Contact: Wendel Sloan at 505.562.2253
LUBBOCK—Ms. Bonnie Cash, an Eastern undergraduate student, won the second-place award and Mr. Eliseo Castillo, an Eastern graduate student, won the first-place award for their recent presentations at the Student Research Day at Texas Tech University Health Science Center.
Abstracts of their presentations follow:
Cash, B.M. and M.F. Varela (2004) "Orange Oil Confers Multidrug Resistance to Several Commonly Used Antibiotics in Both Gram-negative and Gram-positive Dairy Soil Isolates"
We tested the hypothesis that orange oil, commonly used in household cleaners, modulates antibiotic resistance levels in both Gram-positive and Gram-negative bacteria. Previous studies have shown that bacterial isolates from clinical and agricultural environments can develop multidrug resistance upon exposure to various multiple antibiotic resistance (mar) modulators, such as salycilate (a component of aspirin) and various household cleaners, such as orange oil. Gram-positive bacteria can also be multidrug resistant and have mar-dependent and mar-independent loci, but is it not known to what extent mar (and mar-independent) modulators (i.e., orange oil) affect Gram-positive bacterial antibiotic resistance, thus hindering our understanding of drug resistance mechanisms in such microorganisms. Thus, we examined bacterial antibiotic resistance profiles using E-strips (AB Biodisk) on Mueller-Hinton agar inoculated with Gram-negative agricultural isolates (Escherichia coli, Proteus mirabilis, Citrobacter amalonaticus, Enterobacter sakazakii, and E. taylorae, n=9) and various wild-type Gram-positive bacteria (Bacillus subtilis, B. cereus, Staphylococcus aureus, and Enterococcus faecalis, n=4) in the presence and absence of orange oil, incubating at 37 C overnight and determining the minimal inhibitory concentrations (MICs). Seventy-five and 100 percent of the Gram-negative isolates were highly resistant to tetracycline (MIC >256 g/ml, P <0.001) (7/8 isolates) and ciprofloxacin (>32 g/ml, P<0.0001) (4/4 isolates) upon exposure to undiluted orange oil compared to negative controls (MICs, 13.1 g/ml, 11 ng/ml), respectively. All Gram-positive bacteria became resistant to vancomycin (MIC >256 g/ml, P<0.0001), tetracycline (MIC >256 g/ml, P<0.001) and ciprofloxacin (MIC >32 g/ml, P<0.0001) upon exposure to orange oil compared to negative controls (MIC 3.3 g/ml, 0.6 g/ml, 10 ng/ml), respectively. 5 mM salicylate was used as a positive control, and antibiotic resistance values were comparable to orange oil induction numbers (MIC > 32 g/ml for ciprofloxacin and >256 g/ml for tetracycline). We conclude that orange oil modulates multidrug resistance in both the Gram-negative and Gram-positive bacteria, indicating that the antibiotic resistance mechanisms can be modulated by exposure to orange oil.
Eliseo F. Castillo and Manuel F. Varela (2004) "Computational Evidence for Evolutionary Adaptation of Viral Proteins CMP6L, T1R and R1R to Mimic the Human Z protein, A Member of an Apoptotic Suppressor Family, Bi1"
Viruses have evolved throughout time circumventing the human immune system. The present report describes the evolution of viral proteins, T1R from Cowpox, R1R from Monkeypox and the Camelpox NMDA-receptor like protein (CMP6L), which mimic the human Z protein. The viral proteins above are shown in this report to share conserved amino acid sequences with the human Z protein using multiple sequence alignments and by PSI-Blast search. The Z protein is a member of the Bi1 (Bax inhibitor 1) family according to SwissProt, in which members of this family have function in apoptotic suppression. A phylogenetic tree was built, and it showed that the Z protein is related to a Bi1 protein and the viral proteins are related to the Z protein. This tree was built with 100% certainty which was determined by 100 replicates of bootstrapping. A secondary structural motif was predicted for the viral proteins, Bi1 and the human Z protein by SOSUI, and all were considered membrane proteins. The accuracy of this system, discrimination of membrane proteins, existence of transmembrane helical regions, are about 99%, 96% and 85% respectively (4). The helices of the viral proteins shared conserved amino acids with the Z protein and were identified by multiple sequence alignments. Comparison of pI, hydropathicity, molecular weight and hydrophobicity by ProtParam revealed that the proteins shared similar protein characteristics. Thus, the multiple sequence alignments, phylogenetic tree, structural motif's and the protein characteristics generated from the biological computational tools collectively suggest and allow us to speculate that CMP6L, T1R and R1R share a common evolutionary origin and that they have evolved to function as suppressors of apoptosis.