The suctorial organ of the Solifugae (Arachnida,Solifugae)

The ability of members of the arachnid order Solifugae to climb smooth, vertical surfaces and the organs involved in this behavior are investigated. Macroscopic, microscopic, and scanning electron microscopic observations are made of a palpal organ called the suctorial organ. Observations of the behavior but not the microstructure have been made in the past. Histological examination illustrates the internal gross anatomy of this structure and scanning electron microscopy demonstrates the fine structure in adults of four genera: Eremobates (Eremobatidae), Eremochelis (Eremobatidae), Eremorhax (Eremobatidae), Ammotrechula (Ammotrechidae), as well as an unidentified late stage immature and third stage instar. The suctorial organ is most likely primarily used for prey capture in the wild.     

Brain – Endocast Relationship in the Australian Lungfish,Neoceratodus forsteri,Elucidated from Tomographic Data (Sarcopterygii: Dipnoi)

Although the brains of the three extant lungfish genera have been previously described, the spatial relationship between the brain and the neurocranium has never before been fully described nor quantified. Through the application of virtual microtomography (μCT) and 3D rendering software, we describe aspects of the gross anatomy of the brain and labyrinth region in the Australian lungfish, Neoceratodus forsteri and compare this to previous accounts. Unexpected characters in this specimen include short olfactory peduncles connecting the olfactory bulbs to the telencephalon, and an oblong telencephalon. Furthermore, we illustrate the endocast (the mould of the internal space of the neurocranial cavity) of Neoceratodus, also describing and quantifying the brain-endocast relationship in a lungfish for the first time. Overall, the brain of the Australian lungfish closely matches the size and shape of the endocast cavity housing it, filling more than four fifths of the total volume. The forebrain and labyrinth regions of the brain correspond very well to the endocast morphology, while the midbrain and hindbrain do not fit so closely. Our results cast light on the gross neural and endocast anatomy in lungfishes, and are likely to have particular significance for palaeoneurologists studying fossil taxa.     

New and highly sensitive assay for l-5-hydroxytryptophan decarboxylase activity by high-performance liquid chromatography—voltammetry

This paper describes a new, inexpensive and highly sensitive assay for aromatic l-amino acid decarboxylase (AADC) activity, using l-5-hydroxytryptophan (l-5-HTP) as substrate, in rat and human brains and serum by high-performance liquid chromatography (HPLC) with voltammetric detection. l-5-HTP was used as substrate and d-5-HTP for the blank. After isolating serotonin (5-HT) formed enzymatically from l-5-HTP on a small Amberlite CG-50 column, the 5-HT was eluted with hydrochloric acid and assayed by HPLC with a voltammetric detector. N-Methyldopamine was added to each incubation mixture as an internal standard. This method is sensitive enough to measure 5-HT, formed by the enzyme, 100 fmol to 140 pmol or more. An advantage of this method is that one can incubate the enzyme for longer time (up to 150 min), as compared with AADC assay using l-DOPA as substrate, resulting in a very high sensitivity. By using this new method, AADC activity was discovered in rat serum.     

New and highly sensitive assay for l-5-hydroxytryptophan decarboxylase activity by high-performance liquid chromatography—voltammetry

This paper describes a new, inexpensive and highly sensitive assay for aromatic l-amino acid decarboxylase (AADC) activity, using l-5-hydroxytryptophan (l-5-HTP) as substrate, in rat and human brains and serum by high-performance liquid chromatography (HPLC) with voltammetric detection. l-5-HTP was used as substrate and d-5-HTP for the blank. After isolating serotonin (5-HT) formed enzymatically from l-5-HTP on a small Amberlite CG-50 column, the 5-HT was eluted with hydrochloric acid and assayed by HPLC with a voltammetric detector. N-Methyldopamine was added to each incubation mixture as an internal standard. This method is sensitive enough to measure 5-HT, formed by the enzyme, 100 fmol to 140 pmol or more. An advantage of this method is that one can incubate the enzyme for longer time (up to 150 min), as compared with AADC assay using l-DOPA as substrate, resulting in a very high sensitivity. By using this new method, AADC activity was discovered in rat serum.     

Visceral anatomy of ocean sunfish (Mola mola (L., 1758), Molidae,Tetraodontiformes) and angler (Lophius piscatorius (L., 1758), Lophiidae,Lophiiformes) investigated by non-invasive imaging techniques

The purpose of this work is to examine the gross visceral anatomy of ocean sunfish and angler using non-invasive imaging techniques: computed tomography imaging (CT) and magnetic resonance imaging (MRI). Similarities and differences in the internal organisation of these two species are verified. Both species lack a swimbladder and present a significant asymmetry in the hepatic lobes, an elongated bile duct terminating close to the stomach, a compact thyroid embedded in a blood lacuna, and very reduced brain and spinal cord. These observations are important in regard to the close relationships between Tetraodontiformes and Lophiiformes, established by several molecular works, but not yet confirmed by morpho-anatomical data. However the occurrence of these features has to be examined in other taxa before phylogenetic hypotheses are proposed.     

Coenzyme Q blocks biochemical but not receptor-mediated apoptosis by increasing mitochondrial antioxidant protection

Tau in Alzheimer neurofibrillary tangles has been shown to be hyperphosphorylated and CDK5, GSK3, MAP kinase and SAP kinases are the candidate kinases for the phosphorylation of tau. Recently, it was reported that the conversion of p35, the activator of CDK5, to p25 was upregulated in Alzheimer's disease (AD) brains, and that p35 is cleaved to yield p25 by calpain. Here we show that p35 is rapidly cleaved to p25 in rat and human brains within a short postmortem delay and that the conversion of p35 to p25 is partially dependent on calpain activity. Immunoblot analysis of brains prepared from patients with AD or age-matched control individuals with a short postmortem delay revealed no specific increase in the levels of p25 in AD brains, whereas the levels of active form of calpain were increased in AD brains compared to the those in controls. These observations suggest that the conversion of p35 to p25 is a postmortem degradation event and may not be upregulated in AD brains.     

Analysis and description of the evolution of alginate immobilised cells systems

Different immobilised cells models, including very simple ones, can be useful in the fitting of experimental results. However, goodness or the ability to extrapolate results needs to be in accordance with basic observations and these will also suggest models to be proposed. In this paper, observations of calcium alginate/bacteria systems are used to show the ability of basic models to fit classic observations, as well as how new observations, in this case from electronic microscopy, oblige us to think about more complex mechanisms and mathematical treatments. Nevertheless it is not only important to discuss the model type, but also the type of kinetics assumed in the interior of the beads, as well as the internal structure, the boundary conditions related to bead shredding and cell escape and finally, geometrical effects.     

The ontogeny of the urogenital system of the spotted hyena (Crocuta crocuta Erxleben)

Studies were conducted to elucidate the importance of androgen-mediated induction of the extreme masculinization of the external genitalia in female spotted hyenas. Phallic size and shape; androgen receptor (AR) and alpha-actin expression; and sex-specific differences in phallic retractor musculature, erectile tissue, tunica albuginea, and urethra/urogenital sinus were examined in male and female fetuses from Day 30 of gestation to term. Similar outcomes were assessed in fetuses from dams treated with an AR blocker and a 5alpha-reductase inhibitor (antiandrogen treatment). Clitoral and penile development were already advanced at Day 30 of gestation and grossly indistinguishable between male and female fetuses throughout pregnancy. Sex-specific differences in internal phallic organization were evident at Gestational Day 45, coincident with AR expression and testicular differentiation. Antiandrogen treatment inhibited prostatic development in males and effectively feminized internal penile anatomy. We conclude that gross masculinization of phallic size and shape of male and female fetuses is androgen-independent, but that sexual dimorphism of internal phallic structure is dependent on fetal testicular androgens acting via AR in the relevant cells/tissues. Androgens secreted by the maternal ovaries and metabolized by the placenta do not appear to be involved in gross masculinization or in most of the sex differences in internal phallic structure.     

A Novel Procedure for Rapid Imaging of Adult Mouse Brains with MicroCT Using Iodine-Based Contrast

High-resolution Magnetic Resonance Imaging (MRI) has been the primary modality for obtaining 3D cross-sectional anatomical information in animals for soft tissue, particularly brain. However, costs associated with MRI can be considerably high for large phenotypic screens for gross differences in the structure of the brain due to pathology and/or experimental manipulations. MicroCT (mCT), especially benchtop mCT, is becoming a common laboratory equipment with throughput rates equal or faster than any form of high-resolution MRI at lower costs. Here we explore adapting previously developed contrast based mCT to image adult mouse brains in-situ. We show that 2% weight per volume (w/v) iodine-potassium iodide solution can be successfully used to image adult mouse brains within 48 hours post-mortem when a structural support matrix is used. We demonstrate that hydrogel can be effectively used as a perfusant which limits the tissue shrinkage due to iodine.     

Impaired myelin formation in experimental hyperphenylalaninaemia

Abstract— From the 5th to the 20th postnatal day, rats were injected with saline (controls) or phenylalanine (3 mg/g daily). The quantities of cholesterol and glycolipids were significantly lower in the phenylalanine-injected rats, but brain DNA and protein contents were the same in both groups. As a result of the reduced formation of lipids, the hyperphenylalaninaemic brains contained significantly less myelin than control brains, but the gross composition [ratio of protein: cholesterol: galactolipid: phospholipid) of the myelin was unchanged. We suggest that in hyperphenylalaninaemic brains the reduced availability of cholesterol may cause a reduction in the formation of cholesterol-phospholipid-protein complexes in brain, which in turn may limit the formation of myelin.     

Examining the volume efficiency of the cortical architecture in a multi-processor network model

The convoluted form of the sheet-like mammalian cortex naturally raises the question whether there is a simple geometrical reason for the prevalence of cortical architecture in the brains of higher vertebrates. Addressing this question, we present a formal analysis of the volume occupied by a massively connected network or processors (neurons) and then consider the pertaining cortical data. Three gross macroscopic features of cortical organization are examined: the segregation of white and gray matter, the circumferential organization of the gray matter around the white matter, and the folded cortical structure. Our results testify to the efficiency of cortical architecture.     

THE STRUCTURE OF SOME CYTOPLASMIC COMPONENTS OF PLANT CELLS IN RELATION TO THE BIOCHEMICAL PROPERTIES OF ISOLATED PARTICLES

1. Electron micrographs of thin sections of material fixed with buffered osmium tetroxide have been used for comparison of the fine structure of isolated cytoplasmic particles from silver beet petioles and roots of germinating wheat with that of the cytoplasm of the intact cells. 2. Mitochondria of wheat roots have an external double membrane and poorly oriented internal double membranes. As compared with the structures seen in situ, the isolated mitochondria showed evidence of some disorganisation of the fine internal structure, probably due to osmotic effects. The possible influence of such changes on the enzymic properties of the isolated mitochondria is discussed. 3. The isolated plant microsomes are mainly spherical vesicular structures consisting of (a) an outer membrane enclosing (b) either an homogeneous slightly dense material (wheat root microsomes) or some granular dense material (silver beet microsomes) and (c) small dense particles, mostly associated with the vesicle membranes. 4. The cytoplasm of the wheat root cells does not contain any structures similar to the isolated microsomes but has a very dense reticular network, consisting of membranes with associated small dense particles, here called the endoplasmic reticulum. The observations indicate that the isolated microsomes arise mainly by rupture and transformation of the membranes of this structure. The effects of such extensive changes in the lipoprotein membranes on the enzymic activities of the endoplasmic reticulum, as studied in isolated microsomes, is discussed. 5. Meristematic wheat root cells contain structures which consist of smooth membranes with associated vacuoles and are similar to the Golgi zones of animal cells. The membranes of these zones probably contribute to the microsomal fraction under the conditions of preparation used for the enzymic and chemical studies previously reported.     

Neurochemical and activity changes in rats infected with Trypanosoma brucei gambiense

The brains of rats infected with Trypanosoma brucei gambiense were analyzed for their content of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin, and 5-hydroxyindoleacetic acid (5-HIAA). In the caudate of infected rats, dopamine levels increased by 34% and 5-HIAA levels by 20%. DOPAC levels declined by 30% in the caudate, but this change was significant at only P less than 0.1. In the pons/medulla of infected rats the serotonin concentration dropped by 21% and the 5-HIAA concentration rose by 25%. Activity levels in infected rats decreased by 49% (gross movement) and 44% (total movement) relative to those of uninfected control rats.     

Effects of a 48 hour continuous intravenous infusion of CGS 13080-primagrel, a selective thromboxane synthetase inhibitor, on the perinatal and early postnatal period in the guinea pig.

CGS 13080, imidazo[1,5-a]pyridine-5-hexanoic acid, was evaluated for perinatal and postnatal effects in third trimester pregnant guinea pigs and their offspring. The compound was administered via 48 hour continuous intravenous infusion to a group of pregnant guinea pigs (n = 16) at a dose of 3 mg/kg/hr starting on gestational day 52 (via chronically implanted indwelling jugular venous cannulas). A saline control group (n = 12) received equivalent volumes of normal saline 0.5 ml/kg/hr throughout the dosing period. A third group (surgery-sham, n = 16) was subjected to cannulation but not infused. A gross examination of each dam and piglets was conducted at necropsy on day 5 of lactation. The neonatal brains and all gross lesions (maternal and neonatal) were removed and fixed for histopathological examination. Compound-related clinical signs were noted in dams during the dosing phase of gestation. Six guinea pigs developed cephalic lymphatic swelling during the infusion. This observation may be correlated to the reported redistribution of fluid volume to the thorax of guinea pigs given intravenous injections of CGS 13080. There were no compound-induced effects on labor, delivery, or any of the examined reproductive parameters. There were no compound-related clinical signs, or effects on survival, body weight and developmental parameters in the F1 generation. Histopathological examination of the brains and other organs did not reveal any compound-related abnormalities. Based on these results, it was concluded that CGS 13080 did not elicit adverse perinatal and postnatal effects in guinea pigs.     

Nuclear matrix proteins bind very tightly to specific regions of the chicken histone H5 gene.

The nuclear matrix is operationally defined as the structure remaining after nuclease-digested nuclei are extracted with high concentrations of salt. The nuclear matrix is thought to have a role in organizing higher order chromatin into loop domains. We determined whether specific regions of the histone H5 gene were very tightly bound to protein of erythrocyte and liver nuclear matrices in vitro. We demonstrate that DNA fragments spanning sequences 5' to the promoter and the 3' enhancer region of the histone H5 gene, but not DNA fragments spanning the promoter, were very tightly bound to protein of nuclear matrices of erythrocytes and liver. The nuclear matrix consists of internal nuclear matrix and nuclear pore-lamina complex. Recently, we demonstrated that histone deacetylase could be used as a marker enzyme of the internal nuclear matrix. We demonstrate that nuclear pore-lamina complex preparations that were depleted of histone deacetylase activity, and thus of internal nuclear matrix, retained the protein that bound very tightly to the beta-globin and histone H5 enhancers. These results provide evidence that specific regions of the histone H5 gene are very tightly bound to nuclear pore-lamina complex protein.     

Larger agglutinated foraminifera of McMurdo Sound, Antarctica: Are Astrammina rara and Notodendrodes antarctikos allogromiids incognito?

Explorers Cove, an embayment on the oligotrophic western side of McMurdo Sound, Antarctica, is noted for physical and biological similarities to the deep sea. This locality is an important site for foraminiferal biologists because large, deep-sea-like agglutinated taxa are abundant at depths accessible to divers. Using microdissection methods, we found that many of the giant, single-chambered species from this locality display an allogromiid internal organization (i.e., a monothalamous cell body encased by an organic wall or “theca”). Another characteristic feature of these species is the presence of a distinct space separating the cell body and agglutinated test. We used high voltage transmission electron microscopy of thick sections to examine the theca of Astrammina rara, a dominant Explorers Cove species possessing a simple spherical test morphology, and Notodendrodes antarctikos, a distinctive arborescent species. We found that the simple gross morphology of A. rara's agglutinated test belies the complex ultrastructure of its allogromiid-like theca, and that the complex dendritic morphology of N. antarctikos' agglutinated test contradicts the simple ultrastructure of its theca. Additional field and laboratory observations on A. rara revealed that the agglutinated test can be a transient structure. Our observations raise questions regarding the taxonomy and phylogeny of unilocular agglutinated foraminifera and other primitive granuloreticuloseans. The results are also discussed in terms of test function in larger agglutinated foraminifera and the ecology of this important taxon.     

Morphological and Physiological Changes Induced by High Hydrostatic Pressure in Exponential- and Stationary-Phase Cells of Escherichia coli: Relationship with Cell Death

The relationship between a loss of viability and several morphological and physiological changes was examined with Escherichia coli strain J1 subjected to high-pressure treatment. The pressure resistance of stationary-phase cells was much higher than that of exponential-phase cells, but in both types of cell, aggregation of cytoplasmic proteins and condensation of the nucleoid occurred after treatment at 200 MPa for 8 min. Although gross changes were detected in these cellular structures, they were not related to cell death, at least for stationary-phase cells. In addition to these events, exponential-phase cells showed changes in their cell envelopes that were not seen for stationary-phase cells, namely physical perturbations of the cell envelope structure, a loss of osmotic responsiveness, and a loss of protein and RNA to the extracellular medium. Based on these observations, we propose that exponential-phase cells are inactivated under high pressure by irreversible damage to the cell membrane. In contrast, stationary-phase cells have a cytoplasmic membrane that is robust enough to withstand pressurization up to very intense treatments. The retention of an intact membrane appears to allow the stationary-phase cell to repair gross changes in other cellular structures and to remain viable at pressures that are lethal to exponential-phase cells.     

Three-dimensional structure of porcine C5adesArg from 1H nuclear magnetic resonance data

Two-dimensional nuclear magnetic resonance spectra of porcine C5adesArg (73 residues) have been used to construct a list of 34 hydrogen bonds, 27 dihedral angle constraints, and 151 distance constraints, derived from nuclear Overhauser effect data. These constraints were used in restrained molecular dynamics calculations on residues 1-65 of C5a, starting from a folded structure modeled on the crystal structure of a homologous protein, C3a. Forty-one structures have been calculated, which fall into three similar families with few violations of the imposed constraints. Structures in the most populated family have a root-mean-square deviation from the average structure of 1.02 A for the C alpha atoms, with good definition of the internal residues. There is good agreement between the calculated structures and other nuclear magnetic resonance data. The structure is very similar to that recently reported for human C5a [Zuiderweg et al. (1989) Biochemistry 28, 172-185]. Some biological implications of these structures are discussed.