Effects of estrogen-depletion on rat casein gene expression

Mammary tissue from rats that had been ovariectomized and adrenalectomized 4 weeks previously was compared to that from intact rats in terms of epithelial content and hormone-responsiveness in vitro. The endocrinectomy resulted in about a 30% enlargement of the gland, but led to a loss of only about 12% of the epithelium. This estrogen-depleted epithelium was able to acquire full responsiveness in vitro to insulin in terms of the accumulation of alpha-aminoisobutyric acid, and induction of glucose-6-phosphate and gluconate-6-phosphate dehydrogenases. It was also fully responsive to cortisol in relation to the induction of NADH-cytochrome C reductase, and to prolactin in terms of total RNA synthesis. However, estrogen-depletion led to an 82% loss in the ability of a unit amount of the epithelium to synthesize casein in response to these 3 hormones, and to a similar loss in relation to the accumulation of 25K casein mRNA. Estrogen administration in vivo could prevent and reverse the casein lesion. The disparity between constitutive and casein hormone-responsiveness in the absence of estrogen is discussed in relation to cell commitment.     

HETEROCHRONIC DEVELOPMENTAL PLASTICITY IN LARVAL SEA URCHINS AND ITS IMPLICATIONS FOR EVOLUTION OF NONFEEDING LARVAE

Preexisting developmental plasticity in feeding larvae may contribute to the evolutionary transition from development with a feeding larva to nonfeeding larval development. Differences in timing of development of larval and juvenile structures (heterochronic shifts) and differences in the size of the larval body (shifts in allocation) were produced in sea urchin larvae exposed to different amounts of food in the laboratory and in the field. The changes in larval form in response to food appear to be adaptive, with increased allocation of growth to the larval apparatus for catching food when food is scarce and earlier allocation to juvenile structures when food is abundant. This phenotypic plasticity among full siblings is similar in direction to the heterochronic evolutionary changes in species that have greater nutrient reserves within the ova and do not depend on particulate planktonic food. This similarity suggests that developmental plasticity that is adaptive for feeding larvae also contributes to correlated and adaptive evolutionary changes in the transition to nonfeeding larval development. If endogenous food supplies have the same effect on morphogenesis as exogenous food supplies, then changes in genes that act during oogenesis to affect nutrient stores may be sufficient to produce correlated adaptive changes in larval development.     

Effect of heterosexual olfactory and visual stimulation on 5-en-3 beta-hydroxysteroids and progesterone in the male rat brain

Pregnenolone, dehydroepiandrosterone and progesterone were measured in specific areas of the brain and in the retina of young adult male rats exposed to the scent or to the scent and view of young cycling females and compared to the levels obtained in males similarly exposed to other males (control). All the steroid values observed were much higher than those found in plasma, varied considerably from one area to another and responded sometimes in opposite directions to stimulation of young adult males by the scent or by the scent and view of cycling females. In male rats exposed to the scent of young cycling females pregnenolone decreased significantly only in the olfactory bulb in comparison with the controls. There were no significant changes in dehydroepiandrosterone or progesterone in this case. When male rats were exposed to the scent and view of female rats, pregnenolone again decreased significantly in the olfactory bulb while dehydroepiandrosterone increased significantly in the olfactory bulb and the retina and progesterone decreased significantly in the hypothalamus, amygdala and parietal cortex. These results are discussed in relation with a possible new role for certain steroids in neuroregulatory mechanisms related to behaviour.     

Periodicity in the rise and fall of the numbers of the principal Staphylococcus aureus phage groups

The results of the phage typing of 5, 168 Staph. aureus strains isolated in a surgical hospital between 1959 and 1977 are analyzed for each year of this period. The wave of increase in the number of staphylococci belonging to phage group II which began, as discovered in this study, in 1965 and still showed no tendency towards decrease in 1977, as well as the periodicity of rises and falls in the number of staphylococci belonging to phage groups I and III are discussed and compared with the data contained in the literature. The authors come to the conclusion that Staph. aureus is subject to wave-like rises and falls in the number of strains belonging to the main phage groups of the species, and among them the strains belonging to phage groups I and III seem to be inversely related in respect of rises and falls in number, such changes occurring periodically at an interval of 10-12 years, while in the strains belonging to phage group II changes in number occur at a slower rate. The constant account of the percentage of phage groups I, II and III is recommended to ensure rational antibiotic therapy.     

Comparative ungulate dynamics: the devil is in the detail

Attempts to relate species differences in population dynamics to variation in life histories rely on the assumption that the causes of contrasts in demography are sufficiently simple to be derived from first principles. Here, we investigate the causes of contrasts in dynamics between two ungulate populations on Hebridean islands (red deer and Soay sheep) and show that differences in stability, as well as in the effects of variation in density and climate, are related to differences in timing of reproduction relative to seasonal variation in resource abundance. In both populations, attempts to predict changes in population size sufficiently accurately for the results to be useful for management purposes require a knowledge of the responses of different age and sex categories to changes in density and climate, as well as of population structure.     

Using genetically engineered mice for radiation research

The laboratory mouse has been used for many decades as a model system for radiation research. Recent advances in genetic engineering now allow scientists to delete genes in specific cell types at different stages of development. The ability to manipulate genes in the mouse with spatial and temporal control opens new opportunities to investigate the role of genes in regulating the response of normal tissues and tumors to radiation. Currently, we are using the Cre-loxP system to delete genes, such as p53, in a cell-type specific manner in mice to study mechanisms of acute radiation injury and late effects of radiation. Our results demonstrate that p53 is required in the gastrointestinal (GI) epithelium to prevent radiation-induced GI syndrome and in endothelial and/or hematopoietic cells to prevent late effects of radiation. We have also used these genetic tools to generate primary tumors in mice to study tumor response to radiation therapy. These advances in genetic engineering provide a powerful model system to dissect both the mechanisms of normal tissue injury after irradiation and the mechanisms by which radiation cures cancer.     

Respiration and microflora of the rhizosphere soil of wheat influenced by foliar application of urea

The numbers of micromycetes and bacteria were investigated with respect to oxygen consumption in the rhizosphere soil of wheat and in non-rhizosphere soil. Plants after foliar application of urea (2 % solution) and non-treated plants were cultivated in degraded chernozem and garden soil in a green-house. Changes in oxygen consumption by the suspensions of rhizosphere and non-rhizosphere soils corresponded to changes in the number of bacteria designated as the rhizosphere effect (R/S). Values of R/S depended on the presence of organic substrates. Changes in oxygen consumption by the soil suspension from the rhizosphere of wheat occurring due to foliar application of urea corresponded to changes in the amount of microflora. The results obtained are discussed with respect to a possible utilization of the data to follow metabolic activity of soils in a natural environment (in situ) determined according to oxygen consumption by a soil suspension, and to assess changes in the microflora of rhizosphere and non-rhizosphere soil.     

Sporophytic response to pollen selection for Alachlor tolerance in maize

In order to assess the efficiency of male gametophytic selection (MGS) for crop improvement, pollen selection for tolerance to herbicide was applied in maize. The experiment was designed to test the parallel reactivity to Alachlor of pollen and plants grown in controlled conditions or in the field, the response to pollen selection in the sporophytic progeny, the response to a second cycle of MGS, and the transmission of the selected trait to the following generations. The results demonstrated that pollen assay can be used to predict Alachlor tolerance under field conditions and to monitor the response to selection. A positive response to selection applied to pollen in the sporophytic progeny was obtained in diverse genetic backgrounds, indicating that the technique can be generally included in standard breeding programs; the analysis of the data produced in a second selection cycle indicated that the selected trait is maintained in the next generation.     

Novel Application of Confocal Laser Scanning Microscopy and 3D Volume Rendering toward Improving the Resolution of the Fossil Record of Charcoal

Variations in the abundance of fossil charcoals between rocks and sediments are assumed to reflect changes in fire activity in Earth’s past. These variations in fire activity are often considered to be in response to environmental, ecological or climatic changes. The role that fire plays in feedbacks to such changes is becoming increasingly important to understand and highlights the need to create robust estimates of variations in fossil charcoal abundance. The majority of charcoal based fire reconstructions quantify the abundance of charcoal particles and do not consider the changes in the morphology of the individual particles that may have occurred due to fragmentation as part of their transport history. We have developed a novel application of confocal laser scanning microscopy coupled to image processing that enables the 3-dimensional reconstruction of individual charcoal particles. This method is able to measure the volume of both microfossil and mesofossil charcoal particles and allows the abundance of charcoal in a sample to be expressed as total volume of charcoal. The method further measures particle surface area and shape allowing both relationships between different size and shape metrics to be analysed and full consideration of variations in particle size and size sorting between different samples to be studied. We believe application of this new imaging approach could allow significant improvement in our ability to estimate variations in past fire activity using fossil charcoals.     

Evaluating spatial within plot crop variability for different management practices with an optical sensor?

Subsoil constraints to root growth exacerbate frequent water and nutrient limitations to crop yields in Mediterranean-type environments. Amelioration of subsoil constraints can relieve these limitations by opening root-access to subsoil water and nutrients. However, decisions in subsoil amelioration are hampered by seasonally variable yield responses in these environments. We used the APSIM model to analyse the impact of subsoil constraints on yield and yield variability. The simulated yield data were used to calculate the financial benefits of subsoil amelioration across several scenarios. There was a strong yield-dependence on accessible soil water governed by root depth. Root depth development was limited to a minimum of either the effect of subsoil constraints or the weather-dependent depth of the soil wetting front. Insufficient rainfall in dry years or in a drier region often resulted in shallow soil wetting fronts and correspondingly shallow roots even in the absence of subsoil compaction. In these situations, there is little response to subsoil amelioration. Positive yield responses and positive financial returns to subsoil amelioration are therefore greater in good rainfall years and are more likely in a wetter region. A yield response to amelioration is also greater in coarser textured sand than finer textured sandy loam in an average rainfall season because the same amount of rainfall results in a deeper wetting front in sand than in sandy loam. Hence, roots in a sand are required to grow deeper compared to a sandy loam to access the same amount of water and therefore benefited more from subsoil amelioration in an average rainfall year. In wet years, sands leach more nitrate than sandy loam, which decreases yields and the response to subsoil amelioration in sands is more than in the sandy loam. Environmental threats occur along with yield loss when roots cannot access subsoil water. These include increased nitrate leaching and deep drainage due to unused water remaining in the soil profile. By allowing roots to access deep soil water, ameliorating subsoil is expected to yield financial gains in average to good rainfall seasons and decrease the environmental risk of drainage and leaching loss. The financial gains are expected to offset potential financial losses in dry and dry finish seasons especially in coarser textured soils and wetter environment. Responsible Editor: Jan Vos.     

Immunosenescence: potential causes and strategies for reversal

Age-related deterioration in immune function has been recognized in many species. In humans the clinical manifestation of such immune dysfunction is age-related increases in the susceptibility to certain infections and in the incidence of some autoimmune disease and certain cancers. Laboratory investigations reveal age-related changes in the peripheral T cell pool, in the predominant phenotype, cytokine production profiles, signalling function and in replicative ability following stimulus with antigen, mitogens or anti-CD3 antibody. These changes in the properties of peripheral T cells are thought to be causally linked to an age-associated involution in the thymus. Our analysis reveals that thymic involution is due to a change in the thymic microenvironment linked to a reduction in the level of available interleukin 7. Treatment with interleukin 7 leads to a reversal of thymic atrophy with increased thymopoiesis. This provides the potential to reverse the immune dysfunction seen in the peripheral T cell pool by replacing old cells with new output generated in the thymus. Problems to overcome in order for such an experimental therapy to be successful require careful analysis in order to provide an optimal strategy to ensure that new T cell emigrants from the thymus have a broad range of specificities and are able to enter the peripheral T cell pool.     

北戴河朱鹮野化种群非繁殖期日间活动时间分配和行为节律

于2019年7月-2020年1月对北戴河朱鹮野化种群非繁殖期的日间活动时间分配和行为节律进行了分析。结果表明,休息（41.8%）、觅食（39.7%）和理羽（13.3%）是北戴河朱鹮非繁殖期的主要行为。在行为节律上,有3个觅食高峰、2个休息高峰和2个理羽高峰。成鸟和幼鸟行为分配相似,但成鸟的警戒和社群等其他行为比例显著较高。与野生种群相比,北戴河野化种群的觅食时间显著较少,主要原因是野生个体需要花费较多时间搜寻食物,且飞行等活动的能耗较高。朱鹮在冬季的休息和理羽行为比例高于夏秋季,觅食行为则相反,这样可以在低温和大风天气降低能耗,是对北戴河气候环境的有效适应。为了提高朱鹮对多种气候环境的适应能力,为今后北戴河朱鹮的再引入奠定基础,我们建议在冬季要确保朱鹮有充足的适宜觅食地,同时在野化网笼中进行必要的环境丰容,如在网笼内增加常绿树种和阔叶树种,部分侧网上安装防风板,或在网笼中设置防风避寒的伞棚等设施,以供朱鹮进行选择。     

Cellular impact of combinations of endosulfan,atrazine, and chlorpyrifos on human primary hepatocytes and HepaRG cells after short and chronic exposures

Chronic exposure to low doses of pesticides present in the environment is increasingly suspected to cause major health issues to humans. Toxicological evaluations become more complex when the exposure concerns chemical combinations. Atrazine, chlorpyrifos, and endosulfan are pesticides used worldwide in agriculture and are therefore currently found at residual levels in food and the environment, even in countries in which they are now banned. Our study aimed to use Real-Time Cell Impedance Analyzer to investigate changes in phenotypical status of primary human hepatocytes and differentiated HepaRG cells induced by short and chronic exposures to these three chemicals. In contrast to the traditionally used endpoint cytotoxicity test, this technology allows kinetic measurements in real-time throughout the entire experiment. Our data show significantly higher cytotoxic effects of mixtures as compared to individual pesticides and a greater susceptibility of human hepatocytes as compared to HepaRG to short-term exposure (24 h). Repeated exposure over 2 weeks to endosulfan and endosulfan-containing mixture induced HepaRG cell death in a time- and dose-dependent manner. Of the typical genes involved in metabolism and cell-response to xenobiotics, we found an exposure time- and condition-dependent deregulation of the expression of CYP3A4 and UGT1A in HepaRG cells exposed to low doses of pesticides and mixtures. Our data demonstrate the usefulness of real-time cell monitoring in long-term toxicological evaluations of co-exposure to xenobiotics. In addition, they support but at the same time highlight certain limitations in the use of HepaRG cells as the gold standard liver cell model in toxicity studies.     

Natural variation in the V3 crown of human immunodeficiency virus type 1 affects replicative fitness and entry inhibitor sensitivity

Natural polymorphisms in the heterogeneous human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein may have an impact on both sensitivity to entry inhibitors and viral replicative fitness. Of significant interest is variation in the V3 crown due to its involvement in direct engagement with the coreceptor. Two positions in the crown (318 and 319) appear to be important in determining intrinsic susceptibility to multiple entry inhibitors. Thus, we evaluated a series of natural polymorphisms at positions 318 and 319 in three distinct CCR5-tropic envelope genetic backgrounds to address their role in replicative fitness and sensitivity to entry inhibitors. Change at position 319 to each of the three major consensus amino acids (A, T, and R) resulted in variation in sensitivity to entry inhibitors and altered replicative fitness, but the effects of any one amino acid depended on the envelope context. Change of the nearly invariant tyrosine at position 318 to a rare arginine resulted in increased sensitivity to entry inhibitors and decreased replicative fitness independent of envelope context. Polymorphisms in the V3 crown that showed increased susceptibility to entry inhibitors also exhibited decreased entry efficiency, replicative fitness in primary peripheral blood mononuclear cells, and ability to replicate in primary macrophages. These findings suggest that differences in coreceptor affinity and/or avidity may underlie these phenotypic characteristics.     

Brain vessels in the rats exposed to primary and repeated tail-suspension. Minimization of structural changes after repeated exposure

The aim of study was histological examination of brain vessels in the rats exposed to repeated tail-suspension (TS). The rats were subjected to 30-day TS, then readapted to horizontal position for 30 days and again exposed to 14-day TS simultaneously with the rats which were underwent to 14-day TS for the first time. 30-day TS induced in brain vessels the adaptive changes hindering the excessive blood inflow to brain--spasm and hypertrophy of muscle-elastic valves in extra- and intracerebral arteries and also the destructive changes--loss of vascular tone in extra- and intracerebral arteries, plethora in extra- and intracerebral veins, intracerebral venules and capillaries, conglutination of erythrocytes in capillaries, plasmatization of veins and capillaries and edema of brain tissue pointing out in total the increase in blood inflow to the brain and difficulty of blood outflow. After 30-day readaptation of TS-rats to horizontal position only adaptive changes in extracerebral arteries and intracerebral capillaries (cell proliferation) and edema of brain tissue were revealed. After repeated, 14-day TS in spite of new redistribution of blood to the head, in contrast to the vessel alterations after primary 14-day TS, the adaptive and destructive changes in brain vessels were lack, excluding only moderate plethora of intracerebral veins, cell proliferation in capillaries and weak signs of edema.     

A Three-Tiered Study of Differences in Murine Intrahost Immune Response to Multiple Pneumococcal Strains

We apply a previously developed 4-variable ordinary differential equation model of in-host immune response to pneumococcal pneumonia to study the variability of the immune response of MF1 mice and to explore bacteria-driven differences in disease progression and outcome. In particular, we study the immune response to D39 strain of bacteria missing portions of the pneumolysin protein controlling either the hemolytic activity or complement-activating activity, the response to D39 bacteria deficient in either neuraminidase A or B, and the differences in the response to D39 (serotype 2), 0100993 (serotype 3), and TIGR4 (serotype 4) bacteria. The model accurately reproduces infection kinetics in all cases and provides information about which mechanisms in the immune response have the greatest effect in each case. Results suggest that differences in the ability of bacteria to defeat immune response are primarily due to the ability of the bacteria to elude nonspecific clearance in the lung tissue as well as the ability to create damage to the lung epithelium.     

水稻品种对美国稻瘟病小种IB-33、IB-45和IE-1的抗性遗传

1995年10月至1997年11月,在美国阿肯色大学水稻研究推广中心,用水稻品种LA110和Jasmine-85与水稻品种Teqing、Katy、Mars、LaGrue和Newbonnet进行不完全双列杂交,对其杂交后代和亲本用美国3个主要稻瘟病菌小种(以下简称小种)IB-33、IB-45和IE-1进行接种鉴定和遗传分析研究.结果表明:亲本LA110、Jasmine-85、Teqing抗所有3个小种.Katy抗小种IB-45和IE-1,感小种IB-33.Mars抗小种IE-1,感小种IB-33和IB-45.LaGrue感所有3个小种.Newbonnet抗小种IB-45,感小种IB-33和IE-1.所有抗病亲本的抗病基因,其F1分别对相应小种呈现显性抗病性.抗病亲本杂交,LA110与Jasmine-85对小种IB-33,LA110与Teqing、Jasmine-85对小种IE-1,及Jasmine-85与Teqing对小种IE-1,是等位的抗病基因.LA110与Teqing对小种IB-33,及Jasmine-85与Teqing对小种IB-33,分别存在三对独立遗传的显性抗病基因.LA110与Teqing、Katy、Newbonnet、Jasmine-85对小种IB-45,Jasmine-85与Teqing、Katy、Newbonnet对小种IB-45,LA110与Katy、Mars对小种IE-1,Jasmine-85与Katy、Mars对小种IE-1,分别存在两对独立遗传的显性抗性基因.抗病亲本LA110或Jasmine-85与感病亲本Mars对小种IB-33,抗病亲本LA110与感病亲本Mars对小种IB-45,具有两对显性互补抗病基因,当两对显性抗病基因同时存在时,表现出抗性.抗病亲本LA110或Jasmine-85与感病亲本Katy、LaGrue、Newbonnet对小种IB-33,抗病亲本LA110与感病亲本LaGrue对小种IB-45,抗病亲本Jasmine-85与感病亲本Mars、LaGrue对小种IB-45,抗病亲本LA110或Jasmine-85与感病亲本LaGrue、Newbonnet对小种IE-1,分别存在一对显性抗病基因.两个亲本正、反交的遗传表现一致.本文也讨论了LA110、Teqing和Jasmine-85三个抗病品种在美国水稻抗病育种中利用的可能性.     

Hoop Housing for Feeder Pigs Offers a Welfare-Friendly Environment Compared to a Nonbedded Confinement System

Total confinement systems of swine production offer several benefits and costs in terms of animal welfare. Swine raised in total confinement are protected from environmental extremes and predators; however, welfare concerns stem from observations of stereotypic behavior and lameness of pigs, common in some of these systems. Because total confinement systems are expensive to build and maintain compared to less intensive systems, producers have become interested in an inexpensive alternative: hoop structures (Hoop). Open-ended Quonsets shaped like a half cylinder lying on its flat side, the Hoop use bedding to keep the pigs dry and allow this bedding to compost beneath the pigs to keep them warm in winter. This project compared the behavior and physiology of pigs in a nonbedded confinement system (NBCS) with those in the Hoop. Two experiments, 1 in the winter and 1 in the summer, assessed the welfare of pigs based on the incidence of aberrant behavior, physiologic response to handling, incidence of lameness, and the performance of play behavior. Pigs raised in the NBCS performed more aberrant behaviors and less play behavior, had greater plasma cortisol in response to handling (but fewer vocalizations), and a greater incidence of injuries than did the pigs raised in the Hoop. Based on these data, pigs in the Hoop were adjudged to have enhanced welfare as compared to pigs raised in the NBCS. Because the welfare of pigs in the Hoop appears to be greater than the welfare of pigs raised in the NBCS, future research should determine which factors are most important to pigs and then try to incorporate these into production systems.     

Strategies adopted by the mudskipper Boleophthalmus boddaerti to survive sulfide exposure in normoxia or hypoxia

The effects of sulfide on the energy metabolism of Boleophthalmus boddaerti in normoxia and hypoxia were examined. The 24-, 48-, and 96-h LC50 values of sulfide for B. boddaerti with body weight ranging from 11.6 to 14.2 g were 0.786, 0.567, and 0.467 mM, respectively. The tolerance of B. boddaerti to sulfide was not due to the presence of a sulfide-insensitive cytochrome c oxidase. There was no accumulation of lactate in the muscle and liver of specimens exposed to sulfide in normoxia. In addition, the levels of ATP, AMP, and energy charge in both the muscle and the liver were unaffected. These results indicate that B. boddaerti was able to sustain the energy supply required for its metabolic needs via mainly aerobic respiration when exposed to sulfide (up to 0.4 mM) in normoxia. Exposure of B. boddaerti simultaneously to hypoxia and 0.2 mM sulfide for 48 h resulted in decreases in the ATP levels in the muscle and liver. However, the energy charge in both tissues remained unchanged, and the level of lactate accumulated in the muscle was too low to have any major contribution to the energy budget of the fish. Our results reveal that B. boddaerti possesses inducible mechanisms to detoxify sulfide in an ample supply or a lack of O2. In normoxia, it detoxified sulfide to sulfate, sulfite, and thiosulfate. There were significant increases in the activities of sulfide oxidase in the muscle and liver of specimens exposed to sulfide, with that in the liver being >13-fold higher than that in the muscle. However, in hypoxia, sulfide oxidase activity in the liver was suppressed in response to environmental sulfide. In such conditions, there were significant increases in the activities of sulfane sulfur-forming enzyme(s) in the muscle and liver that were not observed in specimens exposed to sulfide in normoxia. Correspondingly, there were no changes in the levels of sulfate or sulfite in the muscle or liver. Instead, B. boddaerti detoxified sulfide mainly to sulfane sulfur in hypoxia. In conclusion, B. boddaerti was able to activate different mechanisms to detoxify sulfide, producing different types of detoxification products in normoxia and hypoxia.