Synthetic peptide KKRR corresponding to the human ACTH fragment 15–18 is an antagonist of the ACTH receptor

Tritium-labeled synthetic fragments of human adrenocorticotropic hormone (ACTH) [³H]ACTH (11–24) and [³H]ACTH (15–18) with a specific activity of 22 and 26 Ci/mmol, respectively, were obtained. It was found that [³H]ACTH-(11–24) binds to membranes of the rat adrenal cortex with high affinity and high specificity (K _d 1.8 ± 0.1 nM). Twenty nine fragments of ACTH (11–24) were synthesized, and their ability to inhibit the specific binding of [³H]ACTH (11–24) to adrenocortical membranes was investigated. The shortest active peptide was found to be an ACTH fragment (15–18) (KKRR) (K _i 2.3 ± 0.2 nM), whose [³H] labeled derivative binds to rat adrenocortical membranes (K _d 2.1 ± 0.1 nM) with a high affinity. The specific binding of [³H]ACTH-(15–18) was inhibited by 100% by unlabeled ACTH (11–24) (K _i 2.0 ± 0.1 nM). ACTH (15–18) in the concentration range of 1–1000 nM did not affect the adenylate cyclase activity of adrenocortical membranes and, therefore, is an antagonist of the ACTH receptor.     

Responsiveness of the interrenal tissue of Jundiá (Rhamdia quelen) to an in vivo ACTH test following acute exposure to sublethal concentrations of agrichemicals

As in many aquatic environments, pollution is a widespread problem in Southern Brazil. In our previous work, we demonstrated that sublethal contamination with some agrichemicals impairs the capacity of fishes to elevate cortisol levels in response to an additional acute stressor. In earlier experiments, the experimental design did not allow us to conclude where this effect occurs. In the present work, we used the adrenocorticotropic hormone (ACTH) challenge test to help us identify if the impairment occur in the interrenal tissue. For this purpose, five experiments were conducted, each with one specific agrichemical (methyl-parathion, atrazine+simazine, atrazine, tebuconazole, and glyphosate) in sublethal concentrations of 16.6% of the LC(50-96h), as previously determined. Fish were subjected to the ACTH challenge test protocol as follows: group 1, were non-injected and maintained as the specific control group; group 2 received an injection of the vehicle alone (the saline group); and group 3 receive an injection of ACTH. One hour later, blood samples were taken from the caudal plexus, using sterile syringes. In all specific control groups, the injection of ACTH induced a strong rise in plasma cortisol, compared with the fish injected only with the vehicle and the non-injected group. Fish exposed to methyl-parathion and tebuconazole did not elevate cortisol in response to the ACTH injection, with values significantly lower than the control fish. Fish exposed to sublethal concentrations of atrazine+simazine, atrazine, and glyphosate showed a rise in plasma cortisol very similar to the control fish. We conclude that the ACTH challenge test revealed that R. quelen exposed to sublethal concentrations of tebuconazole and methyl-parathion had a reduced ability to elevate plasma cortisol in response to an intraperitoneal (i.p.) injection of exogenous ACTH, indicating that the interrenal tissue is the site of the impairment within the HPI axis. These ACTH challenge tests also revealed that the impairment of the cortisol response verified in fish exposed to atrazine+simazine and glyphosate, as shown in our previous work, seems to be related to steps of cortisol secretion in higher levels within the HPI axis.     

Learning and memory processes of an ACTH4–9 analog (ebiratide; Hoe 427) in mice and rats

These experiments investigated the effects of the new ACTH_4–9 analog ebiratide (Hoe 427) [H-Met(O₂)-Glu-His-Phe-D-Lys-Phe-NH-(CH₂)₈-NH₂×3 CH₃COOH] on memory processes in mice and rats in five training tasks. With all five training and testing procedures (inhibitory avoidance test with ECS- or scopolamine-induced amnesia, up-hill avoidance, one-way shuttle box avoidance and eight-arm radial maze) ebiratide was most effective in a dose range of 1–10 μg/kg SC.     

Synthetic ACTH-Like Peptide GKVLKKRR,Corresponding to the Fragment 81–88 of Human Pro-Interleukin-1α, Acts as an Antagonist of ACTH Receptor

Synthetic adrenocorticotropic hormone (ACTH)-like octapeptide leukocorticotropin (GKVLKKRR), corresponding to the amino acid sequence 81–88 of pro-interleukin-1α, was labeled with tritium (specific activity of 22 Ci/mmol) and was found to bind to rat adrenal cortex membranes with high affinity and specificity (K _d = 2.2 ± 0.1 nM). Synthetic ¹²⁵I-labeled ACTH fragment 11–24 was also obtained (specific activity of 98 Ci/mmol) and shown to bind to ACTH receptor on rat adrenal cortex with high affinity (K _d = 1.8 ± 0.1 nM). Unlabeled leukocorticotropin was found to actively replace ¹²⁵I-labeled ACTH (11–24) in the receptor-ligand complex (K _i = 2.0 ± 0.1 nM). Leukocorticotropin at concentration range of 1–1000 nМ did not affect the adenylate cyclase activity in adrenocortical membranes. Thus, leukocorticotropin is an antagonist of ACTH receptor. ACTH-like peptide GKVLKKRR is an antagonist of ACTH This work financeed by the Russian Foundation for Basic Research (grant No. 05-04-48060), by the programs Leading Scientific Schools (grant No. 312.2003.4), Molecular and Cellular Biology (chairman V.M. Lipkin), and Naukogrady (grant No. 04-04-97200), and by the International Science and Technology Center (project No. 2615). V.V. Yurovsky is supported by the American Heart Association (grant No. 0555415U).     

What changed the demography of an introduced population of an herbivorous lady beetle?

1. The population dynamics of an introduced population of Epilachna niponica (Lewis) (Coleoptera: Coccinellidae) was investigated for a 7-year period following its introduction to a site outside of its natural range. A population from Asiu Experimental Forest was introduced to Kyoto University Botanical Garden, 10 km south of its natural distribution.
2. Arthropod predation was much lower in the introduced than in the source population. As a result of the lower predation in the Botanical Garden, larvae reached densities five times higher than in the Asiu Forest and host plants were frequently defoliated. Food shortage caused larval deaths from starvation and increased dispersal.
3. The density of the introduced population was much more variable than that of the source population. The variation in population density in both the introduced and source populations is limited by density-dependent reduction in fecundity and female survival. However, variation in the introduced population's density was increased due to host plant defoliation that resulted in overcompensating density-dependent mortality. In years with high larval density plants were defoliated and this increased adult mortality during the prehibernation period. Besides, the density-dependent regulatory mechanisms that produce population stability were weaker in the introduced population than in the source population.     

Gibberellin: inhibitor of an inhibitor of...?

Gibberellin is an endogenous plant growth regulator. Here, we describe our present understanding of how gibberellin regulates plant growth, using recent results gained from studies of gibberellin-signalling mutants of Arabidopsis. These results show that a signalling pathway represses plant growth and that gibberellin releases this repression. In consequence, the well-known growth-promoting properties of gibberellin are due to its activity as an "inhibitor of an inhibitor" [Brian Pw. Sym Soc. Exp Bio 1957; 11:166-182 (Ref. 1)] of plant growth.     

中枢ACTH受体研究进展

除垂体以外,中枢神经系统也含有促肾上腺皮质激素（ＡＣＴＨ）能神经元,其神经纤维在中枢具有较广泛的投射。ＡＣＴＨ相关肽类在中枢发挥着多种生理功能。近年来对于中枢ＡＣＴＨ受体的研究取得很大的进展,现已确认ＡＣＴＨ结合位点在中枢具有广泛的分布。新近克隆出的四种ＡＣＴＨ受体中,有两种是中枢神经系统占优势的受体亚型。     

Differential subcellular localization of ACTH and α-MSH in corticotropes of the rat anterior pituitary

Summary Specific antisera to -melanotropin (-MSH) and corticotropin (ACTH 1-39) were used to obtain immunocytochemical evidence for the differential localization of -MSH and ACTH in the secretory granules of corticotropes of rat anterior pituitary. The specificity of the antisera was established by binding ¹³¹I-labeled -MSH and ACTH 1-39 to their respective antisera. Double-labeling immunocytochemistry (for -MSH, ferritin; for ACTH, colloidal gold) was performed. Some secretory granules were labeled with ferritin particles (-MSH), whereas others contained gold particles (ACTH). Only a few granules showed both ACTH and -MSH. In typical corticotropes (stellate in form with a small number of secretory granules aligned along the cell periphery) only some of the secretory granules that were labeled with anti-ACTH serum were also immunoreactive to anti--MSH. In atypical corticotropes (polygonal in shape and containing a large number of secretory granules) almost all of the immunoreactive ACTH secretory granules were also positive to anti--MSH serum. An intermediate type of corticotrope was observed containing a small number of secretory granules, almost all of which were labeled with anti--MSH. Thus, rat anterior pituitary corticotropes may be classified into three types according to the distribution and content of -MSH. The light-microscopic immuncytochemistry provided similar results.     

Stimulation of ACTH release by naloxone: Central or peripheral action?

The concentration of ACTH and corticosterone in plasma were measured following peripheral administration of naloxone and naloxone methylbromide (quaternary derivative of opiate antagonist naloxone which is thought not to cross the blood brain barrier) in male rats. Subcutaneous administration of naloxone methylbromide in the dose range of 0.625 - 5.0 mg kg-1 resulted in a small but significant increase in plasma corticosterone levels. Both naloxone and its quaternary derivative injected via permanent intraperitoneal catheters to freely moving rats induced a highly significant increase in plasma ACTH levels measured in blood obtained via permanent tail artery catheters 30 min following injection. These results indicate that loci outside the blood brain barrier are, at least partially, involved in the naloxone-induced stimulation of ACTH release.     

Identification of an aminothiazole series of RORβ modulators

Crystallography has identified stearic acid, ALRT 1550 and ATRA as ligands that bind RORβ, however, none of these molecules represent good starting points to develop optimized small molecule modulators. Recently, Compound 1 was identified as a potent dual RORβ and RORγ inverse agonist with no activity towards RORα (Fig. 1). To our knowledge, this is one of only two small molecule RORβ inverse agonists identified in the primary literature from a tractable chemical series and represents an ideal starting point from which to design RORβ-selective modulators. Herein we describe our SAR optimization efforts that led to a series of potent neutral antagonists of RORβ.     

Non-canonical autophagy: an exception or an underestimated form of autophagy?

Macroautophagy (hereafter called autophagy) is a dynamic and evolutionarily conserved process used to sequester and degrade cytoplasm and entire organelles in a sequestering vesicle with a double membrane, known as the autophagosome, which ultimately fuses with a lysosome to degrade its autophagic cargo. Recently, we have unraveled two distinct forms of autophagy in cancer cells, which we term canonical and non-canonical autophagy. In contrast to classical or canonical autophagy, non-canonical autophagy is a process that does not require the entire set of autophagy-related (Atg) proteins in particular Beclin 1, to form the autophagosome. Non-canonical autophagy is therefore not blocked by the knockdown of Beclin 1 or of its binding partner hVps34. Moreover overexpression of Bcl-2, which is known to block canonical starvation-induced autophagy by binding to Beclin 1, is unable to reverse the non-canonical autophagy triggered by the polyphenol resveratrol in the breast cancer MCF-7 cell line. In MCF-7 cells, at least, non-canonical autophagy is involved in the caspase-independent cell death induced by resveratrol.     

Economics of wildlife management—an overview

This study makes an explorative overview on two main research topics in economics of wildlife management: determination of population sizes and policy design. The results point out a large and comprehensive research on each of these issues, in particular on the estimation of values and costs of wildlife, where this information is necessary for the determination of population size. A drawback is that most of the value and cost studies do not relate their estimates to wildlife population size, which limits their usability for efficient policy design. Most valuation studies estimate the recreational value of hunting, which can range between 13 and 545 USD/hunting day (in 2013 prices), and two thirds of the included studies have been applied to wildlife in the USA. A majority of the studies on the costs of wildlife management calculate losses from carnivore predation on livestock and ungulate damage to crops, while a few consider dispersal of diseases and the cost of traffic collisions. Unlike valuation studies, several of the cost estimates apply to wildlife in developing and emerging economies. With respect to policy design the literature, which is mainly theoretical, suggests economic incentives for conflict resolution, where those suffering from wildlife damages are compensated for their losses. However, there are some issues which remain to be addressed by economists: relating costs and benefits to wildlife populations; estimating values and costs of wildlife in developing countries; evaluating wildlife policies in practice; addressing implications of uncertainty in population size, costs, and benefits for policy design; and estimating transaction costs for implementation and enforcement of wildlife policies.     

Stacking behavior of an intertidal abalone: an adaptive response or a consequence of space limitation?

Intertidal populations of black abalone Haliotis cracherodii Leach at Santa Cruz Island, California, vary in density among surge channels from < 1 to 126 abalone/m². Dense populations are characterized by high levels of intraspecific secondary substratum use (“stacking”) for attachment surfaces, though it is rare in low density areas. Use of shell surfaces by black abalone appears not to be an evolved adaptive strategy. Individuals in stacks fed significantly more than expected, yet solitary abalone next to stacks shared food trapped by stacks. In the laboratory, starvation did not increase the propensity of an abalone to stack. Stacks were equally common in the breeding and non-breeding seasons, suggesting that stacking behavior was not a mechanism to enhance reproductive success. Stacking did not enhance avoidance of predators or competitors. Laboratory experiments showed that stacking is density dependent and probably the result of limitation of primary attachment space. Removals of significant predators (sea otters and Chumash Indians) of adult abalone during the past two centuries probably led to increased densities of black abalone, which in turn has had an indirect effect on the prevalence of stacking.     

Malignant Melanoma—Profile of an Epidemic

Cutaneous malignant melanoma is occurring in epidemic proportions in the United States. To provide a profile of persons at risk and the epidemiologic features of malignant melanoma, we reviewed the records of 325 patients with cutaneous malignant melanoma seen at the University of Colorado Health Sciences Center between 1973 and 1983. Most patients had fair skin, brown or blonde hair, blue or green eyes, and had difficulty in suntanning. The majority of melanomas (72%) developed in preexisting nevi. In women, melanomas were most common on the extremities, and in men they occurred most frequently on the trunk, head or neck. The most frequently noted depth of invasion was Clark''s level IV. At diagnosis, most of the patients (77%) were at stage I. We conclude that malignant melanoma constitutes a major disease problem in the western United States that is largely preventable with appropriate physician and patient education.     

Orientational oscillations of the peptide groups of an α-helix

The low-energy orientational oscillations of the peptide groups of an -helix are considered and the value of the frequency is estimated to be in agreement with experiments. Approximate formulae are derived for the projection of a dipole moment on the helix axis and for the helix parameters. Within the framework of a three-chain model, the asymptotics of the soliton solution is obtained using a discrete approach.The analysis of -helix geometry exhibits two types of low-frequency oscillations of the -helix. The first one is connected with atom movements along the helix axis with the peptide groups twisting around the helix axis. Accordingly, it changes the hydrogen bond lengths between neighbouring peptide groups. In the second case, the slopes of the peptide groups to the helix axis oscillate without the helix parameters changing. Here, the energy of interactions between peptide-group dipoles is changed and, as a result, the oscillations have an optical nature. The frequency of the optical orientational oscillations is approximately 100 cm^-1.     

The effect of isozyme selection on metric characters in an interspecific backcross of tomato — basis of an early screening procedure

Summary The extent of correlation was estimated between isozyme genotypes and the four widely segregating characters — leaf segment W/L ratio, stigma exsertion, fruit weight, and seed weight — in the first backcross of F₁ Lycopersicon esculentum x Solanum pennellii to the former parent. The inbred parents differ in their alleles at the 12 tested isozymic loci, which are known to mark a minimum of eight of the twelve tomato chromosomes. Based on the isozyme data, a mean heterozygosity value, ¯H, was calculated which estimates the proportion of pennillii alleles in each individual. Correlations between mean heterozygosity and observed levels of each quantitative trait were highly significant and positive or negative as expected from the relative parental values. Plants with the lowest mean heterozygosity — i.e., closest to the esculentum zymotype also had mean values closest to those of this parent amongst the whole backcross population for each of the quantitative traits.Bivariate and multiple regression analysis was used to evaluate the ability of isozymes vs diagnostic morphological characters to estimate the portion of recurrent parent genes carried in each backcross individual. The results suggest that isozyme data gives better estimates than single diagnostic morphological characters and approach the level obtained by combinations of three morphological traits. Since electrophoretic determinations are made on small seedlings, selection at that stage can effect great savings of space and effort by greatly deminishing the size of the population needed at maturity. As such, isozyme selection would precede morphological selection but not replace it, thus the predictive value of these biochemical markers as well as diagnostic morphological characters could be obtained.     

Adaptation of an insect cell line of Spodoptera frugiperda to grow at 37°C: Characterization of an endodiploid clone

Summary Sf21 and Sf9 cell lines established from the lepidoptera Spodoptera frugiperda do not display major induction of heat shock proteins when exposed to a temperature of 37°C. After some months of adaptation at 37°C we obtained two new cell lines, Sf21-HT and SF9-HT, which have now been established for several years in our laboratory. The Sf9-HT line displays a slightly shorter doubling time at 37°C than the wild type at 28°C, but cell lethality gives rise to an earlier growth arrest. The composition of total lipid extract from heat-adapted cells reveals a higher sphingomyelin to phosphatidylcholine ratio and a higher percentage of saturated fatty acids, which are expected for the lower membrane fluidity, required for thermotolerance. The cell volume of Sf9-HT is doubled, and by flow cytometry we showed that the DNA content is twice that in the parental cell line. Karyotypic examination of metaphasic cells achieved under epifluorescence microscopy revealed a doubled chromosome number in Sf9-HT.