Characteristics and Management of Ocular Involvement in Individuals with Mpox Disease

Ocular complications of mpox infection have a prevalence of 1% in the current outbreak. Although conjunctivitis is the most common presentation, corneal involvement may occur. Tecovirimat is recommended for severe ocular mpox involvement.

Bilateral facial palsy with paresthesias, variant of Guillain-Barré syndrome following COVID-19 vaccine: A case series of 9 patients

Several cases of Guillain-Barré Syndrome (GBS) associated with COVID-19 vaccination have been reported, including the rare subtype known as Bilateral Facial Palsy with paresthesias (BFP). To date, it is not known whether a causal relationship may exist between the two. We report 9 cases of BFP in patients vaccinated against COVID-19 in the previous month. Nerve conduction studies revealed demyelinating polyneuropathy in 4 patients, and 5 presented bilateral, focal facial nerve involvement, exclusively. Ganglioside antibody panel was positive in 4 patients (anti-GM1=2, anti-GD1a=1 and anti-sulfatide=1). Seven patients received intravenous immunoglobulin treatment, one plasma exchange, and one patient died from sudden cardiac arrest following arrhythmia before treatment could be administered. Rates of BFP following COVID-19 vaccination, did not differ from those reported in previous series. Epidemiological studies are essential to determine whether a causal relationship may exist between this rare form of GBS and COVID-19 vaccination.

Impaired Suppression of Glucagon in Obese Subjects Parallels Decline in Insulin Sensitivity and Beta-Cell Function

AIM

To examine the relationship between plasma glucagon levels and insulin sensitivity and insulin secretion in obese subjects.

METHODS

Suppression of plasma glucagon was examined in 275 obese Hispanic Americans with varying glucose tolerance. All subjects received a 2-hour oral glucose tolerance test (OGTT) and a subset (n = 90) had euglycemic hyperinsulinemic clamp. During OGTT, we quantitated suppression of plasma glucagon concentration, Matsuda index of insulin sensitivity, and insulin secretion/insulin resistance (disposition) index. Plasma glucagon suppression was compared between quartiles of insulin sensitivity and beta-cell function.

RESULTS

Fasting plasma glucagon levels were similar in obese subjects with normal glucose tolerance (NGT), prediabetes, and type 2 diabetes (T2D), but the fasting glucagon/insulin ratio decreased progressively from NGT to prediabetes to T2D (9.28 ± 0.66 vs 6.84 ± 0.44 vs 5.84 ± 0.43; P < 0.001). Fasting and 2-hour plasma glucagon levels during OGTT progressively increased and correlated positively with severity of insulin resistance (both Matsuda index and euglycemic hyperinsulinemic clamp). The fasting glucagon/insulin ratio declined with worsening insulin sensitivity and beta-cell function, and correlated with whole-body insulin sensitivity (Matsuda index, r = 0.81; P < 0.001) and beta-cell function (r = 0.35; P < 0.001). The glucagon/insulin ratio also correlated and with beta-cell function during OGTT at 60 and 120 minutes (r = -0.47; P < 0.001 and r = -0.32; P < 0.001).

CONCLUSION

Insulin-mediated suppression of glucagon secretion in obese subjects is impaired with increasing severity of glucose intolerance and parallels the severity of insulin resistance and beta-cell dysfunction.

Genotype-Phenotype Features of Germline Variants of the TMEM127 Pheochromocytoma Susceptibility Gene: A 10-Year Update

PURPOSE

This work aimed to evaluate genotype-phenotype associations in individuals carrying germline variants of transmembrane protein 127 gene (TMEM127), a poorly known gene that confers susceptibility to pheochromocytoma (PHEO) and paraganglioma (PGL).

DESIGN

Data were collected from a registry of probands with TMEM127 variants, published reports, and public databases.

MAIN OUTCOME ANALYSIS

Clinical, genetic, and functional associations were determined.

RESULTS

The cohort comprised 110 index patients (111 variants) with a mean age of 45 years (range, 21-84 years). Females were predominant (76 vs 34, P < .001). Most patients had PHEO (n = 94; 85.5%), although PGL (n = 10; 9%) and renal cell carcinoma (RCC, n = 6; 5.4%) were also detected, either alone or in combination with PHEO. One-third of the cases had multiple tumors, and known family history was reported in 15.4%. Metastatic PHEO/PGL was rare (2.8%). Epinephrine alone, or combined with norepinephrine, accounted for 82% of the catecholamine profiles of PHEO/PGLs. Most variants (n = 63) occurred only once and 13 were recurrent (2-12 times). Although nontruncating variants were less frequent than truncating changes overall, they were predominant in non-PHEO clinical presentations (36% PHEO-only vs 69% other, P < .001) and clustered disproportionately within transmembrane regions (P < .01), underscoring the relevance of these domains for TMEM127 function. Integration of clinical and previous experimental data supported classification of variants into 4 groups based on mutation type, localization, and predicted disruption.

CONCLUSIONS

Patients with TMEM127 variants often resemble sporadic nonmetastatic PHEOs. PGL and RCC may also co-occur, although their causal link requires further evaluation. We propose a new classification to predict variant pathogenicity and assist with carrier surveillance.

Detection of hotspots and rapid determination of methane emissions from landfills via a ground-surface method

We present a method for the rapid determination of methane emissions from landfills based on atmospheric dispersion theory, which suggests that the methane concentration, at a small distance from the soil/atmosphere interface, is proportional to its flux. Thus, after suitable calibration, the determination of methane concentrations close to the ground allows for flux determination in a shorter time than with standard enclosure techniques. This concept was tested using a surface probe in direct contact with the ground. The probe extracts a continuous sample of the air at the probe/ground interface and transports it to a portable methane analyzer. It was observed that stable methane concentrations were measured 30 s after the probe was positioned at the measurement point. These concentrations correlated well with the fluxes measured by standard static chambers. The method was used to determine the fluxes at 217 points within a 90,000 m(2) landfill. These measurements facilitated mapping of the CH4 emissions and the localization of hotspots. We conclude that the method is simple, effective, and relatively quick, compared to existing standard methods.

Fully atomistic molecular dynamics simulations of the behavior of a simple model of crude oil confined between graphene planes

We present and discuss the results of molecular dynamics computer simulations of crude oil confined between graphene planes. The crude oil is represented as a mixture of alkanes having 6 </= n </= 30 carbons that contain explicit hydrogen atoms; the confining structure is a floor and ceiling, each comprised of graphene sheets. At low temperature, the system adsorbs completely onto the confining layers, showing an interesting domain structure in its own right. As the temperature increases, various species desorb in order of increasing molecular mass and enter the vapor phase between the confining sheets. Desorption proceeds through a roughening of the adsorbed layers but does not appear to couple to any inter- or intramolecular phase transition on the surfaces for any given species. Allowing the graphene sheets to be flexible affects the rate of adsorption as well as the in-plane order and molecular confirmations of the adsorbate. Cursory simulations with more than one layer show droplet-like adsorption at low temperatures and complicated dynamics, which shift the initial desorption temperatures to lower values than those for the monolayer and cause the desorption temperature and process to be much less defined. The results presented here are suggestive of a method of separating alkane mixtures at temperatures significantly different from those of conventional refining processes.

Morphology-diet relationships in four killifishes (Teleostei, Cyprinodontidae, Orestias) from Lake Titicaca

This study explores the relationship between morphology and diet in four Andean killifishes (Orestias) from Lake Titicaca that are known to differ in habitat use. Species that fed preferentially on amphipods (Orestias albus) or molluscs (Orestias luteus) separated in multivariate space from other species that feed on cladocera and algae (Orestias agassii and Orestias jussiei). Generally, specimens feeding on cladocera were characterized by a short, blunt nose with a small mouth; whereas, specimens feeding on amphipods exhibited a long snout with a large mouth. Specimens including molluscs in their diet tended to have a larger posterior part of the head and the larger opercles than others; while the occurrence of substratum in gut content was generally related to a short but deep head. The present analysis suggests that the littoral O. jussiei has an intermediate phenotype and diet between the pelagic (O. agassii) and benthic (O. albus and O. luteus) species. Results suggest that resource partitioning was occurring and that several morphological traits relate to characteristics of the diet, and it is inferred that the benthic, the pelagic and the littoral zones in the lake host different prey communities constituting distinct adaptive landscapes.

Spanish validation of the HIV dementia scale in women

HIV infection is increasing in minority groups, particularly in African American and Hispanic women. Although the incidence of HIV dementia has decreased since the advent of highly active antiretroviral treatment, prevalence of neurocognitive complications has increased as patients are now living longer. This study's purpose was to determine the psychometric properties of the Spanish-language HIV Dementia Scale (HDS) in a group of HIV-infected women. We recruited 96 women: 60 HIV-seropositive and 36 HIV-seronegative. Modification of the HDS into a Spanish-language version consisted of translating the instructions, substituting four words in Spanish (gato, media, azul, piña), increasing 1 second in the psychomotor speed because the Spanish alphabet has more letters than the English alphabet, and not offering clues for memory recall. Cognitive impairment (CI) was defined according to the modified American Academy of Neurology HIV-dementia criteria including an asymptomatic CI group. Statistical analysis consisted of analysis of variance to determine group differences and receiver operator characteristics (ROC) to determine the optimal cutoff point for the screening of CI. HDS-Spanish total score and subscores for psychomotor speed and memory recall showed significant differences between HIV-seronegative and women with HIV-dementia (p < 0.001) and between HIV-seropositive women with normal cognition and those with HIV-dementia (p < 0.001). The optimal cutoff point of 13 or less had performance characteristics of 87% sensitivity and 46% specificity for HIV-associated CI (50.0% positive predictive value, 85.0% negative predictive value). The HDS-Spanish translation offers a useful screening tool with value for the identification of Hispanic women at risk of developing HIV-associated symptomatic neurocognitive disturbances.

Differential distribution of antibodies to different viruses in young animals in the free-ranging rhesus macaques of Cayo Santiago

BACKGROUND

The breeding colony of free-ranging rhesus macaques was established in 1938 in Cayo Santiago (CS) with animals collected in northern India. The seroprevalence to cercopithecine herpesvirus type 1 (B virus) and simian retroviruses has been studied previously.

RESULTS

This is the first report on the seropositivity to different viruses using samples collected shortly after removing animals (n = 245) from CS. All samples were negative for measles, simian immunodeficiency virus and simian type D retroviruses. The overall prevalence of antibodies was around 50% for simian T-lymphotropic virus I (STLV-I). For B virus, the prevalence was 38%.

CONCLUSIONS

Data obtained showed marked differences in the antibody distribution to B virus and STLV-I within the free-ranging colony of rhesus macaques. Implication of these data for the Specific Pathogen Free program at the Caribbean Primate Research Center are also discussed.

Stress-induced germ cell apoptosis by a p53 independent pathway in Caenorhabditis elegans

In Caenorhabditis elegans, several distinct apoptosis pathways have been characterized in the germline. The physiological pathway is though to eliminate excess germ cells during oogenesis to maintain gonad homeostasis and it is activated by unknown mechanisms. The DNA damage-induced germ cell apoptosis occurs in response to genotoxic agents and involves the proteins EGL-1 and CED-13, and the DNA damage response protein p53. Germ cell apoptosis can also be induced in response to pathogen infection through an EGL-1 dependent pathway. To gain insight into the mechanism and functions of germ cell apoptosis, we investigated whether and how other forms of stress induce this cell death. We found that oxidative, osmotic, heat shock and starvation stresses induce germ cell apoptosis through a p53 and EGL-1 independent pathway. We also learned that the MAPK kinases MEK-1 and SEK-1, and the p53 antagonist protein ABL-1, are essential for stress-induced germ cell apoptosis. We conclude that in C. elegans responses to various stresses that do not involve genotoxicity include an increase in germ cell apoptosis through the physiological pathway.

Anxiogenic-like activity of 3,4-methylenedioxy-methamphetamine ("Ecstasy") in the social interaction test is accompanied by an increase of c-fos expression in mice amygdala

3,4-Methylenedioxymethamphetamine (MDMA) is a synthetic amphetamine popularly known as "Ecstasy." Animal studies examining acute effects of MDMA on anxiety are unclear because although an anxiolytic-like action of MDMA in different animal models of anxiety has been described, there is also substantial evidence supporting an anxiogenic-like effect of this drug. To date, several studies have examined c-fos expression following MDMA administration in rats. However, there is no information about the MDMA-induced c-fos expression in mice previously tested in an animal model of anxiety. In this study, male mice were injected with MDMA (1, 8 and 15 mg/kg ip) and assessed for changes on anxiety and for the expression of the immediate early gene c-fos in the amygdala (central, basolateral and basomedial). Anxiety was evaluated by the "social interaction test." Ten behavioral categories were recorded: body care, digging, nonsocial exploration, exploration from a distance, social investigation, threat, attack, avoidance/flee, defense/submission and immobility. As compared with the control group, mice treated with MDMA (all doses) showed a decrease in mean duration and total time spent in social investigation behaviors, whereas avoidance/flee behaviors were significantly increased after treatment with this compound (8 and 15 mg/kg). Likewise, a significant increase in c-fos expression was found in the basolateral (all doses) and central (15 mg/kg) amygdala after MDMA administration. Overall, these findings indicate that MDMA exhibits an anxiogenic-like profile in the social interaction test in mice, and that central and basolateral amygdala might be involved in these anxiogenic-like effects of the drug.

Acute and subchronic effects of MDMA ("ecstasy") on anxiety in male mice tested in the elevated plus-maze

3,4-Methylenedioxymethamphetamine (MDMA) is a compound structurally similar to methamphetamine, which has become one of the most widely used illicit substances. Animal studies investigating acute effects of MDMA on anxiety are unclear since, although an anxiogenic-like action of MDMA in different animal models of anxiety has been mainly described, there is also evidence supporting an anxiolytic-like effect for this drug. An attempt was made to clarify the possible anxiogenic-like profile of MDMA (1, 8 and 15 mg/kg i.p.) by analyzing its effect on behavior of male mice in the elevated plus-maze test. Moreover, the possible development of tolerance to the effects of MDMA on anxiety after its subchronic administration for 5 consecutive days was examined. The parameters evaluated included: (1) total time in open arms, (2) total time in closed arms, (3) total time in central area, (4) number of open arm entries, (5) number of closed arm entries and (6) number of central area entries. Acute treatment with MDMA (8 mg/kg) significantly reduced the time spent in the open arms, as well as markedly increasing the number of entries in the closed arms and in the central area, as compared with the control group, suggesting that MDMA, at this dose, has an anxiogenic-like activity. Mice subchronically treated with the drug (1 and 8 mg/kg) displayed a notable reduction in the time spent in the open arms, accompanied by an increase in the time spent in the closed arms and in the central platform. These results indicate that the anxiogenic-like effect found after acute treatment is not only maintained but also more marked after subchronic treatment. In contrast, mice treated subchronically with the highest dose of MDMA (15 mg/kg) exhibited a significant increase in the time spent in the open arms as well as a marked reduction in the time spent in the closed arms, supporting an anxiolytic-like activity of the drug. A possible dual pharmacological property of MDMA on anxiety is suggested.

Attitudes toward animal research among psychology students in Spain

Animal research plays a central role in psychology, and its use, prevalence and quality depends on the attitudes of students who enter psychology in Spain. Attitudes among psychology students about the use of laboratory animals are not known, so the aim of this work was to analyze the attitudes of Spanish psychology students toward animal research. An attitude questionnaire of 15 items was given to 661 undergraduate students of the School of Psychology at the University of Málaga, Spain. Several results were found: (a) 65.7% of the respondents strongly agreed or agreed with animal research. General support for animal research was significantly higher by men than by women. (b) Support for animal research was higher for senior students, suggesting that the psychology curriculum or self-selection to remain in the program might influence students' attitudes. (c) Attitudes toward animal research were similar among students independent of the type of animal being used for research in biological or psychological studies. (d) 58% considered that laboratory animals never or almost never are inappropriately handled. (c) 55.6% indicated that research in psychology on animals could be generalized to humans. Overall, these results suggest that among Spanish psychology students animals research is considered important for the advancement of the science. Likewise, a majority of students displayed positive attitudes toward animal research.

Amarisolide monohydrate, a 2-(beta-glucosyl)neoclerodane

The absolute configuration of the neoclerodane glycoside amarisolide, presented here as the monohydrate, C26H36O9*H2O, has been determined by association with the known configuration of the glucose moiety. Its structure was established as 2beta-(O-beta-D-glucopyranosyl)neocleroda-3,13(16),14-trien-15,16-epoxy-18,19-olide. Extensive hydrogen bonding among the hydroxyl groups of the sugar moiety forms layers which are interconnected by water molecules.

MDMA ("ecstasy") exhibits an anxiogenic-like activity in social encounters between male mice

Recent studies have suggested that 3,4-methylenedioxymethamphetamine (MDMA; "ecstasy"), a synthetic amphetamine derivative, might exhibit an anxiogenic-like activity in rodents. In this work, we examined the effects of MDMA (1, 8 and 15 mg kg(-1), i.p.) on social encounters between male mice using an ethopharmacological approach. Likewise, we compared the behavioural profile of MDMA with that induced by FG 7142 (15 mg kg(-1), i.p.), an anxiogenic benzodiazepine receptor ligand. Individually housed mice were exposed to anosmic standard opponents 30 min after drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. MDMA (8 and 15 mg kg(-1)) produced a behavioural pattern characterized by a marked decrease of aggression (threat and attack) as well as social investigation, body care and digging behaviours, without affecting immobility. Moreover, avoidance/flee and defence/submission behaviours were significantly increased by the drug. A very similar behavioural profile was observed in FG 7142-treated animals. Overall, these findings might indicate that MDMA has anxiogenic-like properties in male mice.

Pathogenesis of Histoplasma capsulatum

Histoplasma capsulatum is well adapted to be infectious and pathogenic for humans. As a soil fungus with no known requirement for interacting with a mammalian host as part of an obligate lifecycle, its plethora of strategies for successful pathogenesis is particularly remarkable. These features include the dimorphic mold-yeast transition, entry into host macrophages, subcellular localization, intracellular survival and proliferation during active infection, and persistence during clinically inapparent infection with the capacity for reactivation. To thrive within the harsh environment of a professionally phagocytic and antimicrobial host cell, H. capsulatum displays mechanisms for modulating its microenvironmental pH level, resisting host reactive oxygen and nitrogen intermediates and degradative enzymes, and withstanding nutrient starvation conditions, including acquisition of iron and calcium and biosynthesis of nucleic acid precursors. Attention has been focused on identifying virulence-associated phenotypic traits and genes that are differentially expressed under relevant conditions, such as yeast morphotype-specific genes and genes that are up-regulated during infection. These studies, together with the increasing ability to perform molecular genetic manipulations in this fungus, may yield novel antifungal drug or vaccine targets as well as elucidating pathogenic mechanisms.

An RNA polymerase II complex containing capping enzymes and viral oncoproteins

The aim of this work was to identify proteins from Adenovirus 2-infected HeLa cell extracts that interact with the carboxyl-terminal domain of the largest subunit of RNA polymerase II. First, a mammalian RNA polymerase II complex was isolated from Adenovirus 2-infected HeLa cell extracts by affinity chromatography against the carboxyl-terminal domain of the largest subunit of RNA polymerase II, followed by chromatography on a Mono S fast protein liquid chromatographic column. Second, the isolated complex was further characterized by Western blot analysis, the formation of a GMP-protein complex, and transcriptional activity. The isolated complex contains general transcription factors, chromatin-remodeling factors, histone acetyltransferases, Srbs, capping enzymes, and E1A viral oncoproteins. The RNA polymerase II complex is active in transcription when supplemented with recombinant transcription factor IIB.

Effects of 3,4-methylenedioxy-methamphetamine (MDMA) on anxiety in mice tested in the light-dark box

1. The effects of acute administration of 3,4-methylenedioxymethamphetamine (MDMA; "ecstasy") on anxiety tested in the light/dark box were examined in albino male mice of the OF.1 strain. 2. Animals were evaluated in the light/dark test 30 min after injection of MDMA (1, 8, and 15 mg/kg, i.p) or saline. The following parameters were recorded (for 5 min); (a) number of exploratory rearings in the light and dark sections; (b) number of transitions between the lit and dark areas; (c) time spent in the light and dark areas; (d) latency of the initial movement from the light to the dark area, and (e) locomotor activity in light area. 3. MDMA (8 and 15 mg/kg) produced a significant reduction in exploratory activity (rearings and transitions), without decreasing motility, in comparison with saline-treated mice. However, time spent in lit/dark compartments was not significantly affected by the drug, which could be a consequence of the anti-exploratory properties of MDMA. 4. Overall, the behavioral profile found in the light/dark test indicates an anxiogenic-like activity of MDMA in mice. It is suggested, however, that animal models of anxiety which emphasize a social interaction could be more sensitive to the effects of this substance.

Effects of N6-cyclohexyl adenosine (CHA) on isolation-induced aggression in male mice

Several studies have suggested adenosine receptor involvement in the modulation of aggressive behavior; however, the influence of adenosine A1 agonists on aggression is scarcely known. In this study, we examined the effect of N6-cyclohexyl adenosine (CHA; 0.025-0.4 i.p.), a selective adenosine A1 receptor agonist, on agonistic behavior elicited by isolation in male mice. Individually housed mice were exposed to anosmic standard opponents 60 min after drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. CHA exhibited an ethopharmacological profile characterized by a selective decrease of offensive behaviors (threat and attack) at the intermediate dose (0.1 mg/kg), without impairment of motor activity. In contrast, the antiaggressive action of the highest doses used (0.2 and 0.4 mg/kg) was accompanied by a marked increase of immobility. It is concluded that the behavioral effects observed in this study could be related to an adenosine modulatory action on other neurotransmitter systems (dopamine/serotonin).

Polystachynes A-E, five cis-neo-clerodane diterpenoids from Salvia polystachya

From the aerial parts of Salvia polystachya five new neo-clerodane diterpenoids, polystachynes A-E, have been isolated. The structures were established by spectroscopic methods, including the X-ray analysis of polystachynes C and D. The known clerodanes salvifaricin, linearolactone and dehydrokerlin were also isolated.

Behavioral profile of quinpirole in agonistic encounters between male mice

Most neuroleptic drugs that act as dopaminergic D2 receptor antagonists are effective antiaggressive agents. Although the action of D2 antagonists on aggression has been extensively documented, little is known about the influence of D2 agonists. This study was designed to examine the effect of quinpirole (0.2, 0.4 and 0.8 mg/kg i.p.), a potent agonist at D2 receptors,on agonistic behavior elicited by isolation in male mice. Individually housed mice were exposed to anosmic standard opponents 30 min after drug administration and encounters were videotaped and evaluated using an ethologically based analysis. Quinpirole exhibited an ethopharmacological profile characterized by a selective decrease in offensive behaviors (threat and attack) at low doses (0.2 mg/kg) without affecting motility or exploratory behaviors. This action could be related to the activation of presynaptic D2 receptors. In contrast, at higher doses (0.8 mg/kg), this drug produced a behavioral pattern defined by a significant increase in defense/submission and avoidance/fleeing as well as a reduction in digging and social investigation behaviors suggesting that it could also show anxiogenic-like properties.

Crystal structure of triosephosphate isomerase from Trypanosoma cruzi in hexane

To gain insight into the mechanisms of enzyme catalysis in organic solvents, the x-ray structure of some monomeric enzymes in organic solvents was determined. However, it remained to be explored whether the structure of oligomeric proteins is also amenable to such analysis. The field acquired new perspectives when it was proposed that the x-ray structure of enzymes in nonaqueous media could reveal binding sites for organic solvents that in principle could represent the starting point for drug design. Here, a crystal of the dimeric enzyme triosephosphate isomerase from the pathogenic parasite Trypanosoma cruzi was soaked and diffracted in hexane and its structure solved at 2-A resolution. Its overall structure and the dimer interface were not altered by hexane. However, there were differences in the orientation of the side chains of several amino acids, including that of the catalytic Glu-168 in one of the monomers. No hexane molecules were detected in the active site or in the dimer interface. However, three hexane molecules were identified on the surface of the protein at sites, which in the native crystal did not have water molecules. The number of water molecules in the hexane structure was higher than in the native crystal. Two hexanes localized at <4 A from residues that form the dimer interface; they were in close proximity to a site that has been considered a potential target for drug design.

Transcriptional functions of a new mammalian TATA-binding protein-related factor

A mammalian protein highly homologous to TATA-binding protein (TBP) has been identified and cloned. The recombinant mammalian TBP-related factor binds to the TATA box of the Ad-MLP and forms stable complexes with TFIIB on the promoter DNA. The mammalian TBP-related factor is able to substitute for TBP in supporting transcription by RNA polymerase II in an in vitro reconstituted system.

Derivatization of the interface cysteine of triosephosphate isomerase from Trypanosoma brucei and Trypanosoma cruzi as probe of the interrelationship between the catalytic sites and the dimer interface

In the interface of homodimeric triosephosphate isomerase from Trypanosoma brucei (TbTIM) and Trypanosoma cruzi (TcTIM), one cysteine of each monomer forms part of the intersubunit contacts. The relatively slow derivatization of these cysteines by sulfhydryl reagents induces progressive structural alterations and abolition of catalysis [Garza-Ramos et al. (1998) Eur. J. Biochem. 253, 684-691]. Derivatization of the interface cysteine by 5, 5-dithiobis(2-nitrobenzoate) (DTNB) and methylmethane thiosulfonate (MMTS) was used to probe if events at the catalytic site are transmitted to the dimer interface. It was found that enzymes in the active catalytic state are significantly less sensitive to the thiol reagents than in the resting state. Maximal protection against derivatization of the interface cysteine by thiol reagents was obtained at near-saturating substrate concentrations. Continuous recording of derivatization by DTNB showed that catalysis hinders the reaction of sulfhydryl reagents with the interface cysteine. Therefore, in addition to intrinsic structural barriers, catalysis imposes additional impediments to the action of thiol reagents on the interface cysteine. In TcTIM, the substrate analogue phosphoglycolate protected strongly against DTNB action, and to a lesser extent against MMTS action; in TbTIM, phosphoglycolate protected against the effect of DTNB, but not against the action of MMTS. This indicates that barriers of different magnitude to the reaction of thiol reagents with the interface cysteine are induced by the events at the catalytic site. Studies with a Cys14Ser mutant of TbTIM confirmed that all the described effects of sulfhydryl reagents on the trypanosomal enzymes are a consequence of derivatization of the interface cysteine.

Behavioral profile of 3,4-methylenedioxy-methamphetamine (MDMA) in agonistic encounters between male mice

1. The effects of acute administration of 3, 4-methylenedioxymethamphetamine (MDMA), a synthetic amphetamine derivative (0.5-20 mg/kg, i.p.) on agonistic behavior elicited by isolation in male mice were examined. 2. Individually housed mice were exposed to anosmic "standard opponents" 30 min after MDMA injection, and the encounters were videotaped and evaluated using an ethologically based analysis. 3. MDMA (5-20 mg/kg) exhibited a behavioral profile characterized by a reduction of aggression (threat and attack) without a concomitant increase of immobility, accompanied by a decrease of social investigation and a increment of exploration from a distance, avoidance/flee and defense/submission behaviors. 4. This ethopharmacological profile might suggest an anxiogenic-like activity of MDMA in albino male mice.

Phosphorylation of yeast TBP by protein kinase CK2 reduces its specific binding to DNA

Protein kinase CK2 is a ubiquitous Ser/Thr kinase which phosphorylates a large number of proteins including several transcription factors. Recombinant Xenopus laevis CK2 phosphorylates both recombinant Saccharomyces cerevisiae and Schizosaccharomyces pombe TATA binding protein (TBP). The phosphorylation of TBP by CK2 reduces its binding activity to the TATA box. CK2 copurifies with the transcription factor IID (TFIID) complex from HeLa cell extracts and phosphorylates several of the TBP-associated factors within TFIID. Taken together these findings argue for a role of CK2 in the control of transcription by RNA polymerase II through the modulation of the binding activity of TBP to the TATA box.

Differences in the intersubunit contacts in triosephosphate isomerase from two closely related pathogenic trypanosomes

The aligned amino acid sequences of TIM from Trypanosoma cruzi (TcTIM) and Trypanosoma brucei (TbTIM) have a positional identity of 68%. The two enzymes have markedly similar catalytic properties. Agents that interact with their interface Cys inhibit TcTIM and TbTIM; and those TIMs that lack this Cys (such as human TIM) are largely or completely insensitive to these agents. The susceptibility of TcTIM to the agents is approximately 100 times higher than that of TbTIM. To ascertain the cause of this large difference, the crystal structure of TcTIM was solved at 1.83 A resolution. The two enzymes are very similar homodimers. In TcTIM and TbTIM their respective Cys, 15 or 14, forms part of the dimer interface. In both, the contacts of the Cys with residues of the other subunit are almost identical. Nevertheless, there are noteworthy differences between the two; the existence of glutamine 18 in TbTIM instead of glutamic acid in TcTIM at the beginning of helix 1 decreases the contacts between this portion of the protein and helix 3 of the other subunit. In addition, TcTIM has proline at position 24 in the first helix of the TIM barrel; this is absent in the other TIM. Pro24 disrupts the regular helix arrangement, making the pitch of this helix 1.2 A longer than in TbTIM. When Pro24 of TcTIM was substituted for Glu, the sensitivity of TcTIM to sulfhydryl reagents increased about fivefold, possibly as a consequence of an increase in the space between the first portion of helix 1 and helix 3 of the other subunit. Therefore, it may be concluded that the geometry of the latter region is central in the accessibility to agents that perturb the interface Cys. In human TIM this region is more compact.

Anti-inflammatory activity of phenyl propanoids from Coreopsis mutica var. mutica

The structures of three phenyl propanoids isolated from the aerial parts of Coreopsis mutica var. mutica were established by spectroscopic analysis as (-)-bornyl p-coumarate, (-)-bornyl ferulate, and (-)-bornyl caffeate. These compounds have been previously isolated from diverse sources. Their complete and assigned 1H- and 13C-NMR data together with an assessment of their anti-inflammatory activities are given.

Anti-inflammatory activity of phenyl propanoids from Coreopsis mutica var. mutica

The structures of three phenyl propanoids isolated from the aerial parts of Coreopsis mutica var. mutica were established by spectroscopic analysis as (-)-bornyl p-coumarate (1), (-)-bornyl ferulate (2), and (-)-bornyl caffeate (3). These compounds have been previously isolated from diverse sources. Their complete and assigned 1H- and 13C-NMR data together with an assessment of their anti-inflammatory activities are given.

Recombinant human mRNA cap methyltransferase binds capping enzyme/RNA polymerase IIo complexes

Guanine N-7 methylation is an essential step in the formation of the m7GpppN cap structure that is characteristic of eukaryotic mRNA 5' ends. The terminal 7-methylguanosine is recognized by cap-binding proteins that facilitate key events in gene expression including mRNA processing, transport, and translation. Here we describe the cloning, primary structure, and properties of human RNA (guanine-7-)methyltransferase. Sequence alignment of the 476-amino acid human protein with the corresponding yeast ABD1 enzyme demonstrated the presence of several conserved motifs known to be required for methyltransferase activity. We also identified a Drosophila open reading frame that encodes a putative RNA (guanine-7-)methyltransferase and contains these motifs. Recombinant human methyltransferase transferred a methyl group from S-adenosylmethionine to GpppG 5'ends, which are formed on RNA polymerase II transcripts by the sequential action of RNA 5'-triphosphatase and guanylyltransferase activities in the bifunctional mammalian capping enzyme. Binding studies demonstrated that the human cap methyltransferase associated with recombinant capping enzyme. Consistent with selective capping of RNA polymerase II transcripts, methyltransferase also formed ternary complexes with capping enzyme and the elongating form of RNA polymerase II.

Tiapride-induced catalepsy is potentiated by gamma-hydroxybutyric acid administration

1. The effect of administration of gammahydroxybutyrate (GHB) and tiapride, either alone or in combination, on catalepsy behavior was examined in male mice. 2. Catalepsy was measured by bar and grid tests. Two successive evaluations were carried out 30 and 60 min after injections. 3. Tiapride (175 and 200 mg/kg) and gammahydroxybutyrate (200 mg/kg) provoked an increase of catalepsy scores, exhibiting different time courses. GHB produced a marked but short lasting catalepsy with a peak of action at 30 min, while tiapride produced a catalepsy state with a peak of action at 60 min. 4. Tiapride-induced catalepsy was potentiated by gammahydroxybutyrate administration at 30 min (bar test) and 60 min (bar and grid tests). 5. These results underlie the view that GHB interacts with central dopamine D2 transmission.

Mammalian capping enzyme complements mutant Saccharomyces cerevisiae lacking mRNA guanylyltransferase and selectively binds the elongating form of RNA polymerase II

5'-Capping is an early mRNA modification that has important consequences for downstream events in gene expression. We have isolated mammalian cDNAs encoding capping enzyme. They contain the sequence motifs characteristic of the nucleotidyl transferase superfamily. The predicted mouse and human enzymes consist of 597 amino acids and are 95% identical. Mouse cDNA directed synthesis of a guanylylated 68-kDa polypeptide that also contained RNA 5'-triphosphatase activity and catalyzed formation of RNA 5'-terminal GpppG. A haploid strain of Saccharomyces cerevisiae lacking mRNA guanylyltransferase was complemented for growth by the mouse cDNA. Conversion of Lys-294 in the KXDG-conserved motif eliminated both guanylylation and complementation, identifying it as the active site. The K294A mutant retained RNA 5'-triphosphatase activity, which was eliminated by N-terminal truncation. Full-length capping enzyme and an active C-terminal fragment bound to the elongating form and not to the initiating form of polymerase. The results document functional conservation of eukaryotic mRNA guanylyltransferases from yeast to mammals and indicate that the phosphorylated C-terminal domain of RNA polymerase II couples capping to transcription elongation. These results also explain the selective capping of RNA polymerase II transcripts.

Acceleration of unisite catalysis of mitochondrial F1-adenosinetriphosphatase by ATP, ADP and pyrophosphate--hydrolysis and release of the previously bound [gamma-32P]ATP

The effect of ATP, ADP and pyrophosphate (PPi) on hydrolysis and release of [gamma-32P]ATP bound to the high-affinity catalytic site of soluble F1 from bovine heart mitochondria under unisite conditions [Grubmeyer, C., Cross, R. L. & Penefsky, H. S. (1982) J. Biol. Chem. 257, 12092-12100] was studied. In accord with the previous data, it was observed that millimolar concentrations of ATP or ADP added to F1 undergoing unisite hydrolysis of [gamma-32P]ATP accelerated its hydrolysis. PPi also produced a hydrolytic burst of a fraction of the previously bound [gamma-32P]ATP; kinetic data suggested that for production of optimal hydrolysis by PPi of the bound [gamma-32P]ATP, two binding sites with apparent Kd of 27 microM and 240 microM must be filled. The extent of the hydrolytic burst induced by MgPPi was lower than that induced by ADP and ATP. In F1 in which PPi had produced a hydrolytic burst of the bound [gamma-32P]ATP, the addition of ATP induced a second burst of hydrolysis. By filtration experiments and enzyme trapping, it was also studied whether ATP, ADP and PPi produce release of the tightly bound [gamma-32P]ATP. At millimolar concentrations, ATP and ADP brought about release of about 25% of the previously bound [gamma-32P]ATP. At micromolar concentrations, ADP accelerated the hydrolysis of the previously bound [gamma-32P]ATP but not its release. Hence, the hydrolytic and release reactions could be separated, indicating that the two reactions require the occupancy of different sites in F1. With PPi, no release of the tightly bound [gamma-32P]ATP was observed. The ADP induced hydrolysis and release of the F1-bound [gamma-32P]ATP were inhibited by sodium azide to the same extent (60%). Since release of ATP from a high-affinity catalytic site of F1 represents the terminal step of oxidative phosphorylation, the data illustrate that the binding energy of substrates to F1 is critical to the ejection of ATP into the media. The failure of PPi to induce release of [gamma-32P]ATP bound to F1 under unisite conditions is probably due to its lower binding energy.