Abstract: EcoDam is an adenine-N6 DNA methyltransferase
that methylates the GATC sites in the Escherichia coli genome.
DNA-adenine methylation is not present in higher eukaryotes
including humans. These observations raise the possibility that dam
inhibitors may be used as anti-microbial agents. Polyphosphate
(Poly(P)) is an important metabolite and signaling molecule in
prokaryotes and eukaryotes. Here, by using gel retardation
experiments to investigate the competition of DNA binding by
EcoDam in the presence of polyphosphate, we found that Poly (P)
strongly interferes with DNA binding by EcoDam, while same
concentration of monophosphate does not. In addition, we
demonstrated that Poly (P) binding inhibits the activity of EcoDam
and our results suggest that Poly (P) led to strong inhibition of the
EcoDam catalytic activity, while monophosphate had only moderate
effect.
Abstract: MinC plays an important role in bacterial cell division
system by inhibiting FtsZ assembly. However, the molecular
mechanism of the action is poorly understood. E. coli MinC Nterminus
domain was purified and crystallized using 1.4 M sodium
citrate pH 6.5 as a precipitant. X-ray diffraction data was collected
and processed to 2.3 Å from a native crystal. The crystal belonged to
space group P212121, with the unit cell parameters a = 52.7, b = 54.0,
c = 64.7 Å. Assuming the presence of two molecules in the
asymmetric unit, the Matthews coefficient value is 1.94 Å3 Da-1,
which corresponds to a solvent content of 36.5%. The overall
structure of MinCN is observed as a dimer form through anti-parallel
ß-strand interaction.
Abstract: The aim of the study was to investigate phytochemical
properties, antimicrobial activity and cytotoxicity of Aloe vera. The
phytochemical screening of the extracts of leaves of A. vera revealed
the presence of bioactive compounds such as alkaloids, tannins,
flavonoids phenolic compounds, and etc. with absence of cyanogenic
glycosides. Three different solvents such as methanol, ethanol and
Di-Methyl sulfoxide were used to screen the antimicrobial activity of
A. vera leaves against four human clinical pathogens by agar well
diffusion method. The maximum antibacterial activities were
observed in methanol extract followed by ethanol and Di-Methyl
sulfoxide. It was also found that remarkable antibacterial activities
with methanolic and ethanolic extracts of A. vera compared with the
standard antibiotic, tetracycline that was not active against E. coli
and S. boydii and supported the view that A. vera is a potent
antimicrobial agent compared with the conventional antibiotic.
Moreover, the brine shrimps (Artemia salina) toxicity test exhibited
LC50 value was 569.52 ppm. The resulting data indicated that the A.
vera plant have less toxic effects on brine shrimp. Hence, it is
signified that Aloe vera plant extract is safe to be used as an
antimicrobial agent.
Abstract: This study was conducted to investigate the incidence
of pathogenic bacteria: Salmonella, Shigella, Escherichia coli O157
and Staphylococcus aureus in cakes and tarts collected from thirtyfive
confectionery producing and selling premises located within
Tripoli city, Libya. The results revealed an incidence of S. aureus
with 94.4 and 48.0 %, E. coli O157 with 14.7 and 4.0 % and Salmonella
sp. with 5.9 and 8.0 % in cakes and tarts samples respectively;
while Shigella was not detected in all samples. In order to determine
the source of these pathogenic bacteria, cotton swabs were taken
from the hands of workers on the production line, the surfaces of
preparation tables and cream whipping instruments. The results
showed that the cotton swabs obtained from the hands of workers
contained S. aureus and Salmonella sp. with an incidence of 42.9 and
2.9 %, the cotton swabs obtained from the surfaces of preparation
tables 22.9 and 2.9 % and the cotton swabs obtained from the cream
whipping instruments 14.3 and 0.0 % respectively; while E. coli
O157 and Shigella sp. were not detected in all swabs. Additionally,
other bacteria were isolated from the hands of workers and the Surfaces
of producing equipments included: Aeromonas sp., Pseudomonas
sp., E. coli, Klebsiella sp., Enterobacter sp., Citrobacter sp.,
Proteus sp., Serratia sp. and Acinetobacter sp. These results indicate
that some of the cakes and tarts might pose threat to consumer's
health. Meanwhile, occurrences of pathogenic bacteria on the hands
of those who are working in production line and the surfaces of
equipments reflect poor hygienic practices at most confectionery
premises examined in this study. Thus, firm and continuous surveillance
of these premises is needed to insure the consumer's health and
safety.
Abstract: Taking into account the importance of Lake Sevan and
Lake Sevan basin-s rivers for Armenian economy, the main goals of
our investigations were the documentation of water quality and the
biodiversity of invertebrates developed in Lake Sevan basin-s rivers
and selected tributaries.
Moderately satisfied ecological condition for the biodiversity of
Lake Sevan basin-s rivers has been established, and the changes in
species- composition of zoobenthos in Lake Sevan were detected.
A growing tendency of antibiotic resistance among E. coli isolates
in water resources has been shown.
Abstract: D-erythro-cyclohexylserine (D
chiral unnatural β-hydroxy amino acid expected for the synthesis of drug for AIDS treatment. To develop a continuous bioconversion
system with whole cell biocatalyst of D-threonine aldolase (D genes for the D-erythro-CHS production, D-threonine aldolase gene
was amplified from Ensifer arboris 100383 by direct PCR amplication using two degenerated oligonucleotide primers designed based on
genomic sequence of Shinorhizobium meliloti
Sequence analysis of the cloned DNA fragment revealed one
open-reading frame of 1059 bp and 386 amino acids. This putative
D-TA gene was cloned into NdeI and EcoRI (pEnsi
His-tag sequence or BamHI (pEnsi-DTA[2])
sequence of the pET21(a) vector. The expression level of the cloned gene was extremely overexpressed by E. coli BL21(DE3) transformed with pEnsi-DTA[1] compared to E. coli BL21(DE3) transformed with
pEnsi-DTA[2]. When the cells expressing the wild
used for D-TA enzyme activity, 12 mM glycine was successfully
detected in HPLC analysis. Moreover, the whole cells harbouring the
recombinant D-TA was able to synthesize D-erythro
of 0.6 mg/ml in a batch reaction.
Abstract: Urinary Tract Infections (UTI) account for an estimated 25-40% nosocomial infection, out of which 90% are associated with urinary catheter, called Catheter associated urinary tract infection (CAUTI). The microbial populations within CAUTI frequently develop as biofilms. In the present study, microbial contamination of indwelling urinary catheters was investigated. Biofilm forming ability of the isolates was determined by tissue culture plate method. Prevention of biofilm formation in the urinary catheter by Pseudomonas aeruginosa was also determined by coating the catheter with some enzymes, gentamycin and EDTA. It was found that 64% of the urinary catheters get contaminated during the course of catheterization. Of the total 6 isolates, biofilm formation was seen in 100% Pseudomonas aeruginosa and E. coli, 90% in Enterococci, 80% in Klebsiella and 66% in S. aureus. It was noted that the biofilm production by Pseudomonas was prolonged by 7 days in amylase, 8 days in protease, 6 days in lysozyme, 7days in gentamycin and 5 days in EDTA treated catheter.
Abstract: Information regarding early onset neonatal sepsis
(EONS) pathogens may vary between regions. Global perspectives
showed Group B Streptococcal (GBS) as the most common causative
pathogens, but the widespread use of intrapartum antibiotics has
changed the pathogens pattern towards gram negative
microorganisms, especially E. coli. Objective of this study is to
describe the pathogens isolated, to assess current treatment and risk
of EONS. Records of 899 neonates born in three General Hospitals
between 2009 until 2012 were retrospectively reviewed. Proven was
found in 22 (3%) neonates. The majority was isolated with gram
positive organisms, 17 (2.3%). All grams positive and most gram
negative organisms showed sensitivity to the tested antibiotics. Only
two rare gram negative organisms showed total resistant. Male was
possible risk of proven EONS. Although proven EONS remains
uncommon in Malaysia, nonetheless, the effect of intrapartum
antibiotics still required continuous surveillance.