The cytoplasmic carbonic anhydrases βCA2 and βCA4 are required for optimal plant growth at low CO\u3csub\u3e2\u3c/sub\u3e

© 2016 American Society of Plant Biologists. All Rights Reserved. Carbonic anhydrases (CAs) are zinc metalloenzymes that interconvert CO2 and HCO3-. In plants, both α-and β-type CAs are present. We hypothesize that cytoplasmic bCAs are required to modulate inorganic carbon forms needed in leaf cells for carbonrequiring reactions such as photosynthesis and amino acid biosynthesis. In this report, we present evidence that βCA2 and βCA4 are the two most abundant cytoplasmic CAs in Arabidopsis (Arabidopsis thaliana) leaves. Previously, βCA4 was reported to be localized to the plasma membrane, but here, we show that two forms of βCA4 are expressed in a tissue-specific manner and that the two proteins encoded by βCA4 localize to two different regions of the cell. Comparing transfer DNA knockout lines with wild-type plants, there was no reduction in the growth rates of the single mutants, βca2 and βca4. However, the growth rate of the double mutant, βca2βca4, was reduced significantly when grown at 200μL L-1 CO2. The reduction in growth of the double mutant was not linked to a reduction in photosynthetic rate. The amino acid content of leaves from the double mutant showed marked reduction in aspartate when compared with the wild type and the single mutants. This suggests the cytoplasmic CAs play an important but not previously appreciated role in amino acid biosynthesis

Development of Fe@MGO nanoparticles for enhancing the adsorption of methylene blue dye

Industrial dye effluents are a significant concern and require to be treated before being discharged into the environment. Magnesium oxide (MgO) has been known as an excellent adsorbent for a variety of environmentally polluted compounds. This study synthesizes Fe@MgO nanocomposites via a facile precipitation calcination approach by using tetraethyl orthosilicate (TEOS) as a protective and coupling agent to remove the methylene blue in the wastewater. Powder X-ray diffraction analyses (XRD) were performed to characterize the physical properties of synthesized Fe@MgO nanocomposites and scanning electron microscopy (SEM) was used to observe their morphology and particle size, and the X-ray photoelectron spectroscopy (XPS) method was used to obtain the elemental composition as well as the chemical and electronic state of the atoms within a material. The adsorption performance was studied by batch experiments using a UV- vis spectrometer for methylene blue dye (MBD) removal. The results showed that as-prepared Fe@MgO nanocomposites are composed of cubic structures of Fe, Fe3O4, and MgO with granular morphology. Fe3O4 shows magnetic properties while, Mg, Fe, and O are in the electronic configuration of 1s, 2p, and 1s with 1302.2 eV, 710 eV, and 530 eV respectively. The contact time of the as-prepared Fe@MgO for methylene blue dye was 120 min. Langmuir model fitted better with the experimental data of methylene blue adsorption with higher correlation coefficients (R2>0.9911), suggesting the methylene blue adsorption onto Fe@MgO is monolayer chemisorption. Furthermore, the maximum adsorption capacity (QM) calculated by the Langmuir model was 1857.0 mg g-1 which was close to the experimental value of 1440.0 mg g-1 . It was found that the adsorption process was very fast, and the adsorption capacity of Fe@MgO was higher compared to Fe3O4/carboxymethyl-β-cyclodextrin (CM-β-CD), MgFe2O3@SiO2, and Cobalt zinc ferrite

Cross-tolerance to abiotic stresses in halophytes: Application for phytoremediation of organic pollutants

International audienceHalopytes are plants able to tolerate high salt concentrations but no clear definition was retained for them. In literature, there are more studies that showed salt-enhanced tolerance to other abiotic stresses compared to investigations that found enhanced salt tolerance by other abiotic stresses in halophytes. The phenomenon by which a plant resistance to a stress induces resistance to another is referred to as cross-tolerance. In this work, we reviewed cross-tolerance in halophytes at the physiological, biochemical, and molecular levels. A special attention was accorded to the cross-tolerance between salinity and organic pollutants that could allow halophytes a higher potential of xenobiotic phytoremediation in comparison with glycophytes

Predictors of the development of myocarditis or acute renal failure in patients with leptospirosis: An observational study

<p>Abstract</p> <p>Background</p> <p>Leptospirosis has a varied clinical presentation with complications like myocarditis and acute renal failure. There are many predictors of severity and mortality including clinical and laboratory parameters. Early detection and treatment can reduce complications. Therefore recognizing the early predictors of the complications of leptospirosis is important in patient management. This study was aimed at determining the clinical and laboratory predictors of myocarditis or acute renal failure.</p> <p>Methods</p> <p>This was a prospective descriptive study carried out in the Teaching Hospital, Kandy, from 1st July 2007 to 31st July 2008. Patients with clinical features compatible with leptospirosis case definition were confirmed using the Microscopic Agglutination Test (MAT). Clinical features and laboratory measures done on admission were recorded. Patients were observed for the development of acute renal failure or myocarditis. Chi-square statistics, Fisher's exact test and Mann-Whitney <it>U </it>test were used to compare patients with and without complications. A logistic regression model was used to select final predictor variables.</p> <p>Results</p> <p>Sixty two confirmed leptospirosis patients were included in the study. Seven patients (11.3%) developed acute renal failure and five (8.1%) developed myocarditis while three (4.8%) had both acute renal failure and myocarditis. Conjunctival suffusion - 40 (64.5%), muscle tenderness - 28 (45.1%), oliguria - 20 (32.2%), jaundice - 12 (19.3%), hepatomegaly - 10 (16.1%), arrhythmias (irregular radial pulse) - 8 (12.9%), chest pain - 6 (9.7%), bleeding - 5 (8.1%), and shortness of breath (SOB) 4 (6.4%) were the common clinical features present among the patients. Out of these, only oliguria {odds ratio (OR) = 4.14 and 95% confidence interval (CI) 1.003-17.261}, jaundice (OR = 5.13 and 95% CI 1.149-28.003), and arrhythmias (OR = 5.774 and 95% CI 1.001-34.692), were predictors of myocarditis or acute renal failure and none of the laboratory measures could predict the two complications.</p> <p>Conclusions</p> <p>This study shows that out of clinical and laboratory variables, only oliguria, jaundice and arrhythmia are strong predictors of development of acute renal failure or myocarditis in patients with leptospirosis presented to Teaching Hospital of Kandy, Sri Lanka.</p

Associations between brominated flame retardants, including polybrominated diphenyl ethers, and immune responses among women in the California Teachers Study

ObjectiveTo evaluate the associations between brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs), exposure and circulating immune markers in a subset of women from the California Teachers Study cohort.MethodsIn this cross-sectional study, serum from 813 female participants in the California Teachers Study collected in 2013-2016 were evaluated for 11 BFR congeners and 16 immune markers. Three BFR congeners [BDE153 [2,2',4,4',5,5'-Hexabromodiphenyl ether], BDE47 [2,2',4,4'-Tetrabromodiphenyl ether], PBB153 [2,2',4,4',5,5'-Hexabromobiphenyl]] had median levels that were above the level of detection and were further evaluated for associations with circulating immune markers. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by a logistic regression model where BFR congeners (in quartiles) were associated with immune markers (dichotomized as above and below the respective median), adjusted for age and total lipids. Sensitivity analyses were also conducted evaluating BFR congeners as a continuous exposure (per pg/ml).ResultsAll participants had at least one of the 11 measured BFR congeners detected in their serum. Increasing levels of BDE47 were associated with elevated levels of BAFF (B-cell activating factor; ORQuartile 4 = 1.67, 95% CI = 1.11-2.51), soluble CD27 (sCD27, cluster of differentiation 27; ORQuartile 4 = 1.69, 95% CI = 1.12-2.55) and IL6 (interleukin 6; ORQuartile 4 = 1.74, 95% CI = 1.13-2.66). Increasing levels of PBB153 were associated with elevated levels of CXCL13 (chemokine ligand 13; ORQuartile 4 = 1.55, 95% CI = 1.02-2.35) but inversely associated with sCD27 (ORQuartile 4 = 0.57, 95% CI = 0.38-0.87). Results from continuous models of BFR were largely consistent. No associations were observed between BDE153 and any of the immune markers assessed.ConclusionsTwo BFR congeners were statistically associated with altered levels of circulating immune markers involved in B cell activation pathways; replication and further evaluation of these novel associations are warranted. If confirmed, our results add to the current literature regarding possible immune mechanisms by which BFR exposures contribute to immune-related health endpoints and conditions where B cell activation is prominent, including autoimmune conditions

Idiopathic pancreatitis is a consequence of an altering spectrum of bile nucleation time

<p>Abstract</p> <p>Background</p> <p>The pathogenesis of idiopathic pancreatitis (IP) remains poorly understood. Our hypothesis is that IP is a sequel of micro-crystallization of hepatic bile.</p> <p>Methods</p> <p>A prospective case control study compared 55 patients; symptomatic cholelithiasis - 30 (14 male, median age 36 years; mean BMI - 25.1 kg/m²), gallstone pancreatitis - 9 (3 male, median age 35 years; mean BMI - 24.86 kg/m²) and IP - 16 (9 male, median age 34 years; mean BMI -23.34 kg/m²) with 30 controls (15 male, median age 38 years; mean BMI = 24.5 kg/m²) undergoing laparotomy for conditions not related to the gall bladder and bile duct. Ultrafiltered bile from the common hepatic duct in patients and controls was incubated in anaerobic conditions and examined by polarized light microscopy to assess bile nucleation time (NT). In the analysis, the mean NT of patients with gallstones and gallstone pancreatitis was taken as a cumulative mean NT for those with established gallstone disease (EGD).</p> <p>Results</p> <p>Patients were similar to controls. Mean NT in all groups of patients was significantly shorter than controls (EGD cumulative mean NT, 1.73 +/- 0.2 days vs. controls, 12.74 +/- 0.4 days, P = 0.001 and IP patients mean NT, 3.1 +/- 0.24 days vs. controls, 12.74 +/- 0.4 days, P = 0.001). However, NT in those with IP was longer compared with those with EGD (mean NT in IP, 3.1 +/- 0.24 days vs. cumulative mean in EGD: 1.73 +/- 0.2 days, P = 0.002).</p> <p>Conclusion</p> <p>Nucleation time of bile in patients with IP is abnormal and is intermediate to nucleation time of lithogenic bile at one end of the spectrum of lithogenicity and non-lithogenic bile, at the other end.</p

A comparative study of salt tolerance parameters in 11 wild relatives of Arabidopsis thaliana

Salinity is an abiotic stress that limits both yield and the expansion of agricultural crops to new areas. In the last 20 years our basic understanding of the mechanisms underlying plant tolerance and adaptation to saline environments has greatly improved owing to active development of advanced tools in molecular, genomics, and bioinformatics analyses. However, the full potential of investigative power has not been fully exploited, because the use of halophytes as model systems in plant salt tolerance research is largely neglected. The recent introduction of halophytic Arabidopsis-Relative Model Species (ARMS) has begun to compare and relate several unique genetic resources to the well-developed Arabidopsis model. In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense. Among these species, highly salt-tolerant (L. densiflorum and L. virginicum) and moderately salt-tolerant (M. triloba and H. incana) species were identified. Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea. Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research

A three-way comparative genomic analysis of Mannheimia haemolytica isolates

<p>Abstract</p> <p>Background</p> <p><it>Mannhemia haemolytica </it>is a Gram-negative bacterium and the principal etiological agent associated with bovine respiratory disease complex. They transform from a benign commensal to a deadly pathogen, during stress such as viral infection and transportation to feedlots and cause acute pleuropneumonia commonly known as shipping fever. The U.S beef industry alone loses more than one billion dollars annually due to shipping fever. Despite its enormous economic importance there are no specific and accurate genetic markers, which will aid in understanding the pathogenesis and epidemiology of <it>M. haemolytica </it>at molecular level and assist in devising an effective control strategy.</p> <p>Description</p> <p>During our comparative genomic sequence analysis of three <it>Mannheimia haemolytica </it>isolates, we identified a number of genes that are unique to each strain. These genes are "high value targets" for future studies that attempt to correlate the variable gene pool with phenotype. We also identified a number of high confidence single nucleotide polymorphisms (hcSNPs) spread throughout the genome and focused on non-synonymous SNPs in known virulence genes. These SNPs will be used to design new hcSNP arrays to study variation across strains, and will potentially aid in understanding gene regulation and the mode of action of various virulence factors.</p> <p>Conclusions</p> <p>During our analysis we identified previously unknown possible type III secretion effector proteins, clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated sequences (Cas). The presence of CRISPR regions is indicative of likely co-evolution with an associated phage. If proven functional, the presence of a type III secretion system in <it>M. haemolytica </it>will help us re-evaluate our approach to study host-pathogen interactions. We also identified various adhesins containing immuno-dominant domains, which may interfere with host-innate immunity and which could potentially serve as effective vaccine candidates.</p