Browsing by Subject "Microorganisms"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item An in vitro evaluation of a Pseudomonas Syringae pv. Tagetis strain as a potential biocontrol agent(Texas Tech University, 1997-12) Krieg, AndreaThe potential of SL Pseudomonas syringae pv. tageris Tox strain to provide control of the Tox* strain was tested using competition as a basis for comparison. Initially, growth curves of individual strains in both complex and defined media were developed In the complex medium 523, the Tox strain did exhibit greater growth than the other two strains tested and was significantly greater at two points during the assay. In all othCT media tested, the growth of the three strains was almost identical. Ratios of the Tox to Tox*/Rif strains -1:1 and 3:1, WCTC then tested in minimal salts (defined) and 523 (complex) media. In the defined medium, the ratio began and ended at the same point, either 1:1 or 3:1. In the complex medium, only the 1:1 ratio was tested and this ended in a 4:1 ratio in favor of the Tox strain. The 3:1 ratio as well as individual strains were then tested using sunflowCT leaf disks. The Tox and Tox*/Rif strains alone grew much faster than the Tox' strain in the ratio, while the Tox^/Rif strain grew almost as well as it did inoculated as a single strain. The ratio behaved in contradiction of the behavior obsoved in culture. The Tox strain seemed to be inhibited in the ratio and the data taken at 48 hours was 1:5 in fiavor of the Tox*/Rif strain. While still contradicting the results obtained in culture media, the whde plant assay did not follow the same pattern as that seen in the leaf disk assay. At 24 hours, the ratio between the Tox and Tox^/Rif strains which began at 3:1, had shnmk to a little more than 1:1. Data taken at 48 hours showed that the Tox^/Rif strain's population had outgrown that of the Tox' strain reversing the ratio to 1:1.4. From the data presented, it can not be concluded that the Tox strain is capable of providing any measure of biological control of the Tox*/Rif strain.Item Biological growth on the Alamo(2009-05) Gallagher, Casey Amber; Gale, Frances R.The limestone façade of the Alamo shows several areas of biological growth with black and gray streaks and blotches discoloring the stone. This thesis investigates the identity of the microorganisms on the stone, using two: DNA identification, and lab cultures grown from samples of the biofilm. By using both approaches, a better understanding was gained of the range of organisms present. Through these tests, it was found that the dominant organism on the limestone is cyanobacteria, of the genus Chrooccocus. Lab cultures revealed other organisms, including possibly fungi photobionts and algae. Through analysis and comparison of historic and contemporary photographs, patterns of recolonization are investigated. To further understand the effects of the biocide treatments, cultured samples were treated, and their reactions monitored. To better understand the possible relationship between the Alamo stone and its colonizing organisms, physical properties of the stone were investigated. SEM images, Edax minerology and water absorption were used to characterize the stone. This study is the first of its kind to investigate Native Texas quarried architectural limestone. Although studies have been conducted on historic monuments around the world to identify biological growth, none have focused on Texas limestone. By using both DNA and lab culture identification, this study adds to a wealth of investigations of other conservation professionals, applying it to a subject that has not been studied in this way before. By understanding the colonizing organisms, a sustainable conservation regimen can be determined.Item Chill and trim effects on the microbial load of pork carcasses(Texas Tech University, 1995-12) Carr, Mandy AnnettIn a two-part study, composited ham, loin, belly and shoulder samples from 30 pork carcasses in a 2 X 2 X 3 factorial study (hot-fat trim - HFT or nonfat trim - NFT X normal chill - NC or freeze chill - FC X day) had similar aerobic plate counts, averaging 5.5 log-,o CFU/g. The NFTNC procedure typically used in the industry, however, produced higher coliform and Staphylococcus spp. counts (P < .05). The HFTFC treatment had the lowest lactic acid bacteria (LAB) counts. Only one sample in 60 tested positive for Salmonella. Vacuum packaged hams and loins stored at 4°C for 14 d had similar ARC, LAB and Staphylococcus spp. counts regardless of trim, chill, or location treatment, averaging 5.7, 6.3 and 1.4 log^o CFU/g, respectively. Coliforms were higher (P < .05) on hams than loins on 2 of the 3 d sampled. The desire to reduce microbial loads on pork carcasses as a food safety issue and the coming implementation of HACCP warrants the use of trim and chill methods as critical control points or GMP/SOPs in the pork slaughter, processing and packaging industry.Item Isolation of microorganisms from biological specimens by dielectrophoresis(2014-05) D'amico, Lorenzo; Gascoyne, Peter R. C.; Bankson, James A.Every environment of the biosphere supports a particular mix of microorganisms called a microbiome. These diverse microbial communities play critical roles in the health of ecosystems and in higher organisms, including humans. Disruption or translocation of microbiomes may cause lethal infections, contaminate food and drug supplies, and adversely impact industrial activities. Microbiome detection and molecular characterization have emerged as priorities in many fields. Available methods cannot quickly and efficiently extract rare microorganisms in real specimens. Therefore, microbial detection and analysis require long incubation periods or the use of technically challenging molecular biotechnologies. These strategies are impractical in situations requiring immediate intervention. The intrinsic electric and dielectric properties of microbes permit their isolation by the phenomenon of dielectrophoresis in microfluidic devices. These microsystems have the potential to enhance microbial analysis but are plagued by low processing rates and the inability to interface with biological specimens containing high levels of interfering cells and debris. In this study, a method was created to discriminate between target microbes and undesired cells on the basis of their differential susceptibility to permeabilizing agents that altered cell dielectrophoretic responses. Fabrication techniques were developed to manufacture high-aspect ratio microfluidic channels that allowed the physical forces of gravity, diffusion and dielectrophoresis to be exploited to control cell positions over microscale distances normal to a Poiseuille flow gradient. Because the positioning effects were exploited in only one dimension, the other two dimensions of the channels could be scaled up to create large channel cross-sectional areas that supported rapid specimen processing rates while maintaining high separation efficiencies expected for the microscale effects. These strategies were applied in various ways to isolate microbes from whole blood, platelets, stool, saliva, and skin specimens. The dielectrophoretic extraction of microbes enabled by this approach was used to enable electrical impedance detection of ~100 bacteria in less than five hours. As a result, important technological barriers that have limited the applicability of dielectrophoresis in clinical and industrial settings were overcome by increasing throughput and addressing sample preparation requirements. These proof-of-concept data demonstrate the potential for accelerating microbial isolation and detection in diagnostics, screening, and microbiome research.Item The evaluation of selected organisms for use in the conversion of mesquite to single cell proteins(Texas Tech University, 1971-12) Key, Alan BradleyNot available