Molecular evolution of cyclin proteins in animals and fungi

<p>Abstract</p> <p>Background</p> <p>The passage through the cell cycle is controlled by complexes of cyclins, the regulatory units, with cyclin-dependent kinases, the catalytic units. It is also known that cyclins form several families, which differ considerably in primary structure from one eukaryotic organism to another. Despite these lines of evidence, the relationship between the evolution of cyclins and their function is an open issue. Here we present the results of our study on the molecular evolution of A-, B-, D-, E-type cyclin proteins in animals and fungi.</p> <p>Results</p> <p>We constructed phylogenetic trees for these proteins, their ancestral sequences and analyzed patterns of amino acid replacements. The analysis of infrequently fixed atypical amino acid replacements in cyclins evidenced that accelerated evolution proceeded predominantly during paralog duplication or after it in animals and fungi and that it was related to aromorphic changes in animals. It was shown also that evolutionary flexibility of cyclin function may be provided by consequential reorganization of regions on protein surface remote from CDK binding sites in animal and fungal cyclins and by functional differentiation of paralogous cyclins formed in animal evolution.</p> <p>Conclusions</p> <p>The results suggested that changes in the number and/or nature of cyclin-binding proteins may underlie the evolutionary role of the alterations in the molecular structure of cyclins and their involvement in diverse molecular-genetic events.</p

The impact of residual renal function and total body water volume on achieving adequate dialysis in CAPD

Aims: The objective is to evaluate the impact of residual renal function (RRF) and total body water (TBW) on achieving adequate dialysis. Methods: Sixty three CAPD patients performing four 2 liter exchanges daily were evaluated for RRF, total weekly Kt/V (TWKt/V), total weekly creatinine clearance (TWCC) and TBW. Results: In patients with residual renal function (N = 41), TWKt/V and TWCC were 2.2 +/- 0.8 and 77.4 +/- 24.5 L, respectively. In patients without RRF (N = 22), TWKt/V was 1.6 +/- 0.4 and TWCC 42.6 +/- 9.2 L. TBW correlated negatively with TWkt/V in the group without RRF (r = -0.75, P<0.001). Conclusion: It is not possible for larger patients without RRF treated with CAPD (2L x 4 exchanges) to achieve the acceptable targets for TWKt/V and TWCC due to TBW

Toward understanding and optimizing Au-hyperdoped Si infrared photodetectors

Au-hyperdoped Si absorbs near-infrared (NIR) light and recent efforts have successfully produced Si-based NIR photodetectors based on this property but with low detection efficiencies. Here, we investigate the differences between the optical and photocurrent properties of Auhyperdoped Si. Although defects introduced during fabrication of these materials may not exhibit significant optical absorption, we show that they can produce a measurable photocurrent under NIR illumination. Our results indicate that the optimal efficiency of impurity-hyperdoped Si materials is yet to be achieved and we discuss these opportunities in light of our results. This work thus represents a step forward in demonstrating the viability of using impurity-hyperdoped Si materials for NIR photodetection.The authors acknowledge the US Army (Contract No. FA5209-16-P-0104) and the Australian Nanotechnology Network travel grant for financial support on this project. B.C.J. and C.T.-K.L. acknowledge the Australian Research Council Center of Excellence for Quantum Computation and Communication Technology (Grant No. CE170100012)

ADEQUACY OF CAPD - A COMPARISON WITH OTHER DIALYSIS MODALITIES

93 dialysis patients were included in a prospective trial on treatment adequacy (45 CAPD; 10 nightly automatic peritoneal dialysis, NAPD; 8 intermittent peritoneal dialysis, IPD; 15 standard bicarbonate haemodialysis; 15 high-efficiency-haemodialysis). Urea and creatinine kinetics were analyzed as well as dietary protein intake. In CAPD, a weekly Kt/V of 1.77 was calculated including peritoneal and residual renal clearance (K(pr)t/V). Patients with residual renal function (58% of the study population) had an average residual renal clearance of 3.42 ml/min, presenting lower concentrations of urea nitrogen and creatinine in the plasma. As a consequence, lower percent excretion of urea and creatinine in the peritoneal fluid was observed in comparison to patients without residual renal function. In NAPD the weekly K(pr)t/V was 1.92 and urea nitrogen removal slightly higher than in CAPD patients. In IPD weekly K(pr)t/V was 1.23 and urea nitrogen removal definitely lower than with any other technique. In the haemodialysis groups, despite the higher clearance and a weekly Kt/V higher than 3, the urea nitrogen removal per week was comparable to that obtained in CAPD and NAPD. The concentration profiles in blood appear to be the critical factor in achieving the final target of the treatment, i.e. the excretion of the amount of waste products derived from protein breakdown and other metabolic pathways. Due to constant blood levels in CAPD such a low Kt/V can be adequate while in HD higher efficiency is required. In intermittent treatments in fact, the sudden decrease of the blood levels during the session leads to a minor removal of solutes even in the presence of higher clearances. As a consequence the predialysis levels in the next session will be higher and will permit a higher removal from the beginning, until a steady balance between intake and removal is obtained