Effect of temperature on locomotor activity in the goldfish (Carassius auratus) and the bluegill (Lepomis macrochirus): Presence of an ‘activity well’ in the region of the final preferendum

Goldfish (Carassius auratus) and bluegill sunfish (Lepomis macrochirus) were placed in aquaria where their locomotor activity was monitored by photocells, and tested at various acclimation temperatures over a range encompassing their final thermal preferenda. Activity was pooled over 24-hour periods to eliminate any circadian rhythm effects. Both species exhibited an activity well of reduced locomotor activity in the region of the final preferendum. Goldfish, tested either singly or in groups of 2–5 individuals, exhibited a social-interaction effect which became more pronounced at higher temperatures. These results are discussed in relation to a thermokinetic interpretation of thermo-regulatory behavior in fishes, and to the correspondence between thermal preferenda and thermal optima.     

Thermoregulatory behavior of the bluespotted sunfish,Enneacanthus Gloriousus

Twenty bluespotted sunfish, Enneacanthus gloriosus, were individually tested for thermoregulatory behavior in an electronic shuttlebox. The first fishes of this genus to be tested for thermoregulatory behavior, these individuals were captured near the northern limit of their zoogeographic range, in northeastern Pennsylvania. The mean final preferendum from pooled data of all 20 fish was 28.5°C; there were no significant differences between day and night.     

Effects of Cerulenin upon the Syntheses of Lipid and Protein and upon the Formation of Respiratory Enzymes in Adapting, Lipid-Limited Saccharomyces cerevisiae

When bakers' yeast cells were grown anaerobically in a medium supplemented with Tween 80 and ergosterol, exposure during aeration to the fatty acid synthesis inhibitor, cerulenin, had little effect upon respiratory adaptation, the induction of enzymes of electron transport, or the in vivo incorporation of [(14)C]leucine into mitochondrial membranes. These lipid-supplemented cells were apparently able to undergo normal respiratory adaptation utilizing endogenous lipids alone. The level of cerulenin used (2 mug/ml) inhibited the in vivo incorporation of [(14)C]acetate into mitochondrial membrane lipids by 96%. If, however, the cells were deprived of exogenous lipid during anaerobic growth, subsequent exposure to cerulenin severely reduced their capacity to undergo respiratory adaptation, to form enzymes of electron transport, and to incorporate amino acid into both total cell and mitochondrial membrane proteins. This cerulenin-mediated inhibition of enzyme formation and of protein synthesis was nearly completely reversed by the addition of exogenous lipid during the aeration of the cells. In lipid-limited cells, chloramphenicol also had dramatic inhibitory effects, both alone (75%) and together with cerulenin (85%), upon total cell and mitochondrial membrane [(14)C]leucine incorporation. This marked chloramphenicol-mediated inhibition was also largely reversed by exogenous lipid. It is concluded that, in lipid-limited cells, either cerulenin or chloramphenicol may prevent the emergence of a pattern of lipids required for normal levels of protein synthetic activity. The effect of cerulenin upon the formation of mitochondrial inner membrane enzymes thus appears to reflect a nonspecific effect of this antilipogenic antibiotic upon total cell protein synthesis.     

SPECIAL PAPER: THE PLASTOCHRON INDEX: A REVIEW AFTER TWO DECADES OF USE

The plastochron index provides a morphological time scale which has proved more reliable than chronological age in studies relating morphological and physiological development of a whole plant or plant organ. Since its inception in 1957, the index has been utilized in a variety of investigations from leaf ontogeny in cottonwood trees to rhizoid cluster initiation in algae. The plastochron index has been extensively used in studies involving source and sink relationships, leaf anatomy, cell differentiation, and primary vascularization. It has been used in investigations of hormonal regulation of plant growth and in studies of the effects of various environmental factors on developmental processes in crops. This paper reviews some of the literature from 1957 to present concerning the development and use of the plastochron index.     

Therapy for Cancer of the Breast: Current Status of Steroid Hormone Receptors

Estrogen receptor (ER) assays in human breast cancer tissue have proved useful in selecting patients for endocrine therapies. The absence of ER indicates hormone independent tumors and precludes the use of endocrine therapy. Patients with positive tumor ER respond to endocrine therapy at nearly twice the rate of those patients chosen by clinical criteria, although about a third of ER positive tumors in patients still do not respond. Recently, research has been directed toward increasing the accuracy of the ER assay in the ER positive group. The absolute tumor ER value and the presence of progesterone receptor appear promising in this regard. The significance of nuclear estrogen receptor is being studied. Finally, the ER status of a primary breast tumor appears to be a marker for the length of time until recurrence after mastectomy, and for survival. The ER assay may prove valuable in planning new adjuvants in the treatment of breast cancer.     

Haem transport to the liver by haemopexin. Receptor-mediated uptake with recycling of the protein

Rat [(59)Fe]haem-(125)I-labelled haemopexin complexes (700pmol/rat) associate rapidly and exclusively with the liver after intravenous injection into anaesthetized rats. The two isotopes exhibit different patterns of accumulation. Liver (125)I-labelled haemopexin is maximum 10min after injection (20+/-4.9pmol/g of liver) and then declines by 2h to the low values (about 3pmol/g of liver) seen after injection of the apoprotein. In contrast, [(59)Fe]haem accumulates in the liver for at least 2h. Haemopexin undergoes no extensive proteolysis during 2h of haem transport as shown by precipitation with acid (98%) and specific antiserum (92%) and by electrophoresis. Moreover, only 1-2% of the dose is located in extrahepatic tissues, and there is no significant urinary excretion of either (125)I or (59)Fe. Hepatic uptake at 10min is saturable, reaching 200pmol of haemopexin/g of liver and 350pmol of haem/g of liver at a dose of 9nmol/rat, whereas uptake of the apoprotein is 3-5% of the dose. This suggests that the interaction of haem-haemopexin with the liver is a specific receptor-mediated process. The complex probably interacts via the protein moiety, since the haem analogues mesohaem and deuterohaem do not affect association of the protein with the liver but the species of haemopexin does. Increasing amounts of protein are associated with the liver 5min after injection in the order: human>rabbit>rat, and haem uptake is consistently increased. For both rat and rabbit haemopexin saturation is reached at the same concentration of protein, i.e. 180-200pmol/g of liver, indicating that the different protein species bind to a common receptor. We propose that haemopexin transports haem to the liver by a specific receptor-mediated process and then returns to the circulation.     

A radioimmunoassay method for the rapid detection of Candida antibodies in experimental systemic candidiasis

Rabbits were employed as experimental models to evaluate a solid-phase radioimmunoassay (RIA) method for the diagnosis of systemic candidiasis. Ten rabbits were inoculated subcutaneously to mimic superficial candidiasis and were found to produce no antibodies to Candida as determined by both immunodiffusion and RIA procedures. However, 94 per cent of 18 rabbits systemically infected by intravenous injection of Candida cells were observed to produce antibody as assessed by the RIA technique. These data encourage further tests with human sera and the continued development of this RIA procedure as a useful tool in the early serodiagnosis of systemic candidiasis.     

In vitro development of theDrosophila chorion in a chemically defined organ culture medium

Summary TheDrosophila chorion is produced normally in isolated follicles in Robb's chemically defined culture medium. The complex architecture of the shell developed in vitro from follicles as young as early stage 10 is completely normal morphologically. In addition, the time required for in vitro development closely approximates that observed for in vivo development. Comparisons of insect culture media developed by Robb, Grace, Schneider, and Echalier show large variations in their ability to supportDrosophila chorion development.