Assembly of mitochondria

The majority of mitochondrial proteins are synthesized on cytoplasmic ribosomes and transferred to the mitochondria where they are assembled to supramolecular structures. The intracellular transfer of these proteins appears to occur by a post-translational mechanism, i.e., it involves extramitochondrial precursor forms which are translocated in a step independent from translation. The synthesis and transfer of individual proteins was investigated in vivo, or in vitro employing homologous and heterologous cell free systems for protein synthesis. Cytochrome c was initially made as the apoprotein. This precursor protein was converted to the holoprotein on uptake by mitochondria in reconstituted systems. Integrity of mitochondria was essential for the apo to holo conversion. In the case of the ADP/ATP carrier protein, an integral transmembrane protein of the inner mitochondrial membrane, the initial translation product had the same apparent molecular weight as the mature protein. It was found in soluble form in the post-ribosomal supernatant. Citrate synthase, a matrix protein, was synthesized as a precursor with an apparent molecular weight of 47 000. Transfer to the mitochondria was accompanied by cleavage to yield a molecular weight of 45 000. The significance of these results in relation to the mechanisms of intracellular transfer and of assembly of the individual proteins is discussed

The effect of substrate stability and canopy cover on macroinvertebrate communities in Taranaki ring plain streams : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Ecology at Massey University

The relative effect of substrate stability and canopy cover on macroinvertebrate communities, and their possible interaction, were investigated in 10 Taranaki ring plain streams between April 1999 and March 2000. Substrate stability was examined as it is postulated to be the major influencing factor on stream invertebrates and canopy cover as it will effect periphyton, a major invertebrate food source. Invertebrate communities, periphyton biomass and stone movement were monitored at 20 sites on these Streams of differing hydrological regime, a closed canopy site and an open canopy site on each stream. Macroinvertebrate species richness and periphyton grazer abundance were higher in open canopy sites than closed canopy sites and this was probably related to periphyton biomass which was higher at the open sites. Species richness displayed a strong quadratic relationship with periphyton biomass and overall macroinvertebrate community composition also appeared to be related to levels of periphyton as dictated by canopy cover. However this effect was overridden by substrate stability when disturbance levels were high. The effect of substrate stability and cover was also examined in an experiment, in one of the 10 streams; Cold Stream, where both factors could be independently manipulated. Wire mesh substrate baskets which were subjected to either artificial disturbance or left undisturbed were used under an artificial cover. Cover was found to influence invertebrate community composition, probably via its effect on periphyton biomass, while physical disturbance decreased both invertebrate abundance and diversity. Keywords: substrate stability; canopy cover; disturbance; productivity; macroinvertebrates; periphyton; community structure; diversity

Does gender matter in doctor-patient communication during standard gynaecological consultations? : an analysis using mixed methods

This paper assesses whether gender plays a role when male and female participants discuss the quality of doctor\u2013patient communication in gynaecological consultations. A European multi-centre study was conducted comprising 259 participants in 35 gender- and country-specific focus groups. In all focus groups, a set of four videotaped Objective Structured Clinical Examination (OSCE) consultations was used as a prompt for discussion. The doctors\u2019 ability in communication was assessed by participants\u2019 ratings and by a quantified content analysis of their comments, using a mixed-method approach. Gender analysis was performed applying a set of generalized linear regression models. The findings indicated that gender differences were smaller than expected. The individual ratings of the overall quality of communication were similar for male and female participants, and there were hardly any differences in the content of the discussions. The only two exceptions were that female doctors were criticized more than male doctors when they made impersonal comments and that female participants were more outspoken than men, positively and negatively. The prevalence of gender similarities suggests that doctors\u2019 empathy, support, understanding and pleasantness are highly appreciated by both male and female participants and appear to transcend gender differences