Regulation of adenylate cyclase activity and stimulation response in relation to endometrial receptivity in the rabbit

Adenylate cyclase activity was measured in broken cell preparations of whole endometrial tissue from rabbits on Days 0, 1, 6.5, 9 and 15 of pseudopregnancy and in endometrial epithelial and stromal cells on Days 1 and 6.5 to assess the specific response of individual cell types. In dispersed cells, adenylate cyclase activity was higher (P less than 0.01) in stromal than in epithelial cells and reduced on Day 6.5 compared to Day 1 in both cell types. The response of adenylate cyclase to isoproterenol appeared more important relative to the PGE-2 response in epithelial than in stromal cells and strongly reduced in the former on Day 6.5. In endometrium, the overall adenylate cyclase activity was increased significantly on Day 1 of pseudopregnancy compared to Day 0 (oestrus), only 18 h after injection of hCG. On the following days, the activity decreased progressively on Days 6.5 and 9 and exhibited a recovery on Day 15. Adenylate cyclase response to isoproterenol (% over GTP) was comparable on Days 0, 1 and 6.5, abolished on Day 9 and recovered on Day 15. Maximal response to PGE-2 (% over GTP) was observed on Day 6.5, at the time of implantation, maintained on Day 9 and reduced on Day 15 towards the low levels measured in oestrus and Day 1 of pseudopregnancy. Our results demonstrate a dramatic alteration of adenylate cyclase activity in rabbit endometrium during pseudopregnancy. It suggests a possible involvement of catecholamines and prostaglandin E-2 in the regulation of endometrial receptivity through a cAMP-mediated process.     

Discrepancy between WISC-III and WISC-IV Cognitive Profile in Autism Spectrum: What Does It Reveal about Autistic Cognition?

The cognitive profile and measured intellectual level vary according to assessment tools in children on the autism spectrum, much more so than in typically developing children. The recent inclusion of intellectual functioning in the diagnostic process for autism spectrum disorders leads to the crucial question on how to assess intelligence in autism, especially as some tests and subtests seem more sensitive to certain neurodevelopmental conditions. Our first aim was to examine the cognitive profile on the current version of the most widely used test, the Wechsler Intelligence Scales for Children (WISC-IV), for a homogenous subgroup of children on the autism spectrum, i.e. corresponding to DSM-IV diagnosis of “autism”. The second aim was to compare cognitive profiles obtained on the third edition versus 4^th edition of WISC, in order to verify whether the WISC-IV yields a more distinctive cognitive profile in autistic children. The third aim was to examine the impact of the WISC-IV on the cognitive profile of another subgroup, children with Asperger’s Syndrome. 51 autistic, 15 Asperger and 42 typically developing children completed the WISC-IV and were individually matched to children who completed the WISC-III. Divergent WISC-IV profiles were observed despite no significant intelligence quotient difference between groups. Autistic children scored significantly higher on the Perceptual Reasoning Index than on the Verbal Comprehension Index, a discrepancy that nearly tripled in comparison to WISC-III results. Asperger children scored higher on the VCI than on other indexes, with the lowest score found on the Processing Speed Index. WISC-IV cognitive profiles were consistent with, but more pronounced than WISC-III profiles. Cognitive profiles are a valuable diagnostic tool for differential diagnosis, keeping in mind that children on the autism spectrum might be more sensitive to the choice of subtests used to assess intelligence.     

Effects of zinc on microalgal biofilms in intertidal and subtidal habitats

Microalgal biofilms are sensitive to environmental conditions. Impacts of contaminants on assemblages of marine biofilm are often investigated in laboratories or in mesocosms. Such experiments are rarely representative of the effects of contaminants on biofilms under natural conditions. Studies in field situations, with enough power to detect impacts, are necessary to develop a better understanding of the effects of contaminants on ecological processes. Metals are a common contaminant of marine systems and can cause disturbances to assemblages. Using a new technique to experimentally deliver contaminants to microalgal assemblages, hypotheses were tested regarding the effects of zinc on microalgal biofilms growing on settlement panels in subtidal and intertidal habitats. PAM fluorometry was used to assess the amount and physiological state of biofilms on panels. Control panels deployed for 1 month in each habitat had significantly greater amounts of biofilm than those exposed to zinc. After deployment for 3 months, the results varied with location. The observed effects on the biofilm did not, however, cause significant changes in the macro-invertebrate assemblages that developed on the panels.     

Effects of zinc on microalgal biofilms in intertidal and subtidal habitats

Microalgal biofilms are sensitive to environmental conditions. Impacts of contaminants on assemblages of marine biofilm are often investigated in laboratories or in mesocosms. Such experiments are rarely representative of the effects of contaminants on biofilms under natural conditions. Studies in field situations, with enough power to detect impacts, are necessary to develop a better understanding of the effects of contaminants on ecological processes. Metals are a common contaminant of marine systems and can cause disturbances to assemblages. Using a new technique to experimentally deliver contaminants to microalgal assemblages, hypotheses were tested regarding the effects of zinc on microalgal biofilms growing on settlement panels in subtidal and intertidal habitats. PAM fluorometry was used to assess the amount and physiological state of biofilms on panels. Control panels deployed for 1 month in each habitat had significantly greater amounts of biofilm than those exposed to zinc. After deployment for 3 months, the results varied with location. The observed effects on the biofilm did not, however, cause significant changes in the macro-invertebrate assemblages that developed on the panels.     

盖膜期间沙糖橘果实品质变化规律的研究

在果实成熟的1~3月,采样分析盖膜和不盖膜沙糖橘果实品质。结果表明:树冠盖膜后沙糖橘果皮色泽一直保持橘红色,而不盖膜的果皮色泽由前期的橘红色转为后期的橘黄色,且色泽暗淡;盖膜处理果实的酸含量在开始的20d内呈上升趋势,1月28日出现最高值0.31%,此后的10d内迅速下降至低于对照的水平,2月7日出现最低值,此后的20d内上升高于对照,之后又下降至3月15日的0.19%;对照果实的酸含量呈现明显的下降趋势,1月7日出现最高值为0.26%,3月15日出现最低值为0.08%,盖膜处理果实的酸含量在大多数时间内高于对照;盖膜处理果实的可溶性固形物含量从1月17日的12.33%提高到3月15日的13.40%,提高了1.07个百分点,总体呈上升趋势,而对照的从1月17日的10.70%下降至3月15日的9.90%,下降了0.80个百分点,总体呈下降趋势。     

Expression of the orexin system in the porcine uterus,conceptus and trophoblast during early pregnancy

Orexin A and B are hypothalamic peptides derived from the prepro-orexin (PPO) precursor. Orexins stimulate food intake and arousal. Those peptides bind and activate two G protein-coupled receptors: orexin receptor 1 (OX1R) and orexin receptor 2 (OX2R). Numerous authors have suggested that orexins play an important role in the regulation of the reproductive functions. The objective of the present study was to analyse the presence of and changes in the gene and protein expression pattern of the orexin system in the porcine uterus, conceptus and trophoblast (chorioallantois) during early pregnancy. In the endometrium, the highest PPO and OX1R gene expression was detected on days 15 to 16 of gestation. The OX2R mRNA content in the endometrium was higher on days 10 to 11 and 15 to 16 than on days 12 to 13 and 27 to 28. In the trophoblasts, PPO gene expression was higher on days 30 to 32 than on days 27 to 28. The highest PPO protein content in the endometrium was noted on days 12 to 13. The highest OX1R protein content in the endometrium was detected on days 10 to 11, whereas OX2R protein on days 15 to 16. In the trophoblasts, PPO and OX1R protein levels were more pronounced on days 27 to 28 than on days 30 to 32, but OX2R expression was higher on days 30 to 32. The expression of PPO, OX1R and OX2R was different in the conceptuses and trophoblasts during early pregnancy. Local orexin production and the presence of the specific orexin receptors suggest that the orexin system may participate in the control of porcine reproductive functions by exerting endocrine and auto/paracrine effects on the uterus, conceptuses and trophoblasts during early pregnancy. This study provides the first evidence for the presence of orexins and their receptors in the uteri, conceptuses and trophoblasts in pigs during early pregnancy. The local orexin system is dependent on the stage of pregnancy.     

Host plant-induced changes in detoxification enzymes and susceptibility to pesticides in the twospotted spider mite (Acari: Tetranychidae)

Adult female twospotted spider mites, Tetranychus urticae Koch, reared on lima bean plants were moved to cucumber, maize, or new lima bean plants (the latter being a control) and evaluated after 24 h or 7 d for changes in susceptibility to three pesticides and in levels of related detoxification enzymes. The largest and most consistent changes were observed in mites feeding on cucumber. Susceptibility of mites on cucumber to the synthetic pyrethroids bifenthrin and lambda-cyhalothrin was greater than that of mites reared on lima bean and maize after only 24 h on the plants, and remained higher after 7 d. Mites on cucumber also were more susceptible to the organophosphate dimethoate than were mites on lima bean, but only after 7 d on the host. Susceptibility was inversely related to activities of both general esterase and glutathione S-transferase (GST) in mites on cucumber; general esterase and GST activities were 60 and 25% lower, respectively, than activities of twospotted spider mite on lima bean after 7 d of feeding. Mites on maize were slightly but significantly more susceptible than those on lima bean to bifenthrin, but not to lambda-cyhalothrin, after 7 d and to dimethoate after 24 h but not after 7 d. General esterase and GST activities in twospotted spider mite fed on maize for 24 h were 20 and 16% higher, respectively, than activities in twospotted spider mite on lima bean, but general esterase activity was 30% lower than lima bean-fed mites and GST was not different after 7 d. Thus, plant-induced changes in general esterase activity, perhaps in combination with GST activity, in twospotted spider mite appear to be inversely related to, and possibly responsible for, changes in susceptibility of twospotted spider mite to several pesticides, particularly the synthetic pyrethroids. General esterases appear to play less of a role in the detoxification of the organophosphate insecticide dimethoate.     

The role of the aggregation of microbial cells in the development of salmonellosis in mice

The dependence of the invasive action of Salmonella typhimurium in mice on the aggregation of microbial cells has been studied in vivo, as well as in vitro on explanted intestinal tissue. The aggregation of salmonellae on kaolin grains has been found to lead to an increase in the level of adhesion of salmonellae to the intestinal mucosa of mice in vitro, to the accelerated course of infection in mice and their death and to the increased contamination of the spleen. The data obtained in these experiments age indicative of the possibility of the adverse influence of some sorbents on the course of the infectious process and confirm the concept advanced by the authors on the major importance of the surface concentration of salmonellae on the mucous membrane for the effectiveness of contamination.     

Roles of fimB and fimE in site-specific DNA inversion associated with phase variation of type 1 fimbriae in Escherichia coli.

Evidence obtained with an improved in vivo assay of fimbrial phase variation in Escherichia coli supported a revised understanding of the roles of fimB and fimE in the site-specific DNA rearrangement with which they are associated. A previously proposed model argued that fimB and fimE play antagonistic, unidirectional roles in regulating the orientation of the invertible DNA element located immediately upstream of fimA, the gene encoding the major subunit of type 1 fimbriae. This conclusion, though, is based on an in vivo DNA inversion assay using recombinant plasmid substrates under conditions that, among other things, were incapable of detecting recombination of the fim invertible element from the on to the off orientation. Using a modified system that overcome this and several additional technical problems, we confirmed that fimB acts independently of fimE on the invertible element and that the additional presence of fimE results in the preferential rearrangement of the element to the off orientation. It is now demonstrated that fimE can act in the absence of fimB in this recombination to promote inversion primarily from on to off. In contrast to the previous studies, the effect of fimB on a substrate carrying the invertible element in the on orientation could be examined. It was found that fimB mediates DNA inversion from on to off, as well as from off to on, and that, contrary to prior interpretations, the fimB-associated inversion occurs with only minimal orientational preference to the on phase.     

Increase in the activity of Rhizopus delemar lipase on water-soluble esters by its binding with phosphatidylcholine

Rhizopus (Rh.) delemar (ATCC 34612) C-lipase was found to exhibit a slight activity towards water-soluble esters. The hydrolytic reaction of this lipase on alpha-naphthyl acetate was competitively inhibited by the presence of olive oil or Tween 80. This finding showed that both substrates, insoluble triglyceride and water-soluble ester, were hydrolyzed at the same site on the enzyme. The activities on water-soluble esters (alpha-naphthyl acetate, beta-naphthyl acetate, methyl acetylsalicylate and Tween 80) increased on binding of lipase with phosphatidylcholine (PC), although the activity on olive oil did not change. The increase in activity on water-soluble esters was due to the increase in the Vmax for its hydrolysis. It appears that local structural change of the catalytic site on lipase occurred on binding of PC to the lipase molecule and resulted in an increase in the activity on water-soluble esters. The temperature dependence of the hydrolysis of water-soluble esters demonstrated that the activation energy was lowered on binding of PC to the lipase molecule, and this resulted in an increase in the activity.     

Demography of source—sink populations and the evolution of ecological niches

Summary The demography of populations living in variable environments is an important factor molding the evolution of ecological niches, for it determines the relative strength of selection pressures on adaptations to different habitats. Here I consider a coarse-grained environment consisting of two habitat types and investigate how the selection pressure on reproductive success in different habitats depends on their quality and frequency and the dispersal pattern. The results suggest that selection on adaptations to optimal habitats will usually be stronger than on adaptations to poor habitats and the ecological niche will thus tend to be an evolutionarily conservative character. It is because under the habitat choice or limited dispersal that seem to prevail in natural populations, more individuals encounter the better habitat than would be expected solely on the basis of its relative area. This bias results in reduced selection pressure on reproductive success in the poorer habitat. With habitat choice or limited dispersal, selection pressure on reproductive success in the poorer habitat may exceed that on reproductive success in the better habitat only if the poorer habitat is much more frequent in the environment than the better habitat and the difference in their quality is not large.     

Population biology of parasites of striped mullet, Mugil cephalus L. I. Monogenea

Young-of-the-year (class 0) and yearling (class 1) striped mullet, Mugil cephalus , were collected from Sapelo Island, Georgia from May 1970 to June 1971 to study the development, seasonal abundance and relationship of environmental variables to parasitic populations. The number of species of parasites increased with age of the host. Initial infection appeared to be influenced by closeness of association of mullet age classes, by the period of abundance of a parasite on class I mullet and by the mobility of the infective parasitic stage. Fluctuations in intensity and prevalence of a parasite on class 0 mullet were similar to those of class I mullet after the initial infection. Ancyrocephalus vanbenedenii was first observed on class 0 mullet in March. Intensity was high on both classes in spring and on reproductively active mullet in late autumn. Prevalence on both classes was above 80% except in late summer. Polyclithrum mugilis was not observed on class 0 mullet until August even though intensity and prevalence on class I mullet was highest during early spring. Gyrodactylus mugelus did not occur on class 0 mullet but appeared on class I mullet during late summer. Microcotyle psuedomugilis was observed on class 0 mullet in early summer and Metamicrocolyla maeracantha in October. Both species occurred but at a low intensity on class I mullet.     

长白山南坡苔原植被的特殊性及坡向间差异性分析

以长白山苔原带南坡植被为对象,通过植被调查,与北坡和西坡植被进行比较,研究长白山苔原植被因坡向差异导致的不同植被变化模式。结果显示:(1)长白山苔原南坡植被中灌木处于优势地位,与北坡、西坡情况一致。但在物种组成上,各坡向差异明显,为中度不相似水平;(2)在生物多样性、多度、盖度等群落特征上,南坡与西坡的差异较大、与北坡相似性较强;(3)在物种多样性的空间分布上,南坡与北坡相同,即随海拔升高呈单峰变化且峰值出现在中部,与西坡物种多样性随海拔升高呈单调递减的趋势完全不同。表明不同群落抗干扰能力以及所受干扰程度存在差异,北坡处于演替中后期,较为稳定,抗干扰能力更强。南坡因受干扰强度较小,植被处于较稳定状态;(4)长白山苔原各坡向植被变化差异较大。南坡和北坡的植被相对稳定,与西坡草本植物强烈上侵明显不同。长白山苔原带植被的坡向差异源于各坡向的本底差异、环境差异以及对全球气候变化的差异性响应,是火山、强风干扰下植被演替与响应气候变化的植被变化共同作用的结果。     

Resonance energy transfer between points in a reconstituted skeletal muscle thin filament. A conformational change of the thin filament in response to a change in Ca2+ concentration

The spatial relationships between Lys-61, Cys-374 on actin or SH1 on myosin subfragment-1 (S1) and Cys-190 on tropomyosin or Cys-133 on troponin-I (TnI) in a reconstituted thin filament were studied by fluorescence resonance energy transfer. 5-(2-Iodoacetylaminoethyl)aminonaphthalene 1-sulfonic acid (IAEDANS) attached to Lys-190 on tropomyosin or to Cys-133 on TnI was used as a donor. Fluorescein 5-isothiocyanate (FITC) attached to Lys-61 or 5-(iodoacetoamido)fluorescein (IAF) attached to Cys-374 on actin and 4-dimethylaminophenyl-azophenyl 4'-maleimide (DABMI) attached to SH1 on S1 were used as an acceptor. The transfer efficiency between AEDANS attached to Cys-190 on tropomyosin and FITC attached to Lys-61 on actin was 0.42 in the absence of troponin, 0.46 in the presence of troponin and Ca2+ and 0.55 in the presence of troponin and absence of Ca2+. The corresponding distances between the probes were calculated to be 4.7 nm, 4.6 nm and 4.3 nm respectively, assuming a random orientation factor K2 = 2/3. A large difference in the transfer efficiency from AEDANS attached to Cys-133 on TnI to FITC attached to Lys-61 on actin was observed between in the presence (0.52) and absence (0.70) of Ca2+. The corresponding distances between the probes were calculated to be 4.5 nm in the presence of Ca2+ and 3.9 nm in the absence of Ca2+. The distance between Cys-190 on tropomyosin and Cys-374 on actin was measured to be 5.1 nm and the transfer efficiency (0.35) did not change upon addition of troponin whether Ca2+ is present or not, in agreement with the previous report [Tao, T., Lamkin, M. & Lehrer, S. S. (1983) Biochemistry 22, 3059-3064]. The distance between Cys-133 on TnI and Cys-374 on actin was measured to be 4.4 nm. No detectable change in transfer efficiency (0.58) was observed between values in the presence and absence of Ca2+. These results suggest that a relative movement of the two domains of actin monomer in a reconstituted thin filament occurs in response to a change in Ca2+ concentration. The transfer efficiencies between DABMI attached to SH1 on S1 and AEDANS attached to Cys-190 on tropomyosin or Cys-133 on TnI were too small (less than 2%) for an accurate estimation of the distances, suggesting the distances are longer than 7.3 nm.     

Plant cues influence searching behaviour and parasitism in the egg parasitoid Trichogramma nr. brassicae

Abstract. 1. The effect of experience of plant cues at emergence on searching behaviour and parasitism was investigated in two strains of Trichogramma nr. brassicae (Hymenoptera: Trichogrammatidae).
2. Wasps reared on Sitotroga cereallela were allowed to emerge on a tomato plant or in a vial, with or without food. For one of the strains, females emerging on tomato searched significantly longer on a tomato seedling than females emerging in a vial.
3. The experience effect lasted between 1 and 2 days. It involves associating plant stimuli with the remains of the host, because females emerging from their host on a tomato plant had an increased searching response to tomato, but females transferred to the plant immediately after emergence did not.
4. The effect of emergence environment on parasitism of the host Helicoverpa punctigera on tomato and lettuce seedlings was tested. Wasps were allowed to emerge on seedlings of tomato or lettuce, or in an empty vial. For one strain, females experienced with tomato at emergence parasitized significantly more hosts on tomato than did females emerging on lettuce or in a vial. Parasitism on lettuce was not influenced by the treatments.     

Effect of Glutathione on Lipogenesis in Liver Slices from Rats Fed on Low Casein Diet

To study the mechanism of fatty infiltration in the liver due to added sulfur-containing amino acids to low casein diet, the effect of sulfur-containing amino acids and glutathione (GSH) on the incorporation of acetate-l-¹⁴C into lipid fractions were studied in liver slices from rats fed on 8% casein diet (Basal diet) with or without added methionine (Met).

The liver acetyl Co A carboxylase activities of rats on basal diet with or without added Met were similar.

Addition of Met, cystine or cysteine to the incubation medium had little effect on lipogenesis of slices. On addition of GSH to liver slices from rats fed on basal diet, lipid formation increased appreciably. On the other hand, addition of GSH to liver slices from rats fed on Met supplemented diet showed no accelerative effect on lipogenesis.

Addition of GSH to the incubation medium of liver slices from rats fed on basal diet tended to reduce the incorporation of acetate into the phospholipid fraction and to increase into the fatty acid fraction of liver slices.

The content of liver GSH was lower in rats on basal diet than in those on Met supplemented diet. The higher GSH level in rats on Met supplemented diet may be one factor causing fatty infiltration in the liver of these animals.     

The phenomenon of "one-trial tolerance" to the anxiolytic effect of chlordiazepoxide in the elevated plus-maze is abolished by the introduction of a motivational conflict situation.

A single exposure to the elevated plus-maze test of anxiety reduces or abolishes the anxiolytic efficacy of benzodiazepines. The present study was designed to examine whether this phenomenon of "one-trial tolerance" resulted from a motivational deficit on trial 2. We hypothesized that whereas there is a motivational conflict on trial 1 in relation to the open arms (exploration drive X natural fear of open spaces), there is no "reason" for an animal to explore it on trial 2. A motivational conflict was introduced on trial 2 by rendering the enclosed arms of the apparatus aversive on trial 1. Thus, every time rats entered the enclosed arms, an aversive situation (light and hot air blow) was produced until they left the arm. On trial 2, rats did not receive this aversive stimulation. Chlordiazepoxide significantly enhanced the percent open arm time as well as the percent open arm entries on trial 2 in rats that had been submitted to the aversive stimulation in the enclosed arms on trial 1, but was not effective in rats which had been exposed to the apparatus in the absence of the aversive stimulation on trial 1. In addition, there was no difference in the percent open arm time and entries on trial 2 between saline-treated rats submitted to the aversive or non-aversive condition on trial 1. The aversive condition on trial 1 did not modify the number of total arm entries on trial 2, either. The results suggest that the anxiolytic effect of chlordiazepoxide in the elevated plus-maze depends on the presence of a motivational conflict situation.     

鼠伤寒沙门菌pStSR100质粒对生物膜形成的影响

目的:鼠伤寒沙门菌在多种表面形成的生物膜对其致病性和引起食物中毒等方面起着重要作用,本研究探讨鼠伤寒沙门菌pStSR100质粒对细菌在不同材质表面生物膜形成的影响。方法:用LB(Luria-Bertani,LB)培养基和TSB(Tryptose Soya Broth,TSB)培养基分别将携带pStSR100质粒的野生株在96孔板与放置无菌小圆玻片的24孔板中静态培养48 h,用结晶紫半定量法确定生物膜形成的适宜培养基。将野生株与消除质粒的突变株,用结晶紫半定量法和激光共聚焦显微镜(Confocal Laser scanning microscopy,CLSM)观察其在聚苯乙烯培养板和小圆玻片表面形成生物膜的差异。结果:用LB培养时细菌生物膜的形成能力高于用TSB培养,LB培养基更适宜生物膜形成;结晶紫半定量法结果表明野生株比突变株在小圆玻片表面形成生物膜的能力明显增强,而在聚苯乙烯培养板表面两者则无明显差异;CLSM观察发现,野生株在小圆玻片表面形成融合成片的大克隆,突变株仅形成较小克隆。结论:鼠伤寒沙门菌pStSR100质粒能促进该菌在亲水性材质表面生物膜的形成,但其对该菌在疏水性材质表面生物膜的形成未见明显影响,这一新发现为进一步研究鼠伤寒沙门菌生物膜形成的调控机制,研制抗感染材料提供了理论和实验依据。