Changes in Ionic Composition of Media During Culture of Bulinus tropicus and the Relationship Between Ion Concentrations and Inhibition of Growth and Egg-Laying

1990 ◽  
Vol 27 (1) ◽  
pp. 30 ◽  
Author(s):  
D. R. James ◽  
E. Morgan ◽  
D. J. Candy
2017 ◽  
Vol 149 (10) ◽  
pp. 911-920 ◽  
Author(s):  
Osvaldo Alvarez ◽  
Ramon Latorre

In 1943, David Goldman published a seminal paper in The Journal of General Physiology that reported a concise expression for the membrane current as a function of ion concentrations and voltage. This body of work was, and still is, the theoretical pillar used to interpret the relationship between a cell’s membrane potential and its external and/or internal ionic composition. Here, we describe from an historical perspective the theory underlying the constant-field equation and its application to membrane ion transport.


1972 ◽  
Vol 104 (7) ◽  
pp. 1055-1071 ◽  
Author(s):  
Akira Mutuura

AbstractIn the phylogenetic classification of the Lepidoptera, the position of the genital opening and its modifications help to clarify the relationship of the Zeugloptera to the lepidopterous suborders. Three different systems of the suborder classification of the Lepidoptera, into Homoneura and Heteroneura (Tillyard, Imms, etc.), Monotrysia and Ditrysia (Borner), and Dacnonypha, Monotrysia, and Ditrysia (Hinton), are not supported by evidence obtained in the study of the female genitalia.The development of the female terminalia is closely associated with the mode of oviposition. Several types of female terminalia are found in the primitive Lepidoptera (Hepialidae, Neopseustidae, Tischeriidae, Lyonetiidae, Agathiphagidae, Tineidae, Nepticulidae, and Eriocraniidae). They are divided into four categories: hepialid type — the eggs are dropped randomly; typical lepidopterous type — the eggs are laid on the surface of food plants; eriocraniid type — the eggs are laid inside the food plants; tineid type — the eggs are laid in crevices of food. Each of the types is derivable from the types occurring in Neopseustidae, Tischeriidae, Agathiphagidae, and Eriocraniidae, respectively. These types are still far removed from the type of female terminalia in Micropterygidae of the Zeugloptera.The modes of egg-laying as well as the morphological characters of the female genitalia must be taken into consideration in suborder classification of the Lepidoptera.A genealogical tree based on the female terminalia suggests four main branches: hepialid branch — includes Neopseustidae and Prototheoridae; typical lepidopterous branch — includes all Ditrysia and Nepticulidae; tineid branch — includes only Tineidae; eriocraniid branch — includes Incurvariidae, Prodoxidae, Adelidae, and Heliozelidae.


Behaviour ◽  
1975 ◽  
Vol 54 (3-4) ◽  
pp. 258-277 ◽  
Author(s):  
Jean Pouzat

AbstractA resume is made of the major sequences of egg-laying behaviour, both in nature and on stored seeds, of the bean weevil. An experimental analysis of the role of the ovipositor in the act of egg-laying is then undertaken by simple techniques. It is observed that an important stimulus, with respect to this, is mechanical in nature: resulting from contact between the setae of the ovipositor on the one hand, and the seed and the "ground" on the other. Simply suspending the seed instead of leaving it lie on the cage bottom, suffices to reduce egg-laying and production significantly. Examination of egg-laying, when the substratum furnished is a trellis with suitable sized mesh, shows that an important aspect of the mechanical stimulus is in its concentrical character, i.e., the fact that it is applied to a greater number of setae all around the ovipositor. The result enables us to understand better the behaviour in nature, where there is a boring of the bean pod followed by egg-laying inside that pod through through the hole made. In the course of the paper some connected problems are evoked: - The relationship between egg-laying and production; - The more or less necessary character of the succession of the different sequences in egg-laying behaviour. Existence of intermediary cases, between individuals which can lay eggs only in the pod and those laying in the apparent absence of any stimulus, particularly stimuli connected with the bean; - Links between the phytophage and its host, remarks on the apparently unfavourable peculiarity of laying a great number of eggs in the same place, the possible consequences with respect to population dynamics.


1973 ◽  
Vol 80 (3) ◽  
pp. 503-509 ◽  
Author(s):  
H. J. Swatland ◽  
R. G. Cassens

SummaryEighteen foetal sheep were used to study the relationship between suboptimal growth and linear size of skeletal units, dry weights of representative muscles and muscle histology. Foetuses with suboptimal growth caused by inadequate maternal nutrition and competition with other foetuses showed a decrease in skeletomuscular growth although allometric growth was not affected. A slight correlation (r =0·14, P < 0·005) existed between dry weight of the longissimus dorsi and mean minimum myofibre diameter. On morphological evidence, myofibre hyperplasia was thought to be complete by approximately 80 days gestation in all foetuses. Increases in the number of myofibres crossing mid-length transverse sections of the sartorius occurred after this time but were thought to be due to intrafascicularly terminating myofibres growing in length. Suboptimal muscle growth of foetuses in the latter third of gestation was thought to be associated with an inhibition of growth in length of intrafascicularly terminating myofibres.


Author(s):  
Adriana L. Vega ◽  
Hai Yao ◽  
Marc-Antoine Justiz ◽  
Weiyong Gu

Specific electrical conductivity, a material property of biological tissues, has been found to be greater in tumor tissue than in normal tissue on account of its higher water content [1]. Its value is related to water content, ion concentrations, and ion diffusivities within biological tissues [e.g., 1,2,3]. The variation in conductivity with water content is hypothesized to be related to the change in ion diffusivities [5,6]. The objective of this study is to investigate the relationship between conductivity and water content in hydrogels. The main goal is to develop a similar relationship for biological tissues and to understand deformation-dependent ion diffusivity in tissues under mechanical loading.


2008 ◽  
Vol 29 (4) ◽  
pp. 457-462 ◽  
Author(s):  
Edmée Engel ◽  
Klaus Groh ◽  
Richard Griffiths ◽  
Laura Wood ◽  
Laurent Schley

Abstract Small freshwater mussels are sometimes found attached to the toes of aquatic phase amphibians, but the ecological implications of this interspecific relationship are unknown. Toe condition and mussel presence were recorded for newts caught in 37 ponds in Luxembourg between March and June 2007. All four local newt species were affected (Lissotriton helveticus, L. vulgaris, Mesotriton alpestris and Triturus cristatus), primarily by the mussel Sphaerium nucleus but also by Pisidium subtruncatum. Mussel attachment was observed in three ponds, with a particularly high occurrence in one pond, where 23% of newts were affected and significantly more toes were damaged than in other ponds. Mussels caused local tissue and bone damage to their host and may interfere with egg-laying. Twenty-two newts with attached mussels were observed in aquaria for up to 3 days: 13 mussels detached when the newt's toe fell off and nine remained attached. If the mussels benefit from the interaction through, for example, enhanced dispersal then the relationship between the two taxa represents a novel form of parasitism.


2008 ◽  
Vol 47-50 ◽  
pp. 73-76 ◽  
Author(s):  
Fang Chao Xu ◽  
Kazuhiro Kusukawa

Thin films of lead-free piezoelectric ceramics (Bi1/2Na1/2)TiO3 (abbreviated as BNT) were prepared on pure titanium substrates by a hydrothermal method. Several properties of BNT films synthesized in various Bi3+ and Ti4+ concentrations of starting materials were investigated using SEM, EDX, XRD and other instruments. Moreover, the effects of ion concentrations of starting materials on permittivity and piezoelectric effect of BNT films were discussed. The Bi2O3 crystals were more deposited on the surface of films with the increase of the concentration of Bi3+. The relationship between the deflection and applied electric field was measured on unimorph cantilever type actuators made from three samples which had different XRD patterns. The results showed that the piezoelectric effect of BNT films was dependent on the crystallization level of BNT.


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