Sensory cues of predation risk generate sex-specific changes in neural activity and behavior, but not hormones, in Trinidadian guppies.

How an organism responds to risk depends on how that individual perceives such risk. Integrating cues from multiple sensory modalities allows individuals to extract information from their environment, and whether and how the brain and body respond differently to different sensory cues can help reveal mechanistic decision-making processes. Here, we assessed neural, hormonal, and behavioral responses to different sensory cues of predation risk in Trinidadian guppies (Poecilia reticulata). Adult guppies were assigned to one of four treatment groups: control, visual, olfactory, and both sensory cues combined from a natural predator, the pike cichlid (Crenicichla alta), for 2 h. We found no difference in glucocorticoid response to any cue. However, we found behavioral and neural activation responses to olfactory-only cues. In addition, we found a sex by treatment effect, where males showed greater changes in neural activation in brain regions associated with avoidance behavior, while females showed greater changes in neural activation in regions associated with social behavior and memory, mirroring sex by treatment differences in behavioral antipredator responses. Altogether, our results demonstrate that single and combinatory cues may influence risk-taking behavior differently based on sex, suggesting that perception and integration of cues can cascade into sex differences in behavior.

The fate of cells undergoing spontaneous DNA damage during development.

Embryonic development involves extensive and often rapid cell proliferation. An unavoidable side effect of cell proliferation is DNA damage. The consequences of spontaneous DNA damage during development are not clear. Here, we define an approach to determine the effects of DNA damage on cell fate choice. Using single cell transcriptomics, we identified a subpopulation of Dictyostelium cells experiencing spontaneous DNA damage. Damaged cells displayed high expression of rad51, with the gene induced by multiple types of genotoxic stress. Using live imaging, we tracked high Rad51 cells from differentiation onset until cell fate assignment. High Rad51 cells were shed from multicellular structures, excluding damaged cells from the spore population. Cell shedding resulted from impaired cell motility and defective cell-cell adhesion, with damaged cells additionally defective in activation of spore gene expression. These data indicate DNA damage is not insulated from other aspects of cell physiology during development and multiple features of damaged cells prevent propagation of genetic error. Our approach is generally applicable for monitoring rare subpopulations during development, and permits analysis of developmental perturbations occurring within a physiological dynamic range.

Co-optimization of Heavy-Duty Fuels and Engines: Cost Benefit Analysis and Implications.

Heavy-duty vehicles require expensive aftertreatment systems for control of emissions such as particulate matter (PM) and nitrogen oxides (NOx) to comply with stringent emission standards. Reduced engine-out emissions could potentially alleviate the emission control burden, and thus bring about reductions in the cost associated with aftertreatment systems, which translates into savings in vehicle ownership. This study evaluates potential reductions in manufacturing and operating costs of redesigned emission aftertreatment systems of line-haul heavy-duty diesel vehicles (HDDVs) with reduced engine-out emissions brought about by co-optimized fuel and engine technologies. Three emissions reduction cases representing conservative, medium, and optimistic engine-out emission reduction benefits are analyzed, compared to a reference case: the total costs of aftertreatment systems (TCA) of the three cases are reduced to $11,400(1.63 ¢/km), $9,100 (1.30 ¢/km), and $8,800 (1.26 ¢/km), respectively, compared to $12,000 (1.71 ¢/km) for the reference case. The largest potential reductions result from reduced diesel exhaust fluid (DEF) usage due to lower NOx emissions. Downsizing aftertreatment devices is not likely, because the sizes of devices are dependent on not only engine-out emissions, but also other factors such as engine displacement. Sensitivity analysis indicates that the price and usage of DEF have the largest impacts on TCA reduction.

Safety and efficacy of parenteral iron in children with inflammatory bowel disease.

AIMS: Iron deficiency anaemia frequently complicates inflammatory bowel disease (IBD) in children and adults. Oral iron may exacerbate gastrointestinal symptoms and absorption may be insufficient in intestinal inflammation. Even where oral iron is successful, repletion of iron stores can be unacceptably slow. Intravenous iron compounds were in the past associated with serious adverse reactions and historically were considered a last resort in children. New generation preparations have a safer profile in adults, although reluctance to use them in children may persist, where safety data are lacking. We investigate the safety and efficacy of ferric carboxymaltose and iron sucrose in children. METHODS: We retrospectively identified all children with IBD who received parenteral iron over a 38-month period in a single regional referral centre. Safety, tolerability and adverse events were established by case note review. Efficacy was assessed by change in haematinic indices pre- and post-treatment. RESULTS: Forty-one children (18 male; median age 14 years, range 3-17) received a total of 104 iron infusions. Of these, 44% (18) had Crohn's disease; 56% (23) ulcerative colitis. Thirty-five received ferric carboxymaltose, seven iron sucrose and one both. Three children developed mild rash post infusion which resolved quickly with chlorphenamine. Mean increase in haemoglobin was 2.5 g dl-1 (0.3-5.8). Iron levels increased by a mean of 8.4 g dl-1 (1-25), transferrin saturation by 16.2% (2-47). Transferrin decreased by 0.84 g dl-1 (0.3-3.4). CONCLUSIONS: New generation parenteral iron preparations are safe, well tolerated and efficacious in children with iron deficiency anaemia and IBD.

Real-life Anti-tumor Necrosis Factor Experience in More Than 500 Patients: High Co-immunosuppression Rates But Low Rates of Quantifying Treatment Response.

OBJECTIVE: The aim of this study was to measure the effectiveness, safety, and use of anti-tumor necrosis Factor (TNF) therapy in pediatric inflammatory bowel disease in the United Kingdom (UK). METHODS: Prospective UK audit of patients newly starting anti-TNF therapy. Disease severity was assessed using Physician Global Assessment +/or the Paediatric Crohn Disease Activity Index. RESULTS: A total of 37 centers participated (23/25 specialist pediatric inflammatory bowel disease sites). A total of 524 patients were included: 429 with Crohn disease (CD), 76 with ulcerative colitis (UC), and 19 with IBD unclassified (IBDU). Eighty-seven percent (488/562) of anti-TNF was infliximab; commonest indication was active luminal CD 77% (330/429) or chronic refractory UC/IBDU 56% (53/95); 79% (445/562) had concomitant co-immunosuppression. In CD (267/429 male), median time from diagnosis to treatment was 1.42 years (interquartile range 0.63-2.97). Disease (at initiation) was moderate or severe in 91% (156/171) by Physician Global Assessment compared to 41% (88/217) by Paediatric Crohn Disease Activity Index (Kappa (κ) 0.28 = only "fair agreement"; P < 0.001.Where documented, 77% (53/69) of patients with CD responded to induction; and 65% (46/71) entered remission. A total of 2287 infusions and 301.96 years of patient' follow-up (n = 385) are represented; adverse events affected 3% (49/1587) infliximab and 2% (2/98) adalimumab infusions (no deaths or malignancies). Peri-anal abscess drainage was less common after anti-TNF initiation (CD), that is 26% (27/102) before, 7% (3/42) after (P = 0.01); however, pre and post anti-TNF data collection was not over equal time periods. CONCLUSIONS: Anti-TNFs are effective treatments, usually given with thiopurine co-immunosuppression. This study highlights deficiencies in formal documentation of effect and disparity between disease severity scoring tools, which need to be addressed to improve ongoing patient care.

Enhancing self-care, adjustment and engagement through mobile phones in youth with HIV.

AIM: To evaluate the effectiveness of mobile phones in enhancing self-care, adjustment and engagement in non-disclosed youth living with HIV. BACKGROUND: Youth aged 15-24 years represent 42% of new HIV infections globally. Youth who are aware of their HIV status generally do not disclose it or utilize HIV-related facilities because of fear of stigma. They rely on the Internet for health maintenance information and access formal care only when immune-compromised and in crisis. INTRODUCTION: This study shows how non-disclosed youth living with HIV can be reached and engaged for self-management and adjustment through mobile phone. STUDY DESIGN: One-group pre-test/post-test experimental design was used. METHODS: Mobile phones were used to give information, motivation and counselling to 19 purposively recruited non-disclosed youth with HIV in Calabar, South-South Nigeria. Psychological adjustment scale, modified self-care capacity scale and patient activation measure were used to collect data. Data were analysed using PASW 18.0. RESULTS: Scores on self-care capacity, psychological adjustment and engagement increased significantly at post-test. HIV-related visits to health facilities did not improve significantly even at 6 months. Participants still preferred to consult healthcare providers for counselling through mobile phone. DISCUSSION: Mobile phone-based interventions are low cost, convenient, ensure privacy and are suitable for youth. Such remote health counselling enhances self-management and positive living. CONCLUSION AND IMPLICATIONS FOR HEALTH POLICY: Mobile phones enhance self-care, psychological adjustment and engagement in non-disclosed youth living with HIV, and can be used to increase care coverage. Findings underline the importance of policies to increase access by locating, counselling and engaging HIV-infected youth in care.

Evolution of in vitro cow's milk protein-specific inflammatory and regulatory cytokine responses in preterm infants with necrotising enterocolitis.

BACKGROUND: We have previously reported evidence of in vitro sensitisation to cow's milk protein in peripheral blood mononuclear cells (PBMCs) in preterm infants with necrotising enterocolitis (NEC). In the present study, we document the changes in the PBMC responses to stimulation with mitogen (phytohaemagglutinin) and cow's milk proteins ß-lactoglobulin (ß-lg) and casein over time: from the acute presentation of NEC, to initial recovery (reinitiation of enteral feeds), to full recovery (full feeding). METHODS: Of the 14 preterm infants recruited with acute NEC, 12 were followed until fully enterally fed (2 died during the acute phase). Cytokine secretion (interferon-γ [IFN-γ], interleukin 4, [IL-4], IL-10, and transforming growth factor-ß1 [TGF-ß1]) by PBMCs in response to stimulation by phytohaemagglutinin, ß-lg, and casein was measured by enzyme-linked immunospot in the acute phase and subsequently at recovery and full recovery. RESULTS: The high levels of cytokine secretion (IFN-γ, IL-4, IL-10, and TGF-ß1) observed in response to ß-lg and casein in the acute phase increased by a further 50% to 100% at recovery (P < 0.005). At full recovery (full feeding), however, IFN-γ, IL-4, and IL-10 secretion response had returned to, or below, acute-phase levels, whereas the augmented TGF-ß1 response was maintained (P = 0.005 vs acute level). This response pattern was similar for casein, and did not appear to be influenced by the nature of the feed used following NEC (breast milk/formula/hydrolysed formula). CONCLUSIONS: The evolution of the cytokine response profile in parallel with the clinical recovery from NEC is consistent with a putative role for TGF-ß1 in regulation of inflammation, and possibly also oral tolerance.

In vitro cow's milk protein-specific inflammatory and regulatory cytokine responses in preterm infants with necrotizing enterocolitis and sepsis.

Enteral feeding with cow's milk formula is associated with neonatal necrotizing enterocolitis (NEC) and sepsis. Dietary antigen sensitization may play a role in promoting and/or sustaining inflammation in both conditions. Aiming at investigating cow's milk protein (CMP)-specific cytokine responses in preterm infants with NEC and sepsis, 14 babies with NEC, 14 matched healthy controls, and 10 septic controls were recruited. Unstimulated and stimulated peripheral blood mononuclear cells (PBMCs) secreting IFN-γ, IL-4, IL-10, and TGF-ß1 were counted by the single-cell enzyme-linked immunospot (ELISPOT) assay. During the acute phase of NEC, patients showed a general pattern of a high level of cytokine secretion both when unstimulated and stimulated by mitogen [phytohaemagglutinin (PHA)] and CMPs: beta-lactoglobulin (ß-lg) and casein. These responses were more marked to ß-lg for IFN-γ, IL-4, and IL-10 than TGF-ß1. Cytokine responses in sepsis were lower than in NEC (lowest in healthy controls, with a minimal TGF-ß1 response). At term, lower frequencies of cytokine-secreting cells were elicited than during the acute phase, except for TGF-ß1 secreting cells, which increased at term (in response to PHA and CMPs) particularly following not only NEC but also sepsis.

An analysis of field-aged diesel particulate filter performance: particle emissions before, during, and after regeneration.

A field-aged, passive diesel particulate filter (DPF) used in a school bus retrofit program was evaluated for emissions of particle mass and number concentration before, during, and after regeneration. For the particle mass measurements, filter samples were collected for gravimetric analysis with a partial flow sampling system, which sampled proportionally to the exhaust flow. A condensation particle counter and scanning mobility particle sizer measured total number concentration and number-size distributions, respectively. The results of the evaluation show that the number concentration emissions decreased as the DPF became loaded with soot. However, after soot removal by regeneration, the number concentration emissions were approximately 20 times greater, which suggests the importance of the soot layer in helping to trap particles. Contrary to the number concentration results, particle mass emissions decreased from 6 +/- 1 mg/hp-hr before regeneration to 3 +/- 2 mg/hp-hr after regeneration. This indicates that nanoparticles with diameters less than 50 nm may have been emitted after regeneration because these particles contribute little to the total mass. Overall, average particle emission reductions of 95% by mass and 10,000-fold by number concentration after 4 yr of use provided evidence of the durability of a field-aged DPF. In contrast to previous reports for new DPFs in which elevated number concentrations occurred during the first 200 sec of a transient cycle, the number concentration emissions were elevated during the second half of the heavy-duty Federal Test Procedure (FTP) when high speed was sustained. This information is relevant for the analysis of mechanisms by which particles are emitted from field-aged DPFs.

How to Investigate the Origins of Novelty: Insights Gained from Genetic, Behavioral, and Fitness Perspectives.

Biologists are drawn to the most extraordinary adaptations in the natural world, often referred to as evolutionary novelties, yet rarely do we understand the microevolutionary context underlying the origins of novel traits, behaviors, or ecological niches. Here we discuss insights gained into the origins of novelty from a research program spanning biological levels of organization from genotype to fitness in Caribbean pupfishes. We focus on a case study of the origins of novel trophic specialists on San Salvador Island, Bahamas and place this radiation in the context of other rapid radiations. We highlight questions that can be addressed about the origins of novelty at different biological levels, such as measuring the isolation of novel phenotypes on the fitness landscape, locating the spatial and temporal origins of adaptive variation contributing to novelty, detecting dysfunctional gene regulation due to adaptive divergence, and connecting behaviors with novel traits. Evolutionary novelties are rare, almost by definition, and we conclude that integrative case studies can provide insights into this rarity relative to the dynamics of adaptation to more common ecological niches and repeated parallel speciation, such as the relative isolation of novel phenotypes on fitness landscapes and the transient availability of ecological, genetic, and behavioral opportunities.

Como Investigar as Origens da Novidade: Ideias Obtidas a Partir de Perspectivas da Genética, do Comportamento e de Fitness (How to Investigate the Origins of Novelty: Insights Gained from Genetic, Behavioral, and Fitness Perspectives) Biólogos são atraídos pelas adaptações mais extraordinárias do mundo natural, muitas vezes chamdas de novidades evolutivas, mas raramente entendemos o contexto microevolutivo subjacente às origens de novas características, novos comportamentos ou nichos ecológicos. Aqui discutimos ideias obtidas sobre as origens da novidade evolutiva a partir de um programa de pesquisa abrangendo níveis biológicos de organização de genótipo para fitness em pupas do Caribe. Nós nos concentramos em um estudo de caso sobre as origens de novos especialistas tróficos na ilha de São Salvador, Bahamas, e colocamos essa radiação no contexto de outras radiações rápidas. Destacamos questões que podem ser abordadas sobre as origens da novidade evolutiva em diferentes níveis biológicos, como medir o isolamento de novos fenótipos no cenário adaptativo, localizando as origens espaciais e temporais da variação adaptativa que contribuem para a novidade evolutiva, detectando a regulação gênica disfuncional devido à divergência adaptativa, e conectando comportamentos com novas características. As novidades evolutivas são raras, quase por definição, e concluímos que estudos de caso integrativos podem fornecer ideias sobre essa raridade em relação à dinâmica de adaptação a nichos ecológicos mais comuns e especiação paralela repetitiva, como o relativo isolamento de novos fenótipos em cenários adaptativos e a disponibilidade transitória de oportunidades ecológicas, genéticas, e comportamentais. Translated to Portuguese by G. Sobral (gabisobral@gmail.com).

The Atypical MAP Kinase ErkB Transmits Distinct Chemotactic Signals through a Core Signaling Module.

Signaling from chemoattractant receptors activates the cytoskeleton of crawling cells for chemotaxis. We show using phosphoproteomics that different chemoattractants cause phosphorylation of the same core set of around 80 proteins in Dictyostelium cells. Strikingly, the majority of these are phosphorylated at an [S/T]PR motif by the atypical MAP kinase ErkB. Unlike most chemotactic responses, ErkB phosphorylations are persistent and do not adapt to sustained stimulation with chemoattractant. ErkB integrates dynamic autophosphorylation with chemotactic signaling through G-protein-coupled receptors. Downstream, our phosphoproteomics data define a broad panel of regulators of chemotaxis. Surprisingly, targets are almost exclusively other signaling proteins, rather than cytoskeletal components, revealing ErkB as a regulator of regulators rather than acting directly on the motility machinery. ErkB null cells migrate slowly and orientate poorly over broad dynamic ranges of chemoattractant. Our data indicate a central role for ErkB and its substrates in directing chemotaxis.

Mutations in the histone methyltransferase gene KMT2B cause complex early-onset dystonia.

Histone lysine methylation, mediated by mixed-lineage leukemia (MLL) proteins, is now known to be critical in the regulation of gene expression, genomic stability, cell cycle and nuclear architecture. Despite MLL proteins being postulated as essential for normal development, little is known about the specific functions of the different MLL lysine methyltransferases. Here we report heterozygous variants in the gene KMT2B (also known as MLL4) in 27 unrelated individuals with a complex progressive childhood-onset dystonia, often associated with a typical facial appearance and characteristic brain magnetic resonance imaging findings. Over time, the majority of affected individuals developed prominent cervical, cranial and laryngeal dystonia. Marked clinical benefit, including the restoration of independent ambulation in some cases, was observed following deep brain stimulation (DBS). These findings highlight a clinically recognizable and potentially treatable form of genetic dystonia, demonstrating the crucial role of KMT2B in the physiological control of voluntary movement.

Age-related alterations in blood and colonic dendritic cell properties.

BACKGROUND: Dendritic cells (DC) determine initiation, type and location of immune responses and, in adults, show decreased Toll-like receptors and some increased cytokine levels on ageing. Few studies in children have characterised DC or explored DC-related mechanisms producing age-related immune changes. RESULTS: The pDC marker BDCA2 (but not CD123) was absent in pre-pubertal children and numbers of pDC decreased with age. Blood and colonic DC were more mature and activated in adults. Decrease in pDC numbers correlated with reduced GM-CSF levels with aging, but increasing IL-4 and IL-8 levels correlated with a more activated DC profile in blood. CXCL16 levels decreased with age. METHODS: Blood and colonic DC phenotypes were determined in healthy adults and children by flow cytometry and correlated with aging. Blood DC were divided into plasmacytoid (pDC) and myeloid (mDC) while only mDC were identified in colon. Serum cytokine levels were determined by multiplex cytokine assays and correlated with DC properties. CONCLUSIONS: In children, lack of BDCA2, a receptor mediating antigen capture and inhibiting interferon induction, may be immunologically beneficial during immune development. Conversely, reduced pDC numbers, probably secondary to decreasing GM-CSF and increasing cytokine-induced maturation of DC are likely to determine deteriorating immunity with ageing.

Pollutant emissions and environmental assessment of ethyl 3-ethoxybutyrate, a potential renewable fuel.

Renewable and bio-based transportation fuel sources can lower the life-cycle greenhouse gas emissions from vehicles. We present an initial assessment of ethyl 3-ethoxybutyrate (EEB) as a biofuel in terms of its performance as a fuel oxygenate and its persistence in the environment. EEB can be produced from ethanol and poly-3-hydroxybutyrate, a bacterial storage polymer that can be produced from non-food biomass and other organic feedstocks. Physicochemical properties of EEB and fuel-relevant properties of EEB-gasoline blends were measured, emissions of criteria pollutants from EEB as a gasoline additive in a production vehicle were evaluated, and fate and persistence of EEB in the environment were estimated. EEB solubility in water was 25.8 g/L, its Kow was 1.8, and its Henry's Law constant was 1.04 × 10(-5) atm-m(3)/mole. The anti-knock index values for 5 and 20 % v/v EEB-gasoline blends were 91.6 and 91.9, respectively. Reductions in fuel economy were consistent with the level of oxygenation, and criteria emissions were met by the vehicle operated over the urban dynamometer driving cycle (FTP 75). Predicted environmental persistence ranged from 15 to 30 days which indicates that EEB is not likely to be a persistent organic pollutant. In combination, these results suggest a high potential for the use of EEB as a renewable fuel source.

Functional and conformational properties of mouse hemoglobins.

Hemoglobins from four strains of mice (C3H/SW, DBA/2J, C57BL6/Kh and A.TH) examined showed pH-dependent heme-heme interactions. The oxygen affinity and cooperativity are reduced at acidic pH. The oxygen equilibrium parameters increase as a function of increasing pH and at physiological pH values they are similar to the corresponding values of human hemoglobin A. The nitrosyl derivatives of these mouse hemoglobins undergo a quaternary structural transition to the T state in going from pH 7.0 to 6.0. These functional and conformational properties are indicative of destabilised oxy structures of mouse hemoglobins at acidic pH. This study also confirms that the cysteine residue at beta 13(A10) position has no influence on the oxygen equilibrium properties or conformation of the molecule.

Differential effects of pH and inositol hexaphosphate on the spectroscopic properties of the alpha and beta subunits in methemoglobins M Milwaukee and A.

The effect of pH and inositol hexaphosphate on the electron spin resonance spectra of the alpha-hemes (g = 6.0) and the beta-hemes (g = 6.7) has been measured in methemoglobin M Milwaukee and compared with that of methemoglobin A (g = 6.0). The beta-hemes are found to be comparatively insensitive to both effectors while the alpha-hemes behave in a manner similar to the heme groups of methemoglobin A. Binding of inositol hexaphosphate enhances the high spin ESR signal of the alpha-hemes in both methemoglobins. Comparison of the optical properties of methemoglobins A and M Milwaukee over the pH range from 5.0 to 8.1 shows that inositol hexaphosphate has a differential effect on the subunit types in these two methemoglobins. At low pH the spectral changes observed upon inositol hexaphosphate binding arise primarily from the beta-hemes, while at neutral and alkaline pH these changes arise from both subunit types. The beta-heme spectral changes appear to be pH independent while those arising from the alpha-hemes are strongly pH dependent. It is concluded that it is the hydroxymet form of the alpha-hemes which undergoes spectral change upon inositol hexaphosphate binding to the beta-subunits. In methemoglobin A the spin state and paramagnetic susceptibility increase only in the neutral and alkaline pH ranges upon inositol hexaphosphate binding (Gupta, R.K. and Mildvan, R.S. (1975) J. Biol. Chem. 250, 246; Perutz, M.F., Sanders, J.K.M., Chenery, D.H., Noble, R.W., Penelly, R.R., Fung, L.W.-M., Ho, C., Giannini, I., Porschke, D. and Winkler, H. (1978) Biochemistry 17, 3640). Therefore the hydroxymet form of the alpha-hemes which is responsible for the observed spectral changes must also be responsible for these increases in the magnetic properties of methemoglobin A. Inositol hexaphosphate can bind to methemoglobin at alkaline pH if the beta-hemes are in the high spin form.

Control of systemic and local inflammation with transforming growth factor beta containing formulas.

Enteral nutrition therapy with liquid diet has been shown to be effective in achieving clinical remission in intestinal Crohn's disease. The mechanism of action of this therapy, however, is still poorly understood. As part of our assessment of the action of 3 related polymeric enteral therapies, we have used a variety of techniques to document the histological and cytokine responses, in the mucosa and, systemically, to these treatments. The feeds studied (AL110, Modulen IBD and ACD004 [Nestle, Vevey, Switzerland]) all have casein as the protein source, are lactose free and are rich in transforming growth factor beta (TGF-beta). They have all been shown to induce clinical remission associated with mucosal healing. In the case of Modulen IBD, as well as mucosal macroscopic and histological healing there was a fall in mucosal proinflammatory cytokines: interleukin-1 mRNA in colonic and ileal, interleukin-8 mRNA in the colon and interferon gamma mRNA in the ileum, but a rise in the regulatory cytokine TGF-beta mRNA in the ileum. These results indicate that these formulas are influencing the disease process itself, and thus suggest that the clinical remission achieved is a result of a reduction in inflammation, rather than a consequence of some other nutrition effect.

Sequence analysis of arcelin 2, a lectin-like plant protein.

The nucleotide sequence of the cDNA clone encoding arcelin 2 (Arc2), one member of a family of closely related lectin-like plant toxins from wild bean accession, is presented. The sequence contains a 265-amino acid (aa) open reading frame and is 99.3% homologous to Arc1, another of the four electrophoretic variants with proven antibiosis characters. These two proteins differ by four aa residues. Based on cross hybridizations of RNAs, it is assumed that Arc4 is more divergent than Arc1 and Arc2. Furthermore, it is likely that at least three of the variants are polypeptides of similar size and the observed molecular weight differences between them are due to differences in the number of glycosylation sites.

Regulation of cholesterol side-chain cleavage cytochrome P-450 gene expression in adrenal cells in monolayer culture.

Utilizing a cDNA probe specific for bovine cytochrome P-450scc and primary monolayer cultures of bovine adrenocortical cells and human fetal adrenal cells, it has been shown that the chronic action of ACTH on the adrenal cortex includes regulation of P-450scc gene expression at the transcriptional level. The bovine P-450scc cDNA hybridizes strongly to human, pig and rat RNA. Advantage was taken of the cross-reactivity of the bovine P-450scc cDNA with human P-450scc RNA to examine the regulation of P-450scc gene expression by ACTH in human fetal adrenal cells. This process is mediated by cyclic AMP and is inhibited by cycloheximide, in a fashion similar to bovine adrenocortical cells, suggestive that a protein factor(s) activates the response in both species. Hence, the actions of ACTH to regulate P-450scc gene expression in bovine adult adrenocortical cells and human fetal adrenal cells appear to proceed by similar mechanisms.