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Sample records for basal mollusk wirenia

  1. Noodling for Mollusks

    ERIC Educational Resources Information Center

    Sukkestad, Kathryn; Curran, Mary Carla

    2012-01-01

    Mollusks, such as mussels and snails, are a great group to noodle because they are prevalent in banks and bottoms of river basins and in sandy beach habitats. Furthermore, their shells are easy to come by and safe to handle. There are six classes within the phylum Mollusca. In the activities described in this article, the authors focus on the…

  2. Invasion of the striped mollusks

    SciTech Connect

    Not Available

    1991-09-01

    Introduced to this country only five years ago, the prolific zebra mussel has infested the Great Lakes and has already begun to move into fresh waters beyond the region. Dense populations in utility water systems have caused serious problems, reducing plant efficiency and blocking lines used for cooling and fire fighting. Experts say the striped mollusk has the potential to become the industry's worst biological problem, possibly affecting 70% of US power plants. While it appears that the invader is here to stay, EPRI and others continue to develop and refine techniques to control mussel growth. This article describes how the mollusk got here, reviews the problems it can cause and what is being done to mitigate the problems and control the growth and spread of the mollusk.

  3. RECENT BIOGENIC PHOSPHORITE: CONCRETIONS IN MOLLUSK KIDNEYS

    EPA Science Inventory

    Phosphorite concretions have been detected in the kidneys of two widespread species of mollusks. Mercenaria mercenaria and Argopecten irradians, which have relatively high population densities. These concretions are the first documentation of the direct biogenic formation of phos...

  4. Rostroconchia: A new class of bivalved mollusks

    USGS Publications Warehouse

    Pojeta, J., Jr.; Runnegar, B.; Morris, N.J.; Newell, N.D.

    1972-01-01

    Four Paleozoic bivalved genera are assigned to the new molluscan class Rostroconchia: Eopteria, Euchasma, Conocardium, and Pseudoconocardium. These mollusks have an uncoiled univalved larval shell; an untorted bivalved adult shell; no hinge teeth, ligament, or adductor muscles; and a fused, almost inflexible, hinge. Rostroconchians developed separately from the pelecypods through the ribeirioids, but are regarded as more closely related to the Pelecypoda and Scaphopoda than to other known classes of molllusks.

  5. Carbon isotopes in mollusk shell carbonates

    NASA Astrophysics Data System (ADS)

    McConnaughey, Ted A.; Gillikin, David Paul

    2008-10-01

    Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod shell carbonates. Land snails construct their shells mainly from respired CO2, and shell δ13C reflects the local mix of C3 and C4 plants consumed. Shell δ13C is typically >10‰ heavier than diet, probably because respiratory gas exchange discards CO2, and retains the isotopically heavier HCO3 -. Respired CO2 contributes less to the shells of aquatic mollusks, because CO2/O2 ratios are usually higher in water than in air, leading to more replacement of respired CO2 by environmental CO2. Fluid exchange with the environment also brings additional dissolved inorganic carbon (DIC) into the calcification site. Shell δ13C is typically a few ‰ lower than ambient DIC, and often decreases with age. Shell δ13C retains clues about processes such as ecosystem metabolism and estuarine mixing. Ca2+ ATPase-based models of calcification physiology developed for corals and algae likely apply to mollusks, too, but lower pH and carbonic anhydrase at the calcification site probably suppress kinetic isotope effects. Carbon isotopes in biogenic carbonates are clearly complex, but cautious interpretation can provide a wealth of information, especially after vital effects are better understood.

  6. The microindentation behavior of several mollusk shells

    SciTech Connect

    Laraia, V.J.; Heuer, A.H. . Dept. of Materials Science and Engineering)

    1990-01-01

    An investigation of the relationship between structure and mechanical behavior is reported for mollusk shells employing foliated, nacreous, and crossed-lamellar structures by microindentation in the Knoop and Vickers geometries. Indentation damage zones develop crack systems that reflect the micro-architecture. For the crosed-lamellar structure, the system of cracks about the indentation normally developed in a brittle material is suppressed. Previous reports that shells are harder than the corresponding minerals, calcite and aragonite, are confirmed, but it is found that this effect can be strongly dependent on orientation. This anomalous hardness is not an artifact of the indentation test technique, since scratch tests confirm the relative hardness of shell over the mineral. It is suggested that microstructural organization is of central importance in producing this hardness, as opposed to intrinsic properties of the mineral or matrix phases. 17 refs., 6 figs., 1 tab.

  7. Hemocyanin respiratory pigment in bivalve mollusks

    SciTech Connect

    Morse, M.P.; Meyhoefer, E.; Otto, J.J.; Kuzirian, A.M.

    1986-03-14

    Hemocyanins, high molecular weight oxygen-binding proteins, were identified in two species of protobranch bivalve mollusks, Acila castrensis and Yoldia limatula. Although hemocyanins have been reported in chitons, gastropods, and cephalopods, they have not been observed in the Class Bivalvia. In A. castrensis the dissociation products of hemocyanin, characterized by gel electrophoresis, had a subunit molecular weight of approximately 250K. Negatively stained preparations of extracted hemocyanin formed protein aggregates in the shape of cylinders measuring 35 by 38 nanometers. X-ray microanalysis of hemocyanin aggregates in thin sections of Y. limatula demonstrated the presence of copper in the molecules. The discovery of hemocyanin in the protobranchs reinforces the primitive nature of the taxon and is further evidence that the major molluscan classes have a common ancestry. 14 references, 3 figures.

  8. Recent biogenic phosphorite: Concretions in mollusk kidneys

    USGS Publications Warehouse

    Doyle, L.J.; Blake, N.J.; Woo, C.C.; Yevich, P.

    1978-01-01

    Phosphorite concretions have been detected in the kidneys of two widespread species ofmollusks, Mercenaria mercenaria and Argopecten irradians, which have relatively high population densities. These concretions are thefirst documentation of the direct biogenic formation of phosphorite grains. The concretions are principally amorphous calcium phosphate, which upon being heated yields an x-ray diffraction pattern which is essentially that of chlorapatite. These concretions appear to be a normal formation of the excretory process of mollusks under reproductive, environmental, or pollutant-induced stress. Biogenic production of phosphorite concretions over long periods of time and diagenetic change from amorphous to crystalline structure, coupled with secondary enrichment, may account for the formation of some marine phosphorite desposits which are not easily explained by the chemical precipitation- replacement hypothesis. Copyright ?? 1978 AAAS.

  9. Cumberlandian Mollusk Conservation Program. Activity 2: potential fish hosts

    SciTech Connect

    Koch, L.M.; Hickman, G.D.; Swor, C.T.

    1986-02-01

    Fish species from sand/gravel substrates and from rubble substrates which are the most likely hosts for Cumberlandian mussel fauna, C. caelata and Q. intermedia, from the Clinch, Duck, Elk, and Powell Rivers are reported. Infection with mollusk glochidia was used with overlap and occurrences to develop a ranking of each species potential as a suitable host for Cumberlandian mollusks. 12 ref., 4 figs., 9 tabs.

  10. Closed recirculating system for shrimp-mollusk polyculture

    NASA Astrophysics Data System (ADS)

    Wu, Xiongfei; Zhao, Zhidong; Li, Deshang; Chang, Kangmei; Tong, Zhuanshang; Si, Liegang; Xu, Kaichong; Ge, Bailin

    2005-12-01

    This paper deals with a new system of aquaculture, i.e., a closed recirculating system for shrimp-mollusk polyculture. The culture system consisted of several shrimp ponds, a mollusk water-purifying pond and a reservoir. During the production cycle, water circulated between the shrimp and mollusk ponds, and the reservoir compensated for water loss from seepage and evaporation. Constricted tagelus, Sinonovacula constricta, was selected as the cultured mollusk, and Pacific white shrimp, Litopenaeus vannamei, as the cultured shrimp. The main managing measures during the production cycle were: setting and using the aerators; introducting the probiotic products timely into the shrimp ponds; adopting a “pen-closing” method for controlling shrimp viral epidemics; setting the flow diversion barriers in the mollusk pond to keep the circulating water flowing through the pond along a sine-like curve and serve as substrate for biofilm; no direct feeding was necessary for the cultured mollusk until the co-cultured shrimp was harvested; natural foods in the water from the shrimp ponds was used for their foods. Two sets of the system were used in the experiment in 2002 and satisfactory results were achieved. The average yield of the shrimp was 11 943.5 kg/hm2, and that of the mollusk was 16 965 kg/hm2. After converting the mollusk yield into shrimp yield at their market price ratio, the food coefficient of the entire system averaged at as low as 0.81. The water quality in the ponds was maintained at a desirable level and no viral epidemics were discovered during the production cycle.

  11. Diversity of the RFamide Peptide Family in Mollusks

    PubMed Central

    Zatylny-Gaudin, Celine; Favrel, Pascal

    2014-01-01

    Since the initial characterization of the cardioexcitatory peptide FMRFamide in the bivalve mollusk Macrocallista nimbosa, a great number of FMRFamide-like peptides (FLPs) have been identified in mollusks. FLPs were initially isolated and molecularly characterized in model mollusks using biochemical methods. The development of recombinant technologies and, more recently, of genomics has boosted knowledge on their diversity in various mollusk classes. Today, mollusk FLPs represent approximately 75 distinct RFamide peptides that appear to result from the expression of only five genes: the FMRFamide-related peptide gene, the LFRFamide gene, the luqin gene, the neuropeptide F gene, and the cholecystokinin/sulfakinin gene. FLPs display a complex spatiotemporal pattern of expression in the central and peripheral nervous system. Working as neurotransmitters, neuromodulators, or neurohormones, FLPs are involved in the control of a great variety of biological and physiological processes including cardiovascular regulation, osmoregulation, reproduction, digestion, and feeding behavior. From an evolutionary viewpoint, the major challenge will then logically concern the elucidation of the FLP repertoire of orphan mollusk classes and the way they are functionally related. In this respect, deciphering FLP signaling pathways by characterizing the specific receptors these peptides bind remains another exciting objective. PMID:25386166

  12. Cumberlandian Mollusk Conservation Program. Activity 1: mussel distribution surveys

    SciTech Connect

    Ahlstedt, S.A.

    1986-01-01

    The distribution of Cumberlandian mollusks in the Tennessee Valley is one of nine research activities developed as part of TVA's Cumberlandian Mollusk Conservation Program (CMCP). The name Cumberlandian refers to an endemic faunal assemblage that encompasses portions of 7 states bordering the southern Appalachian Mountains and the Cumberland Plateau Region. This geographic region is known as one of the major centers for mussel speciation and is considered the most prolific areas of the world for this particular group of organisms. Nine Tennessee Valley streams were selected for intensive qualitative and quantitative mussel surveys under Activity I of the CMCP. The surveys were designed to gather information on the present distribution of Cumberlandian mollusks. The streams chosen for surveys were based on the documented presence of diverse mussel fauna, endangered mussels, and/or sufficient information (diverse fish fauna, good water quality, etc.) to suggest potential for occurrence of diverse mussel fauna or endangered species.

  13. Mollusks of Candomblé: symbolic and ritualistic importance

    PubMed Central

    2012-01-01

    Human societies utilize mollusks for myriad material and spiritual ends. An example of their use in a religious context is found in Brazil's African-derived belief systems. Candomblé, an Afro-Brazilian religion introduced during the 18th-19th centuries by enslaved Yoruba, includes various magical and liturgical uses of mollusks. This work inventoried the species utilized by adherents and to analyzed their symbolic and magical context. Data were obtained from Candomblé temples in two cities in the northeast of Brazil-Caruaru, in the state of Pernambuco, and Campina Grande, in the state of Paraíba. Questionnaires administered to eleven adepts revealed that at least nineteen mollusk species are being used. Shells from Monetaria moneta, M. annulus and Erosaria caputserpentis were cited by all of the interviewees. Three uses stood out: divination (jogo de búzios); utilization as ritual objects; and employment as sacrificial offerings (Igbin or Boi-de-Oxalá). The jogo de búzios (shell toss), employed in West Africa, Brazil and Cuba, is of fundamental importance to the cult, representing the means by which the faithful enter in contact with the divinities (Orixás) and consult people's futures (Odu). The utilization of mollusks in Candomblé is strongly influenced by ancient Yoruba myths (Itãs) which, having survived enslavement and generations of captive labor, continue to guide the lives of Brazil's African Diaspora. PMID:22420523

  14. CHEMICAL CARCINOGENS IN BIVALVE MOLLUSKS FROM OREGON ESTUARIES

    EPA Science Inventory

    The research undertaken involved the use of indigenous populatons of bivalve mollusks as monitors for detecting and quantifying environmental benzo(s)pyrene (BAP) in Oregon estuaries. Short-term and long-term studies were conducted in order to establish baseline levels of BAP and...

  15. Mollusks of Candomblé: symbolic and ritualistic importance.

    PubMed

    Léo Neto, Nivaldo A; Voeks, Robert A; Dias, Thelma L P; Alves, Rômulo R N

    2012-01-01

    Human societies utilize mollusks for myriad material and spiritual ends. An example of their use in a religious context is found in Brazil's African-derived belief systems. Candomblé, an Afro-Brazilian religion introduced during the 18th-19th centuries by enslaved Yoruba, includes various magical and liturgical uses of mollusks. This work inventoried the species utilized by adherents and to analyzed their symbolic and magical context. Data were obtained from Candomblé temples in two cities in the northeast of Brazil-Caruaru, in the state of Pernambuco, and Campina Grande, in the state of Paraíba. Questionnaires administered to eleven adepts revealed that at least nineteen mollusk species are being used. Shells from Monetaria moneta, M. annulus and Erosaria caputserpentis were cited by all of the interviewees. Three uses stood out: divination (jogo de búzios); utilization as ritual objects; and employment as sacrificial offerings (Igbin or Boi-de-Oxalá). The jogo de búzios (shell toss), employed in West Africa, Brazil and Cuba, is of fundamental importance to the cult, representing the means by which the faithful enter in contact with the divinities (Orixás) and consult people's futures (Odu). The utilization of mollusks in Candomblé is strongly influenced by ancient Yoruba myths (Itãs) which, having survived enslavement and generations of captive labor, continue to guide the lives of Brazil's African Diaspora. PMID:22420523

  16. Detection, isolation, and persistence of viruses within bivalve mollusks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Norovirus (NV), hepatitis A virus (HAV), and other virus transmission by molluscan shellfish is a significant issue. Research at the ARS-Dover DE laboratory has led to the development of improved methods for detecting these viruses. To identify pathogenic viruses within mollusks, a rapid highly-se...

  17. Anthropogenic effects on marine mollusks diversity and abundance; mangrove mollusks along an environmental gradient at Teyab, Persian gulf

    NASA Astrophysics Data System (ADS)

    Azarmanesh, H.; Javanshir, A.

    2009-04-01

    Management of coastal environments requires understanding of ecological relationships among different habitats and their biotas.. The mollusk diversity and density and sedimentological properties of mangrove (Avicennia marina) stands of two different seasons in Teyab have been compared. Pollutant area and cleaner area showed clear separation on the basis of environmental characteristics and benthic mollusks. Numbers of mollusks taxa were generally larger at cleaner sites, and numbers of individuals of several taxa were also larger at other sites. The total number of individuals was not different between the two seasons, largely due to the presence of large numbers of the Mud-living gastropod Cerithium cingulata at the pollutant sites. Differences in the Mollusks were coincident with differences in the nature of the sediment. Sediments in cleaner stands were more compacted and contained lesser organic matter and leaf litter.Analysis of sediment chemistry suggested that mangrove sediment in the Cleaner sites were able to take up more N and P than those in the other sites. Key Words: Sustainable development, Impact, Gastropods, Bivalves, Persian Gulf

  18. Basal Cell Carcinoma (BCC)

    MedlinePlus

    ... carcinomas: Infiltrating basal cell carcinomas can be more aggressive and locally destructive than other types of basal ... to treat them early and with slightly more aggressive techniques. Excision – The basal cell carcinoma is cut ...

  19. Mollusk shell nacre ultrastructure correlates with environmental temperature and pressure.

    PubMed

    Olson, Ian C; Kozdon, Reinhard; Valley, John W; Gilbert, Pupa U P A

    2012-05-01

    Nacre, or mother-of-pearl, the tough, iridescent biomineral lining the inner side of some mollusk shells, has alternating biogenic aragonite (calcium carbonate, CaCO(3)) tablet layers and organic sheets. Nacre has been common in the shells of mollusks since the Ordovician (450 million years ago) and is abundant and well-preserved in the fossil record, e.g., in ammonites. Therefore, if any measurable physical aspect of the nacre structure was correlated with environmental temperatures, one could obtain a structural paleothermometer of ancient climates. Using X-ray absorption near-edge structure (XANES) spectroscopy, Photoelectron emission spectromicroscopy (PEEM), and X-ray linear dichroism we acquired polarization-dependent imaging contrast (PIC) maps of pristine nacre in cross-section. The new PIC-map data reveal that the nacre ultrastructure (nacre tablet width, thickness, and angle spread) is species-specific in at least eight mollusk species from completely different environments: Nautilus pompilius, Haliotis iris, Haliotis rufescens, Bathymodiolus azoricus, Atrina rigida, Lasmigona complanata, Pinctada margaritifera, and Mytilus californianus. Nacre species-specificity is interpreted as a result of adaptation to diverging environments. We found strong correlation between nacre crystal misorientations and environmental temperature, further supported by secondary ion mass spectrometry measurements of in situ δ(18)O in the nacre of one shell. This has far-reaching implications: nacre texture may be used as a paleothermometer of ancient climate, spanning 450 million years of Earth's history. PMID:22313180

  20. Effects of contaminants on naiad mollusks (Unionidae): a review

    USGS Publications Warehouse

    Havlik, M.E.; Marking, L.L.

    1987-01-01

    Although the uptake, storage, and elimination of contaminants by naiad mollusks has been studied, relatively little information is available on toxicity. Contaminants appear to have destroyed some populations directly by exerting toxic effects, or indirectly by causing or contributing to the elimination of essential food organisms or host fish. The most frequently studied contaminants are Cd, Cu, Mn-Mn64, Pb-Pb210. and Zn-Zn65. Manganese seems to be most readily taken up and stored in tissues; no apparent damage has been reported from tissue concentrations of thousands of parts per million (ppm) and the element appears to be essential to metabolism. Zinc and cadmium also accumulate at high levels in tissues. Lead was never found to be lethal in the studies reviewed. Various common contaminants have been reported to be toxic at the following concentrations (ppm): cadmium. 2; copper sulfate, 2 to 18.7; ammonia, 5; potassium. 11; chromium, 12.4; arsenic trioxide, 16; copper, 19; and zinc, 66. In long-term exposures, concentrations of copper as low as 25 parts per billion (ppb) were lethal. Fry of fish infected with 20-35 glochidia were more sensitive than uninfected fish to toluene, naphthalene, and crude oil. Although few specific adverse impacts of contaminants have become clearly evident, circumstantial evidence leaves little doubt that contaminants have been responsible for decreases in population density, range, and diversity. Stresses that have been responsible for the disappearance of naiad mollusks in contaminated areas have not generally been identified, and the components of the stresses have seldom been quantitatively and qualitatively correlated with the composition and size of the naiad fauna. Often two or more factors appear to work in combination to produce the total stress that adversely affects populations. Naiad mollusks are important indio caters of contaminants in the environment; residues in soft tissue indicate recent or current exposure, and

  1. Mid-Neolithic Exploitation of Mollusks in the Guanzhong Basin of Northwestern China: Preliminary Results

    PubMed Central

    Li, Fengjiang; Wu, Naiqin; Lu, Houyuan; Zhang, Jianping; Wang, Weilin; Ma, Mingzhi; Zhang, Xiaohu; Yang, Xiaoyan

    2013-01-01

    Mollusk remains are abundant in archaeological sites in the Guanzhong Basin of Northwestern China, providing good opportunities for investigations into the use of mollusks by prehistoric humans. Here we report on freshwater gastropod and bivalve mollusks covering the time interval from about 5600 to 4500 cal. yrs BP from sites of Mid-Late Neolithic age. They are identified as Cipangopaludina chinensis and Unio douglasiae, both of which are currently food for humans. The shells are well preserved and have no signs of abrasion. They are all freshwater gastropods and bivalves found in pits without water-reworked deposits and have modern representatives which can be observed in rivers, reservoirs, and paddy fields in the studied region. Mollusk shells were frequently recovered in association with mammal bones, lithic artifacts, and pottery. These lines of evidence indicate that the mollusks are the remains of prehistoric meals. The mollusk shells were likely discarded into the pits by prehistoric humans after the flesh was eaten. However, these mollusk remains may not have been staple food since they are not found in large quantities. Mollusk shell tools and ornaments are also observed. Shell tools include shell knives, shell reaphooks and arrowheads, whereas shell ornaments are composed of pendants and loops. All the shell tools and ornaments are made of bivalve mollusks and do not occur in large numbers. The finding of these freshwater mollusk remains supports the view that the middle Holocene climate in the Guanzhong Basin may have been warm and moist, which was probably favorable to freshwater mollusks growing and developing in the region. PMID:23544050

  2. Mid-Neolithic exploitation of mollusks in the Guanzhong Basin of Northwestern China: preliminary results.

    PubMed

    Li, Fengjiang; Wu, Naiqin; Lu, Houyuan; Zhang, Jianping; Wang, Weilin; Ma, Mingzhi; Zhang, Xiaohu; Yang, Xiaoyan

    2013-01-01

    Mollusk remains are abundant in archaeological sites in the Guanzhong Basin of Northwestern China, providing good opportunities for investigations into the use of mollusks by prehistoric humans. Here we report on freshwater gastropod and bivalve mollusks covering the time interval from about 5600 to 4500 cal. yrs BP from sites of Mid-Late Neolithic age. They are identified as Cipangopaludina chinensis and Unio douglasiae, both of which are currently food for humans. The shells are well preserved and have no signs of abrasion. They are all freshwater gastropods and bivalves found in pits without water-reworked deposits and have modern representatives which can be observed in rivers, reservoirs, and paddy fields in the studied region. Mollusk shells were frequently recovered in association with mammal bones, lithic artifacts, and pottery. These lines of evidence indicate that the mollusks are the remains of prehistoric meals. The mollusk shells were likely discarded into the pits by prehistoric humans after the flesh was eaten. However, these mollusk remains may not have been staple food since they are not found in large quantities. Mollusk shell tools and ornaments are also observed. Shell tools include shell knives, shell reaphooks and arrowheads, whereas shell ornaments are composed of pendants and loops. All the shell tools and ornaments are made of bivalve mollusks and do not occur in large numbers. The finding of these freshwater mollusk remains supports the view that the middle Holocene climate in the Guanzhong Basin may have been warm and moist, which was probably favorable to freshwater mollusks growing and developing in the region. PMID:23544050

  3. Diagenetic changes in the elemental composition of unrecrystallized mollusk shells

    USGS Publications Warehouse

    Ragland, P.C.; Pilkey, O.H.; Blackwelder, B. W.

    1979-01-01

    The Mg, Sr, Mn, Fe, Na and K contents were determined for 230 apparently unrecrystallized mollusk shells (gastropods and bivalves) ranging in age from late Cretaceous to Holocene. Consistent differences between the Holocene and fossil shells with respect to concentrations of all these elements are attributed to postburial diagenetic changes. Fossil-Holocene shell comparisons are made on the intergeneric level, a more severe test of compositional differences than was previous work involved with few species. The observed differences re-emphasize the need for extreme caution in the use of the many geochemical tools which assume that no compositional changes have taken place prior to recrystallization of calcareous materials. ?? 1979.

  4. The organic-mineral interaction in mollusk shell

    NASA Astrophysics Data System (ADS)

    Metzler, Rebecca A.

    Macromolecules are a minority but important component of the minerals formed by living organisms, or biominerals. While many proteins from the nacre and prismatic layers of mollusk shells have been identified and sequenced, the molecular interaction, organization, and rearrangements of proteins upon organic-mineral bond formation, and the effect of this interaction on crystal formation, deformation, and orientation are poorly understood. To examine the organic-mineral interaction in mollusk shells, we prepared model systems consisting of calcium carbonate grown in the presence of synthetic mollusk shell polypeptides. X-ray absorption near-edge structure (XANES) spectroscopy and x-ray photoelectron emission microscopy (X-PEEM) were used to examine the electronic structure and bonding environment of both the surface and bulk of model biomineral crystals, thereby determining that the organic-mineral interaction is a series of events starting with bond formation and ending with the fully formed mineral. XANES spectra acquired from the model biomineral systems showed that upon organic-mineral bond formation both the crystal and the polypeptides exhibit bond and molecular structure alterations. We acquired XANES spectra from the surface of calcium carbonate crystals grown in the presence of six synthetic polypeptides sequenced after mollusk nacre proteins: AP7N, AP24N, N16N, asp1, asp2, and ACCN. All of these model biominerals gave similar results, namely the disruption of CO bonds in calcite and enhancement of the peaks associated with C-H bonds bonds in peptides, indicating disordering of the calcite crystal and ordering of the peptides upon binding. We also show that these changes do not occur when the acidic amino acids, Asp and Glu, are replaced in the N16N sequence with Asn and Gln, respectively, demonstrating the importance of carboxyl groups in organic-mineral bond formation. We examined the bulk crystal structure of crystals grown in the presence of N16N and asp

  5. Characterization of acidic polysaccharides from the mollusks through acid hydrolysis.

    PubMed

    Cao, Jiuling; Wen, Chengrong; Lu, Jiaojiao; Teng, Nan; Song, Shuang; Zhu, Beiwei

    2015-10-01

    Uronic acid-containing polysaccharides (UACPs) including glycosaminoglycans (GAGs) exist widely in nature. Herein we propose an elegant methodology to identify UACPs by analyzing their disaccharides produced from the acid hydrolysis using HPLC-MS(n) upon 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization. Based on the optimization of experimental conditions by the single factor experiment and orthogonal test design, the combination of 1.3M TFA at 105°C for 3h is found to be the optimum. Subsequently, these conditions were applied to investigate the distribution of UACPs in 20 selected species of edible Bivalvia and Gastropoda. PMP-disaccharides derived from UACPs in mollusks were identified by comparing the retention time and mass spectra with those of the reference PMP-disaccharides from hyaluronic acid (HA), chondroitin sulfate (CS), heparin (HP), and AGSP with →4)-GlcA(1→2)-Man(1→ repeating units. The analysis reveals the prevalence of CS in the shellfishes as well as the HP, and existence of three non-GAG UACPs in 7 mollusks. PMID:26076626

  6. Salinity and Temperature Tolerance Experiments on Selected Florida Bay Mollusks

    USGS Publications Warehouse

    Murray, James B.; Wingard, G. Lynn

    2006-01-01

    The ultimate goal of the Comprehensive Everglades Restoration Plan (CERP) is to restore and preserve the unique ecosystems of South Florida, including the estuaries. Understanding the effect of salinity and temperature changes, beyond typical oscillations, on the biota of South Florida's estuaries is a necessary component of achieving the goal of restoring the estuaries. The U.S. Geological Survey has been actively involved in researching the history of the South Florida Ecosystem, to provide targets, performance measures, and baseline data for restoration managers. These experiments addressed two aspects of ecosystem history research: 1) determining the utility of using molluscan shells as recorders of change in water chemistry parameters, primarily salinity, and 2) enhancing our in situ observations on modern assemblages by exceeding typically observed aquatic conditions. This set of experiments expanded our understanding of the effects of salinity, temperature and other water chemistry parameters on the reproduction, growth and overall survivability of key species of mollusks used in interpreting sediment core data. Observations on mollusks, plants and microbes made as part of these experiments have further refined our knowledge and understanding of the effects of ecosystem feedback and the role salinity and temperature play in ecosystem stability. The results have demonstrated the viability of several molluscan species as indicators of atypical salinity, and possibly temperature, modulations. For example Cerithium muscarum and Bulla striata demonstrated an ability to withstand a broad salinity and temperature range, with reproduction occurring in atypically high salinities and temperatures. These experiments also provided calibration data for the shell biogeochemistry of Chione cancellata and the possible use of this species as a water chemistry recorder. Observations made in the mesocosms, on a scale not normally observable in the field, have led to new

  7. What can a sessile mollusk tell about neotectonics?

    NASA Astrophysics Data System (ADS)

    Sivan, D.; Schattner, U.; Morhange, C.; Boaretto, E.

    2010-08-01

    Dendropoma petraeum are fixed vermitids (mollusk) that colonize and construct abrasion platform rims along rocky shorelines. These endemic mollusks are considered good relative sea level indicators in the eastern and the southern Mediterranean, due to their narrow habitat below the sea surface (about ±10 cm). The observed relative sea level values recorded (submerged, uplifted or at present mean sea level) reflect a superposition of eustatic, isostatic, tectonic and possibly local sedimentary instabilities. The present study examines fossil Dendropoma samples gathered along the Levant coast, from northern Israel to eastern Turkey. Conventional radiocarbon dates (from Turkey, Syria and partly in Lebanon) and 14C Accelerator Mass Spectrometer (AMS) from Lebanon and Israel yields Dendropoma ages ranging through Late Holocene. A numerical model is used for calculating the change in sea level through the Holocene as a function of glacio-hydrology and isostasy of the eastern Mediterranean. Space-time dependent subtractions of the model values are used to eliminate the eustatic component of the relative sea level, in order to obtain the tectonic component. Results show a general northward increase in tectonic uplift of the Levantine coast with different rates in different tectonic segments. This differential uplift corresponds well to the major tectonic segments comprising the Levantine continental margin since the Pleistocene, from the Carmel fault to the East Anatolian fault. Hence, these segments were still active during the last thousands years and even during the last hundreds years. The general trend of northward increase in vertical displacement is predominantly dictated by the convergence between the Sinai and Arabian plates with Anatolia and Eurasia, across the Cyprus arc and Zagros belt; and the secondarily dictated by the northward increase in convergence component across the sinistral Dead Sea Fault plate boundary.

  8. Autoimmune basal ganglia disorders.

    PubMed

    Dale, Russell C; Brilot, Fabienne

    2012-11-01

    The basal ganglia are deep nuclei in the brain that include the caudate, putamen, globus pallidus, and substantia nigra. Pathological processes involving the basal ganglia often result in disorders of movement and behavior. A number of different autoimmune disorders predominantly involve the basal ganglia and can result in movement and psychiatric disorders. The classic basal ganglia autoimmune disorder is Sydenham chorea, a poststreptococcal neuropsychiatric disorder. Resurgence in the interest in Sydenham chorea is the result of the descriptions of other poststreptococcal neuropsychiatric disorders including tics and obsessive-compulsive disorder, broadly termed pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection. Encephalitic processes affecting the basal ganglia are also described including the syndromes basal ganglia encephalitis, encephalitis lethargica, and bilateral striatal necrosis. Last, systemic autoimmune disorders such as systemic lupus erythematosus and antiphospholipid syndrome can result in chorea or parkinsonism. Using paradigms learned from other autoantibody associated disorders, the authors discuss the autoantibody hypothesis and the role of systemic inflammation in autoimmune basal ganglia disorders. Identification of these entities is important as the clinician has an increasing therapeutic repertoire to modulate or suppress the aberrant immune system. PMID:22832771

  9. Design-based and model-based inference in surveys of freshwater mollusks

    USGS Publications Warehouse

    Dorazio, R.M.

    1999-01-01

    Well-known concepts in statistical inference and sampling theory are used to develop recommendations for planning and analyzing the results of quantitative surveys of freshwater mollusks. Two methods of inference commonly used in survey sampling (design-based and model-based) are described and illustrated using examples relevant in surveys of freshwater mollusks. The particular objectives of a survey and the type of information observed in each unit of sampling can be used to help select the sampling design and the method of inference. For example, the mean density of a sparsely distributed population of mollusks can be estimated with higher precision by using model-based inference or by using design-based inference with adaptive cluster sampling than by using design-based inference with conventional sampling. More experience with quantitative surveys of natural assemblages of freshwater mollusks is needed to determine the actual benefits of different sampling designs and inferential procedures.

  10. Organochlorine Pesticides in Consumer Fish and Mollusks of Liaoning Province, China: Distribution and Human Exposure Implications

    PubMed Central

    Zhang, Hongmei; Tao, Minhui; Yang, Shaobin; Wang, Liwei; Liu, Ying; Ma, Dandan; He, Zhiming

    2010-01-01

    Fish and mollusk samples were collected from markets located in 12 cities in Liaoning province, China, during August and September 2007, and 22 organochlorine pesticides (OCPs) were detected. DDT, HCH, endosulfan, chlordane, and HCB were the dominating OCPs, with mean concentrations and ranges of, respectively, 15.41 and 0.57 to 177.56 ng/g, 0.84 and below detection limit (BDL) to 22.99 ng/g, 1.31 and BDL to 13.1 ng/g, 1.05 and BDL to 15.68 ng/g, and 0.63 and BDL to 9.21 ng/g in all fish and mollusk samples. The concentrations of other OCPs generally were low and were detectable in a minority of samples, reflecting the low levels of these OCPs in the study region. In general, OCP concentrations were obviously higher in fish than in mollusks, and higher in freshwater fish than in marine fish, which indicated, first, that freshwater fish are more easily influenced than seawater fish and mollusks by OCP residues in agricultural areas and, second, that there are different biota accumulation factors for OCPs between fish and mollusk. To learn the consumption of fish and mollusk, 256 questionnaires were sent to families in 12 cities of Liaoning province. Using the contamination data, average estimated daily intakes of OCPs via fish and mollusk consumption were calculated, which were used for exposure assessment. The public health risks caused by exposure to OCPs in the course of fish and mollusk consumption were compared to noncancer benchmarks and cancer benchmarks. PMID:20352204

  11. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks

    USGS Publications Warehouse

    Turgeon, D. D.; Quinn, J.F.; Bogan, A.E.; Coan, E. V.; Hochberg, F.G.; Lyons, W.G.; Mikkelsen, P. M.; Neves, R.J.; Roper, C. F. E.; Rosenberg, G.; Roth, B.; Scheltema, A.; Thompson, F.G.; Vecchione, M.; Williams, J.D.

    1998-01-01

    This edition of Common and Scientific Names of Invertebrates from the United States and Canada: Mollusks represents the efforts of 15 molluscan taxonomic specialists in compiling a comprehensive checklist of the mollusks found in North America and Canada and their vernacular names. Built upon the success of the first edition, the authors have updated the nomenclature to reflect recent phylogenetic analyses and have included more than 300 new species.

  12. Risk Assessment of Organochlorines in Mollusk from the Mediterranean and Red Sea Coasts of Egypt.

    PubMed

    El Nemr, Ahmed; El-Said, Ghada F; Khaled, Azza

    2016-04-01

    Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) residues were studied in different mollusk species from the Egyptian Mediterranean and Red Sea coasts. The average levels of OCPs in mollusks comprised chlordanes, dieldrins, total endrin, endosulfan compounds, and methoxychlor (DECEM), dichlorodiphenyltrichloroethanes (DDTs), and, hexachlorocyclohexanes (HCHs). The averages of HCHs, DDTs, and polychlorinated biphenyls (PCBs) in mollusks from the Mediterranean Sea were 1.13±1.21, 1.30±1.27, and 1.40±0.93 ng/g, respectively; from the Red Sea, they were 0.62±0.90, 1.77±1.82, and 6.44±5.05 ng/g, respectively. The analysis of HCHs, DDTs, and PCBs in mollusks indicates a new usage of lindane, PCB congeners, and the input of technical HCH and aged DDT. The data showed that the Red Sea Coast was more affected by PCBs congeners than the Mediterranean Sea Coast, which may be attributed to the different activities along the two coastal areas. Mollusks in the Mediterranean Sea had higher dieldrins, total endrin, endosulfan compounds, and methoxychlor contents than those in the Red Sea. Interestingly, HCHs, DDTs, and PCBs levels were lower than those recommended for Swedish Food Regulation and U.S. Food and Drug Administration, which means that mollusks from these two coastal areas are safe as food. PMID:27131056

  13. Basal Cell Carcinoma

    PubMed Central

    Lanoue, Julien

    2016-01-01

    Basal cell carcinoma is the most commonly occurring cancer in the world and overall incidence is still on the rise. While typically a slow-growing tumor for which metastases is rare, basal cell carcinoma can be locally destructive and disfiguring. Given the vast prevalence of this disease, there is a significant overall burden on patient well-being and quality of life. The current mainstay of basal cell carcinoma treatment involves surgical modalities, such as electrodessication and curettage, excision, cryosurgery, and Mohs micrographic surgery. Such methods are typically reserved for localized basal cell carcinoma and offer high five-year cure rates, but come with the risk of functional impairment, disfigurement, and scarring. Here, the authors review the evidence and indications for nonsurgical treatment modalities in cases where surgery is impractical, contraindicated, or simply not desired by the patient. PMID:27386043

  14. Basal cell skin cancer

    MedlinePlus

    ... occur in younger people who have had extensive sun exposure. You are more likely to get basal cell ... severe sunburns early in life Long-term daily sun exposure (such as the sun exposure received by people ...

  15. Basal cell cancer (image)

    MedlinePlus

    ... is needed to prove the diagnosis of basal cell carcinoma. Treatment varies depending on the size, depth, and location of the cancer. Early treatment by a dermatologist may result in a cure rate of more than 95%, but regular examination ...

  16. Bivalve mollusks in metal pollution studies: from bioaccumulation to biomonitoring.

    PubMed

    Zuykov, Michael; Pelletier, Emilien; Harper, David A T

    2013-09-01

    Contemporary environmental challenges have emphasized the need to critically assess the use of bivalve mollusks in chemical monitoring (identification and quantification of pollutants) and biomonitoring (estimation of environmental quality). Many authors, however, have considered these approaches within a single context, i.e., as a means of chemical (e.g. metal) monitoring. Bivalves are able to accumulate substantial amounts of metals from ambient water, but evidence for the drastic effects of accumulated metals (e.g. as a TBT-induced shell deformation and imposex) on the health of bivalves has not been documented. Metal bioaccumulation is a key tool in biomonitoring; bioavailability, bioaccumulation, and toxicity of various metals in relation to bivalves are described in some detail including the development of biodynamic metal bioaccumulation model. Measuring metal in the whole-body or the tissue of bivalves themselves does not accurately represent true contamination levels in the environment; these data are critical for our understanding of contaminant trends at sampling sites. Only rarely has metal bioaccumulation been considered in combination with data on metal concentrations in parts of the ecosystem, observation of biomarkers and environmental parameters. Sclerochemistry is in its infancy and cannot be reliably used to provide insights into the pollution history recorded in shells. Alteration processes and mineral crystallization on the inner shell surface are presented here as a perspective tool for environmental studies. PMID:23751124

  17. Neuron changes in a mollusk in response to proteolytic enzymes.

    PubMed

    Sotnikov, O S; Lukovnikova, M V; Vasyagina, N Yu; Laktionova, A A; Paramonova, N M

    2010-09-01

    The aims of the present work were to investigate the structure of neurons after treatment with proteases and to identify possible recovery of interneuronal syncytial connections. In the first series of experiments, phase-contrast microscopy studies of live dissociated neurons from ganglia of the mollusk Lymnaea stagnalis treated with 0.4% pronase solution demonstrated retraction of nerve processes and biphasic changes in cell body volume. At stage I, at an average of 82.5 min, neuron body volume decreased by 12.1%, after which it increased by a mean of 14.1%. Signs of neuron viability in Ringer's solution were seen for an average of 828 min; survival time in pronase solution was 1.4 times shorter. In the second series of experiments, studies of neuron ultrastructure showed many cases of persistence of mitochondria, the rough and smooth endoplasmic reticulum (ER), Golgi complex, light and granular vesicles, nuclear structure, and neuroplasm optical density. Cells coming close together after centrifugation formed intracellular clefts of uniform width (about 20 nm). There were very rare cases of points at which membranes came into contact. There were no signs of syncytial connections. Lengthening and fusion of smooth ER cisterns separated fragments of neuron bodies from relatively undamaged cells. Some neurons were damaged, with multiple vacuoles formed form swollen mitochondria and ER cisterns. Fragments of nerve processes formed on dissociation were surrounded by a normal outer cell membrane. PMID:20652422

  18. Oxygen and carbon isotopes in terrestrial mollusk shells. From modern to fossil values, climatic impact on the mollusk diet.

    NASA Astrophysics Data System (ADS)

    Metref, S.; Labonne, M.; Rousseau, D.; Rousseau, D.; Bentaleb, I.; Vianey-Liaud, M.

    2001-12-01

    Stable isotope studies on fossil material as well as on sediment have been very successful these past years indicating such method a very promising Quaternary paleonvironmental index for continental studies. Although most of the studies on fossil material was related to modern material collected near the fossil record, no precise analysis of the impact of the diet and precipitation was carried out in order to justify the previous assumptions. Here we present the results of two sets of analysis from terrestrial mollusk shells, a particularly good climate indicator. On one hand, individuals from hatched eggs of raised Helix aspersa were fed with different plants characteristic of the two main photosynthetic pathways (C3 and C4), and waters of different isotopic values. The shells were analyzed in order to observe the impact of the food diet and of the precipitation on the isotope content of the shell carbonate. On the other hand, the study of fossil shells (Vertigo modesta) from the loess series of the Great Plains, an area where shifts in photosynthetic pathways where detected during the last isotopic stage 2 (24,000-12,000 yr B.P.), is carried out. The interpretation of the results is based on those of the study of modern shells

  19. Genetic considerations for mollusk production in aquaculture: current state of knowledge

    PubMed Central

    Astorga, Marcela P.

    2014-01-01

    In 2012, world mollusk production in aquaculture reached a volume of 15,171,000 tons, representing 23% of total aquaculture production and positioning mollusks as the second most important category of aquaculture products (fishes are the first). Clams and oysters are the mollusk species with the highest production levels, followed in descending order by mussels, scallops, and abalones. In view of the increasing importance attached to genetic information on aquaculture, which can help with good maintenance and thus the sustainability of production, the present work offers a review of the state of knowledge on genetic and genomic information about mollusks produced in aquaculture. The analysis was applied to mollusks which are of importance for aquaculture, with emphasis on the 5 species with the highest production levels. According to FAO, these are: Japanese clam Ruditapes philippinarum; Pacific oyster Crassostrea gigas; Chilean mussel Mytilus chilensis; Blood clam Anadara granosa and Chinese clam Sinonovacula constricta. To date, the genomes of 5 species of mollusks have been sequenced, only one of which, Crassostrea gigas, coincides with the species with the greatest production in aquaculture. Another important species whose genome has been sequenced is Mytilus galloprovincialis, which is the second most important mussel in aquaculture production, after M. chilensis. Few genetic improvement programs have been reported in comparison with the number reported in fish species. The most commonly investigated species are oysters, with at least 5 genetic improvement programs reported, followed by abalones with 2 programs and mussels with one. The results of this work will establish the current situation with respect to the genetics of mollusks which are of importance for aquaculture production, in order to assist future decisions to ensure the sustainability of these resources. PMID:25540651

  20. Life beyond the Basal.

    ERIC Educational Resources Information Center

    Grey, Jeanne; Carbone, Carole

    1987-01-01

    Reading is a tool for learning. The goal for the teaching of reading must be to produce lovers of reading. A holistic approach should replace exclusive dependence on basal readers. Effective methods are the following: (1) language experience approach; (2) word banks; (3) pattern books; (4) sustained silent reading; and (5) directed…

  1. Structural organization of the nervous system of the mantle cavity wall and organs in prosobranch mollusks.

    PubMed

    Zaitseva, O V

    2003-03-01

    A variety of common histological stains was used, along with the Golgi and Colognier silver impregnation methods and electron microscopy, to perform a comparative study of the morphological characteristics of receptor and nerve cells and their interactions in the nervous system of the wall of the mantle cavity and mantle derivatives - gills, siphon, and osphradia - of the marine prosobranch gastropod mollusks Buccinum undatum and Littorina littorea. The results are discussed along with our own previously obtained data on the organization of the osphradial sensory organs and the afferent elements of the mantle cavity wall in other prosobranch mollusks - the terrestrial Pomatia elegans and the freshwater Viviparus contectus and Pomacea paludosa. Using the nervous system of the complex of mantle organs of prosobranch mollusks as examples, the structural features and evolutionary trends of the afferent part of the visceral nervous system of gastropods are discussed. PMID:12762596

  2. Role of bivalve mollusks in the sediment balance of the Anapa Bay Bar

    NASA Astrophysics Data System (ADS)

    Kosyan, A. R.; Kucheruk, N. V.; Flint, M. V.

    2012-02-01

    The sandy beaches of Anapa Bay Bar are a unique natural resource, but they are gradually being degrade under both natural and anthropogenic factors. The emissions of sand and shelly ground from the adjacent sea bottom partly compensate for this process. The concentration of carbonates may reach up to 50% in the beach sands, and most of these carbonates are of mollusk origin. The major deposit formation role belongs to the key bivalve species: Chamelea gallina (Linnaeus, 1758). The average biomass of this mollusk species reaches up to 450 g/m2 at the depths of 5-10 m. The other two subdominating mollusk species, the bivalve Donax trunculus (Linnaeus, 1758) and the gastropod Rapana venosa (Valenciennes, 1846), may impact as 16 g/m2 and 6 g/m2, respectively. Annually, 350 kg of shelly ground per running meter are newly deposited on Anapa beach.

  3. Mollusks from late Mesozoic seep deposits, chiefly in California.

    PubMed

    Kaim, Andrzej; Jenkins, Robert G; Tanabe, Kazushige; Kiel, Steffen

    2014-01-01

    Twenty-nine mollusk species from Late Jurassic to Eocene hydrocarbon seep deposits from California (USA), Japan, New Zealand, and Barbados are described and illustrated. Twenty species belong to Gastropoda and nine to Bivalvia. Seven new species, three new genera, and one new family are introduced. The gastropod Hikidea gen. nov. includes smooth-shelled Cantrainea-like colloniins from Cretaceous hydrocarbon seeps and plesiosaur falls. Hikidea osoensis sp. nov. is the oldest species of this genus. Chilodonta? reticulata sp. nov. is a distinctive vetigastropod though its supraspecific position is unclear. Phanerolepida onoensis sp. nov. is the first species of this colloniin genus from a seep deposit. We describe two new genera of Hokkaidoconchidae: Abyssomelania gen. nov. and Ascheria gen. nov.; this family includes now four genera (including Hokkaidoconcha and Humptulipsia) and ranges from the Late Jurassic to the Eocene. Abyssomelania is characterized by a large, high-spired shell and unusual widely-spaced prosocline riblets (here called abyssomelaniid riblets). Abyssomelania is represented by two new species: A. cramptoni sp. nov. from the Late Cretaceous of New Zealand and A. campbellae sp. nov. from the Early Cretaceous of California. Ascheria gen. nov. is characterized by a large high-spired cerithiform shell, a subsutural constriction, and mostly reticulate ornament. Two nominate species are included: Ascheria gigantea (Kiel et al., 2008) and A. eucosmeta (Ascher, 1906), both of Early Cretaceous age. Two further species potentially belonging to Ascheria from the Eocene of Barbados are reported in open nomenclature and are re-illustrated and re-described for comparison. Humtulipsia nobuharai sp. nov. is described based on specimens from the Campanian-Maastrichtian Sada Limestone seep deposit in Japan. The new family Paskentanidae fam. nov. is introduced for the genera Paskentana and Atresius. The species of this family are characterized by thin-shelled, broad

  4. Acute sensitivity of freshwater mollusks and commonly tested invertebrates to select chemicals with different toxic models of action

    EPA Science Inventory

    Previous studies indicate that freshwater mollusks are more sensitive than commonly tested organisms to some chemicals, such as copper and ammonia. Nevertheless, mollusks are generally under-represented in toxicity databases. Studies are needed to generate data with which to comp...

  5. The calibration of clumped-isotope thermometry on modern marine mollusk

    NASA Astrophysics Data System (ADS)

    Canavan, R. R.; Affek, H. P.; Zaarur, S.; Douglas, P. M.; Wang, Z.

    2013-12-01

    Clumped-isotope (Δ47) thermometry is a novel method to reconstruct paleotemperatures that can be applied to studying past coastal and marine environments using marine mollusk shells. Macrofossil mollusk shells are common in the fossil record and provide enough material to satisfy the relatively large-sample requirement for Δ47 analysis, making them ideal for clumped-isotope paleothermometry. If consistent with the clumped isotope thermometer, mollusk Δ47 derived temperatures should record local water temperatures during shell growth season. Recent studies, however, show strong deviations from the empirical Δ47-T calibration derived from synthetic calcite in some modern mollusk shells (cephalopods, gastropods and bivalves; Dennis et al., 2013; Henkes et al., 2013; Eagle et al., 2013) but not in others (bivalves; Douglas et al., submitted; Came et al., 2007). The source of these discrepancies has been hypothesized to be related to 1) different laboratory techniques (including sample preparation and instrument standardization), 2) growth of CaCO3 polymorphs (calcite, aragonite or vaterite) in shells, and 3) variable environmental growth conditions such as salinity and pH. We test the effect of CaCO3 polymorph, taxonomy, and mollusk growth conditions by comparing among Δ47 values of calcitic shells from eastern oysters (Crassostrea virginica), those of clam shells that are mostly aragonitic (collected along the United States' Atlantic coast), and published calibrations of the clumped isotope thermometer. Atlantic oysters were collected from 37°N to 43°N latitude, with temperatures ranging between ~ 10-25°C, and brackish to marine salinities ranging from 14.5 - 34 PSU. Clam genera were similarly collected along the coast between Florida up north to Maine with growth temperatures ranging from ~ 10-22 °C. We further examine whether the deviation from the calibration is related to the relatively low reproducibility observed in modern mollusk Δ47 measurements, and

  6. Nevoid basal cell carcinoma syndrome

    MedlinePlus

    ... of this disorder is a type of skin cancer called basal cell carcinoma , that develops around the time of puberty. Other ... if: You or any family members have nevoid basal cell carcinoma syndrome, especially if you are planning to have ...

  7. Progenesis in the evolution of the nudibranch mollusks genus Dendronotus (Gastropoda: Nudibranchia).

    PubMed

    Ekimova, I A; Malakhov, V V

    2016-03-01

    The morphology and postlarval ontogenesis of the radula in 11 species of the genus Dendronotus Alder et Hancock, 1845, has been studied. Four types of radula are recognized in adult mollusks. Proposed evidence suggests that small species of Dendronotus have evolved by progenesis. PMID:27193883

  8. 40 CFR 230.31 - Fish, crustaceans, mollusks, and other aquatic organisms in the food web.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... consumers to higher trophic levels. The reduction or potential elimination of food chain organism... aquatic organisms in the food web. 230.31 Section 230.31 Protection of Environment ENVIRONMENTAL... § 230.31 Fish, crustaceans, mollusks, and other aquatic organisms in the food web. (a) Aquatic...

  9. 40 CFR 230.31 - Fish, crustaceans, mollusks, and other aquatic organisms in the food web.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... consumers to higher trophic levels. The reduction or potential elimination of food chain organism... aquatic organisms in the food web. 230.31 Section 230.31 Protection of Environment ENVIRONMENTAL... § 230.31 Fish, crustaceans, mollusks, and other aquatic organisms in the food web. (a) Aquatic...

  10. 40 CFR 230.31 - Fish, crustaceans, mollusks, and other aquatic organisms in the food web.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... consumers to higher trophic levels. The reduction or potential elimination of food chain organism... aquatic organisms in the food web. 230.31 Section 230.31 Protection of Environment ENVIRONMENTAL... § 230.31 Fish, crustaceans, mollusks, and other aquatic organisms in the food web. (a) Aquatic...

  11. 40 CFR 230.31 - Fish, crustaceans, mollusks, and other aquatic organisms in the food web.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... consumers to higher trophic levels. The reduction or potential elimination of food chain organism... aquatic organisms in the food web. 230.31 Section 230.31 Protection of Environment ENVIRONMENTAL... § 230.31 Fish, crustaceans, mollusks, and other aquatic organisms in the food web. (a) Aquatic...

  12. 40 CFR 230.31 - Fish, crustaceans, mollusks, and other aquatic organisms in the food web.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Fish, crustaceans, mollusks, and other aquatic organisms in the food web. 230.31 Section 230.31 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING SECTION 404(b)(1) GUIDELINES FOR SPECIFICATION OF DISPOSAL SITES FOR DREDGED OR FILL MATERIAL...

  13. Effect of the 1982-1983 El Nino on bivalve mollusks. [Chione subrugosa; Trachycardium procerum

    SciTech Connect

    Rollins, H.B.

    1986-01-01

    Mollusks from the peruvian coast were studied in 1984 for shell patterns indicative of stress caused by the 1982-1983 El Nino. Analysis of growth increments showed physiological stress, and there was evidence (from interviews with fishermen) of sever mortality for some species.

  14. Venomous mollusks: the risks of human accidents by conus snails (gastropoda: conidae) in Brazil.

    PubMed

    Haddad, Vidal; de Paula Neto, João Batista; Cobo, Válter José

    2006-01-01

    Mollusks of the genus Conus present a venomous apparatus composed of radulae, a chitin structure linked to glands, which injects potent neurotoxic peptides, causing serious human envenomation and even death, associated with the blockage of certain receptors and muscular paralysis. No reported envenomation has occurred in Brazil, but certain populations are at risk of accidents. PMID:17160331

  15. Cortical basal ganglionic degeneration.

    PubMed

    Scarmeas, N; Chin, S S; Marder, K

    2001-10-01

    In this case study, we describe the symptoms, neuropsychological testing, and brain pathology of a retired mason's assistant with cortical basal ganglionic degeneration (CBGD). CBGD is an extremely rare neurodegenerative disease that is categorized under both Parkinsonian syndromes and frontal lobe dementias. It affects men and women nearly equally, and the age of onset is usually in the sixth decade of life. CBGD is characterized by Parkinson's-like motor symptoms and by deficits of movement and cognition, indicating focal brain pathology. Neuronal cell loss is ultimately responsible for the neurological symptoms. PMID:14602941

  16. Trace fossils of precambrian metazoans "Vendobionta" and "Mollusks"

    NASA Astrophysics Data System (ADS)

    Ivantsov, A. Yu.

    2013-05-01

    Metazoan trace fossils from the Upper Vendian are preserved together with remains of corresponding organisms. The traces belong to "Vendobionta", representing the Precambrian phylum Proarticulata and to a presumably trochophoran animal Kimberella quadrata. These organisms fed on microbial mats, which preserved fossil traces. Impressions of the mat surface structures, traces, and bodies of animals are preserved in marine terrigenous sediments on the basal surfaces of sandstone beds. Proarticulata grazing traces are represented by groups and chains of impressions left by the ventral side of a body or its central and posterior parts. Kimberella traces are represented by long ridges united into bundles, fans, and chains of fans. All these traces were largely formed mechanically, i.e., by mat scratching with cilia (Proarticulata) or teeth ( Kimberella). Proarticulata representatives destroyed only a thin upper layer of the mat, while Kimberella could possibly scratch the mat through its entire thickness or even tear off pieces from it.

  17. Paramecium tetraurelia basal body structure.

    PubMed

    Tassin, Anne-Marie; Lemullois, Michel; Aubusson-Fleury, Anne

    2015-01-01

    Paramecium is a free-living unicellular organism, easy to cultivate, featuring ca. 4000 motile cilia emanating from longitudinal rows of basal bodies anchored in the plasma membrane. The basal body circumferential polarity is marked by the asymmetrical organization of its associated appendages. The complex basal body plus its associated rootlets forms the kinetid. Kinetids are precisely oriented within a row in correlation with the cell polarity. Basal bodies also display a proximo-distal polarity with microtubule triplets at their proximal ends, surrounding a permanent cartwheel, and microtubule doublets at the transition zone located between the basal body and the cilium. Basal bodies remain anchored at the cell surface during the whole cell cycle. On the opposite to metazoan, there is no centriolar stage and new basal bodies develop anteriorly and at right angle from the base of the docked ones. Ciliogenesis follows a specific temporal pattern during the cell cycle and both unciliated and ciliated docked basal bodies can be observed in the same cell. The transition zone is particularly well organized with three distinct plates and a maturation of its structure is observed during the growth of the cilium. Transcriptomic and proteomic analyses have been performed in different organisms including Paramecium to understand the ciliogenesis process. The data have incremented a multi-organism database, dedicated to proteins involved in the biogenesis, composition and function of centrosomes, basal bodies or cilia. Thanks to its thousands of basal bodies and the well-known choreography of their duplication during the cell cycle, Paramecium has allowed pioneer studies focusing on the structural and functional processes underlying basal body duplication. Proteins involved in basal body anchoring are sequentially recruited to assemble the transition zone thus indicating that the anchoring process parallels the structural differentiation of the transition zone. This feature

  18. Human basal body basics.

    PubMed

    Vertii, Anastassiia; Hung, Hui-Fang; Hehnly, Heidi; Doxsey, Stephen

    2016-01-01

    In human cells, the basal body (BB) core comprises a ninefold microtubule-triplet cylindrical structure. Distal and subdistal appendages are located at the distal end of BB, where they play indispensable roles in cilium formation and function. Most cells that arrest in the G0 stage of the cell cycle initiate BB docking at the plasma membrane followed by BB-mediated growth of a solitary primary cilium, a structure required for sensing the extracellular environment and cell signaling. In addition to the primary cilium, motile cilia are present in specialized cells, such as sperm and airway epithelium. Mutations that affect BB function result in cilia dysfunction. This can generate syndromic disorders, collectively called ciliopathies, for which there are no effective treatments. In this review, we focus on the features and functions of BBs and centrosomes in Homo sapiens. PMID:26981235

  19. [Microsymbiocenosis of Codiella mollusks as a basis for symbiotic relations in the parasite-host system in opisthorchiasis].

    PubMed

    Kataeva, L V; Karpukhina, N F; Stepanova, K B; Kolotova, O N

    2014-01-01

    The purpose of the first step of microparasitocenosis investigation was to study the microbiocenosis of the first intermediate hosts of O. felineus--prosobranch gastropods of the genus Codiella, as well as their habitats. Materials were collected in the Iryum River of the Ob-Irtysh basin. The microflora of mollusks, water, and soil from their habitats was examined. The predominant flora was Aeromonas species in the biocenosis of mollusks and Enterobacteriaceae in the microbiocenosis of the water basin and soil. Examination of the microbial communities in the mollusks and their habitats showed that the range of microbial populations of mollusks was wider in species composition as compared to the microbiocenosis of soil and water. PMID:25286543

  20. Parasitizing of trematodes provokes warts on the hinge plate of the bivalve mollusk Macoma balthica Linnaeus, 1758 (Veneroida, Tellinidae).

    PubMed

    Gantsevich, M M; Strelkov, P P; Basova, L A; Malakhov, V V

    2016-01-01

    The hypothesis on non-random correlation between abnormalities in the structure of hinge plate and infection of mollusks Macoma balthica with trematodes of the family Gymnophallidae has been tested on the basis of material from the Barents Sea. Significant correlation between the presence of warts and infection was established upon intraand interpopulation comparison. The hypothesis states that parasitizing of trematodes in the extrapallial cavity of mollusks influences the mantle functioning and provokes abnormalities in the hinge plate structure. PMID:27021361

  1. Development of electric environment to control mollusk-shaped gel robots made of electroactive polymer PAMPS gel

    NASA Astrophysics Data System (ADS)

    Otake, Mihoko; Inaba, Masayuki; Inoue, Hirochika

    2000-06-01

    This paper describes the design and implementation of electric fields to actuate mollusk-shaped robots made entirely of PAMPS gel, which is a kind of electro-active polymer (EAP). The purpose of this study is to develop a system to control the shape of both simulated and real gel robots using electric fields. We present a modeling framework and experimental results using a prototype mollusk-shaped EAP robot that locomotes by changing the shape of its whole body.

  2. Cationic surfactants for control of fresh- and saltwater mollusks in nuclear cooling systems

    SciTech Connect

    Post, R.M.; Mallen, E.; Lehmann, F.

    1991-11-01

    One result of the release of the US Nuclear Regulatory Commission's Generic Letter 89-13, Service Water Problems Affecting Safety-Related Equipment, was the heightened awareness of the nuclear industry to the problems of macrofouling in heat exchange systems. The principal mollusk species that contribute to freshwater macrofouling problems are Asiatic Clam (southern United States) and Zebra Mussel (Great Lakes). The predominant saltwater fouling mollusks are the Blue Mussel (Pacific, northern Atlantic), Ribbed Mussel (southern Atlantic, Gulf Coast), and American Oyster (Atlantic, Gulf Coast). The nuclear community's awareness of macrofouling problems and the ineffectiveness of intermittent chlorination programs have led to the development of several chemical control technologies for eliminating macrofouling organism infestation. One technology that has proven effective for the control of macrofouling organisms is the periodic addition of a combination of two cationic charged surfactants, specifically, alkyldimethylbenzylammonium chloride (QUAT) and dodecyl guanidine hydrochloride (DGH). Experience with the cationic surfactants at several nuclear power plants is reported.

  3. Biosorption of divalent Pb, Cd and Zn on aragonite and calcite mollusk shells.

    PubMed

    Du, Yang; Lian, Fei; Zhu, Lingyan

    2011-07-01

    The potential of using mollusk shell powder in aragonite (razor clam shells, RCS) and calcite phase (oyster shells, OS) to remove Pb(2+), Cd(2+) and Zn(2+) from contaminated water was investigated. Both biogenic sorbents displayed very high sorption capacities for the three metals except for Cd on OS. XRD, SEM and XPS results demonstrated that surface precipitation leading to crystal growth took place during sorption. Calcite OS displayed a remarkably higher sorption capacity to Pb than aragonite RCS, while the opposite was observed for Cd. However, both sorbents displayed similar sorption capacities to Zn. These could be due to the different extent of matching in crystal lattice between the metal bearing precipitate and the substrates. The initial pH of the solution, sorbent's dosage and grain size affected the removal efficiency of the heavy meals significantly, while the organic matter in mollusk shells affected the removal efficiency to a lesser extent. PMID:21550150

  4. Environmental heterogeneity predicts species richness of freshwater mollusks in sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Hauffe, T.; Schultheiß, R.; Van Bocxlaer, B.; Prömmel, K.; Albrecht, C.

    2014-12-01

    Species diversity and how it is structured on a continental scale is influenced by stochastic, ecological, and evolutionary driving forces, but hypotheses on determining factors have been mainly examined for terrestrial and marine organisms. The extant diversity of African freshwater mollusks is in general well assessed to facilitate conservation strategies and because of the medical importance of several taxa as intermediate hosts for tropical parasites. This historical accumulation of knowledge has, however, not resulted in substantial macroecological studies on the spatial distribution of freshwater mollusks. Here, we use continental distribution data and a recently developed method of random and cohesive allocation of species distribution ranges to test the relative importance of various factors in shaping species richness of Bivalvia and Gastropoda. We show that the mid-domain effect, that is, a hump-shaped richness gradient in a geographically bounded system despite the absence of environmental gradients, plays a minor role in determining species richness of freshwater mollusks in sub-Saharan Africa. The western branch of the East African Rift System was included as dispersal barrier in richness models, but these simulation results did not fit observed diversity patterns significantly better than models where this effect was not included, which suggests that the rift has played a more complex role in generating diversity patterns. Present-day precipitation and temperature explain richness patterns better than Eemian climatic condition. Therefore, the availability of water and energy for primary productivity during the past does not influence current species richness patterns much, and observed diversity patterns appear to be in equilibrium with contemporary climate. The availability of surface waters was the best predictor of bivalve and gastropod richness. Our data indicate that habitat diversity causes the observed species-area relationship, and hence, that

  5. Comparative uptake from sea water and tissue distribution of 60Co in marine mollusks

    SciTech Connect

    Carvalho, F.P.

    1987-07-01

    Five different species of marine mollusks, Mytilus galloprovincialis Lmk., Tapes decussatus L., Cerastoderma (Cardium) edule (L.), Donax vittatus (da Costa) and Patella vulgata L., were exposed to /sup 60/Co-labelled sea water under laboratory conditions. After a 1-mo exposure, tested species reached different whole-body /sup 60/Co concentration factors (CF) over radioactive sea water of 73 +/- 27, 22 +/- 10, 84 +/- 25, 6.3 +/- 1.4 and 31 +/- 10, respectively, which are not dependent upon the size of mollusks. Equations for the experimental uptake curves, obtained using a multi-exponential model, indicate that /sup 60/Co uptake by mollusks involves two or three compartments, according to the species. In all species, the larger compartments turn over with long biological half-lives, dependent upon species. At the beginning of the experiment, /sup 60/CoCl2 added to sea water was mainly in cationic forms. These forms were progressively converted into anionic plus neutral forms most likely due to complex formation with organic ligands. With time this physico-chemical evolution had a lowering effect on /sup 60/Co bioaccumulation by mollusks. Analysis of /sup 60/Co in tissues revealed that Donax shell and mantle do not accumulate the radionuclide in great quantities, generating the low whole-body concentration factor found. In contrast, shell and mantle from all other species displayed variable but high CFs. Shell by itself accounts for more than half of the /sup 60/Co whole-body burden. Among soft tissues, gills and viscera displayed the highest CF and muscle the lowest. From these experiments, one may conclude that significant differences among species do exist regarding Co bioaccumulation potential.

  6. Bacillary Necrosis, a Disease of Larval and Juvenile Bivalve Mollusks I. Etiology and Epizootiology

    PubMed Central

    Tubiash, Haskell S.; Chanley, Paul E.; Leifson, Einar

    1965-01-01

    Tubiash, Haskell S. (U.S. Bureau of Commercial Fisheries, Milford, Conn.), Paul E. Chanley, and Einar Leifson. Bacillary necrosis, a disease of larval and juvenile bivalve mollusks. I. Etiology and epizootiology. J. Bacteriol. 90:1036–1044. 1965.—Lethal bacterial infections of a variety of hatchery-spawned bivalve mollusk larvae and juveniles have been studied. The symptoms of the disease and the course of the infection are described. Four biotypes and five antigenic types of bacteria, pathogenic for the larvae of five species of bivalve mollusks, were isolated and described in some detail. All are gram-negative motile rods. Comparative studies were made of a fairly large number of similar bacteria isolated from presumably normal marine fauna. None of these was pathogenic for the bivalve larvae nor did they have antigens in common with the pathogenic group. The four biotypes had a number of characteristics in common that rarely were present in other cultures from marine fauna. Several antibiotic preparations proved to be of value in the treatment and control of the infection. Images PMID:5847794

  7. Nature’s Palette: Characterization of Shared Pigments in Colorful Avian and Mollusk Shells

    PubMed Central

    Brennan, Patricia L. R.; Hanley, Daniel; Grim, Tomáš; Hauber, Mark E.; Holford, Mandë

    2015-01-01

    Pigment-based coloration is a common trait found in a variety of organisms across the tree of life. For example, calcareous avian eggs are natural structures that vary greatly in color, yet just a handful of tetrapyrrole pigment compounds are responsible for generating this myriad of colors. To fully understand the diversity and constraints shaping nature’s palette, it is imperative to characterize the similarities and differences in the types of compounds involved in color production across diverse lineages. Pigment composition was investigated in eggshells of eleven paleognath bird taxa, covering several extinct and extant lineages, and shells of four extant species of mollusks. Birds and mollusks are two distantly related, calcareous shell-building groups, thus characterization of pigments in their calcareous structures would provide insights to whether similar compounds are found in different phyla (Chordata and Mollusca). An ethylenediaminetetraacetic acid (EDTA) extraction protocol was used to analyze the presence and concentration of biliverdin and protoporphyrin, two known and ubiquitous tetrapyrrole avian eggshell pigments, in all avian and molluscan samples. Biliverdin was solely detected in birds, including the colorful eggshells of four tinamou species. In contrast, protoporphyrin was detected in both the eggshells of several avian species and in the shells of all mollusks. These findings support previous hypotheses about the ubiquitous deposition of tetrapyrroles in the eggshells of various bird lineages and provide evidence for its presence also across distantly related animal taxa. PMID:26650398

  8. Mercury accumulation in hydrothermal vent mollusks from the southern Tonga Arc, southwestern Pacific Ocean.

    PubMed

    Lee, Seyong; Kim, Se-Joo; Ju, Se-Jong; Pak, Sang-Joon; Son, Seung-Kyu; Yang, Jisook; Han, Seunghee

    2015-05-01

    We provide the mercury (Hg) and monomethylmercury (MMHg) levels of the plume water, sulfide ore, sediment, and mollusks located at the hydrothermal vent fields of the southern Tonga Arc, where active volcanism and intense seismic activity occur frequently. Our objectives were: (1) to address the potential release of Hg from hydrothermal fluids and (2) to examine the distribution of Hg and MMHg levels in hydrothermal mollusks (mussels and snails) harboring chemotrophic bacteria. While high concentrations of Hg in the sediment and Hg, As, and Sb in the sulfide ore indicates that their source is likely hydrothermal fluids, the MMHg concentration in the sediment was orders of magnitude lower than the Hg (<0.001%). It suggests that Hg methylation may have not been favorable in the vent field sediment. In addition, Hg concentrations in the mollusks were much higher (10-100 times) than in other hydrothermal vent environments, indicating that organisms located at the Tonga Arc are exposed to exceedingly high Hg levels. While Hg concentration was higher in the gills and digestive glands than in the mantles and residues of snails and mussels, the MMHg concentrations in the gills and digestive glands were orders of magnitude lower (0.004-0.04%) than Hg concentrations. In summary, our results suggest that the release of Hg from the hydrothermal vent fields of the Tonga Arc and subsequent bioaccumulation are substantial, but not for MMHg. PMID:25748345

  9. Nature's Palette: Characterization of Shared Pigments in Colorful Avian and Mollusk Shells.

    PubMed

    Verdes, Aida; Cho, Wooyoung; Hossain, Marouf; Brennan, Patricia L R; Hanley, Daniel; Grim, Tomáš; Hauber, Mark E; Holford, Mandë

    2015-01-01

    Pigment-based coloration is a common trait found in a variety of organisms across the tree of life. For example, calcareous avian eggs are natural structures that vary greatly in color, yet just a handful of tetrapyrrole pigment compounds are responsible for generating this myriad of colors. To fully understand the diversity and constraints shaping nature's palette, it is imperative to characterize the similarities and differences in the types of compounds involved in color production across diverse lineages. Pigment composition was investigated in eggshells of eleven paleognath bird taxa, covering several extinct and extant lineages, and shells of four extant species of mollusks. Birds and mollusks are two distantly related, calcareous shell-building groups, thus characterization of pigments in their calcareous structures would provide insights to whether similar compounds are found in different phyla (Chordata and Mollusca). An ethylenediaminetetraacetic acid (EDTA) extraction protocol was used to analyze the presence and concentration of biliverdin and protoporphyrin, two known and ubiquitous tetrapyrrole avian eggshell pigments, in all avian and molluscan samples. Biliverdin was solely detected in birds, including the colorful eggshells of four tinamou species. In contrast, protoporphyrin was detected in both the eggshells of several avian species and in the shells of all mollusks. These findings support previous hypotheses about the ubiquitous deposition of tetrapyrroles in the eggshells of various bird lineages and provide evidence for its presence also across distantly related animal taxa. PMID:26650398

  10. Lipids and Fatty Acids of Nudibranch Mollusks: Potential Sources of Bioactive Compounds

    PubMed Central

    Zhukova, Natalia V.

    2014-01-01

    The molecular diversity of chemical compounds found in marine animals offers a good chance for the discovery of novel bioactive compounds of unique structures and diverse biological activities. Nudibranch mollusks, which are not protected by a shell and produce chemicals for various ecological uses, including defense against predators, have attracted great interest for their lipid composition. Lipid analysis of eight nudibranch species revealed dominant phospholipids, sterols and monoalkyldiacylglycerols. Among polar lipids, 1-alkenyl-2-acyl glycerophospholipids (plasmalogens) and ceramide-aminoethyl phosphonates were found in the mollusks. The fatty acid compositions of the nudibranchs differed greatly from those of other marine gastropods and exhibited a wide diversity: very long chain fatty acids known as demospongic acids, a series of non-methylene-interrupted fatty acids, including unusual 21:2∆7,13, and an abundance of various odd and branched fatty acids typical of bacteria. Symbiotic bacteria revealed in some species of nudibranchs participate presumably in the production of some compounds serving as a chemical defense for the mollusks. The unique fatty acid composition of the nudibranchs is determined by food supply, inherent biosynthetic activities and intracellular symbiotic microorganisms. The potential of nudibranchs as a source of biologically active lipids and fatty acids is also discussed. PMID:25196731

  11. Soft-shell clam, Mya arenaria, a convenient laboratory animal for screening pathogens of bivalve mollusks.

    PubMed

    Tubiash, H S

    1971-09-01

    Attempts to introduce infectious or foreign material into oysters and other bivalve mollusks usually involve force or trauma because of immediate, prolonged adduction of the tightly closing valves. The soft-shell clam, Mya arenaria, is unable to seal its valves completely and relaxes readily, exposing soft tissue and a large siphon. This species is free from fouling organisms and is readily available at all seasons in the New England and mid-Atlantic areas. Suspensions of five strains of Vibrio sp. that cause bacillary necrosis in larval and juvenile bivalve mollusks were injected into the heart, siphon tissue, and the incurrent and excurrent siphon lumina of soft-shell clams. All vibrio strains caused significant mortality, usually within 2 days. Heaviest losses resulted from heart and excurrent siphon injections. No mortality occurred in control clams injected with seawater, broth, Serratia sp., and Escherichia coli. The soft-shell clam appears to be a useful animal for testing the pathogenicity of marine microorganisms for bivalve mollusks. PMID:4940871

  12. The curse of physiology—challenges and opportunities in the interpretation of geochemical data from mollusk shells

    NASA Astrophysics Data System (ADS)

    Schöne, Bernd R.

    2008-10-01

    Physiology corrupts geochemical records of mollusk shells in many ways, e.g., by actively controlling the incorporation of trace elements in the skeleton. However, the effects of variable biomineralization rates and growth cessation have largely remained unconsidered. Mediated by endogenous timekeeping mechanisms, mollusks stop growing skeletal material on a regular basis ranging from ultradian to annual timescales. During growth cessation, the shells do not record environmental conditions. Shell growth also stops when environmental conditions are beyond the physiological tolerance of the organism, e.g., above and below genetically determined, species-specific thermal extremes where shell growth slows and eventually ceases. Such growth disruptions can occur at non-periodic time intervals. Due to growth retardations and halts, proxy records of mollusk shells are thus incomplete, and reconstructed environmental amplitudes prone to truncation. Furthermore, environmental records are biased toward the physiological optimum of the animal. Favorable environmental conditions increase shell growth, whereas adverse environmental conditions result in reduced shell production and lowered overall metabolism. Not least, the duration of the growing season and overall growth rate decrease as the mollusk grows older. Mathematical modeling approaches can significantly improve proxy records obtained from mollusk shells. For example, if the duration of growth cessation is known, it may be possible to model the missing environmental record. It is also fairly easy to account for age-related growth trends, or variable time-averaging in different portions of the shell. However, a major premise for a reliable interpretation of proxy records from a mollusk shell or other organisms secreting biogenic hard parts is a proper understanding of the physiology, and of course, a high-resolution record of the many different environmental factors that may influence physiology and shell growth. The

  13. The Nervous Systems of Basally Branching Nemertea (Palaeonemertea)

    PubMed Central

    Beckers, Patrick; Loesel, Rudi; Bartolomaeus, Thomas

    2013-01-01

    In recent years, a lot of studies have been published dealing with the anatomy of the nervous system in different spiralian species. The only nemertean species investigated in this context probably shows derived characters and thus the conditions found there are not useful in inferring the relationship between nemerteans and other spiralian taxa. Ingroup relationships within Nemertea are still unclear, but there is some agreement that the palaeonemerteans form a basal, paraphyletic grade. Thus, palaeonemertean species are likely the most informative when comparing with other invertebrate groups. We therefore analyzed the nervous system of several palaeonemertean species by combining histology and immunostaining. 3D reconstructions based on the aligned slices were performed to get an overall impression of the central nervous system, and immunohistochemistry was chosen to reveal fine structures and to be able to compare the data with recently published results. The insights presented here permit a first attempt to reconstruct the primary organization of the nemertean nervous system. This comparative analysis allows substantiating homology hypotheses for nerves of the peripheral nervous system. This study also provides evidence that the nemertean brain primarily consists of two lobes connected by a strong ventral commissure and one to several dorsal commissures. During nemertean evolution, the brain underwent continuous compartmentalization into a pair of dorsal and ventral lobes interconnected by commissures and lateral tracts. Given that this conclusion can be corroborated by cladistic analyses, nemerteans should share a common ancestor with spiralians that primarily have a simple brain consisting of paired medullary, frontally commissurized and reinforced cords. Such an organization resembles the situation found in presumably basally branching annelids or mollusks. PMID:23785478

  14. The nervous systems of basally branching nemertea (palaeonemertea).

    PubMed

    Beckers, Patrick; Loesel, Rudi; Bartolomaeus, Thomas

    2013-01-01

    In recent years, a lot of studies have been published dealing with the anatomy of the nervous system in different spiralian species. The only nemertean species investigated in this context probably shows derived characters and thus the conditions found there are not useful in inferring the relationship between nemerteans and other spiralian taxa. Ingroup relationships within Nemertea are still unclear, but there is some agreement that the palaeonemerteans form a basal, paraphyletic grade. Thus, palaeonemertean species are likely the most informative when comparing with other invertebrate groups. We therefore analyzed the nervous system of several palaeonemertean species by combining histology and immunostaining. 3D reconstructions based on the aligned slices were performed to get an overall impression of the central nervous system, and immunohistochemistry was chosen to reveal fine structures and to be able to compare the data with recently published results. The insights presented here permit a first attempt to reconstruct the primary organization of the nemertean nervous system. This comparative analysis allows substantiating homology hypotheses for nerves of the peripheral nervous system. This study also provides evidence that the nemertean brain primarily consists of two lobes connected by a strong ventral commissure and one to several dorsal commissures. During nemertean evolution, the brain underwent continuous compartmentalization into a pair of dorsal and ventral lobes interconnected by commissures and lateral tracts. Given that this conclusion can be corroborated by cladistic analyses, nemerteans should share a common ancestor with spiralians that primarily have a simple brain consisting of paired medullary, frontally commissurized and reinforced cords. Such an organization resembles the situation found in presumably basally branching annelids or mollusks. PMID:23785478

  15. [Basal and spinous cell epitheliomas].

    PubMed

    Shaw, M; Sanguinetti, O; de Kaminsky, A R; Kaminsky, C A

    1975-01-01

    A study on 502 epithelial cutaneous cancers was carried out by the authors. The study included 377 basal cell carcinomas (57,5% in males and 42,4% in females) and 125 squamous cell carcinomas (78,4% in males and 21,6% in females). The basal cell carcinomas in both sexs had an earlier onset than the squamous cell carcinomas. PMID:1241706

  16. [Anti-basal ganglia antibody].

    PubMed

    Hayashi, Masaharu

    2013-04-01

    Sydenham's chorea (SC) is a major manifestation of rheumatic fever, and the production of anti-basal ganglia antibodies (ABGA) has been proposed in SC. The pathogenesis is hypothesized as autoimmune targeting of the basal ganglia via molecular mimicry, triggered by streptococcal infection. The spectrum of diseases in which ABGA may be involved has been broadened to include other extrapyramidal movement disorders, such as tics, dystonia, and Parkinsonism, as well as other psychiatric disorders. The autoimmune hypothesis in the presence and absence of ABGA has been suggested in Tourette's syndrome (TS), early onset obsessive-compulsive disorders (OCD), and pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS). Recently, the relationship between ABGA and dopamine neurons in the basal ganglia has been examined, and autoantibodies against dopamine receptors were detected in the sera from patients with basal ganglia encephalitis. In Japan, the occurrence of subacute encephalitis, where patients suffer from episodes of altered behavior and involuntary movements, has increased. Immune-modulating treatments are effective, indicating the involvement of an autoimmune mechanism. We aimed to detect the anti-neuronal autoantibodies in such encephalitis, using immunohistochemical assessment of patient sera. The sera from patients showing involuntary movements had immunoreactivity for basal ganglia neurons. Further epitopes for ABGA will be investigated in basal ganglia disorders other than SC, TS, OCD, and PANDAS. PMID:23568985

  17. Phylogenetic support values are not necessarily informative: the case of the Serialia hypothesis (a mollusk phylogeny)

    PubMed Central

    Wägele, J Wolfgang; Letsch, Harald; Klussmann-Kolb, Annette; Mayer, Christoph; Misof, Bernhard; Wägele, Heike

    2009-01-01

    Background Molecular phylogenies are being published increasingly and many biologists rely on the most recent topologies. However, different phylogenetic trees often contain conflicting results and contradict significant background data. Not knowing how reliable traditional knowledge is, a crucial question concerns the quality of newly produced molecular data. The information content of DNA alignments is rarely discussed, as quality statements are mostly restricted to the statistical support of clades. Here we present a case study of a recently published mollusk phylogeny that contains surprising groupings, based on five genes and 108 species, and we apply new or rarely used tools for the analysis of the information content of alignments and for the filtering of noise (masking of random-like alignment regions, split decomposition, phylogenetic networks, quartet mapping). Results The data are very fragmentary and contain contaminations. We show that that signal-like patterns in the data set are conflicting and partly not distinct and that the reported strong support for a "rather surprising result" (monoplacophorans and chitons form a monophylum Serialia) does not exist at the level of primary homologies. Split-decomposition, quartet mapping and neighbornet analyses reveal conflicting nucleotide patterns and lack of distinct phylogenetic signal for the deeper phylogeny of mollusks. Conclusion Even though currently a majority of molecular phylogenies are being justified with reference to the 'statistical' support of clades in tree topologies, this confidence seems to be unfounded. Contradictions between phylogenies based on different analyses are already a strong indication of unnoticed pitfalls. The use of tree-independent tools for exploratory analyses of data quality is highly recommended. Concerning the new mollusk phylogeny more convincing evidence is needed. PMID:19555513

  18. A mollusk retinoic acid receptor (RAR) ortholog sheds light on the evolution of ligand binding.

    PubMed

    Gutierrez-Mazariegos, Juliana; Nadendla, Eswar Kumar; Lima, Daniela; Pierzchalski, Keely; Jones, Jace W; Kane, Maureen; Nishikawa, Jun-Ichi; Hiromori, Youhei; Nakanishi, Tsuyoshi; Santos, Miguel M; Castro, L Filipe C; Bourguet, William; Schubert, Michael; Laudet, Vincent

    2014-11-01

    Nuclear receptors are transcription factors that regulate networks of target genes in response to small molecules. There is a strong bias in our knowledge of these receptors because they were mainly characterized in classical model organisms, mostly vertebrates. Therefore, the evolutionary origins of specific ligand-receptor couples still remain elusive. Here we present the identification and characterization of a retinoic acid receptor (RAR) from the mollusk Nucella lapillus (NlRAR). We show that this receptor specifically binds to DNA response elements organized in direct repeats as a heterodimer with retinoid X receptor. Surprisingly, we also find that NlRAR does not bind all-trans retinoic acid or any other retinoid we tested. Furthermore, NlRAR is unable to activate the transcription of reporter genes in response to stimulation by retinoids and to recruit coactivators in the presence of these compounds. Three-dimensional modeling of the ligand-binding domain of NlRAR reveals an overall structure that is similar to vertebrate RARs. However, in the ligand-binding pocket (LBP) of the mollusk receptor, the alteration of several residues interacting with the ligand has apparently led to an overall decrease in the strength of the interaction with the ligand. Accordingly, mutations of NlRAR at key positions within the LBP generate receptors that are responsive to retinoids. Altogether our data suggest that, in mollusks, RAR has lost its affinity for all-trans retinoic acid, highlighting the evolutionary plasticity of its LBP. When put in an evolutionary context, our results reveal new structural and functional features of nuclear receptors validated by millions of years of evolution that were impossible to reveal in model organisms. PMID:25116705

  19. A Mollusk Retinoic Acid Receptor (RAR) Ortholog Sheds Light on the Evolution of Ligand Binding

    PubMed Central

    Gutierrez-Mazariegos, Juliana; Nadendla, Eswar Kumar; Lima, Daniela; Pierzchalski, Keely; Jones, Jace W.; Kane, Maureen; Nishikawa, Jun-Ichi; Hiromori, Youhei; Nakanishi, Tsuyoshi; Santos, Miguel M.; Castro, L. Filipe C.; Bourguet, William

    2014-01-01

    Nuclear receptors are transcription factors that regulate networks of target genes in response to small molecules. There is a strong bias in our knowledge of these receptors because they were mainly characterized in classical model organisms, mostly vertebrates. Therefore, the evolutionary origins of specific ligand-receptor couples still remain elusive. Here we present the identification and characterization of a retinoic acid receptor (RAR) from the mollusk Nucella lapillus (NlRAR). We show that this receptor specifically binds to DNA response elements organized in direct repeats as a heterodimer with retinoid X receptor. Surprisingly, we also find that NlRAR does not bind all-trans retinoic acid or any other retinoid we tested. Furthermore, NlRAR is unable to activate the transcription of reporter genes in response to stimulation by retinoids and to recruit coactivators in the presence of these compounds. Three-dimensional modeling of the ligand-binding domain of NlRAR reveals an overall structure that is similar to vertebrate RARs. However, in the ligand-binding pocket (LBP) of the mollusk receptor, the alteration of several residues interacting with the ligand has apparently led to an overall decrease in the strength of the interaction with the ligand. Accordingly, mutations of NlRAR at key positions within the LBP generate receptors that are responsive to retinoids. Altogether our data suggest that, in mollusks, RAR has lost its affinity for all-trans retinoic acid, highlighting the evolutionary plasticity of its LBP. When put in an evolutionary context, our results reveal new structural and functional features of nuclear receptors validated by millions of years of evolution that were impossible to reveal in model organisms. PMID:25116705

  20. Cardiovascular effects of basal insulins.

    PubMed

    Mannucci, Edoardo; Giannini, Stefano; Dicembrini, Ilaria

    2015-01-01

    Basal insulin is an important component of treatment for both type 1 and type 2 diabetes. One of the principal aims of treatment in patients with diabetes is the prevention of diabetic complications, including cardiovascular disease. There is some evidence, although controversial, that attainment of good glycemic control reduces long-term cardiovascular risk in both type 1 and type 2 diabetes. The aim of this review is to provide an overview of the potential cardiovascular safety of the different available preparations of basal insulin. Current basal insulin (neutral protamine Hagedorn [NPH], or isophane) and basal insulin analogs (glargine, detemir, and the more recent degludec) differ essentially by various measures of pharmacokinetic and pharmacodynamic effects in the bloodstream, presence and persistence of peak action, and within-subject variability in the glucose-lowering response. The currently available data show that basal insulin analogs have a lower risk of hypoglycemia than NPH human insulin, in both type 1 and type 2 diabetes, then excluding additional harmful effects on the cardiovascular system mediated by activation of the adrenergic system. Given that no biological rationale for a possible difference in cardiovascular effect of basal insulins has been proposed so far, available meta-analyses of publicly disclosed randomized controlled trials do not show any signal of increased risk of major cardiovascular events between the different basal insulin analogs. However, the number of available cardiovascular events in these trials is very small, preventing any clear-cut conclusion. The results of an ongoing clinical trial comparing glargine and degludec with regard to cardiovascular safety will provide definitive evidence. PMID:26203281

  1. Cardiovascular effects of basal insulins

    PubMed Central

    Mannucci, Edoardo; Giannini, Stefano; Dicembrini, Ilaria

    2015-01-01

    Basal insulin is an important component of treatment for both type 1 and type 2 diabetes. One of the principal aims of treatment in patients with diabetes is the prevention of diabetic complications, including cardiovascular disease. There is some evidence, although controversial, that attainment of good glycemic control reduces long-term cardiovascular risk in both type 1 and type 2 diabetes. The aim of this review is to provide an overview of the potential cardiovascular safety of the different available preparations of basal insulin. Current basal insulin (neutral protamine Hagedorn [NPH], or isophane) and basal insulin analogs (glargine, detemir, and the more recent degludec) differ essentially by various measures of pharmacokinetic and pharmacodynamic effects in the bloodstream, presence and persistence of peak action, and within-subject variability in the glucose-lowering response. The currently available data show that basal insulin analogs have a lower risk of hypoglycemia than NPH human insulin, in both type 1 and type 2 diabetes, then excluding additional harmful effects on the cardiovascular system mediated by activation of the adrenergic system. Given that no biological rationale for a possible difference in cardiovascular effect of basal insulins has been proposed so far, available meta-analyses of publicly disclosed randomized controlled trials do not show any signal of increased risk of major cardiovascular events between the different basal insulin analogs. However, the number of available cardiovascular events in these trials is very small, preventing any clear-cut conclusion. The results of an ongoing clinical trial comparing glargine and degludec with regard to cardiovascular safety will provide definitive evidence. PMID:26203281

  2. Evaluation of tropical water sources and mollusks in southern Brazil using microbiological, biochemical, and chemical parameters.

    PubMed

    Souza, Doris Sobral Marques; Ramos, Ana Paula Dores; Nunes, Fabrício Flores; Moresco, Vanessa; Taniguchi, Satie; Leal, Diego Averaldo Guiguet; Sasaki, Silvio Tarou; Bícego, Márcia Caruso; Montone, Rosalinda Carmela; Durigan, Maurício; Teixeira, Adriano Luiz; Pilotto, Mariana Rangel; Delfino, Nicésio; Franco, Regina Maura Bueno; Melo, Cláudio Manoel Rodrigues de; Bainy, Afonso Celso Dias; Barardi, Célia Regina Monte

    2012-02-01

    Florianópolis, a city located in the Santa Catarina State in southern Brazil, is the national leading producer of bivalve mollusks. The quality of bivalve mollusks is closely related to the sanitary conditions of surrounding waters where they are cultivated. Presently, cultivation areas receive large amounts of effluents derived mainly from treated and non-treated domestic, rural, and urban sewage. This contributes to the contamination of mollusks with trace metals, pesticides, other organic compounds, and human pathogens such as viruses, bacteria, and protozoan. The aim of this study was to perform a thorough diagnosis of the shellfish growing areas in Florianópolis, on the coast of Santa Catarina. The contamination levels of seawater, sediments, and oysters were evaluated for their microbiological, biochemical, and chemical parameters at five sea sites in Florianópolis, namely three regular oyster cultivation areas (Sites 1, 2, and oyster supplier), a polluted site (Site 3), and a heavily polluted site (Site 4). Samples were evaluated at day zero and after 14 days. Seawater and sediment samples were collected just once, at the end of the experiment. Antioxidant defenses, which may occur in contaminated environments in response to the increased production of reactive oxygen species (ROS) by organisms, were analyzed in oysters, as well as organic compounds (in oysters and sediment samples) and microbiological contamination (in oysters and seawater samples). The results showed the presence of the following contaminants: fecal coliforms in seawater samples (four sites), human adenovirus (all sites), human noroviruses GI and GII (two sites), Hepatitis A viruses (one site), JC Polyomavirus in an oyster sample from the oyster supplier, Giardia duodenalis cysts, and Cryptosporidium sp oocysts (one site). Among organochlorine pesticides, only DDT (dichlorodiphenyltrichloroethane) and HCH (hexachlorocyclohexane) were detected in some sediment and oysters samples in very

  3. Hydrogen peroxide induces spawning in mollusks, with activation of prostaglandin endoperoxide synthetase.

    PubMed

    Morse, D E; Duncan, H; Hooker, N; Morse, A

    1977-04-15

    Addition of hydrogen peroxide to seawater causes synchronous spawning in gravid male and female abalones, and certain other mollusks as well. This effect is blocked by exposure of the animals to aspirin, an inhibitor of the enzyme catalyzing oxidative synthesis of prostaglandin endoperoxide. Hydrogen peroxide activates this enzymatic reaction in cell-free extracts prepared from abalone eggs (a very rich source of the prostaglandin endoperoxide synthetase); this effect appears to reveal a fundamental property of prostaglandin endoperoxide synthesis. Applicability of these findings to both mariculture and medical purposes is suggested. PMID:403609

  4. [Nutrition and biological value of food parts of a trade bivalve mollusk Anadara broughtoni].

    PubMed

    Tabakaeva, O V; Tabakaev, A V

    2015-01-01

    Currently, the human diet includes different new products of seafishing, including non-fish--bivalves and gastropods, holothurias, echinoderms, jellyfishes that demands careful studying of their chemical composition. The purpose of the study was to determine the nutritional and biological value of all soft parts of the burrowing bivalve MOLLUSK Anadara broughtoni from the Far East region. It was established thatfood parts of a bivalve were significantly flooded (water content--73.5-84.2%), with the minimum water content in the adductor and maximum in the mantle. Dry solids are presented by organic (89-93%) and mineral (7-11%) components. Organic components consist of protein (14.6-20.7%), lipids (1.8-2.3%), carbohydrates (2.1-2.6%). The analysis of amino-acid composition of proteins of food parts of the mollusk of Anadara broughtonishowed the presence of all essential amino acids with slight differences in their content depending on the localization of the protein. All edible parts have tryptophan as the limiting amino acid. Muscle proteins have maximum level of lysine, methionine, cysteine, phenylalanine and tyrosine; mantle proteins--leucine, isoleucine and threonine; adductor proteins--valine, phenylalanine, tyrosine, methionine and cysteine. Predominant nonessential amino acids forproteins of all food pieces are glycine, aspartic acid, glutamic acid, arginine. The coefficient of amino-acid score differences of adductor protein (31.7%) is less than the same of cloak by 3.7%. The indicator "biological value" is maximal for adductor (68.3%), but the differenceformuscle is only 0.83%. Mantle proteins are characterized by minimum biological value (64.6%). The coefficient of utility of amino acid composition of protein is maximalfor muscle (57.83%), and values for a cloak and an adductor differ slightly (55.81 and 55.96%). Taurine content in food parts of a mollusk Anadara broughtoni is rather high compared to with other bivalve mollusks of the Far East region

  5. [Risk-benefit of some mollusks and processed fishes in the renal patient's diet].

    PubMed

    Castro-González, M I; Miranda-Becerra, D; Pérez-Gil, R F

    2010-03-01

    The renal diet must include limited amounts of high quality protein, phosphorus P and potassium K. n-3 polyunsaturated fatty acids (n-3PUFA EPA and DHA), present in fishes and mollusks, render beneficial properties against progression of renal damage. The aim of this study was to evaluate protein PR, phosphorus P, potassium K, calcium Ca and n-3PUFA in processed fishes and mollusks as an alimentary option for renal patients. Canned tuna (water AA and oil AC), sardine in tomate sauce ST and chipotle SC and smoked salmon SA, fresh jumbo flying squid CA, common octopus PU and oyster OS were evaluated. Significant difference was detected (p <.0.05) for K between different types of fish. SA contained 38g/100g PR, 307 mg/100g of P, 371 mg/ 100g K and 106 mg/100g n-3PUFA. Sardines contained (279-304 mg/100g of P and 283-322 mg/100g K and tunas 142-160 mg/100g P and 141-154 mg/100g K. Tunas and sardines had elevated concentration of n-3PUFA (4114 and 4790 mg/ 100g respectively), P:n-3PUFA and K:n-3PUFA ratio was low in tunas (0.03) and sardines (0.06). AA and AC contained (10.1 and 11.1 mgP/gPR), while ST and SC provided 26.4-19.1 mg/P/gPR. n-3PUFA/gPR were similar for tunas and sardines (302-424mg/gPR). Mollusks: CA presented the highest values of P and PR (2.4 mg/100g and 18.4g/100g). n-3PUFA ranged from 4.3 to 79 mg/100g in PU and OS respectively. Among processed fishes, only canned tunas are recommended for the diet of renal patients, in an individualized basis. The risk-benefit ratio of sardines in the renal diet should be evaluated, due to their high content of P and n-3PUFA. Salmon and mollusks are not recommended for the renal diet. PMID:21090278

  6. [Variable magnetic field of 8 Hz corrects the opioid system activity in mollusks behind the ferromagnetic screening].

    PubMed

    Temur'iants, N A; Kostiuk, A S

    2014-01-01

    The three phases of mollusk nociception alteration as a result of extended ferromagnetic screening combined with exposure to a variable magnetic field of 8 Hz correlated with phase changes in the opioid system activity (OSA) deduced from the naloxone action on the thermal avoidance response. On phase I, OSA inactivation was inhibited and, consequently, hyperalgesia progression was expedited. On phase II, OSA rose so that naloxone annulled completely the antinociceptive effect produced by the ferromagnetic screening. On phase III, OSA declined progressively, as naloxone merely reduced the antinociceptive effect because of apparently, growing OSA tolerance to the ferromagnetic screening. Phase I was absent when mollusks were exposed to the ferromagnetic screening and variable magnetic field; however, OSA changes on phases II and III were present. It was concluded that the variable magnetic field of 8 Hz can be used for correcting changes in the opioid system activity in mollusks behind the ferromagnetic screening. PMID:25163338

  7. Multiple pigmented basal cell carcinomas.

    PubMed

    Shoji, T; Lee, J; Hong, S H; Oh, C H; Kim, W K; Bhawan, J

    1998-04-01

    Basal cell carcinoma is the most common of all skin cancers and the most prevalent one among Caucasians. Rarely, these tumors are seen in other races. We report a 77-year-old Korean woman who presented with multiple darkly pigmented enlarging nodules on her scalp, face, trunk, and extremities. The patient had first noted a 6-mm pigmented lesion on her left eyebrow 10 years previously. Since then, other lesions had appeared in many locations on her body. She had been otherwise healthy and without a history of exposure to arsenic or radiation. There was no family history of skin cancer, xeroderma pigmentosum, or basal cell nevus syndrome. On physical examination, multiple darkly pigmented dome-shaped papules and nodules were present on her scalp, face, right forearm, lower abdomen, and inguinal areas. They ranged in size from 0.5 mm to 2 cm. The larger ones showed central ulceration. Multiple biopsy specimens from different sites showed pigmented basal cell carcinomas. Clinically, there was no evidence of nevus sebaceus, xeroderma pigmentosum, basal cell nevus syndrome, or immunodeficiency. Clinical workup including chest radiography, abdominal ultrasound, bone scan, and brain computerized axial tomography scan did not demonstrate primary or secondary tumors. The results of serologic and hematologic tests were also within normal limits. This is an unusual case report of multiple pigmented basal cell carcinomas in an Asian woman without any predisposing risk factors. PMID:9557792

  8. Improved molecular detection of Angiostrongylus cantonensis in mollusks and other environmental samples with a species-specific ITS1-based TaqMan assay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Angiostrongylus cantonensis is the most common cause of human eosinophilic meningitis. Humans can become infected by ingesting food items contaminated with the third-stage infectious larvae released from infected mollusks as well as by ingesting mollusks or paratenic hosts carrying the infectious st...

  9. Development of a loop-mediated isothermal amplification method for detection of Perkinsus spp. in mollusks.

    PubMed

    Feng, Chunyan; Wang, Caixia; Lin, Xiangmei; Zhang, Yongning; Lv, Jizhou; Deng, Junhua; Yuan, Xiangfen; Mei, Lin; Wu, Shaoqiang

    2013-05-27

    Perkinsus is a genus of unicellular protozoan parasite responsible for mass mortality of several commercially valuable mollusks. Surveillance and inspection of its epidemiology in the field calls for convenient and rapid detection methods. Here, a loop-mediated isothermal amplification (LAMP) assay was developed to detect the presence of Perkinsus spp. in mollusks. Specific LAMP primers were designed targeting the conserved internal transcribed spacer 2 (ITS-2) region of the rRNA gene of Perkinsus spp. Using ITS-2 recombinant plasmid as a template, we optimized the LAMP reaction system and conditions and then evaluated the analytical sensitivity and specificity of the assay. The LAMP assay was validated using clam samples collected from coastal areas in eastern China and oysters imported to China and compared with the traditional Ray's fluid thioglycollate culture method (RFTM). Our results showed that the LAMP detection method for Perkinsus was successful. The detection limit was 10 copies of plasmid DNA. Compared to the RFTM assay, the LAMP detection method was more sensitive (56 versus 52 positive out of 60 samples). P. olseni and P. marinus from infected hosts were successfully detected by this method. The LAMP method is rapid, sensitive, and specific for Perkinsus spp. detection, and could be used to screen for perkinsosis both on farms and at ports. PMID:23709467

  10. Kahalalides V–Y Isolated from a Hawaiian Collection of the Sacoglossan Mollusk Elysia rufescens

    PubMed Central

    Rao, Karumanchi V.; Na, MinKyun; Cook, Jennifer C.; Peng, Jiangnan; Matsumoto, Rae; Hamann, Mark T.

    2016-01-01

    Four new kahalalides, V (1), W (2), X (3), and Y (4), as well as six previously characterized kahalalides have been isolated from a two-year collection of the sacoglossan mollusk Elysia rufescens. Curiously, kahalalide B, previously isolated in high yield from E. rufescens, was found to be essentially absent from these collections despite identical collection sites and times with previous collections. In addition, kahalalide K, which to date has only been reported from Bryopsis sp., was found in this collection of E. rufescens, suggesting that the production of these metabolites could potentially be from a microbial association with the mollusk and algae, and this relationship is continuously evolving in response to changes in the environment and predation. The structures of new peptides have been established on the basis of extensive 1D and 2D NMR spectroscopic data analysis. Kahalalide V (1) was ascertained to be an acyclic derivative of kahalalide D (5), while kahalalide W (2) was determined to have a 4-hydroxy-L-proline residue instead of the proline in 5. The arginine residue of kahalalide X (3), an acyclic derivative of kahalalide C, was determined to have an L configuration. Kahalalide Y (4) was found to have an L-proline residue instead of the hydroxyproline in kahalalide K. It is clear from this collection of E. rufescens that the discovery of new kahalalide-related metabolites is still highly feasible. PMID:18407693

  11. Mobile Element Evolution Playing Jigsaw—SINEs in Gastropod and Bivalve Mollusks

    PubMed Central

    Matetovici, Irina; Sajgo, Szilard; Ianc, Bianca; Ochis, Cornelia; Bulzu, Paul; Popescu, Octavian; Damert, Annette

    2016-01-01

    SINEs (Short INterspersed Elements) are widely distributed among eukaryotes. Some SINE families are organized in superfamilies characterized by a shared central domain. These central domains are conserved across species, classes, and even phyla. Here we report the identification of two novel such superfamilies in the genomes of gastropod and bivalve mollusks. The central conserved domain of the first superfamily is present in SINEs in Caenogastropoda and Vetigastropoda as well as in all four subclasses of Bivalvia. We designated the domain MESC (Romanian for MElc—snail and SCoica—mussel) because it appears to be restricted to snails and mussels. The second superfamily is restricted to Caenogastropoda. Its central conserved domain—Snail—is related to the Nin-DC domain. Furthermore, we provide evidence that a 40-bp subdomain of the SINE V-domain is conserved in SINEs in mollusks and arthropods. It is predicted to form a stable stem-loop structure that is preserved in the context of the overall SINE RNA secondary structure in invertebrates. Our analysis also recovered short retrotransposons with a Long INterspersed Element (LINE)-derived 5′ end. These share the body and/or the tail with transfer RNA (tRNA)-derived SINEs within and across species. Finally, we identified CORE SINEs in gastropods and bivalves—extending the distribution range of this superfamily. PMID:26739168

  12. Mobile Element Evolution Playing Jigsaw - SINEs in Gastropod and Bivalve Mollusks.

    PubMed

    Matetovici, Irina; Sajgo, Szilard; Ianc, Bianca; Ochis, Cornelia; Bulzu, Paul; Popescu, Octavian; Damert, Annette

    2016-01-01

    SINEs (Short INterspersed Elements) are widely distributed among eukaryotes. Some SINE families are organized in superfamilies characterized by a shared central domain. These central domains are conserved across species, classes, and even phyla. Here we report the identification of two novel such superfamilies in the genomes of gastropod and bivalve mollusks. The central conserved domain of the first superfamily is present in SINEs in Caenogastropoda and Vetigastropoda as well as in all four subclasses of Bivalvia. We designated the domain MESC (Romanian for MElc-snail and SCoica-mussel) because it appears to be restricted to snails and mussels. The second superfamily is restricted to Caenogastropoda. Its central conserved domain-Snail-is related to the Nin-DC domain. Furthermore, we provide evidence that a 40-bp subdomain of the SINE V-domain is conserved in SINEs in mollusks and arthropods. It is predicted to form a stable stem-loop structure that is preserved in the context of the overall SINE RNA secondary structure in invertebrates. Our analysis also recovered short retrotransposons with a Long INterspersed Element (LINE)-derived 5' end. These share the body and/or the tail with transfer RNA (tRNA)-derived SINEs within and across species. Finally, we identified CORE SINEs in gastropods and bivalves-extending the distribution range of this superfamily. PMID:26739168

  13. Baseline trace metals in seagrass, algae, and mollusks in a southern Tyrrhenian ecosystem (Linosa Island, Sicily).

    PubMed

    Conti, Marcelo Enrique; Bocca, Beatrice; Iacobucci, Marta; Finoia, Maria Grazia; Mecozzi, Mauro; Pino, Anna; Alimonti, Alessandro

    2010-01-01

    Trace elements were analyzed in organisms collected at five sampling stations along coastal areas of Linosa Island, Sicily (southern Tyrrhenian Sea, Italy). Concentrations of Cd, Cr, Cu, Pb, and Zn were measured in Posidonia oceanica L. Delile tissues, the two brown algae Padina pavonica (L.) Thivy and Cystoseira sp., and the two gastropod mollusks Monodonta turbinata Born and Patella caerulea L. Seawater samples were also collected at each site to assess soluble metal concentrations and to gain relevant information on their bioaccumulation ability. Data were processed by multivariate techniques, such as principal component analysis (PCA) and linear discriminant analysis on PCA factors. The scoreplots obtained showed that the pollutant distribution is more significantly correlated with species than with sites. For seaweeds, P. oceanica was associated with higher Cd, Cu, and Zn levels; Padina species had higher Cr concentrations, and Cystoseira had higher Pb levels. For mollusks, Monodonta species had high concentrations of Cu and Cr and Patella species were associated with Cd. Some general metal bioaccumulation patterns are described but no one sampling site was more contaminated than the others. The hypothesis of Linosa island serving as a reference ecosystem for baseline trace metal levels in southern Tyrrhenian areas is indeed supported by the statistical comparison among other southern Tyrrhenian ecosystems performed with Kruskall Wallis and Mann-Whitney tests. For P. oceanica leaves, P. pavonica, M. turbinata, and P. caerulea, this study confirms their usefulness as possible cosmopolitan biomonitors of trace metals in marine Mediterranean areas. PMID:19458990

  14. Experimental analysis and numerical modeling of mollusk shells as a three dimensional integrated volume.

    PubMed

    Faghih Shojaei, M; Mohammadi, V; Rajabi, H; Darvizeh, A

    2012-12-01

    In this paper, a new numerical technique is presented to accurately model the geometrical and mechanical features of mollusk shells as a three dimensional (3D) integrated volume. For this purpose, the Newton method is used to solve the nonlinear equations of shell surfaces. The points of intersection on the shell surface are identified and the extra interior parts are removed. Meshing process is accomplished with respect to the coordinate of each point of intersection. The final 3D generated mesh models perfectly describe the spatial configuration of the mollusk shells. Moreover, the computational model perfectly matches with the actual interior geometry of the shells as well as their exterior architecture. The direct generation technique is employed to generate a 3D finite element (FE) model in ANSYS 11. X-ray images are taken to show the close similarity of the interior geometry of the models and the actual samples. A scanning electron microscope (SEM) is used to provide information on the microstructure of the shells. In addition, a set of compression tests were performed on gastropod shell specimens to obtain their ultimate compressive strength. A close agreement between experimental data and the relevant numerical results is demonstrated. PMID:23137621

  15. [Diversity and abundance of mollusks in the sublittoral epifaunal community of Punta Patilla, Venezuela].

    PubMed

    Prieto, Antulio; Ruiz, Lilia J; García, Natividad

    2005-01-01

    The diversity of a sublittoral epifaunal mollusk community of Punta Patilla, Sucre State, Venezuela, was studied from September 1990 to September 1991. We identified 25 species (14 bivalves and 11 gastropods) of mollusks that inhabit gravel, soft sand and bottoms covered by Thalassia testudinum. Total diversity indices were H' = 3.42. J' = 0.74 and 1-D = 0.85. Monthly diversity reached its maximum in March 1991 (3.12 bits/ ind.), June 1991 (2.88 bits/ind.) and September 1991 (2.95 bits/ind.); minimum diversity was recorded in August 1991 (1.20 bits/ind.). A log series model showed a diversity index alpha = 4.56 for species abundance data and alpha = 3.11 for biomass data. The more abundant species were Chione cancellata, Anigona listeri, Chione granulata and Area zebra among the bivalves, and Chicoreus brevifrons, Turritella variegata and Phllonotus pomum among the gastropods (which present maximum biomass). The average total biomass (56.80 g/m2) is low when compared to reports from other tropical zones. PMID:17354426

  16. Aliens in Paradise. Boat density and exotic coastal mollusks in Moorea Island (French Polynesia).

    PubMed

    Ardura, Alba; Planes, Serge; Garcia-Vazquez, Eva

    2015-12-01

    Pacific islands are particularly vulnerable to the effects of invasive species. After habitat destruction or modification, invasive species are responsible for more biological extinctions than any other cause. Further, the rate of extinction of native species has been higher on islands than anywhere else in the world. Invasive species have also degraded native ecosystems. In order to detect exotic intertidal mollusk species, an extensive sampling around Moorea Island, a more or less unspoiled island surrounded by a rich coral reef habitat, has been developed considering that sampled points have different characteristics in wave exposure, algae coverage, type of substrate, distance to ports, distance to freshwater, distance sewage and boat traffic. Samples were DNA barcoded for unequivocal species assignation. The presence of five NIS among 26 species seems an important signal of introduction of alien biota in Moorea Island coast. However they were represented by a total of 38 individuals among 1487 mollusks (2.55%). While the distance to relatively big ports influenced directly species richness, the intensity of maritime traffic measured as boat density near sampling points was significantly associated with the frequency of exotic species. Other environmental factors did not show significant correlation with the frequency of exotics, suggesting that in an environment without big discontinuities, with little habitat modification, local boat traffic is the most influential factor in the spread of exotic species. This could be mitigated relatively easily by reducing boat density in local zones of ecological interest. PMID:26364683

  17. Baseline trace metals in gastropod mollusks from the Beagle Channel, Tierra del Fuego (Patagonia, Argentina).

    PubMed

    Conti, Marcelo Enrique; Stripeikis, Jorge; Finoia, Maria Grazia; Tudino, Mabel Beatriz

    2012-05-01

    With the aim to evaluate the mollusk Nacella (P)magellanica as biomonitor of elemental pollution in seawater of the Beagle Channel, more than one hundred individuals of the gastropod were sampled, separated in viscera and muscle, and then examined with respect to the accumulation of Cd, Cr, Cu, Ni, Pb and Zn. Collection was performed in seven strategic locations along 170 km of the coastal area of the Beagle Channel (Tierra del Fuego, Argentina) in two campaigns during 2005 and 2007. Samples of surrounding seawater in the different sites were obtained and tested for the same metals as well. The accumulation capacity of Nacella (P)magellanica and thus its aptitude as biomonitor, was evaluated through the calculus of the preconcentration factors of the metals assayed. A discussion involving the comparison with other mollusks previously tested will be given. Several statistical approaches able to analyze data with environmental purposes were applied. Non parametric univariate tests such as Kruskal-Wallis and Mann-Whitney were carried out to assess the changes of the metal concentrations with time (2005 and 2007) in each location. Multivariate methods (linear discriminant analysis on PCA factors) were also applied to obtain a more reliable site classification. Johnson's probabilistic method was carried out for comparison between different geographical areas. The possibility of employing these results as heavy metals' background levels of seawater from the Beagle Channel will be debated. PMID:22350107

  18. The first mollusk spätzle homolog gene in the clam, Paphia undulate.

    PubMed

    Yu, Mingjia; Zhang, Yuehuan; Tang, Xu; Ren, Jun; Zhang, Yang

    2015-12-01

    Spätzle, is the only identified endogenous Toll receptor ligand, plays a critical role in initiatinge innate immune responses and controlling dorsal-ventral axis formation in Drosophila. Here we identified the first spätzle gene homolog, Pu-Spz, in the marine mollusk Paphia undulate. The full-length of Pu-Spz cDNA is 1248 bp, including an open reading frame (ORF) of 702 bp, a 5'-untranslated region (UTR) of 26 bp and a 3'-UTR of 203 bp. The ORF encodes a 233-amino-acid protein with conserved domains; it includes a putative signal peptide and a C-terminal cystine-knot. Sequence alignment revealed that the cystine-knot domain of Pu-Spz contains six highly conserved Cys residues, which maintain a molecular conformation suitable for Toll receptor binding. Unlike Spätzle, Pu-Spz lacks a seventh Cys residue, which is essential for forming intermolecular disulfide bridge. Phylogenetic analysis revealed that Pu-Spz is closer to the homologs found in crustaceans than to those in the insect branch. Transcript abundance of Pu-Spz was increased after challenging P. undulate with either heat-killed Listeria monocytogenes or heat-killed Vibrio alginolyticus, suggesting Spätzle is involved in P. undulate host defense. Our results demonstrate convergent evolution of the spätzle-Toll system between the mollusk and arthropod lineages. PMID:26477575

  19. Basal cell carcinoma – diagnosis

    PubMed Central

    Bowszyc-Dmochowska, Monika; Strzelecka-Węklar, Daria; Dańczak-Pazdrowska, Aleksandra; Adamski, Zygmunt

    2013-01-01

    Basal cell carcinoma is the most common skin cancer in the Caucasian population. The cancer arises in sun exposed areas of the skin. The incidence of morbidity is high and it is still growing. The metastatic rate is low, but the enlarging tumor may cause severe tissue disfigurement and a poor cosmetic outcome. The diagnosis is usually clinical but there are many subtypes of this carcinoma and correct diagnosis is the clue to appropriate treatment of the lesion. The main problem in basal cell carcinoma management is the high recurrence rate. PMID:24592119

  20. Teachers Reflect Standards in Basals

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2012-01-01

    Dozens of teachers and literacy specialists from across the country hunkered down in Baltimore at round tables, with laptops, pens, and paper, intent on rewriting the collections that wield tremendous influence over the way millions of U.S. children learn literacy skills: the big-name basal readers. Hailing from 18 school districts in 11 states,…

  1. [Evolutionary regularities of somatic polyploidy expansion in salivary glands of gastropod mollusks. V. Subclasses Opisthobranchia and Pulmonata].

    PubMed

    Anisimov, A P; Ziumchenko, N E

    2012-01-01

    Salivary glands of 25 species of euthyneural gastropod mollusks (Opisthobranchia and Pulmonata) have been investigated by means of histochemical methods and DNA cytophotometry in nuclei of cells. The cells of three basic types are distinguished in glandular epithelim: granular cells (with glicoproteid granular inclusions), mucocytes-I (with sulfatic acid mucopolysaccharides) and mucocytes-II (with neutral and acid nonsulfatic polysaccharides and proteins) and so the epithelial ciliated cells and cells of the ducts. It was shown that glandular cells of salivary glands of all discovered mollusks' species are polyploid in different degree. The highest ploidy level estimated by means of DNA content in most of species is 64-128c. The giant polyploidy, attained to 4096c, is discovered in cells of salivary glands of Tritonia diomedea. The functional conditionality connected with features of feeding of different mollusk species and phylogenetic tendencies of expansion of somatic polyploidy in class Gastropoda are discussed. In comparison with allogenic, facultative and small polyploidy manifestation in Prosobranchia the obligatory polyploidization of high degree revealed in cells of salivary glands of Opisthobranchia and Pulmonata is consider to be the original cytological arogenesis. The probable causes of such differences are conneted with euthyneural type of organization of central nervous system and giant polyploidy of neurons in Opisthobranchia and Pulmonata mollusks. The causes, mechanisms and significance of such correlations are unclear for the present. PMID:22590930

  2. [Isolation of the cercaria Diplostomum phoxini (Faust, 1918) Arvy et Buttner, 1954 (Diplostomatidae) from fresh water mollusks of the Crimea].

    PubMed

    Sten'ko, R P

    1976-01-01

    Data on the biology and morphology of cercariae of Diplostomum phoxini (Faust, 1918) Arvy et Buttner, 1954 are given. The cercariae were found in Radix auricularia from the middle part of the Burulcha river (Ukranian SSR, Crimea). In November, 1974 the invasion extensity of mollusks was 16.3%. No cercariae were found in spring and summer samples. PMID:66655

  3. Vestigial prototroch in a basal nemertean, Carinoma tremaphoros (Nemertea; Palaeonemertea).

    PubMed

    Maslakova, S A; Martindale, M Q; Norenburg, J L

    2004-01-01

    Nemerteans have been alleged to belong to a protostome clade called the Trochozoa that includes mollusks, annelids, sipunculids, echiurids, and kamptozoans and is characterized by, among other things, the trochophore larva. The trochophore possesses a prototroch, a preoral belt of specialized ciliary cells, derived from the trochoblast cells. Nemertea is the only trochozoan phylum for which presence of the trochophore larva possessing a prototroch had never been shown. However, so little is known about nemertean larval development that comparing it with development of other trochozoans is difficult. Development in the nemertean clade Pilidiophora is via a highly specialized planktonic larva, the pilidium, and most of the larval body is lost during a drastic metamorphosis. Other nemerteans (hoplonemerteans and palaeonemerteans) lack a pilidium, and their development is direct, forming either an encapsulated or planktonic "planuliform" larva, producing a juvenile without a dramatic change in body plan. We show that early in the development of a member of a basal nemertean assemblage, the palaeonemertean Carinoma tremaphoros, large squamous cells cover the entire larval surface except for the apical and posterior regions. Although apical and posterior cells continue to divide, the large surface cells cleavage arrest and form a contorted preoral belt. Based on its position, cell lineage, and fate, we suggest that this belt corresponds to the prototroch of other trochozoans. Lack of differential ciliation obscures the presence of the prototroch in Carinoma, but differentiation of the trochoblasts is clearly manifested in their permanent cleavage arrest and ultimate degenerative fate. Our results allow a meaningful comparison between the development of nemerteans and other trochozoans. We review previous hypotheses of the evolution of nemertean development and suggest that a trochophore-like larva is plesiomorphic for nemerteans while a pilidium type of development with

  4. Radiocarbon dating of fossil mollusk shells in the Yucca Mountain region

    SciTech Connect

    Brennan, R.; Quade, J.

    1995-12-01

    Fossil mollusk shells from late Quaternary deposits in Southern Nevada were radiocarbon dated to determine the age of paleogroundwater discharge events and to establish minimum {sup 14}C ages of paleogroundwater. Shells of the terrestrial taxa Vallonia sp. and Succineidae returned {sup 14}C dates consistent with those on organic material in the same stratigraphic position. The aquatic taxa Gyraulus parvus and Gyraulus circumstratus returned the oldest dates within each unit samples. These results show that (1) fossil Vallonia and Succineidae are useful in dating deposits in which no other radiocarbon-datable material is available, and (2) Gyraulus sp. select micro habitats with the most {sup 14}C deficient water, providing minimum ages of groundwater in the area during the last glacial period.

  5. Uptake of polycyclic aromatic hydrocarbon compounds by the gills of the bivalve mollusk Elliptio complanata.

    PubMed

    Birdsall, K; Kukor, J J; Cheney, M A

    2001-02-01

    Polycyclic aromatic hydrocarbons (PAHs) and herbicides are important contaminants of world water systems with effects on aquatic organisms. The uptake of naphthalene, anthracene, and chrysene by gills of the bivalve mollusk Elliptio complanata was determined. Additionally, the effects of paraquat, atrazine, alachlor, 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4-dinitrophenol on the uptake of these compounds were also determined. The results indicate (1) the uptake of anthracene is approximately equivalent to that of chrysene and the uptake of either of these compounds is higher than that of naphthalene; (2) comparisons of uptakes with that of inulin, which occupies only extracellular space, show that all compounds studied are taken up; (3) the uptakes of naphthalene, anthracene, and chrysene are initially altered by the presence of herbicides such as paraquat, alachlor, 2,4-D, atrazine, and 2,4-dinitrophenol. PMID:11351430

  6. Activated Acinus boosts basal autophagy

    PubMed Central

    Nandi, Nilay; Tyra, Lauren K; Krämer, Helmut

    2015-01-01

    Acinus (Acn) is a nuclear protein that participates in the regulation of autophagy. Loss of Acn function prevents autophagy in starving cells. Conversely, Acn activation induces basal autophagy. This enhances the quality control functions of autophagy such as the removal of misfolded proteins, thereby reducing neurodegeneration and prolonging lifespan. Acn activity is enhanced by Akt1-mediated phosphorylation, which counteracts the cleavage of Acn by a caspase-3 homolog. PMID:27308482

  7. Hox and ParaHox gene expression in early body plan patterning of polyplacophoran mollusks.

    PubMed

    Fritsch, Martin; Wollesen, Tim; Wanninger, Andreas

    2016-03-01

    Molecular developmental studies of various bilaterians have shown that the identity of the anteroposterior body axis is controlled by Hox and ParaHox genes. Detailed Hox and ParaHox gene expression data are available for conchiferan mollusks, such as gastropods (snails and slugs) and cephalopods (squids and octopuses), whereas information on the putative conchiferan sister group, Aculifera, is still scarce (but see Fritsch et al., 2015 on Hox gene expression in the polyplacophoran Acanthochitona crinita). In contrast to gastropods and cephalopods, the Hox genes in polyplacophorans are expressed in an anteroposterior sequence similar to the condition in annelids and other bilaterians. Here, we present the expression patterns of the Hox genes Lox5, Lox4, and Lox2, together with the ParaHox gene caudal (Cdx) in the polyplacophoran A. crinita. To localize Hox and ParaHox gene transcription products, we also investigated the expression patterns of the genes FMRF and Elav, and the development of the nervous system. Similar to the other Hox genes, all three Acr-Lox genes are expressed in an anteroposterior sequence. Transcripts of Acr-Cdx are seemingly present in the forming hindgut at the posterior end. The expression patterns of both the central class Acr-Lox genes and the Acr-Cdx gene are strikingly similar to those in annelids and nemerteans. In Polyplacophora, the expression patterns of the Hox and ParaHox genes seem to be evolutionarily highly conserved, while in conchiferan mollusks these genes are co-opted into novel functions that might have led to evolutionary novelties, at least in gastropods and cephalopods. PMID:27098677

  8. Hox and ParaHox gene expression in early body plan patterning of polyplacophoran mollusks

    PubMed Central

    Fritsch, Martin; Wollesen, Tim

    2016-01-01

    ABSTRACT Molecular developmental studies of various bilaterians have shown that the identity of the anteroposterior body axis is controlled by Hox and ParaHox genes. Detailed Hox and ParaHox gene expression data are available for conchiferan mollusks, such as gastropods (snails and slugs) and cephalopods (squids and octopuses), whereas information on the putative conchiferan sister group, Aculifera, is still scarce (but see Fritsch et al., 2015 on Hox gene expression in the polyplacophoran Acanthochitona crinita). In contrast to gastropods and cephalopods, the Hox genes in polyplacophorans are expressed in an anteroposterior sequence similar to the condition in annelids and other bilaterians. Here, we present the expression patterns of the Hox genes Lox5, Lox4, and Lox2, together with the ParaHox gene caudal (Cdx) in the polyplacophoran A. crinita. To localize Hox and ParaHox gene transcription products, we also investigated the expression patterns of the genes FMRF and Elav, and the development of the nervous system. Similar to the other Hox genes, all three Acr‐Lox genes are expressed in an anteroposterior sequence. Transcripts of Acr‐Cdx are seemingly present in the forming hindgut at the posterior end. The expression patterns of both the central class Acr‐Lox genes and the Acr‐Cdx gene are strikingly similar to those in annelids and nemerteans. In Polyplacophora, the expression patterns of the Hox and ParaHox genes seem to be evolutionarily highly conserved, while in conchiferan mollusks these genes are co‐opted into novel functions that might have led to evolutionary novelties, at least in gastropods and cephalopods. PMID:27098677

  9. Basal body structure in Trichonympha.

    PubMed

    Guichard, Paul; Gönczy, Pierre

    2016-01-01

    Trichonympha is a symbiotic flagellate of many species of termites and of the wood-feeding cockroach. Remarkably, this unicellular organism harbors up to over ten thousand flagella on its surface, which serve to propel it through the viscous environment of the host hindgut. In the 1960s, analysis of resin-embedded Trichonympha samples by electron microscopy revealed that the basal bodies that give rise to these flagella are exceptionally long, with a proximal, cartwheel-bearing, region some 50 times longer than that of regular centrioles. In recent years, this salient feature has prompted the analysis of the 3D architecture of Trichonympha basal bodies in the native state using cryo-electron tomography. The resulting ~40 Å resolution map of the basal body proximal region revealed a number of novel features that may be conserved in centrioles of other systems. These include proximal-distal polarity of the pinhead structure that links the cartwheel to centriolar microtubules, as well as of the linker between the A and the C microtubules. Moreover, this work demonstrated that the cartwheel is made of stacked ring-like structures that likely each comprise 18 molecules of SAS-6 proteins. PMID:26937279

  10. Discourse Types in Canadian Basal Reading Programs.

    ERIC Educational Resources Information Center

    Murphy, Sharon

    This study examined the authorship and discourse types of Canadian basal anthologies to determine whether the lingering centrality of the basal anthology in Canadian programs controls students and teachers by controlling language and reading. Each selection within five Canadian basal series (Gage Expressways II, Ginn Journeys, Holt Impressions,…

  11. Late miocene-pliocene paleoclimatic evolution documented by terrestrial mollusk populations in the western Chinese Loess Plateau.

    PubMed

    Li, Fengjiang; Wu, Naiqin; Rousseau, Denis-Didier; Dong, Yajie; Zhang, Dan; Pei, Yunpeng

    2014-01-01

    The Neogene eolian deposits in the Chinese Loess Plateau (CLP) are one of the most useful continental deposits for understanding climatic changes. To decipher Late Neogene paleoclimatic changes in the CLP, we present a terrestrial mollusk record spanning the time interval between 7.1 and 3.5 Ma from the western CLP. The results indicate four stages of paleoclimatic evolution: From 7.1 to 6.2 Ma, cold and dry climatic conditions prevailed as evidenced by high values of the total number of cold-aridiphilous (CA) mollusk species and by low values of all of the thermo-humidiphilous (TH) mollusk indices. From 6.2 to 5.4 Ma, the climate remained cold and dry but was not quite as dry as during the preceding phase, as indicated by the dominance of CA mollusks and more TH species and individuals. From 5.4 to 4.4 Ma, a warm and moist climate prevailed, as indicated by high values of the TH species and individuals and by the sparsity of CA species and individuals. From 4.4 to 3.5 Ma, all of the CA indices increased significantly and maintained high values; all of the TH indices exhibit high values from 4.4 to 4.0 Ma, an abrupt decrease from 4.0 Ma and a further increase from 3.7 Ma. The CA species of Cathaica pulveraticula, Cathaica schensiensis, and Pupopsis retrodens are only identified in this stage, indicating that the CA species were diversified and that the climate was becoming drier. Moreover, the CA mollusk group exhibits considerable diversity from 7.1 to 5.4 Ma when a cold, dry climate prevailed; whereas the diversity of the TH group was high during the relatively warm, wet interval from 5.4 to 4.4 Ma. This indicates that variations in the diversity of the CA and TH mollusk groups were closely related to climatic changes during the Late Miocene to Pliocene. PMID:24752586

  12. Late Miocene–Pliocene Paleoclimatic Evolution Documented by Terrestrial Mollusk Populations in the Western Chinese Loess Plateau

    PubMed Central

    Li, Fengjiang; Wu, Naiqin; Rousseau, Denis-Didier; Dong, Yajie; Zhang, Dan; Pei, Yunpeng

    2014-01-01

    The Neogene eolian deposits in the Chinese Loess Plateau (CLP) are one of the most useful continental deposits for understanding climatic changes. To decipher Late Neogene paleoclimatic changes in the CLP, we present a terrestrial mollusk record spanning the time interval between 7.1 and 3.5 Ma from the western CLP. The results indicate four stages of paleoclimatic evolution: From 7.1 to 6.2 Ma, cold and dry climatic conditions prevailed as evidenced by high values of the total number of cold-aridiphilous (CA) mollusk species and by low values of all of the thermo-humidiphilous (TH) mollusk indices. From 6.2 to 5.4 Ma, the climate remained cold and dry but was not quite as dry as during the preceding phase, as indicated by the dominance of CA mollusks and more TH species and individuals. From 5.4 to 4.4 Ma, a warm and moist climate prevailed, as indicated by high values of the TH species and individuals and by the sparsity of CA species and individuals. From 4.4 to 3.5 Ma, all of the CA indices increased significantly and maintained high values; all of the TH indices exhibit high values from 4.4 to 4.0 Ma, an abrupt decrease from 4.0 Ma and a further increase from 3.7 Ma. The CA species of Cathaica pulveraticula, Cathaica schensiensis, and Pupopsis retrodens are only identified in this stage, indicating that the CA species were diversified and that the climate was becoming drier. Moreover, the CA mollusk group exhibits considerable diversity from 7.1 to 5.4 Ma when a cold, dry climate prevailed; whereas the diversity of the TH group was high during the relatively warm, wet interval from 5.4 to 4.4 Ma. This indicates that variations in the diversity of the CA and TH mollusk groups were closely related to climatic changes during the Late Miocene to Pliocene. PMID:24752586

  13. "Basal Cell Blanche": A Diagnostic Maneuver to Increase Early Detection of Basal Cell Carcinomas.

    PubMed

    Quach, Olivia Leigh; Barry, Megan; Roberts Cruse, Allison; Wilson, Barbara B

    2016-01-01

    Basal cell carcinomas represent one of the most common skin cancers and often present initially in the primary care setting. Subtle basal cell carcinomas may be difficult to detect, and early detection of these carcinomas remains important in limiting patient morbidity. In this article, we present a simple diagnostic maneuver, "basal cell blanche," to increase early detection of basal cell carcinomas. PMID:27170799

  14. [The influence of the degree of infestation with trematode parthenites on the structure of penial glands in the mollusks Littorina saxatilis of different age].

    PubMed

    Ganzha, E V; Starunova, Z I

    2011-01-01

    Histological and confocal microscopy studies of the structure of penial glands in the Littorina saxatilis males were carried out. The examined mollusks belong to two age groups and were at different stages of spontaneous infection with a trematode from the pygmaeus species group (Microphallus piriformes). Based on comparative analysis of microscopic sections of copulative organs in infested and non-infested mollusks, data on the modifications in histological structure ofpenial glands were obtained. From these data we can suggest that the infestation have an influence on all parts of the gland. Decrease of secret production and reduction of muscular capsule (down to its disappearance) were observed. We suppose that changes in the penial glands structure prevent their normal functioning. In the mollusks infested on reaching the sexual maturity, gradual reduction of distal part of reproductive system was observed, while in the mollusks infested before the sexual maturity, development of ancillary part of reproductive system was blocked. PMID:22384680

  15. The basal bodies of Chlamydomonas reinhardtii.

    PubMed

    Dutcher, Susan K; O'Toole, Eileen T

    2016-01-01

    The unicellular green alga, Chlamydomonas reinhardtii, is a biflagellated cell that can swim or glide. C. reinhardtii cells are amenable to genetic, biochemical, proteomic, and microscopic analysis of its basal bodies. The basal bodies contain triplet microtubules and a well-ordered transition zone. Both the mother and daughter basal bodies assemble flagella. Many of the proteins found in other basal body-containing organisms are present in the Chlamydomonas genome, and mutants in these genes affect the assembly of basal bodies. Electron microscopic analysis shows that basal body duplication is site-specific and this may be important for the proper duplication and spatial organization of these organelles. Chlamydomonas is an excellent model for the study of basal bodies as well as the transition zone. PMID:27252853

  16. Migraine attacks the Basal Ganglia

    PubMed Central

    2011-01-01

    Background With time, episodes of migraine headache afflict patients with increased frequency, longer duration and more intense pain. While episodic migraine may be defined as 1-14 attacks per month, there are no clear-cut phases defined, and those patients with low frequency may progress to high frequency episodic migraine and the latter may progress into chronic daily headache (> 15 attacks per month). The pathophysiology of this progression is completely unknown. Attempting to unravel this phenomenon, we used high field (human) brain imaging to compare functional responses, functional connectivity and brain morphology in patients whose migraine episodes did not progress (LF) to a matched (gender, age, age of onset and type of medication) group of patients whose migraine episodes progressed (HF). Results In comparison to LF patients, responses to pain in HF patients were significantly lower in the caudate, putamen and pallidum. Paradoxically, associated with these lower responses in HF patients, gray matter volume of the right and left caudate nuclei were significantly larger than in the LF patients. Functional connectivity analysis revealed additional differences between the two groups in regard to response to pain. Conclusions Supported by current understanding of basal ganglia role in pain processing, the findings suggest a significant role of the basal ganglia in the pathophysiology of the episodic migraine. PMID:21936901

  17. Middle pleistocene mollusks from St. Lawrence Island and their significance for the paleo-oceanography of the Bering Sea

    USGS Publications Warehouse

    Hopkins, D.M.; Rowland, R.W.; Patton, W.W., Jr.

    1972-01-01

    Drift, evidently of Illinoian age, was deposited on St. Lawrence Island at the margin of an ice cap that covered the highlands of the Chukotka Peninsula of Siberia and spread far eastward on the continental shelf of northern Bering Sea. Underlying the drift on the northwestward part of the island are mollusk-bearing beds deposited during the Kotzebuan Transgression. A comparison of mollusk faunas from St. Lawrence Island, Chukotka Peninsula, and Kotzebue Sound suggests that the present northward flow through Bering and Anadyr Straits was reversed during the Kotzebuan Transgression. Cold arctic water penetrated southward and southwestward bringing an arctic fauna to the Gulf of Anadyr. Warmer Pacific water probably entered eastern Bering Sea, passed eastward and northeastward around eastern and northern St. Lawrence Island, and then became entrained in the southward currents that passed through Anadyr Strait. ?? 1972.

  18. Prevalence and intensity of infection with third stage larvae of Angiostrongylus cantonensis in mollusks from Northeast Thailand.

    PubMed

    Tesana, Smarn; Srisawangwong, Tuanchai; Sithithaworn, Paiboon; Laha, Thewarach; Andrews, Ross

    2009-06-01

    Prevalences and intensity of infection with Angiostrongylus cantonensis third stage larvae were examined in mollusks to determine whether they are potential intermediate hosts in eight provinces, northeast Thailand. Mollusk samples were collected from 24 reservoirs (3 reservoirs/province) in close to human cases during the previous year. Six out of 24 localities and 9 (3 new record species) out of 27 species were found with the infection. The highest intensity in infected species was found to be only one or two snails, whereas the majority had very low or no infection. The highest density was found in Pila pesmei and the lowest in Pila polita. The edible snails, P. polita, P. pesmei, and Hemiplecta distincta have the potential to transmit A. cantonensis to man. The varying density levels of larvae in infected snails may reflect observed variation in symptoms of people who traditionally eat a raw snail dish. PMID:19478262

  19. The endemic mollusks reveal history of the long-lived Pliocene Lake Slavonia in NW Croatia

    NASA Astrophysics Data System (ADS)

    Mandic, Oleg; Kurečić, Tomislav; Neubauer, Thomas A.; Harzhauser, Mathias

    2015-04-01

    The present investigation deals with the fossil mollusk record of the long-lived Pliocene Lake Slavonia settled in the southern Pannonian Basin. The samples originate from Vukomeričke gorice, a low hill-range situated north of the Kupa River in the area between the towns of Zagreb, Sisak and Karlovac in NW Croatia. Representing the SW margin of the Lake Slavonia the freshwater deposits alternate there with the alluvial series, providing altogether about 400-m-thick, Pliocene continental succession, known in literature by informal name Paludina beds (acc. to a junior synonym of Viviparus). The endemic fauna of the Lake Slavonia became particularly well-known in the late 19th century after Melchior Neumayr demonstrated that the gradual evolutionary change of the mollusk phenotypes toward more complex morphology represents a function of adaptation to environmental change in the paleolake. Even Charles Darwin commented that result as by far the best case which I have ever met with, showing the direct influence of the conditions of life on the organization. The deposition in the Lake Slavonia (~4.5 to ~1.8 Ma) coincides with the Pliocene Climate Optimum (PCO), but captures also the transition into the Pleistocene climate marked by the initial Ice Age pulse at 2.59 Ma. The increase of polar temperatures resulted during PCO in a significant melting of the ice caps leading to a global sea level rise tentatively getting up to 25 m higher than today. Coincidence of the climate and geodynamic settings in southeastern Europe provided conditions supporting extended settlement of lacustrine environments including Lake Slavonia, Lake Kosovo, Lake Transylvania and Lake Dacia, all characterized by explosive adaptive radiations of viviparid snails. In particular, the latter adaptive radiations resulted in the regional phylostratigraphy of Lake Slavonia Viviparus species enabling excellent stratigraphic control for the investigated deposits. Hence, based on this evidence, the

  20. Specific features of the planarian Dugesia tigrina regeneration and mollusk Helix albescens nociception under weak electromagnetic shielding

    NASA Astrophysics Data System (ADS)

    Temur'yants, N. A.; Demtsun, N. A.; Kostyuk, A. S.; Yarmolyuk, N. S.

    2012-12-01

    It has been demonstrated that weak electromagnetic shielding stimulates regeneration in the planarian Dugesia tigrina, the stimulating intensity being dependent on both the initial state of the animals, which is determined by season, and their functional asymmetry. As has been shown, the effect of a weak electromagnetic field induces phasic changes in the nociceptive sensitivity of the mollusk Helix albescens: an increase in the sensitivity to a thermal stimulus is replaced by the development of the hypalgesic effect.

  1. Historical changes of sediments and mollusk assemblages in the Gulf of Batabanó (Caribbean Sea) in the twentieth century.

    PubMed

    Armenteros, Maickel; Díaz-Asencio, Misael; Fernández-Garcés, Raúl; Eriksson, Mats; Alonso-Hernández, Carlos; Sanchez-Cabeza, Joan-Albert

    2012-08-01

    The first paleoecological reconstruction of the biogeochemical conditions of the Gulf of Batabanó, Caribbean Sea was performed from (210)Pb-dated sediment cores. Depth profiles of 20 major elements and trace metals, organic compounds, grain size, and mollusk assemblage composition were determined from 9 stations encompassing unconsolidated sediments in the gulf. Spatial heterogeneity was evident for the geochemistry of sediments and for the mollusk assemblage composition. Our reconstruction indicates that pollution is not a critical threat to the ecosystem, although a slight historical increase of lead enrichment factor was detected probably due to long-range atmospheric fallout. Mollusk assemblages were composed by 168 species belonging to 59 families and no temporal trends in the species diversity or assemblage composition were detected, suggesting no depletion of diversity or habitat loss. Other signals of habitat loss such as changes in organic budget or increase of fine sediment fraction were absent or weak. Nitrogen retained in sediments changed by <1% in the century, indicating no historical events of eutrophication or oligotrophication in the gulf. Historical decrease of fine sediment fraction in the eastern sector would be linked to modifications in sedimentation rate, land use, and/or particle transport from the shelf border; this also suggests that both sectors have different sedimentary dynamics. Although, on theoretical grounds, historical fishery may have caused deleterious ecosystem effects by overexploitation of spiny lobster stocks, no evidence of habitat degradation or loss, caused by fisheries, could be detected. PMID:21881898

  2. A hyperpolarization-activated inward current alters swim frequency of the pteropod mollusk Clione limacina.

    PubMed

    Pirtle, Thomas J; Willingham, Kyle; Satterlie, Richard A

    2010-12-01

    The pteropod mollusk, Clione limacina, exhibits behaviorally relevant swim speed changes that occur within the context of the animal's ecology. Modulation of C. limacina swimming speed involves changes that occur at the network and cellular levels. Intracellular recordings from interneurons of the swim central pattern generator show the presence of a sag potential that is indicative of the hyperpolarization-activated inward current (I(h)). Here we provide evidence that I(h) in primary swim interneurons plays a role in C. limacina swimming speed control and may be a modulatory target. Recordings from central pattern generator swim interneurons show that hyperpolarizing current injection produces a sag potential that lasts for the duration of the hyperpolarization, a characteristic of cells possessing I(h). Following the hyperpolarizing current injection, swim interneurons also exhibit postinhibitory rebound (PIR). Serotonin enhances the sag potential of C. limacina swim interneurons while the I(h) blocker, ZD7288, reduces the sag potential. Furthermore, a negative correlation was found between the amplitude of the sag potential and latency to PIR. Because latency to PIR was previously shown to influence swimming speed, we hypothesize that I(h) has an effect on swimming speed. The I(h) blocker, ZD7288, suppresses swimming in C. limacina and inhibits serotonin-induced acceleration, evidence that supports our hypothesis. PMID:20696266

  3. The LBP/BPI multigenic family in invertebrates: Evolutionary history and evidences of specialization in mollusks.

    PubMed

    Baron, Olga Lucia; Deleury, Emeline; Reichhart, Jean-Marc; Coustau, Christine

    2016-04-01

    LBPs (lipopolysaccharide binding proteins) and BPIs (bactericidal permeability increasing proteins) are important proteins involved in defense against bacterial pathogens. We recently discovered a novel biocidal activity of a LBP/BPI from the gastropod Biomphalaria glabrata and demonstrated its role in parental immune protection of eggs, highlighting the importance of LBP/BPIs in invertebrate immunity. Here we characterize four additional LBP/BPI from B. glabrata, presenting conserved sequence architecture and exon-intron structure. Searches of invertebrate genomes revealed that existence of LBP/BPIs is not a conserved feature since they are absent from phyla such as arthropods and platyhelminths. Analyses of LBP/BPI transcripts from selected mollusk species showed recent parallel duplications in some species, including B. glabrata. In this snail species, LBP/BPI members vary in their expression tissue localization as well as their change in expression levels after immune challenges (Gram-negative bacterium; Gram-positive bacterium or yeast). These results, together with the predicted protein features provide evidences of functional specialization of LBP/BPI family members in molluscs. PMID:26608112

  4. Responses to magnetic stimuli recorded in peripheral nerves in the marine nudibranch mollusk Tritonia diomedea.

    PubMed

    Pavlova, Galina A; Glantz, Raymon M; Dennis Willows, A O

    2011-10-01

    Prior behavioral and neurophysiological studies provide evidence that the nudibranch mollusk Tritonia orients to the earth's magnetic field. Earlier studies of electrophysiological responses in certain neurons of the brain to changing ambient magnetic fields suggest that although certain identified brain cells fire impulses when the ambient field is changed, these neuron somata and their central dentritic and axonal processes are themselves not primary magnetic receptors. Here, using semi-intact animal preparations from which the brain was removed, we recorded from peripheral nerve trunks. Using techniques to count spikes in individual nerves and separately also to identify, then count individual axonal spikes in extracellular records, we found both excitatory and inhibitory axonal responses elicited by changes in the direction of ambient earth strength magnetic fields. We found responses in nerves from many locations throughout the body and in axons innervating the body wall and rhinophores. Our results indicate that primary receptors for geomagnetism in Tritonia are not focally concentrated in any particular organ, but appear to be widely dispersed in the peripheral body tissues. PMID:21717186

  5. Interspecific variation of metal concentrations in three bivalve mollusks from Galicia.

    PubMed

    Saavedra, Y; González, A; Fernández, P; Blanco, J

    2004-10-01

    There has been growing concern about the inflow of metals to the coastal areas because they can be toxic to aquatic and human life. Some studies have demonstrated the existence of species-specific differences in the metal concentrations of mollusks. We compared metal concentrations between Mytilus galloprovincialis, used as a water quality indicator, and two other bivalve species collected for human consumption (Venerupis pullastra and Cerastoderma edule) in different locations on the Galician coast (northwest Spain). M. galloprovincialis was found to be the best zinc and lead accumulator, whereas silver and arsenic were preferentially accumulated by V. pullastra and chromium and nickel by C. edule. Bivalve concentrations of mercury, cadmium, chromium, arsenic, silver, and zinc appeared to be linearly related to environmental concentrations, but this was not the case with copper, nickel, and lead in some species, which indicated that there is a nonlinear accumulation of these metals or an influence of the environmental conditions on species accumulation. The relationship between metal concentration in mussels and in the two other species varied with the metal and the species. In some cases the correlation was high, making it possible to use mussels as bioindicators for the other species. In other cases the correlation was moderate or low, therefore rendering mussels of little or no use in predicting the metal concentrations in the two other species. PMID:15386128

  6. Calcium concretions: Evidence of contaminant exposure in three species of marine mollusks

    SciTech Connect

    Benyi, S.J.

    1994-12-31

    Researchers have hypothesized that calcium concretions identified in the kidney of quahogs collected along an urban pollution gradient may result from the sequestering of water- and sediment-borne contaminants. The objectives of this study were to determine if renal calcium deposition was a response to contaminants and to assess calcium concretions as a marker of exposure. Renal calcium concretions in three species of marine mollusks (northern quahog (Mercenaria mercenaria), eastern oyster (Crassostrea virginica) and softshell (Mya arenaria)) were quantified after a 28-day laboratory exposure to a reference or contaminated sediment (Black Rock Harbor, BRH). Hemolymph calcium, the source of calcium for concretions, was measured weekly to detect a calcium concentration change when and if calcium concretions were deposited in the kidney. Results indicated no effect of contaminated sediment on the hemolymph calcium of any species tested. The response to the contaminants, manifested as renal calcium concretions, was species-specific. Renal concretions were not found in the oysters. However, renal calcium concretions increased from 3.7% of reference-exposed to 52.4% of BRH-exposed softshells. While renal calcium concretions were found in the majority of quahogs, there were more renal concretions in BRH-exposed quahogs than the reference exposed quahogs and the concretions were larger. The increase in renal calcium concretions in quahogs and softshells exposed to contaminants in sediment indicates that renal calcium concretion formation may be associated with contaminant exposure in these species.

  7. Mollusk collecting and environmental change during the Prehistoric Period in the Mariana Islands

    NASA Astrophysics Data System (ADS)

    Amesbury, J. R.

    2007-12-01

    Archaeological research in the Mariana Islands has revealed changes in mollusk collecting during the Prehistoric Period (approximately 1500 BC to AD 1521). The earliest people at Tumon Bay, Guam and Chalan Piao, Saipan collected mostly bivalves, especially the arc clam Anadara antiquata. After several hundred years, they no longer collected A. antiquata, but collected smaller bivalves instead. By AD 1000, they collected mostly gastropods, primarily the coral reef species Strombus gibberulus gibbosus. One possible explanation is that the people preferred the large arc clam but overharvested it until they were forced to eat the smaller bivalves and then the snails. However, recent evidence in the form of mangrove wood and mangrove pollen supports another explanation, one of non-anthropogenic environmental change. In this case, the relative sea-level decline, which took place in the Marianas within the last 4,000 years, caused the demise of mangrove habitats and of the arc clam at Tumon Bay, Guam and Chalan Piao, Saipan. As mangrove habitats were diminished by sea-level decline, collecting effort shifted to coral reefs, and S. gibberulus gibbosus was harvested throughout the remainder of the Prehistoric Period and into the Historic Period. Southern Guam is the only area in the Marianas in which A. antiquata increased in abundance during the Prehistoric Period. The same types of evidence, mangrove wood and mangrove pollen, indicate that, in contrast to the situation at Tumon Bay and Chalan Piao, mangroves increased in abundance in southern Guam.

  8. Irradiated bivalve mollusks: Use of EPR spectroscopy for identification and dosimetry

    NASA Astrophysics Data System (ADS)

    Alberti, Angelo; Chiaravalle, Eugenio; Fuochi, Piergiorgio; Macciantelli, Dante; Mangiacotti, Michele; Marchesani, Giuliana; Plescia, Elena

    2011-12-01

    High energy radiation treatment of foodstuff for microbial control and shelf-life extension is being used in many countries. However, for consumer protection and information, the European Union has adopted the Directives 1999/2/EC and 1999/3/EC to harmonize the rules concerning the treatment and trade of irradiated foods in EU countries. Among the validated methods to detect irradiated foods the EU directives also include Electron Paramagnetic Resonance (EPR/ESR) spectroscopy.We describe herein the use of EPR for identification of four species of bivalve mollusks, i.e. brown Venus shells (Callista chione), clams (Tapes semidecussatus), mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis) irradiated with 60Co γ-rays. EPR could definitely identify irradiated seashells due to the presence of long-lived free radicals, primarily CO2-, CO33-, SO2- and SO3- radical anions. The presence of other organic free radicals, believed to originate from conchiolin, a scleroprotein present in the shells, was also ascertained. The use of one of these radicals as a marker for irradiation of brown Venus shells and clams can be envisaged. We also propose a dosimetric protocol for the reconstruction of the administered dose in irradiated oysters.

  9. Stress detection in bivalve mollusk using non-invasive bioelectric monitoring of myoneural behavior

    SciTech Connect

    Morgan, E.L.; Hardison, B.S.; Dawson, V.K.; Waller, D.; Waller, W.T.; Dickson, K.L.; Allen, H.J.

    1995-12-31

    Few studies have demonstrated cause-and-effect linkages between extrinsic environmental factors and intrinsic bioelectric action potentials of bivalve mollusk using non-invasive, non-destructive approaches. A non-invasive, external probe configuration and detection system, similar to one used previously with native unionids, was developed for continuously monitoring bioelectric activities of clams and mussels. Using remote probes and differential amplifiers, bioelectric activities were recorded for cardiac, adductor, siphon and foot responses using a computer equipped with integrating software. To test if remote, non-invasive probes would detect similar information to that recorded by invasive needle electrodes, two individuals of zebra mussel (Dreissenia polymorpha), and Asiatic clam (Corbicula fluminea) were each configured with two sets of probes. One set was inserted between the valves and along the inside surface of the shelf; the other set was positioned remotely about the outside margins of the valves. Signal validation was made by simultaneously recording bioelectric responses for the same animal from both sets of probes. In preliminary stress tests monitored bivalves were subjected to changes in temperatures over 2 to 3 hr intervals from ambient to potentially lethal levels (20 to 30 C for zebra, 25 C to 40 C for corbicula). Dramatic increases resulted in both number and amplitude of cardiac events as temperature increased. Planned studies will use this approach to evaluate bivalve myoneural behavior patterns in response to chemical and non-chemical stimuli.

  10. Functional Neuroanatomy of the Basal Ganglia

    PubMed Central

    Lanciego, José L.; Luquin, Natasha; Obeso, José A.

    2012-01-01

    The “basal ganglia” refers to a group of subcortical nuclei responsible primarily for motor control, as well as other roles such as motor learning, executive functions and behaviors, and emotions. Proposed more than two decades ago, the classical basal ganglia model shows how information flows through the basal ganglia back to the cortex through two pathways with opposing effects for the proper execution of movement. Although much of the model has remained, the model has been modified and amplified with the emergence of new data. Furthermore, parallel circuits subserve the other functions of the basal ganglia engaging associative and limbic territories. Disruption of the basal ganglia network forms the basis for several movement disorders. This article provides a comprehensive account of basal ganglia functional anatomy and chemistry and the major pathophysiological changes underlying disorders of movement. We try to answer three key questions related to the basal ganglia, as follows: What are the basal ganglia? What are they made of? How do they work? Some insight on the canonical basal ganglia model is provided, together with a selection of paradoxes and some views over the horizon in the field. PMID:23071379

  11. Striatal plasticity and basal ganglia circuit function.

    PubMed

    Kreitzer, Anatol C; Malenka, Robert C

    2008-11-26

    The dorsal striatum, which consists of the caudate and putamen, is the gateway to the basal ganglia. It receives convergent excitatory afferents from cortex and thalamus and forms the origin of the direct and indirect pathways, which are distinct basal ganglia circuits involved in motor control. It is also a major site of activity-dependent synaptic plasticity. Striatal plasticity alters the transfer of information throughout basal ganglia circuits and may represent a key neural substrate for adaptive motor control and procedural memory. Here, we review current understanding of synaptic plasticity in the striatum and its role in the physiology and pathophysiology of basal ganglia function. PMID:19038213

  12. sine oculis in basal Metazoa.

    PubMed

    Bebenek, Ilona G; Gates, Ruth D; Morris, Joshua; Hartenstein, Volker; Jacobs, David K

    2004-07-01

    We report the recovery of homologs of Six1/2/sine oculis (so), a homeodomain-containing member of the Six-gene family, from a diverse set of basal Metazoa, including representatives of the poriferan classes Demospongia, Calcarea and Hexactinellida, the cnidarian classes Hydrozoa, Scyphozoa and Anthozoa, as well as a ctenophore. so sequences were also recovered from a platyhelminth, an echiurid and two bivalve molluscs, members of the super-phyletic group Lophotrochozoa. In the case of the platyhelminth, multiple distinct so sequences were recovered, as well as a member of the related group Six4/5/D-Six4. Extended sequences of the so gene were recovered from the demosponge, Haliclona sp., and the scyphozoan Aurelia aurita via PCR, and 3' RACE. The affinities of all recovered sequences were assessed using a parsimony analysis based on both nucleic and amino acid sequence and using successive character weighting. Our results indicate that so is highly conserved across the animal kingdom. Preliminary expression data for Aurelia reveal that transcripts of the so homolog are present in the manubrium as well as in the rhopalia, which contain the statocyst and eyes, in the free-swimming ephyra and juvenile stages of these jellyfish. PMID:15221378

  13. The basal ganglia communicate with the cerebellum.

    PubMed

    Bostan, Andreea C; Dum, Richard P; Strick, Peter L

    2010-05-01

    The basal ganglia and cerebellum are major subcortical structures that influence not only movement, but putatively also cognition and affect. Both structures receive input from and send output to the cerebral cortex. Thus, the basal ganglia and cerebellum form multisynaptic loops with the cerebral cortex. Basal ganglia and cerebellar loops have been assumed to be anatomically separate and to perform distinct functional operations. We investigated whether there is any direct route for basal ganglia output to influence cerebellar function that is independent of the cerebral cortex. We injected rabies virus (RV) into selected regions of the cerebellar cortex in cebus monkeys and used retrograde transneuronal transport of the virus to determine the origin of multisynaptic inputs to the injection sites. We found that the subthalamic nucleus of the basal ganglia has a substantial disynaptic projection to the cerebellar cortex. This pathway provides a means for both normal and abnormal signals from the basal ganglia to influence cerebellar function. We previously showed that the dentate nucleus of the cerebellum has a disynaptic projection to an input stage of basal ganglia processing, the striatum. Taken together these results provide the anatomical substrate for substantial two-way communication between the basal ganglia and cerebellum. Thus, the two subcortical structures may be linked together to form an integrated functional network. PMID:20404184

  14. Readiness in the Basal Reader: An Update.

    ERIC Educational Resources Information Center

    Perkins, Pamela

    A study examined two 1989 basal reading series' (published by McGraw Hill and Holt) readiness/priming sequences in order to ascertain the theoretical bases of each and then compared the findings with those of an earlier study. All pages of the readiness/priming sequence student texts and workbooks of both basal reading series were analyzed using…

  15. Modern basal insulin analogs: An incomplete story.

    PubMed

    Singh, Awadhesh Kumar; Gangopadhyay, Kalyan Kumar

    2014-11-01

    The currently available basal insulin does not completely mimic the endogenous insulin secretion. This has continued to promote the search for ideal basal insulin. The newer basal insulin have primarily focused on increasing the duration of action, reducing variability, and reducing the incidence of hypoglycemia, particularly nocturnal. However, the changing criteria of hypoglycemia within a short span of a few years along with the surprising introduction of major cardiac events as another outcome measure has not only clouded the assessment of basal insulin but has also polarized opinion worldwide about the utility of the newer basal insulin. A critical review of both the pre and post FDA analysis of all the basal insulin in this article attempts to clear some of the confusion surrounding the issues of hypoglycemia and glycemic control. This article also discusses all the trials and meta-analysis done on all the current basal insulin available along with their head-to-head comparison with particular attention to glycemic control and hypoglycemic events including severe and nocturnal hypoglycemia. This in-depth analysis hopes to provide a clear interpretation of the various analyses available in literature at this point of time thereby acting as an excellent guide to the readers in choosing the most appropriate basal insulin for their patient. PMID:25364672

  16. Modern basal insulin analogs: An incomplete story

    PubMed Central

    Singh, Awadhesh Kumar; Gangopadhyay, Kalyan Kumar

    2014-01-01

    The currently available basal insulin does not completely mimic the endogenous insulin secretion. This has continued to promote the search for ideal basal insulin. The newer basal insulin have primarily focused on increasing the duration of action, reducing variability, and reducing the incidence of hypoglycemia, particularly nocturnal. However, the changing criteria of hypoglycemia within a short span of a few years along with the surprising introduction of major cardiac events as another outcome measure has not only clouded the assessment of basal insulin but has also polarized opinion worldwide about the utility of the newer basal insulin. A critical review of both the pre and post FDA analysis of all the basal insulin in this article attempts to clear some of the confusion surrounding the issues of hypoglycemia and glycemic control. This article also discusses all the trials and meta-analysis done on all the current basal insulin available along with their head-to-head comparison with particular attention to glycemic control and hypoglycemic events including severe and nocturnal hypoglycemia. This in-depth analysis hopes to provide a clear interpretation of the various analyses available in literature at this point of time thereby acting as an excellent guide to the readers in choosing the most appropriate basal insulin for their patient. PMID:25364672

  17. Toughening mechanisms in laminated composites: A biomimetic study in mollusk shells

    NASA Astrophysics Data System (ADS)

    Kamat, Shekhar Shripad

    2000-10-01

    Mollusk shells can be described as structural biocomposite materials composed of a mineral (aragonite) and a continuous, albeit minor, organic (protein) component. The conch shell, Strombus Gigas, has intermediate strength and high fracture toughness. The high fracture toughness is a result of enhanced energy dissipation during crack propagation due to delamination, crack bridging, frictional sliding etc. A theoretical and experimental study was conducted on the crack bridging mechanisms operative in the shell. Four-point bend tests were conducted. Acoustic emission and post-mortem dye penetrants were used to characterize the crack propagation, together with conventional fractography. A two layer composite configuration is seen in the shells, with the tough and weak layers having a toughness ratio of ˜4 (Ktough = 2.2MPam1/2). This toughness ratio is a requisite for multiple cracking in the weak layer. A theoretical shear lag analysis of the crack bridging phenomena in the tough layer is shown to lead to a bridging law for the crack wake of the form of p = betau1/2 (p is the bridging traction for a crack opening u, with beta, being a constant of proportionality). Finite element analysis yielded a value of beta = 630 Nmm-5/2 and ucritical = 5 mum for the bridging law parameters. In a nonlinear fracture mechanics phenomenology, these values are relevant material parameters, rather than a critical stress intensity factor. The work of fracture for unnotched specimens is three orders of magnitude higher than mineral aragonite, and is demonstrated numerically incorporating the toughening mechanisms in the shell. Similar structural adaptations have been observed and studied in the red abalone shell, haliotis rufescens and the spines of the sea urchin, Heterocentrotus trigonarius. The toughening mechanisms seen in these shells give insight into structural design needs of brittle matrix composites (BMC) as well as conventional structural ceramics.

  18. Jackknife-corrected parametric bootstrap estimates of growth rates in bivalve mollusks using nearest living relatives.

    PubMed

    Dexter, Troy A; Kowalewski, Michał

    2013-12-01

    Quantitative estimates of growth rates can augment ecological and paleontological applications of body-size data. However, in contrast to body-size estimates, assessing growth rates is often time-consuming, expensive, or unattainable. Here we use an indirect approach, a jackknife-corrected parametric bootstrap, for efficient approximation of growth rates using nearest living relatives with known age-size relationships. The estimate is developed by (1) collecting a sample of published growth rates of closely related species, (2) calculating the average growth curve using those published age-size relationships, (3) resampling iteratively these empirically known growth curves to estimate the standard errors and confidence bands around the average growth curve, and (4) applying the resulting estimate of uncertainty to bracket age-size relationships of the species of interest. This approach was applied to three monophyletic families (Donacidae, Mactridae, and Semelidae) of mollusk bivalves, a group characterized by indeterministic shell growth, but widely used in ecological, paleontological, and geochemical research. The resulting indirect estimates were tested against two previously published geochemical studies and, in both cases, yielded highly congruent age estimates. In addition, a case study in applied fisheries was used to illustrate the potential of the proposed approach for augmenting aquaculture management practices. The resulting estimates of growth rates place body size data in a constrained temporal context and confidence intervals associated with resampling estimates allow for assessing the statistical uncertainty around derived temporal ranges. The indirect approach should allow for improved evaluation of diverse research questions, from sustainability of industrial shellfish harvesting to climatic interpretations of stable isotope proxies extracted from fossil skeletons. PMID:24071629

  19. Nevoid Basal Cell Carcinoma Syndrome (Gorlin Syndrome).

    PubMed

    Bresler, Scott C; Padwa, Bonnie L; Granter, Scott R

    2016-06-01

    Nevoid basal cell carcinoma syndrome, or basal cell nevus syndrome (Gorlin syndrome), is a rare autosomal dominantly inherited disorder that is characterized by development of basal cell carcinomas from a young age. Other distinguishing clinical features are seen in a majority of patients, and include keratocystic odontogenic tumors (formerly odontogenic keratocysts) as well as dyskeratotic palmar and plantar pitting. A range of skeletal and other developmental abnormalities are also often seen. The disorder is caused by defects in hedgehog signaling which result in constitutive pathway activity and tumor cell proliferation. As sporadic basal cell carcinomas also commonly harbor hedgehog pathway aberrations, therapeutic agents targeting key signaling constituents have been developed and tested against advanced sporadically occurring tumors or syndromic disease, leading in 2013 to FDA approval of the first hedgehog pathway-targeted small molecule, vismodegib. The elucidation of the molecular pathogenesis of nevoid basal cell carcinoma syndrome has resulted in further understanding of the most common human malignancy. PMID:26971503

  20. Structural, functional, and evolutionary aspects of galectins in aquatic mollusks: From a sweet tooth to the Trojan horse

    PubMed Central

    Vasta, GR; Feng, C; Bianchet, MA; Bachvaroff, TR; Tasumi, S

    2015-01-01

    Galectins constitute a conserved and widely distributed lectin family characterized by their binding affinity for β-galactosides and a unique binding site sequence motif in the carbohydrate recognition domain (CRD). In spite of their structural conservation, galectins display a remarkable functional diversity, by participating in developmental processes, cell adhesion and motility, regulation of immune homeostasis, and recognition of glycans on the surface of viruses, bacteria and protozoan parasites. In contrast with mammals, and other vertebrate and invertebrate taxa, the identification and characterization of bona fide galectins in aquatic mollusks has been relatively recent. Most of the studies have focused on the identification and domain organization of galectin-like transcripts or proteins in diverse tissues and cell types, including hemocytes, and their expression upon environmental or infectious challenge. Lectins from the eastern oyster Crassostrea virginica, however, have been characterized in their molecular, structural and functional aspects and some notable features have become apparent in the galectin repertoire of aquatic mollusks. These including less diversified galectin repertoires and different domain organizations relative to those observed in vertebrates, carbohydrate specificity for blood group oligosaccharides, and up regulation of galectin expression by infectious challenge, a feature that supports their proposed role(s) in innate immune responses. Although galectins from some aquatic mollusks have been shown to recognize microbial pathogens and parasites and promote their phagocytosis, they can also selectively bind to phytoplankton components, suggesting that they also participate in uptake and intracellular digestion of microalgae. In addition, the experimental evidence suggests that the protozoan parasite Perkinsus marinus has co-evolved with the oyster host to be selectively recognized by the oyster hemocyte galectins over algal food

  1. Structural, functional, and evolutionary aspects of galectins in aquatic mollusks: From a sweet tooth to the Trojan horse.

    PubMed

    Vasta, G R; Feng, C; Bianchet, M A; Bachvaroff, T R; Tasumi, S

    2015-09-01

    Galectins constitute a conserved and widely distributed lectin family characterized by their binding affinity for β-galactosides and a unique binding site sequence motif in the carbohydrate recognition domain (CRD). In spite of their structural conservation, galectins display a remarkable functional diversity, by participating in developmental processes, cell adhesion and motility, regulation of immune homeostasis, and recognition of glycans on the surface of viruses, bacteria and protozoan parasites. In contrast with mammals, and other vertebrate and invertebrate taxa, the identification and characterization of bona fide galectins in aquatic mollusks has been relatively recent. Most of the studies have focused on the identification and domain organization of galectin-like transcripts or proteins in diverse tissues and cell types, including hemocytes, and their expression upon environmental or infectious challenge. Lectins from the eastern oyster Crassostrea virginica, however, have been characterized in their molecular, structural and functional aspects and some notable features have become apparent in the galectin repertoire of aquatic mollusks. These including less diversified galectin repertoires and different domain organizations relative to those observed in vertebrates, carbohydrate specificity for blood group oligosaccharides, and up regulation of galectin expression by infectious challenge, a feature that supports their proposed role(s) in innate immune responses. Although galectins from some aquatic mollusks have been shown to recognize microbial pathogens and parasites and promote their phagocytosis, they can also selectively bind to phytoplankton components, suggesting that they also participate in uptake and intracellular digestion of microalgae. In addition, the experimental evidence suggests that the protozoan parasite Perkinsus marinus has co-evolved with the oyster host to be selectively recognized by the oyster hemocyte galectins over algal food

  2. Heavy metal levels in marine mollusks from areas with, or without, mining activities along the Gulf of California, Mexico.

    PubMed

    Cadena-Cárdenas, Lázaro; Méndez-Rodríguez, Lía; Zenteno-Savín, Tania; García-Hernández, Jaqueline; Acosta-Vargas, Baudilio

    2009-07-01

    To assess the safety for human consumption of commercially important bivalves harvested from areas with or without mining activities, we compared the levels of heavy metals in mollusks collected from different coastal environments along the Gulf of California. We sampled the mussel Mytilus edulis and the clams Laevicardium elatum and Megapitaria squalida (June 2004) and the clam Chione californiensis (November 2006). Concentrations of cadmium, lead, nickel, zinc, iron, copper, and manganese in the soft tissue of the mollusks were measured by atomic absorption spectrophotometry. Based on dry weight, the highest average concentrations of iron, copper, and cadmium were found in clams from Loreto (572, 181, and 4.66 mg/kg, respectively); that of nickel, in mussels from San Luquitas (12.2 mg/kg); that of zinc, both in mussels from San Luquitas and in clams from Golfo de Santa Clara (94.3 and 91.8 mg/kg, respectively); and those of lead and manganese in clams from the Golfo de Santa Clara (9.2 and 3.68 mg/kg, respectively). Although mollusks were taken from coastal areas of the Gulf of California, which are considered to be contaminated by mining activities, the heavy metals in the sediments apparently were in a chemical form that had low bioavailability for the bivalves feeding in those areas. The interplay of oceanographic conditions and the chemical composition of anthropogenic inputs into the environment is not well understood. Thus, these factors or their interaction could potentially result in increased concentration and bioavailability of such metals in areas without effluent generated by mining activities. PMID:18825444

  3. Metastatic Basal Cell Carcinoma Accompanying Gorlin Syndrome

    PubMed Central

    Bilir, Yeliz; Gokce, Erkan; Ozturk, Banu; Deresoy, Faik Alev; Yuksekkaya, Ruken; Yaman, Emel

    2014-01-01

    Gorlin-Goltz syndrome or basal cell nevus syndrome is an autosomal dominant syndrome characterized by skeletal anomalies, numerous cysts observed in the jaw, and multiple basal cell carcinoma of the skin, which may be accompanied by falx cerebri calcification. Basal cell carcinoma is the most commonly skin tumor with slow clinical course and low metastatic potential. Its concomitance with Gorlin syndrome, resulting from a mutation in a tumor suppressor gene, may substantially change morbidity and mortality. A 66-year-old male patient with a history of recurrent basal cell carcinoma was presented with exophthalmus in the left eye and the lesions localized in the left lateral orbita and left zygomatic area. His physical examination revealed hearing loss, gapped teeth, highly arched palate, and frontal prominence. Left orbital mass, cystic masses at frontal and ethmoidal sinuses, and multiple pulmonary nodules were detected at CT scans. Basal cell carcinoma was diagnosed from biopsy of ethmoid sinus. Based on the clinical and typical radiological characteristics (falx cerebri calcification, bifid costa, and odontogenic cysts), the patient was diagnosed with metastatic skin basal cell carcinoma accompanied by Gorlin syndrome. Our case is a basal cell carcinoma with aggressive course accompanying a rarely seen syndrome. PMID:25506011

  4. The Basal Ganglia-Circa 1982

    NASA Technical Reports Server (NTRS)

    Mehler, William R.

    1981-01-01

    Our review has shown that recent studies with the new anterograde and retrograde axon transport methods have confirmed and extended our knowledge of the projection of the basal ganglia and clarified their sites of origin. They have thrown new light on certain topographic connectional relationships and revealed several new reciprocal connections between constituent nuclei of the basal ganglia. Similarly, attention has been drawn to the fact that there have also been many new histochemical techniques introduced in recent years that are now providing regional biochemical overlays for connectional maps of the central nervous system, especially regions in, or interconnecting with, the basal ganglia. However, although these new morphological biochemical maps are very complex and technically highly advanced, our understanding of the function controlled by the basal ganglia still remains primitive. The reader who is interested in some new ideas of the functional aspects of the basal ganglia is directed to Nauta's proposed conceptual reorganization of the basal ganglia telencephalon and to Marsden's more clinically orientated appraisal of the unsolved mysteries of the basal ganglia participation in the control of movement.

  5. Basal encephalocele and morning glory syndrome.

    PubMed Central

    Caprioli, J; Lesser, R L

    1983-01-01

    Basal encephaloceles are often associated with other midline anomalies such as hypertelorism, broad nasal root, cleft lip, and cleft palate. Optic disc anomalies such as pallor, dysplasia, optic pit, coLoboma, and megalopapilla have been reported to occur in patients with basal encephalocele We report a case of a child with a sphenoethmoidal encephalocele and morning glory syndrome of the optic nerve. The presence of such optic nerve anomalies with facial midline anomalies should alert the clinician to the possible presence of a basal encephalocele. Images PMID:6849854

  6. Thermodynamic significance of human basal metabolism

    NASA Astrophysics Data System (ADS)

    Wang, Cuncheng

    1993-06-01

    The human basal state, a non-equilibrium steady state, is analysed in this paper in the light of the First and Second Laws of Thermodynamics whereby the thermodynamic significance of the basal metabolic rate and its distinction to the dissipation function and exergy loss are identified. The analysis demonstrates the correct expression of the effects of the blood flow on the heat balance in a human-body bio-heat model and the relationship between the basal metabolic rate and the blood perfusion.

  7. Exploring errors in paleoclimate proxy reconstructions using Monte Carlo simulations: paleotemperature from mollusk and coral geochemistry

    NASA Astrophysics Data System (ADS)

    Carré, M.; Sachs, J. P.; Wallace, J. M.; Favier, C.

    2012-03-01

    Quantitative reconstructions of the past climate statistics from geochemical coral or mollusk records require quantified error bars in order to properly interpret the amplitude of the climate change and to perform meaningful comparisons with climate model outputs. We introduce here a more precise categorization of reconstruction errors, differentiating the error bar due to the proxy calibration uncertainty from the standard error due to sampling and variability in the proxy formation process. Then, we propose a numerical approach based on Monte Carlo simulations with surrogate proxy-derived climate records. These are produced by perturbing a known time series in a way that mimics the uncertainty sources in the proxy climate reconstruction. A freely available algorithm, MoCo, was designed to be parameterized by the user and to calculate realistic systematic and standard errors of the mean and the variance of the annual temperature, and of the mean and the variance of the temperature seasonality reconstructed from marine accretionary archive geochemistry. In this study, the algorithm is used for sensitivity experiments in a case study to characterize and quantitatively evaluate the sensitivity of systematic and standard errors to sampling size, stochastic uncertainty sources, archive-specific biological limitations, and climate non-stationarity. The results of the experiments yield an illustrative example of the range of variations of the standard error and the systematic error in the reconstruction of climate statistics in the Eastern Tropical Pacific. Thus, we show that the sample size and the climate variability are the main sources of the standard error. The experiments allowed the identification and estimation of systematic bias that would not otherwise be detected because of limited modern datasets. Our study demonstrates that numerical simulations based on Monte Carlo analyses are a simple and powerful approach to improve the understanding of the proxy records

  8. Residues and chiral signatures of organochlorine pesticides in mollusks from the coastal regions of the Yangtze River Delta: source and health risk implication.

    PubMed

    Zhou, Shanshan; Tang, Qiaozhi; Jin, Meiqing; Liu, Weiping; Niu, Lili; Ye, Hui

    2014-11-01

    The residues and enantiomeric fractions of organochlorine pesticides (OCPs) were measured in 11 mollusk species collected from the coastal areas along the Yangtze River Delta to evaluate the status, potential sources, and health risks of pollution in these areas. The concentrations of DDTs, HCHs, and chlordanes ranged from 6.22 to 398.19, 0.66-7.11, and 0.14-4.08 ng g(-1) based on wet weight, respectively; DDTs and HCHs have the highest values, globally. The DDTs increased and the HCHs decreased compared to historical data. Both the box-and-whisker plots and the one-way ANOVA tests indicated that the OCP levels varied little between sampling locations and organism species. The compositions of the DDTs and HCHs suggested a cocktail input pattern of fresh and weathered technical products. The comparative EF values for the α-HCH between the sediments and mollusks, as well as the lack of any discernible difference in the relative proportions of HCH isomers among different species from the same sampling site implied that the HCH residues in the mollusks came directly from the surrounding environment. However, the biotransformation of DDTs in mollusks cannot be precluded. The assessments performed based on several available guidelines suggested that although no significant human health risks were associated with the dietary intake of OCPs, the concentrations of DDTs exceeded the maximum residual limits of China and many developed nations. Moreover, an increased lifetime cancer risk from dietary exposure to either DDTs or HCHs remains a possibility. Because non-racemic OCP residues are common in the mollusk samples, our results suggest a need to further explore the levels and toxicity of the chiral contaminants in mollusks and other foodstuff to develop the human risk assessment framework based on chiral signatures. PMID:25113182

  9. Plant basal resistance to nematodes: an update.

    PubMed

    Holbein, Julia; Grundler, Florian M W; Siddique, Shahid

    2016-03-01

    Most plant-parasitic nematodes are obligate biotrophs feeding on the roots of their hosts. Whereas ectoparasites remain on the root surface and feed on the outer cell layers, endoparasitic nematodes enter the host to parasitize cells around or within the central cylinder. Nematode invasion and feeding causes tissue damage which may, in turn, lead to the activation of host basal defence responses. Hitherto, research interests in plant-nematode interaction have emphasized effector-triggered immunity rather than basal plant defence responses. However, some recent investigations suggest that basal defence pathways are not only activated but also play an important role in determining interaction outcomes. In this review we discuss the major findings and point out future directions to dissect the molecular mechanisms underlying plant basal defence to nematodes further. PMID:26842982

  10. Multiple Beneficial Lipids Including Lecithin Detected in the Edible Invasive Mollusk Crepidula fornicata from the French Northeastern Atlantic Coast

    PubMed Central

    Dagorn, Flore; Buzin, Florence; Couzinet-Mossion, Aurélie; Decottignies, Priscilla; Viau, Michèle; Rabesaotra, Vony; Barnathan, Gilles; Wielgosz-Collin, Gaëtane

    2014-01-01

    The invasive mollusk Crepidula fornicata, occurring in large amounts in bays along the French Northeastern Atlantic coasts, may have huge environmental effects in highly productive ecosystems where shellfish are exploited. The present study aims at determining the potential economic value of this marine species in terms of exploitable substances with high added value. Lipid content and phospholipid (PL) composition of this mollusk collected on the Bourgneuf Bay were studied through four seasons. Winter specimens contained the highest lipid levels (5.3% dry weight), including 69% of PLs. Phosphatidylcholine (PC) was the major PL class all year, accounting for 63.9% to 88.9% of total PLs. Consequently, the winter specimens were then investigated for PL fatty acids (FAs), and free sterols. Dimethylacetals (DMAs) were present (10.7% of PL FA + DMA mixture) revealing the occurrence of plasmalogens. More than forty FAs were identified, including 20:5n-3 (9.4%) and 22:6n-3 (7.3%) acids. Fourteen free sterols were present, including cholesterol at 31.3% of the sterol mixture and about 40% of phytosterols. These data on lipids of C. fornicata demonstrate their positive attributes for human nutrition and health. The PL mixture, rich in PC and polyunsaturated FAs, offers an interesting alternative source of high value-added marine lecithin. PMID:25532566

  11. A high-elevation MIS 5 hydrologic record using mollusks and ostracodes from Snowmass Village, Colorado, USA

    NASA Astrophysics Data System (ADS)

    Sharpe, Saxon E.; Bright, Jordon

    2014-11-01

    Sediments containing terrestrial and aquatic mollusks and ostracodes from the Ziegler Reservoir fossil site (2705 m elevation) near Snowmass Village, Colorado, span ~ 130-87 ka (MIS 5e through 5b). The southeastern area of the site where taxa were recovered was a relatively fresh, shallow, well-vegetated wetland during MIS 5e through 5c time, approximately 2 m deep, with a total dissolved solids value of ~ 200-1000 mg L- 1. The wetland was seasonally or annually variable and groundwater discharged along the margins of the bounding moraine. Groundwater likely contributed solutes to the system and may have contributed 18O-enriched water. Based on stable isotopes from ostracode calcite (δ18OOST and δ13COST), seasonal evaporation occurred and the dissolved inorganic carbon pool was unexpectedly enriched in 13C. The mollusk and ostracode faunas changed little across the MIS 5e/5d/5c boundaries, whereas a distinct change in the ostracode fauna occurred between the deposition of Unit 11 and Unit 13, which corresponds in time to the MIS 5c/5b boundary, indicating some combination of increased surface and/or groundwater flow, a decrease in water temperature, and a freshening and a possible deepening of the wetland.

  12. Characterization of Three Tetrabromobisphenol-S Derivatives in Mollusks from Chinese Bohai Sea: A Strategy for Novel Brominated Contaminants Identification

    NASA Astrophysics Data System (ADS)

    Liu, Ai-Feng; Tian, Yong; Yin, Nuo-Ya; Yu, Miao; Qu, Guang-Bo; Shi, Jian-Bo; Du, Yu-Guo; Jiang, Gui-Bin

    2015-07-01

    Identification of novel brominated contaminants in the environment, especially the derivatives and byproducts of brominated flame retardants (BFRs), has become a wide concern because of their adverse effects on human health. Herein, we qualitatively and quantitatively identified three byproducts of tetrabromobisphenol-S bis(2,3-dibromopropyl ether) (TBBPS-BDBPE), including TBBPS mono(allyl ether) (TBBPS-MAE), TBBPS mono(2-bromoallyl ether) (TBBPS-MBAE) and TBBPS mono(2,3-dibromopropyl ether) (TBBPS-MDBPE) as novel brominated contaminants. Meanwhile, the mass spectra and analytical method for determination of TBBPS-BDBPE byproducts were presented for the first time. The detectable concentrations (dry weight) of TBBPS-MAE, TBBPS-MBAE and TBBPS-MDBPE were in the ranges 28-394 μg/g in technical TBBPS-BDBPE and 0.1-4.1 ng/g in mollusks collected from the Chinese Bohai Sea. The detection frequencies in mollusk samples were 5%, 39%, 95% for TBBPS-MAE, TBBPS-MBAE and TBBPS-MDBPE, respectively, indicating their prevailing in the environment. The results showed that they could be co-produced and leaked into the environment with production process, and might be more bioaccumulative and toxic than TBBPS-BDBPE. Therefore, the production and use of TBBPS derivatives lead to unexpected contamination to the surrounding environment. This study also provided an effective approach for identification of novel contaminants in the environment with synthesized standards and Orbitrap high resolution mass spectrometry.

  13. [Secondary metabolites, lethality and antimicrobial activity of extracts from three corals and three marine mollusks from Sucre, Venezuela].

    PubMed

    Ordaz, Gabriel; D'Armas, Haydelba; Yáñez, Dayanis; Hernández, Juan; Camacho, Angel

    2010-06-01

    The study of biochemical activity of extracts obtained from marine organisms is gaining interest as some have proved to have efficient health or industrial applications. To evaluate lethality and antimicrobial activities, some chemical tests were performed on crude extracts of the octocorals Eunicea sp., Muricea sp. and Pseudopterogorgia acerosa and the mollusks Pteria colymbus, Phyllonotus pomum and Chicoreus brevifrons, collected in Venezuelan waters. The presence of secondary metabolites like alkaloids, unsaturated sterols and pentacyclic triterpenes in all invertebrates, was evidenced. Additionally, sesquiterpenlactones, saponins, tannins, cyanogenic and cardiotonic glycosides were also detected in some octocoral extracts, suggesting that biosynthesis of these metabolites is typical in this group. From the lethality bioassays, all extracts resulted lethal to Artemia salina (LC50<1000 microg/ml) with an increased of lethal activity with exposition time. P. pomum extract showed the highest lethality rate (LC50=46.8 microg/ml). Compared to the octocorals, mollusks extracts displayed more activity and a greater action spectrum against different bacterial strains, whereas octocorals also inhibited some fungi strains growth. Staphylococcus aureus was the most susceptible to the antimicrobial power of the extracts (66.7%), whereas Pseudomonas aeruginosa, Candida albicans and Aspergillus niger were not affected. The antibiosis shown by marine organisms extracts indicates that some of their biosynthesized metabolites are physiologically active, and may have possible cytotoxic potential or as a source of antibiotic components. PMID:20527468

  14. Heavy metal effects on cellular shape changes, cleavage, and larval development of the marine gastropod mollusk, (Ilyanassa obsoleta Say)

    SciTech Connect

    Conrad, G.W.

    1988-07-01

    The spawning areas for many marine invertebrates are in intertidal zones which can be exposed to surface water run-off containing heavy metals. The cellular shape changes and cleavage patterns of Ilyanassa embryos greatly resemble those of bivalve mollusks, such as Mytilus edulis, that occur in the same intertidal areas. Determining the concentrations of heavy metals tolerated by the molluscan embryos inhabiting such clam and mussel beds therefore is of some economic significance. Moreover, such research may providedata on the heavy metal effects on the cytoskeleton. There is increasing evidence that components of the cytoskeleton, directly or indirectly, are targets for toxic agents. Polar lobe formation is a cellular shape change that resembles cytokinesis. It is seen in the fertilized eggs of many marine mollusks. Recent data with inorganic and organic Ca/sup 2 +/ antagonists suggest that both polar lobe formation and cytokinesis utilize Ca/sup 2 +/ released from sequestered, intracellular sites. Both of these cellular constrictions are associated with microfilaments and are preceded by activation steps requiring microtubules. The data presented below suggest that several heavy metals affect the microfilament-dependent steps.

  15. Characterization of Three Tetrabromobisphenol-S Derivatives in Mollusks from Chinese Bohai Sea: A Strategy for Novel Brominated Contaminants Identification

    PubMed Central

    Liu, Ai-feng; Tian, Yong; Yin, Nuo-ya; Yu, Miao; Qu, Guang-bo; Shi, Jian-bo; Du, Yu-guo; Jiang, Gui-bin

    2015-01-01

    Identification of novel brominated contaminants in the environment, especially the derivatives and byproducts of brominated flame retardants (BFRs), has become a wide concern because of their adverse effects on human health. Herein, we qualitatively and quantitatively identified three byproducts of tetrabromobisphenol-S bis(2,3-dibromopropyl ether) (TBBPS-BDBPE), including TBBPS mono(allyl ether) (TBBPS-MAE), TBBPS mono(2-bromoallyl ether) (TBBPS-MBAE) and TBBPS mono(2,3-dibromopropyl ether) (TBBPS-MDBPE) as novel brominated contaminants. Meanwhile, the mass spectra and analytical method for determination of TBBPS-BDBPE byproducts were presented for the first time. The detectable concentrations (dry weight) of TBBPS-MAE, TBBPS-MBAE and TBBPS-MDBPE were in the ranges 28–394 μg/g in technical TBBPS-BDBPE and 0.1–4.1 ng/g in mollusks collected from the Chinese Bohai Sea. The detection frequencies in mollusk samples were 5%, 39%, 95% for TBBPS-MAE, TBBPS-MBAE and TBBPS-MDBPE, respectively, indicating their prevailing in the environment. The results showed that they could be co-produced and leaked into the environment with production process, and might be more bioaccumulative and toxic than TBBPS-BDBPE. Therefore, the production and use of TBBPS derivatives lead to unexpected contamination to the surrounding environment. This study also provided an effective approach for identification of novel contaminants in the environment with synthesized standards and Orbitrap high resolution mass spectrometry. PMID:26130450

  16. Automatic basal slice detection for cardiac analysis

    NASA Astrophysics Data System (ADS)

    Paknezhad, Mahsa; Marchesseau, Stephanie; Brown, Michael S.

    2016-03-01

    Identification of the basal slice in cardiac imaging is a key step to measuring the ejection fraction (EF) of the left ventricle (LV). Despite research on cardiac segmentation, basal slice identification is routinely performed manually. Manual identification, however, has been shown to have high inter-observer variability, with a variation of the EF by up to 8%. Therefore, an automatic way of identifying the basal slice is still required. Prior published methods operate by automatically tracking the mitral valve points from the long-axis view of the LV. These approaches assumed that the basal slice is the first short-axis slice below the mitral valve. However, guidelines published in 2013 by the society for cardiovascular magnetic resonance indicate that the basal slice is the uppermost short-axis slice with more than 50% myocardium surrounding the blood cavity. Consequently, these existing methods are at times identifying the incorrect short-axis slice. Correct identification of the basal slice under these guidelines is challenging due to the poor image quality and blood movement during image acquisition. This paper proposes an automatic tool that focuses on the two-chamber slice to find the basal slice. To this end, an active shape model is trained to automatically segment the two-chamber view for 51 samples using the leave-one-out strategy. The basal slice was detected using temporal binary profiles created for each short-axis slice from the segmented two-chamber slice. From the 51 successfully tested samples, 92% and 84% of detection results were accurate at the end-systolic and the end-diastolic phases of the cardiac cycle, respectively.

  17. Epidemiology of basal-like breast cancer

    PubMed Central

    Millikan, Robert C.; Newman, Beth; Tse, Chiu-Kit; Moorman, Patricia G.; Conway, Kathleen; Smith, Lisa V.; Labbok, Miriam H.; Geradts, Joseph; Bensen, Jeannette T.; Jackson, Susan; Nyante, Sarah; Livasy, Chad; Carey, Lisa; Earp, H. Shelton; Perou, Charles M.

    2008-01-01

    Risk factors for the newly identified “intrinsic” breast cancer subtypes (luminal A, luminal B, basal-like and human epidermal growth factor receptor 2-positive/estrogen receptor-negative) were determined in the Carolina Breast Cancer Study, a population-based, case–control study of African-American and white women. Immunohistochemical markers were used to subtype 1,424 cases of invasive and in situ breast cancer, and case subtypes were compared to 2,022 controls. Luminal A, the most common subtype, exhibited risk factors typically reported for breast cancer in previous studies, including inverse associations for increased parity and younger age at first full-term pregnancy. Basal-like cases exhibited several associations that were opposite to those observed for luminal A, including increased risk for parity and younger age at first term full-term pregnancy. Longer duration breastfeeding, increasing number of children breastfed, and increasing number of months breastfeeding per child were each associated with reduced risk of basal-like breast cancer, but not luminal A. Women with multiple live births who did not breastfeed and women who used medications to suppress lactation were at increased risk of basal-like, but not luminal A, breast cancer. Elevated waist-hip ratio was associated with increased risk of luminal A in postmenopausal women, and increased risk of basal-like breast cancer in pre- and postmenopausal women. The prevalence of basal-like breast cancer was highest among premenopausal African-American women, who also showed the highest prevalence of basal-like risk factors. Among younger African-American women, we estimate that up to 68% of basal-like breast cancer could be prevented by promoting breastfeeding and reducing abdominal adiposity. PMID:17578664

  18. Schwann cell basal lamina and nerve regeneration.

    PubMed

    Ide, C; Tohyama, K; Yokota, R; Nitatori, T; Onodera, S

    1983-12-12

    Nerve segments approximately 7 mm long were excised from the predegenerated sciatic nerves of mice, and treated 5 times by repetitive freezing and thawing to kill the Schwann cells. Such treated nerve segments were grafted into the original places so as to be in contact with the proximal stumps. The animals were sacrificed 1, 2, 3, 5, 7 and 10 days after the grafting. The grafts were examined by electron microscopy in the middle part of the graft, i.e. 3-4 mm distal to the proximal end and/or near the proximal and distal ends of the graft. In other instances, the predegenerated nerve segments were minced with a razor blade after repetitive freezing and thawing. Such minced nerves were placed in contact with the proximal stumps of the same nerves. The animals were sacrificed 10 days after the grafting. Within 1-2 days after grafting, the dead Schwann cells had disintegrated into fragments. They were then gradually phagocytosed by macrophages. The basal laminae of Schwann cells, which were not attacked by macrophages, remained as empty tubes (basal lamina scaffolds). In the grafts we examined, no Schwann cells survived the freezing and thawing process. The regenerating axons always grew out through such basal lamina scaffolds, being in contact with the inner surface of the basal lamina (i.e. the side originally facing the Schwann cell plasma membrane). No axons were found outside of the scaffolds. One to two days after grafting, the regenerating axons were not associated with Schwann cells, but after 5-7 days they were accompanied by Schwann cells which were presumed to be migrating along axons from the proximal stumps. Ten days after grafting, proliferating Schwann cells observed in the middle part of the grafts had begun to sort out axons. In the grafts of minced nerves, the fragmented basal laminae of the Schwann cells re-arranged themselves into thicker strands or small aggregations of basal laminae. The regenerating axons, without exception, attached to one side

  19. Extrastriatal Dopaminergic Circuits of the Basal Ganglia

    PubMed Central

    Rommelfanger, Karen S.; Wichmann, Thomas

    2010-01-01

    The basal ganglia are comprised of the striatum, the external and internal segment of the globus pallidus (GPe and GPi, respectively), the subthalamic nucleus (STN), and the substantia nigra pars compacta and reticulata (SNc and SNr, respectively). Dopamine has long been identified as an important modulator of basal ganglia function in the striatum, and disturbances of striatal dopaminergic transmission have been implicated in diseases such as Parkinson's disease (PD), addiction and attention deficit hyperactivity disorder. However, recent evidence suggests that dopamine may also modulate basal ganglia function at sites outside of the striatum, and that changes in dopaminergic transmission at these sites may contribute to the symptoms of PD and other neuropsychiatric disorders. This review summarizes the current knowledge of the anatomy, functional effects and behavioral consequences of the dopaminergic innervation to the GPe, GPi, STN, and SNr. Further insights into the dopaminergic modulation of basal ganglia function at extrastriatal sites may provide us with opportunities to develop new and more specific strategies for treating disorders of basal ganglia dysfunction. PMID:21103009

  20. [Osphradial chemosensory organ as a probable trigger of the cardiac system adaptive reaction to the effect of heavy metals in aquatic mollusks].

    PubMed

    Kamardin, N N; Lubimtsev, V A; Kornienko, E L; Udalova, G P; Kholodkevich, S V; Apostolov, S A

    2015-01-01

    The responses of osphradium in the fresh-water mollusk Viviparus sp. and single osphradial neurons in the pond snail Lymnaea stagnalis to L-glutamine and L-asparagine as well as the changes in these responses under the effect of heavy metals (Cu, Cd) were recorded electrophysiologically. The functional connections of osphradium with the identified neurons of the central pattern generator of respiratory movements and cardiac activity as well as the modification of these connections under the effect of short-term application of HgCl2 solution on the snail's osphradium were investigated. The cardiac rhythm in the mollusk Littorina littorea under the effect of Cu ions was registered non-invasively in long-lasting experiments. The dose-dependent short-term effects of heavy metals changes after osphradium injury were revealed. The implication of osphradium in adaptive reactions of the cardiac system in aquatic mollusks to the environmental heavy metal pollution is suggested. The dependence of cardiac rhythm on the degree of accumulation of copper ions in the mollusk tissues was detected. The results obtained are essential for unraveling neural mechanisms and pathways allowing heavy metals to affect the functional state of hydrobionts, particularly, the cardiac activity frequency characteristics of which are widely used as informative biomarkers to assess physiological condition of aquatic invertebrates. PMID:25859605

  1. Determination of perfluorinated compounds in mollusks by matrix solid-phase dispersion and liquid chromatography-tandem mass spectrometry.

    PubMed

    Villaverde-de-Sáa, Eugenia; Quintana, José Benito; Rodil, Rosario; Ferrero-Refojos, Raúl; Rubí, Elisa; Cela, Rafael

    2012-01-01

    Perfluorinated compounds (PFCs) have been used for over 40 years in different commercial and industrial applications mainly as surfactants and surface protectors and have become an important class of marine emerging pollutants. This study presents the development and validation of a new analytical method to determine the simultaneous presence of eight PFCs in different kinds of mollusks using matrix solid-phase dispersion (MSPD) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Simplicity of the analytical procedure, low volume of solvent and quantity of sample required, low global price, and integration of extraction and clean-up into a single step, are the most important advantages of the developed methodology. Solvent, solid support (dispersing agent), clean-up sorbent, and their amounts were optimized by means of an experimental design. In the final method, 0.5 g of sample are dispersed with 0.2 g of diatomaceous earth and transferred into a polypropylene syringe containing 4 g of silica as clean-up sorbent. Then, analytes are eluted with 20 mL of acetonitrile. The extract is finally concentrated to a final volume of 0.5 mL in methanol, avoiding extract dryness in order to prevent evaporation losses and injected in the LC-MS/MS. The combination of this MSPD protocol with LC-MS/MS afforded detection limits from 0.05 to 0.3 ng g(-1). Also, a good linearity was established for the eight PFCs in the range from limit of quantification (LOQ) to 500 ng mL(-1) with R(2) > 0.9917. The recovery of the method was studied with three types of spiked mollusk and was in the 64-126% range. Moreover, a mussel sample was spiked and aged for more than 1 month and analyzed by the developed method and a reference method, ion-pair extraction, for comparison, producing both methods statistically equal concentration values. The method was finally applied to the determination of PFCs in different kinds of mollusks revealing concentrations up to 8.3 ng g(-1) for

  2. Epithelial-Mesenchymal Transition Protein Expression in Basal Cell Adenomas and Basal Cell Adenocarcinomas.

    PubMed

    Tesdahl, Brennan A; Wilson, Thomas C; Hoffman, Henry T; Robinson, Robert A

    2016-06-01

    Basal cell adenomas and basal cell adenocarcinomas show marked histomorphologic similarity and are separated microscopically primarily by the invasive characteristics of the adenocarcinomas. We wished to explore potential differences in the expression of epithelial-mesenchymal transition associated proteins in these two tumor types. A tissue microarray was constructed utilizing 29 basal cell adenomas and 16 basal cell adenocarcinomas. Immunohistochemical expression of E-cadherin, beta-catenin, Twist 1 and vimentin were investigated. Both tumors expressed all proteins in a relatively similar manner. Nuclear beta-catenin was essentially limited to the abluminal cell populations in both tumor types. E-cadherin was limited largely to luminal locations but was more prevalent in the adenocarcinomas as compared to the adenomas. Primarily abluminal expression for vimentin was seen, sometimes present in an apical dot-like pattern. Distinct populations of cellular expression of these four markers of epithelial mesenchymal transition were present but were similar in locations in both tumors with no patterns discerned to separate basal cell adenoma from basal cell adenocarcinoma. Given these findings, the mechanisms by which basal cell adenocarcinoma is able to invade while its counterpart, basal cell adenoma can not, may be more complex than in other tumor types. PMID:26442856

  3. Shaping Action Sequences in Basal Ganglia Circuits

    PubMed Central

    Jin, Xin; Costa, Rui M

    2015-01-01

    Many behaviors necessary for organism survival are learned anew and become organized as complex sequences of actions. Recent studies suggest that cortico-basal ganglia circuits are important for chunking isolated movements into precise and robust action sequences that permit the achievement of particular goals. During sequence learning many neurons in the basal ganglia develop sequence-related activity - related to the initiation, execution, and termination of sequences - suggesting that action sequences are processed as action units. Corticostriatal plasticity is critical for the crystallization of action sequences, and for the development of sequence-related neural activity. Furthermore, this sequence-related activity is differentially expressed in direct and indirect basal ganglia pathways. These findings have implications for understanding the symptoms associated with movement and psychiatric disorders. PMID:26189204

  4. Can basal magma oceans generate magnetic fields?

    NASA Astrophysics Data System (ADS)

    Stegman, D. R.; Ziegler, L. B.; Davies, C.

    2015-12-01

    Earth's magnetic field is very old, with recent data now showing the field possibly extended back to 4.1 billion years ago (Tarduno et al., Science, 2015). Yet, based upon our current knowledge there are difficulties in sustained a core dynamo over most of Earth's history. Moreover, recent estimates of thermal and electrical conductivity of liquid iron at core conditions from mineral physics experiments indicate that adiabatic heat flux is approximately 15 TW, nearly 3 times larger than previously thought, exacerbating difficulties for driving a core dynamo by convective core cooling alone throughout Earth history. A long-lived basal magma ocean in the lowermost mantle has been proposed to exist in the early Earth, surviving perhaps into the Archean. While the modern, solid lower mantle is an electromagnetic insulator, electrical conductivities of silicate melts are known to be higher, though as yet they are unconstrained for lowermost mantle conditions. Here we explore the geomagnetic consequences of a basal magma ocean layer for a range of possible electrical conductivities. For the highest electrical conductivities considered, we find a basal magma ocean could be a primary dynamo source region. This would suggest the proposed three magnetic eras observed in paleomagnetic data originate from distinct sources for dynamo generation: from 4.5-2.45 Ga within a basal magma ocean, from 2.25-0.4 Ga within a superadiabatically cooled liquid core, and from 0.4-present within a quasi-adiabatic core that includes a solidifying inner core. We have extended this work by developing a new code, Dynamantle, which is a model with an entropy-based approach, similar to those commonly used in core dynamics models. We present new results using this code to assess the conditions under which basal magma oceans can generate positive ohmic dissipation. This is more generally useful than just considering the early Earth, but also for many silicate exoplanets in which basal magma oceans

  5. [Shell Variability of the Terrestrial Mollusk Chondrula tridens (Pulmonata, Enidae) in the Forest-Steppe Zone of the Volga Upland].

    PubMed

    Komarova, E V; Smirnov, D G; Stoiko, T G

    2015-01-01

    Shell variability of the steppe mollusk Chondrula tridens from 18 micropopulations in the forest-steppe zone of the Volga Upland was studied. It was found that larger specimens of Ch. tridens with well-developed teeth inhabit the central and eastern parts of the territory. Specimens in the northwestern part of the upland are characterized by small shells, the highest degree of roundness, and mostly reduced teeth in the mouth. The main factors that determine variability in the size and proportions of shells are the average daily temperatures increasing from the northwest to the south, the reduction in the total precipitation, the decrease in the soil moisture content, and, possibly, the increased content of carbonates in the soil. PMID:26852480

  6. Heavy metals in bivalve mollusks collected from Da-Peng Bay Lagoon in south-southwestern Taiwan.

    PubMed

    Shue, Meei-Fang; Chen, Wen-Der; Su, Chia-Chi; Lu, Ming-Chun

    2014-01-01

    In this study, concentrations of several heavy metals (Cu, Pb, Zn, Ni, Cr, and Cd) were measured in Katelysia hiantina, Anomalocardia squamosa, Perna viridis, Anadara antiquata, Paphia undulata, and Sanguinolaria diphos bivalve mollusks from Da-Peng Bay Lagoon near the south-southwestern coast of Taiwan. The metal pollution index (MPI) values were highest and lowest in winter and autumn, respectively. The MPI value in the viscera of P. viridis was higher than in muscles. In all four seasons, Zn concentrations in viscera and muscles of P. viridis were higher than for other metals. The capacities of A. squamosa to accumulate the concentrations of Cu, Ni, and Cr and of A. antiquata to accumulate concentrations of Pb, Zn, and Cd were significant. Analytical results suggested that A. squamosa and A. antiquata may be used as bioindicators for monitoring Cu, Ni, Cr, Pb, Zn, and Cd heavy-metal pollution in Da-Peng Bay Lagoon throughout the year. PMID:24555680

  7. Cloning and characterization of an actin gene of Chlamys farreri and the phylogenetic analysis of mollusk actins

    NASA Astrophysics Data System (ADS)

    Ma, Hongming; Mai, Kangsen; Liufu, Zhiguo; Xu, Wei

    2007-07-01

    An actingene (CfACTI) was cloned by using RT-PCR, 3’ and 5’RACE from hemocytes of the sea scallop Chlamys farreri. The full length of the transcript is 1 535 bp, which contains a long 3’ un-translated region of 436bp and 59bp of a 5’ un-translated sequence. The open reading frame encodes a polypeptide of 376 amino acids. Sequence comparisons indicated that CfACTI is more closely related to vertebrate cytoplasmic actins than muscle types. Phylogenetic analysis showed that molluscan actins could be generally divided into two categories: muscle and cytoplasmic, although both are similar to vertebrate cytoplasmic actins. It was also inferred that different isotypes existed in muscle or cytoplasma in mollusks. The genomic sequence of CfACTI was cloned and sequenced. Only one intron was detected: it was located between codons 42 and 43 and different from vertebrate actin genes.

  8. The connectome of the basal ganglia.

    PubMed

    Schmitt, Oliver; Eipert, Peter; Kettlitz, Richard; Leßmann, Felix; Wree, Andreas

    2016-03-01

    The basal ganglia of the laboratory rat consist of a few core regions that are specifically interconnected by efferents and afferents of the central nervous system. In nearly 800 reports of tract-tracing investigations the connectivity of the basal ganglia is documented. The readout of connectivity data and the collation of all the connections of these reports in a database allows to generate a connectome. The collation, curation and analysis of such a huge amount of connectivity data is a great challenge and has not been performed before (Bohland et al. PloS One 4:e7200, 2009) in large connectomics projects based on meta-analysis of tract-tracing studies. Here, the basal ganglia connectome of the rat has been generated and analyzed using the consistent cross-platform and generic framework neuroVIISAS. Several advances of this connectome meta-study have been made: the collation of laterality data, the network-analysis of connectivity strengths and the assignment of regions to a hierarchically organized terminology. The basal ganglia connectome offers differences in contralateral connectivity of motoric regions in contrast to other regions. A modularity analysis of the weighted and directed connectome produced a specific grouping of regions. This result indicates a correlation of structural and functional subsystems. As a new finding, significant reciprocal connections of specific network motifs in this connectome were detected. All three principal basal ganglia pathways (direct, indirect, hyperdirect) could be determined in the connectome. By identifying these pathways it was found that there exist many further equivalent pathways possessing the same length and mean connectivity weight as the principal pathways. Based on the connectome data it is unknown why an excitation pattern may prefer principal rather than other equivalent pathways. In addition to these new findings the local graph-theoretical features of regions of the connectome have been determined. By

  9. Repeated sampling of individual bivalve mollusks I: intraindividual variability and consequences for haemolymph constituents of the Manila clam, Ruditapes philippinarum.

    PubMed

    Ford, Susan E; Paillard, Christine

    2007-08-01

    Components of the haemolymph are understood to constitute the internal defense system of bivalve mollusks and their levels are often considered to be indicators of "health"; however, relatively little proof exists of the role that these elements play in the success or failure of defense against a pathogen. A change associated with infection may be the consequence of disease rather than a measure of the capacity to respond effectively to a pathogen. One way to assess whether haemocyte or serum-component concentrations are related to resistance to microbial infection is to sample individuals over time, both before and after they are experimentally or naturally infected. But sampling itself may alter the parameter being assessed. In addition, interindividual variation is large and the degree of intraindividual variation over time is largely unknown. To evaluate intra- vs interindividual variability measured over time and to assess the effects of repeated sampling, we subjected Manila clams, Ruditapes philippinarum, to multiple haemolymph samplings during both field and laboratory experiments, and measured four parameters: haemocyte density, protein concentration, and the activities of leucine amino peptidase and DOPA-oxidase. A repeated-measures ANOVA indicated that individuals with high or low levels at one sampling, tended to have high or low levels, respectively, at the other sampling times. Furthermore, the index of individuality, which is the ratio of intra- to interindividual variability, for these four parameters was comparable to that for human serum components. Repeated sampling had no measured effect on field-deployed clams, which were sampled at intervals of 1-3 months, but significantly depressed values in laboratory-held clams sampled at 1-month intervals. Results demonstrated relative intraindividual constancy in the measured variables and suggested that minimizing sample frequency and volume, and maintaining animals in a comparatively natural

  10. Reconstructing past upwelling intensity and the seasonal dynamics of primary productivity along the Peruvian coastline from mollusk shell stable isotopes

    NASA Astrophysics Data System (ADS)

    Sadler, James; Carré, Matthieu; Azzoug, Moufok; Schauer, Andrew J.; Ledesma, Jesus; Cardenas, Fredy; Chase, Brian M.; Bentaleb, Ilhem; Muller, Serge D.; Mandeng, Magloire; Rohling, Eelco J.; Sachs, Julian P.

    2012-01-01

    We present here a potential new method to evaluate past variations of the mean intensity of Peruvian coastal upwelling and of the seasonal timing of phytoplankton blooms. This method uses a combination of the monthly carbon and oxygen isotopic signals preserved in fossil mollusk shells, and a series of corrections to extract the variations of the dissolved inorganic carbon (DIC) δ13C. Based on the analysis of five shell samples (85 shells in total) from the southern Peruvian coast, we suggest that the mean coastal upwelling intensity can be determined from a linear relationship between average values of corrected shell δ13C and δ18O. This new potential proxy would bring additional independent information valuable to interpret paleoproductivity changes reconstructed from marine sediment of the nearby continental shelf. Results obtained on fossil samples from the middle Holocene show an increase in upwelling intensity during this period associated to a spatial reorganization of upwelling centers along the South Peruvian coast. At the seasonal scale, corrected shell δ13C enrichment indicates a phytoplankton bloom. Seasonal timing of phytoplankton blooms can be estimated by the lag with the annual temperature cycle reproduced by shell δ18O monthly variations. The results obtained with two modern shell samples indicate phytoplankton blooms occurring during summer and fall, consistently with in situ productivity observations. Our method relies on revisited assumptions about the influence of temperature and metabolism in mollusk shell δ13C. We further discussed the validity of these assumptions and the potential implications for the interpretation of similar data sets.

  11. 6-bromohypaphorine from marine nudibranch mollusk Hermissenda crassicornis is an agonist of human α7 nicotinic acetylcholine receptor.

    PubMed

    Kasheverov, Igor E; Shelukhina, Irina V; Kudryavtsev, Denis S; Makarieva, Tatyana N; Spirova, Ekaterina N; Guzii, Alla G; Stonik, Valentin A; Tsetlin, Victor I

    2015-03-01

    6-Bromohypaphorine (6-BHP) has been isolated from the marine sponges Pachymatisma johnstoni, Aplysina sp., and the tunicate Aplidium conicum, but data on its biological activity were not available. For the nudibranch mollusk Hermissenda crassicornis no endogenous compounds were known, and here we describe the isolation of 6-BHP from this mollusk and its effects on different nicotinic acetylcholine receptors (nAChR). Two-electrode voltage-clamp experiments on the chimeric α7 nAChR (built of chicken α7 ligand-binding and glycine receptor transmembrane domains) or on rat α4β2 nAChR expressed in Xenopus oocytes revealed no action of 6-BHP. However, in radioligand analysis, 6-BHP competed with radioiodinated α-bungarotoxin for binding to human α7 nAChR expressed in GH4C1 cells (IC50 23 ± 1 μM), but showed no competition on muscle-type nAChR from Torpedo californica. In Ca2+-imaging experiments on the human α7 nAChR expressed in the Neuro2a cells, 6-BHP in the presence of PNU120596 behaved as an agonist (EC50 ~80 μM). To the best of our knowledge, 6-BHP is the first low-molecular weight compound from marine source which is an agonist of the nAChR subtype. This may have physiological importance because H. crassicornis, with its simple and tractable nervous system, is a convenient model system for studying the learning and memory processes. PMID:25775422

  12. 6-Bromohypaphorine from Marine Nudibranch Mollusk Hermissenda crassicornis is an Agonist of Human α7 Nicotinic Acetylcholine Receptor

    PubMed Central

    Kasheverov, Igor E.; Shelukhina, Irina V.; Kudryavtsev, Denis S.; Makarieva, Tatyana N.; Spirova, Ekaterina N.; Guzii, Alla G.; Stonik, Valentin A.; Tsetlin, Victor I.

    2015-01-01

    6-Bromohypaphorine (6-BHP) has been isolated from the marine sponges Pachymatisma johnstoni, Aplysina sp., and the tunicate Aplidium conicum, but data on its biological activity were not available. For the nudibranch mollusk Hermissenda crassicornis no endogenous compounds were known, and here we describe the isolation of 6-BHP from this mollusk and its effects on different nicotinic acetylcholine receptors (nAChR). Two-electrode voltage-clamp experiments on the chimeric α7 nAChR (built of chicken α7 ligand-binding and glycine receptor transmembrane domains) or on rat α4β2 nAChR expressed in Xenopus oocytes revealed no action of 6-BHP. However, in radioligand analysis, 6-BHP competed with radioiodinated α-bungarotoxin for binding to human α7 nAChR expressed in GH4C1 cells (IC50 23 ± 1 μM), but showed no competition on muscle-type nAChR from Torpedo californica. In Ca2+-imaging experiments on the human α7 nAChR expressed in the Neuro2a cells, 6-BHP in the presence of PNU120596 behaved as an agonist (EC50 ~80 μM). To the best of our knowledge, 6-BHP is the first low-molecular weight compound from marine source which is an agonist of the nAChR subtype. This may have physiological importance because H. crassicornis, with its simple and tractable nervous system, is a convenient model system for studying the learning and memory processes. PMID:25775422

  13. Cm-p5: an antifungal hydrophilic peptide derived from the coastal mollusk Cenchritis muricatus (Gastropoda: Littorinidae)

    PubMed Central

    López-Abarrategui, Carlos; McBeth, Christine; Mandal, Santi M.; Sun, Zhenyu J.; Heffron, Gregory; Alba-Menéndez, Annia; Migliolo, Ludovico; Reyes-Acosta, Osvaldo; García-Villarino, Mónica; Nolasco, Diego O.; Falcão, Rosana; Cherobim, Mariana D.; Dias, Simoni C.; Brandt, Wolfgang; Wessjohann, Ludger; Starnbach, Michael; Franco, Octavio L.; Otero-González, Anselmo J.

    2015-01-01

    Antimicrobial peptides form part of the first line of defense against pathogens for many organisms. Current treatments for fungal infections are limited by drug toxicity and pathogen resistance. Cm-p5 (SRSELIVHQRLF), a peptide derived from the marine mollusk Cenchritis muricatus peptide Cm-p1, has a significantly increased fungistatic activity against pathogenic Candida albicans (minimal inhibitory concentration, 10 µg/ml; EC50, 1.146 µg/ml) while exhibiting low toxic effects against a cultured mammalian cell line. Cm-p5 as characterized by circular dichroism and nuclear magnetic resonance revealed an α-helical structure in membrane-mimetic conditions and a tendency to random coil folding in aqueous solutions. Additional studies modeling Cm-p5 binding to a phosphatidylserine bilayer in silico and isothermal titration calorimetry using lipid monophases demonstrated that Cm-p5 has a high affinity for the phospholipids of fungal membranes (phosphatidylserine and phosphatidylethanolamine), only moderate interactions with a mammalian membrane phospholipid, low interaction with ergosterol, and no interaction with chitin. Adhesion of Cm-p5 to living C. albicans cells was confirmed by fluorescence microscopy with FITC-labeled peptide. In a systemic candidiasis model in mice, intraperitoneal administration of Cm-p5 was unable to control the fungal kidney burden, although its low amphiphaticity could be modified to generate new derivatives with improved fungicidal activity and stability.—López-Abarrategui, C., McBeth, C., Mandal, S. M., Sun, Z. J., Heffron, G., Alba-Menéndez, A., Migliolo, L., Reyes-Acosta, O., García-Villarino, M., Nolasco, D. O., Falcão, R., Cherobim, M. D., Dias, S. C., Brandt, W., Wessjohann, L., Starnbach, M., Franco, O. L., Otero-González, A. J. Cm-p5: an antifungal hydrophilic peptide derived from the coastal mollusk Cenchritis muricatus (Gastropoda: Littorinidae). PMID:25921828

  14. Enhancing Basal Vocabulary Instruction in Kindergarten

    ERIC Educational Resources Information Center

    Lenfest, Ashleigh; Reed, Deborah K.

    2015-01-01

    To enhance the basal vocabulary instruction for kindergarten students at risk for reading difficulties, lessons provided in typical curricular materials can be supplemented with instructional elements derived from research. This article addresses how teachers can add 15 minutes of higher order instructional activities to daily reading lessons to…

  15. Basal ganglia germinoma with progressive cerebral hemiatrophy.

    PubMed

    Liu, E; Robertson, R L; du Plessis, A; Pomeroy, S L

    1999-04-01

    The authors describe a 7-year-old Chinese-American female with a germinoma of the basal ganglia who presented with progressive hemiparesis and cerebral hemiatrophy. The additional finding of markedly elevated antiphospholipid antibodies suggests the possibility of an autoimmune pathogenesis for the progressive cerebral atrophy, as well as the later development of cognitive decline, tics, and obsessive-compulsive behaviors. PMID:10328283

  16. Basal Ganglia Germinoma in an Adult.

    PubMed

    Vialatte de Pémille, Clément; Bielle, Franck; Mokhtari, Karima; Kerboua, Esma; Alapetite, Claire; Idbaih, Ahmed

    2016-08-01

    Intracranial germinoma is a rare primary brain cancer, usually located within the midline and mainly affecting Asian pediatric patients. Interestingly, we report here the peculiar case of a young North-African adult patient suffering from a basal ganglia germinoma without the classical ipsilateral cerebral hemiatrophy associated with this location. PMID:27241091

  17. Reward functions of the basal ganglia.

    PubMed

    Schultz, Wolfram

    2016-07-01

    Besides their fundamental movement function evidenced by Parkinsonian deficits, the basal ganglia are involved in processing closely linked non-motor, cognitive and reward information. This review describes the reward functions of three brain structures that are major components of the basal ganglia or are closely associated with the basal ganglia, namely midbrain dopamine neurons, pedunculopontine nucleus, and striatum (caudate nucleus, putamen, nucleus accumbens). Rewards are involved in learning (positive reinforcement), approach behavior, economic choices and positive emotions. The response of dopamine neurons to rewards consists of an early detection component and a subsequent reward component that reflects a prediction error in economic utility, but is unrelated to movement. Dopamine activations to non-rewarded or aversive stimuli reflect physical impact, but not punishment. Neurons in pedunculopontine nucleus project their axons to dopamine neurons and process sensory stimuli, movements and rewards and reward-predicting stimuli without coding outright reward prediction errors. Neurons in striatum, besides their pronounced movement relationships, process rewards irrespective of sensory and motor aspects, integrate reward information into movement activity, code the reward value of individual actions, change their reward-related activity during learning, and code own reward in social situations depending on whose action produces the reward. These data demonstrate a variety of well-characterized reward processes in specific basal ganglia nuclei consistent with an important function in non-motor aspects of motivated behavior. PMID:26838982

  18. TEMPORAL VARIABILITY IN BASAL ISOPRENE EMISSION FACTOR

    EPA Science Inventory

    Seasonal variability in basal isoprene emission factor (micrograms C /g hr or nmol/ m2 sec, leaf temperature at 30 degrees C and photosynthetically active radiation (PAR) at 1000 micromol/ m2 sec) was studied during the 1998 growing season at Duke Forest in the North Carolina Pie...

  19. How Basal Reading Texts Affect Children's Writing.

    ERIC Educational Resources Information Center

    Eckhoff, Barbara L.

    A study investigated how children's writing reflects the syntactic complexity, style, and format of their basal readers. Subjects were 116 students drawn from 10 second, third, and fourth grade classrooms in two different schools located near Boston, Massachusetts. A matched group design was used, and students using a form of the "Ginn" basal…

  20. Functional anatomy of thalamus and basal ganglia.

    PubMed

    Herrero, María-Trinidad; Barcia, Carlos; Navarro, Juana Mari

    2002-08-01

    THALAMUS: The human thalamus is a nuclear complex located in the diencephalon and comprising of four parts (the hypothalamus, the epythalamus, the ventral thalamus, and the dorsal thalamus). The thalamus is a relay centre subserving both sensory and motor mechanisms. Thalamic nuclei (50-60 nuclei) project to one or a few well-defined cortical areas. Multiple cortical areas receive afferents from a single thalamic nucleus and send back information to different thalamic nuclei. The corticofugal projection provides positive feedback to the "correct" input, while at the same time suppressing irrelevant information. Topographical organisation of the thalamic afferents and efferents is contralateral, and the lateralisation of the thalamic functions affects both sensory and motoric aspects. Symptoms of lesions located in the thalamus are closely related to the function of the areas involved. An infarction or haemorrhage thalamic lesion can develop somatosensory disturbances and/or central pain in the opposite hemibody, analgesic or purely algesic thalamic syndrome characterised by contralateral anaesthesia (or hypaesthesia), contralateral weakness, ataxia and, often, persistent spontaneous pain. BASAL GANGLIA: Basal ganglia form a major centre in the complex extrapyramidal motor system, as opposed to the pyramidal motor system (corticobulbar and corticospinal pathways). Basal ganglia are involved in many neuronal pathways having emotional, motivational, associative and cognitive functions as well. The striatum (caudate nucleus, putamen and nucleus accumbens) receive inputs from all cortical areas and, throughout the thalamus, project principally to frontal lobe areas (prefrontal, premotor and supplementary motor areas) which are concerned with motor planning. These circuits: (i) have an important regulatory influence on cortex, providing information for both automatic and voluntary motor responses to the pyramidal system; (ii) play a role in predicting future events

  1. Learning Reward Uncertainty in the Basal Ganglia.

    PubMed

    Mikhael, John G; Bogacz, Rafal

    2016-09-01

    Learning the reliability of different sources of rewards is critical for making optimal choices. However, despite the existence of detailed theory describing how the expected reward is learned in the basal ganglia, it is not known how reward uncertainty is estimated in these circuits. This paper presents a class of models that encode both the mean reward and the spread of the rewards, the former in the difference between the synaptic weights of D1 and D2 neurons, and the latter in their sum. In the models, the tendency to seek (or avoid) options with variable reward can be controlled by increasing (or decreasing) the tonic level of dopamine. The models are consistent with the physiology of and synaptic plasticity in the basal ganglia, they explain the effects of dopaminergic manipulations on choices involving risks, and they make multiple experimental predictions. PMID:27589489

  2. What do the basal ganglia do?

    PubMed

    Brown, P; Marsden, C D

    1998-06-13

    We propose that the basal ganglia support a basic attentional mechanism operating to bind input to output in the executive forebrain. Such focused attention provides the automatic link between voluntary effort, sensory input, and the calling up and operation of a sequence of motor programmes or thoughts. The physiological basis for this attentional mechanism may lie in the tendency of distributed, but related, cortical activities to synchronise in the gamma (30 to 50 Hz) band, as occurs in the visual cortex. Coherent and synchronised elements are more effective when convergence occurs during successive stages of processing, and in this way may come together to give the one gestalt or action. We suggest that the basal ganglia have a major role in facilitating this aspect of neuronal processing in the forebrain, and that loss of this function contributes to parkinsonism and abulia. PMID:9635969

  3. RFamide peptides in agnathans and basal chordates.

    PubMed

    Osugi, Tomohiro; Son, You Lee; Ubuka, Takayoshi; Satake, Honoo; Tsutsui, Kazuyoshi

    2016-02-01

    Since a peptide with a C-terminal Arg-Phe-NH2 (RFamide peptide) was first identified in the ganglia of the venus clam in 1977, RFamide peptides have been found in the nervous system of both invertebrates and vertebrates. In vertebrates, the RFamide peptide family includes gonadotropin-inhibitory hormone (GnIH), neuropeptide FF (NPFF), prolactin-releasing peptide (PrRP), pyroglutamylated RFamide peptide/26RFamide peptide (QRFP/26RFa), and kisspeptins (kiss1 and kiss2). They are involved in important functions such as the release of hormones, regulation of sexual or social behavior, pain transmission, reproduction, and feeding. In contrast to tetrapods and jawed fish, the information available on RFamide peptides in agnathans and basal chordates is limited, thus preventing further insights into the evolution of RFamide peptides in vertebrates. In this review, we focus on the previous research and recent advances in the studies on RFamide peptides in agnathans and basal chordates. In agnathans, the genes encoding GnIH, NPFF, and PrRP precursors and the mature peptides have been identified in lamprey (Petromyzon marinus) and hagfish (Paramyxine atami). Putative kiss1 and kiss2 genes have also been found in the genome database of lamprey. In basal chordates, namely, in amphioxus (Branchiostoma japonicum), a common ancestral form of GnIH and NPFF genes and their mature peptides, as well as the ortholog of the QRFP gene have been identified. The studies revealed that the number of orthologs of vertebrate RFamide peptides present in agnathans and basal chordates is greater than expected, suggesting that the vertebrate RFamide peptides might have emerged and expanded at an early stage of chordate evolution. PMID:26130238

  4. Active decorrelation in the basal ganglia.

    PubMed

    Wilson, C J

    2013-10-10

    The cytoarchitecturally-homogeneous appearance of the globus pallidus, subthalamic nucleus and substantia nigra has long been said to imply a high degree of afferent convergence and sharing of inputs by nearby neurons. Moreover, axon collaterals of neurons in the external segment of the globus pallidus and the substantia nigra pars reticulata arborize locally and make inhibitory synapses on other cells of the same type. These features suggest that the connectivity of the basal ganglia may impose spike-time correlations among the cells, and it has been puzzling that experimental studies have failed to demonstrate such correlations. One possible solution arises from studies of firing patterns in basal ganglia cells, which reveal that they are nearly all pacemaker cells. Their high rate of firing does not depend on synaptic excitation, but they fire irregularly because a dense barrage of synaptic inputs normally perturbs the timing of their autonomous activity. Theoretical and computational studies show that the responses of repetitively-firing neurons to shared input or mutual synaptic coupling often defy classical intuitions about temporal synaptic integration. The patterns of spike-timing among such neurons depend on the ionic mechanism of pacemaking, the level of background uncorrelated cellular and synaptic noise, and the firing rates of the neurons, as well as the properties of their synaptic connections. Application of these concepts to the basal ganglia circuitry suggests that the connectivity and physiology of these nuclei may be configured to prevent the establishment of permanent spike-timing relationships between neurons. The development of highly synchronous oscillatory patterns of activity in Parkinson's disease may result from the loss of pacemaking by some basal ganglia neurons, and accompanying breakdown of the mechanisms responsible for active decorrelation. PMID:23892007

  5. Basal hydraulic conditions of Ice Stream B

    NASA Technical Reports Server (NTRS)

    Engelhardt, Hermann; Kamb, Barclay

    1993-01-01

    Fifteen boreholes have been drilled to the base of Ice Stream B in the vicinity of UpB Camp. The boreholes are spread over an area of about 500 x 1000 m. Several till cores were retrieved from the bottom of the 1000-m-deep holes. Laboratory tests using a simple shear box revealed a yield strength of basal till of 2 kPa. This agrees well with in-situ measurements using a shear vane. Since the average basal shear stress of Ice Stream B with a surface slope of 0.1 degree is about 20 kPa, the ice stream cannot be supported by till that weak. Additional support for this conclusion comes from the basal water pressure that has been measured in all boreholes as soon as the hot water drill reached bottom. In several boreholes, the water pressure has been continuously monitored; in two of them, over several years. The water pressure varies but stays within 1 bar of flotation where ice overburden pressure and water pressure are equal. The ratio of water and overburden pressure lies between 0.986 and 1.002. This is an extremely high value as compared to other fast-moving ice masses; e.g., Variegated Glacier in surge has a ratio of 0.8, and Columbia Glacier - a fast-moving tidewater glacier - has a ratio of 0.9. It implies that water flow under the glacier occurs in a thin film and not in conduits that would drain away water too rapidly. It also implies that basal sliding must be very effective. Water flow under the glacier was measured in a salt-injection experiment where a salt pulse was released at the bottom of a borehole while 60 m down-glacier, the electrical resistance was measured between two other boreholes. A flow velocity of 7 mm/s was obtained.

  6. Basal cell nevus syndrome - close-up of palm (image)

    MedlinePlus

    ... skeletal abnormalities. Skin manifestations include pits in the palms and soles, and numerous basal cell carcinomas. This ... close-up of the pits found in the palm of an individual with basal cell nevus syndrome.

  7. Evaluation of microwave and ultrasound extraction procedures for arsenic speciation in bivalve mollusks by liquid chromatography-inductively coupled plasma-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Santos, Clarissa M. M.; Nunes, Matheus A. G.; Barbosa, Isa S.; Santos, Gabriel L.; Peso-Aguiar, Marlene C.; Korn, Maria G. A.; Flores, Erico M. M.; Dressler, Valderi L.

    2013-08-01

    Liquid chromatography-inductively coupled plasma-mass spectrometry (LC-ICP-MS) was used for arsenic speciation analysis in tissues of bivalve mollusks (Anomalocardia brasiliana sp. and Macoma constricta sp.). Microwave and ultrasound radiation, combined with different extraction conditions (solvent, sample amount, time, and temperature), were evaluated for As-species extraction from the mollusks' tissues. Accuracy, extraction efficiency, and the stability of As species were evaluated by analyzing certified reference materials (DORM-2, dogfish muscle; BCR-627, tuna fish tissue; and SRM 1566b, oyster tissue) and analyte recovery tests. The best conditions were found to be microwave-assisted extraction using 200 mg of samples and water at 80 °C for 6 min. The agreement of As-species concentration in samples ranged from 97% to 102%. Arsenobetaine (AsB) was the main species present in bivalve mollusk tissues, while monomethylarsonic acid (MMA) and arsenate (As(V)) were below the limit of quantification (0.001 and 0.003 μg g- 1, respectively). Two unidentified As species also were detected and quantified. The sum of the As-species concentration was in agreement (90 to 104%), with the total As content determined by ICP-MS after sample digestion.

  8. Iodothyronine deiodinase gene analysis of the Pacific oyster Crassostrea gigas reveals possible conservation of thyroid hormone feedback regulation mechanism in mollusks

    NASA Astrophysics Data System (ADS)

    Huang, Wen; Xu, Fei; Qu, Tao; Li, Li; Que, Huayong; Zhang, Guofan

    2015-07-01

    Iodothyronine deiodinase catalyzes the initiation and termination of thyroid hormones (THs) effects, and plays a central role in the regulation of thyroid hormone level in vertebrates. In non-chordate invertebrates, only one deiodinase has been identified in the scallop Chlamys farreri. Here, two deiodinases were cloned in the Pacific oyster Crassostrea gigas ( CgDx and CgDy). The characteristic in-frame TGA codons and selenocysteine insertion sequence elements in the oyster deiodinase cDNAs supported the activity of them. Furthermore, seven orthologs of deiodinases were found by a tblastn search in the mollusk Lottia gigantea and the annelid Capitella teleta. A phylogenetic analysis revealed that the deiodinase gene originated from an common ancestor and a clade-specific gene duplication occurred independently during the differentiation of the mollusk, annelid, and vertebrate lineages. The distinct spatiotemporal expression patterns implied functional divergence of the two deiodinases. The expression of CgDx and CgDy was influenced by L-thyroxine T4, and putative thyroid hormone responsive elements were found in their promoters, which suggested that the oyster deiodinases were feedback regulated by TH. Epinephrine stimulated the expression level of CgDx and CgDy, suggesting an interaction effect between different hormones. This study provides the first evidence for the existence of a conserved TH feedback regulation mechanism in mollusks, providing insights into TH evolution.

  9. Distribution of aliphatic compounds in bivalve mollusks from Galicia after the Prestige oil spill: spatial and temporal trends.

    PubMed

    Carro, N; Cobas, J; Maneiro, J

    2006-03-01

    The content and distribution of n-alkane (C8-C35) and isoprenoid (pristane and phytane) hydrocarbons were investigated in two species of bivalve mollusk, mussel (Mytilus galloprovincialis) and cockle (Cerastoderma edule), collected at different points of the Galicia littoral zone during the period from December 2002 to February 2003 (after the Prestige oil spill). Samples were analyzed by high-resolution gas chromatography equipped with a flame ionization detector. The highest levels were found in mussels and cockles coming from two estuarine bays, Rías de Arousa and Vigo. Hydrocarbons with carbon chain length > 30 were detected and determined in all samples. The abundance of these hydrocarbons in biota could be interpreted with regard to the feeding and living habits. Chemometric techniques have been employed to analyze data and determine the potential source of hydrocarbon contamination. Differences between mussels and cockles were observed in relation to aliphatic content. According to the data analysis, the main source of hydrocarbon contamination of investigated samples seems to be more related to the intense traffic of vessels in these estuarine bays than to the Prestige oil spill. PMID:16253223

  10. Activation of transcription and retrotransposition of a novel retroelement, Steamer, in neoplastic hemocytes of the mollusk Mya arenaria

    PubMed Central

    Arriagada, Gloria; Metzger, Michael J.; Muttray, Annette F.; Sherry, James; Reinisch, Carol; Street, Craig; Lipkin, W. Ian; Goff, Stephen P.

    2014-01-01

    Bivalve mollusks of the North Atlantic, most prominently the soft shell clam Mya arenaria, are afflicted with an epidemic transmissible disease of the circulatory system closely resembling leukemia. The disease is characterized by a dramatic expansion of blast-like cells in the hemolymph with high mitotic index. Examination of hemolymph of diseased clams revealed high levels of reverse transcriptase activity, the hallmark of retroviruses and retroelements. By deep sequencing of RNAs from hemolymph, we identified transcripts of a novel retroelement, here named Steamer. The DNA of the element is marked by long terminal repeats and encodes a single large protein with similarity to mammalian retroviral Gag-Pol proteins. Steamer mRNA levels were specifically elevated in diseased hemocytes, and high expression was correlated with disease status. DNA copy number per genome was present at enormously high levels in diseased hemocytes, indicative of extensive reverse transcription and retrotransposition. Steamer activation in M. arenaria is an example of a catastrophic induction of genetic instability that may initiate or advance the course of leukemia. PMID:25201971

  11. Spatial distribution of Biomphalaria mollusks at São Francisco River Basin, Minas Gerais, Brazil, using geostatistical procedures.

    PubMed

    Guimarães, Ricardo J P S; Freitas, Corina C; Dutra, Luciano V; Felgueiras, Carlos A; Moura, Ana C M; Amaral, Ronaldo S; Drummond, Sandra C; Scholte, Ronaldo G C; Oliveira, Guilherme; Carvalho, Omar S

    2009-03-01

    Geostatistics is used in this work to make inferences about the presence of the species of Biomphalaria (B. glabrata, B. tenagophila and/or B. straminea), intermediate hosts of Schistosoma mansoni, at the São Francisco River Basin, in Minas Gerais, Brazil. One of these geostatistical procedures, known as indicator kriging, allows the classification of categorical data, in areas where the data are not available, using a punctual sample set. The result is a map of species and risk area definition. More than a single map of the categorical attribute, the procedure also permits the association of uncertainties of the stochastic model, which can be used to qualify the inferences. In order to validate the estimated data of the risk map, a fieldwork in five municipalities was carried out. The obtained results showed that indicator kriging is a rather robust tool since it presented a very good agreement with the field findings. The obtained risk map can be thought as an auxiliary tool to formulate proper public health strategies, and to guide other fieldwork, considering the places with higher occurrence probability of the most important snail species. Also, the risk map will enable better resource distribution and adequate policies for the mollusk control. This methodology will be applied to other river basins to generate a predictive map for Biomphalaria species distribution for the entire state of Minas Gerais. PMID:19046937

  12. Cm-p5: an antifungal hydrophilic peptide derived from the coastal mollusk Cenchritis muricatus (Gastropoda: Littorinidae).

    PubMed

    López-Abarrategui, Carlos; McBeth, Christine; Mandal, Santi M; Sun, Zhenyu J; Heffron, Gregory; Alba-Menéndez, Annia; Migliolo, Ludovico; Reyes-Acosta, Osvaldo; García-Villarino, Mónica; Nolasco, Diego O; Falcão, Rosana; Cherobim, Mariana D; Dias, Simoni C; Brandt, Wolfgang; Wessjohann, Ludger; Starnbach, Michael; Franco, Octavio L; Otero-González, Anselmo J

    2015-08-01

    Antimicrobial peptides form part of the first line of defense against pathogens for many organisms. Current treatments for fungal infections are limited by drug toxicity and pathogen resistance. Cm-p5 (SRSELIVHQRLF), a peptide derived from the marine mollusk Cenchritis muricatus peptide Cm-p1, has a significantly increased fungistatic activity against pathogenic Candida albicans (minimal inhibitory concentration, 10 µg/ml; EC50, 1.146 µg/ml) while exhibiting low toxic effects against a cultured mammalian cell line. Cm-p5 as characterized by circular dichroism and nuclear magnetic resonance revealed an α-helical structure in membrane-mimetic conditions and a tendency to random coil folding in aqueous solutions. Additional studies modeling Cm-p5 binding to a phosphatidylserine bilayer in silico and isothermal titration calorimetry using lipid monophases demonstrated that Cm-p5 has a high affinity for the phospholipids of fungal membranes (phosphatidylserine and phosphatidylethanolamine), only moderate interactions with a mammalian membrane phospholipid, low interaction with ergosterol, and no interaction with chitin. Adhesion of Cm-p5 to living C. albicans cells was confirmed by fluorescence microscopy with FITC-labeled peptide. In a systemic candidiasis model in mice, intraperitoneal administration of Cm-p5 was unable to control the fungal kidney burden, although its low amphiphaticity could be modified to generate new derivatives with improved fungicidal activity and stability. PMID:25921828

  13. From Mollusks to Medicine: A Venomics Approach for the Discovery and Characterization of Therapeutics from Terebridae Peptide Toxins.

    PubMed

    Verdes, Aida; Anand, Prachi; Gorson, Juliette; Jannetti, Stephen; Kelly, Patrick; Leffler, Abba; Simpson, Danny; Ramrattan, Girish; Holford, Mandë

    2016-01-01

    Animal venoms comprise a diversity of peptide toxins that manipulate molecular targets such as ion channels and receptors, making venom peptides attractive candidates for the development of therapeutics to benefit human health. However, identifying bioactive venom peptides remains a significant challenge. In this review we describe our particular venomics strategy for the discovery, characterization, and optimization of Terebridae venom peptides, teretoxins. Our strategy reflects the scientific path from mollusks to medicine in an integrative sequential approach with the following steps: (1) delimitation of venomous Terebridae lineages through taxonomic and phylogenetic analyses; (2) identification and classification of putative teretoxins through omics methodologies, including genomics, transcriptomics, and proteomics; (3) chemical and recombinant synthesis of promising peptide toxins; (4) structural characterization through experimental and computational methods; (5) determination of teretoxin bioactivity and molecular function through biological assays and computational modeling; (6) optimization of peptide toxin affinity and selectivity to molecular target; and (7) development of strategies for effective delivery of venom peptide therapeutics. While our research focuses on terebrids, the venomics approach outlined here can be applied to the discovery and characterization of peptide toxins from any venomous taxa. PMID:27104567

  14. From Mollusks to Medicine: A Venomics Approach for the Discovery and Characterization of Therapeutics from Terebridae Peptide Toxins

    PubMed Central

    Verdes, Aida; Anand, Prachi; Gorson, Juliette; Jannetti, Stephen; Kelly, Patrick; Leffler, Abba; Simpson, Danny; Ramrattan, Girish; Holford, Mandë

    2016-01-01

    Animal venoms comprise a diversity of peptide toxins that manipulate molecular targets such as ion channels and receptors, making venom peptides attractive candidates for the development of therapeutics to benefit human health. However, identifying bioactive venom peptides remains a significant challenge. In this review we describe our particular venomics strategy for the discovery, characterization, and optimization of Terebridae venom peptides, teretoxins. Our strategy reflects the scientific path from mollusks to medicine in an integrative sequential approach with the following steps: (1) delimitation of venomous Terebridae lineages through taxonomic and phylogenetic analyses; (2) identification and classification of putative teretoxins through omics methodologies, including genomics, transcriptomics, and proteomics; (3) chemical and recombinant synthesis of promising peptide toxins; (4) structural characterization through experimental and computational methods; (5) determination of teretoxin bioactivity and molecular function through biological assays and computational modeling; (6) optimization of peptide toxin affinity and selectivity to molecular target; and (7) development of strategies for effective delivery of venom peptide therapeutics. While our research focuses on terebrids, the venomics approach outlined here can be applied to the discovery and characterization of peptide toxins from any venomous taxa. PMID:27104567

  15. A continuous multi-millennial record of surficial bivalve mollusk shells from the São Paulo Bight, Brazilian shelf

    NASA Astrophysics Data System (ADS)

    Dexter, Troy A.; Kaufman, Darrell S.; Krause, Richard A.; Barbour Wood, Susan L.; Simões, Marcello G.; Huntley, John Warren; Yanes, Yurena; Romanek, Christopher S.; Kowalewski, Michał

    2014-03-01

    To evaluate the potential of using surficial shell accumulations for paleoenvironmental studies, an extensive time series of individually dated specimens of the marine infaunal bivalve mollusk Semele casali was assembled using amino acid racemization (AAR) ratios (n = 270) calibrated against radiocarbon ages (n = 32). The shells were collected from surface sediments at multiple sites across a sediment-starved shelf in the shallow sub-tropical São Paulo Bight (São Paulo State, Brazil). The resulting 14C-calibrated AAR time series, one of the largest AAR datasets compiled to date, ranges from modern to 10,307 cal yr BP, is right skewed, and represents a remarkably complete time series: the completeness of the Holocene record is 66% at 250-yr binning resolution and 81% at 500-yr binning resolution. Extensive time-averaging is observed for all sites across the sampled bathymetric range indicating long water depth-invariant survival of carbonate shells at the sediment surface with low net sedimentation rates. Benthic organisms collected from active depositional surfaces can provide multi-millennial time series of biomineral records and serve as a source of geochemical proxy data for reconstructing environmental and climatic trends throughout the Holocene at centennial resolution. Surface sediments can contain time-rich shell accumulations that record the entire Holocene, not just the present.

  16. Radiocarbon content of pre-bomb marine mollusks and variations in the 14C Reservoir age for coastal areas of the Barents and Kara Seas, Russia

    NASA Astrophysics Data System (ADS)

    Forman, Steven L.; Polyak, Leonid

    Fourteen mollusks, collected alive between 1900 and 1945 from the Russian Barents and Kara seas, were analyzed by AMS 14C dating to evaluate variations in the 14C marine reservoir for arctic coastal sites, which is important for correcting ages in paleoenvironmental time-series and advancing understanding of the exchange of carbon. The 14C ages on the mollusks reveal a range of marine reservoir values (R(t)) from 159 14C yr to 764 14C yr. The oldest R(t) values of 764 to 620 14C yr are for the bivalve Portlandia arctica, which often inhabit cold and low salinity waters and muddy substrates. The depleted 14C content for this bivalve reflects possibly the incorporation of old carbon from freshwater inputs and/or the consumption of old organic matter from the underlying sediments and pore waters. Other mollusks with sessile habitats and pelagic food sources gave significantly lower R(t) values between 159 and 344 14C yr. The youngest R(t) values indicate enrichment in 14C and may partially reflect enhanced transfer of 14C-enriched CO2 from the atmosphere to the ocean surface with wind-generated wave agitation. This study underscores that a variety of processes can lead to variable 14C depletion and enrichment of surface waters yielding a ca. 600 year age span for contemporaneous arctic mollusks. There may be added uncertainty in the 14C reservoir correction for deposit-feeder species such as Portlandia sp. and perhaps for certain benthic foraminifera (e.g. Nonion labradoricum) because these taxa often incorporate old organic matter from the substrate. A reservoir correction of ≥700 years may be more appropriate for infaunal, deposit-eater species, particularly in glacier-dominated environments. Mollusks and foraminifera with sessile habits and pelagic food sources should be selected preferentially for 14C dating, because their shells may more closely reflect the 14C content of the global-ocean mixed layer.

  17. Fractionation of a Basal Magma Ocean

    NASA Astrophysics Data System (ADS)

    Laneuville, M.; Hernlund, J. W.; Labrosse, S.

    2014-12-01

    Earth's magnetic field is thought to be sustained by dynamo action in a convecting metallic outer core since at least 3.45 Ga (Tarduno et al., 2010). Convection induces an isentropic temperature gradient that drains 13±3 TW of heat from the core by thermal conduction (de Koker et al., 2012; Pozzo et al., 2012; Gomi et al., 2013), and suggests that Earth's core has cooled by ˜1,000 K or more since Earth's formation (Gomi et al., 2013). However, models of Earth's initial thermal evolution following a giant-impact predict rapid cooling to the mantle melting temperature (e.g., Solomatov, 2007). In order to understand how the core could have retained enough heat to explain the age of the geodynamo, we relax a key assumption of the basal magma ocean model of (Labrosse et al., 2007) to allow for the possibility that the magma is stably stratified. Recent giant impact simulations suggest extensive core-mantle mixing (Saitoh and Makino, 2013), which could have produced such a large stratified magma layer at the core-mantle boundary. In the presence of a stable density gradient, heat transfer through the basal magma ocean occurs through conduction and therefore delays heat loss from the core. Partitioning of iron in the liquid phase upon crystallization changes the density profile and triggers convection in the upper part of the basal magma ocean. Our hypothesis suggests that early core cooling is dominated by the diffusion timescale through the basal magma ocean, and predicts a delayed onset of the geodynamo (i.e, during the late Headean/early Archean). This model can therefore be falsified if the existence of a geomagnetic field can be inferred from magnetization of inclusions in Hadean zircons. N. de Koker et al., Proc. Natl. Acad. Sci. 190, 4070-4073 (2012).H. Gomi et al., Phys. Earth Planet. Inter. 224, 88-103 (2013).S. Labrosse et al., Nature 450, 866-869 (2007).M. Pozzo et al., Nature 485, 355-358 (2012).T. Saitoh and J. Makino. Astrophys. J. 768, 44 (2013).V

  18. Mössbauer spectroscopy of Basal Ganglia

    SciTech Connect

    Miglierini, Marcel; Lančok, Adriana; Kopáni, Martin; Boča, Roman

    2014-10-27

    Chemical states, structural arrangement, and magnetic features of iron deposits in biological tissue of Basal Ganglia are characterized. The methods of SQUID magnetometry and electron microscopy are employed. {sup 57}Fe Mössbauer spectroscopy is used as a principal method of investigation. Though electron microscopy has unveiled robust crystals (1-3 μm in size) of iron oxides, they are not manifested in the corresponding {sup 57}Fe Mössbauer spectra. The latter were acquired at 300 K and 4.2 K and resemble ferritin-like behavior.

  19. Basal Cell Carcinoma. Part 1: Basal Cell Carcinoma Has Come of Age.

    PubMed

    Deng, Min; Marsch, Amanda F; Petronic-Rosic, Vesna

    2015-01-01

    Almost 2 centuries after its recognition, basal cell carcinoma (BCC) remains the most common cancer worldwide, with a 30% overall lifetime risk in the United States and an incidence that continues to increase annually. The increasing incidence of BCC is multifactorial and likely correlates to multiple risk factors, including exposure to both ionizing and UV radiation. Despite its relatively indolent growth, what was once referred to as a rodent ulcer or basal cell epithelioma is now identified as a full-fledged malignancy. The authors describe the societal burden of this disease and characterize its malignant potential, emphasizing associated clinical and histopathologic prognostic features. PMID:26380507

  20. Basal body replication and cilogenesis in a suctorian, Tokophrya infusionum.

    PubMed

    Millecchia, L L; Rudzinska, M A

    1970-09-01

    Basal body replication and ciliogenesis in Tokophrya infusionum were studied in synchronized cultures. Basal body replication occurs during the 1st hr of reproduction, which in Tokophrya is by internal budding. The number of basal bodies increases from about 20 to over 300 within this period. New basal bodies develop in association with mature basal bodies; they are formed at right angles to the mature basal body as short "probasal" bodies, which elongate, slant upward, become parallel to the mature basal body, and elongate to the mature size. Ciliogenesis occurs only during reproduction; the nonreproducing adult is not ciliated, and has only 18-25 barren basal bodies. Cilia first appear as short bulges above the basal body. The axonemal structure is incomplete at first, with one or both central microtubules absent, and occasionally the B fibers of the outer doublets are missing. Several accessory fibers are associated with the basal bodies, both in the adult and during reproduction. One of the fibers appears only after the cilia have sprouted. The scheme of basal body replication and ciliogenesis in Tokophrya is compared to that reported in other organisms, and the role of the accessory fibers is discussed. PMID:4349131

  1. High porosity of basal till at Burroughs glacier, southeastern Alaska

    SciTech Connect

    Ronnert, L.; Mickelson, D.M. )

    1992-09-01

    Debris-rich basal ice at Burroughs glacier, southeastern Alaska, has 60 vol% to 70 vol% debris. Recently deposited basal till exceeds 60 vol% sediment with 30% to almost 40% porosity. Where basal ice is very rich in debris, basal till is deposited through melt out with only slight compaction of the debris. Porosity this high in till is commonly associated with subglacially deforming and dilated sediment. However, the recently deposited basal melt-out till at Burroughs glacier has not been deformed after deposition, but has porosity values similar to tills elsewhere interpreted to be subglacially deforming and dilated in an unfrozen state. High porosity can occur in basal melt-out till deposited directly by basal melt out.

  2. Evolution of sensory structures in basal metazoa.

    PubMed

    Jacobs, Dave K; Nakanishi, Nagayasu; Yuan, David; Camara, Anthony; Nichols, Scott A; Hartenstein, Volker

    2007-11-01

    Cnidaria have traditionally been viewed as the most basal animals with complex, organ-like multicellular structures dedicated to sensory perception. However, sponges also have a surprising range of the genes required for sensory and neural functions in Bilateria. Here, we: (1) discuss "sense organ" regulatory genes, including; sine oculis, Brain 3, and eyes absent, that are expressed in cnidarian sense organs; (2) assess the sensory features of the planula, polyp, and medusa life-history stages of Cnidaria; and (3) discuss physiological and molecular data that suggest sensory and "neural" processes in sponges. We then develop arguments explaining the shared aspects of developmental regulation across sense organs and between sense organs and other structures. We focus on explanations involving divergent evolution from a common ancestral condition. In Bilateria, distinct sense-organ types share components of developmental-gene regulation. These regulators are also present in basal metazoans, suggesting evolution of multiple bilaterian organs from fewer antecedent sensory structures in a metazoan ancestor. More broadly, we hypothesize that developmental genetic similarities between sense organs and appendages may reflect descent from closely associated structures, or a composite organ, in the common ancestor of Cnidaria and Bilateria, and we argue that such similarities between bilaterian sense organs and kidneys may derive from a multifunctional aggregations of choanocyte-like cells in a metazoan ancestor. We hope these speculative arguments presented here will stimulate further discussion of these and related questions. PMID:21669752

  3. Phylogenetic differences of mammalian basal metabolic rate are not explained by mitochondrial basal proton leak

    PubMed Central

    Polymeropoulos, E. T.; Heldmaier, G.; Frappell, P. B.; McAllan, B. M.; Withers, K. W.; Klingenspor, M.; White, C. R.; Jastroch, M.

    2012-01-01

    Metabolic rates of mammals presumably increased during the evolution of endothermy, but molecular and cellular mechanisms underlying basal metabolic rate (BMR) are still not understood. It has been established that mitochondrial basal proton leak contributes significantly to BMR. Comparative studies among a diversity of eutherian mammals showed that BMR correlates with body mass and proton leak. Here, we studied BMR and mitochondrial basal proton leak in liver of various marsupial species. Surprisingly, we found that the mitochondrial proton leak was greater in marsupials than in eutherians, although marsupials have lower BMRs. To verify our finding, we kept similar-sized individuals of a marsupial opossum (Monodelphis domestica) and a eutherian rodent (Mesocricetus auratus) species under identical conditions, and directly compared BMR and basal proton leak. We confirmed an approximately 40 per cent lower mass specific BMR in the opossum although its proton leak was significantly higher (approx. 60%). We demonstrate that the increase in BMR during eutherian evolution is not based on a general increase in the mitochondrial proton leak, although there is a similar allometric relationship of proton leak and BMR within mammalian groups. The difference in proton leak between endothermic groups may assist in elucidating distinct metabolic and habitat requirements that have evolved during mammalian divergence. PMID:21632624

  4. Uranium-series dating of mollusks and corals, and age of Pleistocene deposits, Chesapeake Bay area, Virginia and Maryland

    USGS Publications Warehouse

    Mixon, Robert B.; Szabo, B. J.; Owens, James Patrick

    1982-01-01

    Geologic mapping in conjunction with uranium-series dating of fossil mollusks and corals suggests that the low-lying ( < 17 m in altitude) terrace deposits in the central and southern Chesapeake Bay area include two main depositional sequences, each of which represents a high stand of the sea in late Pleistocene time. The older depositional sequence includes the Accomack and Omar beds of the Delmarva area, the fossiliferous deposits along the lower Rappahannock River, and the Norfolk Formation deposits west of the Suffolk scarp. These beds have yielded a single reliable coral age estimate of 184,000?20,000 years B.P., suggesting an early late Pleistocene age. The younger sequence, including the type beds of the Norfolk Formation and equivalent strata east of the Suffolk scarp, has yielded several coral ages ranging from about 62,000 to 86,000 years B.P. (including ages from our samples and previously reported age estimates); thus, it is clearly late Pleistocene in age. Groupings of ages obtained from our quahog analyses also suggest two transgressive sequences; however, the estimated quahog ages are consistently younger than ages based on coral samples from the same and equivalent stratigraphic units. Stratigraphic, paleoclimatic, and geomorphic data suggest that the estimated uranium-series age of 71,000?7,000 years B.P. for the type beds of the Norfolk, obtained by averaging our coral dates, may be too young by as much as several tens of thousands of years. A postulated equivalency of the type Norfolk beds, upper Pleistocene deposits near Charleston, S.C. (apparent uranium-series age = 95,000?5,000 years), and deposits in the Caribbean area thought to represent the highest sea stand during the last interglacial period (apparent age, 125,000?10,000 years) implies diagenetic modification of coralline material possibly in part because of regional differences in depositional and postdepositional environments.

  5. Basal area from photos.... Is it possible?

    NASA Astrophysics Data System (ADS)

    Sparrow, B.; Ward, B.; Armston, J.; Schaefer, M.; Thurgate, N.; van den Hengel, A.; Lowe, A.; Phinn, S. R.

    2013-12-01

    This paper describes collaborative work conducted between the Ausplots and AusCover facilities within Australia's Terrestrial Ecosystem Research Network (TERN) and the Australian Centre for Visual Technologies (ACVT) to develop new photopoint collection methodologies for use by terrestrial ecologists. These photopoints are being collected at Ausplots survey sites throughout rangeland environments across Australia along with a wide suite of environmental measures, including a range of soil, vegetation species and structure and genetics information, with currently around 270 sites out of 700 collected. These collections are intended to augment the ecological data collected at each site and provide a record of that time. Similar measures are also being collected at Auscover calibration and validation sites. Our photopoints incorporate three sets of overlapping photographs, each collected from exposure points at the vertices of an equilateral triangle with sides of 2.5 m located around the centre point of the field site. The photos from each exposure point typically overlap by 50% and at least one photo in each series include a calibration target mounted on a pole at the centre of the exposure points. These photographs are then processed to create a range of data products. Seamless photo panoramas are constructed for each field site and are stored with the relevant site data allowing ecologists utilising the ecological data to also include the environment in which that data were collected. Point clouds are also produced allowing a three dimensional view of the site and potentially allowing similar analysis, albeit at lower precision, to that of terrestrial Lidar systems. These three dimensional site reconstructions are used to measure stem diameters, and calculate basal area, which are summed for the site, providing a measure of basal area per hectare when the visible distance is taken into account. This method is potentially more accurate than rapid techniques such as

  6. Radiation-induced basal cell carcinoma

    PubMed Central

    Zargari, Omid

    2015-01-01

    Background: The treatment of tinea capitis using radiotherapy was introduced at the beginning of the twentieth century. A variety of cancers including basal cell carcinoma (BCC) are seen years after this treatment. Objective: We sought to determine the clinical characteristics of BCCs among irradiated patients. Methods: The clinical records of all patients with BCC in a clinic in north of Iran were reviewed. Results: Of the 58 cases of BCC, 29 had positive history for radiotherapy in their childhood. Multiple BCCs were seen in 79.3% and 10.3% of patients with history and without history of radiotherapy, respectively. Conclusions: X-ray radiation is still a major etiologic factor in developing BCC in northern Iran. Patients with positive history for radiotherapy have higher rate of recurrence. PMID:26114066

  7. How to achieve a predictable basal insulin?

    PubMed

    Kurtzhals, P

    2005-09-01

    The development of insulin analogues over the last two decades have aimed at optimising the pharmacokinetic profile of subcutaneously injected insulin for therapeutic use in diabetes mellitus. Rapid acting analogues were successfully engineered and marketed in the late 1990's. In engineering long-acting analogues it has been a particular challenge to obtain action profiles that would be predictable from day to day in the same person. The most recent approach has been to acylate the insulin molecule with a fatty acid which provides the insulin molecule with a specific affinity for albumin. The first clinically available agent of this type is insulin detemir. Pharmacological studies have shown that reversible albumin binding will protract absorption following subcutaneous injection but still allow the insulin molecule to be recognised by the insulin receptor following dissociation from the carrier protein. Moreover, the molecular features of insulin detemir are attractive in that the molecule can be formulated as a neutral aqueous solution and does not precipitate after injection. Together with an important buffering mechanism effected by plasma albumin binding, this explains a highly significant reduction of within-subject variability of pharmacodynamic response observed in repeat isoglycaemic clamp studies where insulin detemir was compared to other basal insulin products. No safety considerations have been identified in using albumin as an insulin carrier to protract and buffer insulin action. In assessing the clinical attractiveness of insulin analogues, it is furthermore critically important to consider how the molecular modifications impact efficacy and safety. A number of pharmacological studies have shown that insulin detemir overall retains the molecular pharmacological properties of native human insulin, including a physiological balance between metabolic and mitogenic potencies. Taken together, insulin detemir provides an attractive novel approach for

  8. Concentrated insulins: the new basal insulins

    PubMed Central

    Lamos, Elizabeth M; Younk, Lisa M; Davis, Stephen N

    2016-01-01

    Introduction Insulin therapy plays a critical role in the treatment of type 1 and type 2 diabetes mellitus. However, there is still a need to find basal insulins with 24-hour coverage and reduced risk of hypoglycemia. Additionally, with increasing obesity and insulin resistance, the ability to provide clinically necessary high doses of insulin at low volume is also needed. Areas covered This review highlights the published reports of the pharmacokinetic (PK) and glucodynamic properties of concentrated insulins: Humulin-R U500, insulin degludec U200, and insulin glargine U300, describes the clinical efficacy, risk of hypoglycemic, and metabolic changes observed, and finally, discusses observations about the complexity of introducing a new generation of concentrated insulins to the therapeutic market. Conclusion Humulin-R U500 has a similar onset but longer duration of action compared with U100 regular insulin. Insulin glargine U300 has differential PK/pharmacodynamic effects when compared with insulin glargine U100. In noninferiority studies, glycemic control with degludec U200 and glargine U300 is similar to insulin glargine U100 and nocturnal hypoglycemia is reduced. Concentrated formulations appear to behave as separate molecular entities when compared with earlier U100 insulin analog compounds. In the review of available published data, newer concentrated basal insulins may offer an advantage in terms of reduced intraindividual variability as well as reducing the injection burden in individuals requiring high-dose and large volume insulin therapy. Understanding the PK and pharmacodynamic properties of this new generation of insulins is critical to safe dosing, dispensing, and administration. PMID:27022271

  9. Fast Modulation of Visual Perception by Basal Forebrain Cholinergic Neurons

    PubMed Central

    Estandian, Daniel; Xu, Min; Kwan, Alex C.; Lee, Seung-Hee; Harrison, Thomas C.; Feng, Guoping; Dan, Yang

    2014-01-01

    The basal forebrain provides the primary source of cholinergic input to the cortex, and it plays a crucial role in promoting wakefulness and arousal. However, whether rapid changes in basal forebrain neuron spiking in awake animals can dynamically influence sensory perception is unclear. Here we show that basal forebrain cholinergic neurons rapidly regulate cortical activity and visual perception in awake, behaving mice. Optogenetic activation of the cholinergic neurons or their V1 axon terminals improved performance of a visual discrimination task on a trial-by-trial basis. In V1, basal forebrain activation enhanced visual responses and desynchronized neuronal spiking, which could partly account for the behavioral improvement. Conversely, optogenetic basal forebrain inactivation decreased behavioral performance, synchronized cortical activity and impaired visual responses, indicating the importance of cholinergic activity in normal visual processing. These results underscore the causal role of basal forebrain cholinergic neurons in fast, bidirectional modulation of cortical processing and sensory perception. PMID:24162654

  10. Drosophila melanogaster as a model for basal body research.

    PubMed

    Jana, Swadhin Chandra; Bettencourt-Dias, Mónica; Durand, Bénédicte; Megraw, Timothy L

    2016-01-01

    The fruit fly, Drosophila melanogaster, is one of the most extensively studied organisms in biological research and has centrioles/basal bodies and cilia that can be modelled to investigate their functions in animals generally. Centrioles are nine-fold symmetrical microtubule-based cylindrical structures required to form centrosomes and also to nucleate the formation of cilia and flagella. When they function to template cilia, centrioles transition into basal bodies. The fruit fly has various types of basal bodies and cilia, which are needed for sensory neuron and sperm function. Genetics, cell biology and behaviour studies in the fruit fly have unveiled new basal body components and revealed different modes of assembly and functions of basal bodies that are conserved in many other organisms, including human, green algae and plasmodium. Here we describe the various basal bodies of Drosophila, what is known about their composition, structure and function. PMID:27382461

  11. Systematic detection of BMAA (β-N-methylamino-l-alanine) and DAB (2,4-diaminobutyric acid) in mollusks collected in shellfish production areas along the French coasts.

    PubMed

    Réveillon, Damien; Séchet, Véronique; Hess, Philipp; Amzil, Zouher

    2016-02-01

    The neurotoxin β-N-methylamino-l-alanine (BMAA) is naturally present in some microalgal species in the marine environment. The accumulation of BMAA has widely been observed in filter-feeding bivalves that are known to consume primary producers constituting the base of complex aquatic food webs. This study was performed to assess the occurrence of BMAA and isomers in mollusks collected from nine representative shellfish production areas located on the three French coasts (Channel, Atlantic and Mediterranean sites). The use of a highly selective and sensitive HILIC-MS/MS method, with D5DAB as internal standard, revealed the systematic detection of BMAA and DAB, in concentrations ranging from 0.20 to 6.7 μg g(-1) dry weight of digestive gland tissues of mollusks. While we detected BMAA in four strains of diatoms in a previous study, here BMAA was only detected in one diatom species previously not investigated out of the 23 microalgal species examined (belonging to seven classes). The concentrations of BMAA and DAB in mussels and oysters were similar at different sampling locations and despite the high diversity of phytoplankton populations that mollusks feed on at these locations. Only small variations of BMAA and DAB levels were observed and these were not correlated to any of the phytoplankton species reported. Therefore, extensive research should be performed on both origin and metabolism of BMAA in shellfish. The levels observed in this study are similar to those found in other studies in France or elsewhere. A previous study had related such levels to a cluster of Amyotrophic Lateral Sclerosis in the South of France; hence the widespread occurrence of BMAA in shellfish from all coasts in France found in this study suggests the need for further epidemiological and toxicological studies to establish the levels that are relevant for a link between the consumption of BMAA-containing foodstuffs and neurodegenerative diseases. PMID:26615827

  12. Late Neogene evolution of the East Asian monsoon revealed by terrestrial mollusk record in Western Chinese Loess Plateau: From winter to summer dominated sub-regime

    NASA Astrophysics Data System (ADS)

    Li, Fengjiang; Rousseau, Denis-Didier; Wu, Naiqin; Hao, Qingzhen; Pei, Yunpeng

    2008-10-01

    More and more evidence indicates that the onset of the East Asian (EA) monsoon can be traced back to the Oligocene-Miocene boundary (at about 23 Ma). However, the process of its evolution is still less well-known until now. Here we investigate its late Neogene evolution by analyzing a terrestrial mollusk sequence, from the Chinese Loess Plateau (CLP), covering the period between 7.1 and 3.5 Ma. Considering the modern ecological requirements of these organisms, we were able to define two groups of cold-aridiphilous (CA) and thermo-humidiphilous (TH) species, representing the EA winter and summer monsoon variations, respectively, as previously defined in the Quaternary glacial-interglacial cycles. Variations in these two groups indicate two different monsoon dominated periods during 7.1-3.5 Ma. First, between 7.1 and 5.5 Ma, the EA winter monsoon, with a 100-kyr periodicity, was dominant. Second, between 5.1 and 4 Ma, the EA summer monsoon dominated, with a 41-kyr periodicity. Furthermore, our mollusk record yields valuable evidence for a late Miocene-Pliocene transition of about 400 kyr from winter monsoon dominated towards summer monsoon dominated, associated with a periodicity transition from weak 100 kyr to 41 kyr. The strengthened winter monsoon interval, with a 100-kyr periodicity, is coeval with orbital-scale global ice-volume changes, in conjunction with the uplift of the Tibetan Plateau which probably reinforced the winter monsoon sub-regime. Conversely, closures of the Panama and Indonesian seaways, associated with changes in obliquity between 5.1 and 4 Ma, are probably major forcing factors for the observed dominant summer monsoon with 41-kyr frequency, favoring heat and moisture transports between low and high latitudes to allow TH mollusks to grow and develop in the CLP.

  13. An assemblage of mollusks associated with the high latitude scleractinian coral Alveopora japonica (Eguchi 1968) in Jeju Island, off the south coast of Korea

    NASA Astrophysics Data System (ADS)

    Noseworthy, Ronald G.; Hong, Hyun-Ki; Keshavmurthy, Shashank; Lee, Hee-Jung; Jeung, Hee-Do; Ju, Se-Jong; Kim, Jong-Bin; Jung, Sukgeun; Choi, Kwang-Sik

    2016-03-01

    Corals reefs and communities support a wide range of flora and fauna. The complete richness and abundance of faunal communities in either coral reefs or communities is not fully understood. This is especially true for high-latitude coral communities. In this work, we carried out an analysis of an Alveopora japonica associated mollusk assemblage, in Jeju Island, Korea. A. japonica is one of the major coral species present in high abundance (88-155 colonies m-2), with a high recruitment rate (7.8 juvenile corals m-2 yr-1) in Jeju Island, and may serve as a habitat for other benthic organisms. In 2012, a total number of 579 A. japonica colonies with sizes ranging between 15.1-346.7 cm2 in the surface area were collected from a 1m× 10m quadrat installed at a depth of 10 m at Keumneung, on the northwest coast of Jeju Island. Numerous benthic invertebrates were found to be associated with A. japonica colonies. Twenty-seven bivalves and gastropods were identified, including a boring mytilid, Lithophaga curta, and an arcid, Barbatia stearnsi. A zonalgeographical examination of the distribution ranges of these mollusks revealed a majority of warmer water species. Our observations also showed that A. japonica may be providing a habitat to grazing gastropod, Turbo cornutus, and encrusting Spondylidae and Chamidae bivalves. A. japonica forms a coral carpet with a distinct assemblage of bivalves. It is thought that the presence of these mollusks species in the coral indicates its use as a nursery for juvenile species, a ready food supply of organic detritus, and a refuge from predators.

  14. Site-specific basal body duplication in Chlamydomonas.

    PubMed

    O'Toole, Eileen T; Dutcher, Susan K

    2014-02-01

    Correct centriole/basal body positioning is required for numerous biological processes, yet how the cell establishes this positioning is poorly understood. Analysis of centriolar/basal body duplication provides a key to understanding basal body positioning and function. Chlamydomonas basal bodies contain structural features that enable specific triplet microtubules to be specified. Electron tomography of cultures enriched in mitotic cells allowed us to follow basal body duplication and identify a specific triplet at which duplication occurs. Probasal bodies elongate in prophase, assemble transitional fibers (TF) and are segregated with a mature basal body near the poles of the mitotic spindle. A ring of nine-singlet microtubules is initiated at metaphase, orthogonal to triplet eight. At telophase/cytokinesis, triplet microtubule blades assemble first at the distal end, rather than at the proximal cartwheel. The cartwheel undergoes significant changes in length during duplication, which provides further support for its scaffolding role. The uni1-1 mutant contains short basal bodies with reduced or absent TF and defective transition zones, suggesting that the UNI1 gene product is important for coordinated probasal body elongation and maturation. We suggest that this site-specific basal body duplication ensures the correct positioning of the basal body to generate landmarks for intracellular patterning in the next generation. PMID:24166861

  15. Mechanisms of platelet adhesion to the basal lamina.

    PubMed Central

    Huang, T. W.; Benditt, E. P.

    1978-01-01

    The human glomerular basal lamina (HGBL) is composed of collagenous and noncollagenous glycoproteins. We assessed the role played by each costituent in platelet-basal-lamina interaction by selective cleavage and removal of each component by clostridial collagenase or by pepsin. When noncollagenous proteins are removed from HGBL, human platelets exhibit littel reactivity toward the residual collagen framework of the isolated basal lamina. With the noncollagen matrix of basal lamina, after removal of the bulk of the collagen, platelet adhesion and spreading proceed normally in the presence of divalent cations, similar to what occurs on intact basal lamina. No platelet degranulation or aggregation is observed. The results indicate that the basal lamina collagen, even in its native packing arrangement, lacks affinity for platelet adhesion and is incapable of triggering platelet release reactions. Platelet adhesion and spreading on the basal lamina appears to depend primarily on the presence of the noncollagen components and to require divalent cations. The data suggest the presence on platelets of receptors for basal lamina distinct from those for interstitial collagens. These receptors activate a unique modulation of platelet behavior, ie, adhesion and spreading without degranulation. A difference in biologic function of the basal lamina and interstitial collagens is apparent in these experiments. Images Figure 4 Figure 5 Figure 6 Figure 1 Figure 2 Figure 3 PMID:210672

  16. Insulin Degludec, The New Generation Basal Insulin or Just another Basal Insulin?

    PubMed

    Nasrallah, Sami N; Reynolds, L Raymond

    2012-01-01

    The advances in recombinant DNA technology have led to an improvement in the properties of currently available long-acting insulin analogs. Insulin degludec, a new generation ultra-long-acting basal insulin, currently in phase 3 clinical trials, has a promising future in clinical use. When compared to its rival basal insulin analogs, a longer duration of action and lower incidence of hypoglycemic events in both type 1 and type 2 diabetic patients has been demonstrated.1,2 Its unique mechanism of action is based on multihexamer formation after subcutaneous injection. This reportedly allows for less pharmacodynamic variability and within-subject variability than currently available insulin analogs, and a duration of action that is over 24 hours.3 The lack of proof of carcinogenicity with insulin degludec is yet another factor that would be taken into consideration when choosing the optimal basal insulin for a diabetic individual.4 A formulation of insulin degludec with insulin aspart, Insulin degludec 70%/aspart 30%, may permit improved flexibly of dosing without compromising glycemic control or safety.5. PMID:22879797

  17. Distinctive Patterns of CTNNB1 (β-Catenin) Alterations in Salivary Gland Basal Cell Adenoma and Basal Cell Adenocarcinoma.

    PubMed

    Jo, Vickie Y; Sholl, Lynette M; Krane, Jeffrey F

    2016-08-01

    Salivary gland basaloid neoplasms are diagnostically challenging. Limited publications report that some basal cell adenomas harbor CTNNB1 mutations, and nuclear β-catenin expression is prevalent. We evaluated β-catenin expression in basal cell adenomas and adenocarcinomas in comparison with salivary tumors in the differential diagnosis and performed targeted genetic analysis on a subset of cases. β-catenin immunohistochemistry was performed on formalin-fixed, paraffin-embedded whole sections from 73 tumors. Nuclear staining was scored semiquantitatively by extent and intensity. DNA was extracted from 6 formalin-fixed, paraffin-embedded samples (5 basal cell adenomas, 1 basal cell adenocarcinoma) for next-generation sequencing. Nuclear β-catenin staining was present in 18/22 (82%) basal cell adenomas; most were diffuse and strong and predominant in the basal component. Two of 3 basal cell adenocarcinomas were positive (1 moderate focal; 1 moderate multifocal). All adenoid cystic carcinomas (0/20) and pleomorphic adenomas (0/20) were negative; 2/8 epithelial-myoepithelial carcinomas showed focal nuclear staining. Most β-catenin-negative tumors showed diffuse membranous staining in the absence of nuclear staining. Four of 5 basal cell adenomas had exon 3 CTNNB1 mutations, all c.104T>C (p.I35T). Basal cell adenocarcinoma showed a more complex genomic profile, with activating mutations in PIK3CA, biallelic inactivation of NFKBIA, focal CYLD deletion, and without CTNNB1 mutation despite focal β-catenin expression. Nuclear β-catenin expression has moderate sensitivity (82%) for basal cell adenoma but high specificity (96%) in comparison with its morphologic mimics. CTNNB1 mutation was confirmed in most basal cell adenomas tested, and findings in basal cell adenocarcinoma suggest possible tumorigenic mechanisms, including alterations in PI3K and NF-κB pathways and transcriptional regulation. PMID:27259009

  18. Heterogeneity of basal keratinocytes: nonrandom distribution of thymidine-labeled basal cells in confluent cultures is not a technical artifact

    SciTech Connect

    Milstone, L.M.; LaVigne, J.F.

    1985-06-01

    Basal surface autoradiography of (/sup 3/H)dThd-labeled, confluent, keratinocyte cultures reveals that proliferating cells have a nonrandom, patterned distribution. Unlabeled cells, likewise, appear nonrandomly in clusters. The authors show here that failure to detect DNA synthesis in some basal cells in culture is not an artifact caused either by physical separation of the labeled nuclei from the radiographic emulsion or by a diffusion barrier that would prevent (/sup 3/H)dThd from reaching basal cells.

  19. Nevoid basal cell carcinoma syndrome (Gorlin syndrome)

    PubMed Central

    Lo Muzio, Lorenzo

    2008-01-01

    Nevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin syndrome, is a hereditary condition characterized by a wide range of developmental abnormalities and a predisposition to neoplasms. The estimated prevalence varies from 1/57,000 to 1/256,000, with a male-to-female ratio of 1:1. Main clinical manifestations include multiple basal cell carcinomas (BCCs), odontogenic keratocysts of the jaws, hyperkeratosis of palms and soles, skeletal abnormalities, intracranial ectopic calcifications, and facial dysmorphism (macrocephaly, cleft lip/palate and severe eye anomalies). Intellectual deficit is present in up to 5% of cases. BCCs (varying clinically from flesh-colored papules to ulcerating plaques and in diameter from 1 to 10 mm) are most commonly located on the face, back and chest. The number of BBCs varies from a few to several thousand. Recurrent jaw cysts occur in 90% of patients. Skeletal abnormalities (affecting the shape of the ribs, vertebral column bones, and the skull) are frequent. Ocular, genitourinary and cardiovascular disorders may occur. About 5–10% of NBCCS patients develop the brain malignancy medulloblastoma, which may be a potential cause of early death. NBCCS is caused by mutations in the PTCH1 gene and is transmitted as an autosomal dominant trait with complete penetrance and variable expressivity. Clinical diagnosis relies on specific criteria. Gene mutation analysis confirms the diagnosis. Genetic counseling is mandatory. Antenatal diagnosis is feasible by means of ultrasound scans and analysis of DNA extracted from fetal cells (obtained by amniocentesis or chorionic villus sampling). Main differential diagnoses include Bazex syndrome, trichoepithelioma papulosum multiplex and Torre's syndrome (Muir-Torre's syndrome). Management requires a multidisciplinary approach. Keratocysts are treated by surgical removal. Surgery for BBCs is indicated when the number of lesions is limited; other treatments include laser ablation, photodynamic

  20. Constraining riverine δ13C-DIC using Late Cretaceous and Early Paleogene freshwater bivalve mollusks (Unionoidea) form Montana

    NASA Astrophysics Data System (ADS)

    Gillikin, D. P.; Goodwin, D. H.; Davidson, M.; Hartman, J.

    2014-12-01

    Interpretation of carbon isotope variation in freshwater unionoid mollusk shells (δ13CSHELL) is not straightforward because of the variable contributions of metabolic (i.e., food) and dissolved inorganic carbon (DIC). Bivalve shells typically contain between 0 and 50% metabolic carbon (CM), which has a δ13C value close to the animal's food source. In marine systems, the food source (usually phytoplankton) has a δ13C value typically around -20 ‰ and a d13CDIC value around ~0 ‰. In freshwater systems, these numbers can vary considerably, with food sources ranging from -35 to -10 ‰. Typically, δ13C-DIC values range between -25 to 0‰ and are dependent on numerous factors; carbonate weathering and equilibrium with the atmosphere typically leading to high values and respiration of organic matter and oxidation of methane leading to lower values. Therefore, δ13C-DIC values reflect numerous processes occurring in the watershed. Nevertheless, here we suggest δ13CSHELL values can constrain the lower bounds of riverine δ13C-DIC values, despite the influence of CM. The metabolic end-member δ13C value is typically lower than the DIC end member and consequently will lead to higher calculated δ13C-DIC when using δ13CSHELL values. Therefore, if the CM fraction is set to 0 %, δ13CSHELL values will provide the lowest possible riverine δ13C-DIC values (after accounting for fractionation). Applying this method to modern shells from waters with known δ13C-DIC values (ranging from -3.2 to -12.8 ‰) results in calculated δ13C-DIC values from -6.0 to -12.4 ‰, which is close to measured DIC data from the waters in which the mussel grew. This can then in turn be applied to well-preserved fossil shells. Freshwater unionoid shells from the uppermost Cretaceous Hell Creek Formation and the lower Paleogene Fort Union Formation are exceptionally well preserved. Applying this method to these shells results in δ13C-DIC values ranging from -6 to -11‰, which is consistent

  1. New basal cell carcinoma susceptibility loci

    PubMed Central

    Stacey, Simon N.; Helgason, Hannes; Gudjonsson, Sigurjon A.; Thorleifsson, Gudmar; Zink, Florian; Sigurdsson, Asgeir; Kehr, Birte; Gudmundsson, Julius; Sulem, Patrick; Sigurgeirsson, Bardur; Benediktsdottir, Kristrun R.; Thorisdottir, Kristin; Ragnarsson, Rafn; Fuentelsaz, Victoria; Corredera, Cristina; Gilaberte, Yolanda; Grasa, Matilde; Planelles, Dolores; Sanmartin, Onofre; Rudnai, Peter; Gurzau, Eugene; Koppova, Kvetoslava; Nexø, Bjørn A.; Tjønneland, Anne; Overvad, Kim; Jonasson, Jon G.; Tryggvadottir, Laufey; Johannsdottir, Hrefna; Kristinsdottir, Anna M.; Stefansson, Hreinn; Masson, Gisli; Magnusson, Olafur T.; Halldorsson, Bjarni V.; Kong, Augustine; Rafnar, Thorunn; Thorsteinsdottir, Unnur; Vogel, Ulla; Kumar, Rajiv; Nagore, Eduardo; Mayordomo, José I.; Gudbjartsson, Daniel F.; Olafsson, Jon H.; Stefansson, Kari

    2015-01-01

    In an ongoing screen for DNA sequence variants that confer risk of cutaneous basal cell carcinoma (BCC), we conduct a genome-wide association study (GWAS) of 24,988,228 SNPs and small indels detected through whole-genome sequencing of 2,636 Icelanders and imputed into 4,572 BCC patients and 266,358 controls. Here we show the discovery of four new BCC susceptibility loci: 2p24 MYCN (rs57244888[C], OR=0.76, P=4.7 × 10−12), 2q33 CASP8-ALS2CR12 (rs13014235[C], OR=1.15, P=1.5 × 10−9), 8q21 ZFHX4 (rs28727938[G], OR=0.70, P=3.5 × 10−12) and 10p14 GATA3 (rs73635312[A], OR=0.74, P=2.4 × 10−16). Fine mapping reveals that two variants correlated with rs73635312[A] occur in conserved binding sites for the GATA3 transcription factor. In addition, expression microarrays and RNA-seq show that rs13014235[C] and a related SNP rs700635[C] are associated with expression of CASP8 splice variants in which sequences from intron 8 are retained. PMID:25855136

  2. Basal activity of GIRK5 isoforms.

    PubMed

    Salvador, Carolina; Mora, Silvia I; Ordaz, Benito; Antaramian, Anaid; Vaca, Luis; Escobar, Laura I

    2003-02-14

    G protein-coupled inwardly rectifying K(+) channels (GIRK or Kir3) form functional heterotetramers gated by Gbetagamma subunits. GIRK channels are critical for functions as diverse as heart rate modulation and neuronal post-synaptic inhibition. GIRK5 (Kir3.5) is the oocyte homologue of the mammalian GIRK subunits that conform the K(ACh) channel. It has been claimed that even when the oocytes express GIRK5 proteins they do not form functional channels. However, the GIRK5 gene shows three initiation sites that suggest the existence of three isoforms. In a previous work we demonstrated the functionality of homomultimers of the shortest isoform overexpressed in the own oocytes. Remarkably, the basal GIRK5-Delta25 inward currents were not coupled to the activation of a G-protein receptor in the oocytes. These results encouraged us to study this channel in another expression system. In this work we show that Sf21 insect cells can be successfully transfected with this channel. GIRK5-Delta25 homomultimers produce time-dependent inward currents only with GTPgammaS in the recording pipette. Therefore, alternative modes of stimulus input to heterotrimeric G-proteins should be present in the oocytes to account for these results. PMID:12535718

  3. A basal carbon concentrating mechanism in plants?

    PubMed

    Zabaleta, Eduardo; Martin, M Victoria; Braun, Hans-Peter

    2012-05-01

    Many photosynthetic organisms have developed inorganic carbon (Ci) concentrating mechanisms (CCMs) that increase the CO₂ concentration within the vicinity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO). Several CCMs, such as four carbon (C4) and crassulacean acid metabolism (CAM), bicarbonate accumulation systems and capsular structures around RubisCO have been described in great detail. These systems are believed to have evolved several times as mechanisms that acclimate organisms to unfavourable growth conditions. Based on recent experimental evidence we propose the occurrence of another more general CCM system present in all plants. This basal CCM (bCCM) is supposed to be composed of mitochondrial carbonic anhydrases (a β-type carbonic anhydrase and the γ-type carbonic anhydrase domain of the mitochondrial NADH dehydrogenase complex) and probably further unknown components. The bCCM is proposed to reduce leakage of CO₂ from plant cells and allow efficient recycling of mitochondrial CO₂ for carbon fixation in chloroplasts. PMID:22404837

  4. Fluctuating selection on basal metabolic rate.

    PubMed

    Nilsson, Johan F; Nilsson, Jan-Åke

    2016-02-01

    BMR (Basal metabolic rate) is an important trait in animal life history as it represents a significant part of animal energy budgets. BMR has also been shown to be positively related to sustainable work rate and maximal thermoregulatory capacity. To this date, most of the studies have focused on the causes of interspecific and intraspecific variation in BMR, and fairly little is known about the fitness consequences of different metabolic strategies. In this study, we show that winter BMR affects local survival in a population of wild blue tits (Cyanistes caeruleus), but that the selection direction differs between years. We argue that this fluctuating selection is probably a consequence of varying winter climate with a positive relation between survival and BMR during cold and harsh conditions, but a negative relation during mild winters. This fluctuating selection can not only explain the pronounced variation in BMR in wild populations, but will also give us new insights into how energy turnover rates can shape the life-history strategies of animals. Furthermore, the study shows that the process of global warming may cause directional selection for a general reduction in BMR, affecting the general life-history strategy on the population level. PMID:26839687

  5. Anti-basal ganglia antibodies in PANDAS.

    PubMed

    Singer, Harvey S; Loiselle, Christopher R; Lee, Olivia; Minzer, Karen; Swedo, Susan; Grus, Franz H

    2004-04-01

    An autoimmune-mediated mechanism involving molecular mimicry has been proposed for a variety of pediatric movement disorders that occur after a streptococcal infection. In this study, anti-basal ganglia antibodies (ABGA) were measured in 15 children with the diagnosis of pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS) and compared with those in 15 controls. ELISA and Western immunoblotting (WB) methods were used to detect ABGA against supernatant (S1), pellet (P2), and synaptosomal preparations from adult postmortem caudate, putamen, and globus pallidus. ELISA optical density values did not differ between PANDAS patients and controls across all preparations. Immunoblotting identified multiple bands in all subjects with no differences in the number of bands or their total density. Discriminant analysis, used to assess mean binding patterns, showed that PANDAS patients differed from controls only for the caudate S1 fraction (Wilks' lambda = 0.0236, P < 0.0002), with PANDAS-primarily tic subjects providing the greatest discrimination. Among the epitopes contributing to differences between PANDAS and control in the caudate S1 fraction, mean binding to the epitope at 183 kDa was the most different between groups. In conclusion, ELISA measurements do not differentiate between PANDAS and controls, suggesting a lack of major antibody changes in this disorder. Further immunoblot analyses using a caudate supernatant fraction are required to completely exclude the possibility of minor antibody repertoire differences in PANDAS subjects, especially in those who primarily have tics. PMID:15077238

  6. The effective treatment of basal cell carcinoma.

    PubMed

    Skelton, Lucy Anne

    Basal cell carcinoma (BCC) accounts for 75% of all skin cancers and its incidence is rising by between 3-8% each year (Szeimies and Karrer, 2006). As a result, the development of new therapeutic strategies and treatment methods for the removal of BCC is crucial in combating what is a growing problem. Surgical techniques, such as Mohs micrographic surgery, cryotherapy/cryosurgery, curettage and carbon dioxide laser therapy, as well as non-surgical techniques, such as radiotherapy, are recognized as potential options. The aim of this article is to critically review some of the current literature in order to substantiate the efficacy of destructive and non-surgical techniques as reliable alternatives to surgery for the management/removal of BCCs. The success rate, cosmetic outcome, pain and discomfort, recurrence rates, and the cost associated with each method are explored and discussed. Results of the review indicate that no one treatment is completely superior. According to the research, simple excision and Mohs micrographic surgery provide the lowest recurrence rates. However, in relation to success rates, patients tolerance of the treatment and cosmetic outcomes, and depending on the type of BCC involved, other treatment methods do offer reliable alternatives. PMID:19329898

  7. What has happened to the benthic mollusks of the Yellow Sea in the near half century? Comparison on molluscan biodiversity between 1959 and 2007

    NASA Astrophysics Data System (ADS)

    Zhang, Junlong; Zhang, Suping; Zhang, Shuqian; Du, Yongfen; Xu, Fengshan

    2016-02-01

    In recent years, the ecological environment in the Yellow Sea has changed greatly, as it has been influenced by climate change and various human activities. In this study, molluscan biodiversity at 42 sampling sites sampled in July 1959 and June 2007 were compared. The result showed that biomass of mollusks changed slight (p=0.981; 4.92 g/m2vs 4.88 g/m2), while abundances were higher in 2007 (p=0.038<0.05; 81.79 ind/m2vs 45.10 ind/m2), and the number of species (p=0.021<0.05), Margalef's species richness (p=0.005<0.01), and Shannon-Wiener index (p=0.006<0.01) was higher in 1959. The sites in the Yellow Sea Cold Water Mass occupied area, which were dominated by cold water species, were clustered together by the agglomerative classification method and the community there was rather stable, whilst great changes have occurred for the communities sited in the coastal waters. It is indicated that molluscan communities of the Yellow Sea were in undisturbed condition in 1959 (W= 0.051), but were severely impacted in 2007 (W= -0.058) resulting from the abundance/biomass comparison (ABC) method. Though the abundance increased, the biodiversity decreased and the community structure changed greatly. Generally, temperature, water depth, and salinity were major factors that affected the distribution of mollusks in the Yellow Sea.

  8. [Abundance and richness of mollusks and crustaceans associated to the submerged roots of red mangrove (Rhizophora mangle) at Bocaripo Lagoon, Sucre, Venezuela].

    PubMed

    Cedeño, Jennellis; Jiménez Prieto, Mayré; Pereda, Luisana; Allen, Thays

    2010-10-01

    Mangrove roots are important habitats for many species. The abundance and richness of mollusks and crustaceans associated with the roots demerged of Rhizophora mangle was studied. The samples were gathered between February 2005 and January 2006, in Bocaripo lagoon, north coast of Sucre state, Venezuela. Five stations were established inside the lagoon; on every station two roots were chosen at random, put in plastic bags and scraped. The associated organisms were separated by taxa and fixed in 10% formaldehyde. One thousand ninety two specimens of mollusks, distributed in two classes: Bivalve and Gastropod were collected. Bivalve was the most abundant with 943 individuals. The most representative family was Mytilidae with 6 species, being Musculus lateralis the dominant species. The crustaceans were represented by 372 organisms, belonging to the class Malacostraca, where Panopeus herbstii (169 ind.) was the most abundant species. The families Panopeidae, Porcellanidae and Majidae had the highest number of species. Maximum abundance was in February (224 ind.), with a richness of 25 species and the minimums in November (45 ind.) and a richness of 12 species. The stations 1 and 5 presented the major abundance and richness of organisms, which could be related to environmental conditions favorable, as the major availability of microhabitats and nourishing offer; on the contrary the station 4, presented a more inhospitable environment, due to the high values in the salinity and temperature, which contributes with the minor abundance and richness of the present species. PMID:21302531

  9. AMS-dated mollusks in beach ridges and berms document Holocene sea-level and coastal changes in northeastern Kuwait Bay

    NASA Astrophysics Data System (ADS)

    Reinink-Smith, Linda M.

    2015-09-01

    In northeastern Kuwait, ancient beach ridges and associated berms are separated from the present shoreline by a 4-6 km-wide sabkha. A diverse mollusk fauna in the beach ridges attests to a former open marine environment. A total of 21 AMS dates were obtained in this study. Thirteen mollusk samples from beach ridges yielded AMS dates ranging from ~ 6990 cal yr BP in the southeast to ~ 3370 cal yr BP in the northwest, suggesting a southeast to northwest age progression during the Holocene transgression. In contrast, four samples from berms throughout the study area yielded AMS dates of 5195-3350 cal yr BP showing no age progression; these berms consist largely of Conomurex persicus gastropods that aggregated by storms during a highstand at ~ 5000-3500 cal yr BP. The berms are presently at ~ + 6 m above sea level, 2-3 m above the beach ridges. Human settlements were common on the ridge crests before and after the highstand. Regression to present-day sea level commenced after the highstand, which is when the sabkha began forming. A landward, marine-built terrace, which yielded AMS dates > 43,500 14C yr BP, probably formed during Marine Oxygen Isotope Stage 5e and hence is not genetically related to the beach ridges.

  10. Removal of Cd2+ from contaminated water by nano-sized aragonite mollusk shell and the competition of coexisting metal ions.

    PubMed

    Du, Yang; Zhu, Lingyan; Shan, Guoqiang

    2012-02-01

    The potential of using nano-sized aragonite mollusk shell (nano-Bio-ARA) to remove Cd(2+) from contaminated water was investigated by comparing the sorption kinetics and isotherms with the nano-sized calcite-type mollusk shell (nano-Bio-CAL) and nano-sized geological calcite (nano-Geo-CAL). Nano-Bio-ARA displayed extremely high sorption capacity to Cd(2+) (8.91mmol/g), much higher than nano-Bio/Geo-CAL, and many other natural or engineered materials. The results of thermodynamic experiments indicated that the sorption of Cd(2+) on the nano-ARA was a spontaneous and endothermic process. The coexisting metals in the solution displayed competition effect to the sorption of Cd(2+) on nano-Bio-ARA in the following order: Cu(2+)>Cr(3+)>Pb(2+)>Zn(2+)>Ca(2+). EDTA impeded the sorption of Cd(2+) on nano-Bio-ARA due to its strong chelating capacity to Cd(2+) in the solution. The results demonstrate that nano-Bio-ARA is a potential high-effective material to treat Cd(2+) contaminated water. PMID:22047918

  11. Using watershed characteristics, sediment, and tissue of resident mollusks to identify potential sources of trace elements to streams in a complex agricultural landscape.

    PubMed

    Ciparis, Serena; Schreiber, Madeline E; Voshell, J Reese

    2012-05-01

    Trace elements used in animal feed additives can be introduced to aquatic environments through application of manures from animal feeding operations to agricultural land as fertilizer. The use of poultry feed additives containing arsenic (As) is of particular concern in the Shenandoah River watershed (Virginia, USA), an agricultural landscape with a high density of poultry operations. This study investigated the relationship between watershed characteristics of Shenandoah River tributaries and trace element concentrations in streambed sediment and tissue of resident mollusks, including: Asian clams (Corbicula fluminea), which are commonly used biomonitors, and pleurocerid snails (Leptoxis carinata), which are generally understudied. Results failed to support the primary hypothesis of a predictive relationship between watershed densities of poultry operations and As concentrations in sediment and mollusk tissue. However, there were statistical relationships between land use in tributary watersheds and other trace elements in sediment (Cu, Mn, Pb, Zn) and tissue (Cd, Hg, Pb). Principal components analysis of the sediment data suggested a possible geologic source of As at some sites. Tissue concentrations of As were significantly higher in snails than in clams, but clams accumulated higher concentrations of other trace elements (Cd, Cr, Hg, Pb, Se). Snails may be useful biomonitors of environmental As, but appear to be less suitable than clams for studies of landscape sources of other trace elements. PMID:21713480

  12. The Place of Career Women in the Basals.

    ERIC Educational Resources Information Center

    Leondis, Mary T.

    A study analyzed two basal reading series to determine if they depicted realistically the role of the career woman as she exists in society. A list of female careers in the 1989 editions of Houghton-Mifflin and McGraw Hill reading basals for grades 1 to 6 was compared to the career categories of the "United States Bureau of Census, Statistical…

  13. How Are Squamous and Basal Cell Skin Cancers Diagnosed?

    MedlinePlus

    ... often enough to cure basal and squamous cell skin cancers without further treatment. There are different types of skin biopsies. The ... and Prevention Early Detection, Diagnosis, and Staging Treating Skin Cancer - ... Your Doctor After Treatment What`s New in Skin Cancer - Basal and Squamous ...

  14. How are Senior Citizens Portrayed in Basal Readers?

    ERIC Educational Resources Information Center

    Rosen, Doris F.

    Five commonly used basal readers from grades one through three were studied to determine how they portrayed and represented older adults. It was hypothesized that older adults would be portrayed as active, contributing, and productive members of society and that they would be represented in the basals in proportion to their numbers in the…

  15. Mineralizing angiopathy with basal ganglia stroke in an infant

    PubMed Central

    Jain, Puneet; Kishore, Praveen; Bhasin, Jasjit Singh; Arya, Subhash Chand

    2015-01-01

    Basal ganglia stroke is known following trivial head trauma. Recently a distinct clinic-radiological entity termed ‘mineralizing angiopathy’ was described. We report an infant who developed basal ganglia stroke following trivial fall. His clinic-radiological features are described. PMID:26019426

  16. Paleozoic mollusk: Hyolithes

    USGS Publications Warehouse

    Marek, L.; Yochelson, E.L.

    1964-01-01

    An unusually well-preserved Ordovician fossil from Czechoslovakia shows that the enigmatic paired structures once thought to be outgrowths of the operculum of Hyolithes are really independent structures lying between the operculumn and the aperture of the shell. The find seems to provide conclusive proof of the morphologic uniqueness of hyolithids.

  17. Giant basal cell carcinoma of the forehead: a case report.

    PubMed

    Rudić, Milan; Kranjcec, Zoran; Lisica-Sikić, Natasa; Kovacić, Marijan

    2012-03-01

    Giant basal cell carcinoma (GBCC) is defined as a tumor 5cm or greater in diameter. They present less than 1% of all basal cell carcinomas. We present a case of an 85-year-old male patient with a giant ulcerating tumor of the left forehead (measuring 7x6 cm). Under local anesthesia tumor was surgically excised. No involvement of the underlying periostal or bone structure was noted. Pathohystological exam revealed the giant basal cell carcinoma, with free surgical margins. Giant basal cell carcinomas are rare tumors and are usually result of a long duration and patient neglect. In comparison to the ordinary basal cell carcinoma these tumors have a higher metastatic potential. Surgical resection with negative surgical margin is the best possible treatment option. PMID:22816239

  18. Relationships of Bexar shale, Hensel sandstone, and Hensel dolomite (basal upper Trinity, Comanchean Cretaceous) in south-central Texas

    SciTech Connect

    Amsbury, D.L.

    1984-04-01

    The Bexar Shale has been considered the offshore equivalent of the Cow Creek Limestone, the overlying Hensel sandstone, or of the disconformity between them in outcropping sections. Cores and outcrops in Comal, Kendall, and northern Bexar Counties preserve calcitic and dolomitic caliche in the top of the Cow Creek Limestone. Above the caliche is 8-16 m(25-50 ft) of laminated or bioturbated, dolomitic siltstone and silty dolomite (Hensel dolomite). Dolomite is euhedral and silt-sized. The lower part contains collophane grains and oyster shells replaced partly by chalcedony. Carbonate grains within the upper part include angular and well-rounded mollusk and echinoid fragments; many are pyritic and coated by glauconite. Terrigenous grains in Hensel dolomite grade upward from silt to coarse subarkose sand from central Texas. In southern Bexar County, about 35 m (115 ft) of silt-, clay-, and calcite-mudstone referable to the Bexar Shale sharply overlie shallow marine Cow Creek Limestone, and grade abruptly upward into about 7 m (23 ft) of Hensel dolomite. Dolomite is overlain by calcarenite of the Glen Rose Formation containing subarkose sand grains. Similar distinctive sand grains occur in well cuttings of basal Glen Rose beds northeastward through Travis County. The Bexar represents a flood of clay-sized sediment from a distant source, spread across the San Marcos arch during a rapid transgression. Slightly younger sand, silt, and local clay of the Hensel sandstone were eroded from central Texas by a few flash floods during a major period of caliche formation in the area.

  19. Basal slip and mechanical anisotropy of biotite

    SciTech Connect

    Kronenberg, A.K. ); Kirby, S.H.; Pinkston, J. )

    1990-11-10

    The basal slip systems of biotite and their mechanical expressions have been investigated by shortening single crystals oriented to maximize and minimize shear stresses on (001). Samples loaded at 45{degree} to (001) exhibit gentle external rotations associated with dislocation glide. Samples shortened perpendicular to (001) show no evidence of nonbasal slip and fail by fracture over all conditions tested. The mechanical response of biotite shortened at 45{degree} to (001) is nearly perfectly elastic-plastic; stress-strain curves are characterized by a steep elastic slope, a sharply defined yield point, and continued deformation at low (mostly < 100 MPa), relatively constant stresses at strains >1%. Stresses measured beyond the yield point are insensitive to confining pressure over the range 200 to 500 MPa and exhibit weak dependencies upon strain rate and temperature. Assuming an exponential relationship between differential stress {sigma}{sub d} and strain rate {epsilon} = C exp({minus}Q/RT), the data collected over strain rates and temperatures of 10-7 to 10-4 s-1 and 20 to 400C, respectively, are best fit by an exponential constant {alpha} of 0.41 {plus minus} 0.08 MPa{minus}1 and an activation energy Q of 82 {plus minus} 13 kJ/mol. A power law fits the data equally well with n = 18 {plus minus} 4 and Q = 51 {plus minus} 9 kJ/mol. The strength of biotite shortened perpendicular to (001) exceeds that measured parallel to (001) and is pressure dependent. Application of the results to deformation within the continental crust suggests that biotite oriented favorably for slip is much weaker than most silicates over a wide range of geologic conditions. Its presence within foliated rocks and shear zones may limit locally the stresses that can be supported.

  20. Analysis of Basal Plane Bending and Basal Plane Dislocations in 4H-SiC Single Crystals

    NASA Astrophysics Data System (ADS)

    Ohtani, Noboru; Katsuno, Masakazu; Fujimoto, Tatsuo; Nakabayashi, Masashi; Tsuge, Hiroshi; Yashiro, Hirokatsu; Aigo, Takashi; Hirano, Hosei; Hoshino, Taizo; Ohashi, Wataru

    2009-06-01

    4H-SiC single crystals were grown by the physical vapor transport (PVT) growth method under different thermoelastic stress conditions, and the degree of basal plane bending in the crystals was characterized by the peak shift measurement of X-ray rocking curves. The results indicate that the degree of basal plane bending largely depends on the magnitude of the thermoelastic stresses imposed on the crystals during PVT growth. Quantitative analysis of basal plane bending revealed that the density of basal plane dislocations (BPDs) estimated from basal plane bending is much smaller than that obtained from defect-selective etching. It was also found that the BPD density is correlated with the threading screw dislocation (TSD) density in PVT-grown SiC crystals. These aspects of BPDs were discussed in terms of the BPD multiplication process triggered by the intersection of BPDs with a forest of TSDs extending along the c-axis.

  1. Limbal Basal Cell Density Decreases in Limbal Stem Cell Deficiency

    PubMed Central

    Chan, Eric H; Chen, Luxia; Rao, Jian Yu; Yu, Fei; Deng, Sophie X.

    2016-01-01

    Purpose To investigate changes in limbal basal epithelial cell density in eyes with limbal stem cell deficiency (LSCD) using in vivo confocal laser scanning microscopy Design retrospective observational comparative study Methods A total of 43 eyes of 30 patients diagnosed with LSCD were included in the study. Ten eyes from normal subjects were included as control. Confocal imaging of the central cornea, and the superior, nasal, inferior and temporal limbus were collected using the Heidelberg Retina Tomograph III Rostock Corneal Module. Basal cell density in all locations was measured by two independent observers. Results The mean basal cell density of the normal group was 9264 ±598 cells/mm2 in the cornea and 7120 ±362 cells/mm2 in the limbus. In the LSCD group, the mean basal cell density in the cornea decreased 31.0% (6389 ±1820 cells/mm2, p<0.001) and in the limbus decreased 23.6% (5440 ±1123 cells/mm2, p<0.001) compared to that in the control. There was a trend of basal cell density decline in more advanced stage of LSCD. The basal cell density declined in the unaffected regions at a similar degree as that in the affected region in sectoral LSCD (p>0.05). The basal cell diameter increased by 24.6% in the cornea (14.7 μm) and by 15.7% in the limbus (15.5 μm) compared to the control. Conclusions Basal cell density in both central cornea and limbus decreases in LSCD. LSCs are affected globally and basal cell density could be used as a parameter to measure LSC function at the early stages of the disease process. PMID:26149968

  2. Cortico-Basal Ganglia Circuit Function in Psychiatric Disease.

    PubMed

    Gunaydin, Lisa A; Kreitzer, Anatol C

    2016-01-01

    Circuit dysfunction models of psychiatric disease posit that pathological behavior results from abnormal patterns of electrical activity in specific cells and circuits in the brain. Many psychiatric disorders are associated with abnormal activity in the prefrontal cortex and in the basal ganglia, a set of subcortical nuclei implicated in cognitive and motor control. Here we discuss the role of the basal ganglia and connected prefrontal regions in the etiology and treatment of obsessive-compulsive disorder, anxiety, and depression, emphasizing mechanistic work in rodent behavioral models to dissect causal cortico-basal ganglia circuits underlying discrete behavioral symptom domains relevant to these complex disorders. PMID:26667072

  3. The basal ganglia-circa 1982 - A review and commentary

    NASA Technical Reports Server (NTRS)

    Mehler, W. R.

    1981-01-01

    A review is presented of recent studies which utilize new anterograde and retrograde axon transport methods in order to improve knowledge of the projection of the basal ganglia and to clarify their sites of origin. These studies have thrown new light on certain topographic connectional relationships and have revealed several new reciprocal connections between constituent nuclei of the basal ganglia. Also examined are the many new histochemical techniques that are now providing regional biochemical overlays for connectional maps of the central nervous system, especially regions in or interconnecting with the basal ganglia.

  4. The expanding universe of disorders of the basal ganglia.

    PubMed

    Obeso, Jose A; Rodriguez-Oroz, Maria C; Stamelou, Maria; Bhatia, Kailash P; Burn, David J

    2014-08-01

    The basal ganglia were originally thought to be associated purely with motor control. However, dysfunction and pathology of different regions and circuits are now known to give rise to many clinical manifestations beyond the association of basal ganglia dysfunction with movement disorders. Moreover, disorders that were thought to be caused by dysfunction of the basal ganglia only, such as Parkinson's disease and Huntington's disease, have diverse abnormalities distributed not only in the brain but also in the peripheral and autonomic nervous systems; this knowledge poses new questions and challenges. We discuss advances and the unanswered questions, and ways in which progress might be made. PMID:24954674

  5. Matrix solid-phase dispersion combined with gas chromatography-mass spectrometry for the determination of fifteen halogenated flame retardants in mollusks.

    PubMed

    Villaverde-de-Sáa, Eugenia; Valls-Cantenys, Carme; Quintana, José Benito; Rodil, Rosario; Cela, Rafael

    2013-07-26

    This study presents the development and validation of a new analytical method for the simultaneous determination of fifteen analytes classified as halogenated flame retardants (HFRs) - nine brominated diphenyl ethers (BDEs) and six novel HFRs - in different kinds of mollusks using matrix solid-phase dispersion (MSPD) followed by gas chromatography coupled to negative chemical ionization-mass spectrometry (GC-NCI-MS). The proposed method is the first one developed for such a broad range of HFRs in aquatic biota, featuring several advantages, including low solvent and sample intake, simplicity of operation, reduced cost and integration of extraction and clean-up into a single step. Under optimal conditions, 0.5g of freeze-dried sample, 0.5g of a primary-secondary amine (PSA) as solid support, a sorbent combination of 1.75g of florisil (deactivated with 5% Milli-Q water), 1.75g of acidified silica (10% (w/w) H2SO4) and 0.5g of silica, and 10mL dichloromethane as elution solvent were used. Standard addition over the extract was required however for the correct quantification due to matrix effects in the GC system, particularly for novel HFRs, that could not be compensated with the internal standards. The method afforded LODs in the range of 0.003-0.07ngg(-1) dry weight (0.0006-0.014ngg(-1) on a wet weight basis, assuming an 80% sample water content), except for decabromodiphenyl ethane (DBDPE) (0.6ngg(-1) dry weight, 0.12ngg(-1) wet weight). The accuracy of the method was evaluated with three different types of spiked mollusk species using surrogate standards and standard addition over the extract for quantification and the recoveries were in the 70-120% range, except for bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (DEHTBP) in clam (Ruditapes philippinarum) samples (46% recovery). Moreover, the method was successfully validated with standard reference materials (SRMs) of salmon and mussel tissues for BDEs. Finally, the method was applied to the determination of HFRs

  6. A psittacosaurid-like basal neoceratopsian from the Upper Cretaceous of central China and its implications for basal ceratopsian evolution.

    PubMed

    Zheng, Wenjie; Jin, Xingsheng; Xu, Xing

    2015-01-01

    Psittacosauridae (parrot-beaked dinosaurs) represents the first major radiation of ceratopsians (horned dinosaurs). However, psittacosaurids are divergent from the general morphology found in other ceratopsians, and this has resulted in their uncertain systematic position among ceratopsians. Here we describe a new basal neoceratopsian dinosaur, Mosaiceratops azumai gen. et sp. nov. based on a partial semi-articulated skeleton recovered from the Upper Cretaceous Xiaguan Formation of Neixiang County, Henan Province, China. Although our phylogenetic analysis supports this taxon as the most basal neoceratopsian, Mosaiceratops exhibits many features previously considered unique to the Psittacosauridae among the basal Ceratopsia. These include a relatively highly positioned external naris, a proportionally large premaxilla, the nasal extending ventral to the external naris, slender postorbital and temporal bars, a large notch between the basal tubera, and the edentulous premaxilla. Thus, the discovery of Mosaiceratops reduces the morphological disparity between the Psittacosauridae and other basal ceratopsians. Character optimization suggests that basal neoceratopsians have re-evolved premaxillary teeth; a major reversal previously unknown in any dinosaur clade. The new specimen also highlights the mosaic nature of evolution among early ceratopsians and supports the phylogenetic hypothesis that the Psittacosauridae is a relatively derived clade, rather than the most basal group of the Ceratopsia. PMID:26388024

  7. Genetics Home Reference: familial idiopathic basal ganglia calcification

    MedlinePlus

    ... in regulating phosphate levels within the body (phosphate homeostasis) by transporting phosphate across cell membranes. The SLC20A2 ... link familial idiopathic basal ganglia calcification with phosphate homeostasis. Nat Genet. 2012 Feb 12;44(3):254- ...

  8. Nuclear morphometry and chromatin textural characteristics of basal cell carcinoma*

    PubMed Central

    Mendaçolli, Paola Jung; Brianezi, Gabrielli; Schmitt, Juliano Vilaverde; Marques, Mariângela Esther Alencar; Miot, Hélio Amante

    2015-01-01

    Histological subtypes of basal cell carcinoma have biological, evolutionary and distinct prognostic behavior. The analysis of characteristics of the nucleus can provide data on their cellular physiology and behavior. The authors of this study evaluated nuclear morphological parameters and textural patterns of chromatin from different subtypes of basal cell carcinoma: nodular (n=37), superficial (n=28) and sclerodermiform (n=28). The parameters were compared between neoplasms' subtypes and with unaffected adjacent basal epithelium. Nuclear area and diameter of sclerodermiform neoplasms were superior to the other subtypes. Chromatin's color intensity and fractal dimension were less intense in superficial subtypes. Nuclear roundness and chromatin's entropy presented lower values in tumors than in normal epithelium. There was significant correlation between morphological and textural variables of normal skin and tumors. Morphometric elements and textural chromatin's homogeneity of basal cell carcinomas may be related to evolutionary, biological and behavior particularities related to each histotype. PMID:26734870

  9. Short latency cerebellar modulation of the basal ganglia.

    PubMed

    Chen, Christopher H; Fremont, Rachel; Arteaga-Bracho, Eduardo E; Khodakhah, Kamran

    2014-12-01

    The graceful, purposeful motion of our body is an engineering feat that remains unparalleled in robotic devices using advanced artificial intelligence. Much of the information required for complex movements is generated by the cerebellum and the basal ganglia in conjunction with the cortex. Cerebellum and basal ganglia have been thought to communicate with each other only through slow, multi-synaptic cortical loops, begging the question as to how they coordinate their outputs in real time. We found that the cerebellum rapidly modulates the activity of the striatum via a disynaptic pathway in mice. Under physiological conditions, this short latency pathway was capable of facilitating optimal motor control by allowing the basal ganglia to incorporate time-sensitive cerebellar information and by guiding the sign of cortico-striatal plasticity. Conversely, under pathological condition, this pathway relayed aberrant cerebellar activity to the basal ganglia to cause dystonia. PMID:25402853

  10. [Extensive basal cell cancer of the scalp - case reports].

    PubMed

    Olędzki, Szymon; Modrzejewski, Andrzej; Department Of Surgery And Emergency Nursing Pomeranian Medical University In Szczecin Poland, Ryszard

    2016-07-01

    Basal-cell canceris a slow growing, rarely metastasizes, locally malignant skin cancer. Patients with this neoplasm usually have excellent prognosis. Potentially, in some cases, a good prognosis cause a delay in therapy. Delay or withdrawal from treatment might lead to higher local extension of tumour with the destruction of the surrounding tissue. In this article we are presenting two patients with extensive basal cell cancer. The first patient underwent plastic surgery for extensive basal-cell carcinoma located in the parietal and temporal area. The second patient was observed due to recurrence of extensive basal cell carcinoma in the parietal region. Local advancement of the primary tumor could be a reason for the lack of radicality of surgery. Such advancement is rarely seen nowadays. The cases demonstrate the need for awareness about the possible severe course of the disease. PMID:27590651