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161.
Apoptosis in marine sponges: a biomarker for environmental stress (cadmium and bacteria) 总被引:7,自引:0,他引:7
C. Wagner R. Steffen C. Koziol R. Batel M. Lacorn H. Steinhart T. Simat W. E. G. Müller 《Marine Biology》1998,131(3):411-421
The marine demosponge Suberites domuncula is abundantly present on muddy sand bottoms, both in the open sea and in harbors. In the present study it is shown that exposure
of S. domuncula to cadmium (CdCl2) in concentrations ranging from 0.01 to 5.0 g ml−1 for up to 5 d results in apoptotic fragmentation of DNA. Kinetics experiments revealed that after 24 h a significant increase
of DNA fragmentation already occurred. Besides cadmium a second stimulus was identified to also cause apoptosis in this species,
namely exposure to heat-treated Escherichia coli. In order to support the finding that both cadmium and E. coli induce apoptosis in the sponge, expression of the apoptotic gene MA-3 was studied. The cDNA, SDMA3, was isolated and found to be 2247 nucleotides long. The deduced amino acid sequence (Mr 50 765) shares high similarity with the corresponding mouse molecule. Like the mouse gene, the sponge MA-3 gene undergoes increased expression in response to apoptotic stimuli. While the specimens remained alive after treatment
with cadmium, the sponges treated with E. coli died after approximately 12 d. The E. coli-treated animals started to form gemmules 10 to 12 d after addition of the bacteria. Hence, the process of apoptosis in sponges
is triggered by two different pathways, one which is initiated by exogenous factors, e.g. heavy metals, and a second one,
caused by endogenous factors, which leads to gemmule formation and a shift of the presumably immortal cells to mortal cells.
The latter assumption is supported by the finding that during the process of bacteria-induced apoptosis, which results in
the death of the specimens, the activity of the telomerase drops. It is concluded that the cells which appear to be immortal
and telomerase-positive undergo apoptosis during the process of gemmule formation. In consequence cells not involved in the
production of gemmules become mortal. Based on these data, it is proposed that apoptosis is a suitable biomarker in the bioindicator
organism S. domuncula to monitor unfavorable environmental conditions, at least in this animal phylum.
Received: 10 November 1997 / Accepted: 6 March 1998 相似文献
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163.
Samira Veiga Ravaiano Wagner Faria Barbosa Lúcio Antônio Campos Gustavo Ferreira Martins 《Die Naturwissenschaften》2018,105(7-8):48
The insect immune system faces various challenges; particularly in social bees, caste system and age polyethism expose individuals to numerous environmental and working conditions. However, little is known about how cellular defenses in social bees may be organized to respond to a variety of immune challenges. Here, we describe the morphological features and the total and differential counts of hemocytes in different female classes (newly emerged workers, nurses, foragers, and virgin queens) of the eusocial stingless bee Melipona quadrifasciata. Granulocytes and prohemocytes were, respectively, the most and the least abundant cells among all classes of females. Furthermore, there were more prohemocytes in virgin queens than in foragers. The total number of hemocytes was smaller in foragers, whereas the largest number was observed in nurse workers. This reduced amount of hemocytes in foragers might allow energy savings to perform colony activities such as foraging and defense. Foragers also had the biggest hemocytes (either prohemocytes, granulocytes, or plasmatocytes) in comparison to the other classes of females, which might have arisen as a compensation for the reduction in number of these cells during aging. These results suggest that profiles of hemocytes of M. quadrifasciata vary according to the caste and age of this eusocial bee. 相似文献
164.
L. Hughes B. Siew-Woon Chang D. Wagner N. E. Pierce 《Behavioral ecology and sociobiology》2000,47(3):119-128
The mating system of the Australian lycaenid butterfly, Jalmenus evagoras, is highly unusual compared to most other Lepidoptera. Characteristics of this system, which has been termed an ’explosive
mating strategy,’ include the formation of an intensely competitive mating aggregation of males, a highly male biased operational
sex ratio, a lack of discrimination and mate choice by both sexes, a high variance in male mating success, and female monogamy.
In this study, we tested the hypothesis that multiple mating by males imposes physiological costs resulting in smaller spermatophores,
and that this results in a fitness cost to females. We found that male J. evagoras transferred only 2.2% of their eclosion weight during their first mating, consistent with the hypothesis that males of monandrous
species produce a relatively small investment. The wet weight of the ejaculate declined by an average of 27% at the second
mating and the dry weight by 29%, and an intermating interval of 5–9 days was needed for the ejaculate to return to the size
at the first mating, regardless of male size or age. Wet ejaculate mass increased proportionally with male size, though dry
mass was proportionally larger in smaller males. Ejaculate mass tended to increase with male age at both first and second
matings. Female characteristics, in general, did not affect ejaculate mass, although the wet weight of the ejaculate was positively
associated with female weight at the second mating. Copulation duration increased from 2.4 h to approximately 3 h at the second
mating, and to over 4 h at the third and fourth matings. Fecundity was positively correlated with female size but not with
mating history, copulation duration, or any other characteristics measured for either males or females. Female longevity declined
significantly as the number of times the male partner had previously mated increased. We conclude that despite the small male
investment in ejaculate, the costs of multiple mating may nonetheless be significant, as indicated by the reduction in ejaculate
mass, an increase in copulation duration, and reduction in female lifespan with increasing mating number.
Received: 22 January 1999 / Received in revised form: 28 July 1999 / Accepted: 18 September 1999 相似文献
165.
Kelly KE Wagner DA Lighty JS Sarofim AF Rogers CF Sagebiel J Zielinska B Arnott WP Palmer G 《Journal of the Air & Waste Management Association (1995)》2003,53(3):273-282
Diluted exhaust from selected military aircraft ground-support equipment (AGE) was analyzed for particulate mass, elemental carbon (EC) and organic carbon (OC), SO4(2-), and size distributions. The experiments occurred at idle and load conditions and utilized a chassis dynamometer. The selected AGE vehicles operated on gasoline, diesel, and JP-8. These military vehicles exhibited concentrations, size distributions, and emission factors in the same range as those reported for nonmilitary vehicles. The diesel and JP-8 emission rates for PM ranged from 0.092 to 1.1 g/kg fuel. The EC contributed less and the OC contributed more to the particulate mass than reported in recent studies of vehicle emissions. Overall, the particle size distribution varied significantly with engine condition, with the number of accumulation mode particles and the count median diameter (CMD) increasing as engine load increased. The SO4(2-) analyses showed that the distribution of SO4(2-) mass mirrored the distribution of particle mass. 相似文献
166.
Jacob Wagner Jensen Claus Felby Henning Jørgensen Georg Ørnskov Rønsch Nanna Dreyer Nørholm 《Waste management (New York, N.Y.)》2010,30(12):2497-2503
The focus of this work was to investigate an enzymatic liquefaction of MSW organics, paper and cardboard. Liquefaction trials were conducted in different trial volumes: 50 g lab-scale trials and 50 kg vessel-tests and evaluated based on particle size and viscosity. The viscosity results showed that Celluclast 1.5 L had the singular significant effect on liquefaction of model MSW. No effect of α-amylase, protease and interaction in between and with cellulases on viscosity and particle size distribution was found in this study. Degradable material with a particle size above 1 mm after treatment was evaluated using SEM microscopy. These results showed that paper particles were the main obstacles needing additional treatment in order to become fully liquefied. In a pilot scale test treating authentic MSW; more than 90% of initial organic and paper dry matter (DM) was recovered as liquid slurry after sieving through a 5-mm sieve. These tests were performed at up to 35% DM, showing that this process can easily manage high DM loadings. MSW enzymatic liquefaction promotes the separation of organics and paper from solids, which facilitate the use of these degradable fractions, with minimal loss, capable to enter a biogas plant through existing pipes. 相似文献
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