967 research outputs found
Apex Exponents for Polymer--Probe Interactions
We consider self-avoiding polymers attached to the tip of an impenetrable
probe. The scaling exponents and , characterizing the
number of configurations for the attachment of the polymer by one end, or at
its midpoint, vary continuously with the tip's angle. These apex exponents are
calculated analytically by -expansion, and numerically by simulations
in three dimensions. We find that when the polymer can move through the
attachment point, it typically slides to one end; the apex exponents quantify
the entropic barrier to threading the eye of the probe
Evaluation of in vitro antiviral activity of a brown alga (Cystoseira myrica) from the Persian Gulf against herpes simplex virus type 1
The hot water extract of a brown marine alga, Cystoseira myrica, from the Persian Gulf was evaluated as an antiviral compound against KOS strain of HSV-1 in cell culture. The extract exhibited antiviralactivity against herpes simplex virus type 1 (HSV-1) not only during absorption of virus to the cells, but also on post attachment stages of virus replication. The water extract of C. myrica was sterilized byfiltration and autoclaving, respectively. The IC50 for filtered extract was 99 ìg/ml and the IC50 for autoclaved extract was 125 ìg/ml. Based on resulted selectivity index (SI) values of the extracts, whichwere 33.4 and 28.2 for filtered and autoclaved extracts, respectively, we found that the antiviral compound(s) in the water extract of C. myrica to be heat stable. Also, the SI values for inhibition of thepost attachment stages of HSV-1 replication were 23.1 and 21.7 for filtered and autoclaved extracts, respectively. The IC50 in this phase of study were 143 and 162 ìg/ml for filtered and autoclaved extracts,respectively. Therefore, C. myrica could be a good candidate as a natural source for anti-HSV-1 compound(s) isolation
Antiviral activity of Aloe vera against herpes simplex virus type 2: An in vitro study
In this study we tested the antiviral activity of a crude hot glycerine extract of Aloe vera gel which was grown in Bushehr (Southwest of Iran) against HSV-2 replication in Vero cell line. The extract showedantiviral activity against HSV-2 not only before attachment and entry of virus to the Vero cells but also on post attachment stages of virus replication. The IC50 before attachment and entry of virus to the cellsis 428 ìg/ml and the CC50 value which is the cytotoxicity of the extract for Vero cells is 3238 ìg/ml, while the calculated selectivity index (SI) is 7.56. Also, IC50 of extract on post attachment stages of replicationis 536 ìg/ml and the SI value for inhibition of the post attachment stages of HSV-2 replication is 6.04. Therefore, compounds of Aloe vera from Bushehr could be a good candidate as a natural source for antiviral drug development against HSV-2
Life cycle information from a Wisconsin poplation of Porcellio spinicoris, the dark-headed isopod
Detailed life cycle information is lacking for Wisconsin terrestrial isopod crustaceans. We measured head-widths of a local population of Porcellio spinicornis and compiled data on size frequencies, sex ratio and gravidity. Females were larger and formed a majority of the population. Gravidity showed a definite seasonal pattern; percentages of gravid females ranged from zero in March and April to near 80% in late May and early June
Implementation and modeling of a femtosecond laser-activated streak camera
8 June 2017) A laser-activated streak camera was built to measure the duration of femtosecond electron pulses. The streak velocity of the device is 1.89 mrad/ps, which corresponds to a sensitivity of 34.9 fs/pixels. The streak camera also measures changes in the relative time of arrival between the laser and electron pulses with a resolution of 70 fs RMS. A full circuit analysis of the structure is presented to describe the streaking field and the general behavior of the device. We have developed a general mathematical model to analyze the streaked images. The model provides an accurate method to extract the pulse duration based on the changes of the electron beam profile when the streaking field is applied
Anticancer activity of Sargassum oligocystum water extract against human cancer cell lines
Background and Objectives:
Antitumor drug resistance and side effects of
antitumor compounds are the most common
problems in medicine. Therefore, finding new
antitumor agents with low side effects could be
interesting. This study was designed to assay
antitumor activity of the extract from brown alga
Sargassum oligocystum, gathered from Persian
Gulf seashore, against K562 and Daudi human
cancer cell lines.
Materials and Methods: The research was
performed as an in vitro study. The effect of
the alga extract on proliferation of cell lines
were measured by two methods: MTT assay
and trypan blue exclusion test.
Results and Conclusion: The most effective
antitumor activity has been shown at concentrations
500 μg/ml and 400 μg/ml of the alga
extract against Daudi and K562 cell lines,
respectively. The results showed that the extracts
of brown alga Sargassum oligocystum
have remarkable antitumor activity against
K562 and Daudi cell lines. It is justified to be
suggested for further research such as algal
extract fractionation and purification and in vivo
studies in order to formulate natural compounds
with antitumor activities
In vitro antitumor activity of Gracilaria corticata (a red alga) against Jurkat and molt-4 human cancer cell lines
Gracilaria corticata is a red alga which can be collected from many sea coasts around the world such as China, India, Persian Gulf, etc. The Persian Gulf is a unique marine habitat infested with diverse seaweeds. The aim of the present study is to explore anticancer potential of the crude extracts from G. corticata which was collected from the Bushehr coast (South west of Iran). Here, different concentration of the aqueous extract from G. corticata was tested for probable antitumoral activity on Jurkat and molt- 4 human lymphoblastic leukemic cell lines. The cells were treated by different concentration of algal extract and the number of viable cells was determined by trypan blue. Also, cytotoxicity of the extract was evaluated by methyl thiazolyl tetrazolium (MTT) assay. The results showed that 9.336 and 9.726 μg/μl of algal extract were the most effective concentrations against Jurkat and molt-4 cells, respectively. The water crude extract of red alga G. corticata had significant anticancer activity and it might be a good candidate for further investigations in order to develop a natural compound as an anticancer agent which can be used for the production of potential anticancer drug and novel pharmaceutical leads.Key words: Gracilaria corticata, anticancer, Jurkat, molt-4
Isolation of a 60 kDa protein with in vitro anticancer activity against human cancer cell lines from the purple fluid of the Persian Gulf sea hare, Aplysia dactylomela
Sea hares have greatly attracted the interest of all those investigating chemical defense substances. Most of these substances are low molecular weight compounds derived from algal diets. In vitroanticancer effect of a 60 kDa protein isolated from the purple fluid of Aplysia dactylomela on four human cancer cell lines was investigated in this study. A 60 kDa protein was purified from secreted purple fluid of A. dactylomela, a sea hare from Persian Gulf. The protein purification procedure consisted basically of ammonium sulfate precipitation, ion exchange chromatography using DEAE– Sepharose and ultra-filtration method. In vitro antiproliferative and cytotoxic activity of the protein ofinterest were evaluated on L929, K562, HL60 and NB4 human cancer cell lines. The antiproliferative and cytotxic effects of 60 kDa protein on human cancer cell lines were measured by MTT assay. Resultsshowed that the 60 kDa protein of the purple fluid of A. dactylomela exhibited the antiproliferative effect on human cancer cell lines, especially on NB4 cell line. It was maximally active at 0.5 – 1.5 ìg/ml on NB4 cell line. Interestingly, the protein did not show significant cytotoxic effects
Antiviral activity of Holothuria sp. a sea cucumber against herpes simplex virus type 1 (HSV-1)
BACKGROUND: Finding the new
bioactive compounds with antiviral activity from
the natural resources are in interest of many drug
discovery scientists. Sea cucumber is among the
marine organisms a traditional food item in Asia
with different applications in traditional medicine.
METHODS: In current study, a cold water extract
of the Holothuria sp, one type Persian Gulf’s
sea cucumber was evaluated for its antiviral effects
against KOS strain of Herpes Simplex Virus
tyoe 1 (HSV-1) in cell culture. The half maximal inhibitory
concentration (IC50) values were calculated
for anti-adsorption activity and intracellular antiviral
activity of the crude extract separately.
RESULTS: The extract exhibited antiviral activity
not only against the virus adsorption to the cells,
but also on virus intracellular replication.The CC50
for sea cucumber extract was 32.57 mg/ml. The
IC50 values for the inhibition of the virus adsorption
to the cells and virus intracellular replication
were 120.2 and 189.9 μg/ml respectively. Selectivity
index (SI) value for anti-adsorption activity was
189 while that value for the extract’s intracellular
antiviral activity was 172.
CONCLUSIONS: The results showed that
Holothuria sp, water extract has remarkable antiviral
effect against HSV-1 in cell culture and it
is crucial to investigate the mechanism(s) of action
of extract. Moreover, identification of the effective
compound(s) within the extract would be
necessary for future studies towards developing
the new natural antiviral agent against HSV-1
Molecular epidemiology of hepatitis C virus genotypes in Bushehr province, Iran
Background and Objectives:
Molecular epidemiology of hepatitis C virus
(HCV) is very important for the treatment of hepatitis
C infection. The aim of this study was to
determine the distribution of HCV genotypes in
Bushehr province (South West of Iran).
Materials and Methods: A total of 100 patients
who were detected as positive for HCV antibody
(by using ELISA method and RIBA test)
referred to Arya Virology Laboratory between
2007-2009 in order to molecular diagnosis and
furthermore virus genotyping. After detection of
HCV, RNA genotyping of virus was done by using
genotype specific primers.
Results: Genotype 1a was found in 49% of
the patients and genotype 3a was found in 40%
of the patients and 1b in 5% of patients, while
the genotype of the virus could not be identified
in 5% of the patients. Finally, in 1% of patients
coinfection due to 1a-3a genotypes was
identified.
Conclusion: The dominant genotype of HCV
in Bushehr province, Iran, was determined as 1a.with acute hepatitis C ultimately develop chronic
infection1. Only a minority of cases of acute
HCV recover completely, with spontaneous virus
eradication. In most cases the acute infection
progresses to chronicity. Chronic HCV infection
is defined as an infection that persists for more
than 6 months, with or without clinical manifestations
of hepatic or extrahepatic disease. Chronic
type of this infection can cause cirrhosis, liver
failure, and liver cancer. HCV infection is a global
health problem and it is estimated that 200
million people of the world population are infected5.
The global spread of chronic HCV infection
coincided with the widespread use of transfused
blood and blood products and with the expansion
of intravenous drug use but decreased prior to the
wide implementation of anti-HCV screening6.
There are at least six major genotypes designated
by Arabic numerals and more than 50 subtypes
of HCV identified by lower case letters. The different
genotypes have different geographic distributions1,4.
Genotype determination of HCV is
one of the most important factors in order to prediction
of the viral persistency, pathogenicity and
resistancy to antivirals7. The success and the
treatment period of interferon and ribavirin
seems to be related to the genotype of virus8.
Furthermore, HCV genotyping is a useful tool to
determine its molecular epidemiology, as they
are indicative of transmission route of infection9,10.
There is no published data about the distribution
of HCV genotypes from Bushehr
province (South West of Iran). Prevalence of
HCV genotypes in Bushehr is an issue that is not
sufficiently investigated and there is a need,
therefore, to study this in detail
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