Effects of sulphuric acid exposure on the behaviour of largemouth bass,Micropterus salmoides

Synopsis Young-of-the-year largemouth bass,Micropterus salmoides, were exposed to four concentrations of sulphuric acid (pH levels 7.2, 6.1, 4.8, and 3.7) for 30 days, and the frequencies of feeding acts and activity bouts, and time budgets were recorded. Juveniles at pH 6.1 and at pH 4.8 performed the two feeding acts, bites and orientations, more often, and spent more time feeding than bass at pH 7.2. Bass at pH 3.7, however, reduced feeding, and spent a significantly larger portion of their time hovering in the water column. Frequencies of comfort and agonistic acts increased with a decline in pH. Alterations of behavioural repertoires of young-of-the-year largemouth bass were useful indicators of sulphuric acid exposure.     

Fertile heteroallelic combinations of mutant alleles of the otu locus of Drosophila melanogaster

Summary This paper describes the ovarian pathologies observed when 108 different heteroallelic combinations were made involving 17 independent mutations at the ovarian tumor (otu) locus. Most of the mutant phenotypes can be explained as graded responses by individual germ cells to different levels of functionally active otu gene product (OGP) synthesized by the mutant cells themselves. The lowest and highest levels of OGP appear to be produced by otu ¹⁰ and otu ¹⁴, respectively. In most heteroallelic ovaries the alleles have additive effects, and hybrid germ cells reach a developmental stage more advanced than the weaker homozygote but less advanced than the stronger homozygote. However, examples of both positive and negative complementation also have been found, and these suggest that the products encoded by different mutant alleles can combine to form dimers or multimers which may be superior or inferior to the homodimers. In flies homozygous for otu ¹¹ most ovarioles contain tumors, but some germ cells are able to develop further than those in otu ¹⁴ homozygotes. This suggests that, while otu ¹¹ produces intermediate levels of OGP, it also produces a second product (which otu ¹⁴ cannot make) that is utilized at the period in oogenesis when development in cells homozygous for otu ¹⁴ is blocked. When otu ¹¹ is combined with any one of eight specific alleles, it allows oocyte/nurse cell syncytia to differentiate that can complete development and undergo embryogenesis, if fertilized. The endopolyploid nurse cells of these hybrids have giant polytene chromosomes, and the presence of GPCs in functionally active, germ-line derived cells provides an interesting new system for experimental study. Analysis of the characteristic ovarian pathologies produced by flies of different genotypes leads to the conclusion that the products of the otu ⁺ gene are utilized during at least six different periods in Drosophila oogenesis.     

Extensive degradation of Aroclors and environmentally transformed polychlorinated biphenyls by Alcaligenes eutrophus H850.

We have isolated and characterized a strain of Alcaligenes eurtrophus, designated H850, that rapidly degrades a broad and unusual spectrum of polychlorinated biphenyls (PCBs) including many tetra- and pentachlorobiphenyls and several hexachlorobiphenyls. This strain, which was isolated from PCB-containing dredge spoils by enrichment on biphenyl, grows well on biphenyl and 2-chlorobiphenyl but poorly on 3- and 4-chlorobiphenyl. Capillary gas-chromatographic analysis showed that biphenyl-grown resting cells of H850 degraded the components of 38 of the 41 largest peaks of Aroclor 1242 and 15 of the 44 largest peaks of Aroclor 1254, resulting in an overall reduction of PCBs by 81% for Aroclor 1242 (10 ppm) and 35% for Aroclor 1254 (10 ppm) in 2 days. Furthermore, H850 metabolized the predominantly ortho-substituted PCB congeners that resulted from the environmental transformation of the more highly chlorinated congeners of Aroclor 1242 by the upper Hudson River anaerobic meta-, para-dechlorination agent system C (J. F. Brown, R. E. Wagner, Jr., D. L. Bedard, M. J. Brennan, J. C. Carnahan, R. J. May, and J. J. Tofflemire, Northeast Environ. Sci. 3:167-179, 1984). The congener selectivity patterns indicate that a two-step process consisting of anaerobic dechlorination followed by oxidation by H850 can effectively degrade all of the congeners in Aroclor 1242 and possibly all those in Aroclor 1254.     

The entrapment of [14C]ascorbic acid in human erythrocytes

Radioactively labelled ascorbic acid and dehydroascorbic acid, when incubated with human blood, migrate irreversibly into human red blood cells. Isolation and characterization of the moieties trapped within the cells via infrared spectroscopy established both their identities as L-ascorbic acid. Evidence in the form of the degree of in vitro entrapment of ascorbic acid as a function of the times of incubation and the effect of incubation temperature, anion recognition site inhibitor, and active transport inhibitor on the rate of entrapment support the hypothesis that ascorbic acid is oxidized on or near the surface of the red blood cell to dehydroascorbic acid which migrates through the lipid portion of the cell wall and is reduced back to ascorbic acid within the cell. The resulting L-ascorbic acid can not pass through the cell wall and is therefore entrapped.     

Coreconstitution of bacterial ATP synthase with monomeric bacteriorhodopsin into liposomes. A comparison between the efficiency of monomeric bacteriorhodopsin and purple membrane patches in coreconstitution experiments

The conditions for coreconstitution of a bacterial ATP synthase and bacteriorhodopsin into lecithin liposomes and for light driven ATP synthesis have been optimized. A rate of maximally 280 nmol ATP min-1 mg ATP synthase-1 was achieved with monomerized bacteriorhodopsin compared with a rate of up to 45 nmol ATP min-1 mg-1 found for proteoliposomes containing bacteriorhodopsin in the form of purple membrane patches. The different rates are explained by the finding that monomeric bacteriorhodopsin is more homogeneously distributed among the liposomes than the purple membrane patches. The final activities depended on both the purification method for the two proteins and the coreconstitution procedure. Furthermore, the ratio (lipid to bacteriorhodopsin to ATP synthase) could be optimized. Light-driven ATP synthesis depends also on the type of detergent used. The best result was obtained by deoxycholate. Also the relationship between proton translocation (by bacteriorhodopsin) and ATP synthesis activity was measured. A constant H+/ATP ratio was found at higher light intensities. This ratio increased strongly at lower light intensities.     

Aging alterations in the modulation of central dopaminergic cilioinhibition by etorphine in the marine mussel,Mytilus edulis: Decrease in the inhibition of presynaptic dopamine release

1. This report further demonstrates that etorphine influences presynaptic dopamine release, which in turn centrally modulates peripheral cilioinhibition. 2. In older animals cilioinhibition has become enhanced due to a lack of responsiveness to endogenous opioids which results in greater dopamine release, causing a higher level of cilioinhibition as demonstrated by challenging the visceral ganglia with etorphine or destroying the dopaminergic component with 6-hydroxydopamine. 3. Only the central cilioinhibitory, not the peripheral inhibitory response, mechanism appears to be altered in older animals. Thus, the alteration appears in the central integrative mechanisms involved with regulating ciliary activity. 4. The KCl-stimulated release of dopamine is unaltered in both young and old organisms, whereas the opiate inhibition of the KCl-stimulated release of dopamine is reduced in older organisms. Thus, the aging-associated alteration is associated with a specific process. 5. The reduction of opioid influence and the resulting enhanced cilioinhibitory activity may make the organisms more susceptible to environmental stress.