Storage of Wheat FoliagePrior to Enzyme-Linked Immunosorbent Assay for Detection of Wheat Soil-Borne Mosaic Virus

Plant samples, collected at various times during a growing season, are frequently stored prior to evaluating resistance to wheat soil-borne mosaic virus (WSBMV) by enzyme-linked immunosorbent assay (ELISA). Leaves of winter wheat cvs Sage and Vona, showing symptoms of WSBMV infection, were cut in half along the midrib. Each half was either: 1) refrigerated at 4 °C, 2) frozen at ?20 °C, 3) frozen at –70 °C, or 4) desiccated with CaCl₂. Relative virus antigen titres were evaluated for individual leaf halves by ELISA. ELISA absorbance means from desiccated leaf halves were consistently higher than absorbance means from corresponding leaf halves that had been frozen. This distinction suggests that virus antigen decreases during freezing but is retained during chemical desiccation. All 4 methods of storage were found to be suitable for short-term storage prior to qualitative evaluations by ELISA, but chemical desiccation was the superior method for long-term storage and for storage of foliar samples prior to quantitative evaluations by ELISA.     

Cyanamide mediated syntheses under plausible primitive earth conditions

Summary A mixture of ammonium palmitate,¹⁴C-sn-glycero-1(3)-phosphate, cyanimide and imidazole when heated for several hours formed significant quantities of phospholipids. These reaction products were shown by chromatographic, chemical and enzymatic procedures to be monopalmitoylglycerophosphate (MPGP), dipalmitoylglycerophosphate (DPGP) and monopalmitoyl cyclic glycerophosphate (cMPGP). A portion of the MPGP and DPGP possessed the same steric configuration as naturally occurring lysophosphatidic acid and phosphatidic acid. The yield of total phospholipid was maximal at temperatures between 60° and 90° after 8 h. When ratios of reactants were varied, up to 45% of radioactive glycerophosphate was converted into phospholipids. The average proportions of individual phosphatidic acids were: 60% MPGP, 27% DPGP and 13% cMPGP. Evidence was obtained for a synergistic relationship between cyanamide and imidazole in promoting the formation of phosphatidic acids. These results suggest that phosphatidic acids, which are essential precursors for the biochemical synthesis of more complex membrane phospholipids, could have been produced on the primitive Earth.The following abbreviations are employed: for phospholipid standards with designated steric configuration LPA lysophosphatidic acid (1-acyl-sn-glycero-3-phosphate) - PA phosphatidic acid (1, 2-di-acyl-sn-glycero-3-phosphate) - MPGP monopalmitoylglycerophosphate - cMPGP monopalmitoyl cyclic glycerophosphate (1(3)-acyl-sn-glycero-2,3 (1,2)-cyclic phosphate) - DPGP dipalmitoylglycerophosphate - GP glycerophosphate - cGP cyclic glycerophosphate (sn-glycero-2,3 (1,2)-cyclic phosphate) - TLC thin layer chromatography To whom reprint requests should be addressed.     

Strategies for farmers and policy makers to control nitro-gen losses whilst maintaining crop production

The nitrogen (N) cycle is essentially 'leaky'. The losses of small amounts of nitrate to waters and of ammonia and nitrous oxide to the atmosphere are a part of the global biogeo-chemical N cycle. However, intensive agricultural production, industry and vehicle use have more than doubled the amount of 'reactive' N in the environment, resulting in eutrophication, ecosystem change and health concerns. Research has identified agricultural practices that cause large losses of N and, in some cases, developed solutions. This paper discusses the problems of maintaining productivity while reducing N losses, compares conventional with low input (integrated) and organic farming systems, and discusses wider options. It also looks at the need to integrate studies on N with other environmental impacts, set in the context of the whole farm system, to provide truly sustainable agricultural systems.     

EMG area scaling and velocity modulations in a spatiotemporally constrained movement

Research examining the electromyographic (EMG) burst structure of rapid discrete limb movements has led to discordant findings concerning agonist burst duration. Some research has shown that duration varies as a function of movement speed while other research has shown burst constancy. Unfortunately, much of this research may be confounded by not carefully controlling movement termination accuracy and movement time (MT). Due to these potential problems, the present study was conducted to determine the effects of strict spatiotemporal constraints on EMG characteristics of a rapid elbow flexion-extension response under two movement extent conditions across five different MTs. Results revealed that a decreased MT was accompanied by a decreased agonist (biceps) burst duration and increased agonist burst amplitude. The burst duration and amplitude both increased as the movement extent increased with MT held constant. None of three current theoretical perspectives of rapid movement control (the impulse-timing model, the speed-control system hypothesis, or the speed-sensitive strategy) could fully account for these results. Instead, a control strategy was exhibited in which moving faster was accomplished by relative scaling of burst area via concomitant expansion of burst amplitude and compression of burst duration.     

Population-Based Analysis of Invasive Nontypeable Pneumococci Reveals That Most Have Defective Capsule Synthesis Genes

Since nasopharyngeal carriage of pneumococcus precedes invasive pneumococcal disease, characteristics of carriage isolates could be incorrectly assumed to reflect those of invasive isolates. While most pneumococci express a capsular polysaccharide, nontypeable pneumococci are sometimes isolated. Carriage nontypeables tend to encode novel surface proteins in place of a capsular polysaccharide synthetic locus, the cps locus. In contrast, capsular polysaccharide is believed to be indispensable for invasive pneumococcal disease, and nontypeables from population-based invasive pneumococcal disease surveillance have not been extensively characterized. We received 14,328 invasive pneumococcal isolates through the Active Bacterial Core surveillance program during 2006–2009. Isolates that were nontypeable by Quellung serotyping were characterized by PCR serotyping, sequence analyses of the cps locus, and multilocus sequence typing. Eighty-eight isolates were Quellung-nontypeable (0.61%). Of these, 79 (89.8%) contained cps loci. Twenty-two nontypeables exhibited serotype 8 cps loci with defects, primarily within wchA. Six of the remaining nine isolates contained previously-described aliB homologs in place of cps loci. Multilocus sequence typing revealed that most nontypeables that lacked capsular biosynthetic genes were related to established non-encapsulated lineages. Thus, invasive pneumococcal disease caused by nontypeable pneumococcus remains rare in the United States, and while carriage nontypeables lacking cps loci are frequently isolated, such nontypeable are extremely rare in invasive pneumococcal disease. Most invasive nontypeable pneumococci possess defective cps locus genes, with an over-representation of defective serotype 8 cps variants.     

Linear chromosomal physical and genetic map of Borrelia burgdorferi, the Lyme disease agent

A physical map of the 952kbp chromosome of Borrelia burgdorferi Sh-2-82 has been constructed. Eighty-three intervals on the chromosome, defined by the cleavage sites of 15 restriction enzymes, are delineated. The intervals vary in size from 96kbp to a few hundred bp, with an average size of 11.5 kbp. A striking feature of the map is its linearity; no other bacterial groups are known to have linear chromosomes. The two ends of the chromosome do not hybridize with one another, indicating that there are no large common terminal regions. The chromosome of this strain was found to be stable in culture; passage 6, 165 and 320 cultures have identical chromosomal restriction maps. We have positioned all previously known Borrelia burgdorferi chromosomal genes and several newly identified ones on this map. These include the gyrA/gyrB/dnaA/dnaN gene cluster, the rRNA gene cluster, fla, flgE, groEL (hsp60), recA, the rho/hip cluster, the dnaK (hsp70)/dnaJ/grpE cluster, the pheT/pheS cluster, and the genes which encode the potent immunogen proteins p22A, p39 and p83. Our electrophoretic analysis detects five linear and at least two circular plasmids in B. burgdorferi Sh-2-82. We have constructed a physical map of the 53 kbp linear plasmid and located the operon that encodes the two major outer surface proteins ospA and ospB on this plasmid. Because of the absence of functional genetic tools for this organism, these maps will serve as a basis for future mapping, cloning and sequencing studies of B. burgdorferi.     

Physiological and proteomic analyses of Fe(III)‐reducing co‐cultures of Desulfotomaculum reducens MI‐1 and Geobacter sulfurreducens PCA

We established Fe(III)‐reducing co‐cultures of two species of metal‐reducing bacteria, the Gram‐positive Desulfotomaculum reducens MI‐1 and the Gram‐negative Geobacter sulfurreducens PCA. Co‐cultures were given pyruvate, a substrate that D. reducens can ferment and use as electron donor for Fe(III) reduction. G. sulfurreducens relied upon products of pyruvate oxidation by D. reducens (acetate, hydrogen) for use as electron donor in the co‐culture. Co‐cultures reduced Fe(III) to Fe(II) robustly, and Fe(II) was consistently detected earlier in co‐cultures than pure cultures. Notably, faster cell growth, and correspondingly faster pyruvate oxidation, was observed by D. reducens in co‐cultures. Global comparative proteomic analysis was performed to observe differential protein abundance during co‐culture vs. pure culture growth. Proteins previously associated with Fe(III) reduction in G. sulfurreducens, namely c‐type cytochromes and type IV pili proteins, were significantly increased in abundance in co‐cultures relative to pure cultures. D. reducens ribosomal proteins were significantly increased in co‐cultures, likely a reflection of faster growth rates observed for D. reducens cells while in co‐culture. Furthermore, we developed multiple reaction monitoring (MRM) assays to quantitate specific biomarker peptides. The assays were validated in pure and co‐cultures, and protein abundance ratios from targeted MRM and global proteomic analysis correlate significantly.     

Obesity in Adolescence Predicts Lower Educational Attainment and Income in Adulthood: The Project EAT Longitudinal Study

Objective

Prospective associations between obesity in adolescence and adult socioeconomic outcomes, and potential mediators, were examined in a contemporary cohort.

Methods

Longitudinal data collected in 1998 to 1999 (Project EAT‐I) and 2015 to 2016 (EAT‐IV) were analyzed for 1,796 participants who provided data at both time points. Adolescents (mean age = 14.8 years) self‐reported demographic and psychosocial variables (EAT‐I) and follow‐up outcomes (EAT‐IV). Body weight and height were directly measured. Bachelor's degree or more education, income ≥ US $50,000, and partnered status at follow‐up were examined by baseline obesity (>95th BMI percentile) using logistic regression. Self‐esteem, depression, and weight‐related teasing were examined as mediators using multivariate probit regressions. All analyses were adjusted for race, baseline age, and parent socioeconomic status.

Results

Girls with obesity were significantly less likely to have achieved a bachelor’s degree (OR 0.32, 95% CI [0.18, 0.58]; P < 0.001), earn ≥ $50,000 annually (OR 0.57, 95% CI [0.33, 0.99]; P < 0.04), or be partnered (OR 0.45, 95% CI [0.27, 0.75]; P < 0.002) in adulthood. No associations were observed among boys. Among girls, depression mediated 8.5% and 23.6% of the association between adolescent obesity and adult education and income, respectively.

Conclusions

Adolescent girls with obesity have lower educational attainment and income and are less likely to be partnered in later adulthood. Depression may partly mediate the associations.

     

Bioenergetic Constraints on Microbial Hydrogen Utilization in Precambrian Deep Crustal Fracture Fluids

Precambrian Shield rocks host the oldest fracture fluids on Earth, with residence times up to a billion years or more. Water–rock reactions in these fracture systems over geological time have produced highly saline fluids, which can contain millimolar concentrations of H₂. Mixing of these ancient Precambrian fluids with meteoric or palaeo-meteoric water can occur through tectonic fracturing, providing microbial inocula and redox couples to fuel blooms of subsurface growth. Here, we present geochemical and microbiological data from a series of borehole fluids of varying ionic strength (0.6–6.4 M) from the Thompson Mine (Manitoba) within the Canadian Precambrian Shield. Thermodynamic calculations demonstrate sufficient energy for H₂-based catabolic reactions across the entire range of ionic strengths during mixing of high ionic strength fracture fluids with meteoric water, although microbial H₂ consumption and cultivable H₂-utilizing microbes were only detected in fluids of ≤1.9 M ionic strength. This pattern of microbial H₂ utilization can be explained by the higher potential bioenergetic cost of organic osmolyte synthesis at increasing ionic strengths. We propose that further research into the bioenergetics of osmolyte regulation in halophiles is warranted to better constrain the habitability zones of hydrogenotrophic ecosystems in both terrestrial subsurface, including potential future radioactive waste disposal sites, and other planetary body crustal environments, including Mars.