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1.
Trop Biomed ; 40(1): 115-123, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37356011

RESUMO

Toxoplasma gondii, the etiologic agent of toxoplasmosis, infects about 30 - 50% of the world population. The currently available anti-Toxoplasma agents have serious limitations. The present study aimed to investigate the effects of two antimalarials; buparvaquone (BPQ) and chloroquine (CQ), on immunocompromised mice with chronic cerebral toxoplasmosis, using spiramycin as a reference drug. The assessed parameters included the estimation of mortality rates (MR) among mice of the different study groups, in addition to the examination of the ultrastructural changes in the brain tissues by transmission electron microscopy. The results showed that only CQ treatment could decrease the MR significantly with zero deaths, while both spiramycin and BPQ caused an insignificant reduction of MR compared to the infected non-treated group. All the used drugs decreased the number of mature ruptured cysts significantly compared to the infected non-treated group, while only CQ increased the number of atrophic and necrotic cysts significantly. Furthermore, both spiramycin and BPQ improved the microvasculopathy and neurodegeneration accompanying the infection with different degrees of reactive astrocytosis and neuronal damage with the best results regarding the repair of the microvascular damage with less active glial cells, and normal neurons in the CQ-treated group. In conclusion, this study sheds light on CQ and its excellent impact on treating chronic cerebral toxoplasmosis in an immunocompromised mouse model.


Assuntos
Cistos , Espiramicina , Toxoplasma , Toxoplasmose Animal , Toxoplasmose Cerebral , Animais , Camundongos , Espiramicina/farmacologia , Espiramicina/uso terapêutico , Cloroquina/farmacologia , Cloroquina/uso terapêutico , Modelos Animais de Doenças , Toxoplasmose Animal/tratamento farmacológico
2.
Vet World ; 11(10): 1510-1515, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30532510

RESUMO

AIM: The aim of this work was to detect chicken B-cell marker 6 (ChB6) gene in some native breeds in Egypt and find the relationship between founded genes in these different breeds to determine the resistance of native Egyptian breeds of chicken to Marek's disease (MD). MATERIALS AND METHODS: A total of 14 different chicken breeds (30 each) including ten native breeds in addition to SPF Lohmann, High Line, Bovans, and Roodiland were used. Blood samples were collected for the detection of (ChB6) by polymerase chain reaction (PCR) assay and sequenced to determine the presence or absence of ChB6 gene. Experimental infection was done using local field isolated MD virus (MDV) of 11 (1 day old) unvaccinated chick breeds having no maternal antibodies against MDV. Ten breeds of them carry ChB6 gene, eight breeds were native, and the rest two breeds were SPF Lohmann and High Line in addition to a group of ChB6 gene-lacking breed (Bovans) were infected. Spleen samples were collected from all infected breeds at 20th, 25th, 30th, 35th, and 40th weeks post-infection and tested by PCR assay for the detection of MDV. Furthermore, at 40th week post-infection, tumorized spleen sample of Bovans breed was collected and prepared for examination by transmission electron microscope (TEM) to confirm the presence of MDV. RESULTS: Our results revealed the positivity of 10 out of 14 breeds (Gimmizah, Sinai, Dandarawi, Fayoumi, Golden Montazah, Matrouh, Beheri, Dokki, SPF Lohmann, and High Line) to the presence of ChB6 gene and resistance to MDV infection, while the Bovans, Mandarah, Inshas and Roodiland breeds lack the ChB6 gene and are susceptible to MDV infection. The collected spleen samples revealed negative for the presence of challenged MDV by PCR in 10 breeds (Gimmizah, Sinai, Dandarawi, Fayoumi, Golden Montazah, Matrouh, Beheri, Dokki, SPF Lohmann, and High Line) and positive for Bovans breed. TEM is used to confirm MDV infection in Bovans group which demonstrated tumors. CONCLUSION: The study confirms the relationship between the presence of ChB6 gene in our native breeds and the absence of tumors.

3.
Genet Mol Res ; 13(2): 2886-905, 2014 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-24682982

RESUMO

The domesticated one-humped Arabian camel, Camelus dromedarius, is one of the most important animals in the Arabian Peninsula. Most of its life, this animal is exposed to both intrinsic and extrinsic genotoxic factors that are known to cause gross metabolic alterations in many organisms. This study determined the full length coding sequence of 3 cytochrome P450s cDNAs; namely, CYP450 1A1, CYP450 2C and CYP450 3A using reverse transcription polymerase chain reaction. The C. dromedarius CYP450s 1A1, 2C, and 3A have open reading frames of 1563, 1473, and 1566 bp and cDNAs that encode proteins of 520, 490, and 521 amino acid residues, respectively. The molecular weights calculated for CYP1A1, 2C, and 3A were found to be 58.651, 56.03, and 58.594 kDa, while the predicted calculated isoelectric points using a computer algorithm were 7.315, 6.579, and 9.46. The deduced amino acid sequences of these CYPs showed the membrane anchored signal peptide, the conserved proline-rich amino terminus and the characteristic heme-binding signature localized near the carboxy terminus of the protein.


Assuntos
Camelus/genética , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP3A/genética , Sistema Enzimático do Citocromo P-450/genética , Animais , Clonagem Molecular , DNA Complementar/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
4.
J Virol Methods ; 193(2): 337-40, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23811231

RESUMO

Bovine coronavirus (BCoV) is an economically significant cause of calf scours and winter dysentery of adult cattle, and may induce respiratory tract infections in cattle of all ages. Early diagnosis of BCoV helps to diminish its burden on the dairy and beef industry. Real-time RT-PCR assay for the detection of BCoV has been described, but it is relatively expensive, requires well-equipped laboratories and is not suitable for on-site screening. A novel assay, using reverse transcription recombinase polymerase amplification (RT-RPA), for the detection of BCoV is developed. The BCoV RT-RPA was rapid (10-20 min) and has an analytical sensitivity of 19 molecules. No cross-reactivity with other viruses causing bovine gastrointestinal and/or respiratory infections was observed. The assay performance on clinical samples was validated by testing 16 fecal and 14 nasal swab specimens and compared to real-time RT-PCR. Both assays provided comparable results. The RT-RPA assay was significantly more rapid than the real-time RT-PCR assay. The BCoV RT-RPA constitutes a suitable accurate, sensitive and rapid alternative to the common measures used for BCoV diagnosis. In addition, the use of a portable fluorescence reading device extends its application potential to use in the field and point-of-care diagnosis.


Assuntos
Doenças dos Bovinos/diagnóstico , Infecções por Coronavirus/veterinária , Coronavirus Bovino/isolamento & purificação , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Recombinases/metabolismo , Transcrição Reversa , Animais , Bovinos , Doenças dos Bovinos/virologia , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/virologia , Coronavirus Bovino/genética , Fezes/virologia , Cavidade Nasal/virologia , Sistemas Automatizados de Assistência Junto ao Leito , Sensibilidade e Especificidade , Fatores de Tempo , Medicina Veterinária/métodos , Virologia/métodos
5.
Virus Genes ; 47(2): 311-6, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23842723

RESUMO

The current study was conducted to isolate and characterize Newcastle disease virus (NDV) from recent outbreaks affecting poultry farms in Egypt between 2011 and 2012. Trachea, spleen, liver, proventriculus and caecal tonsils were collected from clinically infected NDV ten different vaccinated broiler farms in Fayoum, Behira and Giza Provinces. Inoculation of all the collected samples in 10-day-old embryonated chicken specific-pathogen-free eggs resulted in isolation of haemagglutinating agents in three samples. These haemagglutinating agents were confirmed as NDV by real-time reverse transcription polymerase chain reaction (rt RT-PCR) using matrix (M) gene-specific primers. The deduced amino acid sequences of the fusion protein revealed that one isolate possessed the motif (112)RRQKRF(117) at the cleavage site, indicating that this isolate is velogenic genotype, whereas the other two isolates carries the motif (112)GRQGRL(117) indicating they are lentogenic genotype. The phylogenetic analysis revealed that the velogenic genotype isolate clustered with published class II genotype VII sub genotype d NDVs and closely related to Middle East isolates, whereas the other two isolates clustered with published class II genotype II NDVs. The spread of velogenic genotype strain to Egypt via Middle Eastern countries is likely to be the source of infection.


Assuntos
Doença de Newcastle/virologia , Vírus da Doença de Newcastle/classificação , Vírus da Doença de Newcastle/genética , Doenças das Aves Domésticas/virologia , Estruturas Animais/virologia , Animais , Galinhas , Análise por Conglomerados , Surtos de Doenças , Egito/epidemiologia , Genótipo , Epidemiologia Molecular , Dados de Sequência Molecular , Doença de Newcastle/epidemiologia , Vírus da Doença de Newcastle/isolamento & purificação , Filogenia , Doenças das Aves Domésticas/epidemiologia , RNA Viral/genética , Análise de Sequência de DNA
6.
Food Chem Toxicol ; 48(11): 3221-6, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20813150

RESUMO

The acute toxicity (LD(50)) of insecticide methomyl and its effects on male reproduction in rats were carried out. Methomyl was given orally to male rats daily for 65 successive days at two doses (0.5 and 1.0 mg kg(-1) b.wt., corresponding to 1/40 and 1/20 LD(50)) alone and in combination with folic acid (1.1 mg kg(-1) b.wt., corresponding to acceptable daily intake, ADI). Fertility index, weight of sexual organs, semen picture, serum testosterone level and histopathology of testes were the parameters used to evaluate the reproductive efficiency of treated rats. The reversibility of methomyl effects was also studied after 65 days post-administration. The oral LD(50) of methomyl was 20.0 mg kg(-1) b.wt. in male rats. Methomyl significantly decreased the fertility index, weight of testes and accessory male sexual glands, serum testosterone level and sperm motility and count, but increased sperm cell abnormality. It induced testicular lesions characterized by moderate to severe degenerative changes of seminiferous tubules and incomplete arrest of spermatogenesis. These toxic effects were not persistent (reversible). Coadministration of folic acid with methomyl decreased its reproductive toxicity. A great attention should be taken during field application of methomyl to avoid its deleterious effects in farm animals and occupationally exposed humans.


Assuntos
Fertilidade/efeitos dos fármacos , Ácido Fólico/farmacologia , Inseticidas/toxicidade , Metomil/toxicidade , Complexo Vitamínico B/farmacologia , Administração Oral , Animais , Genitália/efeitos dos fármacos , Genitália/patologia , Dose Letal Mediana , Masculino , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica/efeitos dos fármacos , Contagem de Espermatozoides , Motilidade dos Espermatozoides/efeitos dos fármacos , Motilidade dos Espermatozoides/fisiologia , Espermatozoides/anormalidades , Espermatozoides/efeitos dos fármacos , Espermatozoides/fisiologia , Testículo/efeitos dos fármacos , Testículo/patologia , Testosterona/sangue
7.
Food Chem Toxicol ; 48(10): 2920-4, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20667464

RESUMO

The acute toxicity of methanolic and watery extracts of Zingiber officinale (ZO) roots in mice and their effects on fertility of male diabetic rats were carried out. The fertility experiment was done on six groups of male rats one of them was kept as normal control, while the others were rendered diabetic by subcutaneous injection of alloxan (120 mg kg(-1)). One group was left as diabetic control, while the others were given orally either methanolic (100 and 200 mg kg(-1)) or watery extract (150 and 300 mg kg(-1)) for 65 consecutive days. The results showed that no mortalities occur when both extracts were given orally to mice in doses up to 5 g kg(-1) b.wt. Both extracts increased fertility index, sexual organs weight, serum testosterone level and sperm motility and count. Histopathological examination of the testes of diabetic rats showed mild to moderate degenerative changes of spermatogenic cells, diffuse edema and incomplete arrest of spermatogenesis. Treatment with ZO extracts caused alleviation of the testicular lesions that appeared in non-treated diabetic rats. Conclusively, extracts of ZO have high safety in mice and intake of ZO roots as a drink may be useful for diabetic patients who suffer from sexual impotency.


Assuntos
Diabetes Mellitus Experimental/fisiopatologia , Fertilidade/efeitos dos fármacos , Zingiber officinale/toxicidade , Animais , Diabetes Mellitus Experimental/complicações , Epididimo/citologia , Feminino , Infertilidade/tratamento farmacológico , Dose Letal Mediana , Masculino , Metanol , Camundongos , Tamanho do Órgão/efeitos dos fármacos , Raízes de Plantas/química , Ratos , Ratos Sprague-Dawley , Comportamento Sexual Animal/efeitos dos fármacos , Solventes , Contagem de Espermatozoides , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatogênese/efeitos dos fármacos , Testículo/anatomia & histologia , Testículo/efeitos dos fármacos , Testosterona/sangue , Água
8.
Pharmacol Res ; 50(2): 137-42, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15177301

RESUMO

The effect of alpha-tocopherol, simvastatin and both on male fertility in hypercholesterolemic rats was studied. Induction of hypercholesterolemia was done by feeding rats on a diet containing 1% cholesterol for 30 days. Hypercholesterolemic rats were orally given alpha-tocopherol (3 mg kg(-1) BW) or simvastatin (1 mg kg(-1) BW) or both for 65 days. Fertility index, serum testosterone level, sex organs weight, semen analysis and histopathological examination of testes, seminal vesicles and prostate glands were the parameters used to evaluate the reproductive efficiency of rats. In hypercholesterolemic rats (control +ve), there was a marked decrease in fertility index, testicular weight, sperm cell count, and percentages of sperm motility and viability associated with a significant increase in sperm cell abnormalities. Oral administration of either alpha-tocopherol or simvastatin to hypercholesterolemic rats for 65 days significantly improved the fertility index, testicular weight and semen quality. Concomitant administration of alpha-tocopherol and simvastatin to hypercholesterolemic rats markedly increased fertility index and sperm motility and viability associated with a significant reduction of sperm cell abnormalities. Histopathological examination revealed that testes of hypercholesterolemic rats (control +ve) had degenerated, non-functioning and atrophied seminiferous tubules associated with arrest of spermatogenesis. Oral administration of alpha-tocopherol and simvastatin concomitantly to hypercholesterolemic rats resulted in active mature and full functioning seminiferous tubules. In conclusion, concomitant administration of alpha-tocopherol and simvastatin to hypercholesterolemic male rats improved their reproductive efficiency and produced additional protection against reduced fertility induced by hypercholesterolemia.


Assuntos
Hipercolesterolemia/tratamento farmacológico , Infertilidade Masculina/tratamento farmacológico , Sinvastatina/farmacologia , alfa-Tocoferol/farmacologia , Administração Oral , Animais , Cápsulas , Colesterol na Dieta/administração & dosagem , Colesterol na Dieta/efeitos adversos , Colesterol na Dieta/farmacologia , Dieta , Esquema de Medicação , Quimioterapia Combinada , Feminino , Gelatina , Hipercolesterolemia/induzido quimicamente , Hipercolesterolemia/complicações , Infertilidade Masculina/complicações , Masculino , Tamanho do Órgão/efeitos dos fármacos , Próstata/efeitos dos fármacos , Ratos , Reprodução/efeitos dos fármacos , Reprodução/fisiologia , Sêmen/química , Sêmen/efeitos dos fármacos , Túbulos Seminíferos/efeitos dos fármacos , Túbulos Seminíferos/patologia , Sinvastatina/administração & dosagem , Sinvastatina/uso terapêutico , Contagem de Espermatozoides/métodos , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatozoides/anormalidades , Espermatozoides/efeitos dos fármacos , Testículo/química , Testículo/efeitos dos fármacos , Testículo/ultraestrutura , Testosterona/sangue , Fatores de Tempo , alfa-Tocoferol/administração & dosagem , alfa-Tocoferol/uso terapêutico
9.
Egypt J Immunol ; 10(1): 89-102, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-15726722

RESUMO

In the present study, the immunopathogenicity of chicken anemia virus (CAV) vaccinal strain was studied in one-day-old specific-pathogen-free (SPF) chicks. Hematocrit values, histopathological changes in haemopioetic and lymphoid organs, ELISA for CAV antibodies and PCR for CAV genome were used as testing assays for the study. Vaccinated chicks showed signs of anemia, lower hematocrit values and histopathological lesions in liver in the form of hepatocytes swelling to Centro lobular necrosis and apoptosis. Histopathology change in spleen (depletion of lymphocytes and apoptosis) and thymus (depletion of thymocytes and apoptosis) together with variable degrees of seroconversion rate were observed along the 10 weeks of the experiment indicating 2 waves of immune response in vaccinated chicks compared to the control non-vaccinated group. Detection of CAV-DNA in the liver of vaccinated chicks indicated the presence of the virus, when the antibody levels were decreased in some chicks. There was a consistent correlation between the 4 parameters used. It is concluded that the attenuated CAV vaccine strain induces anemia and lesions in the lymphoid organs. The histopathology and PCR are useful tools for evaluation and quality assurance of CAV vaccines.


Assuntos
Vírus da Anemia da Galinha/imunologia , Vírus da Anemia da Galinha/patogenicidade , Galinhas , Infecções por Circoviridae/veterinária , Doenças das Aves Domésticas/imunologia , Anemia/etiologia , Anemia/veterinária , Animais , Animais Recém-Nascidos , Anticorpos Antivirais/biossíntese , Vírus da Anemia da Galinha/genética , Vírus da Anemia da Galinha/isolamento & purificação , Infecções por Circoviridae/imunologia , Infecções por Circoviridae/prevenção & controle , DNA Viral/genética , DNA Viral/isolamento & purificação , Hematócrito , Fígado/patologia , Fígado/virologia , Doenças das Aves Domésticas/prevenção & controle , Organismos Livres de Patógenos Específicos , Baço/patologia , Timo/patologia , Vacinas Atenuadas/farmacologia , Vacinas Atenuadas/toxicidade , Vacinas Virais/farmacologia , Vacinas Virais/toxicidade
10.
Carbohydr Res ; 334(1): 61-70, 2001 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-11470251

RESUMO

Six cyclobutanetetraone poly(arylhydrazones) have been treated with acids and bases, and the structures of the resulting anions and cations studied by UV-Vis absorption and NMR spectroscopy. In acid media, all the hydrazones studied formed cations, which exhibited bathochromic shifts due to the extension of their resonance systems. However, in bases, only some (those which could enolize) formed anions that exhibited hypsochromic shifts; the others were unaltered.


Assuntos
Ânions/química , Cátions/química , Hidrazonas/química , Polímeros/química , Espectrometria de Massas , Ressonância Magnética Nuclear Biomolecular , Espectrofotometria Ultravioleta
11.
J Egypt Soc Parasitol ; 29(2): 431-49, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10605495

RESUMO

Sixty cases ranging in age between 18-30 years old, 50 of them were suffering from schistosomiasis haematobium, they were selected from in- and out-patient clinic of Theodor Bilharz Research Institute. Patients were divided into three groups, 20 infected and not treated, 20 infected and treated then exposed again to infection and 10 were completely treated. The authors have a fourth group to serve healthy control. Blood samples were collected to count eosinophil percentage and absolute eosinophil count. Urine samples were collected to 1-study eosinophiluria by slide film staining with Leishman's stain, and 2- to count number of ova excreted in 10 ml urine by urine filtration technique. Eosinophila and eosinophiluria > 5% were considered as a diagnostic value for schistosomiasis haematobium as well as it correlation between them and intensity of infection by number of ova in urine.


Assuntos
Eosinofilia , Esquistossomose Urinária/diagnóstico , Adolescente , Adulto , Animais , Eosinófilos , Feminino , Humanos , Masculino , Contagem de Ovos de Parasitas , Schistosoma haematobium/isolamento & purificação , Urina/citologia , Urina/parasitologia
12.
Acta Crystallogr C ; 51 ( Pt 9): 1921-3, 1995 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-7576372

RESUMO

The title compound, 2,5-bis(4-methylphenylsulfonyloxy-methyl)oxolane-3,4-diyl diacetate, C24H28O11S2, lies on a crystallographic twofold axis. It adopts a perfect twist 3(4)T conformation in the solid state. The puckering parameters of the tetrahydrofuran ring are q = 0.32 (8) A and rho = 92.3 (5) degrees. The acetyl groups are planar, with the non-H atoms deviating less than 0.002 (3) A from their mean plane. They have an (S)-cis conformation with the C-O and C = O bonds eclipsed, and each acetyl group is orientated with the C = O group syndiaxial to the C-H bond at the ring C atom to which the group is attached.


Assuntos
Hipoglicemiantes/química , Manitol/análogos & derivados , Compostos de Tosil/química , Sítios de Ligação , Cristalização , Cristalografia por Raios X , Espectroscopia de Ressonância Magnética , Manitol/química , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Fosfofrutoquinase-1/química
13.
Carbohydr Res ; 269(2): 191-200, 1995 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-7780989

RESUMO

3,4-Di-O-acetyl-2,5-anhydro-1,6-dideoxy-1,6-diiodo-D-mannitol (3) is prepared from 2,5-anhydro-D-mannitol (1) in three steps. The solution and solid-state NMR spectra of 3 indicate considerable variation in conformation. In solution, it adopts, on average, a symmetric 4T3 conformation, whereas in the solid state it adopts an asymmetric conformation as revealed by 13C NMR cross polarization and magic angle spinning techniques. A single-crystal X-ray structure analysis confirmed the asymmetric conformation of 3 in a monoclinic crystal, space group P2(1) with a = 8.9608(4), b = 8.6348(5), c = 9.6468(4) A, beta = 96.139(4) degrees, V = 742.1(1) A3, Dc = 2.085 g cm-3, mu (MoK alpha) = 4.2 mm-1, and Z = 2. The structure was refined to R = 0.039 and Rw = 0.047 for 5181 observed reflections. The furanoid ring of 3 adopts an envelope E5 conformation slightly distorted towards 4T5, with puckering parameters psi = 313.49 degrees and q = 0.37 A. The asymmetric conformation is rationalized in terms of the weak packing forces in the crystal.


Assuntos
Manitol/análogos & derivados , Cristalografia por Raios X , Espectroscopia de Ressonância Magnética , Manitol/síntese química , Manitol/química , Estrutura Molecular
14.
Carbohydr Res ; 265(2): 197-206, 1994 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-7842442

RESUMO

Complete analyses of the proton and carbon chemical-shift assignments of D-mannurono-gamma-lactone (1) have been achieved by 1D and 2D NMR spectral measurements. At equilibrium, the anomeric alpha and beta forms were present in the ratio of 34:66 in D2O and 72:28 in Me2SO-d6. The solution data indicated that the dienvelope conformation 2E:E4 to be the favored conformation of 1 in solution. The crystal structure of 1 was determined, and it showed that the crystalline form is the beta anomer, a bicyclic structure, consisting of fused five-membered furanose and lactone rings, in agreement with an earlier deduction from chemical evidence. In contrast to the solution conformation, the furanose ring adopts a twist conformation lying between the 2(1)T and 1E conformations with phase angle (P) and pseudorotation amplitude (tau m) of -44.23 degrees and 37.9 degrees, respectively, whereas the lactone ring adopts an envelope E5 conformation slightly distorted towards 6T5 with a phase angle (P) of -22.3 degrees and a pseudorotation amplitude (tau m) of 18.4 degrees. The molecules are linked in the crystal through a hydrogen-bonding network that involves all hydroxyl groups as well as the ring oxygen atoms.


Assuntos
Lactonas/química , Configuração de Carboidratos , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Soluções , Estereoisomerismo
15.
Carbohydr Res ; 265(2): 207-14, 1994 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-7842443

RESUMO

The crystal structure of 3,4,3',4'-tetra-O-acetyl- 6,6'-di(triphenylmethyl)-di-D-fructose anhydride I (1) has been determined by single-crystal X-ray diffraction. The crystals are monoclinic, space group P2(1) with a = 16.399(2), b = 9.091(2), c = 17.946(4) A, beta = 103.66(1) degrees, V = 2600(2) A3, and Z = 2. The structure was refined to R = 0.044 and Rw = 0.051 for 4403 observed reflections. The structure analysis of 1 showed that the previously assigned chemical structure of di-D-fructose anhydride I is undoubtedly alpha-D-fructofuranose beta-D-fructofuranose 1,2':2,1'-dianhydride. The conformations of the furanose rings are E5 with P = 59.8 and tau m = 43.2 degrees for D-fructose 1, and 2T3 with P = -34.39 degrees and tau m = 39.64 degrees for D-fructose 2. The two furanose fragments are linked by a 1,4-dioxane ring in a spiro arrangement. The 1,4-dioxane ring has a chair conformation with Cremer-Pople puckering parameters Q = 0.527 A, phi = 72.2 degrees and the a = 14.2 degrees.


Assuntos
Dioxanos/química , Compostos de Espiro/química , Configuração de Carboidratos , Sequência de Carboidratos , Cristalografia por Raios X , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Molecular
16.
Carbohydr Res ; 264(2): 173-80, 1994 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-7805058

RESUMO

Methyl 2,3,4-tri-O-acetyl-alpha-L-rhamnopyranoside, C13H20O8, M(r) = 304.3, is monoclinic, space group C2, with a = 23.619(1), b = 8.2168(5), c = 19.093(1) A, beta = 118.72(1) degrees, V = 3249.6(8) A3, Dc = 1.244 g cm-3, mu (MoK alpha) = 0.97 cm-1 and Z = 8. The structure was refined to R = 0.044 and Rw = 0.039 for 1969 observed reflections. There are two independent molecules in the asymmetric unit. The bond lengths and bond angles of the pyranose rings of the two are in good agreement within the limits of error. The molecules have similar conformation except for the orientation of one of the acetoxy groups. Each molecule is a normal 1C4 chair with Cremer-Pople puckering parameters Q = 0.557(6) A, theta = 174.6(2) degrees and psi = 144.6(9) degrees for molecule A and 0.564(4) A, 177.9(1) degree and 30.8(8) degrees for molecule B, respectively. The acetyl groups have the planar, (S)-cis conformation most commonly observed. They are oriented with the acetyl planes within +/- 35 degrees of the C-H bond at the ring carbon atom to which they are attached.


Assuntos
Glicosídeos/química , Ramnose/análogos & derivados , Configuração de Carboidratos , Cristalografia por Raios X , Modelos Moleculares , Ramnose/química
17.
Carbohydr Res ; 264(2): 181-90, 1994 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-7805059

RESUMO

The crystal structures of L-rhamnono-1,4-lactone (1) and L-mannono-1,4-lactone (2) have been determined by single-crystal X-ray diffraction. Pertinent crystal data are as follows: for 1, orthorhombic, space group P2(1)2(1)2(1), a = 4.8829(2), b = 10.9088(8), c = 13.9758(9) A, V = 734.7(1) A3, Dc = 1.610 g cm-3, Z = 4, R = 0.028 and Rw = 0.035 for 1586 reflections. The lactone ring of 1 adopts an envelope conformation, E3, slightly distorted toward 2T3, with psi = 103.1(7) degrees and q = 0.38(3) A, whereas the lactone ring of 2 adopts a perfect envelope E3 conformation, with psi = 106.6(4) degrees and q = 0.42(4) A. Molecules of 1 and 2 are linked in their crystals through a three dimensional network of O-H ... H hydrogen-bonding interactions that involves all hydroxyl groups as well as the carbonyl oxygen atom.


Assuntos
4-Butirolactona/análogos & derivados , Lactonas/química , 4-Butirolactona/química , Configuração de Carboidratos , Cristalografia por Raios X/métodos , Ligação de Hidrogênio , Modelos Moleculares
18.
Carbohydr Res ; 264(2): 191-8, 1994 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-7805060

RESUMO

The crystal structure of 2-C-methyl-D-ribo-pentono-1,4-lactone (alpha-D-glucosaccharino-gamma-lactone, 1) has been determined by single-crystal X-ray diffraction. The crystals are orthorhombic, space group P2(1)2(1)2(1) with a = 7.7429(6), b = 8.3373(7), c = 11.3258(7) A, V = 731.1(2) A3 (CuK alpha, lambda = 1.54184 A), mu = 10.82 cm-1, Dc = 1.473 g cm-3, and Z = 4. The structure was refined to R = 0.0307 and Rw = 0.0424 for 876 observed reflections. Compound 1 has the D-ribo configuration, in agreement with an earlier deduction from chemical evidence. The lactone ring adopts the 3T2 conformation, with puckering parameters psi = 279.8(9) degrees and q = 0.32(5) A. The orientation of the methyl group about the C-2-C-3 bond is gauche-trans, with the C-6-C-2-C-3-O-3 and C-6-C-2-C-3-C-4 torsion angles being -81.3(2) degrees and 154.7(1) degree, respectively. The molecules are linked in the crystal in a two-dimensional intermolecular hydrogen bonding network that involves all hydroxyl groups as well as the carbonyl oxygen atom.


Assuntos
4-Butirolactona/análogos & derivados , Lactonas/química , 4-Butirolactona/química , Configuração de Carboidratos , Cristalografia por Raios X/métodos , Ligação de Hidrogênio , Modelos Moleculares
19.
Carbohydr Res ; 261(2): 203-13, 1994 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-7954512

RESUMO

1,2-O-isopropylidene-alpha-D-xylo-pentodialdo-1,4-furanose (1), C16H24O10, M(r) = 376.4, is orthorhombic, space group P2(1)2(1)2(1) with a = 10.3028(10), b = 11.1875(3), c = 15.7484(13) A, V = 1815.2(4) A3, Dc = 1.377 gcm-3, mu(CuK alpha) = 9.5 cm-1 and Z = 4. The structure was refined to R = 0.033 and Rw = 0.045 for 1984 observed reflections. Crystalline 1 has a dimeric cyclic acetal-hemiacetal structure, formed by self aldol condensation of two monomers. The absolute configuration at the condensation centers, C-5 and C-5', were assigned as 5R and 5S, respectively. In the dimer 1, the xylofuranose rings adopt different conformations, one is a twist 3T4, whereas the second is an envelope E4 slightly distorted towards the 3T4 conformation; their fused 1,2-O-isopropylidene rings adopt O-2E and O-2TC-6 conformations, respectively. The 1,3-dioxane ring has a distorted chair conformation with puckering parameters Q = 0.516 A, phi = 90.9, and theta = 11.0 degrees. The molecules are linked in the crystal through intermolecular hydrogen-bonding interactions that involve the two hydroxyl groups, OH-3 and OH-5', and the isopropylidene ring oxygen atoms, O-2 and O-1', as donor and acceptor, respectively.


Assuntos
Dioxanos/química , Dissacarídeos/química , Furanos/química , Cristalização , Cristalografia por Raios X , Ligação de Hidrogênio , Modelos Moleculares , Estrutura Molecular
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