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61.
A new series of complexes of cobalt(II) fluoride, nickel(II) fluoride, copper(II) fluoride and zinc(II) fluoride with imidazole were synthesized and characterized by elemental analysis, molar conductance, magnetic moments, IR and electronic absorption measurements. Based on elemental and spectral data, the complexes were found to be of [M(im)6]F2 · XH2O type, where M is Co(II), Ni(II), Cu(II) and Zn(II) and X 4-5. The magnetic moments and spectral data suggested that all the complexes possessed an octahedral geometry. The crystal structure of the nickel complex, [Ni(im)6]F2 · 5H2O, is also reported in which nickel atom is surrounded by six nitrogen atoms of imidazole. Strong intra- and inter-molecular hydrogen bonding exists between fluoride ions (uncoordinated), nitrogen of imidazole and the -OH of water molecules. 相似文献
62.
Basharat Ali Anjum Nasim Sabri Karin Ljung Shahida Hasnain 《World journal of microbiology & biotechnology》2009,25(3):519-526
Sixteen Bacillus strains isolated from rhizosphere, histoplane and phyllosphere of different plant species were identified by 16S rDNA gene
sequencing and evaluated for in vitro auxin production as well as growth stimulation of Vigna radiata (L.) Wilczek. Auxin production by Bacillus spp. in L-broth medium supplemented with 1,000 μg ml−1
L-tryptophan ranges from 0.60 to 3.0 μg IAA ml−1 as revealed by gas chromatography and mass spectrometric (GC–MS) analysis. Rhizospheric isolates exhibit relatively more
IAA synthesis than histoplane and phyllosphere isolates. Plant microbe interaction experiments conducted under gnotobiotic
conditions recorded 55.55, 46.46 and 46.20% increase in shoot length with Bacillus megaterium MiR-4, B. pumilus NpR-1 and B. subtilis TpP-1, respectively, over control. Bacillus inoculations also increased shoot fresh weight with B. megaterium MiR-4 (60.94%) and B. pumilus NpR-1 (37.76%). Highly significant positive correlation between auxin production analyzed by GC–MS and shoot length (r = 0.687**, P = 0.01) and shoot fresh weight (r = 0.703**, P = 0.01) was noted under gnotobiotic conditions. Similarly, significant correlation was also found between auxin production
by Bacillus spp. (GC–MS analysis) and different growth parameters such as shoot length (r = 0.495*, P = 0.05), number of pods (r = 0.498*, P = 0.05) and grain weight (r = 0.537*, P = 0.05) at full maturity under natural wire house conditions. Results showed that auxin production potential of plant associated
Bacillus spp. can be effectively exploited to enhance the growth and yield of V. radiata. 相似文献
63.
Harry S. Courtney Yi Li Waleed O. Twal W. Scott Argraves 《The Journal of biological chemistry》2009,284(19):12966-12971
The adhesion of bacteria to host tissues is often mediated by interactions
with extracellular matrices. Herein, we report on the interactions of the
group A streptococcus, Streptococcus pyogenes, with the extracellular
matrix protein fibulin-1. S. pyogenes bound purified fibulin-1 in a
dose-dependent manner. Genetic ablation of serum opacity factor (SOF), a
virulence determinant of S. pyogenes, reduced binding by ∼50%,
and a recombinant peptide of SOF inhibited binding of fibulin-1 to
streptococci by ∼45%. Fibulin-1 bound to purified SOF2 in a dose-dependent
manner with high affinity (Kd = 1.6 nm). The
fibulin-1-binding domain was localized to amino acid residues 457–806 of
SOF2, whereas the fibronectin-binding domain is contained within residues
807–931 of SOF2, indicating that these two domains are separate and
distinct. Fibulin-1 bound to recombinant SOF from M types 2, 4, 28, and 75 of
S. pyogenes, indicating that the fibulin-1-binding domain is likely
conserved among SOF from different serotypes. Mixed binding experiments
suggested that gelatin, fibronectin, fibulin-1, and SOF form a quaternary
molecular complex that enhanced the binding of fibulin-1. These data indicate
that S. pyogenes can interact with fibulin-1 and that SOF is a major
streptococcal receptor for fibulin-1 but not the only receptor. Such
interactions with fibulin-1 may be involved in the adhesion of S.
pyogenes to extracellular matrices of the host.Adhesion of bacteria to host surfaces is the first stage in establishing
bacterial infections in the human host, and a variety of molecular mechanisms
are utilized to initiate adhesion. A common mechanism for adhesion involves
interactions between bacterial adhesins and components of the extracellular
matrices of the host. The identification and characterization of microbial
surface components recognizing adhesive matrix molecules (MSCRAMM) has led to
important advances in vaccines and immunotherapies for preventing and treating
bacterial infections (1).The group A streptococcus, Streptococcus pyogenes, is a major
human pathogen causing diseases ranging from relative minor infections such as
pharyngitis and cellulitis to severe infections with high levels of morbidity
and mortality such as necrotizing fasciitis and toxic shock syndrome
(2). This pathogen expresses
adhesins that interact with various components of the extracellular matrix
including laminin, elastin, fibronectin, fibrinogen, and collagen
(3–7).
The interactions between fibronectin and S. pyogenes have been
intensely studied, and these investigations have revealed at least 10
different streptococcal proteins that bind fibronectin
(4).Serum opacity factor
(SOF)2 is a major
fibronectin-binding protein that is involved in adhesion to host cells
(8–11).
SOF is a virulence determinant that is expressed by approximately half of the
clinical isolates of S. pyogenes
(8). SOF opacifies serum by
binding and displacing apoA-I in high density lipoproteins
(8,
12–15).
SOF is covalently linked to the streptococcal cell wall via an LPSTG sortase
recognition site and is also released in a soluble form. SOF has two
functionally distinct domains, an N-terminal domain that opacifies serum and a
C-terminal domain that binds fibronectin. The role of SOF in adhesion involves
both its C-terminal fibronectin-binding domain and an N-terminal region (see
Fig. 1 for a schematic of
structure) (9,
11). However, the nature of
the interactions between the N-terminal region of SOF and host components is
not well characterized.Open in a separate windowFIGURE 1.A, a schematic of the structure of SOF and its functional domains
is shown. The assignment of functional domains are based on the findings of
Rakonjac et al. (33),
Kreikemeyer et al.
(34), Courtney et al.
(8,
13), and results presented in
this work. Fn, fibronectin. B, the data for the binding of
SOF peptides to fibronectin are from previous publications
(8,
13), and the data for
fibulin-1 are from the present work.Herein, we report on the interactions between a truncated form of SOF in
which its fibronectin-binding domain has been deleted and the extracellular
matrix protein fibulin-1. Fibulin-1 is a member of the fibulin family that
currently consists of seven glycoproteins. All fibulins contain epidermal
growth factor-like repeats and a unique fibulin-type module at its C terminus
that define this family (16,
17). Fibulin-1 is found within
the extracellular matrices and in human plasma at 30–50 μg/ml
(18). It interacts with many
of the components of the extracellular matrix including fibronectin, laminin,
fibrinogen, nidogen-1, endostatin, aggrecan, and versican
(16,
19). Due to its intimate
relationship with the extracellular matrix, it is not surprising that the
defects in fibulin-1 have a wide-ranging impact. Genetic evidence suggests
that fibulin-1 is involved in tissue organization, the maturation and
maintenance of blood vessels, and multiple embryonic pathways
(16,
20–22).Although it has been established that many of the other components of the
extracellular matrix can interact with bacteria, there has been no previous
report on the binding of fibulins to bacteria. Our findings indicate that
fibulin-1 does bind to streptococci and that SOF is a major streptococcal
receptor for fibulin-1. 相似文献
64.
El‐Sayed M. El‐Sayed Ahmed M. Mansour Waleed S. El‐Sawy 《Journal of biochemical and molecular toxicology》2017,31(11)
Doxorubicin (DOX) exerts toxic effects in several organs particularly kidney. The present study aimed to assess the protective effect of proanthocyanidins (PAs) against DOX‐induced nephrotoxicity in rats. A single dose of DOX (7.5 mg/kg, i.v.) significantly increased kidney weight, kidney/body weight ratio, serum urea, creatinine, tumor necrosis factor alpha levels, and kidney contents of malondialdehyde, nitric oxide, cyclooxygenase‐2, and caspase‐3 activity with significant reduction in final body weight, serum albumin, kidney contents of reduced glutathione (GSH), and superoxide dismutase activity as compared with control group. In contrast, pretreatment with PAs (200 mg/kg, p.o.) for 14 days before DOX and for 7 days after DOX ameliorated kidney function and oxidative stress parameters. Histopathological evidence confirmed the protective effects of PAs from the tissue damage induced by DOX. In conclusion, PAs have a multi‐nephroprotective effect that might be attributed to its antioxidant, anti‐inflammatory, and antiapoptoic activities. 相似文献
65.
William Matlock Kevin K. Chau Manal AbuOun Emma Stubberfield Leanne Barker James Kavanagh Hayleah Pickford Daniel Gilson Richard P. Smith H. Soon Gweon Sarah J. Hoosdally Jeremy Swann Robert Sebra Mark J. Bailey Timothy E. A. Peto Derrick W. Crook Muna F. Anjum Daniel S. Read A. Sarah Walker Nicole Stoesser Liam P. Shaw REHAB consortium 《The ISME journal》2021,15(8):2322
F-type plasmids are diverse and of great clinical significance, often carrying genes conferring antimicrobial resistance (AMR) such as extended-spectrum β-lactamases, particularly in Enterobacterales. Organising this plasmid diversity is challenging, and current knowledge is largely based on plasmids from clinical settings. Here, we present a network community analysis of a large survey of F-type plasmids from environmental (influent, effluent and upstream/downstream waterways surrounding wastewater treatment works) and livestock settings. We use a tractable and scalable methodology to examine the relationship between plasmid metadata and network communities. This reveals how niche (sampling compartment and host genera) partition and shape plasmid diversity. We also perform pangenome-style analyses on network communities. We show that such communities define unique combinations of core genes, with limited overlap. Building plasmid phylogenies based on alignments of these core genes, we demonstrate that plasmid accessory function is closely linked to core gene content. Taken together, our results suggest that stable F-type plasmid backbone structures can persist in environmental settings while allowing dramatic variation in accessory gene content that may be linked to niche adaptation. The association of F-type plasmids with AMR may reflect their suitability for rapid niche adaptation.Subject terms: Environmental microbiology, Genomics 相似文献
66.
Metal/metalloid stress tolerance in plants: role of ascorbate,its redox couple,and associated enzymes 总被引:1,自引:0,他引:1
Naser A. Anjum Sarvajeet S. Gill Ritu Gill Mirza Hasanuzzaman Armando C. Duarte Eduarda Pereira Iqbal Ahmad Renu Tuteja Narendra Tuteja 《Protoplasma》2014,251(6):1265-1283
The enhanced generation of reactive oxygen species (ROS) under metal/metalloid stress is most common in plants, and the elevated ROS must be successfully metabolized in order to maintain plant growth, development, and productivity. Ascorbate (AsA) is a highly abundant metabolite and a water-soluble antioxidant, which besides positively influencing various aspects in plants acts also as an enigmatic component of plant defense armory. As a significant component of the ascorbate-glutathione (AsA-GSH) pathway, it performs multiple vital functions in plants including growth and development by either directly or indirectly metabolizing ROS and its products. Enzymes such as monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) and dehydroascorbate reductase (DHAR, EC 1.8.5.1) maintain the reduced form of AsA pool besides metabolically controlling the ratio of AsA with its oxidized form (dehydroascorbate, DHA). Ascorbate peroxidase (APX, EC 1.11.1.11) utilizes the reduced AsA pool as the specific electron donor during ROS metabolism. Thus, AsA, its redox couple (AsA/DHA), and related enzymes (MDHAR, DHAR, and APX) cumulatively form an AsA redox system to efficiently protect plants particularly against potential anomalies caused by ROS and its products. Here we present a critical assessment of the recent research reports available on metal/metalloid-accrued modulation of reduced AsA pool, AsA/DHA redox couple and AsA-related major enzymes, and the cumulative significance of these antioxidant system components in plant metal/metalloid stress tolerance. 相似文献
67.
Larsen N Vogensen FK Gøbel R Michaelsen KF Abu Al-Soud W Sørensen SJ Hansen LH Jakobsen M 《FEMS microbiology ecology》2011,75(3):482-496
The effect of probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 on the composition of the Lactobacillus group, Bifidobacterium and the total bacterial population in feces from young children with atopic dermatitis was investigated. The study included 50 children randomized to intake of one of the probiotic strain or placebo. Microbial composition was characterized by denaturing gradient gel electrophoresis, quantitative PCR and, in a subset of subjects, by pyrosequencing of the 16S rRNA gene. The core population of the Lactobacillus group was identified as Lactobacillus gasseri, Lactobacillus fermentum, Lactobacillus oris, Leuconostoc mesenteroides, while the bifidobacterial community included Bifidobacterium adolescentis, Bifidobacterium bifidum, Bifidobacterium longum and Bifidobacterium catenulatum. The fecal numbers of L. acidophilus and B. lactis increased significantly after intervention, indicating survival of the ingested bacteria. The levels of Bifidobacterium correlated positively (P=0.03), while the levels of the Lactobacillus group negatively (P=0.01) with improvement of atopic eczema evaluated by the Severity Scoring of Atopic Dermatitis index. This correlation was observed across the whole study cohort and not attributed to the probiotic intake. The main conclusion of the study is that administration of L. acidophilus NCFM and B. lactis Bi-07 does not affect the composition and diversity of the main bacterial populations in feces. 相似文献
68.
Shiwali Sharma Anwar Shahzad Altaf Ahmad Laiqa Anjum 《Acta Physiologiae Plantarum》2014,36(9):2331-2344
The present study reports a high frequency in vitro propagation protocol through apical bud sprouting and basal organogenic nodule formation in shoot tip explants of Decalepis hamiltonii, an endemic and endangered medicinal liana. Among different combinations of plant growth regulators (PGRs) and growth additives, maximum of 8.20 shoots per explant with mean shoot length of 6.54 cm were induced on Murashige and Skoog’s medium (MS) supplemented with 5.0 µM 6-benzyladenine (BA) + 0.5 µM indole-3-acetic acid (IAA) + 30.0 µM adenine sulphate (ADS) through apical bud sprouting. On single cytokinin treatment explants did not exhibit good multiplication but showed nodulation (N1) from the basal cut end similar to cytokinin–auxin combination (N2). Between two types of nodular tissues, N2 was proved to be better for maximum shoot regeneration (15.40 shoots per explant) and shoot length (4.56 cm) when cultured on MS medium supplemented with 5.0 µM BA, 0.5 µM IAA, 30.0 µM ADS and 1.0 µM gibberellic acid (GA3). Microshoots were efficiently rooted on half-strength MS medium supplemented with 2.5 μM α-naphthalene acetic acid (NAA). After successful acclimatization in Soilrite, 95.10 % plantlets were survived in field conditions. Histological investigation proved useful in ascertaining the callogenic nature of the regenerating nodular tissue formed at the basal cut end of shoot tip explant. Acclimatized plantlets were studied for the estimation of chlorophyll and carotenoid content as well as the net photosynthetic rate (PN) during subsequent days of transfer to ex vitro condition. Moreover, acclimatization had a significant effect on biomass production and the synthesis of 2-hydroxy-4-methoxy benzaldehyde (2HMB). Maximum fresh weight (3.78 gm/plant), dry weight (0.39 gm/plant) of roots and 2HMB content (15.94 µg/ml of extract) were noticed after 8 weeks of acclimatization. 相似文献
69.
70.
Anjum Zafar Fan Wu Kristine Hardy Jasmine Li Wen Juan Tu Robert McCuaig Janelle Harris Kum Kum Khanna Joanne Attema Philip A. Gregory Gregory J. Goodall Kirsti Harrington Jane E. Dahlstrom Tara Boulding Rebecca Madden Abel Tan Peter J. Milburn Sudha Rao 《Molecular and cellular biology》2014,34(16):2961-2980