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PubMed1994

THE NEURAL CONTROL OF EGG-LAYING BEHAVIOUR IN THE POND SNAIL LYMNAEA STAGNALIS: MOTOR CONTROL OF SHELL TURNING

Behavioural and neurophysiological techniques were used to study the neuronal control of shell turning during egg-laying in the pond snail Lymnaea stagnalis. Egg-laying consists of three phases: resting, turning and oviposition, and is triggered by an electrical discharge in a group of neuroendocrine cells, the caudodorsal cells. During the discharge, several peptides encoded on two CDCH genes are known to be released. Behavioural experiments in which different combinations of nerves were lesioned indicated that the inferior cervical nerves are necessary for turning behaviour to occur. The right inferior cervical nerve innervates the right dorsal longitudinal muscle and contains axons of neurones that are active just prior to, and during, shell movements in freely behaving animals. These axons are probably the axons of motor neurones. The motor neurones of the dorsal longitudinal muscle were identified in the cerebral A and pedal N clusters. We have demonstrated that there is a correlation between the state of excitability of the caudodorsal cells and the electrical activity of the pedal N motor neurones. Our results indicate that the pedal N motor neurones are involved in executing the turning phase during egg-laying.

Journal Article↗
PubMed1995

Bioavailability of calcium from calcium carbonate, DL-calcium lactate, L-calcium lactate and powdered oyster shell calcium in vitamin D-deficient or -replete rats.

The bioavailability of calcium from various calcium sources in humans and animals has been the subject of investigation for many years and there is considerable controversy as to the relative bioavailability of different calcium salts. Most of the studies have used a calcium balance technique which has numerous problems in terms of performance and interpretation. Using a method for evaluating the efficacy of calcium from calcium salts used for plasma calcium metabolism and bone mineralization, we examined the bioavailability of calcium from four commercially available calcium salts, namely calcium carbonate, DL-calcium lactate, L-calcium lactate and powdered oyster shell-calcium in vitamin D-deficient or -replete rats. Among the calcium salts, the differences in bioavailability were small and not statistically significant as tested by analysis of variance in both groups of rats. Thus, we conclude that calcium is utilized to the same extent from calcium carbonate, DL-calcium lactate, L-calcium lactate and powered oyster shell-calcium in both vitamin D-deficient and -replete rats.

Animals↗
PubMed1996

Soluble egg shell membrane protein as a regulating material for collagen matrix reconstruction.

Soluble egg shell membrane protein (SEP) was prepared from egg shell membrane by the combined treatment of performic acid oxidation (4 or 25 degrees C for 24 h) and pepsin digestion (25 degrees C for 24-72 h) before dialyzing against water and lyophilizing. The yield of SEP was about 16-39%. SEP had high contents of acidic amino acids (320-340 residues/1000 residues) containing cysteic acid (101-108 residues) converted from cystine, a small amount of saccharides, a main molecular weight of 12,000-22,000 and pI 4.2-4.8. SEP accelerated the reconstruction of collagen matrix with ordered molecular rearrangement and reduced redissolution of the collagen matrix under several solvent conditions. SEP elevated the denaturation temperature of the matrix.

Amino Acids↗
PubMed2001

Isolation and characterization of the novel lipophilic protein, Pb CP-12.7, from the shell of the pink shrimp, Pandalus borealis.

Past research on diapause-inducing substances of the silkworm has isolated an extremely lipophilic peptide and demonstrated its unique characteristics. In the present work, similar lipophilic proteins were searched for in the shell of the shrimp, Pandalus borealis, and one novel protein, Pb CP-12.7, was isolated. Its structure comprising 126 amino acids was revealed by a combination of a sequence analysis and the enzymic fragmentation technique. Pb CP-12.7 is unique in that it was insoluble in neutral-slightly basic water, but highly soluble in some organic solvents. It contained an abundance of hydrophobic amino acids and repeating sequences. In addition, it was adsorbed to chitin, a major component of the shell of the shrimp.

Adsorption↗
PubMed2002

Purification and identification of flavonoids from the yellow green cocoon shell (Sasamayu) of the silkworm, Bombyx mori.

Three quercetin glycosides, quercetin 5-O-beta-D-glucoside, quercetin 7-O-beta-D-glucoside, and quercetin 4'-O-beta-D-glucoside, and two kaempferol glycosides, kaempferol 5-O-beta-D-glucoside and kaempferol 7-O-beta-D-glucoside, along with their aglycones, quercetin and kaempferol, were isolated from an ethanolic extract of Sasamayu cocoon shells. The chemical structures were characterized by chemical and spectroscopic methods including UV spectrometry and HPLC-ESI-MS. The five flavonol glycosides of the shell are different structurally from those of the leaves of mulberry (Morus alba). It was suggested that potent antioxidative activity in the cocoon is mainly due to flavonoid compounds since free radical scavenging activity was found in the cocoon flavonoids identified here.

Animals↗
PubMed2001

Egg shell ultrastructure of the fish nematode Huffmanela huffmani (Trichosomoididae).

The egg shell of Huffmanela huffmani Moravec, 1987 forms three main layers: an outer vitelline layer, a middle chitinous layer, and an inner lipid layer. The vitelline layer, forming the superficial projections of the egg shell, comprises two parts: an outer electron-dense, and an inner electron-lucid part. The chitinous layer is differentiated into three parts: an outer homogenous electron-dense part, a lamellated part, and an inner electron-dense net-like part. The lipid layer comprises an outer net-like electron-lucid part, and an inner homogenous electron-lucid part. The polar plugs are formed by electron-lucid material with fine electron-dense fibrils.

Air Sacs↗
PubMed2005

Evidence for a highly elastic shell-core organization of cochlear outer hair cells by local membrane indentation.

Cochlear outer hair cells (OHCs) are thought to play an essential role in the high sensitivity and sharp frequency selectivity of the hearing organ by generating forces that amplify the vibrations of this organ at frequencies up to several tens of kHz. This tuning process depends on the mechanical properties of the cochlear partition, which OHC activity has been proposed to modulate on a cycle-by-cycle basis. OHCs have a specialized shell-core ultrastructure believed to be important for the mechanics of these cells and for their unique electromotility properties. Here we use atomic force microscopy to investigate the mechanical properties of isolated living OHCs and to show that indentation mechanics of their membrane is consistent with a shell-core organization. Indentations of OHCs are also found to be highly nonhysteretic at deformation rates of more than 40 microm/s, which suggests the OHC lateral wall is a highly elastic structure, with little viscous dissipation, as would appear to be required in view of the very rapid changes in shape and mechanics OHCs are believed to undergo in vivo.

Animals↗
PubMed1987

Electron microscopic study on the hepatic sinusoidal wall of the soft-shelled turtle (Amyda japonica) with special remarks on the smooth muscle cells.

The hepatic sinusoids of the soft-shelled turtle (Amyda japonica) were examined by transmission electron microscopy. The sinusoidal wall was composed of endothelial cells, Kupffer cells and Ito cells. The basal surface of the hepatocyte facing the Disse's space was covered by a continuous basal lamina. In addition to the Ito cells, the Disse's space contains a considerable number of smooth muscle cells. Many of these were distributed sporadically, while others appeared as a sphincter circling the sinusoid. The smooth muscle cells in the Disse's space showed the following features: 1) The nucleus was located eccentrically near one end of the cell. 2) The surface vesicles and pits, mitochondria and dense patches along the myofilament bundles were all sparse as compared with those known from mammalian smooth muscle cells. 3) Cytoplasmic processes or ruffles were protruded into the Disse's space. 4) A weak basal lamina could be recognized. Sinusoidal endothelial cells were characterized by many large electron lucent lysosomes in their perikaryon and by small fenestrae in their attenuated cytoplasm. Ito cells sending out several cytoplasmic processes, possessed a single large lipid droplet on one side of the nucleus. A single cilium budding from the distal centriole into the Disse's space was found in an Ito cell. Extrasinusoidal macrophages were considerably numerous in the soft-shelled turtle liver. Some of the macrophages were apparently migrating into the sinusoid, there to presumably transform into the Kupffer cells.

Adipose Tissue↗
PubMed2000

The vascular supply of the villiform processes in the pharynx of the soft-shelled turtle, Trionyx sinensis japonicus. A scanning electron microscopic study of corrosion casts.

Following our observations of the fine structure of the pharyngeal villiform processes of the hibernating soft-shelled turtle, Trionyx sinensis japonicus (Yokosuka et al., 2000), this paper deals with a scanning electron microscope study of the resin casts of blood vessels supplying those processes. Each villiform process contained arterioles and venules which ran in the axial portion of the process; capillaries formed a network at the periphery of the connective tissue core of the villus. In the distal portions of the villus, the capillaries increased markedly in their caliber to form sinusoidal capillaries. Such a vascular architecture supports the view that the villiform processes serve in the aquatic respiration of the soft-shelled turtle. The casts indicated an occurrence of sphincters in the vascular bed of the villi.

Animals↗
PubMed1987

Radiographic evaluation of joints resurfaced with osteochondral shell allografts.

The radiographic features of 41 cadaveric osteochondral shell (low ratio of subchondral bone to articular cartilage) allografts placed in 24 patients for articular resurfacing as an alternative to arthroplasty are presented. Underlying causes of joint disease included ischemic necrosis (20 grafts), osteochondritis dissecans (nine), chondromalacia patellae (10), and posttraumatic osteochondral fracture with degenerative disease (two). Congruity with the adjacent native articular surface and the opposite side of the joint was evident on immediate postoperative radiographs in all patients, and proved to be critical to the ultimate success of the procedure. On follow-up radiographs over a period of 2-28 months, successful incorporation of the allograft was characterized by progressive loss of the relative increased density of the graft, in association with diminished lucency related to new bone formation at the graft-native bone interface, as well as maintained alignment. Graft failure was associated with positional changes including collapse, persistent increased density, and poorly defined fragmentation that occasionally simulated infection radiographically and resulted in intraarticular bodies. Resurfacing of diseased articulations with osteochondral shell allografts constitutes a potentially desirable alternative to total joint arthroplasty, particularly among younger patients. Consequently, an awareness of the expected radiographic alterations associated with graft incorporation and failure is important.

Adolescent↗
PubMed2000

Nucleation and growth of calcite on native versus pyrolyzed oyster shell folia.

The thin sheets of calcite, termed folia, that make up much of the shell of an oyster are covered by a layer of discrete globules that has been proposed to consist of agglomerations of protein and mineral. Foliar fragments, treated at 475 degrees C for 36 h to remove organic matter, were imaged by atomic force microscopy (AFM) as crystals grew on the foliar surfaces in artificial seawater at calcite supersaturations up to 52-fold. Crystals were also viewed later by scanning electron microscopy. After pyrolysis, the foliar globules persisted only as fragile remnants that were quickly washed away during AFM imaging, revealing an underlying morphology on the foliar laths of a tightly packed continuum of nanometer-scale protrusions. At intermediate supersaturations, crystal formation was seen immediately almost everywhere on these surfaces, each crystal having the same distinctive shape and orientation, even at the outset with crystals as small as a few nanometers. In contrast, nucleation did not occur readily on non-pyrolyzed foliar surfaces, and the crystals that did grow, although slowly at intermediate supersaturations, had irregular shapes. Possible crystallographic features of foliar laths are considered on the basis of the morphology of ectopic crystals and the atomic patterns of various surfaces. A model for foliar lath formation is presented that includes cycles of pulsed secretion of shell protein, removal of the protein from the mineralizing solution upon binding to mineral, and mineral growth at relatively high supersaturation over a time frame of about 1 h for each turn of the cycle.

Animals↗
PubMed1996

Double-strand breaks in DNA induced by the K-shell ionization of calcium atoms.

A calcium (Ca)-DNA complex in a buffered aqueous solution was irradiated with monochromatic x-rays at around the K-shell absorption edge of the Ca atom. The energies were 4.030 and 4.071 keV, which correspond to slightly below and above the K-shell absorption edge of Ca (4.047 keV). The number of double-strand breaks (DSB) and single-strand breaks (SSB) per one molecule of Col E1 DNA was calculated using Povirk's equation after the electrophoretic separation of three forms of plasmid DNA (forms I, II and III, which are supercoiled closed circular, open circular and linear, respectively). In a solution with Ca ions, the DSB yield in DNA irradiated with 4.071 keV x-rays is 1.27 times higher than that with 4.030 keV x-rays. In contrast, in the absence of Ca ions, the DSB yield is the same at both the x-ray energies. The SSB yields are also independent of the x-ray energy in the presence and absence of Ca ions. A reference experiment regarding irradiation with 60Co gamma-rays shows that the ratio of the DSB yield to the SSB yield upon irradiation with 4.071 keV x-rays is higher (factor of 3.2) than that with 60Co gamma-rays.

Calcium↗
PubMed1996

Lethal effect of K-shell absorption of intracellular phosphorus on wild-type and radiation sensitive mutants of Escherichia coli.

The present study was conducted to clarify the lethality of Auger cascades induced by the K-shell photoabsorption of phosphorus in Escherichia coli. Killing of wild-type and radiation-sensitive mutants of E. coli was examined. Three x-ray energies were chosen for irradiation; at 2.153 keV: the resonance peak of K-shell photoabsorption of phosphorus; at 2.146 and 2.160 keV: off-peak. Enhancement ratio, which was defined as the ratio of the killing sensitivity of 2.153 keV to that at 2.146 keV, were 1.32 to 1.54 for examined strains. Increment of absorbed energy calculated in entire cells for 2.153 keV radiation could not explain the degree of observed enhancement of killing. Lethality of Auger cascades depended on the killing sensitivity with x-rays which did not induce Auger cascades. The lethality for wild-type was lower than that for recombination repair-deficient mutants. It was concluded that one part of damages produced by Auger cascades was repaired in wild-type strains.

Absorption↗
PubMed1987

A method for cytogenetic and cytological examination of small shelled larvae of bivalves and other zooplankton.

Studies on chromosomes and nuclei of very small bivalve larvae have been impeded by the veliger shell. It has been determined that the alcohol:acetic acid fixative commonly used in cytogenetic techniques can be made to act as a decalcifying agent upon repeated heating. In addition, transfer of formalin fixed shelled specimens, routinely used as marine bioassay organisms, into ethyl alcohol:acetic acid (3:1) fixative also yields clear cells for cytological examination of decalcified but otherwise intact oyster larvae and other zooplankton. Identification of cell type, such as germ-line primordia, in, for example, reproductive and ploidy level studies, and observations on the presence of bacteria can be made from the preparations. Material can be examined up to at least a year after preservation. The method is evaluated and its modifications are discussed.

Acetates↗
PubMed1996

The milk-alkali syndrome caused by betelnuts in oyster shell paste.

BACKGROUND: The carcinogenic effect of betelnut chewing leading to oral cancer is well known. Betelnut chewing may also affect the autonomic nervous system. In this report, we present another potential hazard of betelnuts, milk-alkali syndrome. CASE REPORT: Two patients who had chewed a large quantity of betelnuts developed hypercalcemia, metabolic alkalosis, and renal insufficiency. They ingested a large amount of calcium carbonate from a local special paste used for betelnut preparation, the main ingredient of which is ground oyster shell. The symptoms and metabolic abnormalities disappeared promptly after abstinence from betelnut chewing and administration of saline solution. Improvement of renal function was observed in both patients. Analysis of the calcium content of the paste suggested that the patients might have ingested 9 g and 6 g of calcium carbonate per day, respectively. CONCLUSION: This is the first report of milk-alkali syndrome not caused iatrogenically, but by recreational usage of oyster shell preparations of betelnuts.

Areca↗
PubMed2006

Isolation of Fonsecaea pedrosoi from the shell of the babassu coconut (Orbignya phalerata Martius) in the Amazon region of Maranhão Brazil.

Fonsecaea pedrosoi, a dematiaceous fungus and the main causative agent of chromoblastomycosis, has been isolated in worldwide from different natural sources in regions where the disease is endemic. In the Amazon region of Maranhão, Brazil, where the disease is prevalent, the breaking of the babassu coconut (Orbignya phalerata Martius) represents an important agricultural activity. In order to determine the presence of this fungus on this plant and on other natural substrates, material was collected in the Fortaleza Village Municipality of Pinheiro, Maranhão, in April and September 2002. A total of 68 samples, including 18 (26.5%) obtained from the shell of the babassu coconut, were analyzed. Samples were cultured using a standard method. Isolates were identified based on macromorphological aspects of the colonies on Sabouraud dextrose agar and based on the micromorphology of the conidia after growth on potato dextrose agar. Exophiala sp. was the most prevalent fungus isolated from the different natural substrates analyzed, while Cladophialophora sp. was only isolated from decomposing wood. Fonsecaea pedrosoi was isolated from one sample of babassu coconut shell suggesting that this coconut represents an important source of infection of chromoblastomycosis during extraction of the plant product in this region.

Ascomycota↗
PubMed2000

A new shell disease in the mud crab Scylla serrata from Port Curtis, Queensland (Australia).

In 1994 a previously unreported rust spot shell disease was seen in mud crabs Scylla serrata - Forskal from Port Curtis, central Queensland, Australia. Of 673 crabs surveyed, 21.7% had shell lesions. Of these, 82.9% had rust spot lesions on the carapace. The majority of rust spot-affected crabs (78.8%) were female. Rust spot lesions were predominantly non-perforated (89.4%) and 54.8% were bilaterally symmetrical. There was also a gender difference in the areas of the carapace most commonly affected. The main histological features of the rust spot lesion included: a cavity in the upper endocuticle; indentation of the endocuticle below the cavity; remains of muscle attachment adhesive epithelium within the cavity; fibrous connective tissue between the damaged carapace and the attached muscle; and islands of endocuticle in this fibrous connective tissue. Histopathology of the internal organs failed to find evidence of an infectious or parasitic cause of the rust spot lesions. The cause(s) of the syndrome appear(s) to be non-infectious.

Animals↗
PubMed1982

Long-term shell-less culture of turkey embryos.

A technique is described for the long-term shell-less culture of turkey embryos. Cultured embryos demonstrated a similar rate of growth through 17 days of total incubation (4 days in ovo plus 13 days in culture) compared to embryos incubated in ovo. Thereafter, the cultured embryos grew at a reduced rate compared to their in ovo counterparts. Cultured embryos also exhibited elevated hematocrit values but reduced serum protein levels compared to the embryos incubated in ovo. Serum zinc, copper, and iron concentrations were similar for both groups of embryos, although each element reached a maximum concentration at a different point during incubation. Embryos incubated in ovo demonstrated a sustained elevation of serum calcium concentration from day 16 of incubation that was absent in the cultured embryos. The significance of eggshell calcium stores to embryo growth is discussed. Shell-less avian embryo culture represents a potentially useful technique for the study of trace element metabolism during avian embryonic growth and development.

Animals↗