Functional morphology and light-gathering ability of podocopid ostracod eyes and the palaeontological implications

The optical features of lateral ocelli of the eye were examined in 29 Recent species of the major ostracod group Podocopida using a theoretical morphological model. A cuticular lens–tapetum model was used for this purpose. Ray tracing was simulated on each model in order to assess the light-gathering abilities of the various forms of eyes. The results of computer simulations and morphospace analyses indicated that the light-gathering ability of the eye is dominantly affected by the thickness and curvature of the outer surface of the lens. On the basis of a combination of form and light-gathering ability, four eye types (LG1, LG2, MG, and HG) were recognized. The results of the phototactic experiment and the light intensity from each microhabitat were concordant with estimated scores on the light-gathering abilities using the theoretical models. Phylogenetic analyses and the fossil record indicate that the MG type is the most plesiomorphic, and that the other types derive from this. The present study also suggests that the optical structure that determines the light-gathering ability is closely related to the development of surface ornamentation on the valve.  © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 147 , 97–108.     

Effects of wing-pad removal and corpus allatum implantation on development of wings, flight muscles, and related structures in the striped ground cricket, Allonemobius fasciatus

ABSTRACT. Removal of a hindwing pad from late instar nymphs of the striped ground cricket, Allonemobius fasciatus DeGeer (Gryllidae) inhibits the formation of long-winged adults. All nymphs become short-winged when their hindwing pad is removed during the sixth (penultimate) instar or during the first 2 days of the seventh instar. When a hindwing pad is removed on day 4 of the seventh instar or later, there is no effect on wing development and at least 50% of the crickets emerge as long-winged adults as in controls.
The period sensitive for removal of a hindwing pad varies among different structures, e.g. elytra, hindwings, flight muscles, and the acrotergite of the first abdominal segment. As a result, some intermediate forms are produced when a hindwing pad is removed in the middle of the seventh instar.
Implantation of corpora allata (CA) into late instar nymphs also inhibits formation of long-winged adults. When CA are implanted on day 2 or 3 of the seventh instar, some of the resulting adults have abnormally short elytra. Implantation of CA at an earlier stage produces supernumerary (eighth instar) nymphs.     

New host record for three scuttle flies, Megaselia flava, M. kanekoi and M. gotoi (Diptera: Phoridae), on the poisonous fungus Amanita ibotengutake (Agaricales: Amanitaceae)

We identified three species of fungivorous scuttle fly –Megaselia flava, M. kanekoi and M. gotoi– from eight fruit bodies of a fungus, Amanita ibotengutake, which has not previously been recorded as the host of these flies.     

GENERAL ACCOUNTS ON THE OÖCYTE GROWTH AND THE IDENTIFICATION OF VITELLOGENIN BY MEANS OF IMMUNOSPECIFICITY IN THE COCKROACH, BLATTELLA GERMANICA (L.)

The female Blattella germanica pushes out an oötheca 11 days after adult ecdysis and carries it for about 25 days until nymphs hatch out. The terminal oöcyte begins to accumulate yolk abruptly 4 or 5 days after adult ecdysis and grows fully on day 10 when its volume reaches 180 times as compared to that at adult ecdysis.
Vitellogenin, the vitellogenic female-specific protein, was identified by immunoelectrophoresis and Ouchterlony's test. Fluctuation of vitellogenin in the blood, ovary and embryo at various stages was analyzed. Vitellogenin appears in the female blood 3 or 4 days after adult ecdysis and disappears soon after terminal oöcytes have been released to an oötheca. In the ovary, it appears 4 or 5 days after adult ecdysis and disappears when terminal oöcytes leave the ovary. It remains in embryos until shortly before hatching, but is absent in newly hatched nymphs.     

抑前胸腺肽在家蚕体内的活性作用

家蚕Bombyx mori抑前胸腺肽是昆虫脑神经肽的一种,体外实验表明它能抑制处于活动时期的家蚕前胸腺合成蜕皮激素,因此抑前胸腺肽可能对昆虫的变态起着重要的作用。将抑前胸腺肽以不同的浓度分单一注射和加强注射导入家蚕体内,不同的时间间隔取样,利用蜕皮激素放射免疫分析方法,观察到了抑前胸腺肽在家蚕体内的活性作用以及引起家蚕体内血淋巴中蜕皮激素浓度的动态变化,首次证明了抑前胸腺肽在体内对家蚕前胸腺合成蜕皮激素有强烈的抑制作用。     

Establishment of a Murine Model for Metastasis of Cytokine-Producing Tumor to the Brain

The A375 cell line, derived from human malignant melanoma, has characteristics of interleukin-6 (IL-6) production. By using this cell line, we have investigated a murine metastasis model of IL-6-producing tumors to the brain by injecting A375 cells directly into the left cardiac ventricle. Nude mice were anesthetized with intraperitoneal injection of pentobarbital sodium. Next, A375 cells suspended in phosphate-buffered saline (PBS) were injected into the left cardiac ventricle of mice. An intracardiac injection of 10⁵ cells developed tumor colonies in the brain after 4 to 6 weeks. Metastatic cells were found in every lobe of the brain. An immunocytochemical study revealed IL-6 production by A375 cells at the metastatic sites in the brain. By the transfection of genes encoding proteins into A375 cells, a novel model of protein expression in the brain in vivo could be constructed. Our system does not require great skill. Our experimental model will facilitate future studies of the local effects of proteins in the brain.     

The Inhibitory Effect of 5-Bromodeoxyuridine on the Programmed Cell Death in the Chick Limb

The inhibitory effect of 5-bromodeoxyuridine (BrdU) on the programmed cell death in interdigital mesenchyme of a chick leg bud was studied using vital staining and histological methods. A single administration of BrdU at day 6 1/3 specifically inhibited the programmed cell death in the mesenchyme of interdigital areas of a leg bud, resulting in the formation of a web-like structure. No inhibitory effect was observed on general development of limb buds. Hoechst 33258 staining revealed that many cells of interdigits incorporated BrdU into their nuclei. The simultaneous administration of thymidine blocked the BrdU effect.     

FORMATION OF GERM CELL-LIKE CELLS IN THE PERITONEAL EPITHELIUM OF THE TESTES OF ESTROGEN-TREATED ADULT MALES OF THE JAPANESE RED-BELLIED NEWT, CYNOPS PYRRHOGASTER PYRRHOGASTER

Columnar cells of the peritoneal epithelium in slender cords of the testes were examined in normal and estradiol benzoate-treated Japanese red-bellied newt, Cynops pyrrhogaster pyrrhogaster, by light and electron microscopy. In normal newts, the peritoneal epithelium covering the slender cord consists of columnar cells, which contain extraordinarily large, oval or spindle-shaped nuclei with conspicuous indentations. The nucleus contains chromatin granules and the cytoplasm is filled with numerous tonofilaments. The primordial germ cells are scattered throughout the slender cord, and each cell is surrounded by a few follicle cells. Between the germ cells and follicle cells there are microvilli-like processes. The nucleus of primordial germ cells is multilobate and has electron lucent areas, dispersed chromatin and several electron-dense nucleoli. In the lighter cytoplasm, the nuage material is found very near to nuclear pores, and is frequently seen among the mitochondria. The nucleolus-like body is not associated with other organelles. The primary spermatogonia have bilobate nuclei. It is remarkable that most of the cytoplasmic organelles are found in the deep nuclear indentations. The nuage material and nucleolus-like body are well developed in the cytoplasm. After treatment of newts with estradiol benzoate for one year, four types of cells can be distinguished in the peritoneal epithelium. One type is quite different from the columnar cells. These newly appeared cells are large and light in appearance. Their nucleus is highly lobate, and contains dispersed chromatin and several nucleoli with compact electron dense material in its periphery. The cells are characterized by the presence of nuage material and nucleolus-like bodies in the cytoplasm. There are microvilli-like processes between these cells and adjacent elongated cells. These ultrastructural characteristics of the light cells are very similar to those of primordial germ cells and/or primary spermatogonia in normal testes. These findings suggest that the light cells which appear in the peritoneal epithelium of the testes on administration of estrogen may be germ line cells.