Profiling of the secretome of human cancer cells: Preparation of supernatant for proteomic analysis

Secretomic analysis requires removal of serum proteins from cell-culture media. We evaluate the proteins washed from cells prepared in bovine serum-supplemented medium. PBS and serum-free-medium (SFM) were the washing solutions. A Bradford assay was used for total protein concentration and a 1D gel and LC-MS/MS, to assign the protein to human or bovine origin. For both wash solutions, all bovine protein had been removed by the third wash, without compromising the number of living cells. Further washes reduced the number of living cells, especially when using PBS. Proteomic analysis of wash supernatant showed that SFM induced greater lysis of dead cells. Three washes were sufficient to minimize the effects on cell viability, while still removing serum proteins. Washing in SFM resulted in contamination of the wash supernatant with lysed dead cell proteins. Washed cells were incubated in SFM and exposed to ionizing radiation. Analysis of the supernatant showed an increase in human cytoplasmic, plasma membrane, and nuclear protein following irradiation. Secreted proteins were also detected, but in smaller quantities. The significance of these findings extend to in vitro studies of bystander phenomena, since the proteins of lysed dead cells may participate in driving bystander responses

Limonite – a weathered residual soil heterogeneous at all scales

Limonite is a residual soil produced by the decomposition of magnesium silicate (olivine) rocks in tropical environments. During weathering most of the original rock is leached away leaving only its iron content, which is precipitated out in the form of iron sesqui-oxides to create a soft and highly porous soil. The predominant mineral present in limonite is goethite, which forms acicular nanoparticles that agglomerate to produce a silty sand with porous particles. The void ratio varies from 2 to 6, with higher values being a consequence of structure-supported voids. An extensive set of laboratory tests have been performed on a limonite soil profile which extends 50 m to rock. These data show that there is no pattern to shear strength with depth, with the shear strength equally likely to be 50 or 200 kPa through much of the profile. It is argued that the shear strength parameters for failure mechanisms, having any significant length, should be based on average values. The letter presents scanning electron microscopy photographs showing the fundamental particles, the results of triaxial tests comparing natural and reconstituted behaviour which show the effects of microstructure on the meso-scale response, and field data to show site variability

Sensitivity of spermatogonia to irradiation varies with age in pre-pubertal ram lambs

Although germ cells from donor rams transplanted into irradiated recipient testes have produced donor derived offspring, efficiency is low. Further optimization of recipient irradiation protocols will add precision to the depletion of recipient spermatogonia prior to germ cell transplant. Three irradiation doses (9,12,15 Gy) were administered to ram lambs aged 14 weeks (Group 1) and 20 weeks (Group 2), then testicular biopsies were collected 1, 2 and 3 months after irradiation. At 1 month after irradiation of Group 1, only the largest dose (15 Gy) reduced spermatogonia numbers below 10% of non-irradiated controls, whereas in Group 2 lambs, each irradiation dose reduced spermatogonia below 10% of controls. In both Groups, fewer differentiated germ cells were present in seminiferous tubules compared to controls. At 2 months after irradiation, spermatogonia numbers in both Groups increased more than sixfold to be similar to controls, whereas fewer differentiated germ cells were present in the tubules of both Groups. At 3 months in Group 1, each irradiation dose reduced spermatogonia numbers t

Women and men in the Australasian College of Physical Scientists and Engineers in Medicine: workforce survey

A survey was designed to determine aspirations, motivations and workplace experiences of both female and male members of the Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM). The survey collected both quantitate and qualitative data, including open ended questions. This paper reports the survey's qualitative results. The research was approved by Ethics at University of South Australia and endorsed by ACPSEM. All 205 women (30% of total membership) and 440 men were invited to complete the survey online. The data for the qualitative analysis were responses to open-ended questions within the survey. 102 women and 150 men completed surveys were received, with 66 surveys analysed, before data saturation was reached. The survey revealed a number of themes that reflect concerns and opportunities identifying the direction for improving work-life balance and gender equity within the medical physics profession in Australasia. Issues around managing challenging workloads and professional development were amplified for women with children and child-rearing responsibilities, directly contributing to a reduction in work capacity and a reorientation of work-life priorities. The survey provides direction for strategies to improve work-life balance and enable equitable engagement in the profession. The first is to identify and develop role models that actively model successful work-life balance and flexibility in gender roles and in professional conduct. The second is to improve the management skills of current and emerging administrators, advocating for improved work conditions for medical physics professionals at an organisation level. Finally, efforts need to be made to establish flexible professional development and career progression opportunities amongst those that are unable to commit to large workloads, which is common for those with child-rearing responsibilities. The realisation of these strategic goals will reduce the identified barriers to full female participation in the workforce, and shift gender-based subcultures within the workplace.Eva Bezak, Roksolana Suchowerska, Elizabeth Claridge Mackonis, Heath Pillen, Anna Ralston, Annette Haworth, Natalka Suchowersk