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En la actualidad los recursos cupríferos de la Puna de Atacama atraen la atención de iniciativas mineras internacionales,donde millones de dólares se invierten en la extracción minera de uno de los recursos más ricos del mundo. Los esfuerzos prehispánicos para extraer estos minerales se han hecho evidentes a través del registro arqueológico regional. Sitios con hornos, escoria y molienda se han registrado desde el Período Formativo Tardío al Inka. Los sitios más tardíos han recibido mayor atención, mientras que se sabe poco de evidencias más antiguas o formativas. En este sentido las evidencias del sitio Ramaditas son significativas en cuanto presentan la primera indicación concreta de una fundición de cobre en la región atacameña durante el Formativo Tardío del norte de Chile (500 AC- 300 DC). Los resultados logrados aquí son los más tempranos de la región y proveen una base sólida para comprender la naturaleza de estos avances antes de la incorporación de la región al Estado Tiwanaku en tiempos más tardíos, como también la naturaleza de uno de los focos metalúrgicos más tempranos del Area Centro Sur Andina. ABSTRACT Today, the copper ores of Atacama attract the continued attention of international mining efforts, where millions of dollars are spent in the anual extraction of ore from one of the world’s richest sources. Pre-Hispanic efforts lo tap these ores are evident in the archacological record of the región. Sites with furnace, slag, and crushed ore are seen throughout the región, spanning from the Late Formative Period thougth the Inka Period. Of these, the later sites have received the most attention to date, although much more waits to be done.The archaeological evidence from Ramaditas is significant in that it is the first firm indication of copper smelting in the Atacama region itself during the Late Formative Period of Northern Chile (500 BC to AD 300). The results provided here are the earliest for the región so far, and they provide a firm foundation for understanding the nature of these efforts prior to the incorporation of the region within the Tiwanaku State of later times, as well as the nature of early melallurgy in the South Central Andes in general.

Abstract Background Combat-intense, lengthy, and multiple deployments in Iraq and Afghanistan have characterized the new millennium. The US military's all-volunteer force has never been better trained and technologically equipped to engage enemy combatants in multiple theaters of operations. Nonetheless, concerns over potential lasting effects of deployment on long-term health continue to mount and are yet to be elucidated. This report outlines how findings from the first 7 years of the Millennium Cohort Study have helped to address health concerns related to military service including deployments. Methods The Millennium Cohort Study was designed in the late 1990s to address veteran and public concerns for the first time using prospectively collected health and behavioral data. Results Over 150 000 active-duty, reserve, and National Guard personnel from all service branches have enrolled, and more than 70% of the first 2 enrollment panels submitted at least 1 follow-up survey. Approximately half of the Cohort has deployed in support of operations in Iraq and Afghanistan. Conclusion The Millennium Cohort Study is providing prospective data that will guide public health policymakers for years to come by exploring associations between military exposures and important health outcomes. Strategic studies aim to identify, reduce, and prevent adverse health outcomes that may be associated with military service, including those related to deployment.

Abstract Background Recently, numerous studies have revealed an increase in complementary and alternative medicine (CAM) use in US civilian populations. In contrast, few studies have examined CAM use within military populations, which have ready access to conventional medicine. Currently, the prevalence and impact of CAM use in US military populations remains unknown. Methods To investigate CAM use in US Navy and Marine Corps personnel, the authors surveyed a stratified random sample of 5,000 active duty and Reserve/National Guard members between December 2000 and July 2002. Chi-square tests and multivariable logistic regression were used to assess univariate associations and adjusted odds of CAM use in this population. Results and discussion Of 3,683 service members contacted, 1,446 (39.3%) returned a questionnaire and 1,305 gave complete demographic and survey data suitable for study. Among respondents, more than 37% reported using at least one CAM therapy during the past year. Herbal therapies were among the most commonly reported (15.9%). Most respondents (69.8%) reported their health as being very good or excellent. Modeling revealed that CAM use was most common among personnel who were women, white, and officers. Higher levels of recent physical pain and lower levels of satisfaction with conventional medical care were significantly associated with increased odds of reporting CAM use. Conclusion These data suggest that CAM use is prevalent in the US military and consistent with patterns in other US civilian populations. Because there is much to be learned about CAM use along with allopathic therapy, US military medical professionals should record CAM therapies when collecting medical history data.

Despite ample evidence of the efficacy and effectiveness of evidence-based parenting programs (EBPPs) within research-led environments, there is very little evidence of maintenance of effectiveness when programs are delivered as part of regular service provision. The present study examined the effectiveness of EBPPs provided during a period of sustained service-led implementation in comparison to research-led effectiveness evaluation. Data from 3706 parents who received EBPPs during sustained implementation by services were compared to data from 1390 parents who had participated in an earlier researcher-led effectiveness trial of a national roll-out of EBPPs in England. In both phases, parents completed measures of child behavior problems, parenting style and parental mental well-being prior to starting parenting programs (pre-test), at the end of the programs (post) and at 12-months follow up. Results from Generalized Estimating Equations controlling for potential covariates indicated significant improvements in child behavior problems during sustained implementation, similar to the effectiveness phase; significant improvements in parenting style which were larger than the effectiveness phase at 12-month follow up; and significant improvements in parental mental well- being. Our findings demonstrate effective maintenance of gains when EBPPs are provided as part of regular provision across a large sample of English parents. Successful long-term implementation should consider effectiveness of EBPPs across the population, given the large contextual changes that take place between researcher-led evaluations and service take-up. Our findings support the integration of EBPPs in public health approaches to addressing child behavior problems and parent well-being.

Photosynthetic organisms are able to sense energy imbalances brought about by the overexcitation of photosystem II (PSII) through the redox state of the photosynthetic electron transport chain, estimated as the chlorophyll fluorescence parameter 1-q L , also known as PSII excitation pressure. Plants employ a wide array of photoprotective processes that modulate photosynthesis to correct these energy imbalances. Low temperature and light are well established in their ability to modulate PSII excitation pressure. The acquisition of freezing tolerance requires growth and development a low temperature (cold acclimation) which predisposes the plant to photoinhibition. Thus, photosynthetic acclimation is essential for proper energy balancing during the cold acclimation process. Eutrema salsugineum ( Thellungiella salsuginea ) is an extremophile, a close relative of Arabidopsis thaliana , but possessing much higher constitutive levels of tolerance to abiotic stress. This comparative study aimed to characterize the photosynthetic properties of Arabidopsis (Columbia accession) and two accessions of Eutrema (Yukon and Shandong) isolated from contrasting geographical locations at cold acclimating and non-acclimating conditions. In addition, three different growth regimes were utilized that varied in temperature, photoperiod and irradiance which resulted in different levels of PSII excitation pressure. This study has shown that these accessions interact differentially to instantaneous (measuring) and long-term (acclimation) changes in PSII excitation pressure with regard to their photosynthetic behaviour. Eutrema accessions contained a higher amount of photosynthetic pigments, showed higher oxidation of P700 and possessed more resilient photoprotective mechanisms than that of Arabidopsis , perhaps through the prevention of PSI acceptor-limitation. Upon comparison of the two Eutrema accessions, Shandong demonstrated the greatest PSII operating efficiency (Φ PSII ) and P700 oxidizing capacity, while Yukon showed greater growth plasticity to irradiance. Both of these Eutrema accessions are able to photosynthetically acclimate but do so by different mechanisms. The Shandong accessions demonstrate a stable response, favouring energy partitioning to photochemistry while the Yukon accession shows a more rapid response with partitioning to other (non-photochemical) strategies., Competing Interests: The authors declare no conflict of interest.

Eutrema salsugineum (Thellungiella salsuginea) is an extremophile, a close relative of Arabidopsis, but possessing much higher constitutive levels of tolerance to abiotic stress. This study aimed to characterize the freezing tolerance of Arabidopsis (Columbia ecotype) and two ecotypes of Eutrema (Yukon and Shandong) isolated from contrasting geographical locations. Under our growth conditions, maximal freezing tolerance was observed after two- and three-weeks of cold acclimation for Arabidopsis and Eutrema, respectively. The ecotypes of Eutrema and Arabidopsis do not differ in their constitutive level of freezing tolerance or short-term cold acclimation capacity. However Eutrema remarkably outperforms Arabidopsis in long-term acclimation capacity suggesting a wider phenotypic plasticity for the trait of freezing tolerance. The combination of drought treatment and one-week of cold acclimation was more effective than long-term cold acclimation in achieving maximum levels of freezing tolerance in Eutrema, but not Arabidopsis. Furthermore, it was demonstrated growth conditions, particularly irradiance, are determinates of the level of freezing tolerance attained during cold acclimation suggesting a role for photosynthetic processes in adaptive stress responses., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

Low phytic acid (lpa) crops are low in phytic acid and high in inorganic phosphorus (Pi). In this study, two lpa pea genotypes, 1-150-81, 1-2347-144, and their progenitor CDC Bronco were grown in field trials for two years. The lpa genotypes were lower in IP₆ and higher in Pi when compared to CDC Bronco. The total P concentration was similar in lpa genotypes and CDC Bronco throughout the seed development. The action of myo-inositol phosphate synthase (MIPS) (EC 5.5.1.4) is the first and rate-limiting step in the phytic acid biosynthesis pathway. Aiming at understanding the genetic basis of the lpa mutation in the pea, a 1530 bp open reading frame of MIPS was amplified from CDC Bronco and the lpa genotypes. Sequencing results showed no difference in coding sequence in MIPS between CDC Bronco and lpa genotypes. Transcription levels of MIPS were relatively lower at 49 days after flowering (DAF) than at 14 DAF for CDC Bronco and lpa lines. This study elucidated the rate and accumulation of phosphorus compounds in lpa genotypes. The data also demonstrated that mutation in MIPS was not responsible for the lpa trait in these pea lines.

A protein gel is a three-dimensional network consisting of molecular interactions between biopolymers that entrap a significant volume of a continuous liquid phase (water). Molecular interactions in gels occur at junction zones within and between protein molecules through electrostatic forces, hydrogen bonding, hydrophobic associations (van der Waals attractions) and covalent bonding. Gels have the physicochemical properties of both solids and liquids, and are extremely important in the production and stability of a variety of foods, bioproducts and pharmaceuticals. In this study, gelation was induced in phenol extracted protein fractions from non-acclimated (NA) and cold-acclimated (CA) winter rye (Secale cereale L. cv Musketeer) leaf tissue after repeated freeze-thaw treatments. Gel formation only occurred at high pH (pH 12.0) and a minimum of 3-4 freeze-thaw cycles were required. The gel was thermally stable and only a specific combination of chemical treatments could disrupt the gel network. SDS-PAGE analysis identified ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) as the major protein component in the gel, although Rubisco itself did not appear to be a factor in gelation. Raman spectroscopy suggested changes in protein secondary structure during freeze-thaw cycles. Overall, the NA and CA gels were similar in composition and structure, with the exception that the CA gel appeared to be amyloidic in nature based on thioflavin T (ThT) fluorescence. Protein gelation, particularly in the apoplast, may confer protection against freeze-induced dehydration and potentially have a commercial application to improve frozen food quality., (Copyright © 2013 Elsevier Inc. All rights reserved.)

In the green alga Chlamydomonas reinhardtii, the cytosolic Glutathione Peroxidase 5 gene (GPX5) is known to be transcriptionally up-regulated in response to singlet oxygen ((1)O(2)). As demonstrated by previous studies, fusion of the promoter region of GPX5 to the Arylsulfatase 2 gene (ARS2) creates an effective reporter system that can be used to monitor (1)O(2)-driven GPX5 expression. This system was also used in this study to generate a stably transformed C. reinhardtii strain which expresses ARS2 in a (1)O(2)-dependent manner, resulting in the synthesis of a functional protein with detectable activity. Using the strain of C. reinhardtii harboring a (1)O(2)-sensitive reporter construct, a secondary mutagenic screen was performed. This allowed identification of mutant cell lines that were unable to up-regulate expression of the GPX5-ARS2 fusion in response to (1)O(2). In one of these lines, the mutation was subsequently localized to the first exon of the PSBP-like gene (PSBP2). The PSBP2 gene is part of a small protein family in C. reinhardtii, also present in all angiosperms studied thus far. While each member of the PSBP protein family contains a similar domain to the PSBP1 protein, which is a member of the oxygen evolving complex of photosystem II (PSII), the PSBP2 protein does not appear to be involved in PSII function, but may function as a sensor and/or signal mediating molecule of the (1)O(2) generated in the chloroplast.

To increase our knowledge of anaphase promoting complex (APC/C) function during plant development, we characterized an Arabidopsis thaliana T-DNA-insertion line where the T-DNA fell within the 5' regulatory region of the APC10 gene. The insert disrupted endogenous expression, resulting in overexpression of APC10 mRNA from the T-DNA- internal CaMV 35S promoter, and increased APC10 protein. Overexpression of APC10 produced phenotypes resembling those of known auxin and ethylene mutants, and increased expression of two tested auxin-regulated genes, small auxin up RNA (SAUR) 15 and SAUR24. Taken together, our data suggests that elevated APC10 likely mimics auxin and ethylene sensitive phenotypes, expanding our understanding of proteolytic processes in hormone regulation of plant development.

VAR2 is an integral thylakoid membrane protein and a member of the versatile FtsH class of metalloproteases in prokaryotes and eukaryotes. Recessive mutations in the VAR2 locus give rise to variegated plants (var2) that contain white sectors with abnormal plastids and green sectors with normal-appearing chloroplasts. In a continuing effort to isolate second-site suppressors of var2 variegation, we characterize in this report ems2505, a suppressor strain that has a virescent phenotype due to a missense mutation in At4g28590, the gene for a pioneer protein. We designated this gene SVR4 (for SUPPRESSOR OF VARIEGATION4) and the mutant allele in ems2505 as svr4-1. We demonstrate that SVR4 is located in chloroplasts and that svr4-1 single mutants are normal with respect to chloroplast anatomy and thylakoid membrane protein accumulation. However, they are modestly impaired in several aspects of photochemistry and have enhanced non-photochemical quenching (NPQ) capacity. A T-DNA insertion allele of SVR4, svr4-2, is seedling-lethal due to an early blockage of chloroplast development. We conclude that SVR4 is essential for chloroplast biogenesis, and hypothesize that SVR4 mediates some aspect of thylakoid structure or function that controls NPQ. We propose that in the suppressor strain, photoinhibitory pressure caused by a lack of VAR2 is ameliorated early in chloroplast development by enhanced NPQ capacity caused by reduced SVR4 activity. This would result in an increase in the number of chloroplasts that are able to surmount a threshold necessary to avoid photo-damage and thereby develop into functional chloroplasts.

The role of temperature during dormancy development is being reconsidered as more research emerges demonstrating that temperature can significantly influence growth cessation and dormancy development in woody plants. However, there are seemingly contradictory responses to warm and low temperature in the literature. This research/review paper aims to address this contradiction. The impact of temperature was examined in four poplar clones and two dogwood ecotypes with contrasting dormancy induction patterns. Under short day (SD) conditions, warm night temperature (WT) strongly accelerated timing of growth cessation leading to greater dormancy development and cold hardiness in poplar hybrids. In contrast, under long day (LD) conditions, low night temperature (LT) can completely bypass the short photoperiod requirement in northern but not southern dogwood ecotypes. These findings are in fact consistent with the literature in which both coniferous and deciduous woody plant species' growth cessation, bud set or dormancy induction are accelerated by temperature. The contradictions are addressed when photoperiod and ecotypes are taken into account in which the combination of either SD/WT (northern and southern ecotypes) or LD/LT (northern ecotypes only) are separated. Photoperiod insensitive types are driven to growth cessation by LT. Also consistent is the importance of night temperature in regulating these warm and cool temperature responses. However, the physiological basis for these temperature effects remain unclear. Changes in water content, binding and mobility are factors known to be associated with dormancy induction in woody plants. These were measured using non-destructive magnetic resonance micro-imaging (MRMI) in specific regions within lateral buds of poplar under SD/WT dormancing inducing conditions. Under SD/WT, dormancy was associated with restrictions in inter- or intracellular water movement between plant cells that reduces water mobility during dormancy development. Northern ecotypes of dogwood may be more tolerant to photoinhibition under the dormancy inducing LD/LT conditions compared to southern ecotypes. In this paper, we propose the existence of two separate, but temporally connected processes that contribute to dormancy development in some deciduous woody plant: one driven by photoperiod and influenced by moderate temperatures; the other driven by abiotic stresses, such as low temperature in combination with long photoperiods. The molecular changes corresponding to these two related but distinct responses to temperature during dormancy development in woody plants remains an investigative challenge.

The FAD2-like desaturases comprise a group of membrane-bound oxygenases involved in the modification of fatty acyl groups in plants and fungi. This group includes typical oleate desaturases which introduce a Delta12 cis double bond and more unusual enzymes such as Crep1, an acetylenase from the plant Crepis alpina, which introduces a triple bond in linoleate at the Delta12 position. In this study, the structure-function relationship between FAD2-like acetylenases and desaturases was examined through site-directed mutagenesis and heterologous expression. Eleven amino acid positions were identified that show complete evolutionary conservation within acetylenases or desaturases but have different amino acids in the other class of enzyme. Point mutants in Crep1 were constructed and expressed in yeast to test the role in fatty acid modification of the amino acids at the 11 positions. Results indicate the importance of five amino acid positions within Crep1 with regard to desaturase and acetylenase chemoselectivity, stereoselectivity, and substrate recognition. For example, relative to wild-type Crep1, the Y150F, F259L, and H266Q mutations all favored desaturation over acetylenation. The data indicate that small changes in primary sequence, particularly in the vicinity of the active site, can have profound changes on chemoselectivity and other aspects of the function of membrane-bound desaturase-like enzymes.

Many mitochondrial and chloroplast proteins are encoded in the nucleus and subsequently imported into the organelles via active protein transport systems. While usually highly specific, some proteins are dual-targeted to both organelles. In tobacco (Nicotiana tabacum L.), the cDNA encoding the mitochondrial isoform of NADP+-dependent isocitrate dehydrogenase (NADP+-ICDH) contains two translational ATG start sites, suggesting the possibility of tandem targeting signals. In this work, the putative mitochondrial and chloroplastic targeting signals from NADP+-ICDH were fused to a yellow fluorescent protein (YFP) reporter to generate a series of constructs and introduced into tobacco leaves by Agrobacterium-mediated transient transformation. The subsequent sub-cellular locations of the ICDH:YFP fusion proteins were then examined using confocal microscopy. Constructs predicted to be targeted to the chloroplast all localized to the chloroplast. However, this was not the case for all of the constructs that were predicted to be mitochondrial targeted. Although some constructs localized to mitochondria as expected, others appeared to be chloroplast localized. This was attributed to an additional 50 amino acid residues of the mature NADP+-ICDH protein that were present in those constructs, generated from either 'Xanthi' or 'Petit Havana' cultivars of tobacco. The results of this study raise interesting questions regarding the targeting and processing of organellar isoforms of NADP+-ICDH.

We have developed a new procedure based on the random glycosyl reaction of a partially benzoylated glycosyl acceptor with a glycosyl donor containing a 4,6-O-(4-methoxycarbonylbenzylidene) protecting group as a masked/caged ion-tag. Glycosylated products are ionically tagged by saponification of the methyl ester and the use of this anion-tag greatly simplifies the separation of the desired oligosaccharides from unreacted or excess glycosyl acceptors as well as from over-glycosylated oligosaccharides. In addition, the use of partially benzoylated acceptors greatly improves their solubility in dichloromethane increasing the yield of product formation and, also, of altering the distribution of positional isomers in favor of products derived by reaction of the donors at hydroxyl groups which otherwise would be considerably less reactive. Using this new approach in random glycosyl reactions, several oligosaccharide libraries were readily prepared in overall yields of 60-70% and the individual positional isomers present in the libraries were identified using the 'reductive-cleavage' method.

Unacceptably dark bran color has prevented the white-kernelled variety Argent from meeting grain color marketing standards for hard white wheats (Triticum aestivum L.). The objective of this research was to identify phenolic compounds that negatively affect bran color in white wheat using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and vanillin-HCl and NaOH staining methods. In mature bran, FT-ICR-MS detected derivatives of the flavonol quercetin in varieties Argent and RL4137 (red-kernelled wheat) but not in W98616, a white wheat variety with acceptable grain color. Derivatives of the isoflavone formononetin were more abundant in W98616 relative to RL4137 and Argent. Vanillin-HCl staining indicated that RL4137 sequestered high levels of proanthocyanidin (PA) throughout its entire seed coat, whereas white wheats sequestered PAs as discrete speckles. Argent possessed abundant speckles over its entire seed coat, whereas speckles were almost undetectable in W98616. In mature kernels, flavonoids throughout the seed coat of RL4137 reacted with NaOH, but only the speckles appeared to react in white wheats. W98616 consistently had lighter grain than Argent before and after NaOH treatment. Free and bound phenolic differences in bran samples confirmed that the darker seed coat color of Argent, relative to W98616, was likely due to higher total phenolic acid content. Although isoflavones accumulated in Argent and RL4137, it appears that the majority of the flux through the flavonoid pathway ultimately accumulates quercetin derivatives and PAs. In W98616, PAs accumulate, but it appears that flavonoid biosynthesis ultimately accumulates isoflavones. Argent, compared to W98616, generally accumulated higher levels of total phenolics (flavonols, stilbenes, and PAs) within its darker pigmented bran.

Thellungiella salsuginea, a wild crucifer that grows in subarctic Canada and is closely related to Arabidopsis thaliana, was examined for its suitability as a model plant for studies of tolerance to cold and freezing temperatures. Thellungiella completed its life cycle at 5 degrees C, demonstrating that temperature-sensitive processes such as seed germination and the production of pollen and seeds were resistant to cold temperatures. Moreover, the plant exhibited dramatically different vegetative and flowering phenotypes in response to growth at cold temperature and shifts to cold temperature. Northern analyses showed that genes induced by cold in Arabidopsis, including CBF1, the transcriptional activator for the cold-regulated (COR) genes COR15a and COR47, were also expressed in Thellungiella. Freezing tolerance, assayed by the regrowth of intact plants, increased from -13.0 to -18.5 degrees C after cold treatment. The plants lacked endogenous ice nucleation or anti-freeze activity, indicating a potential for supercooling. As a close relative to Arabidopsis, Thellungiella exhibits extreme cold tolerance and should be an important model system in the elucidation of stress tolerance mechanisms.

Common skin conditions during pregnancy generally can be separated into three categories: hormone-related, preexisting, and pregnancy-specific. Normal hormone changes during pregnancy may cause benign skin conditions including striae gravidarum (stretch marks); hyperpigmentation (e.g., melasma); and hair, nail, and vascular changes. Preexisting skin conditions (e.g., atopic dermatitis, psoriasis, fungal infections, cutaneous tumors) may change during pregnancy. Pregnancy-specific skin conditions include pruritic urticarial papules and plaques of pregnancy, prurigo of pregnancy, intrahepatic cholestasis of pregnancy, pemphigoid gestationis, impetigo herpetiformis, and pruritic folliculitis of pregnancy. Pruritic urticarial papules and plaques of pregnancy are the most common of these disorders. Most skin conditions resolve postpartum and only require symptomatic treatment. However, there are specific treatments for some conditions (e.g., melasma, intrahepatic cholestasis of pregnancy, impetigo herpetiformis, pruritic folliculitis of pregnancy). Antepartum surveillance is recommended for patients with intrahepatic cholestasis of pregnancy, impetigo herpetiformis, and pemphigoid gestationis.

Acclimation of wild type and the chlorina F2 mutant of barley to either high light or low temperature results in a 2- to 3-fold increase in non-photochemical quenching which occurred independently of either energy-dependent quenching (qE), xanthophyll cycle-mediated antenna quenching or state transitions. Results of in vivo thermoluminescence measurements used to address this conundrum indicated that excitation pressure regulates the temperature gap for S(2)Q(B)(-) and S(2)Q(A)(-) charge recombinations within photosystem II reaction centers. This is discussed in terms of photoprotection through non-radiative charge recombination.

Thellungiella, an Arabidopsis (Arabidopsis thaliana)-related halophyte, is an emerging model species for studies designed to elucidate molecular mechanisms of abiotic stress tolerance. Using a cDNA microarray containing 3,628 unique sequences derived from previously described libraries of stress-induced cDNAs of the Yukon ecotype of Thellungiella salsuginea, we obtained transcript profiles of its response to cold, salinity, simulated drought, and rewatering after simulated drought. A total of 154 transcripts were differentially regulated under the conditions studied. Only six of these genes responded to all three stresses of drought, cold, and salinity, indicating a divergence among the end responses triggered by each of these stresses. Unlike in Arabidopsis, there were relatively few transcript changes in response to high salinity in this halophyte. Furthermore, the gene products represented among drought-responsive transcripts in Thellungiella associate a down-regulation of defense-related transcripts with exposure to water deficits. This antagonistic interaction between drought and biotic stress response may demonstrate Thellungiella's ability to respond precisely to environmental stresses, thereby conserving energy and resources and maximizing its survival potential. Intriguingly, changes of transcript abundance in response to cold implicate the involvement of jasmonic acid. While transcripts associated with photosynthetic processes were repressed by cold, physiological responses in plants developed at low temperature suggest a novel mechanism for photosynthetic acclimation. Taken together, our results provide useful starting points for more in-depth analyses of Thellungiella's extreme stress tolerance.

The interaction of light and temperature in the modulation of the trans-delta3-hexadecenoic acid (trans-16:1) content of phosphatidylglycerol (PG) in winter rye (Secale cereale L.) was assessed and related to the organization of light-harvesting complex II (LHCII). Increasing the growth irradiance from 50 to 800 micromol m(-2) s(-1) at 20 degrees C resulted in a 1.8-fold increase in the trans-16:1 content in PG which favoured a greater preponderance of oligomeric LHCII, measured in vitro as the ratio of oligomer : monomer. Similar irradiance-dependent increases were observed during growth at 5 degrees C; however, 1.4-fold lower trans-16:1 contents and lower LHCII oligomer : monomer ratios were observed compared with growth at 20 degrees C and the same irradiance. These trends were also observed under natural field conditions. Thus, the accumulation of trans-16:1, as well as the organization of LHCII are modulated by both growth irradiance and growth temperature in an independent but additive manner. We also examined how changes in the supramolecular organization of LHCII affected the capacity for non-photochemical quenching (q(N)) and photoprotection via antenna quenching (q(O)). While q(O) was positively correlated with q(N), there was no correlation with either LHCII organization or xanthophyll cycle activity under the steady-state growth conditions examined.

Cultured cells of tobacco (Nicotiana tabacum L. cv Petit Havana) were used to investigate signals regulating the expression of the "model" nuclear gene encoding the alternative oxidase (AOX) (AOX1), the terminal oxidase of the mitochondrial alternative respiratory pathway. Several conditions shown to induce AOX1 mRNA accumulation also result in an increase in cellular citrate concentrations, suggesting that citrate and/or other tricarboxylic acid (TCA) cycle intermediates may be important signal metabolites. In addition, mitochondrial reactive oxygen species (ROS) production has recently been shown to be a factor mediating mitochondria-to-nucleus signaling for the expression of AOX1. We found that the exogenously supplied TCA cycle organic acids citrate, malate and 2-oxoglutarate caused rapid and dramatic increases in the steady-state level of AOX1 mRNA at low, near physiological concentrations (0.1 mM). Furthermore, an increase in AOX1 induced by the addition of organic acids occurs independently of mitochondrial ROS formation. Our results demonstrate that two separate pathways for mitochondria-to-nucleus signaling of AOX1 may exist, one involving ROS and the other organic acids.

Many metabolic reactions are coupled to NADPH in the mitochondrial matrix, including those involved in thiol group reduction. One enzyme linked to such processes is mitochondrial NADP+-dependent isocitrate dehydrogenase (mtICDH; EC 1.1.1.42), although the precise role of this enzyme is not yet known. Previous work has implicated mtICDH as part of a biochemical mechanism to reductively activate the alternative oxidase (AOX). We have partially purified mtICDH from tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) cell suspension cultures and localized this to a 46-kDa protein on SDS-PAGE, which was verified by peptide sequencing. In the inflorescence of the aroid Sauromatum guttatum Schott (voodoo lily), mtICDH appears to be developmentally regulated, presenting maximal specific activity during the thermogenic period of anthesis when the capacity for AOX respiration is also at its peak. Transgenic tobacco plants were generated that overexpress mtICDH and lines were obtained that demonstrated up to a 7-fold increase in mtICDH activity. In isolated mitochondria, this resulted in a measurable increase in the reductive activation of AOX in comparison with wild type. When examined in planta in response to citrate feeding, a strong conversion of AOX from its oxidized to its reduced form was observed in the transgenic line. These data support the hypothesis that mtICDH may be a regulatory switch involved in tricarboxylic acid cycle flux and the reductive modulation of AOX.

The physiologically active, gel-forming fraction of the alkali-extractable polysaccharides of Plantago ovata Forsk seed husk (psyllium seed) and some derived partial hydrolysis products were studied by compositional and methylation analysis and NMR spectroscopy. Resolving the conflicting claims of previous investigators, the material was found to be a neutral arabinoxylan (arabinose 22.6%, xylose 74.6%, molar basis; only traces of other sugars). With about 35% of nonreducing terminal residues, the polysaccharide is highly branched. The data are compatible with a structure consisting of a densely substituted main chain of beta-(1-->4)-linked D-xylopyranosyl residues, some carrying single xylopyranosyl side chains at position 2, others bearing, at position 3, trisaccharide branches having the sequence L-Araf-alpha-(1-->3)-D-Xylp-beta-(1-->3)-l-Araf. The presence of this sequence is supported by methylation and NMR data, and by the isolation of the disaccharide 3-O-beta-D-xylopyranosyl-L-arabinose as a product of partial acid hydrolysis of the polysaccharide.

A magneto-optical data storage system utilizing single-mode fiber is capable of providing high signal-to-noise ratio (SNR) recording if laser noise sources are properly managed. In particular, mode partition noise (MPN) associated with use of a Fabry-Perot laser diode can be a significant problem in a fiber-based system. The various mechanisms leading to MPN as well as to laser phase noise are discussed in the context of a system constructed with polarization-maintaining fiber. The primary noise mechanisms include spurious fiber-endface reflections and errors in the quarter-wave plate on the recording head. An understanding of these effects is essential for fabrication of a fiber-based recording system with suitable SNR performance.

Described herein is the synthesis of eight positional isomers of methylated and acetylated or benzoylated methyl 2-(acetylmethylamino)-2-deoxy-beta-D-glucopyranoside. The compounds were generated simultaneously from methyl 2-(acetylmethylamino)-2-deoxy-beta-D-glucopyranoside by sequential partial methylation and benzoylation and isolated in pure form by high-performance liquid chromatography (HPLC). The desired acetates were obtained by debenzoylation and acetylation of the pure isomers. Reported herein are the 1H NMR spectra of the benzoates and the electron-ionization mass spectra of the acetates and the tri-O-methyl derivative. Also reported for the acetates and the tri-O-methyl derivative are their linear temperature-programmed gas-liquid chromatography (GLC) retention indices on three different capillary columns.

The eight positional isomers of methylated and benzoylated 1,5-anhydroribitol were generated simultaneously from 1,5-anhydroribitol by sequential partial methylation and benzoylation, and the four meso isomers and two enantiomeric pairs of isomers so-formed were isolated in chemically pure form by high-performance liquid chromatography. The corresponding acetates were obtained by debenzoylation of the pure isomers and acetylation. Reported herein are the 1H NMR spectra of the benzoates and the electron-ionization mass spectra of the acetates and the tri-O-methyl derivative. Also reported for the acetates and the tri-O-methyl derivative are their linear temperature-programmed gas-liquid chromatography retention indices on three different capillary columns.

Instability of specialty choice and career after initial residency entry will affect health personnel projections. Military physicians may differ from civilian physicians in their specialty choice behaviors during their careers. A cohort of 336 graduates who chose family medicine residency training was identified from the graduating classes of 1969 through 1993 at a large private medical school. Current specialty identification was determined, and attrition from family medicine was computed. As of 1997, 275 graduates (82%) were still in family medicine careers, defined by American Academy of Family Physicians membership or current American Board of Family Practice certification. Of graduates who entered military programs, 22 of 77 (28%) had left family medicine careers; 39 of 259 (15%) of the graduates who entered civilian programs had left. This difference was statistically significant (p = 0.007). Family medicine career retention is lower for males in military programs compared with males in civilian programs or females in military programs.

The cell-surface carbohydrates of Porphyromonas gingivalis strain ATCC 53978 were isolated and partially characterized. Three separate polysaccharides were found to be present: an extracellular polysaccharide, capsular polysaccharide and lipopolysaccharide. The capsular polysaccharide, which had peculiar, gel-like viscoelastic properties, was found to be comprised of mannuronic acid, glucuronic acid, galacturonic acid, galactose, and 2-acetamido-2-deoxy-D-glucose in relative molar ratios of 0.6:0.9:0.5:0.5:1.0, respectively. The extracellular polysaccharide was found to contain mannose, rhamnose, glucose, galactose, and 2-acetamido-2-deoxy-D-glucose in relative molar ratios of 13.5:1.4:1.0:2.0:1.0, respectively. The lipopolysaccharide was found to contain an O-antigen with a regular tetrasaccharide repeat unit comprised of 4-linked alpha-L-rhamnopyranosyl, 6-linked alpha-D-glucopyranosyl, 3-linked alpha-D-galactopyranosyl, and 4-linked 2-acetamido-2-deoxy-beta-D-glucopyranosyl residues in equimolar proportions.

Described herein is the synthesis of the eight positional isomers of methylated and acetylated or benzoylated 1,5-anhydro-L-arabinitol. The compounds were generated simultaneously from 1,5-anhydro-L-arabinitol by sequential partial methylation and benzoylation and isolated in pure from by high-performance liquid chromatography. The desired acetates were obtained by debenzoylation and acetylation of the pure isomers. Reported herein are the 1H NMR spectra of the benzoates and the electron-ionization mass spectra of the acetates and the tri-O-methyl derivative. Also reported for the acetates and the tri-O-methyl derivative are their linear temperature-programmed gas-liquid chromatography retention indices on three different capillary columns.

High-power, external-cavity semiconductor lasers with narrow bandwidth and fiber-coupled output are designed and constructed. An output power of 540 mW is coupled out of a 100-mum multimode fiber with coupling efficiency of 72% when the laser is operated at 1.1 A. The emission linewidth is as narrow as 22 GHz, and the wavelength is tunable from 779.7 to 793.0 nm. Application of such lasers to remote real-time Raman sensing of materials is also demonstrated.

Exposure of winter rye leaves grown at 20 degrees C and an irradiance of either 50 or 250 micromol m(-2) s(-1) to high light stress (1600 micromol m(-2) s(-1), 4 h) at 5 degrees C resulted in photoinhibition of PSI measured in vivo as a 34% and 31% decrease in deltaA820/A820 (P700+). The same effect was registered in plants grown at 5 degrees C and 50 micromol m(-2) s(-1). This was accompanied by a parallel degradation of the PsaA/PsaB heterodimer, increase of the intersystem e- pool size as well as inhibition of PSII photochemistry measured as Fv/Fm. Surprisingly, plants acclimated to high light (800 micromol m(-2) s(-1)) or to 5 degrees C and moderate light (250 micromol m(-2) s(-1)) were fully resistant to photoinhibition of PSI and did not exhibit any measurable changes at the level of PSI heterodimer abundance and intersystem e- pool size, although PSII photochemistry was reduced to 66% and 64% respectively. Thus, we show for the first time that PSI, unlike PSII, becomes completely resistant to photoinhibition when plants are acclimated to either 20 degrees C/800 micromol m(-2) s(-1) or 5 degrees C/250 micromol m(-2) s(-1) as a response to growth at elevated excitation pressure. The role of temperature/light dependent acclimation in the induction of selective tolerance to PSI photoinactivation is discussed.

By comparing growth under five different temperature and irradiance regimes (20[deg]C and 800, 250, and 50[mu]mol m-2 s-1 and 5[deg]C and 250 and 50 [mu]mul m-2 s-1), we have examined the effects of light, temperature, and the relative reduction state of photosystem II on plant morphology, freezing tolerance (lethal temperature at which freezing injury occurs [LT50]), transcript levels of Lhcb and two cold-stimulated genes (Wcs19 and Wcs120), and photosynthetic adjustment in winter rye (Secale cereale L. cv Musketeer). We show, for the first time to our knowledge, that in addition to adjustments in photosynthetic capacity, nonphotochemical quenching capacity and tolerance to photoinhibition, the accumulation of the cold-induced transcript Wcs19, and the compact plant morphology usually associated with cold-hardening are correlated with the relative reduction state of photosystem II rather than with growth temperature or growth irradiance per se. In contrast, the acquisition of maximal LT50, as well as Lhcb and Wcs120 mRNA accumulation, appears to be dependent on both growth temperature and growth irradiance but in an independent, additive manner. The results are discussed with respect to the possible role of the modulation of chloroplastic redox poise in photosynthetic acclimation to cold-hardening temperatures and the attainment of maximal LT50.

The four O-benzoyl-tri-O-methyl positional isomers, the six di-O-benzoyl-di-O-methyl positional isomers, the four tri-O-benzoyl-O-methyl positional isomers, and the tetra-O-benzoyl derivative of methyl alpha-D-mannopyranoside were synthesized, characterized, and subjected to reductive cleavage in the presence of triethylsilane and trimethylsilyl trifluoromethanesulfonate. The reactions were monitored by 1H NMR spectroscopy in order to establish the rates of the reactions and the identities of the products so formed. The tetra-O-benzoyl derivative, all tri-O-benzoyl-O-methyl positional isomers, and the 2.4-di-O-benzoyl-3.6-di-O-methyl positional isomer were fully stable to reductive-cleavage conditions, but the other di-O-benzoyl-di-O-methyl positional isomers and all O-benzoyl-tri-O-methyl positional isomers were converted to their respective 1.5-anhydro-D-mannitol derivatives via reductive cleavage of their anomeric carbon-oxygen bonds. For the mono-O-benzoyl positional isomers, the rate of reductive cleavage decreased in the order 2-O-benzoyl > 6-O-benzoyl > 3-O-benzoyl approximately 4-O-benzoyl. Moreover, all mono-O-benzoyl positional isomers were cleaved at a much faster rate than the di-O-benzoyl positional isomers. These results suggest that both anchimeric assistance and inductive effects of the ester groups contribute to the observed reaction rate. Based upon these results it is suggested that reductive cleavage of benzoylated polysaccharides might serve as a means to cleave selectively at branched residues.

Several per-O-methylated monosaccharides and polysaccharides were used as models in an attempt to identify more convenient reagents for accomplishing reductive cleavage of glycosidic linkages. Included in the model studies were methyl alpha- and beta-D-glucopyranoside, methyl alpha- and beta-D-mannopyranoside, and methyl alpha- and beta-D-ribofuranoside. These studies led to the identification of a new promoter, butyltin trichloride, for carrying out reductive cleavage when borane-methyl sulfide complex was used as the reducing agent. These reagents were found to accomplish the reductive cleavage of per-O-methylated amylose, cellulose, and pullulan to give only the expected derivatives of 1,5-anhydro-D-glucitol. These reagents also accomplished reductive cleavage of per-O-methylated insulin to give only the expected derivatives of 2,5-anhydro-D-mannitol and 2,5-anhydro-D-glucitol. Reductive cleavage using these reagents is easy to perform, and subsequent acetylation of the products is readily accomplished in situ.

An experimental investigation of a semiconductor laser subject to moderate to strong optical feedback shows that sporadic power discontinuities occur everywhere along the boundary separating feedback regimes IV and V. These low-frequency fluctuations (LFF's) do not occur just near the solitary-laser threshold as previously thought. Furthermore, although the LFF's appear as power dropouts near threshold, they manifest as power jump-ups well above threshold. Theoretical modeling shows reasonable agreement with experiments.

The fully methylated cyclohexyl glycosides of 2-acetamido-2-deoxy-alpha- and beta-D-hexopyranoses having the gluco, manno, and galacto configurations were each subjected to reductive-cleavage conditions using one of three promoters, namely trimethylsilyl trifluoromethanesulfonate, a mixture of trimethylsilyl methanesulfonate and boron trifluoride etherate, or boron trifluoride etherate alone. As expected, the fully methylated 1,2-trans-linked acetamido sugar derivatives were rapidly converted to their respective oxazolinium ions with all three promoters. Surprisingly, however, the fully methylated 1,2-cis-linked acetamido sugar derivatives were also converted to their respective oxazolinium ions, albeit at a much slower rate. In the latter case, evidence was obtained for anomerization to the 1,2-trans-linked isomers under reductive-cleavage conditions. Since the anomerization was relatively slow at room temperature in dichloromethane, a modified procedure was developed in which the reaction was carried out at 70 degrees C in 1,2-dichloroethane. Using the modified procedure, all 1,2-cis- and 1,2-trans-linked acetamido sugar derivatives were rapidly converted into their respective oxazolinium ions and subsequent quenching of the reactions with anhydrous methanol gave the respective 1,2-trans-linked methyl glycoside derivatives in quantitative yield. The modified procedure is recommended for the total reductive cleavage of polysaccharides comprised of acetamido sugar residues.

Lipids extracted from Bacillus subtilis using a 2:1 mixture of chloroform and methanol have been found to be very mitogenic. These lipids were fractionated on a silica column and eluted with chloroform, acetone, and 60% methanol in chloroform, and the mitogenic activity was recovered in the last fraction. Further purification of the mitogenic components was achieved by HPLC on an amino-isopropyl bonded-phase column using a linear gradient of 5-20 mM ammonium acetate in a mobile phase consisting of hexane, 2-propanol, methanol, and water (5.5:8:1.5:1). Two major and several minor mitogenic peaks were observed. One major mitogenic lipid was isolated in pure form and structurally characterized by chemical degradation analysis, NMR spectroscopy, and mass spectrometry. Mild acid hydrolysis of the lipid released glycerol phosphate and a neutral glycolipid. Saponification of the lipid released a water-soluble head group and C14-C17 branched fatty acids. Total acid hydrolysis of the head group revealed the presence of glycerol and glucose in a ratio of 1:1. Mild acid hydrolysis of the head group to remove the glycerol phosphate produced a neutral partial head group. The partial head group was methylated and then analyzed by GLC-CIMS and by the reductive-cleavage method, which revealed that it was composed of nonreducing terminal glucopyranosyl, 6-linked glucopyranosyl, and 3-linked glycerol residues in equimolar proportions. Finally, the molecular weight of the permethylated head group, obtained by fast atom bombardment mass spectrometry, was 724.3340, which is consistent with the composition of two glucose residues, one glycerol residue, and one glycerol phosphate residue. On the basis of all these results, the intact mitogenic lipid was identified as 1,2-di-O-acyl-3-O-[6-(sn-glycerol-phospho)-beta-D-glucopyranosyl-(1-->6) - beta-D-glucopyranosyl]glycerol. The purified glycolipid possessed very potent mitogenic activity in a murine splenocyte proliferation assay at a concentration of 0.01-0.1 microgram/mL.

Winter wheat (Triticum aestivum L. cv Monopol), spring wheat (Triticum aestivum L. cv Katepwa), and winter rye (Secale cereale L. cv Musketeer) grown at 5[deg]C and moderate irradiance (250 [mu]mol m-2 s-1) (5/250) exhibit an increased tolerance to photoinhibition at low temperature in comparison to plants grown at 20[deg]C and 250 [mu]mol m-2 s-1 (20/250). However, 5/250 plants exhibited a higher photosystem II (PSII) excitation pressure (0.32-0.63) than 20/250 plants (0.18-0.21), measured as 1 - qP, the coefficient of photochemical quenching. Plants grown at 20[deg]C and a high irradiance (800 [mu]mol m-2 s-1) (20/800) also exhibited a high PSII excitation pressure (0.32-0.48). Similarly, plants grown at 20/800 exhibited a comparable tolerance to photoinhibition relative to plants grown at 5/250. In contrast to a recent report for Chlorella vulgaris (D.P. Maxwell, S. Falk, N.P.A. Huner [1995] Plant Physiol 107: 687-694), this tolerance to photoinhibition occurs in winter rye with minimal adjustment to polypeptides of the PSII light-harvesting complex, chlorophyll a/b ratios, or xanthophyll cycle carotenoids. However, Monopol winter wheat exhibited a 2.5-fold stimulation of sucrosephosphate synthase activity upon growth at 5/250, in comparison to Katepwa spring wheat. We demonstrate that low-temperature-induced tolerance to photoinhibition is not a low-temperature-growth effect per se but, instead, reflects increased photosynthetic capacity in response to elevated PSII excitation pressure, which may be modulated by either temperature or irradiance.

Mixtures consisting of five equivalents each of borane.methyl sulfide and boron trifluoride etherate per equivalent of acetal or five equivalents of various amine-borane complexes and 10 equivalents of boron trifluoride etherate readily accomplished reductive cleavage of the glycosidic linkages of several per-O-methylated monosaccharides and polysaccharides. In all cases, the expected products were obtained in the expected molar proportions and no artifactual products were observed. Reductive-cleavage analysis using these reagents is particularly convenient because the reagents themselves are easy to handle and because subsequent acetylation of the products is accomplished in situ.

Described herein is an efficient method for the synthesis of the sixteen positional isomers of methylated and acetylated or benzoylated 1,5-anhydro-D-mannitol. The compounds are generated simultaneously by partial methylation of 1,5-anhydro-D-mannitol and subsequent benzoylation, and the individual isomers are obtained in pure form by high-performance liquid chromatography. Debenzoylation of the latter and acetylation yielded the desired acetates. The the benzoates and the electron-ionization mass spectra of the acetates and the tetra-O-methyl derivative are reported herein as are the linear temperature-programmed gas-liquid chromatography retention indices of the acetates and the tetra-O-methyl derivative on three different capillary columns.

Described herein is the synthesis of all positional isomers of methylated and acetylated or benzoylated 1,4-anhydro-L-fucitol. The benzoates are generated simultaneously from 1,4-anhydro-L-fucitol by sequential partial methylation and benzoylation or sequential partial benzoylation and methylation. The individual isomers are obtained in pure form by high-performance liquid chromatography. Debenzoylation and acetylation provided the corresponding acetates. The 1H NMR spectra of the benzoates and the electron-ionization mass spectra of the acetates and the tri-O-methyl derivative are reported herein as are the linear temperature programmed gas-liquid chromatography retention indices of the acetates and the tri-O-methyl derivative on three different capillary columns.

Described is an efficient method for the synthesis of the sixteen positional isomers of methylated and acetylated or benzoylated 1,5-anhydro-D-glucitol. The compounds are generated simultaneously by partial methylation of 1,5-anhydro-D-glucitol and subsequent benzoylation, and the individual isomers are obtained in pure form by high-performance liquid chromatography. Debenzoylation of the latter and acetylation yielded the desired acetates. Reported are the 1H NMR spectra of the benzoates and the electron-ionization mass spectra of the acetates and the tetra-O-methyl derivative. Also reported for the acetates and the tetra-O-methyl derivative are their linear temperature programmed gas-liquid chromatography retention indices on three different capillary columns.

Described herein is the synthesis of all positional isomers of partially methylated and acetylated or benzoylated 1,4-anhydro-D-ribitol. The benzoates are generated simultaneously from 1,4-anhydro-D-ribitol by sequential partial methylation and benzoylation or sequential partial benzoylation and methylation. The individual isomers are obtained in pure form by high-performance liquid chromatography. Debenzoylation and acetylation provided the corresponding acetates. Reported herein are the 1H NMR spectra of the benzoates and the electron-ionization mass spectra of the acetates and the tri-O-methyl derivative and also for the acetates and the tri-O-methyl derivative, their linear temperature programmed gas-liquid chromatography retention indices on three different capillary columns.

Described herein is a general method for the synthesis of all positional isomers of methylated and acetylated or benzoylated 1,4-anhydro-D-xylitol. The benzoates are generated simultaneously from 1,4-anhydro-D-xylitol by sequential partial methylation and benzoylation or sequential partial benzoylation and methylation. The individual isomers are obtained in pure form by high-performance liquid chromatography. Debenzoylation and acetylation provided the corresponding acetates. The 1H NMR spectra of the benzoates and the electron ionization mass spectra of the acetates and the tri-O-methyl derivative are reported herein as are the linear temperature programmed gas-liquid chromatography retention indices of the acetates and the tri-O-methyl derivative on three different capillary columns.