Mechanisms of inorganic carbon acquisition in Gracilaria gaditana nom. prov. (Rhodophyta)

The mechanisms for acquisition of dissolved inorganic carbon (DIC) in the red macroalga Gracilaria gaditana nom. prov. have been investigated. The capacity for HCO₃ ⁻ use by an extracellular carbonic anhydrase (CA; EC 4.2.1.1), and by an anion exchanger with similar properties to that of red blood cells (AE1), has been quantified. It was illustrated by comparing O₂ evolution rates with those theoretically supported by CO₂, as well as by photosynthesis-pH curves. Both external and internal CA, and a direct uptake were involved in HCO₃ ⁻ use, since photosynthesis and pH evolution were affected by acetazolamide, 6-ethoxyzolamide (inhibitors of external and total CA, respectively) and 4,4′-diisothiocyanatostilbene-2,2′-disulfonate, (DIDS; an inhibitor of HCO₃ ⁻ exchanger protein). The activity of the external CA was detected by a potentiometric method and by an alternative method based on the study of O₂ evolution after addition of CO₂ and acetazolamide. The latter method showed a residual photosynthetic rate due to direct HCO₃ ⁻ use. Inhibitors caused a reduction in the pH compensation points in pH-drift experiments. The CO₂ compensation points for photosynthesis increased when the inhibitors were applied, indicating a suppresion of the pathways involved in the carbon-concentrating mechanism. The net photosynthesis rates as a function of DIC concentration displayed a biphasic pattern that could be supported by the occurrence of the two mechanisms of HCO₃ ⁻ use. The potential contribution to HCO₃ ⁻ acquisition by the DIDS-sensitive mechanism was higher after culturing at a high pH. Our results suggest that the HCO₃ ⁻ use by Gracilaria gaditana is carried out by the two DIC uptake mechanisms. These operate simultaneously with different affinities for DIC, the indirect HCO₃ ⁻ use by an external CA activity being the main pathway. The presence of a carbon-concentrating mechanism confers eco-physiological advantages in a fluctuating ecosystem subjected daily to high pHs and low DIC concentrations. Received: 3 July 1998 / Accepted: 30 November 1998     

Vitamin E-inspired multi-scale imaging agent

The production and use of multi-modal imaging agents is on the rise. The vast majority of these imaging agents are limited to a single length scale for the agent (e.g. tissues only), which is typically at the organ or tissue scale. This work explores the synthesis of such an imaging agent and discusses the applications of our vitamin E-inspired multi-modal and multi-length scale imaging agents TB-Toc ((S,E)-5,5-difluoro-7-(2-(5-((6-hydroxy-2,5,7,8-tetramethylchroman-2-yl) methyl) thiophen-2-yl) vinyl)-9-methyl-5H-dipyrrolo-[1,2-c:2’,1’-f][1,3,2]diazaborinin-4-ium-5-uide). We investigate the toxicity of TB-Toc along with the starting materials and lipid based delivery vehicle in mouse myoblasts and fibroblasts. Further we investigate the uptake of TB-Toc delivered to cultured cells in both solvent and liposomes. TB-Toc has low toxicity, and no change in cell viability was observed up to concentrations of 10?mM. TB-Toc shows time-dependent cellular uptake that is complete in about 30?min. This work is the first step in demonstrating our vitamin E derivatives are viable multi-modal and length scale diagnostic tools.     

Complete genome sequence of Hirschia baltica type strain (IFAM 1418(T))

The family Hyphomonadaceae within the Alphaproteobacteria is largely comprised of bacteria isolated from marine environments with striking morphologies and an unusual mode of cell growth. Here, we report the complete genome sequence Hirschia baltica, which is only the second a member of the Hyphomonadaceae with a published genome sequence. H. baltica is of special interest because it has a dimorphic life cycle and is a stalked, budding bacterium. The 3,455,622 bp long chromosome and 84,492 bp plasmid with a total of 3,222 protein-coding and 44 RNA genes were sequenced as part of the DOE Joint Genome Institute Program CSP 2008.     

Complete genome sequence and updated annotation of Desulfovibrio alaskensis G20

Desulfovibrio alaskensis G20 (formerly Desulfovibrio desulfuricans G20) is a Gram-negative mesophilic sulfate-reducing bacterium (SRB), known to corrode ferrous metals and to reduce toxic radionuclides and metals such as uranium and chromium to sparingly soluble and less toxic forms. We present the 3.7-Mb genome sequence to provide insights into its physiology.     

The Clinical Characteristics and Pathological Patterns of Postinfectious Glomerulonephritis in HIV-Infected Patients

Background

Postinfectious glomerulonephritis (PIGN), a form of immune complex GN, is not well-defined in HIV-infected patients. This study characterizes PIGN in this patients’ population and determine the impact of histopathological patterns on renal outcome and mortality.

Methods

HIV-infected patients with PIGN from September 1998 to July 2013 were identified. Archived slides were reviewed by a blinded renal pathologist, classified into acute, persistent and healed PIGN. Groups were compared using Wilcoxon rank-sum and Fisher’s exact test. Survival analyses were performed to determine association of histopathological pattern with renal outcome and mortality.

Results

Seventy-two HIV-infected predominantly African American males were identified with PIGN. Median (interquartile range) age and creatinine at the time of renal biopsy was 48 years (41, 53) and 2.5 mg/dl (1.5, 4.9) respectively. Only 2 (3%) had acute PIGN, 42 (58%) had persistent PIGN and 28 (39%) had healed PIGN. Three patients (4%) had IgA-dominant PIGN. Only 46% of the patients had confirmed positive cultures with Staphylococcus the most common infectious agent. During a median follow up of 17 months, the pathological pattern had no impact on renal outcome (P = 0.95). Overall mortality was high occurring in 14 patients (19%); patients with healed PIGN had significantly increased mortality (P = 0.05).

Conclusion

In HIV-infected patients, Staphylococcus is the most common cause of PIGN. Renal outcome was not influenced by the histopathological pattern but those with healed PIGN had greater mortality which was potentially due to a confounder not accounted for in the study.     

Agrobacterium tumefaciens-mediated transformation of the aromatic shrub Lavandula latifolia

Transgenic plants of the aromatic shrub Lavandula latifolia (Lamiaceae) were produced using Agrobacterium tumefaciens-mediated gene transfer. Leaf and hypocotyl explants from 35–40-day old lavender seedlings were inoculated with the EHA105 strain carrying the nptII gene, as selectable marker, and the reporter gusA gene with an intron. Some of the factors influencing T-DNA transfer to L. latifolia explants were assessed. Optimal transformation rates (6.0 ± 1.6% in three different experiments) were obtained when leaf explants precultured for 1 day on regeneration medium were subcultured on selection medium after a 24 h co-cultivation with Agrobacterium. Evidence for stable integration was obtained by GUS assay, PCR and Southern hybridisation. More than 250 transgenic plants were obtained from 37 independent transformation events. Twenty-four transgenic plants from 7 of those events were successfully established in soil. -glucuronidase activity and kanamycin resistance assays in greenhouse-grown plants from two independent transgenic lines confirmed the stable expression of both gusA and nptII genes two years after the initial transformation. Evidence from PCR data, GUS assays and regeneration in the presence of kanamycin demonstrated a 1:15 Mendelian segregation of both transgenes among seedlings of the T1 progeny of two plants from one transgenic L. latifolia line.     

Voracity and feeding preferences of two aphidophagous coccinellids on Aphis citricola and Tetranychus urticae

Voracity and feeding preferences of adult Coccinella septempunctata L. and Harmonia axyridis Pallas (Coleoptera: Coccinellidae, tribe Coccinellini) were evaluated in the laboratory on a common prey, the spirea aphid, Aphis citricola van der Goot (Homoptera: Aphididae), and on the twospotted spider mite, Tetranychus urticae Koch (Acarina: Tetranychidae), a prey previously unrecorded for these two predators. The experiments were carried out in the laboratory on apple saplings (Malus domestica Borkhausen). Adult males and females of H. axyridis consumed significantly more mites than adults of C. septempunctata. For H. axyridis, males consumed 41.3 spider mites in 24 h and females 48.4, whereas for C. septempunctata males consumed 14.1 prey and females 15.2. The consumption of spirea aphids by the males was similar for the two species. Consumption by the females was significantly greater for H. axyridis (46.5) than for C. septempunctata (22.2). The two coccinellids showed a significant preference for A. citricola in the presence of T. urticae. This preference was more pronounced for C. septempunctata. The total number of prey consumed and the percentage of exploited biomass decreased significantly for C. septempunctata and stayed relatively constant for H. axyridis as the number of mites increased in the prey ratio. Our results suggest that T. urticae is only an alternative prey for both predators, and that H. axyridis should be more efficient than C. septempunctata in a prey assemblage with aphids and mites.     

Invading parasites: spillover of an alien nematode reduces survival in a native species

Biological Invasions - It is widely assumed that spillover of alien parasites to native host species severely impacts naïve populations, ultimately conferring a competitive advantage to...     

Diagrammatic scale for severity evaluation of the Eremanthus erythropappus–Puccinia velata pathosystem

Candeia (Eremanthus erythropappus (DC.) MacLeish), a native forest species from South America, has garnered commercial interest due to its production of essential oil that contains alpha-bisabolol. This compound is widely used in the pharmaceutical and cosmetics industry, with approximately 80% of Brazilian production being exported. Since candeia rust (Puccinia velata) has only been reported in Brazil, little is known about its epidemiology and control. There is no methodology to quantify rust severity in candeia, justifying the elaboration and validation of a diagrammatic scale containing eight levels of disease severity based on leaf area coverage (0.25%, 0.5%, 1%, 2%, 4%, 8%, 16% and 32%). In a natural sampling of disease in the field, 95% of the leaves showed severity below 16%, with the remaining 5% showing severities between 16% and 32% of leaf area. Validation of the proposed diagrammatic scale was performed by assessing the results from 10 inexperienced evaluators, performing evaluations of three leaves with different severity levels. The evaluations were performed at 7-day intervals; in the first instance, severity values were assigned without the diagrammatic scale, and for the second attempt, the scale proposed in this study was used. The accuracy and precision of the severity estimates produced by each evaluator compared to the real severity was analysed by linear regression and by Lin's statistics. The reproducibility of the estimates was evaluated by analysing the coefficient of determination of linear regressions by pairs of evaluators. The scale provided adequate levels of accuracy, precision, repeatability and reproducibility, indicating the proposed scale was a suitable method for quantifying the severity of candeia rust.