Journal articles: 'Xaqa'

1

Harbaugh, Sam. "XAda." ACM SIGAda Ada Letters IV, no. 6 (May 1985): 27–31. http://dx.doi.org/10.1145/998421.998422.

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2

Shabani, Halil. "Objekte arkeologjike nga Xara /Objets archéologiques provenant de Xara." Iliria 21, no. 1 (1991): 239–42. http://dx.doi.org/10.3406/iliri.1991.1590.

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3

Picchi, Simone Cristina, Laís Moreira Granato, Maria Júlia Festa Franzini, Maxuel Oliveira Andrade, Marco Aurélio Takita, Marcos Antonio Machado, and Alessandra Alves de Souza. "Modified Monosaccharides Content of Xanthan Gum Impairs Citrus Canker Disease by Affecting the Epiphytic Lifestyle of Xanthomonas citri subsp. citri." Microorganisms 9, no. 6 (May 29, 2021): 1176. http://dx.doi.org/10.3390/microorganisms9061176.

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Xanthomonas citri subsp. citri (X. citri) is a plant pathogenic bacterium causing citrus canker disease. The xanA gene encodes a phosphoglucomutase/phosphomannomutase protein that is a key enzyme required for the synthesis of lipopolysaccharides and exopolysaccharides in Xanthomonads. In this work, firstly we isolated a xanA transposon mutant (xanA::Tn5) and analyzed its phenotypes as biofilm formation, xanthan gum production, and pathogenesis on the sweet orange host. Moreover, to confirm the xanA role in the impaired phenotypes we further produced a non-polar deletion mutant (ΔxanA) and performed the complementation of both xanA mutants. In addition, we analyzed the percentages of the xanthan gum monosaccharides produced by X. citri wild-type and xanA mutant. The mutant strain had higher ratios of mannose, galactose, and xylose and lower ratios of rhamnose, glucuronic acid, and glucose than the wild-type strain. Such changes in the saccharide composition led to the reduction of xanthan yield in the xanA deficient strain, affecting also other important features in X. citri, such as biofilm formation and sliding motility. Moreover, we showed that xanA::Tn5 caused no symptoms on host leaves after spraying, a method that mimetics the natural infection condition. These results suggest that xanA plays an important role in the epiphytical stage on the leaves that is essential for the successful interaction with the host, including adaptive advantage for bacterial X. citri survival and host invasion, which culminates in pathogenicity.

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Wu, Wenbo, Jiahong Liang, Xinyu Yao, and Baohong Liu. "Simulated Annealing Algorithm Combined with Chaos for Task Allocation in Real-Time Distributed Systems." Mathematical Problems in Engineering 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/151394.

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This paper addresses the problem of task allocation in real-time distributed systems with the goal of maximizing the system reliability, which has been shown to be NP-hard. We take account of the deadline constraint to formulate this problem and then propose an algorithm called chaotic adaptive simulated annealing (XASA) to solve the problem. Firstly, XASA begins with chaotic optimization which takes a chaotic walk in the solution space and generates several local minima; secondly XASA improves SA algorithm via several adaptive schemes and continues to search the optimal based on the results of chaotic optimization. The effectiveness of XASA is evaluated by comparing with traditional SA algorithm and improved SA algorithm. The results show that XASA can achieve a satisfactory performance of speedup without loss of solution quality.

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5

Long, Eric C. "Ni(II)·Xaa-Xaa-His Metallopeptide−DNA/RNA Interactions†." Accounts of Chemical Research 32, no. 10 (October 1999): 827–36. http://dx.doi.org/10.1021/ar980072j.

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6

Burkhardt, Bonnie. "First use of XAda methodology." ACM SIGAda Ada Letters V, no. 1 (July 1985): 79–88. http://dx.doi.org/10.1145/989981.989989.

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7

KASTURI, Lakshmi, Hegang CHEN, and Susan H. SHAKIN-ESHLEMAN. "Regulation of N-linked core glycosylation: use of a site-directed mutagenesis approach to identify Asn-Xaa-Ser/Thr sequons that are poor oligosaccharide acceptors." Biochemical Journal 323, no. 2 (April 15, 1997): 415–19. http://dx.doi.org/10.1042/bj3230415.

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N-linked glycosylation can profoundly affect protein expression and function. N-linked glycosylation usually occurs at the sequon Asn-Xaa-Ser/Thr, where Xaa is any amino acid residue except Pro. However, many Asn-Xaa-Ser/Thr sequons are glycosylated inefficiently or not at all for reasons that are poorly understood. We have used a site-directed mutagenesis approach to examine how the Xaa and hydroxy (Ser/Thr) amino acid residues in sequons influence core-glycosylation efficiency. We recently demonstrated that certain Xaa amino acids inhibit core glycosylation of the sequon, Asn37-Xaa-Ser, in rabies virus glycoprotein (RGP). Here we examine the impact of different Xaa residues on core-glycosylation efficiency when the Ser residue in this sequon is replaced with Thr. The core-glycosylation efficiencies of RGP variants with different Asn37-Xaa-Ser/Thr sequons were compared by using a cell-free translation/glycosylation system. Using this approach we confirm that four Asn-Xaa-Ser sequons are poor oligosaccharide acceptors: Asn-Trp-Ser, Asn-Asp-Ser, Asn-Glu-Ser and Asn-Leu-Ser. In contrast, Asn-Xaa-Thr sequons are efficiently glycosylated, even when Xaa = Trp, Asp, Glu or Leu. A comparison of the glycosylation status of Asn-Xaa-Ser and Asn-Xaa-Thr sequons in other glycoproteins confirms that sequons with Xaa = Trp, Asp, Glu or Leu are rarely glycosylated when Ser is the hydroxy amino acid residue, and that these sequons are unlikely to serve as glycosylation sites when introduced into proteins by site-directed mutagenesis.

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8

Qasımov, E. K., M. A. Əlibəyov, and S. Ə. İsrafilova. "Kriptarxizm zamanı xaya sükanı damarlarının strukturlarında və keçiriciklərində baş verən dəyişikliklərin morfoloji xarakteristikası. İşiq və elektron mikroskopik tədqiqat." Journal of Theoretical, Clinical and Experimental Morphology 1, no. 5 (June 17, 2019): 54–62. http://dx.doi.org/10.28942/jtcem.v1i5.86.

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Məqsəd. Hazırki, elmi tədqiqat işinin məqsədi nəzarət qrupu ilə müqayisədə kriptarxizm zamanı xaya sükanı damarlarında baş verən dəyişikliklərin işıq və elektron mikroskopik səviyyələrdə tədqiqidir. Material və metodlar. Хaya sükanından götürülmüş bioptatlar elektron mikroskopiyada qəbul olunmuş protokollar üzrə Araldit-Epon blokları, onlardan isə Leica EM UC7 ultratomunda (Almaniya) yarım- və ultanazik kəsiklər alıb rəngləndikdən sonra işıq (Primo Star - Almaniya) və elektron mikroskopunda (JEM-1400 – Yaponiya) baxılaraq şəkilləri çəkilmişdir. Nəticə. Damardaxili trombların formalaşması nəticəsində əzələvi venulaların mənfəzlərinin tutulması ilə formalaşan qan durğunluğu, yeni yaranmış kollateral damarda endotel hüceyrələri arasında aşkar edilən açıq əlaqələr, endotel hüceyrələrin yığılması nəticəsində onların periferik hissələrində formalaşan pəncərələrin və kaveolaların iştirakı ilə meydana cıxan transendotelial kanallar kriptarxizm zamanı xaya sükanı daxilində ödem mayesinin toplanmasına səbəb olur. Yekun. Qeyd etmək lazımdır ki, uzun müddət ərzində mikrosirkulyator sistemə aid edilən qan damarlarında filtirasiyanın yüksək səviyyədə saxlanılması xaya sükanın həcminin o səviyyəyə çatdirir ki, onun xaya ilə birlikdə qasıq kanalından keçərək xayalığa düşməsini qeyri mümkün edə bilər.

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9

Riis Hansen, Michael, Jesper Tranekjær Jørgensen, and Gert Dandanell. "Xanthosine Utilization in Salmonella enterica Serovar Typhimurium Is Recovered by a Single Aspartate-to-Glycine Substitution in Xanthosine Phosphorylase." Journal of Bacteriology 188, no. 11 (June 1, 2006): 4153–57. http://dx.doi.org/10.1128/jb.01926-05.

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ABSTRACT xapABR from Salmonella enterica was analyzed and compared with the corresponding Escherichia coli genes. xapB and xapR, but not xapA, encode functional proteins. An S. enterica XapA(Asp72Gly) mutant that restores the phosphorolytic activity was selected. The purified mutant enzyme has different kinetic constants than the E. coli enzyme but similar substrate specificity.

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10

Long, Eric C. "ChemInform Abstract: Ni(II)×Xaa-Xaa-His Metallopeptide - DNA/RNA Interactions." ChemInform 30, no. 52 (June 12, 2010): no. http://dx.doi.org/10.1002/chin.199952290.

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11

Das, Amit, Nandini Rangaraj, and Ramesh V. Sonti. "Multiple Adhesin-Like Functions of Xanthomonas oryzae pv. oryzae Are Involved in Promoting Leaf Attachment, Entry, and Virulence on Rice." Molecular Plant-Microbe Interactions® 22, no. 1 (January 2009): 73–85. http://dx.doi.org/10.1094/mpmi-22-1-0073.

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Xanthomonas oryzae pv. oryzae is the causal agent of bacterial blight of rice. We have used enhanced green fluorescent protein-tagged X. oryzae pv. oryzae cells in conjunction with confocal microscopy to monitor the role of several adhesin-like functions in bacterial adhesion to leaf surface and early stages of leaf entry. Mutations in genes encoding either the Xanthomonas adhesin-like protein A (XadA) or its paralog, Xanthomonas adhesin-like protein B (XadB), as well as the X. oryzae pv. oryzae homolog of Yersinia autotransporter-like protein H (YapH), exhibit deficiencies in leaf attachment or entry. A mutation in the X. oryzae pv. oryzae pilQ gene, which is predicted to encode the type IV pilus secretin, appears to have no effect on leaf attachment or entry. The xadA– mutant is deficient in the ability to cause disease following surface inoculation while the XadB, YapH, and PilQ functions are less important than XadA for this process. The xadA– and xadB– mutants have no effect on virulence following wound inoculation whereas the yapH– and pilQ– mutants are always virulence deficient following wound inoculation. Overall, these results indicate that multiple adhesin-like functions are involved in promoting virulence of X. oryzae pv. oryzae, with preferential involvement of individual functions at different stages of the disease process.

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12

CHO, Seung-Hyun, Jong-Uk NA, Hwan YOUN, Cheol-Sang HWANG, Chang-Hun LEE, and Sa-Ouk KANG. "Sepiapterin reductase producing l-threo-dihydrobiopterin from Chlorobium tepidum." Biochemical Journal 340, no. 2 (May 25, 1999): 497–503. http://dx.doi.org/10.1042/bj3400497.

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A novel type of NADPH-dependent sepiapterin reductase, which catalysed uniquely the reduction of sepiapterin to L-threo-dihydrobiopterin, was purified 533-fold from the cytosolic fraction of Chlorobium tepidum, with an overall yield of 3%. The native enzyme had a molecular mass of 55 kDa and SDS/PAGE revealed that the enzyme consists of two subunits with a molecular mass of 26 kDa. The enzyme was optimally active at pH 8.8 and 50 °C. Apparent Km values for sepiapterin and NADPH were 21 and 6.2 μM, respectively, and the kcat value was 5.0 s-1. Diacetyl could also serve as a substrate, with a Km of 4.0 mM. The inhibitory effects of N-acetylserotonin, N-acetyldopamine and melatonin were very weak. The Ki value of N-acetyldopamine was measured as 400 μM. The N-terminal amino acid sequence was revealed as Met-Lys-His-Ile-Leu-Leu-Ile-Thr-Gly-Ala-Xaa-Lys - Lys - Ile - Xaa - Arg - Ala - Ile - Ala - Leu - Glu - Xaa - Ala - Arg - Xaa-Xaa-Xaa-His-His-His-, which shared relatively high sequence similarity with other sepiapterin reductases.

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13

Wilson, Reggie. "Encountering Dance in Africa — and Nelisiwe Xaba." TDR/The Drama Review 64, no. 2 (June 2020): 16–17. http://dx.doi.org/10.1162/dram_a_00913.

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Travel to Africa over many years has revealed the depth and breadth of contemporary dance in South Africa. Within this scene, Nelisiwe Xaba stands out for crafting work from a woman’s perspective, joining several generations of artists who are asking complex questions on the relations of dance and politics.

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14

Turvey, Gerry. "‘Xala’ and the Curse of Neo-Colonialism." Screen 26, no. 3-4 (May 1, 1985): 75–88. http://dx.doi.org/10.1093/screen/26.3-4.75.

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15

FANG, Hao-Ming, and Yue WANG. "Characterization of iron-binding motifs in Candida albicans high-affinity iron permease CaFtr1p by site-directed mutagenesis." Biochemical Journal 368, no. 2 (December 1, 2002): 641–47. http://dx.doi.org/10.1042/bj20021005.

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A peptide motif Glu-Xaa-Xaa-Glu has been implicated in direct binding of ferric iron in several proteins involved in iron transport, sensing or storage. However, it is not known whether the motif alone is sufficient for iron binding and whether functional replacement of the conserved residues by other amino acids with similar properties is possible. We previously identified a Candida albicans iron permease, CaFtr1p, which contains five Glu-Xaa-Xaa-Glu motifs [Ramanan and Wang (2000) Science 288, 1062—1065]. In this study, we investigated the role of each of these motifs in iron uptake by site-directed mutagenesis. Substitution of Ala for any one of the two Glu residues in Glu-Gly-Leu-Glu158—161 abolished iron-uptake activity, while the same substitution in any of the other four motifs had little effect, indicating that only the motif at position 158—161 is required for iron transport. We then evaluated the importance of each of the residues within and immediately adjacent to this motif in iron uptake. The permease remained active when any one of the Glu residues was replaced by Asp, while it became inactive when both were replaced. We also found that the amino acid immediately in front of Glu-Gly-Leu-Glu158—161 must be either Arg or Lys. In addition, substitution of any of the two residues in the middle with several structurally distinct amino acids had no detectable effect on iron uptake. Here we propose to extend the iron-binding motif to Arg/Lys-Glu/Asp-Xaa-Xaa-Glu or Arg/Lys-Glu-Xaa-Xaa-Glu/Asp, which may serve as a guide for the identification of potential iron-binding sites in proteins.

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16

Huang, Xiaofen, Mary E. Pieczko, and Eric C. Long. "Combinatorial Optimization of the DNA Cleaving Ni(II)·Xaa-Xaa-His Metallotripeptide Domain†." Biochemistry 38, no. 7 (February 1999): 2160–66. http://dx.doi.org/10.1021/bi982587o.

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17

Nociti, Letícia A. S., Margarete Camargo, Júlio Rodrigues Neto, Fabrício J. B. Francischini, and José Belasque Júnior. "Agressividade de linhagens de Xanthomonas axonopodis pv. aurantifolii Tipo C em lima ácida 'Galego'." Fitopatologia Brasileira 31, no. 2 (April 2006): 140–46. http://dx.doi.org/10.1590/s0100-41582006000200003.

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O presente trabalho objetivou gerar informações referentes à agressividade de linhagens de Xanthomonas axonopodis pv. aurantifolii Tipo C(Xaa-C), produtoras (PP) e não produtoras de pigmento (NP) escuro em meio de cultura, comparativamente a X. axonopodis pv. citri Tipo A (Xac) . Os tratamentos foram formados por 14 linhagens, sendo sete de Xaa-C PP, cinco Xaa-C NP, e duas linhagens de Xac. As linhagens foram inoculadas através de ferimentos, em folhas de lima ácida 'Galego' (Citrus aurantifolia Swingle), com agulha previamente mergulhada em uma suspensão de células bacterianas (10(7) UFC/mL). Foram realizadas dez repetições para cada tratamento, representadas por uma planta cada. As plantas foram mantidas em casa de vegetação durante todo o experimento. As linhagens diferiram entre si quanto ao período de incubação, diâmetro e populações bacterianas das lesões e, comparativamente, Xaa-C NP mostraram-se mais agressivas do que Xaa-C PP. Algumas linhagens induziram sintomas que diferiram quanto à presença e extensão de anasarca, halo amarelo e saliência do tecido necrosado.

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Dumas, R., M. Lebrun, and R. Douce. "Isolation, characterization and sequence analysis of a full-length cDNA clone encoding acetohydroxy acid reductoisomerase from spinach chloroplasts." Biochemical Journal 277, no. 2 (July 15, 1991): 469–75. http://dx.doi.org/10.1042/bj2770469.

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Acetohydroxy acid reductoisomerase (AHRI), the second enzyme in the parallel isoleucine/valine-biosynthetic pathway, catalyses an unusual two-step reaction in which the substrate, either 2-acetolactate or 2-aceto-2-hydroxybutyrate, is converted via an alkyl migration and an NADPH-dependent reduction to give 2,3-dihydroxy-3-methylbutyrate or 2,3-dihydroxy-3-methylvalerate respectively. We have isolated and characterized a full-length cDNA from a lambda gt11 spinach library encoding the complete acetohydroxy acid reductoisomerase protein precursor. The 2050-nucleotide sequence contains a 1785-nucleotide open reading frame. The derived amino acid sequence indicates that the protein precursor consists of 595 amino acid residues including a presequence peptide of 72 amino acid residues. The N-terminal sequence of the first 16 amino acid residues of the purified AHRI confirms the identity of the cDNA. The derived amino acid sequence from this open reading frame shows 23% identity with the deduced amino acid sequences of the Escherichia coli and Saccharomyces cerevisiae AHRI proteins. There are two blocks of conserved amino acid residues in these three proteins. One of these is a sequence similar to the ‘fingerprint’ region of the NAD(P)H-binding site found in a large number of NAD(P)H-dependent oxidoreductases. The other, a short sequence (Lys-Xaa-Xaa-Xaa-Xaa-Xaa-Xaa-Xaa-Ser-His-Gly-Phe) containing the amino acids lysine and histidine, could well be the catalytic site of the first step of the AHRI reaction. Southern-blot analysis indicated that AHRI is encoded by a single gene per haploid genome of about 7.5 kbp containing at least four introns.

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Stokoe, D., B. Caudwell, P. T. W. Cohen, and P. Cohen. "The substrate specificity and structure of mitogen-activated protein (MAP) kinase-activated protein kinase-2." Biochemical Journal 296, no. 3 (December 15, 1993): 843–49. http://dx.doi.org/10.1042/bj2960843.

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The substrate specificity of mitogen-activated protein (MAP) kinase-activated protein kinase-2 (MAPKAP kinase-2) was investigated by using synthetic peptides related to the N-terminus of glycogen synthase. The minimum sequence required for efficient phosphorylation was found to be Xaa-Xaa-Hyd-Xaa-Arg-Xaa-Xaa-Ser-Xaa-Xaa, where Hyd is a bulky hydrophobic residue (Phe > Leu > Val >> Ala), and the peptide Lys-Lys-Phe-Asn-Arg-Thr-Leu-Ser-Val-Ala was phosphorylated with a Km of 9.3 microM and Vmax. of 10 mumol/min per mg. MAPKAP kinase-1 (a homologue of ribosomal protein S6 kinase) also requires an arginine three residues N-terminal to the serine (position n-3), but not a hydrophobic residue at position n-5. Neither MAPKAP kinase-1 nor MAPKAP kinase-2 could tolerate a proline residue at position n + 1, indicating that their specificities do not overlap with that of MAP kinase. The specificity of calmodulin-dependent protein kinase-II resembled that of MAPKAP kinase-2, except that it could tolerate replacement of the arginine by a lysine and the phosphorylation-site serine by a threonine residue. Partial cDNAs encoding MAPKAP kinase-2 were isolated from rabbit and human skeletal muscle and human teratocarcinoma libraries, and Northern-blotting experiments revealed a single 3.3 kb mRNA transcript present at similar levels in six human tissues examined. The catalytic domain was most similar (35-40% identity) to calmodulin-dependent protein kinases II and IV, phosphorylase kinase, putative serine kinase H1 and the C-terminal domain of MAPKAP kinase-1, which form one branch of the protein kinase phylogenetic tree. The sequence N-terminal to the catalytic domain is proline-rich and contains two putative SH3-binding sites. The threonine residue phosphorylated by MAP kinase lies immediately C-terminal to the catalytic domain and is followed by a nuclear localization signal, Lys-Lys-(Xaa)10-Lys-Arg-Arg-Lys-Lys, near the C-terminus.

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Hsieh, Cheng-Hong, Tzu-Yuan Wang, Chuan-Chuan Hung, Chia-Ling Jao, You-Liang Hsieh, Si-Xian Wu, and Kuo-Chiang Hsu. "In silico, in vitro and in vivo analyses of dipeptidyl peptidase IV inhibitory activity and the antidiabetic effect of sodium caseinate hydrolysate." Food & Function 7, no. 2 (2016): 1122–28. http://dx.doi.org/10.1039/c5fo01324k.

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The frequency (A), a novel in silico parameter, was developed by calculating the ratio of the number of truncated peptides with Xaa-proline and Xaa-alanine to all peptide fragments from a protein hydrolyzed with a specific protease.

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21

Feil, Helene, William S. Feil, and Steven E. Lindow. "Contribution of Fimbrial and Afimbrial Adhesins of Xylella fastidiosa to Attachment to Surfaces and Virulence to Grape." Phytopathology® 97, no. 3 (March 2007): 318–24. http://dx.doi.org/10.1094/phyto-97-3-0318.

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The role of fimbrial and afimbrial adhesins of Xylella fastidiosa in biofilm formation was assessed by visualization of cell aggregates of mutant strains after incubation on glass surfaces. FimA- or FimF- fimbrial mutants adhered as solitary cells at a slightly lesser frequency to glass surfaces than the parental strain; however, cell aggregates were not formed, unlike the wild-type strain. Conversely, whereas the XadA- and HxfB- nonfimbrial mutants also exhibited a much lower frequency of adherence to glass surfaces than the wild-type strain, most of the cells retained on the surfaces were in cell aggregates of different sizes, much like that of the parental strain. Neither fimbrial or afimbrial mutants formed a mature biofilm on the sides of flasks of broth cultures, unlike the dense biofilm formed by the wild-type strain. Although FimA- and FimF- mutants did not form cell aggregates on glass surfaces when incubated as individual strains, aggregates of a FimA- or FimF- mutant were observed when co-incubated with either a XadA- mutant or HxfB- mutant, respectively. These results are consistent with a model in which the fimbrial adhesins FimA and FimF are involved preferentially in cell-to-cell aggregate formation whereas the afimbrial adhesions XadA and HxfB preferentially contribute to initial cell binding to surfaces, whereupon further cell aggregation can occur. In each of five separate experiments, FimA, FimF, XadA, and HxfB mutants of X. fastidiosa all were less virulent to grape than the corresponding wild-type strain. Fimbrial and afimbrial mutants might produce a reduced biofilm within vessels of grape and, hence, be deficient in various cell-density-dependent traits required for movement through the plant and, thus, virulence.

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22

Burger, Bibi. "Queer Africa 2 (Makhosazana Xaba and Karen Martin)." Tydskrif vir Letterkunde 55, no. 2 (August 30, 2018): 172–74. http://dx.doi.org/10.17159/2309-9070/tvl.v.55i2.4858.

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23

Wittrock, Eike. "Fremdes Erbe: Nelisiwe Xaba and German Dance Heritage." TDR/The Drama Review 64, no. 2 (June 2020): 38–53. http://dx.doi.org/10.1162/dram_a_00916.

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Nelisiwe Xaba’s Fremde Tänze opens up questions of contemporary implications of dance history. Situated within the cultural politics of dance in Germany, especially funding programs such as Tanzfonds Erbe (dance funds heritage), Xaba’s work and the curatorial frame of the Julius-Hans-Spiegel-Zentrum project contest the notion of “cultural heritage” from a postcolonial perspective.

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24

Mulvey, Laura. "Xala,Ousmane Sembene 1976: The carapace that failed." Third Text 5, no. 16-17 (September 1991): 19–37. http://dx.doi.org/10.1080/09528829108576325.

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Mulvey, Laura. "Xala, Ousmane Sembene (1974): The Carapace That Failed." Camera Obscura: Feminism, Culture, and Media Studies 11, no. 1 (1993): 48–70. http://dx.doi.org/10.1215/02705346-11-1_31-48.

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Mowitt, John. "Sembene Ousmanes Xala: Postcoloniality and Foreign Film Languages." Camera Obscura: Feminism, Culture, and Media Studies 11, no. 1 (1993): 71–95. http://dx.doi.org/10.1215/02705346-11-1_31-71.

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27

Imagawa, M., T. Onozawa, K. Okumura, S. Osada, T. Nishihara, and M. Kondo. "Characterization of metallothionein cDNAs induced by cadmium in the nematode Caenorhabditis elegans." Biochemical Journal 268, no. 1 (May 15, 1990): 237–40. http://dx.doi.org/10.1042/bj2680237.

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cDNAs of metallothioneins (MTs) in the nematode Caenorhabditis elegans were characterized. The MT-II clone encodes 62 amino acid residues and the predicted Mr is 6462. The MT-I clone contains an additional 12 residues at the C-terminal end, and the predicted Mr is 7959. There is a considerable similarity between MT-I and MT-II. Both of these proteins are cysteine-rich and, with a few exceptions, show a good alignment of cysteine residues. No obvious sequence relationship in the coding region was discernible between C. elegans MTs and mammalian MTs, aside from Cys-Cys, Cys-Xaa-Cys, and Cys-Xaa-Xaa-Xaa-Cys segments. However, 3′-untranslated region of cDNAs of C. elegans MT-I and -II have some consensus sequences found in mammalian MT cDNAs, suggesting that these regions may have some roles in the regulation of MT-gene expression.

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Korecki, P., M. Tolkiehn, K. M. Dąbrowski, and D. V. Novikov. "Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure." Journal of Synchrotron Radiation 18, no. 6 (September 15, 2011): 851–61. http://dx.doi.org/10.1107/s0909049511030688.

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Projections of the atomic structure around Nb atoms in a LiNbO3single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using NbKfluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples.

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Litera, Jaroslav, Jan Weber, Ivana Křížová, Iva Pichová, Jan Konvalinka, Martin Fusek, and Milan Souček. "Peptide Inhibitors of Aspartic Proteinases with Hydroxyethylene Isostere Replacement of Peptide Bond. II. Preparation of Pseudotetrapeptides Derived from Diastereoisomeric 5-Amino-2-benzyl-4-hydroxy-6-phenylhexanoic Acids." Collection of Czechoslovak Chemical Communications 63, no. 4 (1998): 541–48. http://dx.doi.org/10.1135/cccc19980541.

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Twelve pseudotetrapeptides, Boc-NHCH(CH2Ph)CH(OH)CH2CH(CH2Ph) CO-Xaa-Phe-NH2 9-11, were prepared by [(benzotriazol-1-yl)oxy]tris(dimethylamino)phosphonium hexafluorophosphate-mediated couplings of diastereoisomeric O-silylated (2R or 2S,4R or 4S,5S)-2-benzyl-5-(tert-butoxycarbonyl)amino-4-hydroxy-6-phenylhexanoic acids 1 with dipeptides H-Xaa-Phe-NH2 (Xaa = Gln, Glu(OBzl) or Ile) 3-5, followed by O-deprotection. Pseudotetrapeptides 9-11 were tested for inhibition of aspartic proteinases secreted by Candida albicans and C. tropicalis. The level of inhibition of both yeast proteinases was very low, contrasting with the nanomolar IC50 values obtained for inhibition of HIV-1 proteinase.

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30

Vangrysperre, W., J. Van Damme, J. Vandekerckhove, C. K. De Bruyne, R. Cornelis, and H. Kersters-Hilderson. "Localization of the essential histidine and carboxylate group in d-xylose isomerases." Biochemical Journal 265, no. 3 (February 1, 1990): 699–705. http://dx.doi.org/10.1042/bj2650699.

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D-Xylose isomerases from different bacterial strains were chemically modified with histidine and carboxylate-specific reagents. The active-site residues were identified by amino acid sequence analysis of peptides recognized by differential peptide mapping on ligand-protected and unprotected derivatized enzyme. Both types of modified residues were found to cluster in a region with consensus sequence: Phe-His-Asp-Xaa-Asp-Xaa-Xaa-Pro-Xaa-Gly, conserved in all D-xylose isomerases studied so far. These results are consistent with the recently published X-ray data of the enzyme active centre from Streptomyces rubiginosus showing hydrogen bond formation between Asp-57 and His-54 which locks the latter in one tautomeric form. A study of the pH-dependence of the kinetic parameters suggests the participation of a histidine group in the substrate-binding but not in the isomerization process. Comparison of the N-terminal amino acid sequences of several D-xylose isomerases further revealed a striking homology among the Actinomycetaceae enzymes and identifies them as a specific class of D-xylose isomerases.

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Böttcher, Olaf, Nils Heineking, and Dieter Hermann Sutter. "14N Quadrupole Coupling in the Rotational Spectra of Cyclopropylamine and Cyclopropyl Cyanide." Zeitschrift für Naturforschung A 44, no. 7 (July 1, 1989): 655–58. http://dx.doi.org/10.1515/zna-1989-0709.

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Abstract The 14N hyperfine structure in the rotational spectra of cyclopropylamine and cyclopropyl cyanide has been reinvestigated by microwave Fourier transform spectroscopy. The observed quadrupole coupling constants in units of MHz are: Xaa = 2.3338(18), Xbb = 1.7874(20), Xcc = −4.1209(20) for cyclopropylamine and Xaa = −3.4536(35), Xbb= 1.7468(51), Xcc= 1.7068(51) for cyclopropyl cyanide.

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32

Haft, Daniel H. "A strain-variable bacteriocin in Bacillus anthracis and Bacillus cereus with repeated Cys-Xaa-Xaa motifs." Biology Direct 4, no. 1 (2009): 15. http://dx.doi.org/10.1186/1745-6150-4-15.

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33

Lygo, Barry, and Carl N. Rudd. "Synthesis of Xaa-Gly-Xaa′ keto-methylene tri-peptide isosteres incorporating phenylalanine, tyrosine and valine units." Tetrahedron Letters 36, no. 20 (May 1995): 3577–80. http://dx.doi.org/10.1016/0040-4039(95)00564-s.

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34

Wennemers, Helma, and Tobias Schnitzer. "Thieme Chemistry Journals Awardees – Where Are They Now? A Stereoselective Tripeptide Catalyst for Conjugate Addition Reactions of Acetophenones to Dicyanoolefins." Synlett 28, no. 11 (March 10, 2017): 1282–86. http://dx.doi.org/10.1055/s-0036-1588964.

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Peptides of the type H-Pro-Pro-Xaa-NH2 were evaluated as catalysts for conjugate addition reactions of acetophenones to cyanoolefins. Tripeptide H-d-Pro-Pro-Glu-NH2 with a carboxylic acid moiety in the side chain of Xaa was identified as a catalyst that provides γ,γ-dicyanoacetophenones in yields of up to 90% and stereoselectivies of up to 88:12 er.

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35

Young, Hershini. "Inhabiting Inherited Structures of Representation." TDR/The Drama Review 64, no. 2 (June 2020): 78–87. http://dx.doi.org/10.1162/dram_a_00920.

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Looking at how Tanztheater traditionally exploited the notion of Orientalism and Primitivism reveals how Nelisiwe Xaba refocuses the audience’s gaze, drawing attention to the role that representational modes have played in consolidating racism.

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36

Iyam, David Uru. "The Silent Revolutionaries: Ousmane Sembene's Emitai, Xala, and Ceddo." African Studies Review 29, no. 4 (December 1986): 79. http://dx.doi.org/10.2307/524007.

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37

Sorensen. "Naturalism and Temporality in Ousmane Sembène's Xala." Research in African Literatures 41, no. 2 (2010): 222. http://dx.doi.org/10.2979/ral.2010.41.2.222.

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38

Mushengyezi, Aaron. "Reimaging Gender and African Tradition? Ousmane Sembene's Xala revisited." Africa Today 51, no. 1 (2004): 47–62. http://dx.doi.org/10.1353/at.2004.0070.

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Dima, Vlad. "Women and posters as heterotopias in Ousmane Sembene’s Xala." Journal of African Cinemas 5, no. 2 (October 1, 2013): 137–48. http://dx.doi.org/10.1386/jac.5.2.137_1.

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40

MAKSEL, Danuta, Paul R. GOOLEY, James D. SWARBRICK, Andrzej GURANOWSKI, Christine GANGE, G. Michael BLACKBURN, and Kenwyn R. GAYLER. "Characterization of active-site residues in diadenosine tetraphosphate hydrolase from Lupinus angustifolius." Biochemical Journal 357, no. 2 (July 9, 2001): 399–405. http://dx.doi.org/10.1042/bj3570399.

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Site-directed mutagenesis has been used to characterize the functions of key amino acid residues in the catalytic site of the ‘nudix’ hydrolase, (asymmetrical) diadenosine 5′,5‴-P1,P4-tetraphosphate (Ap4A) hydrolase (EC 3.6.1.17) from Lupinus angustifolius, the three-dimensional solution structure of which has recently been solved. Residues within the nudix motif, Gly-(Xaa)5-Glu-(Xaa)7-Arg-Glu-Uaa-Xaa-(Glu)2-Xaa-Gly (where Xaa represents unspecified amino acids and Uaa represents the bulky aliphatic amino acids Ile, Leu or Val) conserved in ‘nudix enzymes’, and residues important for catalysis from elsewhere in the molecule, were mutated and the expressed proteins characterized. The results reveal a high degree of functional conservation between lupin asymmetric Ap4A hydrolase and the 8-oxo-dGTP hydrolase from Escherichia coli. Charged residues in positions equivalent to those that ligate an enzyme-bound metal ion in the E. coli 8-oxo-dGTP hydrolase [Harris, Wu, Massiah and Mildvan (2000) Biochemistry 39, 1655–1674] were shown to contribute to catalysis to similar extents in the lupin enzyme. Mutations E55Q, E59Q and E125Q all reduced kcat markedly, whereas mutations R54Q, E58Q and E122Q had smaller effects. None of the mutations produced a substantial change in the Km for Ap4A, but several extensively modified the pH-dependence and fluoride-sensitivities of the hydrolase. It was concluded that the precisely positioned glutamate residues Glu-55, Glu-59 and Glu-125 are conserved as functionally significant components of the hydrolytic mechanism in both of these members of the nudix family of hydrolases.

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Zhou, Suping, Roger Sauve, and Fur-Chi Chen. "Structure and Temperature Regulated Expression of a Cysteine Proteinase Gene in Pachysandra terminalis Sieb. & Zucc." Journal of the American Society for Horticultural Science 132, no. 1 (January 2007): 97–101. http://dx.doi.org/10.21273/jashs.132.1.97.

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A cysteine proteinase gene (DQ403257) with an open reading frame of 1125 base pairs was isolated from Pachysdandra terminalis. The primary translated peptide has a predicted length of 374 amino acids, pI (isoelectric point) of 5.70, and molecular mass of 40.9 kDa. The Peptidase_C1 domain is between residue 141 and 367. The proteinase has a conserved motif Gly-Xaa-Thy-Xaa-Phe-Xaa-Asn in the pro region. Sequence comparison shows that the deduced peptide shares 82% identity with the cysteine proteinase RD19a precursor (RD19) (accession P43296) from Arabidopsis thaliana (L.) Heynh. Real-time quantitative reverse-transcriptase–polymerase chain reaction revealed that the gene is induced by treatments of 1 to 7 days of darkness, 2 hours and 3 to 7 days at 5 °C, and 3 days at 38 °C.

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42

Gooley, Andrew A., Brendan J. Classon, Rolf Marschalek, and Keith L. Williams. "Glycosylation sites identified by detection of glycosylated amino acids released from Edman degradation: The identification of Xaa-Pro-Xaa-Xaa as a motif for Thr-O-glycosylation." Biochemical and Biophysical Research Communications 178, no. 3 (August 1991): 1194–201. http://dx.doi.org/10.1016/0006-291x(91)91019-9.

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43

Watly, Joanna, Aleksandra Hecel, Paulina Kolkowska, Henryk Kozlowski, and Magdalena Rowinska-Zyrek. "Poly-Xaa Sequences in Proteins - Biological Role and Interactions with Metal Ions: Chemical and Medical Aspects." Current Medicinal Chemistry 25, no. 1 (January 22, 2018): 22–48. http://dx.doi.org/10.2174/0929867324666170428104928.

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Background: The understanding of the bioinorganic and coordination chemistry of metalloproteins containing unusual poly-Xaa sequences, in which a single amino acid is repeated consecutively, is crucial for describing their metal binding-structure-function relationship, and therefore also crucial for understanding their medicinal potential. To the best of our knowledge, this is the first systematic review on metal complexes with polyXaa sequences. Methods: We performed a thorough search of high quality peer reviewed literature on poly-Xaa type of sequences in proteins, focusing on their biological importance and on their interactions with metal ions. Results: 228 papers were included in the review. More than 70% of them discussed the role of metal complexes with the studied types of sequences. In this work, we showed numerous medically important and chemically fascinating examples of possible ‘poly-Xaa' metal binding sequences. Conclusion: Poly-Xaa sequences, in which a single amino acid is repeated consecutively, are often not only tempting binding sites for metal ions, but very often, together with the bound metal, serve as structure determinants for entire proteins. This, in turn, can have consequences for the whole organism. Such sequences in bacterial metal chaperones can be a possible target for novel, antimicrobial therapeutics.

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44

Hayes Edwards, Brent. "Transplanted Exoticism." TDR/The Drama Review 64, no. 2 (June 2020): 75–78. http://dx.doi.org/10.1162/dram_a_00919.

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Nelisiwe Xaba’s Fremde Tänze is a remarkable exercise in transplanted exoticism. Its trenchant critique of German imaginings of racialized and eroticized Others unavoidably took on different meanings when Xaba performed it in Chicago in the fall of 2017.

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45

LYGO, B., and C. N. RUDD. "ChemInform Abstract: Synthesis of Xaa-Gly-Xaa′ Keto-Methylene Tripeptide Isosteres Incorporating Phenylalanine, Tyrosine, and Valine Units." ChemInform 26, no. 36 (August 17, 2010): no. http://dx.doi.org/10.1002/chin.199536228.

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46

GUERRA, PAULA. "UM LUGAR SEM LUGAR... NO ROCK PORTUGUÊS." Outros Tempos: Pesquisa em Foco - História 17, no. 29 (February 12, 2020): 181–204. http://dx.doi.org/10.18817/ot.v17i29.757.

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Neste artigo procuraremos analisar os motivos para a invisibilidade feminina no rockportuguêscomo aspeto central da construção da feminilidade da contemporaneidade portuguesa. Noutro lugar demonstramos a existência de uma consistente dominação masculina no rockportuguês. Parece que as mulheres apenas são recordadas pela lente dos estereótipos dominantes, ou como meras namoradas, acompanhantes e atores sociais submissos em espaço público. Para combater esse esquecimento propomos, primeiro, um estado da arte que cruze género e estudos juvenis, depois uma curta apresentação do estado da participação feminina no rock português, para depois nos centrarmos na questão central do artigo: a história de vida de Xana, vocalista dos RádioMacau. Uma trajetória paradigmática não só de uma músicaportuguesa, mas de toda a construção da feminilidade no mundo das artes e da cultura na história recente de Portugal. Palavras-chave: Portugal.Rock.Dominação Masculina. Género. Xana. Rádio Macau. A PLACE WITH NO PLACE... IN PORTUGUESE ROCK Abstract: In this article we analyze the reasons for female invisibility in Portuguese rock as a central aspect in the construction of the femininity of the Portuguesecontemporaneity. Elsewhere we showed the existence of a consistent male domination in Portuguese rockscene.It seems that the women are barely remembered through the dominant stereotypeslenses, such as mere lovers, companions and submissive social actressesin public space. To combat this invisibility, we propose, first, a state of the art about gender and youth studies, then a brief presentation of the state of female participation in Portuguese rock, and then the central issue of the article: the life historyof Xana, vocalist of Radio Macau.A paradigmatic trajectory not only of Portuguese music, but of the entire construction of femininity in the world of arts and culture in recent Portuguese history. Keywords: Portugal. Rock. Male Domination. Gender. Xana. Radio Macau. UN LUGAR SIN LUGAR ... EN EL ROCK PORTUGUÉS Resumen: En este artículo analizaremos las razones de la invisibilidad femenina en el punk portugués. En otras partes4demostramos la existencia de una profunda misoginia en las letras punk portuguesas.Parece que las mujeres solo son recordadasa través de la lente de los estereotipos dominantes, o como meras novias, chaperonas y actores sociales sumisos en el espacio público. Para combatir este olvido, proponemos, primero, un estado del arte que cruza los estudios de género y juventud, luego una breve presentación del estado de la participación femenina en el rockportugués, y luego nos centramos en el tema central del artículo: la historia de vida de Xana, la vocalista de Rádio Macau.Una trayectoria paradigmática no solo de la música portuguesa, sino de toda la construcción de la feminidad en el mundo de las artes y la cultura en la historia portuguesa reciente.Palabras clave: Portugal. Rock. Dominación Masculina.Gender.Xana.Rádio Macau.

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47

Leyh-Bouille, M., J. Van Beeumen, S. Renier-Pirlot, B. Joris, M. Nguyen-Distèche, and J. M. Ghuysen. "The Streptomyces K15 DD-peptidase/penicillin-binding protein. Active site and sequence of the N-terminal region." Biochemical Journal 260, no. 2 (June 1, 1989): 601–4. http://dx.doi.org/10.1042/bj2600601.

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The N-terminal region of the Streptomyces K15 DD-peptidase/penicillin-binding protein shows high homology with that of other penicillin-interactive proteins or domains. The active-site serine residue of the conserved tetrad Ser-Xaa-Xaa-Lys occurs at position 35. There is no indication for the presence of a signal peptide or an N-terminal hydrophobic sequence, suggesting that the Streptomyces K15 enzyme is probably anchored to the membrane by a C-terminal peptide segment.

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Orlean, Peter. "Enzymes that recognize dolichols participate in three glycosylation pathways and are required for protein secretion." Biochemistry and Cell Biology 70, no. 6 (June 1, 1992): 438–47. http://dx.doi.org/10.1139/o92-067.

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We have explored the structure, function, and membrane topography of enzymes that recognize dolichols and participate in glycosylation pathways in the endoplasmic reticulum. Enzymes that interact with dolichols, including dolichyl phosphate mannose (Dol-P-Man) synthase and UDP-GlcNAc:Dol-P GlcNAc-1-P-transferase, revealed a conserved amino acid sequence in membrane-spanning regions. The consensus is Phe-Ile/Val-Xaa-Phe/Tyr-Xaa-Xaa-Ile-Pro-Phe-Xaa-Phe/Tyr, and we propose it is involved in dolichol recognition. We have used yeast mutants to demonstrate the role of dolichols in three glycosylation pathways. At its nonpermissive temperature, a Dol-P-Man synthase mutant (dpm1) was blocked in N-glycosylation, O-mannosylation, and glycosyl phosphoinositol membrane anchoring of protein, most likely because Dol-P-Man serves as mannosyl donor in all three pathways. The secretion mutant sec59 has a similar phenotype to dpm1, and the presence of a dolichol recognition sequence in the SEC59 protein gave a clue to its defect, which is in dolichol kinase. Comparison of yeast glycosylation mutants suggests that the ability to carry out N-glycosylation alone is sufficient to allow yeast to secrete glycoproteins and that an N-linked saccharide of a minimum size must be attached to proteins for cells to be able to secrete them and maintain a functional secretory pathway.Key words: glycosylation, secretion, glycosyl phosphatidylinositol, yeast mutants.

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Hong, Mi Seon. "Critiques of neocolonialism in francophone african cinema: Ousmane Sembene's XALA." Journal of international area studies 14, no. 1 (April 30, 2010): 373. http://dx.doi.org/10.18327/jias.2010.04.14.1.373.

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Ballart, Jordi. "Saying Catalan Words in Spanish: Social Representations of Xava Catalan." Hispanic Research Journal 3, no. 3 (October 2002): 191–208. http://dx.doi.org/10.1179/hrj.2002.3.3.191.

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Journal articles on the topic 'Xaqa'

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