Emission spectroscopy of divalent-cation-doped GaN photocatalysts

NASA Astrophysics Data System (ADS)

Hirai, Takeshi; Harada, Takashi; Ikeda, Shigeru; Matsumura, Michio; Saito, Nobuo; Nishiyama, Hiroshi; Inoue, Yasunobu; Harada, Yoshiyuki; Ohno, Nobuhito; Maeda, Kazuhiko; Kubota, Jun; Domen, Kazunari

2011-12-01

Photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectra of GaN particles doped with divalent cations (Mg2+, Zn2+, and Be2+), which promote photocatalytic overall water splitting, were investigated. The PL and TRPL spectra were mainly attributed to donor-acceptor pair recombination between the divalent cation dopants and divalent anion impurities (O2- and S2-) unintentionally introduced from raw materials, which form acceptor and donor levels, respectively. These levels are likely to provide holes and electrons required for photocatalytic reactions, contributing to the photocatalytic activity of the GaN-based photocatalysts for overall water splitting.

Activation by divalent cations of a Ca2+-activated K+ channel from skeletal muscle membrane.

PubMed

Oberhauser, A; Alvarez, O; Latorre, R

1988-07-01

Several divalent cations were studied as agonists of a Ca2+-activated K+ channel obtained from rat muscle membranes and incorporated into planar lipid bilayers. The effect of these agonists on single-channel currents was tested in the absence and in the presence of Ca2+. Among the divalent cations that activate the channel, Ca2+ is the most effective, followed by Cd2+, Sr2+, Mn2+, Fe2+, and Co2+. Mg2+, Ni2+, Ba2+, Cu2+, Zn2+, Hg2+, and Sn2+ are ineffective. The voltage dependence of channel activation is the same for all the divalent cations. The time-averaged probability of the open state is a sigmoidal function of the divalent cation concentration. The sigmoidal curves are described by a dissociation constant K and a Hill coefficient N. The values of these parameters, measured at 80 mV are: N = 2.1, K = 4 X 10(-7) mMN for Ca2+; N = 3.0, K = 0.02 mMN for Cd2+; N = 1.45, K = 0.63 mMN for Sr2+; N = 1.7, K = 0.94 mMN for Mn2+; N = 1.1, K = 3.0 mMN for Fe2+; and N = 1.1 K = 4.35 mMN for Co2+. In the presence of Ca2+, the divalent cations Cd2+, Co2+, Mn2+, Ni2+, and Mg2+ are able to increase the apparent affinity of the channel for Ca2+ and they increase the Hill coefficient in a concentration-dependent fashion. These divalent cations are only effective when added to the cytoplasmic side of the channel. We suggest that these divalent cations can bind to the channel, unmasking new Ca2+ sites.

Analysis of the Expression of Peptide–Major Histocompatibility Complexes Using High Affinity Soluble Divalent T Cell Receptors

PubMed Central

O'Herrin, Sean M.; Lebowitz, Michael S.; Bieler, Joan G.; al-Ramadi, Basel K.; Utz, Ursula; Bothwell, Alfred L.M.; Schneck, Jonathan P.

1997-01-01

Understanding the regulation of cell surface expression of specific peptide–major histocompatibility complex (MHC) complexes is hindered by the lack of direct quantitative analyses of specific peptide–MHC complexes. We have developed a direct quantitative biochemical approach by engineering soluble divalent T cell receptor analogues (TCR–Ig) that have high affinity for their cognate peptide–MHC ligands. The generality of this approach was demonstrated by specific staining of peptide-pulsed cells with two different TCR–Ig complexes: one specific for the murine alloantigen 2C, and one specific for a viral peptide from human T lymphocyte virus–1 presented by human histocompatibility leukocyte antigens–A2. Further, using 2C TCR– Ig, a more detailed analysis of the interaction with cognate peptide–MHC complexes revealed several interesting findings. Soluble divalent 2C TCR–Ig detected significant changes in the level of specific antigenic–peptide MHC cell surface expression in cells treated with γ-interferon (γ-IFN). Interestingly, the effects of γ-IFN on expression of specific peptide–MHC complexes recognized by 2C TCR–Ig were distinct from its effects on total H-2 Ld expression; thus, lower doses of γ-IFN were required to increase expression of cell surface class I MHC complexes than were required for upregulation of expression of specific peptide–MHC complexes. Analysis of the binding of 2C TCR–Ig for specific peptide–MHC ligands unexpectedly revealed that the affinity of the 2C TCR–Ig for the naturally occurring alloreactive, putatively, negatively selecting, complex, dEV-8–H-2 Kbm3, is very low, weaker than 71 μM. The affinity of the 2C TCR for the other naturally occurring, negatively selecting, alloreactive complex, p2Ca–H-2 Ld, is ∼1000-fold higher. Thus, negatively selecting peptide–MHC complexes do not necessarily have intrinsically high affinity for cognate TCR. These results, uniquely revealed by this analysis, indicate the importance of using high affinity biologically relevant cognates, such as soluble divalent TCR, in furthering our understanding of immune responses. PMID:9334373

Determination of the nitrogen vacancy as a shallow compensating center in GaN doped with divalent metals.

PubMed

Buckeridge, J; Catlow, C R A; Scanlon, D O; Keal, T W; Sherwood, P; Miskufova, M; Walsh, A; Woodley, S M; Sokol, A A

2015-01-09

We report accurate energetics of defects introduced in GaN on doping with divalent metals, focusing on the technologically important case of Mg doping, using a model that takes into consideration both the effect of hole localization and dipolar polarization of the host material, and includes a well-defined reference level. Defect formation and ionization energies show that divalent dopants are counterbalanced in GaN by nitrogen vacancies and not by holes, which explains both the difficulty in achieving p-type conductivity in GaN and the associated major spectroscopic features, including the ubiquitous 3.46 eV photoluminescence line, a characteristic of all lightly divalent-metal-doped GaN materials that has also been shown to occur in pure GaN samples. Our results give a comprehensive explanation for the observed behavior of GaN doped with low concentrations of divalent metals in good agreement with relevant experiment.

Determination of the Nitrogen Vacancy as a Shallow Compensating Center in GaN Doped with Divalent Metals

NASA Astrophysics Data System (ADS)

Buckeridge, J.; Catlow, C. R. A.; Scanlon, D. O.; Keal, T. W.; Sherwood, P.; Miskufova, M.; Walsh, A.; Woodley, S. M.; Sokol, A. A.

2015-01-01

We report accurate energetics of defects introduced in GaN on doping with divalent metals, focusing on the technologically important case of Mg doping, using a model that takes into consideration both the effect of hole localization and dipolar polarization of the host material, and includes a well-defined reference level. Defect formation and ionization energies show that divalent dopants are counterbalanced in GaN by nitrogen vacancies and not by holes, which explains both the difficulty in achieving p -type conductivity in GaN and the associated major spectroscopic features, including the ubiquitous 3.46 eV photoluminescence line, a characteristic of all lightly divalent-metal-doped GaN materials that has also been shown to occur in pure GaN samples. Our results give a comprehensive explanation for the observed behavior of GaN doped with low concentrations of divalent metals in good agreement with relevant experiment.

Teacher-to-Teacher: An Annotated Bibliography on DNA and Genetic Engineering.

ERIC Educational Resources Information Center

Mertens, Thomas R., Comp.

1984-01-01

Presented is an annotated bibliography of 24 books on DNA and genetic engineering. Areas considered in these books include: basic biological concepts to help understand advances in genetic engineering; applications of genetic engineering; social, legal, and moral issues of genetic engineering; and historical aspects leading to advances in…

Increasing Mechanical Strength of Gelatin Hydrogels by Divalent Metal Ion Removal

PubMed Central

Xing, Qi; Yates, Keegan; Vogt, Caleb; Qian, Zichen; Frost, Megan C.; Zhao, Feng

2014-01-01

The usage of gelatin hydrogel is limited due to its instability and poor mechanical properties, especially under physiological conditions. Divalent metal ions present in gelatin such as Ca2+ and Fe2+ play important roles in the gelatin molecule interactions. The objective of this study was to determine the impact of divalent ion removal on the stability and mechanical properties of gelatin gels with and without chemical crosslinking. The gelatin solution was purified by Chelex resin to replace divalent metal ions with sodium ions. The gel was then chemically crosslinked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Results showed that the removal of divalent metal ions significantly impacted the formation of the gelatin network. The purified gelatin hydrogels had less interactions between gelatin molecules and form larger-pore network which enabled EDC to penetrate and crosslink the gel more efficiently. The crosslinked purified gels showed small swelling ratio, higher crosslinking density and dramatically increased storage and loss moduli. The removal of divalent ions is a simple yet effective method that can significantly improve the stability and strength of gelatin hydrogels. The in vitro cell culture demonstrated that the purified gelatin maintained its ability to support cell attachment and spreading. PMID:24736500

SIMILAR PATTERNS OF MITOCHONDRIAL VULNERABILITY AND RESCUE INDUCED BY GENETIC MODIFICATION OF α-SYNUCLEIN, PARKIN AND DJ-1 IN C. ELEGANS*

PubMed Central

Westlund, Beth; Perier, Celine; Burnam, Lucinda; Sluder, Anne; Hoener, Marius; Rodrigues, Cecilia MP; Alfonso, Aixa; Steer, Clifford; Liu, Leo; Przedborski, Serge; Wolozin, Benjamin

2014-01-01

How genetic and environmental factors interact in Parkinson’s disease is poorly understood. We have now compared the patterns of vulnerability and rescue of C. elegans with genetic modifications of three different genetic factors implicated in PD. We observed that expressing α-synuclein, deleting parkin (K08E3.7) or knocking down DJ-1 (B0432.2) or parkin, produces similar patterns of pharmacological vulnerability and rescue. C. elegans lines with these genetic changes were more vulnerable than non-transgenic nematodes to mitochondrial complex I inhibitors, including rotenone, fenperoximate, pyridaben or stigmatellin. In contrast, the genetic manipulations did not increase sensitivity to paraquat, sodium azide, divalent metal ions (FeII or CuII) or etoposide compared to non-transgenic nematodes. Each of the PD-related lines was also partially rescued by the anti-oxidant probucol, the mitochondrial complex II activator, D-β-hydroxybutyrate (DβHB) or the anti-apoptotic bile acid tauroursodeoxycholic acid (TUDCA). Complete protection in all lines was achieved by combining DβHB with TUDCA but not with probucol. These results show that diverse PD-related genetic modifications disrupt mitochondrial function in C. elegans, and they raise the possibility that mitochondrial disruption is a pathway shared in common by many types of familial PD. PMID:16239214

Nonspecific uptake and homeostasis drive the oceanic cadmium cycle

NASA Astrophysics Data System (ADS)

Horner, Tristan J.; Lee, Renee B. Y.; Henderson, Gideon M.; Rickaby, Rosalind E. M.

2013-02-01

The global marine distributions of Cd and phosphate are closely correlated, which has led to Cd being considered as a marine micronutrient, despite its toxicity to life. The explanation for this nutrient-like behavior is unknown because there is only one identified biochemical function for Cd, an unusual Cd/Zn carbonic anhydrase. Recent developments in Cd isotope mass spectrometry have revealed that Cd uptake by phytoplankton causes isotopic fractionation in the open ocean and in culture. Here we investigate the physiochemical pathways that fractionate Cd isotopes by performing subcellular Cd isotope analysis on genetically modified microorganisms. We find that expression of the Cd/Zn carbonic anhydrase makes no difference to the Cd isotope composition of whole cells. Instead, a large proportion of the Cd is partitioned into cell membranes with a similar direction and magnitude of Cd isotopic fractionation to that seen in surface seawater. This observation is well explained if Cd is mistakenly imported with other divalent metals and subsequently managed by binding within the cell to avoid toxicity. This process may apply to other divalent metals, whereby nonspecific uptake and subsequent homeostasis may contribute to elemental and isotopic distributions in seawater, even for elements commonly considered as micronutrients.

Modulating macrophage polarization with divalent cations in nanostructured titanium implant surfaces

NASA Astrophysics Data System (ADS)

Lee, Chung-Ho; Kim, Youn-Jeong; Jang, Je-Hee; Park, Jin-Woo

2016-02-01

Nanoscale topographical modification and surface chemistry alteration using bioactive ions are centrally important processes in the current design of the surface of titanium (Ti) bone implants with enhanced bone healing capacity. Macrophages play a central role in the early tissue healing stage and their activity in response to the implant surface is known to affect the subsequent healing outcome. Thus, the positive modulation of macrophage phenotype polarization (i.e. towards the regenerative M2 rather than the inflammatory M1 phenotype) with a modified surface is essential for the osteogenesis funtion of Ti bone implants. However, relatively few advances have been made in terms of modulating the macrophage-centered early healing capacity in the surface design of Ti bone implants for the two important surface properties of nanotopography and and bioactive ion chemistry. We investigated whether surface bioactive ion modification exerts a definite beneficial effect on inducing regenerative M2 macrophage polarization when combined with the surface nanotopography of Ti. Our results indicate that nanoscale topographical modification and surface bioactive ion chemistry can positively modulate the macrophage phenotype in a Ti implant surface. To the best of our knowledge, this is the first demonstration that chemical surface modification using divalent cations (Ca and Sr) dramatically induces the regenerative M2 macrophage phenotype of J774.A1 cells in nanostructured Ti surfaces. In this study, divalent cation chemistry regulated the cell shape of adherent macrophages and markedly up-regulated M2 macrophage phenotype expression when combined with the nanostructured Ti surface. These results provide insight into the surface engineering of future Ti bone implants that are harmonized between the macrophage-governed early wound healing process and subsequent mesenchymal stem cell-centered osteogenesis function.

Mesoscale Modeling of Chromatin Folding

NASA Astrophysics Data System (ADS)

Schlick, Tamar

2009-03-01

Eukaryotic chromatin is the fundamental protein/nucleic acid unit that stores the genetic material. Understanding how chromatin fibers fold and unfold in physiological conditions is important for interpreting fundamental biological processes like DNA replication and transcription regulation. Using a mesoscopic model of oligonucleosome chains and tailored sampling protocols, we elucidate the energetics of oligonucleosome folding/unfolding and the role of each histone tail, linker histones, and divalent ions in regulating chromatin structure. The resulting compact topologies reconcile features of the zigzag model with straight linker DNAs with the solenoid model with bent linker DNAs for optimal fiber organization and reveal dynamic and energetic aspects involved.

Use of MgO doped with a divalent or trivalent metal cation for removing arsenic from water

DOEpatents

Moore, Robert C; Holt-Larese, Kathleen C; Bontchev, Ranko

2013-08-13

Systems and methods for use of magnesium hydroxide, either directly or through one or more precursors, doped with a divalent or trivalent metal cation, for removing arsenic from drinking water, including water distribution systems. In one embodiment, magnesium hydroxide, Mg(OH).sub.2 (a strong adsorbent for arsenic) doped with a divalent or trivalent metal cation is used to adsorb arsenic. The complex consisting of arsenic adsorbed on Mg(OH).sub.2 doped with a divalent or trivalent metal cation is subsequently removed from the water by conventional means, including filtration, settling, skimming, vortexing, centrifugation, magnetic separation, or other well-known separation systems. In another embodiment, magnesium oxide, MgO, is employed, which reacts with water to form Mg(OH).sub.2. The resulting Mg(OH).sub.2 doped with a divalent or trivalent metal cation, then adsorbs arsenic, as set forth above. The method can also be used to treat human or animal poisoning with arsenic.

Use of MgO doped with a divalent or trivalent metal cation for removing arsenic from water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Robert C.; Larese, Kathleen Caroline; Bontchev, Ranko Panayotov

Systems and methods for use of magnesium hydroxide, either directly or through one or more precursors, doped with a divalent or trivalent metal cation, for removing arsenic from drinking water, including water distribution systems. In one embodiment, magnesium hydroxide, Mg(OH).sub.2 (a strong adsorbent for arsenic) doped with a divalent or trivalent metal cation is used to adsorb arsenic. The complex consisting of arsenic adsorbed on Mg(OH).sub.2 doped with a divalent or trivalent metal cation is subsequently removed from the water by conventional means, including filtration, settling, skimming, vortexing, centrifugation, magnetic separation, or other well-known separation systems. In another embodiment, magnesiummore » oxide, MgO, is employed, which reacts with water to form Mg(OH).sub.2. The resulting Mg(OH).sub.2 doped with a divalent or trivalent metal cation, then adsorbs arsenic, as set forth above. The method can also be used to treat human or animal poisoning with arsenic.« less

Interaction of divalent minerals with liposoluble nutrients and phytochemicals during digestion and influences on their bioavailability - a review.

PubMed

Corte-Real, Joana; Bohn, Torsten

2018-06-30

Several divalent minerals, including the macroelements calcium and magnesium, are essential nutrients for humans. However, their intake, especially via high-dose supplements, has been suspected to reduce the availability of lipophilic dietary constituents, including lipids, liposoluble vitamins, and several phytochemicals such as carotenoids. These constituents require emulsification in order to be bioavailable, and high divalent mineral concentrations may perturb this process, due to precipitations of free fatty acids or bile salt complexation, both pivotal for mixed micelle formation. Though in part based on in vitro or indirect evidence, it appears likely that high-dose supplements of divalent minerals around or even below their recommended dietary allowance perturb the availability of certain liposoluble miroconstituents, in addition to reducing absorption of dietary lipids/cholesterol. In this review, we investigate possible negative influences of divalent minerals, including trace elements (iron, zinc), on the digestion and intestinal uptake of lipophilic dietary constituents, with a focus on carotenoids. Copyright © 2018 Elsevier Ltd. All rights reserved.

RENAL TUBULAR TRANSPORT OF INORGANIC DIVALENT IONS BY THE AGLOMERULAR MARINE TELEOST, LOPHIUS AMERICANUS

PubMed Central

Berglund, Fredrik; Forster, Roy P.

1958-01-01

A characterization was attempted of the mechanisms involved in the tubular transport of inorganic divalent ions by the aglomerular kidney of Lophius, attention being paid particularly to the possible existence of transport maxima (Tm) and to competition for transport among related substances undergoing tubular excretion. Excretory rates of divalent ions in non-treated fish during standard laboratory conditions paralleled spontaneous changes in urine flow. Tm rates of excretion were reached for magnesium, sulfate, and thiosulfate with corresponding plasma levels of 2 to 5, 5 to 17, and 4 to 12 µM/ml. respectively. Elevation of magnesium chloride levels in plasma markedly depressed calcium excretion; sodium thiosulfate similarly depressed sulfate excretion. Experimental observations suggest the existence of a transport system for divalent cations separate from another for divalent anions. Within each transport system the ion with the higher excretion rate depressed competitively transfer of the other ion. Neither system was influenced by probenecid (benemid) in doses which markedly depressed the simultaneous excretion rate of p-aminohippuric acid. PMID:13491814

Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(II)

DOE PAGES

Dau, Phuong D.; Shuh, David K.; Sturzbecher-Hoehne, Manuel; ...

2016-07-07

The divalent oxidation state is increasingly stable relative to the trivalent state for the later actinide elements, with californium the first actinide to exhibit divalent chemistry under moderate conditions. Although there is evidence for divalent Cf in solution and solid compounds, there are no reports of discrete complexes in which Cf II is coordinated by anionic ligands. Described here is the divalent Cf methanesulfinate coordination complex, Cf II(CH 3SO 2) 3-, prepared in the gas phase by reductive elimination of CH 3SO 2 from Cf III(CH 3SO 2) 4-. Comparison with synthesis of the corresponding Sm and Cm complexes revealsmore » reduction of CfIII and SmIII, and no evidence for reduction of Cm III. This reflects the comparative 3+/2+ reduction potentials: Cf 3+ (-1.60 V) ≈ Sm 3+ (-1.55 V) >> Cm 3+ (-3.7 V). Association of O 2 to the divalent complexes is attributed to formation of superoxides, with recovery of the trivalent oxidation state. Lastly, the new gas-phase chemistry of californium, now the heaviest element to have been studied in this manner, provides evidence for Cf II coordination complexes and similar chemistry of Cf and Sm.« less

Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(II)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dau, Phuong D.; Shuh, David K.; Sturzbecher-Hoehne, Manuel

The divalent oxidation state is increasingly stable relative to the trivalent state for the later actinide elements, with californium the first actinide to exhibit divalent chemistry under moderate conditions. Although there is evidence for divalent Cf in solution and solid compounds, there are no reports of discrete complexes in which Cf II is coordinated by anionic ligands. Described here is the divalent Cf methanesulfinate coordination complex, Cf II(CH 3SO 2) 3-, prepared in the gas phase by reductive elimination of CH 3SO 2 from Cf III(CH 3SO 2) 4-. Comparison with synthesis of the corresponding Sm and Cm complexes revealsmore » reduction of CfIII and SmIII, and no evidence for reduction of Cm III. This reflects the comparative 3+/2+ reduction potentials: Cf 3+ (-1.60 V) ≈ Sm 3+ (-1.55 V) >> Cm 3+ (-3.7 V). Association of O 2 to the divalent complexes is attributed to formation of superoxides, with recovery of the trivalent oxidation state. Lastly, the new gas-phase chemistry of californium, now the heaviest element to have been studied in this manner, provides evidence for Cf II coordination complexes and similar chemistry of Cf and Sm.« less

The permeability of endplate channels to monovalent and divalent metal cations

PubMed Central

1980-01-01

The relative permeability of endplate channels to monovalent and divalent metal ions was determined from reversal potentials. Thallium is the most permeant ion with a permeability ratio relative to Na+ of 2.5. The selectivity among alkali metals is weak with a sequence, Cs+ greater than Rb+ greater than K+ greater than Na+ greater than Li+, and permeability ratios of 1.4, 1.3, 1.1, 1.0, and 0.9. The selectivity among divalent ions is also weak, with a sequence for alkaline earths of Mg++ greater than Ca++ greater than Ba++ greater than Sr++. The transition metal ions Mn++, Co++, Ni++, Zn++, and Cd++ are also permeant. Permeability ratios for divalent ions decreased as the concentration of divalent ion was increased in a manner consistent with the negative surface potential theory of Lewis (1979 J. Physiol. (Lond.). 286: 417--445). With 20 mM XCl2 and 85.5 mM glucosamine.HCl in the external solution, the apparent permeability ratios for the alkaline earth cations (X++) are in the range 0.18--0.25. Alkali metal ions see the endplate channel as a water-filled, neutral pore without high-field-strength sites inside. Their permeability sequence is the same as their aqueous mobility sequence. Divalent ions, however, have a permeability sequence almost opposite from their mobility sequence and must experience some interaction with groups in the channel. In addition, the concentrations of monovalent and divalent ions are increased near the channel mouth by a weak negative surface potential. PMID:6247423

SEPARATION OF EUROPIUM FROM OTHER LANTHANIDE RAE EARTHS BY SOLVENT EXTRACTION

DOEpatents

Peppard, D.F.; Horwitz, E.P.; Mason, G.W.

1963-02-12

This patent deals with a process of separating europium from other lanthanides present in aqueous hydrochloric or sulfuric acid solutions. The europium is selectively reduced to the divalent state with a divalent chromium salt formed in situ from chromium(III) salt plus zinc amalgam. The other trivalent lanthanides are then extracted away from the divalent europium with a nitrogen-flushed phosphoric acid ester or a phosphonic acid ester. (AEC)

78 FR 13286 - Sharing Certain Business Information Regarding the Introduction of Genetically Engineered...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-27

... Information Regarding the Introduction of Genetically Engineered Organisms With State and Tribal Government... proposing to amend our regulations regarding genetically engineered organisms regulated by the United States...). The regulations refer to such genetically engineered (GE) organisms and products as ``regulated...

Production of iota toxin by Clostridium spiroforme: a requirement for divalent cations.

PubMed

Carman, R J; van Tassell, R L; Wilkins, T D

1987-10-01

The effects of divalent cations (Ca2+, Co2+ and Zn2+) on the production of iota toxin by Clostridium spiroforme were studied. Toxin production had an absolute requirement for one or more cations in the range 1-5 mM. Using bispecific antisera, we showed that production of both the components of the toxin (ia and ib) were enhanced by divalent cations added to brain-heart infusion supplemented with peptone and glucose.

76 FR 8707 - Syngenta Seeds, Inc.; Determination of Nonregulated Status for Corn Genetically Engineered To...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-15

... for Corn Genetically Engineered To Produce an Enzyme That Facilitates Ethanol Production AGENCY... event 3272, which has been genetically engineered to produce a microbial enzyme that facilitates ethanol... transformation event 3272, which has been genetically engineered to produce a microbial enzyme that facilitates...

Data in support of the negative influence of divalent cations on (−)-epigallocatechin-3-gallate (EGCG)-mediated inhibition of matrix metalloproteinase-2 (MMP-2)

PubMed Central

Deb, Gauri; Batra, Sahil; Limaye, Anil M.

2015-01-01

In this data article we have provided evidence for the negative influence of divalent cations on (−)‐epigallocatechin-3-gallate (EGCG)-mediated inhibition of matrix metalloproteinase-2 (MMP-2) activity in cell-free experiments. Chelating agents, such as EDTA and sodium citrate alone, did not affect MMP-2 activity. While EDTA enhanced, excess of divalent cations interfered with EGCG-mediated inhibition of MMP-2. PMID:26977427

76 FR 63278 - Bayer CropScience LP; Determination of Nonregulated Status for Cotton Genetically Engineered for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-12

... for Cotton Genetically Engineered for Insect Resistance and Herbicide Tolerance AGENCY: Animal and... determination that a genetically engineered cotton developed by Bayer CropScience LP, designated as TwinLink TM cotton (events T304-40 and GHB119), which has been genetically engineered to be tolerant to the herbicide...

Seeking perfection: a Kantian look at human genetic engineering.

PubMed

Gunderson, Martin

2007-01-01

It is tempting to argue that Kantian moral philosophy justifies prohibiting both human germ-line genetic engineering and non-therapeutic genetic engineering because they fail to respect human dignity. There are, however, good reasons for resisting this temptation. In fact, Kant's moral philosophy provides reasons that support genetic engineering-even germ-line and non-therapeutic. This is true of Kant's imperfect duties to seek one's own perfection and the happiness of others. It is also true of the categorical imperative. Kant's moral philosophy does, however, provide limits to justifiable genetic engineering.

Modularization of genetic elements promotes synthetic metabolic engineering.

PubMed

Qi, Hao; Li, Bing-Zhi; Zhang, Wen-Qian; Liu, Duo; Yuan, Ying-Jin

2015-11-15

In the context of emerging synthetic biology, metabolic engineering is moving to the next stage powered by new technologies. Systematical modularization of genetic elements makes it more convenient to engineer biological systems for chemical production or other desired purposes. In the past few years, progresses were made in engineering metabolic pathway using synthetic biology tools. Here, we spotlighted the topic of implementation of modularized genetic elements in metabolic engineering. First, we overviewed the principle developed for modularizing genetic elements and then discussed how the genetic modules advanced metabolic engineering studies. Next, we picked up some milestones of engineered metabolic pathway achieved in the past few years. Last, we discussed the rapid raised synthetic biology field of "building a genome" and the potential in metabolic engineering. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of Zinc Gluconate and 2 Other Divalent Cationic Compounds on Olfactory Function in Mice

PubMed Central

Duncan-Lewis, Christopher A; Lukman, Roy L; Banks, Robert K

2011-01-01

Intranasal application of zinc gluconate has commonly been used to treat the common cold. The safety of this treatment, however, has come into question recently. In addition to a United States recall of a homeopathic product that contains zinc gluconate, abundant literature reports cytotoxic effects of zinc on the olfactory epithelium. Additional research suggests that divalent cations (such as zinc) can block ion channels that facilitate the transduction of odors into electrical signals on the olfactory epithelium. The purpose of the current study was 2-fold: to confirm whether zinc gluconate causes anosmia and to reveal whether any other divalent cationic compounds produce a similar effect. Groups of mice underwent a buried food-pellet test to gauge olfactory function and then were nasally irrigated with 1 of 3 divalent cationic compounds. When tested after treatment, mice irrigated with zinc gluconate and copper gluconate experienced a marked increase in food-finding time, indicating that they had lost their ability to smell a hidden food source. Control mice irrigated with saline had a significantly lower increase in times. These results confirm that zinc gluconate can cause anosmia and reveal that multiple divalent cations can negatively affect olfaction. PMID:22330252

Structure of an electric double layer containing a 2:2 valency dimer electrolyte

DOE PAGES

Silvestre-Alcantara, Whasington; Henderson, Douglas; Wu, Jianzhong; ...

2014-12-05

In this study, the structure of a planar electric double layer formed by a 2:2 valency dimer electrolyte in the vicinity of a uniformly charged planar hard electrode is investigated using density functional theory and Monte Carlo simulations. The dimer electrolyte consists of a mixture of charged divalent dimers and charged divalent monomers in a dielectric continuum. A dimer is constructed by two tangentially tethered rigid spheres, one of which is divalent and positively charged and the other neutral, whereas the monomer is a divalent and negatively charged rigid sphere. The density functional theory reproduces well the simulation results formore » (i) the singlet distributions of the various ion species with respect to the electrode, and (ii) the mean electrostatic potential. Lastly, comparison with earlier results for a 2:1/1:2 dimer electrolyte shows that the double layer structure is similar when the counterion has the same valency.« less

DESCRIPTIVE ANALYSIS OF DIVALENT SALTS

PubMed Central

YANG, HEIDI HAI-LING; LAWLESS, HARRY T.

2005-01-01

Many divalent salts (e.g., calcium, iron, zinc), have important nutritional value and are used to fortify food or as dietary supplements. Sensory characterization of some divalent salts in aqueous solutions by untrained judges has been reported in the psychophysical literature, but formal sensory evaluation by trained panels is lacking. To provide this information, a trained descriptive panel evaluated the sensory characteristics of 10 divalent salts including ferrous sulfate, chloride and gluconate; calcium chloride, lactate and glycerophosphate; zinc sulfate and chloride; and magnesium sulfate and chloride. Among the compounds tested, iron compounds were highest in metallic taste; zinc compounds had higher astringency and a glutamate-like sensation; and bitterness was pronounced for magnesium and calcium salts. Bitterness was affected by the anion in ferrous and calcium salts. Results from the trained panelists were largely consistent with the psychophysical literature using untrained judges, but provided a more comprehensive set of oral sensory attributes. PMID:16614749

Effects of ionic compositions of the medium on monosodium glutamate binding to taste epithelial cells.

PubMed

Hayashi, Y; Tsunenari, T; Mori, T

1999-03-01

Monosodium glutamate and nucleotides are umami taste substances in animals and have a synergistic effect on each other. We studied the ligand-binding properties of the glutamate receptors in taste epithelial cells isolated from bovine tongue. Specific glutamate binding was observed in an enriched suspension of taste receptor cells in Hanks' balanced salt solution, while no specific glutamate binding was apparent in the absence of divalent ions or when the cells had been depolarized by a high content of potassium in Hanks' balanced salt solution. There was no significant difference between the release of glutamate under depolarized or divalent ion-free conditions and under normal conditions. However, glutamate was easily released from the depolarized cells in the absence of divalent ions. These data suggest that the binding of glutamate to receptors depends on divalent ions, which also have an effect on maintaining binding between glutamate and receptors.

Multisite occupation of divalent dopants in barium and strontium titanates

NASA Astrophysics Data System (ADS)

Zulueta, Yohandys A.; Nguyen, Minh Tho

2018-10-01

Based on recent experimental and theoretical proofs of calcium multisite occupation in barium titanate, we investigated a mixed incorporation mechanism for divalent dopants in barium and strontium titanates (BaTiO3 and SrTiO3). Our present theoretical results demonstrated the multisite occupation of divalent dopants in both perovskite structures. We determined the dependences of the solution, binding energies, and final solution energies with respect to the ionic radii of the dopants. Calculated results obtained based on classical simulations showed that the divalent dopants can occupy both A- and Ti- cation sites in ATiO3 perovskite structures. Such a multisite occupation has direct implications for other experimental findings regarding BaTiO3, such as non-stabilization of the tetragonal phase, shifts in the Curie temperature, intensification of the diffuse phase transition, and shifts in the absorption of ultraviolet light to the visible range in photocatalytic applications related to solar cells for producing energy.

Malic enzyme: Tritium isotope effects with alternative dinucleotide substrates and divalent metal ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karsten, W.E.; Harris, B.G.; Cook, P.F.

1992-01-01

The NAD-malic enzyme from Ascaris suum catalyzes the divalent metal ion dependent oxidative decarboxylation of L-malate to yield pyruvate, carbon dioxide and NADH. Multiple isotope effect studies suggest a stepwise chemical mechanism with hydride transfer from L-malate to NAD occurring first to form oxalacetate, followed by decarboxylation. Utilizing L-malate-2-T, tritium V/K isotope effects have been determined for the hydride transfer step using a variety of alternative dinucleotide substrates and divalent metal ions. Combination of these data with deuterium isotope effects data and previously determined [sup 13]C isotope effects has allowed the calculation of intrinsic isotope effects for the malic enzymemore » catalyzed reaction. The identity of both the dinucleotide substrate and divalent metal ion has an effect of the size of the intrinsic isotope effect for hydride transfer.« less

Engineering of the function of diamond-like carbon binding peptides through structural design.

PubMed

Gabryelczyk, Bartosz; Szilvay, Géza R; Singh, Vivek K; Mikkilä, Joona; Kostiainen, Mauri A; Koskinen, Jari; Linder, Markus B

2015-02-09

The use of phage display to select material-specific peptides provides a general route towards modification and functionalization of surfaces and interfaces. However, a rational structural engineering of the peptides for optimal affinity is typically not feasible because of insufficient structure-function understanding. Here, we investigate the influence of multivalency of diamond-like carbon (DLC) binding peptides on binding characteristics. We show that facile linking of peptides together using different lengths of spacers and multivalency leads to a tuning of affinity and kinetics. Notably, increased length of spacers in divalent systems led to significantly increased affinities. Making multimers influenced also kinetic aspects of surface competition. Additionally, the multivalent peptides were applied as surface functionalization components for a colloidal form of DLC. The work suggests the use of a set of linking systems to screen parameters for functional optimization of selected material-specific peptides.

Genetic engineering possibilities for CELSS: A bibliography and summary of techniques

NASA Technical Reports Server (NTRS)

Johnson, E. J.

1982-01-01

A bibliography of the most useful techniques employed in genetic engineering of higher plants, bacteria associated with plants, and plant cell cultures is provided. A resume of state-of-the-art genetic engineering of plants and bacteria is presented. The potential application of plant bacterial genetic engineering to CELSS (Controlled Ecological Life Support System) program and future research needs are discussed.

77 FR 41366 - Syngenta Biotechnology, Inc.; Availability of Petition, Plant Pest Risk Assessment, and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... engineered organisms and products. We are soliciting comments on whether this genetically engineered corn is... pests. Such genetically engineered organisms and products are considered ``regulated articles.'' The... Assessment for Determination of Nonregulated Status of Corn Genetically Engineered for Insect Resistance...

Selected Readings in Genetic Engineering

ERIC Educational Resources Information Center

Mertens, Thomas R.; Robinson, Sandra K.

1973-01-01

Describes different sources of readings for understanding issues and concepts of genetic engineering. Broad categories of reading materials are: concerns about genetic engineering; its background; procedures; and social, ethical and legal issues. References are listed. (PS)

Engineered Intrinsic Bioremediation of Ammonium Perchlorate in Groundwater

DTIC Science & Technology

2010-12-01

German Collection of Microorganisms and Cell Cultures) GA Genetic Algorithms GA-ANN Genetic Algorithm Artificial Neural Network GMO genetically...for in situ treatment of perchlorate in groundwater. This is accomplished without the addition of genetically engineered microorganisms ( GMOs ) to the...perchlorate, even in the presence of oxygen and without the addition of genetically engineered microorganisms ( GMOs ) to the environment. This approach

Block by Extracellular Divalent Cations of Drosophila Big Brain Channels Expressed in Xenopus Oocytes

PubMed Central

Yanochko, Gina M.; Yool, Andrea J.

2004-01-01

Drosophila Big Brain (BIB) is a transmembrane protein encoded by the neurogenic gene big brain (bib), which is important for early development of the fly nervous system. BIB expressed in Xenopus oocytes is a monovalent cation channel modulated by tyrosine kinase signaling. Results here demonstrate that the BIB conductance shows voltage- and dose-dependent block by extracellular divalent cations Ca2+ and Ba2+ but not by Mg2+ in wild-type channels. Site-directed mutagenesis of negatively charged glutamate (Glu274) and aspartate (Asp253) residues had no effect on divalent cation block. However, mutation of a conserved glutamate at position 71 (Glu71) in the first transmembrane domain (M1) altered channel properties. Mutation of Glu71 to Asp introduced a new sensitivity to block by extracellular Mg2+; substitutions with asparagine or glutamine decreased whole-cell conductance; and substitution with lysine compromised plasma membrane expression. Block by divalent cations is important in other ion channels for voltage-dependent function, enhanced signal resolution, and feedback regulation. Our data show that the wild-type BIB conductance is attenuated by external Ca2+, suggesting that endogenous divalent cation block might be relevant for enhancing signal resolution or voltage dependence for the native signaling process in neuronal cell fate determination. PMID:14990474

Commercialising genetically engineered animal biomedical products.

PubMed

Sullivan, Eddie J; Pommer, Jerry; Robl, James M

2008-01-01

Research over the past two decades has increased the quality and quantity of tools available to produce genetically engineered animals. The number of potentially viable biomedical products from genetically engineered animals is increasing. However, moving from cutting-edge research to development and commercialisation of a biomedical product that is useful and wanted by the public has significant challenges. Even early stage development of genetically engineered animal applications requires consideration of many steps, including quality assurance and quality control, risk management, gap analysis, founder animal establishment, cell banking, sourcing of animals and animal-derived material, animal facilities, product collection facilities and processing facilities. These steps are complicated and expensive. Biomedical applications of genetically engineered animals have had some recent successes and many applications are well into development. As researchers consider applications for their findings, having a realistic understanding of the steps involved in the development and commercialisation of a product, produced in genetically engineered animals, is useful in determining the risk of genetic modification to the animal nu. the potential public benefit of the application.

76 FR 78232 - Monsanto Co.; Determination of Nonregulated Status for Soybean Genetically Engineered To Have a...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-16

... peer review of safety tests, and health effects of genetically modified organisms and glyphosate. APHIS...] Monsanto Co.; Determination of Nonregulated Status for Soybean Genetically Engineered To Have a Modified... that there is reason to believe are plant pests. Such genetically engineered organisms and products are...

What Ideas Do Students Associate with "Biotechnology" and "Genetic Engineering"?

ERIC Educational Resources Information Center

Hill, Ruaraidh; Stanisstreet, Martin; Boyes, Edward

2000-01-01

Explores the ideas that students aged 16-19 associate with the terms 'biotechnology' and 'genetic engineering'. Indicates that some students see biotechnology as risky whereas genetic engineering was described as ethically wrong. (Author/ASK)

76 FR 39812 - Scotts Miracle-Gro Co.; Regulatory Status of Kentucky Bluegrass Genetically Engineered for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-07

...] Scotts Miracle-Gro Co.; Regulatory Status of Kentucky Bluegrass Genetically Engineered for Herbicide... engineered for herbicide tolerance without the use of plant pest components, does not meet the definition of... has been genetically engineered for herbicide tolerance, does not meet the definition of a regulated...

Genetic engineering applied to agriculture has a long row to hoe.

PubMed

Miller, Henry I

2018-01-02

In spite of the lack of scientific justification for skepticism about crops modified with molecular techniques of genetic engineering, they have been the most scrutinized agricultural products in human history. The assumption that "genetically engineered" or "genetically modified" is a meaningful - and dangerous - classification has led to excessive and dilatory regulation. The modern molecular techniques are an extension, or refinement, of older, less precise, less predictable methods of genetic modification, but as long as today's activists and regulators remain convinced that so called "GMOs" represent a distinct and dangerous category of research and products, genetic engineering will fall short of its potential.

Novel DOTA-based prochelator for divalent peptide vectorization: synthesis of dimeric bombesin analogues for multimodality tumor imaging and therapy.

PubMed

Abiraj, Keelara; Jaccard, Hugues; Kretzschmar, Martin; Helm, Lothar; Maecke, Helmut R

2008-07-28

Dimeric peptidic vectors, obtained by the divalent grafting of bombesin analogues on a newly synthesized DOTA-based prochelator, showed improved qualities as tumor targeted imaging probes in comparison to their monomeric analogues.

Microfluidic Bioprinting for Engineering Vascularized Tissues and Organoids.

PubMed

Zhang, Yu Shrike; Pi, Qingmeng; van Genderen, Anne Metje

2017-08-11

Engineering vascularized tissue constructs and organoids has been historically challenging. Here we describe a novel method based on microfluidic bioprinting to generate a scaffold with multilayer interlacing hydrogel microfibers. To achieve smooth bioprinting, a core-sheath microfluidic printhead containing a composite bioink formulation extruded from the core flow and the crosslinking solution carried by the sheath flow, was designed and fitted onto the bioprinter. By blending gelatin methacryloyl (GelMA) with alginate, a polysaccharide that undergoes instantaneous ionic crosslinking in the presence of select divalent ions, followed by a secondary photocrosslinking of the GelMA component to achieve permanent stabilization, a microfibrous scaffold could be obtained using this bioprinting strategy. Importantly, the endothelial cells encapsulated inside the bioprinted microfibers can form the lumen-like structures resembling the vasculature over the course of culture for 16 days. The endothelialized microfibrous scaffold may be further used as a vascular bed to construct a vascularized tissue through subsequent seeding of the secondary cell type into the interstitial space of the microfibers. Microfluidic bioprinting provides a generalized strategy in convenient engineering of vascularized tissues at high fidelity.

Genetic Engineering

ERIC Educational Resources Information Center

Phillips, John

1973-01-01

Presents a review of genetic engineering, in which the genotypes of plants and animals (including human genotypes) may be manipulated for the benefit of the human species. Discusses associated problems and solutions and provides an extensive bibliography of literature relating to genetic engineering. (JR)

Effect of Divalent Cation Removal on the Structure of Gram-Negative Bacterial Outer Membrane Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clifton, Luke A.; Skoda, Maximilian W. A.; Le Brun, Anton P.

The Gram-negative bacterial outer membrane (GNB-OM) is asymmetric in its lipid composition with a phospholipid-rich inner leaflet and an outer leaflet predominantly composed of lipopolysaccharides (LPS). LPS are polyanionic molecules, with numerous phosphate groups present in the lipid A and core oligosaccharide regions. The repulsive forces due to accumulation of the negative charges are screened and bridged by the divalent cations (Mg 2+ and Ca 2+) that are known to be crucial for the integrity of the bacterial OM. Indeed, chelation of divalent cations is a well-established method to permeabilize Gram-negative bacteria such as Escherichia coli. Here, we use X-raymore » and neutron reflectivity (XRR and NR, respectively) techniques to examine the role of calcium ions in the stability of a model GNB-OM. Using XRR we show that Ca 2+ binds to the core region of the rough mutant LPS (RaLPS) films, producing more ordered structures in comparison to divalent cation free monolayers. Using recently developed solid-supported models of the GNB-OM, we study the effect of calcium removal on the asymmetry of DPPC:RaLPS bilayers. We show that without the charge screening effect of divalent cations, the LPS is forced to overcome the thermodynamically unfavorable energy barrier and flip across the hydrophobic bilayer to minimize the repulsive electrostatic forces, resulting in about 20% mixing of LPS and DPPC between the inner and outer bilayer leaflets. These results reveal for the first time the molecular details behind the well-known mechanism of outer membrane stabilization by divalent cations. This confirms the relevance of the asymmetric models for future studies of outer membrane stability and antibiotic penetration.« less

Fluorescent Protein-Based Ca2+ Sensor Reveals Global, Divalent Cation-Dependent Conformational Changes in Cardiac Troponin C.

PubMed

Badr, Myriam A; Pinto, Jose R; Davidson, Michael W; Chase, P Bryant

2016-01-01

Cardiac troponin C (cTnC) is a key effector in cardiac muscle excitation-contraction coupling as the Ca2+ sensing subunit responsible for controlling contraction. In this study, we generated several FRET sensors for divalent cations based on cTnC flanked by a donor fluorescent protein (CFP) and an acceptor fluorescent protein (YFP). The sensors report Ca2+ and Mg2+ binding, and relay global structural information about the structural relationship between cTnC's N- and C-domains. The sensors were first characterized using end point titrations to decipher the response to Ca2+ binding in the presence or absence of Mg2+. The sensor that exhibited the largest responses in end point titrations, CTV-TnC, (Cerulean, TnC, and Venus) was characterized more extensively. Most of the divalent cation-dependent FRET signal originates from the high affinity C-terminal EF hands. CTV-TnC reconstitutes into skinned fiber preparations indicating proper assembly of troponin complex, with only ~0.2 pCa unit rightward shift of Ca2+-sensitive force development compared to WT-cTnC. Affinity of CTV-TnC for divalent cations is in agreement with known values for WT-cTnC. Analytical ultracentrifugation indicates that CTV-TnC undergoes compaction as divalent cations bind. C-terminal sites induce ion-specific (Ca2+ versus Mg2+) conformational changes in cTnC. Our data also provide support for the presence of additional, non-EF-hand sites on cTnC for Mg2+ binding. In conclusion, we successfully generated a novel FRET-Ca2+ sensor based on full length cTnC with a variety of cellular applications. Our sensor reveals global structural information about cTnC upon divalent cation binding.

Effect of Divalent Cation Removal on the Structure of Gram-Negative Bacterial Outer Membrane Models

DOE PAGES

Clifton, Luke A.; Skoda, Maximilian W. A.; Le Brun, Anton P.; ...

2014-12-09

The Gram-negative bacterial outer membrane (GNB-OM) is asymmetric in its lipid composition with a phospholipid-rich inner leaflet and an outer leaflet predominantly composed of lipopolysaccharides (LPS). LPS are polyanionic molecules, with numerous phosphate groups present in the lipid A and core oligosaccharide regions. The repulsive forces due to accumulation of the negative charges are screened and bridged by the divalent cations (Mg 2+ and Ca 2+) that are known to be crucial for the integrity of the bacterial OM. Indeed, chelation of divalent cations is a well-established method to permeabilize Gram-negative bacteria such as Escherichia coli. Here, we use X-raymore » and neutron reflectivity (XRR and NR, respectively) techniques to examine the role of calcium ions in the stability of a model GNB-OM. Using XRR we show that Ca 2+ binds to the core region of the rough mutant LPS (RaLPS) films, producing more ordered structures in comparison to divalent cation free monolayers. Using recently developed solid-supported models of the GNB-OM, we study the effect of calcium removal on the asymmetry of DPPC:RaLPS bilayers. We show that without the charge screening effect of divalent cations, the LPS is forced to overcome the thermodynamically unfavorable energy barrier and flip across the hydrophobic bilayer to minimize the repulsive electrostatic forces, resulting in about 20% mixing of LPS and DPPC between the inner and outer bilayer leaflets. These results reveal for the first time the molecular details behind the well-known mechanism of outer membrane stabilization by divalent cations. This confirms the relevance of the asymmetric models for future studies of outer membrane stability and antibiotic penetration.« less

Effect of Divalent Cation Removal on the Structure of Gram-Negative Bacterial Outer Membrane Models

PubMed Central

2014-01-01

The Gram-negative bacterial outer membrane (GNB-OM) is asymmetric in its lipid composition with a phospholipid-rich inner leaflet and an outer leaflet predominantly composed of lipopolysaccharides (LPS). LPS are polyanionic molecules, with numerous phosphate groups present in the lipid A and core oligosaccharide regions. The repulsive forces due to accumulation of the negative charges are screened and bridged by the divalent cations (Mg2+ and Ca2+) that are known to be crucial for the integrity of the bacterial OM. Indeed, chelation of divalent cations is a well-established method to permeabilize Gram-negative bacteria such as Escherichia coli. Here, we use X-ray and neutron reflectivity (XRR and NR, respectively) techniques to examine the role of calcium ions in the stability of a model GNB-OM. Using XRR we show that Ca2+ binds to the core region of the rough mutant LPS (RaLPS) films, producing more ordered structures in comparison to divalent cation free monolayers. Using recently developed solid-supported models of the GNB-OM, we study the effect of calcium removal on the asymmetry of DPPC:RaLPS bilayers. We show that without the charge screening effect of divalent cations, the LPS is forced to overcome the thermodynamically unfavorable energy barrier and flip across the hydrophobic bilayer to minimize the repulsive electrostatic forces, resulting in about 20% mixing of LPS and DPPC between the inner and outer bilayer leaflets. These results reveal for the first time the molecular details behind the well-known mechanism of outer membrane stabilization by divalent cations. This confirms the relevance of the asymmetric models for future studies of outer membrane stability and antibiotic penetration. PMID:25489959

The Potential of Genetic Engineering in Agriculture to Affect Global Stability

DTIC Science & Technology

2013-04-17

manipulation in agriculture is thousands of years old, dating back to man’s first efforts of plant domestication. Over the last 200 years, and especially the...engineering.” In agriculture, genetic engineering describes the science of manipulating the genetic material (DNA) of plants by adding or taking...nature run its course. This paper does not delve into the science or even the raging safety debate over the use of genetic engineering in plants that

Autosomal-Recessive Intellectual Disability with Cerebellar Atrophy Syndrome Caused by Mutation of the Manganese and Zinc Transporter Gene SLC39A8.

PubMed

Boycott, Kym M; Beaulieu, Chandree L; Kernohan, Kristin D; Gebril, Ola H; Mhanni, Aziz; Chudley, Albert E; Redl, David; Qin, Wen; Hampson, Sarah; Küry, Sébastien; Tetreault, Martine; Puffenberger, Erik G; Scott, James N; Bezieau, Stéphane; Reis, André; Uebe, Steffen; Schumacher, Johannes; Hegele, Robert A; McLeod, D Ross; Gálvez-Peralta, Marina; Majewski, Jacek; Ramaekers, Vincent T; Nebert, Daniel W; Innes, A Micheil; Parboosingh, Jillian S; Abou Jamra, Rami

2015-12-03

Manganese (Mn) and zinc (Zn) are essential divalent cations used by cells as protein cofactors; various human studies and animal models have demonstrated the importance of Mn and Zn for development. Here we describe an autosomal-recessive disorder in six individuals from the Hutterite community and in an unrelated Egyptian sibpair; the disorder is characterized by intellectual disability, developmental delay, hypotonia, strabismus, cerebellar atrophy, and variable short stature. Exome sequencing in one affected Hutterite individual and the Egyptian family identified the same homozygous variant, c.112G>C (p.Gly38Arg), affecting a conserved residue of SLC39A8. The affected Hutterite and Egyptian individuals did not share an extended common haplotype, suggesting that the mutation arose independently. SLC39A8 is a member of the solute carrier gene family known to import Mn, Zn, and other divalent cations across the plasma membrane. Evaluation of these two metal ions in the affected individuals revealed variably low levels of Mn and Zn in blood and elevated levels in urine, indicating renal wasting. Our findings identify a human Mn and Zn transporter deficiency syndrome linked to SLC39A8, providing insight into the roles of Mn and Zn homeostasis in human health and development. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Effect of divalent ions on the optical emission behavior of protein thin films

NASA Astrophysics Data System (ADS)

Bhowal, Ashim Chandra; Kundu, Sarathi

2016-05-01

Photoluminescence behaviors of proteinthin film, bovine serum albumin (BSA) have been studied in the presence of three divalent ions (Mg2+, Ca2+ and Ba2+) at different temperatures using fluorescence spectroscopy. Film thickness and morphology have been studied using atomic force microscopy. Variation of different physicochemical parameters like temperature, solvent polarity, pH, ionic strength, substrate binding etc. can make conformational changes in the protein structure and hence influences the emission behavior.In thin film conformation of BSA, dynamic quenching behavior has beenidentified in the presence of all the three divalent ions at pH≈ 5.5. Depending upon the charge density of the divalent ions interaction with protein molecules modifies and as a result quenching efficiency varies. Also after heat treatment, conformation of the protein molecules changes and as a result the quenching efficiency enhances than that of the unheated films. Studies on such protein-ion interactions and conformational variation may explore various functions of protein when it will adsorb on soft surfaces like membranes, vesicles, etc.

Divalent cation shrinks DNA but inhibits its compaction with trivalent cation.

PubMed

Tongu, Chika; Kenmotsu, Takahiro; Yoshikawa, Yuko; Zinchenko, Anatoly; Chen, Ning; Yoshikawa, Kenichi

2016-05-28

Our observation reveals the effects of divalent and trivalent cations on the higher-order structure of giant DNA (T4 DNA 166 kbp) by fluorescence microscopy. It was found that divalent cations, Mg(2+) and Ca(2+), inhibit DNA compaction induced by a trivalent cation, spermidine (SPD(3+)). On the other hand, in the absence of SPD(3+), divalent cations cause the shrinkage of DNA. As the control experiment, we have confirmed the minimum effect of monovalent cation, Na(+) on the DNA higher-order structure. We interpret the competition between 2+ and 3+ cations in terms of the change in the translational entropy of the counterions. For the compaction with SPD(3+), we consider the increase in translational entropy due to the ion-exchange of the intrinsic monovalent cations condensing on a highly charged polyelectrolyte, double-stranded DNA, by the 3+ cations. In contrast, the presence of 2+ cation decreases the gain of entropy contribution by the ion-exchange between monovalent and 3+ ions.

DECOMPOSTION OF GENETICALLY ENGINEERED TOBACCO UNDER FIELD CONDITIONS: PERSISTENCE OF THE PROTEINASE INHIBITOR I PRODUCT AND EFFECTS OF SOIL MICROBIAL RESPIRATION AND PROTOZOA, NEMATODE AND MICROARTHR

EPA Science Inventory

1. To evaluate the potential effects of genetically engineered (transgenic) plants on soil ecosystems, litterbags containing leaves of non-engineered (parental) and transgenic tobacco plants were buried in field plots. The transgenic tobacco plants were genetically engineered to ...

78 FR 44199 - Semiannual Regulatory Agenda, Spring 2013

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-23

..., interstate movement, and environmental release of certain genetically engineered organisms. This rule will... genetically engineered plants and certain other genetically engineered organisms. Timetable: Action Date FR... Citrus Canker; 0579-AC05 Compensation for Certified Citrus Nursery Stock. 17 Introduction of Organisms...

Genetic engineering of industrial strains of Saccharomyces cerevisiae.

PubMed

Le Borgne, Sylvie

2012-01-01

Genetic engineering has been successfully applied to Saccharomyces cerevisiae laboratory strains for different purposes: extension of substrate range, improvement of productivity and yield, elimination of by-products, improvement of process performance and cellular properties, and extension of product range. The potential of genetically engineered yeasts for the massive production of biofuels as bioethanol and other nonfuel products from renewable resources as lignocellulosic biomass hydrolysates has been recognized. For such applications, robust industrial strains of S. cerevisiae have to be used. Here, some relevant genetic and genomic characteristics of industrial strains are discussed in relation to the problematic of the genetic engineering of such strains. General molecular tools applicable to the manipulation of S. cerevisiae industrial strains are presented and examples of genetically engineered industrial strains developed for the production of bioethanol from lignocellulosic biomass are given.

Deficiency in the divalent metal transporter 1 augments bleomycin-induced lung injury

EPA Science Inventory

Exposure to bleomycin can result in an inflammatory lung injury. The biological effect of this anti-neoplastic agent is dependent on its coordination of iron with subsequent oxidant generation. In lung cells, divalent metal transporter 1 (DMT1) can participate in metal transport ...

Crucial role of dynamic linker histone binding and divalent ions for DNA accessibility and gene regulation revealed by mesoscale modeling of oligonucleosomes

PubMed Central

Collepardo-Guevara, Rosana; Schlick, Tamar

2012-01-01

Monte Carlo simulations of a mesoscale model of oligonucleosomes are analyzed to examine the role of dynamic-linker histone (LH) binding/unbinding in high monovalent salt with divalent ions, and to further interpret noted chromatin fiber softening by dynamic LH in monovalent salt conditions. We find that divalent ions produce a fiber stiffening effect that competes with, but does not overshadow, the dramatic softening triggered by dynamic-LH behavior. Indeed, we find that in typical in vivo conditions, dynamic-LH binding/unbinding reduces fiber stiffening dramatically (by a factor of almost 5, as measured by the elasticity modulus) compared with rigidly fixed LH, and also the force needed to initiate chromatin unfolding, making it consistent with those of molecular motors. Our data also show that, during unfolding, divalent ions together with LHs induce linker-DNA bending and DNA–DNA repulsion screening, which guarantee formation of heteromorphic superbeads-on-a-string structures that combine regions of loose and compact fiber independently of the characteristics of the LH–core bond. These structures might be important for gene regulation as they expose regions of the DNA selectively. Dynamic control of LH binding/unbinding, either globally or locally, in the presence of divalent ions, might constitute a mechanism for regulation of gene expression. PMID:22790986

The experimental study of genetic engineering human neural stem cells mediated by lentivirus to express multigene.

PubMed

Cai, Pei-qiang; Tang, Xun; Lin, Yue-qiu; Martin, Oudega; Sun, Guang-yun; Xu, Lin; Yang, Yun-kang; Zhou, Tian-hua

2006-02-01

To explore the feasibility to construct genetic engineering human neural stem cells (hNSCs) mediated by lentivirus to express multigene in order to provide a graft source for further studies of spinal cord injury (SCI). Human neural stem cells from the brain cortex of human abortus were isolated and cultured, then gene was modified by lentivirus to express both green fluorescence protein (GFP) and rat neurotrophin-3 (NT-3); the transgenic expression was detected by the methods of fluorescence microscope, dorsal root ganglion of fetal rats and slot blot. Genetic engineering hNSCs were successfully constructed. All of the genetic engineering hNSCs which expressed bright green fluorescence were observed under the fluorescence microscope. The conditioned medium of transgenic hNSCs could induce neurite flourishing outgrowth from dorsal root ganglion (DRG). The genetic engineering hNSCs expressed high level NT-3 which could be detected by using slot blot. Genetic engineering hNSCs mediated by lentivirus can be constructed to express multigene successfully.

Genetically engineered nanocarriers for drug delivery.

PubMed

Shi, Pu; Gustafson, Joshua A; MacKay, J Andrew

2014-01-01

Cytotoxicity, low water solubility, rapid clearance from circulation, and off-target side-effects are common drawbacks of conventional small-molecule drugs. To overcome these shortcomings, many multifunctional nanocarriers have been proposed to enhance drug delivery. In concept, multifunctional nanoparticles might carry multiple agents, control release rate, biodegrade, and utilize target-mediated drug delivery; however, the design of these particles presents many challenges at the stage of pharmaceutical development. An emerging solution to improve control over these particles is to turn to genetic engineering. Genetically engineered nanocarriers are precisely controlled in size and structure and can provide specific control over sites for chemical attachment of drugs. Genetically engineered drug carriers that assemble nanostructures including nanoparticles and nanofibers can be polymeric or non-polymeric. This review summarizes the recent development of applications in drug and gene delivery utilizing nanostructures of polymeric genetically engineered drug carriers such as elastin-like polypeptides, silk-like polypeptides, and silk-elastin-like protein polymers, and non-polymeric genetically engineered drug carriers such as vault proteins and viral proteins.

Genetically engineered nanocarriers for drug delivery

PubMed Central

Shi, Pu; Gustafson, Joshua A; MacKay, J Andrew

2014-01-01

Cytotoxicity, low water solubility, rapid clearance from circulation, and off-target side-effects are common drawbacks of conventional small-molecule drugs. To overcome these shortcomings, many multifunctional nanocarriers have been proposed to enhance drug delivery. In concept, multifunctional nanoparticles might carry multiple agents, control release rate, biodegrade, and utilize target-mediated drug delivery; however, the design of these particles presents many challenges at the stage of pharmaceutical development. An emerging solution to improve control over these particles is to turn to genetic engineering. Genetically engineered nanocarriers are precisely controlled in size and structure and can provide specific control over sites for chemical attachment of drugs. Genetically engineered drug carriers that assemble nanostructures including nanoparticles and nanofibers can be polymeric or non-polymeric. This review summarizes the recent development of applications in drug and gene delivery utilizing nanostructures of polymeric genetically engineered drug carriers such as elastin-like polypeptides, silk-like polypeptides, and silk-elastin-like protein polymers, and non-polymeric genetically engineered drug carriers such as vault proteins and viral proteins. PMID:24741309

DEVELOPMENT AND CHARACTERIZATION OF AN ANNULAR DENUDER METHODOLOGY FOR THE MEASUREMENT OF DIVALENT INORGANIC REACTIVE GASEOUS MERCURY IN AMBIENT AIR

EPA Science Inventory

Atmospheric mercury is predominantly present in the gaseous elemental form (Hg0). However, anthropogenic emissions (e.g. incineration, fossil fuel combustion) emit and natural processes create particulate-phase mercury (Hg(p)) and divalent reactive gas-phase mercury (RGM). RG...

IRON UPTAKE AND NRAMP-2/DMTI/DCT IN HUMAN BRONCHIAL EPITHELIAL CELLS

EPA Science Inventory

The capacity of natural resistance-associated macrophage protein-2 [Nramp2; also called divalent metal transporter-1 (DMT1) and divalent cation transporter-1 (DCT1)] to transport iron and its ubiquitous expression make it a likely candidate for transferrin-independent uptake of i...

Geochemical evidence of present-day serpentinization

USGS Publications Warehouse

Barnes, I.; LaMarche, Valmore C.; Himmelberg, G.

1967-01-01

Ultrabasic (pH > 11) water issues from some fresh ultramafic bodies. The properties of the ultrabasic solutions are believed to be due to current reactions yielding serpentine from primary olivines and pyroxenes. The low concentrations of divalent iron, divalent magnesium, and dissolved silica from the serpentinization require an increase in rock volume.

Geochemical evidence of present-day serpentinization.

PubMed

Barnes, I; Lamarche, V C; Himmelberg, G

1967-05-12

Ultrabasic (pH > 11) water issues from some fresh ultramafic bodies. The properties of the ultrabasic solutions are believed to be due to current reactions yielding serpentine from primary olivines and pyroxenes. The low concentrations of divalent airon. divalent magnesium, and dissolved silica from the serpentinization require an increase in rock volume.

A FIELD STUDY WITH GENETICALLY ENGINEERED ALFALFA INOCULATED WITH RECOMBINANT SINORHIZOBIUM MELILOTI: EFFECTS ON THE SOIL ECOSYSTEM

EPA Science Inventory

The agricultural use of genetically engineered plants and microorganisms has become increasingly common. Because genetically engineered plants and microorganisms can produce compounds foreign to their environment, there is concern that they may become established outside of thei...

What's in a name: the Vermont Genetically Engineered Food Labeling Act

PubMed Central

McPherson, Malia J.

2014-01-01

On May 8, 2014, Vermont passed the Vermont Genetically Engineered Food Labeling Act (Act) requiring labels on certain genetically engineered foods. Once the bill takes effect July 1, 2016, all Vermont-retailed foods with more than 0.9% of their total weight in genetically modified ingredients must be labeled with language stating, “may be partially produced with genetic engineering.” As genetically engineered food are considered scientifically equivalent to their traditional counterparts and are not subject to federal labeling by the FDA, the Act presents several legal questions. Several of the legal questions have been raised in a recent lawsuit filed by the Grocery Manufactures Association that claims the Act violates the First Amendment, Supremacy Clause, and Commerce Clause. This paper will discuss why the Second Circuit could strike down the Act as unconstitutional as to each claim. PMID:27774175

76 FR 44891 - Monsanto Co.; Availability of Petition, Plant Pest Risk Assessment, and Environmental Assessment...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-27

... Determination of Nonregulated Status for Corn Genetically Engineered for Drought Tolerance AGENCY: Animal and... nonregulated status for corn designated as MON 87460, which has been genetically engineered for drought... nonregulated status for corn designated as MON 87460, which has been genetically engineered for drought...

78 FR 66892 - BASF Plant Science LP; Availability of Plant Pest Risk Assessment and Environmental Assessment...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-07

... Determination of Nonregulated Status of Soybean Genetically Engineered for Herbicide Resistance AGENCY: Animal... genetically engineered for resistance to herbicides in the imidazolinone family. We are soliciting comments on... genetically engineered for resistance to herbicides in the imidazolinone family. The petition states that this...

76 FR 5780 - Determination of Regulated Status of Alfalfa Genetically Engineered for Tolerance to the...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-02

...] Determination of Regulated Status of Alfalfa Genetically Engineered for Tolerance to the Herbicide Glyphosate... for tolerance to the herbicide glyphosate based on APHIS' final environmental impact statement. FOR... regulated status of alfalfa genetically engineered for tolerance to the herbicide glyphosate based on an...

Genetic Engineering of Plants. Agricultural Research Opportunities and Policy Concerns.

ERIC Educational Resources Information Center

Roberts, Leslie

Plant scientists and science policymakers from government, private companies, and universities met at a convocation on the genetic engineering of plants. During the convocation, researchers described some of the ways genetic engineering may be used to address agricultural problems. Policymakers delineated and debated changes in research funding…

76 FR 37771 - Monsanto Co.; Availability of Petition, Plant Pest Risk Assessment, and Environmental Assessment...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-28

... Determination of Nonregulated Status for Soybean Genetically Engineered To Have a Modified Fatty Acid Profile... soybean designated as MON 87705, which has been genetically engineered to have a modified fatty acid... our regulations concerning the introduction of certain genetically engineered organisms and products...

Non-genetic engineering of cells for drug delivery and cell-based therapy.

PubMed

Wang, Qun; Cheng, Hao; Peng, Haisheng; Zhou, Hao; Li, Peter Y; Langer, Robert

2015-08-30

Cell-based therapy is a promising modality to address many unmet medical needs. In addition to genetic engineering, material-based, biochemical, and physical science-based approaches have emerged as novel approaches to modify cells. Non-genetic engineering of cells has been applied in delivering therapeutics to tissues, homing of cells to the bone marrow or inflammatory tissues, cancer imaging, immunotherapy, and remotely controlling cellular functions. This new strategy has unique advantages in disease therapy and is complementary to existing gene-based cell engineering approaches. A better understanding of cellular systems and different engineering methods will allow us to better exploit engineered cells in biomedicine. Here, we review non-genetic cell engineering techniques and applications of engineered cells, discuss the pros and cons of different methods, and provide our perspectives on future research directions. Copyright © 2014 Elsevier B.V. All rights reserved.

Genetically Modified Food: Knowledge and Attitude of Teachers and Students

NASA Astrophysics Data System (ADS)

Mohapatra, Animesh K.; Priyadarshini, Deepika; Biswas, Antara

2010-10-01

The concepts behind the technology of genetic modification of organisms and its applications are complex. A diverse range of opinions, public concern and considerable media interest accompanies the subject. This study explores the knowledge and attitudes of science teachers and senior secondary biology students about the application of a rapidly expanding technology, genetic engineering, to food production. The results indicated significant difference in understanding of concepts related with genetically engineered food stuffs between teachers and students. The most common ideas about genetically modified food were that cross bred plants and genetically modified plants are not same, GM organisms are produced by inserting a foreign gene into a plant or animal and are high yielding. More teachers thought that genetically engineered food stuffs were unsafe for the environment. Both teachers and students showed number of misconceptions, for example, the pesticidal proteins produced by GM organisms have indirect effects through bioaccumulation, induces production of allergic proteins, genetic engineering is production of new genes, GM plants are leaky sieves and that transgenes are more likely to introgress into wild species than mutated species. In general, more students saw benefits while teachers were cautious about the advantages of genetically engineered food stuffs.

Synthetic laser medium

DOEpatents

Stokowski, S.E.

1987-10-20

A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chromium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

Synthetic laser medium

DOEpatents

Stokowski, Stanley E.

1989-01-01

A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chormium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

Structural insights into the osteopontin-aptamer complex y molecular dynamics simulations

NASA Astrophysics Data System (ADS)

La Penna, Giovanni; Chelli, Riccardo

2018-01-01

Osteopontin is an intrinsically disordered protein involved in tissue remodeling. As a biomarker for pathological hypertrophy and fibrosis, the protein is targeted by an RNA aptamer. In this work, we model the interactions between osteopontin and its aptamer, including mono- (Na+) and divalent (Mg2+) cations. The molecular dynamics simulations suggest that the presence of divalent cations forces the N-terminus of osteopontin to bind the shell of divalent cations adsorbed over the surface of its RNA aptamer, the latter exposing a high negative charge density. The osteopontin plasticity as a function of the local concentration of Mg is discussed in the frame of the proposed strategies for osteopontin targeting as biomarker and in theranostic.

DIVALENT METAL TRANSPORTER-1 REGULATION BY IRON AND VANADIUM MODULATES HYDROGEN PEROXIDE-INDUCED DNA DAMAGE IN LUNG CELLS

EPA Science Inventory

The divalent metal transporter-1 (DMT1) participates in the detoxification of metals that can damage lung epithelium. Elevated iron levels increase the expression of DMT1 in bronchial epithelial cells stimulating its uptake and storage in ferritin, thus making iron unavailable t...

Murine genetically engineered and human xenograft models of chronic lymphocytic leukemia.

PubMed

Chen, Shih-Shih; Chiorazzi, Nicholas

2014-07-01

Chronic lymphocytic leukemia (CLL) is a genetically complex disease, with multiple factors having an impact on onset, progression, and response to therapy. Genetic differences/abnormalities have been found in hematopoietic stem cells from patients, as well as in B lymphocytes of individuals with monoclonal B-cell lymphocytosis who may develop the disease. Furthermore, after the onset of CLL, additional genetic alterations occur over time, often causing disease worsening and altering patient outcomes. Therefore, being able to genetically engineer mouse models that mimic CLL or at least certain aspects of the disease will help us understand disease mechanisms and improve treatments. This notwithstanding, because neither the genetic aberrations responsible for leukemogenesis and progression nor the promoting factors that support these are likely identical in character or influences for all patients, genetically engineered mouse models will only completely mimic CLL when all of these factors are precisely defined. In addition, multiple genetically engineered models may be required because of the heterogeneity in susceptibility genes among patients that can have an effect on genetic and environmental characteristics influencing disease development and outcome. For these reasons, we review the major murine genetically engineered and human xenograft models in use at the present time, aiming to report the advantages and disadvantages of each. Copyright © 2014 Elsevier Inc. All rights reserved.

U.S. Adults with Agricultural Experience Report More Genetic Engineering Familiarity than Those Without

ERIC Educational Resources Information Center

Stofer, Kathryn A.; Schiebel, Tracee M.

2017-01-01

Researchers and pollsters still debate the acceptance of genetic engineering technology among U.S. adults, and continue to assess their knowledge as part of this research. While decision-making may not rely entirely on knowledge, querying opinions and perceptions rely on public understanding of genetic engineering terms. Experience with…

Can Man Control His Biological Evolution? A Symposium on Genetic Engineering. Genetic Engineering

ERIC Educational Resources Information Center

Ramsey, Paul

1972-01-01

Presented are issues related to genetic engineering. Increased knowledge of techniques to manipulate genes are apt to create confusion about moral values in relation to unborn babies and other living organisms on earth. Human beings may use this knowledge to disturb the balance maintained by nature. (PS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Chunya; Skelton, Adam A.; Chen, Mingjun

Here the binding of a negatively charged residue, aspartic acid (Asp) in tripeptide arginine-glycine-aspartic acid, onto a negatively charged hydroxylated rutile (110) surface in aqueous solution, containing divalent (Mg 2+, Ca 2+, or Sr 2+) or monovalent (Na +, K +, or Rb +) cations, was studied by molecular dynamics (MD) simulations. The results indicate that ionic radii and charges will significantly affect the hydration, adsorption geometry, and distance of cations from the rutile surface, thereby regulating the Asp/rutile binding mode. The adsorption strength of monovalent cations on the rutile surface in the order Na + > K + >more » Rb + shows a “reverse” lyotropic trend, while the divalent cations on the same surface exhibit a “regular” lyotropic behavior with decreasing crystallographic radii (the adsorption strength of divalent cations: Sr 2+ > Ca 2+ > Mg 2+). The Asp side chain in NaCl, KCl, and RbCl solutions remains stably H-bonded to the surface hydroxyls and the inner-sphere adsorbed compensating monovalent cations act as a bridge between the COO – group and the rutile, helping to “trap” the negatively charged Asp side chain on the negatively charged surface. In contrast, the mediating divalent cations actively participate in linking the COO– group to the rutile surface; thus the Asp side chain can remain stably on the rutile (110) surface, even if it is not involved in any hydrogen bonds with the surface hydroxyls. Inner- and outer-sphere geometries are all possible mediation modes for divalent cations in bridging the peptide to the rutile surface.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Starcher, Autumn N.; Elzinga, Evert J.; Sparks, Donald L.

Previous research demonstrated the formation of single divalent metal (Co, Ni, and ZnAl) and mixed divalent metal (NiZnAl) layered double hydroxide (LDH) phases from reactions of the divalent metal with Al-bearing substrates and soils in both laboratory experiments and in the natural environment. Recently Fe(II)-Al-LDH phases have been found in laboratory batch reaction studies, and although they have yet to be found in the natural environment. Potential locations of Fe(II)-Al-LDH phases in nature include areas with suboxic and anoxic conditions. Because these areas can be environments of significant contaminant accumulation, it is important to understand the possible interactions and impactsmore » of contaminant elements on LDH phase formation. One such contaminant, Zn, can also form as an LDH and has been found to form as a mixed divalent layered hydroxide phase. To understand how Zn impacts the formation of Fe(II)-Al-LDH phase formation and kinetics, 3 mM or 0.8 mM Fe(II) and 0.8 mM Zn were batch reacted with either 10 g/L pyrophyllite or 7.5 g/L γ-Al2O3 for up to three months under anoxic conditions. Aqueous samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) and solid samples were analyzed with X-ray absorption spectroscopy (XAS). Shell-by-shell fits of Fe(II) and co-sorption samples with pyrophyllite show the formation of a mixed divalent metal (Fe(II)-Zn-Al) layered hydroxide phase, while Fe(II) and Zn co-sorption samples with γ-Al2O3 produce Fe(II)-Al-LDH phases and Zn in inner-sphere complexation with the γ-Al2O3. This study demonstrates the formation of a mixed divalent metal layered hydroxide and further iterates the importance of sorbent reactivity on LDH phase formation.« less

Genetic Engineering of Alfalfa (Medicago sativa L.).

PubMed

Wang, Dan; Khurshid, Muhammad; Sun, Zhan Min; Tang, Yi Xiong; Zhou, Mei Liang; Wu, Yan Min

2016-01-01

Alfalfa is excellent perennial legume forage for its extensive ecological adaptability, high nutrition value, palatability and biological nitrogen fixation. It plays a very important role in the agriculture, animal husbandry and ecological construction. It is cultivated in all continents. With the development of modern plant breeding and genetic engineering techniques, a large amount of work has been carried out on alfalfa. Here we summarize the recent research advances in genetic engineering of alfalfa breeding, including transformation, quality improvement, stress resistance and as a bioreactor. The review article can enables us to understand the research method, direction and achievements of genetic engineering technology of Alfalfa.

Moral Fantasy in Genetic Engineering.

ERIC Educational Resources Information Center

Boone, C. Keith

1984-01-01

Discusses the main ethical issues generated by the new genetics and suggests ways to think about them. Concerns include "playing God," violation of the natural order of the universe, and abuse of genetic technology. Critical distinctions for making difficult decisions about genetic engineering issues are noted. (DH)

Genetic Engineering Strategies for Enhanced Biodiesel Production.

PubMed

Hegde, Krishnamoorthy; Chandra, Niharika; Sarma, Saurabh Jyoti; Brar, Satinder Kaur; Veeranki, Venkata Dasu

2015-07-01

The focus on biodiesel research has shown a tremendous growth over the last few years. Several microbial and plant sources are being explored for the sustainable biodiesel production to replace the petroleum diesel. Conventional methods of biodiesel production have several limitations related to yield and quality, which led to development of new engineering strategies to improve the biodiesel production in plants, and microorganisms. Substantial progress in utilizing algae, yeast, and Escherichia coli for the renewable production of biodiesel feedstock via genetic engineering of fatty acid metabolic pathways has been reported in the past few years. However, in most of the cases, the successful commercialization of such engineering strategies for sustainable biodiesel production is yet to be seen. This paper systematically presents the drawbacks in the conventional methods for biodiesel production and an exhaustive review on the present status of research in genetic engineering strategies for production of biodiesel in plants, and microorganisms. Further, we summarize the technical challenges need to be tackled to make genetic engineering technology economically sustainable. Finally, the need and prospects of genetic engineering technology for the sustainable biodiesel production and the recommendations for the future research are discussed.

77 FR 41350 - Monsanto Co.; Determination of Nonregulated Status of Soybean Genetically Engineered To Produce...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... MON 87769, which has been genetically engineered to produce stearidonic acid, an omega-3 fatty acid... 87769, which has been genetically engineered to produce stearidonic acid, an omega-3 fatty acid not... NEPA (40 CFR parts 1500-1508), (3) USDA regulations implementing NEPA (7 CFR part 1b), and (4) APHIS...

A field release of genetically engineered gypsy moth (Lymantria dispar L.) Nuclear Polyhedrosis Virus (LdNPV)

Treesearch

Vincent D' Amico; Joseph S. Elkinton; John D. Podgwaite; James M. Slavicek; Michael L. McManus; John P. Burand

1999-01-01

The gypsy moth (Lymantria dispar L.) nuclear polyhedrosis virus was genetically engineered for nonpersistence by removal of the gene coding for polyhedrin production and stabilized using a coocclusion process. A β-galactosidase marker gene was inserted into the genetically engineered virus (LdGEV) so that infected larvae could be tested for...

78 FR 13303 - Stine Seed Farm, Inc.; Availability of Plant Pest Risk Assessment, Environmental Assessment, and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-27

... reason to believe are plant pests. Such genetically engineered organisms (GE) and products are considered... genetically engineered organisms. Paragraph (e) of Sec. 340.6 provides that APHIS will publish a notice in the... Preliminary Decision for an Extension of a Determination of Nonregulated Status of Corn Genetically Engineered...

PRECIPITATION OF PROTACTINIUM

DOEpatents

Moore, R.L.

1958-07-15

An lmprovement in the separation of protactinium from aqueous nitric acid solutions is described. 1t covers the use of lead dioxide and tin dioxide as carrier precipitates for the protactinium. In carrying out the process, divalent lead or divalent tin is addcd to the solution and oxidized, causing formation of a carrier precipitate of lead dioxide or stannic oxide, respectively.

DIVALENT INORGANIC REACTIVE GASEOUS MERCURY EMISSIONS FROM A MERCURY CELL CHLOR-ALKALI PLANT AND ITS IMPACT ON NEAR FIELD ATMOSPHERIC DRY DEPOSITION

EPA Science Inventory

The emission of inorganic divalent reactive gaseous mercury (RGM) from a mercury cell chlor-alkali plant (MCCAP) cell building and the impact on near field (100 km) dry deposition was investigated as part of a larger collaborative study between EPA, University of Michigan, Oak ...

Human Genetic Engineering: A Survey of Student Value Stances

ERIC Educational Resources Information Center

Wilson, Sara McCormack; And Others

1975-01-01

Assesses the values of high school and college students relative to human genetic engineering and recommends that biology educators explore instructional strategies merging human genetic information with value clarification techniques. (LS)

Some engineering aspects of homoionized mixed clay minerals.

PubMed

Oren, Ali Hakan; Kaya, Abidin

2003-05-01

Many studies have been conducted to investigate the physicochemical behavior of pure clay minerals and predict their engineering performance in the field. In this study, the physicochemical properties of an artificial mixture of different clay minerals namely, 40-50% montmorillonite, 20-30% illite and 10-15% kaolin were investigated. The mixture was homoionized with sodium, Na+; calcium, Ca2+; and aluminum, Al3+. The engineering properties studied were consistency limits, sediment volume, compressibility behavior, and hydraulic conductivity. The results revealed that the liquid, plastic and shrinkage limits of soil increased with increasing cation valence. The hydraulic conductivity of the soil also increased with an increase in the valence of the cation at any given void ratio. Aluminum and sodium treated clays had the highest and the lowest modified compression index values, respectively. Furthermore, trivalent cation saturated clayey soil consolidates three times faster than that of monovalent and two times faster than that of divalent. These properties of the soils determined were, in general, similar to those of kaolinite rather than those of montmorillonite. The comparison of the results obtained with the published data in the literature revealed that the physicochemical behavior of the tested clay soil was, in general, similar to that of kaolinite.

Genetic Engineering Workshop Report, 2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen, J; Slezak, T

2010-11-03

The Lawrence Livermore National Laboratory (LLNL) Bioinformatics group has recently taken on a role in DTRA's Transformation Medical Technologies (TMT) program. The high-level goal of TMT is to accelerate the development of broad-spectrum countermeasures. To achieve this goal, there is a need to assess the genetic engineering (GE) approaches, potential application as well as detection and mitigation strategies. LLNL was tasked to coordinate a workshop to determine the scope of investments that DTRA should make to stay current with the rapid advances in genetic engineering technologies, so that accidental or malicious uses of GE technologies could be adequately detected andmore » characterized. Attachment A is an earlier report produced by LLNL for TMT that provides some relevant background on Genetic Engineering detection. A workshop was held on September 23-24, 2010 in Springfield, Virginia. It was attended by a total of 55 people (see Attachment B). Twenty four (44%) of the attendees were academic researchers involved in GE or bioinformatics technology, 6 (11%) were from DTRA or the TMT program management, 7 (13%) were current TMT performers (including Jonathan Allen and Tom Slezak of LLNL who hosted the workshop), 11 (20%) were from other Federal agencies, and 7 (13%) were from industries that are involved in genetic engineering. Several attendees could be placed in multiple categories. There were 26 attendees (47%) who were from out of the DC area and received travel assistance through Invitational Travel Orders (ITOs). We note that this workshop could not have been as successful without the ability to invite experts from outside of the Beltway region. This workshop was an unclassified discussion of the science behind current genetic engineering capabilities. US citizenship was not required for attendance. While this may have limited some discussions concerning risk, we felt that it was more important for this first workshop to focus on the scientific state of the art. We also consciously chose to not dwell on matters of policy (for example, screening of commercial gene or oligo synthesis orders), as multiple other forums for policy discussion have taken place in recent years. We acknowledge that other workshops on topics relevant to genetic engineering should be held, some of which may need to take place at higher classification levels. The workshop moderators would like to acknowledge the enthusiastic participation of the attendees in the discussions. Special thanks are given to Sofi Ibrahim, for his extensive assistance on helping this report reach its final form. The genetic engineering workshop brought together a diverse mix of genetic engineering pioneers and experts, Federal agency representatives concerned with abuses of genetic engineering, TMT performers, bioinformatics experts, and representatives from industry involved with large-scale genetic engineering and synthetic biology. Several talks established the current range of genetic engineering capabilities and the relative difficulties of identifying and characterizing the results of their use. Extensive discussions established a number of recommendations to DTRA of how to direct future research investments so that any mis-use of genetic engineering techniques can be promptly identified and characterized.« less

Synthesis and characterization of time-resolved fluorescence probes for evaluation of competitive binding to melanocortin receptors.

PubMed

Alleti, Ramesh; Vagner, Josef; Dehigaspitiya, Dilani Chathurika; Moberg, Valerie E; Elshan, N G R D; Tafreshi, Narges K; Brabez, Nabila; Weber, Craig S; Lynch, Ronald M; Hruby, Victor J; Gillies, Robert J; Morse, David L; Mash, Eugene A

2013-09-01

Probes for use in time-resolved fluorescence competitive binding assays at melanocortin receptors based on the parental ligands MSH(4), MSH(7), and NDP-α-MSH were prepared by solid phase synthesis methods, purified, and characterized. The saturation binding of these probes was studied using HEK-293 cells engineered to overexpress the human melanocortin 4 receptor (hMC4R) as well as the human cholecystokinin 2 receptor (hCCK2R). The ratios of non-specific binding to total binding approached unity at high concentrations for each probe. At low probe concentrations, receptor-mediated binding and uptake was discernable, and so probe concentrations were kept as low as possible in determining Kd values. The Eu-DTPA-PEGO-MSH(4) probe exhibited low specific binding relative to non-specific binding, even at low nanomolar concentrations, and was deemed unsuitable for use in competition binding assays. The Eu-DTPA-PEGO probes based on MSH(7) and NDP-α-MSH exhibited Kd values of 27±3.9nM and 4.2±0.48nM, respectively, for binding with hMC4R. These probes were employed in competitive binding assays to characterize the interactions of hMC4R with monovalent and divalent MSH(4), MSH(7), and NDP-α-MSH constructs derived from squalene. Results from assays with both probes reflected only statistical enhancements, suggesting improper ligand spacing on the squalene scaffold for the divalent constructs. The Ki values from competitive binding assays that employed the MSH(7)-based probe were generally lower than the Ki values obtained when the probe based on NDP-α-MSH was employed, which is consistent with the greater potency of the latter probe. The probe based on MSH(7) was also competed with monovalent, divalent, and trivalent MSH(4) constructs that previously demonstrated multivalent binding in competitive binding assays against a variant of the probe based on NDP-α-MSH. Results from these assays confirm multivalent binding, but suggest a more modest increase in avidity for these MSH(4) constructs than was previously reported. Copyright © 2013 Elsevier Ltd. All rights reserved.

Genetic Engineering: A Matter that Requires Further Refinement in Spanish Secondary School Textbooks

ERIC Educational Resources Information Center

Martinez-Gracia, M. V.; Gil-Quylez, M. J.; Osada, J.

2003-01-01

Genetic engineering is now an integral part of many high school textbooks but little work has been done to assess whether it is being properly addressed. A checklist with 19 items was used to analyze how genetic engineering is presented in biology textbooks commonly used in Spanish high schools, including the content, its relationship with…

Genetically engineered orange petunias on the market.

PubMed

Bashandy, Hany; Teeri, Teemu H

2017-08-01

Unauthorized genetically engineered orange petunias were found on the market. Genetic engineering of petunia was shown to lead to novel flower color some 20 years ago. Here we show that petunia lines with orange flowers, generated for scientific purposes, apparently found their way to petunia breeding programmes, intentionally or unintentionally. Today they are widely available, but have not been registered for commerce.

The Effect of Case Teaching on Meaningful and Retentive Learning When Studying Genetic Engineering

ERIC Educational Resources Information Center

Güccük, Ahmet; Köksal, Mustafa Serdar

2017-01-01

The purpose of this study is to investigate the effects of case teaching on how students learn about genetic engineering, in terms of meaningful learning and retention of learning. The study was designed as quasi-experimental research including 63 8th graders (28 boys and 35 girls). To collect data, genetic engineering achievement tests were…

German politics of genetic engineering and its deconstruction.

PubMed

Gottweis, H

1995-05-01

Policy-making, as exemplified by biotechnology policy, can be understood as an attempt to manage a field of discursivity, to construct regularity in a dispersed multitude of combinable elements. Following this perspective of politics as a textual process, the paper interprets the politicization of genetic engineering in Germany as a defence of the political as a regime of heterogeneity, as a field of 'dissensus' rather than 'consensus', and a rejection of the idea that the framing of technological transformation is an autonomous process. From its beginning in the early 1970s, genetic engineering was symbolically entrenched as a key technology of the future, and as an integral element of the German politics of modernization. Attempts by new social movements and the Green Party to displace the egalitarian imaginary of democratic discourse into the politics of genetic engineering were construed by the political élites as an attack on the political order of post-World War II Germany. The 1990 Genetic Engineering Law attempted a closure of this controversy. But it is precisely the homogenizing idiom of this 'settlement' which continues to nourish the social movements and their radical challenge to the definitions and codings of the politics of genetic engineering.

The use of genetically-engineered animals in science: perspectives of Canadian Animal Care Committee members.

PubMed

Ormandy, Elisabeth H; Dale, Julie; Griffin, Gilly

2013-05-01

The genetic engineering of animals for their use in science challenges the implementation of refinement and reduction in several areas, including the invasiveness of the procedures involved, unanticipated welfare concerns, and the numbers of animals required. Additionally, the creation of genetically-engineered animals raises problems with the Canadian system of reporting animal numbers per Category of Invasiveness, as well as raising issues of whether ethical limits can, or should, be placed on genetic engineering. A workshop was held with the aim of bringing together Canadian animal care committee members to discuss these issues, to reflect on progress that has been made in addressing them, and to propose ways of overcoming any challenges. Although previous literature has made recommendations with regard to refinement and reduction when creating new genetically-engineered animals, the perception of the workshop participants was that some key opportunities are being missed. The participants identified the main roadblocks to the implementation of refinement and reduction alternatives as confidentiality, cost and competition. If the scientific community is to make progress concerning the implementation of refinement and reduction, particularly in the creation and use of genetically-engineered animals, addressing these roadblocks needs to be a priority. 2013 FRAME.

Genetic engineering including superseding microinjection: new ways to make GM pigs.

PubMed

Galli, Cesare; Perota, Andrea; Brunetti, Dario; Lagutina, Irina; Lazzari, Giovanna; Lucchini, Franco

2010-01-01

Techniques for genetic engineering of swine are providing genetically modified animals of importance for the field of xenotransplantation, animal models for human diseases and for a variety of research applications. Many of these modifications have been directed toward avoiding naturally existing cellular and antibody responses to species-specific antigens. A number of techniques are today available to engineering the genome of mammals, these range from the well established less efficient method of DNA microinjection into the zygote, the use of viral vectors, to the more recent use of somatic cell nuclear transfer. The use of enzymatic engineering that are being developed now will refine the precision of the genetic modification combined with the use of new vectors like transposons. The use of somatic cell nuclear transfer is currently the most efficient way to generate genetically modified pigs. The development of enzymatic engineering with zinc-finger nucleases, recombinases and transposons will revolutionize the field. Nevertheless, genetic engineering in large domesticated animals will remain a challenging task. Recent improvements in several fields of cell and molecular biology offer new promises and opportunities toward an easier, cost-effective and efficient generation of transgenic pigs. © 2010 John Wiley & Sons A/S.

Genetically Engineered Cyanobacteria

NASA Technical Reports Server (NTRS)

Zhou, Ruanbao (Inventor); Gibbons, William (Inventor)

2015-01-01

The disclosed embodiments provide cyanobacteria spp. that have been genetically engineered to have increased production of carbon-based products of interest. These genetically engineered hosts efficiently convert carbon dioxide and light into carbon-based products of interest such as long chained hydrocarbons. Several constructs containing polynucleotides encoding enzymes active in the metabolic pathways of cyanobacteria are disclosed. In many instances, the cyanobacteria strains have been further genetically modified to optimize production of the carbon-based products of interest. The optimization includes both up-regulation and down-regulation of particular genes.

Genetic engineering of Ganoderma lucidum for the efficient production of ganoderic acids.

PubMed

Xu, Jun-Wei; Zhong, Jian-Jiang

2015-01-01

Ganoderma lucidum is a well-known traditional medicinal mushroom that produces ganoderic acids with numerous interesting bioactivities. Genetic engineering is an efficient approach to improve ganoderic acid biosynthesis. However, reliable genetic transformation methods and appropriate genetic manipulation strategies remain underdeveloped and thus should be enhanced. We previously established a homologous genetic transformation method for G. lucidum; we also applied the established method to perform the deregulated overexpression of a homologous 3-hydroxy-3-methyl-glutaryl coenzyme A reductase gene in G. lucidum. Engineered strains accumulated more ganoderic acids than wild-type strains. In this report, the genetic transformation systems of G. lucidum are described; current trends are also presented to improve ganoderic acid production through the genetic manipulation of G. lucidum.

Condensation of monovalent and divalent metal ions on a Langmuir monolayer

NASA Astrophysics Data System (ADS)

Bloch, J. Mati; Yun, Wenbing

1990-01-01

A system that consists of a monolayer spread on a solution containing a monovalent and a divalent ion is investigated. The solution of the Poisson-Boltzmann-Stern equation for this system indicates that the metal ions segregating to the surface can be found in two distinct states. Divalent ions are chemically condensed on the monolayer, while monovalent ions are electrically attracted to it. We derive simple expressions for the charge left on the surfactant monolayer and the amount of metal ions condensed on the monolayer. These formulas reproduce very accurately (to within pro milles) the values obtained using the nonlinear Grahame equation and eliminate the need to solve that equation. That permits a simple identification of the state of the surfactant monolayer and we propose a universal condensation chart that characterizes the state of the surfactant. We further derive a chemical equilibrium equation for the surface components that has considerable range of validity. This equation requires a knowledge of the bulk concentrations only, and thus allows in many cases the identification of the state of the monolayer, avoiding the need to solve the full nonlinear Poisson-Boltzmann equation. All existing experimental results on Langmuir systems are in good agreement with the one-dimensional Poisson-Boltzmann-Stern model with no adjustable parameters. Several of these fits are presented in this work and are also mapped on the condensation chart. Our calculations point to some characteristic differences between the monovalent and the divalent ions that explain why it is possible to build Langmuir-Blodgett multilayers from divalent compensated surfactants but not from monovalent ones.

Strontium, barium, and manganese metabolism in isolated presynaptic nerve terminals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rasgado-Flores, H.; Sanchez-Armass, S.; Blaustein, M.P.

1987-06-01

To gain insight into the mechanisms by which the divalent cations Sr, Ba, and Mn affect neurotransmitter release from presynaptic nerve terminals, the authors examined the sequestration of these cations, ion comparison to Ca, by mitochondrial and nonmitochondrial organelles and the extrusion of these cations from isolated nerve terminals. Sequestration was studied in synaptosomes made leaky to small ions by treatment with saponin; efflux was examined in intact synaptosomes that were preloaded with the divalent cations by incubation in depolarizing (K rich) media. The selectivity sequence for ATP-dependent mitochondrial uptake that they observed was Mn>>Ca>Sr>>Ba, whereas that for the SERmore » was Ca greater than or equal to Mn>Sr>>Ba. When synaptosomes that were preloaded with divalent cations were incubated in Na- and Ca-free media, there was little efflux of /sup 45/Ca, /sup 133/Ba, /sup 85/Sr, or /sup 54/Mn. When the incubation was carried out in media containing Na without Ca, there was substantial stimulation of Ca and Sr efflux, but only slight stimulation of Ba or Mn efflux. In Na-free media, the addition of 1 mM Ca promoted the efflux of all four divalent cations, probably via Ca-divalent cation exchange. In summary, the sequestration and extrusion data suggest that, with equal loads, Mn will be buffered to the greatest extent, whereas Ba will be least well buffered. These results may help to explain why Mn has a very long-lasting effect on transmitter release, while the effect of Sr is much briefer.« less

Heme Regulates Allosteric Activation of the Slo1 BK Channel

PubMed Central

Horrigan, Frank T.; Heinemann, Stefan H.; Hoshi, Toshinori

2005-01-01

Large conductance calcium-dependent (Slo1 BK) channels are allosterically activated by membrane depolarization and divalent cations, and possess a rich modulatory repertoire. Recently, intracellular heme has been identified as a potent regulator of Slo1 BK channels (Tang, X.D., R. Xu, M.F. Reynolds, M.L. Garcia, S.H. Heinemann, and T. Hoshi. 2003. Nature. 425:531–535). Here we investigated the mechanism of the regulatory action of heme on heterologously expressed Slo1 BK channels by separating the influences of voltage and divalent cations. In the absence of divalent cations, heme generally decreased ionic currents by shifting the channel's G–V curve toward more depolarized voltages and by rendering the curve less steep. In contrast, gating currents remained largely unaffected by heme. Simulations suggest that a decrease in the strength of allosteric coupling between the voltage sensor and the activation gate and a concomitant stabilization of the open state account for the essential features of the heme action in the absence of divalent ions. At saturating levels of divalent cations, heme remained similarly effective with its influence on the G–V simulated by weakening the coupling of both Ca2+ binding and voltage sensor activation to channel opening. The results thus show that heme dampens the influence of allosteric activators on the activation gate of the Slo1 BK channel. To account for these effects, we consider the possibility that heme binding alters the structure of the RCK gating ring and thereby disrupts both Ca2+- and voltage-dependent gating as well as intrinsic stability of the open state. PMID:15955873

Membrane Order Is a Key Regulator of Divalent Cation-Induced Clustering of PI(3,5)P2 and PI(4,5)P2.

PubMed

Sarmento, Maria J; Coutinho, Ana; Fedorov, Aleksander; Prieto, Manuel; Fernandes, Fábio

2017-10-31

Although the evidence for the presence of functionally important nanosized phosphorylated phosphoinositide (PIP)-rich domains within cellular membranes has accumulated, very limited information is available regarding the structural determinants for compartmentalization of these phospholipids. Here, we used a combination of fluorescence spectroscopy and microscopy techniques to characterize differences in divalent cation-induced clustering of PI(4,5)P 2 and PI(3,5)P 2 . Through these methodologies we were able to detect differences in divalent cation-induced clustering efficiency and cluster size. Ca 2+ -induced PI(4,5)P 2 clusters are shown to be significantly larger than the ones observed for PI(3,5)P 2 . Clustering of PI(4,5)P 2 is also detected at physiological concentrations of Mg 2+ , suggesting that in cellular membranes, these molecules are constitutively driven to clustering by the high intracellular concentration of divalent cations. Importantly, it is shown that lipid membrane order is a key factor in the regulation of clustering for both PIP isoforms, with a major impact on cluster sizes. Clustered PI(4,5)P 2 and PI(3,5)P 2 are observed to present considerably higher affinity for more ordered lipid phases than the monomeric species or than PI(4)P, possibly reflecting a more general tendency of clustered lipids for insertion into ordered domains. These results support a model for the description of the lateral organization of PIPs in cellular membranes, where both divalent cation interaction and membrane order are key modulators defining the lateral organization of these lipids.

Divalent cations in tears, and their influence on tear film stability in humans and rabbits.

PubMed

Wei, Xiaojia Eric; Markoulli, Maria; Millar, Thomas J; Willcox, Mark D P; Zhao, Zhenjun

2012-06-05

Reduced tear film stability is reported to contribute to dry eye. Rabbits are known to have a more stable tear film than humans. Thus, we sought to examine the tears of rabbits and humans for metal cations, and to test how they influence tear film stability. Tears were collected from 10 healthy humans and 6 rabbits. Tear osmolality was measured by vapor pressure osmometer, and metals analyzed using inductively coupled plasma (ICP) mass spectrometry or ICP atomic emission spectroscopy. The influence of divalent cations on tears was analyzed by measuring surface tension using the Langmuir trough in vitro, using different concentrations of cations in the subphase, and grading the tear break-up in rabbits in vivo after instillation of chelating agents. Rabbit tears had a higher osmolality compared to humans. Major metals did not differ between species; however, rabbits had higher levels of Mg(2+) (1.13 vs. 0.39 mM) and Ca(2+) (0.75 vs. 0.36 mM). In rabbit tears in vitro, diminishing divalent cations resulted in a decrease in the maximum surface pressure from 37 to 30 mN/m. In vivo, an increase in the amount of tear film that was broken-up was found. In contrast, when changing divalent cation concentrations in human tears, the maximum surface pressure remained at 26 mN/m. The normal osmolality of rabbit tears is significantly higher than that in humans. While divalent cations had little influence on human tears, they appear to have an important role in maintaining tear film stability in rabbits.

Isolation and divalent-metal activation of a ß-xylosidase, RUM630-BX

USDA-ARS?s Scientific Manuscript database

The gene encoding RUM630-BX, a ß-xylosidase/arabinofuranosidase, was identified from activity-based screening of a cow rumen metagenomic library. The recombinant enzyme is activated as much as 14-fold (kcat) by divalent metals Mg2+, Mn2+ and Co2+ but not by Ca2+, Ni2+, and Zn2+. Activation of RUM6...

Characterization of zinc transport by divalent metal transporters of the ZIP family from the model legume medicago truncatula

USDA-ARS?s Scientific Manuscript database

To understand how plants from the Fabaceae family maintain zinc (Zn) homeostasis, we have characterized the kinetics of the Zn transporting proteins from the ZIP family of divalent metal transporters in the model legume Medicago truncatula. MtZIP1, MtZIP5, and MtZIP6 were the only members from this ...

Process for removing sulfur from coal

DOEpatents

Aida, Tetsuo; Squires, Thomas G.; Venier, Clifford G.

1985-02-05

A process for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

Enhancing tonoplast Cd/H antiport activity increases Cd, Zn, and Mn tolerance, and impacts root/shoot Cd partitioning in Nicotiana tabacum L.

USDA-ARS?s Scientific Manuscript database

Sequestration mechanisms that prevent high concentrations of free metal ions from persisting in metabolically active compartments of cells are thought to be central in tolerance of plants to high levels of divalent cation metals. Expression of "AtCAX2" or "AtCAX4", which encode divalent cation/proto...

Super-high-affinity binding site for [3H]diazepam in the presence of Co2+, Ni2+, Cu2+, or Zn2+.

PubMed

Mizuno, S; Ogawa, N; Mori, A

1982-12-01

Chloride salts of Li+, Na+, K+, Mg2+, Ca2+, Cr3+, Mn2+, Fe2+, and Fe3+ had no effect on [3H]diazepam binding. Chloride salts of Co2+, Ni2+, Cu2+, and Zn2+ increased [3H]diazepam binding by 34 to 68% in a concentration-dependent fashion. Since these divalent cations potentiated the GABA-enhanced [3H]diazepam binding and the effect of each divalent cation was nearly additive with GABA, these cations probably act at a site different from the GABA recognition site in the benzodiazepine-receptor complex. Scatchard plots of [3H]diazepam binding without an effective divalent cation showed a single class of binding, with a Kd value of 5.3 nM. In the presence of 1 mM Co2+, Ni2+, Cu2+, or Zn2+, two distinct binding sites were evident with apparent Kd values of 1.0 nM and 5.7 nM. The higher-affinity binding was not detected in the absence of an effective divalent cation and is probably a novel, super-high-affinity binding site.

Dynamics of Pseudomonas aeruginosa association with anionic hydrogel surfaces in the presence of aqueous divalent-cation salts

PubMed Central

Tran, Victoria B.; Sung, Ye Suel; Fleiszig, Suzanne M.J.; Evans, David J.; Radke, C.J.

2013-01-01

Binding of bacteria to solid surfaces is complex with many aspects incompletely understood. We investigate Pseudomonas aeruginosa uptake kinetics onto hydrogel surfaces representative of soft-contact lenses made of nonionic poly(2-hydroxyethylmethacrylate) (p-HEMA), anionic poly(methacrylic acid) (p-MAA), and anionic poly(acrylic acid) (p-AA). Using a parallel-plate flow cell under phase-contrast microscopy, we document a kinetic “burst” at the anionic hydrogel surface: dilute aqueous P. aeruginosa first rapidly accumulates and then rapidly depletes. Upon continuing flow, divalent cations in the suspending solution sorb into the hydrogel network causing the previously surface-accumulated bacteria to desorb. The number of bacteria eventually bound to the surface is low compared to the nonionic p-HEMA hydrogel. We propose that the kinetic burst is due to reversible divalent-cation bridging between the anionic bacteria and the negatively charged hydrogel surface. The number of surface bridging sites diminishes as divalent cations impregnate into and collapse the gel. P. aeruginosa association with the surface then falls. Low eventual binding of P. aeruginosa to the anionic hydrogel is ascribed to increased surface hydrophilicity compared to the counterpart nonionic p-HEMA hydrogel. PMID:21723562

Lipid domains in zwitterionic-anionic lipid mixtures induced by combined effect of monovalent and divalent ions

NASA Astrophysics Data System (ADS)

Xu, Hongcheng; Ganesan, Sai; Matysiak, Silvina

Lipid domain formation is an important process for many cellular processes. In experiment, the effects of Ba2+, Sr2+, Ca2+ and Mg2+ in inducing lateral phase separation in the binary phosphatidylcholine-phosphatidylserine (PC-PS) bilayer are quite different, of which the molecular mechanism remains to be understood. We have explored the effect of monovalent (MI) and divalent (MII) cationic radii on lipid domain formation in mixed zwitterionic-anionic lipid bilayers. We propose a mechanism for the formation of divalent-cation-induced lipid domains based on MD simulations with our Water-Explicit Polarizable MEMbrane (WEPMEM) coarse-grained model, which uses PC as the model for zwitterionic and PS for anionic lipids. Lipid aggregation only occurs with limited range of monovalent and divalent ion sizes in agreement with experimental observations. More ordering and closer packing of the lipids are noted within the domains, which correlate with bilayer thickness, curvature and lipid asymmetry. The results of the simulations reveal that the lipid domain consists of MII-mediated anionic lipid dimer/trimer complexes bridged by monovalent ions MI and provide a stereochemical insight in understanding the experimentally observed calcium-induced phase separation.

Predicting 3D structure and stability of RNA pseudoknots in monovalent and divalent ion solutions.

PubMed

Shi, Ya-Zhou; Jin, Lei; Feng, Chen-Jie; Tan, Ya-Lan; Tan, Zhi-Jie

2018-06-01

RNA pseudoknots are a kind of minimal RNA tertiary structural motifs, and their three-dimensional (3D) structures and stability play essential roles in a variety of biological functions. Therefore, to predict 3D structures and stability of RNA pseudoknots is essential for understanding their functions. In the work, we employed our previously developed coarse-grained model with implicit salt to make extensive predictions and comprehensive analyses on the 3D structures and stability for RNA pseudoknots in monovalent/divalent ion solutions. The comparisons with available experimental data show that our model can successfully predict the 3D structures of RNA pseudoknots from their sequences, and can also make reliable predictions for the stability of RNA pseudoknots with different lengths and sequences over a wide range of monovalent/divalent ion concentrations. Furthermore, we made comprehensive analyses on the unfolding pathway for various RNA pseudoknots in ion solutions. Our analyses for extensive pseudokonts and the wide range of monovalent/divalent ion concentrations verify that the unfolding pathway of RNA pseudoknots is mainly dependent on the relative stability of unfolded intermediate states, and show that the unfolding pathway of RNA pseudoknots can be significantly modulated by their sequences and solution ion conditions.

Genetically Engineered Immunotherapy for Advanced Cancer

Cancer.gov

In this trial, doctors will collect T lymphocytes from patients with advanced mesothelin-expressing cancer and genetically engineer them to recognize mesothelin. The gene-engineered cells will be multiplied and infused into the patient to fight the cancer

Separations of actinides, lanthanides and other metals

DOEpatents

Smith, Barbara F.; Jarvinen, Gordon D.; Ensor, Dale D.

1995-01-01

An organic extracting solution comprised of a bis(acylpyrazolone or a substituted bis(acylpyrazolone) and an extraction method useful for separating certain elements of the actinide series of the periodic table having a valence of four from one other, and also from one or more of the substances in a group consisting of hexavalent actinides, trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals and also from one or more of the substances in a group consisting of hexavalent actinides, trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals and also useful for separating hexavalent actinides from one or more of the substances in a group consisting of trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals.

Design, synthesis, and testing of multivalent compounds targeted to melanocortin receptors

NASA Astrophysics Data System (ADS)

Dehigaspitiya, Dilani Chathurika

Our focus is on developing non-invasive molecular imaging reagents, which target human cancers that presently are difficult to detect, such as melanoma. We wish to apply the multivalency concept to differentiate between healthy cells and melanoma cells. Melanoma cells are known to over-express alpha melanocyte stimulating hormone receptors. A successful multivalent construct should show greater avidity towards melanoma cells than healthy cells due to the synergistic effects arising from multivalency. Both oligomeric and shorter linear constructs bearing the minimum active sequence of melanocyte stimulating hormone, His-DPhe-Arg-Trp-NH2(MSH4), which binds with low micromolar affinity to alpha melanocyte stimulating hormone receptors, were synthesized. Binding affinities of these constructs were evaluated in a competitive binding assay by competing with labeled ligands, Eu-DTPA-PEGO-MSH7 and/or Eu-DTPA-PEGO-NDP-alpha-MSH on the engineered cell line HEK293 CCK2R/hMC4R, which is genetically modified to over-express both the cholecystokinin 2 receptor (CCK2R) and human melanocortin 4 receptor (hMC4R). The oligomers were rapidly assembled using microwave-assisted copper catalyzed azide-alkyne cycloaddition between a dialkyne derivative of MSH4 and a diazide derivative of (Pro-Gly)3 as co-monomers. Three oligomer mixtures were further analyzed based on their degree of oligomerization and the route by which the MSH4 monomers were oligomerized, protected vs deprotected. Completive binding assay against Eu-DTPA-PEGO-MSH7 showed only a statistical enhancement of binding when calculated based on the total MSH4 concentration. However, when the calculation of avidity is based on an estimation of the particles numbers, there was a seven times enhancement of binding compared to a monovalent MSH4 control. The shorter linear multivalent MSH4 constructs were synthesized using ethylene glycol, glycerol, and mannitol as core scaffolds with maximum inter-ligand distances ranging from 27 - 37 A. The divalent construct with maximum inter-ligand distance of 27 A showed nanomolar binding with 29-fold and 18-fold enhancements in potency compared to a monovalent control when competed against the probes Eu-DTPA-PEGO-MSH7 and Eu-DTPA-PEGO-NDP-alpha-MSH, respectively. The trivalent and the tetravalent constructs showed only statistical enhancement when compared to the divalent construct. It is our hypothesis that clusters of two ligands with an inter-ligand distance of about 27 A distributed along an oligomeric backbone would have high potency towards melanocortin receptors.

Genetic engineering of Ganoderma lucidum for the efficient production of ganoderic acids

PubMed Central

Xu, Jun-Wei; Zhong, Jian-Jiang

2015-01-01

Ganoderma lucidum is a well-known traditional medicinal mushroom that produces ganoderic acids with numerous interesting bioactivities. Genetic engineering is an efficient approach to improve ganoderic acid biosynthesis. However, reliable genetic transformation methods and appropriate genetic manipulation strategies remain underdeveloped and thus should be enhanced. We previously established a homologous genetic transformation method for G. lucidum; we also applied the established method to perform the deregulated overexpression of a homologous 3-hydroxy-3-methyl-glutaryl coenzyme A reductase gene in G. lucidum. Engineered strains accumulated more ganoderic acids than wild-type strains. In this report, the genetic transformation systems of G. lucidum are described; current trends are also presented to improve ganoderic acid production through the genetic manipulation of G. lucidum. PMID:26588475

Enriching rice with Zn and Fe while minimizing Cd risk

PubMed Central

Slamet-Loedin, Inez H.; Johnson-Beebout, Sarah E.; Impa, Somayanda; Tsakirpaloglou, Nikolaos

2015-01-01

Enriching iron (Fe) and zinc (Zn) content in rice grains, while minimizing cadmium (Cd) levels, is important for human health and nutrition. Natural genetic variation in rice grain Zn enables Zn-biofortification through conventional breeding, but limited natural Fe variation has led to a need for genetic modification approaches, including over-expressing genes responsible for Fe storage, chelators, and transporters. Generally, Cd uptake and allocation is associated with divalent metal cations (including Fe and Zn) transporters, but the details of this process are still unknown in rice. In addition to genetic variation, metal uptake is sometimes limited by its bioavailability in the soil. The availability of Fe, Zn, and Cd for plant uptake varies widely depending on soil redox potential. The typical practice of flooding rice increases Fe while decreasing Zn and Cd availability. On the other hand, moderate soil drying improves Zn uptake but also increases Cd and decreases Fe uptake. Use of Zn- or Fe-containing fertilizers complements breeding efforts by providing sufficient metals for plant uptake. In addition, the timing of nitrogen fertilization has also been shown to affect metal accumulation in grains. The purpose of this mini-review is to identify knowledge gaps and prioritize strategies for improving the nutritional value and safety of rice. PMID:25814994

Genetically engineered mouse models of melanoma.

PubMed

Pérez-Guijarro, Eva; Day, Chi-Ping; Merlino, Glenn; Zaidi, M Raza

2017-06-01

Melanoma is a complex disease that exhibits highly heterogeneous etiological, histopathological, and genetic features, as well as therapeutic responses. Genetically engineered mouse (GEM) models provide powerful tools to unravel the molecular mechanisms critical for melanoma development and drug resistance. Here, we expound briefly the basis of the mouse modeling design, the available technology for genetic engineering, and the aspects influencing the use of GEMs to model melanoma. Furthermore, we describe in detail the currently available GEM models of melanoma. Cancer 2017;123:2089-103. © 2017 American Cancer Society. © 2017 American Cancer Society.

Testing the Role of p21 Activated Kinases in Schwannoma Formation Using a Novel Genetically Engineered Murine Model that Closely Phenocopies Human NF2 Disease

DTIC Science & Technology

2017-06-01

Kinases in Schwannoma Formation Using a Novel Genetically Engineered Murine Model that Closely Phenocopies Human NF2 Disease The views, opinions and...Role of p21 Activated Kinases in Schwannoma Formation Using a Novel Genetically Engineered Murine Model that Closely Phenocopies Human NF2 Disease Form...NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. The major goal of this research project was to genetically and pharmacologically test the requirement of PAK

Building a Genome Engineering Toolbox in Non-Model Prokaryotic Microbes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eckert, Carrie A; Freed, Emily; Smolinski, Sharon

The realization of a sustainable bioeconomy requires our ability to understand and engineer complex design principles for the development of platform organisms capable of efficient conversion of cheap and sustainable feedstocks (e.g. sunlight, CO2, non-food biomass) to biofuels and bioproducts at sufficient titers and costs. For model microbes such as E. coli, advances in DNA reading and writing technologies are driving adoption of new paradigms for engineering biological systems. Unfortunately, microbes with properties of interest for the utilization of cheap and renewable feedstocks such as photosynthesis, autotrophic growth, and cellulose degradation have very few, if any, genetic tools for metabolicmore » engineering. Therefore, it is important to begin to develop 'design rules' for building a genetic toolbox for novel microbes. Here, we present an overview of our current understanding of these rules for the genetic manipulation of prokaryotic microbes and available genetic tools to expand our ability to genetically engineer non-model systems.« less

Reproductive cloning, genetic engineering and the autonomy of the child: the moral agent and the open future.

PubMed

Mameli, M

2007-02-01

Some authors have argued that the human use of reproductive cloning and genetic engineering should be prohibited because these biotechnologies would undermine the autonomy of the resulting child. In this paper, two versions of this view are discussed. According to the first version, the autonomy of cloned and genetically engineered people would be undermined because knowledge of the method by which these people have been conceived would make them unable to assume full responsibility for their actions. According to the second version, these biotechnologies would undermine autonomy by violating these people's right to an open future. There is no evidence to show that people conceived through cloning and genetic engineering would inevitably or even in general be unable to assume responsibility for their actions; there is also no evidence for the claim that cloning and genetic engineering would inevitably or even in general rob the child of the possibility to choose from a sufficiently large array of life plans.

Reproductive cloning, genetic engineering and the autonomy of the child: the moral agent and the open future

PubMed Central

Mameli, M

2007-01-01

Some authors have argued that the human use of reproductive cloning and genetic engineering should be prohibited because these biotechnologies would undermine the autonomy of the resulting child. In this paper, two versions of this view are discussed. According to the first version, the autonomy of cloned and genetically engineered people would be undermined because knowledge of the method by which these people have been conceived would make them unable to assume full responsibility for their actions. According to the second version, these biotechnologies would undermine autonomy by violating these people's right to an open future. There is no evidence to show that people conceived through cloning and genetic engineering would inevitably or even in general be unable to assume responsibility for their actions; there is also no evidence for the claim that cloning and genetic engineering would inevitably or even in general rob the child of the possibility to choose from a sufficiently large array of life plans. PMID:17264194

Current Progress of Genetically Engineered Pig Models for Biomedical Research

PubMed Central

Gün, Gökhan

2014-01-01

Abstract The first transgenic pigs were generated for agricultural purposes about three decades ago. Since then, the micromanipulation techniques of pig oocytes and embryos expanded from pronuclear injection of foreign DNA to somatic cell nuclear transfer, intracytoplasmic sperm injection-mediated gene transfer, lentiviral transduction, and cytoplasmic injection. Mechanistically, the passive transgenesis approach based on random integration of foreign DNA was developed to active genetic engineering techniques based on the transient activity of ectopic enzymes, such as transposases, recombinases, and programmable nucleases. Whole-genome sequencing and annotation of advanced genome maps of the pig complemented these developments. The full implementation of these tools promises to immensely increase the efficiency and, in parallel, to reduce the costs for the generation of genetically engineered pigs. Today, the major application of genetically engineered pigs is found in the field of biomedical disease modeling. It is anticipated that genetically engineered pigs will increasingly be used in biomedical research, since this model shows several similarities to humans with regard to physiology, metabolism, genome organization, pathology, and aging. PMID:25469311

Building a genome engineering toolbox in nonmodel prokaryotic microbes.

PubMed

Freed, Emily; Fenster, Jacob; Smolinski, Sharon L; Walker, Julie; Henard, Calvin A; Gill, Ryan; Eckert, Carrie A

2018-05-11

The realization of a sustainable bioeconomy requires our ability to understand and engineer complex design principles for the development of platform organisms capable of efficient conversion of cheap and sustainable feedstocks (e.g., sunlight, CO 2 , and nonfood biomass) into biofuels and bioproducts at sufficient titers and costs. For model microbes, such as Escherichia coli, advances in DNA reading and writing technologies are driving the adoption of new paradigms for engineering biological systems. Unfortunately, microbes with properties of interest for the utilization of cheap and renewable feedstocks, such as photosynthesis, autotrophic growth, and cellulose degradation, have very few, if any, genetic tools for metabolic engineering. Therefore, it is important to develop "design rules" for building a genetic toolbox for novel microbes. Here, we present an overview of our current understanding of these rules for the genetic manipulation of prokaryotic microbes and the available genetic tools to expand our ability to genetically engineer nonmodel systems. © 2018 Wiley Periodicals, Inc.

Redox-mediated regulation of connexin proteins; focus on nitric oxide.

PubMed

García, Isaac E; Sánchez, Helmuth A; Martínez, Agustín D; Retamal, Mauricio A

2018-01-01

Connexins are membrane proteins that form hemichannels and gap junction channels at the plasma membrane. Through these channels connexins participate in autocrine and paracrine intercellular communication. Connexin-based channels are tightly regulated by membrane potential, phosphorylation, pH, redox potential, and divalent cations, among others, and the imbalance of this regulation have been linked to many acquired and genetic diseases. Concerning the redox potential regulation, the nitric oxide (NO) has been described as a modulator of the hemichannels and gap junction channels properties. However, how NO regulates these channels is not well understood. In this mini-review, we summarize the current knowledge about the effects of redox potential focused in NO on the trafficking, formation and functional properties of hemichannels and gap junction channels. Copyright © 2017 Elsevier B.V. All rights reserved.

Calcium ions function as a booster of chromosome condensation

PubMed Central

Phengchat, Rinyaporn; Takata, Hideaki; Morii, Kenichi; Inada, Noriko; Murakoshi, Hideji; Uchiyama, Susumu; Fukui, Kiichi

2016-01-01

Chromosome condensation is essential for the faithful transmission of genetic information to daughter cells during cell division. The depletion of chromosome scaffold proteins does not prevent chromosome condensation despite structural defects. This suggests that other factors contribute to condensation. Here we investigated the contribution of divalent cations, particularly Ca2+, to chromosome condensation in vitro and in vivo. Ca2+ depletion caused defects in proper mitotic progression, particularly in chromosome condensation after the breakdown of the nuclear envelope. Fluorescence lifetime imaging microscopy-Förster resonance energy transfer and electron microscopy demonstrated that chromosome condensation is influenced by Ca2+. Chromosomes had compact globular structures when exposed to Ca2+ and expanded fibrous structures without Ca2+. Therefore, we have clearly demonstrated a role for Ca2+ in the compaction of chromatin fibres. PMID:27910894

Calcium ions function as a booster of chromosome condensation.

PubMed

Phengchat, Rinyaporn; Takata, Hideaki; Morii, Kenichi; Inada, Noriko; Murakoshi, Hideji; Uchiyama, Susumu; Fukui, Kiichi

2016-12-02

Chromosome condensation is essential for the faithful transmission of genetic information to daughter cells during cell division. The depletion of chromosome scaffold proteins does not prevent chromosome condensation despite structural defects. This suggests that other factors contribute to condensation. Here we investigated the contribution of divalent cations, particularly Ca 2+ , to chromosome condensation in vitro and in vivo. Ca 2+ depletion caused defects in proper mitotic progression, particularly in chromosome condensation after the breakdown of the nuclear envelope. Fluorescence lifetime imaging microscopy-Förster resonance energy transfer and electron microscopy demonstrated that chromosome condensation is influenced by Ca 2+ . Chromosomes had compact globular structures when exposed to Ca 2+ and expanded fibrous structures without Ca 2+ . Therefore, we have clearly demonstrated a role for Ca 2+ in the compaction of chromatin fibres.

X-ray crystal structure of divalent metal-activated ß-xyloisdase, RS223BX

USDA-ARS?s Scientific Manuscript database

We report the first X-ray structure of a glycoside hydrolase family 43 ß-xylosidase, RS223BX, which is strongly activated by the addition of divalent metal cations. The 2.69 Å structure reveals that the Ca2+ cation is located at the back of the active site pocket. The Ca2+ coordinates to H274 to sta...

Process for removing sulfur from coal

DOEpatents

Aida, T.; Squires, T.G.; Venier, C.G.

1983-08-11

A process is disclosed for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

Regulation by divalent cations of /sup 3/H-baclofen binding to GABA/sub B/ sites in rat cerebellar membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kato, K.; Goto, M.; Fukuda, H.

1983-02-21

When investigating the effects of divalent cations (Mg/sup 2 +/, Ca/sup 2 +/, Sr/sup 2 +/, Ba/sup 2 +/, Mn/sup 2 +/ and Ni/sup 2 +/) on /sup 3/H-baclofen binding to rat cerebellar synaptic membranes, we found that the specific binding of /sup 3/H-baclofen was not only dependent on divalent cations, but was increased dose-dependently in the presence of these cations. The effects were in the following order of potency: Mn/sup 2 +/ approx. = Ni/sup 2 +/ > Mg/sup 2 +/ > Ca/sup 2 +/ > Sr/sup 2 +/ > Ba/sup 2 +/. Scatchard analysis of the binding datamore » revealed a single component of the binding sites in the presence of 2.5 mM MgCl/sub 2/, 2.5 mM CaCl/sub 2/ or 0.3 mM MnCl/sub 2/ whereas two components appeared in the presence of 2.5 mM MnCl/sub 2/ or 1 mM NiCl/sub 2/. In the former, divalent cations altered the apparent affinity (K/sub d/) without affecting density of the binding sites (B/sub max/). In the latter, the high-affinity sites showed a higher affinity and lower density of the binding sites than did the single component of the former. As the maximal effects of four cations (Mg/sup 2 +/, Ca/sup 2 +/, Mn/sup 2 +/, and Ni/sup 2 +/) were not additive, there are probably common sites of action of these divalent cations. Among the ligands for GABA/sub B/ sites, the affinity for (-), (+) and (+/-)baclofen, GABA and ..beta..-phenyl GABA increased 2 - 6 fold in the presence of 2.5 mM MnCl/sub 2/, in comparison with that in HEPES-buffered Krebs solution (containing 2.5 mM CaCl/sub 2/ and 1.2 mM MgSO/sub 4/), whereas that for muscimol was decreased to one-fifth. Thus, the affinity of GABA/sub B/ sites for its ligands is probably regulated by divalent cations, through common sites of action.« less

Metabolic Engineering of Oleaginous Yeasts for Production of Fuels and Chemicals.

PubMed

Shi, Shuobo; Zhao, Huimin

2017-01-01

Oleaginous yeasts have been increasingly explored for production of chemicals and fuels via metabolic engineering. Particularly, there is a growing interest in using oleaginous yeasts for the synthesis of lipid-related products due to their high lipogenesis capability, robustness, and ability to utilize a variety of substrates. Most of the metabolic engineering studies in oleaginous yeasts focused on Yarrowia that already has plenty of genetic engineering tools. However, recent advances in systems biology and synthetic biology have provided new strategies and tools to engineer those oleaginous yeasts that have naturally high lipid accumulation but lack genetic tools, such as Rhodosporidium , Trichosporon , and Lipomyces . This review highlights recent accomplishments in metabolic engineering of oleaginous yeasts and recent advances in the development of genetic engineering tools in oleaginous yeasts within the last 3 years.

[Progress of research on genetic engineering antibody and its application in prevention and control of parasitic diseases].

PubMed

Yao, Yuan; Yu, Chuan-xin

2013-08-01

Antibody has extensive application prospects in the biomedical field. The inherent disadvantages of traditional polyclonal antibody and monoclonal antibody limit their application values. The humanized and fragmented antibody remodeling has given a rise to a series of genetic engineered antibody variant. This paper reviews the progress of research on genetic engineering antibody and its application in prevention and control of parasitic diseases.

Field performance of a genetically engineered strain of pink bollworm.

PubMed

Simmons, Gregory S; McKemey, Andrew R; Morrison, Neil I; O'Connell, Sinead; Tabashnik, Bruce E; Claus, John; Fu, Guoliang; Tang, Guolei; Sledge, Mickey; Walker, Adam S; Phillips, Caroline E; Miller, Ernie D; Rose, Robert I; Staten, Robert T; Donnelly, Christl A; Alphey, Luke

2011-01-01

Pest insects harm crops, livestock and human health, either directly or by acting as vectors of disease. The Sterile Insect Technique (SIT)--mass-release of sterile insects to mate with, and thereby control, their wild counterparts--has been used successfully for decades to control several pest species, including pink bollworm, a lepidopteran pest of cotton. Although it has been suggested that genetic engineering of pest insects provides potential improvements, there is uncertainty regarding its impact on their field performance. Discrimination between released and wild moths caught in monitoring traps is essential for estimating wild population levels. To address concerns about the reliability of current marking methods, we developed a genetically engineered strain of pink bollworm with a heritable fluorescent marker, to improve discrimination of sterile from wild moths. Here, we report the results of field trials showing that this engineered strain performed well under field conditions. Our data show that attributes critical to SIT in the field--ability to find a mate and to initiate copulation, as well as dispersal and persistence in the release area--were comparable between the genetically engineered strain and a standard strain. To our knowledge, these represent the first open-field experiments with a genetically engineered insect. The results described here provide encouragement for the genetic control of insect pests.

Using Genetically Engineered Animal Models in the Postgenomic Era to Understand Gene Function in Alcoholism

PubMed Central

Reilly, Matthew T.; Harris, R. Adron; Noronha, Antonio

2012-01-01

Over the last 50 years, researchers have made substantial progress in identifying genetic variations that underlie the complex phenotype of alcoholism. Not much is known, however, about how this genetic variation translates into altered biological function. Genetic animal models recapitulating specific characteristics of the human condition have helped elucidate gene function and the genetic basis of disease. In particular, major advances have come from the ability to manipulate genes through a variety of genetic technologies that provide an unprecedented capacity to determine gene function in the living organism and in alcohol-related behaviors. Even newer genetic-engineering technologies have given researchers the ability to control when and where a specific gene or mutation is activated or deleted, allowing investigators to narrow the role of the gene’s function to circumscribed neural pathways and across development. These technologies are important for all areas of neuroscience, and several public and private initiatives are making a new generation of genetic-engineering tools available to the scientific community at large. Finally, high-throughput “next-generation sequencing” technologies are set to rapidly increase knowledge of the genome, epigenome, and transcriptome, which, combined with genetically engineered mouse mutants, will enhance insight into biological function. All of these resources will provide deeper insight into the genetic basis of alcoholism. PMID:23134044

Using genetically engineered animal models in the postgenomic era to understand gene function in alcoholism.

PubMed

Reilly, Matthew T; Harris, R Adron; Noronha, Antonio

2012-01-01

Over the last 50 years, researchers have made substantial progress in identifying genetic variations that underlie the complex phenotype of alcoholism. Not much is known, however, about how this genetic variation translates into altered biological function. Genetic animal models recapitulating specific characteristics of the human condition have helped elucidate gene function and the genetic basis of disease. In particular, major advances have come from the ability to manipulate genes through a variety of genetic technologies that provide an unprecedented capacity to determine gene function in the living organism and in alcohol-related behaviors. Even newer genetic-engineering technologies have given researchers the ability to control when and where a specific gene or mutation is activated or deleted, allowing investigators to narrow the role of the gene's function to circumscribed neural pathways and across development. These technologies are important for all areas of neuroscience, and several public and private initiatives are making a new generation of genetic-engineering tools available to the scientific community at large. Finally, high-throughput "next-generation sequencing" technologies are set to rapidly increase knowledge of the genome, epigenome, and transcriptome, which, combined with genetically engineered mouse mutants, will enhance insight into biological function. All of these resources will provide deeper insight into the genetic basis of alcoholism.

Inverse Thio Effects in the Hepatitis Delta Virus Ribozyme Reveal that the Reaction Pathway Is Controlled by Metal Ion Charge Density

PubMed Central

2015-01-01

The hepatitis delta virus (HDV) ribozyme self-cleaves in the presence of a wide range of monovalent and divalent ions. Prior theoretical studies provided evidence that self-cleavage proceeds via a concerted or stepwise pathway, with the outcome dictated by the valency of the metal ion. In the present study, we measure stereospecific thio effects at the nonbridging oxygens of the scissile phosphate under a wide range of experimental conditions, including varying concentrations of diverse monovalent and divalent ions, and combine these with quantum mechanical/molecular mechanical (QM/MM) free energy simulations on the stereospecific thio substrates. The RP substrate gives large normal thio effects in the presence of all monovalent ions. The SP substrate also gives normal or no thio effects, but only for smaller monovalent and divalent cations, such as Li+, Mg2+, Ca2+, and Sr2+; in contrast, sizable inverse thio effects are found for larger monovalent and divalent cations, including Na+, K+, NH4+, and Ba2+. Proton inventories are found to be unity in the presence of the larger monovalent and divalent ions, but two in the presence of Mg2+. Additionally, rate–pH profiles are inverted for the low charge density ions, and only imidazole plus ammonium ions rescue an inactive C75Δ variant in the absence of Mg2+. Results from the thio effect experiments, rate–pH profiles, proton inventories, and ammonium/imidazole rescue experiments, combined with QM/MM free energy simulations, support a change in the mechanism of HDV ribozyme self-cleavage from concerted and metal ion-stabilized to stepwise and proton transfer-stabilized as the charge density of the metal ion decreases. PMID:25799319

Comparative sensitivity of rat cerebellar neurons to dysregulation of divalent cation homeostasis and cytotoxicity caused by methylmercury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, Joshua R.; Marty, M. Sue; Atchison, William D.

2005-11-01

The objective of the present study was to determine the relative effectiveness of methylmercury (MeHg) to alter divalent cation homeostasis and cause cell death in MeHg-resistant cerebellar Purkinje and MeHg-sensitive granule neurons. Application of 0.5-5 {mu}M MeHg to Purkinje and granule cells grown in culture caused a concentration- and time-dependent biphasic increase in fura-2 fluorescence. At 0.5 and 1 {mu}M MeHg, the elevations of fura-2 fluorescence induced by MeHg were biphasic in both cell types, but significantly delayed in Purkinje as compared to granule cells. Application of the heavy-metal chelator, TPEN, to Purkinje cells caused a precipitous decline in amore » proportion of the fura-2 fluorescence signal, indicating that MeHg causes release of Ca{sup 2+} and non-Ca{sup 2+} divalent cations. Purkinje cells were also more resistant than granule cells to the neurotoxic effects of MeHg. At 24.5 h after-application of 5 {mu}M MeHg, 97.7% of Purkinje cells were viable. At 3 {mu}M MeHg there was no detectable loss of Purkinje cell viability. In contrast, only 40.6% of cerebellar granule cells were alive 24.5 h after application of 3 {mu}M MeHg. In conclusion, Purkinje neurons in primary cultures appear to be more resistant to MeHg-induced dysregulation of divalent cation homeostasis and subsequent cell death when compared to cerebellar granule cells. There is a significant component of non-Ca{sup 2+} divalent cation released by MeHg in Purkinje neurons.« less

Reaction of N,N'-dimethylformamide and divalent viologen molecule to generate an organic dopant for molybdenum disulfide

NASA Astrophysics Data System (ADS)

Fukui, A.; Miura, K.; Ichimiya, H.; Tsurusaki, A.; Kariya, K.; Yoshimura, T.; Ashida, A.; Fujimura, N.; Kiriya, D.

2018-05-01

Tuning the carrier concentration is essential for semiconducting materials to apply optoelectronic devices. Molybdenum disulfide (MoS2) is a semiconducting material composed of atomically thin (˜0.7 nm thickness) layers. To dope thin MoS2, instead of using conventional atom/ion injection processes, a surface charge transfer method was successfully applied. In this study, we report a simple preparation method of a molecular dopant applicable to the doping process. The method follows a previous report for producing a molecular dopant, benzyl viologen (BV) which shows electron doping to MoS2. To prepare dopant BV molecules, a reduction process with a commercially available divalent BV by sodium borohydride (NaBH4) is required; however, the reaction requires a large consumption of NaBH4. NaBH4 drastically reacts with the solvent water itself. We found a reaction process of BV in an organic solvent, N,N'-dimethylformamide (DMF), by adding a small amount of water dissolving the divalent BV. The reaction is mild (at room temperature) and is autonomous once DMF comes into contact with the divalent BV aqueous solution. The reaction can be monitored with a UV-Vis spectrometer, and kinetic analysis indicates two reaction steps between divalent/monovalent/neutral viologen isomers. The product was soluble in toluene and did not dissolve in water, indicating it is similar to the reported dopant BV. The synthesized molecule was found to act as a dopant for MoS2 by applying a metal-oxide-semiconductor field-effect-transistor (MOSFET) structure. The process is a general method and applicable to other viologen-related dopants to tune the electronic structure of 2D materials to facilitate generating atomically thin devices.

Partitioning of dopant cations between β-tricalcium phosphate and fluorapatite

NASA Astrophysics Data System (ADS)

Jay, E. E.; Mallinson, P. M.; Fong, S. K.; Metcalfe, B. L.; Grimes, R. W.

2011-07-01

Mixed crystalline phase composite ceramics offer the possibility of partitioning defect species between the phases as well as occupancy of specific sites within a given phase. Here we use atomic scale simulations to study the site preference of an extensive range of divalent and trivalent substitutional ions across the five cation sites in β-tricalcium phosphate ( β-TCP) and the two cations sites in fluorapatite (FAp). This study indicates that in β-TCP small dopant species occupy the smaller of the five cation sites and vice versa. Conversely, in FAp, small divalent species occupy the nominally larger Ca(1) site while larger cations occupy the Ca(2) site. Partition energies between the two phases indicate that divalent species strongly segregate to β-TCP as do Al 3+ and Ga 3+, whereas all other (larger) trivalent ions exhibit little preference.

Virus resistant plums through genetic engineering - from lab to market

USDA-ARS?s Scientific Manuscript database

Genetic engineering (GE) has the potential to revolutionize the genetic improvement of fruit trees and other specialty crops, to provide greater flexibility and speed in responding to changes in climate, production systems and market demands, and to maintain the competitiveness of American agricultu...

A Genetically Engineered Mouse Model of Neuroblastoma Driven by Mutated ALK and MYCN

DTIC Science & Technology

2014-09-01

AWARD NUMBER: W81XWH-13-1-0220 TITLE: A Genetically Engineered Mouse Model of Neuroblastoma ...CONTRACT NUMBER A Genetically Engineered Mouse Model of Neuroblastoma Driven by Mutated ALK and MYCN 5b. GRANT NUMBER W81XWH-13-1-0220 5c...common ALK mutations in neuroblastoma , F1174L and R1275Q. We have determined that in tumors cells expressing mutated ALK, different downstream

Genetically Engineered Humanized Mouse Models for Preclinical Antibody Studies

PubMed Central

Proetzel, Gabriele; Wiles, Michael V.; Roopenian, Derry C.

2015-01-01

The use of genetic engineering has vastly improved our capabilities to create animal models relevant in preclinical research. With the recent advances in gene-editing technologies, it is now possible to very rapidly create highly tunable mouse models as needs arise. Here, we provide an overview of genetic engineering methods, as well as the development of humanized neonatal Fc receptor (FcRn) models and their use for monoclonal antibody in vivo studies. PMID:24150980

Developing Novel Therapeutic Approaches in Small Cell Lung Carcinoma Using Genetically Engineered Mouse Models and Human Circulating Tumor Cells

DTIC Science & Technology

2014-10-01

AD_________________ Award Number: W81XWH-13-1-0325 TITLE: Developing Novel Therapeutic Approaches in Small Cell Lung Carcinoma Using ...Genetically Engineered Mouse Models and Human Circulating Tumor Cells PRINCIPAL INVESTIGATOR: Jeffrey Engelman MD PhD CONTRACTING ORGANIZATION ...Novel Therapeutic Approaches in Small Cell Lung 5a. CONTRACT NUMBER W81XWH-13-1-0325 Carcinoma Using Genetically Engineered Mouse Models and 5b

Genetic engineering: a matter that requires further refinement in Spanish secondary school textbooks

NASA Astrophysics Data System (ADS)

Martínez-Gracia, M. V.; Gil-Quýlez, M. J.

2003-09-01

Genetic engineering is now an integral part of many high school textbooks but little work has been done to assess whether it is being properly addressed. A checklist with 19 items was used to analyze how genetic engineering is presented in biology textbooks commonly used in Spanish high schools, including the content, its relationship with fundamental genetic principles, and how it aims to improve the genetic literacy of students. The results show that genetic engineering was normally introduced without a clear reference to the universal genetic code, protein expression or the genetic material shared by all species. In most cases it was poorly defined, without a clear explanation of all the relevant processes involved. Some procedures (such as vectors) were explained in detail without considering previous student knowledge or skills. Some books emphasized applications such as the human genome project without describing DNA sequencing. All books included possible repercussions, but in most cases only fashionable topics such as human cloning. There was an excess of information that was not always well founded and hence was unsuitable to provide a meaningful understanding of DNA technology required for citizens in the twenty-first century.

Genetic diversity in natural populations of a soil bacterium across a landscape gradient

PubMed Central

McArthur, J. Vaun; Kovacic, David A.; Smith, Michael H.

1988-01-01

Genetic diversity in natural populations of the bacterium Pseudomonas cepacia was surveyed in 10 enzymes from 70 clones isolated along a landscape gradient. Estimates of genetic diversity, ranging from 0.54 to 0.70, were higher than any previously reported values of which we are aware and were positively correlated with habitat variability. Patterns of bacterial genetic diversity were correlated with habitat variability. Findings indicate that the source of strains used in genetic engineering will greatly affect the outcome of planned releases in variable environments. Selection of generalist strains may confer a large advantage to engineered populations, while selection of laboratory strains may result in quick elimination of the engineered strains. PMID:16594009

Interaction of divalent metal ions with human translocase of inner membrane of mitochondria Tim23.

PubMed

Feng, Wei; Zhang, Yongqiang; Deng, Honghua; Li, Shu Jie

2016-06-17

The preprotein translocase of the inner membrane of mitochondria (TIM23 complex) is the main entry gate for proteins of the matrix and the inner membrane. Tim23p, the core component of TIM23 complex, forms the import pore across the inner membrane and exerts a key function in the protein import. However, the interaction of divalent metal ions with Tim23p and the contribution in the interaction of presequence peptide with Tim23p are still unknown. Herein, we investigated the interaction of divalent metal ions with the intermembrane space domain of Tim23p (Tim23IMS) and the interaction of presequence peptides with Tim23IMS in presence of Ca(2+) ion by fluorescence spectroscopy in vitro. The static fluorescence quenching indicates the existence of strong binding between divalent metal ions and Tim23IMS. The order of the binding strength is Ca(2+), Mg(2+), Cu(2+), Mn(2+), and Co(2+) (from strong to weak). Moreover, the interaction of presequence peptides with Tim23IMS is weakened in presence of Ca(2+) ion, which implicates that Ca(2+) ion may play an important role in the protein import by TIM23 complex. Copyright © 2016 Elsevier Inc. All rights reserved.

Spectroscopic characterization of metal bound phytochelatin analogue (Glu-Cys)4-Gly.

PubMed

Cheng, Yongsheng; Yan, Yong-Bin; Liu, Jinyuan

2005-10-01

The metal ion binding properties of a phytochelatin (PC) analogue, (Glu-Cys)4-Gly (named as EC4), have been studied by a divalent metal ion binding assay monitored by UV-visible spectroscopy, circular dichroism and NMR spectroscopy. Spectro- photometric titration with different divalent metal ions have revealed that the stiochoimetry of metal-bound EC4 was 1:1, and its metal binding affinities with different divalent metal ions in the order of Cd(II)>Cu(II)>Zn(II)>Pb(II)>Ni(II)>Co(II). UV-visible spectroscopic analysis of metal complexes indicated that four sulfur atoms in cysteine residues are attributable to ligand-to-metal charge transfer (LMCT) between divalent metal ions and EC4, and further confirmed by 1D H1 NMR study and Circular Dichroism. In addition, Circular Dichroism spectra of both free and metal-bound forms of EC4 revealed that metal coordination drives the nonapeptide chain to fold into a turned conformation. The comprehensive analysis of spectroscopic properties of the nonapeptide complexed with metal ions not only provides a fundamental description of the metal ion binding properties of PC analogue, but also shows a correlation between metal binding affinity of PC analogue and the induction activity of metal ions.

Metabolic Engineering of Oleaginous Yeasts for Production of Fuels and Chemicals

PubMed Central

Shi, Shuobo; Zhao, Huimin

2017-01-01

Oleaginous yeasts have been increasingly explored for production of chemicals and fuels via metabolic engineering. Particularly, there is a growing interest in using oleaginous yeasts for the synthesis of lipid-related products due to their high lipogenesis capability, robustness, and ability to utilize a variety of substrates. Most of the metabolic engineering studies in oleaginous yeasts focused on Yarrowia that already has plenty of genetic engineering tools. However, recent advances in systems biology and synthetic biology have provided new strategies and tools to engineer those oleaginous yeasts that have naturally high lipid accumulation but lack genetic tools, such as Rhodosporidium, Trichosporon, and Lipomyces. This review highlights recent accomplishments in metabolic engineering of oleaginous yeasts and recent advances in the development of genetic engineering tools in oleaginous yeasts within the last 3 years. PMID:29167664

Genetically engineering milk.

PubMed

Whitelaw, C Bruce A; Joshi, Akshay; Kumar, Satish; Lillico, Simon G; Proudfoot, Chris

2016-02-01

It has been thirty years since the first genetically engineered animal with altered milk composition was reported. During the intervening years, the world population has increased from 5bn to 7bn people. An increasing demand for protein in the human diet has followed this population expansion, putting huge stress on the food supply chain. Many solutions to the grand challenge of food security for all have been proposed and are currently under investigation and study. Amongst these, genetics still has an important role to play, aiming to continually enable the selection of livestock with enhanced traits. Part of the geneticist's tool box is the technology of genetic engineering. In this Invited Review, we indicate that this technology has come a long way, we focus on the genetic engineering of dairy animals and we argue that the new strategies for precision breeding demand proper evaluation as to how they could contribute to the essential increases in agricultural productivity our society must achieve.

Engineering Values into Genetic Engineering: A Proposed Analytic Framework for Scientific Social Responsibility

PubMed Central

Cho, Mildred K.

2016-01-01

Recent experiments have been used to “edit” genomes of various plant, animal and other species, including humans, with unprecedented precision. Furthermore, editing Cas9 endonuclease gene with a gene encoding the desired guide RNA into an organism, adjacent to an altered gene, could create a “gene drive” that could spread a trait through an entire population of organisms. These experiments represent advances along a spectrum of technological abilities that genetic engineers have been working on since the advent of recombinant DNA techniques. The scientific and bioethics communities have built substantial literatures about the ethical and policy implications of genetic engineering, especially in the age of bioterrorism. However, recent CRISPr/Cas experiments have triggered a rehashing of previous policy discussions, suggesting that the scientific community requires guidance on how to think about social responsibility. We propose a framework to enable analysis of social responsibility, using two examples of genetic engineering experiments. PMID:26632356

Engineering Values Into Genetic Engineering: A Proposed Analytic Framework for Scientific Social Responsibility.

PubMed

Sankar, Pamela L; Cho, Mildred K

2015-01-01

Recent experiments have been used to "edit" genomes of various plant, animal and other species, including humans, with unprecedented precision. Furthermore, editing the Cas9 endonuclease gene with a gene encoding the desired guide RNA into an organism, adjacent to an altered gene, could create a "gene drive" that could spread a trait through an entire population of organisms. These experiments represent advances along a spectrum of technological abilities that genetic engineers have been working on since the advent of recombinant DNA techniques. The scientific and bioethics communities have built substantial literatures about the ethical and policy implications of genetic engineering, especially in the age of bioterrorism. However, recent CRISPr/Cas experiments have triggered a rehashing of previous policy discussions, suggesting that the scientific community requires guidance on how to think about social responsibility. We propose a framework to enable analysis of social responsibility, using two examples of genetic engineering experiments.

β1 Integrins Mediate Attachment of Mesenchymal Stem Cells to Cartilage Lesions

PubMed Central

Zwolanek, Daniela; Flicker, Magdalena; Kirstätter, Elisabeth; Zaucke, Frank; van Osch, Gerjo J.V.M.; Erben, Reinhold G.

2015-01-01

Abstract Mesenchymal stem cells (MSC) may have great potential for cell-based therapies of osteoarthritis. However, after injection in the joint, only few cells adhere to defective articular cartilage and contribute to cartilage regeneration. Little is known about the molecular mechanisms of MSC attachment to defective articular cartilage. Here, we developed an ex vivo attachment system, using rat osteochondral explants with artificially created full-thickness cartilage defects in combination with genetically labeled MSC isolated from bone marrow of human placental alkaline phosphatase transgenic rats. Binding of MSC to full-thickness cartilage lesions was improved by serum, but not hyaluronic acid, and was dependent on the presence of divalent cations. Additional in vitro tests showed that rat MSC attach, in a divalent cation-dependent manner, to collagen I, collagen II, and fibronectin, but not to collagen XXII or cartilage oligomeric matrix protein (COMP). RGD peptides partially blocked the adhesion of MSC to fibronectin in vitro and to cartilage lesions ex vivo. Furthermore, the attachment of MSC to collagen I and II in vitro and to cartilage lesions ex vivo was almost completely abolished in the presence of a β1 integrin blocking antibody. In conclusion, our data suggest that attachment of MSC to ex vivo full-thickness cartilage lesions is almost entirely β1 integrin-mediated, whereby both RGD- and collagen-binding integrins are involved. These findings suggest a key role of integrins during MSC attachment to defective cartilage and may pave the way for improved MSC-based therapies in the future. PMID:26309781

Assessment of the Requirements for Magnesium Transporters in Bacillus subtilis

PubMed Central

Wakeman, Catherine A.; Goodson, Jonathan R.; Zacharia, Vineetha M.

2014-01-01

Magnesium is the most abundant divalent metal in cells and is required for many structural and enzymatic functions. For bacteria, at least three families of proteins function as magnesium transporters. In recent years, it has been shown that a subset of these transport proteins is regulated by magnesium-responsive genetic control elements. In this study, we investigated the cellular requirements for magnesium homeostasis in the model microorganism Bacillus subtilis. Putative magnesium transporter genes were mutationally disrupted, singly and in combination, in order to assess their general importance. Mutation of only one of these genes resulted in strong dependency on supplemental extracellular magnesium. Notably, this transporter gene, mgtE, is known to be under magnesium-responsive genetic regulatory control. This suggests that the identification of magnesium-responsive genetic mechanisms may generally denote primary transport proteins for bacteria. To investigate whether B. subtilis encodes yet additional classes of transport mechanisms, suppressor strains that permitted the growth of a transporter-defective mutant were identified. Several of these strains were sequenced to determine the genetic basis of the suppressor phenotypes. None of these mutations occurred in transport protein homologues; instead, they affected housekeeping functions, such as signal recognition particle components and ATP synthase machinery. From these aggregate data, we speculate that the mgtE protein provides the primary route of magnesium import in B. subtilis and that the other putative transport proteins are likely to be utilized for more-specialized growth conditions. PMID:24415722

Genetic Engineering: The Modification of Man

ERIC Educational Resources Information Center

Sinsheimer, Robert L.

1970-01-01

Describes somatic and genetic manipulations of individual genotypes, using diabetes control as an example of the first mode that is potentially realizable be derepression or viral transduction of genes. Advocates the use of genetic engineering of the second mode to remove man from his biological limitations, but offers maxims to ensure the…

Current achievements and future directions in genetic engineering of european plum (Prunus domestica L.)

USDA-ARS?s Scientific Manuscript database

In most woody fruit species, transformation and regeneration are difficult. However, European plum (Prunus domestica) has been shown to be amenable to genetic improvement technologies from classical hybridization, to genetic engineering, to rapid cycle crop breeding (‘FasTrack’ breeding). Since th...

Chapter VIII. Contributions of propagation techniques and genetic modification to breeding - genetic engineering for disease resistance

USDA-ARS?s Scientific Manuscript database

Genetic engineering offers an opportunity to develop flower bulb crops with resistance to fungal, viral, and bacterial pathogens. Several of the flower bulb crops, Lilium spp., Gladiolus, Zantedeschia, Muscari, Hyacinthus, Narcissus, Ornithogalum, Iris, and Alstroemeria, have been transformed with t...

77 FR 41356 - Monsanto Co.; Availability of Petition for Determination of Nonregulated Status of Soybean...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... Engineered for Herbicide Tolerance AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Notice... soybean designated as MON 87708, which has been genetically engineered for tolerance to the herbicide... MON 87708, which has been genetically engineered for tolerance to the herbicide dicamba, stating that...

77 FR 41353 - GENECTIVE SA; Availability of Petition for Determination of Nonregulated Status of Maize...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... Engineered for Herbicide Tolerance AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Notice... VCO-[Oslash]1981-5, which has been genetically engineered for tolerance to the herbicide glyphosate...- [Oslash]1981-5, which has been genetically engineered for tolerance to the herbicide glyphosate, stating...

Perspectives for genetic engineering for the phytoremediation of arsenic-contaminated environments: from imagination to reality?

PubMed

Zhu, Yong-Guan; Rosen, Barry P

2009-04-01

Phytoremediation to clean up arsenic-contaminated environments has been widely hailed as environmentally friendly and cost effective, and genetic engineering is believed to improve the efficiency and versatility of phytoremediation. Successful genetic engineering requires the thorough understanding of the mechanisms involved in arsenic tolerance and accumulation by natural plant species. Key mechanisms include arsenate reduction, arsenic sequestration in vacuoles of root or shoot, arsenic loading to the xylem, and volatilization through the leaves. Key advances include the identification of arsenic (As) translocation from root to shoot in the As hyperaccumulator, Pteris vittata, and the characterization of related key genes from hyperaccumulator and nonaccumulators. In this paper we have proposed three pathways for genetic engineering: arsenic sequestration in the root, hyperaccumulation of arsenic in aboveground tissues, and phytovolatilization.

A Hybrid Neural Network-Genetic Algorithm Technique for Aircraft Engine Performance Diagnostics

NASA Technical Reports Server (NTRS)

Kobayashi, Takahisa; Simon, Donald L.

2001-01-01

In this paper, a model-based diagnostic method, which utilizes Neural Networks and Genetic Algorithms, is investigated. Neural networks are applied to estimate the engine internal health, and Genetic Algorithms are applied for sensor bias detection and estimation. This hybrid approach takes advantage of the nonlinear estimation capability provided by neural networks while improving the robustness to measurement uncertainty through the application of Genetic Algorithms. The hybrid diagnostic technique also has the ability to rank multiple potential solutions for a given set of anomalous sensor measurements in order to reduce false alarms and missed detections. The performance of the hybrid diagnostic technique is evaluated through some case studies derived from a turbofan engine simulation. The results show this approach is promising for reliable diagnostics of aircraft engines.

Genetic tool development and systemic regulation in biosynthetic technology.

PubMed

Dai, Zhongxue; Zhang, Shangjie; Yang, Qiao; Zhang, Wenming; Qian, Xiujuan; Dong, Weiliang; Jiang, Min; Xin, Fengxue

2018-01-01

With the increased development in research, innovation, and policy interest in recent years, biosynthetic technology has developed rapidly, which combines engineering, electronics, computer science, mathematics, and other disciplines based on classical genetic engineering and metabolic engineering. It gives a wider perspective and a deeper level to perceive the nature of life via cell mechanism, regulatory networks, or biological evolution. Currently, synthetic biology has made great breakthrough in energy, chemical industry, and medicine industries, particularly in the programmable genetic control at multiple levels of regulation to perform designed goals. In this review, the most advanced and comprehensive developments achieved in biosynthetic technology were represented, including genetic engineering as well as synthetic genomics. In addition, the superiority together with the limitations of the current genome-editing tools were summarized.

Genome engineering in cattle: recent technological advancements.

PubMed

Wang, Zhongde

2015-02-01

Great strides in technological advancements have been made in the past decade in cattle genome engineering. First, the success of cloning cattle by somatic cell nuclear transfer (SCNT) or chromatin transfer (CT) is a significant advancement that has made obsolete the need for using embryonic stem (ES) cells to conduct cell-mediated genome engineering, whereby site-specific genetic modifications can be conducted in bovine somatic cells via DNA homologous recombination (HR) and whereby genetically engineered cattle can subsequently be produced by animal cloning from the genetically modified cells. With this approach, a chosen bovine genomic locus can be precisely modified in somatic cells, such as to knock out (KO) or knock in (KI) a gene via HR, a gene-targeting strategy that had almost exclusively been used in mouse ES cells. Furthermore, by the creative application of embryonic cloning to rejuvenate somatic cells, cattle genome can be sequentially modified in the same line of somatic cells and complex genetic modifications have been achieved in cattle. Very recently, the development of designer nucleases-such as zinc finger nucleases (ZFNs) and transcription activator-like effector nuclease (TALENs), and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-has enabled highly efficient and more facile genome engineering in cattle. Most notably, by employing such designer nucleases, genomes can be engineered at single-nucleotide precision; this process is now often referred to as genome or gene editing. The above achievements are a drastic departure from the traditional methods of creating genetically modified cattle, where foreign DNAs are randomly integrated into the animal genome, most often along with the integrations of bacterial or viral DNAs. Here, I review the most recent technological developments in cattle genome engineering by highlighting some of the major achievements in creating genetically engineered cattle for agricultural and biomedical applications.

Engineering Bacterial Thiosulfate and Tetrathionate Sensors for Detecting Gut Inflammation

DTIC Science & Technology

2017-04-03

Article Engineering bacterial thiosulfate and tetrathionate sensors for detecting gut inflammation Kristina N-M Daeffler1 , Jeffrey D Galley2, Ravi U...interest in using genetically engineered sensor bacteria to study gut microbiota pathways, and diagnose or treat associated diseases. Here, we...understood. Genetically engineered sensor bacteria have untapped potential as tools for analyzing gut pathways. Bacteria have evolved sensors of a large

Two Active Site Divalent Ions in the Crystal Structure of the Hammerhead Ribozyme Bound to a Transition State Analogue.

PubMed

Mir, Aamir; Golden, Barbara L

2016-02-02

The crystal structure of the hammerhead ribozyme bound to the pentavalent transition state analogue vanadate reveals significant rearrangements relative to the previously determined structures. The active site contracts, bringing G10.1 closer to the cleavage site and repositioning a divalent metal ion such that it could, ultimately, interact directly with the scissile phosphate. This ion could also position a water molecule to serve as a general acid in the cleavage reaction. A second divalent ion is observed coordinated to O6 of G12. This metal ion is well-placed to help tune the pKA of G12. On the basis of this crystal structure as well as a wealth of biochemical studies, we propose a mechanism in which G12 serves as the general base and a magnesium-bound water serves as a general acid.

Response of a benzoxainone derivative linked to monoaza-15-crown-5 with divalent heavy metals.

PubMed

Addleman, R S; Bennett, J; Tweedy, S H; Elshani, S; Wai, C M

1998-08-01

The response of a monoaza-15-crown-5 with an optically active aminobenzoxazinone moiety to divalent cations was investigated. The crown ether was found to undergo a strong emission shift to the blue when complexed with specific divalent metals that have ionic diameters between 1.9-2.4 A. Consequently the photoactive macrocycle is responsive to Mg(2+), Ca(2+), Ba(2+), Sr(2+), Cd(2+), and particularly responsive to Hg(2+)and Pb(2+). Macrocycle emission spectra are shown to be a function of cation concentration. Alkaline metal cations and smaller transition metals ions such as Ni(2+), Co(2+)and Zn(2+)do not cause significant changes in the macrocycle emission spectra. Emission, absorption, and complex stability constants are determined. Mechanisms of cation selectivity and spectral emission shifts are discussed. Challenges involving immobilization of the macrocycle while preserving its spectral response to cations are explored.

Two active site divalent ions in the crystal structure of the hammerhead ribozyme bound to a transition state analogue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mir, Aamir; Golden, Barbara L.

2015-11-09

The crystal structure of the hammerhead ribozyme bound to the pentavalent transition state analogue vanadate reveals significant rearrangements relative to the previously determined structures. The active site contracts, bringing G10.1 closer to the cleavage site and repositioning a divalent metal ion such that it could, ultimately, interact directly with the scissile phosphate. This ion could also position a water molecule to serve as a general acid in the cleavage reaction. A second divalent ion is observed coordinated to O6 of G12. This metal ion is well-placed to help tune the p K A of G12. Finally, on the basis ofmore » this crystal structure as well as a wealth of biochemical studies, in this paper we propose a mechanism in which G12 serves as the general base and a magnesium-bound water serves as a general acid.« less

Strong activation of bile acid-sensitive ion channel (BASIC) by ursodeoxycholic acid

PubMed Central

Wiemuth, Dominik; Sahin, Hacer; Lefèvre, Cathérine M.T.; Wasmuth, Hermann E.; Gründer, Stefan

2013-01-01

Bile acid-sensitive ion channel (BASIC) is a member of the DEG/ENaC gene family of unknown function. Rat BASIC (rBASIC) is inactive at rest. We have recently shown that cholangiocytes, the epithelial cells lining the bile ducts, are the main site of BASIC expression in the liver and identified bile acids, in particular hyo- and chenodeoxycholic acid, as agonists of rBASIC. Moreover, it seems that extracellular divalent cations stabilize the resting state of rBASIC, because removal of extracellular divalent cations opens the channel. In this addendum, we demonstrate that removal of extracellular divalent cations potentiates the activation of rBASIC by bile acids, suggesting an allosteric mechanism. Furthermore, we show that rBASIC is strongly activated by the anticholestatic bile acid ursodeoxycholic acid (UDCA), suggesting that BASIC might mediate part of the therapeutic effects of UDCA. PMID:23064163

Interpretation with a Donnan-based concept of the influence of simple salt concentration on the apparent binding of divalent ions to the polyelectrolytes polystyrenesulfonate and dextran sulfate

USGS Publications Warehouse

Marinsky, J.A.; Baldwin, Robert F.; Reddy, M.M.

1985-01-01

It has been shown that the apparent enhancement of divalent metal ion binding to polyions such as polystyrenesulfonate (PSS) and dextran sulfate (DS) by decreasing the ionic strength of these mixed counterion systems (M2+, M+, X-, polyion) can be anticipated with the Donnan-based model developed by one of us (J.A.M.). Ion-exchange distribution methods have been employed to measure the removal by the polyion of trace divalent metal ion from simple salt (NaClO4)-polyion (NaPSS) mixtures. These data and polyion interaction data published earlier by Mattai and Kwak for the mixed counterion systems MgCl2-LiCl-DS and MgCl2-CsCl-DS have been shown to be amenable to rather precise analysis by this model. ?? 1985 American Chemical Society.

Current achievements and future directions in genetic engineering of European plum (Prunus domestica L.).

PubMed

Petri, Cesar; Alburquerque, Nuria; Faize, Mohamed; Scorza, Ralph; Dardick, Chris

2018-06-01

In most woody fruit species, transformation and regeneration are difficult. However, European plum (Prunus domestica) has been shown to be amenable to genetic improvement technologies from classical hybridization, to genetic engineering, to rapid cycle crop breeding ('FasTrack' breeding). Since the first report on European plum transformation with marker genes in the early 90 s, numerous manuscripts have been published reporting the generation of new clones with agronomically interesting traits, such as pests, diseases and/or abiotic stress resistance, shorter juvenile period, dwarfing, continuous flowering, etc. This review focuses on the main advances in genetic transformation of European plum achieved to date, and the lines of work that are converting genetic engineering into a contemporary breeding tool for this species.

GMOs in Russia: Research, Society and Legislation.

PubMed

Korobko, I V; Georgiev, P G; Skryabin, K G; Kirpichnikov, M P

2016-01-01

Russian legislation lags behind the rapid developments witnessed in genetic engineering. Only a scientifically based and well-substantiated policy on the place of organisms that are created with the use of genetic engineering technologies and an assessment of the risks associated with them could guarantee that the breakthroughs achieved in modern genetic engineering technologies are effectively put to use in the real economy. A lack of demand for such breakthroughs in the practical field will lead to stagnation in scientific research and to a loss of expertise.

Effect of synthetic auxin herbicides on seed development and viability in genetically-engineered glyphosate-resistant alfalfa

USDA-ARS?s Scientific Manuscript database

Feral populations of cultivated crops have the potential to function as bridges and reservoirs that contribute to the unwanted movement of novel genetically engineered (GE) traits. Recognizing that feral alfalfa has the potential to lower genetic purity in alfalfa seed production fields when it is g...

Generating Alternative Engineering Designs by Integrating Desktop VR with Genetic Algorithms

ERIC Educational Resources Information Center

Chandramouli, Magesh; Bertoline, Gary; Connolly, Patrick

2009-01-01

This study proposes an innovative solution to the problem of multiobjective engineering design optimization by integrating desktop VR with genetic computing. Although, this study considers the case of construction design as an example to illustrate the framework, this method can very much be extended to other engineering design problems as well.…

78 FR 13305 - Syngenta Seeds, Inc., and Bayer CropScience AG; Availability of Petition for Determination of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-27

... Status of Soybean Genetically Engineered for Herbicide Tolerance AGENCY: Animal and Plant Health... SYHTOH2, which has been genetically engineered for tolerance to the herbicides glufosinate and mesotrione... engineered to tolerate exposure to the herbicides glufosinate and mesotrione. Glufosinate tolerance is not a...

75 FR 2845 - ArborGen, LLC; Availability of an Environmental Assessment for Controlled Release of a...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-19

... Engineered Eucalyptus Hybrid AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Notice... for a proposed controlled field release of a genetically engineered clone of a Eucalyptus hybrid. This... proposed controlled field release of a genetically engineered clone of a Eucalyptus hybrid. \\1\\ To view the...

"Genetic Engineering" Gains Momentum (Science/Society Case Study).

ERIC Educational Resources Information Center

Moore, John W.; Moore, Elizabeth A., Eds.

1980-01-01

Reviews the benefits and hazards of genetic engineering, or "recombinant-DNA" research. Recent federal safety rules issued by NIH which ease the strict prohibitions on recombinant-DNA research are explained. (CS)

Computer-aided design for metabolic engineering.

PubMed

Fernández-Castané, Alfred; Fehér, Tamás; Carbonell, Pablo; Pauthenier, Cyrille; Faulon, Jean-Loup

2014-12-20

The development and application of biotechnology-based strategies has had a great socio-economical impact and is likely to play a crucial role in the foundation of more sustainable and efficient industrial processes. Within biotechnology, metabolic engineering aims at the directed improvement of cellular properties, often with the goal of synthesizing a target chemical compound. The use of computer-aided design (CAD) tools, along with the continuously emerging advanced genetic engineering techniques have allowed metabolic engineering to broaden and streamline the process of heterologous compound-production. In this work, we review the CAD tools available for metabolic engineering with an emphasis, on retrosynthesis methodologies. Recent advances in genetic engineering strategies for pathway implementation and optimization are also reviewed as well as a range of bionalytical tools to validate in silico predictions. A case study applying retrosynthesis is presented as an experimental verification of the output from Retropath, the first complete automated computational pipeline applicable to metabolic engineering. Applying this CAD pipeline, together with genetic reassembly and optimization of culture conditions led to improved production of the plant flavonoid pinocembrin. Coupling CAD tools with advanced genetic engineering strategies and bioprocess optimization is crucial for enhanced product yields and will be of great value for the development of non-natural products through sustainable biotechnological processes. Copyright © 2014 Elsevier B.V. All rights reserved.

Genetically Engineered Mouse Models for Studying Inflammatory Bowel Disease

PubMed Central

Mizoguchi, Atsushi; Takeuchi, Takahito; Himuro, Hidetomo; Okada, Toshiyuki; Mizoguchi, Emiko

2015-01-01

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition that is mediated by very complex mechanisms controlled by genetic, immune, and environmental factors. More than 74 kinds of genetically engineered mouse strains have been established since 1993 for studying IBD. Although mouse models cannot fully reflect human IBD, they have provided significant contributions for not only understanding the mechanism, but also developing new therapeutic means for IBD. Indeed, 20 kinds of genetically engineered mouse models carry the susceptibility genes identified in human IBD, and the functions of some other IBD susceptibility genes have also been dissected out using mouse models. Cutting-edge technologies such as cell-specific and inducible knockout systems, which were recently employed to mouse IBD models, have further enhanced the ability of investigators to provide important and unexpected rationales for developing new therapeutic strategies for IBD. In this review article, we briefly introduce 74 kinds of genetically engineered mouse models that spontaneously develop intestinal inflammation. PMID:26387641

Perspectives for genetic engineering for the phytoremediation of arsenic-contaminated environments: from imagination to reality?

PubMed Central

Zhu, Yong-Guan; Rosen, Barry P

2015-01-01

Phytoremediation to clean up arsenic-contaminated environments has been widely hailed as environmentally friendly and cost effective, and genetic engineering is believed to improve the efficiency and versatility of phytoremediation. Successful genetic engineering requires the thorough understanding of the mechanisms involved in arsenic tolerance and accumulation by natural plant species. Key mechanisms include arsenate reduction, arsenic sequestration in vacuoles of root or shoot, arsenic loading to the xylem, and volatilization through the leaves. Key advances include the identification of arsenic (As) translocation from root to shoot in the As hyperaccumulator, Pteris vittata, and the characterization of related key genes from hyperaccumulator and nonaccumulators. In this paper we have proposed three pathways for genetic engineering: arsenic sequestration in the root, hyperaccumulation of arsenic in aboveground tissues, and phytovolatilization. PMID:19303764

Emergency deployment of genetically engineered veterinary vaccines in Europe.

PubMed

Ramezanpour, Bahar; de Foucauld, Jean; Kortekaas, Jeroen

2016-06-24

On the 9th of November 2015, preceding the World Veterinary Vaccine Congress, a workshop was held to discuss how veterinary vaccines can be deployed more rapidly to appropriately respond to future epizootics in Europe. Considering their potential and unprecedented suitability for surge production, the workshop focussed on vaccines based on genetically engineered viruses and replicon particles. The workshop was attended by academics and representatives from leading pharmaceutical companies, regulatory experts, the European Medicines Agency and the European Commission. We here outline the present regulatory pathways for genetically engineered vaccines in Europe and describe the incentive for the organization of the pre-congress workshop. The participants agreed that existing European regulations on the deliberate release of genetically engineered vaccines into the environment should be updated to facilitate quick deployment of these vaccines in emergency situations. Copyright © 2016.

Influence of ionic strength, anions, cations, and natural organic matter on the adsorption of pharmaceuticals to silica.

PubMed

Bui, Tung Xuan; Choi, Heechul

2010-08-01

The adsorption of four wide-use pharmaceuticals (carbamazepine, diclofenac, ibuprofen, and ketoprofen) onto a porous silica was investigated under varied ionic strengths, different anions, divalent cations (Ca(2+) and Mg(2+)), trivalent cations (Al(3+) and Fe(3+)), and natural organic matter (NOM). The experiments demonstrated that at a given pH the adsorption was most affected by ionic strength, trivalent cations, and properties of pharmaceuticals. The increase of ionic strength resulted in an increase in the adsorption of ketoprofen, but a decrease in the adsorption of carbamazepine. Trivalent metal cations made intense increases in the adsorption of three acidic pharmaceuticals, which could be due to the formation of inner-sphere complex of the cations on the surface and/or complexation of the pharmaceuticals with both surface and aqueous metal species. It was found that the adsorption of carbamazepine was not affected by divalent and trivalent cations, whereas the adsorption of diclofenac was solely impacted by the presence of Al(3+). Moreover, divalent cations at low concentration could slightly enhance the adsorption of ibuprofen and ketoprofen, whereas NOM caused a reduction in the adsorption of the tested pharmaceuticals except for diclofenac. These results suggest that ionic strength, divalent cations, trivalent cations, and NOM are notable factors affecting the adsorption of pharmaceuticals and thus the ultimate fate of pharmaceuticals in the aqueous environment. Copyright 2010 Elsevier Ltd. All rights reserved.

Role of Metal Ions on the Activity of Mycobacterium tuberculosis Pyrazinamidase

PubMed Central

Sheen, Patricia; Ferrer, Patricia; Gilman, Robert H.; Christiansen, Gina; Moreno-Román, Paola; Gutiérrez, Andrés H.; Sotelo, Jun; Evangelista, Wilfredo; Fuentes, Patricia; Rueda, Daniel; Flores, Myra; Olivera, Paula; Solis, José; Pesaresi, Alessandro; Lamba, Doriano; Zimic, Mirko

2012-01-01

Pyrazinamidase of Mycobacterium tuberculosis catalyzes the conversion of pyrazinamide to the active molecule pyrazinoic acid. Reduction of pyrazinamidase activity results in a level of pyrazinamide resistance. Previous studies have suggested that pyrazinamidase has a metal-binding site and that a divalent metal cofactor is required for activity. To determine the effect of divalent metals on the pyrazinamidase, the recombinant wild-type pyrazinamidase corresponding to the H37Rv pyrazinamide-susceptible reference strain was expressed in Escherichia coli with and without a carboxy terminal. His-tagged pyrazinamidase was inactivated by metal depletion and reactivated by titration with divalent metals. Although Co2+, Mn2+, and Zn2+ restored pyrazinamidase activity, only Co2+ enhanced the enzymatic activity to levels higher than the wild-type pyrazinamidase. Cu2+, Fe2+, Fe3+, and Mg2+ did not restore the activity under the conditions tested. Various recombinant mutated pyrazinamidases with appropriate folding but different enzymatic activities showed a differential pattern of recovered activity. X-ray fluorescence and atomic absorbance spectroscopy showed that recombinant wild-type pyrazinamidase expressed in E. coli most likely contained Zn. In conclusion, this study suggests that M. tuberculosis pyrazinamidase is a metalloenzyme that is able to coordinate several ions, but in vivo, it is more likely to coordinate Zn2+. However, in vitro, the metal-depleted enzyme could be reactivated by several divalent metals with higher efficiency than Zn. PMID:22764307

Salinity-Dependent Contact Angle Alteration in Oil/Brine/Silicate Systems: the Critical Role of Divalent Cations

PubMed Central

2017-01-01

The effectiveness of water flooding oil recovery depends to an important extent on the competitive wetting of oil and water on the solid rock matrix. Here, we use macroscopic contact angle goniometry in highly idealized model systems to evaluate how brine salinity affects the balance of wetting forces and to infer the microscopic origin of the resultant contact angle alteration. We focus, in particular, on two competing mechanisms debated in the literature, namely, double-layer expansion and divalent cation bridging. Our experiments involve aqueous droplets with a variable content of chloride salts of Na+, K+, Ca2+, and Mg2+, wetting surfaces of muscovite and amorphous silica, and an environment of ambient decane containing small amounts of fatty acids to represent polar oil components. By diluting the salt content in various manners, we demonstrate that the water contact angle on muscovite, not on silica, decreases by up to 25° as the divalent cation concentration is reduced from typical concentrations in seawater to zero. Decreasing the ionic strength at a constant divalent ion concentration, however, has a negligible effect on the contact angle. We discuss the consequences for the interpretation of core flooding experiments and the identification of a microscopic mechanism of low salinity water flooding, an increasingly popular, inexpensive, and environment-friendly technique for enhanced oil recovery. PMID:28332396

Salinity-Dependent Contact Angle Alteration in Oil/Brine/Silicate Systems: the Critical Role of Divalent Cations.

PubMed

Haagh, M E J; Siretanu, I; Duits, M H G; Mugele, F

2017-04-11

The effectiveness of water flooding oil recovery depends to an important extent on the competitive wetting of oil and water on the solid rock matrix. Here, we use macroscopic contact angle goniometry in highly idealized model systems to evaluate how brine salinity affects the balance of wetting forces and to infer the microscopic origin of the resultant contact angle alteration. We focus, in particular, on two competing mechanisms debated in the literature, namely, double-layer expansion and divalent cation bridging. Our experiments involve aqueous droplets with a variable content of chloride salts of Na + , K + , Ca 2+ , and Mg 2+ , wetting surfaces of muscovite and amorphous silica, and an environment of ambient decane containing small amounts of fatty acids to represent polar oil components. By diluting the salt content in various manners, we demonstrate that the water contact angle on muscovite, not on silica, decreases by up to 25° as the divalent cation concentration is reduced from typical concentrations in seawater to zero. Decreasing the ionic strength at a constant divalent ion concentration, however, has a negligible effect on the contact angle. We discuss the consequences for the interpretation of core flooding experiments and the identification of a microscopic mechanism of low salinity water flooding, an increasingly popular, inexpensive, and environment-friendly technique for enhanced oil recovery.

Pluripotent stem cells and livestock genetic engineering

PubMed Central

Soto, Delia A.

2016-01-01

The unlimited proliferative ability and capacity to contribute to germline chimeras make pluripotent embryonic stem cells (ESCs) perfect candidates for complex genetic engineering. The utility of ESCs is best exemplified by the numerous genetic models that have been developed in mice, for which such cells are readily available. However, the traditional systems for mouse genetic engineering may not be practical for livestock species, as it requires several generations of mating and selection in order to establish homozygous founders. Nevertheless, the self-renewal and pluripotent characteristics of ESCs could provide advantages for livestock genetic engineering such as ease of genetic manipulation and improved efficiency of cloning by nuclear transplantation. These advantages have resulted in many attempts to isolate livestock ESCs, yet it has been generally concluded that the culture conditions tested so far are not supportive of livestock ESCs self-renewal and proliferation. In contrast, there are numerous reports of derivation of livestock induced pluripotent stem cells (iPSCs), with demonstrated capacity for long term proliferation and in vivo pluripotency, as indicated by teratoma formation assay. However, to what extent these iPSCs represent fully reprogrammed PSCs remains controversial, as most livestock iPSCs depend on continuous expression of reprogramming factors. Moreover, germline chimerism has not been robustly demonstrated, with only one successful report with very low efficiency. Therefore, even 34 years after derivation of mouse ESCs and their extensive use in the generation of genetic models, the livestock genetic engineering field can stand to gain enormously from continued investigations into the derivation and application of ESCs and iPSCs. PMID:26894405

Pluripotent stem cells and livestock genetic engineering.

PubMed

Soto, Delia A; Ross, Pablo J

2016-06-01

The unlimited proliferative ability and capacity to contribute to germline chimeras make pluripotent embryonic stem cells (ESCs) perfect candidates for complex genetic engineering. The utility of ESCs is best exemplified by the numerous genetic models that have been developed in mice, for which such cells are readily available. However, the traditional systems for mouse genetic engineering may not be practical for livestock species, as it requires several generations of mating and selection in order to establish homozygous founders. Nevertheless, the self-renewal and pluripotent characteristics of ESCs could provide advantages for livestock genetic engineering such as ease of genetic manipulation and improved efficiency of cloning by nuclear transplantation. These advantages have resulted in many attempts to isolate livestock ESCs, yet it has been generally concluded that the culture conditions tested so far are not supportive of livestock ESCs self-renewal and proliferation. In contrast, there are numerous reports of derivation of livestock induced pluripotent stem cells (iPSCs), with demonstrated capacity for long term proliferation and in vivo pluripotency, as indicated by teratoma formation assay. However, to what extent these iPSCs represent fully reprogrammed PSCs remains controversial, as most livestock iPSCs depend on continuous expression of reprogramming factors. Moreover, germline chimerism has not been robustly demonstrated, with only one successful report with very low efficiency. Therefore, even 34 years after derivation of mouse ESCs and their extensive use in the generation of genetic models, the livestock genetic engineering field can stand to gain enormously from continued investigations into the derivation and application of ESCs and iPSCs.

The Significance of Content Knowledge for Informal Reasoning regarding Socioscientific Issues: Applying Genetics Knowledge to Genetic Engineering Issues

ERIC Educational Resources Information Center

Sadler, Troy D.; Zeidler, Dana L.

2005-01-01

This study focused on informal reasoning regarding socioscientific issues. It sought to explore how content knowledge influenced the negotiation and resolution of contentious and complex scenarios based on genetic engineering. Two hundred and sixty-nine students drawn from undergraduate natural science and nonnatural science courses completed a…

Teaching Applied Genetics and Molecular Biology to Agriculture Engineers. Application of the European Credit Transfer System

ERIC Educational Resources Information Center

Weiss, J.; Egea-Cortines, M.

2008-01-01

We have been teaching applied molecular genetics to engineers and adapted the teaching methodology to the European Credit Transfer System. We teach core principles of genetics that are universal and form the conceptual basis of most molecular technologies. The course then teaches widely used techniques and finally shows how different techniques…

Registration of Dicamba for Use on Genetically Engineered Crops

EPA Pesticide Factsheets

EPA has registered a new dicamba formulation, Extendimax™ with VaporGrip™, specifically designed to have lower volatility, to control weeds in cotton and soybean plants that have been genetically engineered (GE) to resist dicamba.

New Metal Niobate and Silicotitanate Ion Exchangers: Development and Characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexandra Navrotsky; Mary Lou Balmer; Tina M. Nenoff

2003-12-05

This renewal proposal outlines our current progress and future research plans for ion exchangers: novel metal niobate and silicotitanate ion exchangers and their ultimate deployment in the DOE complex. In our original study several forms (including Cs exchanged) of the heat treated Crystalline Silicotitanates (CSTs) were fully characterized by a combination of high temperature synthesis and phase identification, low temperature synthesis and phase identification, and thermodynamics. This renewal proposal is predicated on work completed in our current EMSP program: we have shown preliminary data of a novel class of niobate-based molecular sieves (Na/Nb/M/O, M = transition metals), which show exceptionallymore » high selectivity for divalent cations under extreme conditions (acid solutions, competing cations), in addition to novel silicotitanate phases which are also selective for divalent cations. Furthermore, these materials are easily converted by a high temperature in-situ heat treatment into a refractory ceramic waste form with low cation leachability. The new waste form is a perovskite phase, which is also a major component of Synroc, a titanate ceramic waste form used for sequestration of HLW wastes from reprocessed, spent nuclear fuel. These new niobate ion exchangers also shown orders of magnitude better selectivity for Sr2+ under acid conditions than any other material. The goal of the program is to reduce the costs associated with divalent cation waste removal and disposal, to minimize the risk of contamination to the environment during ion exchanger processing, and to provide DOE with materials for near-term lab-bench stimulant testing, and eventual deployment. The proposed work will provide information on the structure/property relationship between ion exchanger frameworks and selectivity for specific ions, allowing for the eventual ''tuning'' of framework for specific ion exchange needs. To date, DOE sites have become interested in on-site testing of these materials; ongoing discussions and initial experiments are occurring with Dr. Dean Peterman, Idaho National Engineering and Environmental Laboratory (INEEL) (location of the DOE/EM Waste Treatment Focus Area), and Dr. John Harbour, Savannah River Site (SRS). Yet the materials have not been optimized, and further research and development of the novel ion exchangers and testing conditions with simulants are needed. In addition, studies of the ion exchanger composition versus ion selectivity, ion exchange capacity and durability of final waste form are needed. This program will bring together three key institutions to address scientific hurdles of the separation process associated with metal niobate and silicotitanate ion exchangers, in particular for divalent cations (e.g., Sr2+). The program involves a joint effort between researchers at Pacific Northwest National Laboratory, who are leaders in structure/property relations in silicotitanates and in waste form development and performance assessment, Sandia National Laboratories, who discovered and developed crystalline silicotitanate ion exchangers (with Texas A&M and UOP) and also the novel class of divalent metal niobate ion exchangers, and the Thermochemistry Facility at UC Davis, who are world renowned experts in calorimetry and have already performed extensive thermodynamic studies on silicotitanate materials. In addition, Dr. Rodney Ewing of University of Michigan, an expert in radiation effects on materials, and Dr. Robert Roth of the National Institute of Standards and Technology and The Viper Group, a leader in phase equilibria development, will be consultants for radiation and phase studies. The research team will focus on three tasks that will provide both the basic research necessary for the development of highly selective ion exchange materials and also materials for short-term deployment within the DOE complex: (1) Structure/property relationships of a novel class of niobate-based molecular sieves (Na/Nb/M/O, M = transition metals), which show exceptionally high selectivity for divalent cations under extreme conditions (acid solutions, competing cations), (2) the role of ion exchanger structure change (both niobates and silicotitanates) on the exchange capacity (for elements such as Sr and actinide-surrogates) which results from exposure to DOE complex waste simulants, (3) thermodynamic stability of metal niobates and silicotitanate ion exchangers.« less

Hybrid Neural-Network: Genetic Algorithm Technique for Aircraft Engine Performance Diagnostics Developed and Demonstrated

NASA Technical Reports Server (NTRS)

Kobayashi, Takahisa; Simon, Donald L.

2002-01-01

As part of the NASA Aviation Safety Program, a unique model-based diagnostics method that employs neural networks and genetic algorithms for aircraft engine performance diagnostics has been developed and demonstrated at the NASA Glenn Research Center against a nonlinear gas turbine engine model. Neural networks are applied to estimate the internal health condition of the engine, and genetic algorithms are used for sensor fault detection, isolation, and quantification. This hybrid architecture combines the excellent nonlinear estimation capabilities of neural networks with the capability to rank the likelihood of various faults given a specific sensor suite signature. The method requires a significantly smaller data training set than a neural network approach alone does, and it performs the combined engine health monitoring objectives of performance diagnostics and sensor fault detection and isolation in the presence of nominal and degraded engine health conditions.

PRE- AND POST-SYNAPTIC EFFECTS OF MANIPULATING SURFACE CHARGE WITH DIVALENT CATIONS AT THE PHOTORECEPTOR SYNAPSE

PubMed Central

CADETTI, L.; THORESON, W. B.; PICCOLINO, M.

2006-01-01

Persistence of horizontal cell (HC) light responses in extracellular solutions containing low Ca2+ plus divalent cations to block Ca2+ currents (ICa) has been attributed to Ca2+-independent neurotransmission. Using a retinal slice preparation to record both ICa and light responses, we demonstrate that persistence of HC responses in low [Ca2+]o can instead be explained by a paradoxical increase of Ca2+ influx into photoreceptor terminals arising from surface charge-mediated shifts in ICa activation. Consistent with this explanation, application of Zn2+ or Ni2+ caused a hyperpolarizing block of HC light responses that was relieved by lowering [Ca2+]o. The same concentrations of Zn2+ and Ni2+ reduced the amplitude of ICa at the rod dark potential and this reduction was relieved by a hyperpolarizing shift in voltage dependence induced by lowering [Ca2+]o. Block of ICa by Mg2+, which has weak surface charge effects, was not relieved by low [Ca2+]o. Recovery of HC responses in low [Ca2+]o was assisted by enhancement of rod light responses. To bypass light stimulation, OFF bipolar cells were stimulated by steps to −40 mV applied to presynaptic rods during simultaneous paired recordings. Consistent with surface charge theory, the post-synaptic current was inhibited by Zn2+ and this inhibition was relieved by lowering [Ca2+]o. Nominally divalent-free media produced inversion of HC light responses even though rod light responses remained hyperpolarizing; HC response inversion can be explained by surface charge-mediated shifts in ICa. In summary, HC light responses modifications induced by low divalent cation solutions can be explained by effects on photoreceptor light responses and membrane surface charge without necessitating Ca2+-independent neurotransmission. Furthermore, these results suggest that surface charge effects accompanying physiological changing divalent cation levels in the synaptic cleft may provide a means for modulating synaptic output from photoreceptors. PMID:15541900

Divalent carbon(0) chemistry, part 1: Parent compounds.

PubMed

Tonner, Ralf; Frenking, Gernot

2008-01-01

Quantum-chemical calculations with DFT (BP86) and ab initio methods [MP2, SCS-MP2, CCSD(T)] have been carried out for the molecules C(PH(3))(2) (1), C(PMe(3))(2) (2), C(PPh(3))(2) (3), C(PPh(3))(CO) (4), C(CO)(2) (5), C(NHC(H))(2) (6), C(NHC(Me))(2) (7) (Me(2)N)(2)C=C=C(NMe(2))(2) (8), and NHC (9), where NHC=N-heterocyclic carbene and NHC(Me)=N-methyl-substituted NHC. The electronic structure in 1-9 was analyzed with charge- and energy-partitioning methods. The results show that the bonding situations in L(2)C compounds 1-8 can be interpreted in terms of donor-acceptor interactions between closed-shell ligands L and a carbon atom which has two lone-pair orbitals L-->C<--L. This holds particularly for the carbodiphosphoranes 1-3 where L=PR(3), which therefore are classified as divalent carbon(0) compounds. The NBO analysis suggests that the best Lewis structures for the carbodicarbenes 6 and 7 where L is a NHC ligand have C==C==C double bonds as in the tetraaminoallene 8. However, the Lewis structures of 6-8, in which two lone-pair orbitals at the central carbon atom are enforced, have only a slightly higher residual density. Visual inspection of the frontier orbitals of the latter species reveals their pronounced lone-pair character, which suggests that even the quasi-linear tetraaminoallene 8 is a "masked" divalent carbon(0) compound. This explains the very shallow bending potential of 8. The same conclusion is drawn for phosphoranylketene 4 and for carbon suboxide (5), which according to the bonding analysis have hidden double-lone-pair character. The AIM analysis and the EDA calculations support the assignment of carbodiphosphoranes as divalent carbon(0) compounds, while NHC 9 is characterized as a divalent carbon(II) compound. The L-->C((1)D) donor-acceptor bonds are roughly twice as strong as the respective L-->BH(3) bond.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Margrete Meltzer, Helle, E-mail: helle.margrete.meltzer@fhi.no; Lise Brantsaeter, Anne; Borch-Iohnsen, Berit

Low iron (Fe) stores may influence absorption or transport of divalent metals in blood. To obtain more knowledge about such associations, the divalent metal ions cadmium (Cd), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn) and lead (Pb) and parameters of Fe metabolism (serum ferritin, haemoglobin (Hb) and transferrin) were investigated in 448 healthy, menstruating non-smoking women, age 20-55 years (mean 38 years), participating in the Norwegian HUNT 2 study. The study population was stratified for serum ferritin: 257 were iron-depleted (serum ferritin <12 {mu}g/L) and 84 had iron deficiency anaemia (serum ferritin <12 {mu}g/L and Hb<120 g/L). The lowmore » ferritin group had increased blood concentrations of Mn, Co and Cd but normal concentrations of Cu, Zn and Pb. In multiple regression models, ferritin emerged as the main determinant of Mn, Co and Cd (p<0.001), while no significant associations with Cu, Zn and Pb were found. Adjusted r{sup 2} for the models were 0.28, 0.48 and 0.34, respectively. Strong positive associations between blood concentrations of Mn, Co and Cd were observed, also when controlled for their common association with ferritin. Apart from these associations, the models showed no significant interactions between the six divalent metals studied. Very mild anaemia (110{<=}Hb<120 g/L) did not seem to have any effect independent of low ferritin. Approximately 26% of the women with iron deficiency anaemia had high concentrations of all of Mn, Co and Cd as opposed to 2.3% of iron-replete subjects. The results confirm that low serum ferritin may have an impact on body kinetics of certain divalent metal ions, but not all. Only a fraction of women with low iron status exhibited an increased blood concentration of divalent metals, providing indication of complexities in the body's handling of these metals.« less

GMOs in Russia: Research, Society and Legislation

PubMed Central

Korobko, I. V.; Georgiev, P. G.; Skryabin, K. G.; Kirpichnikov, M. P.

2016-01-01

Russian legislation lags behind the rapid developments witnessed in genetic engineering. Only a scientifically based and well-substantiated policy on the place of organisms that are created with the use of genetic engineering technologies and an assessment of the risks associated with them could guarantee that the breakthroughs achieved in modern genetic engineering technologies are effectively put to use in the real economy. A lack of demand for such breakthroughs in the practical field will lead to stagnation in scientific research and to a loss of expertise. PMID:28050262

Arsenic removal in conjunction with lime softening

DOEpatents

Khandaker, Nadim R.; Brady, Patrick V.; Teter, David M.; Krumhansl, James L.

2004-10-12

A method for removing dissolved arsenic from an aqueous medium comprising adding lime to the aqueous medium, and adding one or more sources of divalent metal ions other than calcium and magnesium to the aqueous medium, whereby dissolved arsenic in the aqueous medium is reduced to a lower level than possible if only the step of adding lime were performed. Also a composition of matter for removing dissolved arsenic from an aqueous medium comprising lime and one or more sources of divalent copper and/or zinc metal ions.

Method of microbially producing metal gallate spinel nano-objects, and compositions produced thereby

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duty, Chad E.; Jellison, Jr., Gerald E.; Love, Lonnie J.

A method of forming a metal gallate spinel structure that includes mixing a divalent metal-containing salt and a gallium-containing salt in solution with fermentative or thermophilic bacteria. In the process, the bacteria nucleate metal gallate spinel nano-objects from the divalent metal-containing salt and the gallium-containing salt without requiring reduction of a metal in the solution. The metal gallate spinel structures, as well as light-emitting structures in which they are incorporated, are also described.

[Research progress of genetic engineering on medicinal plants].

PubMed

Teng, Zhong-qiu; Shen, Ye

2015-02-01

The application of genetic engineering technology in modern agriculture shows its outstanding role in dealing with food shortage. Traditional medicinal plant cultivation and collection have also faced with challenges, such as lack of resources, deterioration of environment, germplasm of recession and a series of problems. Genetic engineering can be used to improve the disease resistance, insect resistance, herbicides resistant ability of medicinal plant, also can improve the medicinal plant yield and increase the content of active substances in medicinal plants. Thus, the potent biotechnology can play an important role in protection and large area planting of medicinal plants. In the development of medicinal plant genetic engineering, the safety of transgenic medicinal plants should also be paid attention to. A set of scientific safety evaluation and judgment standard which is suitable for transgenic medicinal plants should be established based on the recognition of the particularity of medicinal plants.

Harnessing biodiesel-producing microbes: from genetic engineering of lipase to metabolic engineering of fatty acid biosynthetic pathway.

PubMed

Yan, Jinyong; Yan, Yunjun; Madzak, Catherine; Han, Bingnan

2017-02-01

Microbial production routes, notably whole-cell lipase-mediated biotransformation and fatty-acids-derived biosynthesis, offer new opportunities for synthesizing biodiesel. They compare favorably to immobilized lipase and chemically catalyzed processes. Genetically modified whole-cell lipase-mediated in vitro route, together with in vivo and ex vivo microbial biosynthesis routes, constitutes emerging and rapidly developing research areas for effective production of biodiesel. This review presents recent advances in customizing microorganisms for producing biodiesel, via genetic engineering of lipases and metabolic engineering (including system regulation) of fatty-acids-derived pathways. Microbial hosts used include Escherichia coli, Saccharomyces cerevisiae, Pichia pastoris and Aspergillus oryzae. These microbial cells can be genetically modified to produce lipases under different forms: intracellularly expressed, secreted or surface-displayed. They can be metabolically redesigned and systematically regulated to obtain balanced biodiesel-producing cells, as highlighted in this study. Such genetically or metabolically modified microbial cells can support not only in vitro biotransformation of various common oil feedstocks to biodiesel, but also de novo biosynthesis of biodiesel from glucose, glycerol or even cellulosic biomass. We believe that the genetically tractable oleaginous yeast Yarrowia lipolytica could be developed to an effective biodiesel-producing microbial cell factory. For this purpose, we propose several engineered pathways, based on lipase and wax ester synthase, in this promising oleaginous host.

Engineering Strategies to Decode and Enhance the Genomes of Coral Symbionts.

PubMed

Levin, Rachel A; Voolstra, Christian R; Agrawal, Shobhit; Steinberg, Peter D; Suggett, David J; van Oppen, Madeleine J H

2017-01-01

Elevated sea surface temperatures from a severe and prolonged El Niño event (2014-2016) fueled by climate change have resulted in mass coral bleaching (loss of dinoflagellate photosymbionts, Symbiodinium spp., from coral tissues) and subsequent coral mortality, devastating reefs worldwide. Genetic variation within and between Symbiodinium species strongly influences the bleaching tolerance of corals, thus recent papers have called for genetic engineering of Symbiodinium to elucidate the genetic basis of bleaching-relevant Symbiodinium traits. However, while Symbiodinium has been intensively studied for over 50 years, genetic transformation of Symbiodinium has seen little success likely due to the large evolutionary divergence between Symbiodinium and other model eukaryotes rendering standard transformation systems incompatible. Here, we integrate the growing wealth of Symbiodinium next-generation sequencing data to design tailored genetic engineering strategies. Specifically, we develop a testable expression construct model that incorporates endogenous Symbiodinium promoters, terminators, and genes of interest, as well as an internal ribosomal entry site from a Symbiodinium virus. Furthermore, we assess the potential for CRISPR/Cas9 genome editing through new analyses of the three currently available Symbiodinium genomes. Finally, we discuss how genetic engineering could be applied to enhance the stress tolerance of Symbiodinium , and in turn, coral reefs.

Non-Genetic Engineering Approaches for Isolating and Generating Novel Yeasts for Industrial Applications

NASA Astrophysics Data System (ADS)

Chambers, P. J.; Bellon, J. R.; Schmidt, S. A.; Varela, C.; Pretorius, I. S.

Generating novel yeast strains for industrial applications should be quite straightforward; after all, research into the genetics, biochemistry and physiology of Baker's Yeast, Saccharomyces cerevisiae, has paved the way for many advances in the modern biological sciences. We probably know more about this humble eukaryote than any other, and it is the most tractable of organisms for manipulation using modern genetic engineering approaches. In many countries, however, there are restrictions on the use of genetically-modified organisms (GMOs), particularly in foods and beverages, and the level of consumer acceptance of GMOs is, at best, variable. Thus, many researchers working with industrial yeasts use genetic engineering techniques primarily as research tools, and strain development continues to rely on non-GM technologies. This chapter explores the non-GM tools and strategies available to such researchers.

Perception of risks and benefits of in vitro fertilization, genetic engineering and biotechnology.

PubMed

Macer, D R

1994-01-01

The use of new biotechnology in medicine has become an everyday experience, but many people still express concern about biotechnology. Concerns are evoked particularly by the phrases genetic engineering and in vitro fertilization (IVF), and these concerns persist despite more than a decade of their use in medicine. Mailed nationwide opinion surveys on attitudes to biotechnology were conducted in Japan, among samples of the public (N = 551), high school biology teachers (N = 228), scientists (N = 555) and nurses (N = 301). People do see more benefits coming from science than harm when balanced against the risks. There were especially mixed perceptions of benefit and risk about IVF and genetic engineering, and a relatively high degree of worry compared to other developments of science and technology. A discussion of assisted reproductive technologies and surrogacy in Japan is also made. The opinions of people in Japan were compared to the results of previous surveys conducted in Japan, and international surveys conducted in Australia, China, Europe, New Zealand, U.K. and U.S.A. Japanese have a very high awareness of biotechnology, 97% saying that they had heard of the word. They also have a high level of awareness of IVF and genetic engineering. Genetic engineering was said to be a worthwhile research area for Japan by 76%, while 58% perceived research on IVF as being worthwhile, however 61% were worried about research on IVF or genetic engineering. Japanese expressed more concern about IVF and genetic engineering than New Zealanders. The major reason cited for rejection of genetic manipulation research in Japan and New Zealand was that it was seen as interfering with nature, playing God or as unethical. The emotions concerning these technologies are complex, and we should avoid using simplistic public opinion data as measures of public perceptions. The level of concern expressed by scientists and teachers in Japan suggest that public education "technology promotion campaigns" will not reduce concern about science and technology. Such concern should be valued as discretion that is basic to increasing the bioethical maturity of a society, rather than being feared.

78 FR 25941 - Stine Seed Farm, Inc.; Extension of a Determination of Nonregulated Status of Corn Genetically...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-03

... Engineered for Herbicide Resistance AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Notice... maize line HCEM485, which has been genetically engineered to be resistant to the herbicide glyphosate...

Notification: Evaluation of Office of Pesticide Programs’ Genetically Engineered Corn Insect Resistance Management

EPA Pesticide Factsheets

Project #OPE-FY15-0055, July 09, 2015. The EPA OIG plans to begin preliminary research on the EPA's ability to manage and prevent increased insect resistance to genetically engineered Bacillus thuringiensis (Bt) corn.

Kinetics studies with fruit bromelain (Ananas comosus) in the presence of cysteine and divalent ions.

PubMed

Kaur, Tajwinder; Kaur, Amandeep; Grewal, Ravneet K

2015-09-01

The kinetics of cysteine and divalent ion modulation viz. Ca(2+), Cu(2+), Hg(2+) of fruit bromelain (EC 3.4.22.33) have been investigated in the present study. Kinetic studies revealed that at pH 4.5, cysteine induced V-type activation of bromelain catalyzed gelatin hydrolysis. At pH 3.5, Ca(2+) inhibited the enzyme noncompetitively, whereas, both K-and V-type activations of bromelain were observed in the presence of 0.5 mM Ca(2+) at pH 4.5 and 7.5. Bromelain was inhibited competitively at 0.6 mM Cu(2+) ions at pH 3.5, which changed to an uncompetitive inhibition at pH 4.5 and 7.5. An un-competitive inhibition of bromelain catalyzed gelatin hydrolysis was observed in the presence of 0.6 mM Hg(2+) at pH 3.5 and 4.5. These findings suggest that divalent ions modulation of fruit bromelain is pH dependent.

Enhancement of superconducting transition temperature in FeSe electric-double-layer transistor with multivalent ionic liquids

NASA Astrophysics Data System (ADS)

Miyakawa, Tomoki; Shiogai, Junichi; Shimizu, Sunao; Matsumoto, Michio; Ito, Yukihiro; Harada, Takayuki; Fujiwara, Kohei; Nojima, Tsutomu; Itoh, Yoshimitsu; Aida, Takuzo; Iwasa, Yoshihiro; Tsukazaki, Atsushi

2018-03-01

We report on an enhancement of the superconducting transition temperature (Tc) of the FeSe-based electric-double-layer transistor (FeSe-EDLT) by applying the multivalent oligomeric ionic liquids (ILs). The IL composed of dimeric cation (divalent IL) enables a large amount of charge accumulation on the surface of the FeSe ultrathin film, resulting in inducing electron-rich conduction even in a rather thick 10 nm FeSe channel. The onset Tc in FeSe-EDLT with the divalent IL is enhanced to be approaching about 50 K at the thin limit, which is about 7 K higher than that in EDLT with conventional monovalent ILs. The enhancement of Tc is a pronounced effect of the application of the divalent IL, in addition to the large capacitance, supposing preferable interface formation of ILs driven by geometric and/or Coulombic effect. The present finding strongly indicates that multivalent ILs are powerful tools for controlling and improving physical properties of materials.

Effect of Divalent Electrolytes on Electroosmotic Flow

NASA Astrophysics Data System (ADS)

Li, Haifeng; Gnanaprakasam, Pradeep

2005-11-01

Electroosmotic flow (EOF) is of importance in micro- and nanofluidic applications. Recent numerical results [Zheng et al. (2003) Electrophoresis 24, 3006] suggest that the addition of even trace amounts of divalent counterions can greatly affect the velocity and electric potential distribution for EOF of a nominally monovalent electrolyte solution, nearly halving the flow rate in 20 nm channels. Scaled experiments were therefore carried out for steady and fully-developed EOF of buffered aqueous mono- and divalent electrolyte mixtures through fused silica microchannels. Nano-particle image velocimetry (nPIV), based upon evanescent-wave illumination of colloidal tracers, was used to obtain velocity data within about 300 nm of the wall. In all cases, the thickness of the electric double layer, defined as the distance from the wall where the velocity and electric potential recover to 99% of their freestream values, is of O(10 nm), or much less than the channel dimension of O(10 μm). The nPIV results are compared with predictions from an asymptotic perturbation analysis.

Thermodynamics of binding interactions between extracellular polymeric substances and heavy metals by isothermal titration microcalorimetry.

PubMed

Yan, Peng; Xia, Jia-Shuai; Chen, You-Peng; Liu, Zhi-Ping; Guo, Jin-Song; Shen, Yu; Zhang, Cheng-Cheng; Wang, Jing

2017-05-01

Extracellular polymeric substances (EPS) play a crucial role in heavy metal bio-adsorption using activated sludge, but the interaction mechanism between heavy metals and EPS remains unclear. Isothermal titration calorimetry was employed to illuminate the mechanism in this study. The results indicate that binding between heavy metals and EPS is spontaneous and driven mainly by enthalpy change. Extracellular proteins in EPS are major participants in the binding process. Environmental conditions have significant impact on the adsorption performance. Divalent and trivalent cations severely impeded the binding of heavy metal ions to EPS. Electrostatic interaction mainly attributed to competition between divalent cations and heavy metal ions; trivalent cations directly competed with heavy metal ions for EPS binding sites. Trivalent cations were more competitive than divalent cations for heavy metal ion binding because they formed complexing bonds. This study facilitates a better understanding about the interaction between heavy metals and EPS in wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation of cation exchanger from lemon and sorption of divalent heavy metals.

PubMed

Arslanoglu, Hasan; Soner Altundogan, H; Tumen, Fikret

2008-05-01

A cation exchanging material was developed from lemon by modifying the pectic-cellulosic substances in the lemon peel by lemon juice having citric acid. For this purpose, chopped lemon removed from seeds and yellow skin was heated in two stages, firstly at 50 degrees C for 24h and subsequently at 120 degrees C for 2h. The material obtained was ground, repeatedly washed with water and dried. Lemon peel and lemon resin obtained were characterized through physicochemical analyses and FTIR spectroscopy. Heavy metal binding performance of this material was determined by removal tests conducted by using 10mM solutions of divalent metals. Experimental results show that the resin prepared from lemon is effective especially for Pb and Cu removals. For a lemon resin dosage of 10 g l(-1), sorption affinity of divalent metal ions is found to be in an order of Pb>Cu>Ni>Fe>Cd>Zn>Co>Mn. Typically, sorption capacities are about 0.87 and 0.43 mmol g(-1) for Pb and Mn, respectively.

Induction of divalent cation permeability by heterologous expression of a voltage sensor domain.

PubMed

Arima, Hiroki; Tsutsui, Hidekazu; Sakamoto, Ayako; Yoshida, Manabu; Okamura, Yasushi

2018-01-06

The voltage sensor domain (VSD) is a protein domain that confers sensitivity to membrane potential in voltage-gated ion channels as well as the voltage-sensing phosphatase. Although VSDs have long been considered to function as regulatory units acting on adjacent effectors, recent studies have revealed the existence of direct ion permeation paths in some mutated VSDs and in the voltage-gated proton channel. In this study, we show that calcium currents are evoked upon membrane hyperpolarization in cells expressing a VSD derived from an ascidian voltage-gated ion channel superfamily. Unlike the previously reported omega-pore in the Shaker K + channel and rNav1.4, mutations are not required. From electrophysiological experiments in heterologous expression systems, we found that the conductance is directly mediated by the VSD itself and is carried by both monovalent and divalent cations. This is the first report of divalent cation permeation through a VSD-like structure. Copyright © 2018 Elsevier B.V. All rights reserved.

The Drosophila divalent metal ion transporter Malvolio is required in dopaminergic neurons for feeding decisions

PubMed Central

Søvik, Eirik; LaMora, Angela; Seehra, Gurpreet; Barron, Andrew B.; Duncan, Jennifer G.; Ben-Shahar, Yehuda

2017-01-01

Members of the Natural resistance-associated macrophage protein (NRAMP) family are evolutionarily-conserved metal ion transporters that play an essential role in regulating intracellular divalent cation homeostasis in both prokaryotes and eukaryotes. Malvolio (Mvl), the sole NRAMP family member in insects, plays a role in food choice behaviors in Drosophila and other species. However, the specific physiological and cellular processes that require the action of Mvl for appropriate feeding decisions remain elusive. Here we demonstrate that normal food choice requires Mvl function specifically in the dopaminergic system, and can be rescued by supplementing food with manganese. Collectively, our data indicate that the action of the Mvl transporter affects food choice behavior via the regulation of dopaminergic innervation of the mushroom bodies, a principle brain region associated with decision making in insects. Our studies suggest that the homeostatic regulation of the intra-neuronal levels of divalent cations plays an important role in the development and function of the dopaminergic system and associated behaviors. PMID:28220999

Reversible changes of canavalin solubility controlled by divalent cation concentration in crude sword bean extract.

PubMed

Nishizawa, Kaho; Arii, Yasuhiro

2016-12-01

Canavalin is a vicilin-class (7S) storage protein found in sword bean (Canavalia gladiata). Our previous report indicated that canavalin is precipitated by the addition of 20 mM MgCl 2 to crude sword bean extract. Here, we examined the solubility changes induced by the addition of Mg 2+ and Ca 2+ at various concentrations. Canavalin tended to be insolubilized at relatively low concentrations of MgCl 2 (< 20 mM) and solubilized at relatively high concentrations (> 20 mM). In addition, canavalin was slightly insolubilized in the presence of NaCl. Overall, the results revealed that solubility changes are reversible and depend on the concentration of divalent cations. Therefore, we suggested a reaction scheme that describes the effects of divalent cations on the solubility of canavalin, which would facilitate the study of its physiological function and the application of canavalin in the food processing industry.

Ligand interaction scan: a general method for engineering ligand-sensitive protein alleles.

PubMed

Erster, Oran; Eisenstein, Miriam; Liscovitch, Mordechai

2007-05-01

The ligand interaction scan (LIScan) method is a general procedure for engineering small molecule ligand-regulated forms of a protein that is complementary to other 'reverse' genetic and chemical-genetic methods for drug-target validation. It involves insertional mutagenesis by a chemical-genetic 'switch', comprising a genetically encoded peptide module that binds with high affinity to a small-molecule ligand. We demonstrated the method with TEM-1 beta-lactamase, using a tetracysteine hexapeptide insert and a biarsenical fluorescein ligand (FlAsH).

Self-Incompatibility in Papaver rhoeas Activates Nonspecific Cation Conductance Permeable to Ca2+ and K+[W

PubMed Central

Wu, Juyou; Wang, Su; Gu, Yuchun; Zhang, Shaoling; Publicover, Stephen J.; Franklin-Tong, Vernonica E.

2011-01-01

Cellular responses rely on signaling. In plant cells, cytosolic free calcium is a major second messenger, and ion channels play a key role in mediating physiological responses. Self-incompatibility (SI) is an important genetically controlled mechanism to prevent self-fertilization. It uses interaction of matching S-determinants from the pistil and pollen to allow “self” recognition, which triggers rejection of incompatible pollen. In Papaver rhoeas, the S-determinants are PrsS and PrpS. PrsS is a small novel cysteine-rich protein; PrpS is a small novel transmembrane protein. Interaction of PrsS with incompatible pollen stimulates S-specific increases in cytosolic free calcium and alterations in the actin cytoskeleton, resulting in programmed cell death in incompatible but not compatible pollen. Here, we have used whole-cell patch clamping of pollen protoplasts to show that PrsS stimulates SI-specific activation of pollen grain plasma membrane conductance in incompatible but not compatible pollen grain protoplasts. The SI-activated conductance does not require voltage activation, but it is voltage sensitive. It is permeable to divalent cations (Ba2+ ≥ Ca2+ > Mg2+) and the monovalent ions K+ and NH4+ and is enhanced at voltages negative to −100 mV. The Ca2+ conductance is blocked by La3+ but not by verapamil; the K+ currents are tetraethylammonium chloride insensitive and do not require Ca2+. We propose that the SI-stimulated conductance may represent a nonspecific cation channel or possibly two conductances, permeable to monovalent and divalent cations. Our data provide insights into signal-response coupling involving a biologically important response. PrsS provides a rare example of a protein triggering alterations in ion channel activity. PMID:21177472

From Precaution to Peril: Public Relations Across Forty Years of Genetic Engineering.

PubMed

Hogan, Andrew J

2016-12-01

The Asilomar conference on genetic engineering in 1975 has long been pointed to by scientists as a model for internal regulation and public engagement. In 2015, the organizers of the International Summit on Human Gene Editing in Washington, DC looked to Asilomar as they sought to address the implications of the new CRISPR gene editing technique. Like at Asilomar, the conveners chose to limit the discussion to a narrow set of potential CRISPR applications, involving inheritable human genome editing. The adoption by scientists in 2015 of an Asilomar-like script for discussing genetic engineering offers historians the opportunity to analyze the adjustments that have been made since 1975, and to identify the blind spots that remain in public engagement. Scientists did take important lessons from the fallout of their limited engagement with public concerns at Asilomar. Nonetheless, the scientific community has continued to overlook some of the longstanding public concerns about genetic engineering, in particular the broad and often covert genetic modification of food products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genetically engineered mouse models for studying inflammatory bowel disease.

PubMed

Mizoguchi, Atsushi; Takeuchi, Takahito; Himuro, Hidetomo; Okada, Toshiyuki; Mizoguchi, Emiko

2016-01-01

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition that is mediated by very complex mechanisms controlled by genetic, immune, and environmental factors. More than 74 kinds of genetically engineered mouse strains have been established since 1993 for studying IBD. Although mouse models cannot fully reflect human IBD, they have provided significant contributions for not only understanding the mechanism, but also developing new therapeutic means for IBD. Indeed, 20 kinds of genetically engineered mouse models carry the susceptibility genes identified in human IBD, and the functions of some other IBD susceptibility genes have also been dissected out using mouse models. Cutting-edge technologies such as cell-specific and inducible knockout systems, which were recently employed to mouse IBD models, have further enhanced the ability of investigators to provide important and unexpected rationales for developing new therapeutic strategies for IBD. In this review article, we briefly introduce 74 kinds of genetically engineered mouse models that spontaneously develop intestinal inflammation. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Science, law, and politics in the Food and Drug Administration's genetically engineered foods policy: FDA's 1992 policy statement.

PubMed

Pelletier, David L

2005-05-01

The US Food and Drug Administration's (FDA's) 1992 policy statement was developed in the context of critical gaps in scientific knowledge concerning the compositional effects of genetic transformation and severe limitations in methods for safety testing. FDA acknowledged that pleiotropy and insertional mutagenesis may cause unintended changes, but it was unknown whether this happens to a greater extent in genetic engineering compared with traditional breeding. Moreover, the agency was not able to identify methods by which producers could screen for unintended allergens and toxicants. Despite these uncertainties, FDA granted genetically engineered foods the presumption of GRAS (Generally Recognized As Safe) and recommended that producers use voluntary consultations before marketing them.

Thermodynamic controls on element partitioning between titanomagnetite and andesitic-dacitic silicate melts

NASA Astrophysics Data System (ADS)

Sievwright, R. H.; Wilkinson, J. J.; O'Neill, H. St. C.; Berry, A. J.

2017-08-01

Titanomagnetite-melt partitioning of Mg, Mn, Al, Ti, Sc, V, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Hf and Ta was investigated experimentally as a function of oxygen fugacity ( fO2) and temperature ( T) in an andesitic-dacitic bulk-chemical compositional range. In these bulk systems, at constant T, there are strong increases in the titanomagnetite-melt partitioning of the divalent cations (Mg2+, Mn2+, Co2+, Ni2+, Zn2+) and Cu2+/Cu+ with increasing fO2 between 0.2 and 3.7 log units above the fayalite-magnetite-quartz buffer. This is attributed to a coupling between magnetite crystallisation and melt composition. Although melt structure has been invoked to explain the patterns of mineral-melt partitioning of divalent cations, a more rigorous justification of magnetite-melt partitioning can be derived from thermodynamic principles, which accounts for much of the supposed influence ascribed to melt structure. The presence of magnetite-rich spinel in equilibrium with melt over a range of fO2 implies a reciprocal relationship between a(Fe2+O) and a(Fe3+O1.5) in the melt. We show that this relationship accounts for the observed dependence of titanomagnetite-melt partitioning of divalent cations with fO2 in magnetite-rich spinel. As a result of this, titanomagnetite-melt partitioning of divalent cations is indirectly sensitive to changes in fO2 in silicic, but less so in mafic bulk systems.

In Vitro Inhibition of Leishmania Attachment to Sandfly Midguts and LL-5 Cells by Divalent Metal Chelators, Anti-gp63 and Phosphoglycans.

PubMed

Soares, Rodrigo Pedro; Altoé, Ellen Cristina Félix; Ennes-Vidal, Vítor; da Costa, Simone M; Rangel, Elizabeth Ferreira; de Souza, Nataly Araújo; da Silva, Vanderlei Campos; Volf, Petr; d'Avila-Levy, Claudia Masini

2017-07-01

Leishmania braziliensis and Leishmania infantum are the causative agents of cutaneous and visceral leishmaniasis, respectively. Several aspects of the vector-parasite interaction involving gp63 and phosphoglycans have been individually assayed in different studies. However, their role under the same experimental conditions was not studied yet. Here, the roles of divalent metal chelators, anti-gp63 antibodies and purified type I phosphoglycans (PGs) were evaluated during in vitro parasite attachment to the midgut of the vector. Parasites were treated with divalent metal chelators or anti-gp63 antibodies prior to the interaction with Lutzomyia longipalpis/Lutzomyia intermedia midguts or sand fly LL-5 cells. In vitro binding system was used to examine the role of PG and gp63 in parallel. Treatment with divalent metal chelators reduced Le. infantum adhesion to the Lu. longipalpis midguts. The most effective compound (Phen) inhibited the binding in both vectors. Similar results were observed in the interaction between both Leishmania species and the cell line LL-5. Finally, parallel experiments using anti-gp63-treated parasites and PG-incubated midguts demonstrated that both approaches substantially inhibited attachment in the natural parasite-vector pairs Le. infantum/Lu. longipalpis and Le. braziliensis/Lu. intermedia. Our results suggest that gp63 and/or PG are involved in parasite attachment to the midgut of these important vectors. Copyright © 2017 Elsevier GmbH. All rights reserved.

Charge Shielding of PIP2 by Cations Regulates Enzyme Activity of Phospholipase C

PubMed Central

Seo, Jong Bae; Jung, Seung-Ryoung; Huang, Weigang; Zhang, Qisheng; Koh, Duk-Su

2015-01-01

Hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) of the plasma membrane by phospholipase C (PLC) generates two critical second messengers, inositol-1,4,5-trisphosphate and diacylglycerol. For the enzymatic reaction, PIP2 binds to positively charged amino acids in the pleckstrin homology domain of PLC. Here we tested the hypothesis that positively charged divalent and multivalent cations accumulate around the negatively charged PIP2, a process called electrostatic charge shielding, and therefore inhibit electrostatic PIP2-PLC interaction. This charge shielding of PIP2 was measured quantitatively with an in vitro enzyme assay using WH-15, a PIP2 analog, and various recombinant PLC proteins (β1, γ1, and δ1). Reduction of PLC activity by divalent cations, polyamines, and neomycin was well described by a theoretical model considering accumulation of cations around PIP2 via their electrostatic interaction and chemical binding. Finally, the charge shielding of PIP2 was also observed in live cells. Perfusion of the cations into cells via patch clamp pipette reduced PIP2 hydrolysis by PLC as triggered by M1 muscarinic receptors with a potency order of Mg2+ < spermine4+ < neomycin6+. Accumulation of divalent cations into cells through divalent-permeable TRPM7 channel had the same effect. Altogether our results suggest that Mg2+ and polyamines modulate the activity of PLCs by controlling the amount of free PIP2 available for the enzymes and that highly charged biomolecules can be inactivated by counterions electrostatically. PMID:26658739

Electrochemical Formation of Divalent Samarium Cation and Its Characteristics in LiCl-KCl Melt.

PubMed

Bae, Sang-Eun; Jung, Tae Sub; Cho, Young-Hwan; Kim, Jong-Yun; Kwak, Kyungwon; Park, Tae-Hong

2018-06-28

The electrochemical reduction of trivalent samarium in a LiCl-KCl eutectic melt produced highly stable divalent samarium, whose electrochemical properties and electronic structure in the molten salt were investigated using cyclic voltammetry, UV-vis absorption spectroscopy, laser-induced emission spectroscopy, and density functional theory (DFT) calculations. Diffusion coefficients of Sm 2+ and Sm 3+ were electrochemically measured to be 0.92 × 10 -5 and 1.10 × 10 -5 cm 2 /s, respectively, and the standard apparent potential of the Sm 2+/3+ couple was estimated to be -0.82 V vs Ag|Ag + at 450 °C. The spectroelectrochemical study demonstrated that the redox behavior of the samarium cations obeys the Nernst equation ( E°' = -0.83 V, n = 1) and the trivalent samarium cation was successfully converted to the divalent cation having characteristic absorption bands at 380 and 530 nm with molar absorptivity values of 1470 and 810 M -1 cm -1 , respectively. Density function theory calculations for the divalent samarium complex revealed that the absorption signals originated from the 4f 6 to 4f 5 5d 1 transitions. Additionally, laser-induced emission measurements for the Sm cations in the LiCl-KCl matrix showed that the Sm 3+ ion in the LiCl-KCl melt at 450 °C emitted an orange color of fluorescence, whereas a red colored emission was observed from the Sm 2+ ion in the solidified LCl-KCl salt at room temperature.

Treatment of drinking water residuals: comparing sedimentation and dissolved air flotation performance with optimal cation ratios.

PubMed

Bourgeois, J C; Walsh, M E; Gagnon, G A

2004-03-01

Spent filter backwash water (SFBW) and clarifier sludge generally comprise the majority of the waste residual volume generated and in relative terms, these can be collectively referred to as combined filter backwash water (CFBW). CFBW is essentially a low-solids wastewater with metal hydroxide flocs that are typically light and slow to settle. This study evaluates the impact of adding calcium and magnesium carbonates to CFBW in terms of assessing the impacts on the sedimentation and DAF separation processes. Representative CFBW samples were collected from two surface water treatment plants (WTP): Lake Major WTP (Dartmouth, Nova Scotia, Canada) and Victoria Park WTP (Truro, Nova Scotia, Canada). Bench-scale results indicated that improvements in the CFBW settled water quality could be achieved through the addition of the divalent cations, thereby adjusting the monovalent to divalent (M:D) ratios of the wastewater. In general, the DAF process required slightly higher M:D ratios than the sedimentation process. The optimum M:D ratios for DAF and sedimentation were determined to be 1:1 and 0.33:1, respectively. It was concluded that the optimisation of the cation balance between monovalent cations (e.g., Na(+), K(+)) and added divalent cations (i.e., Ca(2+), Mg(2+)) aided in the settling mechanism through charge neutralisation-precipitation. The increase in divalent cation concentrations within the waste residual stream promoted destabilisation of the negatively charged colour molecules within the CFBW, thereby causing the colloidal content to become more hydrophobic.

Charge Shielding of PIP2 by Cations Regulates Enzyme Activity of Phospholipase C.

PubMed

Seo, Jong Bae; Jung, Seung-Ryoung; Huang, Weigang; Zhang, Qisheng; Koh, Duk-Su

2015-01-01

Hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) of the plasma membrane by phospholipase C (PLC) generates two critical second messengers, inositol-1,4,5-trisphosphate and diacylglycerol. For the enzymatic reaction, PIP2 binds to positively charged amino acids in the pleckstrin homology domain of PLC. Here we tested the hypothesis that positively charged divalent and multivalent cations accumulate around the negatively charged PIP2, a process called electrostatic charge shielding, and therefore inhibit electrostatic PIP2-PLC interaction. This charge shielding of PIP2 was measured quantitatively with an in vitro enzyme assay using WH-15, a PIP2 analog, and various recombinant PLC proteins (β1, γ1, and δ1). Reduction of PLC activity by divalent cations, polyamines, and neomycin was well described by a theoretical model considering accumulation of cations around PIP2 via their electrostatic interaction and chemical binding. Finally, the charge shielding of PIP2 was also observed in live cells. Perfusion of the cations into cells via patch clamp pipette reduced PIP2 hydrolysis by PLC as triggered by M1 muscarinic receptors with a potency order of Mg2+ < spermine4+ < neomycin6+. Accumulation of divalent cations into cells through divalent-permeable TRPM7 channel had the same effect. Altogether our results suggest that Mg2+ and polyamines modulate the activity of PLCs by controlling the amount of free PIP2 available for the enzymes and that highly charged biomolecules can be inactivated by counterions electrostatically.

Binding symmetry of extracellular divalent cations to conduction pore studied using tandem dimers of a CNG channel.

PubMed

Kwon, Ryuk-Jun; Ha, Tal Soo; Kim, Wonjae; Park, Chul-Seung

2002-11-08

Cyclic nucleotide-gated (CNG) channels are composed of the tetramer of alpha-subunit alone or alpha- and beta-subunits. The alpha-subunits of these channels have a conserved glutamate (Glu) residue within the pore-forming region and the residue determines the selectivity as well as the affinity for the extracellular divalent cations. Using the high-affinity mutant (E363D) of bovine retinal CNG channel in which the Glu at position 363 was replaced to Asp, we constructed tandem dimers and investigated the binding characteristics of divalent cations to the site. The gating and permeation characteristics of individual homomeric tandem dimers are indistinguishable to those of homo-tetramers formed by parental monomers. The heteromeric tandem dimers showed the binding affinity for Sr(2+) identical to the geometric mean of the affinities for two parent channels, indicating the energy additive and thus the simultaneous interaction. On the other hand, the binding affinity for Mg(2+) followed the harmonic mean of those parent channels indicating that Mg(2+) interacts more strongly with the subunit bearing Asp residue at the position. Thus the results strongly suggest that the Glu363 residues in the CNG channel pore be flexible enough to adapt different binding symmetries for different divalent cations. Moreover, the simultaneous interaction between the four Glu residues and Sr(2+) provides an important structural constraint to the CNG channel outer vestibule of unknown structure.

Notification: Evaluation of EPA's Management of Resistance Issues Related to Herbicide Tolerant Genetically Engineered Crops

EPA Pesticide Factsheets

Project #OPE-FY16-0023, March 25, 2016. The EPA OIG plans to begin preliminary research to assess the EPA's management and oversight of resistance issues related to herbicide tolerant genetically engineered crops.

The establishment of genetically engineered canola populations in the U.S.

EPA Science Inventory

Concerns regarding the commercial release of genetically engineered (GE) crops include naturalization, introgression to sexually compatible relatives and the transfer of beneficial traits to native and weedy species through hybridization. To date there have been few documented re...

Expanding and reprogramming the genetic code.

PubMed

Chin, Jason W

2017-10-04

Nature uses a limited, conservative set of amino acids to synthesize proteins. The ability to genetically encode an expanded set of building blocks with new chemical and physical properties is transforming the study, manipulation and evolution of proteins, and is enabling diverse applications, including approaches to probe, image and control protein function, and to precisely engineer therapeutics. Underpinning this transformation are strategies to engineer and rewire translation. Emerging strategies aim to reprogram the genetic code so that noncanonical biopolymers can be synthesized and evolved, and to test the limits of our ability to engineer the translational machinery and systematically recode genomes.

Recent advances in genetic modification systems for Actinobacteria.

PubMed

Deng, Yu; Zhang, Xi; Zhang, Xiaojuan

2017-03-01

Actinobacteria are extremely important to human health, agriculture, and forests. Because of the vast differences of the characteristics of Actinobacteria, a lot of genetic tools have been developed for efficiently manipulating the genetics. Although there are a lot of successful examples of engineering Actinobacteria, they are still more difficult to be genetically manipulated than other model microorganisms such as Saccharomyces cerevisiae, Escherichia coli, and Bacillus subtilis etc. due to the diverse genomics and biochemical machinery. Here, we review the methods to introduce heterologous DNA into Actinobacteria and the available genetic modification tools. The trends and problems existing in engineering Actinobacteria are also covered.

Genetically Engineered Pig Models for Human Diseases

PubMed Central

Prather, Randall S.; Lorson, Monique; Ross, Jason W.; Whyte, Jeffrey J.; Walters, Eric

2015-01-01

Although pigs are used widely as models of human disease, their utility as models has been enhanced by genetic engineering. Initially, transgenes were added randomly to the genome, but with the application of homologous recombination, zinc finger nucleases, and transcription activator-like effector nuclease (TALEN) technologies, now most any genetic change that can be envisioned can be completed. To date these genetic modifications have resulted in animals that have the potential to provide new insights into human diseases for which a good animal model did not exist previously. These new animal models should provide the preclinical data for treatments that are developed for diseases such as Alzheimer's disease, cystic fibrosis, retinitis pigmentosa, spinal muscular atrophy, diabetes, and organ failure. These new models will help to uncover aspects and treatments of these diseases that were otherwise unattainable. The focus of this review is to describe genetically engineered pigs that have resulted in models of human diseases. PMID:25387017

Synthetic alienation of microbial organisms by using genetic code engineering: Why and how?

PubMed

Kubyshkin, Vladimir; Budisa, Nediljko

2017-08-01

The main goal of synthetic biology (SB) is the creation of biodiversity applicable for biotechnological needs, while xenobiology (XB) aims to expand the framework of natural chemistries with the non-natural building blocks in living cells to accomplish artificial biodiversity. Protein and proteome engineering, which overcome limitation of the canonical amino acid repertoire of 20 (+2) prescribed by the genetic code by using non-canonic amino acids (ncAAs), is one of the main focuses of XB research. Ideally, estranging the genetic code from its current form via systematic introduction of ncAAs should enable the development of bio-containment mechanisms in synthetic cells potentially endowing them with a "genetic firewall" i.e. orthogonality which prevents genetic information transfer to natural systems. Despite rapid progress over the past two decades, it is not yet possible to completely alienate an organism that would use and maintain different genetic code associations permanently. In order to engineer robust bio-contained life forms, the chemical logic behind the amino acid repertoire establishment should be considered. Starting from recent proposal of Hartman and Smith about the genetic code establishment in the RNA world, here the authors mapped possible biotechnological invasion points for engineering of bio-contained synthetic cells equipped with non-canonical functionalities. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Induction of atherosclerosis in mice and hamsters without germline genetic engineering.

PubMed

Bjørklund, Martin Maeng; Hollensen, Anne Kruse; Hagensen, Mette Kallestrup; Dagnaes-Hansen, Frederik; Christoffersen, Christina; Mikkelsen, Jacob Giehm; Bentzon, Jacob Fog

2014-05-23

Atherosclerosis can be achieved in animals by germline genetic engineering, leading to hypercholesterolemia, but such models are constrained to few species and strains, and they are difficult to combine with other powerful techniques involving genetic manipulation or variation. To develop a method for induction of atherosclerosis without germline genetic engineering. Recombinant adeno-associated viral vectors were engineered to encode gain-of-function proprotein convertase subtilisin/kexin type 9 mutants, and mice were given a single intravenous vector injection followed by high-fat diet feeding. Plasma proprotein convertase subtilisin/kexin type 9 and total cholesterol increased rapidly and were maintained at high levels, and after 12 weeks, mice had atherosclerotic lesions in the aorta. Histology of the aortic root showed progression of lesions to the fibroatheromatous stage. To demonstrate the applicability of this method for rapid analysis of the atherosclerosis susceptibility of a mouse strain and for providing temporal control over disease induction, we demonstrated the accelerated atherosclerosis of mature diabetic Akita mice. Furthermore, the versatility of this approach for creating atherosclerosis models also in nonmurine species was demonstrated by inducing hypercholesterolemia and early atherosclerosis in Golden Syrian hamsters. Single injections of proprotein convertase subtilisin/kexin type 9-encoding recombinant adeno-associated viral vectors are a rapid and versatile method to induce atherosclerosis in animals. This method should prove useful for experiments that are high-throughput or involve genetic techniques, strains, or species that do not combine well with current genetically engineered models. © 2014 American Heart Association, Inc.

Genetic engineering for skeletal regenerative medicine.

PubMed

Gersbach, Charles A; Phillips, Jennifer E; García, Andrés J

2007-01-01

The clinical challenges of skeletal regenerative medicine have motivated significant advances in cellular and tissue engineering in recent years. In particular, advances in molecular biology have provided the tools necessary for the design of gene-based strategies for skeletal tissue repair. Consequently, genetic engineering has emerged as a promising method to address the need for sustained and robust cellular differentiation and extracellular matrix production. As a result, gene therapy has been established as a conventional approach to enhance cellular activities for skeletal tissue repair. Recent literature clearly demonstrates that genetic engineering is a principal factor in constructing effective methods for tissue engineering approaches to bone, cartilage, and connective tissue regeneration. This review highlights this literature, including advances in the development of efficacious gene carriers, novel cell sources, successful delivery strategies, and optimal target genes. The current status of the field and the challenges impeding the clinical realization of these approaches are also discussed.

Genetically Engineering Entomopathogenic Fungi.

PubMed

Zhao, H; Lovett, B; Fang, W

2016-01-01

Entomopathogenic fungi have been developed as environmentally friendly alternatives to chemical insecticides in biocontrol programs for agricultural pests and vectors of disease. However, mycoinsecticides currently have a small market share due to low virulence and inconsistencies in their performance. Genetic engineering has made it possible to significantly improve the virulence of fungi and their tolerance to adverse conditions. Virulence enhancement has been achieved by engineering fungi to express insect proteins and insecticidal proteins/peptides from insect predators and other insect pathogens, or by overexpressing the pathogen's own genes. Importantly, protein engineering can be used to mix and match functional domains from diverse genes sourced from entomopathogenic fungi and other organisms, producing insecticidal proteins with novel characteristics. Fungal tolerance to abiotic stresses, especially UV radiation, has been greatly improved by introducing into entomopathogens a photoreactivation system from an archaean and pigment synthesis pathways from nonentomopathogenic fungi. Conversely, gene knockout strategies have produced strains with reduced ecological fitness as recipients for genetic engineering to improve virulence; the resulting strains are hypervirulent, but will not persist in the environment. Coupled with their natural insect specificity, safety concerns can also be mitigated by using safe effector proteins with selection marker genes removed after transformation. With the increasing public concern over the continued use of synthetic chemical insecticides and growing public acceptance of genetically modified organisms, new types of biological insecticides produced by genetic engineering offer a range of environmentally friendly options for cost-effective control of insect pests. Copyright © 2016 Elsevier Inc. All rights reserved.

CRISPR: a Versatile Tool for Both Forward and Reverse Genetics Research

PubMed Central

Gurumurthy, Channabasavaiah B.; Grati, M'hamed; Ohtsuka, Masato; Schilit, Samantha L.P.; Quadros, Rolen M.; Liu, Xue Zhong

2016-01-01

Human genetics research employs the two opposing approaches of forward and reverse genetics. While forward genetics identifies and links a mutation to an observed disease etiology, reverse genetics induces mutations in model organisms to study their role in disease. In most cases, causality for mutations identified by forward genetics is confirmed by reverse genetics through the development of genetically engineered animal models and an assessment of whether the model can recapitulate the disease. While many technological advances have helped improve these approaches, some gaps still remain. CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated) system, which has emerged as a revolutionary genetic engineering tool, holds great promise for closing such gaps. By combining the benefits of forward and reverse genetics, it has dramatically expedited human genetics research. We provide a perspective on the power of CRISPR-based forward and reverse genetics tools in human genetics and discuss its applications using some disease examples. PMID:27384229

Conjugated polymer zwitterions and solar cells comprising conjugated polymer zwitterions

DOEpatents

Emrick, Todd; Russell, Thomas; Page, Zachariah; Liu, Yao

2018-06-05

A conjugated polymer zwitterion includes repeating units having structure (I), (II), or a combination thereof ##STR00001## wherein Ar is independently at each occurrence a divalent substituted or unsubstituted C_3-30 arylene or heteroarylene group; L is independently at each occurrence a divalent C_1-16 alkylene group, C_6-30arylene or heteroarylene group, or alkylene oxide group; and R¹ is independently at each occurrence a zwitterion. A polymer solar cell including the conjugated polymer zwitterion is also disclosed.

Water-Rock Interactions in the Peridotite Aquifer of the Oman-UAE Ophiolite: Strontium Isotopic Ratio and Geochemical Evolution of Groundwater

NASA Astrophysics Data System (ADS)

Bompard, Nicolas; Matter, Juerg; Teagle, Damon

2016-04-01

The peridotite aquifer in Wadi Tayin, Sultanate of Oman, is a perfect example of natural carbonation of ultramafic rocks. In situ mineral carbonation is considered the most safest and permanent option of CO2 Capture and Sequestration (CCS). However, the process itself is yet to be characterised and a better understanding of the mechanisms involved in natural mineral carbonation is needed before geo-engineering it. We used the 87Sr/86Sr system to follow the water-rock interactions along the groundwater flowpath in the peridotite aquifer and to determine the sources of divalent cations (Mg2+, Ca2+) required for mineral carbonation. The Sr-isotope data of groundwater show that the aquifer rocks are the main source for divalent cations (Mg2+, Ca2+ and Sr2+) and secondary carbonates are their main sink. The groundwater 87Sr/86Sr ratio evolves with its pH: from 87Sr/86Sr = 0.7087 (n=3) to 0.7082 (n=8) between pH 7 and 8, and from 0.7086 (n=6) at pH 9 to 0.07075 (n=9) at pH 11. This evolution seems to support a two-step model for the water-rock interactions in the peridotite aquifer. From pH 7 to 8, secondary Ca-carbonate precipitation buffers the pH rise resulting from peridotite serpentinisation. From pH 9 to 11, peridotite serpentinisation drives the pH to alkaline condition. The change from a Mg-rich to a Ca-rich groundwater at pH 9 seems to confirm the two-step model.

Probing the roles of Ca(2+) and Mg(2+) in humic acids-induced ultrafiltration membrane fouling using an integrated approach.

PubMed

Wang, Long-Fei; He, Dong-Qin; Chen, Wei; Yu, Han-Qing

2015-09-15

Membrane fouling induced by natural organic matter (NOM) negatively affects the performance of ultrafiltration (UF) technology in producing drinking water. Divalent cation is found to be an important factor that affects the NOM-induced membrane fouling process. In this work, attenuated total reflection-Fourier transformation infrared spectroscopy (ATR-FTIR) coupled with quartz crystal microbalance (QCM), assisted by isothermal titration calorimetry (ITC), is used to explore the contribution of Mg(2+) and Ca(2+), the two abundant divalent cations in natural water, to the UF membrane fouling caused by humic acid (HA) at a molecular level. The results show that Ca(2+) exhibited superior performance in accelerating fouling compared to Mg(2+). The hydrophobic polyethersulfone (PES) membrane exhibited greater complexation with HA in the presence of Mg(2+) and Ca(2+), compared to the hydrophilic cellulose membrane, as evidenced by the more intense polysaccharide C-O, aromatic C=C and carboxylic C=O bands in the FTIR spectra. The QCM and ITC measurements provide quantitative evidence to support that Ca(2+) was more effective than Mg(2+) in binding with HA and accumulating foulants on the membrane surfaces. The higher charge neutralization capacity and more favorable binding ability of Ca(2+) were found to be responsible for its greater contribution to the NOM-induced membrane fouling than Mg(2+). This work offers a new insight into the mechanism of cation-mediated NOM-induced membrane fouling process, and demonstrates that such an integrated ATR-FTIR/QCM/ITC approach could be a useful tool to explore other complicated interaction processes in natural and engineered environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Template engineered biopotent macrocyclic complexes involving furan moiety: Molecular modeling and molecular docking

NASA Astrophysics Data System (ADS)

Rathi, Parveen; Singh, D. P.

2015-08-01

Bioactive cobalt(II), nickel(II), copper(II) and zinc(II) complexes of octaazamacrocycle, 19, 20-dioxa-2,3,5,6,11,12,14,15-octaazatricyclo[14.2.1.1]icosa-1,6,8,10,15,17-hexaene-4,13-dithione, derived from furan-2,5-dione and thiocarbonohydrazide in the mole ratio 2:2:1 have been engineered via template methodology. The synthesized metal complexes have also been structurally characterized in the light of various physicochemical techniques and evaluated for antimicrobial and antioxidant activities. All these studies point toward the formation of divalent macrocyclic complexes possessing distorted octahedral geometry and having significant antimicrobial and antioxidant properties as compared to the starting precursors. Virtual screening of a representative complex was done through docking to the binding site of COX-2 to evaluate the anti-inflammatory activity of the series. Non-electrolytic nature of the complexes has been predicted on the basis of low value of molar conductivity in DMSO. All the complexes were having notable activities against pathogenic microbes as compared to precursors-thiocarbonohydrazide and furan-2,5-dione however, the complex 5, [Ni (C10H8N8O2S2) (NO3)2], shows the best antimicrobial activity.

Silk Materials Functionalized via Genetic Engineering for Biomedical Applications.

PubMed

Deptuch, Tomasz; Dams-Kozlowska, Hanna

2017-12-12

The great mechanical properties, biocompatibility and biodegradability of silk-based materials make them applicable to the biomedical field. Genetic engineering enables the construction of synthetic equivalents of natural silks. Knowledge about the relationship between the structure and function of silk proteins enables the design of bioengineered silks that can serve as the foundation of new biomaterials. Furthermore, in order to better address the needs of modern biomedicine, genetic engineering can be used to obtain silk-based materials with new functionalities. Sequences encoding new peptides or domains can be added to the sequences encoding the silk proteins. The expression of one cDNA fragment indicates that each silk molecule is related to a functional fragment. This review summarizes the proposed genetic functionalization of silk-based materials that can be potentially useful for biomedical applications.

Genetic Engineering and Crop Production.

ERIC Educational Resources Information Center

Jones, Helen C.; Frost, S.

1991-01-01

With a spotlight upon current agricultural difficulties and environmental dilemmas, this paper considers both the extant and potential applications of genetic engineering with respect to crop production. The nonagricultural factors most likely to sway the impact of this emergent technology upon future crop production are illustrated. (JJK)

A CAL Program to Teach the Basic Principles of Genetic Engineering--A Change from the Traditional Approach.

ERIC Educational Resources Information Center

Dewhurst, D. G.; And Others

1989-01-01

An interactive computer-assisted learning program written for the BBC microcomputer to teach the basic principles of genetic engineering is described. Discussed are the hardware requirements software, use of the program, and assessment. (Author/CW)

IMPROVING PLANT GENETIC ENGINEERING BY MANIPULATING THE HOST. (R829479C001)

EPA Science Inventory

Agrobacterium-mediated transformation is a major technique for the genetic engineering of plants. However, there are many economically important crop and tree species that remain highly recalcitrant to Agrobacterium infection. Although attempts have been made to ...

A portable expression resource for engineering cross-species genetic circuits and pathways

PubMed Central

Kushwaha, Manish; Salis, Howard M.

2015-01-01

Genetic circuits and metabolic pathways can be reengineered to allow organisms to process signals and manufacture useful chemicals. However, their functions currently rely on organism-specific regulatory parts, fragmenting synthetic biology and metabolic engineering into host-specific domains. To unify efforts, here we have engineered a cross-species expression resource that enables circuits and pathways to reuse the same genetic parts, while functioning similarly across diverse organisms. Our engineered system combines mixed feedback control loops and cross-species translation signals to autonomously self-regulate expression of an orthogonal polymerase without host-specific promoters, achieving nontoxic and tuneable gene expression in diverse Gram-positive and Gram-negative bacteria. Combining 50 characterized system variants with mechanistic modelling, we show how the cross-species expression resource's dynamics, capacity and toxicity are controlled by the control loops' architecture and feedback strengths. We also demonstrate one application of the resource by reusing the same genetic parts to express a biosynthesis pathway in both model and non-model hosts. PMID:26184393

Genetically Engineering Bacillus subtilis with a Heat-Resistant Arsenite Methyltransferase for Bioremediation of Arsenic-Contaminated Organic Waste

PubMed Central

Huang, Ke; Chen, Chuan; Shen, Qirong; Rosen, Barry P.

2015-01-01

Organic manures may contain high levels of arsenic (As) due to the use of As-containing growth-promoting substances in animal feed. To develop a bioremediation strategy to remove As from organic waste, Bacillus subtilis 168, a bacterial strain which can grow at high temperature but is unable to methylate and volatilize As, was genetically engineered to express the arsenite S-adenosylmethionine methyltransferase gene (CmarsM) from the thermophilic alga Cyanidioschyzon merolae. The genetically engineered B. subtilis 168 converted most of the inorganic As in the medium into dimethylarsenate and trimethylarsine oxide within 48 h and volatized substantial amounts of dimethylarsine and trimethylarsine. The rate of As methylation and volatilization increased with temperature from 37 to 50°C. When inoculated into an As-contaminated organic manure composted at 50°C, the modified strain significantly enhanced As volatilization. This study provides a proof of concept of using genetically engineered microorganisms for bioremediation of As-contaminated organic waste during composting. PMID:26187966

Pressure for a select committee on human embryo research and genetic engineering.

PubMed

McKie, David

1985-11-02

By a commanding majority of almost five million votes, this year's Labour Party conference agreed that Labour Members of Parliament should not be permitted to let their consciences decide their votes on "issues affecting the reproductive rights of women." The targets for this censure were the 44 Labour MPs who backed Enoch Powell's bill to outlaw experiments on embryos. Conservative supporters of the Powell bill are countering their defeat by advocating a Parliamentary select committee to examine "matters of human embryo research and human genetic engineering." McKie comments that they are thus shifting emphasis from "fertility," which has public support, to genetic engineering, which generates fear.

Physiological significance of ghrelin revealed by studies using genetically engineered mouse models with modifications in the ghrelin system.

PubMed

Ariyasu, Hiroyuki; Akamizu, Takashi

2015-01-01

Ghrelin, an endogenous ligand for the growth hormone (GH) secretagogue receptor (GHS-R or ghrelin receptor), is a 28-amino acid acylated peptide mainly produced in the stomach. The pharmacological administration of ghrelin is known to exert diverse effects, such as stimulating GH secretion, promoting food intake, and increasing adiposity. In recent years, genetically engineered mouse models have provided important insights into the physiology of various hormones. In this review, we discuss current knowledge regarding the physiological significance of ghrelin on the basis of studies using genetically engineered mouse models with modifications in the ghrelin system.

Crop Genetics: The Seeds of Revolution.

ERIC Educational Resources Information Center

DeYoung, H. Garrett

1983-01-01

Current research in plant genetics is described. Benefits of this research (which includes genetic engineering applications) will include reduction/elimination of crop diseases, assurance of genetic stability, and the creation of new crop varieties. (JN)

Synthetic Biology and the U.S. Biotechnology Regulatory System: Challenges and Options

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, Sarah R.; Rodemeyer, Michael; Garfinkel, Michele S.

Synthetic Biology and the U.S. Biotechnology Regulatory System: Challenges and Options Sarah R. Carter, Ph.D., J. Craig Venter Institute; Michael Rodemeyer, J.D., University of Virginia; Michele S. Garfinkel, Ph.D., EMBO; Robert M. Friedman, Ph.D., J. Craig Venter Institute In recent years, a range of genetic engineering techniques referred to as “synthetic biology” has significantly expanded the tool kit available to scientists and engineers, providing them with far greater capabilities to engineer organisms than previous techniques allowed. The field of synthetic biology includes the relatively new ability to synthesize long pieces of DNA from chemicals, as well as improved methods formore » genetic manipulation and design of genetic pathways to achieve more precise control of biological systems. These advances will help usher in a new generation of genetically engineered microbes, plants, and animals. The JCVI Policy Center team, along with researchers at the University of Virginia and EMBO, examined how well the current U.S. regulatory system for genetically engineered products will handle the near-term introduction of organisms engineered using synthetic biology. In particular, the focus was on those organisms intended to be used or grown directly in the environment, outside of a contained facility. The study concludes that the U.S. regulatory agencies have adequate legal authority to address most, but not all, potential environmental, health and safety concerns posed by these organisms. Such near-term products are likely to represent incremental changes rather than a marked departure from previous genetically engineered organisms. However, the study also identified two key challenges for the regulatory system, which are detailed in the report. First, USDA’s authority over genetically engineered plants depends on the use of an older engineering technique that is no longer necessary for many applications. The shift to synthetic biology and other newer genetic engineering techniques will leave many engineered plants without any pre-market regulatory review. Second, the number and diversity of engineered microbes for commercial use will increase in the near future, challenging EPA’s resources, expertise, and perhaps authority to regulate them. For each of these challenges, the report sets out a series of options, including an analysis of the advantages and disadvantages of each option from a variety of perspectives, for policy makers to consider. Policy responses will depend on the trade-offs chosen among competing considerations. This report, funded by the Department of Energy with additional funds from the Alfred P. Sloan Foundation, is the result of a two-year process that included interviews, commissioned background papers, discussions, and two workshops that sought input from a wide range of experts, including U.S. federal agency regulators, legal and science policy experts, representatives from the biotechnology indus¬try, and non-governmental organiza¬tions. This cross-section of views informed this report, but the conclusions are solely those of the authors. An Executive Summary, full Report, and background papers are available at: http://www.jcvi.org/cms/research/projects/synthetic-biology-and-the-us-biotechnology-regulatory-system/overview/« less

Paper Genetic Engineering.

ERIC Educational Resources Information Center

MacClintic, Scott D.; Nelson, Genevieve M.

Bacterial transformation is a commonly used technique in genetic engineering that involves transferring a gene of interest into a bacterial host so that the bacteria can be used to produce large quantities of the gene product. Although several kits are available for performing bacterial transformation in the classroom, students do not always…

Signature pathway expression of xylose utilization in the genetically engineered industrial yeast Saccharomyces cerevisiae

USDA-ARS?s Scientific Manuscript database

Background: The limited xylose utilizing ability of native Saccharomyces cerevisiae has been a major obstacle for efficient cellulosic ethanol production from lignocellulosic materials. Haploid laboratory strains of S. cerevisiae are commonly used for genetic engineering to enable its xylose utiliza...

University Students' Knowledge and Attitude about Genetic Engineering

ERIC Educational Resources Information Center

Bal, Senol; Samanci, Nilay Keskin; Bozkurt, Orçun

2007-01-01

Genetic engineering and biotechnology made possible of gene transfer without discriminating microorganism, plant, animal or human. However, although these scientific techniques have benefits, they cause arguments because of their ethical and social impacts. The arguments about ethical ad social impacts of biotechnology made clear that not only…

Gene flow in genetically engineered perennial grasses: Lessons for modification of dedicated bioenergy crops

EPA Science Inventory

The potential ecological consequences of the commercialization of genetically engineered (GD) crops have been the subject of intense debate, particularly when the GE crops are perennial and capable of outcrossing to wild relatives. The essential ecological impact issues for engi...

78 FR 1522 - Semiannual Regulatory Agenda, Fall 2012

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-08

..., interstate movement, and environmental release of certain genetically engineered organisms and update the... of Organisms 0579-AC31 and Products Altered or Produced Through Genetic Engineering. 139 Importation..., Riverdale, MD 20737-1231, Phone: 301 851-2286. RIN: 0579-AC05 138. Introduction of Organisms and Products...

Stabilizing effect of citrate buffer on the photolysis of riboflavin in aqueous solution

PubMed Central

Ahmad, Iqbal; Sheraz, Muhammad Ali; Ahmed, Sofia; Kazi, Sadia Hafeez; Mirza, Tania; Aminuddin, Mohammad

2011-01-01

In the present investigation the photolysis of riboflavin (RF) in the presence of citrate species at pH 4.0–7.0 has been studied. A specific multicomponent spectrophotometric method has been used to assay RF in the presence of photoproducts during the reactions. The overall first-order rate constants (kobs) for the photolysis of RF range from 0.42 to 1.08×10–2 min−1 in the region. The values of kobs have been found to decrease with an increase in citrate concentration indicating an inhibitory effect of these species on the rate of reaction. The second-order rate constants for the interaction of RF with total citrate species causing inhibition range from 1.79 to 5.65×10–3 M−1 min−1 at pH 4.0–7.0. The log k–pH profiles for the reactions at 0.2–1.0 M citrate concentration show a gradual decrease in kobs and the value at 1.0 M is more than half compared to that of k0, i.e., in the absence of buffer, at pH 5.0. Divalent citrate ions cause a decrease in RF fluorescence due to the quenching of the excited singlet state resulting in a decrease in the rate of reaction and consequently leading to the stabilization of RF solutions. The greater quenching of fluorescence at pH 4.0 compared to that of 7.0 is in accordance with the greater concentration of divalent citrate ions (99.6%) at that pH. The trivalent citrate ions exert a greater inhibitory effect on the rate of RF photolysis compared to that of the divalent citrate ions probably as a result of excited triplet state quenching. The values of second-order rate constants for the interaction of divalent and trivalent citrate ions are 0.44×10–2 and 1.06×10–3 M–1 min–1, respectively, indicating that the trivalent ions exert a greater stabilizing effect, compared to the divalent ions, on RF solutions. PMID:25755977

Interaction studies of human prion protein (HuPrP109-111: methionine-lysine-histidine) tripeptide model with transition metal cations.

PubMed

Pitchumani Violet Mary, C; Shankar, R; Vijayakumar, S; Kolandaivel, P

2016-09-01

In the present study, the coordination bonds between the Methionine-Lysine-Histidine (Ac-MKH-NHMe) tripeptide model associated with the fifth metal binding site, which triggers the β-sheet formation of human prion protein and the divalent metal cations such as Mn(2+), Cu(2+) and Zn(2+) were studied using B3LYP and M052X levels of theory with LANL2DZ basis set. For each transition divalent metal cation, three different coordination modes (4N, 3NO, and 2NSO) were analyzed. The present result reveals that overall structural parameters of MKH model tripeptide are altered due to the interaction of divalent metal cations. Among these three coordination modes, the 4N-M(2)(+) and 4N2O-Mn(2+) complexes are found to have the larger interaction energy, MIA and deformation energies. The triply deprotonated coordination mode of the Ac-MKH-NHMe tripeptide transfers more amount of charge to the divalent metal cations than the dually and singly deprotonated complexes. Furthermore, the atoms in molecules (AIM) topological analysis confirm that, the interaction between the metal cations Mn(2+), Cu(2+) and Zn(2+) and Ac-MKH-NHMe tripeptide are electrostatic dominant and the coordination modes with triply deprotonation states possess larger electron density at their BCP corresponding to their coordination bonds. The electrostatic potential difference maps of the most stable 4N-M(2+) (M(2+)=Cu(2+) and Zn(2+)) and 4N2O-Mn(2+) reveals that, as the ionic radii of the metal ion increases, the delocalization charges localized on the metal cations are found to be decreased. The Infra-red stretching frequencies of NH, CH, and CH2 groups of each coordination complexes are observed with shift in their stretching frequencies. From these observations we conclude that, the transition divalent metal cations binding in 4N coordination mode will induce more conformational changes of the Prion protein. Copyright © 2016 Elsevier Inc. All rights reserved.

Genetically-engineered pig-to-baboon liver xenotransplantation: histopathology of xenografts and native organs.

PubMed

Ekser, Burcin; Klein, Edwin; He, Jing; Stolz, Donna B; Echeverri, Gabriel J; Long, Cassandra; Lin, Chih Che; Ezzelarab, Mohamed; Hara, Hidetaka; Veroux, Massimiliano; Ayares, David; Cooper, David K C; Gridelli, Bruno

2012-01-01

Orthotopic liver transplantation was carried out in baboons using wild-type (WT, n = 1) or genetically-engineered pigs (α1,3-galactosyltransferase gene-knockout, GTKO), n = 1; GTKO pigs transgenic for human CD46, n = 7) and a clinically-acceptable immunosuppressive regimen. Biopsies were obtained from the WT pig liver pre-Tx and at 30 min, 1, 2, 3, 4 and 5 h post-transplantation. Biopsies of genetically-engineered livers were obtained pre-Tx, 2 h after reperfusion and at necropsy (4-7 days after transplantation). Tissues were examined by light, confocal, and electron microscopy. All major native organs were also examined. The WT pig liver underwent hyperacute rejection. After genetically-engineered pig liver transplantation, hyperacute rejection did not occur. Survival was limited to 4-7 days due to repeated spontaneous bleeding in the liver and native organs (as a result of profound thrombocytopenia) which necessitated euthanasia. At 2 h, graft histology was largely normal. At necropsy, genetically-engineered pig livers showed hemorrhagic necrosis, platelet aggregation, platelet-fibrin thrombi, monocyte/macrophage margination mainly in liver sinusoids, and vascular endothelial cell hypertrophy, confirmed by confocal and electron microscopy. Immunohistochemistry showed minimal deposition of IgM, and almost absence of IgG, C3, C4d, C5b-9, and of a cellular infiltrate, suggesting that neither antibody- nor cell-mediated rejection played a major role.

History and future of genetically engineered food animal regulation: an open request.

PubMed

Wells, Kevin D

2016-06-01

Modern biotechnology resulted from of a series of incremental improvements in the understanding of DNA and the enzymes that nature evolved to manipulate it. As the potential impact of genetic engineering became apparent, scientists began the process of trying to identify the potential unintended consequences. Restrictions to recombinant DNA experimentation were at first self-imposed. Collaborative efforts between scientists and lawyers formalized an initial set of guidelines. These guidelines have been used to promulgate regulations around world. However, the initial guidelines were only intended as a starting point and were motivated by a specific set of concerns. As new data became available, the guidelines and regulations should have been adapted to the new knowledge. Instead, other social drivers drove the development of regulations. For most species and most applications, the framework that was established has slowly allowed some products to reach the market. However, genetically engineered livestock that are intended for food have been left in a regulatory state of limbo. To date, no genetically engineered food animal is available in the marketplace. A short history and a U.S.-based genetic engineer's perspective are presented. In addition, a request to regulatory agencies is presented for consideration as regulation continues to evolve. Regulators appear to have shown preference for the slow, random progression of evolution over the efficiency of intentional design.

European Science Notes, Volume 40, Number 5.

DTIC Science & Technology

1986-05-01

microbiology , genetic engineering, and genetic engineering of plants is reviewed. Environmental Sciences -: ") EUROMECH 201-Aplications of the Jchanics...Si"co lo with the research activities at the Lab- Soil Microbiology oratory of Genetics at the University of It is now well documented that a Ghent...spec- tesi , for succeeding in running dedica- tacular observation of SFPM up to four " ted research under incredibly hard Stokes orders in a 300-m

Multisite Ion Model in Concentrated Solutions of Divalent Cations (MgCl2 and CaCl2): Osmotic Pressure Calculations

PubMed Central

2015-01-01

Accurate force field parameters for ions are essential for meaningful simulation studies of proteins and nucleic acids. Currently accepted models of ions, especially for divalent ions, do not necessarily reproduce the right physiological behavior of Ca2+ and Mg2+ ions. Saxena and Sept (J. Chem. Theor. Comput.2013, 9, 3538–3542) described a model, called the multisite-ion model, where instead of treating the ions as an isolated sphere, the charge was split into multiple sites with partial charge. This model provided accurate inner shell coordination of the ion with biomolecules and predicted better free energies for proteins and nucleic acids. Here, we expand and refine the multisite model to describe the behavior of divalent ions in concentrated MgCl2 and CaCl2 electrolyte solutions, eliminating the unusual ion–ion pairing and clustering of ions which occurred in the original model. We calibrate and improve the parameters of the multisite model by matching the osmotic pressure of concentrated solutions of MgCl2 to the experimental values and then use these parameters to test the behavior of CaCl2 solutions. We find that the concentrated solutions of both divalent ions exhibit the experimentally observed behavior with correct osmotic pressure, the presence of solvent separated ion pairs instead of direct ion pairs, and no aggregation of ions. The improved multisite model for (Mg2+ and Ca2+) can be used in classical simulations of biomolecules at physiologically relevant salt concentrations. PMID:25482831

EmrE, a multidrug transporter from Escherichia coli, transports monovalent and divalent substrates with the same stoichiometry.

PubMed

Rotem, Dvir; Schuldiner, Shimon

2004-11-19

Multidrug transporters recognize and transport substrates with apparently little common structural features. At times these substrates are neutral, negatively, or positively charged, and only limited information is available as to how these proteins deal with the energetic consequences of transport of substrates with different charges. Multidrug transporters and drug-specific efflux systems are responsible for clinically significant resistance to chemotherapeutic agents in pathogenic bacteria, fungi, parasites, and human cancer cells. Understanding how these efflux systems handle different substrates may also have practical implications in the development of strategies to overcome the resistance mechanisms mediated by these proteins. Here, we compare transport of monovalent and divalent substrates by EmrE, a multidrug transporter from Escherichia coli, in intact cells and in proteoliposomes reconstituted with the purified protein. The results demonstrated that whereas the transport of monovalent substrates involves charge movement (i.e. electrogenic), the transport of divalent substrate does not (i.e. electroneutral). Together with previous results, these findings suggest that an EmrE dimer exchanges two protons per substrate molecule during each transport cycle. In intact cells, under conditions where the only driving force is the electrical potential, EmrE confers resistance to monovalent substrates but not to divalent ones. In the presence of proton gradients, resistance to both types of substrates is detected. The finding that under some conditions EmrE does not remove certain types of drugs points out the importance of an in-depth understanding of mechanisms of action of multidrug transporters to devise strategies for coping with the problem of multidrug resistance.

Survival differences among freeze-dried genetically engineered and wild-type bacteria.

PubMed Central

Israeli, E; Shaffer, B T; Hoyt, J A; Lighthart, B; Ganio, L M

1993-01-01

Because the death mechanisms of freeze-dried and air-dried bacteria are thought to be similar, freeze-drying was used to investigate the survival differences between potentially airborne genetically engineered microorganisms and their wild types. To this end, engineered strains of Escherichia coli and Pseudomonas syringae were freeze-dried and exposed to air, visible light, or both. The death rates of all engineered strains were significantly higher than those of their parental strains. Light and air exposure were found to increase the death rates of all strains. Application of death rate models to freeze-dried engineered bacteria to be released into the environment is discussed. PMID:8434925

Robustness of magnetic and electric domains against charge carrier doping in multiferroic hexagonal ErMnO 3

DOE PAGES

Hassanpour, E.; Wegmayr, V.; Schaab, J.; ...

2016-04-12

We investigate the effect of chemical doping on the electric and magnetic domain pattern in multiferroic hexagonal ErMnO 3 . Hole- and electron doping are achieved through the growth of Er 1-x Ca x MnO 3 and Er 1-x Zr x MnO 3 single crystals, which allows for a controlled introduction of divalent and tetravalent ions, respectively. Using conductance measurements, piezoresponse force microscopy and nonlinear optics we study doping-related variations in the electronic transport and image the corrsponding ferroelectric and antiferromagnetic domains. We find that moderate doping levels allow for adjusting the electronic conduction properties of ErMnO 3 without destroyingmore » its characteristic domain patterns. Our findings demonstrate the feasibility of chemical doping for nonperturbative property-engineering of intrinsic domain states in this important class of multiferroics.« less

Genetically engineered peptides for inorganics: study of an unconstrained bacterial display technology and bulk aluminum alloy.

PubMed

Adams, Bryn L; Finch, Amethist S; Hurley, Margaret M; Sarkes, Deborah A; Stratis-Cullum, Dimitra N

2013-09-06

The first-ever peptide biomaterial discovery using an unconstrained engineered bacterial display technology is reported. Using this approach, we have developed genetically engineered peptide binders for a bulk aluminum alloy and use molecular dynamics simulation of peptide conformational fluctuations to demonstrate sequence-dependent, structure-function relationships for metal and metal oxide interactions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Genetic Engineering--A Lesson on Bioethics for the Classroom.

ERIC Educational Resources Information Center

Armstrong, Kerri; Weber, Kurt

1991-01-01

A unit designed to cover the topic of genetic engineering and its ethical considerations is presented. Students are expected to learn the material while using a debate format. A list of objectives for the unit, the debate format, and the results from an opinion questionnaire are described. (KR)

Development and deregulation of the plum pox virus resistant transgenic plum 'HoneySweet'

USDA-ARS?s Scientific Manuscript database

We have demonstrated that genetic engineering can be an important source of high level and durable resistance against Plum pox virus (PPV). We have shown, through a number of field studies, the environmental safety of this genetically engineered plum. Nevertheless, the utilization of this demonstr...

78 FR 51706 - Bayer CropScience LP; Determination of Nonregulated Status of Soybean Genetically Engineered for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-21

... Soybean Genetically Engineered for Herbicide Resistance AGENCY: Animal and Plant Health Inspection Service... for resistance to the herbicides glyphosate and isoxaflutole, is no longer considered a regulated... for resistance to the herbicides glyphosate and isoxaflutole. The petition states that this soybean is...

77 FR 41358 - Bayer CropScience LP; Availability of Petition, Plant Pest Risk Assessment, and Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... for Determination of Nonregulated Status of Soybean Genetically Engineered for Herbicide Tolerance... genetically engineered for resistance to the herbicides glyphosate and isoxaflutole. The petition has been... herbicides glyphosate and isoxaflutole. The petition states that this soybean is unlikely to pose a plant...

Can Man Control His Biological Evolution? A Symposium on Genetic Engineering. Artificial Synthesis of New Life Forms

ERIC Educational Resources Information Center

Danielli, James F.

1972-01-01

Research in manipulation of genetic inheritance opens new vistas. Biologically-styled industrial synthesis is better in many respects than chemical engineering practices now in use. An approach for improving hereditary characters in living organisms without considering social implications is unwise. (PS)

78 FR 13302 - Syngenta Biotechnology, Inc.; Determination of Nonregulated Status of Corn Genetically Engineered...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-27

...] Syngenta Biotechnology, Inc.; Determination of Nonregulated Status of Corn Genetically Engineered for... are advising the public of our determination that a corn line developed by the Syngenta Biotechnology... evaluation of data submitted by Syngenta Biotechnology, Inc., in its petition for a determination of...

The Structure of the Metal Transporter Tp34 and its Affinity for Divalent Metal Ions

NASA Astrophysics Data System (ADS)

Knutsen, Gregory; Deka, Ranjit; Brautigam, Chad; Tomchick, Diana; Machius, Mischa; Norgard, Michael

2007-10-01

Tp34 is periplasmic membrane protein of the nonculitvatable spirochete Treponema pallidum, the pathogen of syphillis. It was proposed that Tp34 is a divalent metal transporter, but the identity of the preferred metal ion(s) was unclear. In this study we investigated the ability of divalent metal ions to induce rTp34 dimerization using hydrodynamic techniques and determine the crystal structure of metal bound forms. Using analytical ultracentrifugation sedimentation velocity experiments, we determined that cobalt is superior to nickel at inducing the dimerization of rTp34. rTp34 was crystallized and selected crystals were incubated at a pH 7.5 with CuSO4 and NiSO4. Diffraction experiments were conducted and the processed electron density maps showed that copper was bound to the major metal binding site as well as to three additional minor binding sites. By contrast nickel was only bound to the major metal binding site in one monomer and to three additional minor sites. These results along with previous findings support evidence of Tp34 being involved with metal transport and/or iron utilization.

Mechanistic insights into allosteric regulation of the A 2A adenosine G protein-coupled receptor by physiological cations

DOE PAGES

Ye, Libin; Neale, Chris Andrew; Sljoka, Adnan; ...

2018-04-10

Cations play key roles in regulating G-protein-coupled receptors (GPCRs), although their mechanisms are poorly understood. Here, 19F NMR is used to delineate the effects of cations on functional states of the adenosine A 2A GPCR. While Na + reinforces an inactive ensemble and a partial-agonist stabilized state, Ca 2+ and Mg 2+ shift the equilibrium toward active states. Positive allosteric effects of divalent cations are more pronounced with agonist and a G-protein-derived peptide. In cell membranes, divalent cations enhance both the affinity and fraction of the high affinity agonist-bound state. Molecular dynamics simulations suggest high concentrations of divalent cations bridgemore » specific extracellular acidic residues, bringing TM5 and TM6 together at the extracellular surface and allosterically driving open the G-protein-binding cleft as shown by rigidity-transmission allostery theory. Lastly, an understanding of cation allostery should enable the design of allosteric agents and enhance our understanding of GPCR regulation in the cellular milieu.« less

Selective digestion of Ba2+/Ca2+ alginate gel microdroplets for single-cell handling

NASA Astrophysics Data System (ADS)

Odaka, Masao; Hattori, Akihiro; Matsuura, Kenji; Yasuda, Kenji

2018-06-01

Cells encapsuled by polymer microdroplets are an effective platform for the identification and separation of individual cells for single-cell-based analysis. However, a key challenge is to maintain and release the captured cells in the microdroplets selectively, nondestructively, and noninvasively. We developed a simple method of encapsulating cells in alginate microdroplets having different digestion characteristics. Cells were diluted with an alginate polymer of sol state and encapsulated into microdroplets with Ba2+ and Ca2+ by a spray method. When a chelating buffer was applied, alginate gel microdroplets were digested according to the difference in chelating efficiency of linkage-divalent cations; hence, two types of alginate microdroplets were formed. Moreover, we examined the capability of the alginate gel to exchange linkage-divalent cations and found that both Ca2+ exchange in Ba-alginate microdroplets and Ba2+ exchange in Ca-alginate microdroplets occurred. These results indicate that the potential applications of a mixture of alginate microdroplets with different divalent cations control the selective digestion of microdroplets to improve the high-throughput, high-content microdroplet-based separation, analysis, or storage of single cells.

Evolution in vitro of an RNA enzyme with altered metal dependence

NASA Technical Reports Server (NTRS)

Lehman, N.; Joyce, G. F.

1993-01-01

The Tetrahymena group I ribozyme catalyses a sequence-specific phosphodiester cleavage reaction on an external RNA oligonucleotide substrate in the presence of a divalent metal cation cofactor. This reaction proceeds readily with either Mg2+ or Mn2+, but no detectable reaction has been reported when other divalent cations are used as the sole cofactor. Cations such as Ca2+, Sr2+ and Ba2+ can stabilize the correct folded conformation of the ribozyme, thereby partially alleviating the Mg2+ or Mn2+ requirement. But catalysis by the ribozyme involves coordination of either Mg2+ or Mn2+ at the active site, resulting in an overall requirement for one of these two cations. Here we use an in vitro evolution process to obtain variants of the Tetrahymena ribozyme that are capable of cleaving an RNA substrate in reaction mixtures containing Ca2+ as the divalent cation. These findings extend the range of different chemical environments available to RNA enzymes and illustrate the power of in vitro evolution in generating macromolecular catalysts with desired properties.

Mechanisms of Divalent Metal Toxicity in Affective Disorders

PubMed Central

Menon, Archita Venugopal; Chang, JuOae; Kim, Jonghan

2016-01-01

Metals are required for proper brain development and play an important role in a number of neurobiological functions. The Divalent Metal Transporter 1 (DMT1) is a major metal transporter involved in the absorption and metabolism of several essential metals like iron and manganese. However, non-essential divalent metals are also transported through this transporter. Therefore, altered expression of DMT1 can modify the absorption of toxic metals and metal-induced toxicity. An accumulating body of evidence has suggested that increased metal stores in the brain are associated with elevated oxidative stress mediated by the ability of metals to catalyze redox reactions, resulting in abnormal neurobehavioral function and the progression of neurodegenerative diseases. Metal overload has also been implicated in impaired emotional behavior, although the underlying mechanisms are not well understood with limited information. The current review focuses on psychiatric dysfunction associated with imbalanced metabolism of metals that are transported by DMT1. The investigations with respect to the toxic effects of metal overload on behavior and their underlying mechanisms of toxicity could provide several new therapeutic targets to treat metal-associated affective disorders. PMID:26551072

Uptake of photosensitizers by bacteria is influenced by the presence of cations

NASA Astrophysics Data System (ADS)

Kishen, A.; George, S.

2007-05-01

This investigation studies the influence of cations on photosensitizer uptake by Enterococcus faecalis (gram positive) and Actinobacillus actinomycetemcomitans (gram negative). Methods- The uptake of Methylene blue (MB) and Indocyanine Green (ICG), by bacteria were studied under the influence of divalent cations (CaCl II & MgCl II) and EDTA. Further, E. faecalis cells subjected to trypsinisation and calcium channel blocker (verapamil) were also analysed for MB and ICG uptake inorder to understand the mechanism of photosensitizer uptake. Results- Uptake of ICG was enhanced in the presence of divalent cations in E. faecalis and A. actinomycetemcomitans. Treating cells with EDTA had no significant effect on the photosensitizer uptake, although the highest concentration tested showed an enhancement of uptake. In contrast to ICG, MB showed a decreased uptake by bacterial cells on subjecting them to divalent cations and EDTA. Calcium channel blocker had no significant inhibitory effect on photosensitizers uptake. However, trypsin treatment resulted in significant reduction of ICG uptake. The result suggested that ICG uptake by bacteria is mediated through specific transporter protein while MB is associated with the outer surface structures of bacterial cells.

Ion adsorption-induced wetting transition in oil-water-mineral systems.

PubMed

Mugele, Frieder; Bera, Bijoyendra; Cavalli, Andrea; Siretanu, Igor; Maestro, Armando; Duits, Michel; Cohen-Stuart, Martien; van den Ende, Dirk; Stocker, Isabella; Collins, Ian

2015-05-27

The relative wettability of oil and water on solid surfaces is generally governed by a complex competition of molecular interaction forces acting in such three-phase systems. Herein, we experimentally demonstrate how the adsorption of in nature abundant divalent Ca(2+) cations to solid-liquid interfaces induces a macroscopic wetting transition from finite contact angles (≈ 10°) with to near-zero contact angles without divalent cations. We developed a quantitative model based on DLVO theory to demonstrate that this transition, which is observed on model clay surfaces, mica, but not on silica surfaces nor for monovalent K(+) and Na(+) cations is driven by charge reversal of the solid-liquid interface. Small amounts of a polar hydrocarbon, stearic acid, added to the ambient decane synergistically enhance the effect and lead to water contact angles up to 70° in the presence of Ca(2+). Our results imply that it is the removal of divalent cations that makes reservoir rocks more hydrophilic, suggesting a generalizable strategy to control wettability and an explanation for the success of so-called low salinity water flooding, a recent enhanced oil recovery technology.

Mechanistic insights into allosteric regulation of the A 2A adenosine G protein-coupled receptor by physiological cations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Libin; Neale, Chris Andrew; Sljoka, Adnan

Cations play key roles in regulating G-protein-coupled receptors (GPCRs), although their mechanisms are poorly understood. Here, 19F NMR is used to delineate the effects of cations on functional states of the adenosine A 2A GPCR. While Na + reinforces an inactive ensemble and a partial-agonist stabilized state, Ca 2+ and Mg 2+ shift the equilibrium toward active states. Positive allosteric effects of divalent cations are more pronounced with agonist and a G-protein-derived peptide. In cell membranes, divalent cations enhance both the affinity and fraction of the high affinity agonist-bound state. Molecular dynamics simulations suggest high concentrations of divalent cations bridgemore » specific extracellular acidic residues, bringing TM5 and TM6 together at the extracellular surface and allosterically driving open the G-protein-binding cleft as shown by rigidity-transmission allostery theory. Lastly, an understanding of cation allostery should enable the design of allosteric agents and enhance our understanding of GPCR regulation in the cellular milieu.« less

Synthesis of β-galactosylamides as ligands of the peanut lectin. Insights into the recognition process.

PubMed

Cano, María Emilia; Varela, Oscar; García-Moreno, María Isabel; García Fernández, José Manuel; Kovensky, José; Uhrig, María Laura

2017-04-18

The synthesis of mono and divalent β-galactosylamides linked to a hydroxylated chain having a C2 symmetry axis derived from l-tartaric anhydride is reported. Reference compounds devoid of hydroxyl groups in the linker were also prepared from β-galactosylamine and succinic anhydride. After functionalization with an alkynyl residue, the resulting building blocks were grafted onto different azide-equipped scaffolds through the copper catalyzed azide-alkyne cycloaddition. Thus, a family of structurally related mono and divalent β-N-galactopyranosylamides was obtained and fully characterized. The binding affinities of the ligands towards the model lectin PNA were measured by the enzyme-linked lectin assay (ELLA). The IC 50 values were significantly higher than that of galactose but the presence of hydroxyl groups in the aglycone chain improved lectin recognition. Docking and molecular dynamics experiments were in accordance with the hypothesis that a hydroxyl group properly disposed in the linker could mimic the Glc O3 in the recognition process. On the other hand, divalent presentation of the ligands led to lectin affinity enhancements. Copyright © 2017 Elsevier Ltd. All rights reserved.

The regulation of integrin function by divalent cations

PubMed Central

Zhang, Kun; Chen, JianFeng

2012-01-01

Integrins are a family of α/β heterodimeric adhesion metalloprotein receptors and their functions are highly dependent on and regulated by different divalent cations. Recently advanced studies have revolutionized our perception of integrin metal ion-binding sites and their specific functions. Ligand binding to integrins is bridged by a divalent cation bound at the MIDAS motif on top of either α I domain in I domain-containing integrins or β I domain in α I domain-less integrins. The MIDAS motif in β I domain is flanked by ADMIDAS and SyMBS, the other two crucial metal ion binding sites playing pivotal roles in the regulation of integrin affinity and bidirectional signaling across the plasma membrane. The β-propeller domain of α subunit contains three or four β-hairpin loop-like Ca2+-binding motifs that have essential roles in integrin biogenesis. The function of another Ca2+-binding motif located at the genu of α subunit remains elusive. Here, we provide an overview of the integrin metal ion-binding sites and discuss their roles in the regulation of integrin functions. PMID:22647937

Silk Materials Functionalized via Genetic Engineering for Biomedical Applications

PubMed Central

Deptuch, Tomasz

2017-01-01

The great mechanical properties, biocompatibility and biodegradability of silk-based materials make them applicable to the biomedical field. Genetic engineering enables the construction of synthetic equivalents of natural silks. Knowledge about the relationship between the structure and function of silk proteins enables the design of bioengineered silks that can serve as the foundation of new biomaterials. Furthermore, in order to better address the needs of modern biomedicine, genetic engineering can be used to obtain silk-based materials with new functionalities. Sequences encoding new peptides or domains can be added to the sequences encoding the silk proteins. The expression of one cDNA fragment indicates that each silk molecule is related to a functional fragment. This review summarizes the proposed genetic functionalization of silk-based materials that can be potentially useful for biomedical applications. PMID:29231863

Engineering species-like barriers to sexual reproduction.

PubMed

Maselko, Maciej; Heinsch, Stephen C; Chacón, Jeremy M; Harcombe, William R; Smanski, Michael J

2017-10-12

Controlling the exchange of genetic information between sexually reproducing populations has applications in agriculture, eradication of disease vectors, control of invasive species, and the safe study of emerging biotechnology applications. Here we introduce an approach to engineer a genetic barrier to sexual reproduction between otherwise compatible populations. Programmable transcription factors drive lethal gene expression in hybrid offspring following undesired mating events. As a proof of concept, we target the ACT1 promoter of the model organism Saccharomyces cerevisiae using a dCas9-based transcriptional activator. Lethal overexpression of actin results from mating this engineered strain with a strain containing the wild-type ACT1 promoter.Genetic isolation of a genetically modified organism represents a useful strategy for biocontainment. Here the authors use dCas9-VP64-driven gene expression to construct a 'species-like' barrier to reproduction between two otherwise compatible populations.

Genetically engineered multivalent single chain antibody constructs for cancer therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Surinder Batra, Ph D

2006-02-27

Current therapeutic approaches against the advanced stages of human solid tumors are palliative rather than curative. Many modalities, including, surgery, radiation, and chemotherapy, either alone or in combination have met with only modest success for advanced metastatic cancers. Radioimmunotherapy (RIT) combines the specificity of monoclonal antibodies with cytotxic effects of radioisotopes. It is the smart way of delivering radiation to the known and occult metastatic cancer cells and is independent of drug toxicity and/or hormone resistance. The tumor associated glycoprotein-72 (TAG-72) containing the unique disaccharide sialyl-Tn, is highly expressed in majority of adenocarcinomas, including carcinomas of the prostate, breast, ovaries,more » pancreas and colon (80-90%) compared to undetectable expression in normal tissues. Monoclonal antibody CC49, reactive with TAG-72, after conjugation to potent gamma- and beta-emitting radionuclides, has been useful in selective systemic radiolocalization of disease and therapy of primary and metastatic tumor sites. However, limited therapeutic responses were observed in patients. Limited success of antibody based delivery of radioisotopes can be attributed to several factors including undesirable pharmacokinetics, poor tumor uptake and high immunogenicity of intact antibodies (IgGs). The primary factors contributing towards the failure of RIT include: 1) longer serum half-lives of the intact IgG molecules resulting in the radiotoxicity, 2) generation of human antibodies against murine antibodies (HAMA) that limits the frequency of dose administration, 3) poor diffusion rates of intact IgG due to the large size and 4) high interstitial fluid pressures (IFP) encountered in solid tumors. The major goal of our multidisciplinary project was to develop specific novel radiopharmaceuticals, with desired pharmacokinetics, for the diagnosis and therapy of solid tumors. To overcome the low uptake of radioactivity by tumors and to increase its tumor: normal tissue ratio for improved therapeutic index, we engineered a variety antibody constructs. These constructs were evaluated using novel approaches like special radionuclides, pretargeting and optimization. Due to the smaller size, the engineered antibody molecules should penetrate better throughout a tumor mass, with less dose heterogeneity, than is the case with intact IgG. Multivalent scFvs with an appropriate radionuclide, therefore, hold promising prospects for cancer therapy and clinical imaging in MAb-based radiopharmaceuticals. In addition, the human anti-mouse antibodies (HAMA) responses in patients against antibody-based therapy are usually directed against the immunoglobulin constant regions; however, anti-idiotypic responses can also be detected. The HAMA responses reduce the efficacy of treatment by removing the circulating antibody molecules, fragments, and possibly scFvs by altering the pharmacokinetic properties of the antibody. HAMA responses against divalent IgG, divalent Ig fragments, and possibly multimeric scFvs could cause immune complex formation with hypersensitivity or allergic reactions that could be harmful to patients. The use of small molecules, such as scFvs (monomeric as well as multimeric), with their shorter biological half-lives and the lack of the constant regions and humanized variable (binding regions) performed in our studies should reduce the development of HAMA. The generation of humanized and fully human scFvs should further reduce the development of HAMA. Specific accomplishments on the project are the production of large amounts of recombinant antibodies as they are required in large amounts for cancer diagnosis and therapy. A variety of single-chain Fv (scFv) constructs were engineered for the desired pharmacokinetic properties. Tetrameric and dimeric scFvs showed a two-fold advantage: (1) there was a considerable gain in avidity as compared to smaller fragments, and (2) the biological half-life was more compatible with RIT and RIS requirements. For RIT, delivery for sc(Fv)2 and [sc(Fv)2]2 in a fractionated schedule clearly presented a therapeutic advantage over single administration. The treatment group receiving tetravalent scFv showed a statistically significant prolonged survival with both single and fractionated administrations. 99mTc-labeled multivalent scFvs show good tumor targeting characteristics with high radiolocalization indices (tumor:background ratio). Macroautoradiography performed at 6 and 16 h post administration of labeled 99mTc-sc(Fv)2 and 99mTc-[sc(Fv)2] clearly detected the tumors in mice. Huamnaized scFs showed decreased immunogencity with patient sera.« less

A Tet-on and Cre-loxP Based Genetic Engineering System for Convenient Recycling of Selection Markers in Penicillium oxalicum

PubMed Central

Jiang, Baojie; Zhang, Ruiqin; Feng, Dan; Wang, Fangzhong; Liu, Kuimei; Jiang, Yi; Niu, Kangle; Yuan, Quanquan; Wang, Mingyu; Wang, Hailong; Zhang, Youming; Fang, Xu

2016-01-01

The lack of selective markers has been a key problem preventing multistep genetic engineering in filamentous fungi, particularly for industrial species such as the lignocellulose degrading Penicillium oxalicum JUA10-1(formerly named as Penicillium decumbens). To resolve this problem, we constructed a genetic manipulation system taking advantage of two established genetic systems: the Cre-loxP system and Tet-on system in P. oxalicum JUA10-1. This system is efficient and convenient. The expression of Cre recombinase was activated by doxycycline since it was controlled by Tet-on system. Using this system, two genes, ligD and bglI, were sequentially disrupted by loxP flanked ptrA. The successful application of this procedure will provide a useful tool for genetic engineering in filamentous fungi. This system will also play an important role in improving the productivity of interesting products and minimizing by-product when fermented by filamentous fungi. PMID:27148179

The role of genetically engineered pigs in xenotransplantation research.

PubMed

Cooper, David K C; Ekser, Burcin; Ramsoondar, Jagdeece; Phelps, Carol; Ayares, David

2016-01-01

There is a critical shortage in the number of deceased human organs that become available for the purposes of clinical transplantation. This problem might be resolved by the transplantation of organs from pigs genetically engineered to protect them from the human immune response. The pathobiological barriers to successful pig organ transplantation in primates include activation of the innate and adaptive immune systems, coagulation dysregulation and inflammation. Genetic engineering of the pig as an organ source has increased the survival of the transplanted pig heart, kidney, islet and corneal graft in non-human primates (NHPs) from minutes to months or occasionally years. Genetic engineering may also contribute to any physiological barriers that might be identified, as well as to reducing the risks of transfer of a potentially infectious micro-organism with the organ. There are now an estimated 40 or more genetic alterations that have been carried out in pigs, with some pigs expressing five or six manipulations. With the new technology now available, it will become increasingly common for a pig to express even more genetic manipulations, and these could be tested in the pig-to-NHP models to assess their efficacy and benefit. It is therefore likely that clinical trials of pig kidney, heart and islet transplantation will become feasible in the near future. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Genetic engineering of cyanobacteria as biodiesel feedstock.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruffing, Anne.; Trahan, Christine Alexandra; Jones, Howland D. T.

2013-01-01

Algal biofuels are a renewable energy source with the potential to replace conventional petroleum-based fuels, while simultaneously reducing greenhouse gas emissions. The economic feasibility of commercial algal fuel production, however, is limited by low productivity of the natural algal strains. The project described in this SAND report addresses this low algal productivity by genetically engineering cyanobacteria (i.e. blue-green algae) to produce free fatty acids as fuel precursors. The engineered strains were characterized using Sandias unique imaging capabilities along with cutting-edge RNA-seq technology. These tools are applied to identify additional genetic targets for improving fuel production in cyanobacteria. This proof-of-concept studymore » demonstrates successful fuel production from engineered cyanobacteria, identifies potential limitations, and investigates several strategies to overcome these limitations. This project was funded from FY10-FY13 through the President Harry S. Truman Fellowship in National Security Science and Engineering, a program sponsored by the LDRD office at Sandia National Laboratories.« less

Genome engineering and plant breeding: impact on trait discovery and development.

PubMed

Nogué, Fabien; Mara, Kostlend; Collonnier, Cécile; Casacuberta, Josep M

2016-07-01

New tools for the precise modification of crops genes are now available for the engineering of new ideotypes. A future challenge in this emerging field of genome engineering is to develop efficient methods for allele mining. Genome engineering tools are now available in plants, including major crops, to modify in a predictable manner a given gene. These new techniques have a tremendous potential for a spectacular acceleration of the plant breeding process. Here, we discuss how genetic diversity has always been the raw material for breeders and how they have always taken advantage of the best available science to use, and when possible, increase, this genetic diversity. We will present why the advent of these new techniques gives to the breeders extremely powerful tools for crop breeding, but also why this will require the breeders and researchers to characterize the genes underlying this genetic diversity more precisely. Tackling these challenges should permit the engineering of optimized alleles assortments in an unprecedented and controlled way.

Inter-DNA Attraction Mediated by Divalent Counterions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu Xiangyun; Andresen, Kurt; Kwok, Lisa W.

2007-07-20

Can nonspecifically bound divalent counterions induce attraction between DNA strands? Here, we present experimental evidence demonstrating attraction between short DNA strands mediated by Mg{sup 2+} ions. Solution small angle x-ray scattering data collected as a function of DNA concentration enable model independent extraction of the second virial coefficient. As the [Mg{sup 2+}] increases, this coefficient turns from positive to negative reflecting the transition from repulsive to attractive inter-DNA interaction. This surprising observation is corroborated by independent light scattering experiments. The dependence of the observed attraction on experimental parameters including DNA length provides valuable clues to its origin.

Development of a Genetically Engineered Venezuelan Equine Encephalitis Virus Vaccine

DTIC Science & Technology

1988-12-20

immunization, the horses will be returned to the large animal biocontainment facility to be challenged with equine virulent VEE virus. The animals will be...AD £IT FiLE C p DEVELOPMENT OF A GENETICALLY ENGINEERED VENEZUELAN EQUINE ENCEPHALITIS VIRUS VACCINE ANNUAL REPORT to DENNIS W. TRENT 0DECEMBER 20...Engineered Venezuelan Equine Encephalitis Virus Vaccine 12. PERSONAL AUTHOR(S) Dennis W. Trent 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT

Sequestration of carbon dioxide with hydrogen to useful products

DOEpatents

Adams, Michael W. W.; Kelly, Robert M.; Hawkins, Aaron B.; Menon, Angeli Lal; Lipscomb, Gina Lynette Pries; Schut, Gerrit Jan

2017-03-07

Provided herein are genetically engineered microbes that include at least a portion of a carbon fixation pathway, and in one embodiment, use molecular hydrogen to drive carbon dioxide fixation. In one embodiment, the genetically engineered microbe is modified to convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof at levels greater than a control microbe. Other products may also be produced. Also provided herein are cell free compositions that convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof. Also provided herein are methods of using the genetically engineered microbes and the cell free compositions.

PERSISTENCE OF A SURROGATE FOR A GENETICALLY ENGINEERED CELLULOLYTIC MICROORGANISM AND EFFECTS ON AQUATIC COMMUNITY AND ECOSYSTEM PROPERTIES: MICROCOSM AND STREAM COMPARISONS

EPA Science Inventory

Our research objectives were to: (1) determine the persistence of an introduced surrogate (Cellulomonas sp NRC 2406) for a genetically engineered microorganism (GEM) in three streamlined habitats; sediments, growths of Cladophora (Chlorophyta), and leaf packs, (2) test ommunity a...

77 FR 41363 - BASF Plant Science, LP; Availability of Petition for Determination of Nonregulated Status of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... Genetically Engineered for Herbicide Tolerance AGENCY: Animal and Plant Health Inspection Service, USDA... herbicides in the imidazolinone family. The petition has been submitted in accordance with our regulations... event BPS-CV127-9, which has been genetically engineered for tolerance to herbicides in the...

77 FR 41367 - Dow AgroSciences LLC; Availability of Petition, Plant Pest Risk Assessment, and Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... Assessment for Determination of Nonregulated Status of Soybean Genetically Engineered for Herbicide Tolerance... been genetically engineered for tolerance to broadleaf herbicides in the phenoxy auxin group (such as the herbicide 2,4-D) and the herbicide glufosinate. The petition has been submitted in accordance with...

77 FR 41361 - Dow AgroSciences LLC; Availability of Petition for Determination of Nonregulated Status of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... Genetically Engineered for Herbicide Tolerance AGENCY: Animal and Plant Health Inspection Service, USDA... broadleaf herbicides in the phenoxy auxin group (such as the herbicide 2,4-D) and the herbicides glyphosate...-44406-6, which has been genetically engineered for tolerance to broadleaf herbicides in the phenoxy...

Genetic Engineering of Animals for Medical Research: Students' Views.

ERIC Educational Resources Information Center

Hill, Ruaraidh; Stanisstreet, Martin; O'Sullivan, Helen; Boyes, Edward

1999-01-01

Reports on the results of a survey meant to ascertain the views of 16- to 18-year-old students (n=778) on using animals in medical research. Suggests that students have no greater objection to the use of genetically engineered animals over naturally bred animals in medical research. Contains 16 references. (Author/WRM)

Projecting potential adoption of genetically engineered freeze-tolerant Eucalyptus in the United States

Treesearch

David N. Wear; Ernest Dixon IV; Robert C. Abt; Navinder Singh

2015-01-01

Development of commercial Eucalyptus plantations has been limited in the United States because of the species’ sensitivity to freezing temperatures. Recently developed genetically engineered clones of a Eucalyptus hybrid, which confer freeze tolerance, could expand the range of commercial plantations. This study explores how...

[The application of genetic engineering to the petroleum biodesulfurization].

PubMed

Tong, M Y; Fang, X C; Ma, T; Zhang, Q

2001-11-01

The developed course and reaction mechanisms of petroleum biodesulfurization were introduced. The recent development of genetic engineering technology, which used in desulfuration strain's construction, reconstruction and other fields, was summarized emphatically. Its current research situation internal and overseas and the developing prospect were simply analyzed, and our research designs were submitted.

'HoneySweet' plum - a valuable genetically engineered fruit-tree cultivar and germplasm resource

USDA-ARS?s Scientific Manuscript database

‘HoneySweet’ is a plum variety developed through genetic engineering to be highly resistant to plum pox potyvirus (PPV), the causal agent of sharka disease, that threatens stone-fruit industries world-wide and most specifically, in Europe. Field testing for over 15 years in Europe has demonstrated ...

Programmable cells: Interfacing natural and engineered gene networks

NASA Astrophysics Data System (ADS)

Kobayashi, Hideki; Kærn, Mads; Araki, Michihiro; Chung, Kristy; Gardner, Timothy S.; Cantor, Charles R.; Collins, James J.

2004-06-01

Novel cellular behaviors and characteristics can be obtained by coupling engineered gene networks to the cell's natural regulatory circuitry through appropriately designed input and output interfaces. Here, we demonstrate how an engineered genetic circuit can be used to construct cells that respond to biological signals in a predetermined and programmable fashion. We employ a modular design strategy to create Escherichia coli strains where a genetic toggle switch is interfaced with: (i) the SOS signaling pathway responding to DNA damage, and (ii) a transgenic quorum sensing signaling pathway from Vibrio fischeri. The genetic toggle switch endows these strains with binary response dynamics and an epigenetic inheritance that supports a persistent phenotypic alteration in response to transient signals. These features are exploited to engineer cells that form biofilms in response to DNA-damaging agents and cells that activate protein synthesis when the cell population reaches a critical density. Our work represents a step toward the development of "plug-and-play" genetic circuitry that can be used to create cells with programmable behaviors. heterologous gene expression | synthetic biology | Escherichia coli

Genomic landscapes of endogenous retroviruses unveil intricate genetics of conventional and genetically-engineered laboratory mouse strains.

PubMed

Lee, Kang-Hoon; Lim, Debora; Chiu, Sophia; Greenhalgh, David; Cho, Kiho

2016-04-01

Laboratory strains of mice, both conventional and genetically engineered, have been introduced as critical components of a broad range of studies investigating normal and disease biology. Currently, the genetic identity of laboratory mice is primarily confirmed by surveying polymorphisms in selected sets of "conventional" genes and/or microsatellites in the absence of a single completely sequenced mouse genome. First, we examined variations in the genomic landscapes of transposable repetitive elements, named the TREome, in conventional and genetically engineered mouse strains using murine leukemia virus-type endogenous retroviruses (MLV-ERVs) as a probe. A survey of the genomes from 56 conventional strains revealed strain-specific TREome landscapes, and certain families (e.g., C57BL) of strains were discernible with defined patterns. Interestingly, the TREome landscapes of C3H/HeJ (toll-like receptor-4 [TLR4] mutant) inbred mice were different from its control C3H/HeOuJ (TLR4 wild-type) strain. In addition, a CD14 knock-out strain had a distinct TREome landscape compared to its control/backcross C57BL/6J strain. Second, an examination of superantigen (SAg, a "TREome gene") coding sequences of mouse mammary tumor virus-type ERVs in the genomes of the 46 conventional strains revealed a high diversity, suggesting a potential role of SAgs in strain-specific immune phenotypes. The findings from this study indicate that unexplored and intricate genomic variations exist in laboratory mouse strains, both conventional and genetically engineered. The TREome-based high-resolution genetics surveillance system for laboratory mice would contribute to efficient study design with quality control and accurate data interpretation. This genetics system can be easily adapted to other species ranging from plants to humans. Copyright © 2016 Elsevier Inc. All rights reserved.

Improving the selection efficiency of the counter-selection marker pheS* for the genetic engineering of Bacillus amyloliquefaciens.

PubMed

Kharchenko, Maria S; Teslya, Petr N; Babaeva, Maria N; Zakataeva, Natalia P

2018-05-01

Bacillus subtilis pheS was genetically modified to obtain a counter-selection marker with high selection efficiency in Bacillus amyloliquefaciens. The application of the new replication-thermosensitive integrative vector pNZTM1, containing this marker, pheS BsT255S/A309G , with a two-step replacement recombination procedure provides an effective tool for the genetic engineering of industrially important Bacillus species. Copyright © 2018. Published by Elsevier B.V.

Current biotechnological developments in Belgium.

PubMed

Masschelein, C A; Callegari, J P; Laurent, M; Simon, J P; Taeymans, D

1989-01-01

In recent years, actions have been undertaken by the Belgian government to promote process innovation and technical diversification. Research programs are initiated and coordinated by the study committee for biotechnology setup within the Institute for Scientific Research in Industry and Agriculture (IRSIA). As a result of this action, the main areas where biotechnological processes are developed or commercially exploited include plant genetics, protein engineering, hybridoma technology, biopesticides, production by genetic engineering of vaccines and drugs, monoclonal detection of human and animal deseases, process reactors for aerobic and anaerobic wastewater treatment, and genetic modification of yeast and bacteria as a base for biomass and energy. Development research also includes new fermentation technologies principally based on immobilization of microorganisms, reactor design, and optimization of unit operations involved in downstream processing. Food, pharmaceutical, and chemical industries are involved in genetic engineering and biotechnology and each of these sectors is overviewed in this paper.

Genetic engineering of mesenchymal stem cells and its application in human disease therapy.

PubMed

Hodgkinson, Conrad P; Gomez, José A; Mirotsou, Maria; Dzau, Victor J

2010-11-01

The use of stem cells for tissue regeneration and repair is advancing both at the bench and bedside. Stem cells isolated from bone marrow are currently being tested for their therapeutic potential in a variety of clinical conditions including cardiovascular injury, kidney failure, cancer, and neurological and bone disorders. Despite the advantages, stem cell therapy is still limited by low survival, engraftment, and homing to damage area as well as inefficiencies in differentiating into fully functional tissues. Genetic engineering of mesenchymal stem cells is being explored as a means to circumvent some of these problems. This review presents the current understanding of the use of genetically engineered mesenchymal stem cells in human disease therapy with emphasis on genetic modifications aimed to improve survival, homing, angiogenesis, and heart function after myocardial infarction. Advancements in other disease areas are also discussed.

Production of human lactoferrin and lysozyme in the milk of transgenic dairy animals: past, present, and future.

PubMed

Cooper, Caitlin A; Maga, Elizabeth A; Murray, James D

2015-08-01

Genetic engineering, which was first developed in the 1980s, allows for specific additions to animals' genomes that are not possible through conventional breeding. Using genetic engineering to improve agricultural animals was first suggested when the technology was in the early stages of development by Palmiter et al. (Nature 300:611-615, 1982). One of the first agricultural applications identified was generating transgenic dairy animals that could produce altered or novel proteins in their milk. Human milk contains high levels of antimicrobial proteins that are found in low concentrations in the milk of ruminants, including the antimicrobial proteins lactoferrin and lysozyme. Lactoferrin and lysozyme are both part of the innate immune system and are secreted in tears, mucus, and throughout the gastrointestinal (GI) tract. Due to their antimicrobial properties and abundance in human milk, multiple lines of transgenic dairy animals that produce either human lactoferrin or human lysozyme have been developed. The focus of this review is to catalogue the different lines of genetically engineered dairy animals that produce either recombinant lactoferrin or lysozyme that have been generated over the years as well as compare the wealth of research that has been done on the in vitro and in vivo effects of the milk they produce. While recent advances including the development of CRISPRs and TALENs have removed many of the technical barriers to predictable and efficient genetic engineering in agricultural species, there are still many political and regulatory hurdles before genetic engineering can be used in agriculture. It is important to consider the substantial amount of work that has been done thus far on well established lines of genetically engineered animals evaluating both the animals themselves and the products they yield to identify the most effective path forward for future research and acceptance of this technology.

Foundations and Emerging Paradigms for Computing in Living Cells.

PubMed

Ma, Kevin C; Perli, Samuel D; Lu, Timothy K

2016-02-27

Genetic circuits, composed of complex networks of interacting molecular machines, enable living systems to sense their dynamic environments, perform computation on the inputs, and formulate appropriate outputs. By rewiring and expanding these circuits with novel parts and modules, synthetic biologists have adapted living systems into vibrant substrates for engineering. Diverse paradigms have emerged for designing, modeling, constructing, and characterizing such artificial genetic systems. In this paper, we first provide an overview of recent advances in the development of genetic parts and highlight key engineering approaches. We then review the assembly of these parts into synthetic circuits from the perspectives of digital and analog logic, systems biology, and metabolic engineering, three areas of particular theoretical and practical interest. Finally, we discuss notable challenges that the field of synthetic biology still faces in achieving reliable and predictable forward-engineering of artificial biological circuits. Copyright © 2016. Published by Elsevier Ltd.

Two Divalent Metal Ions and Conformational Changes Play Roles in the Hammerhead Ribozyme Cleavage Reaction

PubMed Central

Mir, Aamir; Chen, Ji; Robinson, Kyle; Lendy, Emma; Goodman, Jaclyn; Neau, David; Golden, Barbara L.

2016-01-01

The hammerhead ribozyme is a self-cleaving RNA broadly dispersed across all kingdoms of life. Although it was the first of the small, nucleolytic ribozymes discovered, the mechanism by which it catalyzes its reaction remains elusive. The nucleobase of G12 is well positioned to be a general base, but it is unclear if or how this guanine base becomes activated for proton transfer. Metal ions have been implicated in the chemical mechanism, but no interactions between divalent metal ions and the cleavage site have been observed crystallographically. To better understand how this ribozyme functions, we have solved crystal structures of wild-type and G12A mutant ribozymes. We observe a pH-dependent conformational change centered around G12, consistent with this nucleotide becoming deprotonated. Crystallographic and kinetic analysis of the G12A mutant reveals a Zn2+ specificity switch suggesting a direct interaction between a divalent metal ion and the purine at position 12. The metal ion specificity switch and the pH–rate profile of the G12A mutant suggest that the minor imino tautomer of A12 serves as the general base in the mutant ribozyme. We propose a model in which the hammerhead ribozyme rearranges prior to the cleavage reaction, positioning two divalent metal ions in the process. The first metal ion, positioned near G12, becomes directly coordinated to the O6 keto oxygen, to lower the pKa of the general base and organize the active site. The second metal ion, positioned near G10.1, bridges the N7 of G10.1 and the scissile phosphate and may participate directly in the cleavage reaction. PMID:26398724

Effect of diuretics on renal tubular transport of calcium and magnesium.

PubMed

Alexander, R Todd; Dimke, Henrik

2017-06-01

Calcium (Ca 2+ ) and Magnesium (Mg 2+ ) reabsorption along the renal tubule is dependent on distinct trans- and paracellular pathways. Our understanding of the molecular machinery involved is increasing. Ca 2+ and Mg 2+ reclamation in kidney is dependent on a diverse array of proteins, which are important for both forming divalent cation-permeable pores and channels, but also for generating the necessary driving forces for Ca 2+ and Mg 2+ transport. Alterations in these molecular constituents can have profound effects on tubular Ca 2+ and Mg 2+ handling. Diuretics are used to treat a large range of clinical conditions, but most commonly for the management of blood pressure and fluid balance. The pharmacological targets of diuretics generally directly facilitate sodium (Na + ) transport, but also indirectly affect renal Ca 2+ and Mg 2+ handling, i.e., by establishing a prerequisite electrochemical gradient. It is therefore not surprising that substantial alterations in divalent cation handling can be observed following diuretic treatment. The effects of diuretics on renal Ca 2+ and Mg 2+ handling are reviewed in the context of the present understanding of basal molecular mechanisms of Ca 2+ and Mg 2+ transport. Acetazolamide, osmotic diuretics, Na + /H + exchanger (NHE3) inhibitors, and antidiabetic Na + /glucose cotransporter type 2 (SGLT) blocking compounds, target the proximal tubule, where paracellular Ca 2+ transport predominates. Loop diuretics and renal outer medullary K + (ROMK) inhibitors block thick ascending limb transport, a segment with significant paracellular Ca 2+ and Mg 2+ transport. Thiazides target the distal convoluted tubule; however, their effect on divalent cation transport is not limited to that segment. Finally, potassium-sparing diuretics, which inhibit electrogenic Na + transport at distal sites, can also affect divalent cation transport. Copyright © 2017 the American Physiological Society.

Distinct reaction pathway promoted by non-divalent-metal cations in a tertiary stabilized hammerhead ribozyme

PubMed Central

Roychowdhury-Saha, Manami; Burke, Donald H.

2007-01-01

Divalent ion sensitivity of hammerhead ribozymes is significantly reduced when the RNA structure includes appropriate tertiary stabilization. Therefore, we investigated the activity of the tertiary stabilized “RzB” hammerhead ribozyme in several nondivalent ions. Ribozyme RzB is active in spermidine and Na+ alone, although the cleavage rates are reduced by more than 1,000-fold relative to the rates observed in Mg2+ and in transition metal ions. The trivalent cobalt hexammine (CoHex) ion is often used as an exchange-inert analog of hydrated magnesium ion. Trans-cleavage rates exceeded 8 min−1 in 20 mM CoHex, which promoted cleavage through outersphere interactions. The stimulation of catalysis afforded by the tertiary structural interactions within RzB does not require Mg2+, unlike other extended hammerhead ribozymes. Site-specific interaction with at least one Mg2+ ion is suggested by CoHex competition experiments. In the presence of a constant, low concentration of Mg2+, low concentrations of CoHex decreased the rate by two to three orders of magnitude relative to the rate in Mg2+ alone. Cleavage rates increased as CoHex concentrations were raised further, but the final fraction cleaved was lower than what was observed in CoHex or Mg2+ alone. These observations suggest that Mg2+ and CoHex compete for binding and that they cause misfolded structures when they are together. The results of this study support the existence of an alternate catalytic mechanism used by nondivalent ions (especially CoHex) that is distinct from the one promoted by divalent metal ions, and they imply that divalent metals influence catalysis through a specific nonstructural role. PMID:17456566

The Compact and Biologically Relevant Structure of Inter-α-inhibitor Is Maintained by the Chondroitin Sulfate Chain and Divalent Cations.

PubMed

Scavenius, Carsten; Nikolajsen, Camilla Lund; Stenvang, Marcel; Thøgersen, Ida B; Wyrożemski, Łukasz; Wisniewski, Hans-Georg; Otzen, Daniel E; Sanggaard, Kristian W; Enghild, Jan J

2016-02-26

Inter-α-inhibitor is a proteoglycan of unique structure. The protein consists of three subunits, heavy chain 1, heavy chain 2, and bikunin covalently joined by a chondroitin sulfate chain originating at Ser-10 of bikunin. Inter-α-inhibitor interacts with an inflammation-associated protein, tumor necrosis factor-inducible gene 6 protein, in the extracellular matrix. This interaction leads to transfer of the heavy chains from the chondroitin sulfate of inter-α-inhibitor to hyaluronan and consequently to matrix stabilization. Divalent cations and heavy chain 2 are essential co-factors in this transfer reaction. In the present study, we have investigated how divalent cations in concert with the chondroitin sulfate chain influence the structure and stability of inter-α-inhibitor. The results showed that Mg(2+) or Mn(2+), but not Ca(2+), induced a conformational change in inter-α-inhibitor as evidenced by a decrease in the Stokes radius and a bikunin chondroitin sulfate-dependent increase of the thermodynamic stability. This structure was shown to be essential for the ability of inter-α-inhibitor to participate in extracellular matrix stabilization. In addition, the data revealed that bikunin was positioned adjacent to both heavy chains and that the two heavy chains also were in close proximity. The chondroitin sulfate chain interacted with all protein components and inter-α-inhibitor dissociated when it was degraded. Conventional purification protocols result in the removal of the Mg(2+) found in plasma and because divalent cations influence the conformation and affect function it is important to consider this when characterizing the biological activity of inter-α-inhibitor. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Binding of Divalent Cations to Polygalacturonate: A Mechanism Driven by the Hydration Water.

PubMed

Huynh, Uyen T D; Lerbret, Adrien; Neiers, Fabrice; Chambin, Odile; Assifaoui, Ali

2016-02-11

We have investigated the interactions between polygalacturonate (polyGal) and four divalent cations (M(2+) = Ba(2+), Ca(2+), Mg(2+), Zn(2+)) that differ in size and affinity for water. Our results evidence that M(2+)-polyGal interactions are intimately linked to the affinity of M(2+) for water. Mg(2+) interacts so strongly with water that it remains weakly bound to polyGal (polycondensation) by sharing water molecules from its first coordination shell with the carboxylate groups of polyGal. In contrast, the other cations form transient ionic pairs with polyGal by releasing preferentially one water molecule (for Zn(2+)) or two (for Ca(2+) and Ba(2+)), which corresponds to monodentate and bidentate binding modes with carboxylates, respectively. The mechanism for the binding of these three divalent cations to polyGal can be described by two steps: (i) monocomplexation and formation of point-like cross-links between polyGal chains (at low M(2+)/Gal molar ratios, R) and (ii) dimerization (at higher R). The threshold molar ratio, R*, between these two steps depends on the nature of divalent cations and is lower for calcium ions (R* < 0.1) than for zinc and barium ions (R* > 0.3). This difference may be explained by the intermediate affinity of Ca(2+) for water with respect to those of Zn(2+) and Ba(2+), which may induce the formation of cross-links of intermediate flexibility. By comparison, the lower and higher flexibilities of the cross-links formed by Zn(2+) and Ba(2+), respectively, may shift the formation of dimers to higher molar ratios (R*).

Two Divalent Metal Ions and Conformational Changes Play Roles in the Hammerhead Ribozyme Cleavage Reaction.

PubMed

Mir, Aamir; Chen, Ji; Robinson, Kyle; Lendy, Emma; Goodman, Jaclyn; Neau, David; Golden, Barbara L

2015-10-20

The hammerhead ribozyme is a self-cleaving RNA broadly dispersed across all kingdoms of life. Although it was the first of the small, nucleolytic ribozymes discovered, the mechanism by which it catalyzes its reaction remains elusive. The nucleobase of G12 is well positioned to be a general base, but it is unclear if or how this guanine base becomes activated for proton transfer. Metal ions have been implicated in the chemical mechanism, but no interactions between divalent metal ions and the cleavage site have been observed crystallographically. To better understand how this ribozyme functions, we have solved crystal structures of wild-type and G12A mutant ribozymes. We observe a pH-dependent conformational change centered around G12, consistent with this nucleotide becoming deprotonated. Crystallographic and kinetic analysis of the G12A mutant reveals a Zn(2+) specificity switch suggesting a direct interaction between a divalent metal ion and the purine at position 12. The metal ion specificity switch and the pH-rate profile of the G12A mutant suggest that the minor imino tautomer of A12 serves as the general base in the mutant ribozyme. We propose a model in which the hammerhead ribozyme rearranges prior to the cleavage reaction, positioning two divalent metal ions in the process. The first metal ion, positioned near G12, becomes directly coordinated to the O6 keto oxygen, to lower the pKa of the general base and organize the active site. The second metal ion, positioned near G10.1, bridges the N7 of G10.1 and the scissile phosphate and may participate directly in the cleavage reaction.

Comparison of the effects of divalent cations on the noradrenaline-evoked cation current in rabbit portal vein smooth muscle cells

PubMed Central

Aromolaran, A S; Large, W A

1999-01-01

The facilitatory effects of external Ca2+, Sr2+ and Ba2+ (Cao2+, Sro2+ and Bao2+) on the noradrenaline-evoked non-selective cation current (Icat) were compared in rabbit portal vein smooth muscle cells using patch pipette techniques. All divalent cations tested potentiated the amplitude of Icat and the potency sequence was Cao2+ > Sro2+ > Bao2+. Cao2+ and Sro2+ increased the amplitude of Icat by about eight times whereas Bao2+ produced only a threefold facilitation. The current-voltage relationship of Icat was not changed by Cao2+, Sro2+ or Bao2+. From noise analysis the single channel conductance (γ) was approximately 10 pS in divalent cation-free solution but was about 20 pS with Cao2+, Sro2+ and Bao2+. From noise and voltage-jump experiments it was apparent that at least three kinetically resolvable channel states are associated with Icat in divalent cation-free solution. Cao2+ and Sro2+ produced marked changes in the characteristics of the power spectrum and relaxations of Icat in response to voltage steps, consistent with a shift in the equilibrium between the channel states, whereas Bao2+ produced minimal effects. The data show that Cao2+, Sro2+ and Bao2+ increase the amplitude of Icat, which results in part from an increase in the single channel conductance. In addition the results suggest that Cao2+ and Sro2+ alter the kinetic behaviour of the single channels whereas Bao2+ has little effect on the equilibrium between the channel states. PMID:10545143

Directed evolution and synthetic biology applications to microbial systems.

PubMed

Bassalo, Marcelo C; Liu, Rongming; Gill, Ryan T

2016-06-01

Biotechnology applications require engineering complex multi-genic traits. The lack of knowledge on the genetic basis of complex phenotypes restricts our ability to rationally engineer them. However, complex phenotypes can be engineered at the systems level, utilizing directed evolution strategies that drive whole biological systems toward desired phenotypes without requiring prior knowledge of the genetic basis of the targeted trait. Recent developments in the synthetic biology field accelerates the directed evolution cycle, facilitating engineering of increasingly complex traits in biological systems. In this review, we summarize some of the most recent advances in directed evolution and synthetic biology that allows engineering of complex traits in microbial systems. Then, we discuss applications that can be achieved through engineering at the systems level. Copyright © 2016 Elsevier Ltd. All rights reserved.

Engineering Delivery Vehicles for Genome Editing.

PubMed

Nelson, Christopher E; Gersbach, Charles A

2016-06-07

The field of genome engineering has created new possibilities for gene therapy, including improved animal models of disease, engineered cell therapies, and in vivo gene repair. The most significant challenge for the clinical translation of genome engineering is the development of safe and effective delivery vehicles. A large body of work has applied genome engineering to genetic modification in vitro, and clinical trials have begun using cells modified by genome editing. Now, promising preclinical work is beginning to apply these tools in vivo. This article summarizes the development of genome engineering platforms, including meganucleases, zinc finger nucleases, TALENs, and CRISPR/Cas9, and their flexibility for precise genetic modifications. The prospects for the development of safe and effective viral and nonviral delivery vehicles for genome editing are reviewed, and promising advances in particular therapeutic applications are discussed.

Biotechnological advancement in genetic improvement of broccoli (Brassica oleracea L. var. italica), an important vegetable crop.

PubMed

Kumar, Pankaj; Srivastava, Dinesh Kumar

2016-07-01

With the advent of molecular biotechnology, plant genetic engineering techniques have opened an avenue for the genetic improvement of important vegetable crops. Vegetable crop productivity and quality are seriously affected by various biotic and abiotic stresses which destabilize rural economies in many countries. Moreover, absence of proper post-harvest storage and processing facilities leads to qualitative and quantitative losses. In the past four decades, conventional breeding has significantly contributed to the improvement of vegetable yields, quality, post-harvest life, and resistance to biotic and abiotic stresses. However, there are many constraints in conventional breeding, which can only be overcome by advancements made in modern biology. Broccoli (Brassica oleracea L. var. italica) is an important vegetable crop, of the family Brassicaceae; however, various biotic and abiotic stresses cause enormous crop yield losses during the commercial cultivation of broccoli. Thus, genetic engineering can be used as a tool to add specific characteristics to existing cultivars. However, a pre-requisite for transferring genes into plants is the availability of efficient regeneration and transformation techniques. Recent advances in plant genetic engineering provide an opportunity to improve broccoli in many aspects. The goal of this review is to summarize genetic transformation studies on broccoli to draw the attention of researchers and scientists for its further genetic advancement.

Genetic engineering of a mouse: Dr. Frank Ruddle and somatic cell genetics.

PubMed

Jones, Dennis

2011-06-01

Genetic engineering is the process of modifying an organism's genetic composition by adding foreign genes to produce desired traits or evaluate function. Dr. Jon W. Gordon and Sterling Professor Emeritus at Yale Dr. Frank H. Ruddle were pioneers in mammalian gene transfer research. Their research resulted in production of the first transgenic animals, which contained foreign DNA that was passed on to offspring. Transgenic mice have revolutionized biology, medicine, and biotechnology in the 21st century. In brief, this review revisits their creation of transgenic mice and discusses a few evolving applications of their transgenic technology used in biomedical research.

Dynamic role and importance of surrogate species for assessing potential adverse environmental impacts of genetically engineered insect-resistant plants on non-target organisms

USDA-ARS?s Scientific Manuscript database

Surrogate species have a long history of use in research and regulatory settings to understand the potentially harmful effects of toxic substances including pesticides. More recently, surrogate species have been used to evaluate the potential effects of proteins contained in genetically engineered ...

Can Man Control His Biological Evolution? A Symposium on Genetic Engineering. Probabilities and Practicalities

ERIC Educational Resources Information Center

Djerassi, Carl

1972-01-01

Manipulation of genes in human beings on a large scale is not possible under present conditions because it lacks economic potential and other attractions for industry. However, preventive'' genetic engineering may be a field for vast research in the future and will perhaps be approved by governments, parishes, people and industry. (PS)

Enhancing the Internationalisation of Distance Education in the Biological Sciences: The DUNE Project and Genetic Engineering.

ERIC Educational Resources Information Center

Leach, C. K.; And Others

1997-01-01

Describes the Distance Educational Network of Europe (DUNE) project that aims at enhancing the development of distance education in an international context. Highlights issues relating to the delivery of distance-learning courses in a transnational forum. Describes the genetic engineering course that aims at explaining the core techniques of…

77 FR 41357 - Monsanto Co.; Availability of Petition for Determination of Nonregulated Status of Canola...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... Produced Through Genetic Engineering Which Are Plant Pests or Which There Is Reason to Believe Are Plant... into the environment) of organisms and products altered or produced through genetic engineering that... CP4 EPSPS expression in male reproductive tissues (i.e., pollen). Enhanced CP4 EPSPS expression in the...

Finding Patterns of Emergence in Science and Technology

DTIC Science & Technology

2012-09-24

formal evaluation scheduled – Case Studies, Eight Examples: Tissue Engineering, Cold Fusion, RF Metamaterials, DNA Microarrays, Genetic Algorithms, RNAi...emerging capabilities Case Studies, Eight Examples: • Tissue Engineering, Cold Fusion, RF Metamaterials, DNA Microarrays, Genetic Algorithms...Evidence Quality (i.e., the rubric ) and deliver comprehensible evidential support for nomination • Demonstrate proof-of-concept nomination for Chinese

77 FR 42693 - Monsanto Company and KWS SAAT AG; Determination of Nonregulated Status of Sugar Beet Genetically...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-20

... for Tolerance to the Herbicide Glyphosate AGENCY: Animal and Plant Health Inspection Service, USDA... engineered for tolerance to the herbicide glyphosate, designated as H7-1, is no longer considered a regulated... as event H7-1, which has been genetically engineered for tolerance to the herbicide glyphosate. The...

76 FR 80871 - Monsanto Co.; Availability of Petition, Plant Pest Risk Assessment, and Environmental Assessment...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-27

... genetically engineered to produce stearidonic acid, an omega-3 fatty acid not found in conventional soybean... genetically engineered to produce stearidonic acid, an omega-3 fatty acid not found in conventional soybean... parts 1500-1508), (3) USDA regulations implementing NEPA (7 CFR part 1b), and (4) APHIS' NEPA...

Genetic engineering of syringyl-enriched lignin in plants

DOEpatents

Chiang, Vincent Lee; Li, Laigeng

2004-11-02

The present invention relates to a novel DNA sequence, which encodes a previously unidentified lignin biosynthetic pathway enzyme, sinapyl alcohol dehydrogenase (SAD) that regulates the biosynthesis of syringyl lignin in plants. Also provided are methods for incorporating this novel SAD gene sequence or substantially similar sequences into a plant genome for genetic engineering of syringyl-enriched lignin in plants.

Procedures and best management practices for genetically engineered traits in USDA/ARS germplasm and breeding lines

USDA-ARS?s Scientific Manuscript database

Two decades have passed since the commercialization in the U. S. of crops with genetically engineered (GE) traits. Today more than 80% of corn, soybean, canola, sugar beet and cotton acreage in the United States is planted to transgenic cultivars, but concerns exist regarding how best to manage the ...

'HoneySweet' (C5), the first genetically engineered Plum pox virus-resistant plum (Prunus domestica L.) cultivar

USDA-ARS?s Scientific Manuscript database

‘HoneySweet’ plum was released by the U.S. Department of Agriculture, Agricultural Research Service, to provide U.S. growers and P. domestica plum breeders with a high fruit quality plum cultivar resistant to Plum pox virus (PPV). ‘HoneySweet’ was developed through genetic engineering utilizing the...

Treating Cancer with Genetically Engineered T Cells

PubMed Central

Park, Tristen S.; Rosenberg, Steven A.; Morgan, Richard A.

2011-01-01

Administration of ex-vivo cultured, naturally occurring tumor-infiltrating lymphocytes (TILs) have been shown to mediate durable regression of melanoma tumors. However, the generation of TIL is not possible in all patients and there has been limited success in generating TIL in other cancers. Advances in genetic engineering have overcome these limitations by introducing tumor-antigen-targeting receptors into human T lymphocytes. Physicians can now genetically engineer lymphocytes to express highly active T-cell receptors (TCRs) or chimeric antigen receptors (CARs) targeting a variety of tumor antigens expressed in cancer patients. In this review we discuss the development of TCR and CAR gene transfer technology and the expansion of these therapies into different cancers with the recent demonstration of the clinical efficacy of these treatments. PMID:21663987

Genetic engineering of somatic cells to study and improve cardiac function.

PubMed

Kirkton, Robert D; Bursac, Nenad

2012-11-01

To demonstrate the utility of genetically engineered excitable cells for studies of basic electrophysiology and cardiac cell therapy. 'Zig-zag' networks of neonatal rat ventricular myocytes (NRVMs) were micropatterned onto thin elastomeric films to mimic the slow action potential (AP) conduction found in fibrotic myocardium. Addition of genetically engineered excitable human embryonic kidney cells (HEK-293 cells) ('Ex-293' cells stably expressing Kir2.1, Na(v)1.5, and Cx43 channels) increased both cardiac conduction velocity by 370% and twitch force amplitude by 64%. Furthermore, we stably expressed mutant Na(v)1.5 [A1924T (fast sodium channel mutant (substitution of alanine by threonine at amino acid 1924)] channels with hyperpolarized steady-state activation and showed that, despite a 71.6% reduction in peak I(Na), these cells propagated APs at the same velocity as the wild-type Na(v)1.5-expressing Ex-293 cells. Stable expression of Ca(v)3.3 (T-type voltage-gated calcium) channels in Ex-293 cells (to generate an 'ExCa-293' line) significantly increased their AP duration and reduced repolarization gradients in cocultures of these cells and NRVMs. Additional expression of an optogenetic construct [ChIEF (light-gated Channelrhodopsin mutant)]enabled light-based control of AP firing in ExCa-293 cells. We show that, despite being non-contractile, genetically engineered excitable cells can significantly improve both electrical and mechanical function of engineered cardiac tissues in vitro. We further demonstrate the utility of engineered cells for tissue-level studies of basic electrophysiology and cardiac channelopathies. In the future, this novel platform could be utilized in the high-throughput design of new genetically encoded indicators of cell electrical function, validation, and improvement of computer models of AP conduction, and development of novel engineered somatic cell therapies for the treatment of cardiac infarction and arrhythmias.

Genetic Engineering and the Amelioration of Genetic Defect

ERIC Educational Resources Information Center

Lederberg, Joshua

1970-01-01

Discusses the claims for a brave new world of genetic manipulation" and concludes that if we could agree upon applying genetic (or any other effective) remedies to global problems we probably would need no rescourse to them. Suggests that effective methods of preventing genetic disease are prevention of mutations and detection and…

Divalent Naphthalene Diimide Ligands Display High Selectivity for the Human Telomeric G‐quadruplex in K+ Buffer

PubMed Central

Street, Steven T. G.; Chin, Donovan N.; Hollingworth, Gregory J.; Berry, Monica

2017-01-01

Abstract Selective G‐quadruplex ligands offer great promise for the development of anti‐cancer therapies. A novel series of divalent cationic naphthalene diimide ligands that selectively bind to the hybrid form of the human telomeric G‐quadruplex in K+ buffer are described herein. We demonstrate that an imidazolium‐bearing mannoside‐conjugate is the most selective ligand to date for this quadruplex against several other quadruplex and duplex structures. We also show that a similarly selective methylpiperazine‐bearing ligand was more toxic to HeLa cancer cells than doxorubicin, whilst exhibiting three times less toxicity towards fetal lung fibroblasts WI‐38. PMID:28257554

Polymerization of a divalent/tetravalent metal-storing atom-mimicking dendrimer.

PubMed

Albrecht, Ken; Hirabayashi, Yuki; Otake, Masaya; Mendori, Shin; Tobari, Yuta; Azuma, Yasuo; Majima, Yutaka; Yamamoto, Kimihisa

2016-12-01

The phenylazomethine dendrimer (DPA) has a layer-by-layer electron density gradient that is an analog of the Bohr atom (atom mimicry). In combination with electron pair mimicry, the polymerization of this atom-mimicking dendrimer was achieved. The valency of the mimicked atom was controlled by changing the chemical structure of the dendrimer. By mimicking a divalent atom, a one-dimensional (1D) polymer was obtained, and by using a planar tetravalent atom mimic, a 2D polymer was obtained. These poly(dendrimer) polymers could store Lewis acids (SnCl 2 ) in their unoccupied orbitals, thus indicating that these poly(dendrimer) polymers consist of a series of nanocontainers.

Divalent metal ions modulated strong frustrated M(II)-Fe(III)3O (M = Fe, Mn, Mg) chains with metamagnetism only in a mixed valence iron complex.

PubMed

Wu, Qi-Long; Han, Song-De; Wang, Qing-Lun; Zhao, Jiong-Peng; Ma, Feng; Jiang, Xue; Liu, Fu-Chen; Bu, Xian-He

2015-10-25

Linking magnetically frustrated triangular FeO units by divalent metal ions (M(II) = Fe(II) for 1, Mn(II) for 2) gives isostructural 1D spin chains. Strong antiferromagnetic interactions were found in these complexes with significant frustrations but very interesting ferrimagnetic like transition and metamagnetism were found in mixed valence 1. By comparing the magnetic behaviours with isostructural complex 3 (with M(II) = Mg(II)), it is proposed that the spins of Fe(II) ions and Mn(II) ions have ferromagnetic and antiferromagnetic contributions respectively.

Atrial natriuretic peptide degradation by CPA47 cells: evidence for a divalent cation-independent cell-surface proteolytic activity.

PubMed

Frost, S J; Chen, Y M; Whitson, P A

1992-11-23

Atrial natriuretic peptide (ANP) is rapidly cleared and degraded in vivo. Nonguanylate-cyclase receptors (C-ANPR) and a metalloproteinase, neutral endopeptidase (EC 3.4.24.11) (NEP 24.11), are thought to be responsible for its metabolism. We investigated the mechanisms of ANP degradation by an endothelial-derived cell line, CPA47. CPA47 cells degraded 88% of 125I-ANP after 1 h at 37 degrees C as determined by HPLC. Medium preconditioned by these cells degraded 41% of the 125I-ANP, and this activity was inhibited by a divalent cation chelator, EDTA. Furthermore, a cell-surface proteolytic activity degraded 125I-ANP in the presence of EDTA when receptor-mediated endocytosis was inhibited either by low temperature (4 degrees C) or by hyperosmolarity at 37 degrees C. The metalloproteinase, NEP 24.11, is unlikely to be the cell-surface peptidase because 125I-ANP is degraded by CPA47 cells at 4 degrees C in the presence of 5 mM EDTA. These data indicate that CPA47 cells can degrade ANP by a novel divalent cation-independent cell-surface proteolytic activity.

Interactions of protamine with the marine bacterium, Pseudoalteromonas sp. NCIMB 2021.

PubMed

Pustam, A; Smith, C; Deering, C; Grosicki, K M T; Leng, T Y; Lin, S; Yang, J; Pink, D; Gill, T; Graham, L; Derksen, D; Bishop, C; Demont, M E; Wyeth, R C; Smith-Palmer, T

2014-03-01

Pseudoalteromonas sp. NCIMB 2021 (NCIMB 2021) was grown in synthetic seawater (SSW) containing pyruvate, in the presence (SSW(++) ) and absence (SSW(-) ) of divalent cations. Cultures contained single cells. Addition of the cationic antibacterial peptide (CAP), protamine, did not inhibit, but rather increased, the growth of NCIMB 2021 in SSW(++) and caused the bacteria to grow in chains. Bacterial growth was assessed using turbidity, cell counts and the sodium salt of resazurin. In SSW(-) , NCIMB 2021 was no longer resistant to protamine. The minimum inhibitory concentration (MIC) was 5 mg ml(-1) . Protamine is a cationic antimicrobial peptide (CAP), which is active against a variety of bacteria. This is the first in-depth study of the interaction of protamine with a marine bacterium, Pseudoalteromonas sp. NCIMB 2021. Our results show that protamine is only active in seawater in the absence of divalent cations. In the presence of the divalent cations, Mg(2+) and Ca(2+) , protamine enhances the growth of Pseudoalteromonas sp. NCIMB 2021 and produces chains rather than individual cells. These are important considerations when deciding on applications for protamine and in terms of understanding its mechanism of action. © 2013 The Society for Applied Microbiology.

Atrial natriuretic peptide degradation by CPA47 cells - Evidence for a divalent cation-independent cell-surface proteolytic activity

NASA Technical Reports Server (NTRS)

Frost, S. J.; Chen, Y. M.; Whitson, P. A.

1992-01-01

Atrial natriuretic peptide (ANP) is rapidly cleared and degraded in vivo. Nonguanylate-cyclase receptors (C-ANPR) and a metalloproteinase, neutral endopeptidase (EC 3.4.24.11) (NEP 24.11), are thought to be responsible for its metabolism. We investigated the mechanisms of ANP degradation by an endothelial-derived cell line, CPA47. CPA47 cells degraded 88 percent of 125I-ANP after 1 h at 37 degrees C as determined by HPLC. Medium preconditioned by these cells degraded 41 percent of the 125I-ANP, and this activity was inhibited by a divalent cation chelator, EDTA. Furthermore, a cell-surface proteolytic activity degraded 125I-ANP in the presence of EDTA when receptor-mediated endocytosis was inhibited either by low temperature (4 degrees C) or by hyperosmolarity at 37 degrees C. The metalloproteinase, NEP 24.11, is unlikely to be the cell-surface peptidase because 125I-ANP is degraded by CPA47 cells at 4 degrees C in the presence of 5 mM EDTA. These data indicate that CPA47 cells can degrade ANP by a novel divalent cation-independent cell-surface proteolytic activity.

Energy levels scheme simulation of divalent cobalt doped bismuth germanate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreici, Emiliana-Laura, E-mail: andreicilaura@yahoo.com; Petkova, Petya; Avram, Nicolae M.

The aim of this paper is to simulate the energy levels scheme for Bismuth Germanate (BGO) doped with divalent cobalt, in order to give a reliable explanation for spectral experimental data. In the semiempirical crystal field theory we first modeled the Crystal Field Parameters (CFPs) of BGO:Cr{sup 2+} system, in the frame of Exchange Charge Model (ECM), with actually site symmetry of the impurity ions after doping. The values of CFPs depend on the geometry of doped host matrix and by parameter G of ECM. First, we optimized the geometry of undoped BGO host matrix and afterwards, that of dopedmore » BGO with divalent cobalt. The charges effect of ligands and covalence bonding between cobalt cations and oxygen anions, in the cluster approach, also were taken into account. With the obtained values of the CFPs we simulate the energy levels scheme of cobalt ions, by diagonalizing the matrix of the doped crystal Hamiltonian. Obviously, energy levels and estimated Racah parameters B and C were compared with the experimental spectroscopic data and discussed. Comparison of obtained results with experimental data shows quite satisfactory, which justify the model and simulation schemes used for the title system.« less

Ion Exchange Polymeric Coatings for Selective Capacitive Deionization

NASA Astrophysics Data System (ADS)

Jain, Amit; Kim, Jun; Li, Qilin; Verduzco, Rafael

Capacitive deionization (CDI) is an energy-efficient technology for adsorbing and removing scalants and foulants from water by utilizing electric potential between porous carbon electrodes. Currently, industrial application of CDI is limited to low salinity waters due to the limited absorption capacities of carbon electrodes. However, CDI can potentially be used as a low-cost approach to selectively remove divalent ions from high salinity water. Divalent ions such as sulfonates and carbonates cause scaling and thus performance deterioration of membrane-based desalination systems. In this work, we investigated ion-exchange polymer coatings for use in a membrane capacitive deionization (MCDI) process for selective removal of divalent ions. Poly-Vinyl Alcohol (PVA) base polymer was crosslinked and charged using sulfo-succinic acid (SSA) to give a cation exchange layer. 50 um thick standalone polymer films had a permeability of 4.25*10-7 cm2/s for 10mM NaCl feed. Experiments on electrodes with as low as 10 υm thick coating of cation exchange polymer are under progress and will be evaluated on the basis of their selective salt removal efficiency and charge efficiency, and in future we will extend this work to sulfonated block copolymers and anion exchange polymers.

First use of a divalent lanthanide for visible-light-promoted photoredox catalysis† †Electronic supplementary information (ESI) available. CCDC 1539923. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc02479g

PubMed Central

Jenks, Tyler C.; Bailey, Matthew D.; Hovey, Jessica L.; Fernando, Shanilke; Basnayake, Gihan; Cross, Michael E.; Li, Wen

2017-01-01

We report the first catalytic use of a divalent lanthanide in visible-light-promoted bond-forming reactions. Our new precatalyst uses europium in the +2 oxidation state and is active in the presence of blue light from light-emitting diodes. The use of low-energy visible light reduces the occurrence of potential side reactions that might be induced by higher-energy UV light. The system described here uses zinc metal as a sacrificial reductant and is tolerant to wet, protic solvents. The catalyst can be made in situ from relatively inexpensive and air-stable EuCl3·6H2O, and the ligand can be synthesized in large quantities in two steps. With 0.5% loading of precatalyst, an average of 120 turnovers was observed in six hours for reductive coupling of benzyl chloride. We expect that the results will initiate the study of visible-light-promoted photoredox catalysis using divalent europium in a variety of reactions. PMID:29675173

Environmental risk assessment of a genetically-engineered microorganism: Erwinia carotovora

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orvos, D.R.

1989-01-01

Environmental use of genetically-engineered microorganisms (GEMs) has raised concerns over potential ecological impact. Development of microcosm systems useful in preliminary testing for risk assessment will provide useful information for predicting potential structural, functional, and genetic effects of GEM release. This study was executed to develop techniques that may be useful in risk assessment and microbial ecology, to ascertain which parameters are useful in determining risk and to predict risk from releasing an engineered strain of Erwinia carotovora. A terrestrial microcosm system for use in GEM risk assessment studies was developed for use in assessing alterations of microbial structure and functionmore » that may be caused by introducing the engineered strain of E. carotovora. This strain is being developed for use as a biological control agent for plant soft rot. Parameters that were monitored included survival and intraspecific competition of E. carotovora, structural effects upon both total bacterial populations and numbers of selected bacterial genera, effects upon activities of dehydrogenase and alkaline phosphatase, effects upon soil nutrients, and potential for gene transfer into or out of the engineered strain.« less

A Brighter Side of the New Genetics

ERIC Educational Resources Information Center

Glowienka, Emerine

1975-01-01

Discusses the positive side of genetic technology advances and the implications for human beings, both from a sociological viewpoint and the point of view of a social philosopher. Genetic engineering, technology and counseling are discussed. (BR)

Oxidation of organic contaminants by manganese oxide geomedia for passive urban stormwater treatment systems.

PubMed

Grebel, Janel E; Charbonnet, Joseph A; Sedlak, David L

2016-01-01

To advance cost-effective strategies for removing trace organic contaminants from urban runoff, the feasibility of using manganese oxides as a geomedia amendment in engineered stormwater infiltration systems to oxidize organic contaminants was evaluated. Ten representative organic chemicals that have previously been detected in urban stormwater were evaluated for reactivity in batch experiments with birnessite. With respect to reactivity, contaminants could be classified as: highly reactive (e.g., bisphenol A), moderately reactive (e.g., diuron) and unreactive (e.g., tris(2-chloro-1-propyl)phosphate). Bisphenol A and diuron reacted with birnessite to produce a suite of products, including ring-cleavage products for bisphenol A and partially dechlorinated products for diuron. Columns packed with manganese oxide-coated sand were used evaluate design parameters for an engineered infiltration system, including necessary contact times for effective treatment, as well as the impacts of stormwater matrix variables, such as solution pH, concentration of natural organic matter and major anions and cations. The manganese oxide geomedia exhibited decreased reactivity when organic contaminants were oxidized, especially in the presence of divalent cations, bicarbonate, and natural organic matter. Under typical conditions, the manganese oxides are expected to retain their reactivity for 25 years. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Simple Interactive Introduction to Teaching Genetic Engineering

ERIC Educational Resources Information Center

Child, Paula

2013-01-01

In the UK, at key stage 4, students aged 14-15 studying GCSE Core Science or Unit 1 of the GCSE Biology course are required to be able to describe the process of genetic engineering to produce bacteria that can produce insulin. The simple interactive introduction described in this article allows students to consider the problem, devise a model and…

77 FR 41351 - Bayer CropScience LP; Availability of a Finding of No Significant Impact and a Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... an Extension of a Determination of Nonregulated Status of Cotton Genetically Engineered for Herbicide... to extend to cotton event T303-3, which has been genetically engineered to be tolerant to the... of TwinLink TM cotton (event T304-40). We are making available for public comment our finding of no...

[Vaccine application of recombinant herpesviruses].

PubMed

Yokoyama, N; Xuan, X; Mikami, T

2000-04-01

Recently, genetic engineering using recombinant DNA techniques has been applied to design new viral vaccines in order to reduce some problems which the present viral vaccines have. Up to now, many viruses have been investigated for development of recombinant attenuated vaccines or live viral vectors for delivery of foreign genes coding immunogenic antigens. In this article, we introduced the new vaccine strategy using genetically engineered herpesviruses.

De-Problematizing 'GMOs': Suggestions for Communicating about Genetic Engineering.

PubMed

Blancke, Stefaan; Grunewald, Wim; De Jaeger, Geert

2017-03-01

The public debates concerning genetic engineering (GE) involve many non-scientific issues. The ensuing complexity is one reason why biotechnologists are reluctant to become involved. By sharing our personal experiences in science communication and suggesting ways to de-problematize GE, we aim to inspire our colleagues to engage with the public. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria by gas chromatography-mass spectrometry.

PubMed

Guan, Wenna; Zhao, Hui; Lu, Xuefeng; Wang, Cong; Yang, Menglong; Bai, Fali

2011-11-11

Simple and rapid quantitative determination of fatty-acid-based biofuels is greatly important for the study of genetic engineering progress for biofuels production by microalgae. Ideal biofuels produced from biological systems should be chemically similar to petroleum, like fatty-acid-based molecules including free fatty acids, fatty acid methyl esters, fatty acid ethyl esters, fatty alcohols and fatty alkanes. This study founded a gas chromatography-mass spectrometry (GC-MS) method for simultaneous quantification of seven free fatty acids, nine fatty acid methyl esters, five fatty acid ethyl esters, five fatty alcohols and three fatty alkanes produced by wild-type Synechocystis PCC 6803 and its genetically engineered strain. Data obtained from GC-MS analyses were quantified using internal standard peak area comparisons. The linearity, limit of detection (LOD) and precision (RSD) of the method were evaluated. The results demonstrated that fatty-acid-based biofuels can be directly determined by GC-MS without derivation. Therefore, rapid and reliable quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria can be achieved using the GC-MS method founded in this work. Copyright © 2011 Elsevier B.V. All rights reserved.

Challenges and Advances for Genetic Engineering of Non-model Bacteria and Uses in Consolidated Bioprocessing

PubMed Central

Yan, Qiang; Fong, Stephen S.

2017-01-01

Metabolic diversity in microorganisms can provide the basis for creating novel biochemical products. However, most metabolic engineering projects utilize a handful of established model organisms and thus, a challenge for harnessing the potential of novel microbial functions is the ability to either heterologously express novel genes or directly utilize non-model organisms. Genetic manipulation of non-model microorganisms is still challenging due to organism-specific nuances that hinder universal molecular genetic tools and translatable knowledge of intracellular biochemical pathways and regulatory mechanisms. However, in the past several years, unprecedented progress has been made in synthetic biology, molecular genetics tools development, applications of omics data techniques, and computational tools that can aid in developing non-model hosts in a systematic manner. In this review, we focus on concerns and approaches related to working with non-model microorganisms including developing molecular genetics tools such as shuttle vectors, selectable markers, and expression systems. In addition, we will discuss: (1) current techniques in controlling gene expression (transcriptional/translational level), (2) advances in site-specific genome engineering tools [homologous recombination (HR) and clustered regularly interspaced short palindromic repeats (CRISPR)], and (3) advances in genome-scale metabolic models (GSMMs) in guiding design of non-model species. Application of these principles to metabolic engineering strategies for consolidated bioprocessing (CBP) will be discussed along with some brief comments on foreseeable future prospects. PMID:29123506

Safe genetically engineered plants

NASA Astrophysics Data System (ADS)

Rosellini, D.; Veronesi, F.

2007-10-01

The application of genetic engineering to plants has provided genetically modified plants (GMPs, or transgenic plants) that are cultivated worldwide on increasing areas. The most widespread GMPs are herbicide-resistant soybean and canola and insect-resistant corn and cotton. New GMPs that produce vaccines, pharmaceutical or industrial proteins, and fortified food are approaching the market. The techniques employed to introduce foreign genes into plants allow a quite good degree of predictability of the results, and their genome is minimally modified. However, some aspects of GMPs have raised concern: (a) control of the insertion site of the introduced DNA sequences into the plant genome and of its mutagenic effect; (b) presence of selectable marker genes conferring resistance to an antibiotic or an herbicide, linked to the useful gene; (c) insertion of undesired bacterial plasmid sequences; and (d) gene flow from transgenic plants to non-transgenic crops or wild plants. In response to public concerns, genetic engineering techniques are continuously being improved. Techniques to direct foreign gene integration into chosen genomic sites, to avoid the use of selectable genes or to remove them from the cultivated plants, to reduce the transfer of undesired bacterial sequences, and make use of alternative, safer selectable genes, are all fields of active research. In our laboratory, some of these new techniques are applied to alfalfa, an important forage plant. These emerging methods for plant genetic engineering are briefly reviewed in this work.

Zinc-mediated transactivation of TrkB potentiates the hippocampal mossy fiber-CA3 pyramid synapse.

PubMed

Huang, Yang Z; Pan, Enhui; Xiong, Zhi-Qi; McNamara, James O

2008-02-28

The receptor tyrosine kinase, TrkB, is critical to diverse functions of the mammalian nervous system in health and disease. Evidence of TrkB activation during epileptogenesis in vivo despite genetic deletion of its prototypic neurotrophin ligands led us to hypothesize that a non-neurotrophin, the divalent cation zinc, can transactivate TrkB. We found that zinc activates TrkB through increasing Src family kinase activity by an activity-regulated mechanism independent of neurotrophins. One subcellular locale at which zinc activates TrkB is the postsynaptic density of excitatory synapses. Exogenous zinc potentiates the efficacy of the hippocampal mossy fiber (mf)-CA3 pyramid synapse by a TrkB-requiring mechanism. Long-term potentiation of this synapse is impaired by deletion of TrkB, inhibition of TrkB kinase activity, and by CaEDTA, a selective chelator of zinc. The activity-dependent activation of synaptic TrkB in a neurotrophin-independent manner provides a mechanism by which this receptor can regulate synaptic plasticity.

Measurement of the Mechanical Properties of Intact Collagen Fibrils

NASA Astrophysics Data System (ADS)

Mercedes, H.; Heim, A.; Matthews, W. G.; Koob, T.

2006-03-01

Motivated by the genetic disorder Ehlers-Danlos syndrome (EDS), in which proper collagen synthesis is interrupted, we are investigating the structural and mechanical properties of collagen fibrils. The fibrous glycoprotein collagen is the most abundant protein found in the human body and plays a key role in the extracellular matrix of the connective tissue, the properties of which are altered in EDS. We have selected as our model system the collagen fibrils of the sea cucumber dermis, a naturally mutable tissue. This system allows us to work with native fibrils which have their proteoglycan complement intact, something that is not possible with reconstituted mammalian collagen fibrils. Using atomic force microscopy, we measure, as a function of the concentration of divalent cations, the fibril diameter, its response to force loading, and the changes in its rigidity. Through these experiments, we will shed light on the mechanisms which control the properties of the sea cucumber dermis and hope to help explain the altered connective tissue extracellular matrix properties associated with EDS.

Progress in Metabolic Engineering of Saccharomyces cerevisiae

PubMed Central

Nevoigt, Elke

2008-01-01

Summary: The traditional use of the yeast Saccharomyces cerevisiae in alcoholic fermentation has, over time, resulted in substantial accumulated knowledge concerning genetics, physiology, and biochemistry as well as genetic engineering and fermentation technologies. S. cerevisiae has become a platform organism for developing metabolic engineering strategies, methods, and tools. The current review discusses the relevance of several engineering strategies, such as rational and inverse metabolic engineering, evolutionary engineering, and global transcription machinery engineering, in yeast strain improvement. It also summarizes existing tools for fine-tuning and regulating enzyme activities and thus metabolic pathways. Recent examples of yeast metabolic engineering for food, beverage, and industrial biotechnology (bioethanol and bulk and fine chemicals) follow. S. cerevisiae currently enjoys increasing popularity as a production organism in industrial (“white”) biotechnology due to its inherent tolerance of low pH values and high ethanol and inhibitor concentrations and its ability to grow anaerobically. Attention is paid to utilizing lignocellulosic biomass as a potential substrate. PMID:18772282

Genetic Engineering: A Possible Strategy for Protein-Energy Malnutrition Regulation.

PubMed

Guleria, Praveen; Kumar, Vineet; Guleria, Shiwani

2017-12-01

Protein-energy malnutrition (PEM) has adversely affected the generations of developing countries. It is a syndrome that in severity causes death. PEM generally affects infants of 1-5 age group. This manifestation is maintained till adulthood in the form of poor brain and body development. The developing nations are continuously making an effort to curb PEM. However, it is still a prime concern as it was in its early years of occurrence. Transgenic crops with high protein and enhanced nutrient content have been successfully developed. Present article reviews the studies documenting genetic engineering-mediated improvement in the pulses, cereals, legumes, fruits and other crop plants in terms of nutritional value, stress tolerance, longevity and productivity. Such genetically engineered crops can be used as a possible remedial tool to eradicate PEM.

Cell transplantation and genetic engineering: new approaches to cardiac pathology.

PubMed

Leor, Jonathan; Barbash, Israel M

2003-10-01

The remarkable progress in experimental cell transplantation, stem cell biology and genetic engineering promise new therapy and hopefully a cure for patients with end stage heart failure. Engineering of viable cardiac grafts with the potential to grow and remodel will provide new solutions to the serious problems of heart donor shortage. The ability to replace the injured heart muscle will have a dramatic influence on medicine, especially with the increasing number of patients with heart failure. This innovative research, now tested in human patients, still faces significant problems that need to be solved before it can be considered as an established therapeutic tool. The present review will focus on selected topics related to the promise and obstacles associated with cell transplantation, with and without genetic manipulation, for myocardial repair.

Genetically engineered mouse models for epithelial ovarian cancer: are we there yet?

PubMed

Howell, Viive M

2014-03-01

The development of preclinical spontaneous genetically engineered mouse models (GEMMs) requires an understanding of the genetic basis of the human disease. Such robust models have proven invaluable for increasing understanding of human malignancies as well as identifying new biomarkers and testing new therapies for these diseases. While GEMMs have been reported for ovarian cancer, the majority have proven disappointing overall in their recapitulation of paired genetic and histological features especially for serous ovarian epithelial cancer. This review describes GEMMs for ovarian cancer, in particular, high grade serous ovarian cancer and assesses these in light of recent changes in our understanding of the human malignancy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Recent Advances in Algal Genetic Tool Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

R. Dahlin, Lukas; T. Guarnieri, Michael

The goal of achieving cost-effective biofuels and bioproducts derived from algal biomass will require improvements along the entire value chain, including identification of robust, high-productivity strains and development of advanced genetic tools. Though there have been modest advances in development of genetic systems for the model alga Chlamydomonas reinhardtii, progress in development of algal genetic tools, especially as applied to non-model algae, has generally lagged behind that of more commonly utilized laboratory and industrial microbes. This is in part due to the complex organellar structure of algae, including robust cell walls and intricate compartmentalization of target loci, as well asmore » prevalent gene silencing mechanisms, which hinder facile utilization of conventional genetic engineering tools and methodologies. However, recent progress in global tool development has opened the door for implementation of strain-engineering strategies in industrially-relevant algal strains. Here, we review recent advances in algal genetic tool development and applications in eukaryotic microalgae.« less

Recent Advances in Algal Genetic Tool Development

DOE PAGES

R. Dahlin, Lukas; T. Guarnieri, Michael

2016-06-24

The goal of achieving cost-effective biofuels and bioproducts derived from algal biomass will require improvements along the entire value chain, including identification of robust, high-productivity strains and development of advanced genetic tools. Though there have been modest advances in development of genetic systems for the model alga Chlamydomonas reinhardtii, progress in development of algal genetic tools, especially as applied to non-model algae, has generally lagged behind that of more commonly utilized laboratory and industrial microbes. This is in part due to the complex organellar structure of algae, including robust cell walls and intricate compartmentalization of target loci, as well asmore » prevalent gene silencing mechanisms, which hinder facile utilization of conventional genetic engineering tools and methodologies. However, recent progress in global tool development has opened the door for implementation of strain-engineering strategies in industrially-relevant algal strains. Here, we review recent advances in algal genetic tool development and applications in eukaryotic microalgae.« less

Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain

PubMed Central

Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Micklem, Chris N.; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S.; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

2016-01-01

Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae. Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology. PMID:27247386

Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain.

PubMed

Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Abbott, James; Micklem, Chris N; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

2016-06-14

Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology.

Biomimetic self-templating optical structures fabricated by genetically engineered M13 bacteriophage.

PubMed

Kim, Won-Geun; Song, Hyerin; Kim, Chuntae; Moon, Jong-Sik; Kim, Kyujung; Lee, Seung-Wuk; Oh, Jin-Woo

2016-11-15

Here, we describe a highly sensitive and selective surface plasmon resonance sensor system by utilizing self-assembly of genetically engineered M13 bacteriophage. About 2700 copies of genetically expressed peptide copies give superior selectivity and sensitivity to M13 phage-based SPR sensor. Furthermore, the sensitivity of the M13 phage-based SPR sensor was enhanced due to the aligning of receptor matrix in specific direction. Incorporation of specific binding peptide (His Pro Gln: HPQ) gives M13 bacteriophage high selectivity for the streptavidin. Our M13 phage-based SPR sensor takes advantage of simplicity of self-assembly compared with relatively complex photolithography techniques or chemical conjugations. Additionally, designed structure which is composed of functionalized M13 bacteriophage can simultaneously improve the sensitivity and selectivity of SPR sensor evidently. By taking advantages of the genetic engineering and self-assembly, we propose the simple method for fabricating novel M13 phage-based SPR sensor system which has a high sensitivity and high selectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

Biotechnology: History shapes German opinion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, P.

Some 80% of the Germany people harbor a deep mistrust of genetic engineering - a fact that the author blames in part on the crimes that took place during the Nazi era. In Germany, words such as genetic selection' echo the rhetoric of the Nazi era. The connection to this dark period becomes evident when critics use the term molecular Auschwitz' to describe gene technology. Nazi crimes nourished a broad and emotional prejudice against scientists and industrialists on the part of the Germany people. Nevertheless, Germany adopted regulatory legislation, and the first field test of genetically engineered plants took placemore » in 1990. While Germany hesitates, other European nations are moving ahead to evaluate proposals for the deliberate release of genetically engineered organisms. Before the debate in Germany can be moved from emotional to rational grounds, scientists, who have preferred the laboratory to the public forum, must become actively involved. Politicians must stimulate such a debate and defend the results.« less

A versatile modular vector system for rapid combinatorial mammalian genetics.

PubMed

Albers, Joachim; Danzer, Claudia; Rechsteiner, Markus; Lehmann, Holger; Brandt, Laura P; Hejhal, Tomas; Catalano, Antonella; Busenhart, Philipp; Gonçalves, Ana Filipa; Brandt, Simone; Bode, Peter K; Bode-Lesniewska, Beata; Wild, Peter J; Frew, Ian J

2015-04-01

Here, we describe the multiple lentiviral expression (MuLE) system that allows multiple genetic alterations to be introduced simultaneously into mammalian cells. We created a toolbox of MuLE vectors that constitute a flexible, modular system for the rapid engineering of complex polycistronic lentiviruses, allowing combinatorial gene overexpression, gene knockdown, Cre-mediated gene deletion, or CRISPR/Cas9-mediated (where CRISPR indicates clustered regularly interspaced short palindromic repeats) gene mutation, together with expression of fluorescent or enzymatic reporters for cellular assays and animal imaging. Examples of tumor engineering were used to illustrate the speed and versatility of performing combinatorial genetics using the MuLE system. By transducing cultured primary mouse cells with single MuLE lentiviruses, we engineered tumors containing up to 5 different genetic alterations, identified genetic dependencies of molecularly defined tumors, conducted genetic interaction screens, and induced the simultaneous CRISPR/Cas9-mediated knockout of 3 tumor-suppressor genes. Intramuscular injection of MuLE viruses expressing oncogenic H-RasG12V together with combinations of knockdowns of the tumor suppressors cyclin-dependent kinase inhibitor 2A (Cdkn2a), transformation-related protein 53 (Trp53), and phosphatase and tensin homolog (Pten) allowed the generation of 3 murine sarcoma models, demonstrating that genetically defined autochthonous tumors can be rapidly generated and quantitatively monitored via direct injection of polycistronic MuLE lentiviruses into mouse tissues. Together, our results demonstrate that the MuLE system provides genetic power for the systematic investigation of the molecular mechanisms that underlie human diseases.

Fluorescent genetic barcoding in mammalian cells for enhanced multiplexing capabilities in flow cytometry.

PubMed

Smurthwaite, Cameron A; Hilton, Brett J; O'Hanlon, Ryan; Stolp, Zachary D; Hancock, Bryan M; Abbadessa, Darin; Stotland, Aleksandr; Sklar, Larry A; Wolkowicz, Roland

2014-01-01

The discovery of the green fluorescent protein from Aequorea victoria has revolutionized the field of cell and molecular biology. Since its discovery a growing panel of fluorescent proteins, fluorophores and fluorescent-coupled staining methodologies, have expanded the analytical capabilities of flow cytometry. Here, we exploit the power of genetic engineering to barcode individual cells with genes encoding fluorescent proteins. For genetic engineering, we utilize retroviral technology, which allows for the expression of ectopic genetic information in a stable manner in mammalian cells. We have genetically barcoded both adherent and nonadherent cells with different fluorescent proteins. Multiplexing power was increased by combining both the number of distinct fluorescent proteins, and the fluorescence intensity in each channel. Moreover, retroviral expression has proven to be stable for at least a 6-month period, which is critical for applications such as biological screens. We have shown the applicability of fluorescent barcoded multiplexing to cell-based assays that rely themselves on genetic barcoding, or on classical staining protocols. Fluorescent genetic barcoding gives the cell an inherited characteristic that distinguishes it from its counterpart. Once cell lines are developed, no further manipulation or staining is required, decreasing time, nonspecific background associated with staining protocols, and cost. The increasing number of discovered and/or engineered fluorescent proteins with unique absorbance/emission spectra, combined with the growing number of detection devices and lasers, increases multiplexing versatility, making fluorescent genetic barcoding a powerful tool for flow cytometry-based analysis. © 2013 International Society for Advancement of Cytometry.

Automated multiplex genome-scale engineering in yeast

PubMed Central

Si, Tong; Chao, Ran; Min, Yuhao; Wu, Yuying; Ren, Wen; Zhao, Huimin

2017-01-01

Genome-scale engineering is indispensable in understanding and engineering microorganisms, but the current tools are mainly limited to bacterial systems. Here we report an automated platform for multiplex genome-scale engineering in Saccharomyces cerevisiae, an important eukaryotic model and widely used microbial cell factory. Standardized genetic parts encoding overexpression and knockdown mutations of >90% yeast genes are created in a single step from a full-length cDNA library. With the aid of CRISPR-Cas, these genetic parts are iteratively integrated into the repetitive genomic sequences in a modular manner using robotic automation. This system allows functional mapping and multiplex optimization on a genome scale for diverse phenotypes including cellulase expression, isobutanol production, glycerol utilization and acetic acid tolerance, and may greatly accelerate future genome-scale engineering endeavours in yeast. PMID:28469255

Generation of genetically-engineered animals using engineered endonucleases.

PubMed

Lee, Jong Geol; Sung, Young Hoon; Baek, In-Jeoung

2018-05-17

The key to successful drug discovery and development is to find the most suitable animal model of human diseases for the preclinical studies. The recent emergence of engineered endonucleases is allowing for efficient and precise genome editing, which can be used to develop potentially useful animal models for human diseases. In particular, zinc finger nucleases, transcription activator-like effector nucleases, and the clustered regularly interspaced short palindromic repeat systems are revolutionizing the generation of diverse genetically-engineered experimental animals including mice, rats, rabbits, dogs, pigs, and even non-human primates that are commonly used for preclinical studies of the drug discovery. Here, we describe recent advances in engineered endonucleases and their application in various laboratory animals. We also discuss the importance of genome editing in animal models for more closely mimicking human diseases.

Genetic Engineering of Mesenchymal Stem Cells for Regenerative Medicine.

PubMed

Nowakowski, Adam; Walczak, Piotr; Janowski, Miroslaw; Lukomska, Barbara

2015-10-01

Mesenchymal stem cells (MSCs), which can be obtained from various organs and easily propagated in vitro, are one of the most extensively used types of stem cells and have been shown to be efficacious in a broad set of diseases. The unique and highly desirable properties of MSCs include high migratory capacities toward injured areas, immunomodulatory features, and the natural ability to differentiate into connective tissue phenotypes. These phenotypes include bone and cartilage, and these properties predispose MSCs to be therapeutically useful. In addition, MSCs elicit their therapeutic effects by paracrine actions, in which the metabolism of target tissues is modulated. Genetic engineering methods can greatly amplify these properties and broaden the therapeutic capabilities of MSCs, including transdifferentiation toward diverse cell lineages. However, cell engineering can also affect safety and increase the cost of therapy based on MSCs; thus, the advantages and disadvantages of these procedures should be discussed. In this review, the latest applications of genetic engineering methods for MSCs with regenerative medicine purposes are presented.

Genetic and metabolic engineering of microorganisms for the development of new flavor compounds from terpenic substrates.

PubMed

Bution, Murillo L; Molina, Gustavo; Abrahão, Meissa R E; Pastore, Gláucia M

2015-01-01

Throughout human history, natural products have been the basis for the discovery and development of therapeutics, cosmetic and food compounds used in industry. Many compounds found in natural organisms are rather difficult to chemically synthesize and to extract in large amounts, and in this respect, genetic and metabolic engineering are playing an increasingly important role in the production of these compounds, such as new terpenes and terpenoids, which may potentially be used to create aromas in industry. Terpenes belong to the largest class of natural compounds, are produced by all living organisms and play a fundamental role in human nutrition, cosmetics and medicine. Recent advances in systems biology and synthetic biology are allowing us to perform metabolic engineering at the whole-cell level, thus enabling the optimal design of microorganisms for the efficient production of drugs, cosmetic and food additives. This review describes the recent advances made in the genetic and metabolic engineering of the terpenes pathway with a particular focus on systems biotechnology.

Site-Specific Genome Engineering in Human Pluripotent Stem Cells.

PubMed

Merkert, Sylvia; Martin, Ulrich

2016-06-24

The possibility to generate patient-specific induced pluripotent stem cells (iPSCs) offers an unprecedented potential of applications in clinical therapy and medical research. Human iPSCs and their differentiated derivatives are tools for diseases modelling, drug discovery, safety pharmacology, and toxicology. Moreover, they allow for the engineering of bioartificial tissue and are promising candidates for cellular therapies. For many of these applications, the ability to genetically modify pluripotent stem cells (PSCs) is indispensable, but efficient site-specific and safe technologies for genetic engineering of PSCs were developed only recently. By now, customized engineered nucleases provide excellent tools for targeted genome editing, opening new perspectives for biomedical research and cellular therapies.

Engineered probiotic Escherichia coli can eliminate and prevent Pseudomonas aeruginosa gut infection in animal models

PubMed Central

Hwang, In Young; Koh, Elvin; Wong, Adison; March, John C.; Bentley, William E.; Lee, Yung Seng; Chang, Matthew Wook

2017-01-01

Bacteria can be genetically engineered to kill specific pathogens or inhibit their virulence. We previously developed a synthetic genetic system that allows a laboratory strain of Escherichia coli to sense and kill Pseudomonas aeruginosa in vitro. Here, we generate a modified version of the system, including a gene encoding an anti-biofilm enzyme, and use the probiotic strain Escherichia coli Nissle 1917 as host. The engineered probiotic shows in vivo prophylactic and therapeutic activity against P. aeruginosa during gut infection in two animal models (Caenorhabditis elegans and mice). These findings support the further development of engineered microorganisms with potential prophylactic and therapeutic activities against gut infections. PMID:28398304

Engineering microbes for efficient production of chemicals

DOEpatents

Gong, Wei; Dole, Sudhanshu; Grabar, Tammy; Collard, Andrew Christopher; Pero, Janice G; Yocum, R Rogers

2015-04-28

This present invention relates to production of chemicals from microorganisms that have been genetically engineered and metabolically evolved. Improvements in chemical production have been established, and particular mutations that lead to those improvements have been identified. Specific examples are given in the identification of mutations that occurred during the metabolic evolution of a bacterial strain genetically engineered to produce succinic acid. This present invention also provides a method for evaluating the industrial applicability of mutations that were selected during the metabolic evolution for increased succinic acid production. This present invention further provides microorganisms engineered to have mutations that are selected during metabolic evolution and contribute to improved production of succinic acid, other organic acids and other chemicals of commercial interest.

Structural Insight into Inhibitor of Apoptosis Proteins Recognition by a Potent Divalent Smac-Mimetic

PubMed Central

Vachette, Patrice; Malvezzi, Francesca; Grassi, Serena; Lecis, Daniele; Delia, Domenico; Drago, Carmelo; Seneci, Pierfausto; Bolognesi, Martino; Mastrangelo, Eloise

2012-01-01

Genetic alterations enhancing cell survival and suppressing apoptosis are hallmarks of cancer that significantly reduce the efficacy of chemotherapy or radiotherapy. The Inhibitor of Apoptosis Protein (IAP) family hosts conserved proteins in the apoptotic pathway whose over-expression, frequently found in tumours, potentiates survival and resistance to anticancer agents. In humans, IAPs comprise eight members hosting one or more structural Baculoviral IAP Repeat (BIR) domains. Cellular IAPs (cIAP1 and 2) indirectly inhibit caspase-8 activation, and regulate both the canonical and the non-canonical NF-κB signaling pathways. In contrast to cIAPs, XIAP (X chromosome-linked Inhibitor of Apoptosis Protein) inhibits directly the effector caspases-3 and -7 through its BIR2 domain, and initiator caspase-9 through its BIR3 domain; molecular docking studies suggested that Smac/DIABLO antagonizes XIAP by simultaneously targeting both BIR2 and BIR3 domains. Here we report analytical gel filtration, crystallographic and SAXS experiments on cIAP1-BIR3, XIAP-BIR3 and XIAP-BIR2BIR3 domains, alone and in the presence of compound 9a, a divalent homodimeric Smac mimetic. 9a is shown to bind two BIR domains inter- (in the case of two BIR3) and intra-molecularly (in the case of XIAP-BIR2BIR3), with higher affinity for cIAP1-BIR3, relative to XIAP-BIR3. Despite the different crystal lattice packing, 9a maintains a right handed helical conformation in both cIAP1-BIR3 and XIAP-BIR3 crystals, that is likely conserved in solution as shown by SAXS data. Our structural results demonstrate that the 9a linker length, its conformational degrees of freedom and its hydrophobicity, warrant an overall compact structure with optimal solvent exposure of its two active moieties for IAPs binding. Our results show that 9a is a good candidate for pre-clinical and clinical studies, worth of further investigations in the field of cancer therapy. PMID:23166698

Pre-implantation diagnosis of aneuploidy by polar body and blastomere FISH analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Munne, S.; Cohen, J.; Grifo, J.

1994-09-01

For preimplantation genetic diagnosis (PGD) of aneuploidy in human in-vitro fertilization (IVF), two blastomeres per embryo should be analyzed to minimize errors caused by FISH and mosaicism. But the biopsy of two cells from an 8-cell embryo can be detrimental. This can be substituted by initial FISH analysis of the first polar body (PB) and subsequent single blastomere analysis. Simultaneous FISH analysis of chromosomes X, Y, 18, 13/21 was used for first polar body aneuploidy analysis. Normal divalents appeared as single-dotted signals corresponding to their two chromatids. We found that pre-division of chromatids increased dramatically with time in culture. Allmore » but three pre-division events involved separation of chromatids within the PB or the egg, with a total of two chromatids in each. We concluded that PB aneuploidy analysis is safe when performed within 6 hours after egg retrieval. For our first clinical case we chose a 39 year-old female carrier of an X-linked disease already selected for FISH pre-implantation diagnosis. Eight polar bodies from 12 eggs were analyzed: six showed a normal X181321 complement of divalents; one had an extra chromatid for 13/21 (egg {number_sign}8); and one had a missing chromatid for 13/21 (egg {number_sign}10). After insemination, six fertilized eggs developed into embryos, including egg {number_sign}10 but not egg {number_sign}8. At day 3 of development, a single blastomere per embryo was analyzed by FISH. According to the blastomere analysis, one embryo was haploid, one tetraploid. The two normal female embryos were replaced and pregnancy and CFS results are pending. These results suggest that this technique can be successfully applied for PGD of major aneuploidies in IVF patients over 35. In addition, it indicates that studies on pre-division should be performed on eggs within six hours of retrieval.« less

State-of-the-Art Opportunities. Hispanic Special Report: Careers in Engineering.

ERIC Educational Resources Information Center

Heller, Michele

1992-01-01

Although the demand for electrical, defense, and computer science engineers has dropped sharply, opportunities exist for Hispanics in computer communication and integration, miniaturization of electronic components, environmental, and genetic and biomedical engineering. Engineers should diversify their skills to adapt to the changing field. (KS)

Between myth and reality: genetically modified maize, an example of a sizeable scientific controversy.

PubMed

Wisniewski, Jean-Pierre; Frangne, Nathalie; Massonneau, Agnès; Dumas, Christian

2002-11-01

Maize is a major crop plant with essential agronomical interests and a model plant for genetic studies. With the development of plant genetic engineering technology, many transgenic strains of this monocotyledonous plant have been produced over the past decade. In particular, field-cultivated insect-resistant Bt-maize hybrids are at the centre of an intense debate between scientists and organizations recalcitrant to genetically modified organisms (GMOs). This debate, which addresses both safety and ethical aspects, has raised questions about the impact of genetically modified (GM) crops on the biodiversity of traditional landraces and on the environment. Here, we review some of the key points of maize genetic history as well as the methods used to stably transform this cereal. We describe the genetically engineered Bt-maizes available for field cultivation and we investigate the controversial reports on their impacts on non-target insects such as the monarch butterfly and on the flow of transgenes into Mexican maize landraces.

2006 Joint Chemical Biological, Radiological and Nuclear (CBRN) Conference and Exhibition

DTIC Science & Technology

2006-06-28

methods that might counter or cancel our current military advantages • Defeat terrorist networks • Defend homeland in depth • Prevent acquisition or...Systems approach to the detection of chemical and biological agents with a focus on genetically engineered organisms ( GMOs )/genetically engineered...and possessing breakthrough technological capabilities intended to supplant U.S. advantages in particular operational domains. (capsize our power

American chestnut: A test case for genetic engineering?

Treesearch

Leila Pinchot

2014-01-01

The thought of genetically engineered (GE) trees might conjure images of mutant trees with unnatural and invasive tendencies, but there is much more to the story. GE trees are a new reality that, like it or not, will probably be part of the future of forestry. The basic inclination of most Forest Guild stewards is to reject GE trees as violating our principle to...

Smart, Injury-Triggered Therapy for Ocular Trauma

DTIC Science & Technology

2015-10-01

attachment surgery. We genetically engineered “protease activity sensor” (PAS) as chimeric transmembrane protein that can respond to increase in...results or key outcomes We genetically engineered “protease activity sensor” (PAS) as chimeric transmembrane protein that can respond to increase in...6 A B Fig. 1. The effects of ionomycin on the shedding of chimeric fractalkine constructs from HEK293 cells in vitro. (A

Katherine J. Chou | NREL

Science.gov Websites

J. Chou Photo of Katherine J. Chou Katherine Chou Microbial Physiology & Engineering , Clostridium thermocellum, through metabolic engineering. "Biological Electron Transfer and Catalysis principles governing substrate utilization. "Advance Biofuels from Cellulose via Genetic Engineering of

Collagen mimetic peptide engineered M13 bacteriophage for collagen targeting and imaging in cancer.

PubMed

Jin, Hyo-Eon; Farr, Rebecca; Lee, Seung-Wuk

2014-11-01

Collagens are over-expressed in various human cancers and subsequently degraded and denatured by proteolytic enzymes, thus making them a target for diagnostics and therapeutics. Genetically engineered bacteriophage (phage) is a promising candidate for the development of imaging or therapeutic materials for cancer collagen targeting due to its promising structural features. We genetically engineered M13 phages with two functional peptides, collagen mimetic peptide and streptavidin binding peptide, on their minor and major coat proteins, respectively. The resulting engineered phage functions as a therapeutic or imaging material to target degraded and denatured collagens in cancerous tissues. We demonstrated that the engineered phages are able to target and label abnormal collagens expressed on A549 human lung adenocarcinoma cells after the conjugation with streptavidin-linked fluorescent agents. Our engineered collagen binding phage could be a useful platform for abnormal collagen imaging and drug delivery in various collagen-related diseases. Published by Elsevier Ltd.

Domesticated, Genetically Engineered, and Wild Plant Relatives Exhibit Unintended Phenotypic Differences: A Comparative Meta-Analysis Profiling Rice, Canola, Maize, Sunflower, and Pumpkin

PubMed Central

Hernández-Terán, Alejandra; Wegier, Ana; Benítez, Mariana; Lira, Rafael; Escalante, Ana E.

2017-01-01

Agronomic management of plants is a powerful evolutionary force acting on their populations. The management of cultivated plants is carried out by the traditional process of human selection or plant breeding and, more recently, by the technologies used in genetic engineering (GE). Even though crop modification through GE is aimed at specific traits, it is possible that other non-target traits can be affected by genetic modification due to the complex regulatory processes of plant metabolism and development. In this study, we conducted a meta-analysis profiling the phenotypic consequences of plant breeding and GE, and compared modified cultivars with wild relatives in five crops of global economic and cultural importance: rice, maize, canola, sunflower, and pumpkin. For these five species, we analyzed the literature with documentation of phenotypic traits that are potentially related to fitness for the same species in comparable conditions. The information was analyzed to evaluate whether the different processes of modification had influenced the phenotype in such a way as to cause statistical differences in the state of specific phenotypic traits or grouping of the organisms depending on their genetic origin [wild, domesticated with genetic engineering (domGE), and domesticated without genetic engineering (domNGE)]. In addition, we tested the hypothesis that, given that transgenic plants are a construct designed to impact, in many cases, a single trait of the plant (e.g., lepidopteran resistance), the phenotypic differences between domGE and domNGE would be either less (or inexistent) than between the wild and domesticated relatives (either domGE or domNGE). We conclude that (1) genetic modification (either by selective breeding or GE) can be traced phenotypically when comparing wild relatives with their domesticated relatives (domGE and domNGE) and (2) the existence and the magnitude of the phenotypic differences between domGE and domNGE of the same crop suggest consequences of genetic modification beyond the target trait(s). PMID:29259610

Advances in the Engineering of the Gene Editing Enzymes and the Genomes: Understanding and Handling the Off-Target Effects of CRISPR/Cas9.

PubMed

Yin, Yufang; Wang, Qian; Xiao, Li; Wang, Fengjiao; Song, Zhuo; Zhou, Cuilan; Liu, Xuan; Xing, Chungen; He, Nongyue; Li, Kai; Feng, Yan; Zhang, Jia

2018-03-01

In the past decades, significant progresses have been achieved in genetic engineering of nucleases. Among the genetically engineered nucleases, zinc finger nucleases, transcription activator-like (TAL) effector nucleases, and CRIPSPR/Cas9 system form a new field of gene editing. The gene editing efficiency or targeting effect and the off-target effect are the two major determinant factors in evaluating the usefulness of a new enzyme. Engineering strategies in improving these gene editing enzymes, particularly in minimizing their off-target effects, are the focus of this paper. Examples of using these genetically engineered enzymes in genome modification are discussed in order to better understand the requirement of engineering efforts in obtaining more powerful and useful gene editing enzymes. In addition, the identification of naturally existed anti-Cas proteins has been employed in minimizing off-target effects. Considering the future application in human gene therapy, optimization of these well recognized gene editing enzymes and exploration of more novel enzymes are both required. Before people find an ideal gene editing system having virtually no off-target effect, technologies used to screen and identify off-target effects are of importance in clinical trials employing gene therapy.

The mismeasure of machine: Synthetic biology and the trouble with engineering metaphors.

PubMed

Boudry, Maarten; Pigliucci, Massimo

2013-12-01

The scientific study of living organisms is permeated by machine and design metaphors. Genes are thought of as the "blueprint" of an organism, organisms are "reverse engineered" to discover their functionality, and living cells are compared to biochemical factories, complete with assembly lines, transport systems, messenger circuits, etc. Although the notion of design is indispensable to think about adaptations, and engineering analogies have considerable heuristic value (e.g., optimality assumptions), we argue they are limited in several important respects. In particular, the analogy with human-made machines falters when we move down to the level of molecular biology and genetics. Living organisms are far more messy and less transparent than human-made machines. Notoriously, evolution is an opportunistic tinkerer, blindly stumbling on "designs" that no sensible engineer would come up with. Despite impressive technological innovation, the prospect of artificially designing new life forms from scratch has proven more difficult than the superficial analogy with "programming" the right "software" would suggest. The idea of applying straightforward engineering approaches to living systems and their genomes-isolating functional components, designing new parts from scratch, recombining and assembling them into novel life forms-pushes the analogy with human artifacts beyond its limits. In the absence of a one-to-one correspondence between genotype and phenotype, there is no straightforward way to implement novel biological functions and design new life forms. Both the developmental complexity of gene expression and the multifarious interactions of genes and environments are serious obstacles for "engineering" a particular phenotype. The problem of reverse-engineering a desired phenotype to its genetic "instructions" is probably intractable for any but the most simple phenotypes. Recent developments in the field of bio-engineering and synthetic biology reflect these limitations. Instead of genetically engineering a desired trait from scratch, as the machine/engineering metaphor promises, researchers are making greater strides by co-opting natural selection to "search" for a suitable genotype, or by borrowing and recombining genetic material from extant life forms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ionic configuration of copper ferrimanganites Cu 0.5Mn xFe 2.5- xO 4

NASA Astrophysics Data System (ADS)

Lenglet, M.; Kasperek, J.; Hannoyer, B.; Lopitaux, J.; d'Huysser, A.; Tellier, J. C.

1992-06-01

Mössbauer spectrometry, neutron diffraction, XANES, and XPS have led to the determination of the cation distributions of the system Cu 0.5Mn xFe 2.5- xO 4 (0≤ x≤1.5). The three cations are present in both tetrahedral and octahedral sites, and the relative number of Fe ions on A- and B-sites remains nearly constant in the whole range of x. It appears that for x≤0.5 manganese is divalent and copper is in its two oxidation states. For x>0.5 copper and iron are respectively divalent and trivalent; the manganese is in +2 and +3 oxydation states.

Graphene oxide papers modified by divalent ions-enhancing mechanical properties via chemical cross-linking.

PubMed

Park, Sungjin; Lee, Kyoung-Seok; Bozoklu, Gulay; Cai, Weiwei; Nguyen, Sonbinh T; Ruoff, Rodney S

2008-03-01

Significant enhancement in mechanical stiffness (10-200%) and fracture strength (approximately 50%) of graphene oxide paper, a novel paperlike material made from individual graphene oxide sheets, can be achieved upon modification with a small amount (less than 1 wt %) of Mg(2+) and Ca(2+). These results can be readily rationalized in terms of the chemical interactions between the functional groups of the graphene oxide sheets and the divalent metals ions. While oxygen functional groups on the basal planes of the sheets and the carboxylate groups on the edges can both bond to Mg(2+) and Ca(2+), the main contribution to mechanical enhancement of the paper comes from the latter.

Metal-dependent inhibition of HIV-1 integrase by 5CITEP inhibitor: A theoretical QM/MM approach

NASA Astrophysics Data System (ADS)

do Nascimento, Josenaide P.; Araújo Silva, José Rogério; Lameira, Jerônimo; Alves, Cláudio N.

2013-09-01

HIV-1 integrase (IN) is a potential target for developing drugs against AIDS. In this letter, QM/MM approach was used to study the inhibition of IN by 5CITEP inhibitor in presence of divalent cations (Mg2+ or Mn2+). In addition, the main interactions occurring in 5CITEP-IN complex and the influence of divalent cations (Mg2+ or Mn2+) in enzymatic inhibition were investigated using B3LYP/6-31+G(d,p)/MM. The results suggest that the Asp64, Asp116 and four crystal water molecules plays a crucial role in cation (Mg2+ or Mn2+) coordination sphere.

Growth and characterization of divalent transition metal ions doped zinc hydrogen phosphate single crystals

NASA Astrophysics Data System (ADS)

D'Souza, Delma; Jagannatha, N.; Nagaraja, K. P.; Rohith, P. S.; Pradeepkumar, K. V.

2018-05-01

Zinc hydrogen phosphate (ZnHP) single crystal co-doped with divalent transition metal ions Cobalt (Co2+) and Cadmium (Cd2+) is grown by gel technique in silica hydro gel media. The presence of Co2+ and Cd2+ dopants in the ZnHP crystal was confirmed by Energy Dispersive X-ray Analysis (EDAX).FTIR spectra of the grown crystal depict the stretching and bending vibration of PO4 units, water of crystallization and metal-oxygen bonds. Powder XRD analysis reveals that the grown crystal belongs to monoclinic system with spacegroup P 21. The thermal stability of the grown crystal is rectified from TG-DSC studies.

Experiential Engineering through iGEM--An Undergraduate Summer Competition in Synthetic Biology

ERIC Educational Resources Information Center

Mitchell, Rudolph; Dori, Yehudit Judy; Kuldell, Natalie H.

2011-01-01

Unlike students in other engineering disciplines, undergraduates in biological engineering typically have limited opportunity to develop design competencies, and even fewer chances to implement their designed projects. The international Genetically Engineered Machines (iGEM) competition is a student Synthetic Biology competition that, in 2009,…

Consumer perception of risk associated with eating genetically engineered soybeans is less in the presence of a perceived consumer benefit.

PubMed

Brown, J Lynne; Ping, Yanchao

2003-02-01

To determine whether perceived benefit alters personal risk perception associated with eating genetically engineered soybeans, consumer desire for labeling, preferred phrase on a label symbol, and desired information in an educational brochure. Comparison of responses of two consumer groups who completed one of two survey versions. One hundred fifty supermarket shoppers, age 21 years and older, for each survey or n=300 total. Focus groups and a pilot test were used to develop the final survey in which consumers read a description of a genetically engineered soybean with either no obvious consumer benefit or an obvious consumer benefit and then completed a set of attitude questions and evaluated a voluntary label design and educational brochure content. Main outcome measures were mean opinion scores of personal risk and desire for labeling and ranking of desired label phrase and brochure topics. Chi;(2) and t Tests were used. Consumers reading about the soybean with obvious consumer benefit were significantly more comfortable eating these than those reading about the soybean with no obvious consumer benefit (2.9+/-1.1 vs 3.4+/-1.0, respectively; P

Microfluidics and microbial engineering.

PubMed

Kou, Songzi; Cheng, Danhui; Sun, Fei; Hsing, I-Ming

2016-02-07

The combination of microbial engineering and microfluidics is synergistic in nature. For example, microfluidics is benefiting from the outcome of microbial engineering and many reported point-of-care microfluidic devices employ engineered microbes as functional parts for the microsystems. In addition, microbial engineering is facilitated by various microfluidic techniques, due to their inherent strength in high-throughput screening and miniaturization. In this review article, we firstly examine the applications of engineered microbes for toxicity detection, biosensing, and motion generation in microfluidic platforms. Secondly, we look into how microfluidic technologies facilitate the upstream and downstream processes of microbial engineering, including DNA recombination, transformation, target microbe selection, mutant characterization, and microbial function analysis. Thirdly, we highlight an emerging concept in microbial engineering, namely, microbial consortium engineering, where the behavior of a multicultural microbial community rather than that of a single cell/species is delineated. Integrating the disciplines of microfluidics and microbial engineering opens up many new opportunities, for example in diagnostics, engineering of microbial motors, development of portable devices for genetics, high throughput characterization of genetic mutants, isolation and identification of rare/unculturable microbial species, single-cell analysis with high spatio-temporal resolution, and exploration of natural microbial communities.

Reverse-engineering the genetic circuitry of a cancer cell with predicted intervention in chronic lymphocytic leukemia.

PubMed

Vallat, Laurent; Kemper, Corey A; Jung, Nicolas; Maumy-Bertrand, Myriam; Bertrand, Frédéric; Meyer, Nicolas; Pocheville, Arnaud; Fisher, John W; Gribben, John G; Bahram, Seiamak

2013-01-08

Cellular behavior is sustained by genetic programs that are progressively disrupted in pathological conditions--notably, cancer. High-throughput gene expression profiling has been used to infer statistical models describing these cellular programs, and development is now needed to guide orientated modulation of these systems. Here we develop a regression-based model to reverse-engineer a temporal genetic program, based on relevant patterns of gene expression after cell stimulation. This method integrates the temporal dimension of biological rewiring of genetic programs and enables the prediction of the effect of targeted gene disruption at the system level. We tested the performance accuracy of this model on synthetic data before reverse-engineering the response of primary cancer cells to a proliferative (protumorigenic) stimulation in a multistate leukemia biological model (i.e., chronic lymphocytic leukemia). To validate the ability of our method to predict the effects of gene modulation on the global program, we performed an intervention experiment on a targeted gene. Comparison of the predicted and observed gene expression changes demonstrates the possibility of predicting the effects of a perturbation in a gene regulatory network, a first step toward an orientated intervention in a cancer cell genetic program.

Gene targeting and cloning in pigs using fetal liver derived cells.

PubMed

Waghmare, Sanjeev K; Estrada, Jose; Reyes, Luz; Li, Ping; Ivary, Bess; Sidner, Richard A; Burlak, Chris; Tector, A Joseph

2011-12-01

Since there are no pig embryonic stem cells, pig genetic engineering is done in fetal fibroblasts that remain totipotent for only 3 to 5 wk. Nuclear donor cells that remain totipotent for longer periods of time would facilitate complicated genetic engineering in pigs. The goal of this study was to test the feasibility of using fetal liver-derived cells (FLDC) to perform gene targeting, and create a genetic knockout pig. FLDC were isolated and processed using a human liver stem cell protocol. Single copy α-1,3-galactosyl transferase knockout (GTKO) FLDCs were created using electroporation and neomycin resistant colonies were screened using PCR. Homozygous GTKO cells were created through loss of heterozygosity mutations in single GTKO FLDCs. Double GTKO FLDCs were used in somatic cell nuclear transfer (SCNT) to create GTKO pigs. FLDCs grew for more than 80 population doublings, maintaining normal karyotype. Gene targeting and loss of heterozygosity mutations produced homozygous GTKO FLDCs. FLDCs used in SCNT gave rise to homozygous GTKO pigs. FDLCs can be used in gene targeting and SCNT to produce genetically modified pigs. The increased life span in culture compared to fetal fibroblasts may facilitate genetic engineering in the pig. Copyright © 2011 Elsevier Inc. All rights reserved.

Nature of Science and Decision-Making

NASA Astrophysics Data System (ADS)

Khishfe, Rola

2012-01-01

The study investigated the relationship of nature of science (NOS) instruction and students' decision-making (DM) related to a controversial socioscientific issue about genetically modified food. Participants were ninth-grade students in four intact sections (two regulars and two honors) in a public high school in the Midwest. All four groups were taught by their regular science teacher. The treatment comprised a four-week unit about genetic engineering. Two groups (one regular and one honors), referred to as comparison groups, received instruction in genetic engineering and how to formulate arguments and make decisions related to this controversial issue. The other two groups (one regular and one honors), referred to as treatment groups, received instruction in genetic engineering and how to apply NOS aspects as they formulate arguments and make decisions in relation to this controversial issue. Chi-square analyses showed significant differences between the comparison and the treatment groups in relation to the understandings of four NOS aspects. There were no differences in their decisions, but there were differences in their DM factors in the context of the controversial socioscientific issue about genetically modified food. These results are discussed in light of the relationship between students' understandings of NOS and their DM related to controversial socioscientific issues.

Genetic Design Automation: engineering fantasy or scientific renewal?

PubMed Central

Lux, Matthew W.; Bramlett, Brian W.; Ball, David A.; Peccoud, Jean

2013-01-01

Synthetic biology aims to make genetic systems more amenable to engineering, which has naturally led to the development of Computer-Aided Design (CAD) tools. Experimentalists still primarily rely on project-specific ad-hoc workflows instead of domain-specific tools, suggesting that CAD tools are lagging behind the front line of the field. Here, we discuss the scientific hurdles that have limited the productivity gains anticipated from existing tools. We argue that the real value of efforts to develop CAD tools is the formalization of genetic design rules that determine the complex relationships between genotype and phenotype. PMID:22001068

Enhanced energy transport in genetically engineered excitonic networks.

PubMed

Park, Heechul; Heldman, Nimrod; Rebentrost, Patrick; Abbondanza, Luigi; Iagatti, Alessandro; Alessi, Andrea; Patrizi, Barbara; Salvalaggio, Mario; Bussotti, Laura; Mohseni, Masoud; Caruso, Filippo; Johnsen, Hannah C; Fusco, Roberto; Foggi, Paolo; Scudo, Petra F; Lloyd, Seth; Belcher, Angela M

2016-02-01

One of the challenges for achieving efficient exciton transport in solar energy conversion systems is precise structural control of the light-harvesting building blocks. Here, we create a tunable material consisting of a connected chromophore network on an ordered biological virus template. Using genetic engineering, we establish a link between the inter-chromophoric distances and emerging transport properties. The combination of spectroscopy measurements and dynamic modelling enables us to elucidate quantum coherent and classical incoherent energy transport at room temperature. Through genetic modifications, we obtain a significant enhancement of exciton diffusion length of about 68% in an intermediate quantum-classical regime.

Genetic engineering of microbial pesticides

Treesearch

Bruce C. Carlton

1985-01-01

Recent advances in genetics and molecular biology make possible the cloning and genetic manipulation of genes for insecticidal activities from natural insect pathogens. Using recombinant DNA methods and site-directed mutagenesis of specific gene regions, production of new and improved biorationals should be possible.

Awareness of Societal Issues among High School Biology Teachers Teaching Genetics

ERIC Educational Resources Information Center

Lazarowitz, Reuven; Bloch, Ilit

2005-01-01

The purpose of this study was to investigate how aware high school biology teachers are of societal issues (values, moral, ethic, and legal issues) while teaching genetics, genetics engineering, molecular genetics, human heredity, and evolution. The study includes a short historical review of World War II atrocities during the Holocaust when…

Escherichia Coli--Key to Modern Genetics.

ERIC Educational Resources Information Center

Bregegere, Francois

1982-01-01

Mid-nineteenth century work by Mendel on plant hybrids and by Pasteur on fermentation gave birth by way of bacterial genetics to modern-day molecular biology. The bacterium Escherichia Coli has occupied a key position in genetic studies leading from early gene identification with DNA to current genetic engineering using recombinant DNA technology.…

Genetically engineered livestock: ethical use for food and medical models.

PubMed

Garas, Lydia C; Murray, James D; Maga, Elizabeth A

2015-01-01

Recent advances in the production of genetically engineered (GE) livestock have resulted in a variety of new transgenic animals with desirable production and composition changes. GE animals have been generated to improve growth efficiency, food composition, and disease resistance in domesticated livestock species. GE animals are also used to produce pharmaceuticals and as medical models for human diseases. The potential use of these food animals for human consumption has prompted an intense debate about food safety and animal welfare concerns with the GE approach. Additionally, public perception and ethical concerns about their use have caused delays in establishing a clear and efficient regulatory approval process. Ethically, there are far-reaching implications of not using genetically engineered livestock, at a detriment to both producers and consumers, as use of this technology can improve both human and animal health and welfare.

[The use of genetic angiogenesis inductors in surgical treatment of chronic lower limb ischemia].

PubMed

Gavrilenko, A V; Voronov, D A; Bochkov, N P

2013-01-01

The efficacy and safety of gene-engineering recombinant constructions with endothelial growth factor gene and angiogenin for the treatment of the chronic lower limb ischemia were studied. 134 patients were included in prospective controlled study. The main group, who received both traditional treatment and genetic therapy, consisted of 74 patients. The rest 60 patients were included into the control group. Of 74 patients from the main group, genetic therapy was used together with conservative means in 39 patients and with reconstructive vascular operations in 35 patients. The gene-engineering angiogenesis stimulation therapy proved to be effective and safe. The combination of angiogenesis genetic stimulation with reconstructive vascular surgery demonstrated significantly better results, then monotherapy.

Genomic analysis of a xylose operon and characterization of novel xylose isomerase and xylulokinase from Bacillus coagulans NL01.

PubMed

Zheng, Zhaojuan; Lin, Xi; Jiang, Ting; Ye, Weihua; Ouyang, Jia

2016-08-01

To investigate the xylose operon and properties of xylose isomerase and xylulokinase in Bacillus coagulans that can effectively ferment xylose to lactic acid. The xylose operon is widely present in B. coagulans. It is composed of four putative ORFs. Novel xylA and xylB from B. coagulans NL01 were cloned and expressed in Escherichia coli. Sequence of xylose isomerase was more conserved than that of xylulokinase. Both the enzymes exhibited maximum activities at pH 7-8 but with a high temperature maximum of 80-85 °C, divalent metal ion was prerequisite for their activation. Xylose isomerase and xylulokinase were most effectively activated by Ni(2+) and Co(2+), respectively. Genomic analysis of xylose operon has contributed to understanding xylose metabolism in B. coagulans and the novel xylose isomerase and xylulokinase might provide new alternatives for metabolic engineering of other strains to improve their fermentation performance on xylose.

Multiscale Interfacial Strategy to Engineer Mixed Metal-Oxide Anodes toward Enhanced Cycling Efficiency.

PubMed

Ma, Yue; Tai, Cheuk-Wai; Li, Shaowen; Edström, Kristina; Wei, Bingqing

2018-06-13

Interconnected macro/mesoporous structures of mixed metal oxide (MMO) are developed on nickel foam as freestanding anodes for Li-ion batteries. The sustainable production is realized via a wet chemical etching process with bio-friendly chemicals. By means of divalent iron doping during an in situ recrystallization process, the as-developed MMO anodes exhibit enhanced levels of cycling efficiency. Furthermore, this atomic-scale modification coherently synergizes with the encapsulation layer across a micrometer scale. During this step, we develop a quasi-gel-state tri-copolymer, i.e., F127-resorcinol-melamine, as the N-doped carbon source to regulate the interfacial chemistry of the MMO electrodes. Electrochemical tests of the modified Fe x Ni 1- x O@NC-NiF anode in both half-cell and full-cell configurations unravel the favorable suppression of the irreversible capacity loss and satisfactory cyclability at the high rates. This study highlights a proof-of-concept modification strategy across multiple scales to govern the interfacial chemical process of the electrodes toward better reversibility.

An artificial interphase enables reversible magnesium chemistry in carbonate electrolytes.

PubMed

Son, Seoung-Bum; Gao, Tao; Harvey, Steve P; Steirer, K Xerxes; Stokes, Adam; Norman, Andrew; Wang, Chunsheng; Cresce, Arthur; Xu, Kang; Ban, Chunmei

2018-05-01

Magnesium-based batteries possess potential advantages over their lithium counterparts. However, reversible Mg chemistry requires a thermodynamically stable electrolyte at low potential, which is usually achieved with corrosive components and at the expense of stability against oxidation. In lithium-ion batteries the conflict between the cathodic and anodic stabilities of the electrolytes is resolved by forming an anode interphase that shields the electrolyte from being reduced. This strategy cannot be applied to Mg batteries because divalent Mg 2+ cannot penetrate such interphases. Here, we engineer an artificial Mg 2+ -conductive interphase on the Mg anode surface, which successfully decouples the anodic and cathodic requirements for electrolytes and demonstrate highly reversible Mg chemistry in oxidation-resistant electrolytes. The artificial interphase enables the reversible cycling of a Mg/V 2 O 5 full-cell in the water-containing, carbonate-based electrolyte. This approach provides a new avenue not only for Mg but also for other multivalent-cation batteries facing the same problems, taking a step towards their use in energy-storage applications.

An artificial interphase enables reversible magnesium chemistry in carbonate electrolytes

NASA Astrophysics Data System (ADS)

Son, Seoung-Bum; Gao, Tao; Harvey, Steve P.; Steirer, K. Xerxes; Stokes, Adam; Norman, Andrew; Wang, Chunsheng; Cresce, Arthur; Xu, Kang; Ban, Chunmei

2018-05-01

Magnesium-based batteries possess potential advantages over their lithium counterparts. However, reversible Mg chemistry requires a thermodynamically stable electrolyte at low potential, which is usually achieved with corrosive components and at the expense of stability against oxidation. In lithium-ion batteries the conflict between the cathodic and anodic stabilities of the electrolytes is resolved by forming an anode interphase that shields the electrolyte from being reduced. This strategy cannot be applied to Mg batteries because divalent Mg2+ cannot penetrate such interphases. Here, we engineer an artificial Mg2+-conductive interphase on the Mg anode surface, which successfully decouples the anodic and cathodic requirements for electrolytes and demonstrate highly reversible Mg chemistry in oxidation-resistant electrolytes. The artificial interphase enables the reversible cycling of a Mg/V2O5 full-cell in the water-containing, carbonate-based electrolyte. This approach provides a new avenue not only for Mg but also for other multivalent-cation batteries facing the same problems, taking a step towards their use in energy-storage applications.

Iron homeostasis and toxicity in retinal degeneration.

PubMed

He, Xining; Hahn, Paul; Iacovelli, Jared; Wong, Robert; King, Chih; Bhisitkul, Robert; Massaro-Giordano, Mina; Dunaief, Joshua L

2007-11-01

Iron is essential for many metabolic processes but can also cause damage. As a potent generator of hydroxyl radical, the most reactive of the free radicals, iron can cause considerable oxidative stress. Since iron is absorbed through diet but not excreted except through menstruation, total body iron levels buildup with age. Macular iron levels increase with age, in both men and women. This iron has the potential to contribute to retinal degeneration. Here we present an overview of the evidence suggesting that iron may contribute to retinal degenerations. Intraocular iron foreign bodies cause retinal degeneration. Retinal iron buildup resulting from hereditary iron homeostasis disorders aceruloplasminemia, Friedreich's ataxia, and panthothenate kinase-associated neurodegeneration cause retinal degeneration. Mice with targeted mutation of the iron exporter ceruloplasmin have age-dependent retinal iron overload and a resulting retinal degeneration with features of age-related macular degeneration (AMD). Post mortem retinas from patients with AMD have more iron and the iron carrier transferrin than age-matched controls. Over the past 10 years much has been learned about the intricate network of proteins involved in iron handling. Many of these, including transferrin, transferrin receptor, divalent metal transporter-1, ferritin, ferroportin, ceruloplasmin, hephaestin, iron-regulatory protein, and histocompatibility leukocyte antigen class I-like protein involved in iron homeostasis (HFE) have been found in the retina. Some of these proteins have been found in the cornea and lens as well. Levels of the iron carrier transferrin are high in the aqueous and vitreous humors. The functions of these proteins in other tissues, combined with studies on cultured ocular tissues, genetically engineered mice, and eye exams on patients with hereditary iron diseases provide clues regarding their ocular functions. Iron may play a role in a broad range of ocular diseases, including glaucoma, cataract, AMD, and conditions causing intraocular hemorrhage. While iron deficiency must be prevented, the therapeutic potential of limiting iron-induced ocular oxidative damage is high. Systemic, local, or topical iron chelation with an expanding repertoire of drugs has clinical potential.

Genetic Engineering of Algae for Enhanced Biofuel Production ▿

PubMed Central

Radakovits, Randor; Jinkerson, Robert E.; Darzins, Al; Posewitz, Matthew C.

2010-01-01

There are currently intensive global research efforts aimed at increasing and modifying the accumulation of lipids, alcohols, hydrocarbons, polysaccharides, and other energy storage compounds in photosynthetic organisms, yeast, and bacteria through genetic engineering. Many improvements have been realized, including increased lipid and carbohydrate production, improved H2 yields, and the diversion of central metabolic intermediates into fungible biofuels. Photosynthetic microorganisms are attracting considerable interest within these efforts due to their relatively high photosynthetic conversion efficiencies, diverse metabolic capabilities, superior growth rates, and ability to store or secrete energy-rich hydrocarbons. Relative to cyanobacteria, eukaryotic microalgae possess several unique metabolic attributes of relevance to biofuel production, including the accumulation of significant quantities of triacylglycerol; the synthesis of storage starch (amylopectin and amylose), which is similar to that found in higher plants; and the ability to efficiently couple photosynthetic electron transport to H2 production. Although the application of genetic engineering to improve energy production phenotypes in eukaryotic microalgae is in its infancy, significant advances in the development of genetic manipulation tools have recently been achieved with microalgal model systems and are being used to manipulate central carbon metabolism in these organisms. It is likely that many of these advances can be extended to industrially relevant organisms. This review is focused on potential avenues of genetic engineering that may be undertaken in order to improve microalgae as a biofuel platform for the production of biohydrogen, starch-derived alcohols, diesel fuel surrogates, and/or alkanes. PMID:20139239

Conditions for success of engineered underdominance gene drive systems.

PubMed

Edgington, Matthew P; Alphey, Luke S

2017-10-07

Engineered underdominance is one of a number of different gene drive strategies that have been proposed for the genetic control of insect vectors of disease. Here we model a two-locus engineered underdominance based gene drive system that is based on the concept of mutually suppressing lethals. In such a system two genetic constructs are introduced, each possessing a lethal element and a suppressor of the lethal at the other locus. Specifically, we formulate and analyse a population genetics model of this system to assess when different combinations of release strategies (i.e. single or multiple releases of both sexes or males only) and genetic systems (i.e. bisex lethal or female-specific lethal elements and different strengths of suppressors) will give population replacement or fail to do so. We anticipate that results presented here will inform the future design of engineered underdominance gene drive systems as well as providing a point of reference regarding release strategies for those looking to test such a system. Our discussion is framed in the context of genetic control of insect vectors of disease. One of several serious threats in this context are Aedes aegypti mosquitoes as they are the primary vectors of dengue viruses. However, results are also applicable to Ae. aegypti as vectors of Zika, yellow fever and chikungunya viruses and also to the control of a number of other insect species and thereby of insect-vectored pathogens. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Adhesion kinetics of viable Cryptosporidium parvum oocysts to quartz surfaces.

PubMed

Kuznar, Zachary A; Elimelech, Menachem

2004-12-15

The transport and deposition (adhesion) kinetics of viable Cryptosporidium parvum oocysts onto ultrapure quartz surfaces in a radial stagnation point flow system were investigated. Utilizing an optical microscope and an image-capturing device enabled real time observation of oocyst deposition behavior onto the quartz surface in solutions containing either monovalent (KCl) or divalent (CaCl2) salts. Results showed a significantly lower oocyst deposition rate in the presence of a monovalent salt compared to a divalent salt. With a monovalent salt, oocyst deposition rates and corresponding attachment efficiencies were relatively low, even at high KCl concentrations where Derjaguin-Landau-Verwey-Overbeek (DLVO) theory predicts the absence of an electrostatic energy barrier. On the other hand, in the presence of a divalent salt, oocyst deposition rates increased continuously as the salt concentration was increased over the entire range of ionic strengths investigated. The unusually low deposition rate in a monovalent salt solution is attributed to "electrosteric" repulsion between the Cryptosporidium oocyst and the quartz surface, most likely due to proteins on the oocyst surface that extend into the solution. It is further proposed that specific binding of calcium ions to the oocyst surface functional groups results in charge neutralization and conformational changes of surface proteins that significantly reduce electrosteric repulsion.

Cation Effects on the Electron-Acceptor Side of Photosystem II.

PubMed

Khan, Sahr; Sun, Jennifer S; Brudvig, Gary W

2015-06-18

The normal pathway of electron transfer on the electron-acceptor side of photosystem II (PSII) involves electron transfer from quinone A, QA, to quinone B, QB. It is possible to redirect electrons from QA(-) to water-soluble Co(III) complexes, which opens a new avenue for harvesting electrons from water oxidation by immobilization of PSII on electrode surfaces. Herein, the kinetics of electron transfer from QA(-) to [Co(III)(terpy)2](3+) (terpy = 2,2';6',2″-terpyridine) are investigated with a spectrophotometric assay revealing that the reaction follows Michaelis-Menten saturation kinetics, is inhibited by cations, and is not affected by variation of the QA reduction potential. A negatively charged site on the stromal surface of the PSII protein complex, composed of glutamic acid residues near QA, is hypothesized to bind cations, especially divalent cations. The cations are proposed to tune the redox properties of QA through electrostatic interactions. These observations may thus explain the molecular basis of the effect of divalent cations like Ca(2+), Sr(2+), Mg(2+), and Zn(2+) on the redox properties of the quinones in PSII, which has previously been attributed to long-range conformational changes propagated from divalent cations binding to the Ca(II)-binding site in the oxygen-evolving complex on the lumenal side of the PSII complex.

Study on improving viscosity of polymer solution based on complex reaction

NASA Astrophysics Data System (ADS)

Sun, G.; Li, D.; Zhang, D.; Xu, T. H.

2018-05-01

The current status of polymer flooding Technology on high salinity oil reservoir is not ideal. A method for increasing the viscosity of polymer solutions is urgently needed. This paper systematically studied the effect of ions with different mass concentrations on the viscosity of polymer solutions. Based on the theory of complex reaction, a countermeasure of increasing viscosity of polymer solution under conditions of high salinity reservoir was proposed. The results show that Ca2+ and Mg2+ have greater influence on the solution viscosity than K+ and Na+. When the concentration of divalent ions increases from 0 mg/L to 80 mg/L, the viscosity of the polymer solution decreases from 210 mPa·s to 38.6 mPa·s. The viscosity of the polymer solution prepared from the sewage treated with the Na2C2O4 increased by 25.3%. Atomic force microscopy test results show that Na2C2O4 can effectively shield the divalent metal ions, so that the polymer molecules in the solution stretch more, thereby increasing the solution viscosity. Atomic force microscopy test results show that Na2C2O4 can effectively shield the divalent metal ions, so that the polymer molecules in the solution stretch more, thereby increasing the solution viscosity.

Phosphorus-31 and carbon-13 nuclear magnetic resonance studies of divalent cation binding to phosphatidylserine membranes. Use of cobalt as a paramagnetic probe

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLaughlin, A.C.

1982-01-01

The paramagnetic divalent cation cobalt has large and well-understood effects on NMR signals from ligands bound in the first coordination sphere, i.e., inner-sphere ligands, and the authors have used these effects to identify divalent cation binding sites at the surface of phosphatidylserine membranes. /sup 31/P NMR results show that 13% of the bound cobalt ions are involved in inner-sphere complexes with the phosphodiester group, while /sup 13/C NMR results show that 54% of the bound cobalt ions are involved in unidentate inner sphere complexes with the carboxyl group. No evidence is found for cobalt binding to the carbonyl groups, butmore » proton release studies suggest that 32% of the bound cobalt ions are involved in chelate complexes that contain both the carboxyl and the amine groups. All of the bound cobalt ions can thus be accounted for in terms of inner sphere complexes with the phosphodiester group or the carboxyl group. They suggest that the unidentate inner-sphere complex between cobalt and the carboxyl group of phosphatidylserine and the inner-sphere complex between cobalt and the phosphodiester group of phosphatidylserine provide reasonable models for complexes between alkaline earth cations and phosphatidylserine membranes.« less

Phosphorus-31 and carbon-13 nuclear magnetic resonance studies of divalent cation binding to phosphatidylserine membranes: use of cobalt as a paramagnetic probe

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLaughlin, A.C.

1982-09-28

The paramagnetic divalent cation cobalt has large and well-understood effects on NMR signals from ligands bound in the first coordination sphere, i.e., inner-sphere ligands, and we have used these effects to identify divalent cation binding sites at the surface of phosphatidylserine membranes. /sup 31/P NMR results show that 13% of the bound cobalt ions are involved in inner-sphere complexes with the phosphodiester group, while /sup 13/C NMR results show that 54% of the bound cobalt ions are involved in unidentate inner sphere complexes with the carboxyl group. No evidence is found for cobalt binding to the carbonyl groups, but protonmore » release studies suggest that 32% of the bound cobalt ions are involved in chelate complexes that contain both the carboxyl and the amine groups. All (i.e., 13% + 54% + 32% = 99%) of the bound cobalt ions can thus be accounted for in terms of inner sphere complexes with the phosphodiester group or the carboxyl group. We suggest that the unidentate inner-sphere complex between cobalt and the carboxyl group of phosphatidylserine and the inner-sphere complex between cobalt and the phosphodiester group of phosphatidylserine provide reasonable models for complexes between alkaline earth cations and phosphatidylserine membranes.« less

Struvite formation and decomposition characteristics for ammonia and phosphorus recovery: A review of magnesium-ammonia-phosphate interactions.

PubMed

Tansel, Berrin; Lunn, Griffin; Monje, Oscar

2018-03-01

Struvite (MgNH 4 PO 4 ·6H 2 O) forms in aqueous systems with high ammonia and phosphate concentrations. However, conditions that result into struvite formation are highly dependent on the ionic compositions, temperature, pH, and ion speciation characteristics. The primary ions involved in struvite formation have complex interactions and can form different crystals depending on the ionic levels, pH and temperature. Struvite as well as struvite analogues (with substitution of monovalent cations for NH 4 + or divalent cations for Mg 2+ ) as well as other crystals can form simultaneously and result in changes in crystal morphology during crystal growth. This review provides the results from experimental and theoretical studies on struvite formation and decomposition studies. Characteristics of NH 4 + or divalent cations for Mg 2+ were evaluated in comparison to monovalent and divalent ions for formation of struvite and its analogues. Struvite crystals forming in wastewater systems are likely to contain crystals other than struvite due to ionic interactions, pH changes, temperature effects and clustering of ions during nucleation and crystal growth. Decomposition of struvite occurs following a series of reactions depending on the rate of heating, temperature and availability of water during heating. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ionic requirements for membrane-glass adhesion and giga seal formation in patch-clamp recording.

PubMed

Priel, Avi; Gil, Ziv; Moy, Vincent T; Magleby, Karl L; Silberberg, Shai D

2007-06-01

Patch-clamp recording has revolutionized the study of ion channels, transporters, and the electrical activity of small cells. Vital to this method is formation of a tight seal between glass recording pipette and cell membrane. To better understand seal formation and improve practical application of this technique, we examine the effects of divalent ions, protons, ionic strength, and membrane proteins on adhesion of membrane to glass and on seal resistance using both patch-clamp recording and atomic force microscopy. We find that H(+), Ca(2+), and Mg(2+) increase adhesion force between glass and membrane (lipid and cellular), decrease the time required to form a tight seal, and increase seal resistance. In the absence of H(+) (10(-10) M) and divalent cations (<10(-8) M), adhesion forces are greatly reduced and tight seals are not formed. H(+) (10(-7) M) promotes seal formation in the absence of divalent cations. A positive correlation between adhesion force and seal formation indicates that high resistance seals are associated with increased adhesion between membrane and glass. A similar ionic dependence of the adhesion of lipid membranes and cell membranes to glass indicates that lipid membranes without proteins are sufficient for the action of ions on adhesion.

Metabolic engineering of biosynthetic pathway for production of renewable biofuels.

PubMed

Singh, Vijai; Mani, Indra; Chaudhary, Dharmendra Kumar; Dhar, Pawan Kumar

2014-02-01

Metabolic engineering is an important area of research that involves editing genetic networks to overproduce a certain substance by the cells. Using a combination of genetic, metabolic, and modeling methods, useful substances have been synthesized in the past at industrial scale and in a cost-effective manner. Currently, metabolic engineering is being used to produce sufficient, economical, and eco-friendly biofuels. In the recent past, a number of efforts have been made towards engineering biosynthetic pathways for large scale and efficient production of biofuels from biomass. Given the adoption of metabolic engineering approaches by the biofuel industry, this paper reviews various approaches towards the production and enhancement of renewable biofuels such as ethanol, butanol, isopropanol, hydrogen, and biodiesel. We have also identified specific areas where more work needs to be done in the future.

EFFECTS OF 2,4-DICHLOROPHENOL, A METABOLITE OF A GENETICALLY ENGINEERED BACTERIUM, AND 2,4-DICHLOROPHENOXYACETATE ON SOME MICROORGANISM-MEDIATED ECOLOGICAL PROCESSES IN SOIL

EPA Science Inventory

A genetically engineered microorganism, Pseudomonas putida PPO301 (pRO103), and the plasmidless parent strain, PPO301, were added at approximately 10 7 CFU/g of soil amended with 500 ppm of 2,4-dichlorophenoxyacete (2,4-D)(500 ug/g). he degradation of 2,4-D and the accumulation o...

Monsanto may bypass NIH in microbe test.

PubMed

Sun, Marjorie

1985-01-11

The Monsanto Company is planning to ask the Environmental Protection Agency for clearance to field test a genetically engineered microbial pesticide, bypassing the traditional approval process of the National Institutes of Health. Although only federally funded institutions are required to obtain NIH approval for genetic engineering tests, Monsanto is the first company to bypass the NIH regulatory process, which has become mired in a lawsuit brought by Jeremy Rifkin.

Genetically Engineered Natural Killer Cells as a Means for Adoptive Tumor Immunotherapy.

PubMed

Michen, Susanne; Temme, Achim

2016-01-01

Natural killer (NK) cells are lymphoid cells of the innate immune system; they stand at the first defense line against viruses and transformed cells. NK cells use an array of germline-encoded activating and inhibitory receptors that sense virus-infected cells or malignant cells displaying altered surface expression of activating and inhibitory NK cell ligands. They exert potent cytotoxic responses to cellular targets and thus are candidate effector cells for immunotherapy of cancer. In particular, the genetic engineering of NK cells with chimeric antigen receptors (CARs) against surface-expressed tumor-associated antigens (TAAs) seems promising. In the allogeneic context, gene-modified NK cells compared to T cells may be superior because they are short-lived effector cells and do not cause graft-versus-host disease. Furthermore, their anti-tumoral activity can be augmented by combinatorial use with therapeutic antibodies, chemotherapeutics, and radiation. Today, efforts are being undertaken for large-scale NK-cell expansion and their genetic engineering for adoptive cell transfer. With the recent advances in understanding the complex biological interactions that regulate NK cells, it is expected that the genetic engineering of NK cells and a combinatorial blockade of immune evasion mechanisms are required to exploit the full potential of NK-cell-based immunotherapies.

Unraveling the neurobiology of nicotine dependence using genetically engineered mice.

PubMed

Stoker, Astrid K; Markou, Athina

2013-08-01

This review article provides an overview of recent studies of nicotine dependence and withdrawal that used genetically engineered mice. Major progress has been made in recent years with mutant mice that have knockout and gain-of-function of specific neuronal nicotinic acetylcholine receptor (nAChR) subunit genes. Nicotine exerts its actions by binding to neuronal nAChRs that consist of five subunits. The different nAChR subunits that combine to compose a receptor determine the distinct pharmacological and kinetic properties of the specific nAChR. Recent findings in genetically engineered mice have indicated that while α4-containing and β2-containing nAChRs are involved in the acquisition of nicotine self-administration and initial stages of nicotine dependence, α7 homomeric nAChRs appear to be involved in the later stages of nicotine dependence. In the medial habenula, α5-containing, α3-containing, and β4-containing nAChRs were shown to be crucially important in the regulation of the aversive aspects of nicotine. Studies of the involvement of α6 nAChR subunits in nicotine dependence have only recently emerged. The use of genetically engineered mice continues to vastly improve our understanding of the neurobiology of nicotine dependence and withdrawal. Copyright © 2013 Elsevier Ltd. All rights reserved.

Volatile terpenoids: multiple functions, biosynthesis, modulation and manipulation by genetic engineering.

PubMed

Abbas, Farhat; Ke, Yanguo; Yu, Rangcai; Yue, Yuechong; Amanullah, Sikandar; Jahangir, Muhammad Muzammil; Fan, Yanping

2017-11-01

Terpenoids play several physiological and ecological functions in plant life through direct and indirect plant defenses and also in human society because of their enormous applications in the pharmaceutical, food and cosmetics industries. Through the aid of genetic engineering its role can by magnified to broad spectrum by improving genetic ability of crop plants, enhancing the aroma quality of fruits and flowers and the production of pharmaceutical terpenoids contents in medicinal plants. Terpenoids are structurally diverse and the most abundant plant secondary metabolites, playing an important role in plant life through direct and indirect plant defenses, by attracting pollinators and through different interactions between the plants and their environment. Terpenoids are also significant because of their enormous applications in the pharmaceutical, food and cosmetics industries. Due to their broad distribution and functional versatility, efforts are being made to decode the biosynthetic pathways and comprehend the regulatory mechanisms of terpenoids. This review summarizes the recent advances in biosynthetic pathways, including the spatiotemporal, transcriptional and post-transcriptional regulatory mechanisms. Moreover, we discuss the multiple functions of the terpene synthase genes (TPS), their interaction with the surrounding environment and the use of genetic engineering for terpenoid production in model plants. Here, we also provide an overview of the significance of terpenoid metabolic engineering in crop protection, plant reproduction and plant metabolic engineering approaches for pharmaceutical terpenoids production and future scenarios in agriculture, which call for sustainable production platforms by improving different plant traits.

Metabolic Engineering of Probiotic Saccharomyces boulardii.

PubMed

Liu, Jing-Jing; Kong, In Iok; Zhang, Guo-Chang; Jayakody, Lahiru N; Kim, Heejin; Xia, Peng-Fei; Kwak, Suryang; Sung, Bong Hyun; Sohn, Jung-Hoon; Walukiewicz, Hanna E; Rao, Christopher V; Jin, Yong-Su

2016-04-01

Saccharomyces boulardiiis a probiotic yeast that has been used for promoting gut health as well as preventing diarrheal diseases. This yeast not only exhibits beneficial phenotypes for gut health but also can stay longer in the gut than Saccharomyces cerevisiae Therefore, S. boulardiiis an attractive host for metabolic engineering to produce biomolecules of interest in the gut. However, the lack of auxotrophic strains with defined genetic backgrounds has hampered the use of this strain for metabolic engineering. Here, we report the development of well-defined auxotrophic mutants (leu2,ura3,his3, and trp1) through clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9-based genome editing. The resulting auxotrophic mutants can be used as a host for introducing various genetic perturbations, such as overexpression or deletion of a target gene, using existing genetic tools forS. cerevisiae We demonstrated the overexpression of a heterologous gene (lacZ), the correct localization of a target protein (red fluorescent protein) into mitochondria by using a protein localization signal, and the introduction of a heterologous metabolic pathway (xylose-assimilating pathway) in the genome ofS. boulardii We further demonstrated that human lysozyme, which is beneficial for human gut health, could be secreted by S. boulardii Our results suggest that more sophisticated genetic perturbations to improveS. boulardii can be performed without using a drug resistance marker, which is a prerequisite for in vivo applications using engineeredS. boulardii. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Genetic engineering and sustainable production of ornamentals: current status and future directions.

PubMed

Lütken, Henrik; Clarke, Jihong Liu; Müller, Renate

2012-07-01

Through the last decades, environmentally and health-friendly production methods and conscientious use of resources have become crucial for reaching the goal of a more sustainable plant production. Protection of the environment requires careful consumption of limited resources and reduction of chemicals applied during production of ornamental plants. Numerous chemicals used in modern plant production have negative impacts on human health and are hazardous to the environment. In Europe, several compounds have lost their approval and further legal restrictions can be expected. This review presents the more recent progress of genetic engineering in ornamental breeding, delivers an overview of the biological background of the used technologies and critically evaluates the usefulness of the strategies to obtain improved ornamental plants. First, genetic engineering is addressed as alternative to growth retardants, comprising recombinant DNA approaches targeting relevant hormone pathways, e.g. the gibberellic acid (GA) pathway. A reduced content of active GAs causes compact growth and can be facilitated by either decreased anabolism, increased catabolism or altered perception. Moreover, compactness can be accomplished by using a natural transformation approach without recombinant DNA technology. Secondly, metabolic engineering approaches targeting elements of the ethylene signal transduction pathway are summarized as a possible alternative to avoid the use of chemical ethylene inhibitors. In conclusion, molecular breeding approaches are dealt with in a way allowing a critical biological assessment and enabling the scientific community and public to put genetic engineering of ornamental plants into a perspective regarding their usefulness in plant breeding.

Can Man Control His Biological Evolution? A Symposium on Genetic Engineering. Man's Responsibility to His Future

ERIC Educational Resources Information Center

Hoagland, Hudson

1972-01-01

Biological evolution can be carried out in the laboratory. With new knowledge available in genetics, possibilities are raised that genetic characters can be transferred in the future to embryos according to a predetermined plan. (PS)

Metabolic engineering of yeast for production of fuels and chemicals.

PubMed

Nielsen, Jens; Larsson, Christer; van Maris, Antonius; Pronk, Jack

2013-06-01

Microbial production of fuels and chemicals from renewable carbohydrate feedstocks offers sustainable and economically attractive alternatives to their petroleum-based production. The yeast Saccharomyces cerevisiae offers many advantages as a platform cell factory for such applications. Already applied on a huge scale for bioethanol production, this yeast is easy to genetically engineer, its physiology, metabolism and genetics have been intensively studied and its robustness enables it to handle harsh industrial conditions. Introduction of novel pathways and optimization of its native cellular processes by metabolic engineering are rapidly expanding its range of cell-factory applications. Here we review recent scientific progress in metabolic engineering of S. cerevisiae for the production of bioethanol, advanced biofuels, and chemicals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Efficient engineering of a bacteriophage genome using the type I-E CRISPR-Cas system.

PubMed

Kiro, Ruth; Shitrit, Dror; Qimron, Udi

2014-01-01

The clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) system has recently been used to engineer genomes of various organisms, but surprisingly, not those of bacteriophages (phages). Here we present a method to genetically engineer the Escherichia coli phage T7 using the type I-E CRISPR-Cas system. T7 phage genome is edited by homologous recombination with a DNA sequence flanked by sequences homologous to the desired location. Non-edited genomes are targeted by the CRISPR-Cas system, thus enabling isolation of the desired recombinant phages. This method broadens CRISPR Cas-based editing to phages and uses a CRISPR-Cas type other than type II. The method may be adjusted to genetically engineer any bacteriophage genome.

The structure of ions and zwitterionic lipids regulates the charge of dipolar membranes.

PubMed

Szekely, Or; Steiner, Ariel; Szekely, Pablo; Amit, Einav; Asor, Roi; Tamburu, Carmen; Raviv, Uri

2011-06-21

In pure water, zwitterionic lipids form lamellar phases with an equilibrium water gap on the order of 2 to 3 nm as a result of the dominating van der Waals attraction between dipolar bilayers. Monovalent ions can swell those neutral lamellae by a small amount. Divalent ions can adsorb onto dipolar membranes and charge them. Using solution X-ray scattering, we studied how the structure of ions and zwitterionic lipids regulates the charge of dipolar membranes. We found that unlike monovalent ions that weakly interact with all of the examined dipolar membranes, divalent and trivalent ions adsorb onto membranes containing lipids with saturated tails, with an association constant on the order of ∼10 M(-1). One double bond in the lipid tail is sufficient to prevent divalent ion adsorption. We suggest that this behavior is due to the relatively loose packing of lipids with unsaturated tails that increases the area per lipid headgroup, enabling their free rotation. Divalent ion adsorption links two lipids and limits their free rotation. The ion-dipole interaction gained by the adsorption of the ions onto unsaturated membranes is insufficient to compensate for the loss of headgroup free-rotational entropy. The ion-dipole interaction is stronger for cations with a higher valence. Nevertheless, polyamines behave as monovalent ions near dipolar interfaces in the sense that they interact weakly with the membrane surface, whereas in the bulk their behavior is similar to that of multivalent cations. Advanced data analysis and comparison with theory provide insight into the structure and interactions between ion-induced regulated charged interfaces. This study models biologically relevant interactions between cell membranes and various ions and the manner in which the lipid structure governs those interactions. The ability to monitor these interactions creates a tool for probing systems that are more complex and forms the basis for controlling the interactions between dipolar membranes and charged proteins or biopolymers for encapsulation and delivery applications. © 2011 American Chemical Society

Divalent ions are potential permeating blockers of the non-selective NaK ion channel: combined QM and MD based investigations.

PubMed

Sadhu, Biswajit; Sundararajan, Mahesh; Bandyopadhyay, Tusar

2017-10-18

The bacterial NaK ion channel is distinctly different from other known ion channels due to its inherent non-selective feature. One of the unexplored and rather interesting features is its ability to permeate divalent metal ions (such as Ca 2+ and Ba 2+ ) and not monovalent alkali metal ions. Several intriguing questions about the energetics and structural aspects still remain unanswered. For instance, what causes Ca 2+ to permeate as well as block the selectivity filter (SF) of the NaK ion channel and act as a "permeating blocker"? How and at what energetic cost does another chemical congener, Sr 2+ , as well as Ba 2+ , a potent blocker of the K + ion channel, permeate through the SF of the NaK ion channel? Finally, how do their translocation energetics differ from those of monovalent ions such as K + ? Here, in an attempt to address these outstanding issues, we elucidate the structure, binding and selectivity of divalent ions (Ca 2+ , Sr 2+ and Ba 2+ ) as they permeate through the SF of the NaK ion channel using all-atom molecular dynamics simulations and density functional theory based calculations. We unveil mechanistic insight into this translocation event using well-tempered metadynamics simulations in a polarizable environment using the mean-field model of water and incorporating electronic continuum corrections for ions via charge rescaling. The results show that, akin to K + coordination, Sr 2+ and Ba 2+ bind at the SF in a very similar fashion and remain octa-coordinated at all sites. Interestingly, differing from its local hydration structure, Ca 2+ interacts with eight carbonyls to remain at the middle of the S3 site. Furthermore, the binding of divalent metals at SF binding sites is more favorable than the binding of K + . However, their permeation through the extracellular entrance faces a considerably higher energetic barrier compared to that for K + , which eventually manifests their inherent blocking feature.

Uptake of divalent ions (Mn+2 and Ca+2) by heat-set whey protein gels.

PubMed

Oztop, Mecit H; McCarthy, Kathryn L; McCarthy, Michael J; Rosenberg, Moshe

2012-02-01

Divalent salts are used commonly for gelation of polymer molecules. Calcium, Ca(+2), is one of the most common divalent ions that is used in whey protein gels. Manganese, Mn(+2), is also divalent, but paramagnetic, enhancing relaxation decay rates in magnetic resonance imaging (MRI) and can be used as a probe to understand the behavior of Ca(+2) in whey protein gels. The objective of this study was to investigate the diffusion of Ca(+2) and Mn(+2) ions in heat-set whey protein gels by using MRI and nuclear magnetic resonance (NMR) relaxometry. Whey protein gels were immersed in solutions containing MnCl(2) and CaCl(2) at neutral pH. Images obtained with gels immersed in MnCl(2) solution revealed a relaxation sink region in the gel's surface and the thickness of the region increased with time. These "no signal" regions in the MR images were attributed to uptake of Mn(+2) by the gel. Results obtained with CaCl(2) solution indicated that since Ca(+2) did not have the paramagnetic effect, the regions where Ca(+2) diffused into the gel exhibited a slight decrease in signal intensity. The relaxation spectrums exhibited 3 populations of protons, for gels immersed in MnCl(2) solution, and 2 populations for gels in CaCl(2) solution. No significant change in T(2) distributions was observed for the gels immersed in CaCl(2) solution. The results demonstrated that MRI and NMR relaxometry can be used to understand the diffusion of ions into the whey protein gel, which is useful for designing gels of different physical properties for controlled release applications. Design of food systems for delivery of bioactive compounds requires knowledge of diffusion rates and structure. Utilizing magnetic resonance imaging the diffusion rates of ions can be measured. Relaxation spectra could yield information concerning molecular interactions. © 2012 Institute of Food Technologists®

Spontaneous bacterial and fungal infections in genetically engineered mice: Is Escherichia coli an emerging pathogen in laboratory mouse?

PubMed

Benga, Laurentiu; Benten, W Peter M; Engelhardt, Eva; Gougoula, Christina; Sager, Martin

2015-01-01

The impact of particular microbes on genetically engineered mice depends on the genotype and the environment. Infections resulting in clinical disease have an obvious impact on animal welfare and experimentation. In this study, we investigated the bacterial and fungal aetiology of spontaneous clinical disease of infectious origin among the genetically engineered mice from our institution in relation to their genotype. A total of 63 mice belonging to 33 different mice strains, from severe immunodeficient to wild-type, were found to display infections as the primary cause leading to their euthanasia. The necropsies revealed abscesses localized subcutaneously as well as in the kidney, preputial glands, seminal vesicles, in the uterus, umbilicus or in the lung. In addition, pneumonia, endometritis and septicaemia cases were recorded. Escherichia coli was involved in 21 of 44 (47.72%) of the lesions of bacterial origin, whereas [Pasteurella] pneumotropica was isolated from 19 of 44 (43.18%) cases. The infections with the two agents mentioned above included three cases of mixed infection with both pathogens. Staphylococcus aureus was considered responsible for five of 44 (11.36%) cases whereas Enterobacter cloacae was found to cause lesions in two of 44 (4.54%) mice. Overall, 16 of the 44 (36.36%) cases of bacterial aetiology affected genetically engineered mice without any explicit immunodeficiency or wild-type strains. The remaining 19 cases of interstitial pneumonia were caused by Pneumocystis murina. In conclusion, the susceptibility of genetically modified mice to opportunistic infections has to be regarded with precaution, regardless of the type of genetic modification performed. Beside the classical opportunists, such as [Pasteurella] pneumotropica and Staphylococcus aureus, Escherichia coli should as well be closely monitored to evaluate whether it represents an emerging pathogen in the laboratory mouse.

The surface chemistry of multi-oxide silicates

NASA Astrophysics Data System (ADS)

Oelkers, Eric H.; Golubev, Sergey V.; Chairat, Claire; Pokrovsky, Oleg S.; Schott, Jacques

2009-08-01

The surface chemistry of natural wollastonite, diopside, enstatite, forsterite, and albite in aqueous solutions was characterized using both electrokinetic techniques and surface titrations performed for 20 min in batch reactors. Titrations performed in such reactors allow determination of both proton consumption and metal release from the mineral surface as a function of pH. The compositions, based on aqueous solution analysis, of all investigated surfaces vary dramatically with solution pH. Ca and Mg are preferentially released from the surfaces of all investigated divalent metal silicates at pH less than ˜8.5-10 but preferentially retained relative to silica at higher pH. As such, the surfaces of these minerals are Si-rich and divalent metal poor except in strongly alkaline solutions. The preferential removal of divalent cations from these surfaces is coupled to proton consumption. The number of protons consumed by the preferential removal of each divalent cation is pH independent but depends on the identity of the mineral; ˜1.5 protons are consumed by the preferential removal of each Ca atom from wollastonite, ˜3 protons are consumed by the preferential removal of each Mg or Ca atom from diopside or enstatite, and ˜4 protons are consumed by the preferential removal of each Mg from forsterite. These observations are interpreted to stem from the creation of additional 'internal' adsorption sites by the preferential removal of divalent metal cations which can be coupled to the condensation of partially detached Si. Similarly, Na and Al are preferentially removed from the albite surface at 2 > pH > 11; mass balance calculations suggest that three protons are consumed by the preferential removal of each Al atom from this surface over this entire pH range. Electrokinetic measurements on fresh mineral powders yield an isoelectric point (pH IEP) 2.6, 4.4, 3.0, 4.5, and <1, for wollastonite, diopside, enstatite, forsterite, and albite, respectively, consistent with the predominance of SiO 2 in the surface layer of all of these multi-oxide silicates at acidic pH. Taken together, these observations suggest fundamental differences between the surface chemistry of simple versus multi-oxide minerals including (1) a dependency of the number and identity of multi-oxide silicate surface sites on the aqueous solution composition, and (2) the dominant role of metal-proton exchange reactions on the reactivity of multi-oxide mineral surfaces including their dissolution rate variation with aqueous solution composition.

Valence of Ti, V, and Cr in Apollo 14 aluminous basalts 14053 and 14072

NASA Astrophysics Data System (ADS)

Simon, Steven B.; Sutton, Stephen R.

2017-09-01

The valences of Ti, V, and Cr in olivine and pyroxene, important indicators of the fO2 of the source region of their host rocks, can be readily measured nondestructively by XANES (X-ray absorption near edge structure) spectroscopy, but little such work has been done on lunar rocks, and there is some uncertainty regarding the presence of Ti3+ in lunar silicates and the redox state of the lunar mantle. This is the first study involving direct XANES measurement of valences of multivalent cations in lunar rocks. Because high alumina activity facilitates substitution of Ti cations into octahedral rather than tetrahedral sites in pyroxene and Ti3+ only enters octahedral sites, two aluminous basalts from Apollo 14, 14053 and 14072, were studied. Most pyroxene contains little or no detectable Ti3+, but in both samples relatively early, magnesian pyroxene was found that has Ti valences that are not within error of 4; in 14053, this component has an average Ti valence of 3.81 ± 0.06 (i.e., Ti3+/[Ti3+ + Ti4+ = 0.19]). This pyroxene has relatively low atomic Ti/Al ratios (<0.4) due to crystallization before plagioclase, contrary to the long-held belief that lunar pyroxene with Ti/Al > 0.5 contains Ti3+ and pyroxene with lower ratios does not. Later pyroxene, with lower Mg/Fe and higher Ti/Al ratios, has higher proportions of Ti (all Ti4+) in tetrahedral sites. All pyroxene analyzed contains divalent Cr, ranging from 15 to 30% of the Cr present, and all but one analysis spot contains divalent V, accounting for 0 to 40% (typically 20-30%) of the V present. Three analyses of olivine in 14053 do not show any Ti3+, but Ti valences in 14072 olivine range from 4 down to 3.70 ± 0.10. In 14053 olivine, 50% of the Cr and 60% of the V are divalent. In 14072 olivine, the divalent percentages are 20% for Cr and 20-60% for V. These results indicate significant proportions of divalent Cr and V and limited amounts of trivalent Ti in the parental melts, especially when crystal/liquid partitioning preferences are taken into account. These features are consistent with an fO2 closer to IW - 2 than to IW - 1. Apollo 15 basalt 15555, analyzed for comparison with A-14 materials, has olivine with strongly reduced Cr (Cr2+/(Cr2+ + Cr3+) 0.9). Basalts from different sites may record redox differences between source regions.

The multiple nucleotide-divalent cation binding modes of Saccharomyces cerevisiae CK2α indicate a possible co-substrate hydrolysis product (ADP/GDP) release pathway.

PubMed

Liu, Huihui; Wang, Hong; Teng, Maikun; Li, Xu

2014-02-01

CK2 is a ubiquitous and conserved protein kinase in eukaryotic organisms and is important in many biological processes. It is unique in maintaining constitutive activity and in using both ATP and GTP as phosphor donors. In this study, crystal structures of recombinant Saccharomyces cerevisiae CK2α (scCK2α) complexed with GMPPNP, ATP and AMPPN with either Mg2+ or Mn2+ as the coordinated divalent cation are presented. The overall structure of scCK2α shows high similarity to its homologous proteins by consisting of two domains with the co-substrate lying in the cleft between them. However, three characteristic features distinguish scCK2α from its homologues. Firstly, the Lys45-Glu53 and Arg48-Glu53 interactions in scCK2α lead Lys50 to adopt a unique conformation that is able to stabilize the γ-phosphate of the co-substrate, which makes the existence of the `essential divalent cation' not so essential. The multiple nucleotide-divalent cation binding modes of the active site of scCK2α are apparently different from the two-divalent-cation-occupied active site of Zea mays CK2α and human CK2α. Secondly, conformational change of Glu53 in scCK2α-AMPPN breaks its interaction with Lys45 and Arg48; as a result, the co-substrate binding pocket becomes more open. This may suggest a clue to a possible ADP/GDP-release pathway, because the NE1 atom of the Trp in the `DWG motif' of CK2α forms a hydrogen bond to the O atom of Leu212, which seems to make ADP release by means of the `DFG-in flip to DFG-out' model found in most eukaryotic protein kinases impossible. Coincidentally, two sulfate ions which may mimic two phosphate groups were captured by Arg161 and Lys197 around the pocket. Mutagenesis and biochemical experiments on R161A and K197A mutants support the above proposal. Finally, scCK2α is unique in containing an insertion region whose function had not been identified in previous research. It is found that the insertion region contributes to maintaining the constitutively active conformation of the scCK2α catalytic site, but does not participate in interaction with the regulatory subunits.

4f and 5d energy levels of the divalent and trivalent lanthanide ions in M{sub 2}Si{sub 5}N{sub 8} (M=Ca, Sr, Ba)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kate, O.M. ten, E-mail: o.m.tenkate@tudelft.nl; Energy Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5600MB Eindhoven; Zhang, Z.

Optical data of Sm, Tb and Yb doped Ca{sub 2}Si{sub 5}N{sub 8} and Sr{sub 2}Si{sub 5}N{sub 8} phosphors that have been prepared by solid-state synthesis, are presented. Together with luminescence data from literature on Ce{sup 3+} and Eu{sup 2+} doping in the M{sub 2}Si{sub 5}N{sub 8} (M=Ca, Sr, Ba) hosts, energy level schemes were constructed showing the energy of the 4f and 5d levels of all divalent and trivalent lanthanide ions relative to the valence and conduction band. The schemes were of great help in interpreting the optical data of the lanthanide doped phosphors and allow commenting on the valencemore » stability of the ions, as well as the stability against thermal quenching of the Eu{sup 2+}d-f emission. Tb{sup 3+} substitutes on both a high energy and a low energy site in Ca{sub 2}Si{sub 5}N{sub 8}, due to which excitation at 4.77 eV led to emission from both the {sup 5}D{sub 3} and {sup 5}D{sub 4} levels, while excitation at 4.34 eV gave rise to mainly {sup 5}D{sub 4} emission. Doping with Sm resulted in typical Sm{sup 3+}f-f line absorption, as well as an absorption band around 4.1 eV in Ca{sub 2}Si{sub 5}N{sub 8} and 3.6 eV in Sr{sub 2}Si{sub 5}N{sub 8} that could be identified as the Sm{sup 3+} charge transfer band. Yb on the other hand was incorporated in both the divalent and the trivalent state in Ca{sub 2}Si{sub 5}N{sub 8}. - Graphical abstract: Energy level schemes showing the 4f ground states of the trivalent ( Black-Down-Pointing-Small-Triangle ) and divalent ( Black-Up-Pointing-Small-Triangle ) lanthanide ions and lowest energy 5d states of the trivalent ({nabla}) and divalent ({Delta}) ions with respect to the valence and conduction bands of Ca{sub 2}Si{sub 5}N{sub 8} (left) and Sr{sub 2}Si{sub 5}N{sub 8} (right). Highlights: Black-Right-Pointing-Pointer Construction of energy level schemes of all lanthanides within the M{sub 2}Si{sub 5}N{sub 8} hosts. Black-Right-Pointing-Pointer Construction was done by analyzing existing as well as new spectroscopic data. Black-Right-Pointing-Pointer Tb{sup 3+}d-f emission from two different Ca sites in Ca{sub 2}Si{sub 5}N{sub 8} has been observed. Black-Right-Pointing-Pointer Observation of the Sm{sup 3+} charge transfer band in Ca{sub 2}Si{sub 5}N{sub 8} and Sr{sub 2}Si{sub 5}N{sub 8}. Black-Right-Pointing-Pointer Ytterbium has been found in the divalent and trivalent state in Ca{sub 2}Si{sub 5}N{sub 8}.« less

The Sociology of the Gene: Genetics and Education on the Eve of the Biotech Century.

ERIC Educational Resources Information Center

Rifkin, Jeremy

1998-01-01

Researchers in molecular biology are discovering an increasing genetic basis for a wide range of mental diseases, moods, behaviors, and personality traits. Findings are creating the context for a new sociobiology favoring a genetic interpretation of human motivations and drives. Genetic engineering will give some people unprecedented power over…

A synthetic genetic edge detection program.

PubMed

Tabor, Jeffrey J; Salis, Howard M; Simpson, Zachary Booth; Chevalier, Aaron A; Levskaya, Anselm; Marcotte, Edward M; Voigt, Christopher A; Ellington, Andrew D

2009-06-26

Edge detection is a signal processing algorithm common in artificial intelligence and image recognition programs. We have constructed a genetically encoded edge detection algorithm that programs an isogenic community of E. coli to sense an image of light, communicate to identify the light-dark edges, and visually present the result of the computation. The algorithm is implemented using multiple genetic circuits. An engineered light sensor enables cells to distinguish between light and dark regions. In the dark, cells produce a diffusible chemical signal that diffuses into light regions. Genetic logic gates are used so that only cells that sense light and the diffusible signal produce a positive output. A mathematical model constructed from first principles and parameterized with experimental measurements of the component circuits predicts the performance of the complete program. Quantitatively accurate models will facilitate the engineering of more complex biological behaviors and inform bottom-up studies of natural genetic regulatory networks.

Genetic Engineering and Human Mental Ecology: Interlocking Effects and Educational Considerations.

PubMed

Affifi, Ramsey

2017-01-01

This paper describes some likely semiotic consequences of genetic engineering on what Gregory Bateson has called "the mental ecology" (1979) of future humans, consequences that are less often raised in discussions surrounding the safety of GMOs (genetically modified organisms). The effects are as follows: an increased 1) habituation to the presence of GMOs in the environment, 2) normalization of empirically false assumptions grounding genetic reductionism, 3) acceptance that humans are capable and entitled to decide what constitutes an evolutionary improvement for a species, 4) perception that the main source of creativity and problem solving in the biosphere is anthropogenic. Though there are some tensions between them, these effects tend to produce self-validating webs of ideas, actions, and environments, which may reinforce destructive habits of thought. Humans are unlikely to safely develop genetic technologies without confronting these escalating processes directly. Intervening in this mental ecology presents distinct challenges for educators, as will be discussed.

A Synthetic Genetic Edge Detection Program

PubMed Central

Tabor, Jeffrey J.; Salis, Howard; Simpson, Zachary B.; Chevalier, Aaron A.; Levskaya, Anselm; Marcotte, Edward M.; Voigt, Christopher A.; Ellington, Andrew D.

2009-01-01

Summary Edge detection is a signal processing algorithm common in artificial intelligence and image recognition programs. We have constructed a genetically encoded edge detection algorithm that programs an isogenic community of E.coli to sense an image of light, communicate to identify the light-dark edges, and visually present the result of the computation. The algorithm is implemented using multiple genetic circuits. An engineered light sensor enables cells to distinguish between light and dark regions. In the dark, cells produce a diffusible chemical signal that diffuses into light regions. Genetic logic gates are used so that only cells that sense light and the diffusible signal produce a positive output. A mathematical model constructed from first principles and parameterized with experimental measurements of the component circuits predicts the performance of the complete program. Quantitatively accurate models will facilitate the engineering of more complex biological behaviors and inform bottom-up studies of natural genetic regulatory networks. PMID:19563759

Smad8/BMP2-engineered mesenchymal stem cells induce accelerated recovery of the biomechanical properties of the Achilles tendon.

PubMed

Pelled, Gadi; Snedeker, Jess G; Ben-Arav, Ayelet; Rigozzi, Samuela; Zilberman, Yoram; Kimelman-Bleich, Nadav; Gazit, Zulma; Müller, Ralph; Gazit, Dan

2012-12-01

Tendon tissue regeneration is an important goal for orthopedic medicine. We hypothesized that implantation of Smad8/BMP2-engineered MSCs in a full-thickness defect of the Achilles tendon (AT) would induce regeneration of tissue with improved biomechanical properties. A 2 mm defect was created in the distal region of murine ATs. The injured tendons were then sutured together or given implants of genetically engineered MSCs (GE group), non-engineered MSCs (CH3 group), or fibrin gel containing no cells (FG group). Three weeks later the mice were killed, and their healing tendons were excised and processed for histological or biomechanical analysis. A biomechanical analysis showed that tendons that received implants of genetically engineered MSCs had the highest effective stiffness (>70% greater than natural healing, p < 0.001) and elastic modulus. There were no significant differences in either ultimate load or maximum stress among the treatment groups. Histological analysis revealed a tendon-like structure with elongated cells mainly in the GE group. ATs that had been implanted with Smad8/BMP2-engineered stem cells displayed a better material distribution and functional recovery than control groups. While additional study is required to determine long-term effects of GE MSCs on tendon healing, we conclude that genetically engineered MSCs may be a promising therapeutic tool for accelerating short-term functional recovery in the treatment of tendon injuries. Copyright © 2012 Orthopaedic Research Society.

Insertional engineering of chromosomes with Sleeping Beauty transposition: an overview.

PubMed

Grabundzija, Ivana; Izsvák, Zsuzsanna; Ivics, Zoltán

2011-01-01

Novel genetic tools and mutagenesis strategies based on the Sleeping Beauty (SB) transposable element are currently under development with a vision to link primary DNA sequence information to gene functions in vertebrate models. By virtue of its inherent capacity to insert into DNA, the SB transposon can be developed into powerful tools for chromosomal manipulations. Mutagenesis screens based on SB have numerous advantages including high throughput and easy identification of mutated alleles. Forward genetic approaches based on insertional mutagenesis by engineered SB transposons have the advantage of providing insight into genetic networks and pathways based on phenotype. Indeed, the SB transposon has become a highly instrumental tool to induce tumors in experimental animals in a tissue-specific -manner with the aim of uncovering the genetic basis of diverse cancers. Here, we describe a battery of mutagenic cassettes that can be applied in conjunction with SB transposon vectors to mutagenize genes, and highlight versatile experimental strategies for the generation of engineered chromosomes for loss-of-function as well as gain-of-function mutagenesis for functional gene annotation in vertebrate models.

Insights into wild-type and mutant p53 functions provided by genetically engineered mice.

PubMed

Donehower, Lawrence A

2014-06-01

Recent whole-exome sequencing studies of numerous human cancers have now conclusively shown that the TP53 tumor-suppressor gene is the most frequently mutated gene in human cancers. Despite extensive studies of the TP53 gene and its encoded protein (p53), our understanding of how TP53 mutations contribute to cancer initiation and progression remain incomplete. Genetically engineered mice with germline or inducible Trp53 somatic mutations have provided important insights into the mechanisms by which different types of p53 mutation influence cancer development. Trp53 germline mutations that alter specific p53 structural domains or posttranslation modification sites have benefitted our understanding of wild-type p53 functions in a whole organism context. Moreover, genetic approaches to reestablish functional wild-type p53 to p53-deficient tissues and tumors have increased our understanding of the therapeutic potential of restoring functional p53 signaling to cancers. This review outlines many of the key insights provided by the various categories of Trp53 mutant mice that have been generated by multiple genetic engineering approaches. © 2014 WILEY PERIODICALS, INC.

Hairpin plum pox virus coat protein (hpPPV-CP) structure in 'HoneySweet' C5 plum provides PPV resistance when genetically engineered into plum (Prunus domestica) seedlings

USDA-ARS?s Scientific Manuscript database

The genetically engineered plum 'HoneySweet' (aka C5) has proven to be highly resistant to Plum pox virus (PPV) for over 10 years in field trials. The original vector used for transformation to develop 'HoneySweet' carried a single sense sequence of the full length PPV coat protein (ppv-cp) gene, y...

[Genetic engineering of forest woody plants].

PubMed

Mashkina, O S; Butorina, A K

2003-03-01

The present state of genetic engineering (GE) of forest woody plants is considered with special reference to the materials of the International Conference "Wood, Breeding, Biotechnology and Industrial Expectations" held in France in June, 2001. Main tree species subjected to GE are listed, aims of constructing transgenic plants discussed, and methods described. Major achievements in the field are considered along with the problems associated with the employment of GE in the breeding of forest woody plants.

Fate and transport of bacteria injected into aquifers

USGS Publications Warehouse

Harvey, Ronald W.

1993-01-01

Advances in our understanding of the fate and transport of bacteria introduced into aquifers, including the potential use of genetically engineered bacteria for biorestoration, are highlighted by new findings in the following areas: modeling of bacterial attachment during transport through porous media, the long-term survival of a chlorobenzoate-degrading bacterium injected into a contaminated sandy aquifer, and molecular techniques that may be used in tracking genetically engineered bacteria in groundwater environments.

A Genetically Engineered Mouse Model of Sporadic Colorectal Cancer.

PubMed

Betzler, Alexander M; Kochall, Susan; Blickensdörfer, Linda; Garcia, Sebastian A; Thepkaysone, May-Linn; Nanduri, Lahiri K; Muders, Michael H; Weitz, Jürgen; Reissfelder, Christoph; Schölch, Sebastian

2017-07-06

Despite the advantages of easy applicability and cost-effectiveness, colorectal cancer mouse models based on tumor cell injection have severe limitations and do not accurately simulate tumor biology and tumor cell dissemination. Genetically engineered mouse models have been introduced to overcome these limitations; however, such models are technically demanding, especially in large organs such as the colon in which only a single tumor is desired. As a result, an immunocompetent, genetically engineered mouse model of colorectal cancer was developed which develops highly uniform tumors and can be used for tumor biology studies as well as therapeutic trials. Tumor development is initiated by surgical, segmental infection of the distal colon with adeno-cre virus in compound conditionally mutant mice. The tumors can be easily detected and monitored via colonoscopy. We here describe the surgical technique of segmental adeno-cre infection of the colon, the surveillance of the tumor via high-resolution colonoscopy and present the resulting colorectal tumors.

Targeted drug delivery using genetically engineered diatom biosilica.

PubMed

Delalat, Bahman; Sheppard, Vonda C; Rasi Ghaemi, Soraya; Rao, Shasha; Prestidge, Clive A; McPhee, Gordon; Rogers, Mary-Louise; Donoghue, Jacqueline F; Pillay, Vinochani; Johns, Terrance G; Kröger, Nils; Voelcker, Nicolas H

2015-11-10

The ability to selectively kill cancerous cell populations while leaving healthy cells unaffected is a key goal in anticancer therapeutics. The use of nanoporous silica-based materials as drug-delivery vehicles has recently proven successful, yet production of these materials requires costly and toxic chemicals. Here we use diatom microalgae-derived nanoporous biosilica to deliver chemotherapeutic drugs to cancer cells. The diatom Thalassiosira pseudonana is genetically engineered to display an IgG-binding domain of protein G on the biosilica surface, enabling attachment of cell-targeting antibodies. Neuroblastoma and B-lymphoma cells are selectively targeted and killed by biosilica displaying specific antibodies sorbed with drug-loaded nanoparticles. Treatment with the same biosilica leads to tumour growth regression in a subcutaneous mouse xenograft model of neuroblastoma. These data indicate that genetically engineered biosilica frustules may be used as versatile 'backpacks' for the targeted delivery of poorly water-soluble anticancer drugs to tumour sites.

Genetic engineering of woody plants: current and future targets in a stressful environment.

PubMed

Osakabe, Yuriko; Kajita, Shinya; Osakabe, Keishi

2011-06-01

Abiotic stress is a major factor in limiting plant growth and productivity. Environmental degradation, such as drought and salinity stresses, will become more severe and widespread in the world. To overcome severe environmental stress, plant biotechnologies, such as genetic engineering in woody plants, need to be implemented. The adaptation of plants to environmental stress is controlled by cascades of molecular networks including cross-talk with other stress signaling mechanisms. The present review focuses on recent studies concerning genetic engineering in woody plants for the improvement of the abiotic stress responses. Furthermore, it highlights the recent advances in the understanding of molecular responses to stress. The review also summarizes the basis of a molecular mechanism for cell wall biosynthesis and the plant hormone responses to regulate tree growth and biomass in woody plants. This would facilitate better understanding of the control programs of biomass production under stressful conditions. Copyright © Physiologia Plantarum 2011.

Impact of accelerated plant growth on seed variety development

NASA Astrophysics Data System (ADS)

Christophersen, Eric

1998-01-01

The commercial lives of agricultural seed products have steadily declined in recent years. The introduction of genetically engineered crop seeds in 1966 has accentuated that trend. Widespread grower demand for genetically engineered seed requires competitive response by industry followers in order to avert market share losses to the industry leaders. Limitations on plant transformation technology, regulatory requirements and patent impediments require companies to rapidly convert transformed lines into elite commercial products. Massive multigenerational backcrossing efforts are required to distribute genetically engineered traits into a broad product mix. Significant incidents of expression failures, or ``gene silencing,'' have occurred unexpectedly, requiring product substitution strategies. First-to-market strategies, competitive response, broad germplasm conversion and rescue of product failures all share the element of urgency. Technologies which reliably accelerate product development rates can expect favorable reception by commercial seed developers. A growth chamber which dramatically accelerates the rate of plant growth is described.

Application of genetically engineered microbial whole-cell biosensors for combined chemosensing.

PubMed

He, Wei; Yuan, Sheng; Zhong, Wen-Hui; Siddikee, Md Ashaduzzaman; Dai, Chuan-Chao

2016-02-01

The progress of genetically engineered microbial whole-cell biosensors for chemosensing and monitoring has been developed in the last 20 years. Those biosensors respond to target chemicals and produce output signals, which offer a simple and alternative way of assessment approaches. As actual pollution caused by human activities usually contains a combination of different chemical substances, how to employ those biosensors to accurately detect real contaminant samples and evaluate biological effects of the combined chemicals has become a realistic object of environmental researches. In this review, we outlined different types of the recent method of genetically engineered microbial whole-cell biosensors for combined chemical evaluation, epitomized their detection performance, threshold, specificity, and application progress that have been achieved up to now. We also discussed the applicability and limitations of this biosensor technology and analyzed the optimum conditions for their environmental assessment in a combined way.

Molecular Cloning Designer Simulator (MCDS): All-in-one molecular cloning and genetic engineering design, simulation and management software for complex synthetic biology and metabolic engineering projects.

PubMed

Shi, Zhenyu; Vickers, Claudia E

2016-12-01

Molecular Cloning Designer Simulator (MCDS) is a powerful new all-in-one cloning and genetic engineering design, simulation and management software platform developed for complex synthetic biology and metabolic engineering projects. In addition to standard functions, it has a number of features that are either unique, or are not found in combination in any one software package: (1) it has a novel interactive flow-chart user interface for complex multi-step processes, allowing an integrated overview of the whole project; (2) it can perform a user-defined workflow of cloning steps in a single execution of the software; (3) it can handle multiple types of genetic recombineering, a technique that is rapidly replacing classical cloning for many applications; (4) it includes experimental information to conveniently guide wet lab work; and (5) it can store results and comments to allow the tracking and management of the whole project in one platform. MCDS is freely available from https://mcds.codeplex.com.

Not all GMOs are crop plants: non-plant GMO applications in agriculture.

PubMed

Hokanson, K E; Dawson, W O; Handler, A M; Schetelig, M F; St Leger, R J

2014-12-01

Since tools of modern biotechnology have become available, the most commonly applied and often discussed genetically modified organisms are genetically modified crop plants, although genetic engineering is also being used successfully in organisms other than plants, including bacteria, fungi, insects, and viruses. Many of these organisms, as with crop plants, are being engineered for applications in agriculture, to control plant insect pests or diseases. This paper reviews the genetically modified non-plant organisms that have been the subject of permit approvals for environmental release by the United States Department of Agriculture/Animal and Plant Health Inspection Service since the US began regulating genetically modified organisms. This is an indication of the breadth and progress of research in the area of non-plant genetically modified organisms. This review includes three examples of promising research on non-plant genetically modified organisms for application in agriculture: (1) insects for insect pest control using improved vector systems; (2) fungal pathogens of insects to control insect pests; and (3) virus for use as transient-expression vectors for disease control in plants.

Genetic design automation: engineering fantasy or scientific renewal?

PubMed

Lux, Matthew W; Bramlett, Brian W; Ball, David A; Peccoud, Jean

2012-02-01

The aim of synthetic biology is to make genetic systems more amenable to engineering, which has naturally led to the development of computer-aided design (CAD) tools. Experimentalists still primarily rely on project-specific ad hoc workflows instead of domain-specific tools, which suggests that CAD tools are lagging behind the front line of the field. Here, we discuss the scientific hurdles that have limited the productivity gains anticipated from existing tools. We argue that the real value of efforts to develop CAD tools is the formalization of genetic design rules that determine the complex relationships between genotype and phenotype. Copyright © 2011 Elsevier Ltd. All rights reserved.

Commodifying animals: ethical issues in genetic engineering of animals.

PubMed

Almond, B

2000-03-01

The genetic modification of living beings raises special ethical concerns which go beyond general discussion of animal rights or welfare. Although the goals may be similar, biotechnology has accelerated the process of modification of types traditionally carried out by cross-breeding. These changes are discussed in relation to two areas: biomedicine, and animal husbandry. Alternative ethical approaches are reviewed, and it is argued that the teleological thesis underlying virtue ethics has special relevance here. The case for and the case against genetic engineering and patenting of life-forms are examined, and conclusions are drawn which favour regulation, caution and respect for animals and animal species.

Linear scaffolds for multivalent targeting of melanocortin receptors.

PubMed

Dehigaspitiya, Dilani Chathurika; Anglin, Bobbi L; Smith, Kara R; Weber, Craig S; Lynch, Ronald M; Mash, Eugene A

2015-12-21

Molecules bearing one, two, three, or four copies of the tetrapeptide His-dPhe-Arg-Trp were attached to scaffolds based on ethylene glycol, glycerol, and d-mannitol by means of the copper-assisted azide-alkyne cyclization. The abilities of these compounds to block binding of a probe at the melanocortin 4 receptor were evaluated using a competitive binding assay. All of the multivalent molecules studied exhibited 30- to 40-fold higher apparent affinites when compared to a monovalent control. These results are consistent with divalent binding to receptor dimers. No evidence for tri- or tetravalent binding was obtained. Differences in the interligand spacing required for divalent binding, as opposed to tri- or tetravalent binding, may be responsible for these results.

Structures and interactions among globular proteins above the isoelectric point in the presence of divalent ions: A small angle neutron scattering and dynamic light scattering study

NASA Astrophysics Data System (ADS)

Kundu, Sarathi; Pandit, Subhankar; Abbas, Sohrab; Aswal, V. K.; Kohlbrecher, J.

2018-02-01

Small angle neutron scattering study reveals that at pD ≈ 7.0, above the isoelectric point of the globular protein Bovine Serum Albumin (BSA), in the presence of different divalent ions (Mg2+, Ca2+, Sr2+ and Ba2+), the short-range attractive interaction remains nearly constant and the intermediate-range repulsive interaction decreases with increasing salt concentration up to a certain concentration value but after that remains unchanged. However, for the monovalent ion (Na+), repulsive interaction decreases gradually up to 1 M salt concentration. Dynamic light scattering study shows that for all ions, diffusion coefficient of BSA decreases with increasing salt concentration and then nearly saturates.

Biogeochemical evidence for subsurface hydrocarbon occurrence, Recluse oil field, Wyoming; preliminary results

USGS Publications Warehouse

Dalziel, Mary C.; Donovan, Terrence J.

1980-01-01

Anomalously high manganese-to-iron ratios occurring in pine needles and sage leaves over the Recluse oil field, Wyoming, suggest effects of petroleum microseepage on the plants. This conclusion is supported by iron and manganese concentrations in soils and carbon and oxygen isotope ratios in rock samples. Seeping hydrocarbons provided reducing conditions sufficient to enable divalent iron and manganese to be organically complexed or adsorbed on solids in the soils. These bound or adsorped elements in the divalent state are essential to plants, and the plants readily assimilate them. The magnitude of the plant anomalies, combined with the supportive isotopic and chemical evidence confirming petroleum leakage, makes a strong case for the use of plants as a biogeochemical prospecting tool.

One- and two-dimensional divalent copper coordination polymers based on kinked organodiimine and long flexible aliphatic dicarboxylate ligands

NASA Astrophysics Data System (ADS)

Mallika Krishnan, Subhashree; Supkowski, Ronald M.; LaDuca, Robert L.

2008-11-01

Hydrothermal synthesis under acidic conditions has afforded a pair of divalent copper coordination polymers containing the kinked dipodal tethering organodiimine 4,4'-dipyridylamine (dpa) and flexible long-chain aliphatic dicarboxylate ligands. The new materials were characterized by single crystal X-ray structure determination, infrared spectroscopy, and thermogravimetric analysis. [CuCl(suberate) 0.5(dpa)] ( 1) manifests 1-D ladder-like motifs aggregated into 3-D through hydrogen bonding and copper-mediated supramolecular interactions. Extension of the aliphatic chain within the dicarboxylate ligand by one methylene unit resulted in {[Cu(azelate)(dpa)(H 2O)] · 3H 2O} ( 2), a (4,4) rhomboid grid 2-D coordination polymer encapsulating acyclic water molecule trimers.

Reduced chromium in olivine grains from lunar basalt 15555 - X-ray Absorption Near Edge Structure (XANES)

NASA Technical Reports Server (NTRS)

Sutton, S. R.; Jones, K. W.; Gordon, B.; Rivers, M. L.; Bajt, S.; Smith, J. V.

1993-01-01

The oxidation state of Cr in 200-micron regions within individual lunar olivine and pyroxene grains from lunar basalt 15555 was inferred using X-ray Absorption Near Edge Structure (XANES). Reference materials had previously been studied by optical absorption spectroscopy and included Cr-bearing borosilicate glasses synthesized under controlled oxygen fugacity and Cr-doped olivines. The energy dependence of XANES spectral features defined by these reference materials indicated that Cr is predominantly divalent in the lunar olivine and trivalent in the pyroxene. These results, coupled with the apparent f(02)-independence of partitioning coefficients for Cr into olivine, imply that the source magma was dominated by divalent Cr at the time of olivine crystallization.

Ultrafast intersystem crossings in Fe-Co Prussian blue analogues

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Veenendaal, Michel

Ultrafast spincrossover is studied in Fe-Co Prussian blue analogues using a dissipative quantum-mechanical model of a cobalt ion coupled to a breathing mode. All electronic interactions are treated on an equal footing. It is theoretically demonstrated that the divalent cobalt ion reaches 90% of the S = 3/2 value within 20 fs after photoexciting a low-spin Co 3+ ion by an iron-to-cobalt charge transfer. The doublet-to-quartet spin crossover is significantly faster than the oscillation period of the breathing mode. The system relaxes to the lowest manifold of divalent cobalt ( 4T 1) in 150-200 fs. In conclusion, strong oscillations inmore » spin-orbit coupling and the involvement of higher-lying quartets are found.« less

Ultrafast intersystem crossings in Fe-Co Prussian blue analogues

DOE PAGES

van Veenendaal, Michel

2017-07-27

Ultrafast spincrossover is studied in Fe-Co Prussian blue analogues using a dissipative quantum-mechanical model of a cobalt ion coupled to a breathing mode. All electronic interactions are treated on an equal footing. It is theoretically demonstrated that the divalent cobalt ion reaches 90% of the S = 3/2 value within 20 fs after photoexciting a low-spin Co 3+ ion by an iron-to-cobalt charge transfer. The doublet-to-quartet spin crossover is significantly faster than the oscillation period of the breathing mode. The system relaxes to the lowest manifold of divalent cobalt ( 4T 1) in 150-200 fs. In conclusion, strong oscillations inmore » spin-orbit coupling and the involvement of higher-lying quartets are found.« less

Effect of Divalent Cations on the Structure of the Antibiotic Daptomycin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, Steven W.; Jung, David; Calhoun, Jennifer R.

Abstract Daptomycin, a cyclic anionic lipopeptide antibiotic, whose three-dimensional structure was recently solved using solution state NMR (Ball et al. 2004; Jung et al. 2004; Rotondi and Gierasch 2005), requires calcium for function. To date, the exact nature of the interaction between divalent cations, such as Ca2+ or Mg2+, has not been fully characterized. It has, however, been suggested that addition of Ca2+ to daptomycin in a 1:1 molar ratio induces aggregation. Moreover, it has been suggested that certain residues, e.g. Asp3 and Asp7, which are essential for activity (Grunewald et al. 2004; Kopp et al. 2006), may also bemore » important for Ca2+ binding (Jung et al. 2004).« less

Divalent europium doped CaF 2 and BaF 2 nanocrystals from ionic liquids

DOE PAGES

Anghel, Sergiu; Golbert, Sebastian; Meijerink, Andries; ...

2016-10-11

A new, facile and quick synthesis method for Eu 2+ doped the alkaline earth fluorides was developed using ionic liquids as solvent, precursor and capping agent. Reductive atmosphere and very high temperatures were avoided, while still attaining the desired structure, small particle sizes and divalent oxidation state of the lanthanide. Here, this opens the door for the development of new Ln 2+ doped nanomaterials. Here, the successful Eu 2+ incorporation was proven by optical spectroscopic measurements which showed the spin and parity allowed f-d transitions of Eu 2+ in CaF 2:Eu 2+/BaF 2:Eu 2+. 4f 7-4f 7 transitions could bemore » observed at low temperatures (7 K).« less

Interactions of chlorphenesin and divalent metal ions with phosphodiesterase.

PubMed

Edelson, J; McMullen, J P

1976-09-01

Chlorphenesin inhibition of the hydrolysis of cyclic AMP by guinea-pig lung phosphodiesterase was reversed by the addition of exogenous magnesium ions. Chlorphenesin and theophylline inhibition of this enzyme was shown to be noncompetitive when the substrate concentration was low. Kinetic studies of the inhibition of beef heart phosphodiesterase by chlorphenesin and theophylline indicated that the substrate concentration was a factor in determining whether inhibition was competitive or noncompetitive. Calcium, cobalt and copper ions were inhibitory to guinea-pig lung phosphodiesterase. The inhibition due to chlorphenesin was partially reversed by low (40 mM or less) concentrations of barium ions; high concentrations of barium ions, or manganese ions, were inhibitory. The concentration of the divalent cation did not affect the type of inhibition that was observed.

Production of amino acids - Genetic and metabolic engineering approaches.

PubMed

Lee, Jin-Ho; Wendisch, Volker F

2017-12-01

The biotechnological production of amino acids occurs at the million-ton scale and annually about 6milliontons of l-glutamate and l-lysine are produced by Escherichia coli and Corynebacterium glutamicum strains. l-glutamate and l-lysine production from starch hydrolysates and molasses is very efficient and access to alternative carbon sources and new products has been enabled by metabolic engineering. This review focusses on genetic and metabolic engineering of amino acid producing strains. In particular, rational approaches involving modulation of transcriptional regulators, regulons, and attenuators will be discussed. To address current limitations of metabolic engineering, this article gives insights on recent systems metabolic engineering approaches based on functional tools and method such as genome reduction, amino acid sensors based on transcriptional regulators and riboswitches, CRISPR interference, small regulatory RNAs, DNA scaffolding, and optogenetic control, and discusses future prospects. Copyright © 2017 Elsevier Ltd. All rights reserved.

Genetic Modification in Dedicated Bioenergy Crops and Strategies for Gene Confinement

USDA-ARS?s Scientific Manuscript database

Genetic modification of dedicated bioenergy crops is in its infancy; however, there are numerous advantages to the use of these tools to improve crops used for biofuels. Potential improved traits through genetic engineering (GE) include herbicide resistance, pest, drought, cold and salt tolerance, l...

Not all GMOs are crop plants: non-plant GMO applications in agriculture

USDA-ARS?s Scientific Manuscript database

In the time since the tools of modern biotechnology have become available, the most commonly applied and often discussed genetically modified organisms are genetically modified crop plants, although genetic engineering is also being used successfully in organisms other than plants, including bacteri...

Mechanisms, applications, and perspectives of antiviral RNA silencing in plants

PubMed Central

Garcia-Ruiz, Hernan; Ruiz, Mayra Teresa Garcia; Peralta, Sergio Manuel Gabriel; Gabriel, Cristina Betzabeth Miravel; El-Mounadi, Kautar

2017-01-01

Viral diseases of plants cause important economic losses due to reduction in crop quality and quantity to the point of threatening food security in some countries. Given the reduced availability of natural sources, genetic resistance to viruses has been successfully engineered for some plant-virus combinations. A sound understanding of the basic mechanisms governing plant-virus interactions, including antiviral RNA silencing, is the foundation to design better management strategies and biotechnological approaches to engineer and implement antiviral resistance in plants. In this review, we present current molecular models to explain antiviral RNA silencing and its application in basic plant research, biotechnology and genetic engineering. PMID:28890589

Overview of genetically engineered mouse models of colorectal carcinoma to enable translational biology and drug development.

PubMed

Roper, Jatin; Martin, Eric S; Hung, Kenneth E

2014-06-16

Preclinical models for colorectal cancer (CRC) are critical for translational biology and drug development studies to characterize and treat this condition. Mouse models of human cancer are particularly popular because of their relatively low cost, short life span, and ease of use. Genetically engineered mouse models (GEMMs) of CRC are engineered from germline or somatic modification of critical tumor suppressor genes and/or oncogenes that drive mutations in human disease. Detailed in this overview are the salient features of several useful colorectal cancer GEMMs and their value as tools for translational biology and preclinical drug development. Copyright © 2014 John Wiley & Sons, Inc.

Department of Defense In-House RDT&E Activities

DTIC Science & Technology

1980-10-30

FOPCeS;C TO ,DEVELOP PRFVFNTIVE & THERAPEUTIC METHO"DS TO PROTECT PERSONNFL FROnM SUCH rnRCFS, .,,CURRENT IMPOPTANT PROGRAMS LONG-TERM EcEFCTS OF...Plant Quarantine & Pest 819 Sanitary Engineering Control 830 Mechanical Engineering 437 Horticulture 840 Nuclear Engineering 440 Genetics 850

Precision genome engineering in lactic acid bacteria

PubMed Central

2014-01-01

Innovative new genome engineering technologies for manipulating chromosomes have appeared in the last decade. One of these technologies, recombination mediated genetic engineering (recombineering) allows for precision DNA engineering of chromosomes and plasmids in Escherichia coli. Single-stranded DNA recombineering (SSDR) allows for the generation of subtle mutations without the need for selection and without leaving behind any foreign DNA. In this review we discuss the application of SSDR technology in lactic acid bacteria, with an emphasis on key factors that were critical to move this technology from E. coli into Lactobacillus reuteri and Lactococcus lactis. We also provide a blueprint for how to proceed if one is attempting to establish SSDR technology in a lactic acid bacterium. The emergence of CRISPR-Cas technology in genome engineering and its potential application to enhancing SSDR in lactic acid bacteria is discussed. The ability to perform precision genome engineering in medically and industrially important lactic acid bacteria will allow for the genetic improvement of strains without compromising safety. PMID:25185700

Genetically engineered plants with increased vegetative oil content

DOEpatents

Benning, Christoph

2017-05-23

The invention relates to genetically modified agricultural plants with increased oil content in vegetative tissues, as well as to expression systems, plant cells, seeds and vegetative tissues related thereto.

40 CFR 158.2110 - Microbial pesticides data requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

...: genetic engineering techniques used; the identity of the inserted or deleted gene segment (base sequence... evaluate genetic stability and exchange; and selected Tier II environmental expression and toxicology tests. ...

40 CFR 158.2110 - Microbial pesticides data requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

...: genetic engineering techniques used; the identity of the inserted or deleted gene segment (base sequence... evaluate genetic stability and exchange; and selected Tier II environmental expression and toxicology tests. ...

40 CFR 158.2110 - Microbial pesticides data requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

...: genetic engineering techniques used; the identity of the inserted or deleted gene segment (base sequence... evaluate genetic stability and exchange; and selected Tier II environmental expression and toxicology tests. ...

40 CFR 158.2110 - Microbial pesticides data requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

...: genetic engineering techniques used; the identity of the inserted or deleted gene segment (base sequence... evaluate genetic stability and exchange; and selected Tier II environmental expression and toxicology tests. ...

Redirecting adenovirus tropism by genetic, chemical, and mechanical modification of the adenovirus surface for cancer gene therapy.

PubMed

Yoon, A-Rum; Hong, Jinwoo; Kim, Sung Wan; Yun, Chae-Ok

2016-06-01

Despite remarkable advancements, clinical evaluations of adenovirus (Ad)-mediated cancer gene therapies have highlighted the need for improved delivery and targeting. Genetic modification of Ad capsid proteins has been extensively attempted. Although genetic modification enhances the therapeutic potential of Ad, it is difficult to successfully incorporate extraneous moieties into the capsid and the engineering process is laborious. Recently, chemical modification of the Ad surface with nanomaterials and targeting moieties has been found to enhance Ad internalization into the target by both passive and active mechanisms. Alternatively, external stimulus-mediated targeting can result in selective accumulation of Ad in the tumor and prevent dissemination of Ad into surrounding nontarget tissues. In the present review, we discuss various genetic, chemical, and mechanical engineering strategies for overcoming the challenges that hinder the therapeutic efficacy of Ad-based approaches. Surface modification of Ad by genetic, chemical, or mechanical engineering strategies enables Ad to overcome the shortcomings of conventional Ad and enhances delivery efficiency through distinct and unique mechanisms that unmodified Ad cannot mimic. However, although the therapeutic potential of Ad-mediated gene therapy has been enhanced by various surface modification strategies, each strategy still possesses innate limitations that must be addressed, requiring innovative ideas and designs.

The regulation of agricultural biotechnology: science shows a better way.

PubMed

Miller, Henry I

2010-11-30

National and international regulation of recombinant DNA-modified, or 'genetically engineered' (also referred to as 'genetically modified' or GM), organisms is unscientific and illogical, a lamentable illustration of the maxim that bad science makes bad law. Instead of regulatory scrutiny that is proportional to risk, the degree of oversight is actually inversely proportional to risk. The current approach to regulation, which captures for case-by-case review organisms to be field tested or commercialized according to the techniques used to construct them rather than their properties, flies in the face of scientific consensus. This approach has been costly in terms of economic losses and human suffering. The poorest of the poor have suffered the most because of hugely inflated development costs of genetically engineered plants and food. A model for regulation of field trials known as the 'Stanford Model' is designed to assess risks of new agricultural introductions - whether or not the organisms are genetically engineered, and independent of the genetic modification techniques employed. It offers a scientific, rational, risk-based basis for field trial regulations. Using this sort of model for regulatory review would not only better protect human health and the environment, but would also permit more expeditious development and more widespread use of new plants and seeds. Copyright © 2010 Elsevier B.V. All rights reserved.

Current and future delivery systems for engineered nucleases: ZFN, TALEN and RGEN.

PubMed

Ul Ain, Qurrat; Chung, Jee Young; Kim, Yong-Hee

2015-05-10

Gene therapy by engineered nucleases is a genetic intervention being investigated for curing the hereditary disorders by targeting selected genes with specific nucleotides for establishment, suppression, abolishment of a function or correction of mutation. Here, we review the fast developing technology of targeted genome engineering using site specific programmable nucleases zinc finger nucleases (ZFNs), transcription activator like nucleases (TALENs) and cluster regulatory interspaced short palindromic repeat/CRISPR associated proteins (CRISPR/Cas) based RNA-guided DNA endonucleases (RGENs) and their different characteristics including pros and cons of genome modifications by these nucleases. We have further discussed different types of delivery methods to induce gene editing, novel development in genetic engineering other than nucleases and future prospects. Copyright © 2014 Elsevier B.V. All rights reserved.

Engineering microbial hosts for production of bacterial natural products.

PubMed

Zhang, Mingzi M; Wang, Yajie; Ang, Ee Lui; Zhao, Huimin

2016-08-27

Covering up to end 2015Microbial fermentation provides an attractive alternative to chemical synthesis for the production of structurally complex natural products. In most cases, however, production titers are low and need to be improved for compound characterization and/or commercial production. Owing to advances in functional genomics and genetic engineering technologies, microbial hosts can be engineered to overproduce a desired natural product, greatly accelerating the traditionally time-consuming strain improvement process. This review covers recent developments and challenges in the engineering of native and heterologous microbial hosts for the production of bacterial natural products, focusing on the genetic tools and strategies for strain improvement. Special emphasis is placed on bioactive secondary metabolites from actinomycetes. The considerations for the choice of host systems will also be discussed in this review.

Plant genetics, sustainable agriculture and global food security.

PubMed

Ronald, Pamela

2011-05-01

The United States and the world face serious societal challenges in the areas of food, environment, energy, and health. Historically, advances in plant genetics have provided new knowledge and technologies needed to address these challenges. Plant genetics remains a key component of global food security, peace, and prosperity for the foreseeable future. Millions of lives depend upon the extent to which crop genetic improvement can keep pace with the growing global population, changing climate, and shrinking environmental resources. While there is still much to be learned about the biology of plant-environment interactions, the fundamental technologies of plant genetic improvement, including crop genetic engineering, are in place, and are expected to play crucial roles in meeting the chronic demands of global food security. However, genetically improved seed is only part of the solution. Such seed must be integrated into ecologically based farming systems and evaluated in light of their environmental, economic, and social impacts-the three pillars of sustainable agriculture. In this review, I describe some lessons learned, over the last decade, of how genetically engineered crops have been integrated into agricultural practices around the world and discuss their current and future contribution to sustainable agricultural systems.