scholarly journals Antimicrobial solid media for screening non-sterile Arabidopsis thaliana seeds

2019 ◽  
Author(s):  
James B. Y. H. Behrendorff ◽  
Guillem Borràs-Gas ◽  
Mathias Pribil
Keyword(s):  
Arabidopsis Thaliana ◽  
Microbial Growth ◽  
Microbial Contamination ◽  
Marker Gene ◽  
Fungal Growth ◽  
Rapid Screening ◽  
Screening Methods ◽  
Surface Sterilization ◽  
Solid Media ◽  
Low Efficiency

AbstractBackgroundStable genetic transformation of plants is a low-efficiency process, and identification of positive transformants usually relies on screening for expression of a co-transformed marker gene. Often this involves germinating seeds on solid media containing a selection reagent. Germination on solid media requires surface sterilization of seeds and careful aseptic technique to prevent microbial contamination, but surface sterilization techniques are time consuming and can cause seed mortality if not performed carefully. We developed an antimicrobial cocktail that can be added to solid media to inhibit bacterial and fungal growth without impairing germination, allowing us to bypass the surface sterilization step.ResultsAdding a combination of terbinafine (1 µM) and timentin (200 mg/L) to solid media delayed the onset of observable microbial growth and did not affect germination of non-sterile seeds from ten different wild-type and mutant Arabidopsis thaliana accessions. The method was also compatible with Nicotiana tabacum germination. Seedlings sown in non-sterile conditions could be maintained on antimicrobial media for up to a week without observable contamination. The antimicrobial cocktail was compatible with rapid screening methods for hygromycin B, phosphinothricin (BASTA) and nourseothricin resistance genes, meaning that positive transformants can be identified from non-sterile seeds in as little as four days after stratification and transferred to soil before the onset of visible microbial contamination.ConclusionThe antimicrobial cocktail presented here delays microbial growth for long enough to permit germination of non-sterile Arabidopsis thaliana seedlings on solid media and it is compatible with rapid screening methods. We were able to select genetic transformants on solid media without seed surface sterilization, eliminating a tedious and time-consuming step.

scholarly journals A study to evaluate the preservative action of Twak Arka in Triphala Kwatha

2021 ◽  
Vol 12 (3) ◽  
pp. 513-517
Author(s):  
Rakshitha D ◽  
Neha Semwal ◽  
Gazala Hussain
Keyword(s):  
Shelf Life ◽  
Microbial Growth ◽  
Microbial Contamination ◽  
Chemical Constituents ◽  
Fungal Growth ◽  
Daily Basis ◽  
Dosage Forms ◽  
Carcinogenic Effects ◽  
Anti Oxidant ◽  
Natural Preservatives

Introduction: Primary dosage forms are basic preparations whose shelf life is a challenge for the practice. Kwatha is a preparation which is easily prone to contamination and can be marketed only by the addition of suitable preservatives to increase the shelf life. So addition of preservatives is being practiced to prolong the shelf life of kwatha but presently using chemical preservatives are harmful to body and even have carcinogenic effects. Hence there aroused a need to find natural preservatives. Arka which is a water distillate consists of essential substances from the crude drug and has longer shelf life. Twak arka possess anti- microbial and anti- oxidant properties and economically cheaper and easily available drug and triphala kwatha being useful in many purposes. In this study an attempt was made to elucidate the preservative action of twak arka in triphala kwatha. Materials and methods: Includes preparation of twak arka, triphala kwatha and conduction of analytical and microbiological study to see the preservative action using SDA and MHA media. Observations and results: Study follows observations over microbial growth of the sample on daily basis where twak arka showed preservative action for 31 days. Aspergillus niger was the fungal growth seen on 32nd day. Discussion: Twak arka owing to its pH, chemical constituents and other properties preserved the triphala kwatha for a stipulated period of time. Conclusion: From the study, it was concluded that the twak arka preserved triphala kwatha without any microbial contamination for 31 days which was added in the concentration of 15%.

Bevacizumab Sterility in Multiple Doses from a Single-Use Vial

2008 ◽  
Vol 42 (10) ◽  
pp. 1425-1428 ◽  
Author(s):  
Kemal Örnek ◽  
Zeynep Ceren Karahan ◽  
Ahmet Ergin ◽  
Alper Tekeli ◽  
Oya Tekeli
Keyword(s):  
Microbial Growth ◽  
Microbial Contamination ◽  
Fungal Growth ◽  
Blood Agar ◽  
Growth Media ◽  
Multiple Use ◽  
Macconkey Agar ◽  
Multiple Doses ◽  
Single Use

Background: Recent reports have demonstrated that refrigerated bevacizumab can be stored for up to 3 weeks at 4 °C without loss of efficacy. There have been no previous reports addressing bevacizumab's sterility when stored and used as multiple doses from a single-use vial. Objective: To evaluate the sterility of bevacizumab when used as multiple doses from a single-use vial. Methods: Four groups of vials were used to simulate the storage and use conditions for bevacizumab. Each group contained 11 doses of 0.2 mL of bevacizumab. One sample from each group was cultured once each day at 37 °C for 10 days; one sample from each group was left for 15 days. MacConkey agar, blood agar, thioglycollate broth, and Sabouraud medium were used to assess bacterial and fungal growth. Results: A total of 44 samples of bevacizumab were included in this study. Each sample was placed on 4 growth media for microbial readings. All samples were found to be negative for microbial growth. No significant differences were observed among the groups. Possible limitations of this study included the number of samples for each group and in vitro design of the study, which might have affected the growth of bacterial organisms. Conclusions: Storage and multiple use of bevacizumab from single-use vials does not seem to result in microbial contamination.

Rapid Screening Methods for Bleeding Disorders. A Three Year Survey

1964 ◽  
Vol 11 (02) ◽  
pp. 506-512 ◽  
Author(s):  
V. A Lovric ◽  
J Margolis
Keyword(s):  
Laboratory Tests ◽  
Capillary Blood ◽  
Screening Tests ◽  
Rapid Screening ◽  
Screening Methods ◽  
Bleeding Disorders ◽  
Routine Laboratory ◽  
Clotting Time ◽  
Kaolin Clotting Time ◽  
In Infants And Children

SummaryAn adaptation of “kaolin clotting time” and prothrombin time for use on haemolysed capillary blood provided simple and sensitive screening tests suitable for use in infants and children. A survey of three year’s experience shows that these are reliable routine laboratory tests for detection of latent coagulation disorders.

scholarly journals Postharvest Supply Chain with Microbial Travelers: a Farm-to-Retail Microbial Simulation and Visualization Framework

2018 ◽  
Vol 84 (17) ◽  
Author(s):  
Claire Zoellner ◽  
Mohammad Abdullah Al-Mamun ◽  
Yrjo Grohn ◽  
Peter Jackson ◽  
Randy Worobo
Keyword(s):  
Supply Chain ◽  
Foodborne Pathogens ◽  
Empirical Data ◽  
Microbial Growth ◽  
Microbial Contamination ◽  
Fresh Produce ◽  
The United States ◽  
Plate Count ◽  
Modeling Tool ◽  
Parameter Ranges

ABSTRACTFresh produce supply chains present variable and diverse conditions that are relevant to food quality and safety because they may favor microbial growth and survival following contamination. This study presents the development of a simulation and visualization framework to model microbial dynamics on fresh produce moving through postharvest supply chain processes. The postharvest supply chain with microbial travelers (PSCMT) tool provides a modular process modeling approach and graphical user interface to visualize microbial populations and evaluate practices specific to any fresh produce supply chain. The resulting modeling tool was validated with empirical data from an observed tomato supply chain from Mexico to the United States, including the packinghouse, distribution center, and supermarket locations, as an illustrative case study. Due to data limitations, a model-fitting exercise was conducted to demonstrate the calibration of model parameter ranges for microbial indicator populations, i.e., mesophilic aerobic microorganisms (quantified by aerobic plate count and here termed APC) and total coliforms (TC). Exploration and analysis of the parameter space refined appropriate parameter ranges and revealed influential parameters for supermarket indicator microorganism levels on tomatoes. Partial rank correlation coefficient analysis determined that APC levels in supermarkets were most influenced by removal due to spray water washing and microbial growth on the tomato surface at postharvest locations, while TC levels were most influenced by growth on the tomato surface at postharvest locations. Overall, this detailed mechanistic dynamic model of microbial behavior is a unique modeling tool that complements empirical data and visualizes how postharvest supply chain practices influence the fate of microbial contamination on fresh produce.IMPORTANCEPreventing the contamination of fresh produce with foodborne pathogens present in the environment during production and postharvest handling is an important food safety goal. Since studying foodborne pathogens in the environment is a complex and costly endeavor, computer simulation models can help to understand and visualize microorganism behavior resulting from supply chain activities. The postharvest supply chain with microbial travelers (PSCMT) model, presented here, provides a unique tool for postharvest supply chain simulations to evaluate microbial contamination. The tool was validated through modeling an observed tomato supply chain. Visualization of dynamic contamination levels from harvest to the supermarket and analysis of the model parameters highlighted critical points where intervention may prevent microbial levels sufficient to cause foodborne illness. The PSCMT model framework and simulation results support ongoing postharvest research and interventions to improve understanding and control of fresh produce contamination.

scholarly journals The efficacy of CRISPR-mediated cytosine base editing with the RPS5a promoter in Arabidopsis thaliana

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Minkyung Choi ◽  
Jae-Young Yun ◽  
Jun-Hyuk Kim ◽  
Jin-Soo Kim ◽  
Sang-Tae Kim
Keyword(s):  
Arabidopsis Thaliana ◽  
Cytidine Deaminase ◽  
Biological Research ◽  
Loss Of Function ◽  
Nucleotide Substitutions ◽  
Viral Origin ◽  
Nonsense Mutations ◽  
Base Editing ◽  
Low Efficiency ◽  
Viable System

AbstractCRISPR/Cas9-mediated genome editing is an important and versatile technology in modern biological research. Recent advancements include base-editing CRISPR tools that enable targeted nucleotide substitutions using a fusion protein comprising a nickase variant of Cas9 and a base deaminase. Improvements in base editing efficiencies and inheritable of edited loci need to be made to make CRISPR a viable system in plants. Here, we report efficiency of cytosine base editors (CBEs) in Arabidopsis thaliana by applying the strong endogenous RPS5a promoter to drive the expression of nickase Cas9 and either rAPOBEC1 from rat (BE3) or the PmCDA1 activation-induced cytidine deaminase from sea lamprey (AIDv2). Compared with the strong heterologous CaMV35S promoter of viral origin, the RPS5a promoter improved CBE efficiency by 32% points with the number of T1 plants showing over 50% conversion ratio when the LFY gene was targeted. CBE induced nonsense mutations in LFY via C-to-T conversion, which resulted in loss-of-function lfy phenotypes; defects in LFY function were associated with the targeted base substitutions. Our data suggest that optimal promoter choice for CBE expression may affect base-editing efficiencies in plants. The results provide a strategy to optimize low-efficiency base editors and demonstrate their applicability for functional assays and trait development in crop research.

scholarly journals Effective medium for in vitro sprouting of the buds and multiplication of the plantlets, and identification of the fungal contaminant associated with the explants of Gnetum

2021 ◽  
Vol 16 (2) ◽  
pp. 001-013
Author(s):  
Abwe Mercy Ngone ◽  
Lawrence Monah Ndam ◽  
Rita Mungfu Njilar ◽  
Doungous Oumar ◽  
Thomas Eku Njock
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Fungal Growth ◽  
Growth Media ◽  
Fungal Contamination ◽  
Surface Sterilization ◽  
Pure Cultures ◽  
Nodal Cuttings ◽  
Baseline Information

Plant tissue culture requires the optimization of growth media. Gnetum, known locally in Cameroon as “Eru” is an indigenous gymnospermous vegetable with diverse medicinal, nutritional, cultural and socio-economic values. This resource is over-exploited and expected to neighboring countries, resulting to increased scarcity in the forest. Preliminary work on the in vitro culture of nodal cuttings was faced by the problem of fungal contamination. It was therefore necessary to isolate and identify the fungal contaminant, optimize the surface sterilization of field material and compose an appropriate medium for sprouting. Pure cultures of the fungus were obtained and grown on Potato Dextrose Agar (PDA) and Sabouraud Dextrose Agar (SDA). The identification was based on the appearance of the fungal growth on plates and also on the microscopic view. This was affected by the use of keys. Gnetum explants were disinfected with the various concentrations of disinfectants, preceded in some instances by pre-treatments, as well as incorporating fungicides in the culture medium. Two different culture media were employed: the Woody Plant Medium (WPM) and the Murashige and Skoog (MS) based establishment medium (Y-1). Gnetum was found to live in association with a complex of Microsporum species. The level of contamination of cultures was reduced from 100% to 40% when pre-treated before disinfection and even lower to 10% by incorporating fungicides in the medium. Sprouting was observed in WPM. This study provides baseline information on the in vitro propagation of Gnetum and thus opens up avenues for more research to be carried out in this field.

Development of New Geopolymer-Based System for Challenging Well Conditions

2021 ◽  
Author(s):  
Siti Humairah Abd Rahman ◽  
Anatoly Medvedev ◽  
Andrey Yakovlev ◽  
Yon Azwa Sazali ◽  
Bipin Jain ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Industry ◽  
Raw Materials ◽  
Critical Role ◽  
Acid Resistance ◽  
Oil Industry ◽  
Rapid Screening ◽  
Fluid Loss ◽  
Screening Methods

Abstract With the development of new oil formations and with the advent of new directions in the global energy sector, new requirements for materials for well construction appear. With the close attention to environmental footprint and unique properties, one of the promising materials for well cementing is geopolymers. Being a relatively new material, they are characterized by low carbon footprint, high acid resistance and attractive mechanical properties. This article is aimed at developing new geopolymer slurries for the oil industry, their characterization and field implementation analysis. With the ultimate goal of developing a methodology for the analysis of raw materials and designing the geopolymer slurries, studies were carried out on various raw materials, including different types of fly ash. Based on the data obtained and rapid screening methods, an approach was developed to formulate a geopolymer composition recipe. Since not all cement additives directly work in geopolymers, special attention was paid to control the thickening time and fluid loss. The methods of XRD, XRF, ICP-MS, density, particle size distribution measurements as well as API methods of cement testing were used to understand the composition and structure of the materials obtained, their properties and design limitations. A special approach was applied to study the acid resistance of the materials obtained and to compare with conventional cements and slags. Using one of the most common sources of aluminosilicate, fly ash, formulations with a density of 13.5 – 16.5 lbm/galUS were tested. A sensitivity analysis showed that the type of activator and its composition play a critical role both in the mechanical properties of the final product and in the solidification time and rheological properties of the product. The use of several samples of fly ash, significantly different in composition, made it possible to formulate the basic rules for the design of geopolymers for the oil industry. An analysis was also carried out on 10 different agents for filtration and 7 moderators to find a working formulation for the temperature range up to 100°C. The samples were systematically examined for changes in composition, strength, and acid resistance was previously measured. Despite the emergence of examples of the use of geopolymers in the construction industry and examples of laboratory testing of geopolymers for the oil industry, to the best of our knowledge, there has been no evidence of pumping geopolymers into a well. Our work is an attempt to develop an adaptation of the construction industry knowledge to the unique high pressure, high temperature conditions of the oil and gas industry. The ambitions of this work go far beyond the laboratory tests and involve yard test experiments.

scholarly journals Microbial Agents Causing Infective Corneal Ulcer and their Anti-microbial Susceptibility pattern

2019 ◽  
Vol 47 (2) ◽  
pp. 1-6
Author(s):  
Azima Aktar Jhuma ◽  
Md Moynul Haque ◽  
Jamil Ahmed ◽  
Shantanu Das ◽  
Tarun Kanti Paul ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Staphylococcus Epidermidis ◽  
Microbial Growth ◽  
Corneal Ulcer ◽  
Bacterial Pathogen ◽  
Fungal Growth ◽  
Penicillium Species ◽  
Corneal Ulcers ◽  
Microbial Agents ◽  
Susceptibility Patterns

This study was designed to identify the microbial agents causing infective corneal ulcer and to carry out the antimicrobial susceptibility patterns of isolated bacteria causing infective corneal ulcer. Out of 80 samples, 67 (83.75%) cases were positive by microscopy and culture. This study showed pure fungal growth in 39 (48.75%) cases, pure bacterial growth in 8 (10%) cases, mixed microbial growth (both fungi and bacteria) in 20 (25%) cases and no growth was observed in 13 (16.25%) cases. Among the fungal isolates, Aspergillus species was the leading agent detected in 37(46.3%) cases followed by Penicillium species in 7 (8.8%) instances. Pseudomonas aeruginosa was the most common bacterial pathogen found in 11 (13.8%) cases followed by Staphylococcus epidermidis present in 9 (11.3%) cases. Gentamicin, Ciprofloxacin and Levofloxacin were found to be better efficacious drugs against most of the bacterial pathogens noted in antimicrobial susceptibility test. This study showed that infective corneal ulcers are caused by both bacterial and fungal agents but fungal agents are more common. The findings of this study would help the ophthal- mologists in evidence based management of their patients of infective corneal ulcer. Bangladesh Med J. 2018 May; 47 (2): 1-6

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