scholarly journals Characterization of diurnal urea excretion in the mangrove killifish, Rivulus marmoratus

2006 ◽  
Vol 209 (14) ◽  
pp. 2696-2703 ◽  
Author(s):  
T. M. Rodela
Keyword(s):  
Urea Excretion ◽  
Rivulus Marmoratus ◽  
Mangrove Killifish

Nitrogen metabolism and excretion in the mangrove killifish Rivulus marmoratus I. The influence of environmental salinity and external ammonia

2002 ◽  
Vol 205 (1) ◽  
pp. 79-89 ◽  
Author(s):  
N. T. Frick ◽  
P. A. Wright
Keyword(s):  
Nitrogen Metabolism ◽  
Prolonged Exposure ◽  
Sea Water ◽  
Ammonia Excretion ◽  
Control Fish ◽  
Diurnal Pattern ◽  
Field Site ◽  
Rivulus Marmoratus ◽  
Water Gradient ◽  
Mangrove Killifish

SUMMARY At a field site in Belize, mangrove killifish Rivulus marmoratus inhabit hypersaline waters (up to 48 ‰) containing approximately 1 mmol l–1 ammonia. We tested the hypotheses that R. marmoratus modify their nitrogen metabolism and excretion (i) by accumulating free amino acids (FAAs) and urea in the tissues during hyperosmotic stress and (ii) by shifting to ureotelism and accumulating FAAs during hyperammonia stress. Urea excretion (JUrea) (but not ammonia excretion, JAmm) displayed a diurnal pattern, with significantly less (75 %) urea excreted at night than during the day in both laboratory-reared clones and wild-caught killifish. When fish were exposed to hypersaline conditions (45 ‰ sea water), JUrea was significantly reduced and tissue urea and FAA levels were elevated compared with those of control fish (15 ‰ sea water). When R. marmoratus were exposed to 0, 1, 2, 5 and 10 mmol l–1 NH4Cl (pH 8) for 48 h, no differences were found in JUrea. Remarkably, prolonged exposure (10 days) to 5 mmol l–1 NH4Cl (pH 8) did not result in an elevation of tissue ammonia levels. In addition, tissue urea and total FAA levels did not differ between control and ammonia-exposed fish after ⩾4 days. We propose that the euryhaline R. marmoratus retain urea and FAAs within their tissues in response to extreme osmotic stress. In contrast to many ammonia-tolerant fishes, R. marmoratus do not shift to ureotelism during prolonged hyperammonia stress, nor do they convert nitrogenous wastes into FAAs. The data suggest that killifish continue to eliminate ammonia despite an unfavourable blood-to-water gradient, thereby avoiding accumulation of ammonia.

scholarly journals Genetic and growth differences in the outcrossings between two clonal strains of the self-fertilizing mangrove killifish

2008 ◽  
Vol 86 (9) ◽  
pp. 976-982 ◽  
Author(s):  
Yukino Nakamura ◽  
Koushirou Suga ◽  
Yoshitaka Sakakura ◽  
Takashi Sakamoto ◽  
Atsushi Hagiwara
Keyword(s):  
Artificial Insemination ◽  
Genetic Architecture ◽  
Life History Traits ◽  
Fragment Length Polymorphism ◽  
The Self ◽  
Aflp Analysis ◽  
Rivulus Marmoratus ◽  
Kryptolebias Marmoratus ◽  
Growth Differences ◽  
Mangrove Killifish

The populations of the only known self-fertilizing vertebrate Kryptolebias marmoratus (Poey, 1880) (formerly known as Rivulus marmoratus Poey, 1880; Cyprinodontiformes: Aplocheilidae) usually consist of different homozygous lineages; however, heterozygous individuals are found occasionally and ratios of homozygosity and heterozygosity in populations are dependent on the proportion of males. However, it is still unclear what impact male-mediated genetic diversity has on the phenotype of K. marmoratus. To clarify this, we attempted outcrossing between male and hermaphrodite of two different clonal strains with different life-history traits using artificial insemination, and examined the genotypes and growth of the hybrid F2 generation. We detected genetic differences between the two clonal strains using amplified fragment length polymorphism (AFLP) analysis with 3 primer combinations, and then obtained 11 AFLP markers. From a total of 31 artificial inseminations with two clonal strains, 1 of 13 hatched fish clearly indicated heterozygosity. The hybrid F2 generations were also heterozygous. Moreover, the growths of the hybrid F2 generation were intermediate of the parental strains from days 0 to 30. Therefore, outcrossing changes genetic architecture and the new genotypes potentially result in new phenotypes of the subsequent generations of K. marmoratus. It may also play a role in adaptation to new environments and the facilitation of local adaptation.

scholarly journals Early development of the self-fertilizing mangrove killifish Rivulus marmoratus reared in the laboratory

2004 ◽  
Vol 51 (4) ◽  
pp. 309-315 ◽  
Author(s):  
Maria Vivian Camacho Grageda ◽  
Yoshitaka Sakakura ◽  
Atsushi Hagiwara
Keyword(s):  
Early Development ◽  
The Self ◽  
Rivulus Marmoratus ◽  
Mangrove Killifish

Nitrogen metabolism and excretion in the mangrove killifish Rivulus marmoratus II. Significant ammonia volatilization in a teleost during air-exposure

2002 ◽  
Vol 205 (1) ◽  
pp. 91-100 ◽  
Author(s):  
N. T. Frick ◽  
P. A. Wright
Keyword(s):  
Whole Body ◽  
Carbamoyl Phosphate Synthetase ◽  
Nh3 Volatilization ◽  
Carbamoyl Phosphate ◽  
Air Exposure ◽  
Exposed Fish ◽  
Rivulus Marmoratus ◽  
Body Tissues ◽  
Total Ammonia ◽  
Mangrove Killifish

SUMMARY The mangrove killifish Rivulus marmoratus can tolerate prolonged periods of air-exposure (>1 month). During these periods of emersion, we hypothesized that R. marmoratus would convert potentially toxic ammonia into urea and free amino acids (FAAs). In air-exposed fish, both ammonia (JAmm) and urea (JUrea) excretion continued at approximately 57 % and 39 %, respectively, of submerged rates. Remarkably, approximately 42 % of the total ammonia excreted during air-exposure was through NH3 volatilization. Ammonia did not accumulate in whole-body tissues of air-exposed fish, but levels of both urea and some FAAs (primarily alanine and glutamine) were up to twofold higher after 10 days. The activities of the ornithine–urea cycle enzymes carbamoyl phosphate synthetase III and ornithine transcarbamylase increased (by approximately 30 % and 36 %, respectively) in whole-body tissues of air-exposed fish, while levels of arginase remained unchanged. The activities of enzymes involved in amino acid and oxidative metabolism were not significantly different between control and air-exposed fish. Partitioning of the anterior and posterior ends of immersed fish revealed that just over half (57 %) of the total nitrogen (ammonia+urea) was excreted through the anterior end of the fish, presumably via the branchial tissues, while emersed fish increased excretion via the posterior end (kidney+skin). R. marmoratus do not undergo a shift towards ureotelism during air-exposure. Rather, we propose that R. marmoratus are able to survive on land for extended periods without significant ammonia accumulation because they continuously release ammonia, partially by NH3 volatilization.

Gonadal histology in the self-fertilizing hermaphroditic fish Rivulus marmoratus (Pisces, Cyprinodontidae)

1992 ◽  
Vol 70 (12) ◽  
pp. 2338-2347 ◽  
Author(s):  
Cristina G. Soto ◽  
John F. Leatherland ◽  
David L. G. Noakes
Keyword(s):  
Testicular Tissue ◽  
Gonadal Development ◽  
Rivulus Marmoratus ◽  
Gonadal Histology ◽  
Electron Microscopy Analysis ◽  
Microscopic Studies ◽  
Microscopy Analysis ◽  
Primary Male ◽  
Gonadal Structure

In nature, most individuals of Rivulus marmoratus are reportedly self-fertilizing hermaphrodites. A few rare individuals are males, but females have never been found in the field or laboratory. We describe the gonadal histology of this unique fish, mainly on the basis of light-microscopic studies with some elaboration by electron microscopy. Analysis of gonadal structure and the characterization of the stages of spermatogenesis and oogenesis allowed us to categorize functional gender and to construct the probable sequence of gonadal development in mature individuals. In our laboratory, some hermaphrodites underwent ovarian regression and testicular proliferation to become secondary males. One individual also developed as a primary male. However, the type of male could generally not be distinguished. Testicular tissue composed only a small portion (less than 10%) of the gonad of most hermaphrodites.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

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