In utero exposure to low doses of environmental pollutants disrupts fetal ovarian development in sheep

Epidemiological studies of the impact of environmental chemicals on reproductive health demonstrate consequences of exposure but establishing causative links requires animal models using ‘real life’ in utero exposures. We aimed to determine whether prolonged, low-dose, exposure of pregnant sheep to a mixture of environmental chemicals affects fetal ovarian development. Exposure of treated ewes (n = 7) to pollutants was maximized by surface application of processed sewage sludge to pasture. Control ewes (n = 10) were reared on pasture treated with inorganic fertilizer. Ovaries and blood were collected from fetuses (n = 15 control and n = 8 treated) on Day 110 of gestation for investigation of fetal endocrinology, ovarian follicle/oocyte numbers and ovarian proteome. Treated fetuses were 14% lighter than controls but fetal ovary weights were unchanged. Prolactin (48% lower) was the only measured hormone significantly affected by treatment. Treatment reduced numbers of growth differentiation factor (GDF9) and induced myeloid leukaemia cell differentiation protein (MCL1) positive oocytes by 25–26% and increased pro-apoptotic BAX by 65% and 42% of protein spots in the treated ovarian proteome were differently expressed compared with controls. Nineteen spots were identified and included proteins involved in gene expression/transcription, protein synthesis, phosphorylation and receptor activity. Fetal exposure to environmental chemicals, via the mother, significantly perturbs fetal ovarian development. If such effects are replicated in humans, premature menopause could be an outcome

In situ observation of structural changes in polycrystalline silver catalysts by environmental scanning electron microscopy

Morphology changes induced in polycrystalline silver catalysts as a result of heating in either oxygen, water or oxygen-methanol atmospheres have been investigated by environmental scanning electron microscopy (ESEM), FT-Raman spectroscopy and temperature programmed desorption (TPD). The silver catalyst of interest consisted of two distinct particle types, one of which contained a significant concentration of sub-surface hydroxy species (in addition to surface adsorbed atomic oxygen). Heating the sample to 663 K resulted in the production of 'pin-holes' in the silver structure as a consequence of near-surface explosions caused by sub-surface hydroxy recombination. Furthermore, 'pin-holes' were predominantly found in the vicinity of surface defects, such as platelets and edge structures. Reaction between methanol and oxygen also resulted in the formation of 'pin-holes' in the silver surface, which were inherently associated with the catalytic process. A reaction mechanism is suggested that involves the interaction of methanol with sub-surface oxygen species to form sub-surface hydroxy groups. The sub-surface hydroxy species subsequently erupt through the silver surface to again produce 'pin-holes'

Environmental scanning electron microscopy of the surface of normal and vitrified leaves of Gypsophila paniculata (Babies Breath) cultured in vitro

Leaf surfaces of non-tissue-cultured, vitrified and non-vitrified plantlets of Gypsophila paniculata (Babies Breath) were examined using an environmental scanning electron microscope. Non-tissue-cultured plants had a complete epidermal surface, recessed stomata and wax present on the leaf surface. The surface of tissue-cultured plantlets appeared similar to non-tissue-cultured plants excepting stomata were slightly protruding and less wax appeared to be present. In both non-tissue-cultured and tissue-cultured plants stomata were found both opened and closed and were observed closing. In contrast vitrified plantlets had abnormal, malformed stomata which appeared non-functional. The ventral surfaces of leaves seemed more normal than the dorsal, this may be due to the former receiving more light. Additionally, discontinuities were found in the epidermis. Often epidermal holes were found in association with stomatal apertures. It is suggested that the main cause of desiccation of vitrified G. paniculata plantlets ex vitro is due to loss of water from the discontinuity in epidermis and not because of non-functional stomata. Liquid water could be seen through the epidermal holes indicating that at least some of the extra water in vitrified plantlets is contained in the intercellular spaces

ESEM study of osmotic swelling of bentonite from Radzionkow (Poland)

Swelling tests using an environmental scanning electron microscope (ESEM) have been carried out on bentonite of Carboniferous age from the Radzionkow coal mine, Poland. The bentonite consists mostly of smectite in which sodium is the main exchangeable cation. ESEM test results revealed that in all samples osmotic swelling of constituent smectite in response to freshwater immersion led to significant microstructural reorganisation, similar to that recently recorded for freshwater-treated, smectitic clay in reservoir sandstones. Freshwater exposure caused the bentonite to become significantly less compact and more (micro)porous due to osmotic swelling of constituent smectite