Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

Rhodococcus equi is a soil-dwelling facultative intracellular pathogen that can infect many mammals, including humans. R. equi is most well known for its ability to cause severe pyogranulomatous disease in foals, primarily involving the lungs although other body systems may also be affected. The disease is endemic on many horse-breeding farms worldwide and poses a severe threat to the horse breeding industry because there is no vaccine available. Current prophylaxis is based on systematic preventative treatments with macrolides combined with rifampicin, which are also used to treat clinical cases of the disease in foals. In this thesis I have used a combination of wet laboratory and bioinformatic approaches to identify the molecular basis of emerging combined resistance to macrolides and rifampicin in R. equi foal isolates from the USA. The genomes of a selection of resistant and susceptible strains from across the USA were sequenced and assembled. Resistance genes were systematically searched by reciprocal best-match BLASTP comparisons to known antibiotic resistance determinants. This led to the discovery of a novel erythromycin ribosomal methylase (erm) gene, erm(46), in all resistant strains. Complementation analysis in a susceptible R. equi strain showed that erm(46) was sufficient to confer resistance to all macrolides, lincosamides, and streptogramin B. The erm(46) gene is carried by an integrative conjugative element (ICE) which is transferable between R. equi strains. The ICE is formed by two distinct parts, a class I integron associated with an IS6100 sequence and the erm(46) determinant carried by a sub-element which contains putative actinobacterial conjugative translocase apparatus and a transposase/integrase. All resistant strains also carry the same non synonymous point mutation in rpoB conferring rifampicin resistance. Thus, these strains are carrying double resistance to the most commonly used antibiotics to treat R. equi worldwide. Phylogenetic analysis based on the core genome demonstrated that all resistant strains are clonal. This indicates that although conjugal acquisition of the erm(46) conjugative element may occur at a high frequency, the need for the concurrent presence of a second rpoB mutation for survival in the macrolide and rifampicin dominated farm environment has effectively selected for the spread of a single clone. In the second section of this work, we sequenced a further 20 R. equi genomes from difference sources (equine, porcine, bovine, human), including representatives of each of the seven major genogroups previously defined in our laboratory based on pulsed field gel electrophoresis. I have used the newly acquired genetic information to study the genome of R. equi and analyse its diversity within and outwith its species group. This enabled us to explore the pan genome and define that R. equi is a genetically well-defined bacterial species. Our results provide definitive evidence that resolves the current dispute over R. equi classification, specifically they do not support the recent proposal (based on classical polyphasic bacterial taxonomical methods) that R. equi should be transferred to a new genus. Our core-genome phylogenomic analyses unambiguously show that the genus Rhodocococcus is monophyletic and that R. equi forms a clade together with the most recently described related environmental species R. defluvii that radiates from within the genus. Together with other shared biological and genetic characteristics, namely the unique niche-adaptive mechanism based on evolutionarily related extrachromosomal replicons, R. equi should be conseidered a bona fide member of the genus Rhodococcus. We also confirm that Rhodococcus spp. and Nocardia spp. are sufficiently distinct to warrant them belonging to different genera. In conclusion, this work used whole genome sequencing to characterize the molecular basis underlying the emergence and clonal spread of multi-resistant R. equi in horse breeding farms in the USA. This work also highlights the limitations of classical taxonomical approaches in bacterial systematics, and illustrates the importance of incorporating modern phylogenomic approaches to understand the evolutionary relationships between bacterial strains and their accurate taxonomic position.

Chai, Stella. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 108-126). / Abstracts in English and Chinese. / ABSTRACT --- p.i / 論文摘要 --- p.iii / ACKNOWLEDGEMENTS --- p.v / PATENT AND PUBLICAION --- p.vii / CONFERENCE ABSTRACTS AND PRESENTATIONS --- p.viii / AWARDS --- p.ix / ABBREVIATIONS --- p.x / LIST OF TABLES --- p.xii / LIST OF FIGURES --- p.xiv / TABLE OF CONTENT --- p.xviii / Chapter CHAPTER 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Multidrug resistance (MDR) --- p.1 / Chapter 1.1.1 --- Cancer --- p.1 / Chapter 1.1.2 --- Mechanisms of MDR in cancer --- p.1 / Chapter 1.1.2.1 --- Drug entry --- p.3 / Chapter 1.1.2.2 --- Drug metabolism --- p.3 / Chapter 1.1.2.3 --- Drug sequestration --- p.4 / Chapter 1.1.2.4 --- Mechanisms activated after nuclear entry --- p.5 / Chapter 1.1.2.5 --- Evasion of drug-induced apoptosis --- p.5 / Chapter 1.1.3 --- Approaches in treating MDR --- p.5 / Chapter 1.1.3.1 --- Overcoming MDR by inhibiting transporters --- p.6 / Chapter 1.1.3.2 --- Overcoming MDR by altering signaling pathway --- p.6 / Chapter 1.1.4 --- ATP Binding Cassette (ABC) Transporters --- p.7 / Chapter 1.1.4.1 --- P-glycoprotein (P-gp) --- p.7 / Chapter 1.1.4.2 --- Multidrug resistance-associated protein 1 (MRP 1) --- p.9 / Chapter 1.1.4.3 --- Breast cancer resistant protein (BCRP) --- p.10 / Chapter 1.1.4.4 --- ABC drug transporters and drug absorption --- p.11 / Chapter 1.2 --- The Use of Traditional Chinese Medicine (TCM) in circumventing P-gp-mediated MDR --- p.12 / Chapter 1.2.1 --- Active ingredients in TCM - Alkaloid --- p.12 / Chapter 1.2.2 --- Active ingredients in TCM - Saponin --- p.14 / Chapter 1.2.3 --- Active ingredients in TCM - Flavonoid --- p.15 / Chapter 1.2.4 --- Active ingredients in TCM - Others --- p.17 / Chapter 1.3 --- Polyoxypregnane compounds (POPs) --- p.17 / Chapter 1.3.1 --- Characterization --- p.17 / Chapter 1.3.2 --- POPs isolated from M. tenacissima --- p.18 / Chapter 1.4 --- Objectives of Current Study --- p.22 / Chapter CHAPTER 2. --- EFFECTS OF POLYOXYPREGNANE COMPOUNDS ON VIABILITY AND PROLIFERATION OF HUMAN RESISTANT CANCER CELLS --- p.24 / Chapter 2.1 --- Materials and Methods --- p.25 / Chapter 2.1.1 --- "Chemicals, Materials and Reagents" --- p.25 / Chapter 2.1.2 --- Methods --- p.26 / Chapter 2.1.2.1 --- Cell Lines and Cell Culture --- p.26 / Chapter 2.1.2.2 --- Preparation of POPs --- p.27 / Chapter 2.1.2.3 --- Sulforhodamine B assay --- p.27 / Chapter 2.1.2.4 --- Statistical analysis --- p.29 / Chapter 2.2 --- Results --- p.29 / Chapter 2.2.1 --- Effects of POPs on the viability of parental SW620 and P-gp-overexpressing resistant SW620/Ad300 cells --- p.29 / Chapter 2.2.2 --- Effects of POPs on the viability of parental MCF-7 and MRP1-overexpressing resistant MCF-7/VP cells --- p.33 / Chapter 2.2.3 --- Effects of POPs on the viability of parental MCF-7 and ABCG2-overexpressing resistant MCF-7/FLV1000 cells --- p.37 / Chapter 2.3 --- Discussion --- p.41 / Chapter 2.3.1 --- Structure activity relationship (SAR) --- p.43 / Chapter 2.3.2 --- Nine compounds relating to P-gp-mediated MDR --- p.46 / Chapter CHAPTER 3. --- MECHANISM OF NINE SELECTED POPS IN MODULATING P-GP-MEDIATED MDR --- p.49 / Chapter 3.1 --- Materials and Methods --- p.49 / Chapter 3.1.1 --- "Chemicals, Materials and Reagents" --- p.49 / Chapter 3.1.2 --- Methods --- p.53 / Chapter 3.1.2.1 --- Cell Lines and Cell Culture --- p.53 / Chapter 3.1.2.2 --- Extraction of nine POPs from M. tenacissima --- p.54 / Chapter 3.1.2.3 --- Sulforhodamine B (SRB) assay --- p.55 / Chapter 3.1.2.4 --- Flow cytometry assay --- p.55 / Chapter 3.1.2.5 --- P-gp ATPase assay --- p.56 / Chapter 3.1.2.6 --- Immuno-blot/Western blot analysis --- p.58 / Chapter 3.1.2.7 --- Reverse transcription and quantitative real-time PCR --- p.59 / Chapter 3.1.2.8 --- Statistical analysis --- p.60 / Chapter 3.2 --- Results --- p.60 / Chapter 3.2.1 --- Effects of nine selected POPs on the viability of sensitive human breast cancer MCF-7 cells --- p.60 / Chapter 3.2.2 --- Effects of nine selected POPs on the viability of MDR 1 -transfected HEK1 MDR1 cell line and its control vector transfected cell line HEK293 pcDNA3 --- p.61 / Chapter 3.2.3 --- Effects of nine selected POPs in inhibiting efflux of P-gp substrate --- p.64 / Chapter 3.2.4 --- Effects of nine selected POPs in modulating P-gp ATPase activity --- p.68 / Chapter 3.2.5 --- Effects of nine selected POPs in regulating P-gp protein expression --- p.69 / Chapter 3.2.6 --- MDR1 mRNA expression in various cell lines --- p.72 / Chapter 3.3 --- Discussion --- p.72 / Chapter 3.3.1 --- Effective POPs are targeting specifically P-gp overexpression --- p.73 / Chapter 3.3.2 --- Mechanistic understanding the circumvention of MDR by the effective POPs --- p.74 / Chapter 3.3.2.1 --- Relative potency for the reversal of P-gp-mediated MDR --- p.75 / Chapter 3.3.2.2 --- Inhibition of P-gp-mediated drug efflux across cell membrane by the effective POPs --- p.75 / Chapter 3.3.2.3 --- Stimulation of ATPase by the effective POPs --- p.76 / Chapter 3.3.2.4 --- No effect of POPs on the alteration of P-gp expression --- p.77 / Chapter 3.3.2.5 --- An overall summary of the mechanism of MDR reversal by the effective POPs --- p.78 / Chapter 3.3.3 --- Implication in drug disposition and drug-drug interactions --- p.79 / Chapter 3.3.4 --- Additional information for the structure activity relationship (SAR) --- p.80 / Chapter CHAPTER 4. --- EFFECTS OF CRUDE EXTRACT AND THREE MAJOR POLYOXYPREGNANES (POPS) OF MARS DEN I A TENACISSIMA --- p.81 / Chapter 4.1 --- Materials and Methods --- p.82 / Chapter 4.1.1 --- "Chemicals, Materials and Reagents" --- p.82 / Chapter 4.1.2 --- Methods --- p.82 / Chapter 4.1.2.1 --- "Preparation of M. tenacissima extract, artificial mixture and three fractions" --- p.82 / Chapter 4.1.2.2 --- Sulforhodamine B assay --- p.85 / Chapter 4.1.2.3 --- "Biotransformation study of POP68, POP69 and POP70" --- p.85 / Chapter 4.1.2.4 --- HPLC-MS analysis --- p.86 / Chapter 4.1.2.5 --- Animal care and housing conditions --- p.87 / Chapter 4.1.2.6 --- Toxicity studies of fraction 2 in mice --- p.88 / Chapter 4.1.2.7 --- Statistical analysis --- p.89 / Chapter 4.2 --- Results --- p.89 / Chapter 4.2.1 --- "Effects of crude extract, artificial mixture on the viability of sensitive human breast cancer MCF-7 cells" --- p.89 / Chapter 4.2.2 --- "Effects of crude extract, artificial mixture on the viability of sensitive SW620 and P-gp-overexpressing resistant SW620/Ad300 cells" --- p.90 / Chapter 4.2.3 --- "Metabolites of POP68, POP69 and POP70 after incubation with human intestinal microbiota" --- p.91 / Chapter 4.2.4 --- Toxicity of fraction 2 in mice --- p.94 / Chapter 4.3 --- Discussion --- p.98 / Chapter CHAPTER 5. --- FINAL DISCUSSION AND CONCLUSIONS --- p.105 / REFERENCES --- p.108

Master of Science / The role of the microbiology laboratory is (1) to provide infection control information, so that highly transmissible isolates may be identified and appropriate control measures instigated as rapidly as possible and (2) to provide adequate information to the clinician enabling correct antibiotic choices to be made, particularly in the critically ill. Microbiological data is by definition slow as it is culture dependent: this study focused on the development of genetic, culture-independent methods for detection of resistance in nosocomial pathogens that could be introduced into the routine microbiology department and would fit into the routine workflow with a consequent reduction in time to result. Initially a duplex real-time polymerase chain reaction was developed for the rapid identification and detection of S. aureus and methicillin-resistance. This was optimised for immediate as-needs testing of positive blood cultures signalling with “Gram positive cocci, possibly staphylococcus” evident on Gram stain, on a random access real-time PCR platform. This technology, allowing early identification of S. aureus and its susceptibility to methicillin, by simple automated methodology, may soon become the standard for all microbiology laboratories servicing the critically ill. The second part of the study involved the development of a selective broth and multiplex PCR for detection of three important nosocomial isolates at this institution, methicillin-resistant S. aureus (MRSA), carbapenem-resistant Enterobacteriaceae, and multi-resistant Acinetobacter baumannii (MRAB). A multiplex PCR using four primer sets was designed to detect low colonisation levels of these isolates after overnight incubation in selective broth, significantly reducing the time to result and associated costs. This potentially useful epidemiological screening tool is practical, reproducible and sensitive with the potential of moving to an automated test (using real-time PCR, for example) in the future. The availability of early negative results judged by simple visual scanning (or by densitometry), means that the result is less operator-dependent, potentially reducing error rate. The last part of the study dealt with an important resistance phenotype, aminoglycoside resistance. There had been no recent comprehensive local surveys performed to determine the frequency of aminoglycoside resistance amongst the Enterobacteriaceae, or to identify the genetic determinants and their transmissibility. The isolates collected for the study were all resistant to at least one of gentamicin, tobramycin or amikacin. Identification of integron cassette arrays and use of specific internal primers identified at least one genetic determinant for gentamicin and tobramycin resistance in 22 of 23 isolates. Three isolates had two aminoglycoside resistance genes, and three isolates had three aminoglycoside resistance genes identified (Table 6.1). Transferable gentamicin-resistant plasmids were predominant amongst Klebsiella spp., but less so amongst Enterobacter spp. and E. coli. Gentamicin-resistant Klebsiella spp. were often ESBL positive, the genetic determinants of which were typically co-transferred on a conjugative plasmid. The importance of screening at a local level was demonstrated by the unexpected predominance of aac(6')-IIc amongst Enterobacter spp. and the detection of a new gene (aac(6')-LT). This part of the study has provided an understanding of the primary aminoglycoside resistance genes present in the local setting and their association with other resistances. This knowledge will allow development of assays for patient screening (clinical isolates and colonising flora), to better understand the epidemiology of aminoglycoside resistance and to allow better choice of antibiotic therapy related to presence or absence of these genes.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Background: In mobile phone industry, Smartphones are gaining popularity as an effective communication tool, providing users with “Smart” functionalities of both cell-phone and Personal Digital Assistant (PDA). Experts in mobile industry expect that smartphones are going to be dominant in mobile phone market. However, Smartphone industry is facing a different reality, with its declining sales and less market share, forcing research companies (Gartner, Canalys, etc.) to change their expectations. This situation leads us to another important and often ignored perspective of innovation challenges, i.e. consumers' resistance; as consumers' adoption and purchase decision makes a significant difference in the success of innovative products. Problem: Innovation has been called as a key factor for companies to survive and grow in the long run, especially in the dynamic & complex markets and uncertain economic circumstances. Despite the successful outcome of innovations, inhibition or delay in the diffusion of innovation may translate this success into market failure, where resistance has been called as one of the main reasons for inhibiting or delaying the innovation diffusion. Consumers adoption of innovation depend upon several factors: the most important of which are specified as consumers’ characteristics (psychological characteristics of consumers; how they view the innovativeness with respect to that particular product), and the innovation characteristics (outcome and effects of innovation). Past research on innovation & consumers characteristics represents good relationship among the innovation/consumers factors and the adoption/implementation of that innovation by consumers. Purpose: The purpose of this study is to identify and analyze the relationship between consumers' resistance and different factors from innovation and consumers' characteristics. Thereafter, important factors are identified that mainly affect/determine consumers' resistance to smartphones. Moreover, the inter-relationship (correlation) among the selected factors is found out, to know the affects of each factor on other factors. Method: Following abductive approach, confirmatory factor analysis has been done on pre-test questionnaires to test, improve, and verify the constructs (variables/questions) for measuring the hypothesized factors. A theoretical model has been proposed from the hypotheses; and Structural Equation Modeling has been applied, where results are estimated through Partial Least Square and AMOS approaches, using a sample of 330 respondents from Sweden. SmartPLS software has been used to estimate results, thereafter, AMOS has been used to check and verify the results. Almost same results have been derived from both approaches, while results from PLS are found as more satisfactory. Conclusions: Five out of eight hypotheses have been supported by our empirical data, where H1 i.e. relative advantage, H3 i.e. complexity, and H4 i.e. perceived risk, are from innovation characteristics, while H6 i.e. motivation, and H7 i.e. „favorable attitude towards existing products‟ are from consumers' characteristics. Motivation, Complexity, Relative Advantage, and Perceived Risk are found as important factors (as per their order) that affect/determine consumers' resistance to smartphones. Relative Advantage & Motivation are found as positively correlated, and Perceived Risk & Complexity are found as positively correlated. Negative correlation has been found between Perceived Risk and relative advantage. Similarly, negative correlation has been found between motivation and complexity. The proposed model of consumers resistance to smartphones shows an acceptable goodness of fit, where 65% (R-square value) of variation in consumers resistance is caused/explained by the hypothesized factors. / The Presentation (Defense) has been attended by Cecilia Bjursel instead of our supervisor Desalegn Abraha.

The ubiquitous nature of antibiotic resistance and antibiotic resistance genes (ARGs) among environmental pathogens from a variety of wastewater effluents, suggests that the aquatic environment, and specifically alternative wastewater treatment systems, may act as reservoirs for drug resistant bacteria and ARGs, thereby contributing to the widespread dissemination of antibiotic resistance. More research is necessary to contribute to our understanding of the occurrence, fate, and mobility of antibiotic resistance and ARGs among bacterial indicators of faecal contamination as well as pathogenic bacteria within Canadian wastewater treatment systems. The primary objective of this research was to determine the prevalence, fate, and potential transfer of bacterial resistance and ARGs among selected environmental pathogens exposed to alternative wastewater treatment systems, while considering the impact of treatment strategies on the expression of antibiotic resistance. A detailed analysis was initially conducted with respect to the characterization and quantification of microbial populations (including antibiotic resistant bacteria) in a variety of treatment systems and waste effluent sources. Traditional culture-based screening techniques in combination with molecular characterization (through colony or multiplex PCR), and molecular quantification using real-time quantitative PCR were utilized in order to help establish a preliminary environmental assessment of selected pathogens (Escherichia coli, Enterococcus spp., Salmonella spp.) and ARGs (tetA, blaSHV, & ampC) within a variety of wastewater treatment systems (lab-scale mesocosms, constructed wetland, constructed lagoon system, and pilot-scale biological nutrient removal (BNR) system). Overall, the level of multiple antibiotic resistance (MAR) among culturable indicator (E. coli & Enterococcus spp.) and environmental bacteria was high (reaching 100% in several instances) within different types of wastewater treatment systems and effluent sources (poultry waste effluent, municipal wastewater, aquaculture wastewater). Common antibiotic resistance profiles among E. coli isolates included simultaneous resistance to between three and five antimicrobials, whereas common MAR profiles among Enterococcus spp. isolates showed resistance to ten or more antibiotics. Real time quantitative PCR was used to determine the concentration of three bacterial pathogens; E. coli, Enterococcus faecalis, and Salmonella spp., and three ARGs; tetA, ampC, and blaSHV, within a variety of wastewater samples. Based on the results, it was concluded that high concentrations of ARGs were present in the treated effluent (10⁴- 10⁶ target gene copies/100 mL), regardless of system type (i.e. constructed lagoon, pilot-scale BNR, or constructed wetland), which may ultimately serve as a potential route for entry of ARGs and antibiotic resistant bacteria into the natural environment. Water is considered an important medium for transfer of resistance genes and resistant bacteria to the broader environment. Few studies have examined the transferability via conjugation of ARGs in E. coli and Salmonella spp. isolated from wastewater. Identification of three resistance determinants (tetA, strA, strB) conferring resistance to tetracycline and streptomycin was performed on selected multi-drug resistant Salmonella spp. and E. coli isolates. The potential for transfer of tetracycline and streptomycin resistance genes was demonstrated through broth conjugation experiments using multi-drug resistant Salmonella spp. and E. coli isolates as donors, and E. coli K12 as the recipient. Conjugation was successfully observed in 75% (9/12) of donor isolates, occurring in both Salmonella spp. and E. coli isolates. Six strains (50%) were capable of transferring their tetA, strA, and strB genes to the recipient strain, resulting in 58.5% (38/65) of total transconjugant strains acquiring all three resistance determinants. The results confirm the role of environmental bacteria (isolated from wastewater treatment utilities) as a reservoir of antibiotic resistance and ARGs, containing mobile genetic elements, which are capable of disseminating and transferring ARGs. As concerns about water quality and environmental contamination by human and agricultural effluents have increased, it has become increasingly more important to consider the prevalence and transferability of ARGs to opportunistic and human pathogens. As observed in this research, the ubiquitous nature of multi-drug resistant bacteria in water and wastewater effluents, the presence of diverse ARGs of human and veterinary health significance, as well as the transfer of resistance determinants through conjugative plasmids to recipient bacteria, suggests that environmental exposure through contact or consumption with contaminated water is probable. However, a lack of critical information still exists regarding the movement of resistance genes within and between microbial populations in the environment. In addition, the extent of human exposure to ARGs and antibiotic resistant bacteria is still not well understood, and future studies on human exposure to these resistant contaminants are necessary.

The effect of thermo-mechanical processing by deformation and annealing on the grain boundary configuration of commercially pure Ni-200 is reported in this thesis. Ni-200 is unalloyed, thus avoiding the complex effects associated with alloying elements on the formation and development of different types of grain boundaries. One step strain-recovery with strain levels in the range of 3% to 7.5% (with 1.5% intervals) and annealing temperatures in the range of 800ºC to 1000ºC (with 100ºC intervals) were used in processing. The effects of parameters such as strain level, annealing temperature, annealing time and grain growth on grain boundary configurations were studied. Using Orientation Image Microscopy (OIM) it was found that the Fsp (fraction of special grain boundaries) value of strained samples annealed in the range of 800ºC to 1000ºC began to increase after a critical length of time, after which the Fsp value increased quickly and becoming a maximum in 2~4 minutes. The length of the critical annealing time for the increase of Fsp was shorter in the material with the higher levels of strain at a constant annealing temperature. Also the critical annealing time was shorter when annealed at higher temperatures under a fixed level of strain. The Fsp value increased to 80% from an as received value of about 30% in the samples with varying strain levels. However, the Fsp values only increased from 30% to 45% in the material without strain. Due to grain boundary migration, the Fsp values increased with grain size and became a maximum during the heat treatment of the strained material. In the material without strain however even when grain growth occurred, limited improvement in Fsp values occurred showing that contribution of strain is very important to the formation of special boundaries. By varying the strain levels, annealing temperatures and times, material with high Fsp values in a wide range of grain size can be obtained. Under the present processing conditions used however, multi-cycle was not helpful to the improvement of Fsp. TEM observations indicated dislocation tangles occurred near the grain boundary of the 1x6% strained samples. These dislocation tangles decreased with time at 800˚C and were reduced considerably after 20 minutes. Thermodynamic and kinetic models were used in the calculations of twin density-grain size relationships. The results indicated that the contribution of strain is equivalent to the increase of grain boundary energy, which provided an extra driving force and improved probability of twin embryo formation. / February 2009

A combination of root morphology and plant physiology with drought/or salt tolerance should affect drought resistance in cotton (Gossypium hirsutum L.). This experiment was developed to evaluate early vegetative and seedling growth of cotton from the unselected parents with two selected populations of M-8844-0100, DPL 50, and TAM 94L-25 across two cycles for seedling drought. Three genotypes from three generations of selection were grown in tubes to evaluate early growth and in containers to evaluate seedlings for drought resistance in a greenhouse at College Station, TX in 2008 and 2009. The experiment during the winter months of 2008 resulted in shorter tap root length, fewer lateral roots, and lower fresh and dry weight for total root, lateral roots, and shoots. The drought selections in these genotypes affected the tap root fresh weight, and the number and weight of lateral roots. TAM 94L-25 averaged higher tap root fresh and dry weight, lateral root fresh weight and shoot fresh weight. DPL 50 exhibited greater weight of lateral roots and shoot fresh weight. No difference was found in percent wilting across generations for drought at 75 percent apparent wilting and recovery at 90 percent apparent wilting.