Endoscopy-assisted dacryocystorhinostomy in a dog.

OBJECTIVE: To describe the use of an endoscope to assist in performing minimally invasive dacryocystorhinostomy in a dog to successfully manage a nasolacrimal duct cyst (dacryocyst). ANIMAL STUDIED: A 4-year-old female spayed American Staffordshire Terrier with chronic epiphora and swelling ventromedial to the nasal canthus of the right eye and reverse sneezing. PROCEDURES: Computed tomography revealed a fluid-filled cystic lesion of the right nasolacrimal duct with extensive nasal extension and secondary obstructive frontal sinusitis. Aspiration of serosanguinous fluid with no growth of microbial organisms and histopathology confirmed the cystic nature of the structure. A 2.7 mm, 30 deg, 11 cm foreward-oblique endoscope with arthroscopic cannula was passed through a mucosal stab incision in the dorsal buccal recess into the cyst to allow for exploration. A separate instrument portal was placed in the center of the cyst through the skin which allowed for transcutaneous dacryocystorhinostomy with a meniscal probe to be performed. No clear communication was evident caudodorsally into the frontal sinus on endoscope examination. A small frontal sinus trephination was performed and lavage flowed easily into the cystic cavity and out of the nostril. RESULTS: Follow-up at 10 days and 17 months postoperatively showed complete resolution of clinical signs with an excellent cosmetic outcome. CONCLUSION: Endoscopy-assisted dacryocystorhinostomy demonstrated an effective minimally invasive technique to treat a functionally obstructive dacryocyst of the right nasolacrimal duct in a dog.

Engaging Undergraduate Nursing Students in Collaborative Research.

BACKGROUND: Nurses are expected to base practice on evidence from research, which requires an understanding of the research process. However, baccalaureate nursing students may find research courses uninteresting or feel unprepared to conduct research. Participation in experiential research projects may affect their research attitudes, knowledge, and skills. METHOD: Nursing investigators engaged nursing students in an experiential, active learning research project centered on the effects of pet interaction involving university students. Faculty mentored and partnered with nursing students, immersing them in all research processes. RESULTS: Students confirmed that participation in the project enhanced their understanding of research, improved their clinical and communication skills, and fostered professional growth. Students presented results in a scientific poster at the University's research event. CONCLUSION: Collaborative faculty-student research projects enhance students' interest in and appreciation of evidence-based research, and support professional development, confidence in assuming research roles, and feelings of connection with faculty, each other, and the university. [J Nurs Educ. 2024;63(X):XXX-XXX.].

First report of Phytophthora infestans lineage EU23 causing potato and tomato late blight in South Africa.

In South Africa, potato (Solanum tuberosum) late blight epidemics from 1996 to 2007 were caused by Phytophthora infestans clonal lineage US-1 (McLeod et al. 2001; Pule et al. 2013). Similarly, surveys on tomatoes in the mid-1990s only identified the US-1 clonal lineage in South Africa (McLeod et al., 2001). On potatoes, populations from the Southern Cape and Western Cape regions consisted of persistent mefenoxam-resistant populations (McLeod et al. 2001; Pule et al. 2013). Limited mefenoxam (R-enantiomer of metalaxyl) screening in 2021 in the Western Cape showed that potato isolates were sensitive, which prompted our study. Potato late blight samples were collected in 13 potato fields in the 2021 to 2023 seasons in the Western Cape (n = 4), Free State (n = 7), Limpopo (n = 1) and Kwazulu-Natal (n = 1) Provinces, and one tomato sample in 2022 in the Limpopo Province. Fourteen samples, one per field, were simple sequence repeat (SSR) genotyped for 12 loci (Li et al. 2013) using as DNA template, FTA cards, or genomic DNA extracted from cultures. P. infestans isolations from lesions and DNA culture extractions were conducted as previously described (Pule et al. 2013). SSR genotyping revealed that all 14 P. infestans samples belonged to clonal lineage EU_23_A1 (EU23), which has a phenotype (A1 and metalaxyl sensitive) and SSR genotype matching the US-23 lineage (Saville et al., 2021). As expected, minor polymorphisms were detected among the samples at loci Pi02, G11, D13 and SSR4. Mefenoxam sensitivity testing of seven potato isolates from the Free State (n = 3) and Western Cape (n = 4), and one tomato isolate was conducted as previously described (Mcleod et al. 2001). All isolates were sensitive to mefenoxam since no infection and sporulation occurred at 3 µg/ml. This was expected since EU23 has been reported as mefenoxam sensitive in other countries (Kawchuk et al., 2011; McGrath et al., 2015). Replacement of the US-1 clonal lineage by EU23 suggests that the latter lineage is more aggressive or fit than US-1, but this must be verified especially on potatoes. On tomatoes, on the other hand, EU23 is known as a highly aggressive lineage (Kawchuk et al., 2011; McGrath et al., 2015; Saville et al., 2021). Therefore, population displacements may have first occurred on tomatoes from where the lineage spread to potatoes. In the Cape coastal potato production regions, population displacement may have been supported by the withdrawal of mefenoxam/metalaxyl from the region since 1996 because the EU23 lineage is mefenoxam sensitive, as opposed to the previously prevailing US-1 mefenoxam-resistant lineage. More severe potato late blight epidemics has not been observed in recent years in South Africa. However, tomato late blight has increased and is more prevalent in the Limpopo province. The source of the introduction of EU23 into South Africa is unknown. Only test-tube plants and/or greenhouse tubers may be imported into South Africa since 1997. Therefore, the illegal importation of planting material may have introduced the new genotype. Whether this could have occurred from neighbouring African countries is unknown since P. infestans genotyping has not been conducted in these countries. In Africa, EU23 has been reported in northern African countries (Tunisia, Algeria and Egypt) (Saville et al., 2021; El-Ganainy et al., 2023). Mefenoxam and metalaxyl applications will likely be effective again in the Western Cape, but more samples will have to be tested to confirm this. This will provide growers with a more cost-effective fungicide (metalaxyl) since alternative actives with comparable systemic and curative activity are more expensive.

Case report: Atlantoaxial instability and subluxation in a dog with Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome is a rare, heritable connective tissue disorder characterized by soft, hyperextensible skin, joint hypermobility, and tissue fragility, the severity of which can range from mild to severe. A 9-month-old male entire miniature Dachshund was presented following peracute tetraparesis. Neurological examination was suggestive of intracranial vestibular disease or high cervical myelopathy. MRI revealed atlantoaxial instability and subluxation, resulting in marked spinal cord compression at C1-C2, which was surgically stabilized. On discharge from the hospital, skin fragility was noted as the result of skin tearing during tape removal. A piece of full-thickness antebrachial skin was submitted for histopathology which showed changes consistent with Ehlers-Danlos syndrome. This case report describes the first case of atlantoaxial instability and subluxation in a dog as the result of a confirmed underlying collagenopathy.

Treatment of canine cutaneous epitheliotropic T-cell lymphoma with oclacitinib: a case report.

Canine cutaneous epitheliotropic T-cell lymphoma (CETL) is associated with a poor prognosis and without consistently beneficial treatment options. This case report describes a 9-year-old Staffordshire bull terrier with CETL treated with oclacitinib (0.7 mg/kg twice daily), resulting in partial remission that was maintained for three months. Further studies are warranted.

Le lymphome cutané T épithéliotrope canin (CETL) est associé à un pronostic faible et sans option thérapeutique bénéfique constante. Ce cas clinique décrit un Staffordshire bull-terrier de 9 ans avec CETL traité avec oclacitinib (0,7 mg/kg deux fois par jour), résultant en une rémission partielle qui s'est maintenue trois mois. Des études supplémentaires sont nécessaires.

El linfoma epiteliotrópico cutáneo de células T canino (CETL) se asocia con un mal pronóstico y sin opciones de tratamiento consistentemente beneficiosas. Este informe de caso describe un Staffordshire bull terrier de 9 años con CETL tratado con oclacitinib (0,7 mg/kg dos veces al día), lo que resultó en una remisión parcial que se mantuvo durante tres meses. Se necesitan más estudios.

O linfoma epiteliotrópico canino de células T (CETL) está associado a um mau prognóstico e sem opções de tratamento consistentemente benéficas. Este relato de caso descreve um Staffordshire bull terrier de 9 anos de idade com CETL tratado com oclacitinib (0,7 mg/kg duas vezes ao dia), resultando em remissão parcial que foi mantida por três meses. Mais estudos são necessários.

Mouth Care in Assisted Living: Potential Areas for Improvement.

BACKGROUND: Poor oral care may lead to systemic disease, and there is evidence that assisted living (AL) residents lack quality oral care; in AL, poor care may be due to staff knowledge and attitudes, as well as organizational barriers to providing care. OBJECTIVES: Determine AL staff knowledge and attitudes regarding mouth care and barriers to changing care. DESIGN: Self-administered repeated-measures questionnaires completed before and after oral care training. SETTING AND PARTICIPANTS: A total of 2012 direct care staff and administrators from 180 AL communities. METHODS: Nine knowledge questions and 8 attitude and practice intention questions, and open-ended questions regarding training and obstacles to providing oral care. RESULTS: Overall, 2012 participants completed pretraining questionnaires, and 1977 completed posttraining questionnaires. Baseline knowledge was high, but staff were not uniformly aware of the systemic-oral link whereby mouth care affects pneumonia and diabetes. Almost all staff reported learning a new technique (96%), including for residents who resist care (95%). Suggested areas to improve mouth care included having more hands-on experience. The primary perceived obstacles to care centered around residents who resist care and a lack of time. CONCLUSIONS AND IMPLICATIONS: Based on reports of having benefitted from training, AL staff overwhelmingly noted that new knowledge was helpful, suggesting the benefit of skills-based training, especially in dementia care. Mouth care in AL has been sorely understudied, and merits additional attention.

Diagnosis and Multimodal Treatment of Metastatic Maxillofacial Juvenile Embryonal Rhabdomyosarcoma in a Young Golden Retriever.

A 2 yr old male castrated golden retriever was evaluated for a rapidly progressing maxillofacial spindle cell tumor. On examination, an ill-defined left maxillary mass, a 2 cm swelling under the left eye, and an enlarged left mandibular lymph node were noted. The dog was bright and alert but appeared painful upon jaw extension. Cytology from the lymph node revealed metastatic disease. Thoracic radiographs and computed tomography scan revealed pulmonary nodules. Computed tomography of the head and neck revealed a 6.7 × 4.1 × 6.5 cm mass at the rostral aspect of the left zygomatic arch invading the orbit. A second opinion of the biopsy specimen in conjunction with positive immunohistochemical staining for desmin led to a revised diagnosis of rhabdomyosarcoma. Treatment consisted of three doses of palliative radiation therapy, in 8 Gy fractions, and chemotherapy with vincristine, cyclophosphamide, and doxorubicin. A rapid clinical response was noted shortly after treatment initiation; however, the response was temporary, and the dog was euthanized due to widespread metastatic disease and associated clinical signs 74 days after initial therapy. This is one of the first reports describing positive results from multimodal treatment with chemotherapy and radiation therapy of a maxillofacial juvenile rhabdomyosarcoma in the veterinary literature.

Towards Changing the Long Term Care (LTC) Paradigm: Explicating the Concept of Thriving in Older Adults Living in LTC.

A phenomenon of interest for nursing is the facilitation of humanistic health care experiences and quality of life (Willis, Grace, & Roy, 2008 ). Inquiry into the concept of thriving as it manifests in the older adult residing in long-term care aligns with this interest. Thriving has been described by scholars in various disciplines but no context-specific definition for the LTC resident currently exists. Contrary to the generally held negative view of LTC, there is emerging evidence that older adult LTC residents "do well" or thrive in this environment.

Suppression of human alloreactive T cells by linear tetrapyrroles; relevance for transplantation.

The main limitation to successful transplantation is the antigraft response developed by the recipient immune system, and the adverse side effects of immunosuppressive agents which are associated with significant toxicity and counter indications such as infection and cancer. Furthermore, immunosuppressants do little to prevent ischemia-reperfusion injury during the transplantation procedure itself hence there is a growing need to develop novel immunosuppressive drugs specifically aimed at prolonging graft survival. Linear tetrapyrroles derived from the breakdown of mammalian heme have been shown in numerous studies to play a protective role in allograft transplantation and ischemia-reperfusion injury; however, commercial sources of these products have not been approved for use in humans. Plants and algae produce equivalent linear tetrapyrroles called bilins that serve as chromophores in light-sensing. One such marine-derived tetrapyrrole, phycocyanobilin (PCB), shows significant structural similarity to mammalian biliverdin (BV) and may prove to be a safer alternative for use in the clinic if it can exert direct effects on human immune cells. Using a mixed lymphocyte reaction, we quantified the allogeneic responses of recipient cells to donor cells and found that PCB, like BV, effectively suppressed proliferation and proinflammatory cytokine production. In addition, we found that BV and PCB can directly downregulate the proinflammatory responses of both innate dendritic cells and adaptive T cells. We therefore propose that PCB may be an effective therapeutic drug in the clinical setting of transplantation and may also have wider applications in regulating inappropriate inflammation.

Archaeal community diversity and abundance changes along a natural salinity gradient in estuarine sediments.

Archaea are widespread in marine sediments, but their occurrence and relationship with natural salinity gradients in estuarine sediments is not well understood. This study investigated the abundance and diversity of Archaea in sediments at three sites [Brightlingsea (BR), Alresford (AR) and Hythe (HY)] along the Colne Estuary, using quantitative real-time PCR (qPCR) of 16S rRNA genes, DNA hybridization, Archaea 16S rRNA and mcrA gene phylogenetic analyses. Total archaeal 16S rRNA abundance in sediments were higher in the low-salinity brackish sediments from HY (2-8 × 10(7) 16S rRNA gene copies cm(-3)) than the high-salinity marine sites from BR and AR (2 × 10(4)-2 × 10(7) and 4 × 10(6)-2 × 10(7) 16S rRNA gene copies cm(-3), respectively), although as a proportion of the total prokaryotes Archaea were higher at BR than at AR or HY. Phylogenetic analysis showed that members of the 'Bathyarchaeota' (MCG), Thaumarchaeota and methanogenic Euryarchaeota were the dominant groups of Archaea. The composition of Thaumarchaeota varied with salinity, as only 'marine' group I.1a was present in marine sediments (BR). Methanogen 16S rRNA genes from low-salinity sediments at HY were dominated by acetotrophic Methanosaeta and putatively hydrogentrophic Methanomicrobiales, whereas the marine site (BR) was dominated by mcrA genes belonging to methylotrophic Methanococcoides, versatile Methanosarcina and methanotrophic ANME-2a. Overall, the results indicate that salinity and associated factors play a role in controlling diversity and distribution of Archaea in estuarine sediments.

Survival of Desulfotomaculum spores from estuarine sediments after serial autoclaving and high-temperature exposure.

Bacterial spores are widespread in marine sediments, including those of thermophilic, sulphate-reducing bacteria, which have a high minimum growth temperature making it unlikely that they grow in situ. These Desulfotomaculum spp. are thought to be from hot environments and are distributed by ocean currents. Their cells and spores upper temperature limit for survival is unknown, as is whether they can survive repeated high-temperature exposure that might occur in hydrothermal systems. This was investigated by incubating estuarine sediments significantly above (40-80 °C) maximum in situ temperatures (∼ 23 °C), and with and without prior triple autoclaving. Sulphate reduction occurred at 40-60 °C and at 60 °C was unaffected by autoclaving. Desulfotomaculum sp. C1A60 was isolated and was most closely related to the thermophilic D. kuznetsovii(T) (∼ 96% 16S rRNA gene sequence identity). Cultures of Desulfotomaculum sp. C1A60, D. kuznetsovii(T)and D. geothermicum B2T survived triple autoclaving while other related Desulfotomaculum spp. did not, although they did survive pasteurisation. Desulfotomaculum sp. C1A60 and D. kuznetsovii cultures also survived more extreme autoclaving (C1A60, 130 °C for 15 min; D. kuznetsovii, 135 °C for 15 min, maximum of 154 °C reached) and high-temperature conditions in an oil bath (C1A60, 130° for 30 min, D. kuznetsovii 140 °C for 15 min). Desulfotomaculum sp. C1A60 with either spores or predominantly vegetative cells demonstrated that surviving triple autoclaving was due to spores. Spores also had very high culturability compared with vegetative cells (∼ 30 × higher). Combined extreme temperature survival and high culturability of some thermophilic Desulfotomaculum spp. make them very effective colonisers of hot environments, which is consistent with their presence in subsurface geothermal waters and petroleum reservoirs.

Gastric digestion of α-lactalbumin in adult human subjects using capsule endoscopy and nasogastric tube sampling.

In the present study, structural changes in the milk protein α-lactalbumin (α-LA) and its proteolysis were investigated for the potential formation of protein-fatty acid complexes during in vivo gastric digestion. Capsule endoscopy allowed visualisation of the digestion of the test drinks, with nasogastric tubes allowing sampling of the gastric contents. A total of ten healthy volunteers had nasogastric tubes inserted into the stomach and ingested test drinks containing 50 g/l of sucrose and 25 g/l of α-LA with and without 4 g/l of oleic acid (OA). The samples of gastric contents were collected for analysis at 3 min intervals. The results revealed a rapid decrease in the pH of the stomach of the subjects. The fasting pH of 2·31 (SD 1·19) increased to a pH maxima of pH 6·54 (SD 0·29) after ingestion, with a subsequent decrease to pH 2·22 (SD 1·91) after 21 min (n 8). Fluorescence spectroscopy and Fourier transform IR spectroscopy revealed partial protein unfolding, coinciding with the decrease in pH below the isoelectric point of α-LA. The activity of pepsin in the fasting state was found to be 39 (SD 12) units/ml of gastric juice. Rapid digestion of the protein occurred: after 15 min, no native protein was detected using SDS-PAGE; HPLC revealed the presence of small amounts of native protein after 24 min of gastric digestion. Mirocam® capsule endoscopy imaging and video clips (see the online supplementary material) revealed that gastric peristalsis resulted in a heterogeneous mixture during gastric digestion. Unfolding of α-LA was observed during gastric transit; however, there was no evidence of a cytotoxic complex being formed between α-LA and OA.

Arabidopsis thaliana and Pisum sativum models demonstrate that root colonization is an intrinsic trait of Burkholderia cepacia complex bacteria.

Burkholderia cepacia complex (Bcc) bacteria possess biotechnologically useful properties that contrast with their opportunistic pathogenicity. The rhizosphere fitness of Bcc bacteria is central to their biocontrol and bioremediation activities. However, it is not known whether this differs between species or between environmental and clinical strains. We investigated the ability of 26 Bcc strains representing nine different species to colonize the roots of Arabidopsis thaliana and Pisum sativum (pea). Viable counts, scanning electron microscopy and bioluminescence imaging were used to assess root colonization, with Bcc bacteria achieving mean (±sem) levels of 2.49±0.23×10(6) and 5.16±1.87×10(6) c.f.u. per centimetre of root on the A. thaliana and P. sativum models, respectively. The A. thaliana rhizocompetence model was able to reveal loss of colonization phenotypes in Burkholderia vietnamiensis G4 transposon mutants that had only previously been observed in competition experiments on the P. sativum model. Different Bcc species colonized each plant model at different rates, and no statistical difference in root colonization was observed between isolates of clinical or environmental origin. Loss of the virulence-associated third chromosomal replicon (>1 Mb DNA) did not alter Bcc root colonization on A. thaliana. In summary, Bcc bacteria possess intrinsic root colonization abilities irrespective of their species or source. As Bcc rhizocompetence does not require their third chromosomal replicon, the possibility of using synthetic biology approaches to engineer virulence-attenuated biotechnological strains is tractable.

Revisiting quality of life for elders in long-term care: an integrative review.

PURPOSE: To review the literature on quality of life (QOL) among elders in long-term care settings, specifically focusing on measurement of QOL, influencing factors, and interventions to improve QOL. CONCLUSION: Multiple instruments were used to measure QOL with little overlap and limited ability to compare across studies. Categories of influencing factors included physical function, environment, social support, and mood/spiritual. Interventions targeted changes in environment, physical activity, and meaningful interaction. PRACTICE IMPLICATION: Knowledge of the factors influencing QOL and findings from research on interventions will assist nurses in individualizing care approaches to improve QOL among elders in long-term care settings.

Lipids as tumoricidal components of human α-lactalbumin made lethal to tumor cells (HAMLET): unique and shared effects on signaling and death.

Long-chain fatty acids are internalized by receptor-mediated mechanisms or receptor-independent diffusion across cytoplasmic membranes and are utilized as nutrients, building blocks, and signaling intermediates. Here we describe how the association of long-chain fatty acids to a partially unfolded, extracellular protein can alter the presentation to target cells and cellular effects. HAMLET (human α-lactalbumin made lethal to tumor cells) is a tumoricidal complex of partially unfolded α-lactalbumin and oleic acid (OA). As OA lacks independent tumoricidal activity at concentrations equimolar to HAMLET, the contribution of the lipid has been debated. We show by natural abundance (13)C NMR that the lipid in HAMLET is deprotonated and by chromatography that oleate rather than oleic acid is the relevant HAMLET constituent. Compared with HAMLET, oleate (175 µm) showed weak effects on ion fluxes and gene expression. Unlike HAMLET, which causes metabolic paralysis, fatty acid metabolites were less strongly altered. The functional overlap increased with higher oleate concentrations (500 µm). Cellular responses to OA were weak or absent, suggesting that deprotonation favors cellular interactions of fatty acids. Fatty acids may thus exert some of their essential effects on host cells when in the deprotonated state and when presented in the context of a partially unfolded protein.

Contrasting relationships between biogeochemistry and prokaryotic diversity depth profiles along an estuarine sediment gradient.

Detailed depth profiles of sediment geochemistry, prokaryotic diversity and activity (sulphate reduction and methanogenesis) were obtained along an estuarine gradient from brackish to marine, at three sites on the Colne estuary (UK). Distinct changes in prokaryotic populations [Archaea, Bacteria, sulphate-reducing bacteria (SRB) and methanogenic archaea (MA)] occurred with depth at the two marine sites, despite limited changes in sulphate and methane profiles. In contrast, the brackish site exhibited distinct geochemical zones (sulphidic and methanic) yet prokaryotic depth profiles were broadly homogenous. Sulphate reduction rates decreased with depth at the marine sites, despite nonlimiting sulphate concentrations, and hydrogenotrophic methanogenic rates peaked in the subsurface. Sulphate was depleted with depth at the brackish site, and acetotrophic methanogenesis was stimulated. Surprisingly, sulphate reduction was also stimulated in the brackish subsurface; potentially reflecting previous subsurface seawater incursions, anaerobic sulphide oxidation and/or anaerobic oxidation of methane coupled to sulphate reduction. Desulfobulbaceae, Desulfobacteraceae, Methanococcoides and members of the Methanomicrobiales were the dominant SRB and MA. Methylotrophic Methanococcoides often co-existed with SRB, likely utilising noncompetitive C1-substrates. Clear differences were found in SRB and MA phylotype distribution along the estuary, with only SRB2-a (Desulfobulbus) being ubiquitous. Results indicate a highly dynamic estuarine environment with a more complex relationship between prokaryotic diversity and sediment geochemistry, than previously suggested.

Alternatively folded proteins with unexpected beneficial functions.

HAMLET (human α-lactalbumin made lethal to tumour cells) and its related partially unfolded protein-fatty acid complexes are novel biomolecular nanoparticles that possess relatively selective cytotoxic activities towards tumour cells. One of the key characteristics is the requirement for the protein to be partially unfolded, hence endowing native proteins with additional functions in the alternatively folded states. Beginning with the history of its discovery and development, the cellular targets that appear to be strongly correlated with tumour cell death are introduced in the present article.

Modified linker-PCR primers facilitate complete sequencing of DGGE DNA fragments.

Modified linker-PCR primers were developed to enable complete sequencing of a DGGE band in one reaction. Commonly used bacterial and archaeal 16S rRNA gene PCR-DGGE primers were modified to contain linkers and sequencing primers. This protocol does not involve additional stages, and improves retrieval of sequence from DGGE bands by approximately 23%.

Identifying the genetic basis of ecologically and biotechnologically useful functions of the bacterium Burkholderia vietnamiensis.

Signature-tagged mutagenesis (STM) was used to identify genetic determinants of fitness associated with two key ecological processes mediated by bacteria. Burkholderia vietnamiensis strain G4 was used as a model bacterium to investigate: phenol degradation as a model of bioremediation, and pea rhizosphere colonization as a prerequisite to biological control and phytoremediation. A total of 1900 mutants were screened and 196 putative fitness mutants identified; the genetic basis of 137 of these mutations was determined by correlation to the G4 genome. The phenol-STM screen was more successful at identifying phenol degradation mutations (83 mutants; 4.4% hit rate) than a conventional agar-based phenol screen (49 mutants, 5319 screened, 0.92% hit rate). The combination of both screens completely defined the components of the TOM pathway in strain G4 and also identified novel accessory genes not previously implicated in phenol utilization. The rhizosphere-STM screen identified 113 mutants (5.9% hit rate); 107 had reduced tag signals indicative of poor rhizosphere colonization (Rhiz-), while six mutants produced high hybridization signals suggesting increased rhizosphere competence (Rhiz+). Competition assays confirmed that 69% of Rhiz- mutants tested (24/35) were severely compromised in their rhizosphere fitness. Seventy Rhiz- mutations mapped to genes with the following putative functions: amino acid biosynthesis (25; 36%), general metabolism (18; 26%), hypothetical (9; 13%), regulatory genes (4; 5.7%), transport and stress (2 each; 2.8% respectively). One of the most interesting discoveries mediated by the rhizosphere-STM screen was the identification of three Rhiz+ mutants inactivated within a single virulence-associated autotransporter adhesin gene; this mutation consistently produced a hyper-colonization phenotype suggesting a highly novel role for this surface adhesin during plant interactions. Our study has shown that STM can be successfully applied to ecologically important microbial interactions, defining the underlying genetic systems important for biotechnological fitness of environmental bacteria such those from the Burkholderia cepacia complex.