Perinatal iron deficiency affects locomotor behavior and water maze performance in adult male and female rats

Iron deficiency during early growth and development adversely affects multiple facets of cognition and behavior in adult rats. The purpose of this study was to assess the nature of the learning and locomotor behavioral deficits observed in male and female rats in the absence of depressed brain iron levels at the time of testing. Adult female Wistar rats were fed either an iron-enriched diet (>225 mg/kg Fe) or an iron-restricted diet (3 mg/kg Fe) for 2 wk prior to and throughout gestation, and a nonpurified diet (270 mg/kg Fe) thereafter. Open-field (OF) and Morris water maze (MWM) testing began when the offspring reached early adulthood (12 wk). At birth, perinatal iron-deficient (PID) offspring had reduced (P < 0.001) hematocrits (-33%), liver iron stores (-83%), and brain iron concentrations (-38%) compared with controls. Although there were no differences in iron status in adults, the PID males and females exhibited reduced OF exploratory behavior, albeit only PID males had an aversion to the center of the apparatus (2.5 vs. 6.9% in controls, P < 0.001). Additionally, PID males required greater path lengths to reach the hidden platform in the MWM, had reduced spatial bias for the target quadrant, and had a tendency for greater thigmotactic behavior in the probe trials (16.5 vs. 13.0% in controls; P = 0.06). PID females had slower swim speeds in all testing phases (-6.2%; P < 0.001). These results suggest that PID has detrimental programming effects in both male and female rats, although the behaviors suggest different mechanisms may be involved in each sex.     

Effects of ozone on evaporative water loss and thermoregulatory behavior of marine toads (Bufo marinus).

Ozone (O(3)) is a strong pulmonary irritant and causes a suite of respiratory tract inflammatory responses in humans and other mammals. In addition to lung injury, rodents exposed to O(3) exhibit a pronounced decrease in core body temperature at rest, which may offer a protective effect against O(3) damage. The effects of O(3) on other vertebrates have not been studied. Compared to individuals exposed to air (N=34), Bufo marinus toads exposed to O(3) (N=32) for 4 h lost 3.78 g body mass (adjusted mean from analysis of covariance, body mass mean+/-SD, 90.1+/-21.90 g). We tested the thermoregulatory responses of 22 toads in a thermal gradient 1, 24, and 48 h after 4-h exposure to air (N=11) or 0.8 ppm O(3) (N=11). Individual toad thermal preferences were also significantly repeatable across all trials (intraclass correlation=0.66, P <0.001). We did not observe a direct effect of O(3) exposure on the preferred body temperatures (PBT) of toads. However, O(3) exposure did have an indirect effect on selected temperatures. Ozone-exposed toads with higher evaporative water loss rates, in turn, also selected lower PBT, voluntary minimum, and voluntary maximum temperatures 24 h post-exposure. Ozone exposure may thus alter both water balance and thermal preferences in anuran amphibians.     

Effects of ozone exposure on nonspecific phagocytic capacity of pulmonary macrophages from an amphibian, Bufo marinus

Pulmonary macrophages are an important component of immune defense against inhaled foreign particles and microorganisms. In humans and other mammals, exposure to moderate amounts of ozone (O3) can inhibit functional capacities of alveolar macrophages. In many wilderness areas downwind of urban centers, ozone levels frequently exceed national standards. We report results of 4-h inhalation exposures to 0.8 parts per million O3 on pulmonary macrophage viability and phagocytosis capacity in marine toads, Bufo marinus. At 1 and 24 h after ozone exposure, macrophages had reduced in vitro capacity to phagocytize fluorescent polystyrene microspheres. By 48 h postexposure, there were no differences in these macrophage functions between ozone- and air-exposed toads. Macrophage yield did not differ among exposure groups nor did exposure to elevated temperatures (30 degrees C) for up to 48 h affect recovery of macrophages. However, compared with the millions of macrophages per milliliter recovered in mammals by similar procedures, pulmonary macrophage yield was typically in the range of 50 to 200 x 10(3) per milliliter extracted fluid. These results are the first to report effects of an air pollutant on amphibian immune system function and suggest a possible role of oxidant air pollutants in regional declines of amphibian populations.     

Agriculture Alters Gonadal Form and Function in the Toad Bufo marinus

Background

Many agricultural contaminants disrupt endocrine systems of wildlife. However, evidence of endocrine disruption in wild amphibians living in agricultural areas has been controversial. Typically, studies on the effects of pollutants on wildlife attempt to compare polluted with unpolluted sites.

Objectives

We took a novel approach to address this question by explicitly quantifying the relationship between gonadal abnormalities and habitats characterized by differing degrees of agricultural activity.

Methods

We quantified the occurrence of gonadal abnormalities and measures of gonadal function in at least 20 giant toads (Bufo marinus) from each of five sites that occur along a gradient of increasing agricultural land use from 0 to 97%.

Results

The number of abnormalities and frequency of intersex gonads increased with agriculture in a dose-dependent fashion. These gonadal abnormalities were associated with altered gonadal function. Testosterone, but not 17β-estradiol, concentrations were altered and secondary sexual traits were either feminized (increased skin mottling) or demasculinized (reduced forearm width and nuptial pad number) in intersex toads. Based on the end points we examined, female morphology and physiology did not differ across sites. However, males from agricultural areas had hormone concentrations and secondary sexual traits that were intermediate between intersex toads and non-agricultural male toads. Skin coloration at the most agricultural site was not sexually dimorphic; males had female coloration.

Conclusions

Steroid hormone concentrations and secondary sexual traits correlate with reproductive activity and success, so affected toads likely have reduced reproductive success. These reproductive abnormalities could certainly contribute to amphibian population declines occurring in areas exposed to agricultural contaminants.     

Optimisation of handling, activation and assessment procedures for Bufo marinus spermatozoa

In the present study, we investigated handling, activation and assessment procedures for cane toad (Bufo marinus) spermatozoa. Optimisation of these techniques will facilitate the maintenance of sperm viability during cryopreservation and during in vitro fertilisation (IVF) techniques in reproduction technologies for endangered species. Spermatozoa were taken from testicular macerates and assessed using plasma membrane integrity assays (live/dead stains) and quantitative scores of motility parameters. In the assessment of sperm viability using live/dead stains, there were small but significant differences in the percentage of sperm from cryopreserved samples staining positive with propidium iodide, Hoechst H33258 and Trypan blue; these differences were not large and all stains performed acceptably. Spermatozoa were activated by dilution of testicular macerates in water at one of two dilution ratios (1 : 6 or 1 : 20) with or without 0.1-5.0 mM theophylline. Sperm plasma membrane integrity (unstained spermatozoa) was unaffected by either dilution ratio (osmolarity) or theophylline concentration. However, sperm motility was significantly affected by osmolarity and theophylline concentration. The stimulation of sperm motility increased with higher theophylline concentrations and these strongly interacted with lower osmolarities through a higher dilution ratio of sperm macerates with water. Spermatozoa were exposed to increasing centrifugation forces to determine tolerance to physical stresses encountered during washing procedures. Forces between 50 and 800 g were associated with a significant reduction in motility (mean 56 +/- 3% decreasing to 27 +/- 3%), but did not affect staining. In conclusion, centrifugation should be minimised in anuran sperm washing procedures; osmotic shock associated with higher dilution ratios reduces the capacity of anuran sperm to achieve high percentages of motile sperm, leading to a likely trade-off between dilution required for activation and sperm motility to optimise IVF fertilisation rates; and optimal conditions for sperm motility after activation occur at lower dilutions of suspensions with 5.0 mM theophylline. The present study has improved protocols for the handling of anuran sperm during pre- and post-cryopreservation procedures.     

Postnatal lead exposure affects motor skills and exploratory behavior in rats.

The present study was undertaken to investigate the behavioral effects of postnatal lead exposure. Newborn male Sprague-Dawley rats were given 1 or 8 mg/kg lead acetate intraperitoneally daily for 20 days. Control rats received 1 mg/kg sodium acetate, or 8 mg/kg sodium acetate in oversized litters. The high dose lead acetate group and the high dose, oversized sodium acetate group showed impaired weight and length increment during the end of the treatment. Rats treated with the higher dose of lead showed delayed eye opening. The time required to turn in a negative geotaxis test was transiently longer in rats treated with the higher dose of lead. A tendency of reduced forepaw grasping ability was seen in lead-treated rats during the end of the lead exposure. Ambulation and rearing in an open field were lower for the rats treated with the higher dose of lead acetate during certain periods of development. Impaired performance in a balancing rod test was also seen in the rats treated with the higher dose of lead at the adult stage, while no difference was seen in ambulation or gnawing activity during tail pinch-induced stress. Thus, lead intoxication in rats during the early postnatal period, with doses that approximate those in children, induced transient as well as persistent dysfunctions in exploratory behavior and motor skills. These observed actions of lead may be related to impaired maturation of sensitive brain regions which develop postnatally.     

Daphnia magna feeding behavior after exposure to tetradifon and recovery from intoxication.

The feeding behavior of the cladocera Daphnia magna subjected to a short-term exposure to the acaricide tetradifon (4-chlorophenyl 2,4, 5-trichlorophenyl sulfone) was studied. The experiments were performed using the unicellular algae Nannochloris oculata at a density of 5x10(5) cells/ml as food for the organisms. In a first experiment, three generations (F0, F1, and F3) of the daphnids were exposed to sublethal levels of tetradifon (0.1, 0.18, 0.22, and 0.44 mg/l) and the effect of the toxicant on filtration and ingestion rates was determined. Rates of filtration and ingestion of D. magna declined in the three generations studied with increasing toxicant concentrations; however, toxicant effect was greater in daphnids from generations F1 and F3 than in those from the parental generation F0. A second experiment was conducted in order to evaluate whether animals of a first (1) or third (F3) generation coming from parental daphnids (F0) previously exposed to those pesticide concentrations exhibited any alteration in feeding behavior when transferred to clean water (recovery period). The results indicated that the feeding rates of D. magna generations F1 and F3 were still affected during the recovery period but to a less degree. The effective tetradifon concentrations D. magna at which feeding rates were reduced to 50% that of controls (EC(50)) were also calculated.     

Acute exposure to DE-71: Effects on locomotor behavior and developmental neurotoxicity in zebrafish larvae

The aim of the present study was to investigate the acute developmental neurotoxicity of polybrominated diphenyl ethers (PBDEs) in zebrafish larvae. From 2 to 120?h postfertilization zebrafish embryos were exposed to DE-71 (0, 31.0, 68.7, and 227.6?μg/L). The authors studied the locomotor behavior of larvae, involvement of the cholinergic system, and selected gene and protein expressions in the central nervous system. The results showed that low DE-71 concentration caused hyperactivity, whereas higher concentrations decreased activity during the dark period. During the light period, larval activity was significantly reduced in a concentration-dependent manner. In the cholinergic system, acetylcholinesterase activity significantly increased (10.7 and 12.4%) in the 68.7 and 227.6?μg/L exposure groups, respectively, and acetylcholine concentration accordingly decreased (60.5%) in the 227.6?μg/L exposure group. The mRNA expressions of genes encoding myelin basic protein, neuron microtubule protein (α1-tubulin), and sonic hedgehog a were significantly downregulated. Western blotting assay demonstrated that the protein concentration of α1-tubulin was also decreased. Overall, the present study demonstrated that acute exposure to PBDEs can disrupt the neurobehavior of zebrafish larvae and affect cholinergic neurotransmission and neuron development. Environ. Toxicol. Chem. 2012; 31: 2338-2344. ? 2012 SETAC.     

Prenatal exposure to diethylstilbestrol (DES): Childhood play behavior and adult gender-role behavior in women

Data from lower mammals suggest a masculinizing or defeminizing influence of pre- or perinatal diethylstilbestrol (DES) exposure on various aspects of the sex-dimorphic behavior (including juvenile rough-and-tumble play) of genetic females. However, three previous studies on childhood play and adult gender-role behavior in human females have led to ambiguous results. In a follow-up study of 60 women with prenatal exposure to DES and 26 controls, we used psychometrically well-designed multi-item scales based on self-report inventories for the assessment of these aspects of behavior. No effects of DES could be demonstrated. We conclude that, at the doses studied, prenatal DES exposure in human females has not led to behavioral masculinization or defeminization of childhood play and adult gender-role behavior.This research was supported in part by U.S. Public Health Service research grants MH-34635 (NIMH), MH-30906 (NIMH), and MH-43878 (NIMH). Dr. Lish was supported in part by U.S. Public Health Service training grant MH-18264 (NIMH).     

Sexual behavior and impregnation success of adult male mosquitofish following exposure to 17beta-estradiol

The effects of 17beta-estradiol (E2) on the sexual activity of adult male mosquitofish (Gambusia holbrooki) were assessed. Sexually mature males were exposed to nominal concentrations of 20, 100, and 500 ng/L of E2 and a solvent control (0.00001% ethanol v/v) for 84 days under continuous flow conditions. Following exposure, males exposed to E2 at concentrations of 20 ng/L and above displayed a lower level of sexual activity, measured as the number of approaches and copulation attempts made toward nonexposed females, than the control males. In addition, E2-exposed males were less capable of impregnating females than the control males. Exposure to E2 had no significant effect on spermatozeugmata production or the secondary sexual characteristics, indicating that the reduced impregnation efficiency of the E2-exposed males was most likely due to the decline in sexual activity.     

Storage of cane toad (Bufo marinus) sperm for 6 days at 0 degrees C with subsequent cryopreservation

We investigated the recovery of motility of cane toad (Bufo marinus) sperm after storage for 6 days at 0 degree C (on ice) and after subsequent cryopreservation. Sperm suspensions were prepared from testes macerated in either simplified amphibian Ringer (SAR) or 10% (w/v) sucrose diluents, with 15% or 20% (v/v) glycerol or Me2SO as cryoprotectants, and were stored for 6 days. Alternatively, suspensions were prepared in either SAR or 10% (w/v) sucrose diluent and stored for 6 days, after which some of these suspensions were kept in diluents alone or, alternatively, had 15% or 20% (v/v) glycerol or Me2SO added. All treatments (suspensions) were then cryopreserved. Sperm motility was measured at Day 1 and Day 6 (before and after cryopreservation). A substantial and variable proportion (range 0%-40%) of sperm was immotile in suspensions immediately after preparation from testes macerates. Sperm stored in either SAR or 10% (w/v) sucrose diluent maintained approximately 75% motility for 6 days, but few sperm survived cryopreservation. After storage and cryopreservation, recovery of motility was substantially higher with Me2SO than in glycerol. However, both cryoprotectants exhibited toxicity at high concentrations. Glycerol was more toxic than Me2SO in 10% (w/v) sucrose than in SAR diluent, both before and after cryopreservation. The addition of some cryoprotectants to suspensions before storage gave greater recovery both before and after cryopreservation. After cryopreservation, the highest rate of sperm recovery was in suspensions with 10% (w/v) sucrose and 15% (v/v) Me2SO added prior to storage (mean (+/-SEM) 46 +/- 7% relative to initial; 39 +/- 6% absolute). Sperm were also stored for 6 days at 0 degrees C in suspensions or testes (with suspensions then prepared from testes) and cryopreserved. Sperm maintained higher recovery and membrane integrity both before and after cryopreservation when stored in suspensions rather than in testes.     

1～3岁婴幼儿进食行为调查

目的:了解1~3岁婴幼儿奶瓶和杯的使用情况及相关因素,探讨目前饮食行为中存在的问题以及相关的干预措施。方法:采用自制的进食行为调查表调查1~3岁婴幼儿奶瓶和杯的使用情况及相关因素。结果:1~3岁婴幼儿使用奶瓶相当普遍,学习用杯的技能并没有在适当的年龄得到训练,带养者还存在很多认识误区。结论:1~3岁婴幼儿缺乏足够多的机会学习,从杯中饮的进食能力的发育还没有受到家长及儿童保健医生的重视,应在适当的年龄训练婴幼儿的进食技能。     

Sex difference in operant behavior following single exposure to carbon monoxide in adult rats

Sex difference of effects of single exposure of carbon monoxide (CO) on operant behavior was studied in adult rats. The animals were obtained by continued selective breeding and have a high level of avoidance ability and small individual differences (THA rat: Tokai high avoider rat). Experiments were conducted as follows: Exposure were carried out at the concentrations of 50, 100, 200 and 400 ppm of CO gas for 4 h in THA rats, and their operant behavior was studied by Sidman avoidance test conducted 1 h before and after CO exposure. Rats whose carboxyhemoglobin (COHb) in blood was determined after the termination of CO exposure were of the same strain and age as those that underwent operant behavior test. Exposure of CO 50 ppm did not produce any marked change in operant behavior. In male rat groups, response counts in the Sidman avoidance test decreased after exposure to CO 100, 200 and 400 ppm when compared to the value before exposure, but increase in shock counts was observed only by exposure to CO 400 ppm. In female rat groups, response counts decreased after the exposure to CO 200 and 400 ppm, but shock counts did not show any marked change at all the CO exposure concentrations. COHb concentrations immediately after the exposure to CO 50, 100, 200 and 400 ppm for 4 h were 9.1 +/- 1.2, 13.5 +/- 0.5, 24.3 +/- 0.7 and 43.6 +/- 1.6%, respectively, in males, and 9.2 +/- 1.1, 13.7 +/- +/- 0.8, 24.0 +/- 1.0 and 42.0 +/- 1.4%, respectively, in females.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of fetal exposure to gamma rays on aggressive behavior in adult male mice.

Aggressive behavior (AB) in first generation (F1) hybrid male C57BL/6xC3H mice irradiated on the 14th day of gestation was studied at 100-135 days of age. Gravid female mice were irradiated with 1.0 or 2.0 Gy of gamma rays to the whole body. The AB of pairs of mice were recorded with a capacitance-induction motility monitor and on videotape. Recordings were continued for 90 min, starting at 2:00 PM. Vigorous wrestling, boxing and biting were regarded as AB. Data recorded at 15-min intervals were stored on micro-computer discs. The body weight for the irradiated group was significantly lower than that for the control group. The number of instances of AB was significantly higher in the irradiated group. The AB of the 2.0 Gy group was significantly more intensive than that of the control group. No difference in the duration of AB was found for the 2 irradiated and the control groups. Results demonstrate that male mice irradiated prenatally show increased aggressiveness.