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by
Jacob H. Jacob |
Total Records (
4 ) for
Jacob H. Jacob |
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Jacob H. Jacob
and
Sohail Alsohaili
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In this study, we aimed at isolating fungal strains from the indoor environment that tolerate or/and degrade phenol as sole carbon and energy source. Subsequently, we isolated two fungi (IF2 and IF3, identified as Alternaria sp. and Penicillium sp., respectively) showed the ability to degrade phenol as sole carbon and energy source in mineral medium. Growth with phenol was monitored by increase in biomass measured as dry weight and depletion of phenol measured by gas chromatography. Both strains were also grown with lactose as reference. The IF2 showed higher phenol degradation capacity (18.6 μg L-1) than IF3 (5.4 μg L-1). |
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Jacob H. Jacob
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Halophilic heterotrophic bacteria are distinguished group of microorganisms thriving at saline environments like natural salt lakes. The Dead sea of Jordan is one of the remarkable natural hypersaline inland salt lakes in the world. In this study, we aimed to classify bacterial species living in this unique environment. Water samples, collected during March, July, and October, 2011, were first analyzed in respect to salinity, pH, biological oxygen demand (BOD), and viable microbial number. The salinity of our samples were relatively very high (up to 38%), the pH was slightly low (5.6-6.3) and the BOD was very low (1-2 mg O2 L-1). These conditions were translated into very low viable plate count (2-60x102 CFU mL-1). To classify the indigenous halophilic heterotrophic bacterial species, water samples were first enriched in high salinity medium leading to isolation of 44 heterotrophic halophilic bacterial species, 11 of them were considered different based on Gram-stain as well as colonial and cell morphology. These strains were further analyzed by sequencing their 16S RNA gene. All isolates were found to belong to 7 genera of the domain of Bacteria: Arthrobacter, Kocuria, Vibrio, Salinivibrio, Chromohalobacter, Bacillus and Erythrobacter. Most strains have a high GC content (up to 58%) and some strains are not common in hypersaline environments. |
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Emad I. Hussein
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Jacob H. Jacob
,
Abdel-Salam F. Jahmani
and
Nigem Din Yousef
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Zarqa River (ZR) is an important river basin in Jordan. However,
it is continuously exposed to different types of pollutants including heavy
metals. This study was carried out to determine the concentration of the following
heavy metals in this vital environment: Pb, Cd, Cu and Zn and to enumerate,
isolate and characterize the indigenous bacteria inhabiting this environment
to test their heavy metal tolerance and bioremoval ability. Samples in this
study include four different types: water, soil, sediment and three local plants
(Nerium oleander, Phragmites australis and Nicotenia glauca)
from 13 sampling sites assigned as A1-A13 starting from Kherbat Al-Samra treatment
plant and ending at King Talal dam. High concentration of Pb was detected in
water samples from site A1 (3200 mg L-1) as well as Cd from site
A13 (2500 mg L-1). In soil, Zn was found at high concentrations in
all sampling sites while Cd was found at high concentration only in site A12.
High concentrations of Zn and Cu were detected in sediment samples from sites
A1 and A8, respectively. In case of plant samples, Zn was detected at high concentration
in Nicotenia glauca. A relatively high viable bacterial counts in site
A12 soil and sediment samples were detected (2x1015 and 1.8x1014
CFU mL-1, respectively) and in site A13 water samples (6x1017
CFU mL-1). Identified bacteria belong to Staphylococcus,
Escherichia, Lactobacillus, Bacillus, Pseudomonas,
Micrococcus, Klebsiella, Enterobacter, Alcaligenes,
Mycobacterium, Citrobacter, Corynebacterium, Acetobacter,
Serratia and Salmonella. Among them, Corynebacterium sp.,
was the most effective in heavy metal bioremoval. |
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Emad I. Hussein
,
Ghassan J. M. Kanan
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Khalid M. Al- Batayneh
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Khalaf Alhussaen
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Wesam Al Khateeb
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Janti Qar
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Jacob H. Jacob
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Riyadh Muhaidat
and
Mohamed I. Hegazy
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The post-harvest moulds Penicillium digitatum and Penicillium italicum
are important plant pathogens and spoilage-causing molds especially against
citrus fruits. If not treated, post-harvest moulds can cause enormous economic
losses during storage and marketing. Therefore, more investigations are needed
to examine new antifungal agents against such fungi. In this work, we aimed
to evaluate the antifungal activity of some plant extracts (namely, Harmal seeds
(Peganum harmala L.), cinnamon bark (Cinnamomum cassia L.) and
sticky fleabane leaves (Inula viscosa L.), food preservatives (namely,
sodium benzoate, sodium molybdate, ammonium heptamolybdate tetrahydrate, potassium
carbonate and sodium bicarbonate) and their mixtures, i.e., plant extracts and
food preservatives against P. digitatum and P. italicum. Both
disc agar diffusion method and broth dilution methods was used to evaluate the
antifungal activity of the plant extracts and food preservatives. Results revealed
that methanolic fractions of cinnamons’
bark and sticky fleabane leaves showed the highest efficacy. MIC values of 150
and 37.5 μg mL-1 were obtained with cinnamons’ fraction against
P. italicum and P. digitatum, respectively. Sodium benzoate was
the most effective against tested fungal species. The obtained MIC values against
P. digitatum and P. italicum were 37.5 and 75 μg mL-1,
respectively. Mixtures of tested chemicals showed synergistic effects against
both fungal species. Mixtures of sodium benzoate and fractions of either cinnamon
or sticky fleabane reflected synergistic effects against P. italicum
and antagonistic effects against P. digitatum. Inhibition zones against
P. italicum ranged between 38-57 mm. |
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