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Early to Middle Miocene sea-level oscillations of approximately 40–60 m estimated from far-field records1–3are interpreted to reflect the loss of virtually all East Antarctic ice during peak warmth2. This contrasts with ice-sheet model experiments suggesting most terrestrial ice in East Antarctica was retained even during the warmest intervals of the Middle Miocene4,5. Data and model outputs can be reconciled if a large West Antarctic Ice Sheet (WAIS) existed and expanded across most of the outer continental shelf during the Early Miocene, accounting for maximum ice-sheet volumes. Here we provide the earliest geological evidence proving large WAIS expansions occurred during the Early Miocene (~17.72–17.40 Ma). Geochemical and petrographic data show glacimarine sediments recovered at International Ocean Discovery Program (IODP) Site U1521 in the central Ross Sea derive from West Antarctica, requiring the presence of a WAIS covering most of the Ross Sea continental shelf. Seismic, lithological and palynological data reveal the intermittent proximity of grounded ice to Site U1521. The erosion rate calculated from this sediment package greatly exceeds the long-term mean, implying rapid erosion of West Antarctica. This interval therefore captures a key step in the genesis of a marine-based WAIS and a tipping point in Antarctic ice-sheet evolution.

Despite the common association of human lice with abandoned or neglected people, no procedure to assess pediculosis, aimed to detect signs of neglect, exists. Investigating the two most common forms of head louse infestation, regular and severe, we define lice-markers of neglect and develop a protocol and survey form to record and assess pediculosis. The study of head lice from a deceased victim of neglect helped unravel time-length since death, frequency of exposure to neglect and the cause and circumstances related to the death. Nit-clusters are markers of neglect, indicating length and frequency of neglect episodes. In the case study used here that culminated in the death of the victim, sustained abandonment started circa 2 years before discovery. The lice suggested that death was caused by overconsumption of a powerful calcium channel blocker, an antihypertensive, an excess of which in lice food supply (blood) stops oogenesis. Despite hosting thousands of adult females on the hair, lice reproduction stopped and nits were no longer developed or deposited on the hairs at the root end. This short distance of the shaft with no nits provided a time estimation of overdosing of almost 2 months before death. [ABSTRACT FROM AUTHOR]

En individuos con Enfermedad Renal Crónica (ERC), altas ingestas de fósforo (P) dietario pueden promover la calcificación vascular y eventos cardiovasculares, incrementando el riesgo de mortalidad. Una de las estrategias habitualmente utilizadas para controlar los niveles de P sérico consiste en la restricción del P dietario. Sin embargo, debido a la estrecha relación entre los niveles de P y proteínas que existe en los alimentos naturales, se dificulta el diseño de dietas que contemplen bajos niveles de P sin comprometer la ingesta adecuada de proteínas. De este modo, para asegurar una provisión adecuada de proteínas asociada con el más bajo contenido de P posible, es útil estimar la relación P (mg)/proteína (g) de los alimentos. Las guías K/DOQI (Kidney Disease Outcomes Quality Initiative) recomiendan una ingesta diaria de 10-12 mg de P/g de proteína, lo cual corresponde en promedio para una persona de unos 70 kg, un consumo diario de 84 g de proteínas y a una ingesta máxima de 1000 mg de P. En general, alimentos naturales ricos en proteínas tales como carnes, lácteos, huevos y cereales aportan principalmente formas orgánicas del P, las cuales presentan una absorción en torno al 50%. En un gran número de alimentos procesados se suman al P naturaímente presente, compuestos inorgánicos que cumplen la función de aditivos alimentarios. El P inorgánico se presenta en forma de sales fácilmente disociadas que presentan una absorción entre el 90% y el 100%. De este modo, los aditivos fosfóricos tienen un mayor impacto en la hiperfosfatemia que las formas orgánicas del P y su empleo en el procesamiento de alimentos se ha incrementado notablemente en los últimos años. La estimación del contenido de P se hace dificultosa para quienes deben formular dietas para pacientes con ERC por dos razones principales: la legislación no obliga a las empresas a indicar en el rotulado de los productos el contenido de P, y en las tablas de composición de alimentos no se suelen incluir a los alimentos procesados. En este sentido, identificar en los rótulos de los productos la presencia de aditivos fosfóricos es un primer paso en la selección de alimentos que podrían incluirse en una dieta para pacientes con problemas renales. Teniendo en cuenta este panorama, se realizó un relevamiento de los rótulos de 238 alimentos de los grupos lácteos, carnes y cereales, y sus correspondientes productos derivados, comercializados en la ciudad de Santa Fe, a los efectos de conocer la situación real respecto al uso de aditivos fosfóricos por parte de la industria alimentaria. [ABSTRACT FROM AUTHOR]

Time-lapse cinematography revealed that activated human immunodeficiency virus (HIV)-infected monocytes crawl along surfaces, putting forward a leading pseudopod. Scanning electron micrographs showed monocyte pseudopods associated with spherical structures the size of HIV virions, and transmission electron micrographs revealed HIV virions budding from pseudopods. Filamentous actin (F-actin) was localized by electron microscopy in the pseudopod by heavy meromyosin decoration. Colocalization of F-actin and p24 viral antigen by light microscopy immunofluorescence indicated that F-actin and virus were present on the same pseudopod. These observations indicate that monocytes produce virus from a leading pseudopod. We suggest that HIV secretion at the leading edges of donor monocytes/macrophages may be an efficient way for HIV to infect target cells.

A morphological analysis was carried out on testicular biopsies of men with obstructive azoospermia as consequence of vas deferens malformations as compared with biopsies from fertile men. For each case the biopsies were processed with two different techniques: routine histological procedure, and semithin sections of specimens processed for electron microscopy. Four parameters were considered: (a) tubular morphology, (b) testicular biopsy score count (TBSC), (c) tubular diameter, and (d) germinal cell density. The data were quantified and analyzed by statistical tests. The biopsies of azoospermic men present a higher frequency of tubular sections with "tubular blockage," "sloughing" and cellular degeneration, lower values of TBSC, and lower germinal cell density. The results appear to be of relevant interest in relation to the existence of long-term testicular alteration following vasectomy.

After the addition of human T-cell lymphotropic virus type I (HTLV-I)-infected lymphocytes to enterocyte monolayers, the lymphocytes adhered via microvilli from both cell types and shed virus onto the enterocyte surface. Virus fused with the epithelial membrane and infected these cells as confirmed by electron microscopic immunocytochemistry, in situ hybridization, and amplification by polymerase chain reaction.

Human Anatomy, University of Milano, Milano, Italy We have treated sea urchin gametes with quercetin to investigate the effects of this drug on fertilization and egg activation. High concentrations of this drug gradually inhibited sperm motility, but pretreatment of sperm with the drug did not affect their fertility. Treatment of eggs with quercetin at micromolar concentrations completely blocked fertilization. The drug did not block the acrosome reaction of sperm, nor did it affect the binding of the acrosomal filament to the vitelline layer of the egg. However, fertilization was prevented. Inseminated quercetin-treated eggs could be activated by ionophore A23187, but still failed to incorporate sperm. Quercetin blocked fertilization if added after primary gamete binding, but 30 s before the beginning of the cortical reaction in experiments in which eggs were inseminated at low temperature. Drug added 10 s before the beginning of the cortical reaction was ineffective. Electron microscopy confirmed normal primary gamete binding and failure of fertilization. Vitelline layer removal by trypsin did not restore fertilizability to quercetin-treated eggs. Thus quercetin prevented fertilization by blocking gamete membrane fusion. These results indicate that quercetin can be a useful probe for the mechanism of membrane fusion in fertilization.

Events following the binding of Concanavalin A and cationized ferritin to the surface of normal human peripheral blood lymphocytes were followed using ultracytochemical methods. In this paper, we described a technique involving microdensitometry, which was employed in order to make a comparative cytochemical quantitation of the dense horseradish peroxidase-diaminobenzidine reaction products representing the states of Concanavalin A receptors under various conditions of distribution and redistribution. The technique presents a direct approach to the analysis of various probes that are currently being employed for studying the nature and distribution of various cell surface components. An attempt was also made to analyze the distribution of anionic sites, and their lateral redistribution is compared with the mobility of Concanavalin A receptors. The data presented suggests an independent mobility of receptors for Concanavalin A and cationized ferritin.

The rate constant (k) of the cytochrome oxidase reaction under optimal conditions for cytochemical staining (i.e., 15 min fixation, incubation for 180 min for heart, 120 min for pancreas) can be used as a measure of the enzyme concentration within mitochondria. The rate constant derived from microdensitometric measurements of the mass thickness of the 3,3'-diaminobenzidine (DAB) cytochrome oxidase reaction in cristae times correlated data derived from morphometry on the surface density of cristae (SVcristae/Vmit micron-1) and the volume density of mitochondria per cell (Vmit/Vcell) has been used to determine the respiratory index (RI) of these tissues according to the following equation: RI = k(SVcristae/Vcell). Using this formula, the RI of cardiac muscle tissue was computed to be 33 times the RI of pancreas under the conditions of our experiments. The greater cristae surface density and the large mitochondrial volume density in cardiac muscle and high k value accounted for the higher RI of cardiac muscle.

Cytochrome oxidase activity via cytochrome c, as demonstrated by the diaminobenzidine procedure, has been employed in this electron microscope cytochemical study to determine the respiratory potency, integrity and fate of the Arbacia sperm mitochondrion at fertilization and during early embryogenesis. The sperm mitochondrion remained intact and was intensely positive for cytochrome oxidase activity both during and after penetration into the egg. The mitochondrion remained highly reactive throughout zygote formation, up to the eight-cell stage. The sperm mitochondrion formed many projections and buds in the cytoplasm of immature oocytes, monospermic and polyspermic eggs, and in blastomeres. At all stages of early embryogenesis, close juxtaposition and structural contact were observed between the highly reactive sperm mitochondrion and the less reactive egg mitochondria. The results suggest that following fertilization the mitochondrion of the sea urchin spermatozoon retains some degree of metabolic autonomy within the ooplasm. The structural integrity of the paternal mitochondrion is maintained along with a functional respiratory enzyme system (cytochrome c-a3). The hypothesis that the fertilizing sperm mitochondrion may have some relevance to sea urchin development is discussed.

The intracellular localization ofd-amino acid oxidase in rat kidney and liver has been investigated using the indirect immunogold postembedding technique. Different fixation and embedding conditions for optimal preservation of antigenicity and fine structure have been tested. Immunolabelling was possible only in tissues embedded in polar resins (glycol methacrylate and Lowicryl K4M). In kidney the enzyme was demonstrable only in the peroxisomes of the proximal tubule, where it was associated with the peroxisome core. The enzyme was present in all the peroxisomes of the proximal tubule and appeared to be codistributed with catalase. Control experiments and quantitative analysis confirmed the specificity of thed-amino acid oxidase immunolocalization. All the other cells in kidney failed to demonstrate any labelling. In liver, the immunolabelling was present in the matrix of the hepatocyte peroxisomes, whereas no traces of the enzyme were found in the nucleoid. The intensity of the immunolabelling in liver peroxisomes was lower than in kidney. No specific labelling was observed in cells other than hepatocytes.

Transmission electron micrographs, with and without prior infusion of horseradish peroxidase, and scanning electron microscopy of fractured corpora lutea demonstrated extensive microvillus development on the surface of rat luteal cells 7 days after priming with PMSG and hCG. These microvilli were primarily on the capillary face of the luteal cells, while the basolateral faces of the cell were largely composed of smooth plasma membrane with some gap junctions between adjoining cells, Injection of a small dose of [125I]-hCG revealed localization of silver grains primarily on the microvillus surfaces and, to lesser extents, on the basolateral plasma membrane and in subplasma membrane cytosolic vesicles. Pinocytosis was clearly demonstrated. Injection of a dose of [125I]-hCG sufficient to desensitize the hCG stimulatable adenylate cyclase and to result in extensive loss of hCG receptors did not enhance the transfer of silver grains into cytoplasmic vesicles. This dose of 125I]-hCG decreased the area occupied by microvilli and increased the area of basolateral membrane.

Sperm surface β-N-acetylhexosaminidases are among the molecules mediating early gamete interactions in invertebrates and vertebrates, including man. The plasma membrane of Drosophila spermatozoa contains two β-N-acetylhexosaminidases, DmHEXA and DmHEXB, which are required for egg fertilization. Here, we demonstrate that three putative Drosophila melanogaster genes predicted to code for β‐N-acetylhexosaminidases, Hexo1, Hexo2, and fdl, are all expressed in the male germ line. fdl codes for a homolog of the α-subunit of the mammalian lysosomal β-N-acetylhexosaminidase Hex A. Hexo1 and Hexo2 encode two homologs of the β-subunit of all known β-N-acetylhexosaminidases, which we have named β1 and β2, respectively. Immunoblot analysis of sperm proteins indicated that the gene products associate in different heterodimeric combinations forming DmHEXA, with an αβ2 structure, and DmHEXB, with a β1β2 structure. Immunofluorescence demonstrated that all the gene products localized to the sperm plasma membrane. Although none of the genes was testis-specific, fdl was highly and preferentially expressed in the testis, whereas Hexo1 and Hexo2 showed broader tissue expression. Enzyme assays carried out on testis and on a variety of somatic tissues corroborated the results of gene expression analysis. These findings for the first time show the in vivo expression in insects of genes encoding β-N-acetylhexosaminidases, the only molecules so far identified as involved in sperm/egg recognition in this class, whereas in mammals, the organisms where these enzymes have been best studied, only two types of polypeptide chains forming dimeric functional β-N-acetylhexosaminidases are present in Drosophila three different gene products are available that might generate numerous dimeric isoforms.

Experiments were conducted to develop an agar-based medium for rearing immature horn flies, Hematobia irritans (L.). Larval survival was determined on sterilized manure inoculated with pure and mixed cultures of Acinetobacter sp., Bacillus pumilus Meyer & Gottheil, Comamonas acidovorans den Dooren de Jong, Pseudomonas mendocina Palleroni, Flavobacterium sp. and Empedobacter breve (Holmes & Owen). Rearing larvae on mixed cultures enhanced pupal weight but not survival. Horn fly larvae failed to survive when reared on standard bacteriological media inoculated with pure and mixed cultures of Acinetobacter sp., P. mendocina, and C. acidovorans. Larvae completed development on a minimal medium supplemented with alfalfa, egg proteins, and vitamins. Medium with low alfalfa content (30 g alfalfa/500 ml minimal medium) had enhanced survival when supplemented with egg yolk protein and vitamins. Medium with high alfalfa content (130 g alfalfa/500 ml minimal medium) had enhanced survival when supplemented with whole egg protein and vitamins. Survival was also favored when media were inoculated with pure cultures of Acinetobacter or Acinetobacter mixed with either Pseudomonas or Comamonas. Individual plates could support larvae developing from up to 40 eggs, and survival was least variable when plates were inoculated with greater numbers of eggs. This rearing system shows promise as a means for conducting standardized bioassays on a meridic diet.

Twenty species of bacteria were isolated from cattle manure and seven species were isolated from the gut of larval horn fly Hematobia irritans (L.). Bacteria in manure belonged to the Bacillaceae, Pseudomonadaceae, Micrococcaceae, Corynebacteriaceae, Enterobacteriaceae, Microbacteriaceae, and two unassigned genera. Gut bacteria belonged to the Enterobacteriaceae, Bacillaceae, Neisseriaceae, and Pseudomonadaceae. H. irritans larval survival and growth on the various bacterial species were evaluated by rearing larvae in sterilized cattle manure that was inoculated with single bacterial isolates. H. irritans larvae failed to develop in sterilized, uninoculated manure, indicating that bacteria are necessary for larval development. Survival averaged 74% in nonsterilized manure and ranged from 4 to 53% in manure with individual isolates. Survival was highest when larvae were reared on manure inoculated with Pseudomonadaceae, Corynebacteriaceae, Micrococcaceae, and Bacillaceae and was lowest when reared in manure inoculated with Enterobacteriaceae and Microbacteriaceae. Pupal weights were heaviest when reared on the Flavobacteria, followed by the Pseudomonadaceae and Corynebacteriaceae. Pupae averaged 4.9 ± 0.08 mg when reared on gram-negative isolates, compared with 3.6 ± 0.09 mg when reared on gram-positive isolates. Pupal weights were not significantly correlated with larval survival, indicating that bacteria that promote growth do not necessarily promote survival. A reproductive index was used as a measure of fitness and was highest for larvae reared in the nonsterile control, followed most closely by Pseudomonadaceae and Corynebacteriaceae. These groups appeared to best meet the nutritional requirements of larvae and may be used in further experiments to define an artificial rearing media for H. irritans.