RESUMEN
Despite its international image as a sexually free-spirited country, local attitudes toward morality of sexual behavior remain complex throughout Brazil, especially in rural areas and the conservative Northeast region. In addition, notwithstanding its official ideology of nonracism, African ancestry as judged through personal appearance (color) constitutes a significant social and economic disadvantage. Using Goffman's idea of "spoiled identity" as a starting point, I show how locals use sexual behavior as a multivocal symbol of moral status in women, and how spoiled sexual reputation interacts with other stigmatized statuses, especially color. I also consider how the acquisition of sexually stigmatized status jeopardizes women's well-being and that of their children.
Asunto(s)
Prejuicio , Grupos Raciales , Sexualidad , Adulto , Brasil/etnología , Relaciones Extramatrimoniales , Femenino , Identidad de Género , Humanos , Masculino , Principios Morales , Opinión Pública , Población RuralRESUMEN
Patterns of alcohol use are affected by culture and history and interwined with the rhythms of work life. The 20th century economic shift toward industrial and service jobs coupled with the increasing presence of women in the workplace has revolutionized U.S. women's domestic and public roles [1], and these changes have impacted their drinking behavior [2]. In addition, in a multicultural society like the United States, subcultures, ethnic groups, socioeconomic classes, and even job categories have their own sets of gendered drinking norms. patterns of alcohol use among women can be better understood with consideration of intricate interactions among gender, ethnicity, class, employment, and alcohol consumption. Stepping up to the need to learn more about these factors, we have reviewed literature about ethnic, class, occupational, and gender influences on women's workplace-related drinking. This report on that review will show both the complexity of the phenomenon and the inconsistent, incomplete nature of existing information, as well as pointing out directions for future research. We begin with a general discussion of women and workplace drinking.
Asunto(s)
Alcoholismo/etnología , Alcoholismo/psicología , Diversidad Cultural , Empleo/psicología , Enfermedades Profesionales/etnología , Enfermedades Profesionales/psicología , Mujeres Trabajadoras/psicología , Femenino , Humanos , Modelos Psicológicos , Cultura Organizacional , Prevalencia , Factores de Riesgo , Factores Socioeconómicos , Estados Unidos/epidemiologíaRESUMEN
Centrosomes are unique cytoplasmic structures which serve as microtubule organizing centers (MTOC). In most animal cells centrosomes consist of one or more pair of centrioles surrounded by electron dense amorphous pericentriolar material (PCM) responsible for nucleation of microtubules. In the present study we analyzed the pattern of induction and localization of proteins of the PCM at different stages of neuronal development in cell cultures prepared from the embryonic hippocampus. For this purpose we used a human polyclonal antibody that recognizes two proteins of the PCM (100 kd and 60 kd, respectively). The results indicate that in mature neurons, pericentriolar immunoreactive material is preferentially localized in dendritic processes, and that throughout the course of neurite development and differentiation it is systematically excluded from the neuron's axon. Western blot analysis showed that during neuronal development in situ, there is an increase in the immunoreactivity for both proteins recognized by this antibody. In contrast, in hippocampal pyramidal neurons that develop in culture, there is an increase in the 60 kd polypeptide, while the 100 kd one is not detected after 7 days in vitro.
Asunto(s)
Centriolos/química , Dendritas/química , Hipocampo/citología , Neuronas/química , Tractos Piramidales/citología , Animales , Anticuerpos/análisis , Anticuerpos/inmunología , Western Blotting , Diferenciación Celular/fisiología , Células Cultivadas , Centriolos/inmunología , Centriolos/ultraestructura , Dendritas/ultraestructura , Electroforesis en Gel de Poliacrilamida , Embrión de Mamíferos/química , Embrión de Mamíferos/citología , Hipocampo/química , Hipocampo/embriología , Inmunohistoquímica , Microtúbulos/química , Microtúbulos/ultraestructura , Neuroblastoma/química , Neuroblastoma/patología , Neuroblastoma/ultraestructura , Neuronas/ultraestructura , Tractos Piramidales/química , Tractos Piramidales/ultraestructura , Ratas , Células Tumorales CultivadasRESUMEN
Class III beta-tubulin, isolated from adult bovine brain, is resolved into at least seven charge variants on isoelectric focusing gels. To identify the posttranslational modifications responsible for this heterogeneity, a mixture of brain tubulins was treated with cyanogen bromide and the C-terminal fragments from the class III beta-tubulin isoforms were then isolated by binding them to the monoclonal antibody TuJ1. Combined use of tandem mass spectrometry and both subtractive and automated Edman degradation chemistry on the isolated peptides indicates that many of the isoforms differ by phosphorylation at Ser-444 plus attachment of one to six glutamic acid molecules to the side chain of the first glutamate residue, Glu-438, in the C-terminal sequence Tyr-Glu-Asp-Asp-Glu-Glu-Glu-Ser-glu-Ala-Gln-Gly-Pro-Lys.
Asunto(s)
Encéfalo/fisiología , Neuronas/fisiología , Procesamiento Proteico-Postraduccional , Tubulina (Proteína)/genética , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales , Autoanálisis , Bovinos , Bromuro de Cianógeno , Espectrometría de Masas/métodos , Datos de Secuencia Molecular , Fragmentos de Péptidos/análisis , Tubulina (Proteína)/químicaRESUMEN
Mitotic spindles isolated from sea urchin eggs can be reactivated to undergo mitotic processes in vitro. Spindles incubated in reactivation media containing sea urchin tubulin and nucleotides undergo pole-pole elongation similar to that observed in living cells during anaphase-B. The in vitro behavior of spindles isolated during metaphase and anaphase are compared. Both metaphase and anaphase spindles undergo pole-pole elongation with similar rates, but only in the presence of added tubulin. In contrast, metaphase but not anaphase spindles increase chromosome-pole distance in the presence of exogenous tubulin, suggesting that in vitro, tubulin can be incorporated at the kinetochores of metaphase but not anaphase chromosomes. The rate of spindle elongation, ultimate length achieved, and the increase in chromosome-pole distance for isolated metaphase spindles is related to the concentration of available tubulin. Pole-pole elongation and chromosome-pole elongation does not require added adenosine triphosphate (ATP). Guanosine triphosphate (GTP) will support all activities observed. Thus, the force generation mechanism for anaphase-B in isolated sea urchin spindles is independent of added ATP, but dependent on the availability of tubulin. These results support the hypothesis that the mechanism of force generation for anaphase-B is linked to the incorporation of tubulin into the mitotic apparatus. (If, in addition, a microtubule-dependent motor-protein(s) is acting to generate force, it does not appear to be dependent on ATP as the exclusive energy source.
Asunto(s)
Anafase/fisiología , Metafase/fisiología , Huso Acromático/metabolismo , Tubulina (Proteína)/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Birrefringencia , Cromosomas/fisiología , Guanosina Trifosfato/metabolismo , Microscopía de Polarización , Óvulo , Erizos de Mar , Factores de TiempoRESUMEN
The charge heterogeneity of class III beta-tubulin (beta III) during neural development was analyzed by high-resolution isoelectric focusing/two-dimensional polyacrylamide gel electrophoresis in combination with site-specific proteolytic digestion and immunological detection. The number of beta III isoforms (charge variants) gradually increases from one in embryonic brain to seven in adult brain. All of the charge heterogeneity is due to posttranslationally modified sites located within the extreme C-terminal region of the beta III polypeptide. One beta III isoform is present in testis, the only other tissue in which this isotype is expressed. The testis beta III isoform cofocuses with the earliest-appearing embryonic brain beta III charge variant. Our results indicate that the posttranslational modifications of beta III are developmentally regulated, occur at more than one site, and are neuron-specific. The location of these modifications within the extreme C-terminal domain suggests that their function is to modulate the interaction of tubulin with microtubule-associated proteins.
Asunto(s)
Encéfalo/crecimiento & desarrollo , Procesamiento Proteico-Postraduccional , Tubulina (Proteína)/genética , Envejecimiento , Animales , Anticuerpos Monoclonales , Encéfalo/embriología , Encéfalo/metabolismo , Electroforesis en Gel de Poliacrilamida , Edad Gestacional , Sustancias Macromoleculares , Masculino , Proteínas de Microtúbulos/genética , Proteínas de Microtúbulos/aislamiento & purificación , Mapeo Peptídico , Ratas , Testículo/metabolismo , Tubulina (Proteína)/aislamiento & purificaciónRESUMEN
Inhibition of cAMP-dependent protein kinase activity by microinjection of a specific physiologic protein inhibitor into sea urchin eggs inhibits the first cleavage after fertilization. Inhibition apparently occurs at some time prior to or during formation of the mitotic spindle. Measurement of the total protein kinase activity of sea urchin egg homogenates after fertilization showed that cAMP-dependent phosphorylation increases after fertilization and then declines prior to or at the time of the first cleavage. It is concluded that a cAMP-dependent phosphorylation plays a significant role in events leading to regulation of mitotic spindle assembly.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Mitosis/efectos de los fármacos , Óvulo/efectos de los fármacos , Inhibidores de Proteínas Quinasas , Cigoto/efectos de los fármacos , Animales , Fertilización/fisiología , Microinyecciones , Mitosis/fisiología , Óvulo/metabolismo , Óvulo/fisiología , Erizos de Mar , Cigoto/metabolismo , Cigoto/fisiologíaRESUMEN
The expression of a unique beta-tubulin isoform (class III) was monitored in squamous cell carcinoma (SCC) and normal epithelial cells using a monoclonal tubulin antibody called TuJ1. Whole tissue homogenates of SCC, normal tissue, SCC grown in nude mice, and SCC cultured cells were examined using sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot. TuJ1 antibody localization was performed using peroxidase immunostaining on paraffin sections of SCC, normal tissue, nude mouse SCC, and immunofluorescent microscopy of SCC cultured cells. The malignant tissues examined stained positive with TuJ1 and a general beta-tubulin antibody, whereas the normal tissues stained positively only for the general beta-tubulin antibody. TuJ1 epitope expression may be a useful marker for SCCs and may assist in understanding differences between normal and malignant squamous cells.
Asunto(s)
Biomarcadores de Tumor/inmunología , Carcinoma de Células Escamosas/inmunología , Epítopos/inmunología , Tubulina (Proteína)/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Western Blotting , Electroforesis en Gel de Poliacrilamida , Epitelio/inmunología , Técnica del Anticuerpo Fluorescente , Técnicas para Inmunoenzimas , Técnicas In Vitro , Ratones , Ratones Desnudos , Células Tumorales CultivadasRESUMEN
Five beta-tubulin isotypes are expressed differentially during chicken brain development. One of these isotypes is encoded by the gene c beta 4 and has been assigned to an isotypic family designated as Class III (beta III). In the nervous system of higher vertebrates, beta III is synthesized exclusively by neurons. A beta III-specific monoclonal antibody was used to determine when during chick embryogenesis c beta 4 is expressed, the cellular localization of beta III, and the number of charge variants (isoforms) into which beta III can be resolved by isoelectric focusing. On Western blots, beta III is first detectable at stages 12-13. Thereafter, the relative abundance of beta III in brain increases steadily, apparently in conjunction with the rate of neural differentiation. The isotype was not detectable in non-neural tissue extracts from older embryos (days 10-14) and hatchlings. Western blots of protein separated by two-dimensional gel electrophoresis (2D-PAGE) reveal that the number of beta III isoforms increases from one to three during neural development. This evidence indicates that beta III is a substrate for developmentally regulated, multiple-site posttranslational modification. Immunocytochemical studies reveal that while c beta 4 expression is restricted predominantly to the nervous system, it is transiently expressed in some embryonic structures. More importantly, in the nervous system, immunoreactive cells were located primarily in the non-proliferative marginal zone of the neural epithelia. Regions containing primarily mitotic neuroblasts were virtually unstained. This localization pattern indicates that c beta 4 expression occurs either during or immediately following terminal mitosis, and suggests that beta III may have a unique role during early neuronal differentiation and neurite outgrowth.
Asunto(s)
Embrión de Pollo/metabolismo , Neuronas/metabolismo , Tubulina (Proteína)/metabolismo , Animales , Anticuerpos Monoclonales , Especificidad de Anticuerpos , Inmunohistoquímica , Sistema Nervioso/embriología , Sistema Nervioso/metabolismo , Especificidad de Órganos , Procesamiento Proteico-Postraduccional , Tubulina (Proteína)/biosíntesisRESUMEN
Nuclei isolated from oocytes of the surf clam Spisula solidissima are disassembled when exposed to extracts from maturing oocytes. In the course of this process the nuclear lamina undergoes a marked reduction in size and the nuclear membrane appears to be fragmented into vesicles. These events are accompanied by extensive phosphorylation of the oocyte 67-kDa lamin and its solubilization. The changes observed are similar to those which occur in vivo in activated Spisula oocytes. Nuclear envelope breakdown in vitro requires ATP and Mg2+, but not Ca2+. It is not affected by protease inhibitors and is inhibited by alkaline phosphatase.
Asunto(s)
Bivalvos/ultraestructura , Membrana Nuclear/fisiología , Oocitos/ultraestructura , Adenosina Trifosfato/farmacología , Fosfatasa Alcalina/farmacología , Animales , Sistema Libre de Células , Cromatografía en Gel , Laminas , Magnesio/farmacología , Peso Molecular , Membrana Nuclear/efectos de los fármacos , Membrana Nuclear/ultraestructura , Proteínas Nucleares/metabolismo , Octoxinol , Fosforilación , Polietilenglicoles/farmacología , Inhibidores de Proteasas/farmacologíaRESUMEN
Current theories of fatalism and neglect and current descriptions of childhood illness in impoverished Northeastern Brazil are evaluated. Findings of an ongoing multidisciplinary project indicate that neglect and fatalism theories are incomplete as applied to the Brazilian Northeast. Intensive interviews and observations with bereaved mothers and traditional healers show that mothers' failure to obtain medical care for severely ill children is due more to real-life bureaucratic and geographic barriers to access than to fatalistic or neglectful attitudes on the part of the poor, that mothers' flat affect in response to infant deaths is due more to folk Catholic beliefs than to lack of emotional attachment to infants, that fatalistic statements are often post hoc and do not indicate fatalistic behavior, and that decisions about whether to treat severely ill infants are made by mothers and families in consultation with traditional healers in accord with a folk system of classification of high risk infants. What have been described as "death accepting," "pathogenic," and "ethnoeugenic" attitudes are part of a folk ethical system developed to guide reactions to terminal childhood illness. We argue that human behavior, especially in the realm of health, cannot be understood without reference to both biomedical and psychosocial realities.
Asunto(s)
Maltrato a los Niños/psicología , Características Culturales , Cultura , Madres/psicología , Adulto , Brasil , Ética Médica , Femenino , Desamparo Adquirido/psicología , Humanos , Lactante , Mortalidad Infantil , Medicina Tradicional , Persona de Mediana Edad , Aceptación de la Atención de Salud , Religión y Medicina , Factores SocioeconómicosRESUMEN
Problems in the control of access to and administration of oral rehydration therapy (ORT) in Northeast Brazil are described and discussed. Administration of ORT is controlled by the medical establishment, which is in general opposed to the use of home made and home administered ORT. Reasons for this resistance are discussed in terms of anthropological theories on ritual, mystification, and the social construction of reality; the medical establishment is described as using ORT as a symbol and guarantor of social status and power. Finally, an innovative program to circumvent the medical establishment by teaching ORT to traditional healers is described; the healers' integration of ORT into religious healing ceremonies is analyzed.
Asunto(s)
Características Culturales , Cultura , Diarrea Infantil/terapia , Diarrea/terapia , Fluidoterapia/psicología , Medicina Tradicional , Brasil , Niño , Preescolar , Diarrea/psicología , Diarrea Infantil/psicología , Femenino , Educación en Salud , Humanos , Lactante , Recién Nacido , Magia , Masculino , Rol del EnfermoRESUMEN
Spindles may be isolated from sea urchin eggs so that some mitotic processes can be reactivated in vitro. The isolation media allow spindles to remain stable for days. Transfer of the spindles to reactivation media results in loss of birefringence and breakdown of the matrix within which the microtubules function. If, however, tubulin and either guanosine triphosphate or adenosine triphosphate are present in these media so that tubulin can cycle, the spindles do not break down but grow in size and birefringence and show some of the movements of in vivo spindles. The most prominent is that of anaphase B if the mitotic apparatuses (MAs) have been isolated at a time when anaphase was initiated. When isolated during metaphase, MAs either do not show chromosome movement or, if they do, it is a random movement which causes redistribution of the chromosomes on the spindle surface. In either case, such metaphase spindles grow in size and birefringence. Thus under the proper conditions, cycling microtubules can interact with the spindle matrix to induce chromosome movements which resemble those seen in in vivo cells in the case of anaphase B and show some aspects of anaphase A in at least half the spindles isolated at metaphase, although such movements are not coordinated to show a true anaphase movement.
Asunto(s)
Erizos de Mar/citología , Adenosina Trifosfato/farmacología , Anafase , Animales , Birrefringencia , Cromosomas , Guanosina Trifosfato/farmacología , Erizos de Mar/genética , Huso Acromático , Tubulina (Proteína)/aislamiento & purificación , Grabación en VideoRESUMEN
The crude actomyosin precipitate from sea urchin (Arbacia punctulata) egg extracts contains Ca2+-sensitive myosin light chain kinase activity. Activity can be further increased by exogenous calmodulin (CaM). Egg myosin light chain kinase activity is purified from total egg extract by fractionating on three different chromatographic columns: DEAE ion exchange, gel filtration on Sephacryl-300, and Affi-Gel-CaM affinity. The purified egg kinase depends totally on Ca2+ and CaM for activity. Unphosphorylated egg myosin has very little actin-activated ATPase. After phosphorylation of the phosphorylable light chain by either egg kinase or gizzard myosin light chain kinase, the actin-activated ATPase of egg myosin is enhanced several fold. However, the egg kinase bears some unique characteristics which are very different from conventional myosin light chain kinases of differentiated tissues. The purified egg kinase has a native molecular mass of 405 kDa, while on sodium dodecyl sulfate-polyacrylamide electrophoresis it shows a single subunit of 56 kDa. The affinity of egg kinase for CaM (Ka = 0.4 microM) is relatively weaker than that of the gizzard myosin light chain kinase. The egg kinase autophosphorylates in the presence of Ca2+ and CaM and has a rather broad substrate specificity. The possible relationship between this egg Ca2+-CaM-dependent kinase and the Ca2+-CaM-dependent kinases from brain and liver is discussed.
Asunto(s)
Calcio/metabolismo , Calmodulina/metabolismo , Óvulo/enzimología , Proteínas Quinasas/metabolismo , Actomiosina/metabolismo , Adenosina Trifosfatasas/metabolismo , Animales , Cromatografía de Afinidad , Cromatografía en Gel , Cromatografía por Intercambio Iónico , Molleja No Aviar/enzimología , Cinética , Quinasa de Cadena Ligera de Miosina , Miosinas/metabolismo , Fosforilación , Erizos de Mar , Especificidad por SustratoAsunto(s)
Encéfalo/citología , Proteínas Asociadas a Microtúbulos/análisis , Microtúbulos/ultraestructura , Proteínas del Tejido Nervioso/análisis , Neuronas/citología , Envejecimiento , Animales , Encéfalo/crecimiento & desarrollo , Bovinos , Núcleo Caudado/citología , Cerebelo/citología , Corteza Cerebral/citología , Ensayo de Inmunoadsorción Enzimática , Microscopía Electrónica , Peso Molecular , Células de Purkinje/citología , Ratas , Proteínas tauRESUMEN
We have presented data that indicate that MAP-2 associates with brain microtubules at nonrandomly distributed sites, whose distribution on the microtubule polymer can best be described by the 12-dimer MAP superlattice originally described by Amos; because of the additional spacings, however, between MAP-2 projections observed on MAP-2-saturated microtubules, we suggest that the 6-dimer MAP superlattice, or what we will call the double Amos superlattice, more completely specifies the total set of MAP-binding sites on cytoplasmic microtubules. Second, we have shown that brain microtubules reassembled in vitro contain a heterogeneous population of MAP-binding sites, which differ in their affinities for the two MAPs, MAP-2 and tau. Third, we have shown that microtubule populations that differ in their MAP content have subtle, but detectable differences in their tubulin isotype composition. Based on all the data presented here, we have presented the idea of a nonrandom distribution of tubulin isotypes within a microtubule as a means by which a cell could specify both the identity and the distribution of MAP-binding sites.
Asunto(s)
Encéfalo/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Microtúbulos/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Animales , Encéfalo/ultraestructura , Bovinos , Electroforesis en Gel de Poliacrilamida , Sustancias Macromoleculares , Microscopía Electrónica , Proteínas Asociadas a Microtúbulos/aislamiento & purificación , Microtúbulos/ultraestructura , Modelos Moleculares , Unión Proteica , Conformación Proteica , Proteínas tauAsunto(s)
Encéfalo/metabolismo , Calcio/farmacología , Calmodulina/farmacología , Proteínas Asociadas a Microtúbulos/metabolismo , Microtúbulos/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Animales , Encéfalo/ultraestructura , Bovinos , Electroforesis en Gel de Poliacrilamida , Cinética , Sustancias Macromoleculares , Proteínas Asociadas a Microtúbulos/aislamiento & purificación , Microtúbulos/efectos de los fármacos , Microtúbulos/ultraestructura , Peso Molecular , Tubulina (Proteína)/metabolismo , Proteínas tauRESUMEN
We have determined the biochemical and immunocytochemical localization of the heterogeneous microtubule-associated protein tau using a monoclonal antibody that binds to all of the tau polypeptides in both bovine and rat brain. Using immunoblot assays and competitive enzyme-linked immunosorbent assays, we have shown tau to be more abundant in bovine white matter extracts and microtubules than in extracts and microtubules from an enriched gray matter region of the brain. On a per mole basis, twice-cycled microtubules from white matter contained three times more tau than did twice-cycled microtubules from gray matter. Immunohistochemical studies that compared the localization of tau with that of MAP2 and tubulin demonstrated that tau was restricted to axons, extending the results of the biochemical studies. Tau localization was not observed in glia, which indicated that, at least in brain, tau is neuron specific. These observations indicate that tau may help define a subpopulation of microtubules that is restricted to axons. Furthermore, the monoclonal antibody described in this report should prove very useful to investigators studying axonal sprouting and growth because it is an exclusive axonal marker.
Asunto(s)
Química Encefálica , Proteínas Asociadas a Microtúbulos/análisis , Proteínas del Tejido Nervioso/análisis , Animales , Anticuerpos Monoclonales/inmunología , Axones/análisis , Bovinos , Técnicas Inmunológicas , Ratones , Ratones Endogámicos BALB C , Proteínas Asociadas a Microtúbulos/inmunología , Microtúbulos/análisis , Proteínas del Tejido Nervioso/inmunología , Neuroglía/análisis , Ratas , Tubulina (Proteína)/análisis , Proteínas tauRESUMEN
A burst of endocytosis accompanying microvillar elongation follows cortical granule exocytosis in normal sea urchin development. By 5 min postfertilization the burst is over and a lower level of endocytosis ensues (constitutive phase). To determine whether microvillar elongation and initiation of endocytosis are necessary concommitants of cortical granule exocytosis we utilized Chase's (1967, Ph.D. thesis, University of Washington, Seattle) high-hydrostatic pressure technique to block the latter and then examined developing eggs for endocytosis and microvillar elongation. To accomplish this, eggs were fertilized, after which hydrostatic pressure was quickly raised to 6000-7000 psi at the start of cortical granule exocytosis and maintained for 5 min. Only the cortical granules immediately surrounding the sperm penetration site were secreted (about 3% or less of the egg's total number of cortical granules). Blockage of major cortical granule exocytosis had the following consequences on surface events during first division: (1) The endocytosis burst normally associated with cortical granule exocytosis was effectively eliminated as was early microvillar elongation and elevation. Both occurred to a limited extent around the sperm penetration site which resulted in a highly localized surface transformation. (2) By 20 min after fertilization endocytosis began over the rest of the egg surface in the absence of any further cortical granule exocytosis. (3) Subsequently, during a 30-min period starting midway between fertilization and first cleavage microvilli more than doubled in length and endocytosis levels increased severalfold. These events brought about a complete surface transformation similar to that which normally occurs in early development but in the absence of cortical granule exocytosis. By first cleavage surfaces and cortices of high-pressure-treated and control eggs were nearly indistinguishable except for the presence of cortical granules in cortices of the former. Pressure-treated eggs cleaved normally and developed to larval forms overnight. The period of late surface transformation in high-pressure-treated Strongylocentrotus purpuratus eggs corresponds in timing and some of its characteristics to second phase microvillar elongation observed in normal development in this species and also in S. droebachiensis development. These observations suggest, therefore, that microvillar elongation and endocytosis are necessary membrane remodelling events which must occur for normal development even in the absence of membrane addition from the cortical granules.