title: Myths and Methodologies: Reducing scientific design ambiguity in studies comparing sexes and/or menstrual cycle phases

authors: Sims, Stacy

subjects: Science & Technology

abstract: In recent years, the increase in scientific literature exploring sex differences has been beneficial to both clinicians and allied health science professionals, although female athletes are still significantly under‐represented in sport and exercise science research. Women have faced exclusion throughout history though the complexities of sociocultural marginalization and biomedical disinterest in women's health. These complexities have contributed to challenges of studying women and examining sex differences. One underlying complexity to methodological design may be hormonal perturbations of the menstrual cycle. The biphasic responses of oestrogen and progesterone across the menstrual cycle significantly influence physiological responses, which contribute to exercise capacity and adaptation in women. Moreover, oral contraceptives add complexity through the introduction of varying concentrations of circulating exogenous oestrogen and progesterone, which may moderate physiological adaptations to exercise in a different manner to endogenous ovarian hormones. Thus, applied sport and exercise science research focusing on women remains limited, in part, by poor methodological design that does not define reproductive status. By highlighting specific differences between phases with regard to hormone perturbations and the systems that are affected, methodological inconsistencies can be reduced, thereby improving scientific design that will enable focused research on female athletes in sports science and evaluation of sex differences in responses to exercise. The aims of this review are to highlight the differences between endogenous and exogenous hormone profiles across a standard 28–32 day menstrual cycle, with the goal to improve methodological design for studies exploring sex differences, menstrual cycle phase differences and/or endogenous versus exogenous female sex hormones.

text: Myths and Methodologies: Reducing scientific design ambiguity in studies comparing sexes and/or menstrual cycle phases In recent years, the increase in scientific literature exploring sex differences has been beneficial to both clinicians and allied health science professionals, although female athletes are still significantly under‐represented in sport and exercise science research. Women have faced exclusion throughout history though the complexities of sociocultural marginalization and biomedical disinterest in women's health. These complexities have contributed to challenges of studying women and examining sex differences. One underlying complexity to methodological design may be hormonal perturbations of the menstrual cycle. The biphasic responses of oestrogen and progesterone across the menstrual cycle significantly influence physiological responses, which contribute to exercise capacity and adaptation in women. Moreover, oral contraceptives add complexity through the introduction of varying concentrations of circulating exogenous oestrogen and progesterone, which may moderate physiological adaptations to exercise in a different manner to endogenous ovarian hormones. Thus, applied sport and exercise science research focusing on women remains limited, in part, by poor methodological design that does not define reproductive status. By highlighting specific differences between phases with regard to hormone perturbations and the systems that are affected, methodological inconsistencies can be reduced, thereby improving scientific design that will enable focused research on female athletes in sports science and evaluation of sex differences in responses to exercise. The aims of this review are to highlight the differences between endogenous and exogenous hormone profiles across a standard 28–32 day menstrual cycle, with the goal to improve methodological design for studies exploring sex differences, menstrual cycle phase differences and/or endogenous versus exogenous female sex hormones.

year: 2018

title: Stable isotope probing: Technical considerations when resolving ¹⁵N-labeled RNA in gradients

authors: Addison, Sarah Louise

subjects: bacteria

abstract: RNA based stable isotope probing (SIP) facilitates the detection and identification of active members of microbial populations that are involved in the assimilation of an isotopically labeled compound. ¹⁵N-RNA-SIP is a new method that has been discussed in recent literature but has not yet been tested. Herein, we define the limitations to using ¹⁵N-labeled substrates for SIP and propose modifications to compensate for some of these shortcomings. We have used ¹⁵N-RNA-SIP as a tool for analysing mixed bacterial populations that use nitrogen substrates. After incubating mixed microbial communities with ¹⁵N-ammonium chloride or ¹⁵N₂ we assessed the fractionation resolution of ¹⁵N-RNA by isopycnic centrifugation in caesium trifluoroacetate (CsTFA) gradients. We found that the more isotopic label incorporated, the further the buoyant density (BD) separation between ¹⁵N- and ¹⁴N-RNA, however it was not possible to resolve the labeled from unlabeled RNA definitively through gradient fractionation. Terminal-restriction fragment length polymorphism (T-RFLP) analysis of the extracted RNA and fluorescent in situ hybridisation (FISH) analysis of the enrichment cultures provided some insight into the organisms involved in nitrogen fixation. This approach is not without its limitations and will require further developments to assess its applicability to other nitrogen-fixing environments.

text: Stable isotope probing: Technical considerations when resolving ¹⁵N-labeled RNA in gradients RNA based stable isotope probing (SIP) facilitates the detection and identification of active members of microbial populations that are involved in the assimilation of an isotopically labeled compound. ¹⁵N-RNA-SIP is a new method that has been discussed in recent literature but has not yet been tested. Herein, we define the limitations to using ¹⁵N-labeled substrates for SIP and propose modifications to compensate for some of these shortcomings. We have used ¹⁵N-RNA-SIP as a tool for analysing mixed bacterial populations that use nitrogen substrates. After incubating mixed microbial communities with ¹⁵N-ammonium chloride or ¹⁵N₂ we assessed the fractionation resolution of ¹⁵N-RNA by isopycnic centrifugation in caesium trifluoroacetate (CsTFA) gradients. We found that the more isotopic label incorporated, the further the buoyant density (BD) separation between ¹⁵N- and ¹⁴N-RNA, however it was not possible to resolve the labeled from unlabeled RNA definitively through gradient fractionation. Terminal-restriction fragment length polymorphism (T-RFLP) analysis of the extracted RNA and fluorescent in situ hybridisation (FISH) analysis of the enrichment cultures provided some insight into the organisms involved in nitrogen fixation. This approach is not without its limitations and will require further developments to assess its applicability to other nitrogen-fixing environments.

year: 2010-01

title: Maori goddesses in literature. Part 2: 1900-1940

authors: Yates-Smith, Aroha

subjects: Atua wāhine

abstract: Many contemporary Māori are familiar with atua wāhine, Māori goddesses, through accounts that have been passed on to them by word of mouth. Few, however, have had an opportunity to consult accounts of atua wāhine that date from the early period of Māori-Pākehā contact. Those who wish to do so may have considerable difficulty in sifting through all of the written materials for the information they seek. For this reason, this paper provides a review of the literature pertaining to atua wāhine from 1900 to 1940, together with a commentary on the sources to which reference is made. A review of literature on atua wāhine from 1880 – 1900 appeared in the first issue of this Journal. The period 1940 towards 2000 will be reviewed in the next issue.

text: Maori goddesses in literature. Part 2: 1900-1940 Many contemporary Māori are familiar with atua wāhine, Māori goddesses, through accounts that have been passed on to them by word of mouth. Few, however, have had an opportunity to consult accounts of atua wāhine that date from the early period of Māori-Pākehā contact. Those who wish to do so may have considerable difficulty in sifting through all of the written materials for the information they seek. For this reason, this paper provides a review of the literature pertaining to atua wāhine from 1900 to 1940, together with a commentary on the sources to which reference is made. A review of literature on atua wāhine from 1880 – 1900 appeared in the first issue of this Journal. The period 1940 towards 2000 will be reviewed in the next issue.

year: 2001-02