This thesis presents results from three studies conducted in a veterinary teaching hospital (VTH). Study 1 retrospectively examined a collection of enterococci from clinical infections. Five recurring strains of Enterococcus faecium, and one strain of Enterococcus faecalis were identified using pulsed-field gel electrophoresis (PFGE) as causing clinical infections. Study 2 examined the gastrointestinal tract enterococci as a source of enteroccocal infections in dogs. Enterococcal catheter-associated bacteriuria (CA-bacteriuria) rate was 8%. In 3 of 4 sets of bacteriuria and rectal isolates, CA-bacteriuria isolates were indistinguishable from rectal isolates suggesting that the patient’s fecal enterococci represented the infection source. In all 3 sets of wound and rectal isolates, fecal carriage of the infection isolate was observed. Study 3 examined the prevalence of bacterial species and the overall CA-bacteriuria rate. CA-bacteriuria rate was 24%, with Enterococcus spp., E. coli, Staphylococcus spp., Streptococcus spp. and Enterobacter spp., as the most prevalent bacteria in listed order. / PetTrust

Toxic cyanobacterial blooms constitute a threat to the safety and ecological quality of aquatic environments worldwide. Cyclic hepatotoxin, especially microcystin, is the most widely occurring of the cyanotoxins. The aim of this study was to identify the cyanobacterial genotypes present including how many toxic genotypes were present in two North American lakes and one African Lake. All three lakes are prone to cyanobacterial blooms and were sampled in 2005 and 2006: Lake Ontario (Bay of Quinte, Canada), Lake Erie (Maumee Bay, Canada) and Lake Victoria (Nyanza Gulf, Kenya). The cyanobacterial genotypic community was assessed using DNA based analyses of the hypervariable V3 region of the 16S rRNA gene. In addition, the aminotransferase (AMT) domain in modules mcyE and ndaF of the microcystin and nodularin gene cluster respectively was used to detect the presence of hepatotoxic genotypes. Denaturing gradient gel electrophoresis (DGGE) results from this study suggested that hepatotoxin producers were present in all study sites sampled and were most likely members of the genus Microcystis. This study was the first to report the potential for microcystin production in the in-shore and off-shore open lake of Nyanza Gulf in Kenya. A seasonal study of the Bay of Quinte and Maumee Bay showed differences in the cyanobacterial genotypic community from early to late summer. In addition, the cyanobacterial genotypic community from the Bay of Quinte differed from 2005 to 2006 and quantification of the North American samples revealed an increase in cyanobacterial cells from early to late summer. The Bay of Quinte saw relatively no change in hepatotoxic cells from early to late summer but in Maumee Bay hepatotoxic cells increased from undetectable in early summer to dominating the cyanobacterial community by late summer. This study demonstrated the use of DGGE and qPCR of the 16S rRNA-V3 and AMT gene region in monitoring the cyanobacterial community of waterbodies susceptible to toxic cyanobacterial blooms.

There is currently growing concern about the presence of heterotrophic plate count (HPC) bacteria in drinking water. These HPC may have potential pathogenic features, enabling them to cause disease. It is especially alarming amongst individuals with a weakened immune system. South Africa, the country with the highest incidents of HIV positive individuals in the world, mainly uses these counts to assess the quality of drinking water in terms of the number of micro-organisms present in the water. These micro-organisms may be present in the bulk water or as biofilms adhered to the surfaces of a drinking water distribution system. The current study investigated the pathogenic potential of HPC bacteria occurring as biofilms within a drinking water distribution system and determined the possible presence of these micro-organims within the bulk water. Biofilm samples were taken from five sites within a drinking water distribution system. Fifty six bacterial colonies were selected based on morphotypes and isolated for the screening of potential pathogenic features. Haemolysin production was tested for using sheep-blood agar plates. Of the 56, 31 isolates were ?-haemolytic. Among the 31 ?-haemolytic positive isolates 87.1% were positive for lecithinase, 41.9% for proteinase, 19.4% for chondroitinase, 9.7% for DNase and 6.5% for hyaluronidase. All of the ?-haemolytic isolates were resistant to oxytetracycline 30 ?g, trimethoprim 2.5 ?g and penicillin G10 units, 96.8% were resistant to vancomycin 30 ?g and ampicillin 10 ?g, 93.5% to kanamycin 30 ?g, 74.2% to chloramphenicol 30 ?g, 54.8% to ciprofloxacin 5 ?g, 22.6% to streptomycin 300 ?g and 16.1% to erythromycin 15 ?g. Nineteen isolates producing two or more enzymes were subjected to Gram staining. The nineteen isolates were all Gram-positive. These isolates were then identified using the BD BBL CRYSTALTM Gram-positive (GP) identification (ID) system. Isolates were identified as Bacillus cereus, Bacillus licheniformis, Bacillus subtilis, Bacillus megaterium, Bacillus pumilus and Kocuria rosea. 16S rRNA gene sequencing was performed to confirm these results and to obtain identifications for the bacteria not identified with the BD BBL CRYSTALTM GP ID system. Additionally identified bacteria included Bacillus thuringiensis, Arthrobacter oxydans and Exiguobacterium acetylicum. Morphological properties of the different species were studied with transmission electron microscopy (TEM) to confirm sequencing results. All the isolates displayed rod shaped cells with the exception of Arthrobacter oxydans being spherical in the stationary phase of their life cycle. Bulk water samples were taken at two sites in close proximity with the biofilm sampling sites. The DNA was extracted directly from the water samples and the 16S rRNA gene region was amplified. Denaturing gradient gel electrophoresis (DGGE) was performed to confirm the presence of the isolates from the biofilm samples in the bulk water samples. The presence of Bacillus pumilus and Arthrobacter oxydans could be confirmed with DGGE. This study demonstrated the presence of potentially pathogenic HPC bacteria within biofilms in a drinking water distribution system. It also confirmed the probable presence of two of these biofilm based bacteria in the bulk water. / Thesis (M.Sc. (Microbiology))--North-West University, Potchefstroom Campus, 2010.

Despite emerging water shortages, most water is only used once, and often with low efficiency. However, with appropriate treatment, water can be re–used to reduce the demand on freshwater sources. The Department of Water Affairs, South Africa, promotes industries to reduce discharges into water resources in order to sustain an overall good water quality of all water systems. All of this ultimately leads to industries striving towards zero effluent discharge. Primary Column Bottoms (PCBs) is a wastewater stream derived from the Fischer–Tropsch Gas to Liquid process and consists mainly of organic acids, but no nitrogen or phosphorous, which by implication excludes possible biodegradation. In the operation of cooling towers in industrial processes, cooling water quality has a direct impact on the cooling performance of the system, where nutrient levels may affect fouling, scaling and corrosion observed in the cooling towers. Fouling, scaling and corrosion affect the operating efficiency of cooling water systems and may necessitate the addition of chemical agents to control these phenomena. This has a financial and labour time impact on the operation of these systems. In this study a mini cooling tower test rig was operated with a synthetic PCB effluent as cooling water and various cycles of concentration, pH and linear flow velocities (LFVs). A constant delta temperature of 10 °C was maintained. Cycles of concentration (COC) evaluated included 2, 4 and 6 cycles of concentration and linear flow velocities evaluated was 0.6 m/s, 0.9 m/s and 1.2 m/s. Fouling, scaling and corrosion rates were determined using corrosion coupons and heat exchanger tubes for mild steel and stainless steel. Besides the evaluation of the various operational parameters for fouling, scaling and corrosion, the possibility for chemical oxygen demand (COD) removal by operating the cooling tower as a bioreactor was also evaluated. To this end nutrient correction was applied to the reactor to allow for a CNP ratio of 100:10:1. With regard to fouling, scaling and corrosion, mild steel was more affected by fouling, scaling and corrosion compared to stainless steel where almost no fouling, scaling and corrosion was observed. Overall increased linear flow velocities resulted in higher fouling and scaling rates, whereas lower linear flow velocities resulted in decreased corrosion rates. In terms of cycles of concentration, increased COC resulted in higher fouling, scaling and corrosion rates. Despite the high nutrient removal levels, the accompanying fouling, scaling and corrosion was still below the particular industry’s guidelines. Besides physical–chemical evaluation of the towers under the various operational conditions, culture–dependent and culture–independent methods were also employed. Concerning culture–dependent approaches the study demonstrated that aerobic and anaerobic organisms are present in both the planktonic and sessile phase of the cooling tower reactors. Heterotrophic aerobes were found to be the most abundant under all the operating conditions. Sulphate reducing bacteria were more abundant in the sessile phase of the cooling towers, and the presence of high sulphate levels in the experiments could be indicative of the sulphate reducing bacteria actively participating in the microbial community. Lower than expected corrosion levels, however, suggest that a combination of the organisms in the biofilm rather than sulphate reducing bacteria alone, contributed to the corrosion rates observed. Culture–independent methods, specifically phospholipid fatty acid analysis supported the results from the culture–dependent methods. Furthermore results demonstrated that linear flow velocity had a greater effect on the community structure than cycles of concentration. Finally molecular methods, specifically denaturing gradient gel electrophoresis, found that increasing cycles of concentration resulted in increased microbial community diversity, while increasing linear flow velocity resulted in decreased microbial community diversity. Regarding COD removal, nutrient correction of the synthetic PCB effluent achieved 89.35 % COD removal at 2 COC and 1.2 m/s LFV, while 80.85 % COD removal was achieved at 4 COC at 1.2 m/s LFV. From these results it was recommended that the operation of the cooling tower should be at 4 COC and 1.2 m/s, which despite slightly lower % COD removal, were characterised by fouling, scaling and corrosion rates well within guidelines. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2012.

There is currently growing concern about the presence of heterotrophic plate count (HPC) bacteria in drinking water. These HPC may have potential pathogenic features, enabling them to cause disease. It is especially alarming amongst individuals with a weakened immune system. South Africa, the country with the highest incidents of HIV positive individuals in the world, mainly uses these counts to assess the quality of drinking water in terms of the number of micro-organisms present in the water. These micro-organisms may be present in the bulk water or as biofilms adhered to the surfaces of a drinking water distribution system. The current study investigated the pathogenic potential of HPC bacteria occurring as biofilms within a drinking water distribution system and determined the possible presence of these micro-organims within the bulk water. Biofilm samples were taken from five sites within a drinking water distribution system. Fifty six bacterial colonies were selected based on morphotypes and isolated for the screening of potential pathogenic features. Haemolysin production was tested for using sheep-blood agar plates. Of the 56, 31 isolates were ?-haemolytic. Among the 31 ?-haemolytic positive isolates 87.1% were positive for lecithinase, 41.9% for proteinase, 19.4% for chondroitinase, 9.7% for DNase and 6.5% for hyaluronidase. All of the ?-haemolytic isolates were resistant to oxytetracycline 30 ?g, trimethoprim 2.5 ?g and penicillin G10 units, 96.8% were resistant to vancomycin 30 ?g and ampicillin 10 ?g, 93.5% to kanamycin 30 ?g, 74.2% to chloramphenicol 30 ?g, 54.8% to ciprofloxacin 5 ?g, 22.6% to streptomycin 300 ?g and 16.1% to erythromycin 15 ?g. Nineteen isolates producing two or more enzymes were subjected to Gram staining. The nineteen isolates were all Gram-positive. These isolates were then identified using the BD BBL CRYSTALTM Gram-positive (GP) identification (ID) system. Isolates were identified as Bacillus cereus, Bacillus licheniformis, Bacillus subtilis, Bacillus megaterium, Bacillus pumilus and Kocuria rosea. 16S rRNA gene sequencing was performed to confirm these results and to obtain identifications for the bacteria not identified with the BD BBL CRYSTALTM GP ID system. Additionally identified bacteria included Bacillus thuringiensis, Arthrobacter oxydans and Exiguobacterium acetylicum. Morphological properties of the different species were studied with transmission electron microscopy (TEM) to confirm sequencing results. All the isolates displayed rod shaped cells with the exception of Arthrobacter oxydans being spherical in the stationary phase of their life cycle. Bulk water samples were taken at two sites in close proximity with the biofilm sampling sites. The DNA was extracted directly from the water samples and the 16S rRNA gene region was amplified. Denaturing gradient gel electrophoresis (DGGE) was performed to confirm the presence of the isolates from the biofilm samples in the bulk water samples. The presence of Bacillus pumilus and Arthrobacter oxydans could be confirmed with DGGE. This study demonstrated the presence of potentially pathogenic HPC bacteria within biofilms in a drinking water distribution system. It also confirmed the probable presence of two of these biofilm based bacteria in the bulk water. / Thesis (M.Sc. (Microbiology))--North-West University, Potchefstroom Campus, 2010.

Despite emerging water shortages, most water is only used once, and often with low efficiency. However, with appropriate treatment, water can be re–used to reduce the demand on freshwater sources. The Department of Water Affairs, South Africa, promotes industries to reduce discharges into water resources in order to sustain an overall good water quality of all water systems. All of this ultimately leads to industries striving towards zero effluent discharge. Primary Column Bottoms (PCBs) is a wastewater stream derived from the Fischer–Tropsch Gas to Liquid process and consists mainly of organic acids, but no nitrogen or phosphorous, which by implication excludes possible biodegradation. In the operation of cooling towers in industrial processes, cooling water quality has a direct impact on the cooling performance of the system, where nutrient levels may affect fouling, scaling and corrosion observed in the cooling towers. Fouling, scaling and corrosion affect the operating efficiency of cooling water systems and may necessitate the addition of chemical agents to control these phenomena. This has a financial and labour time impact on the operation of these systems. In this study a mini cooling tower test rig was operated with a synthetic PCB effluent as cooling water and various cycles of concentration, pH and linear flow velocities (LFVs). A constant delta temperature of 10 °C was maintained. Cycles of concentration (COC) evaluated included 2, 4 and 6 cycles of concentration and linear flow velocities evaluated was 0.6 m/s, 0.9 m/s and 1.2 m/s. Fouling, scaling and corrosion rates were determined using corrosion coupons and heat exchanger tubes for mild steel and stainless steel. Besides the evaluation of the various operational parameters for fouling, scaling and corrosion, the possibility for chemical oxygen demand (COD) removal by operating the cooling tower as a bioreactor was also evaluated. To this end nutrient correction was applied to the reactor to allow for a CNP ratio of 100:10:1. With regard to fouling, scaling and corrosion, mild steel was more affected by fouling, scaling and corrosion compared to stainless steel where almost no fouling, scaling and corrosion was observed. Overall increased linear flow velocities resulted in higher fouling and scaling rates, whereas lower linear flow velocities resulted in decreased corrosion rates. In terms of cycles of concentration, increased COC resulted in higher fouling, scaling and corrosion rates. Despite the high nutrient removal levels, the accompanying fouling, scaling and corrosion was still below the particular industry’s guidelines. Besides physical–chemical evaluation of the towers under the various operational conditions, culture–dependent and culture–independent methods were also employed. Concerning culture–dependent approaches the study demonstrated that aerobic and anaerobic organisms are present in both the planktonic and sessile phase of the cooling tower reactors. Heterotrophic aerobes were found to be the most abundant under all the operating conditions. Sulphate reducing bacteria were more abundant in the sessile phase of the cooling towers, and the presence of high sulphate levels in the experiments could be indicative of the sulphate reducing bacteria actively participating in the microbial community. Lower than expected corrosion levels, however, suggest that a combination of the organisms in the biofilm rather than sulphate reducing bacteria alone, contributed to the corrosion rates observed. Culture–independent methods, specifically phospholipid fatty acid analysis supported the results from the culture–dependent methods. Furthermore results demonstrated that linear flow velocity had a greater effect on the community structure than cycles of concentration. Finally molecular methods, specifically denaturing gradient gel electrophoresis, found that increasing cycles of concentration resulted in increased microbial community diversity, while increasing linear flow velocity resulted in decreased microbial community diversity. Regarding COD removal, nutrient correction of the synthetic PCB effluent achieved 89.35 % COD removal at 2 COC and 1.2 m/s LFV, while 80.85 % COD removal was achieved at 4 COC at 1.2 m/s LFV. From these results it was recommended that the operation of the cooling tower should be at 4 COC and 1.2 m/s, which despite slightly lower % COD removal, were characterised by fouling, scaling and corrosion rates well within guidelines. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2012.

A proteomics approach was used to identify proteins potentially implicated in the cellular response concurrent with elevated production levels of human follicle stimulating hormone in a recombinant Chinese hamster ovary cell line (Darren cells), using zinc and sodium butyrate in the production media to increase expression. To this end, 2-dimensional gel electrophoresis (2-DGE) was utilized. Firstly, several aspects of 2-DGE were developed for this investigation. Gel drying conditions were optimized, and a glycine-free blotting method is described which achieved greater efficiency in rapid transfer of proteins than those previously described. Next, hFSH expression was characterized in Darren cells. An ELISA developed for this investigation examined intracellular (expression) and extracellular (secretion) of hFSH during increased expression. These results show a disproportionate increase in intracellular hFSH (188%) expression above extracellular hFSH (41%).

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 82-88).

Thesis (Ph. D.)(Microbiology)--University of Pretoria, 2007. / Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (MSc Food Sc )--Stellenbsosch University, 2003. / ENGLISH ABSTRACT: Kepi is a fermented milk beverage that originated in Eastern Europe. Traditional Kepi is a lightly acidic, carbonated beverage, with a slight yeasty taste. The starter used to produce this beverage is an irregularly shaped, yellowish-white grain-like structure similar in appearance to a cauliflower floret. The characteristic flavour of Kepi is produced by a complex spectrum of microbial species that include species of yeasts, lactic acid bacteria, acetic acid bacteria and mycelial fungi. At the end of the fermentation process the grainy starter can be recovered and re-used, since the microbes can easily be recovered as a solid matrix. The microbes comprising Kepi grains have only been identified using classical identification techniques such as selective growth media, morphological, physiological and biochemical characteristics. In this study, polymerase chain reaction (PCR)-based denaturing gradient gel electrophoresis (DGGE) analysis was used to typify and identify the complex microbial consortium present in the Kepi grains. A part of the 168 ribosomal RNA (rRNA) gene from the microbial population in mass-cultured, traditionally cultured and Irish Kepi grains were amplified using 'Eubacterial' specific primers and a part of the 268 rRNA gene was amplified using yeast specific primers. The PCR fragments were resolved by DGGE, resulting in unique fingerprints for the Eubacteria and yeasts present in the different Kepi grain types. The traditionally cultured Kepi grains were found to incorporate the most Eubacteria and yeast species, while the mass-cultured Kepi grains contained the lowest number of Eubacteria and yeast species. The different Eubacteria and yeast species were identified by cloning the PCR products and sequencing the cloned inserts. The obtained DNA sequences were compared to sequences available on the NCBI website. 8ix lactobacilli were identified: Lb. crispatus (KC-4); three Lb. species (KC-36, KC-38 and KC-43); and two unculturable lactobacilli (KC-2 and KC-3). The yeasts were identified as Saccharomyces cerevisiae (KC-y18) and Candida lambica (KC-y1). Unidentified isolates from kefiran strings that could not be identified using traditional methods were also identified by cloning the PCR products and sequencing the cloned inserts. The four isolates were identified as Lb. kefiri (KGI-A), Lb. parakefiri (KGIB), Lb. gallina rum (KGI-D) and an unculturable Lactobacillus (KGI-5). The phylogenetic relationship between the identified lactobacilli and the lactobacilli commonly found in Kepi grains was determined. The identified lactobacilli were grouped together in a clade with a bootstrap support value of 84%. The clade also contained representatives of Lb. delbrueckii subsp. lactis, Lb. acidophilus, Lb. gallinarum, Lb. helveticus, Lb. crispatus, Lb. species and unculturable lactobacilli. The bands in the peR-based DGGE fingerprints of the Eubacteria and the yeasts were identified, and a DGGE marker was subsequently constructed for the rapid identification of the Eubacteria present in mass-cultured Kepi grains. The data obtained in this study clearly showed that Kepi grains that are cultured differently, as well as Kepi grains from different origins have unique peRbased DGGE banding patterns for both the Eubacteria and yeasts present in the grains. The complex microbial consortium comprising Kepi grains could be typified and identified using PeR-based DGGE, DNA cloning and sequencing. The identification of the members of the microbial consortium is of importance for the future commercialisation of the mass-cultured Kepi grains. / AFRIKAANSE OPSOMMING: Kepi is 'n gefermenteerde melkdrankie wat sy oorsprong het in Oos Europa. Tradisionele Kepi is 'n effens suur, gekarboneerde drankie wat effens na gis smaak. Die beginkultuur wat gebruik word om dié drankie te maak is 'n oneweredige, geel-wit korrelagtige struktuur wat baie lyk soos 'n blomkoolkoppie. Die karakteristieke smaak van Kepi word geproduseer deur 'n komplekse spektrum mikrobiese spesies wat giste, melksuur- en asynsuurbakterieë en ~. misillêre fungi insluit. Aan die einde van die fermentasieproses kan die korrelagtige beginkultuur herwin word en weer gebruik word, aangesien die mikrobes maklik herwin kan word as 'n soliede matriks. Die mikrobes waaruit Kepikorrels bestaan, is nog slegs met behulp van klassieke identifikasiemetodes soos selektiewe groeimedia, morfologiese, fisiologiese and biochemiese eienskappe geïdentifiseer. In hierdie studie is polimerase kettingreaksie (PKR)-gebaseerde denaturerende gradiënt jelelektroforese (DGGE) analise gebruik om die komplekse mikrobiologiese konsortium in die Kepikorrels te tipeer en te identifiseer. 'n Gedeelte van die 16S ribosomale RNS (rRNS) geen van die mikrobiologiese populasie in massagekweekte, tradisioneel gekweekte en Ierse Kepikorrels is geamplifiseer met 'Eubakferiële' spesifieke peilers en In gedeelte van die 26S rRNS geen is geamplifiseer met gis spesifieke peilers. Die PKR fragmente is onderskei deur DGGE, wat unieke vingerafdrukke vir die Eubakteriële- en gisspesies in die verskillende Kepikorrel tipes gelewer het. Die tradisioneel gekweekte Kepikorrels het die meeste Eubakteriële- en gisspesies geïnkorporeer, terwyl die Ierse Kepikorrels die minste Eubakteriële- en gisspesies geïnkorporeer het. Die verskillende Eubakteriële- en gisspesies is geïdentifiseer deur klonering van die PKR produkte en deur die gekloneerde insetsels se volgordes te bepaal. Die ONS volgordes is dan vergelyk met volgordes wat op die NCSI webwerf beskikbaar is. Ses lactobacilli is geïdentifiseer: Lb. ctispetus (KC-4); drie Lb. spesies (KC-36, KC-38 en KC-43); en twee onkultiveerbare lactobacilli (KC-2 en KC-3). Die giste is geïdentifiseer as Saccharomyces cerevisiae (KC-y18) en Candida lambica (KC-y1). Ongeïdentifiseerde isolate van kefiranstringe is ook geïdentifiseer deur klonering van die PKR produkte en deur die gekloneerde insetsels se volgorde te bepaal. Dié vier isolate is geïdentifiseer as Lb. kefiri (KGIA), Lb. parakefiri (KGI-B), Lb. gallina rum (KGI-D) en 'n onkultiveerbare Lactobacillus (KGI-5). Die filogenetiese verwantskap is bepaal tussen die geïdentifiseerde lactobacilli en lactobacilli wat geredelik in Kepikorrels gevind word. Die geïdentifiseerde lactobacilli was saam in 'n groep gegroepeer met 'n bootstrap waarde van 84%. Die groep het ook verteenwoordigers van Lb. delbrueckii subsp. lactis, Lb. acidophilus, Lb. gallina rum, Lb. helveticus, Lb. crispatus, Lb. species en 'n onkultiveerbare laktobacilli ingesluit. Die bande in die PKR-gebaseerde DGGE vingerafdrukke van die Eubakterieë en die giste is geïdentifiseer, en 'n DGGE merker is gemaak vir die vinnige identifikasie van die Eubakterieë wat in die massagekweekte Kepikorrels teenwoordig is. Die data wat in die studie verkry, is wys duidelik dat Kepikorrels wat op verskillende maniere gekweek is, en wat verskillende oorspronge het, unieke PKR-gebaseerde DGGE bandpatrone het vir beide die Eubakterieë en giste wat in die korrels teenwoordig is. Die komplekse mikrobiologiese konsortium waaruit Kepikorrels bestaan kon getipeer en geïdentifiseer word deur PKR-gebaseerde DGGE, klonering van DNS en volgordebepaling. Die identifikasie van lede van die mikrobiologiese konsortium is belangrik vir die toekomstige kommersialisasie van die massagekweekte Kepikorrels.