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Hypermucoviscosity in Clinical Isolates of Klebsiella pneumoniae Correlates with High Multiple Antibiotic Resistance (MAR) Index

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Open Journal of Medical Microbiology 2016年第3期6卷 97-103页

作者： uzal umar Sandra Anagor Abdullahi Aliyu Abdulmumini Ibrahim Suleiman Department of Biological Sciences Abubakar Tafawa Balewa University Bauchi Nigeria Department of Clinical Microbiology Abubakar Tafawa Balewa University Teaching Hospital Bauchi Nigeria

Klebsiella pneumoniae is an opportunistic pathogen of medical importance and the capsule and mucoid phenotype in this organism are considered as requisite virulence determinants. A total of 62 clinical samples from ATBUTH were collected and screened for K. pneumoniae. The isolates were identified using standard tests for this organism. The string test was used to detect the mucoid (hypermucoviscous) phenotype and the antimicrobial susceptibility test to 10 antibiotics was carried out with the disk diffusion technique after standardizing inoculum. A K. pneumoniae prevalence of 24% (15/62) was obtained of which 47% (7/15) were mucoid (hypermucoviscous) and 53% (8/15) were non-mucoid. Colonial sizes of the two strains do not reveal any significant differences in growth fitness of the strains. On blood agar, the mucoid and non-mucoid strains had a mean colonial size ± standard deviations of 4.41 ± 0.58 mm and 4.27 ± 0.42 mm respectively. The antibiotic susceptibility rate showed that the mucoid strains compared to the non-mucoid were more resistant to nine out of 10 antibiotics. The mucoid strains were outrightly resistant to augmentin, amoxicillin, septrin, sparfloxacin and perfloxacin. The non-mucoid strains showed no complete resistant to any antibiotic tested but had a higher resistant rate to chloramphenicol only. The Multiple Antibiotic Resistance (MAR) index shows the themucoid strains with a high MAR index range of 0.7 - 1.0 with a median MAR index of 0.8, while the non-mucoid strains had a MAR index of 0.2 - 0.8 with a median MAR index of 0.35. The data suggest that the mucoid phenotype could be associated with extrachromsomal element(s) carrying resistance genes to antibiotics and that these extrachromosomal elements may not harbour resistance determinants to chloramphenicol. Furthermore, the extrachromosomal elements bearing the mucoid phenotype and the resistance elements in the mucoid strains do not significantly impact on the fitness of the cognate strain.

关键词： Hypermucoviscousity PLA Phagocytosis Siderophores Virulence

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Clinical Isolates of Staphylococcus aureus Show Variation in β-Lactamase Production and Are More Susceptible to Antibiotics Conjugated with β-Lactamase Inhibitors

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Open Journal of Medical Microbiology 2016年第4期6卷 143-149页

作者： uzal umar umar Ahmed Faruk Damoroem M. Tanko Mohammed B. Yerima Department for Biological Sciences Abubakar Tafawa Balewa University Bauchi Nigeria Department of Microbiology Federal University Dutse Dutse Nigeria

β-Lactam antibiotics are a cornerstone in the treatment of bacterial infections on account of its high therapeutic index and selective toxicity—they act by inhibiting the biosynthesis of peptidoglycan, a key component in bacterial cell wall. Ninety (90) clinical specimens obtained from the microbiology unit Specialist Hospital Bauchi were screened for S. aureus, positive isolates were examined for β-Lactamase expression by using two Penicillin G concentrations (5000 IU/ml and 25,000 IU/ml) in acidometric agar technique with phenol red as indicator, and the susceptibility pattern of the isolates to β-Lactam antibiotics was also determined. S. aureus prevalence of 31% (28/90) was obtained, of which 96% (27/28) of strains were β-Lactamase positive in the standard test, while 63% (17/27) were able to hydrolyze penicillin G concentration of 25,000 IU/ml (5X the concentration in the standard test), and a strain was found to be β-Lactamase negative. The resistance to five β-Lactams, ampicillin, cephalexin, amoxicillin, cloxacillin and flucloxaillin, were 100%, 96%, 89%, 74% and 56% respectively. When ampicillin and amoxicillin were conjugated to β-Lactamase inhibitors sulbactam and clavulanic acid respectively the resistance to ampicillin decreased to 21% and to amoxicillin to 15%. The antibiotic susceptibility profile revealed β-Lactamase elaboration to be the major mechanism of resistance to the β-Lactams. β-Lactam utilization as therapeutic option would thus require the search for sensitive irreversible β-Lactamase inhibitors for the β-Lactamase enzymes or agents to block the release of β-Lactamase by strains.

关键词： β-Lactamase Peptidoglycan Transpeptidation Haemolysis Resistance Antibiotics

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More Transporters,More Substrates:The Arabidopsis Major Facilitator Superfamily Revisited

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Molecular Plant 2019年第9期12卷 1182-1202页

作者： Maria Nino-Gonzalez Esther Novo-uzal Dale N.Richardson Pedro M.Barros Paula Duque Instituto Gulbenkian de Ciencia 2780-156 OeirasPortugal Genomics of Plant Stress Unit ITQB NOVA-Instituto de Tecnologia Quimica e Biologica Antonio XavierUniversidade Nova de Lisboa2780-157 OeirasPortugal

The Major Facilitator Superfamily(MFS)is ubiquitous in living organisms and represents the largest group of secondary active membrane *** plants,significant research efforts have focused on the role of specific families within the MFS,particularly those transporting macronutrients(C,N,and P)that constitute the vast majority of the members of this *** MFS families remain less explored,although a plethora of additional substrates and physiological functions have been ***,the lack of a systematic approach to analyzing the MFS as a whole has obscured the high diversity and versatility of these ***,we present a phylogenetic analysis of all annotated MFS domaincontaining proteins encoded in the Arab/dops/s fA?a//ana genome and propose that this superfamily of transporters consists of 218 members,clustered in 22 *** reviewing the available information regarding the diversity in biological functions and substrates of Arab/dops/s MFS members,we provide arguments for intensified research on these membrane transporters to unveil the breadth of their physiological relevance,disclose the molecular mechanisms underlying their mode of action,and explore their biotechnological potential.

关键词： Arabidopsis thaliana membrane transport MFS transporters phylogenetic analysis

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Downregulation of the Basic Peroxidase Isoenzyme from Zinnia elegans by Gibberellic Acid

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Journal of Integrative Plant Biology 2010年第2期52卷 244-251页

作者： María Josefa López Núez-Flores Jorge Gutirrez Laura V.Gómez-Ros Esther Novo uzal Mariana Sottomayor Alfonso Ros Barceló Department of Plant Biology University of MurciaE-30100MurciaSpain Department of Plant Biology University of La CoruaE-15071La CorunaSpain IBMC University of Porto4150 PortoPortugal

Hypocotyl formation during the epigeal germination of seedlings is under strict hormonal regulation. In a 3 d old Zinnia elegans seedling system, gibberellic acid （GA3） exerts an opposite effect to that exerted by light on hypocotyl photomorphogenesis because GAz promotes an etiolated-like growth with an inhibition of radial （secondary） growth. For this reason, the effect of GA3 on the basic peroxidase isoenzyme from Z. elegans （ZePrx）, an enzyme involved in hypocotyl lignin biosynthesis, was studied. The results showed that GA3 reduces ZePrx activity, similarly to the way in which it reduces seedling secondary growth. This hormonal response is supported by the analysis of the ZePrx promoter, which contains four types of GA3-responsive ***： the W Box/O2S; the Pyr Box; the GARE; and the Amy Box. Taken together, these results suggest that ZePrx is directly regulated by GA3, with this effect matching the inhibitory effect of GA on the hypocotyl secondary growth.

关键词： GA Downregulation of the Basic Peroxidase Isoenzyme from Zinnia elegans by Gibberellic Acid cis Figure

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Ectopic lignification in primary cellulose-deficient cell walls of maize cell suspension cultures

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Journal of Integrative Plant Biology 2015年第4期57卷 357-372页

作者： Hugo Mélida Asier Largo-Gosens Esther Novo-uzal Rogelio Santiago Federico Pomar Pedro García Penélope García-Angulo José Luis Acebes Jesús álvarez Antonio Encina Plant Physiology Laboratory Faculty of Biological and Environmental SciencesUniversity of León Centre for Plant Biotechnology and Genomics (CBGP) Politechnical University of Madrid Department of Plant Biology University of Murcia Plant Biology and Soil Sciences Department Faculty of BiologyUniversity of Vigo Environmental Agrobiology Soil and Plant Quality (University of Vigo)Associated Unit to Biological Mission of Galicia (CSIC) Department of Animal Biology Plant Biology and EcologyUniversity of A Coru?a Department of Molecular Biology(área de Genética) Faculty of Biological and Environmental SciencesUniversity of León

Maize （Zea mays L.） suspension-cultured cells with up to 7o% less cellulose were obtained by stepwise habituation to dichlobenil （DCB）, a cellulose biosynthesis inhibitor. Cellulose deficiency was accompanied by marked changes in cell wall matrix polysaccharides and phenolics as revealed by Fourier transform infrared （FTIR） spectroscopy. Cell wall compositional analysis indicated that the cellulosedeficient cell walls showed an enhancement of highly branched and cross-linked arabinoxylans, as well as an increased content in ferulic acid, diferulates and p-coumaric acid, and the presence of a polymer that stained positive for phloroglucinol. In accordance with this, cellulose-deficient cell walls showed a fivefold increase in Klason-type lignin. Thioacidolysis/GC-MS analysis of cellulose-deficient cell walls indicated the presence of a lignin-like polymer with a Syringyl/Guaiacyl ratio of 1.45, which differed from the sensu stricto stress-related lignin that arose in response to shortterm DCB-treatments. Gene expression analysis of these ceils indicated an overexpression of genes specific for the biosynthesis of monolignol units of lignin. A study of stress signaling pathways revealed an overexpression of some of the iasmonate signaling pathway genes, which might trigger ectopic lignification in response to cell wall integrity disruptions. In summary, the structural plasticity of primary cell walls is proven, since a lignification process is possible in response to cellulose impoverishment.

关键词： Cellulose DCB dichlobenil ectopic lignin maize

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