Immunocytochemical localization of tubulins in spermatids and spermatozoa of Euptoieta hegesia (Lepidoptera: Nymphalidae)

A comparative analysis of the distribution of tubulin types in apyrene and eupyrene sperm of Euptoieta hegesia butterflies was carried out, also verifying the presence of tubulin in lacinate appendages of the eupyrene sperm. Ultrathin sections of LR White embedded spermatids and spermatozoa were labeled for alpha, beta, gamma, alpha-acetylated and alpha-tyrosinated tubulins. Apyrene and eupyrene spermatids show the same antibody recognition pattern for tubulins. All tubulin types were detected in axonemal microtubules. Alpha and gamma tubulins were also detected on the cytoplasmic microtubules. However, for beta and tyrosinated tubulins only scattered labeling was detected on cytoplasmic microtubules and acetylated tubulin was not detected. In apyrene and eupyrene spermatozoa only the axoneme labeling was analyzed since cytoplasmic microtubules no longer exist in these cells. Alpha, beta and tyrosinated tubulins were easily detected on the apyrene and eupyrene axoneme; gamma tubulin was strongly marked on eupyrene axonemes but was scattered on the apyrene ones. Acetylated tubulin appeared with scattered labeling on the axoneme of both sperm types. Our results demonstrate significant differences in tubulin distribution in apyrene and eupyrene axonemal and cytoplasmic microtubules. Extracellular structures, especially the lacinate appendages, were not labeled by antibodies for any tubulin.     

SPECIALIZED APPENDAGES ON SPERMATIA FROM THE RED ALGA AGLAOTHAMNION NEGLECTUM (CERAMIALES,CERAMIACEAE) SPECIFICALLY BIND WITH TRICHOGYNES1

Spermatia from Aglaothamnion neglectum Feldmann-Mazoyer specifically bind with trichogynes and hairs of female thalli, One of the functions of hairs on female thalli appears to be the catching of spermatia. Fertilization can occur if a spermatium binds first with a hair and then binds with a trichogyne. The binding of spermatia with trichogynes is not species specific, but only occurs beween closely related species. Spermatia have fimbriate coneshaped appendages projecting from each end that are responsible for initial binding with trichogynes.     

Observations on the flagellar apparatus of a coccolithophorid,Cruciplacolithus neohelis (Prymnesiophyceae)

The flagellar apparatus ofCruciplacolithus neohelis (McIntyre and Bé) Reinhardt including its transition region is described. The transition region contains a hat-shaped structure, which is suggested to be one of the common features of the Prymnesiophyceae. Its flagellar root system resembles that of most coccolithophorids examined so far, except that only one vestigial crystalline root is present associated with root 1. Two well-developed crystalline roots associated with roots 1 and 2, respectively, appear in the preprophase of nuclear division, suggesting conversion to a mitotic spindle. The taxonomic and evolutionary significance of the flagellar apparatus is discussed.     

昆虫腹肢发育相关基因的研究进展

昆虫躯干外着生有一系列附属器官,主要包括背侧附器和腹侧附器,其中腹肢的多样性表现尤为突出。腹肢的发育过程受到多种调控因子的作用。本文就腹肢发育相关基因的表达、功能及调控因子间的相互作用等方面进行简要的综述。一方面,腹肢作为整体受Hox基因和成形素基因（Dpp/Wg）的调控,Hox基因直接决定腹肢的有无,Dpp/Wg通过其表达产物形成浓度梯度调控整个腹肢的发育,两者在腹肢整体发育中的作用不可取代。另一方面,腹肢基部、中部及远端部位分别受到各自特异的调控因子的作用。其中hth,tsh及al等均主要调节腹肢基部的发育,dac通过与Dll和Dpp/Wg相互作用从而调节腹肢中部的发育,bab,Dll及Lim1等对腹肢远端发育发挥重要作用。关节的形成对腹肢分节的形成至关重要,Notch信号通路相关因子如配体基因Dl和Ser,修饰物基因fng及下游靶基因odd,sob,drm和bowl等调节该过程。因此,研究昆虫腹肢发育相关基因,对于深入揭示腹肢的发育及其在进化过程中多样性形成的分子机制具有至关重要的作用。     

Biochemical Characterization of the Bi-lobe Reveals a Continuous Structural Network Linking the Bi-lobe to Other Single-copied Organelles in Trypanosoma brucei

Trypanosoma brucei, a unicellular parasite, contains several single-copied organelles that duplicate and segregate in a highly coordinated fashion during the cell cycle. In the procyclic stage, a bi-lobed structure is found adjacent to the single ER exit site and Golgi apparatus, forming both stable and dynamic association with other cytoskeletal components including the basal bodies that seed the flagellum and the flagellar pocket collar that is critical for flagellar pocket biogenesis. To further understand the bi-lobe and its association with adjacent organelles, we performed proteomic analyses on the immunoisolated bi-lobe complex. Candidate proteins were localized to the flagellar pocket, the basal bodies, a tripartite attachment complex linking the basal bodies to the kinetoplast, and a segment of microtubule quartet linking the flagellar pocket collar and bi-lobe to the basal bodies. These results supported an extensive connection among the single-copied organelles in T. brucei, a strategy employed by the parasite for orderly organelle assembly and inheritance during the cell cycle.     

The sperm structure of <Emphasis Type="Italic">Galloisiana yuasai</Emphasis> (Insecta,Grylloblattodea) and implications for the phylogenetic position of Grylloblattodea

The sperm ultrastructure of the Grylloblattodea Galloisiana yuasai was described and the sperm characters were comparatively examined in several orthopteroid insect orders for inferring the phylogenetic placement of the Grylloblattodea. The spermatozoa of G. yuasai are joined in bundles (spermatodesms) containing 200 units. Major features of these spermatozoa include a monolayered acrosome, a 9+9+2 axoneme with 16-pfs accessory microtubules and expanded intertubular material, and an evident “centriole adjunct”. The diffused material observed between the axoneme and the mitochondrial derivatives is considered to be an extension of the three connecting bands observed in other orthopteroid taxa, similar to what happens in some orthopteran lineages. The presence of the connecting bands, even though modified in G. yuasai, suggests that the Grylloblattodea are to be placed in a clade with Mantophasmatodea, Mantodea and Orthoptera.     

Comparative morphology among trunk limbs of Caenestheriella gifuensis and Leptestheria kawachiensis (Crustacea: Branchiopoda: Spinicaudata)

Morphological differences among groups of the 24 trunk limbs of Caenestheriella gifuensis (Ishikawa, 1895) and differences between males and females are described and illustrated. A setose attenuate lobe located proximally near enditic lobe 1 and a discoid lobe covered with small setae proximal to enditic lobe 1 are newly described. The five ventral enditic lobes, endopod, exopod, and dorsal exite of traditional spinicaudatan morphology are redescribed. Trunk limbs 1–4 of females bear a palp on enditic lobe 5 and trunk limbs 1–15 of males bear a similar palp. A second, articulating palp is associated with the base of the endopod of trunk limbs 1–2 of males. The proximal part of trunk limbs 19–24, bearing enditic lobe 1, articulates by an arthrodial membrane with the remainder of the limb, and the exite is distal to this arthrodial membrane. Development of trunk limbs, ascertained through an examination of early juvenile instars of Leptestheria kawachiensis Uéno, 1927, includes an asetose limb followed in time by a series of setose limbs that increase in morphological complexity with age. The number of lobes on the asetose limb varies from seven (corresponding to five enditic lobes, an endopod, and an exopod) on anterior limbs to five on trunk limb 24, which lacks the lobes corresponding to enditic lobe 4 and the endopod; these two structures are added later to setose limbs. The attenuate lobe, the discoid lobe, the exite of all trunk limbs, and the palps of the anterior trunk limbs are added to the setose limbs. Development of anterior limbs is accelerated relative to that of posterior limbs, and development of the more posterior limbs is truncated relative to that of limbs immediately anterior to them. Enditic lobe 4 and the endopod of limbs like trunk limb 24 develop from, or are patterned by, enditic lobe 5; the articulating palp of male trunk limbs 1–2 also may be added in this way. A comparison of these observations with development of the copepod maxilliped suggests that the spinicaudatan trunk limb is composed of a praecoxa with three lobes, a coxa and a basis each with one lobe, and an endopod of three segments in females and four in males. This is similar to the homology scheme previously proposed by Hansen in 1925. A critique is given of attempts to homologize parts of arthropod limbs based on developmental gene expression patterns. Stenopodal to phyllopodal transformations of maxillipeds in copepods provide a model at least partly applicable to spinicaudatans, and a ‘multibranched’ interpretation of spinicaudatan (and by extension branchiopodan) limb morphology is rejected. There is nothing intrinsic to the structure of the adult trunk limbs suggesting that they are similar to the adult limbs of the ancestral branchiopod or the ancestral crustacean, but early developmental steps of more posterior limbs are good matches for the morphology of an ancestral crustacean biramal limb predicted by a hypothesis of duplication of the proximo‐distal axis. © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society, 2003, 139 , 547–564. No claim to original US government works.     

Hair Follicle Development in Mouse Pluripotent Stem Cell-Derived Skin Organoids

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Comparative cytology and taxonomy of theUlvaphyceae II. Ulvalean characteristics of the stephanokont flagellar apparatus ofDerbesia tenuissima

Summary The stephanokont flagellar apparatus of the zoospores ofDerbesia tenuissima (De Not.) Crouan is examined and compared to the flagellar apparatuses of other green algae. The flagella ofDerbesia are attached to two of three bands which lie at the junction of the body and papilla. Serial longitudinal and cross sections reveal that the basal bodies are attached to the bands along their sides and at their proximal ends. The bands are not striated in any plane. The lack of striation in the bands and the partial covering of the proximal end of the basal bodies by one of the bands closely resemble the type of flagellar connection system described as the Bryopsis-type byMelkonian (1980). Zoospores of ulvalean green algae also possess these features, suggesting that green siphons are phylogenetically related to theUlvales. It is proposed that green siphons be tentatively classified in theUlvaphyceae rather than in theChlorophyceae orCharophyceae.This work supported by NSF Grant DEB 78-03554.