Synthetic biology in the UK - An outline of plans and progress.

Synthetic biology is capable of delivering new solutions to key challenges spanning the bioeconomy, both nationally and internationally. Recognising this significant potential and the associated need to facilitate its translation and commercialisation the UK government commissioned the production of a national Synthetic Biology Roadmap in 2011, and subsequently provided crucial support to assist its implementation. Critical infrastructural investments have been made, and important strides made towards the development of an effectively connected community of practitioners and interest groups. A number of Synthetic Biology Research Centres, DNA Synthesis Foundries, a Centre for Doctoral Training, and an Innovation Knowledge Centre have been established, creating a nationally distributed and integrated network of complementary facilities and expertise. The UK Synthetic Biology Leadership Council published a UK Synthetic Biology Strategic Plan in 2016, increasing focus on the processes of translation and commercialisation. Over 50 start-ups, SMEs and larger companies are actively engaged in synthetic biology in the UK, and inward investments are starting to flow. Together these initiatives provide an important foundation for stimulating innovation, actively contributing to international research and development partnerships, and helping deliver useful benefits from synthetic biology in response to local and global needs and challenges.

Low avidity as a cause of prozone phenomena.

The incidence of prozones was studied, under various conditions, in a model indirect haemagglutination system and in a radioimmunoassay--both assays depending on the use of anti-immunoglobulin (anti-Ig). It was found that prozones were correlated with the presence of low avidity antibodies, and that these could compete with high avidity antibodies for the limited amount of anti-Ig available. It is proposed that the relatively rapid dissociation of low avidity antibodies allows them to form immune aggregates with the anti-Ig. With increasing size these aggregates would become more susceptible to being washed off. In this way low avidity antibodies could occupy the anti-Ig, and yet be relatively ineffective, either for haemagglutination or for the binding of radioactively labelled (or fluorescein-labelled) anti-Ig to the antigen.

Acute effects of oral propranolol on hemodynamic responses to upright exercise.

Noninvasive measurements of maximal oxygen intake and invasive measurement of systemic and pulmonary arterial pressures, arterial and mixed venous oxygen contents and direct Fick cardiac output are reported for 3 healthy men and 14 men with coronary heart disease. Observations were obtained at supine and sitting rest, during graded levels of upright exercise on a treadmill up to symptom-limited maximal effort and in two periods of recovery. The effects of 40 mg of propranolol orally were ascertained by repeating the measurements 1 to 1 1/2 hours later. The most consistent effect of propranolol was reduction of pressure-rate products at all phases; slowing of heart rate was significant only during exercise and recovery, and the greater slowing was accompanied by a significant increase in stroke volume. These changes were similar in patients with and without evidence of left ventricular impairment greater than 15 percent on exercise testing. Maximal oxygen intake decreased in healthy subjects and decreased slightly in patients with coronary heart disease with less than 15 percent left ventricular impairment or percent deviation of pressure-rate product from age-predicted normal values during the control study. Maximal oxygen intake increased in patients with more than 15 percent left ventricular impairment. Arterial-mixed venous oxygen difference increased after propranolol because of a reduction of mixed-venous oxygen content attributed to greater peripheral extraction of oxygen.

Regulation of anterior pituitary gonadotrophin subunit mRNA levels by gonadotrophin-releasing hormone in the ewe.

Abstract Levels of mRNA for the common a subunit and for the beta subunits of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured in the pituitary glands of ovariectomized hypothalamo-pituitary disconnected ewes. A control group (n = 7) received 250 ng pulses of gonadotrophin-releasing hormone (GnRH) each hour for one week. To examine the effects of changing GnRH pulse amplitude four sheep were given 250 ng pulses of GnRH for one week and then 25 ng pulses for one week. Plasma LH and FSH concentrations were lowered by reducing the GnRH pulse amplitude but pituitary levels of mRNA for a subunit were increased. Levels of mRNA for FSHbeta and LHbeta were similar with 25 ng and 250 ng pulses of GnRH. To examine the importance of pulsatile versus continuous GnRH inputs, a group of sheep was given a constant infusion of 250 ng/h GnRH for one week. Compared to sheep given 250 ng pulses of GnRH the mRNA levels for LHbeta and FSHbeta were lower in sheep given a constant infusion of GnRH; levels of a subunit mRNA were similar in the two groups. To examine the short-term effects of removing GnRH inputs, ovariectomized, hypothalamo-pituitary disconnected ewes that had been receiving 250 ng pulses of GnRH each hour were deprived of GnRH for 6 h (n = 4) or 30 h prior to slaughter; levels of mRNA for the three subunits were similar to control values in both of these groups. These studies show that wide variation in GnRH pulse amplitude has little effect on mRNA levels for the gonadotrophin subunits but message levels are affected by the mode of GnRH input (constant versus pulsatile). The maintenance of gonadotrophin subunit mRNA levels for at least 30 h after GnRH deprivation suggests that these mRNA species have a long half-life or that transcription continues after GnRH withdrawal.

Effects of bovine follicular fluid on pulsatile secretion of gonadotrophin-releasing hormone and gonadotrophins in ovariectomized ewes.

Abstract Ovariectomized ewes were injected with charcoal-extracted bovine follicular fluid (n = 5) or with hypophysectomized ewe serum (n = 5) after which hypophyseal portal blood samples were taken to monitor the release of gonadotrophin-releasing hormone (GnRH). Peripheral blood samples were also taken to monitor plasma luteinizing hormone and follicle-stimulating hormone (FSH) concentrations. Bovine follicular fluid treatment caused a 50% decrease in plasma FSH concentrations whereas hypophysectomized ewe serum did not significantly alter plasma FSH levels. The frequency and amplitude of luteinizing hormone and GnRH pulses was similar in both experimental groups. It is concluded that inhibin activity in bovine follicular fluid selectively suppresses the release of FSH by direct action on the pituitary gland, with no effect on GnRH secretion.

Angiotensin peptides in brain and pituitary of rat and sheep.

Several lines of evidence indicate that angiotensin peptides may be formed in the brain, where angiotensin II (Ang II) and angiotensin-(1-7) (Ang-(1-7)) may function as neurotransmitters. However, there is considerable controversy concerning the identity and levels of angiotensin peptides in the brain. We have used a novel high performance liquid chromatography-based radioimmunoassay to measure Ang-(1-7), Ang II, Ang-(1-9) and Ang I in various brain regions and in the pituitary of the rat and sheep. We also studied the effect of different methods of tissue extraction, and the effect of the converting enzyme inhibitor ramipril, on angiotensin peptide levels in the rat hypothalamus. The levels of Ang-(1-7), Ang II, Ang-(1-9) and Ang I were low (<25 fmol/g) in all brain regions examined, except for the sheep median eminence and cerebellar cortex where Ang II levels were 385±116 and 193±37 fmol/g (mean ± SEM, n = 6), respectively. Pituitary Ang II levels were 103±13 fmol/g in the rat and 63±18 fmol/g in the sheep. The levels of Ang-(1-7), Ang-(1-9) and Ang I were much lower than those of Ang II in brain and pituitary. Ang-(1-7) levels in the rat hypothalamus were low (<6 fmol/g) but methods of extraction which involved freezing and thawing of the tissue resulted in substantially higher levels of this peptide. Ang II levels in the rat hypothalamus (18±3 fmol/g) were reduced to undetectable levels (<6 fmol/g) by ramipril administration. The low levels of angiotensin peptides in the hypothalamus and brainstem indicate that if these peptides function as neurotransmitters in these regions, then they are of particularly low abundance. Moreover, our results indicate that the high levels of Ang-(1-7) reported previously for rat hypothalamus may be artefactual, due to the method of tissue extraction.

Stress-Related Changes in beta-Endorphin Processing: The Limitations of Slaughterhouse Material.

Abstract In the sheep, unlike many other species, a significant proportion (>25%) of immunoreactive beta-endorphin in the anterior pituitary is post-translationally modified to opioid-inactive, alpha-N-acetylated forms. In a study to determine the precise molecular nature of alpha-N-acetylated beta-endorphin immunoreactivity, we noted a striking difference in high-performance liquid chromatography profiles of anterior pituitary extracts between sheep killed on the farm, and age-, sex- and strain-matched slaughterhouse animals. These altered patterns of a-N-acetylated beta-endorphin processing were reproduced in farm animals by chronic (

Three-dimensional x-ray microtomography for medical and biological applications.

Three-dimensional (3D) x-ray microtomography is a technique for obtaining the 3D distribution of x-ray attenuation coefficients within small objects. To obtain microtomographic images apparatus has been developed which consists of a microfocal x-ray source, a computer-controlled stage for rotating the object, a 2D multi-wire gas proportional x-ray counter and a microcomputer to control image acquisition. Projection data were generated by rotating the object to discrete orientations around a single axis until of the order of 100 2D projection images of the object were collected. The projection images were transferred to a VAX 11/750 computer for subsequent 3D reconstruction using a convolution and back-projection algorithm in cone-beam geometry. The reconstructed data, comprising cubic voxels, may be displayed as sets of sequential transaxial, sagittal and coronal planes through the object. Alternatively, perspective displays of individual orthogonal sections may be formed with either intersecting planes or with these planes projected onto the surfaces of a box-like structure. The technique provides for the investigation of small-scale structures in biological specimens and we show some illustrative images of dead insects.

Nutritional surveillance using weight for age in the Southern Highlands Province, Papua New Guinea.

The nutritional status of Southern Highlands children aged 0-5 years is described in terms of weight for age for 1974-75 and 1978. No significant change in the proportion of children less than 80% mean weight for age was found, although an increase in children severely malnourished (< 60%) was noted. Differences between populations living at differing altitude and in differing language groups are also described.

Growth patterns of highland children and some possible implications for assessment of nutritional status.

Cross-sectional height and weight data from children under 5 years of age at three locations in the highlands of Papua New Guinea are analysed. The proportion of children under 90% height for age increases rapidly with age. The proportion of children under 80% weight for height is much lower at ages and peaks in the second year of life. Thus, the increase with age in the proportion of children below 80% weight for age is primarily due to a progressive increase in the height deficit. The implications of this growth pattern for monitoring nutritional status will not be clear until the relative health significance of a deficit in height as compared to a deficit in weight for height has been determined.

Influence of propranolol on exercise prescription of training heart rates.

Review of a longitudinal study of the effects of 40 mg of propranolol orally in 14 patients with coronary heart disease demonstrated a minor but not statistically significant change in the relationship of percentage of maximal oxygen uptake to percentage of maximal heart rate. In a cross-sectional comparison of several hundred patients who showed no other significant difference in initial findings in relation to propranolol, significant differences were present with respect to resting heart rate and responses to symptom-limited exercise, nevertheless the relationship of percentage of maximal oxygen uptake to the percentage of maximal heart rate was similar. Accordingly, we recommend maximal exercise testing in all patients prior to undertaking an exercise program so that their maximal heart rate can be determined accurately and rational training heart rates advised. The exercise test should be performed with the patients taking medications they anticipate continuing during the period of physical training, and if a change in medications is subsequently made then the exercise test should be repeated.

Congestive cardiomyopathy with segmental wall motion abnormalities and a non-uniform pattern of fibrosis.

A case of congestive cardiomyopathy in a 46-year-old smoker with single-vessel right coronary artery disease is presented. Segmental contraction abnormalities were present in the anterior wall. Pathologic analysis showed diffuse fibrosis consistent with a cardiomyopathy in areas of abnormal contraction and normal muscle in areas of normal contractility. Segmental wall motion abnormalities have been reported but none with microscopic studies of areas of both abnormal and normal contractility.

The in vitro effect of leptin on growth hormone secretion from primary cultured ovine somatotrophs.

Although existing data suggest an influence of leptin on circulating levels of growth hormone (GH), the action site and properties of leptin are still controversial. Using primary cultured ovine pituitary cells, we studied the direct effect of leptin on the secretion of GH. Pituitary cells were dissociated by collagenase and subjected to Percoll gradient centrifugation to enrich the somatotroph population to 60-80% of cells. Treatment of primary cultured ovine somatotrophs with leptin (10(-9)-10(-7) M) for 30 min did not affect basal, GH-releasing hormone (GHRH) (10(-7) M)- or GH-releasing peptide-2 (GHRP-2)(10(-7) M)-stimulated GH secretion. Following treatment of cells for 1-3 d with leptin, GHRH-stimulated GH secretion was reduced and GHRP-2-stimulated GH secretion increased. The combined effect of GHRH and GHRP-2 on GH secretion was not altered by the treatment of cells with leptin for 3 d. GHRH receptor mRNA levels in cultured somatotrophs were decreased but GHRP receptor mRNA levels were increased by 3-d leptin treatment. These results suggest that leptin has a long-term effect on somatotrophs to reduce GHRH receptor synthesis leading to a decrease in GHRH-stimulated GH secretion. Leptin appears, however, to have an opposite effect on GHRP receptor synthesis leading to an increase in GHRP-stimulated GH secretion.