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Holland, LZ, Miller RL.  1994.  Mechanism of Internal Fertilization in Pegea-Socia (Tunicata, Thaliacea), a Salp with a Solid Oviduct. Journal of Morphology. 219:257-267.   10.1002/jmor.1052190305   AbstractWebsite

The ovary of the salp Pegea socia (Bose, 1802) is located at the end of an atrial diverticulum. The ovary consists of a single oocyte encased in a layer of follicle cells and is connected to the atrial epithelium by an oviduct. Transmission electron microscopy shows that the oocyte lacks a vitelline layer, cortical granules, and yolk granules and that the oviduct lacks a continuous lumen. What previous authors thought was a lumen is a line of dense intercellular junctions running down the center of the oviduct. The sperm nucleus in this species, as in other salps, is elongate. The tubular mitochondrion spirals about the sperm nucleus giving it a corkscrew-shape appearance. Sperm reach the ovary when the oocyte is still at the germinal vesicle stage. Many sperm swim up the atrial diverticulum and burrow through the cells of the atrial epithelium, oviduct, and follicular epithelium. Thus oviduct shortening, which occurs when the oocyte is in the meiotic divisions, is evidently unrelated to sperm moving up the oviduct. All previous authors, who argued either that a continuous lumen is necessary for sperm to move up the oviduct or that sperm bypass the oviduct, were incorrect. (C) 1994 Wiley-Liss, Inc.

Holland, PWH, Garcia-Fernandez J, Holland LZ, Williams NA, Holland ND.  1994.  The Molecular Control of Spatial Patterning in Amphioxus. Journal of the Marine Biological Association of the United Kingdom. 74:49-60. AbstractWebsite

The embryology of amphioxus (Chordata: Cephalochordata) has features in common with vertebrate embryology, reflecting a dose phylogenetic relationship between the two taxa. Amphioxus differs from vertebrates, however, in having less complex organogenesis and cranial morphogenesis, and less specialization along the anteroposterior body axis. Here we illustrate this by describing the embryology of an amphioxus species, Branchiostoma floridae. To gain further insight into the origins, evolutionary divergence and comparative embryology of these taxa, we are comparing the molecular control of embryonic development in amphioxus and vertebrates. For these analyses, we are focusing on homeobox genes: a diverse multigene family implicated in developmental control in many Metazoa. We report the results of PCR-based experiments which reveal that the amphioxus genome has homeobox genes from several recognized gene classes. The PCR experiments also suggest that amphioxus has fewer 'Hox' and 'Msx' class homeobox genes than do vertebrates. We suggest, therefore, that amphioxus may be a living descendant from an intermediate stage in the evolution of homeobox gene family complexity, and the complexity of vertebrate developmental control. The pattern of gene expression during embryogenesis has been described for one amphioxus homeobox gene of the Hox class. This gene is primarily expressed in the presumptive neural tube of amphioxus neurulae, later embryos and larvae, in a spatially-restricted manner. The expression data lead us to suggest that Hox genes are involved in the control of spatial patterning in the neural tube of amphioxus; the data are also interpreted as giving insight into possible homology between the amphioxus and vertebrate body plans.

Holland, ND, Holland LZ.  1993.  Serotonin-Containing Cells in the Nervous-System and Other Tissues During Ontogeny of a Lancelet, Branchiostoma-Floridae. Acta Zoologica. 74:195-204. AbstractWebsite

Serotonin-containing cells are described by immunohistochemistry throughout lancelet ontogeny. Such cells are first detected in the 2-day larva: these are (1) enterochromaffin cells in the inner epithelium of the gut and (2) anterior serotonergic neurons at the rostral end of the nerve cord. In the 6-day larva, relatively low levels of serotonin appear in ventro-lateral perikarya and cell processes of intraspinal serotonergic neurons scattered along the nerve cord. In the 18-day (early metamorphic) larva, antero-lateral serotonergic neurons are detected near the rostral end of the nerve cord as two small, bilateral clusters of perikarya with axons that descend the nerve cord; at later developmental stages, these axons extend almost to the posterior end of the body. In the 21-day (mid-metamorphic) larva, serotonin can no longer be detected in the anterior serotonergic neurons, but serotonin-containing cells are found subjacent to the inner epithelium of the digestive caecum and in the peribranchial epithelium covering the primary gill bars. In the discussion, we suggest that the anterior serotonergic neurons may play a role in larval photoreception and that the antero-lateral serotonergic neurons may be homologous to vertebrate hindbrain neurons with axons descending the spinal cord to modulate undulation (if this homology is valid, the anterior limit of the lancelet hindbrain would be roughly 100 mum behind the rostral tip of the nerve cord).

Holland, ND, Holland LZ.  1993.  Embryos and larvae of invertebrate deuterostomes. Essential developmental biology : a practical approach. ( Stern CD, Holland PWH, Eds.).:21-32., Oxford ; New York: IRL Press at Oxford University Press Abstract
Holland, PWH, Holland LZ, Williams NA, Holland ND.  1992.  An Amphioxus Homeobox Gene - Sequence Conservation, Spatial Expression During Development and Insights into Vertebrate Evolution. Development. 116:653-&. AbstractWebsite

The embryology of amphioxus has much in common with vertebrate embryology, reflecting a close phylogenetic relationship between the two groups. Amphioxus embryology is simpler in several key respects, however, including a lack of pronounced craniofacial morphogenesis. To gain an insight into the molecular changes that accompanied the evolution of vertebrate embryology, and into the relationship between the amphioxus and vertebrate body plans, we have undertaken the first molecular level investigation of amphioxus embryonic development. We report the cloning, complete DNA sequence determination, sequence analysis and expression analysis of an amphioxus homeobox gene, AmphiHox3, evolutionarily homologous to the third-most 3' paralogous group of mammalian Hox genes. Sequence comparison to a mammalian homologue, mouse Hox-2.7 (HoxB3), reveals several stretches of amino acid conservation within the deduced protein sequences. Whole mount in situ hybridization reveals localized expression of AmphiHox3 in the posterior mesoderm (but not in the somites), and region-specific expression in the dorsal nerve cord, of amphioxus neurulae, later embryos and larvae. The anterior limit to expression in the nerve cord is at the level of the four/five somite boundary at the neurula stage, and stabilises to just anterior to the first nerve cord pigment spot to form. Comparison to the anterior expression boundary of mouse Hox-2.7 (HoxB3) and related genes suggests that the vertebrate brain is homologous to an extensive region of the amphioxus nerve cord that contains the cerebral vesicle (a region at the extreme rostral tip) and extends posterior to somite four. This proposed homology implies that the vertebrate brain probably did not evolve solely from the cerebral vesicle of an amphioxus-like ancestor, nor did it arise entirely de novo anterior to the cerebral vesicle.

Holland, LZ, Holland ND.  1992.  Early Development in the Lancelet (= Amphioxus) Branchiostoma-Floridae from Sperm Entry through Pronuclear Fusion - Presence of Vegetal Pole Plasm and Lack of Conspicuous Ooplasmic Segregation. Biological Bulletin. 182:77-96.   10.2307/1542182   AbstractWebsite

Lancelet eggs are described from serial fine sections before fertilization and at frequent intervals thereafter until the male and female pronuclei meet at 16 min after insemination. In the unfertilized egg, although mitochondria, as well as yolk granules, are evenly distributed (both are absent only from the egg cortex and meiotic spindle), the mitochondria in the animal third have a more electron-lucent matrix than those elsewhere. The cortex of the unfertilized egg is occupied chiefly by cortical granules, and the subcortical cytoplasm in the vegetal third includes sheets of dense granules interleaved with cisternae of endoplasmic reticulum. By 45 s after insemination, (1) the fertilizing sperm enters (in the animal hemisphere in three out of three observations), (2) yolk granules become patchily distributed around the newly entered sperm, (3) cortical granule exocytosis occurs, and (4) the sheets of dense granules and associated endoplasmic reticulum aggregate with numerous mitochondria into whorls in a yolk-free zone near the vegetal pole. These whorls are the vegetal pole plasm, which is segregated into a single blastomere at each cleavage and might play a role in germ line determination. By 2 min after insemination, the zone of cytoplasm near the animal pole with patchily distributed yolk has enlarged, and the male pronucleus has migrated to the vicinity of the vegetal pole and formed an aster, at the center of which a few mitochondria are aggregated. In lancelets, unlike ascidians, there is no obvious widespread ooplasmic segregation or translocation of cytoplasm from animal to vegetal pole accompanying the movement of the sperm. Between 6 and 16 min, (1) the zone of cytoplasm with patchily distributed yolk enlarges to occupy about the animal third of the egg, (2) the female pronucleus forms by fusion of chromosome-containing vesicles and migrates vegetally, leaving a track of yolk-poor cytoplasm, and (3) the male pronucleus, surrounded by increasing numbers of mitochondria, migrates to meet the female pronucleus just above the equator. In contrast to current opinion, lancelets differ from ascidians both in having a vegetal pole plasm and in lacking marked ooplasmic segregation.

Holland, ND, Holland LZ.  1991.  The Fine-Structure of the Growth Stage Oocytes of a Lancelet (= Amphioxus), Branchiostoma-Lanceolatum. Invertebrate Reproduction & Development. 19:107-122.   10.1080/07924259.1991.9672164   AbstractWebsite

Oocytes of the European lancelet (Branchiostoma lanceolatum) were fixed for transmission electron microscopy at Banyuls (French Mediterranean) in mid spring, which is just before the spawning season. Special attention is given to the growth stage (= diplotene) oocytes and to their relations with non-germinal cells of the ovary. At the time of year studied, the ovaries contain both relatively small (7-57-mu-m) and relatively large (97-127-mu-m) oocytes, but none of medium-size. In addition to the usual cell organelles (like free ribosomes, mitochondria, and endoplasmic reticulum), the oocytes include a number of more specialized structures. Nuage is present throughout the growth stage, both adjacent to the nucleus and scattered elsewhere in the cytoplasm. Other specialized structures do not begin to appear until the oocytes attain a certain diameter. The following structures are first detected at the following oocyte diameters: cortical granules, always in close association with Golgi complexes (20-mu-m); vacuoles containing presumed precursors of the vitelline layer (30-mu-m); yolk granules (35-mu-m); and a central vacuole within the nucleolus (50-mu-m). The cytoplasm of the largest oocytes includes a few annulate lamellae and some very unusual striated fibers resembling ciliary rootlets. These fibers, which are banded with a 70-nm periodicity (but are evidently not associated with centrioles), occur only at the animal pole of the oocyte, and their functional significance is unknown. The smaller oocytes have relatively smooth plasma membranes, except where endocytotic pits are abundant, whereas the larger oocytes bear abundant microvilli and are covered by a vitelline layer of dense, granular material. During oocyte growth, areas of contact between the oocytes and neighboring non-germinal cells shrink progressively. In the large oocytes, such contacts are limited to the animal pole, where a few processes from non-germinal cells pass through the vitelline layer and terminate on the oocyte plasma membrane at adhaerens type junctions (perhaps mixed with gap junctions). The possible functions and phylogenetic significance of such junctions are discussed.

Holland, ND, Holland LZ.  1991.  The Histochemistry and Fine-Structure of the Nutritional Reserves in the Fin Rays of a Lancelet, Branchiostoma-Lanceolatum (Cephalochordata = Acrania). Acta Zoologica. 72:203-207. AbstractWebsite

Adults of the European lancelet were collected at Banyuls-sur-Mer (Mediterranean France) in mid-spring, shortly before the onset of the breeding season. The dorsal and ventral fin rays were studied by light microscopic histochemistry and by transmission electron microscopy (TEM). Each fin ray is a mass of extracellular material that accumulates beneath the mesothelium of a fin box coelom. The fin ray material is rich in lipids, proteins, and neutral mucopolysaccharides. TEM reveals no lipid droplets in this material. which consists entirely of a packed mass of 15-20 nm granules of medium electron density. It is likely that these granules consist of glycoproteins or glycolipoproteins. Our results are consistent with the proposal of Azariah (1965, Journal of the Marine Biological Association of India 7: 459-661 ) that lancelet fin rays are nutritional reserves supporting gametogenesis during the breeding season.

Holland, ND, Holland LZ, Davis CA, Honma Y.  1991.  Expression domains of engrailed gene in lamprey embryos. American Zoologist. 31:A46-A46. AbstractWebsite
Fujimura, Y, Titani K, Holland LZ, Roberts JR, Kostel P, Ruggeri ZM, Zimmerman TS.  1987.  A Heparin-Binding Domain of Human Vonwillebrand-Factor - Characterization and Localization to a Tryptic Fragment Extending from Amino-Acid Residue Val-449 to Lys-728. Journal of Biological Chemistry. 262:1734-1739.Website
Pareti, FI, Fujimura Y, Dent JA, Holland LZ, Zimmerman TS, Ruggeri ZM.  1986.  Isolation and Characterization of a Collagen Binding Domain in Human Vonwillebrand-Factor. Journal of Biological Chemistry. 261:5310-5315.Website
Fujimura, Y, Titani K, Holland LZ, Russell SR, Roberts JR, Elder JH, Ruggeri ZM, Zimmerman TS.  1986.  Vonwillebrand-Factor - a Reduced and Alkylated 52/48-Kda Fragment Beginning at Amino-Acid Residue-449 Contains the Domain Interacting with Platelet Glycoprotein Ib. Journal of Biological Chemistry. 261:381-385.Website
Fulcher, CA, Roberts JR, Holland LZ, Zimmerman TS.  1985.  Human Factor-Viii Procoagulant Protein - Monoclonal-Antibodies Define Precursor-Product Relationships and Functional Epitopes. Journal of Clinical Investigation. 76:117-124.   10.1172/jci111933   Website
Cross, NL, Slezynger TC, Holland LZ.  1985.  Isolation and Partial Characterization of Urechis-Caupo Egg Envelopes. Journal of Cell Science. 74:193-205.Website