Effects of lead on hepatocyte ultrastructure in Carassius carassius (L.) var. auratus

Subcellular modifications in hepatocytes of Carassius carassius var. auratus subjected to 24 hr and 48 hr sublethal acute lead (5mg·1⁻¹) exposure were studied by electron microscopy. Cytological alterations were observed after 24 hr of treatment and became more evident after 48 hr. Lead induced an increase in nuclear heterochromatin and alterations in mitochondria, endoplasmic reticulum and Golgi complex ultrastructure. Glycogen granula decreased, and secondary lysosomes and lipid droplets increased. Furthermore, intracytoplasmic lumina with microvilli-bearing surfaces and numerous autophagic vacuola were observed after 48 hr of exposure.     

The effect of time on physiological changes in eel Anguilla anguilla, induced by lindane.

1. Eel were exposed to a sublethal concentration of lindane (0.335 ppm) for 6, 12, 24, 48, 72 and 96 hr. 2. Concentrations of glycogen, glucose, lactate, pyruvate and lipids were determined in gill tissue after lindane exposure. 3. Gill glycogen decreased and glucose levels increased at 6 hr of treatment, lactate and pyruvate concentration increased between 6 and 48 hr. Total lipid values decreased between 6 and 24 hr; thereafter, the levels increased up to 72 hr of exposure. 4. Clear changes were found in all parameters tested in gill tissues. The observed effects of lindane on metabolism in fish are discussed in relation to acute stress syndrome.     

Expression of heat shock protein 70 in freshwater prawn Macrobrachium malcolmsonii (H. Milne Edwards) following exposure to Hg and Cu

Juveniles of freshwater prawn M. malcolmsonii were exposed to 1/6th concentration of LC50 of Hg and Cu for 48 hr. Sampling was done at 1 8, 12, 16, 24, 30, 36, 42 and 48 hr of exposure. Gill and hepatopancreas were dissected and subjected to one-dimensional electrophoresis. Western blotting was employed to determine the relative concentration of heat shock protein, hsp 70 (stress-70) in each sample. In the gill tissue of the prawn that had been exposed to Hg (0.024 mgHg 1(-1)), stress-70 was detected from the 1st hr till the 16th hr of exposure. But in the gills of Cu exposed prawn, synthesis of stress-70 appeared from the 1st hr till the 24th hr. Synthesis of hsp70 was not recorded after the 24th hr in the gills of exposed prawns. Synthesis of stress-70 was also found to be tissue-specific for both metals in this prawn. When the antibody probe raised against stress-70 was used, synthesis of stress-70 was not observed in hepatopancreas of prawns exposed to Hg or Cu, during the entire period of exposure of 48 hr. The expression of stress-70 in M. malcolmsonii following exposure to Hg and Cu is apparently only transient, and also a differential expression of stress-70 between gill and hepatopancreas was observed for both the metals.     

Studies on chilling injury in plant cells I. Ultrastructural changes associated with chilling injury in callus tissues of Cornus stolonifera

This study was designed to elucidate the primary ultrastructuralchanges associated with chilling injury of cultured cells ofCornus stolonifera (TK-1). The cultured cells suffered seriousinjury after exposure to 0?C for longer than 24 hr, while noinjury was observed with less than 12 hr of treatment. Earlyultrastructural responses to chilling treatment were detectedin proplastids and the rough endoplasmic reticulum within 12hr of treatment. A remarkable ultrastructural change in thetonoplast, i.e., invagination, infolding and partial disruption,became apparent in the 24-hr stage of chilling treatment. Novisible change, however, was observed in mitochondria, nucleiand plasma membranes within 24 hr. Upon exposure to 0?C for48 hr, an abrupt degradation proceeded in the cytoplasm. Thesequential ultrastructural changes observed in cell organdies,especially proplastids, rough endoplasmic reticulum and thetonoplast, were closely related to the degradation of the cellscaused by chilling treatment. ¹ Contribution No. 1840 from the Institute of Low TemperatureScience, Hokkaido University. ² This work was supported in part by Grant 248004 from the Ministryof Education. (Received September 8, 1977; )     

Estrogen and progesterone interactions influencing sexual and social behavior in the brown lemming, Lemmus trimucronatus.

The effects of estrogen and progesterone on the social and sexual behavior of brown lemmings, Lemmus trimucronatus, were investigated. The behavior of hormone-treated and untreated ovariectomized females and sexually vigorous males was observed in six consecutive daily 5-min dyadic encounters. Sexual receptivity, as measured by lordosis, and other social behaviors including nasonasal contact, boxing postures, allogrooming, perineal investigation, and male mounting increased following 48 hr of exposure to daily injections of 0.5 μg estradiol benzoate (EB). Lordosis in EB-primed females was not facilitated or inhibited by short-term (4 hr) exposure to 0.5 mg progesterone (P). Long-term (greater than 24 hr) exposure to P apparently inhibited lordosis and other social behaviors in EB-treated females, although males continued to attempt to mount these females. In EB-treated females a dramatic increase in threat-leaps, directed by the female toward the male, was observed within 4 hr of P injection. Threat-leaps declined when P was withdrawn. Threat-leaps were also observed in ovariectomized females after prolonged exposure to P only (0.5 mg/day). Vaginal perforation and cornification were first apparent 48 hr after EB injection. P-alone treated ovariectomized females also showed vaginal perforation but cornified cells were infrequent and these animals did not show lordosis.     

Effects of 60Co radiation on synthesis of prostaglandins F2 alpha, E, and thromboxane B2 in lung airways of guinea pigs

At 1 hr to 14 days after total-body exposure of guinea pigs to 3.0 Gy 60Co, changes were detected in prostaglandin concentrations in bronchial airway tissues. At 3 hr postexposure, tissue levels of PGE were significantly elevated, while at 48 hr transiently elevated levels of PGF2 alpha were observed. By 72 hr, levels returned to control values. Airway synthesis of thromboxane B2 in irradiated animals did not differ from that in controls. Also assessed were the capacities of bronchial airway preparations to respond to H-1 receptor stimulation by the exogenous addition of histamine or transmembrane divalent cation transport stimulation with ionophore. Tissues from irradiated animals demonstrated alterations in the amount and type of prostaglandins generated, varying with time postirradiation.     

Acute toxicity and bioaccumulation of endosulfan in rotifer (Brachionus calyciflorus).

1. The acute toxicity of endosulfan was determined for the freshwater rotifer Brachionus calyciflorus. 2. The mean 24 hr LC50 value for endosulfan was 5.15 ppm with a coefficient of variation of 14.7%. 3. Rotifers were exposed at two sublethal concentrations (1.5-2.0 ppm) of endosulfan for bioaccumulation experiments, for an exposure time of 24, 48, 72 and 96 hr. The rotifers were fed with Nannochloris oculata (5 x 10(5) cell/ml). 4. The highest accumulation of endosulfan was found 24 hr after the start of the exposure to 1.5 ppm of the toxicant. A steady-state concentration in rotifer was reached between 24-48 hr, followed by a gradual decrease until 96 hr.     

In vivo adaptive control of beta-receptors and adenylate cyclase during short-term heat exposure in rat parotid glands.

1. Adaptation of beta-adrenergic receptors (beta-AR) and adenylate cyclase (AC) in rat parotid glands during short-term heat exposure (33 degrees C) were studied. 2. Heat exposure reduced AC activity in response to isoproterenol (IPR). 3. The number of beta-AR on the cell surface significantly increased after 24 hr but returned to control level after 48 hr. 4. IPR-induced [3H]GDP release was significantly reduced throughout exposure. 5. The data suggest that the major factor which results in the desensitization of AC during short-term heat exposure is a blunted coupling between beta-AR and GTP binding protein(s).     

EARLY EVENTS IN LYMPHOCYTE TRANSFORMATION BY PHYTOHEMAGGLUTININ : I. DNA-Dependent RNA Polymerase Activities in Isolated Lymphocyte Nuclei

The DNA-dependent RNA polymerase activities of isolated nuclei from lymphocytes were examined after stimulation with phytohemagglutinin (PHA). The nuclear fraction was prepared with Mg⁺⁺ or Mn⁺⁺ to distinguish between polymerase I (nucleolar) and polymerase II (nucleoplasmic). Distinction between polymerases II and III was obtained by the addition of α-amanitin to the reaction mixture. The results indicated that within 15 min after exposure to PHA the activity of polymerase I increased. Polymerase II activity increased after 1 hr. The enhancement was linear for 6 hr and then leveled off for the subsequent 48 hr. Small increase in polymerase III activity was observed at 48 hr. Inhibition of protein synthesis at the time of exposure to PHA did not prevent the increase in activities during the initial 6 hr. These results imply that the initial increase in enzymatic activities is dependent upon preexisting polymerase molecules and/or factors.     

Toxic effects of zinc and iron on the routine oxygen consumption of Tilapia sparrmanii (Cichlidae)

1. The routine oxygen consumption of Tilapia sparrmanii without the addition of any toxicants over a 72 hr period showed a decrease for the first 48 hr, but stabilised thereafter.2. Addition of zinc (98 mg l⁻¹) resulted in a drastic decrease of oxygen consumption for 3 hr. The routine oxygen consumption showed a significant decrease for the first 24 hr, while the second and third 24 hr revealed significant differences with great individual variance.3. The decrease in oxygen consumption observed after exposure to zinc, could be caused by gill damage as well as the internal action of zinc.4. An increase in oxygen consumption was noted for almost 3 hr after addition of iron (88mg l⁻¹). During the first-, second- and third 24 hr the oxygen consumption increased significantly, compared to the control values.5. The increase in routine oxygen consumption of T. sparrmanii when compared to control values after exposure to iron, could be attributed to stress and possible gill changes.6. The study revealed that after acute (72 hr) exposure to sublethal concentrations of zinc and iron, the routine oxygen consumption of T. sparrmanii was altered.     

Effects of storage and incubation conditions on human granulocyte phagocytic, bactericidal, and chemotactic functions

This study was undertaken to determine the effects of different incubation conditions on human granulocyte (PMN) bactericidal, phagocytic, and chemotactic functions. Specifically, (1) how long may a patient's blood be held before assay and maintain original PMN function, and (2) how long may isolated PMNs be incubated for the purpose of exposure to various agents and still maintain original function? PMNs isolated following storage of whole heparinized blood at 4 °C for 24 and 48 hr phagocytized as well as fresh cells and their bactericidal activity was 96 and 85% of control values after 24 and 48 hr, respectively. Chemotaxis decreased to 62% of control after 24 hr. The bactericidal capacity of isolated PMNs stored at 4 °C for 24, 48, and 72 hr decreased to 85, 81, and 78% of controls, respectively. Phagocytosis after 24 hr storage was equal to controls. Chemotaxis was decreased to 59 and 34% of controls after 24 and 48 hr, respectively. Isolated PMNs incubated at 37 °C demonstrated impairment in phagocytic capacity after only 4 hr.     

The effect of time on physiological changes in eel Anguilla anguilla,induced by lindane

• 1.1. Eel were exposed to a sublethal concentration of lindane (0.335 ppm) for 6, 12, 24, 48, 72 and 96 hr.
• 2.2. Concentrations of glycogen, glucose, lactate, pyruvate and lipids were determined in gill tissue after lindane exposure.
• 3.3. Gill glycogen descreased and glucose levels increased at 6 hr of treatment, lactate and pyruvate concentration increased between 6 and 48 hr. Total lipid values decreased between 6 and 24 hr; thereafter, the levels increased up to 72 hr of exposure.
• 4.4. Clear changes were found in all parameters tested in gill tissues. The observed effects of lindane on metabolism in fish are discussed in relation to acute stress syndrome.

     

Temporal effects of estrogen and progesterone on behavioral and endocrinological responses to acute cocaine administration.

Estrogen and progesterone have been postulated to play a key role modulating cocaine-induced behavioral and neurochemical activation in female rats. This study investigated the temporal relationship between estrogen and progesterone in the modulation of cocaine-induced behavioral alterations. Ovariectomized Fischer rats received s.c. injections of estradiol benzoate 48 hr prior to cocaine or saline treatment and one s.c. injection of progesterone concurrently or 1, 4, 20, 24, 30, 44 or 48 hr after estrogen treatment. Forty-eight hours after estrogen treatment rats received either a single i.p. injection of 15 mg/kg of cocaine or 0.9% saline. Overall, cocaine induced increases in locomotor behaviors (ambulatory and rearing activity). A bimodal interaction between estrogen and progesterone was observed in the modulation of all locomotor activities. A gradual increase in behaviors, which peaked when progesterone was administered 24 hr after estrogen was followed by an inhibition of both ambulatory and rearing activity when progesterone was administered for a shorter period of time. This estrogen and progesterone interaction was not observed in the modulation of cocaine-induced stereotypic activity. However, shorter administration of progesterone in relation to estrogen administration resulted in lowered benzoylecgonine plasma levels when compared to longer progesterone administration times. On the other hand, longer administration of progesterone (48 hr of estrogen and progesterone) caused increases in corticosterone levels in cocaine-treated rats. Thus, the temporal interaction between estrogen and progesterone in the regulation of cocaine metabolism and hypothalamic-pituitary-axis (HPA) activation do not completely correlate with that observed for locomotor behavioral activation. Taken together, these results suggest that temporal interactions between estrogen and progesterone may underlie some of the previously reported estrous cycle and sex effects on cocaine-induced behavioral and endocrinological alteration.     

Organophosphorus diazinon induced toxicity in the fish anguilla angvilla L.

1. Acute toxicity effects of diazinon on European eel (Anguilla anguilla) were examined using short-term exposures in static conditions.2. The lc₅₀ values found were: 0.16, 0.11, 0.09 and 0.08 mg/1 at 24, 48, 72 and 96 hr exposure, respectively.3. Eels were exposed to 0.056 mg/l of diazinon and the bioaccumulation and elimination of this insecticide in liver, muscle, gill and blood tissues were studied.4. BCF were 800 in liver, 1600 in muscle tissue and 2300 and 2730 in gill and blood tissue, respectively.5. The BCF₁ were 0.30 for liver, 0.60 for muscle and 0.84 for gill. Higher accumulation capacity of the gill was observed for the first hour of exposure.6. Diazinon elimination from the selected tissues was rapid, diazinon levels were not detected in any tissue after 24 hr in clean water.7. The excretion rate constants (K₂) of this insecticide were 0.023 hr⁻¹ for liver, 0.005 hr⁻¹ for gill and 0.019 ⁻¹ for muscle.8. Diazinon half-lives were calculated as 30.6, 32.2 and 38.3 hr for liver, muscle and gill, respectively.     

Exposure of pulmonary artery endothelial cells to nitrogen dioxide activates phospholipase A1

Phospholipase A1, A2, and C and diacylglycerol lipase activities were measured in cell sonicates after exposing confluent monolayers of porcine pulmonary artery endothelial cells to 5 ppm NO2, a toxic constituent of environmental pollution, for 24 and 48 hr. There was a significant increase (2.25-fold) in phospholipase A1 activity in 24 and 48 hr NO2-exposed cells, whereas activities of phospholipases A2 and C and diacylglycerol lipase were comparable to control cells at both time points. When endothelial cells were prelabeled with [3H]-arachidonic acid and then exposed to NO2 for 48 hr, increased counts were recovered from cell lysophospholipids with concomitant decreased recovery of counts from cell phosphatidylcholine and phosphatidylethanolamine. These results demonstrate that NO2 exposure results in specific activation of phospholipase A1.     

Ultrastructural study of early development of Nosema algerae in Anopheles albimanus

Early development of Nosema algerae in Anopheles albimanus was studied by electron microscopy. Sporoplasms were observed in the thorax and first three abdominal segments at 1 hr after initial exposure. The first division occurred between 30 and 36 hr. Immature spores were present at 48 hr with mature spores observed at 54 hr. By 60 hr from initial exposure, some of the mature spores had extruded and sporoplasms were seen. By 96 hr, all stages were present and development was no longer synchronous.     

Cellular responses in the skin of the gilthead sea bream Sparus aurata L. and the sea bass Dicentrarchus labrax (L.) exposed to high ammonia

Adult gilthead sea bream Sparus aurata and sea bass Dicentrarchus labrax were exposed for 24 and 48 h, respectively, to two concentrations of ammonia each (mean values of 3·34 and 13·10 mg l(-1) TA-N in S. aurata; 2·99 and 11·90 mg l(-1) TA-N in D. labrax). Light microscopy and computerized morphometry were used to evaluate ammonia-induced alterations in skin structure during exposure and following recovery in normal water. In S. aurata, ammonia exposure induced a concentration-dependent increase in the number (hyperplasia) of neutral mucous cells (mc), with peak values at 24 h recovery after exposure. An increase in the dispersion of melanosomes in skin melanocytes was also observed in the dermis and occasionally in the epidermis of S. aurata, with peak values at 24 h of ammonia exposure. Exposure of D. labrax to ammonia had, likewise, concentration-dependent effects on mucous secretion. Of the two types of mc in this species, there was an increase in the number of the neutral mc and a reduction in the much more numerous acid mc, with peak values at 24 and 48 h, respectively, of ammonia exposure. The more intense mucous secretion in D. labrax compared to S. aurata could be related to the lower tolerance to ammonia in D. labrax, as reported elsewhere. Finally, the increase in melanosome dispersion was less evident in D. labrax, due to highly variable control values. These morphological alterations to the skin could be useful indicators of non-specific stress in cultured fishes.     

The effects of nerve growth factor and dibutyryl cyclic AMP on cytoskeletal densities in cultured sensory ganglia.

The effects of nerve growth factor (NGF) and dibutyryl cyclic AMP (DBC) on the density of cytoskeletal structures in cultured dorsal root ganglia were examined using morphometric techniques. After 24 hr in culture, NGF-treated neurites were longer than either DBC-treated or control neurites. At 48 hr, neurites produced in response to NGF and DBC were of equivalent length, while controls were considerably shorter. Comparison of electron micrographs of neuritic profiles revealed some differences of area and cytoskeletal density between treatment groups. Morphometric analysis was used to determine these differences under several growth conditions, at various rates of elongation and at different neurite lengths. As shown by analysis of variance, both NGF-treated and control neurites tapered in diameter at 48 hr in vitro, while DBC-induced neurites increased in area. An increase in cytoskeletal density for all treatment groups indicated that density was not always correlated with changes in area. An increased density of microtubules as compared to neurofilaments was seen at 24 hr, with equal densities of both cytoskeletal elements present after 48 hr in vitro. Comparisons between individual groups of data indicated that NGF-treated neurites relied primarily on microtubular density at 24 hr in vitro, when NGF induced longer, faster growing neurites. At 48 hr, there was an increase in neurofilaments proximal to the explant in the presence of DBC, implying that DBC may cause increased synthesis and/or transport of these structures. A comparison of microtubule to neurofilament ratios indicated that at 24 hr, there was always a greater density of microtubules. However, after 48 hr, neurofilament density increased such that there were equivalent densities of both cytoskeletal elements, possibly due to the overall increase in length observed in each treatment group. These data imply that 1) neurites with different rates of elongation may exhibit differences in cytoskeletal density; 2) neurites of equivalent lengths may be of differing stabilities; 3) NGF and DBC produce neurites with different cytoskeletal densities, implying divergent mechanisms of neurite induction; 4) the presence or absence of NGF may be partially responsible for variations in cytoskeletal densities observed between peripheral and central processes of DRG during development.     

Disruption of circulatory and respiratory activity in shore crabs (Carcinus maenas (L)) exposed to heavy metal pollution

Cardiac and respiratory activity of the shore crab, Carcinus maenas (L.), were disrupted following exposure to heavy metal ions. Exposure to 3 mg l-1 copper ions induced continuous, uninterrupted heart beat in quiescent, undisturbed crabs. Copper ions (10 mg l-1) suppressed cardiac activity and oxygen consumption within 2 hr. Alternating periods of bradycardia and tachycardia were observed together with marked changes in impedance cardiograph trace height. Similar, but more pronounced changes were seen following exposure to 1 mg l-1 mercury ions. Median perfusion index was 100 ml blood ml O2(-1) (range 58-114 ml blood ml O2(-1)) prior to pollution, but increased to peak values within the range 90-220 ml O2(-1) following exposure to copper or mercury. The effects of exposure to copper were transient and largely reversible. Exposure to mercury resulted in 100% mortality 24-48 hr after initial contamination. Death was apparently associated with loss of the osmoregulatory ability of these crabs.     

Expression of the MDR-1 gene-encoded P-glycoprotein in cardiomyocytes of conscious sheep undergoing acute myocardial ischemia followed by reperfusion.

We have recently reported that in chronic myocardial ischemia, adult mammalian cardiomyocytes express P-glycoprotein (P-gp). We now investigate if P-gp is also expressed in acute regional ischemia followed by reperfusion. Adult conscious sheep underwent 12-min occlusion of the mid-left anterior descending artery (inflatable cuff). Successful ischemia-reperfusion was confirmed by monitoring percent systolic left ventricular anterior wall thickening (sonomicrometry) during the whole ischemic period and every 10 min over 2 hr following cuff deflation. At 3, 24, and 48 hr after reperfusion, P-gp expression was investigated by immunohistochemistry and Western blot and MDR-1 mRNA by RT-PCR. Cardiomyocytes in the occluded artery territory (but not those in remote areas) consistently expressed P-gp at their sarcolemma. Whereas at 3 and 24 hr P-gp was mainly observed in the T tubules, at 48 hr it predominated in intercalated discs and gap junctions. RT-PCR and Western blot revealed higher expression in ischemic than in control myocardium. We conclude that in adult sheep with acute myocardial ischemia, the MDR-1 gene-encoded P-gp is expressed at the sarcolemma of the cardiomyocytes from 3 hr up to at least 48 hr after reperfusion.