Steroid-induced oocyte maturation in Indian shad Tenualosa ilisha (Hamilton, 1822) is dependent on phosphatidylinositol 3 kinase but not MAP kinase activation
Authors: Puja Pal
Sujata Roy Moulik
Sudipta Paul
Dilip Mukherjee
Buddhadev Mallick
Sourav Kundu
Kousik Pramanick
Journal: Molecular and Cellular Endocrinology (2014)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: 17,20Œ≤-P; MAP kinase; Oocyte maturation; PI3 kinase; Tenulosa ilisha
Affiliations: Department of Zoology, Presidency University, 86/1 College Street, Kolkata 73, India., Department of Physiology and Biophysics, School of Medicine, Health Sciences Center-A, University of Louisville, KY 40292, USA., Endocrinology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India., Endocrinology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India. Electronic address: .

Abstract:  Fully grown fish and amphibian oocytes exposed to a maturation-inducing steroid (MIS) activates multiple signal transduction pathways, leading to formation and activation of maturation-promoting factor (MPF) and induction of germinal vesicle breakdown (GVBD). The present study was to investigate if phosphatidylinositol 3 kinase (PI3 kinase) and mitogen-activated protein kinase (MAP kinase) activation are required for naturally occurring MIS, 17Œ±,20Œ≤-dihydroxy-4-pregnen-3-one (17,20Œ≤-P)-induced cdc2 activation and oocyte maturation (OM) in Tenualosa ilisha. We observed that 17,20Œ≤-P-induced OM was significantly inhibited by PI3 kinase inhibitors Wortmannin and LY29400. 17,20 Œ≤-P was shown to activate PI3 kinase maximally at 90 min and cdc2 kinase at 16 h of treatment. Relative involvement of PI3 kinase, MAP kinase and cdc2 kinase in 17,20Œ≤-P-induced OM was examined. MAP kinase was rapidly phosphorylated and activated (60-120 min) after MIS treatment and this response preceded the activation of cdc2 kinase by several hours. A selective inhibitor of MAP kinase (MEK), PD98059, sufficiently blocked the phosphorylation and activation of MAP kinase. Inhibition of MAP kinase activity using PD98059 however, had no effect on MIS-induced cdc2 kinase activation and GVBD. These results demonstrate that activation of the PI3 kinase is required for 17,20Œ≤-P-induced cdc2 kinase activation and OM in T. ilisha. MAP kinase although was activated in response to 17,20Œ≤-P and PI3 kinase activation, it is not necessary for cdc2 activation and OM in this species. 

Retracted: No

PubPeer comments:
 This article was reviewed on the error bar podcast episode 3: https: theerrorbar.com ?e=3. The review was done in the light of newspaper headlines about the article. The slightly-edited transcript is copied here: headline: LANGUAGE LEAKS LOST LOVE tweet: thousands of reddit users posts were analysed for signs of their impending relationship break-ups. they were a bit less analytical than usual, said i and we a bit more. love hurts. description: the Mail and the Times report on a study of the language people use when they are about to go through a breakup. the study by psychologists in Texas, USA used computer text mining to analyse more than a million posts on the social media site Reddit, in a particular subsection about relationship break ups. the text analysis identified a decrease in the use of analytical - or problem-solving - thinking, increases in more emotional cognitive processing, and increased use of the personal pronouns I and we . the authors claim that such methods help understand the emotional upheavals of relationship breakups; the newspapers claim that people about to break up change the way they speak. evaluation: while the headlines state that we can use our partner s language to warn us of an impending breakup, the evidence is not so clear-cut. first, this study used the large, freely-available dataset of Reddit, a social media site on which all users and posts are public and can be fully anonymous. none of the users, relationships, or stories were, or can be, verified for truthfulness. and they were dredged for data. second, the researchers targeted a section of the site called BreakUps. and they only looked at users who went to that site for the first time, presumably to post about their relationship break up. third, the authors assumed that the time of the first post was also the time of the breakup. they only actually read two hundred of the 1,027,541 posts. of those 200, only 121 gave an indication of the break-up time, and of them, the majority - 98 - said it was within the previous 2 weeks. so, fewer than half of the relatively small sample of posts said that the breakup was recent. so any claims that language can predict break ups are impossible to verify. fourth, while the headlines and claims are about people in general, two thirds of Reddit users are male, and typically young. this is reflected in the very patchy and unreliable demographics of the study participants : an estimated 70% were male, 67% had been dumped, the average age was 23, and average relationship length was 2 years. fifth, despite containing millions of datapoints, dozens of variables tested, and looking at each variable over every single 2-week period over 2 years, there is no proper treatment of the statistical problems of false-positives - due to many tests being done - or of auto-correlation - the fact that the same people are providing data at many different time-points, and the number of people changes at each time-point. finally, even if the results stand up, the introduction contains contradictory predictions about the usefulness of the analytic type of thinking - the authors predicted on page 1 that people deciding to leave a relationship should increase their analytical thinking, but on page 2 that people will decrease their analytic thinking as a breakup occurs. page 2 lists a long  set of hypotheses that are all a little vague. who starts a study with a whole set of hypotheses? overall: this study seems a bit like a fishing expedition. conclusion: a self-selected group - largely of anonymous young men who have been dumped - make their first post on a social media site about break ups. the posts are not very analytical say I we a lot. ,