Thesis (Ph.D.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 117 pages. Includes Vita. Includes bibliographical references.

Specific Drosphila tRNA Ser4,7 plasmids were identified and isolated by hybridization with purified [¹²⁵I] tRNA Ser4,7 molecules. Seven clones were isolated carrying the Drosphila Ser tRNA Ser4,7 gene and were further characterized by restriction endonuclease digestion; agarose gel electrophoresis and hybridization with individual purified [¹²⁵I] tRNA Ser4,7 molecules. The results show that five different DNA fragments have been isolated, four which code for a single, specific isoacceptor, and one which appears to code for two different isoacceptors. Two plasmids which initially contained multiple Hind III inserts upon primary isolation were recloned to contain single Hind III inserts containing the tRNA Ser4,7 gene. One of these recloned plasmids contained a smaller tRNA Ser4,7 gene carrying insert than did its original multiple insert isolate. Small tRNA Ser4,7 gene carrying restriction fragments were labelled with T4 polynucleotide kinase and [³²P] ATP, strand separated, and electroeluted, in preparation for nucleotide sequencing. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

The complete nucleotide sequence of the region encoding the DHCDH function of the pDK1 lower operon was determined. DNA analysis has shown the presence of two open reading frames, one gene consisting of 777 nucleotides encoding a polypeptide of 27.85 kDa and another gene of 303 nucleotides encoding a polypeptide of 11.13 kDa. The results of enzymatic expression studies suggest that DHCDH activity is associated only with xy1L. However although the addition of xy1T cell-free extracts to xy1L cell-free extracts does not produce an increase in DHCDH activity, subclones carrying both xy1L and xy1T exhibit 300- 400% more DHCDH activity than subclones carrying only xy1L.

Rhodococcus, a species of bacteria commonly found in the soil, is a under-explored producer of small bioactive compounds including siderophores, pigments and antibiotics.. MTM3W5.2 is a strain of Rhodococcus that was previously discovered to produce an antibiotic-like compound that has inhibitory effects on other Rhodococcus strains, including the veterinary pathogen, R. equi. The biosynthetic gene cluster responsible for production of the antibiotic has been identified, and a small gene, BTZ20_3964 at the start of the operon is believed to be the regulator of the gene cluster. To test this, a deletion construct was created using an overlap-extension PCR method to remove most of gene 3964. The deletion construct was cloned into the plasmid pEX18Km, along with a kanamycin resistance marker. The deletion construct, pEX18Km3964AD was transformed into competent MTM3W5.2 cells for a double crossover recombination event to replace the functional gene with the deletion construct, using the KanR gene to select for the merodiploids, and the SacB gene to select for the deletion mutants after the second recombination event. The deletion mutant’s ability to produce the inhibitory compound will be determined. Production of the compound will be restored by complementing the deletion mutant with the functional gene cloned into the expression plasmid pDD57.

A dissertation submitted to the Faculty of Medicine, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science (medicine).' Johannesburg 1996 / Fifty-two strains of Haemophilus ducreyi from various geographic regions of southern Africa (Botswana, Lesotho, Namibia, Gauteng, Natal and Transkei) isolated between 1988 to 1994 were tested for susceptibilities to five antimicrobial agents and characterized according to their plasmid content and ampicillin- resistance genes. / IT2019

No description available.

Enterococcus faecalis is a Gram-positive bacterial species that is typically a member of the human gastrointestinal tract microbiota. However, E. faecalis is also a nosocomial pathogen, which is involved in urinary tract infections, soft tissue infections and endocarditis. In recent times, the occurrence of antibiotic resistance has complicated the treatment of these infections. One of the major differences between commensal and pathogenic strains of E. faecalis is that pathogens contain multiple mobile elements such as plasmids, transposons and integrative conjugative elements (ICE). These elements allow for the acquisition and transfer of virulence factors and resistance genes. Conjugative plasmids are a class of plasmids present in E. faecalis whose transfer to host cells is induced by a small pheromone peptide, cCF10 (LVTLVFV). This peptide is initially encoded as a 22-amino acid precursor (pre-cCF10) from the signal sequence of the chromosomal ccfA gene and is then proteolytically cleaved by signal peptidase II and Eep. Once pCF10 has been transferred a host E. faecalis cell, it is exceptionally stable. A replicon clone is maintained in greater than 85% of host cells over 100 generations in the absence of selection, suggesting the stability of pCF10 is intrinsic to the replicon. Three unique features of the replication initiation protein PrgW may contribute to this stability: (a) the interaction of PrgW with pre-cCF10, (b) disulfide bond formation at three conserved cysteines (C78, C275, and C307) in PrgW, and (c) processing of the nascent PrgW protein. Replication initiation proteins associated with theta replicons, such as pCF10, are often self-contained units. To initiate plasmid replication, the replication initiation protein (PrgW) binds to direct repeats (oriV) in its own coding sequence (prgW). In silico analysis of PrgW suggests the existence of three distinct domains within the protein. The first 122 amino acids are homologous to a conserved domain present in related replication initiation proteins, which includes a Helix-Turn-Helix (HTH) DNA binding domain. This suggests that this domain of PrgW has a DNA-binding function and binds to the oriV site in prgW. The following 61 amino acids are not similar to any known sequence, and are encoded by the DNA sequence containing the direct repeats in the oriV site. This domain may or may not have a distinct function. The remaining sequence forms a domain that contains cysteines C275 and C307, and is also similar to no known structure. It is hypothesized that this domain is related to the stability of pCF10. C307 appears to be critical, as previous experiments indicate that its mutation alone affects plasmid stability. Secondary structure analysis of this domain revealed the presence of multiple alpha-helices that contain distinct hydrophobic domains that possibly contribute to pre-cCF10 binding and PrgW tertiary structure. The positions of the conserved cysteines within these alpha-helices may stabilize a hydrophobic binding pocket that could potentially facilitate interaction with pre-cCF10. PrgW has a predicted molecular weight of 38.6 KDa and can be detected in Western blots as a band with an apparent approximate molecular weight (mw) of 36,000. Previous data from our lab indicates that, when overexpressed in E. faecalis, four bands of PrgW are present with observed molecular weights of 40,000, 36,000, 24,000 and 18,000. Time course experiments revealed that the 40,000 mw form is converted to a 36,000 mw form independent. The 40,000 mw form is unstable (with a complete turnover in 30 minutes) while the 36,000 mw form has a half-life of greater than 4 hours. The 24,000 mw band does not have a DNA binding motif and is likely a turnover product. When the three conserved cysteines (and only cysteines) in PrgW are replaced with alanine, the 40,000 mw form is still processed to the 36,000 mw form. However, the cysteine to alanine mutants accumulate the 36,000 mw form. / Microbiology and Immunology

The gluconobacters are well known for their plasma membrane-bound dehydrogenases that rapidly oxidize compounds and release the products into the medium. In 1989, Qazi et al. proposed that genes coding for membranebound glucose dehydrogenase are on a plasmid in G. oxydans strain ATCC 9937. The only other known report of gluconobacter plasmids was by Fukaya, et al. who reported that 23 of 36 strains examined contained plasmids. I wish to learn more about the presence and significance of plasmids in the gluconobacters. In this study, I selected 14 strains representing the three gluconobacter species to determine possible similarities and differences in their plasmid profiles. To date, our most successful method for extracting plasmids involves alkaline lysis of cells at 60°C followed by phenol-chloroform extraction which leaves the nucleic acids in the aqueous phase. These nucleic acids are then precipitated in a LiCl-ethanol solution using glycogen as a carrier, and plasmids are separated on agarose gels. We found that 11 of the 14 gluconobacter strains surveyed contain plasmids ranging in size from 2.7 to greater than 200 kb. The type strain of the genus (G. oxydans strain ATCC 19357) contained 6 plasmids ranging in size from 4 to 120 kb. Strains from G. frateurii and G. asaii also contained a wide range of plasmid sizes. Hybridization techniques were utilized to determine if plasmids of similar size are genetically similar. The 2.7 and 16.2 kb plasmids of G. oxydans strain ATCC 621 and IFO 12528 were shown to share homology. The 100 and 120 kb plasmids of G. oxydans strain ATCC 19357 hybridized with the 250 kb plasmids of ATCC 621 and the 210 kb plasmid of ATCC 9937. Also showing homology were the 6.4 kb plasmids of G. oxydans strains ATCC 9937 and IFO 12467. / Master of Science

A virulent Mycobacterium avium strain, LR25, which carries 3 plasmids (18, 28, and 165 kb) and grows at 43°C was compared to its plasmid-free, avirulent segregant, strain LR163, to investigate the basis for the latter's inability to grow at 43°C. The failure of mid-log phase cultures of strain LR163 to grow at 43°C was dependent upon the presence of high levels of culture aeration. In addition, highly aerated mid-log phase cultures of strain LR163 failed to grow at 379C, By contrast, late-log phase cultures of strain LR163 were capable of growth when shifted to 43°9C under highly aerobie conditions. Mid-log phase cells of strain LR163 had 30% of the catalase activity of mid-log phase cells of strain LR25 and were more susceptible to hydrogen peroxide (0.08% w/v). Catalase activities of late-log, early-stationary, and stationary phase cells of strain LR163 were Significantly higher than mid-log phase cells. Catalase activity of strain LR25 was highest in cells of mid-log phase cultures, whereas the catalase activity of strain LR163 was highest in cells of stationary phase cultures. These data support the idea that plasmid-encoded genes influence M. avium catalase activity. / Master of Science

Thesis (PhD (Microbiology))--University of Stellenbosch 2010. / ENGLISH ABSTRACT: Two isogenic plasmids, pRAS3.1 (11,851-bp) and pRAS3.2 (11,823-bp), were identified as tetracycline resistance plasmids occurring within Aeromonas salmonicida subsp. salmonicida and atypical A. salmonicida subsp. salmonicida strains that were isolated from salmon aquaculture farms in Norway (L'Abee-Lund and Sorum, 2002). Although sequence analysis showed that, except for the repC gene, the replication and mobilization genes of the two pRAS3 plasmids are similar to that of the two IncQ-2 plasmids pTF-FC2 and pTC-F14, incompatibility testing during the course of this study revealed that the replicons of the two pRAS3 plasmids were compatible with the replicons of the IncQ-1α, ß] and y plasmids RSF1010, pIE1107 and pIE1130, as well as with the IncQ-2α and ß plasmids, pTF-FC2 and pTC-F14, respectively. Through sequence analysis it was suggested that the repC gene of the ancestral pRAS3 plasmid was probably acquired during a gene exchange event with a yet to be identified plasmid. The difference in the RepC of the pRAS3 plasmids compared to that of the other IncQ-like plasmids against which the pRAS3 plasmids were tested for incompatibility was thus suggested to be a likely reason for the compatibility of the two pRAS3 plasmid replicons with these IncQ-1 and IncQ-2 plasmids. Two previously unidentified genes, encoding two small 108 and 74-aa proteins distantly related to the PemIK (Bravo et al., 1987; Tsuchimoto et al., 1988) and MazEF (Masuda et al., 1993) TA systems, were found to be present between repB and repA genes of the two pRAS3 plasmids. Cloning of these two genes onto an unstable pOU82-test vector increased the stability of the vector from 35 to 98% after ~72 generations, thus suggesting that like the PasABC and PasAB systems of pTF-FC2 and pTC-F14, these two genes encode proteins which function as a toxin-antitoxin (TA) system. Although located in a similar position on the plasmids, the TA system of the two pRAS3 plasmids and the Pas systems of pTF-FC2 and pTC-F14 are unrelated, suggesting that these two types of TA systems were acquired independently from each other. Based on the sequence similarity and genetic organization of pRAS3 compared to the IncQ-2α and ß] plasmids pTF-FC2 and pTC-F14, respectively, but given that the pRAS3 plasmids were compatible with both pTF-FC2 and pTC-F14, as well as other IncQ-like plasmids, it was suggested that the two pRAS3 plasmids be classified into a new IncQ-2y subgroup. A comparison of the sequences of the two pRAS3 plasmids to each other by L'Abee-Lund and Sorum (2002) revealed that, apart from a number of point mutations within the tetAR tetracycline resistance genes of the two plasmids, the only other differences between them are that pRAS3.1 has 4 tandem copies of 22-bp iteron repeats within its origin of vegetative replication (oriV), and 5 tandem copies of CCCCCG 6-bp repeats near the origin of transfer (oriT), while pRAS3.2 has only three and four copies of each of the two repeated sequences, respectively. As the two pRAS3 plasmids are likely to have arisen from the same ancestor, this raised the question of how the copy numbers of these two different types of repeat sequences affected the ability of pRAS3.1 and pRAS3.2 plasmids to compete within a host cell as well as within a population of host cells, and therefore, why both of these isogenic plasmids have managed to persist in the environment. The plasmid copy numbers (PCN) of pRAS3.1 and pRAS3.2 were estimated to be 45 ± 13 and 30 ± 5 plasmids per chromosome, respectively. By creating a series of pRAS3.1 derivative plasmids with 3 to 7 copies of the 22-bp iterons and 4 or 5 copies of the 6-bp repeats, it was shown that an increase in the number of iterons brought about a decrease in PCN, probably due to an increased ability to bind RepC, while an increase in the number of 6-bp repeats from 4 to 5 brought about an increase in repB transcription, and the higher levels of RepB resulted in an increase in PCN. Thus the reason for pRAS3.1 having a ~1.5-fold higher PCN than pRAS3.2, even though it has 4 x 22-bp iterons compared to the 3 x 22-bp iterons of pRAS3.2, was that it had a higher level of repB transcription due to having 5 x 6-bp repeats in its mobB-mobA/repB promoter region compared to the 4 x 6-bp repeats of pRAS3.2. The differences in the number of iterons and 6-bp repeats, and hence PCN, did not have an effect on the stability of the two wild type (WT) plasmids or their derivatives even when the TA system was neutralized by having a copy of the TA genes present on a vector in trans and it was argued that the relatively high PCN of the two pRAS3 plasmids was sufficient to ensure plasmid stability through random distribution. As the two pRAS3 plasmids were mobilized at similar frequencies difference in PCN and mobB-mobA/repB transcription did not seem to affect their mobilization frequency. When pRAS3.1 and pRAS3.2 were competed intracellularly as coresident plasmids, pRAS3.1 was able to displace pRAS3.2 from 98% of the host cells within ~20 generations. The displacement of pRAS3.2 by pRAS3.1 was found to be as a result of pRAS3.1 having 4 x 22-bp iterons, which enabled pRAS3.1 to titrate of the communal pool of available RepC initiator proteins. Plasmids with 5 or 7 x 22-bp iterons, were however less effective at displacing a plasmid with 3 iterons, and it was speculated that plasmids with more than 4 x 22-bp iterons within their oriV were less successful at initiating replication than was a plasmid with 3 iterons within its oriV. A direct correlation was found between the PCN of a pRAS3 plasmid and the metabolic burden it imposed on its host. Thus pRAS3.1, as a result of its ~1.5-fold higher PCN than pRAS3.2 placed a small but significantly higher (~2.8%) metabolic load on its host compared to pRAS3.2. It was concluded that pRAS3.1 had a competitive advantage over pRAS3.2 when these plasmids were coresident within a single host (as would have been when the two plasmids first diverged from each other) as it was able to displace pRAS3.2. However, as a result of pRAS3.2 having a lower PCN, it placed a smaller metabolic burden on an isogenic host and this resulted in pRAS3.2 having an advantage over pRAS3.1 at the population level. Sequence remnants of pRAS3.2 from horizontal gene transfer suggested that pRAS3.2 was the original pRAS3 plasmid and thus that pRAS3.1 evolved from pRAS3.2. As the pRAS3.1 derivative plasmids that were constructed during the course of this study are likely to have been intermediates in the evolution of pRAS3.1 from pRAS3.2, I was able to speculate on the stepwise evolution of pRAS3.1 from pRAS3.2 based on the characteristics of these plasmids, and thus, how both macro- and microevolutionary events have contributed to the evolution of these two plasmids. / AFRIKAANSE OPSOMMING: Die twee isogeniese plasmiede, pRAS3.1 en pRAS3.2, was geidentifiseer as tetrasiklien weerstandbiedende plasmiede wat in Aeromonas salmonicida subsp. salmonicida en nie-tipiese A. salmonicida voorkom (L'Abee-Lund and Sorum, 2002). DNS volgorde analise deur L'Abee-Lund en Sorum (2002) het gewys dat die gene verantwoordelik vir replisering (uitsluitend die repC) en mobililisering naverwant is aan die van twee IncQ-2 plasmiede, pTF-FC2 en pTC-F14. Eksperimente tydens hierdie studie het egter gewys dat die repliserende sisteme van die twee pRAS3 plasmiede versoenbaar is met die repliserende sisteme van die IncQ-1α, ß and y plasmiede RSF1010, pIE1107 en pIE1130, sowel as die IncQ-2α en ß plasmiede, pTF-FC2 and pTC-F14, onderskeidelik. Analise van die aminosuur volgorde van die pRAS3 RepC proteien het gedui daarop dat die proteien taamlik verskil van die RepC proteiene van die naverwante plasmiede pTF-FC2 en pTC-F14, sowel as die van die IncQ-1 tipe plasmiede, en daar was voorgestel dat die voorsaat pRAS3 plasmied moontlik die repC geen bekom het vanaf 'n ander, nog onbekende, plasmied deur middel van horisontale geen uitruiling. Die verskil in die RepC van die pRAS3 plasmiede teenoor die van die ander IncQ plasmiede waarteen hulle getoets was vir onversoenbaarheid, was waarskynlik die rede waarom die pRAS3 plasmiede versoenbaar was met die IncQ-1 en IncQ-2 plasmiede. DNS volgorde analise tydens hierdie studie het die teenwoordigheid van twee, vantevore ongeidentifiseerde, klein 108 en 74 aminosuur proteiene onthul wat ver langs verwant is aan die PemIK (Bravo et al., 1987; Tsuchimoto et al., 1988) en MazEF (Masuda et al., 1993) toksien-antitoksien sisteme. Die gene wat kodeer vir hierdie toksien-antitoksien proteine kom tussen die repB en die repA gene van die twee pRAS3 plasmiede voor. Klonering van die toksien-antitoksien gene van die pRAS3 plasmiede op 'n ander onstabiele plasmied het die stabiliteit van hierdie plasmied verhoog van 35 tot en met 98% na ~72 generasies. Hierdie experiment het dus bevestig dat, soos die PasABC en PasAB sisteme van pTF-FC2 en pTC-F14 onderskeidelik, die twee gene 'n toksien-antitoksien sisteem kodeer wat die stabiliteit van 'n plasmied binne 'n bakteriese populasie kan verbeter. Alhoewel die toksien-antitoksien gene van pRAS3 op 'n soortgelyke posisie op die pRAS3 plasmiede voorkom as wat die pasABC en pasAB gene op hulle onderskeidelike pTF-FC2 en pTC-F14 plasmiede voorkom, is hulle nie verwant nie en dus was dit voorgestel dat die twee tipe toksien-antitoksien sisteme onafhanklik van mekaar verkry is. Aangesien die DNS volgorde en genetiese rangskikking van pRAS3 teenoor die IncQ-2α en ß plasmiede pTF-FC2 en pTC-F14, onderskeidelik, soortgelyk is, asook die feit dat die pRAS3 plasmiede versoenbaar was met pTF-FC2 en pTC-F14, sowel as ander IncQ tipe plasmiede, word dit voorgestel dat die twee pRAS3 plasmiede in 'n nuwe IncQ-2y subgroep ingedeel word. 'n Vergelyking van die DNS volgorde van die twee pRAS3 plasmiede deur L'Abee-Lund and Sorum (2002) het gewys dat, behalwe vir 'n paar puntmutasies binne die tetAR tetrasiklien weerstandsgene, verskil die twee net in die opsig dat pRAS3.1 het 4 agtereenvolgende kopiee van 22-bp 'iteron' herhalings wat gelee is binne sy replikasie oorsprong en 5 kopiee van 'n CCCCCG 6-bp herhaling wat naby sy oorsprong van oordrag gelee is, terwyl pRAS3.2 net 3 en 4 kopiee het van elk van die onderskeie volgorde herhalings. Dus die bestaan van twee plasmiede met verskillende kopiegetalle van die twee verskillende tipe DNA volgorde herhalings, maar wat vermoedelik afkomstig is vanaf dieselfde stam plasmied, bring die volgende oorhoofse vrae aangaande die plasmiede na vore: hoe beinvloed die DNS volgorde herhalings die vermoe van die twee plasmiede om binne 'n enkele gasheersel te kompeteer vir die beskikbare plasmied repliserings masjinerie, en hoe beinvloed dit die plasmied-gasheersel verhouding en dus hulle vermoe om te kompeteer op die populasie vlak, en laastens, hoekom het beide weergawes van die plasmied bly voortbestaan in die omgewing? Die plasmied kopiegetalle van pRAS3.1 en pRAS3.2 was eksperimenteel beraam by ongeveer 45 ± 13 en 30 ± 5 plasmiede per chromosoom in E. coli, onderskeidelik. Deur 'n reeks van pRAS3.1 derivate te skep met 3 tot 7 'iteron' herhalings en 4 of 5 kopiee van die 6-bp herhalings was dit bewys dat 'n toename in die hoeveelheid 'iterons' 'n afname in die plasmied kopiegetal veroorsaak, vermoedelik deur 'n verbeterde vermoe om RepC te bind, terwyl 'n verhoging van 4 tot 5 kopiee van die 6-bp herhaling 'n afname in die kopiegetal te weeg gebring het. Die repB geen van 'n plasmied met 5 x 6-bp herhalings was ~2-voud hoer uitgedruk as die van 'n plasmied met 4 x 6-bp herhalings, en dit was verder bewys dat 'n verhoogde vlak van repB transkripsie vanaf 'n L-arabinose induseerbare promoter in trans van 'n pRAS3 plasmied met 4 x 6-bp herhalings het 'n ~2-voud verhoging in plasmied kopiegetal teweeg gebring. Die rede dat pRAS3.1 'n ~1.5-voud hoer plasmied kopiegetal gehad het as pRAS3.2, was as gevolg van 'n hoer vlak van repB uitdrukking weens die feit dat pRAS3.1 5 x 6-bp herhalings in die mobB-mobA/repB promoter area het terwyl pRAS3.2 net 4 van die 6-bp herhalings in dieslefde posisie het. Sou pRAS3.1 4 x 22-bp 'iterons' gehad het, maar saam met 4 x 6-bp herhalings soos pRAS3.2, dan sou die plasmied kopiegetal 23 ± 2 plasmiede per chromosoom gewees het. Die verskil in die hoeveelheid 'iterons' en 6-bp herhalings, en dus die plasmied kopiegetal, het nie 'n effek op die stabiliteit van die wilde tipe plasmiede of hulle derivate gehad nie, selfs al was die toksien-antitoksien sisteem geneutraliseer deurdat daar 'n kopie van die toksien-antitoksien sisteem op 'n ander plasmied in trans van die pRAS3 plasmiede en hul derivate geplaas was. Die relatiewe hoe plasmied kopiegetal van die pRAS3 plasmiede, wat moontlik hoog genoeg was om plasmied stabiliteit deur middel van toevallige uitdeling te verseker, was voorgestel as die rede vir die hoe mate van plasmied stabiliteit. Soortgelyke frekwensies van mobilisasie vir pRAS3.1 en pRAS3.2 (0.032 ± 0.014 en 0.021 ± 0.013 transkonjugate per donateur, onderskeidelik) was waargeneem. Dus het dit geblyk dat die verskil in uitdrukking van die mobB-mobA/repB operon, sowel as die plasmied kopiegetal van die twee pRAS3 plasmiede, nie die mobiliserings frekwensie beinvloed het nie. Intrasellulere kompetisie tussen pRAS3.1 en pRAS3.2 het gewys dat pRAS3.1 die vermoe gehad om binne ~20 generasies pRAS3.2 vanuit 98% van die gasheerselle te skop. Daar was gewys dat die teenwoordigheid van 4 x 22-bp 'iterons' in die oorsprong van replikasie van pRAS3.1 die rede was vir die vermoe van hierdie plasmied om pRAS3.2 uit te kompeteer binne die gasheersel, moontlik deurdat die 4 x 22-bp 'iterons' beter in staat was om die RepC protein te bind. Die vermoe van plasmiede met 5 of 7 x 22-bp 'iterons' om te kompeteer met 'n plasmied met net 3 x 22-bp 'iterons' was toenemend swakker in vergelyking met die van 'n plasmied met 4 x 22-bp 'iterons', en hierdie waarneming het gelei tot die voorstel dat plasmiede met meer as 4 x 22-bp 'iterons' nie so suksesvol was om replikasie te inisieer soos ¡¥n plasmied met 3 x 22-bp 'iterons' nie. 'n Direkte korrelasie was gevind tussen die plasmied kopiegetal van 'n pRAS3 plasmied en die metaboliese lading wat die plasmied op die gasheersel geplaas het. Dus het pRAS3.1, met 'n plasmied kopiegetal van ~1.5-voud hoer as die van pRAS3.2, 'n effens hoer (~2.8%) metababoliese lading op die gasheersel as pRAS3.2 geplaas. In gevolge van die inter- en intrasellulere kompetiesie eksperimente, was dit ge-argumenteer dat pRAS3.1 'n mededingende voordeel bo-oor pRAS3.2 binne 'n gasheersel (soos wat dit sou gewees het kort nadat die twee plasmiede van mekaar uiteengevloei het) gehad het omdat dit in staat was om pRAS3.2 vanuit die gasheersel te skop. Aan die ander kant het pRAS3.2 'n laer plasmied kopiegetal en dus 'n laer metaboliese lading op die isogeniese gasheersel geplaas het, en daardeur het pRAS3.2 weer op die populasievlak die kompeterende voordeel bo-oor pRAS3.1 gehad. Die eienskappe van pRAS3.2 was meer soortgelyk aan die van ander IncQ-tipe plasmiede as wat die eienskappe van pRAS3.1 was, en dus word dit voorgestel dat pRAS3.1 vanaf pRAS3.2 afkomstig was. Omdat die derivaat plasmiede wat geskep was vanaf pRAS3.1 tydens hierdie studie moontlike tussengangers in die ontwikkeling van pRAS3.1 vanaf pRAS3.2 was, kan gespekuleer word, gebaseer op die eienskappe van hierdie plasmiede, oor die “stapsgewyse manier” waarmee pRAS3.1 vanaf pRAS3.2 ge-evolueer het, en dus hoe beide makro- en mikro-evolusionere gebeurlikhede bygedra het tot die evolusie van genoemde plasmiede.