Unpaired Part Research Articles

Spatial organization of fibroblast and spermatocyte nuclei with different B-chromosome content in Korean field mouse, Apodemus peninsulae (Rodentia, Muridae).

Korean field mouse (Apodemus peninsulae) shows a wide variation in the number of B chromosomes composed of constitutive heterochromatin. For this reason, it provides a good model to study the influence of the number of centromeres and amount of heterochromatin on spatial organization of interphase nuclei. We analyzed the three-dimensional organization of fibroblast and spermatocyte nuclei of the field mice carrying a different number of B chromosomes using laser scanning microscopy and 3D fluorescence in situ hybridization. We detected a co-localization of the B chromosomes with constitutive heterochromatin of the chromosomes of the basic set. We showed a non-random distribution of B chromosomes in the spermatocyte nuclei. Unpaired B chromosomes showed a tendency to occur in the compartment formed by the unpaired part of the XY bivalent.

Male organs of African catfish (<i>Clarias gariepinus</i>) in spawning and non-spawning periods in Maiduguri, Borno State, Nigeria

The study was undertaken to investigate the gross reproductive organs of wild male Clarias gariepinus in spawning and non-spawning periods. Twenty mature males of C. gariepinus comprising of ten each during both periods were used. They weighed an average of 532 ± 8.32 gm during spawning and 510.8 ± 9.27 gm during non-spawning season and measured a standard body length of 43.2±4.72 cm and 42.1±2.48 cm during spawning and non-spawning seasons respectively. All fish were sourced from Gamboru fish market, Maiduguri and transported live to the gross Anatomy laboratory, Department of Veterinary Anatomy University of Maiduguri. Each fish was euthanized using tricaine anaesthetic at 8 drops/litre of water. The reproductive organs were removed en mass using scalpel, forceps, and scissors. Then the number of seminal vesicles were determined during spawning (37.8 ± 4.53) and non-spawning (36.32 ± 3.68) periods. The organs were seen consisting of lobular testes, milt duct, seminal vesicles, bulbourethral gland and papilla, which are whitish and milky colour appearances in spawning and non-spawning periods respectively. The milt duct which have the paired and unpaired part were also seen clearly in non-spawning period but relatively invisible in spawning period.Keywords: Bulbourethral gland, Maiduguri, seminal vesicles, testes, Wild African catfish

Sexual dimorphism in prophase I of meiosis in the Northern mole vole (Ellobius talpinus Pallas, 1770) with isomorphic (XX) chromosomes in males and females

The synaptonemal complex (SC) surface-spreading technique was used to visualize the process of chromosome synapsis in spermatocytes and oocytes of E. talpinus Pallas, 1770, a species with the XX sex chromosome system in both males and females. We used electron microscopy and immunofluorescent localization of synaptonemal complex protein (SCP3) and centromeric proteins to analyze the structure and behaviour of synaptonemal complexes in prophase I of meiosis, aiming to reveal signs of meiotic sexual dimorphism in this species. We present evidence of considerable differences in the structure and behaviour of the axial structures of sex bivalents in male and female meiosis, despite the isomorphic G- and C-banding patterns of mitotic sex chromosomes. During meiotic prophase I, the sex bivalent in females behaved as autosomal bivalents, but it was not involved in the formation of the bouquet configuration or it was the first to leave it. The XX chromosomes of males formed closed sex bivalents. Only short tracts of SC were formed at both ends of the sex bivalent, while large middle segments of the lateral elements remained unpaired. The male sex chromosomes also formed characteristic “sex bodies”. In fact, electron microscopy revealed dense nucleolus-like bodies associated with unpaired parts of the axial elements. These regions of the sex chromosomes were poorly immunostained, because the distribution of SCP3 had a peculiar powder-like pattern, but SCP3 was not associated with the nucleolus-like bodies. We also revealed signs of sexual dimorphism in the dynamics of formation and destruction of autosomal SCs. In males, the total SC length was shorter than in females. The chromosome bouquet configuration was preserved up to the stage of early pachytene in females. The bouquet configuration in males was not expressed. At late pachytene, gaps were revealed in the structure of autosomal SCs in spermatocytes immunostained with antibodies to SCP3. The pattern of distribution of these gaps was comparable with the G-banding patterns of mitotic chromosomes.

Mask Scale Adjustment (MSA) in Stereo Matching

We proposed mask scale adjustment method for stereo matching inspired by volume perception in human visual perception. Stereo matching is required to obtain 3-dimensional (3D) information from stereo pair images, and many sophisticated approaches have been developed to precisely obtain correspondence in stereo pairs. We found a forgotten problem not solved by these methods inherent in stereo matching and originating in the scale difference between stereo pair images. We propose mask scale adjustment for improving matching performance, especially in adjacent areas of binocularly unpaired parts, on objects with curved surfaces. Implementing our proposal into conventional stereo matching would yield more precise 3D information on objects and realize of volume perception.

Kiss singularities of Green's functions of non–strictly hyperbolic equations

Let us consider the equation $$L\left( {\frac{\partial }{{\partial t}},\frac{\partial }{{\partial {x_1}}}, \ldots \frac{\partial }{{\partial {x_n}}}} \right)u\left( {t,x} \right) = f\left( {t,x} \right)$$ (32.1) , where \(L\left( {\frac{\partial }{{\partial t}},\frac{\partial }{{\partial {x_1}}}, \ldots \frac{\partial }{{\partial {x_n}}}} \right)u\left( {t,x} \right) = f\left( {t,x} \right)\) is a homogeneous polynomial of degree m and x = (x 1,..., x n ). It is called strictly hyperbolic if, for any ξ ≠ 0, the equation L(v ξ) = 0 has m distinct real roots v 1 ..., v m . Surface S : L(1, ξ) = 0 is known as the slowness surface. It consists of [m/2] non-overlapping ovals which enclose the origin. When m is odd, one more component, an unpaired part, is added [1]. A set Γ of points (t, x), such that the plane t + (x, ξ) = 0 is tangential to S, is called a characteristic cone and consists of [(m + 1)/2] sheets. The section of the cone by the plane t = 1 is known as the wave surface.

Volume Perception with Binocular Viewing

We reported earlier that the binocularly unpaired region plays an essential role in the perception of the volume of a solid object (Idesawa, 1991 Japanese Journal of Applied Physics30-4B L751 - L754). We have investigated this volume perception using both illusory and physical objects. The illusory objects used in the tests were of two types, either with or without binocularly unpaired contours. The physical objects used as stimuli in the present experiments were half-moon-shaped textured cylindrical objects, one with and one without a binocularly unpaired region. A rectangular probe was placed beyond the object, and subjects were asked to adjust its position in depth until they felt that the probe just touched the object. We found that the chosen depth settings were systematically ‘behind’ the objects with unpaired parts, while they were almost ‘correct’ for the objects without unpaired parts. In the former case, subjects thus had the impression that the volume extended further back. We also found that the rim of an object is important for volume perception, especially for objects without textures. A typical example is an imaginary cone occluding two disks, one a little larger than the bottom surface and placed near the bottom, the other a small one located just beyond the top. A complete illusory cone with volume (just like a ‘Santa cap’) could be seen!

Binocular displacement of unpaired region.

Binocular displacement of binocularly unpaired parts of the stimulus was examined by means of the Poggendorff figure. The Poggendorff figure can be used to investigate displacement since lateral displacement of the transversal may cause bias in judgments of its collinearity. In experiment 1, the transversal had a disparity, and thus binocularly unpaired parts, relative to the rectangle. The magnitude of the Poggendorff illusion should not have changed by addition of binocular disparity if displacement occurred. There was no or slight change when the transversal was seen behind the rectangle, but there was significant decrease when the transversal was seen in front of the rectangle, suggesting absence of displacement in this case. There were two possible explanations. One was that displacement depended on the positional relation between the unpaired stimuli and the binocularly presented rectangle, ie the occlusion constraint, which the case with the transversal in front did not satisfy. The alternative was that the decrease was due to the perceived front depth of the transversal, and not related to binocular displacement at all. In order to discriminate between these two possibilities, the transversal was reduced to only the unpaired parts, resulting in dichoptic stimulation in experiment 2. In this stimulus, the positional relation between the unpaired and the paired stimuli was the same as in the previous experiment, yet no front depth could be perceived. The results showed similar asymmetry as in experiment 1. Thus we conclude that binocular displacement depends on the positional relation between the unpaired and the paired stimuli, regardless of their perceived depth. This may imply that binocular displacement is not symmetric about the sign of disparity, hence that it is not just averaging but is a reconstruction of the spatial layout of objects in the outside world to keep the visual direction of the unsuppressed unpaired region veridical by using explicit cues to depth discontinuity.

Mutagenesis and self-ligation of the self-cleavage domain of the satellite RNA minus strand of tobacco rinspot virus and its binding to polyamines

Several mutants for the minus strands of the self-cleaving domain of the satellite RNA of tobacco ringspot virus have been synthesized by joining chemically synthesized oligoribonucleotides with RNA ligase. Kinetic properties of the enzyme strands (50 nucleotides) against substrates (15-mer and 18-mer) were investigated. Structural properties of the unpaired part in the cleavage region were estimated from mutagenesis. The catalytic domain alone was proved to be responsible for the rejoining reaction of cleaved substrates. It was also found that the ribozyme could be divided into two strands without loss of activity. Effects of concentration of magnesium ion and polyamines on the cleavage reaction for the two-stranded ribozyme are also reported.

The seminal vesicle of the African catfish, Clarias gariepinus. A histological, histochemical, enzyme-histochemical, ultrastructural and physiological study.

The seminal vesicle of the African catfish, Clarias gariepinus, consists of 36-44 fingerlike lobes built up of tubules in which a fluid is secreted containing acid polysaccharides, acid-, neutral- and basic proteins, and phospholipids. In this fluid sperm cells are stored. The seminal vesicle fluid immobilizes the sperm cells. After ejaculation, it prolongs the period of sperm activity. The seminal vesicle fluid is secreted by the epithelium lining the tubules. The tubules in the proximal part of the lobes are predominantly lined by a simple cylindrical and those of the distal part by a simple squamous epithelium. These epithelial cells contain enzymes involved in energy-liberating processes, the enzyme activities being proportional to the height of the cells. Interstitial cells between the tubules have enzyme-histochemical and ultrastructural features indicative of steroid biosynthesis. Similar characteristics are found in testicular interstitial cells. The most rostral seminal vesicle lobes and the most caudal testicular efferent tubules form a network of tubules that opens at the point where the paired parts of the sperm ducts fuse with each other. The tubules of most seminal vesicle lobes, however, form a complex system that fuses with the unpaired part of the sperm duct.

Bacillus thuringiensis a potential control agent for the Colorado potato beetle

In laboratory tests conducted to determine the effectiveness of the exotoxin ofBacillus thuringiensis against the Colorado potato beetle,Leptinotarsa decemlineata (Say), applications sprayed on tomato foliage at dilutions ranging from 10−1 through 10−4 killed 90% of the 1st and 2nd stage beetle larvae. As the dosage decreased, the time to achieve this level of mortality increased from 4 to 9 days. Adult beetles were not killed by these treatments; however they did cease feeding. In field tests, the highest dosages ofB. t. sprayed on either tomato or potato plants provided adequate or nearly complete protection when applied weekly. Young larvae that ingested sub-lethal doses developed into adults with atrophied mouthparts and antennae, transformations of the paired parts of the labial palps into an unpaired part, the appearance of a tarsal-like claw on a palp, and malformation of the cranial sclerities.

The influence of ovine follicle stimulating hormone (FSH) and luteinizing hormone (LH) on the male reproductive system and the skin of the Mediterranean blenniid fish Blennius sphinx (Valenciennes).

AbstractThe Mediterranean Blenniid fish Blennius sphinx has a unique male reproductive system: the testes lie close to voluminous lipid bodies through which the sperm must pass. The tubules, through which the sperm travel, lead to a collection duct opening ventrally into locally enlarged sperm ducts. These taper off caudally and join in an unpaired terminal section which opens into a genital papilla. Slightly posterior to the union, the duct forms two blind pouches extending laterally to the caudal third of the testes. In addition, during spawning, Blennius sphinx shows a glandular system of unknown function in the first and second spines of the anal fin.In this paper, the reactions of the sex‐linked structures described above, and of the mucous cells in the epidermis of post‐spawning fishes, to injections of mammalian FSH and LH are studied. By LH‐treatment the proportion of the animals with fully active testes is increased from 36% (controls) to 83%. The height of the lipid body is increased about 26% by LH‐injections, as compared with the controls. This effect is correlated with an increase in the size of the lipid vacuoles of about 28%. In the epithelium of the paired portions of the sperm duct, LH promotes the formation of aldehyde fuchsin‐positive granules in the cells. The proportion of this type of secretion rises from 18% (controls) to 68% after LH‐treatment. In the terminal unpaired part of the sperm duct, within the genital papilla, the epithelium is thickened by about 38% by this hormone. Injections of LH decrease the height of the blind pouch epithelium, which is well developed, and actively secreting in most of the controls. They also suppress secretion and vascularisation in this structure. LH promotes the formation of the anal gland system, increasing the proportion of the animals with maximally developed glandular systems from 0% (untreated controls) or about 17% (H2O‐treated controls) to 91%. This effect is correlated with an increase of the diameter of the single glands of about 40%. This is also the case in FSH‐treated fishes (23%). The number of the mucous cells in the epidermis decreases by 46% and 45% after FSH‐ and LH‐treatment, respectively. In no case were the effects strictly correlated with the hormone dose. The problems of the action of mammalian gonadotrophins, especially FSH, in fishes; the possible functions of the organs associated with the male genital tract of Bl. Sphinx, and the possible role of the mucous cells in the osmoregulation of fishes are discussed.

Sex-limited DDT-Resistance in House-flies

A NEW mechanism of inheritance of DDT-resistance has been investigated in a selected strain of house-flies (Musca domestica L.) wherein resistance is manifest only in males. Genetic tests have shown that the resistance is transmitted by males but not by females. It is therefore determined either directly by a Y-chromosome factor or, like sex in Drosophila, by the balance between the unpaired parts of X and Y and the rest of the chromosome set.

Comportamento dos cromossômios no gênero Hypselonotus (Hemiptera -Coreidae)

The three species studied have 19 chromosomes, being one heterochromosome, one pair of microchromosomes and 8 pairs of autosomes. The microchromosomes of Hypselonotus fulvus are amongst the largest we know. During the synizesis, in Hypselonotus fulvus, we can see in several strands that scape from the chromatic knot a place in which they are widley open. As, in that phase the chromosomes have both ends converging to the same place, the openings suggest a side-to-side pairing of the chromosomal threads. The tetrads are like that studied by Piza (1945-1946). The bivalents are united side by side at their entire length. The unpaired part at the midle of the bivalents gives origin to the arms of the cross-shapede tetrads. The chromosomes have a kinetochore at each end. The bivalents sometimes unite their extremities to form ring-shaped figures, which open themselves out before metaphase. The tetrads are oriented parallelly to the spindle axis. At telophase the kinetochores repeli one another, the chiasmata, if present, slip toward the acentric extremities and the chromosomes rotate in order to arrange themselves parallelly to the axis of the new spindle. Separation is therefore through the pairing plane. In the spermatogonial anaphase of Hypselonotus subterpunctatus the chromosomes are curved to the poles, like those described by PIZA (1946) and PIZA and ZAMITH (1946). The sex chromosomes in Hypselonotus interruptus and Hypselonotus fulvus appears longitudinally divided. It is oriented with the ends in the plane of the equator and its chomatids separate by the plane of division. In the second division the sex chromosome, provided as it is with an actve klnetochore at each end, orients itself with its length parallelly to the spindle axis and passes undivided to one pole. Sometimes it is distended between the poles. This corresponds to case (a) established by PIZA (1946) for the sex chromosomes of Hemiptera In Hypselonotus subterpunctatus the sex chromosome, in the first division of the spermatocytes, orients like the tetrads and divides transversaly. In the second division, as its kinetochore becomes inactive, it remans monocentric, does not orient in the spindle, and is finally enclosed in the nearer nucleus. In the secondary telophase it recuperates its dicentricity like the autosomal chromatids. This behavior corresponds to case (c) of PIZA (1946).