the diencephalon to form the pars tuberalis (PT). Subsequently, the cells of the PT lose their connection with the PD and become a pair of flattened oblong plaques. They reach maximal size in midincubation, and are gradually invaded by nervous elements and incorporated into the walls of the hypothalamus. Electron micrographs demonstrate that the embryonic PT is secretory.

Ultrastructurally the pars intermedia (PI) and PD are composed of parenchymous secretory cells in a framework of stellate cells. Stellate cells surround the lumen of Rathke's pouch and are connected laterally by complex junctions that exclude the secretory cells from the luminal surface. They extend in sheet‐like processes among the secretory cells to the outer margin of the gland where they form a partial sheath within the basal lamina around the secretory tissue. As development proceeds, the lumen becomes subdivided and the resulting reduced lumina are recognizable as the forerunners of the follicles of the adult adenohypophysis.

The cells of the PI are differentiated into secretory or stellate cells halfway through incubation. At this time only half of the cells of the PD can be so classified. Four of the five granulated cell types described in the adult are recognizable by mid‐incubation; the fifth cell type (prolactin cell) becomes distinguishable within ten days thereafter, and at hatching appears to be actively synthesizing secretory products.
Morphology and function of the dorsal sound producing scales in the tail of Teratoscincus scincus (Reptilia: Gekkonidae)
Authors: Hiller Uwe
Published: February 2005

The tail of Teratoscincus scincus has dorsal scales that have tubercles on their dorsal and ventral surfaces. Sounds are produced when these rub past each other as the excited animal moves its tail. The relative movement of scales is intensified by caudal torsion. The frequencies of the sounds cover a range from 9 to 25 kops and thus, differ from those produced during vocalizations.
Surface structures of the antennular flagella of the hermit crab Pagurus alaskensis (Benedict): A light and scanning electron microscopy study
Authors: Snow Peter J.
Published: February 2005

The surface structures of the antennular flagella of Pagurus alaskensis are described in detail. Attention is directed towards the surface morphology of two types of possible sensilla: (1) exoskeletal pores (1.0–3.0 μm in diameter); (2) setae of various kinds. In addition, small (0.1–0.2 μm) pits occur in the exoskeleton which are not considered to be sensory in function. The exoskeletal pores are found at fairly specific locations on both the inner and outer flagella, particularly on the short segments of the outer flagella. Neither the inner nor the outer flagella are bilaterally symmetrical with respect to their setal armature. On the outer flagellum six groups of setae may be distinguished: lateralmesial; dorsal; ventral; accessory; aesthetasc; setae of the distal segment. On the inner flagellum setae of the mesial and lateral rows form distinctive groups. The morphology, orientation and locations of all the flagellar setae are defined and where possible the numbers of the various morphological types within the specific setal groups are given. It is noteworthy that many setal types have obvious apical pores and yet no pores could be found in the chemoreceptive aesthetasc setae. The functions of the various setae are discussed in relation to their topographical position and to existing electrophysiological and behavioral data. Some suggestions are made about future experiments to demonstrate the central connections of specific sensilla or groups of sensilla and to show their significance in the whole animal.
Studies on the control of nucleolar number in mammalian cells: Effects of thyroid hormones, sex and strain specificity in mouse hepatocytes
Authors: Tishler Peter V. , Bentman Adrienne
Published: February 2005

The mean number (± S. D.) of nucleoli per hepatic cell was determined for inbred mice of the BALB/c and C57BL/6J strains, using azure B bromide. Because thyroid hormones have been reported to increase nucleolar number in cultured human cells, certain of the males received parenteral triiodothyronine (T3). Hormone effect was demonstrated by a two‐fold increase in hepatic mitochondrial α‐glycerophosphate dehydrogenase activity. Results included the following: (1) In the BALB/c strain, the nucleolar number of the T3 treated males (5.0 ± 2.4) was slightly but significantly higher (p < 0.001) than that of the controls (4.8 ± 2.3). For the C57BL/6J strain, however, the nucleolar number of the treated males (4.0 ± 1.7) was significantly lower than the controls (4.2 ± 1.8; p < 0.001). (2) The difference in nucleolar numbers of untreated males of both inbred strains was highly significant (p < 0.001). (3) The nucleolar number in BALB/c female cells (4.1 ± 1.8) was significantly lower than that of male BALB/c cells (p ≪ 0.001).
Internal and external morphology of the deutonymph of Caloglyphus boharti (Arachnida: Acari)
Authors: Woodfing J. P. , Carter S. C.
Published: February 2005

A band of flexible cuticle encircles the deutonymph, separating the dorsal and ventral plates. The coxae are large, flat and fused with one another to form most of the ventor. Individual coxal margins are redefined as sternites, epimerites or simply apodemes according to which margins fuse with which others. A given area of cuticle may have patches of dark or light cuticle not corresponding to particular structures or cuticular contours; this is a source of confusion to taxonomists.

Each leg has a dicondylic coxal‐trochantal (adduction‐abduction) and trochantal‐femoral (promotion‐remotion) joint with opposing muscles. The three more distal monocondylic joints (flexion‐extension) have only flexor muscles; extension is by increased haemolymph pressure.

The five apodemes of the sucker plate provide rigidity; the four suckers attach by a flexible cuticular ring to a solid flange or socket in the sucker plate. The sucker muscles attach to the center of each sucker. The flat, external face of the sucker plate apodemes may complement sucker action by adhesion. Coxal discs and sucker plate discs are identical, contain birefringent cuticular elements, and are considered modified setae.

Functional mouthparts and a pharynx are lacking, but a cheliceral anlage is present. The esophagus, midgut and caecae, and malpighian tubules are lumenless and the cells small. The hindgut has a lumen, larger cells and opens externally via the anus. Whereas the digestive tract is regressed, the reproductive system is yet incompletely developed. In older deutonymphs anlagen of ducts, accessory glands and gonads are discernible. The nature of the haemocoel and peritoneum remains nuclear.

The central nerve mass is conspicuously large for the size of the deutonymph. The supraesophageal ganglion gives rise to the cheliceral nerves; all other nerves arise from the subesophageal ganglion. Most major nerves were traced to the effector organs.

The muscles are divided into leg, dorso‐ventral (derived from coxal muscles), dorsal, sucker, and anogenital muscles. The trochantal adductor muscles originate on an endosternite, which is supported by muscles running to the dorsal hysterosoma. The dorso‐ventral and propodosomal retractor muscles affect haemolymph pressure. The massive sucker retractor muscles are unique to this instar. Anogenital muscles are not well developed.
Distribution patterns of rabbit embryos during preimplantation stage
Authors: Tsutsumi Yoshio , Hafez E. S. E.
Published: February 2005

The pattern of transport and distribution of rabbit embryos in the oviduct and uterus was studied 15 to 168 hours post coitum (p. c.). The reproductive tract was frozen in liquid nitrogen, thawed, and cleared in benzyl‐benzoate solution using Orsini's technique. The location of the eggs and the ampullary‐isthmic junction were identified using transmitted light from a dissecting microscope. Accumulation of the eggs in the oviduct occured in two phases. In the first phase the eggs were retained above the ampullaryisthmic junction, 3–12 hours after ovulation. In the second phase, the eggs were retained 36–60 hours after ovulation, above the uterotubal junction (at a distance approximately 12 % of the oviductal length). The rate of transport of individual eggs in the oviduct, and the time of the entry of eggs into the uterus were variable. Au 78 hours p. c. most blastocysts occupied the proximal half of the uterine horn, although some appeared very close to the internal os of the cervix. Spacing of blastocysts in the uterus, 114 to 120 hours p. c., involved movement of blastocysts away from the cervix. Unfertilized eggs remained in the uterus, along with developing blastocysts 168 hours p. c. Few eggs were retained in the oviduct at 108 and 115 hours p. c.
Electron microscopic study of the open circulatory system of the shrimp, Caridina japonica. I. Gill capillaries
Authors: Nakao Taisuke
Published: February 2005

The ultrastructure of the phyllobranchiate type gill of the shrimp, Caridina japonica, was studied. The most characteristic feature of the open circulatory system of Cardina is the vascular lumen of the gill capillaries which is considered to be the interstitial space. The following observations substantiate this view: (1) a thin fibrous layer forms the innermost structure of the walls of gill capillaries and is in direct contact with the blood stream; (2) filaments in the fibrous layer are assumed to correspond to the reticular fibers in the interstitial space of the alveolar wall of mammals; (3) the absence of the endothelium as well as the endothelial basal lamina which are the essential structural components of the closed circulatory system in vertebrates. The gill epithelium contains intermediate, septate and tight junctions. The first two form a junctional complex near the apical cell border and may function as a permeability barrier by occluding the intercellular space as well as functioning in electrical coupling and cellular adhesion. The tight junction is spot‐like and may serve no role in the function of the permeability barrier.
Scanning electron microscope study of the splenic red pulp in relation to the sequestration of immature and abnormal red cells
Authors: Song S. H. , Groom A. C.
Published: February 2005

Spleens from normal, healthy cats, dogs and rabbits were perfused with Ringer solution until only a few red cells remained. After fixation of the intact organ, small pieces of tissue were dried by a camphene method and examined under the scanning electron microscope. In all three species the red cells remaining in the spleen were either reticulocytes, spiculated cells, or cells of tear‐drop shape and they were found adhering to macrophages and reticulum cells throughout the red pulp. Elongated masses were found on the sinusal surface of fenestrated endothelium (only in dog and rabbit); some of these appeared to be cells of tear‐drop shape emerging from the cords into the sinus. This may perhaps denote a pitting process, as suggested by others, but it cannot be a unique function of fenestrated endothelium for red cells of similar shape were found elsewhere in the pulp. In all three species the network of reticulum fibres presents a very large contact surface area for blood cells and it seems likely that increased cell stickiness, rather than decreased deformability, leads to the trapping of immature red cells in the spleen.
Survival of skin allografts following embryonic limb bud transplants in the turtle, Chelydra serpentina
Authors: Yntema C. L.
Published: February 2005

Allografts of skin were observed in Chelydra serpentina. The response to these grafts was modified by a previous transplantation of a limb bud at an early embryonic stage. When the same donor was used for all transplants, the first skin graft was accepted by the host. A second skin graft, however, was rejected at about the rate of a simple first set allograft of skin. The animals were conditioned by the embryonic limb graft; this embryonic graft can be undergoing rejection at the same time a first set skin graft from the same donor was being accepted. The tolerance induced by the embryonic graft was sepcific for its donor.
Extracerebral caphalic neuroendocine complex of the blattids, Periplaneta americana (L.) and Neostylopyga rhombifolia (Stoll): An in situ study
Authors: Adiyodi K. G.
Published: February 2005

A cardiaca‐allatal commissural plexus (CACP) lies between and partly overlapping the postcommissural lobes of the corpora cardiaca (CC), the nervi corpori allati I (NCA I) and the corpora allata (CA). CACP, which is often continuous posteriorly with a complicated postallatal plexus (PAP), comprises a variable number of connectives with neurosecretory processes linking the cardiaca‐commissural organ or dorsal cardiac commissure (containig tritocerebral fibres) to the NCA I. the allatal commissure and the CA. Neurosecretory processes are exchanged between the two halves of the cephalic neuroendocrine complex (CNC) both intracerebrally at different locales, possibly to ensure functional synchrony of CNC components.

NCA I and CACP are drawn out with their stroma to varying extents over the CA. Histophysiological evidence suggests that part of the stainable secretion stored in, and or in axonal transit through CA may be released through CA surface; NCA I, the nervi cardiostomatogastrici, CACP, perhaps also NCA II may function as neurohaemal areas. A “directed” neurosecretory pathway could be distinguished from PAP to the foregut and the fat body. The degree of spatial intimacy detected between neurosecretory and stomatogastric components of CNC suggests that the two systems may function in an integrated fashion. The recurrent‐oesophageal nerve complex serves not only for a direct transport of neurosecretion, but also as one of the sites of its release.
Microspectrophotometric estimates of non‐histone proteins in cell nuclei displaying differing degrees of chromatin condensation
Authors: Cowden Ronald R. , Curtis Sherill K.
Published: February 2005

Nuclei isolated from mouse thymus, kidney, and liver were fixed in ethanol‐acetic acetic acid; treated with dilute acid to extract histones; stained by three protein end‐group procedures; and measured by scanning, integrating microspectrophotometry. Measurements were also made of nuclei isolated from the same organs and stained by the Feulgen procedure for DNA. Protein end‐group procedures included pH 2.8 Biebrich scarlet (for basic groups), mercury orange (for sulfhydryl groups), and mercury orange after thioglycolate reduction (for the sum of sulfhydryl and disulfide groups). With the exception of the comparison between Feulgen‐stained 2C liver and kidney nuclei, the integrated extinction values obtained for nuclei of a given organ differed significantly from the measurements of nuclei from other organs, regardless of the staining procedure. Furthermore, the integrated extinction values for 2C nuclei were highest in larger, more vesicular nuclei (from liver and kidney) and lowest in condensed thymocyte nuclei, except in the case of measurements of the disulfide content of the nuclei. In this instance, the values of integrated extinction were highest in condensed thymocyte nuclei, intermediate in kidney nuclei, and lowest in 2C liver nuclei. When 2C, 4C, and 8C liver nuclei were compared, the integrated extinction values of 4C nuclei were found to be approximately twice those of 2C nuclei and half those of 8C nuclei. Exceptions included 8C nuclei whose disulfide and Feulgen values were, respectively, higher and lower than expected. The greater disulfide values and reduced Feulgen values obtained in thymocyte and 8C liver nuclei might be related to a greater degree of chrmoatin condensation in these nuclei, and, therefore, to a reduction or selective restriction of their RNA transcriptional capacities.
The integument of the paddlefish, Polyodon spathula
Authors: Weisel George F.
Published: February 2005

The integument of the paddlefish (Polyodon spathula) is unusual as a relatively small amount of mucus is produced by epithelial cells that are not modified into regular mucous gland cells. A thick compact epidermis and dermis compensate for the slight amount of mucus secreted.

Paddlefish have a variety of scales formed of concentric bony lamellae containing osteocytes. There are five kinds of scales: dorsal and ventral fulcra on the caudal fin, rhomboidal scales on the caudal lobe, horny denticles over the pectoral girdle, calcareous denticles on the trunk, and anchor‐shaped plates on the rostrum. Except for the fulcra, the scales are undoubtedly vestigial.

The numerous surface pits on the rostrum, head, operculum, and throat are epithelial invaginations which are not connected to lateral line canals. No nerves lead to the pits. The spherical to cuboidal and often ciliated cells at the base of the pits are considered to be aplasic cells of unformed neuromasts.
An ultrastructural study of byssus stem formation in Mytilus californianus
Authors: Tamarin Arnold
Published: February 2005

In Mytilus californianus, root lamellae of the byssus stem are formed by two morphologically distinct exocrine cell types. Type 1 cells contain large ellipsoid granules which are ultrastructurally identical to those of the collagen gland associated with byssus thread formation: these granules are secreted only at the base of the stem generator. Type 2 cells contain small cylindroid granules which are secreted only from the lateral surfaces of generator septa. The resultant matrix is biphasic because the two secretions are incompletely mixed. Lamellar sheets of matrix are propelled outward by the action of cilia and are molded into a cylinder at the neck region of the stem. However, the stem retains a lamellar pattern.

Byssus threads are attached to the stem by flattened rings formed from thread material which is secreted into the cervical crevice surrounding the neck.

The microanatomy of the stem forming region is described and a new term, “stem generator,” is proposed for this organ.
Slit sense organs on the scorpion leg (Androctonus australis L., Buthidae)
Authors: Barth Friedrich G. , Wadepuhl Martin
Published: February 2005

As in other arthropods the exoskeleton of arachnids is subjected to loads generated by external stimuli and behavioral activities. Far from being mere by‐products of various activities such loads act as signals for mechanoreceptors capable of detecting minute displacements caused by them in the cuticle. In arachnids the slit sense organs serve in this capacity.

Spiders have the most elaborate system of slit sense organs. Our previous studies clearly pointed to a functional significance of their specific location and orientation, as well as degree and type of aggregation (isolated, grouped, compound or lyriform) on respective body parts.

The present study extends our work to the slit sense organs of scorpions. It gives a detailed account of the topography of the organs on the walking legs. In general slits are less orderly arranged on the legs of scorpions than on those of spiders. In the scorpion they never aggregate to form lyriform organs. Instead there are groups at comparable locations forming much more irregular, but still specific patterns. Isolated slits are more numerous on the scorpion leg, but are also less regularly distrubuted there. A common feature of the majority of slits on both the spider and the scorpion leg is their position on the lateral surfaces and their orientation roughly parallel to the long axis of the leg.
The suprarenal glands of a prosimian primate, the lesser bushbaby (Galago senegalensis)
Authors: Carmichael Stephen W. , Haines Duane E. , Pinkstaff Carlin A.
Published: February 2005

The gross relationships and light microscopic anatomy of the suprarenal gland of a prosimian primate, Galago senegalensis, is described. The left gland is located medial to the pole of the left kidney in a fascial compartment of its own. The right suprarenal is located medial to the pole of the right kidney in intimate apposition to the liver and inferior vena cava. The capsule of the right gland blends with the capsule of the right lobe of the liver and is also contiguous with the adventitia of the inferior vena cava.

The histologic appearance of the gland is similar to that of other primate genera. The zona glomerulosa is poorly developed; the zona fasciculata is composed of cell cords and is relatively well developed and the zona reticularis shows no unusual characteristics. The organization of the lipid content of the various cortical zones show a considerably different pattern than previously reported. The zona glomerulosa contains numerous large lipid droplets. In contrast to the bi‐laminar pattern of lipid deposition seen in other primates, the Galago shows three distinct layers of lipid droplets in the zona fasciculata. The zona reticularis has a moderate population of lipid droplets essentially similar to that reported in most other forms. The medulla, except for a sparse number of centrally displaced zona reticularis cells, is completely devoid of lipid deposits. The junction of the zona reticularis and medulla is distinct, although a connective tissue capsule is not present.
A fluorescence microscopic study of the distribution of monoamines in the hypothalamus of the cat
Authors: Poitras Daniel , Parent Andre
Published: February 2005

Three distinct groups of monoamine (MA)‐containing nerve cell bodies have been visualized in the hypothalamus and preoptic area of the cat by means of the Falck‐Hillarp fluorescence histochemical technique. First, numerous small‐sized catecholamine (CA) type neurons were disclosed within the ventral half of the periventricular area in the supraoptic and middle hypothalamic regions. The round to oval neurons of this medio‐ventral group were more especially abundant around the base of the third ventricle, within the arcuate and supraopticus diffusus nuclei. Numerous medium‐sized CA perikarya identified as the dorsal group, were also mapped out in the dorsal and posterior hypothalamic areas. Finally, a small population of both CA and serotonin (5‐hydroxytryptamine, 5‐HT)‐containing neurons was disclosed within the lateral area of the middle and mammillary hypothalamic regions. These multipolar or elongated neurons which compose the lateral group were lying either along the ventrolateral surface of the hypothalamus or around the ventrolateral aspect of the fornix. In addition to these three MA cell groups, a few cells displaying a fluorescence of the CA type were also visualized in the so‐called “dorsal chiasmatic nucleus” after α‐methyl‐dopa treatment. High density of CA axon terminals were found, on the other hand, in the external layer of the median eminence, in the dorsomedial, paraventricular, supraoptic and suprachiasmatic nuclei, and also within nucleus interstitialis of stria terminalis. In the present study, however, it was not possible to identify with certainty any concentration of 5‐HT axon terminals in the cat hypothalamus. Therefore, except for the lateral cell group which could be peculiar to the cat, the topographical distribution of MA nerve cell bodies and axon terminals in the hypothalamus of the cat appears similar to the morphological organization of the MA neuronal elements in the hypothalamus of the rat.
Cytological examination of reduction bodies of Corvomeyenia carolinensis harrison (Porifera: Spongillidae)
Authors: Harrison Frederick W. , Dunkelberger Dana , Watabe Norimitsu
Published: February 2005

Freshwater sponges, Corvomeyenia carolinensis Harrison, were placed into tap water to induce degenerative reduction body formation. Reduction bodies were examined using light and electron microscopy in order to define their histochemical and ultrastructural characteristics. The reduction body of freshwater sponges is an extremely simple developmental system consisting primarily of an archeocyte reserve delimited by a simple squamous pinacoderm. The freshwater sponge reduction body displays many similarities to overwintering phases of marine sponges. The system presents an unusually straightforward vehicle for investigations of degeneration and regeneration as processes in developmental biology and may represent a reasonable vehicle in which to examine the process of the genesis of lysosomes.
External morphology of antennae and their sense organs in the roach Gromphadorhina brunneri (Blattoidea: Dictyoptera)
Authors: Hintze‐Podufal Ch. , Otto B.
Published: February 2005

The antennae and their sense organs in nymphs and adult roaches of Gromphadorhina brunneri, were investigated and described. The number of segments and sensillae of the nymphal antennae depend on the developmental stage. Sexual dimorphism is pronounced. Males have longer antennae than females as well as an abundance of especially long sensory hairs (long wavy hairs), which are probably responsible for the perception of female sex pheromones. They also have more thin‐walled sensory hairs, for instance, sensilla trichodea. On a morphological basis the sensillae of Gromphadorhina brunneri, were named and classified. Long wavy hairs and large sensory hairs appear to be present also in a related species, G. portentosa, but are lacking in others. Their distribution on the antennae varies greatly from that in G. portentosa but their structure varies only slightly. These two types of sense organs are considered to be specialized forms of sensilla chaetica. They are contact chemoreceptors, as are two other types of sensilla chaetica. Furthermore, thin‐walled chemoreceptors are present, such as sensilla trichodea, sensilla basiconica, sensilla coeloconica and a typical mechanoreceptor, the sensillum campaniformium.
Fine structure of the intersegmental membrane glands of the sixth abdominal sternum of female Nomia melanderi (Hymenoptera, Apoidea)
Authors: Youssef Nabil N.
Published: February 2005

The fine structure of the intersegmental glands of the sixth abdominal sternum in 1‐week old females of Nomia melanderi is presented. The plasma membrane of the secretory cell is unfolded in many places and is covered by a basement membrane. The microvillous surface is invaginated to form a rather long sinuous cavity. The endoplasm is almost entirely filled by secretory granules. Many secretory granules are located close to the inner surface of the invaginated plasma membrane. The invagination contains a porous ductule, apparently of cuticulin origin, that is connected directly with the inner layer of the transport duct of the duct‐forming cell. This type of arrangement allows the direct flow of the secretory substance to the outside in a continuous way. The cylindrical duct‐forming cell, besides having typical cell organelles, contains a cuticular transport duct. This duct is composed of a thin cuticulin layer surrounded by a rather thick epicuticular one. The results suggest that the secretory cell has two secretory cycles. The first occurs while the gland is differentiating (at the pupal stage) and is involved in secretion of the cuticulin that forms the porous ductule. The second cycle, which starts by the beginning of nesting, is involved in the secretion of a substance that is carried to the outside via the transport duct of the duct‐forming cell.
Regeneration of digits and forelimbs in the Kenyan reed frog Hyperolius viridiflavus ferniquei
Authors: Richards Christina M. , Carlson Bruce M. , Rogers Sherry L.
Published: February 2005

Newly metamorphosed individuals of the Kenyan reed frog, Hyperolius viridiflavus ferniquei, are able completely to regenerate amputated digits, including the morphologically complex digital pad. The sequence of morphological events is very similar to that seen in the typical epimorphic regeneration of amphibian extremities. Amputated forearms typically produce hypomorphic spike regenerates. Despite the lack of underlying hand and digital structures, an apical “digital” pad commonly differentiates.
The suspensorium of Ctenopoma acutirostre: A comparative functional analysis with Anabas testudineus
Authors: Dutta Hiran Moyee
Published: February 2005

The functional and structural aspects of the suspensorium of Ctenopoma acutirostre have been correlated with those of Anabas testudineus. The different parts of the suspensorium are described, as are the muscles that are functionally connected with the suspensorium. Functions were analyzed by observations on living specimens, and by measurements recorded from the movie films. The role played by various bones and muscles to carry out the functions (the respiration, the gulping, and the feeding) has been explained. The different bones and muscles have been considered as functional units which often are connected to form couplings. During the respiration in Ctenopoma the depression of the lower jaw is conducted by the levator operculiopercular apparatus‐mandible coupling. The presence of this coupling is indicated by the presence of dorso‐ventral movement of the operculum. A remarkable ventro‐dorsal and antero‐caudal movement in the urhyal during feeding shows in Ctenopoma the presence of the sternohyoideus‐hyoid apparatus‐interopercular‐mandible coupling, which depresses the lower jaw. In Ctenopoma, the suspensorium takes part in respiration, gulping, and feeding, whereas in Anabas it is only involved in gulping and feeding. To carry out its functions, the suspensorium implies three articulations: palatocranial, craniohyomandibular, and quadratomandibular with the cranium and the lower jaw, respectively. Finally, the suspensorium has been analyzed as a part of the architectonic structure of the entire head by using a diagrammatic model (fig. 13) based on mutual influence, integration, and couplings.
Epidermal downgrowths in regenerating rabbit ear holes
Authors: Goss Richard J. , Grimes L. Nichols
Published: February 2005

Rabbits are unique among mammals in that their ears can regenerate tissues from the margins of full thickness holes which grow in and completely fill the opening in about two months. The circular blastema that forms around the edges of the hole differentiates a new sheet of cartilage as it regenerates in a centripetal direction. Similar holes in other mammals fail to regenerate and form scar tissue instead of a blastema. Histological studies of the healing around the edges of rabbit ear holes reveal that during the second week, when the epidermis is completing its migration across the wound from the opposite sides of the ear, conspicuous tongues of epidermal cells grow down into the underlying tissues at the edges of the wound. These epidermal downgrowths are situated between the original intact dermis of the skin and the more central tissues which give rise to the blastema. Such downgrowths are of a transient nature, and are no longer found once the blastema rounds up toward the end of the second week. Since they are not found in the healing of similar wounds in rabbit ears prevented from regenerating by prior removal of their cartilaginous sheets, nor in the naturally nonregenerating ears of sheep and dogs, it is considered that these downgrowths of healing epidermis may play a role in the unusual regenerative response of ear tissues in the rabbit.
An ultrastructural study of adhesive junctions in reaggregates of unincubated chick embryos
Authors: Macarak Edward J.
Published: February 2005

Cell suspensions obtained by the dissociation of unincubated chick embryo blastoderms were allowed to reaggregate on a gyratory shaker for 24‐48 hours. The reaggregates which form during this period consist of an inner phase of tightly packed cohesive cells surrounded by an external phase of loosely packed cells. This sorted out arrangement achieves its definitive form between 24 and 48 hours of rotation culture. It was determined that the external phase consists of primitive ectoderm and that the internal phase consists of primitive endoderm. Both 24‐ and 48‐hour reaggregates were examined in the electron microscope and observations were directed to areas of close membrane apposition between cells. In 48‐hour reaggregates, primitive ectoderm cells were joined by predominantly unspecialized junctions while primitive endoderm cells were joined by many specialized junctions (desmosomes). The formation of desmosomes in reaggregates of dissociated unincubated chick embryo cells was correlated with the sorting out process.