scholarly journals Dark Field Microscopy-Based Biosensors for the Detection of E. coli in Environmental Water Samples

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4652
Author(s):  
Rita La Spina ◽  
Diana C. António ◽  
Cloe Desmet ◽  
Andrea Valsesia ◽  
Radoslaw Bombera ◽  
...  
Keyword(s):  
Distribution Systems ◽  
Pathogenic Bacteria ◽  
Quantitative Polymerase Chain Reaction ◽  
Dark Field ◽  
Negative Control ◽  
Bacillus Sp ◽  
E Coli ◽  
Sensing Platform ◽  
Dark Field Microscopy ◽  
Field Samples

Development of sensitive methods for the determination of E. coli bacteria contamination in water distribution systems is of paramount importance to ensure the microbial safety of drinking water. This work presents a new sensing platform enabling the fast detection of bacteria in field samples by using specific antibodies as the biorecognition element and dark field microscopy as the detection technique. The development of the sensing platform was performed using non-pathogenic bacteria, with the E. coli DH5α strain as the target, and Bacillus sp. 9727 as the negative control. The identification of the captured bacteria was made by analyzing the dark field microscopy images and screening the detected objects by using object circularity and size parameters. Specificity tests revealed the low unspecific attachment of either E. coli over human serum albumin antibodies (negative control for antibody specificity) and of Bacillus sp. over E. coli antibodies. The system performance was tested using field samples, collected from a wastewater treatment plant, and compared with two quantification techniques (i.e., Colilert-18 test and quantitative polymerase chain reaction (qPCR)). The results showed comparable quantification capability. Nevertheless, the present method has the advantage of being faster, is easily adaptable to in-field analysis, and can potentially be extended to the detection of other bacterial strains.

scholarly journals A Novel Approach of Targeted Immunotherapy against Adenocarcinoma Cells with Nanoparticles Modified by CD16 and MUC1 Aptamers

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Lianyuan Yu ◽  
Yan Hu ◽  
Jinhong Duan ◽  
Xian-Da Yang
Keyword(s):  
Nk Cells ◽  
Cancer Cells ◽  
Dark Field ◽  
Negative Control ◽  
Mucin 1 ◽  
Novel Approach ◽  
Adenocarcinoma Cells ◽  
Dark Field Microscopy ◽  
Average Size ◽  
Nk Cytotoxicity

Mucin 1 (MUC1) is a potentially important target of cancer therapy, being a glycoprotein that is overexpressed on cell surface of many types of adenocarcinomas, including breast, ovarian, colon, lung, and prostatic cancers. Several MUC1-targeted drug delivery systems have been developed and reported, but mobilizing natural killer cells (NK) to fight against MUC1-positive tumor has not been attempted. In this study, we introduced a novel amphipathic nanoparticle (NP) for enhancing the NK cytotoxicity to MUC1-positive cancer cells. The amphipathic NP had CD16 and MUC1 aptamers on its surface and was designed to bind with both the CD16-positive NK cells and the MUC1-positive tumor cells and pull the two types of cells close to each other. The fabricated amphipathic NP had an average size of 574 nm. The aptamers’ conjugation with the NP was confirmed by DNA hybridization experiments. Dark-field microscopy revealed that the amphipathic NP could recruit more NK cells to the vicinity of MUC1-positive cancer cells. Additionally, the amphipathic NP significantly enhanced the NK cytotoxicity to MUC1-positive cancer cellsp<0.01, but not that to the MUC1-negative control cells. The results suggest that NK cells may potentially be mobilized to selectively fight against MUC1-positive cancer cells.

scholarly journals Interleukin gene expression in broiler chickens infected by different Escherichia coli serotypes

2021 ◽  
pp. 2727-2734
Author(s):  
Reham Elnagar ◽  
Rasha Elkenany ◽  
Gamal Younis
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Broiler Chickens ◽  
Quantitative Polymerase Chain Reaction ◽  
Clinical Signs ◽  
Negative Control Group ◽  
Negative Control ◽  
Control Group ◽  
E Coli ◽  
High Prevalence

Background and Aim: Escherichia coli is the cause of avian colibacillosis, a significant threat to the poultry industry and public health. Thus, this study investigated the prevalence of E. coli in diseased chicken broilers, pathological effects of these bacteria, and interleukin (IL) gene expression of different serotypes of E. coli (O78, O26, O44, and O55) on experimentally infected chickens. Materials and Methods: A total of 295 organ samples (liver, lungs, heart, and spleen) from 59 diseased broiler chickens were used for conventional identification of E. coli. Chickens were orally infected with one of the following E. coli serotypes (O78, O26, O44, or O55) and examined for clinical signs, mortality, macroscopic and microscopic lesions, and IL gene expression using real-time quantitative polymerase chain reaction. Results: E. coli was isolated from 53.2% of broiler chicken organs with a high prevalence in lungs (26.1%). The most prevalent serotypes were O78, O26, O44, O55, O157, and O127 prevalence of 27.8, 22.2, 16.7, 16.7, 5.6, and 5.6%, respectively. In the experimental design, five groups (G1-G5) of birds were established. G1 served as the negative control group, while G2-G5 were challenged orally with E. coli O78, O26, O55, or O44, respectively. Chickens infected with E. coli O78 or O26 showed significant clinical signs in comparison to the other infected birds. Mortality (13.3%) was only observed in birds infected with E. coli O78. Necropsy of dead birds after E. coli O78 infection showed pericarditis, enteritis, airsacculitis, and liver and lung congestion. More severe histopathological changes were observed in intestines, spleen, liver, and lung from chickens infected with either E. coli O78 or O26 than for birds infected with other serotypes. On the 2nd day post-infection, E. coli challenge, particularly with E. coli O78, displayed significantly upregulated levels of ileal IL-6 and IL-8, but ileal IL-10 level tended to be downregulated in comparison to the control group. Conclusion: This study assessed the application of cytokines as therapeutic agents against infectious diseases, particularly colibacillosis.

scholarly journals Transfer of Escherichia coli O157:H7 to Spinach by House Flies, Musca domestica (Diptera: Muscidae)

2013 ◽  
Vol 103 (4) ◽  
pp. 373-380 ◽  
Author(s):  
Lakmini Wasala ◽  
Justin L. Talley ◽  
Udaya DeSilva ◽  
Jacqueline Fletcher ◽  
Astri Wayadande
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Quantitative Polymerase Chain Reaction ◽  
Escherichia Coli O157 ◽  
Human Pathogens ◽  
House Flies ◽  
E Coli ◽  
Filth Flies ◽  
Microscopy Techniques ◽  
Nutrition Source

Filth flies are known mechanical vectors of pathogenic bacteria in hospital and restaurant settings, but their role as vectors for disseminating microbes to plants has not been demonstrated. Escherichia coli O157:H7 deposition by flies onto spinach was studied using molecular, microbiological, and microscopy techniques. Relative quantitative polymerase chain reaction studies showed that bacteria acquired by flies from contaminated cattle manure and deposited in regurgitation spots on leaves survived and multiplied. Scanning electron microscopy of the regurgitation spots of flies exposed to manure inoculated with E. coli suggested the multiplication of bacteria-like organisms within the spots. This finding implies that the bacteria were active and is consistent with a hypothesis that regurgitation spots serve as a nutrition source allowing E. coli O157:H7 to survive on the spinach phylloplane. E. coli O157:H7 persisted on fly body surfaces up to 13 days after exposure to acquisition sources, suggesting that fly cuticular surfaces are conducive to the growth of this pathogen. These results are consistent with the hypothesis of bioenhanced transmission of human pathogens by house flies and suggest that filth flies may affect the microbial safety of fresh produce.

scholarly journals Keberadaan bakteri patogen pada sampel pangan jajanan anak sekolah dasar di Pulau Sapeken, Sumenep, Jawa Timur

2019 ◽  
Vol 23 (2) ◽  
pp. 68 ◽  
Author(s):  
Ivani Dayanara ◽  
Retno Kawuri ◽  
Dwi Ariani Yulihastuti
Keyword(s):  
Escherichia Coli ◽  
School Children ◽  
Pathogenic Bacteria ◽  
Microbial Contamination ◽  
Plate Count ◽  
Most Probable Number ◽  
Bacillus Sp ◽  
Probable Number ◽  
Safety Testing ◽  
E Coli

School children snacks are food that is found and routinely consumed by children in the school environment.Good and healthy food must be free from hazardous and toxic materials, such as microbial contamination,chemicals and other materials. The consumed food must meet the microbial contamination requirementsbased on SNI (Standar Nasional Indonesia) safety testing. Pathogenic bacteria still a serious problem invarious countries including Indonesia, since they are capable of causing foodborne diseases. Sapeken Islandis located in Sapeken Village, Sapeken District, Sumenep Regency, East Java Province. The purpose of thestudy was to determine the presence of pathogenic bacteria in samples of snacks for school children onSapeken Island. The method used was the Most Probable Number (MPN) for Escherichia coli, Test Numberof Bacillus sp., Test Number of Staphyllococcus sp., Identification of Salmonella, and Total Plate Count(TPC). The test results obtained in the MPN of Escherichia coli included SD M (9.9 ± 3.8) MPN / g, SD 5(8.68 ± 2.73) MPN / g, SD IT (5.08 ± 0.66) MPN / g, and SD 4 (4.26 ± 2.44) MPN / g exceed the SNI limit.JURNAL BIOLOGI UDAYANA 23(2): 60-71 P ISSN: 1410-5292 E ISSN: 2599-285661The results of JPT E. coli in snack empek-empek at SD I and SD 2, and JPT E. coli ojek in all elementaryschools is <3 MPN / g. The results of the empek-empek and ojek samples in all elementary schools for alltests with the parameter number Bacillus sp. is <1 x 103, the number of Staphylococcus sp. is <1 x 102,Salmonella identification is negative, TPC is <1 x 105 CFU / g. The conclusion of the study is snack forschool children (empek-empek) and ojek on Sapeken Island does not contain contamination of pathogenicbacteria Escherichia coli, Bacillus sp., Staphylococcus sp., Salmonella identification, and TPC, except forthe JPT E. coli test on empek empek in SD M, SD 5, SD IT and SD 4 that exceed SNI limits.

Elastic Scattering in Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 252-253
Author(s):  
J. Langmore ◽  
M. Isaacson ◽  
J. Wall ◽  
A. V. Crewe
Keyword(s):  
Electron Microscopy ◽  
Elastic Scattering ◽  
Cross Section ◽  
Quantum Noise ◽  
Dark Field ◽  
Elastic Cross Section ◽  
Biological Molecules ◽  
Dark Field Microscopy ◽  
Field Systems ◽  
Effects Of Radiation

High resolution dark field microscopy is becoming an important tool for the investigation of unstained and specifically stained biological molecules. Of primary consideration to the microscopist is the interpretation of image Intensities and the effects of radiation damage to the specimen. Ignoring inelastic scattering, the image intensity is directly related to the collected elastic scattering cross section, σɳ, which is the product of the total elastic cross section, σ and the eficiency of the microscope system at imaging these electrons, η. The number of potentially bond damaging events resulting from the beam exposure required to reduce the effect of quantum noise in the image to a given level is proportional to 1/η. We wish to compare η in three dark field systems.

Simulated Dark-Field Electron Micrographs of Point Defects and Organometallics

1975 ◽  
Vol 33 ◽  
pp. 200-201
Author(s):  
William Krakow
Keyword(s):  
Electron Micrographs ◽  
Point Defects ◽  
Structure Determination ◽  
Atomic Structure ◽  
Image Interpretation ◽  
Dark Field ◽  
Field Electron ◽  
Dark Field Microscopy ◽  
Dark Field Electron

Tilted beam dark-field microscopy has been applied to atomic structure determination in perfect crystals, several synthesized molecules with heavy atcm markers and in the study of displaced atoms in crystals. Interpretation of this information in terms of atom positions and atom correlations is not straightforward. Therefore, calculated dark-field images can be an invaluable aid in image interpretation.

Imaging sub-micron objects with light microscopy: Visualization of the T-4 bacteriophage

1989 ◽  
Vol 47 ◽  
pp. 834-835
Author(s):  
Malcolm Brown ◽  
Reynolds M. Delgado ◽  
Michael J. Fink
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Focal Plane ◽  
Phase Contrast ◽  
Dark Field ◽  
E Coli ◽  
Polystyrene Beads ◽  
Television Camera ◽  
Transmission Electron ◽  
Universal Microscope

While light microscopy has been used to image sub-micron objects, numerous problems with diffraction-limitations often preclude extraction of useful information. Using conventional dark-field and phase contrast light microscopy coupled with image processing, we have studied the following objects: (a) polystyrene beads (88nm, 264nm, and 557mn); (b) frustules of the diatom, Pleurosigma angulatum, and the T-4 bacteriophage attached to its host, E. coli or free in the medium. Equivalent images of the same areas of polystyrene beads and T-4 bacteriophages were produced using transmission electron microscopy.For light microscopy, we used a Zeiss universal microscope. For phase contrast observations a 100X Neofluar objective (N.A.=1.3) was applied. With dark-field, a 100X planachromat objective (N.A.=1.25) in combination with an ultra-condenser (N.A.=1.25) was employed. An intermediate magnifier (Optivar) was available to conveniently give magnification settings of 1.25, 1.6, and 2.0. The image was projected onto the back focal plane of a film or television camera with a Carl Zeiss Jena 18X Compens ocular.

The Order in Which Antibiotics are Administered Affects the Fitness Costs of Adherent-Invasive E. coli (AIEC) Strains

2019 ◽  
Author(s):  
Jordan B Gregg
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Combination Therapy ◽  
Agar Plate ◽  
Sequential Therapy ◽  
Negative Control ◽  
Clinical Settings ◽  
Fitness Costs ◽  
Inflammatory Gene Expression ◽  
E Coli

AIEC-LF82 is a strain of bacteria that is surmised to have a role in causing IBD and Crohn’s disease by activating pro-inflammatory gene expression in organisms. Using antibiotics via combination therapy has been a technique used in clinical settings in an attempt to treat the strains, however, the attempts have not been that effective nor efficient in terms of completely halting the growth and colonization of AIEC to treat IBD and Crohn's disease patients. Research has shown that regarding hindering or preventing the colonization bacterial colonies, sequential therapy tends to be more effective and time-efficient than combination therapy, with fewer adverse effects. To test if this is also the case with the AIEC-LF82 strain of bacteria, I first tested AIEC’s response to combination therapy using the Penicillin-Streptomycin, Kanamycin-Chloramphenicol, antimicrobial peptide (AMP), Kanamycin, SPE phase and LB agar plates, all of which were experimental plates other than the LB agar plate that acted as the negative control. I then tested AIEC-LF82’s response to sequential therapy using the LB+ Kan + Spe, LB + AMP + Spe, LB+ Kan/Cam + Spe, LB + P/S + Spe, LB + P/S + Kan and LB + P/S + AMP and one LB agar plate acting as the negative control. The only differences between sets a and b were the order in which antibiotics were administered in the six aforementioned treatment sets. Ultimately, I found that set b of sequential therapy, strong-weak antibiotic treatments, was the most effective treatment but that set a regarding sequential therapy was actually the least effective of all of the treatments. In conclusion, using strong-weak sequential antibiotic therapy treatments appears to be a potentially promising option to treat patients suffering from Crohn's disease and IBD.

Isolation and identification of lactic acid bacteria in Bakasang as fermented microbe starter

2013 ◽  
pp. 48
Author(s):  
J Aquarista Ingratubun ◽  
Frans G Ijong ◽  
Hens Onibala
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Pathogenic Bacteria ◽  
Raw Materials ◽  
Fermented Food ◽  
Plate Count ◽  
Local Market ◽  
Bacillus Sp ◽  
Isolation And Identification ◽  
Total Plate Count

Food fermentation is one of various food processing techniques that has sufficient benefits of nutrition values, and also contains lactic acid bacteria which potentially inhibit pathogenic bacteria, thus prolong shelf life of  products. Bakasang is a traditional fermented food from North Sulawesi since many years ago. Reported research of bakasang previously had described that lactic acid bacteria was the dominant isolates and therefore current research  aimed to isolate and identify the lactic acid bacteria which associated during fermentation day 1 and day 15, respectively. Raw materials used were 5 kg intestine and liver of skipjack brought from local market Bersehati Manado. The intestine and liver of skipjack were washed and smashed and mixed with 10% salt  and 5% rice  from weight of the samples and then filled into bottle to be fermented for 15 days. Every 3 days (1,3,6,9,12,15), the samples were collected and analyzed for total lactic acid bacteria by using Total Plate Count Method on de Mann Rogosa Sharpe Agar after incubation at 37°C for 24 h. The colonies  grown were transferred to Tryptic Soy Broth and followed by streaking them on Tryptic Soy Agar and the free growing colony on agar medium were isolated into slant agar which were used for biochemical test such as Gram’s staining, motility test, catalase test, oksidase test, H2S test, IMVIC test (Indole, Methyl Red, Voges Proskauer, Citrate) and carbohydrate fermentation. The results showed that Lactobacillus sp., Bacillus sp., Eubacterium sp., and Bifidobacterium sp. All these four bacteria were distributed from day 1 to day 15 of the fermentation process© Fermentasi bahan pangan merupakan salah satu dari sekian banyak teknik pengolahan makanan yang mempunyai banyak manfaat dari kualitas gizi, mengandung bakteri asam laktat sehingga menghambat bakteri patogen sehingga daya simpan lebih panjang. Bakasang merupakan makanan fermentasi tradisional masyarakat Sulawesi Utara yang sudah ada sejak lama. Penelitian yang telah dilakukan terhadap bakasang menghasilkan informasi bahwa terdapat bakteri asam laktat pada bakasang sehingga menjadi tujuan untuk mengisolasi dan identifikasi bakteri asam laktat selama proses fermentasi 1-15 hari. Bahan baku bakasang ialah jeroan (usus dan hati) ikan cakalang Katsuwonis pelamis sebanyak 5 kg yang diambil dari pasar Bersehati Manado. Sampel jeroan dibersihkan kemudian dihancurkan, ditambahkan garam 10% dan nasi 5% kemudian difermentasi selama 15 hari dengan mengambil tiap-tiap sampel setiap 1, 3, 6, 9, 12, dan 15 untuk dihitung jumlah bakteri asam laktat dengan menggunakkan metode Total Plate Count pada media de Mann Rogosa Sharpe Agar dan koloni yang tumbuh di tumbuhkan  kembali pada media Tryptic Soy Broth  dan digores kembali pada media Tryptic Soy Agar, koloni yang tumbuh digores pada media slant agar yang selanjutnya diidentifikasi bakteri asam laktat berdasarkan uji biokimia yaitu uji pewarnaan Gram, uji motility, uji katalase, uji oksidase, uji H2S dan uji IMVIC (Indole, MethylRed, Voges Proskauer, Citrate). Hasil menunjukkan bahwa selama proses fermentasi berlangsung terdapat 4 genera bakteri asam laktat sesuai yaitu Lactobacillus sp., Bacillus sp., Eubacterium sp., dan Bifidobacterium sp., ke 4 genera ini tersebar pada fermentasi hari 1 sampai hari ke 15©

Sign in / Sign up

Export Citation Format

Share Document