In vitro and in vivo interactions between Erwinia amylovora and related saprophytic bacteria

1975 ◽  
Vol 21 (1) ◽  
pp. 35-41 ◽  
Author(s):  
J. M. Erskine ◽  
L. E. Lopatecki
Keyword(s):  
Erwinia Amylovora ◽  
Virulent Strain ◽  
Sucrose Concentration ◽  
Sugar Content ◽  
Susceptible Host ◽  
The Status ◽  
Highly Virulent ◽  
Host Tissues

Under carefully controlled laboratory conditions, a highly virulent strain of Erwinia amylovora coinhabited susceptible host tissues with a yellow saprophytic bacterium, which was invariably isolated from fire blight infected trees, with or without producing symptoms of the disease depending on the status of a number of environmental factors, both climatic and physiological. In particular, variation of temperature and sucrose concentration determined, independently, the equilibrium of a readily reversible alternation of predominance of the two bacteria.It is suggested that E. amylovora may sometimes exist as an avirulent resident on the surface or within healthy host plants when environmental conditions favor growth of the yellow saprophyte rather than the pathogen. Such conditions, which are more likely to be obtained in midsummer and the fall, include temperature fall or rise below or above the optimum for E. amylovora, decreased humidity or diminution of sap flow, and increased sugar content in the host tissues.

scholarly journals A novel PET tracer 18F-deoxy-thiamine: synthesis, metabolic kinetics, and evaluation on cerebral thiamine metabolism status

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Changpeng Wang ◽  
Siwei Zhang ◽  
Yuefei Zou ◽  
Hongzhao Ma ◽  
Donglang Jiang ◽  
...  
Keyword(s):  
High Performance ◽  
Specific Activity ◽  
High Accumulation ◽  
Metabolic Kinetics ◽  
Thiamine Metabolism ◽  
Pet Tracer ◽  
The Status ◽  
The Brain

Abstract Background Some neuropsychological diseases are associated with abnormal thiamine metabolism, including Korsakoff–Wernicke syndrome and Alzheimer’s disease. However, in vivo detection of the status of brain thiamine metabolism is still unavailable and needs to be developed. Methods A novel PET tracer of 18F-deoxy-thiamine was synthesized using an automated module via a two-step route. The main quality control parameters, such as specific activity and radiochemical purity, were evaluated by high-performance liquid chromatography (HPLC). Radiochemical concentration was determined by radioactivity calibrator. Metabolic kinetics and the level of 18F-deoxy-thiamine in brains of mice and marmosets were studied by micro-positron emission tomography/computed tomography (PET/CT). In vivo stability, renal excretion rate, and biodistribution of 18F-deoxy-thiamine in the mice were assayed using HPLC and γ-counter, respectively. Also, the correlation between the retention of cerebral 18F-deoxy-thiamine in 60 min after injection as represented by the area under the curve (AUC) and blood thiamine levels was investigated. Results The 18F-deoxy-thiamine was stable both in vitro and in vivo. The uptake and clearance of 18F-deoxy-thiamine were quick in the mice. It reached the max standard uptake value (SUVmax) of 4.61 ± 0.53 in the liver within 1 min, 18.67 ± 7.04 in the kidney within half a minute. The SUV dropped to 0.72 ± 0.05 and 0.77 ± 0.35 after 60 min of injection in the liver and kidney, respectively. After injection, kidney, liver, and pancreas exhibited high accumulation level of 18F-deoxy-thiamine, while brain, muscle, fat, and gonad showed low accumulation concentration, consistent with previous reports on thiamine distribution in mice. Within 90 min after injection, the level of 18F-deoxy-thiamine in the brain of C57BL/6 mice with thiamine deficiency (TD) was 1.9 times higher than that in control mice, and was 3.1 times higher in ICR mice with TD than that in control mice. The AUC of the tracer in the brain of marmosets within 60 min was 29.33 ± 5.15 and negatively correlated with blood thiamine diphosphate levels (r = − 0.985, p = 0.015). Conclusion The 18F-deoxy-thiamine meets the requirements for ideal PET tracer for in vivo detecting the status of cerebral thiamine metabolism.

scholarly journals Exposure of ichnovirus particles to digitonin leads to enhanced infectivity and induces fusion from without in an in vitro model system

2007 ◽  
Vol 88 (11) ◽  
pp. 2977-2984 ◽  
Author(s):  
Don Stoltz ◽  
Renée Lapointe ◽  
Andrea Makkay ◽  
Michel Cusson
Keyword(s):  
Outer Membrane ◽  
In Vitro Model ◽  
Model System ◽  
Host Cells ◽  
Fusion Event ◽  
Susceptible Host ◽  
In Vitro Model System ◽  
Vitro Model

Unlike most viruses, the mature ichnovirus particle possesses two unit membrane envelopes. Following loss of the outer membrane in vivo, nucleocapsids are believed to gain entry into the cytosol via a membrane fusion event involving the inner membrane and the plasma membrane of susceptible host cells; accordingly, experimentally induced damage to the outer membrane might be expected to increase infectivity. Here, in an attempt to develop an in vitro model system for studying ichnovirus infection, we show that digitonin-induced disruption of the virion outer membrane not only increases infectivity, but also uncovers an activity not previously associated with any polydnavirus: fusion from without.

In Vitro Germination of Eucalyptus Pollen: Response to Variation in Boric Acid and Sucrose

1989 ◽  
Vol 37 (5) ◽  
pp. 429 ◽  
Author(s):  
BM Potts ◽  
JB Marsden-Smedley
Keyword(s):  
Pollen Tube ◽  
Boric Acid ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Sucrose Concentration ◽  
Response Surfaces ◽  
Tube Growth ◽  
Pollen Competition

The effect of boric acid (0-450 ppm) and sucrose (0-40%) on pollen germination and pollen tube growth in Eucalyptus globulus, E. morrisbyi, E. ovata and E. tirnigera was examined in vitro. Over the con- centrations tested, sucrose had by far the largest effect upon both pollen germination and tube lengths. The optimum sucrose concentration for pollen germination (30%) and pollen tube growth (20%) differed markedly with very little (<lo%) germination occurring in the absence of sucrose. The interaction of sucrose and boric acid was significant. However, in general both pollen germination and pollen tube growth were increased by the addition of up to 100 ppm boric acid, but above this level the response plateauxed. The four species differed significantly in their pattern of response to both boric acid and sucrose and the predicted optima derived from analysis of response surfaces differed between species. The predicted sucrose concentration for optimal germination and growth of E. urnigera pollen was consistently less than the other species and in terms of the optimal level of boric acid for pollen tube growth species can be ranked in the order E. globulus > E. ovata > E. morrisbyi = E. urnigera. Pollen germination and tube growth of all four species on a medium comprising 20% sucrose and 200 ppm boric acid would not differ significantly from the observed maximum response of each species and this could suffice as a generalised medium. However, if only percentage germination is to be assessed 30% sucrose would be preferable. It is argued that subtle interspecific differences in optimal in vitro con- ditions for pollen germination and pollen tube growth are likely to reflect differences in pollen physiology which in vivo may have important implications for the success of hybridisation where pollen competition occurs.

scholarly journals An Overview of Structural Aspects and Health Beneficial Effects of Antioxidant Oligosaccharides

2020 ◽  
Vol 26 (16) ◽  
pp. 1759-1777 ◽  
Author(s):  
Tatiane F. Vieira ◽  
Rúbia C. G. Corrêa ◽  
Rosely A. Peralta ◽  
Regina F. Peralta-Muniz-Moreira ◽  
Adelar Bracht ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Sugar Content ◽  
Animal Health ◽  
Monosaccharide Composition ◽  
Degree Of Polymerization ◽  
Chemical Diversity ◽  
In Vivo Studies

Background: Non-digestible oligosaccharides are versatile sources of chemical diversity, well known for their prebiotic actions, found naturally in plants or produced by chemical or enzymatic synthesis or by hydrolysis of polysaccharides. Compared to polyphenols or even polysaccharides, the antioxidant potential of oligosaccharides is still unexplored. The aim of the present work was to provide an up-to-date, broad and critical contribution on the topic of antioxidant oligosaccharides. Methods: The search was performed by crossing the words oligosaccharides and antioxidant. Whenever possible, attempts at establishing correlations between chemical structure and antioxidant activity were undertaken. Results: The most representative in vitro and in vivo studies were compiled in two tables. Chitooligosaccharides and xylooligosaccharides and their derivatives were the most studied up to now. The antioxidant activities of oligosaccharides depend on the degree of polymerization and the method used for depolymerization. Other factors influencing the antioxidant strength are solubility, monosaccharide composition, the type of glycosidic linkages of the side chains, molecular weight, reducing sugar content, the presence of phenolic groups such as ferulic acid, and the presence of uronic acid, among others. Modification of the antioxidant capacity of oligosaccharides has been achieved by adding diverse organic groups to their structures, thus increasing also the spectrum of potentially useful molecules. Conclusion: A great amount of high-quality evidence has been accumulating during the last decade in support of a meaningful antioxidant activity of oligosaccharides and derivatives. Ingestion of antioxidant oligosaccharides can be visualized as beneficial to human and animal health.

scholarly journals Plasmodium vivax and Drug Resistance

2021 ◽  
Author(s):  
Puji Budi Setia Asih ◽  
Din Syafruddin
Keyword(s):  
Drug Resistance ◽  
Molecular Basis ◽  
Indirect Evidence ◽  
Antimalarial Drugs ◽  
In Vivo Studies ◽  
In Vitro Cultivation ◽  
Radical Cure ◽  
The Status

Resistance to antimalarial drugs is a threat to global efforts to eliminate malaria by 2030. Currently, treatment for vivax malaria uses chloroquine or ACT for uncomplicated P. vivax whereas primaquine is given to eliminate latent liver stage infections (a method known as radical cure). Studies on P. vivax resistance to antimalarials and the molecular basis of resistance lags far behind the P. falciparum as in vitro cultivation of the P. vivax has not yet been established. Therefore, data on the P. vivax resistance to any antimalarial drugs are generated through in vivo studies or through monitoring of antimalarial treatments in mixed species infection. Indirect evidence through drug selective pressure on the parasites genome, as evidenced by the presence of the molecular marker(s) for drug resistance in areas where P. falciparum and P. vivax are distributed in sympatry may reflect, although require validation, the status of P. vivax resistance. This review focuses on the currently available data that may represent the state-of-the art of the P. vivax resistance status to antimalarial to anticipate the challenge for malaria elimination by 2030.

scholarly journals Cerenkov luminescence imaging is an effective preclinical tool for assessing colorectal cancer PD-L1 levels in vivo

2020 ◽  
Author(s):  
Sheng Zhao ◽  
Wen-Bin Pan ◽  
Hui-Jie Jiang ◽  
Rong-Jun Zhang ◽  
Hao Jiang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Monoclonal Antibody ◽  
Competitive Inhibition ◽  
Specific Binding ◽  
Luminescence Imaging ◽  
Tumor Bearing ◽  
Cerenkov Luminescence Imaging ◽  
The Status

Abstract Background : Preclinical and clinical studies have demonstrated that immunotherapy has effectively delayed tumor progression, and the clinical outcomes of anti-PD-1/PD-L1 therapy were related to PD-L1 expression level in the tumors. A 131 I-labeled anti-PD-L1 monoclonal antibody tracer, 131 I-PD-L1-Mab, was developed to study the target ability of non-invasive Cerenkov luminescence imaging in colorectal cancer xenograft mice.Method: Anti-PD-L1 monoclonal antibody labeled with 131 I( 131 I-PD-L1-Mab), and in vitro binding assays were used to evaluate the affinity of 131 I-PD-L1-Mab to PD-L1 and their binding level to different colorectal cancer cells, and compared with flow cytometry, western blot analysis, and immunofluorescence staining. The clinical application value of 131 I-PD-L1-Mab was evaluated through biodistribution and Cerenkov luminescence imaging, and different tumor-bearing models expressing PD-L1 were evaluated.Results: 131 I-PD-L1-Mab showed high affinity to PD-L1, and the equilibrium dissociation constant was 1.069×10 -9 M. The competitive inhibition assay further confirmed the specific binding ability of 131 I-PD-L1-Mab. In four different tumor-bearing models with different PD-L1 expression, the biodistribution and Cerenkov luminescence imaging showed that the RKO tumors demonstrated the highest uptake of the tracer 131 I-PD-L1-Mab, with a maximum uptake of 1.613 ± 0.738% ID/g at 120 h.Conclusions: There is a great potential for 131 I-PD-L1-Mab noninvasive Cerenkov luminescence imaging to assess the status of tumor PD-L1 expression and select patients for anti-PD-L1 targeted therapy.

scholarly journals Identification of a Novel Virulence Factor in Recombinant Pneumonia Virus of Mice

2007 ◽  
Vol 81 (17) ◽  
pp. 9490-9501 ◽  
Author(s):  
Christine D. Krempl ◽  
Anna Wnekowicz ◽  
Elaine W. Lamirande ◽  
Giw Nayebagha ◽  
Peter L. Collins ◽  
...  
Keyword(s):  
Virulence Factor ◽  
Reverse Genetics ◽  
Fluorescent Protein ◽  
Vaccine Development ◽  
Virulent Strain ◽  
Consensus Sequence ◽  
Cytoplasmic Tail ◽  
Syncytial Virus

ABSTRACT Pneumonia virus of mice (PVM) is a murine relative of human respiratory syncytial virus (HRSV). Here we developed a reverse genetics system for PVM based on a consensus sequence for virulent strain 15. Recombinant PVM and a version engineered to express green fluorescent protein replicated as efficiently as the biological parent in vitro but were 4- and 12.5-fold attenuated in vivo, respectively. The G proteins of HRSV and PVM have been suggested to contribute to viral pathogenesis, but this had not been possible to study in a defined manner in a fully permissive host. As a first step, we evaluated recombinant mutants bearing a deletion of the entire G gene (ΔG) or expressing a G protein lacking its cytoplasmic tail (Gt). Both G mutants replicated as efficiently in vitro as their recombinant parent, but both were nonpathogenic in mice at doses that would otherwise be lethal. We could not detect replication of the ΔG mutant in mice, indicating that its attenuation is based on a severe reduction in the virus load. In contrast, the Gt mutant appeared to replicate as efficiently in mice as its recombinant parent. Thus, the reduction in virulence associated with the Gt mutant could not be accounted for by a reduction in viral replication. These results identified the cytoplasmic tail of G as a virulence factor whose effect is not mediated solely by the viral load. In addition to its intrinsic interest, a recombinant virus that replicates with wild-type-like efficiency but does not cause disease defines optimal properties for vaccine development.

Implementation of Quality by Design: A Review

2019 ◽  
Vol 6 (2) ◽  
pp. 99-111
Author(s):  
Deepika Purohit ◽  
Manisha Saini ◽  
Parijat Pandey ◽  
Swagat Tripathy ◽  
Harish Dureja
Keyword(s):  
Quality By Design ◽  
Generic Drugs ◽  
Therapeutic Benefit ◽  
Pharmaceutical Products ◽  
In Vitro Tests ◽  
Performance Quality ◽  
The Status ◽  
Regulatory Bodies

Background: In pharmaceutical terms, quality means a product free from any contamination and delivers the therapeutic benefit specified in the label at a reproducible rate which can be assessed by carrying out in vivo or in vitro tests for evaluation of performance. Quality by Design (QbD) is a necessary tool in pharmaceutical environment for having product/process/method impregnated with quality. QbD is a move toward drug development that ensures the preplanned product specifications by providing guidance for architecting the manufacturing processes and formulation. Methodology: It has provided the solution to support both the regulatory bodies and industry to shift towards added proactive and scientific approach. QbD is the greatest solution to construct quality in all pharmaceutical products, while at the same time, making it a part of the system is also a key challenge for the industry. By using QbD concept, regulators as well as industries are making a move in geometric progress in bringing quality products. Regulatory bodies across the world are showing significant attention to QbD. Conclusion: Therefore, an attempt has been made to highlight quality by designing generic drugs and its implications to pharmaceutical industry including clinical trials, pharmaceutical validation processes and in biologics and also to provide a brief description on the status of QbD in India and as well as in Asia.

Mechanisms of pathogenesis in Sclerotium bataticola on sunflowers. II. Pectolytic and cellulolytic enzyme production in vitro and in vivo

1970 ◽  
Vol 48 (6) ◽  
pp. 1073-1077 ◽  
Author(s):  
Yu-Ho Chan ◽  
W. E. Sackston
Keyword(s):  
Enzyme Production ◽  
Pectin Methylesterase ◽  
Cellulolytic Enzyme ◽  
Culture Filtrates ◽  
Healthy Control ◽  
Host Tissues

Pectin methylesterase (PME), endopolygalacturonase (Endo-PG), exopolygalacturonase (Exo-PG), pectin trans-eliminase (PTE), polygalacturonase trans-eliminase (PGTE), cellulase, and cellobiase activities were investigated in culture filtrates of Sclerotium bataticola, and in extracts of inoculated and uninoculated sunflower stems. All of the enzymes except PTE were produced in culture filtrates of the pathogen and in diseased host tissues. Only PME was detected in healthy control plants.

scholarly journals Characterization of Specific Immune Responses of Mice Inoculated with Recombinant Vaccinia Virus Expressing an 18-Kilodalton Outer Membrane Protein of Brucella abortus

2000 ◽  
Vol 7 (1) ◽  
pp. 114-118 ◽  
Author(s):  
Ramesh Vemulapalli ◽  
Silvio Cravero ◽  
Christine L. Calvert ◽  
Thomas E. Toth ◽  
Nammalwar Sriranganathan ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Vaccinia Virus ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Brucella Abortus ◽  
Virulent Strain ◽  
Shuttle Vector ◽  
Protein Fusion

ABSTRACT Using the shuttle vector pMCO2 and the vaccinia virus wild-type WR strain, we constructed a recombinant virus expressing an 18-kDa outer membrane protein of Brucella abortus. BALB/c mice inoculated with this virus produced 18-kDa protein-specific antibodies, mostly of immunoglobulin G2a isotype, and in vitro stimulation of splenocytes from these mice with purified maltose binding protein–18-kDa protein fusion resulted in lymphocyte proliferation and gamma interferon production. However, these mice were not protected against a challenge with the virulent strain B. abortus2308. Disruption of the 18-kDa protein's gene in vaccine strainB. abortus RB51 did not affect either the strain's protective capabilities or its in vivo attenuation characteristics. These observations suggest that the 18-kDa protein plays no role in protective immunity.

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