On the origins of oxygenic photosynthesis and aerobic respiration in Cyanobacteria

The origin of oxygenic photosynthesis in Cyanobacteria led to the rise of oxygen on Earth ~2.3 billion years ago, profoundly altering the course of evolution by facilitating the development of aerobic respiration and complex multicellular life. Here we report the genomes of 41 uncultured organisms related to the photosynthetic Cyanobacteria (class Oxyphotobacteria), including members of the class Melainabacteria and a new class of Cyanobacteria (class Sericytochromatia) that is basal to the Melainabacteria and Oxyphotobacteria. All members of the Melainabacteria and Sericytochromatia lack photosynthetic machinery, indicating that phototrophy was not an ancestral feature of the Cyanobacteria and that Oxyphotobacteria acquired the genes for photosynthesis relatively late in cyanobacterial evolution. We show that all three classes independently acquired aerobic respiratory complexes, supporting the hypothesis that aerobic respiration evolved after oxygenic photosynthesis

Surgical management and longterm follow-up of non-parasitic hepatic cysts

BACKGROUND: Despite the increasing use of laparoscopic techniques, the optimal surgical approach for cystic liver disease has not been well defined. This study aims to determine the optimum operative approach for these patients. METHODS: Data were identified from the Lothian Surgical Audit, case note review and general practitioner contact. Patients were contacted and asked to complete the SF-36 questionnaire on quality of life. RESULTS: A total of 102 patients (67 with simple cysts, 31 with polycystic liver disease [PCLD], four with cystic tumours) underwent 62 laparoscopic deroofings, 15 open deroofings, 36 resections and one liver transplant between June 1985 and April 2006. The median follow-up was 77 months (range 3–250 months). Morbidity and recurrent symptom rates after laparoscopic surgery were greater in PCLD patients compared with simple cyst patients, at 31% (four patients) vs. 15% (seven patients) and 85% (11 patients) vs. 29% (24 patients), respectively. Four patients with simple cysts and eight with PCLD required further surgery. All patients with simple cysts had comparable quality of life after surgery. Patients with recurrent symptoms after surgery for PCLD had a significantly better quality of life following laparoscopic deroofing than after resection. CONCLUSIONS: Most simple cysts can be managed laparoscopically, but there is a definite role for open resection in some patients. Open deroofing is the preferred approach for a dominant cyst pattern in PCLD, whereas resection is necessary for diffuse cystic disease

Reductions of Hidden Information Sources

In all but special circumstances, measurements of time-dependent processes reflect internal structures and correlations only indirectly. Building predictive models of such hidden information sources requires discovering, in some way, the internal states and mechanisms. Unfortunately, there are often many possible models that are observationally equivalent. Here we show that the situation is not as arbitrary as one would think. We show that generators of hidden stochastic processes can be reduced to a minimal form and compare this reduced representation to that provided by computational mechanics--the epsilon-machine. On the way to developing deeper, measure-theoretic foundations for the latter, we introduce a new two-step reduction process. The first step (internal-event reduction) produces the smallest observationally equivalent sigma-algebra and the second (internal-state reduction) removes sigma-algebra components that are redundant for optimal prediction. For several classes of stochastic dynamical systems these reductions produce representations that are equivalent to epsilon-machines.Comment: 12 pages, 4 figures; 30 citations; Updates at http://www.santafe.edu/~cm

Theology, News and Notes - Vol. 43, No. 01

Theology News & Notes was a theological journal published by Fuller Theological Seminary from 1954 through 2014.https://digitalcommons.fuller.edu/tnn/1124/thumbnail.jp

Elevated reactive oxygen species and antioxidant enzyme activities in animal and cellular models of Parkinson's disease

AbstractThe dopaminergic neurotoxin N-methyl,4-phenyl-1,2,3,6 tetrahydropyridine (MPTP) causes a syndrome in primates and humans which mimics Parkinson's disease (PD) in clinical, pathological, and biochemical findings, including diminished activity of complex I in the mitochondrial electron transport chain. Reduced complex I activity is found in sporadic PD and can be transferred through mitochondrial DNA, suggesting a mitochondrial genetic etiology. We now show that MPTP treatment of mice and N-methylpyridinium (MPP+) exposure of human SH-SY5Y neuroblastoma cells increases oxygen free radical production and antioxidant enzyme activities. Cybrid cells created by transfer of PD mitochondria exhibit similar characteristics; however, PD cybrids' antioxidant enzyme activities are not further increased by MPP+ exposure, as are the activities in control cybrids. PD mitochondrial cybrids are subject to metabolic and oxidative stresses similar to MPTP parkinsonism and provide a model to determine mechanisms of oxidative damage and cell death in PD

Nutritional Skewing of Conceptus Sex in Sheep: Effects of a Maternal Diet Enriched in Rumen-Protected Polyunsaturated Fatty acids (PUFA)

doi:10.1186/1477-7827-6-21Evolutionary theory suggests that in polygynous mammalian species females in better body condition should produce more sons than daughters. Few controlled studies have however tested this hypothesis and controversy exists as to whether body condition score or maternal diet is in fact the determining factor of offspring sex. Here, we examined whether maternal diet, specifically increased n-6 polyunsaturated fatty acid(PUFA) intake, of ewes with a constant body condition score around the time of conception influenced sex ratio.The research was supported by USDA/CSREES/NRI Grant 2001-35203- 10693 (to RMR) and a Life Sciences Molecular Biology Fellowship, University of Missouri (partial salary support for MPG)