Progesterone and insulin stimulation of CPEB-dependent polyadenylation is regulated by Aurora A and glycogen synthase kinase-3

Progesterone stimulation of Xenopus oocyte maturation requires the cytoplasmic polyadenylation-induced translation of mos and cyclin B mRNAs. One cis element that drives polyadenylation is the CPE, which is bound by the protein CPEB. Polyadenylation is stimulated by Aurora A (Eg2)-catalyzed CPEB serine 174 phosphorylation, which occurs soon after oocytes are exposed to progesterone. Here, we show that insulin also stimulates Aurora A-catalyzed CPEB S174 phosphorylation, cytoplasmic polyadenylation, translation, and oocyte maturation. However, these insulin-induced events are uniquely controlled by PI3 kinase and PKC-zeta, which act upstream of Aurora A. The intersection of the progesterone and insulin signaling pathways occurs at glycogen synthase kinase 3 (GSK-3), which regulates the activity of Aurora A. GSK-3 and Aurora A interact in vivo, and overexpressed GSK-3 inhibits Aurora A-catalyzed CPEB phosphorylation. In vitro, GSK-3 phosphorylates Aurora A on S290/291, the result of which is an autophosphorylation of serine 349. GSK-3 phosphorylated Aurora A, or Aurora A proteins with S290/291D or S349D mutations, have reduced or no capacity to phosphorylate CPEB. Conversely, Aurora A proteins with S290/291A or S349A mutations are constitutively active. These results suggest that the progesterone and insulin stimulate maturation by inhibiting GSK-3, which allows Aurora A activation and CPEB-mediated translation.     

Increased seminal plasma lead levels adversely affect the fertility potential of sperm in IVF

BACKGROUND: Lead remains in high levels in the environment and is known to reduce fertility in animal models, but a direct link between lead exposures and human infertility has not yet been established. METHODS: In a prospective, double-blind study of the metal ion levels and sperm function, semen was obtained from partners of 140 consecutive women undergoing their first IVF cycle. Lead in seminal plasma was determined by atomic absorption spectroscopy. Motile sperm populations were assessed for surface receptors for mannose binding, and the ability to undergo premature ('spontaneous'), and free mannose-induced acrosome reactions. Fertile donor (n = 9) sperm were exposed to exogenous lead during capacitating incubations and then assessed for mannose receptor expression and acrosome loss. RESULTS: Lead levels were negatively correlated with IVF rates. Lead levels were negatively correlated to two of the three sperm function biomarkers (mannose receptors, mannose-induced acrosome reactions). Lead levels positively correlated with the spontaneous acrosome reaction. These findings were mimicked by in-vitro exposure of fertile donor sperm to lead. CONCLUSIONS: Multiple sperm parameters are affected as lead levels rise. Increased lead levels may contribute to the production of unexplained male infertility.     

Global molecular epidemiology of the O15:K52:H1 extraintestinal pathogenic Escherichia coli clonal group: evidence of distribution beyond Europe

Escherichia coli O15:K52:H1 is a significant extraintestinal pathogen in Europe (G. Prats et al., J. Clin. Microbiol. 38:201-209, 2000). To search for evidence of this clonal group outside of Europe, 75 non-European E. coli isolates of serogroup O15 were compared with five members of the O15:K52:H1 clonal group from Barcelona, Spain, according to genomic background, virulence genotypes, and antimicrobial resistance profiles. Amplification phylotyping showed that 16 (21%) of the 75 non-European O15 isolates corresponded with the O15:K52:H1 clonal group. The 16 non-European O15:K52:H1 clonal group members represented diverse geographic locales. They were isolated almost exclusively from humans with extraintestinal infections and accounted for 50% of all O15 isolates from five human clinical collections studied. Most non-European clonal group members exhibited a consensus virulence factor profile that included the F16 or F7-2 papA alleles (P fimbrial structural subunit), papG allele II (P fimbrial adhesin), iha (putative adhesin siderophore), and iutA (aerobactin receptor). This resembles the virulence profiles of (i) European representatives of the O15:K52:H1 clonal group and (ii) phylogenetically related "clonal group A," a recently recognized significant contributor to trimethoprim-sulfamethoxazole resistance in the United States (A. R. Manges et al., N. Engl. J. Med. 345:1007-1013, 2001). Antimicrobial resistance profiles were variable, and resistance was inconsistently transferred by conjugation. These findings indicate that the O15:K52:H1 clonal group is broadly distributed beyond Europe, exhibits previously unrecognized phenotypic and genotypic diversity, and contributes significantly to extraintestinal infections in humans.     

Enhanced molecular volume of conservatively pegylated Hb: (SP-PEG5K)6-HbA is non-hypertensive

Recent studies have suggested that the "pressor effect" of acellular Hb is a consequence of perturbation of the macro-and microcirculatory system in multiple ways, and that PEGylation is an effective approach for controlling the same. In an attempt to confirm this concept, a new and simple thiolation mediated, maleimide chemistry-based conservative PEGylation protocol has been developed to conjugate multiple copies of PEG-chains to Hb. This approach combines the high reactivity of maleimides towards thiols with the propensity of iminothiolane to derivatize the epsilon-amino groups of proteins into reactive thiol groups, with conservation of their positive charge. One of the PEGylated products, namely (SP-PEG5K)6-HbA, that carries on an average six copies of PEG5000 chains per Hb, is non-hypertensive in hamster top load and in rat 50% exchange transfusion models. This hexa-PEGylated-Hb has (i) a hydrodynamic volume corresponding to that of an oligomerized Hb of 256kDa, (ii) a molecular radius of approximately 6.8 nm, (iii) high oxygen affinity, (iv) lowered Bohr effect, and (v) increased viscosity and colloidal osmotic pressure. These properties of (SP-PEG5K)6-HbA are consistent with the emerging new paradigms for the design of Hb based oxygen carriers and confirm the concept that the "pressor effect" of Hb is a multifactorial event. The thiolation mediated maleimide chemistry-based PEGylation protocol described here for the generation of (SP-PEG5K)6-Hb is simple, highly efficient, and is carried out under oxy conditions. The results demonstrate that a non-hypertensive PEG-Hb can be generated by conjugation of a lower number of PEG chains than previously reported.     

Monoclonal antibodies against Enterocytozoon bieneusi of human origin

Enterocytozoon bieneusi is clinically the most significant among the microsporidia infecting humans, causing chronic diarrhea, wasting, and cholangitis in individuals with human immunodeficiency virus/AIDS. The lack of immune reagents is largely due to the absence of methods for laboratory propagation of E. bieneusi. We recently described a procedure for the concentration and purification of spores from diarrheic stool of infected humans. Purified spores were used to immunize mice for production and screening of monoclonal antibodies (MAbs) against E. bieneusi. The eight immunoglobulin M MAbs generated and fully characterized did not cross-react with other human microsporidia or with other microorganisms normally present in stool. One of the MAbs, 2G4, reacted with E. bieneusi spores in stools from monkeys and humans, without background fluorescence, which makes it an ideal diagnostic reagent. It also recognizes intracellular stages of the parasite and will be suitable for determining tissue distribution of E. bieneusi in infected hosts. At least two immunodominant antigens of E. bieneusi of 33,000 and 35,000 Da exist, which were recognized by rabbit and mouse antisera. The availability of MAbs against E. bieneusi will simplify considerably the diagnosis of this infection in humans and will provide tools for epidemiologic investigations regarding the true prevalence of the infection in various human and mammalian populations and the environmental sources of infection.     

Primitive Neuroectodermal Tumors of the Central Nervous System

Controversial issues relating to the pathobiology and classification of central nervous system primitive neuroectodermal tumors (PNETs) have plagued neuropathologists for more than 70 years. Hypotheses advanced in the mid-1920's have remained as fixed concepts in contemporary literature, largely consequent to repetitious support by a small number of neuropathologists despite a growing body of information discrediting these ideas from neuroembryologists, oncologists, neuroscien-tists and pathologists.
Attention has largely focused upon PNETs arising in the cerebellum (commonly known as medul-loblastomas [MBs]), because about 80% of central nervous system (CNS) PNETs originate in this site. It has been asserted that the 20% which do not are biologically different, although most individuals agree that the histological features of PNETs that occur in different sites throughout the CNS are indistinguishable from those growing in the cerebellum.
The historical aspects of this controversy are examined in the face of evidence that there is, in fact, a unique class of CNS tumors which should appropriately be regarded as primitive neuroectodermal in nature. Specifically, a number of different approaches to the problem have yielded data supporting this hypothesis. These approaches include the identification of patterns of expression among a variety of cellular antigens (demonstrated by the use of immunopathological techniques), molecular analyses of cell lines derived from these tumors, experimental production of PNETs and molecular genetic analyses.
Differences of opinion among surgeons, oncologists and radiotherapists are typically resolved by conducting cooperative studies of patients with these tumors who are diagnosed and treated at multiple centers.     

Client choice of treatment and client outcomes

Participants in this study suffered from severe mental illness and were homeless at baseline. They were given their choice of five different treatment programs. The current study investigated two major questions: (1) what is the impact of positive expectancies about the efficacy of the chosen program on number of contacts with the chosen program and client outcomes; and (2) what is the impact of positive views about nonchosen programs (alternative choice variables) on contact with the chosen program and client outcomes. Client outcomes assessed were psychotic symptoms, days homeless, and client satisfaction. Positive expectancy variables were the number of reasons for choosing a program and confidence that the program would help. Alternative choice variables were the number of nonchosen programs visited and the attractiveness of a nonchosen program. Only the number of reasons for choosing the program was significantly related to program contact with the chosen program. Both of the positive expectancy variables and program contact were significantly correlated with consumer satisfaction. In general, neither the positive expectancy variables nor the alternative choice variables predicted changes in psychotic symptoms nor days homeless. © 2003 Wiley Periodicals, Inc. J Comm Psychol 31: 339–348, 2003.     

Regulated CPEB phosphorylation during meiotic progression suggests a mechanism for temporal control of maternal mRNA translation

CPEB is an mRNA-binding protein that stimulates polyadenylation-induced translation of maternal mRNA once it is phosphorylated on Ser 174 or Thr 171 (species-dependent). Disruption of the CPEB gene in mice causes an arrest of oogenesis at embryonic day 16.5 (E16.5), when most oocytes are in pachytene of prophase I. Here, we show that CPEB undergoes Thr 171 phosphorylation at E16.5, but dephosphorylation at the E18.5, when most oocytes are entering diplotene. Although phosphorylation is mediated by the kinase aurora, the dephosphorylation is due to the phosphatase PP1. The temporal control of CPEB phosphorylation suggests a mechanism in which CPE-containing mRNA translation is stimulated at pachytene and metaphase I.     

Coping strategies,hostility, and depressive symptoms: A path model

Previous studies of coping, hostility, and depressive symptoms have highlighted the significant relations between all possible pairs of these 3 variables. To more completely explore the nature of depressive symptoms, we link them all together in this study by testing a coping→hostility→depressive symptoms path model. One hundred forty participants completed psychological questionnaires measuring coping strategies, hostility, and depressive symptoms. While controlling age and social class as covariates, SPSS stepwise regression analyses were used to examine relations among these 3 constructs. Results suggest that coping has a direct relation with depressive symptoms as well as an indirect relation mediated by hostility. Passive coping may lead to increased hostility, resulting in depressive symptoms. Active coping may have the opposite effect. These findings suggest that the inclusion of measures of both coping strategies and hostility yields a more thorough understanding of concomitants of depressive symptoms. From a clinical perspective, knowing what coping strategies a person uses and how much anger they experience and express may be useful in guiding the management of depressive symptoms.