RESUMEN

The zinc oxide nanoparticles (ZnONPs) have attracted exhilarating research interest due to their novel distinguishing characteristics such as size, shape, high surface activity, large surface area and biocompatibility. Being highly bioavailable and exerting a superior efficacy than conventional zinc sources, ZnONPs is emerging as an alternative feed supplement for poultry. The present study involves the synthesis of ZnONPs through a cost effective and eco-friendly method using planetary ball milling technique and characterized for its size, shape, optical property, functional group and elemental concentration using particle size analyzer, Transmission Electron Microscopy, X-Ray Diffraction analysis, Fourier Transform Infra-Red spectroscopy, UV-Vis spectroscopy and Inductively Coupled Plasma-Mass Spectroscopy. In vitro cytotoxicity study using Baby Hamster kidney (BHK-21) cells, Vero cells and primary chick liver culture cells revealed that ZnONPs can be safely incorporated in the broiler chick's feed up to the concentration of 100 mg/kg. To investigate the effects of ZnONPs on production performances in broiler chicks, a feeding trial was carried out using 150-day-old broiler chicks randomly allotted in five treatment groups. The dietary treatment groups were: T1 (80 mg/kg of zinc oxide), T2 (60 mg/kg of zinc methionine) and T3, T4 and T5 received 60, 40 and 20 mg/kg of ZnONPs respectively. The results showed a significant improvement (p < 0.05) in the body weight gain and feed conversion ratio of broiler chicks supplemented with 20 and 40 mg/kg of ZnONPs. The ZnONPs supplementation significantly (p < 0.05) increased the dressing percentage in addition to significant (p < 0.05) reduction in the meat pH compared to inorganic and organic zinc supplementation. Overall, an eco-friendly method for ZnONPs synthesis was demonstrated and the optimum dietary level (20 mg/kg) of ZnONPs could enhance the growth, the meat quality and Zn uptake without any negative effects on selected serum biochemical parameters in the broiler chicks.

Asunto(s)

Nanopartículas del Metal , Óxido de Zinc , Chlorocebus aethiops , Animales , Óxido de Zinc/farmacología , Óxido de Zinc/química , Pollos/metabolismo , Células Vero , Suplementos Dietéticos/análisis , Zinc/farmacología , Nanopartículas del Metal/química , Carne/análisis , Alimentación Animal/análisis

RESUMEN

OBJECTIVE: Nocardia kroppenstedtii was isolated from the spinal vertebral abscess of a 78-year-old patient presenting with mid-thoracic pain and bilateral lower limb weakness and numbness. The patient was on long-term immunosuppressive therapy with steroids for underlying autoimmune hemolytic anemia. Investigations showed a T5 pathological fracture and vertebra plana with the erosion of the superior and inferior endplates. There was evidence of paraspinal collection from the T4-T6 vertebrae with an extension into the spinal canal. Analysis of Nocardia 16S rRNA (99.9%, 1395/1396 nt) and secA1 gene (99.5%, 429/431 nt) fragments showed the highest sequence similarity with Nocardia kroppenstedtii type strain (DQ157924), and next with Nocardia farcinica (Z36936). The patient was treated with intravenous carbapenem and oral trimethoprim-sulfamethoxazole for four weeks, followed by another six months of oral trimethoprim-sulfamethoxazole. Despite the improvement of neurological deficits, the patient required assistive devices to ambulate at discharge. This study reports the first isolation of N. kroppenstedtii from the spinal vertebral abscess of a patient from Asia. Infections caused by N. kroppenstedtii may be underdiagnosed as the bacterium can be misidentified as N. farcinica in the absence of molecular tests in the clinical laboratory.

Asunto(s)

Absceso Epidural/microbiología , Nocardiosis/microbiología , Nocardia/aislamiento & purificación , Administración Oral , Anciano , Anemia Hemolítica Autoinmune/tratamiento farmacológico , Anemia Hemolítica Autoinmune/microbiología , Antibacterianos/administración & dosificación , Antibacterianos/farmacología , Absceso Epidural/tratamiento farmacológico , Femenino , Humanos , Inmunosupresores/uso terapéutico , Nocardia/efectos de los fármacos , Nocardiosis/tratamiento farmacológico , Esteroides/uso terapéutico , Sulfametoxazol/administración & dosificación , Sulfametoxazol/farmacología , Trimetoprim/administración & dosificación , Trimetoprim/farmacología

RESUMEN

BACKGROUND: Chronic Kidney Disease of unknown etiology (CKDu) is prevalent in North Central Province (NCP) of Sri Lanka. Consumption of un-boiled dug well water has been identified as one of the causative factors. This in-vivo study was performed to investigate some of the suspected factors associated with the pathogenesis of CKDu mediated via ground water. METHOD: Rats were given water, collected from high and low disease prevalent areas from the NCP of Sri Lanka and the results compared with those obtained from previously identified low disease prevalent area; Colombo. Blood Urea Nitrogen, creatinine, urinary microalbumin:creatinine ratio together with ALT and AST levels were analyzed and results were compared using one-way ANOVA and paired t-Test. Histopathology was analyzed using non-parametric method. RESULTS: Rats that ingested water from New Town Medirigiriya (NTM) from high disease prevalent NCP reported significantly elevated microalbumin:creatinine ratios compared to other water sources after 8 months, whilst boiled water from NTM had been able to significantly reduce it. Histopathological findings after the 14 months experimental period revealed significantly high tubular lesion index in rats that ingested water from NCP compared to Colombo. Rats that ingested water from high disease prevalent Divuldamana (DD) from NCP showed the highest kidney lesion index though the fluoride content was relatively low in this area compared to other water sources from high disease prevalent NCP. Rats that ingested boiled and un-boiled water from NTM also developed severe lesions whilst the group from Colombo reported the lowest. Low disease prevalent area from NCP, Huruluwewa (HW) also reported elevated liver enzymes and altered renal histopathology. Association of Na+:Ca2+ ratio in the disease progression was not reflected by the current study. Compared to Colombo, high fluoride, calcium and sodium contents were observed in water from high disease prevalent areas. All the water samples were negative for heavy metals. CONCLUSIONS: Though Fluoride is a known kidney toxic agent it cannot be the sole reason for CKDu in NCP, Sri Lanka. Various toxic elements present in NCP water may contribute to different grade of kidney and liver lesions in Wistar rats.

Asunto(s)

Agua Potable/efectos adversos , Agua Potable/química , Agua Subterránea/química , Insuficiencia Renal Crónica/etiología , Alanina Transaminasa/sangre , Albuminuria/orina , Animales , Aspartato Aminotransferasas/sangre , Nitrógeno de la Urea Sanguínea , Calcio/análisis , Creatinina/sangre , Creatinina/orina , Agua Potable/administración & dosificación , Femenino , Fluoruros/análisis , Hepatitis/sangre , Hepatitis/etiología , Hepatitis/patología , Túbulos Renales/patología , Masculino , Distribución Aleatoria , Ratas , Ratas Wistar , Insuficiencia Renal Crónica/sangre , Insuficiencia Renal Crónica/patología , Insuficiencia Renal Crónica/orina , Sodio/análisis , Sri Lanka

RESUMEN

Two common classes of nitrogen-fixing legume root nodules are those that have determinate or indeterminate meristems, as in Phaseolus bean and pea, respectively. In indeterminate nodules, rhizobia terminally differentiate into bacteroids with endoreduplicated genomes, whereas bacteroids from determinate nodules are less differentiated and can regrow. We used RNA sequencing to compare bacteroid gene expression in determinate and indeterminate nodules using two Rhizobium leguminosarum strains whose genomes differ due to replacement of the symbiosis (Sym) plasmid pRP2 (strain Rlp4292) with pRL1 (strain RlvA34), thereby switching symbiosis hosts from Phaseolus bean (determinate nodules) to pea (indeterminate nodules). Both bacteroid types have gene expression patterns typical of a stringent response, a stressful environment and catabolism of dicarboxylates, formate, amino acids and quaternary amines. Gene expression patterns were indicative that bean bacteroids were more limited for phosphate, sulphate and iron than pea bacteroids. Bean bacteroids had higher levels of expression of genes whose products are predicted to be associated with metabolite detoxification or export. Pea bacteroids had increased expression of genes associated with DNA replication, membrane synthesis and the TCA (tricarboxylic acid) cycle. Analysis of bacteroid-specific transporter genes was indicative of distinct differences in sugars and other compounds in the two nodule environments. Cell division genes were down-regulated in pea but not bean bacteroids, while DNA synthesis was increased in pea bacteroids. This is consistent with endoreduplication of pea bacteroids and their failure to regrow once nodules senesce.

Asunto(s)

Regulación Bacteriana de la Expresión Génica , Phaseolus/microbiología , Pisum sativum/microbiología , Rhizobium leguminosarum/genética , Nódulos de las Raíces de las Plantas/microbiología , ADN Bacteriano/genética , Perfilación de la Expresión Génica , Plásmidos , Metabolismo Secundario/genética , Simbiosis

RESUMEN

In the title compound, C30H31N3O2S, the fused pyrrolidine ring bearing three substituents adopts an envelope conformation with the C atom bearing the benzoyl group as the flap. The other fused pyrrolidine ring adopts a twisted conformation about one of its C-C bonds. The dihedral angle between the isatin ring system and the methyl-thia-zole ring is 25.95 (8)°. An intra-molecular C-H⋯O inter-action closes an S(8) ring. In the crystal, mol-ecules are linked by C-H⋯O inter-actions, generating C(11) chains propagating in [001].

RESUMEN

There are two independent mol-ecules in the asymmetric unit of the title compound, C19H16N2O5S, in which the thia-zole rings make dihedral angles of 80.89 (11) and 84.81 (11)° with the pyrano[3,2-c]chromene ring systems. An intra-molecular N-H⋯O hydrogen bond involving the amino group occurs in each independent mol-ecule. In the crystal, the amino groups are involved in N-H⋯O and N-H⋯N hydrogen bonds.

RESUMEN

In the title compound, C(19)H(14)OS, the naphtho-thio-phene moiety is almost planar except for the S atom of the five-membered ring, which is situated 0.047 (6) Šout of the C(4) plane (with an r.m.s. deviation of fitted atoms = 0.0009 Å). The dihedral angle between the naphtho-thio-phene plane and the attached meth-oxy-phenyl ring is 67.6 (2)°. In the crystal, a C-H⋯π inter-action is observed between a meth-oxy-phenyl C-H group and the outer benzene ring of the naphtho-thio-phene moiety. The five-membered ring of the naphtho-thio-phene moiety is disordered, with the S and opposite non-fused C atom approximately exchanging positions, with a site-occupancy factors of 0.808 (3) and 0.187 (3).

RESUMEN

Mutation of ptsP encoding EI(Ntr) of the PTS(Ntr) system in Rhizobium leguminosarum strain Rlv3841 caused a pleiotropic phenotype as observed with many bacteria. The mutant formed dry colonies and grew poorly on organic nitrogen or dicarboxylates. Most strikingly the ptsP mutant had low activity of a broad range of ATP-dependent ABC transporters. This lack of activation, which occurred post-translationally, may explain many of the pleiotropic effects. In contrast proton-coupled transport systems were not inhibited in a ptsP mutant. Regulation by PtsP also involves two copies of ptsN that code for EIIA(Ntr) , resulting in a phosphorylation cascade. As in Escherichia coli, the Rlv3841 PTS(Ntr) system also regulates K(+) homeostasis by transcriptional activation of the high-affinity ATP-dependent K(+) transporter KdpABC. This involves direct interaction of a two-component sensor regulator pair KdpDE with unphosphorylated EIIA(Ntr) . Critically, ptsP mutants, which cannot phosphorylate PtsN1 or PtsN2, had a fully activated KdpABC transporter. This is the opposite pattern from that observed with ABC transporters which apparently require phosphorylation of PtsN. These results suggest that ATP-dependent transport might be regulated via PTS(Ntr) responding to the cellular energy charge. ABC transport may be inactivated at low energy charge, conserving ATP for essential processes including K(+) homeostasis.

Asunto(s)

Transportadoras de Casetes de Unión a ATP/metabolismo , Proteínas Bacterianas/metabolismo , Sistema de Fosfotransferasa de Azúcar del Fosfoenolpiruvato/metabolismo , Potasio/metabolismo , Rhizobium leguminosarum/genética , Transportadoras de Casetes de Unión a ATP/genética , Proteínas Bacterianas/genética , Transporte Biológico , Regulación Bacteriana de la Expresión Génica , Homeostasis , Mutación , Sistema de Fosfotransferasa de Azúcar del Fosfoenolpiruvato/genética , Fosforilación , Proteínas Quinasas/metabolismo , Rhizobium leguminosarum/crecimiento & desarrollo , Rhizobium leguminosarum/metabolismo , Activación Transcripcional

RESUMEN

BACKGROUND: Brucella species are easily transmitted by aerosols and can be acquired in the laboratory. AIM: To report the management of a large exposure to Brucella melitensis that occurred over six days in a hospital diagnostic laboratory. METHODS: Fifty-one exposed staff were managed according to Centers for Disease Control and Prevention guidelines. A further 96 non-exposed laboratory staff were tested for seroprevalence. Testing was carried out using the Brucella sp. serum agglutination test. FINDINGS: Twenty-seven people had high-risk exposure and 24 had low-risk exposure. High-risk staff were offered post-exposure prophylaxis. Twelve (44.4%) agreed to this, of whom eight (66.7%) completed the course. Overall compliance with serological follow-up at baseline, 2, 4, 6 weeks and 8 months was 45.9%. Despite this poor compliance there were no clinical brucellosis cases and no seroconversion in the 47.1% of staff tested at 8 months. Brucella sp. seroprevalence among all staff tested was 3/147 (2.0%). CONCLUSION: Lack of experience with Brucella spp. and lack of policies for handling potentially hazardous organisms contributed to this prolonged exposure. As compliance with current recommendations may be poor, the optimum frequency of serological follow-up and target groups for prophylaxis should be reassessed. Laboratories in low- or non-endemic areas must prepare for potential isolation of Brucella spp. The impact of human brucellosis in Malaysia requires further study.

Asunto(s)

Brucella melitensis/aislamiento & purificación , Brucelosis/prevención & control , Laboratorios de Hospital , Exposición Profesional , Adolescente , Anticuerpos Antibacterianos/sangre , Actitud del Personal de Salud , Femenino , Humanos , Malasia , Profilaxis Posexposición/métodos

RESUMEN

In the title compound, C(27)H(19)NO(2)S, the naphtho-carbazole unit is approximately planar (r.m.s. deviation = 0.002 Å) except for the N atom, which is displaced by 0.122 (1) Šout of the mean plane. The dihedral angle between the naphtho-carbazole mean plane and the phenyl ring of the phenyl-sulfonyl substituent is 83.16 (3)°. An inter-molecular C-H⋯π inter-action involving the phenyl group and the pyrrole ring is observed in the crystal structure.

RESUMEN

Tsukamurella spp. are a rare but important cause of intravascular catheter-related bacteremia in immunocompromised patients. The organism is an aerobic, Gram-positive, weakly acid-fast bacillus that is difficult to differentiate using standard laboratory methods from other aerobic actinomycetales such as Nocardia spp., Rhododoccus spp., Gordonia spp., and the rapid growing Mycobacterium spp. We report a case of Tsukamurella tyrosinosolvens catheter-related bacteremia in a 51-year-old haematology patient who responded to treatment with imipenem and subsequent line removal. 16srRNA sequencing allowed for the prompt identification of this organism.

Asunto(s)

Infecciones por Actinomycetales/microbiología , Bacteriemia/microbiología , Infecciones Relacionadas con Catéteres/microbiología , Actinomycetales/genética , Infecciones por Actinomycetales/tratamiento farmacológico , Antibacterianos/uso terapéutico , Infecciones Relacionadas con Catéteres/tratamiento farmacológico , Cateterismo Venoso Central , Femenino , Humanos , Imipenem/uso terapéutico , Leucemia Mieloide Aguda/complicaciones , Leucemia Mieloide Aguda/tratamiento farmacológico , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Persona de Mediana Edad , ARN Bacteriano/análisis , ARN Ribosómico 16S/análisis

RESUMEN

OBJECTIVES: Acute appendicitis is a common surgical emergency. The etiology and pathophysiology of appendicitis have been well investigated. Aggregatibacter aphrophilus is a fastidious gram-negative coccobacilli. Detection of this organism in clinical samples and its differentiation from Haemophilus aphrophilus or from Aggregatibacter actinomycetemcomitans in routine microbiology settings could be difficult. METHODS: In this rare case, we report the isolation of Aggregatibacter aphrophilus from the appendix of a 14-year-old boy presented with acute appendicitis. The genotypic method using 16S rRNA sequencing was used for identification of the organism at species level. CONCLUSION: This case highlights the importance of detecting fastidious and rare microorganisms such as Aggregatibacter aphrophilus that could be associated with acute appendicitis.

Asunto(s)

Apendicitis/microbiología , Apéndice/microbiología , Haemophilus paraphrophilus/aislamiento & purificación , Enfermedad Aguda , Adolescente , Apendicectomía , Apendicitis/cirugía , Apéndice/cirugía , ADN Bacteriano/aislamiento & purificación , Haemophilus paraphrophilus/clasificación , Haemophilus paraphrophilus/genética , Humanos , Masculino , ARN Ribosómico 16S/genética , Ribotipificación

RESUMEN

Mutation of gltB (encoding glutamate oxoglutarate amidotransferase or GOGAT) in RU2307 increased the intracellular Gln:Glu ratio and inhibited amino acid transport via Aap and Bra. The mechanism probably involves global post-translational inhibition independent of Ntr. Transport was separately restored by increased gene expression of Aap or heterologous transporters. Likewise, second site suppressor mutations in the RNA chaperone Hfq elevated transport by Aap and Bra by increasing mRNA levels. Microarrays showed Hfq regulates 34 ABC transporter genes, including aap, bra and opp. The genes coding for integral membrane proteins and ABC subunits aapQMP braDEFGC were more strongly elevated in the hfq mutants than solute-binding proteins (aapJ braC). aapQMP and braDEFG are immediately downstream of stem-loops, indicating Hfq attenuates downstream translation and stability of mRNA, explaining differential expression of ABC genes. RU2307 nodulated peas and bacteria grew down infection threads, but bacteroid development was arrested and N(2) was not fixed. This probably results from an inability to synthesize or transport amino acids. However, GOGAT and GOGAT/AldA double mutants carrying suppressor mutations that increased amino acid uptake fixed N(2) on pea plants. Thus de novo ammonium assimilation into amino acids is unnecessary in bacteroids demonstrating sufficient amino acids are supplied by plants.

Asunto(s)

Proteínas Bacterianas/metabolismo , Fijación del Nitrógeno/fisiología , Nitrógeno/metabolismo , Pisum sativum/microbiología , Rhizobium leguminosarum/metabolismo , Rhizobium leguminosarum/fisiología , Proteínas Bacterianas/genética , Cromatografía Liquida , Espectrometría de Masas , Mutación , Fijación del Nitrógeno/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rhizobium leguminosarum/genética

RESUMEN

Group B streptococcus (GBS) is a leading cause of neonatal sepsis and is usually acquired via the woman's birth canal. GBS serotypes isolated from 200 pregnant women were determined. Serotypes V (19%) and VI (17%) were the most frequent followed by serotypes III (12%), Ia (11.5%) and IV (10%); 17% of the strains were non-typable. All isolates were susceptible to penicillin, 96% to erythromycin and 97.5% to clindamycin. The emergence of new GBS serotypes has important implications for vaccine prevention strategies.

Asunto(s)

Antibacterianos/farmacología , Streptococcus agalactiae/clasificación , Streptococcus agalactiae/efectos de los fármacos , Farmacorresistencia Bacteriana , Femenino , Humanos , Malasia/epidemiología , Embarazo , Serotipificación

RESUMEN

Rhizobium leguminosarum bv. viciae forms nitrogen-fixing nodules on several legumes, including pea (Pisum sativum) and vetch (Vicia cracca), and has been widely used as a model to study nodule biochemistry. To understand the complex biochemical and developmental changes undergone by R. leguminosarum bv. viciae during bacteroid development, microarray experiments were first performed with cultured bacteria grown on a variety of carbon substrates (glucose, pyruvate, succinate, inositol, acetate, and acetoacetate) and then compared to bacteroids. Bacteroid metabolism is essentially that of dicarboxylate-grown cells (i.e., induction of dicarboxylate transport, gluconeogenesis and alanine synthesis, and repression of sugar utilization). The decarboxylating arm of the tricarboxylic acid cycle is highly induced, as is gamma-aminobutyrate metabolism, particularly in bacteroids from early (7-day) nodules. To investigate bacteroid development, gene expression in bacteroids was analyzed at 7, 15, and 21 days postinoculation of peas. This revealed that bacterial rRNA isolated from pea, but not vetch, is extensively processed in mature bacteroids. In early development (7 days), there were large changes in the expression of regulators, exported and cell surface molecules, multidrug exporters, and heat and cold shock proteins. fix genes were induced early but continued to increase in mature bacteroids, while nif genes were induced strongly in older bacteroids. Mutation of 37 genes that were strongly upregulated in mature bacteroids revealed that none were essential for nitrogen fixation. However, screening of 3,072 mini-Tn5 mutants on peas revealed previously uncharacterized genes essential for nitrogen fixation. These encoded a potential magnesium transporter, an AAA domain protein, and proteins involved in cytochrome synthesis.

Asunto(s)

Pisum sativum/microbiología , Rhizobium leguminosarum/genética , Simbiosis , Transcripción Genética , Vicia/microbiología , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica , Pisum sativum/fisiología , Rhizobium leguminosarum/crecimiento & desarrollo , Rhizobium leguminosarum/fisiología , Nódulos de las Raíces de las Plantas/microbiología , Nódulos de las Raíces de las Plantas/fisiología , Especificidad de la Especie , Vicia/fisiología

RESUMEN

Anabaena PCC 7120 nifHDK operon is interrupted by an 11 kb DNA element which is excised during the development of heterocysts by Excisase A, encoded by the xisA gene residing on the element. The excision is a site-specific recombination event that occurs at the 11 base pair direct repeats flanking the element. Earlier work showed the excision of the 11 kb element in Escherichia coli at a frequency 0.3%. We report here the excision of this element at 1.1% and 1.98% in E. coli DH5alpha, and 1.9% and 10.9% in E. coli JM 101 when grown on Luria broth and minimal media, respectively. Excision of nifD element in isogenic recA(-) (RK1) and recA+ (RK2) E. coli JM101 P1 transductants, showed similar results to that of E. coli JM101 and DH5alpha, respectively. A plasmid pMX32, carrying a xisA defective 11kb element, showed no excision in E. coli RK2 strain. In contrast to Anabaena PCC 7120, excision of nifD element did not increase in E. coli DH5alpha grown in iron-deficient conditions. A PxisA::lacZ transcriptional fusion, used to detect the expression of elusive xisA gene, showed maximal beta-galactosidase activity in the stationary phase. The results suggest that the excision event in E. coli may involve additional factors, such as RecA and that the physiological status can influence the excision of nifD element.

Asunto(s)

Anabaena/genética , Proteínas Bacterianas/genética , Escherichia coli/crecimiento & desarrollo , Regulación Bacteriana de la Expresión Génica , Reordenamiento Génico , Genes Bacterianos , Rec A Recombinasas/metabolismo , Anabaena/efectos de los fármacos , Medios de Cultivo , Enzimas de Restricción del ADN/metabolismo , ADN Bacteriano/genética , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Hierro/farmacología , Cinética , Nitrógeno/farmacología , Plásmidos/genética , Reacción en Cadena de la Polimerasa , Eliminación de Secuencia

RESUMEN

The ethanol and methanol extracts of Cassia auriculata flowers were screened for antioxidant activity. The antioxidant activity was determined by an improved assay based on the decolorization of the radical monocation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. The ethanol and methanol extracts of C. auriculata flowers showed antioxidant activity in both assays.

Asunto(s)

Antioxidantes/farmacología , Cassia , Fitoterapia , Extractos Vegetales/farmacología , Antioxidantes/administración & dosificación , Antioxidantes/uso terapéutico , Benzotiazoles/química , Compuestos de Bifenilo , Flores , Humanos , Concentración 50 Inhibidora , Picratos/química , Extractos Vegetales/administración & dosificación , Extractos Vegetales/uso terapéutico , Ácidos Sulfónicos/química

RESUMEN

In the absence of added thiamine, Rhizobium leguminosarum bv. viciae strain 3841 does not grow in liquid medium and forms only "pin" colonies on agar plates, which contrasts with the good growth of Sinorhizobium meliloti 1021, Mesorhizobium loti 303099, and Rhizobium etli CFN42. These last three organisms have thiCOGE genes, which are essential for de novo thiamine synthesis. While R. leguminosarum bv. viciae 3841 lacks thiCOGE, it does have thiMED. Mutation of thiM prevented formation of pin colonies on agar plates lacking added thiamine, suggesting thiamine intermediates are normally present. The putative functions of ThiM, ThiE, and ThiD are 4-methyl-5-(beta-hydroxyethyl) thiazole (THZ) kinase, thiamine phosphate pyrophosphorylase, and 4-amino-5-hydroxymethyl-2-methyl pyrimidine (HMP) kinase, respectively. This suggests that a salvage pathway operates in R. leguminosarum, and addition of HMP and THZ enabled growth at the same rate as that enabled by thiamine in strain 3841 but elicited no growth in the thiM mutant (RU2459). There is a putative thi box sequence immediately upstream of the thiM, and a gfp-mut3.1 fusion to it revealed the presence of a promoter that is strongly repressed by thiamine. Using fluorescent microscopy and quantitative reverse transcription-PCR, it was shown that thiM is expressed in the rhizosphere of vetch and pea plants, indicating limitation for thiamine. Pea plants infected by RU2459 were not impaired in nodulation or nitrogen fixation. However, colonization of the pea rhizosphere by the thiM mutant was impaired relative to that of the wild type. Overall, the results show that a thiamine salvage pathway operates to enable growth of Rhizobium leguminosarum in the rhizosphere, allowing its survival when thiamine is limiting.

Asunto(s)

Rhizobium leguminosarum/genética , Rhizobium leguminosarum/metabolismo , Tiamina/biosíntesis , Transferasas Alquil y Aril/fisiología , Fusión Artificial Génica , Sitios de Unión , Recuento de Colonia Microbiana , Eliminación de Gen , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Proteínas Fluorescentes Verdes/biosíntesis , Proteínas Fluorescentes Verdes/genética , Microscopía Fluorescente , Fijación del Nitrógeno , Pisum sativum/microbiología , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Fosfotransferasas (Aceptor del Grupo Fosfato)/metabolismo , Raíces de Plantas/microbiología , Regiones Promotoras Genéticas , Pirimidinas/metabolismo , ARN Bacteriano/análisis , ARN Mensajero/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rhizobium leguminosarum/crecimiento & desarrollo , Tiazoles/metabolismo , Vicia/microbiología

RESUMEN

Rhodococcus equi, a recognized pathogen in horses, is emerging as a human opportunistic pathogen, especially in immunocompromized hosts. We describe four immunocompromized patients who had serious R. equi infections with an overall mortality of 75%. The natural habitat of R. equi is soil, particularly soil contaminated with animal manure. Necrotizing pneumonia is the commonest form of infection but extrapulmonary infections, such as wound infections and subcutaneous abscess, have also been described in humans. R. equi is cultured easily in ordinary non-selective media. Large, smooth, irregular colonies appear within 48 hours. It is a facultative, intracellular, nonmotile, non-spore forming, gram-positive coccobacillus, which is weakly acid-fast staining and bears a similarity to diphtheroids. It forms a salmon-colored pigment usually after 48 hours incubation. A particular characteristic of this organism is that it undergoes synergistic hemolysis with some bacteria on sheep blood agar. R. equi may be misidentified as diphtheroids, Mycobacterium species, or Nocardia. In vitro R. equi is usually susceptible to erythromycin, ciprofloxacin, vancomycin, aminoglycosides, rifampin, imipenem and meropenem. The organism can be difficult to eradicate, making treatment challenging. Increased awareness of the infection may help with early diagnosis and timely treatment.

Asunto(s)

Infecciones por Actinomycetales/diagnóstico , Huésped Inmunocomprometido , Infecciones Oportunistas/diagnóstico , Rhodococcus equi , Infecciones por Actinomycetales/tratamiento farmacológico , Infecciones por Actinomycetales/microbiología , Adolescente , Adulto , Antibacterianos/uso terapéutico , Resultado Fatal , Femenino , Humanos , Malasia , Masculino , Persona de Mediana Edad , Infecciones Oportunistas/tratamiento farmacológico , Infecciones Oportunistas/microbiología

RESUMEN

An activity-directed fractionation and purification process was used to identify the nitric oxide (NO) scavenging components of Phyllanthus emblica. Dried fruit rind of P. emblica was extracted with methanol and then separated into hexane, ethyl acetate, and water fractions. Among these only the ethyl acetate phase showed strong NO scavenging activity in vitro, when compared with water and hexane phases. The ethyl acetate fraction was then subjected to separation and purification using Sephadex LH-20 chromatography. Five compounds showing strong NO scavenging activity were identified by spectral methods (1H NMR, 13C NMR, and MS) and by comparison with literature values to be Gallic acid, Methyl gallate, Corilagin, Furosin, and Geraniin. In addition, HPLC identification and quantification of isolated compounds were also performed. Gallic acid was found to be a major compound in the ethyl acetate extract and Geraniin showed highest NO scavenging activity among the isolated compounds.

Asunto(s)

Antioxidantes/aislamiento & purificación , Depuradores de Radicales Libres/aislamiento & purificación , Ácido Gálico/aislamiento & purificación , Óxido Nítrico/aislamiento & purificación , Phyllanthus emblica/química , Antioxidantes/química , Cromatografía Líquida de Alta Presión , Depuradores de Radicales Libres/metabolismo , Radicales Libres , Ácido Gálico/metabolismo , Espectroscopía de Resonancia Magnética , Óxido Nítrico/metabolismo , Extractos Vegetales/química