Journal articles: 'Gröna'

1

Backa, Andreas. "Den gröna drömmen." Budkavlen 97 (November 30, 2018): 111–37. http://dx.doi.org/10.37447/bk.90629.

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Harder, Ingegerd. "Boganmeldelse: Sjuhköterskor: Med gröna fingrar for vårdSjuhköterskor: Med gröna fingrar for vårdSegestenKerstin, Bäck-PettersonSiv & JensenKirsten Pryds. Göteborn, K & K Segesten Förlag, 1993." Nordic Journal of Nursing Research 14, no. 1 (March 1994): 29–30. http://dx.doi.org/10.1177/010740839401400107.

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3

Hallmundsson, Hallberg, and Sigurlaugur Elíasson. "Græna skyggnishúfan." World Literature Today 74, no. 4 (2000): 866. http://dx.doi.org/10.2307/40156233.

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4

Tomić, Zoran. "Administrative law: Embryo of the new conception." Anali Pravnog fakulteta u Beogradu 68, no. 3 (2020): 36–52. http://dx.doi.org/10.5937/analipfb2003038t.

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5

Taraba, Anne-Sophie, and Eva Mattsson. "Groucho i grönt." World Literature Today 62, no. 4 (1988): 674. http://dx.doi.org/10.2307/40144650.

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6

Vedung, Evert. "Grönt för miljöpartiet." Politica 20, no. 4 (January 1, 1988): 432. http://dx.doi.org/10.7146/politica.v20i4.69035.

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7

Osmond, Barry. "Preface: Why grana?" Functional Plant Biology 26, no. 7 (1999): I. http://dx.doi.org/10.1071/ppv26n7_pr.

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The importance of the functional flexibility of the light-harvesting complexes of photo-system II (LHCII) in accommodating the fluctuation in the balance between light input and metabolic capacity in plants is emphasised. This flexibility is provided for by a relatively complex assembly of protein subunits, the interactions between them being controlled by protonation, xanthophyll de-epoxidation and phosphorylation. It is suggested that the 3-dimensional order imposed upon this assembly of proteins by the grana is a vital aspect of the modulation of LHCII function. Grana establish the LHCII conformation needed for efficient light harvesting and help prevent the dense array of proteins from collapsing into a highly dissipative state. The grana then allow a controlled development of non-photochemical quenching under the driving force of violaxanthin de-epoxidation and protonation. In plants grown under different irradiances the different grana content and xanthophyll cycle pool size together allow maximum quantum yield in limiting light and an appropriate level of non-photochemical quenching in excess light.

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8

MOIO, LUIGI, and FRANCESCO ADDEO. "Grana Padano cheese aroma." Journal of Dairy Research 65, no. 2 (May 1998): 317–33. http://dx.doi.org/10.1017/s0022029997002768.

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The volatile concentrate obtained from Grana Padano cheese by vacuum distillation was fractionated by continuous liquid–liquid extraction into neutral and acid fractions. Both were analysed by high resolution gas chromatography (HRGC), HRGC–mass spectrometry, and HRGC–olfactometry. A total of 67 components were identified in the neutral extract (22 esters, 13 alcohols, 12 ketones, 6 aldehydes, 5 nitrogen-containing compounds, 3 lactones and 6 miscellaneous compounds) and 16 in the acid extract. Esters were the predominant constituents of the neutral fraction, whose major components were ethyl butanoate and ethyl hexanoate. HRGC–olfactometry of the neutral compounds demonstrated that 23 were odour-active: ethyl butanoate, 2-heptanol, 3-methylthiopropanal, 1-octen-3-ol, ethyl hexanoate and nonanal being the most potent odorants. n-Butanoic and n-hexanoic acids were the main volatile free fatty acids identified in the acid extract as having an important odour with a high olfactometric index. The backbone of Grana Padano cheese aroma seemed to consist of these acids and 14 potent neutral odorants imparting fruity, green, nutty and coconut notes. The concentration of volatile components responsible for the fruity and green notes was inversely proportional to the length of ripening, whereas the concentration of volatile agents with spicy, nutty and earthy notes tended to increase during maturation. In a comparison of the olfactometric profile, the Grana Padano cheese aroma was found to be more complex than an imitation Grana Padano cheese produced with similar technology but outside the area of the genuine cheese. Some of the main metabolic pathways for the biosynthesis of cheese aroma are reviewed briefly to indicate the possible origin of the compounds identified.

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9

Collins, Scott P., William Rostain, Chunyu Liao, and Chase L. Beisel. "Sequence-independent RNA sensing and DNA targeting by a split domain CRISPR–Cas12a gRNA switch." Nucleic Acids Research 49, no. 5 (February 22, 2021): 2985–99. http://dx.doi.org/10.1093/nar/gkab100.

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Abstract CRISPR technologies increasingly require spatiotemporal and dosage control of nuclease activity. One promising strategy involves linking nuclease activity to a cell's transcriptional state by engineering guide RNAs (gRNAs) to function only after complexing with a ‘trigger’ RNA. However, standard gRNA switch designs do not allow independent selection of trigger and guide sequences, limiting gRNA switch application. Here, we demonstrate the modular design of Cas12a gRNA switches that decouples selection of these sequences. The 5′ end of the Cas12a gRNA is fused to two distinct and non-overlapping domains: one base pairs with the gRNA repeat, blocking formation of a hairpin required for Cas12a recognition; the other hybridizes to the RNA trigger, stimulating refolding of the gRNA repeat and subsequent gRNA-dependent Cas12a activity. Using a cell-free transcription-translation system and Escherichia coli, we show that designed gRNA switches can respond to different triggers and target different DNA sequences. Modulating the length and composition of the sensory domain altered gRNA switch performance. Finally, gRNA switches could be designed to sense endogenous RNAs expressed only under specific growth conditions, rendering Cas12a targeting activity dependent on cellular metabolism and stress. Our design framework thus further enables tethering of CRISPR activities to cellular states.

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10

Habib, Pardes, Ann-Sophie Stamm, Joerg B. Schulz, Arno Reich, Alexander Slowik, Sandro Capellmann, Michael Huber, and Thomas Wilhelm. "EPO and TMBIM3/GRINA Promote the Activation of the Adaptive Arm and Counteract the Terminal Arm of the Unfolded Protein Response after Murine Transient Cerebral Ischemia." International Journal of Molecular Sciences 20, no. 21 (October 31, 2019): 5421. http://dx.doi.org/10.3390/ijms20215421.

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Ischemic stroke is known to cause the accumulation of misfolded proteins and loss of calcium homeostasis leading to impairment of endoplasmic reticulum (ER) function. The unfolded protein response (UPR) is an ER-located and cytoprotective pathway that aims to resolve ER stress. Transmembrane BAX inhibitor-1 motif-containing (TMBIM) protein family member TMBIM3/GRINA is highly expressed in the brain and mostly located at the ER membrane suppressing ER calcium release by inositol-1,4,5-trisphosphate receptors. GRINA confers neuroprotection and is regulated by erythropoietin (EPO) after murine cerebral ischemia. However, the role of GRINA and the impact of EPO treatment on the post-ischemic UPR have not been elucidated yet. We subjected GRINA-deficient (Grina−/−) and wildtype mice to transient (30 min) middle cerebral artery occlusion (tMCAo) followed by 6 h or 72 h of reperfusion. We administered EPO or saline 0, 24 and 48 h after tMCAo/sham surgery. Oxygen–glucose deprivation (OGD) and pharmacological stimulation of the UPR using Tunicamycin and Thapsigargin were carried out in primary murine cortical mixed cell cultures. Treatment with the PERK-inhibitor GSK-2606414, IRE1a-RNase-inhibitor STF-083010 and EPO was performed 1 h prior to either 1 h, 2 h or 3 h of OGD. We found earlier and larger infarct demarcations in Grina−/− mice compared to wildtype mice, which was accompanied by a worse neurological outcome and an abolishment of EPO-mediated neuroprotection after ischemic stroke. In addition, GRINA-deficiency increased apoptosis and the activation of the corresponding PERK arm of the UPR after stroke. EPO enhanced the post-ischemic activation of pro-survival IRE1a and counteracted the pro-apoptotic PERK branch of the UPR. Both EPO and the PERK-inhibitor GSK-2606414 reduced cell death and regulated Grina mRNA levels after OGD. In conclusion, GRINA plays a crucial role in post-ischemic UPR and the use of both GSK-2606414 and EPO might lead to neuroprotection.

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11

Kvam, Kela, and Annette Mester. "Katalog över ‘Gröna Säcken’. Strindbergs Efter-Lämnade Papper I Kungl. Biblioteket, SG NM 1–9. (Catalogue of the ‘Green Bag’: Strind-berg's Posthumous Works at the Royal Library, Sg NM 1–9). By Barbro Ståhle Sjönell. Acta Bibliothecæ Regiæ Stockholmiensis LII. The Royal Library, Stockholm1991. 372 pp." Theatre Research International 18, S1 (March 1993): 82–83. http://dx.doi.org/10.1017/s0307883300021192.

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12

Chameettachal, Akhil, Valérie Vivet-Boudou, Fathima Nuzra Nagoor Pitchai, Vineeta N. Pillai, Lizna Mohamed Ali, Anjana Krishnan, Serena Bernacchi, Farah Mustafa, Roland Marquet, and Tahir A. Rizvi. "A purine loop and the primer binding site are critical for the selective encapsidation of mouse mammary tumor virus genomic RNA by Pr77Gag." Nucleic Acids Research 49, no. 8 (April 9, 2021): 4668–88. http://dx.doi.org/10.1093/nar/gkab223.

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Abstract Retroviral RNA genome (gRNA) harbors cis-acting sequences that facilitate its specific packaging from a pool of other viral and cellular RNAs by binding with high-affinity to the viral Gag protein during virus assembly. However, the molecular intricacies involved during selective gRNA packaging are poorly understood. Binding and footprinting assays on mouse mammary tumor virus (MMTV) gRNA with purified Pr77Gag along with in cell gRNA packaging study identified two Pr77Gag binding sites constituting critical, non-redundant packaging signals. These included: a purine loop in a bifurcated stem-loop containing the gRNA dimerization initiation site, and the primer binding site (PBS). Despite these sites being present on both unspliced and spliced RNAs, Pr77Gag specifically bound to unspliced RNA, since only that could adopt the native bifurcated stem–loop structure containing looped purines. These results map minimum structural elements required to initiate MMTV gRNA packaging, distinguishing features that are conserved amongst divergent retroviruses from those perhaps unique to MMTV. Unlike purine-rich motifs frequently associated with packaging signals, direct involvement of PBS in gRNA packaging has not been documented in retroviruses. These results enhance our understanding of retroviral gRNA packaging/assembly, making it not only a target for novel therapeutic interventions, but also development of safer gene therapy vectors.

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13

Xu, Jianyong, Wenlei Li, MD Munnaf Hossen, Yuning Jia, Lingyun Li, and Zhong Huang. "Optimized Plasmid Construction Strategy for Cas9." Cellular Physiology and Biochemistry 48, no. 1 (2018): 131–37. http://dx.doi.org/10.1159/000491669.

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Background/Aims: The target genome editing technology not only plays an important role in basic biology studies but also holds a great promise for potential clinical applications. The new generation of engineered nuclease RGEN (RNA Guided EndoNuclease) is much easier to construct and modify, and attracts more attentions. In the current study, we compared different plasmid construction strategies of Cas9-gRNA (guide RNA). Methods: Different plasmid construction strategies of Cas9-gRNA were compared. And more modifications were introduced into the plasmid construction strategy. Results: The plasmid construction efficiency of expressing the gRNA and Cas9 in one plasmid was lower than expressing them in two separate plasmids. However, they showed the similar genome editing efficiency. We further introduced the Golden-gate assembly and blue-white screening approaches into the Cas9-gRNA construction procedures, without the process of vector digestion and gel purification. Conclusions: Combing with the optimized gRNA structure (gRNA-BL) we identified before, we established one more cost-effective, time-saving and efficient plasmid construction strategy for Cas9-gRNA.

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14

Simon, Ian D., Nico van Rooijen, and John K. Rose. "Vesicular Stomatitis Virus Genomic RNA Persists In Vivo in the Absence of Viral Replication." Journal of Virology 84, no. 7 (December 23, 2009): 3280–86. http://dx.doi.org/10.1128/jvi.02052-09.

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ABSTRACT Our previous studies using intranasal inoculation of mice with vesicular stomatitis virus (VSV) vaccine vectors showed persistence of vector genomic RNA (gRNA) for at least 60 days in lymph nodes in the absence of detectable infectious virus. Here we show high-level concentration of virus and gRNA in lymph nodes after intramuscular inoculation of mice with attenuated or single-cycle VSV vectors as well as long-term persistence of gRNA in the lymph nodes. To determine if the persistence of gRNA was due to ongoing viral replication, we developed a tagged-primer approach that was critical for detection of VSV mRNA specifically. Our results show that VSV gRNA persists long-term in the lymph nodes while VSV mRNA is present only transiently. Because VSV transcription is required for replication, our results indicate that persistence of gRNA does not result from continuing viral replication. We also performed macrophage depletion studies that are consistent with initial trapping of VSV gRNA largely in lymph node macrophages and subsequent persistence elsewhere in the lymph node.

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15

Ivanovic, S., V. Bascarevic, M. Samardzic, L. Rasulic, and M. Misovic. "Avulzije zavrsnih grana trigeminalnog nerva." Acta chirurgica Iugoslavica 51, no. 4 (2004): 45–47. http://dx.doi.org/10.2298/aci0404045i.

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There are variety of surgical methods in treating trigeminal neuralgia. They can all be devided in two large groups: less invasive procedures and decopmressive procedures in the region of pontocerebelar angle. Peripheral neurectomy, exeresis or avulsion of peripheral branches of trigeminal nerv are methods for elderly patients with serious cardiopulmonal disturbances. We performed avulsion of peripheral branches at 58 patients, all older than 60 years. In 32 patients we did avulsion of only one of three branches of trigeminal nerv, while in 26 patients the combined avulsion of two branches was performed. There were no postoperative complications.

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16

Mullineaux, Conrad W. "Function and evolution of grana." Trends in Plant Science 10, no. 11 (November 2005): 521–25. http://dx.doi.org/10.1016/j.tplants.2005.09.001.

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17

Jiménez-González, Ogalla-García, García-Quintanilla, and García-Quintanilla. "Deciphering GRINA/Lifeguard1: Nuclear Location, Ca2+ Homeostasis and Vesicle Transport." International Journal of Molecular Sciences 20, no. 16 (August 16, 2019): 4005. http://dx.doi.org/10.3390/ijms20164005.

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The Glutamate Receptor Ionotropic NMDA-Associated Protein 1 (GRINA) belongs to the Lifeguard family and is involved in calcium homeostasis, which governs key processes, such as cell survival or the release of neurotransmitters. GRINA is mainly associated with membranes of the endoplasmic reticulum, Golgi, endosome, and the cell surface, but its presence in the nucleus has not been explained yet. Here we dissect, with the help of different software tools, the potential roles of GRINA in the cell and how they may be altered in diseases, such as schizophrenia or celiac disease. We describe for the first time that the cytoplasmic N-terminal half of GRINA (which spans a Proline-rich domain) contains a potential DNA-binding sequence, in addition to cleavage target sites and probable PY-nuclear localization sequences, that may enable it to be released from the rest of the protein and enter the nucleus under suitable conditions, where it could participate in the transcription, alternative splicing, and mRNA export of a subset of genes likely involved in lipid and sterol synthesis, ribosome biogenesis, or cell cycle progression. To support these findings, we include additional evidence based on an exhaustive review of the literature and our preliminary data of the protein–protein interaction network of GRINA.

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18

Chen, Kai, Liu Nan Yang, Chuan Lai, Dan Liu, and Ling-Qiang Zhu. "Role of Grina/Nmdara1 in the Central Nervous System Diseases." Current Neuropharmacology 18, no. 9 (October 6, 2020): 861–67. http://dx.doi.org/10.2174/1570159x18666200303104235.

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Glutamate receptor, ionotropic, N-methyl-D-aspartate associated protein 1 (GRINA) is a member of the NMDA receptors (NMDARs) and is involved in several neurological diseases, which governs the key processes of neuronal cell death or the release of neurotransmitters. Upregulation of GRINA has been reported in multiple diseases in human beings, such as major depressive disorder (MDD) and schizophrenia (SCZ), with which the underlying mechanisms remain elusive. In this review, we provide a general overview of the expression and physiological function of GRINA in the central nervous system (CNS) diseases, including stroke, depression ,epilepsy, SCZ, and Alzheimer’s disease (AD).

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19

Ismatullaeva, D. A., and Sh Ruzmatov. "Nosematosis of white silkworm and measures to combat with it." E3S Web of Conferences 258 (2021): 04016. http://dx.doi.org/10.1051/e3sconf/202125804016.

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This article presents the results of studies on the treatment of silkworm grena, slightly infected with nosematosis. As a result of treatment of grena with antibiotics and their combinations, a significant increase in the revitalization of grena and a decrease in the extensiveness of infection with nosematosis of revitalizing caterpillars is observed. It has been established that antibiotic chemicals, especially in combinations, contribute to the disinfection of grains from infectious diseases, in particular from nosematosis, and thereby improve the quality of silkworm grains. Which, in turn, helps to prevent the occurrence of diseases on the pedigree and industrial feedings of the silkworm

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20

Cruz-Reyes, Jorge, Alevtina Zhelonkina, Laura Rusche, and Barbara Sollner-Webb. "Trypanosome RNA Editing: Simple Guide RNA Features Enhance U Deletion 100-Fold." Molecular and Cellular Biology 21, no. 3 (February 1, 2001): 884–92. http://dx.doi.org/10.1128/mcb.21.3.884-892.2001.

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ABSTRACT Trypanosome RNA editing is a massive processing of mRNA by U deletion and U insertion, directed by trans-acting guide RNAs (gRNAs). A U deletion cycle and a U insertion cycle have been reproduced in vitro using synthetic ATPase (A6) pre-mRNA and gRNA. Here we examine which gRNA features are important for this U deletion. We find that, foremost, this editing depends critically on the single-stranded character of a few gRNA and a few mRNA residues abutting the anchor duplex, a feature not previously appreciated. That plus any base-pairing sequence to tether the upstream mRNA are all the gRNA needs to direct unexpectedly efficient in vitro U deletion, using either the purified editing complex or whole extract. In fact, our optimized gRNA constructs support faithful U deletion up to 100 times more efficiently than the natural gRNA, and they can edit the majority of mRNA molecules. This is a marked improvement of in vitro U deletion, in which previous artificial gRNAs were no more active than natural gRNA and the editing efficiencies were at most a few percent. Furthermore, this editing is not stimulated by most other previously noted gRNA features, including its potential ligation bridge, 3′ OH moiety, any U residues in the tether, the conserved structure of the central region, or proteins that normally bind these regions. Our data also have implications about evolutionary forces active in RNA editing.

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21

Mekler, Vladimir, Konstantin Kuznedelov, and Konstantin Severinov. "Quantification of the affinities of CRISPR–Cas9 nucleases for cognate protospacer adjacent motif (PAM) sequences." Journal of Biological Chemistry 295, no. 19 (April 1, 2020): 6509–17. http://dx.doi.org/10.1074/jbc.ra119.012239.

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The CRISPR/Cas9 nucleases have been widely applied for genome editing in various organisms. Cas9 nucleases complexed with a guide RNA (Cas9–gRNA) find their targets by scanning and interrogating the genomic DNA for sequences complementary to the gRNA. Recognition of the DNA target sequence requires a short protospacer adjacent motif (PAM) located outside this sequence. Given that the efficiency of target location may depend on the strength of interactions that promote target recognition, here we sought to compare affinities of different Cas9 nucleases for their cognate PAM sequences. To this end, we measured affinities of Cas9 nucleases from Streptococcus pyogenes, Staphylococcus aureus, and Francisella novicida complexed with guide RNAs (gRNAs) (SpCas9–gRNA, SaCas9–gRNA, and FnCas9–gRNA, respectively) and of three engineered SpCas9–gRNA variants with altered PAM specificities for short, PAM-containing DNA probes. We used a “beacon” assay that measures the relative affinities of DNA probes by determining their ability to competitively affect the rate of Cas9–gRNA binding to fluorescently labeled target DNA derivatives called “Cas9 beacons.” We observed significant differences in the affinities for cognate PAM sequences among the studied Cas9 enzymes. The relative affinities of SpCas9–gRNA and its engineered variants for canonical and suboptimal PAMs correlated with previous findings on the efficiency of these PAM sequences in genome editing. These findings suggest that high affinity of a Cas9 nuclease for its cognate PAM promotes higher genome-editing efficiency.

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22

Damasz, Barbara. "Genesis of grana and stroma thylakoids in leaf chloroplasts of four orchid species." Acta Societatis Botanicorum Poloniae 49, no. 3 (2014): 187–93. http://dx.doi.org/10.5586/asbp.1980.016.

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In the chloroplasts of orchid leaves (Paphiopedilum mastersianum Pfitz., Stanhopea tigrina Batem., Coelogyne cristata LDL and Cymbidium insigne Rolfe) grana stacks differentiate on the base of primary thylakoids. This process occurs by stratification due to overlapping of thylakoids, by their bending and by invagination of the membrane into the thylakoid. There also may form two membranes ending blindly at both ends, called "central contact zone" ("Kontaktzone") in the interior of the mother thylakoid. Thylakoid multiplication in the grana shacks takes place by the same processes; and also by the "overgrowth" of thylakoids over the stroma localized between the closely overlaid grana. The increase in the number of stroma thylakoids usually occurs by fusion of the flattend vesicles lying in rows in the stroma or by elongation of the grana thylakoids.

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23

Horton, Peter. "Hypothesis: Are grana necessary for regulation of light harvesting?" Functional Plant Biology 26, no. 7 (1999): 659. http://dx.doi.org/10.1071/pp99095.

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The importance of the functional flexibility of the light-harvesting complexes of photo-system II (LHCII) in accommodating the fluctuation in the balance between light input and metabolic capacity in plants is emphasised. This flexibility is provided for by a relatively complex assembly of protein subunits, the interactions between them being controlled by protonation, xanthophyll de-epoxidation and phosphorylation. It is suggested that the 3-dimensional order imposed upon this assembly of proteins by the grana is a vital aspect of the modulation of LHCII function. Grana establish the LHCII conformation needed for efficient light harvesting and help prevent the dense array of proteins from collapsing into a highly dissipative state. The grana then allow a controlled development of non-photochemical quenching under the driving force of violaxanthin de-epoxidation and protonation. In plants grown under different irradiances the different grana content and xanthophyll cycle pool size together allow maximum quantum yield in limiting light and an appropriate level of non-photochemical quenching in excess light.

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24

Mullally, Grace, Kara van Aelst, Mohsin M. Naqvi, Fiona M. Diffin, Tautvydas Karvelis, Giedrius Gasiunas, Virginijus Siksnys, and Mark D. Szczelkun. "5′ modifications to CRISPR–Cas9 gRNA can change the dynamics and size of R-loops and inhibit DNA cleavage." Nucleic Acids Research 48, no. 12 (June 4, 2020): 6811–23. http://dx.doi.org/10.1093/nar/gkaa477.

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Abstract A key aim in exploiting CRISPR–Cas is gRNA engineering to introduce additional functionalities, ranging from individual nucleotide changes that increase efficiency of on-target binding to the inclusion of larger functional RNA aptamers or ribonucleoproteins (RNPs). Cas9–gRNA interactions are crucial for complex assembly, but several distinct regions of the gRNA are amenable to modification. We used in vitro ensemble and single-molecule assays to assess the impact of gRNA structural alterations on RNP complex formation, R-loop dynamics, and endonuclease activity. Our results indicate that RNP formation was unaffected by any of our modifications. R-loop formation and DNA cleavage activity were also essentially unaffected by modification of the Upper Stem, first Hairpin and 3′ end. In contrast, we found that 5′ additions of only two or three nucleotides could reduce R-loop formation and cleavage activity of the RuvC domain relative to a single nucleotide addition. Such modifications are a common by-product of in vitro transcribed gRNA. We also observed that addition of a 20 nt RNA hairpin to the 5′ end of a gRNA still supported RNP formation but produced a stable ∼9 bp R-loop that could not activate DNA cleavage. Consideration of these observations will assist in successful gRNA design.

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Binda, Caroline S., Bep Klaver, Ben Berkhout, and Atze T. Das. "CRISPR-Cas9 Dual-gRNA Attack Causes Mutation, Excision and Inversion of the HIV-1 Proviral DNA." Viruses 12, no. 3 (March 18, 2020): 330. http://dx.doi.org/10.3390/v12030330.

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Although several studies demonstrated that the HIV proviral DNA can be effectively targeted and inactivated by the CRISPR-Cas9 system, the precise inactivation mechanism has not yet been analyzed. Whereas some studies suggested efficient proviral DNA excision upon dual-gRNA/Cas9 treatment, we previously demonstrated that hypermutation of the target sites correlated with permanent virus inactivation. To better understand the mechanism underlying HIV inactivation, we analyzed the proviral DNA upon Cas9 attack with gRNA pairs. We observed that dual-gRNA targeting resulted more frequently in target site mutation than fragment excision, while fragment inversion was rarely observed. The frequencies varied for different gRNA combinations without an obvious relationship with the distance between the target sites, indicating that other gRNA and target DNA characteristics influence the DNA cleavage and repair processes.

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Staehelin, L. Andrew, and Dominick J. Paolillo. "A brief history of how microscopic studies led to the elucidation of the 3D architecture and macromolecular organization of higher plant thylakoids." Photosynthesis Research 145, no. 3 (September 2020): 237–58. http://dx.doi.org/10.1007/s11120-020-00782-3.

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Abstract Microscopic studies of chloroplasts can be traced back to the year 1678 when Antonie van Leeuwenhoek reported to the Royal Society in London that he saw green globules in grass leaf cells with his single-lens microscope. Since then, microscopic studies have continued to contribute critical insights into the complex architecture of chloroplast membranes and how their structure relates to function. This review is organized into three chronological sections: During the classic light microscope period (1678–1940), the development of improved microscopes led to the identification of green grana, a colorless stroma, and a membrane envelope. More recent (1990–2020) chloroplast dynamic studies have benefited from laser confocal and 3D-structured illumination microscopy. The development of the transmission electron microscope (1940–2000) and thin sectioning techniques demonstrated that grana consist of stacks of closely appressed grana thylakoids interconnected by non-appressed stroma thylakoids. When the stroma thylakoids were shown to spiral around the grana stacks as multiple right-handed helices, it was confirmed that the membranes of a chloroplast are all interconnected. Freeze-fracture and freeze-etch methods verified the helical nature of the stroma thylakoids, while also providing precise information on how the electron transport chain and ATP synthase complexes are non-randomly distributed between grana and stroma membrane regions. The last section (2000–2020) focuses on the most recent discoveries made possible by atomic force microscopy of hydrated membranes, and electron tomography and cryo-electron tomography of cryofixed thylakoids. These investigations have provided novel insights into thylakoid architecture and plastoglobules (summarized in a new thylakoid model), while also producing molecular-scale views of grana and stroma thylakoids in which individual functional complexes can be identified.

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Menees, Thomas M. "RNA Lariat Debranching Enzyme as a Retroviral and Long-Terminal-Repeat Retrotransposon Host Factor." Annual Review of Virology 7, no. 1 (September 29, 2020): 189–202. http://dx.doi.org/10.1146/annurev-virology-012720-094902.

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Host cell factors are integral to viral replication. Human immunodeficiency virus 1 (HIV-1), the retroviral agent of acquired immune deficiency syndrome, requires several host factors for reverse transcription of the viral genomic RNA (gRNA) into DNA shortly after viral entry. One of these host factors is the RNA lariat debranching enzyme (Dbr1), which cleaves the 2′–5′ bond of branched and lariat RNAs. A recent study has revealed that Dbr1 cleaves HIV-1 gRNA lariats that form early after viral entry. Without Dbr1 activity, HIV-1 reverse transcription stalls, consistent with blockage of viral reverse transcriptase at gRNA branch points. These findings echo an earlier study with the long-terminal-repeat retrotransposon of Saccharomyces cerevisiae, Ty1, which is a retrovirus model. Currently, branching and debranching of viral gRNA are not widely recognized as features of HIV-1 replication, and the role of a gRNA lariat is not known. Future studies will determine whether these gRNA dynamics represent fundamental features of retroviral biology and whether they occur for other positive-sense RNA viruses.

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28

Coats, Lorenzo W. "Role of sulfolipds in grana thylakoid stacking." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 3 (August 12, 1990): 666–67. http://dx.doi.org/10.1017/s0424820100160881.

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In higher plants and algae, the thylakoid membranes are organized into closely appressed or stacked regions (grana), and a network of single interconnecting unstacked regions (stroma lamellae). The components and forces responsible for adhesion between thylakoids have been the subject of intense studies. Although these studies have added significantly to our knowledge of chloroplast membrane structure and function, they have failed to provide a clear rationale for grana membrane stacking. Completedestacking of grana occurs when chloroplasts are suspended in low-salt (10 mM NaCl) solution. Normal levels of stacked and un-stacked regions can be restored by incubation in salt solutions (150 mM NaCl).

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Haehnel, W., R. Ratajczak, and H. Robenek. "Lateral distribution and diffusion of plastocyanin in chloroplast thylakoids." Journal of Cell Biology 108, no. 4 (April 1, 1989): 1397–405. http://dx.doi.org/10.1083/jcb.108.4.1397.

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The lateral distribution of plastocyanin in the thylakoid lumen of spinach and pea chloroplasts was studied by combining immunocytochemical localization and kinetic measurements of P700+ reduction at high time resolution. In dark-adapted chloroplasts, the concentration of plastocyanin in the photosystem I containing stroma membranes exceeds that in photosystem II containing grana membranes by a factor of about two. Under these conditions, the reduction of P700+ with a halftime of 12 microseconds after a laser flash of saturating intensity indicates that to greater than 95% of total photosystem I a plastocyanin molecule is bound. An analysis of the labeling densities, the length of the different lumenal regions, and the total amounts of plastocyanin and P700 shows that most of the remaining presumable mobile plastocyanin is found in the granal lumen. This distribution of plastocyanin is consistent with a more negative surface charge density in the stromal than in the granal lumen. During illumination the concentration of plastocyanin in grana increases at the expense of that in stroma lamellae, indicating a light-driven diffusion from stroma to grana regions. Our observations provide evidence that a high concentration of plastocyanin in grana in the light favors the lateral electron transport from cytochrome b6/f complexes in appressed grana across the long distance to photosystem I in nonappressed stroma membranes.

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Arakawa, Hiroshi. "A method to convert mRNA into a gRNA library for CRISPR/Cas9 editing of any organism." Science Advances 2, no. 8 (August 2016): e1600699. http://dx.doi.org/10.1126/sciadv.1600699.

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The clustered regularly interspersed palindromic repeats (CRISPR)/Cas9 (CRISPR-associated protein 9) system is a powerful tool for genome editing that can be used to construct a guide RNA (gRNA) library for genetic screening. For gRNA design, one must know the sequence of the 20-mer flanking the protospacer adjacent motif (PAM), which seriously impedes experimentally making gRNA. I describe a method to construct a gRNA library via molecular biology techniques without relying on bioinformatics. Briefly, one synthesizes complementary DNA from the mRNA sequence using a semi-random primer containing a PAM complementary sequence and then cuts out the 20-mer adjacent to the PAM using type IIS and type III restriction enzymes to create a gRNA library. The described approach does not require prior knowledge about the target DNA sequences, making it applicable to any species.

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Rice, Breanna L., Timothy L. Lochmann, and Leslie J. Parent. "RNA-Binding Domains of Heterologous Viral Proteins Substituted for Basic Residues in the RSV Gag NC Domain Restore Specific Packaging of Genomic RNA." Viruses 12, no. 4 (March 27, 2020): 370. http://dx.doi.org/10.3390/v12040370.

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The Rous sarcoma virus Gag polyprotein transiently traffics through the nucleus, which is required for efficient incorporation of the viral genomic RNA (gRNA) into virus particles. Packaging of gRNA is mediated by two zinc knuckles and basic residues located in the nucleocapsid (NC) domain in Gag. To further examine the role of basic residues located downstream of the zinc knuckles in gRNA encapsidation, we used a gain-of-function approach. We replaced a basic residue cluster essential for gRNA packaging with heterologous basic residue motif (BR) with RNA-binding activity from either the HIV-1 Rev protein (Rev BR) or the HSV ICP27 protein (ICP27 BR). Compared to wild-type Gag, the mutant ICP27 BR and Rev BR Gag proteins were much more strongly localized to the nucleus and released significantly lower levels of virus particles. Surprisingly, both the ICP27 BR and Rev BR mutants packaged normal levels of gRNA per virus particle when examined in the context of a proviral vector, yet both mutants were noninfectious. These results support the hypothesis that basic residues located in the C-terminal region of NC are required for selective gRNA packaging, potentially by binding non-specifically to RNA via electrostatic interactions.

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ROSSI, FRANCA, VERONICA GATTO, GIANCARLO SABATTINI, and SANDRA TORRIANI. "An assessment of factors characterising the microbiology of Grana Trentino cheese, a Grana-type cheese." International Journal of Dairy Technology 65, no. 3 (April 18, 2012): 401–9. http://dx.doi.org/10.1111/j.1471-0307.2012.00844.x.

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Garbitt-Hirst, Rachel, Scott P. Kenney, and Leslie J. Parent. "Genetic Evidence for a Connection between Rous Sarcoma Virus Gag Nuclear Trafficking and Genomic RNA Packaging." Journal of Virology 83, no. 13 (April 15, 2009): 6790–97. http://dx.doi.org/10.1128/jvi.00101-09.

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ABSTRACT The packaging of retroviral genomic RNA (gRNA) requires cis-acting elements within the RNA and trans-acting elements within the Gag polyprotein. The packaging signal ψ, at the 5′ end of the viral gRNA, binds to Gag through interactions with basic residues and Cys-His box RNA-binding motifs in the nucleocapsid. Although specific interactions between Gag and gRNA have been demonstrated previously, where and when they occur is not well understood. We discovered that the Rous sarcoma virus (RSV) Gag protein transiently localizes to the nucleus, although the roles of Gag nuclear trafficking in virus replication have not been fully elucidated. A mutant of RSV (Myr1E) with enhanced plasma membrane targeting of Gag fails to undergo nuclear trafficking and also incorporates reduced levels of gRNA into virus particles compared to those in wild-type particles. Based on these results, we hypothesized that Gag nuclear entry might facilitate gRNA packaging. To test this idea by using a gain-of-function genetic approach, a bipartite nuclear localization signal (NLS) derived from the nucleoplasmin protein was inserted into the Myr1E Gag sequence (generating mutant Myr1E.NLS) in an attempt to restore nuclear trafficking. Here, we report that the inserted NLS enhanced the nuclear localization of Myr1E.NLS Gag compared to that of Myr1E Gag. Also, the NLS sequence restored gRNA packaging to nearly wild-type levels in viruses containing Myr1E.NLS Gag, providing genetic evidence linking nuclear trafficking of the retroviral Gag protein with gRNA incorporation.

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Read, L. K., H. U. Göringer, and K. Stuart. "Assembly of mitochondrial ribonucleoprotein complexes involves specific guide RNA (gRNA)-binding proteins and gRNA domains but does not require preedited mRNA." Molecular and Cellular Biology 14, no. 4 (April 1994): 2629–39. http://dx.doi.org/10.1128/mcb.14.4.2629.

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RNA editing in kinetoplastids probably employs a macromolecular complex, the editosome, that is likely to include the guide RNAs (gRNAs) which specify the edited sequence. Specific ribonucleoprotein (RNP) complexes which form in vitro with gRNAs (H. U. Göringer, D. J. Koslowsky, T. H. Morales, and K. D. Stuart, Proc. Natl. Acad. Sci. USA, in press) are potential editosomes or their precursors. We find that several factors are important for in vitro formation of these RNP complexes and identify specific gRNA-binding proteins present in the complexes. Preedited mRNA promotes the in vitro formation of the four major gRNA-containing RNP complexes under some conditions but is required for the formation of only a subcomponent of one complex. The 5' gRNA sequence encompassing the RYAYA and anchor regions and the 3' gRNA oligo(U) tail are both important in complex formation, since their deletion results in a dramatic decrease of some complexes and the absence of others. UV cross-linking experiments identify several proteins which are in contact with gRNA and preedited mRNA in mitochondrial extracts. Proteins of 25 and 90 kDa are highly specific for gRNAs, and the 90-kDa protein binds specifically to gRNA oligo(U) tails. The gRNA-binding proteins exhibit a differential distribution between the four in vitro-formed complexes. These experiments reveal several proteins potentially involved in RNA editing and indicate that multiple recognition elements in gRNAs are used for complex formation.

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Read, L. K., H. U. Göringer, and K. Stuart. "Assembly of mitochondrial ribonucleoprotein complexes involves specific guide RNA (gRNA)-binding proteins and gRNA domains but does not require preedited mRNA." Molecular and Cellular Biology 14, no. 4 (April 1994): 2629–39. http://dx.doi.org/10.1128/mcb.14.4.2629-2639.1994.

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RNA editing in kinetoplastids probably employs a macromolecular complex, the editosome, that is likely to include the guide RNAs (gRNAs) which specify the edited sequence. Specific ribonucleoprotein (RNP) complexes which form in vitro with gRNAs (H. U. Göringer, D. J. Koslowsky, T. H. Morales, and K. D. Stuart, Proc. Natl. Acad. Sci. USA, in press) are potential editosomes or their precursors. We find that several factors are important for in vitro formation of these RNP complexes and identify specific gRNA-binding proteins present in the complexes. Preedited mRNA promotes the in vitro formation of the four major gRNA-containing RNP complexes under some conditions but is required for the formation of only a subcomponent of one complex. The 5' gRNA sequence encompassing the RYAYA and anchor regions and the 3' gRNA oligo(U) tail are both important in complex formation, since their deletion results in a dramatic decrease of some complexes and the absence of others. UV cross-linking experiments identify several proteins which are in contact with gRNA and preedited mRNA in mitochondrial extracts. Proteins of 25 and 90 kDa are highly specific for gRNAs, and the 90-kDa protein binds specifically to gRNA oligo(U) tails. The gRNA-binding proteins exhibit a differential distribution between the four in vitro-formed complexes. These experiments reveal several proteins potentially involved in RNA editing and indicate that multiple recognition elements in gRNAs are used for complex formation.

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36

Sarni, Samantha, Banhi Biswas, Shuohui Liu, Erik D. Olson, Jonathan P. Kitzrow, Alan Rein, Vicki H. Wysocki, and Karin Musier-Forsyth. "HIV-1 Gag protein with or without p6 specifically dimerizes on the viral RNA packaging signal." Journal of Biological Chemistry 295, no. 42 (August 13, 2020): 14391–401. http://dx.doi.org/10.1074/jbc.ra120.014835.

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The HIV-1 Gag protein is responsible for genomic RNA (gRNA) packaging and immature viral particle assembly. Although the presence of gRNA in virions is required for viral infectivity, in its absence, Gag can assemble around cellular RNAs and form particles resembling gRNA-containing particles. When gRNA is expressed, it is selectively packaged despite the presence of excess host RNA, but how it is selectively packaged is not understood. Specific recognition of a gRNA packaging signal (Psi) has been proposed to stimulate the efficient nucleation of viral assembly. However, the heterogeneity of Gag–RNA interactions renders capturing this transient nucleation complex using traditional structural biology approaches challenging. Here, we used native MS to investigate RNA binding of wild-type (WT) Gag and Gag lacking the p6 domain (GagΔp6). Both proteins bind to Psi RNA primarily as dimers, but to a control RNA primarily as monomers. The dimeric complexes on Psi RNA require an intact dimer interface within Gag. GagΔp6 binds to Psi RNA with high specificity in vitro and also selectively packages gRNA in particles produced in mammalian cells. These studies provide direct support for the idea that Gag binding to Psi specifically promotes nucleation of Gag–Gag interactions at the early stages of immature viral particle assembly in a p6-independent manner.

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Bringaud, F., R. Stripecke, G. C. Frech, S. Freedland, C. Turck, E. M. Byrne, and L. Simpson. "Mitochondrial glutamate dehydrogenase from Leishmania tarentolae is a guide RNA-binding protein." Molecular and Cellular Biology 17, no. 7 (July 1997): 3915–23. http://dx.doi.org/10.1128/mcb.17.7.3915.

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To identify specific proteins interacting with guide RNAs (gRNAs) in mitochondrial ribonucleoprotein complexes from Leishmania tarentolae, fractionated and unfractionated mitochondrial extracts were subjected to UV cross-linking with added labeled gRNA and also with [alpha-32P]UTP-labeled endogenous RNA. An abundant 110-kDa protein (p110) localized in the T-V complex, which sediments in glycerol gradients at the leading edge of the 10S terminal uridylyltransferase peak, was found to interact with both types of labeled RNAs. The p110 protein was gel isolated and subjected to microsequence analysis, and the gene was cloned. The sequence revealed significant similarity with mitochondrial glutamate dehydrogenases. A polyclonal antiserum was raised against a recombinant fragment of the p110 gene and was used to demonstrate a stable and specific gRNA-binding activity by coimmunoprecipitation and competitive gel shift analyses. Complex formation was strongly inhibited by competition with poly(U) or by deletion or substitution of the gRNA 3' oligo(U) tail. Also, addition of a 3' oligo(U) tail to an unrelated transcript was sufficient for p110 binding. Both the gRNA-binding activity of the p110 protein and in vitro gRNA-independent and gRNA-dependent uridine insertion activities in the mitochondrial extract were inhibited by high concentrations of dinucleotides.

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38

Muszyński, Stanisław. "The ultrastructure of chloroplasts in variegata irregulare mutants of garden petunias (Petunia hybrida hort. superbissima)." Acta Societatis Botanicorum Poloniae 44, no. 1 (2015): 25–28. http://dx.doi.org/10.5586/asbp.1975.003.

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The ultrastructure of mutated chloroplasts in tetraploid garden petunias (Petunia hybrida hort. superbissima) was analyzed by electron microscopy. The formation of grana structure is inhibited after secondary thylacoids start forming. Rapid dezintegration of the structure is observed. It is suggested that a substance responsible for photostabilization of grana structure is lacking.

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39

Qiu, Xusheng, Yang Yu, Shengqing Yu, Yuan Zhan, Nana Wei, Cuiping Song, Yingjie Sun, Lei Tan, and Chan Ding. "Development of Strand-Specific Real-Time RT-PCR to Distinguish Viral RNAs during Newcastle Disease Virus Infection." Scientific World Journal 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/934851.

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Newcastle disease virus (NDV) causes large losses in the global fowl industry. To better understand NDV replication and transcription cycle, quantitative detection methods for distinguishing NDV genomic RNA (gRNA), antigenomic RNA (cRNA), and messenger RNA (mRNA) in NDV-infected cells are indispensible. Three reverse transcription primers were designed to specifically target the nucleoprotein (NP) region of gRNA, cRNA, and NP mRNA, and a corresponding real-time RT-PCR assay was developed to simultaneously quantify the three types of RNAs in NDV-infected cells. This method showed very good specificity, sensitivity, and reproducibility. The detection range of the assay was between5.5×102and1.1×109copies/μL of the target gene. These methods were applied to investigate the dynamics of the gRNA, cRNA, and mRNA synthesis in NDV La Sota infected DF-1 cells. The results showed that the copy numbers of viral gRNA, cRNA, and NP mRNA all exponentially increased in the beginning. The viral RNA copy number then plateaued at 10’h postinfection and gradually decreased from 16 h postinfection. No synthesis priority was observed between replication (gRNA and cRNA amounts) and transcription (mRNA amounts) during NDV infection. However, the cRNA accumulated more rapidly than gRNA, as the cRNA copy number was three- to tenfold higher than gRNA starting from 2 h postinfection.Conclusion. A real-time RT-PCR for absolute quantitation of specific viral RNA fragments in NDV-infected cells was developed for the first time. The development of this assay will be helpful for further studies on the pathogenesis and control strategies of NDV.

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Igo, Robert P., Sobomabo D. Lawson, and Kenneth Stuart. "RNA Sequence and Base Pairing Effects on Insertion Editing in Trypanosoma brucei." Molecular and Cellular Biology 22, no. 5 (March 1, 2002): 1567–76. http://dx.doi.org/10.1128/mcb.22.5.1567-1576.2002.

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ABSTRACT RNA editing inserts and deletes uridylates (U's) in kinetoplastid mitochondrial pre-mRNAs by a series of enzymatic steps. Small guide RNAs (gRNAs) specify the edited sequence. Editing, though sometimes extensive, is precise. The effects of mutating pre-mRNA and gRNA sequences in, around, and upstream of the editing site on the specificity and efficiency of in vitro insertion editing were examined. U's could be added opposite guiding pyrimidines, but guiding purines, particularly A's, were required for efficient ligation. A base pair between mRNA and gRNA immediately upstream of the editing site was not required for insertion editing, although it greatly enhanced its efficiency and accuracy. In addition, a gRNA/mRNA duplex upstream of the editing site enhanced insertion editing when it was close to the editing site, but prevented cleavage, and hence editing, when immediately adjacent to the editing site. Thus, several aspects of mRNA-gRNA interaction, as well as gRNA base pairing with added U's, optimize editing efficiency, although they are not required for insertion editing.

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Allen, Thomas E., Stefan Heidmann, RoseMary Reed, Peter J. Myler, H. Ulrich Göringer, and Kenneth D. Stuart. "Association of Guide RNA Binding Protein gBP21 with Active RNA Editing Complexes in Trypanosoma brucei." Molecular and Cellular Biology 18, no. 10 (October 1, 1998): 6014–22. http://dx.doi.org/10.1128/mcb.18.10.6014.

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ABSTRACT RNA editing in Trypanosoma brucei mitochondria produces mature mRNAs by a series of enzyme-catalyzed reactions that specifically insert or delete uridylates in association with a macromolecular complex. Using a mitochondrial fraction enriched for in vitro RNA editing activity, we produced several monoclonal antibodies that are specific for a 21-kDa guide RNA (gRNA) binding protein initially identified by UV cross-linking. Immunofluorescence studies localize the protein to the mitochondrion, with a preference for the kinetoplast. The antibodies cause a supershift of previously identified gRNA-specific ribonucleoprotein complexes and immunoprecipitate in vitro RNA editing activities that insert and delete uridylates. The immunoprecipitated material also contains gRNA-specific endoribonuclease, terminal uridylyltransferase, and RNA ligase activities as well as gRNA and both edited and unedited mRNA. The immunoprecipitate contains numerous proteins, of which the 21-kDa protein, a 90-kDa protein, and novel 55- and 16-kDa proteins can be UV cross-linked to gRNA. These studies indicate that the 21-kDa protein associates with the ribonucleoprotein complex (or complexes) that catalyze RNA editing.

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Martín Gutiérrez, Emilio. "El aprovechamiento de los recursos naturales: la grana en Andalucía occidental durante el siglo XV." Espacio Tiempo y Forma. Serie III, Historia Medieval, no. 34 (July 12, 2021): 501–22. http://dx.doi.org/10.5944/etfiii.34.2021.30044.

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En este artículo se estudia el aprovechamiento de la grana en Andalucía Occidental durante el siglo XV. El valor de la grana, que sirve para obtener el preciado color rojo para teñir lanas y sedas, permite reflexionar sobre la conexión existente entre los ecosistemas donde se recogía este recurso natural, los campesinos, la gobernanza de las ciudades y pueblos y el interés del mercado.

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Clement, Sandra L., Melissa K. Mingler, and Donna J. Koslowsky. "An Intragenic Guide RNA Location Suggests a Complex Mechanism for Mitochondrial Gene Expression in Trypanosoma brucei." Eukaryotic Cell 3, no. 4 (August 2004): 862–69. http://dx.doi.org/10.1128/ec.3.4.862-869.2004.

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ABSTRACT In Trypanosoma brucei, two classes of transcripts are produced from two distinct mitochondrial genome components. Guide RNAs (gRNAs) are usually minicircle encoded and exist as primary transcripts, while the maxicircle-encoded rRNAs and mRNAs are processed from a polycistronic precursor. The genes for the gRNAs gMURF2-II and gCYb(560) each have uncommon kinetoplast DNA (kDNA) locations that are not typically associated with transcription initiation events. We demonstrate that the conserved maxicircle gRNA gMURF2-II has an unusual location within the ND4 gene. This is the first report of a completely intragenic gene in kDNA. In addition, the gMURF2-II and ND4 transcripts are generated by distinctly different events; the ND4 mRNA is processed from a polycistronic precursor, while transcription of the gRNA initiates downstream of the 5′ end of the ND4 gene. The gCYb(560) gene has an atypical minicircle location in that it is not flanked by the inverted repeat sequences that surround the majority of minicircle gRNA genes. Our data indicate that the mature gCYb(560) gRNA is also a primary transcript and that the 5′-end heterogeneity previously observed for this gRNA is a result of multiple transcription initiation sites and not of imprecise 5′-end processing. Together, these data indicate that gRNA genes represent individual transcription units, regardless of their genomic context, and suggest a complex mechanism for mitochondrial gene expression in T. brucei.

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Easmin, Farhana, Naim Hassan, Yu Sasano, Keisuke Ekino, Hisataka Taguchi, and Satoshi Harashima. "gRNA-transient expression system for simplified gRNA delivery in CRISPR/Cas9 genome editing." Journal of Bioscience and Bioengineering 128, no. 3 (September 2019): 373–78. http://dx.doi.org/10.1016/j.jbiosc.2019.02.009.

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FILLING, CONSTANCE M. "Education Pioneer: William A. Grana, MD." Journal of the American Academy of Orthopaedic Surgeons 7, no. 3 (March 2013): 44. http://dx.doi.org/10.5435/00124635-201303010-00032.

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46

Arvidsson, Per-Ola, and Cecilia Sundby. "A model for the topology of the chloroplast thylakoid membrane." Functional Plant Biology 26, no. 7 (1999): 687. http://dx.doi.org/10.1071/pp99072.

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A model for the topological organization of the chloroplast thylakoid membrane is presented. A series of illustrations is provided, which outline a suggested 3-dimensional structure in cross-section and in full shape, which accounts both for the folding of one continuous membrane into multiple grana stacks as seen in cross-sectional electron micrographs and for the rapid reversible unfolding (destacking) of the grana stacks into lamellar sheets.

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Sanxter, Suzanne S., Harry Y. Yamamoto, David G. Fisher, and Harvey T. Chan Jr. "Development and decline of chloroplasts in exocarp of Carica papaya." Canadian Journal of Botany 70, no. 2 (February 1, 1992): 364–73. http://dx.doi.org/10.1139/b92-049.

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Photosynthetic and ultrastructural changes of plastids in papaya fruit exocarp (Carica papaya L.) from immature to ¾-ripe stages were characterized. Pulse-modulated chlorophyll fluorometry indicated primary photochemical yield developed maximally by the dead-green stage and did not decrease thereafter, even in ¾-ripe fruit. Nonphotochemical quenching, a reflection of ΔpH, also developed maximally by the dead-green stage but began declining at the ¼-ripe stage. The pattern of photochemical quenching, an indicator of oxidation of primary electron acceptors, was similar to nonphotochemical quenching. Chlorophyll a to b ratio was 2.25 in immature fruits and about 1.70 in more mature stages. Immature fruit plastids contained loosely appressed thylakoids with few grana, whereas more mature fruits up to the ¼-ripe stage had well-developed grana. Grana of ¾-ripe fruit were destacked; thylakoids often formed vesicles. These results, along with the fluorescence properties, suggest papaya-fruit chloroplasts are mature at the dead-green and mature-green stages and at these stages resemble chloroplasts in green leaf mesophyll tissue. When internal fruit ripening began (¼-ripe), photosynthetic and ultrastructural qualities of the exocarp remained relatively unchanged, indicating external ripeness lagged considerably behind internal ripeness. Although grana of ¾-ripe fruits were structurally disorganized, the ability for primary photochemistry was retained. Key words: chlorophyll fluorescence, ultrastructure, fruit development, ripening.

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Gorzelnik, Karl V., Zhicheng Cui, Catrina A. Reed, Joanita Jakana, Ry Young, and Junjie Zhang. "Asymmetric cryo-EM structure of the canonical Allolevivirus Qβ reveals a single maturation protein and the genomic ssRNA in situ." Proceedings of the National Academy of Sciences 113, no. 41 (September 26, 2016): 11519–24. http://dx.doi.org/10.1073/pnas.1609482113.

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Single-stranded (ss) RNA viruses infect all domains of life. To date, for most ssRNA virions, only the structures of the capsids and their associated protein components have been resolved to high resolution. Qβ, an ssRNA phage specific for the conjugative F-pilus, has a T = 3 icosahedral lattice of coat proteins assembled around its 4,217 nucleotides of genomic RNA (gRNA). In the mature virion, the maturation protein, A2, binds to the gRNA and is required for adsorption to the F-pilus. Here, we report the cryo-electron microscopy (cryo-EM) structures of Qβ with and without symmetry applied. The icosahedral structure, at 3.7-Å resolution, resolves loops not previously seen in the published X-ray structure, whereas the asymmetric structure, at 7-Å resolution, reveals A2 and the gRNA. A2 contains a bundle of α-helices and replaces one dimer of coat proteins at a twofold axis. The helix bundle binds gRNA, causing denser packing of RNA in its proximity, which asymmetrically expands the surrounding coat protein shell to potentially facilitate RNA release during infection. We observe a fixed pattern of gRNA organization among all viral particles, with the major and minor grooves of RNA helices clearly visible. A single layer of RNA directly contacts every copy of the coat protein, with one-third of the interactions occurring at operator-like RNA hairpins. These RNA–coat interactions stabilize the tertiary structure of gRNA within the virion, which could further provide a roadmap for capsid assembly.

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Anderson, Jan M. "Insights into the consequences of grana stacking of thylakoid membranes in vascular plants: a personal perspective." Functional Plant Biology 26, no. 7 (1999): 625. http://dx.doi.org/10.1071/pp99070.

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The striking structural architecture of thylakoid membranes of higher plant and some green algal chloroplasts that house the light harvesting and energy transducing functions of chloroplasts have evoked many hypotheses concerning the significance of grana. The differentiation of the thylakoids into grana and stroma membrane regions is a morphological reflection of the non-random distribution of the photosystems II and I between appressed and non-appressed membrane domains, which became known as lateral heterogeneity. In this overview, the first section deals with changing concepts regarding the distribution of the photosystems between stacked and unstacked thylakoid domains from a personal historical perspective. The remaining section describes some functional implications of the lateral separation of most PSII complexes in appressed membrane regions of grana stacks from PSI complexes, ATP synthase and auxiliary proteins located in non-appressed membrane domains.

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Trajano, Eleonora, Sandro Secutti, and Maria Elina Bichuette. "Natural history and population data of fishes in caves of the Serra do Ramalho karst area, Middle São Francisco basin, northeastern Brazil." Biota Neotropica 9, no. 1 (March 2009): 129–33. http://dx.doi.org/10.1590/s1676-06032009000100015.

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During the exploration and mapping of new caves in Serra do Ramalho karst area, southern Bahia state, cavers from the Grupo Bambuí de Pesquisas Espeleológicas - GBPE (Belo Horizonte) noticed the presence of troglomorphic catfishes (species with reduced eyes and/or melanic pigmentation), which we intensively investigated with regards to their ecology and behavior since 2005. Non-troglomorphic fishes regularly found in the studied caves were included in this investigation. We present here data on the natural history of two troglobitic (exclusively subterranean troglomorphic species) fishes - Rhamdia enfurnada Bichuette & Trajano, 2005 (Heptapteridae; Gruna do Enfurnado) and Trichomycterus undescribed species (Trichomycteridae; Lapa dos Peixes and Gruna da Água Clara), and non-troglomorphic Hoplias cf. malabaricus, probably a troglophile (able to form populations both in epigean and subterranean habitats) in the Gruna do Enfurnado, and Pimelodella sp., a species with a sink population in the Lapa dos Peixes.

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Journal articles on the topic 'Gröna'

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