Abstract. Klebsiella became an increasingly important source of community-acquired and nosocomial infections. Extensive broad-spectrum utilization of antibiotics in hospitalized patients has contributed to both increased carriages of Klebsiella and the development of multidrug-resistant strains. Many of these strains are extremely virulent and show a strong tendency to spread. Bacteriophages, viruses that because bacterial lysis can serve as a useful tool for Klebsiella infection control. In this study, two lytic phages designated as ØKPAS1 and ØKPAS2 infecting multidrug-resistant K. pneumoniae were isolated from sewage samples collected in Assiut, Egypt. Using transmission electron microscopy, the morphology of isolated phages was characterized, and their host range was determined. The morphological analysis revealed that both phages belong to the Podoviridae family. ØKPAS1 has ahead of about 50 ± 5 nm in diameter and a short tail of 20 ± 2 nm in length, while ØKPAS2 has ahead of about 53 ± 5 nm in diameter with a short tail of 19 ± 2 nm in length. ØKPAS1 phage showed a broader host range within genus Klebsiella since it was able to lyse 8 out of 15 different Klebsiella cultures while ØKPAS2 was able to lyse only 5 out of 15. Both phages could not infect bacteria from other genera such as Escherichia coli and Salmonella typhi. The isolated phage ØKPAS1 was able to survive at a temperature up to 50 ᵒC and was infective in pH range between 4.0-9.0, while ØKPAS2 was able to survive at a temperature up to 60 ᵒC and was stable over the pH range of 4,0 to10,0. Both phages were stable in chloroform. One-step growth curves of ØKPAS1 and ØKPAS2 revealed that the latent period was 10 min for either phage, with burst sizes of about 120 and 245 pfu/ml for ØKPAS1 and ØKPAS2, respectively.

NULLAbstract Aims: The major aims of this study are to determine the capability of sulphur oxidizing bacterium (SOB-1) to desulphurize dibenzothiophene (DBT) and crude oil, detection of the reaction kinetics and identify the proposed pathway of DBT desulphurization. Methods and Results: The isolate was genetically identified based on 16S rRNA gene sequencing as Klebsiella oxytoca and deposited in the Genebank database under the accession number: MT355440. The HPLC analysis of the remaining DBT concentration revealed that, SOB-1 could desulphurize 90% of DBT (0
25 mmol l−1) within 96 h. The maximum production of sulphate ions from the desulphurization of DBT (0
36 mmol l−1) and crude oil (0
4 mmol l−1) could be quantitatively detected after 48 h of incubation at 30°C. The high values of correlation coefficient (R2) obtained at all studied concentrations; suggested that biodesulfurization kinetics of DBT follows the first-order reaction model. The kinetics studies showed that, DBT may have an inhibitory effect on SOB-1 when the initial concentration exceeded 0
75 mmol l−1. The GC-MS analysis exhibited four main metabolites rather than DBT. The most important ones are 2-hydroxybiphenyl (2-HBP) and methoxybiphenyl n(2-MBP). Conclusions: Klebsiella oxytoca SOB-1 catalyzes the desulphurization of DBT through 4S pathway and forms four main metabolic products. The release of sulphate ion and formation of 2-HBP indicating the elimination of sulphur group without altering the carbon skeleton of DBT. The bacterial strain could also catalyzes desulphurization of crude oil. The desulphurization kinetics follows the first-order reaction model. Significance and Impact of the Study: Klebsiella oxytoca SOB-1 could be used as a promising industrial and environmental biodesulfurizing agent as it is not affecting carbon skeleton of thiophenic compounds and forming less toxic metabolic product (2-MBP).

NULLAbstract Aims: The major aims of this study are to determine the capability of sulphur oxidizing bacterium (SOB-1) to desulphurize dibenzothiophene (DBT) and crude oil, detection of the reaction kinetics and identify the proposed pathway of DBT desulphurization. Methods and Results: The isolate was genetically identified based on 16S rRNA gene sequencing as Klebsiella oxytoca and deposited in the Genebank database under the accession number: MT355440. The HPLC analysis of the remaining DBT concentration revealed that, SOB-1 could desulphurize 90% of DBT (0
25 mmol l−1) within 96 h. The maximum production of sulphate ions from the desulphurization of DBT (0
36 mmol l−1) and crude oil (0
4 mmol l−1) could be quantitatively detected after 48 h of incubation at 30°C. The high values of correlation coefficient (R2) obtained at all studied concentrations; suggested that biodesulfurization kinetics of DBT follows the first-order reaction model. The kinetics studies showed that, DBT may have an inhibitory effect on SOB-1 when the initial concentration exceeded 0
75 mmol l−1. The GC-MS analysis exhibited four main metabolites rather than DBT. The most important ones are 2-hydroxybiphenyl (2-HBP) and methoxybiphenyl n(2-MBP). Conclusions: Klebsiella oxytoca SOB-1 catalyzes the desulphurization of DBT through 4S pathway and forms four main metabolic products. The release of sulphate ion and formation of 2-HBP indicating the elimination of sulphur group without altering the carbon skeleton of DBT. The bacterial strain could also catalyzes desulphurization of crude oil. The desulphurization kinetics follows the first-order reaction model. Significance and Impact of the Study: Klebsiella oxytoca SOB-1 could be used as a promising industrial and environmental biodesulfurizing agent as it is not affecting carbon skeleton of thiophenic compounds and forming less toxic metabolic product (2-MBP).

NULLAbstract Aims: The major aims of this study are to determine the capability of sulphur oxidizing bacterium (SOB-1) to desulphurize dibenzothiophene (DBT) and crude oil, detection of the reaction kinetics and identify the proposed pathway of DBT desulphurization. Methods and Results: The isolate was genetically identified based on 16S rRNA gene sequencing as Klebsiella oxytoca and deposited in the Genebank database under the accession number: MT355440. The HPLC analysis of the remaining DBT concentration revealed that, SOB-1 could desulphurize 90% of DBT (0
25 mmol l−1) within 96 h. The maximum production of sulphate ions from the desulphurization of DBT (0
36 mmol l−1) and crude oil (0
4 mmol l−1) could be quantitatively detected after 48 h of incubation at 30°C. The high values of correlation coefficient (R2) obtained at all studied concentrations; suggested that biodesulfurization kinetics of DBT follows the first-order reaction model. The kinetics studies showed that, DBT may have an inhibitory effect on SOB-1 when the initial concentration exceeded 0
75 mmol l−1. The GC-MS analysis exhibited four main metabolites rather than DBT. The most important ones are 2-hydroxybiphenyl (2-HBP) and methoxybiphenyl n(2-MBP). Conclusions: Klebsiella oxytoca SOB-1 catalyzes the desulphurization of DBT through 4S pathway and forms four main metabolic products. The release of sulphate ion and formation of 2-HBP indicating the elimination of sulphur group without altering the carbon skeleton of DBT. The bacterial strain could also catalyzes desulphurization of crude oil. The desulphurization kinetics follows the first-order reaction model. Significance and Impact of the Study: Klebsiella oxytoca SOB-1 could be used as a promising industrial and environmental biodesulfurizing agent as it is not affecting carbon skeleton of thiophenic compounds and forming less toxic metabolic product (2-MBP).

NULL

NULL

NULL

NULL

Data from the Gravity Recovery and Climate Experiment (GRACE) and outputs of the CLM4.5 model were used to estimate recharge and depletion rates for large aquifers, investigate the connectivity of an aquifer’s subbasins, and identify barriers and preferred pathways for groundwater flow within an aquifer system. The Nubian Sandstone Aquifer System and its subbasins (Dakhla, Northern Sudan Platform, and Kufra) in northeast Africa were used for demonstration purposes, and findings were tested and verified against geological, geophysical, remote sensing, geochronologic, and geochemical data. There are four major findings. (1) The average annual precipitation data over recharge areas in the southern Kufra section and the Northern Sudan Platform subbasin were estimated at 54.8 km3, and 32.8 km3, respectively, and knowing the annual extraction rates over these two areas (~0.40 ± 0.20 km3), recharge rates were estimated at 0.78 ± 0.49 km3/yr and 1.44 ± 0.42 km3/yr, respectively. (2) GRACEderived groundwater depletion rates over the Dakhla subbasin and the Northern Kufra section were estimated at 4.44 ± 0.42 km3/yr and 0.48 ± 0.32 km3/yr, respectively. (3) The observed depletion in the southern parts of the Dakhla subbasin is apparently caused by the presence of the east-west–trending Uweinat-Aswan basement uplift, which impedes the south-to-north groundwater flow and hence reduces replenishment from recharge areas in the south. (4) A major northeast- southwest–trending shear zone (Pelusium shear system) is apparently providing a preferred groundwater flow pathway from the Kufra to the Dakhla subbasin. Our integrated approach provides a replicable and cost-effective model for better understanding of the hydrogeologic setting of large aquifers worldwide and for optimum management of these groundwater resources.

Data from the Gravity Recovery and Climate Experiment (GRACE) and outputs of the CLM4.5 model were used to estimate recharge and depletion rates for large aquifers, investigate the connectivity of an aquifer’s subbasins, and identify barriers and preferred pathways for groundwater flow within an aquifer system. The Nubian Sandstone Aquifer System and its subbasins (Dakhla, Northern Sudan Platform, and Kufra) in northeast Africa were used for demonstration purposes, and findings were tested and verified against geological, geophysical, remote sensing, geochronologic, and geochemical data. There are four major findings. (1) The average annual precipitation data over recharge areas in the southern Kufra section and the Northern Sudan Platform subbasin were estimated at 54.8 km3, and 32.8 km3, respectively, and knowing the annual extraction rates over these two areas (~0.40 ± 0.20 km3), recharge rates were estimated at 0.78 ± 0.49 km3/yr and 1.44 ± 0.42 km3/yr, respectively. (2) GRACEderived groundwater depletion rates over the Dakhla subbasin and the Northern Kufra section were estimated at 4.44 ± 0.42 km3/yr and 0.48 ± 0.32 km3/yr, respectively. (3) The observed depletion in the southern parts of the Dakhla subbasin is apparently caused by the presence of the east-west–trending Uweinat-Aswan basement uplift, which impedes the south-to-north groundwater flow and hence reduces replenishment from recharge areas in the south. (4) A major northeast- southwest–trending shear zone (Pelusium shear system) is apparently providing a preferred groundwater flow pathway from the Kufra to the Dakhla subbasin. Our integrated approach provides a replicable and cost-effective model for better understanding of the hydrogeologic setting of large aquifers worldwide and for optimum management of these groundwater resources.