bluuebunny/crossref_metadata_2025 huggingface dataset:
The Mechanical Structure of the Cytoplasm of the Echinoderm Egg Determined by “Gold Particle Method” using a Centrifuge Microscope
Authors: Kaneda Isamu , Kamitsubo Eiji , Hiramoto Yukio
Published: January 2005

A method was developed to investigate the mechanical structure of the cytoplasm based on the movement of an intracellular gold particle subjected to centrifugal acceleration (the gold particle method). The movement of the particle in the cell was observed and recorded with a new centrifuge microscope of stroboscopic type (13). In eggs and oocytes of the echinoderms, Clypeaster japonicus, Asterias amurensis, and Asterina pectinifera, the particle moved in the cytoplasm by an applied centrifugal acceleration in the centrifugal direction, but the course was not exactly straight and the velocity fluctuated during the movement, suggesting the existence of a network structure in the cytoplasm. In fertilized eggs, the movement of the particle by the centrifugal acceleration was impeded by the structures of the sperm aster and the cleavage diaster. The apparent viscosity of the cytoplasm in fertilized eggs changed in parallel to the development of the sperm aster and the mitotic diaster in the cell. These results indicate that the asters are really rigid structures in the cell as previously shown by the magnetic particle method (8).
The Role of Competence in the Cranio‐Caudal Segregation of the Central Nervous System
Authors: Nieuwkoop Pieter D. , Albers Brigitte
Published: January 2005

Left to right thirds of Triturus presumptive prosencephalon show identical developmental potencies after implantation in a neutral Ambystoma environment. Such equipotential grafts were excised from stages between late‐gastrula and mid‐neurula and implanted into the neural plate of an Ambystoma host at different cranio‐caudal levels. Their regional differentiation was independent of the age of the host, but dependent upon the age of the donor material; the older the latter the smaller the portion of the graft which was transformed into more posterior neural structures. Full transformation occurred in stage 11/12 grafts, while pure prosencephalic differentiation took place in stage 16 grafts, demonstrating that the period of competence of the neurectoderm for transformation extends from stage 11/12 up to stage 16. Irrespective of the level of implantation all grafts older than stage 11/12 and younger than stage 16 showed an uninterrupted cranially‐oriented regional differentiation. The medio‐lateral extension of the transformation process is primarily determined by the temporal loss of competence of the implanted neurectoderm. A comparison of grafts implanted at different cranio‐caudal levels showed that transformation is more pronounced the more caudal the level of implantation, so that another factor(s) than competence must also play a role in the regional segregation of the CNS.
Evolutionary Modification of Echinoid Sperm Correlates with Developmental Mode
Authors: Raff Rudolf A. , Herlands Louis , Morris Valerie B. , Healy John
Published: January 2005

A significant fraction of living sea urchin species have completely or partially eliminated the pluteus larval stage and instead develop directly from embryo to adult. Direct developing sea urchins develop from large buoyant eggs. We present data to show that evolution of these large eggs is accompanied by the evolution of spermatozoa with elogate heads, in contrast with the conical sperm heads typical of most echinoids. Two congeneric Australian species, Heliocidaris tuberculata, which develops via a pluteus, and H. erythogramma, a direct developer, were investigated in detail. The sperm of H. erythrogramma have an elongate head (11 μm in length) as compared to the conical sperm head (5.6 μm) of H. tuberculata. Electrophoretic analysis of the sperm histones indicates that no unusual histones or protamines are associated with modified head morphology. Genome sizes were determined by flow cytometry. H. erythrogramma has a haploid genome size of 1.3 pg as compared to a haploid genome size of 0.95 pg for H. tuberculata. Other direct developing echinoids have elongate sperm heads, and co‐evolution of gametes is indicated as a common feature of evolution of direct development in echinoids. The most extreme case, the direct developing cidaroid sea urchin, Phyllacanthus parvispinus, possesses the longest and narrowest sperm head (20 μm × 1 μm) ever observed in an echinoid.
Purification and Characterization of Echinonectin, a Carbohydrate‐Binding Protein from Sea Urchin Eggs
Authors: Veno Patricia A. , Strumski Margaret A. , Kinsey William H.
Published: January 2005

A galactose‐specific carbohydrate binding protein has been identified in eggs and embryos of the sea urchin Lytechinus variegatus. This protein, named echinonectin (Alliegro et al., 1988, J. Cell Biol. 107; 2319–2327) has been described as a cell‐substrate adhesion protein functioning during embryonic development. The purified protein has an apparent molecular weight of 220 kDa and exists as a dimer of apparently identical 110 kDa subunits. The carbohytrate specificity of the purified protein was examined through the use of competition assays. The protein has a marked specificity for galactose and fucose and a higher affinity for polymers of galactose or galactose sulfate such as carrageenan.
Immunolocalization of Fibronectin and Laminin in the Amphibian Intestine During Spontaneous and Triiodothyronine‐Induced Metamorphosis
Authors: Schilt Joseph , Delarue Michel , Dauça Michel
Published: January 2005

Fibronectin and laminin were detected by indirect immunofluorescence in the intestine of Alytes obstetricans (anuran amphibian) during triiodothyronine (T3)‐induced metamorphosis and spontaneous post‐embryonic development. Fibronectin was first detected between a small number of connective tissue cells. As T3‐treatment and spontaneous development progressed, fibronectin became detectable as a fine network extending throughout the whole thickness of the connective tissue and particularly in the core of the developing epithelial folds. During the first week of T3‐treatment and throughout the spontaneous larval period, laminin was present as a linear band within the basement membrane. Between day 6 and 12 of hormonal treatment, an increase in the laminin fluorescent staining was noted. After hormonal treatment for two weeks and at the end of spontaneous metamorphosis, laminin staining was localized within the basement membrane of the folded epithelium and around muscle fibers. These observations indicate that variations in the density and distribution of extracellular matrix molecules are closely related spatiotemporarily to the structural changes occurring in the connective and muscle tissues of the intestine during metamorphosis.
Respiration and Motility in Starfish Spermatozoa at Various Times in the Breeding Season
Authors: Mohri Hideo , Fujiwara Akiko , Daumae Masashi , Yasumasu Ikuo
Published: January 2005

In the spermatozoa of Asterias amurensis, patterns of changes in the respiratory rate and motility following dilution of dry sperm in sea water varied among batches and were classified into three types. The type I spermatozoa were immotile and exhibited quite low respiratory rate. Ethylenediamine tetraacetic acid made the type I spermatozoa motile and elevated their respiratory rate. The type II spermatozoa were also immotile and the respiratory rate remained quite low for about 5 min after the dilution. Thereafter, they spontaneously became motile and the respiratory rate increased. The type III spermatozoa became motile upon their dilution and exhibited high respiratory rate. Differences in the motility and respiratory rate of spermatozoa among batches probably result from degree of their maturation. In moving spermatozoa, the ADP and AMP levels increased at the expense of ATP. 2,4‐Dinitrophenol elevated the respiratory rate only in immotile spermatozoa, which showed a high ATP level and quite low ADP level, but did not made them motile. Oligomycin inhibited the respiration of both motile and immotile spermatozoa. Probably, the respiratory rate is made low by a shortage of ADP in immotile spermatozoa and is enhanced by ADP production due to the initiation of their movement.
Yolk Phosphoprotein Metabolism during Early Development of the Fish, Oryzias latipes
Authors: Murakami Masahiro , Iuchi Ichiro , Yamagami Kenjiro
Published: January 2005

Changes in yolk phosphoproteins of Oryzias latipes embryos during early development were examined by electrophoresis. Four phosphoproteins were identified in the yolk of blastulae by polyacrylamide gel electrophoresis. Two of them were high molecular weight phosphoproteins containing 0.7% (w/w) phosphorus and with similar amino acid compositions to that of vitellogenin. The other two were low molecular weight phosphoproteins, characterized by high contents of phosphorus [12.2% (w/w)] and serine (44.8 mole%) and low contents of aromatic amino acid residues. From these characteristics, together with their behaviors on DEAE‐cellulose chromatography and electrophoresis and low stainability with dyes, the latter two were concluded to be phosvitins. These phosvitins were isolated and partially characterized.

The yolk phosphoproteins, especially the phosvitins, were degraded, their amounts in embryos decreased throughout early development. Studies on the mechanism of endogenous phosphoprotein degradation strongly suggested the participation of some protease(s) that was precipitated on centrifugation of the egg homogenate at 14,000 × g for 10 min.
Gene Expression from Endogenou and Exogenously‐introduced DNAs in Early Embryogenesis of Xenopus laevis
Authors: Shiokawa Koichiro
Published: January 2005

In Xenopus laevis embryogenesis, gene expression from endogenous and exogenously‐introduced DNAs is reported to start only after 12 rounds of cleavage, at the stage called midblastula transition (MBT). In isotopic labeling experiments, however, we found that the synthesis of heterogeneous mRNA‐like RNA occurs from the early cleavage stage, and that gene expression from zygotic genomes occurs sequentially in three characteristically different phases: the pre‐MBT phase, in which heterogeneous mRNA‐like RNA and small amounts of small‐molecular‐weight RNAs are synthesized; the MBT phase, in which there is a large increase in 4S RNA synthesis, and the post‐MBT phase, in which rRNA is also synthesized. Moreover in our studies on the expression of exogenously introduced DNA, we found that circular forms of bacterial chloramphenicol acetyltransferase (CAT) genes connected to viral promoters were expressed from the early cleavage stage, whereas circular forms of genes connected to Xenopus cardiac α‐actin promoter were expressed only after the embryos reached the neurula stage, when the endogenous α‐actin gene started to be expressed. We, therefore, conclude that in Xenopus embryogenesis, DNA‐dependent RNA polymerases II, III and I are activated in this order, and that the promoter, not changes associated with the MBT, probably determine the timing of gene expression.
Manipulating the Mouse Genome: New Approaches for the Dissection of Mouse Development
Authors: Yamamura Ken‐ichi , Wakasugi Shoji
Published: January 2005

In mammals the molecular events that guide pattern formation during embryonic development have been difficult to characterize, partly because of difficulty in observing the development after implantation and in relating the phenotype of a dysmorphic mutation with a specific gene in which the mutation occurs. However, recent advances in the recombinant DNA technique and in manipulation techniques in mouse embryos have made it possible to clone genes involved in the process of development of mice. In addition, advances in human gene mapping and cloning have facilitated studies on mouse development. Thus, mice are now useful in research on developmental biology.
Change in Membrane Fluidity of Sand Dollar Egg Cortices Caused by Ca2+‐Induced Exocytosis: Microscopic Analysis with Fluorescence Anisotropy
Authors: Hirano Ken‐ichi
Published: January 2005

The surface membrane fluidity of sand dollar eggs after exocytosis was investigated by using a specially designed video‐microscope system to measure the fluorescence depolarization of isolated cortices stained with hexadecanoylaminofluorescein. When unfertilized eggs were stained before isolation, the plasma membranes became labeled with fluorescent dye, but cortical vesicles did not. The fluorescence anisotropy of the isolated cortices increased from 0.256 to 0.285 during exocytosis induced by Ca2+. The increased anisotropy was not changed by lowering the Ca2+concentration after exocytosis. Dislodging of cortical vesicles by shearing with a stream of solution had no affect on the anisotropy. These results suggest that the fluidity of the plasma membrane decreases after exocytosis. When cortices were stained after isolation, both plasma membranes and cortical membrane organelles became labeled. These cortices possessed an anisotropy of 0.215. After dislogding the cortical organelles the anisotropy increased to 0.232. These results indicate that the fluidity of the cytoplasmic membrane leaflets of cortical organelles is higher than that of the plasma membrane. Therefore, it was suggested that only the outer leaflet of the plasma membrane becomes less fluid after exocytosis.
Characterization of Antigenic Polypeptides Recognized by Monoclonal Antibodies Specific to the Myoplasm of Eggs of the Ascidian Ciona intestinalis
Authors: Nishikata Takahito
Published: January 2005

The determinants responsible for the differentiation of ascidian larval muscle cells are thought to be contained within the egg myoplasm. To analyze the macromolecules composing the myoplasm, several hybridoma cell lines which secrete monoclonal antibodies specific to myoplasmic components of Ciona eggs have been established (17). In the present investigation, seven of these myoplasm‐specific antigens were characterized according to their molecular features and distribution patterns within the egg cytoplasm. Four of the seven antigenic polypeptides were shown to be components of the cortical cytoplasm, two were related to mitochondria, and one is likely to be a yolk protein. An antigen recognized by IIG6B2 antibody, which inhibited muscle development when injected into fertilized eggs, was a single polypeptide of relative molecular mass about 40,000 and isoelectric point about 5. The antigen was designated myoplasmin‐C1 after its characteristic localization. The IIF9E9 antigen was a single 35‐kDa polypeptide related to mitochondria and was thus designated myoplasmin‐M1. The other five antibodies recognized two or more spots by immunoblotting analysis using two‐dimensional gel electrophoresis. All of these myoplasm‐specific antigens, except for the IIH10D6 antigen, are likely to be produced by the oocyte itself. Synthesis of IIH10D6 antigen seems to be associated with test cells.
Cellular Differentiation in Submerged Monolayers of Dictyostelium discoideum: Possible Functions of Cytoplasmic Ca2+and DIF
Authors: Abe Tomoaki , Maeda Yasuo
Published: January 2005

Cytoplasmic calcium ion (Ca2+) has generally been proposed to be a key factor of numerous cellular processes. Among several agents which might be expected to alter cytoplasmic Ca2+‐concentration ([Ca2+]i), unexpectedly Ca2+‐antagonist TMB‐8 was found to raise considerably [Ca2+]i, and inhibited not only the formation of prespore cells, but also their maintenance in the monolayer cultures of Dictyostelium discoideum. This seems to indicate that higher [Ca2+]i is unfavorable to the prespore differentiation. In this study, we adopted the monolayer culture technique to monitor cell differentiation. However, in high density monolayers there arised a number of unique cells which was highly vacuolated and morphologically intermediate between the stalk and spore cells. These vacuolated cells having both cellulosic wall and spore coat were also induced by differentiation inducing factor (DIF). Thus the monolayer culture system used might be not necessarily qualified to monitor the terminal differentiation of Dictyostelium cells. Nevertheless, the data presented here have strongly suggested that DIF have two physiologically valued roles: 1) Induction of the membrane fusion of vesicles and/or vacuoles (vacuolization), and 2) Induction of the fusion between the cell membrane and vacuole (or vesicle) membrane (exocytosis).
Gastric Pepsin in an Anuran Larva
Authors: Carroll Edward J. , Seneviratne A. Milinda , Ruibal Rodolfo
Published: January 2005

Larval stomach development was studied in the obligate carnivorous larva of the frog Lepidobatrachus laevis. Pepsin producing cells of the larval stomach were identified using rabbit anti‐porcine pepsin and immunohistochemical techniques. Pepsin production was detected at a very early stage of development (stage 24: during opercular development) when the larvae were first competent for feeding. Peptic activity in isolated larval stomachs was demonstrated in a microassay using acid denatured hemoglobin at pH 1.7. The total activity per stomach increased 5,400 fold through the beginning of metamorphosis and the specific activity increased 345 fold through the same period. Electrophoretic analysis of the larval pepsinogens, using a caseinolytic assay revealed the presence of one major pepsinogen at stage 24; two additional isozymes were observed during later larval development. The molecular weight of the isopepsinogens was 34,800.
Cell Population Growth and Area Expansion in Early Chick Embryos During Normal and Abnormal Morphogenesis in vitro
Authors: Ghatpande Satish K. , Mulherkar Leela , Modak Sohan P.
Published: January 2005

The exponential growth and cell population during the early embryogenesis of chick, cultured in vitro correlates with a linear increase in the blastoderm area. To understand the relationship between these parameters and normal morphogenesis, we have used a known teratogen, trypan blue, as a probe. A method is developed in which each new embryonic structure is assigned a rank value of 1 and the total number of ranks allows quantification of development and establishment of a numerical relationship between the size of the cell population, blastoderm area and the morphological development. The teratogen inhibits cell population growth, morphogenetic movements and shaping of organ primordia, but not the epiboly and differentiation of cells which have already invaginated and positioned during primitive streak formation. In contrast, the cell population growth, but not the blastoderm area‐expansion, is correlated with the extent of abnormal development. A graphic analysis of the rank order, log cell number and blastoderm area reveals that these three parameters coordinately regulate morphogenesis. It is suggested that head fold formation is the key event regulating the progress of early morphogenesis.
A Novel Monoclonal Antibody disrupting Cell Type Specific Substratum Adhesion of Frog (Xenopus laevis) Epithelial Cells and Endothelial Cells
Authors: Nomura Kazuya , Tajima Tatsuya , Nomura Hajime , Tsuno Kiyomi , Fujimura Yasuo , Nakajo Nobushige , Yamana Kiyotaka
Published: January 2005

We isolated a mouse monoclonal antibody (FAD‐II) that disrupts cell‐substratum adhesion of amphibian (Xenopus laevis) epithelial cells and endothelial cells. The effect of the antibody was cell‐type specific, and the antibody had no effect on fibroblastic cells while fibronectin peptide blocked cell‐substratum adhesion of all the cell types examined. In developing frog embryos, the epitopes recognized by the antibody were detected in pronephrotic ducts and in other tissue cells of embryos (from stage 33/34 afterwards). In adult tissues, the antibody mainly recognized antigens in extracelluar matrices. The antigens recognized by the antibody seems to be novel glycoepitopes in frog cells.
The Wavy Erythropoiesis of Developing Chick Embryos. Isolation of Each Wave by a Differential Lysis and Identification of the Constituent Erythroid Types
Authors: Cirotto Carlo , Barberini Lanfranco , Arangi Ileana
Published: January 2005

Erythroid carbonic anhydrase (CA) activity of chick embryos from the third day of incubation to the egg hatching has been determined. Five minor activity peaks with maxima at 3, 6, 9, 15 and 17 days of development and a major one with maximum at 19 days have been found. The correlation between the peak distribution and the timing of release into the blood stream of waves of newly produced erythroid cells has been demonstrated on the basis of the following observations: 1) a linear correlation exists between red cell maturation and increase of CA activity; 2) chick red cells undergo lysis in the “Ørskov” medium when their CA activity exceeds a threshold value (23±3 Units/109 red cells); and 3) the lysis kinetics of red cells in the Ørskov medium is proportional to their CA content. We have thus been able to distinguish the immature erythroid forms from the mature ones on the basis of their behaviour in the Ørskov medium. In the blood of developing chick embryos, we have found waves of newly produced red cells at about 2, 4, 7, 10, 16 and 18 days of development.

The same experimental criteria allowed us to detect the waves of red cell production in the erythropoietic organs. One wave has been detected in the blood islands at about 2 days; four waves in the yolk sac at about 5, 6, 11 and 15 days; two waves in the spleen at about 18 and 20 days; two waves in the bone marrow at about 19 days of incubation and 1 day after hatching.

Primitive erythroid cells are produced in the first two waves: that of blood islands at 2 days and that of yolk sac at 5 days. Definitive red cells are produced in the other waves with the exception of the second wave of spleen and of the second wave of bone marrow, which are constituted by red cells of adult type.
Expression of the Retinal Pigmented Epithelial Cell‐Specific pP344 Gene during Development of the Chicken Eye and Identification of Its Product
Authors: Lio Akio , Mochii Makoto , Agata Kiyokazu , Kodama Ryuji , Eguchi Goro
Published: January 2005

In order to understand the transdifferentiation of the retinal pigmented epithelial cells (PECs) into the lens cells at the level of gene expression, a gene, tentatively called pP344 gene, was studied, because its expression appeared to be closely related with the differentiated state of PECs. We analyzed pP344 gene expression during chicken eye development by RT‐PCR and in situ hybridization and also characterized the pP344 protein using antipeptide antibodies. In addition to the previous observation that the transcript of pP344 gene is limited to the pigmented epithelium and not detected in the melanocytes, we show here that the transcript is limited to retinal PECs and is never observed in iris or ciliary PECs. The time course of expression level showed two peaks; the first peak occurred around the 10th day similarly to the expression of melanosome‐related genes, while the second peak occurred just after hatching when PECs had completely differentiated, suggesting that pP344 gene may be related to the function of fully differentiated PECs. Antisynthetic peptide antibodies detected pP344 protein in the culture medium of the PECs but not within the cells. Thus, we concluded that pP344 gene is specifically expressed by the retinal PEC and its product is a secreted protein.
F9 Cells Can be Differentiated toward Two Distinct, Mutually Exclusive Pathways by Retinoic Acid and Sodium Butyrate
Authors: Kosaka Mitsuko , Takeda Masashi , Matsumoto Keishi , Nishimune Yoshitake
Published: January 2005

Both retinoic acid (RA) and sodium butyrate (NaB) induce differentiation in embryonal carcinoma F9 cells. Phenotypic changes caused by RA are irreversible, whereas those of NaB are rapid and reversible. In this study, we investigated the effects of combinations of these two agents on F9 cell differentiation and showed that RA had no effect on the cells induced to differentiate with NaB and vice versa. Thus, F9 cells are induced to differentiate along two distinct pathways which are mutually exclusive.
Cathepsin D Activity in the Vitellogenesis of Xenopus laevis
Authors: Yoshizaki Norio , Yonezawa Satoshi
Published: January 2005

An ovarian extract of Xenopus laevis exhibited in SDS‐PAGE analyses an activity cleaving vitellogenin to lipovitellins under mildly acidic conditions. This activity was pepstatin‐sensitive and inhibited by monospecific anti‐rat liver cathepsin D antibody and thus identified as cathepsin D. Immunoblot analysis showed that two proteins of 43 kDa and 36 kDa immunoreacted with the antibody.

Immunocytochemical staining revealed that the enzyme was located in the cortical cytoplasm of stage I and II oocytes and in small yolk platelets and nascent forms of large yolk platelets in the cortical cytoplasm of stage III oocytes. In stage IV and V oocytes, small yolk platelets retained the immuno‐staining but large yolk platelets decreased it. No immuno‐positive signals were observed in oocytes at stage VI. When examined by immunoelectron microscopy, gold particles indicated that cathepsin D was located on dense lamellar bodies in the cortical cytoplasm of stage I and II oocytes. The particles were located on primordial yolk platelets and on the superficial layer of small yolk platelets in stage III oocytes, while they were sparse or not present at all on large yolk platelets in stage IV and V oocytes. These results indicate that cathepsin D plays a key role in vitellogenesis by cleaving endocytosed vitellogenin to yolk proteins in developing oocytes.
Asymmetry in the Mitotic Spindle Induced by the Attachment to the Cell Surface during Maturation in the Starfish Oocyte
Authors: Satoh Setsuko K. , Oka Mikako T. , Hamaguchi Yukihisa
Published: January 2005

In order to study the dynamic behavior of the mitotic apparatus leading to unequal cleavage, we investigated the distribution of mitotic microtubules (MTs) during maturation division of starfish oocytes. When the mitotic apparatus attached to the cell surface at metaphase, in both the first and second meiotic division, it is revealed, by immunofluorescence, that the MT distribution in the spindle, as well as in the aster, became asymmetric. MTs in the peripheral half spindle increased in number compared with those in the inner half spindle. Furthermore, these results were confirmed in the living cell by polarization microscopy; shortly after the attachment, the birefringence retardation of the peripheral half spindle became greater than that of the inner one, and the difference increased with time during anaphase. By inhibiting the attachment of the mitotic apparatus by means of centrifugation, the MT distribution maintained a symmetrical pattern through mitosis. These results suggest that the attachment of the mitotic apparatus to the cell surface induces the asymmetrical distribution of MTs not only in the aster but also in the spindle. Such a rich distribution of MTs in the peripheral half spindle appears to ensure chromosome exclusion into the polar body by anchoring them firmly to the cell surface of the animal pole.
The Differentiation of a Cell Sorting Mutant of Dictyostelium discoideum
Authors: Ferguson Toby A. , Vozenilek John , West Christopher M.
Published: January 2005

As a result of transfecting Dictyostelium discoideum with an actin 6/lacZ fusion transgene, strain HW80 was created which expresses the β‐galactosidase gene product uniformly throughout development. When mixed with an excess of unmarked wild‐type cells, however, HW80 cells selectively migrate to the positions of anterior‐like cells surrounding the prespore cell mass, and differentiate as if they were anterior‐like cells. As the proportion of HW80 cells is increased, they also sort to positions adjacent to anterior‐like cells and some differentiate as prespore cells. Thus sorting of HW80 cells toward the opposite ends of the prespore cell zone supersedes how they differentiate, suggesting that position influences whether cells differentiate as anterior‐like or prespore cells.
Digitonin Activates Different Sets of Puff Loci Depending on Developmental Stages in Drosophila melanogaster Salivary Glands
Authors: Asaoka Miho , Myohara Maroko , Okada Masukichi
Published: January 2005

We showed previously that treatment of Drosophila melanogaster salivary glands with a mild detergent, digitonin, induces heat shock puffs and many developmentally regulated puffs. To find if the mechanism underlying the puff induction by digitonin is related to the temporal control of gene expression in salivary glands, we examined effects of digitonin on salivary glands at various puff stages from late third instar larva to white prepupa. The results indicate that (a) all the heat shock puffs are induced by digitonin irrespective of the developmental stage of the treated glands, (b) intermolt and early puff loci are always irresponsive to digitonin, and (c) late puff loci respond to digitonin to form puffs only before the stage of their developmentally programmed puffing. Based on the stage at which the locus becomes digitonin responsive, the digitonin‐responsive late puff loci were divided into two groups: group A loci, responsive to digitonin continuously from PS1 until programmed puffing begins, and group B loci, responsive to digitonin only in a short period of time immediately before the programmed puffing. The results suggest that a digitonin‐sensitive suppression mechanism(s) is involved in the temporal control of gene expression in Drosophila salivary glands.
Oviductal Localization of the Cortical Granule Lectin Ligand Involved in the Block to Polyspermy of Xenopus Laevis
Authors: Quill Timothy A. , Hedrick Jerry L.
Published: January 2005

The fertilization layer of Xenopus laevis is formed upon egg activation by the binding of the cortical granule lectin (CGL) to its ligand in the egg extracellular matrix. Using Western blotting methods with biotinylated CGL as a probe, oviductal tissue extracts were examined to determine the site of origin of the CGL ligand. Three glycoprotein ligands of Mrs= > 250,000, 160,000, and 90,000 (reduced samples) were localized to the pars convoluta oviduct immediately posterior to the pars recta oviduct. The binding of CGL to these glycoproteins was inhibited in the presence of 200 mM galactose, but not with 200 mM mannose indicating a specific lectin interaction. The Mrs= > 250,000 and 90,000 glycoproteins were linked by disulfide bonds. In addition, these ligands were secreted from a more anterior region of the pars convoluta oviduct than the Mr=160,000 ligand. No binding of CGL was detected to pars recta secretory granule lysate components. The highest molecular weight CGL ligand seen in the pars convoluta corresponded to the CGL ligand in isolated fertilization envelopes. Thus, the CGL ligand involved in the formation of the fertilization layer is a product of the pars convoluta oviduct.
Modulatory effects mediated by metabotropic glutamate receptor 5 on lateral geniculate nucleus relay cells
Authors: De Labra Carmen , Rivadulla Casto , Cudeiro Javier
Published: January 2005

Glutamate is thought to be the excitatory neurotransmitter in the lateral geniculate nucleus (LGN) of the cat, mediating visual transmission from the retina via ionotropic receptors of both d,l‐α‐amino‐3‐hydroxy‐5‐α‐methyl‐4‐isoxazolepropionate and N‐methyl‐d‐aspartate subtypes. Moreover, glutamate also exerts an important modulatory influence on LGN cells, where metabotropic glutamate receptors (mGluRs) seem to play a crucial role. Here we show in anesthetized adult cats that iontophoretic application of the specific mGluR5 antagonist 2‐methyl‐6‐(phenylethynyl)‐pyridine (MPEP) produced two, distinctly different, effects on LGN neurons. Visual responses to flashing spots and drifting gratings were attenuated (decreased by an average of 59%) in 13 of 23 of the cells but augmented (increased by an average of 60%) in 10 of 23 of the cells. Further, in each case when the specific mGluR5 agonist (R,S)‐2‐chloro‐5‐hydroxyphenylglycine was applied, the effects obtained were the opposite to those of MPEP. Data obtained in a second group of experiments to determine a possible interaction between mGluR5 blockade by MPEP and glutamate ionotropic receptors show that, in the majority of neurons (11 of 15, 73%), the MPEP‐mediated effects seem to be independent of N‐methyl‐d‐aspartate and d,l‐α‐amino‐3‐hydroxy‐5‐α‐methyl‐4‐isoxazolepropionate receptor activity. Our results demonstrate a physiological role for mGluR5 in controlling retinal input and show, in vivo, a more intricate scenario than previously suggested, highlighting the complexity of metabotropic receptor interactions with excitatory and inhibitory elements in the thalamus.
Cortical oscillatory activity during spatial echoic memory
Authors: Kaiser Jochen , Walker Florian , Leiberg Susanne , Lutzenberger Werner
Published: January 2005

In human magnetoencephalogram, we have found gamma‐band activity (GBA), a putative measure of cortical network synchronization, during both bottom‐up and top‐down auditory processing. When sound positions had to be retained in short‐term memory for 800 ms, enhanced GBA was detected over posterior parietal cortex, possibly reflecting the activation of higher sensory storage systems along the hypothesized auditory dorsal space processing stream. Additional prefrontal GBA increases suggested an involvement of central executive networks in stimulus maintenance. The present study assessed spatial echoic memory with the same stimuli but a shorter memorization interval of 200 ms. Statistical probability mapping revealed posterior parietal GBA increases at 80 Hz near the end of the memory phase and both gamma and theta enhancements in response to the test stimulus. In contrast to the previous short‐term memory study, no prefrontal gamma or theta enhancements were detected. This suggests that spatial echoic memory is performed by networks along the putative auditory dorsal stream, without requiring an involvement of prefrontal executive regions.
Pro‐apoptotic protein glyceraldehyde‐3‐phosphate dehydrogenase promotes the formation of Lewy body‐like inclusions
Authors: Tsuchiya Katsumi , Tajima Hisao , Kuwae Toyoyasu , Takeshima Takao , Nakano Toshiya , Tanaka Masaharu , Sunaga Katsuyoshi , Fukuhara Yoko , Nakashima Kenji , Ohama Eisaku , Mochizuki Hideki , Mizuno Yoshikuni , Katsube Nobuo , Ishitani Ryoichi
Published: January 2005

Glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) has long been recognized as a classical glycolytic protein; however, previous studies by our group and others have demonstrated that GAPDH is a general mediator initiating one or more apoptotic cascades. Our most recent findings have elucidated that an expression of a pro‐apoptotic protein GAPDH is critically regulated at the promoter region of the gene. Apoptotic signals for its subsequent aggregate formation and nuclear translocation are controlled by the respective functional domains harboured within its cDNA component. In this study, coexpression of GAPDH with either wild‐type or mutant (A53T) α‐synuclein and less likely with β‐synuclein in transfected COS‐7 cells was found to induce Lewy body‐like cytoplasmic inclusions. Unlike its full‐length construct, the deleted mutant GAPDH construct (C66) abolished these apoptotic signals, disfavouring the formation of inclusions. The generated inclusions were ubiquitin‐ and thioflavin S‐positive appearing fibrils. Furthermore, GAPDH coimmunoprecipitated with wild‐type α‐synuclein in this paradigm. Importantly, immunohistochemical examinations of post mortem materials from patients with sporadic Parkinson's disease revealed the colocalized profiles immunoreactive against these two proteins in the peripheral zone of Lewy bodies from the affected brain regions (i.e. locus coeruleus). Moreover, a quantitative assessment showed that about 20% of Lewy bodies displayed both antigenicities. These results suggest that pro‐apoptotic protein GAPDH may be involved in the Lewy body formation in vivo, probably associated with the apoptotic death pathway.
AMPA receptor desensitization as a determinant of vulnerability to focally evoked status epilepticus
Authors: Fornai Francesco , Busceti Carla L. , Kondratyev Alexei , Gale Karen
Published: January 2005

Within the area tempestas (AT) in the anterior piriform cortex, unilateral microinfusions of GABA receptor antagonists and glutamate receptor agonists trigger brief episodic limbic seizures. In the present study, we document a synergistic effect of coinfusing bicuculline (GABAA receptor antagonist) with either carbachol (muscarinic receptor agonist) or cyclothiazide (inhibitor of AMPA receptor desensitization) but not with glutamate receptor agonists (AMPA, NMDA or kainate) in the rat AT. In particular, coadministration of bicuculline (118 pmol) with either carbachol (328 pmol) or cyclothiazide (1.2 nmol) triggered continuous self‐sustaining seizures (status epilepticus; SE). Cyclothiazide alone did not evoke seizures. Although blockade of NMDA receptors with AP‐7 (100 or 500 pmol) prevented episodic seizures evoked by carbachol or bicuculline alone, it was without effect on the continuous seizures evoked by combined treatments. NMDA‐insensitive self‐sustaining seizures were also evoked by the combination of AMPA and cyclothiazide. Regardless of the mechanism by which SE was evoked, it was prevented only by an AMPA receptor antagonist, NBQX, thus reinforcing the crucial role of AMPA receptors in the transition to SE. Further evidence for AMPA receptor regulation of seizure severity came from the overexpression of the GluR1 AMPA receptor subunit in AT. This resulted in substantially increased severity of bicuculline‐evoked seizures that was reversed by focal application of NBQX. Thus, desensitization of AMPA receptors appears to limit the duration and severity of seizure activity, and a failure of this mechanism, or an overabundance of slowly desensitizing AMPA receptors, predisposes to severe and prolonged seizures.
Functional interaction between the associative parietal cortex and hippocampal place cell firing in the rat
Authors: Save Etienne , Paz‐Villagran Vietminh , Alexinsky Tatiana , Poucet Bruno
Published: January 2005

The hippocampus and associative parietal cortex (APC) both contribute to spatial memory but the nature of their functional interaction remains unknown. To address this issue, we investigated the effects of APC lesions on hippocampal place cell firing in freely moving rats. Place cells were recorded from APC‐lesioned and control rats as they performed a pellet‐chasing task in a circular arena containing three object cues. During successive recording sessions, cue manipulations including object rotation in the absence of the rat and object removal in the presence of the rat were made to examine the control exerted by the objects or by non‐visual intramaze cues on place field location, respectively. Object rotations resulted in equivalent field rotation for all cells in control rats. In contrast, a fraction of place fields in APC‐lesioned rats did not rotate but remained stable relative to the room. Object removal produced different effects in APC‐lesioned and control rats. In control rats, most place fields remained stable relative to the previous object rotation session, indicating that they were anchored to olfactory and/or idiothetic cues. In APC‐lesioned rats, a majority of place fields shifted back to their initial, standard location, thus suggesting that they relied on uncontrolled background cues to maintain place field stability. These results provide strong evidence that the hippocampus and the APC cooperate in the formation of spatial memory and suggest that the APC is involved in elaboration of a hippocampal map based on proximal landmarks.
A new trajectory analysis method for migratory planthoppers, Sogatella furcifera (Horváth) (Homoptera: Delphacidae) and Nilaparvata lugens (Stål), using an advanced weather forecast model
Authors: Otuka Akira , Dudhia Jimy , Watanabe Tomonari , Furuno Akiko
Published: January 2005

Abstract 1 A new method of backward trajectory analysis for planthopper migration is presented. The method consists of two components: an advanced weather forecast model, MM5, for weather simulation, and a migration model for trajectory calculation. The weather forecast model simulates wind fields in which trajectories are calculated by the migration model.

2 It is assumed that planthoppers, Sogatella furcifera and Nilaparvata lugens, are transported at wind speeds and in wind directions. The method is evaluated using a migration event observed at Chikugo in Japan on 25 June 1969, which was recorded in hourly catch data.

3 The results indicate that the takeoff responsible for the migration occurred at 21 UTC (Coordinated Universal Time) on 23 June along the coastal region of Fujian province in China. This is the first time that the source region of this event has been accurately identified. Determinations of the migrating duration and height are also consistent with observations.

4 Although the landing process is not considered in the model, it is shown that the method is able to simulate the migration and accurately estimate various parameters. This study also shows the importance of high‐quality weather simulation.
Termite damage to maize grown in agroforestry systems, traditional fallows and monoculture on nitrogen‐limited soils in eastern Zambia
Authors: Sileshi G. , Mafongoya P. L. , Kwesiga F. , Nkunika P.
Published: January 2005

Abstract 1 Termites cause significant damage to maize and other crops in southern Africa. Several studies were conducted with the objective of determining the difference in termite damage to maize in various land use systems between monoculture maize, maize grown using traditional fallows and improved fallows.

2 In an experiment conducted at four sites on noncoppicing fallows, maize planted after Tephrosia candida 02971 fallows had lower termite damage compared with fully fertilized monoculture maize. However, the termite suppression was not low enough to warrant rotation of noncoppicing fallows for termite management..

3 In four experiments comparing termite damage to maize grown in monoculture and in coppicing fallows, fully fertilized monoculture maize had a higher percentage of lodged plants compared with maize grown in pure Leucaena leucocephala, Gliricidia sepium and Acacia anguistissima fallows or in a mixture of A. anguistissima + Sesbania sesban or Tephrosia vogelii + S. sesban.

4 More than 50–75% of the variance in maize yield was explained by preseason inorganic nitrogen and termite damage. However, termite damage to maize was not influenced by inorganic nitrogen, which represents nitrogen readily available to maize. The decomposition rate of biomass (related to lignin + polyphenol to nitrogen ratio) and water retention under fallows also appeared to influence termite damage.

5 It is concluded that maize grown in L. leucocephala, G. sepium, A. anguistissima and S. sesban fallows suffers less termite damage and produces maize yields comparable with conventionally tilled and fully fertilized monoculture maize.
Larval survival and development of susceptible and resistant Ostrinia nubilalis (Lepidoptera: Pyralidae) on diet containing Bacillus thuringiensis
Authors: Huang Fangneng , Buschman Lawrent L. , Higgins Randall A.
Published: January 2005

Abstract  1 Larval survival and development of Dipel‐susceptible and ‐resistant strains of European corn borer, Ostrinia nubilalis (Hübner), were assayed using diets incorporating low doses of a commercial formulation of Bacillus thuringiensis var. kurstaki Berliner (Dipel ES).

2 Larval mortality, growth and development, pupation rate and pupal weight were not significantly different between Dipel‐susceptible and ‐resistant strains when larvae were reared on a nontoxic control diet.

3 Larval mortality of Dipel‐resistant larvae did not significantly change as Dipel concentration increased at the tested concentrations, whereas mortality of Dipel‐susceptible larvae increased dramatically as Dipel concentration increased.

4 Larval development was significantly delayed when larvae were fed diets containing low doses of Dipel.

5 Pupation rate and pupal body weight declined as Dipel concentration increased but it decreased faster for the susceptible strain than for the resistant strain.
Laboratory and greenhouse evaluation of a synthetic host volatile attractant for Colorado potato beetle, Leptinotarsa decemlineata (Say)
Authors: Martel J. W. , Alford A. R. , Dickens J. C.
Published: January 2005

Abstract 1 The attractiveness of potato plants treated with a synthetic host volatile blend [(Z)‐3‐hexenyl acetate (+/–)‐linalool, and methyl salicylate] to newly emerged and 5‐day‐old adult Colorado potato beetle, Leptinotarsa decemlineata (Say), was compared at four doses against untreated control plants and plants treated with an azadirachtin‐based antifeedant in greenhouse cage arenas.

2 Attractant‐treated plants (derived release rates of 0, 5.7, 17.1 or 57 µg/h) were significantly more attractive than untreated control plants to newly emerged and 5‐day‐old adults only at 57 µg/h.

3 Attractant‐treated plants were significantly more attractive than antifeedant‐treated plants to newly emerged and 5‐day‐old adults at the 5.7 µg/h treatment level and higher. Mean insect density on attractant‐treated plants in the attractant/antifeedant study was significantly higher than in the attractant/control study.

4 Habituation to the synthetic attractant was evaluated by exposing adult beetles to the synthetic attractant for 0, 1, 2.5, 4, 8, 12 or 16 h, before release into a wind tunnel in which an attractant‐baited plant model was placed at the upwind end. Insects exposed to the synthetic host attractant for ≤ 8 h moved to the synthetic attractant‐baited plant model whereas insects exposed to the synthetic host attractant for 12 and 16 h did not. Furthermore, beetles exposed to the synthetic attractant for 0 and 1 h moved at rates greater than, or equal to, the median whereas beetles exposed for longer time periods moved at rates significantly less than the median.

5 These results demonstrate the potential for using the synthetic plant attractant and an antifeedant as components in a stimulo‐deterrent strategy for management of the Colorado potato beetle as shown by us in another study.
Primary succession of soil Crenarchaeota across a receding glacier foreland
Authors: Nicol Graeme W. , Tscherko Dagmar , Embley T. Martin , Prosser James I.
Published: January 2005

The development of soil archaeal community structures in relation to primary succession in bulk and rhizosphere soil was examined across the forefield of the receding Rotmoosferner glacier in Austria. Using cloning and denaturing gradient gel electrophoresis (DGGE) analysis of reverse transcription polymerase chain reaction (RT‐PCR) products of extracted 16S rRNA, archaeal community structure was compared over a chronosequence representing approximately 150 years of soil development and to reference sites outside the glacier forefield, representing soil exposed for approximately 9500 years. Archaeal community composition was found to be dominated by members of the non‐thermophilic or Group 1 Crenarchaeota, where a dramatic yet highly structured successional sequence was observed. Succession over the 150 years sequence could be identified as occurring in three stages, each of which had a phylogenetically distinct 1.1b crenarchaea community with those organisms present in pioneering and intermediate stages belonging to a lineage distinct from those in developed soils. Climax communities also contained organisms belonging to three other major non‐thermophilic crenarchaeal lineages. Comparison of archaeal communities in the rhizosphere indicated that plant species composition was not the major driver of specific crenarchaeal populations. These results indicate the potential role of soil crenarchaea in the development of soil substrates, as well as ecological diversity within and between major Group 1 lineages.