Sulfolipid substitution ratios of Microcystis aeruginosa and planktonic communities as an indicator of phosphorus limitation in Lake Erie

Phosphorus (P) availability frequently limits primary production in lakes, influences the physiology of phytoplankton, shapes community structure, and can stimulate or constrain the formation of cyanobacterial blooms. Given the importance of P, numerous methods are available to assess P stress in phytoplankton communities. Marine phytoplankton are known to substitute sulfolipids for phospholipids in response to P limitation. We asked whether sulfolipid substitution might serve as an additional indicator of P stress in freshwater phytoplankton communities. The question was addressed using cultures of Microcystis aeruginosa, Lake Erie microcosms, and surveys of lipid profiles in Lake Erie during a Microcystis spp. bloom. Peak area response ratios of the intact polar lipids sulfoquinovosyldiacylglycerol (SQDG) to phosphatidylglycerol (PG) were used as the metric of lipid substitution. In cultures of M. aeruginosa NIES-843, the SQDG : PG ratio increased from ~ 0.9 to ~ 3.3 with decreasing P concentration. In P-limited communities, the SQDG : PG ratio increased from ~ 6 to ~ 11 after 48 h in microcosm controls, while P amendments reduced the ratio to ~ 3. In Lake Erie surveys, the SQDG : PG ratio ranged from ~ 0.4 to ~ 7.4 and was negatively correlated (Pearson r = −0.62) with total dissolved P. The SQDG : PG ratio was not correlated with concentrations of chlorophyll a, soluble reactive P, or N : P molar ratios. These results demonstrated that M. aeruginosa and Microcystis-dominated communities remodel lipid profiles in response to P scarcity, providing a potential short-term, time-integrated biomarker of nutrient history and P stress in fresh waters

Prostate Cancer Survival Estimates by the General Public Using Unrestricted Internet Searches and Online Nomograms.

BACKGROUND: Patient understanding of cancer-associated risk influences treatment preferences and is vital for making informed treatment decisions. Although patients traditionally relied on physician visits for cancer information, most adults now use the Internet as a primary source of health information. OBJECTIVE: To evaluate whether US adults can accurately estimate survival for hypothetical prostate cancer patients using unrestricted Internet searching and an online nomogram. DESIGN, SETTING, AND PARTICIPANTS: Adults were recruited at the Minnesota State Fair. Participants were shown a pathology report for a prostatectomy cancer specimen and asked to estimate the patient\u27s 15-yr survival using an unrestricted Internet search. Participants were then asked to re-estimate using a freely available, validated prostate cancer nomogram. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Participants\u27 answers were compared to a reference estimate and a ballpark estimate of ±10 percentage points of the reference value. RESULTS AND LIMITATIONS: A total of 129 participants met the inclusion criteria and generated complete responses. Only 12% (95% confidence interval [CI] 7.8-19.2%) were within the ballpark estimate when using unrestricted Internet searching for overall survival estimates. 23% (95% CI 16.8-31.3%) correctly used the nomogram and 51% (95% CI 42.6-59.6%) estimated within the ballpark when using the nomogram. CONCLUSIONS: Use of an unrestricted Internet search often yields inaccurate estimations of life expectancy, while estimations significantly improve with nomogram use. Physicians should educate and guide patients towards credible online health resources, facilitate their effective use, and engage in discussion with patients regarding the utility of this information. PATIENT SUMMARY: The general public finds it difficult to estimate prostate cancer survival using unrestricted Internet searches. Most patients would benefit from Internet guidance from their clinicians to better understand prostate cancer pathology reports

Pseudouridine synthase 1 deficient mice, a model for Mitochondrial Myopathy with Sideroblastic Anemia, exhibit muscle morphology and physiology alterations

Mitochondrial myopathy with lactic acidosis and sideroblastic anemia (MLASA) is an oxidative phosphorylation disorder, with primary clinical manifestations of myopathic exercise intolerance and a macrocytic sideroblastic anemia. One cause of MLASA is recessive mutations in PUS1, which encodes pseudouridine synthase 1 (Pus1p). Here we describe a mouse model of MLASA due to mutations in PUS1. As expected, certain modifications were missing in cytoplasmic and mitochondrial tRNAs from Pus1 â\u27/â\u27 animals. Pus1 â\u27/â\u27 mice were born at the expected Mendelian frequency and were non-dysmorphic. At 14 weeks the mutants displayed reduced exercise capacity. Examination of tibialis anterior (TA) muscle morphology and histochemistry demonstrated an increase in the cross sectional area and proportion of myosin heavy chain (MHC) IIB and low succinate dehydrogenase (SDH) expressing myofibers, without a change in the size of MHC IIA positive or high SDH myofibers. Cytochrome c oxidase activity was significantly reduced in extracts from red gastrocnemius muscle from Pus1 â\u27/â\u27 mice. Transmission electron microscopy on red gastrocnemius muscle demonstrated that Pus1 â\u27/â\u27 mice also had lower intermyofibrillar mitochondrial density and smaller mitochondria. Collectively, these results suggest that alterations in muscle metabolism related to mitochondrial content and oxidative capacity may account for the reduced exercise capacity in Pus1 â\u27/â\u27 mice

Correlation between Pre-Ovulatory Follicle Diameter and Follicular Fluid Metabolome Profiles in Lactating Beef Cows

Induced ovulation of small pre-ovulatory follicles reduced pregnancy rates, embryo survival, day seven embryo quality, and successful embryo cleavage in beef cows undergoing fixed-time artificial insemination. RNA-sequencing of oocytes and associated cumulus cells collected from pre-ovulatory follicles 23 h after gonadotropin-releasing hormone (GnRH) administration to induce the pre-ovulatory gonadotropin surge suggested reduced capacity for glucose metabolism in cumulus cells of follicles ≤11.7 mm. We hypothesized that the follicular fluid metabolome influences metabolic capacity of the cumulus-oocyte complex and contributes to reduced embryo cleavage and quality grade observed following induced ovulation of small follicles. Therefore, we performed a study to determine the correlation between pre-ovulatory follicle diameter and follicular fluid metabolome profiles in lactating beef cows (Angus, n = 130). We synchronized the development of a pre-ovulatory follicle and collected the follicular contents approximately 20 h after GnRH administration. We then performed ultra-high performance liquid chromatography—high resolution mass spectrometry (UHPLC-HRMS) metabolomic studies on 43 follicular fluid samples and identified 38 metabolites within pre-ovulatory follicles of increasing size. We detected 18 metabolites with a significant, positive correlation to follicle diameter. Individual and pathway enrichment analysis of significantly correlated metabolites suggest that altered glucose and amino acid metabolism likely contribute to reduced developmental competence of oocytes when small pre-ovulatory follicles undergo induced ovulation

Sulfolipid profiles of Microcystis aeruginosa and cyanobacterial blooms as an indicator of P availability

While phosphorus (P) scarcity can limit primary productivity in lakes, its oversupply can lead to the formation of cyanobacteria-dominated algal blooms. P availability influences bloom dynamics and can be seasonally limiting, even in eutrophic lakes. Marine phytoplankton alter their lipid profile by increasing sulfolipids when P is limiting. We asked whether Microcystis spp. respond in a similar manner. The ratio of sulfoquinovosyl diaclyglycerol (SQDG) to phosphatidylglycerol (PG) was used to examine lipid remodeling. In batch cultures of M. aeruginosa, the SQDG:PG ratio increased from ~0.9 to ~3.3 with decreasing initial P concentration. In P-limited Lake Erie mesocosms, SQDG:PG increased in controls from ~6 to ~11 after 48 hr, while P-addition decreased the ratio from ~6 to ~3. In non-P-limited mesocosms, the ratio was unchanged after 48 hr and P-addition treatments had no effect. In Lake Erie in situ measurements, SQDG:PG showed an inverse correlation with total dissolved P. There was no correlation with either soluble reactive P or N:P ratio. This study demonstrates that Microcystis remodels its lipid profile in response to P scarcity, providing a potential short-term, time-integrating marker of nutrient history for cyanobacterial populations during fresh water blooms