Synthetic Capacity Research Articles

Metabolic Engineering of Escherichia coli for Production of α-Santalene, a Precursor of Sandalwood Oil.

α-Santalene belongs to a class of natural compounds with many physiological functions and medical applications. Advances in metabolic engineering enable non-native hosts (e.g., Escherichia coli) to produce α-santalene, the precursor of sandalwood oil. However, imbalances in enzymatic activity often result in a metabolic burden on hosts and repress the synthetic capacity of the desired product. In this work, we manipulated ribosome binding sites (RBSs) to optimize an α-santalene synthetic operon in E. coli, and the best engineered E. coli NA-IS3D strain could produce α-santalene at a titer of 412 mg·L-1. Concerning the observation of the inverse correlation between indole synthesis and α-santalene production, this study speculated that indole-associated amino acid metabolism would be competitive to the synthesis of α-santalene rather than indole toxicity itself. The deletion of tnaA could lead to a 1.5-fold increase in α-santalene production to a titer of 599 mg·L-1 in E. coli tnaA- NA-IS3D. Our results suggested that the optimization of RBS sets of the synthetic module and attenuation of the competitive pathway are promising approaches for improving the production of terpenoids including α-santalene.

Studies on production and evaluation of biopigment and synthetic dye decolorization capacity of laccase produced by A. oryzae cultivated on agro-waste.

The present study investigated the screening of mono and co-culture fungal cultivations for laccase production using extracted lignin as the substrate obtained from cauliflower wastes by two different pretreatment methods. Amongst mono and mixed culture fungal cultivations, monoculture of Aspergillus oryzae exhibited the highest enzymatic activity of 29.7 ± 0.6 U mL-1 under submerged conditions and using alkali extracted lignin as substrate. Under the optimal conditions (pH 4.5, 30°C, 12days, 1% (w/v) lignin and 0.5mM Cu2+ concentration) the maximum laccase activity was estimated to be 41.3 ± 2.8 U mL-1 and production yield of 153.3 ± 2.4mg L-1. Maximum decolorization of pigment extracted from Aspergillus heteromorphus CBS 117.55 cultivated culture media was achieved by administration of 40 U g-1 of crude enzyme concentration. Thermal and pH stability of crude laccase was observed over wide ranges. The dye decolorization efficiency of crude A. oryzae laccase was studied and Congo Red exhibited maximum decolorization percentage (64 ± 1.3%) at 15µM, 50°C and pH 4.5. The kinetic study of different dye (Congo Red) concentrations obtained Vmax and Km values of 0.123 × 10-3M and 0.724mol L-1min-1, respectively.

Late gestation hyperthermia: epigenetic programming of daughter's mammary development and function

Exposure to stressors during early developmental windows, such as prenatally (i.e., in utero), can have life-long implications for an animal's health and productivity. The mammary gland starts developing in utero and, like other developing tissues and organs, may undergo fetal programming. Previous research has implicated factors, such as prenatal exposure to endocrine disruptors or alterations in maternal diet (e.g., maternal over or undernutrition), that can influence the developmental trajectory of the offspring mammary gland in postnatal life. However, the direct links between prenatal insults and future productive outcomes are less documented in livestock species. Research on in utero hyperthermia effects on early-life mammary development is scarce. This review will provide an overview of key developmental milestones taking place in the bovine mammary gland during the pre- and postnatal stages. We will showcase how intrauterine hyperthermia, experienced by the developing fetus during the last trimester of gestation, derails postnatal mammary gland development and impairs its synthetic capacity later in life. We will provide insights into the underlying histological, cellular, and molecular mechanisms taking place at key postnatal developmental life stages, including birth, weaning and the first lactation, that might explain permanent detriments in productivity long after the initial exposure to hyperthermia. Collectively, our studies indicate that prenatal hyperthermia jeopardizes the normal developmental trajectory of the mammary gland from fetal development to lactation. Further, in utero hyperthermia epigenetically programs the udder, and possibly other organs critical to lactation, yielding a less resilient and less productive cow for multiple lactations.

Sequential inverse dysregulation of the RNA helicases DDX3X and DDX3Y facilitates MYC-driven lymphomagenesis

DDX3X is a ubiquitously expressed RNA helicase involved in multiple stages of RNA biogenesis. DDX3X is frequently mutated in Burkitt lymphoma, but the functional basis for this is unknown. Here, we show that loss-of-function DDX3X mutations are also enriched in MYC-translocated diffuse large B cell lymphoma and reveal functional cooperation between mutant DDX3X and MYC. DDX3X promotes the translation of mRNA encoding components of the core translational machinery, thereby driving global protein synthesis. Loss-of-function DDX3X mutations moderate MYC-driven global protein synthesis, thereby buffering MYC-induced proteotoxic stress during early lymphomagenesis. Established lymphoma cells restore full protein synthetic capacity by aberrant expression of DDX3Y, a Y chromosome homolog, the expression of which is normally restricted to the testis. These findings show that DDX3X loss of function can buffer MYC-driven proteotoxic stress and highlight the capacity of male B cell lymphomas to then compensate for this loss by ectopic DDX3Y expression.

Potential for inhibition of checkpoint kinases 1/2 in pulmonary fibrosis and secondary pulmonary hypertension

BackgroundIdiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterised by exuberant tissue remodelling and associated with high unmet medical needs. Outcomes are even worse when IPF results in secondary...

Evaluation of Serum Cholinesterase Level as A diagnostic Marker in Chronic Liver Disease

Background: Liver is the main source of Butyrylcholinesterase (serum cholinesterase). It is a non-specific cholinesterase that is reduced in patients with advanced liver diseases. Measurement of serum Butyrylcholinesterase activity serves as a sensitive indicator of synthetic capacity of the liver. Objective: To evaluate serum cholinesterase levels in chronic liver disease patients. Patients and methods: In this study serum cholinesterase level was evaluated in chronic liver disease patients by a colorimetric kinetic assay method. Thirty cirrhotic subjects and thirty non-cirrhotic hepatic disease subjects were compared to 20 normal individuals. This study was done at Al-Azhar University Hospitals in the period between June 2018 and August 2020. Results: A significant decrease in serum Cholinestrease level was observed in all patients of chronic liver disease as compared to control group. Conclusion: Serum cholinesterase is a better diagnostic and prognostic marker than the conventional liver function test that are raised in other liver disease also.

Modelling Hydrocortisone Pharmacokinetics on a Subcutaneous Pulsatile Infusion Replacement Strategy in Patients with Adrenocortical Insufficiency.

In the context of glucocorticoid (GC) therapeutics, recent studies have utilised a subcutaneous hydrocortisone (HC) infusion pump programmed to deliver multiple HC pulses throughout the day, with the purpose of restoring normal circadian and ultradian GC rhythmicity. A key challenge for the advancement of novel HC replacement therapies is the calibration of infusion pumps against cortisol levels measured in blood. However, repeated blood sampling sessions are enormously labour-intensive for both examiners and examinees. These sessions also have a cost, are time consuming and are occasionally unfeasible. To address this, we developed a pharmacokinetic model approximating the values of plasma cortisol levels at any point of the day from a limited number of plasma cortisol measurements. The model was validated using the plasma cortisol profiles of 9 subjects with disrupted endogenous GC synthetic capacity. The model accurately predicted plasma cortisol levels (mean absolute percentage error of 14%) when only four plasma cortisol measurements were provided. Although our model did not predict GC dynamics when HC was administered in a way other than subcutaneously or in individuals whose endogenous capacity to produce GCs is intact, it was found to successfully be used to support clinical trials (or practice) involving subcutaneous HC delivery in patients with reduced endogenous capacity to synthesize GCs.

Analysis of Synthetic Voltage vs. Capacity Datasets for Big Data Li-ion Diagnosis and Prognosis

The development of data driven methods for Li-ion battery diagnosis and prognosis is a growing field of research for the battery community. A big limitation is usually the size of the training datasets which are typically not fully representative of the real usage of the cells. Synthetic datasets were proposed to circumvent this issue. This publication provides improved datasets for three major battery chemistries, LiFePO4, Nickel Aluminum Cobalt Oxide, and Nickel Manganese Cobalt Oxide 811. These datasets can be used for statistical or deep learning methods. This work also provides a detailed statistical analysis of the datasets. Accurate diagnosis as well as early prognosis comparable with state of the art, while providing physical interpretability, were demonstrated by using the combined information of three learnable parameters.

Visible-light-driven Cadogan reaction

Visible-light-driven photochemical Cadogan-type cyclization has been discovered. The organic D-A type photosensitizer 4CzIPN found to be an efficient mediator to transfer energy from photons to the transient intermediate that breaks the barriers of deoxygenation in Cadogan reaction and enables a mild metal-free access to carbazoles and related heterocycles. DFT calculation results indicate mildly endergonic formation of the intermediate complex of nitrobiarenes and PPh3, which corresponds with experimental findings regarding reaction temperature. The robust synthetic capacity of the photoredox Cadogan reaction systems has been demonstrated by the viable productivity of a broad range of carbazoles and related N-heterocycles with good tolerance of various functionalities.

Thyroid Gland Alterations in Old-Aged Wistar Rats: A Comprehensive Stereological, Ultrastructural, Hormonal, and Gene Expression Study.

The aim of the present study was to determine and elaborate on all changes in old-aged (OA) versus young-aged (YA) rat thyroids by using stereological, ultrastructural, hormonal, and gene expression analyses. We used 4- and 24-month-old male Wistar rats in our evaluation, presenting all changes in comparison with YA rats. Results showed that the thyroid parenchyma was characterized by higher absolute volumes of the gland, colloid, epithelium, and interstitium by 135, 135, 140, and 142% (p < 0.05) respectively, while the relative volumes of colloid and glands were unchanged. Ultrastructural analysis revealed less active glands, with smaller amounts of lysosomes, thyroglobulin (Tg) granules, and microvilli in the luminal colloid. Optical density values for thyroid peroxidase (TPO), Tg, and vascular-endothelial growth factor immunostaining remained unchanged; however, TPO and Tg exhibited visually stronger expression in small active follicles. Thyroxine (T4)-Tg, the relative intensity of fluorescence (RIF), serum T4, and the sodium-iodide symporter immunohistochemical and gene expressions decreased by 20, 40, 29, and 31% (p < 0.05), respectively, in OA thyroids. Pituitary thyroid-stimulating hormone (TSH) RIF increased by 44% (p < 0.05), but the TSH serum concentration remained unchanged. In conclusion, the obtained results indicate depression of the thyroid gland synthetic and secretory capacity with advanced age.

Measurement method for dispersion states of filler particles in particulate composite materials by macroscopic permittivity

A new model for estimating macroscopic permittivity was proposed to predict filler particles' dispersion states in a particulate composite material. In the model, the estimation targets are randomly packed composite materials. The composite materials were represented as a cluster of unit cells. A proposed layer structure model connected the unit cells. The macroscopic permittivity was estimated by calculating the synthetic capacity of the cluster. The proposed model was validated by comparisons between estimated and measured macroscopic permittivity of several particulate composite materials. It was also identified that the proposed model could estimate the permittivity more accurately than an existing theoretical equation's one due to considering the effects for the dispersion states of filler particles. Furthermore, it was indicated that the proposed model could also estimate the dispersion states of filler particles by the measured permittivity. The applicability of the method was confirmed by comparisons between estimated and experimental dispersion states of filler particles.

Effect of bariatric surgery on plasma levels of oxidised phospholipids, biomarkers of oxidised LDL and lipoprotein(a)

BackgroundObesity is associated with adverse cardiovascular outcomes and this is improved following bariatric surgery. Oxidised phospholipids (OxPL) are thought to reflect the pro-inflammatory effects of lipoprotein(a) [Lp(a)], and both are independent predictors of cardiovascular disease. ObjectiveOur study sought to determine the impact of bariatric surgery on OxPL, biomarkers of oxidised LDL (OxLDL) and Lp(a). MethodsThis is a prospective, observational study of 59 patients with severe obesity undergoing bariatric surgery. Blood samples were obtained prior to surgery and at 6 and 12 months after. Sixteen patients attending the tertiary medical weight management clinic at the same centre were also recruited for comparison. Lipid and metabolic blood parameters, OxLDL, OxPL on apolipoprotein B-100 (OxPL-apoB), IgG and IgM autoantibodies to MDA-LDL, IgG and IgM apoB-immune complexes and Lp(a) were measured. ResultsReduction in body mass index (BMI) was significant following bariatric surgery, from median 48 kg/m2 at baseline to 37 kg/m2 at 6 months and 33 kg/m2 at 12 months. OxPL-apoB levels decreased significantly at 12 months following surgery [5.0 (3.2–7.4) to 3.8 (3.0–5.5) nM, p = 0.001], while contrastingly, Lp(a) increased significantly [10.2 (3.8–31.9) to 16.9 (4.9–38.6) mg/dl, p = 0.002]. There were significant post-surgical decreases in IgG and IgM biomarkers, particularly at 12 months, while OxLDL remained unchanged. ConclusionsBariatric surgery results in a significant increase in Lp(a) but reductions in OxPL-apoB and other biomarkers of oxidised lipoproteins, suggesting increased synthetic capacity and reduced oxidative stress. These biomarkers might be clinically useful to monitor physiological effects of weight loss interventions.

2-Keto-D-gluconic acid and prodigiosin producing by a Serratia marcescens

Microbial fermentation has become the main method to produce target compound. In this study, a 2-Keto-D-gluconic acid (2-KGA) producing mutant strain was obtained by mutation with rational screening methods. Meanwhile, prodigiosin was produced when the nitrogen source in the medium was changed to peptone and its fermentation conditions were evaluated to achieve high-efficient accumulation. The mutant strain SDSPY-136 was firstly identified as Serratia marcescens by morphological observation and 16S rDNA sequencing. The 2-KGA synthetic capacity of S. marcescens SDSPY-136 was evaluated by shake fermentation with 110 g/L glucose as substrates. For fermentation, 2-KGA yield, conversation rate and purity of SDSPY-136 reached 104.60 g/L, 95.10%, 99.11% in 72 h. The red pigment was extracted from the fermentation broth using acidic methanol and identified as prodigiosin by FT-IR. The optimal conditions were as follows: glycerol 20 g/L, peptone 20 g/L, MgSO415 g/L, pH 6.0, a 2% (v/v) inoculum, 30 °C and 200 rpm of shaking culture. Eventually, prodigiosin reached a yield of 9.89 g/Lafter shake culturing for 50 h under this condition. The mutant S. marcescens SDSPY-136 was shown to be promising for 2-KGA and prodigiosin production and a suitable object for prodigiosin metabolism research of S. marcescens.

Abstract PO-19: Sequential inverse dysregulation of the RNA helicases DDX3X and DDX3Y facilitates MYC-driven lymphomagenesis

Abstract DDX3X is a ubiquitously expressed RNA helicase involved in multiple stages of RNA biogenesis. DDX3X is frequently mutated in Burkitt lymphoma, but the functional basis for this is unknown. Here, we show that loss-of-function DDX3X mutations are also commonly found in MYC-translocated diffuse large B-cell lymphoma. We reveal functional cooperation between mutant DDX3X and MYC in ex vivo cultured human germinal center B cells. By integrating results of iCLIP, ribosome profiling, and proteomics, we show WT DDX3X promotes the translation of mRNAs encoding components of the core translational machinery, thereby driving global protein synthesis. Loss-of-function DDX3X mutations act to buffer the effect of abrupt MYC expression and moderate MYC-driven global protein synthesis, thereby buffering MYC-induced proteotoxic stress during early lymphomagenesis. Established lymphoma cells subsequently restore full protein synthetic capacity by aberrant expression of DDX3Y, a Y-chromosome homologue that is normally expressed exclusively in testis. These findings show how sequential dysregulation of DDX3X and DDX3Y acts to titrate global protein synthesis to suit the stage-specific needs of developing lymphoma cells and identify DDX3Y as an attractive, male-specific therapeutic target absent from normal human B cells but required for the survival of male lymphomas. Citation Format: Chun Gong, Joanna A. Krupka, Jane Gao, Nicholas F. Grigoropoulos, Francesco Cucco, Sharon Barrans, De Los Mozos Igor, Zhou Peixun, Forde Sorca, Matthews Jamie, Burke Amos, Sze Siu Kwan, Beer Philip, Burton Cathy, Campbell Peter, Rand Vikki, Turner Suzanne, Ule Jernej, Roman Eve, Tooze Reuben, Oellerich Thomas, Du Ming, Samarajiwa Shamith, Daniel J. Hodson. Sequential inverse dysregulation of the RNA helicases DDX3X and DDX3Y facilitates MYC-driven lymphomagenesis [abstract]. In: Proceedings of the AACR Virtual Meeting: Advances in Malignant Lymphoma; 2020 Aug 17-19. Philadelphia (PA): AACR; Blood Cancer Discov 2020;1(3_Suppl):Abstract nr PO-19.

Mitochondria and the thermal limits of ectotherms.

Temperature is a critical abiotic factor shaping the distribution and abundance of species, but the mechanisms that underpin organismal thermal limits remain poorly understood. One possible mechanism underlying these limits is the failure of mitochondrial processes, as mitochondria play a crucial role in animals as the primary site of ATP production. Conventional measures of mitochondrial performance suggest that these organelles can function at temperatures much higher than those that limit whole-organism function, suggesting that they are unlikely to set organismal thermal limits. However, this conclusion is challenged by recent data connecting sequence variation in mitochondrial genes to whole-organism thermal tolerance. Here, we review the current state of knowledge of mitochondrial responses to thermal extremes and ask whether they are consistent with a role for mitochondrial function in shaping whole-organism thermal limits. The available data are fragmentary, but it is possible to draw some conclusions. There is little evidence that failure of maximal mitochondrial oxidative capacity as assessed in vitro sets thermal limits, but there is some evidence to suggest that temperature effects on ATP synthetic capacity may be important. Several studies suggest that loss of mitochondrial coupling is associated with the thermal limits for organismal growth, although this needs to be rigorously tested. Most studies have utilized isolated mitochondrial preparations to assess the effects of temperature on these organelles, and there remain many untapped opportunities to address these questions using preparations that retain more of their biological context to better connect these subcellular processes with whole-organism thermal limits.

Is hyperbilirubinemia a contraindication for neonatal circumcision? A survey of practice patterns of pediatric urologists and a review of the literature

50-80% of term newborns develop jaundice, or hyperbilirubinemia (HB), in their first week. The vast majority have benign etiologies, including physiologic jaundice of the newborn and breast milk/breastfeeding jaundice, which do not affect the synthetic capacity of the liver, thus conferring a low risk of peri-procedural bleeding. Though uncommon, HB in the setting of sepsis, biliary obstruction, or metabolic disease, may increase procedural bleeding risk. Circumcision of neonates with HB has not been well studied. We sought to characterize practice patterns among Society of Pediatric Urology (SPU) members and to explore whether HB confers increased bleeding risk for newborn circumcision. An anonymous survey of 14 multiple-choice questions was sent to members of the SPU listserv. Questions regarding circumcision and HB were presented. We performed a literature review regarding whether HB confers increased surgical bleeding risk. 100/234 (43%) SPU members completed the survey. The majority (79/100) perform neonatal circumcision and use the Gomco© clamp (68%). 24/79 (30%) factor total bilirubin (Tbili) level in their decision prior to performing circumcision. Of those who consider HB a factor, 11/24 (46%) had cutoff Tbili levels at which they await improvement prior to proceeding. The most common cutoff level was Tbili level of 10-15mg/dL (6/11, 55%). Existing data suggest a possible increased bleeding risk isolated to cases of HB in the setting of biliary obstruction or other associated relevant findings (ill infant, recent infection, congenital syndromes) or known personal/family history (fulminant liver disease, familial bleeding diatheses). While literature from Jewish Mohels and Talmudic discussion suggest that elevated Tbili may be a contraindication to circumcision, no scientific studies exist directly assessing the impact of HB on bleeding risk with circumcision. A review of the scientific literature suggests that isolated HB in otherwise healthy newborns does not increase bleeding risk. 30% of pediatric urologists survey respondents consider HB a potential contraindication to neonatal circumcision. Despite varied practices in circumcising jaundiced babies, neonatal jaundice rarely confers increased bleeding risks. While deferring circumcision is appropriate in an ill infant with HB, or in those with a genetic/congenital syndrome or with family history of coagulopathic, review of the scientific literature suggests that in otherwise healthy neonates, elevated Tbili likely represents benign causes and is unlikely to increase bleeding risk.

The Effects of Plasmodium Falciparum Parasitaemia on Liver Synthetic Fidelity and Oxidative Stress Markers

Malaria has for century’s defiled eradication due to pathophysiological and environmental complexities. The study was aimed at revealing the effect of malaria parasitaemia on hepatic synthetic fidelity and oxidative stress markers individually and synergistically. A total of five hundred subjects constituted the sample size, out of which two hundred comprised the control and three hundred the test group with grades of parasitaemia. Serum aspartate aminotransferases (AST), alanine aminotransferase (ALT), iron, malonaldehyde and glutathione were analysed using WHO approved methods. The results obtained indicated a significant increase (p&lt;0.05) in AST, ALT, malonaldehyde, and glutathione levels in malaria infected subjects when compared to the control group respectively. The result further showed a significant decrease (p&lt;0.01) in serum iron concentration in malaria infected groups when compared to the control. In conclusion, malaria infection has a significant impact on the hepatic synthetic capacity and oxidative indicators. It is suggested that these observed biochemical change should be considered when malaria infected individuals are treated and managed.

THROMBOEMBOLISM-RISK-BASED ALGORITHM DECREASES ANTICOAGULATION RATES AND BLEEDING RISK AFTER LIVER TRANSPLANTATION

Introduction: There is scarce literature providing clinical guidance on deep vein thrombosis (DVT) management after liver transplantation (LT), where hemostatic disturbances are constantly changing as the synthetic capacity of the liver increases. We hypothesized that an anticoagulation algorithm based on thromboembolism risk would decrease anticoagulation rates and bleeding risk after LT. Materials and Methods: Ambispective, single center study. An algorithm for management of DVT after LT was developed based on thromboembolism risk according to DVT location.Data from patients who received a LT before implementation of the algorithm (control group: 2017) was collected retrospectively, and patients who received a LT during implementation of the algorithm (study group: 2018-2019) were followed prospectively. Primary endpoints included anticoagulation after diagnosis of DVT and bleeding (drop in hemoglobin ≥ 2 g/dL or transfusion of ≥2 units of blood). Safety outcomes included death, pulmonary embolism, return to OR and readmission within 30 days of LT. Univariate logistic regression analysis was performed to evaluate if implementation of the algorithm was associated with decreased odds of anticoagulation and bleeding, and to assess possible confounders. Results and Discussion: The study and control groups included 90 and 50 patients, respectively. There were no baseline differences on gender, age, or history of portal vein thrombosis, DVT or hypercoagulability disorders between groups.The study group had lower MELD scores. 16 (17.8%) patients from the study group and 5 (10%) controls developed DVT within 14 days (p=0.217). Of these, 2 (12.5%) study group and 4 (80%) control group patients received initial anticoagulation after DVT diagnosis (p=0.011). The study group had decreased odds of receiving initial anticoagulation after DVT (OR = 0.036, 95% CI: 0.003-0.503; p=0.014), and a tendency of decreased risk of bleeding (OR = 0.154, 95% CI: 0.017-1.369; p=0.093) compared to the historical cohort. MELD scores did not appear to have a significant association with DVT (OR = 1.023, 95% CI: 0.961-1.090; p=0.478), initial anticoagulation (OR = 1.089, 95% CI: 0.939-1.262; p=0.258), or bleeding (OR = 1.012, 95% CI: 0.882-1.162; p=0.860). No significant differences were observed on death, pulmonary embolism, return to OR and readmission within 30 days between groups.Conclusion: Implementation of a thromboembolism-risk-based algorithm for the management of DVT after LT decreases anticoagulation rates and may decrease bleeding risk. Use of this algorithm resulted in an increase of observation and US Doppler follow up. However, this increased surveillance balances favorably against the continuous laboratory monitoring and increased risk of bleeding associated with routine anticoagulation. Implementation of this algorithm does not seem to increase the rate of adverse events related to thromboembolism

Catchment-Scale Flood Modelling in Data-Sparse Regions Using Open-Access Geospatial Technology

Consistent data are seldom available for whole-catchment flood modelling in many developing regions, hence this study aimed to explore an integrated approach for flood modelling and mapping by combining available segmented hydrographic, topographic, floodplain roughness, calibration, and validation datasets using a two-dimensional Caesar-Lisflood hydrodynamic model to quantify and recreate the extent and impact of the historic 2012 flood in Nigeria. Available segments of remotely-sensed and in situ datasets (including hydrological, altimetry, digital elevation model, bathymetry, aerial photo, optical imagery, and radar imagery data) available to different degrees in the Niger-South hydrological area were systematically integrated to draw maximum benefits from all available data. Retrospective modelling, calibration, and validation were undertaken for the whole Niger- South hydrological catchment area of Nigeria, and then these data were segmented into sub-domains for re-validation to understand how data variability and uncertainties impact the accuracy of model outcomes. Furthermore, aerial photos were applied for the first time in the study area for flood model validation and for understanding how different physio-environmental properties influenced the synthetic aperture radar flood delineation capacity in the Niger Delta region of Nigeria. This study demonstrates how the complementary strengths of open, readily available geospatial datasets and tools can be leveraged to model and map flooding within acceptable levels of uncertainty for flood risk management.

A year in the salt marsh: Seasonal changes in gill protein expression in the temperate intertidal mussel Geukensia demissa

Organisms living in temperate and polar regions experience extensive seasonal changes in the physical and biotic environment, including temperature, insolation, and food availability, among other factors. Sessile intertidal organisms respond to such seasonal fluctuations largely through physiological and biochemical means, because their behavioral responses are severely limited. In this study, we used a proteomic approach to examine changes in seasonal protein expression of gill from the intertidal mussel Geukensia demissa, a keystone species of the western Atlantic salt marsh, over the course of one year. Gill tissue of mussels collected in summer had the greatest number of proteins significantly increased in abundance (37 of 592 spots detected on two-dimensional polyacrylamide gels), although autumn mussels revealed a comparable proportion of up-regulated proteins (31 spots). In contrast, the number of proteins changing in abundance in winter and spring mussels were substantially smaller (15 and 9, respectively). Identification of these proteins revealed both expected and unanticipated changes to the proteome. Maintenance of gill cilia dominates in the summer when filter-feeding is most active, as evidenced by cytoskeletal proteins such as tektin-4 and tubulin isoforms; a signal of protection from heat stress is also present in summer (e.g., heat shock cognate 70). In autumn oxidative stress protection (peroxiredoxin-5 and manganese-containing superoxide dismutase) and aerobic ATP synthetic capacity (ATP synthase subunits a and delta) appear to increase. In winter a signal of cold-induced oxidative stress is apparent (Mn-SOD and NADP-dependent isocitrate dehydrogenase), perhaps in association with heavy metal toxicity and exposure to pathogens. Gill tissue from spring shows relatively little environmental acclimatization, other than a possible increase in protein synthesis capacity.