In vivo assembly of a truncated H subunit mutant of the Rhodobacter sphaeroides photosynthetic reaction centre and direct electron transfer from the QA quinone to an electrode.

We address a challenge in the engineering of proteins to redirect electron transfer pathways, using the bacterial photosynthetic reaction centre (RC) pigment-protein complex. Direct electron transfer is shown to occur from the QA quinone of the Rhodobacter sphaeroides RC containing a truncated H protein and bound on the quinone side to a gold electrode. In previous reports of binding to the quinone side of the RC, electron transfer has relied on the use of a soluble mediator between the RC and an electrode, in part because the probability of QB quinone reduction is much greater than that of direct electron transfer through the large cytoplasmic domain of the H subunit, presenting a ~ 25 Å barrier. A series of C-terminal truncations of the H subunit were created to expose the quinone region of the RC L and M proteins, and all truncated RC H mutants assembled in vivo. The 45M mutant was designed to contain only the N-terminal 45 amino acid residues of the H subunit including the membrane-spanning α-helix; the mutant RC was stable when purified using the detergent N-dodecyl-ß-D-maltoside, contained a near-native ratio of bacteriochlorophylls to bacteriopheophytins, and showed a charge-separated state of [Formula: see text]. The 45M-M229 mutant RC had a Cys residue introduced in the vicinity of the QA quinone on the newly exposed protein surface for electrode attachment, decreasing the distance between the quinone and electrode to ~ 12 Å. Steady-state photocurrents of up to around 200 nA/cm2 were generated in the presence of 20 mM hydroquinone as the electron donor to the RC. This novel configuration yielded photocurrents orders of magnitude greater than previous reports of electron transfer from the quinone region of RCs bound in this orientation to an electrode.

The Anti-apoptotic Mechanism of Metformin Against Apoptosis Induced by Ionizing Radiation in Human Peripheral Blood Mononuclear Cells.

BACKGROUND: In a previous article, we showed that metformin (MET) can reduce ionizing radiation (IR) induced apoptosis in human peripheral blood mononuclear cells. However, the anti-apoptotic mechanism of MET against IR remains unclear. The present study attempts to investigate the mechanism of action of MET in limiting X-ray induced apoptosis in human peripheral blood mononuclear cells. MATERIAL AND METHODS: Mononuclear cells were treated with MET for 2 hours and irradiated with 6 MV X-rays. The gene expression levels of BAX, CASP3 and BCL2 were determined 24 hours post irradiation using real time quantitative polymerase chain reaction (qPCR) technique. Furthermore, the protein levels of BAX, CASP3 and BCL2 were analyzed by Western blotting assay. RESULTS: Radiation exposure increased the expressions of BAX and CASP3 genes, and decreased the expression of BCL2 gene in mononuclear cells. Conversely, an increase in BCL2 gene expression along with a decrease in BAX and CASP3 genes expression was observed in MET plus irradiated mononuclear cells. It was found that radiation increased BAX/BCL2 ratio, while MET pretreatment reduced these ratios. Also, treatment with MET without irradiation did not change the expressions of BAX, CASP3 and BCL2 genes. On the other hand, downregulated expression of BCL2 protein and upregulated expressions of BAX and CASP3 proteins were found in 2 Gy irradiated mononuclear cells, while pretreatment with MET significantly reversed this tendency. CONCLUSION: These results suggest that MET can protect mononuclear cells against apoptosis induced by IR through induction of cellular anti-apoptotic signaling.Key words: ionizing radiation - metformin - apoptosis - genes - proteins - blood cells.

Potent radioprotective effects of combined regimens of famotidine and vitamin C against radiation-induced micronuclei in mouse bone marrow erythrocytes.

To investigate the radioprotective effect of the combination of famotidine and vitamin C against radiation-induced micronucleus formation in mouse bone marrow erythrocytes, various doses of famotidine or vitamin C or combinations thereof were administered intraperitoneally to adult male NMRI mice 2 h before 2 and 4 Gy γ-irradiation. The frequency of micronucleated polychromatic erythrocytes (MnPCEs) was scored in 5,000 polychromatic erythrocytes (PCEs), and the cell proliferation ratio [PCE/(PCE + NCE); NCE = normochromatic erythrocytes] was also calculated for each treatment group. Data were statistically evaluated using one-way ANOVA test. The results show that pretreatment with various doses of famotidine and vitamin C before γ-irradiation significantly reduced the frequency of MnPCEs with a protection factor (PF) of 2 and 1.7, respectively. Pretreatment with vitamin C also significantly increased the cell proliferation ratio, while famotidine had no effect. Combination of famotidine and vitamin C was more effective in reducing MnPCEs than each compound alone, leading to a PF of 4.3 after irradiation. Cell proliferation ratio was also significantly improved by the combination compared with the irradiated control groups. Both famotidine and vitamin C are potent scavengers of free radicals and reactive oxygen species, especially OH(·). The combination of the two compounds probably further enhances this activity, thus leading to high bone marrow protection.

Climate effects on the COVID-19 outbreak: a comparative analysis between the UAE and Switzerland.

The main aim of the present study is to disclose the similarities or differences of the climate effects on the COVID-19 outbreak in two countries, which have different climatic conditions. Using the correlation modeling, the results revealed that some climatic factors, such as the ULR, temperature, and CH4 in the UAE and aerosol index and NO2 in Switzerland have positive lagged correlations with the outburst of COVID-19 by intensifying role within - 9, - 7, and - 2 days. The mitigating role was also observed for ozone/solar radiation and temperature/long-wave radiation in the UAE and Switzerland, respectively. The initial hypotheses of the research have confirmed the correlations between new cases of COVID-19 and ULR and aerosol indices in the UAE and Switzerland. However, the main finding revealed that the climate effects on the COVID-19 outbreak show different roles in the different countries, locating in dissimilar climatic zones. Accordingly, the COVID-19 can be intensified by increases of the ULR and temperature in an arid region, while it can be exactly mitigated by increases of these factors in a temperate area. This finding may be useful for future researches for identifying the essential influencing factors for the mitigating COVID-19 outbreak.

The radiotracer (99m)Tc-MIBI is not genotoxic for human peripheral blood lymphocytes at diagnostic radioactive dose.

The radiotracer technetium-99m methoxyisobutyl isonitrile ((99m)Tc-MIBI) has been widely used for myocardial blood flow imaging. We investigated the genotoxicity of (99m)Tc-MIBI in cultured human lymphocytes at the same concentration used in patients. Radioactivity doses were determined in whole blood at 5 min post-injection of 20 mCi (99m)Tc-MIBI in patients. Subsequently, whole blood of human volunteers was incubated with 1, 2.3, 4 or 8 microCi (99m)Tc-MIBI. After a 30-min incubation, the lymphocytes were stimulated with a mitogen to assay for micronuclei in cytokinesis-blocked binucleated cells. The frequency of micronuclei in samples treated with this radiopharmaceutical up to 2-fold (8 microCi) the concentration of (99m)Tc-MIBI normally found in the blood of patients was not more than in control lymphocyte cultures. We concluded that there is no increased induction of micronuclei in lymphocytes incubated with (99m)Tc-MIBI at the radioactivity doses used for diagnostic purposes.

Combined Effect of Iodine Contrast Media, Cisplatin and External Beam Radiotherapy on Anaplastic Thyroid Cancer Cells.

INTRODUCTION: The current study investigated the combination of high Z atoms (iodine-, platinium-based drugs) with using low energy irradiation (120kvp) in Anaplastic Thyroid cancer cells. MATERIAL AND METHODS: For this purpose, eight groups were designed: control (CNT), different concentrations of Iodine contrast media (ICM), irradiation with various doses, Cis-platin (CDDP) with different concentrations, (ICM + CDDP), (ICM + RAD), (CDDP + RAD) and (ICM + CDDP + RAD). The viability was measured by MTT and Colony assay. In MTT assay, the viability of 8305c cells RAD (2 Gy)+ICM (10mg/mL) group was significantly lower than those treated with RAD or ICM alone. CDDP +ICM+RAD group significantly decreased the viability. In colony assay, cells in ICM + RAD (2 Gy) group reduced the number of colonies more significant than RAD group. The difference of colony forming ability between CDDP and CDDP + RAD (2 Gy) was significant. The difference of ICM + CDDP + RAD (2 Gy) and CDDP +RAD (2 Gy) group was significant. All data were statistically analysed using one-way analysis of variance (ANOVA) followed by Chafe's multi-comparisons tests. All data were presented as mean ± standard deviation (SD) and analysed using statistical package for social sciences (SPSS 16). Significance was considered to be p<0.05. RESULTS: In MTT assay, the viability of 8305c cells RAD (2 Gy) + ICM (10mg/mL) group was significantly lower than those treated with RAD or ICM alone. CDDP + ICM + RAD group significantly decreased the viability. In colony assay, cells in ICM + RAD (2 Gy) group reduced the number of colonies more significantly than RAD group. The difference of colony forming ability between CDDP and CDDP + RAD (2 Gy) was significant. The difference of ICM + CDDP + RAD (2 Gy) and CDDP + RAD (2 Gy) group was significant. CONCLUSION: Exposure of ATC to ICM in the presence of CDDP increases tissue X-rays absorbance by Auger electrons and photo electrons leading to more fatal effects against the tumour.

Radioprotective Effects of Sulfur-containing Mineral Water of Ramsar Hot Spring with High Natural Background Radiation on Mouse Bone Marrow Cells.

BACKGROUND: We intend to study the inhibitory effect of sulfur compound in Ramsar hot spring mineral on tumor-genesis ability of high natural background radiation. OBJECTIVE: The radioprotective effect of sulfur compounds was previously shown on radiation-induced chromosomal aberration, micronuclei in mouse bone marrow cells and human peripheral lymphocyte. Ramsar is known for having the highest level of natural background radiation on Earth. This study was performed to show the radioprotective effect of sulfur-containing Ramsar mineral water on mouse bone marrow cells. METHOD: Mice were fed three types of water (drinking water, Ramsar radioactive water containing sulfur and Ramsar radioactive water whose sulfur was removed). Ten days after feeding, mice were irradiated by gamma rays (0, 2 and 4 Gy). 48 and 72 hours after irradiating, mice were killed and femurs were removed. Frequency of micronuclei was determined in bone marrow erythrocytes. RESULTS: A significant reduction was shown in the rate of micronuclei polychromatic erythrocyte in sulfur-containing hot spring water compared to sulfur-free water in hot spring mineral water. Gamma irradiation induced significant increases in micronuclei polychromatic erythrocyte (MNPCE) and decreases in polychromatic erythrocyte/polychromatic erythrocyte + normochromatic erythrocyte ratio (PCEs/PCEs+NCEs) (P < 0.001) in sulfur-containing hot spring water compared to sulfur-free hot spring mineral water. Also, apparently there was a significant difference between drinking water and sulfur-containing hot spring water in micronuclei polychromatic erythrocyte and polychromatic erythrocyte/polychromatic erythrocyte+ normochromatic erythrocyte ratio. CONCLUSION: The results indicate that sulfur-containing mineral water could result in a significant reduction in radiation-induced micronuclei representing the radioprotective effect of sulfur compounds.

Compaction rate of in vitro fertilized bovine embryos related to the interval from insemination to first cleavage.

A study was conducted on early cleavage divisions and timing of compaction in bovine preimplantation-stage embryos. Zygotes were produced using conventional in vitro maturation and fertilization procedures. Twenty hours post insemination, the zygotes were denuded and cultured with oviduct epithelial cells in B2 medium + 10% estrous cow serum. Starting at 24 hours post insemination, the embryos (n=657) were evaluated every 6 hours and then were put into different co-culture drops according to their cell number. Starting from 78 hours post insemination, the cleavage rate was evaluated every 12 hours. Embryos were stained with Hoechst 33342 at the compacted morula stage or when they were degenerated, at 162 hours post insemination. Developmentally capable embryos were characterized by a rapid cleavage rate in the first 3 cell cycles and by an extended 8- to 16-cell stage. Peak concentrations of 2-, 4-, 8- and 16-cell stages emerged at 36, 42, 60 and 102 hours post insemination, respectively. Compaction did not occur until 126 hours post insemination. The rate of compaction was significantly higher in embryos that were at the 2-cell stage before or at 36 hours post insemination (P < 0.05). The mean cell numbers of compacted morulae that were identified at 126 and 138 hours post insemination were 30.9 +/- 6.8 and 31.6 +/- 7.7, respectively. These results indicate that developmentally capable bovine embryos reach the 2-cell stage at 36 hours post insemination, and that they become compacted at the 32-cell stage, which usually occurs between 126 and 138 hours post insemination.

Birth of double-muscled Belgian Blue calves after transfer of in vitro produced embryos into dairy cattle.

The possible application of the bovine in vitro fertilization technique for economical beef production was evaluated by transferring in vitro produced Belgian Blue embryos to synchronized dairy cows and heifers. In total, 4167 oocytes, collected in the slaughterhouse from double-muscled Belgian Blue cows, were matured in vitro. Frozen-thawed semen from 3 Belgian Blue bulls was used for in vitro fertilization. Zygotes were cultured in B(2) + 10% estrous cow serum together with oviductal cells at 39 degrees C in 5% CO(2) in air. After 7 days, 576 (13.8%) transferable embryos were obtained. One hundred and eighteen of the most advanced embryos were selected for fresh transfer into 90 recipients. Some of the remaining embryos were frozen using conventional methods. After fresh transfer, 50 recipients (55.6%) had elevated progesterone at day 23. Thirty cows (33.3%) calved after a mean gestation length of 282.8+/-6.0 days and produced 25 single births and 5 twins. The sex ratio was 71.4%. The mean birth weight was 45.1+/-8.3 kg. Three calves were of the conventional type instead of double-muscled and 2 calves died of congenital malformations. After transfer of in vitro produced frozen-thawed Belgian Blue embryos into 27 recipients (1 embryo/recipient), 2 bull calves (7.4%) were born. Bovine embryo production by in vitro techniques could form a low-cost supply of beef calves. However, to render it commercially attractive, selection of sires and dams has to be performed with great care.

Vegetation cover plays the most important role in soil erosion control.

To obtain, characteristics and behaviors of soil erosion phenomena, to control it's harms and reduce it's risks, realistic data from soil erosion rates are necessary. Mean while, measuring soil erosion rates particularly in large scale is a time consuming and expensive task. Moreover, spatial and temporal changes of soil erosion increase this problem. Therefore, to find out a certain way of creating capable methods which easily and quickly be able to estimate soil erosion rate, is quite logical. So, different models are widely used, but, may be the most important consideration with this regard is that, these models should be previously, tested and adopted to defined areas to stop probability of causing some huge and meaningful errors. Therefore, to achieve the above mentioned aim, different methods are used. Anyway, conditions which resulted to create a suitable model, should be considered in a defined area where, model is applied, unless, model application can leads to huge risks. This study is an attempt with this refer, that is, with comparing measured soil loss rates and predicted soil erosion rates from a defined catchment area, created a reasonable relationship between them and achieved the main aim of the study. That is, one of the small upland catchments of Emam kandi of Urmia with 75 ha area which is part of the Urmia lake catchment area and under layned by calcareous parent material, is selected as a study site. Selected catchment has natural pasture and has closured during the recent years. To calculate sediment yield the following processes were done: first, estimating the volume of trapped sediments, then, surveying the catchment area, for calculating sediment yield. Measured sediment yield is 6.19 t ha(-1) year(-1) which leads to soil loss rate of 13.76 t ha(-1) year(-1) by using Sediment Delivery Ratio (SDR). Also, inside the measurement of sediment yields and calculation of soil loss rates, two models of MUSLE and PSIAC were used respectively after exclosure and before exclosure to predict soil loss rates. Predicted soil loss rates by MUSLE and PSIAC respectively are 12.80 and 26.5 t ha(-1) year(-1). Finally, Comparisons and statistical analysis and scientific discussions were made.

Floristic study of Ghasemloo (Shohada) Valley Forest reserve and adjacent area.

In this survey flora of protected region of Ghasemloo valley Forest reserve and adjacent areas has been studied. The study area includes about 577 ha and is located at south of Urmia. The method which used for plant collection is the same as regional floristic studies. Collected plants were recognized and determined as families, genera and species by using of indispensable references. Alphabetical list of taxa in this region was provided on the base of families, genera and species. The life form of plant species was determined by using of Raunckier's method and chorotype of plant species was determined by indispensable references. In this research 50 family, 165 genera and 204 species were identified. The largest plant family is Compositae with 21 genera and 26 species and the largest genera is Astragalus from Papilionaceae family with 6 species. The main biological forms respectively are: Therophytes and hemichryptophytes. The most extended chorotype with 61.28% is related to Irano-Turanian.

Ecological study in forest reserve of Ghasemloo (Shohada) valley and it's adjacent areas, Urmia-Iran.

Forest reserve of Ghasemloo valley (Shohada) and it's adjacent areas with 577 hectare surface area has located in south of Urmia and is known as an important natural plant station of Urmia. It is studied with respect the important factors which influencing vegetation cover in whole, particularly, with refer to composition and Formation of plant communities. To study the area, Brown-Blanquet's method was used. Plant samples were collected from 77 sample plots. The study resulted in recognition of four herbaceous types and seven shrub communities in study area. In addition, the investigation led to the fact that the most important factors which influencing the vegetation cover, are: geographical orientation, altitude, gradient and soil texture. More over, the study also resulted to preparation ofa colour vegetation map with 1/20000 scale.

Optimization of a simple vitrification procedure for bovine embryos produced in vitro: effect of developmental stage, two-step addition of cryoprotectant and sucrose dilution on embryonic survival.

Experiments were designed to determine optimal conditions for the cryopreservation of bovine embryos produced in vitro. In Expt 1, embryos were exposed for 1, 3 or 5 min to a vitrification solution consisting of 40% (v/v) ethylene glycol, 18% (w/v) Ficoll and 10.26% (w/v) sucrose (EFS) and were subsequently vitrified. After warming in water at room temperature and diluting in a solution of 0.25 mol sucrose l-1, the in vitro survival rate in Ménézo-B2 medium was highest after exposure to EFS for 1 min. In Expt 2, embryos at day 7 and day 8 were vitrified after exposure to EFS for 1 min. The survival rate of embryos at day 7 was significantly improved, especially at the blastocyst and expanded blastocyst stage, when the Ménézo-B2 medium was supplemented with bovine oviduct epithelial cells (BOEC). Embryos at day 8 exhibited a significantly lower survival rate than did embryos at day 7 in both culture media. In Expt 3, one-step exposure of embryos to EFS for 1 min was compared with two-step exposure to 20% ethylene glycol for 3 min and EFS for 30-45 s. Embryos exhibited significantly higher survival and hatching rates after two-step vitrification, especially at the expanded blastocyst (89% and 69%, respectively) and the blastocyst stage (75% and 38%, respectively). In Expt 4, embryos were diluted in solutions of 0, 0.25 or 0.5 mol sucrose l-1 after two-step vitrification. There were no significant differences in the survival rates between the three dilution treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Silicone oil used in microdrop culture can affect bovine embryonic development and freezability.

The effect of silicone and paraffin oil, which is routinely used to overlay in vitro embryo culture media, on bovine in vitro embryonic development and on their subsequent survival after one-step vitrification was investigated. In experiment 1, silicone oil batch 13 was compared with paraffin oil. Embryonic development to the eight-cell and blastocyst stage was significantly impaired by silicone oil batch 13 in comparison with paraffin oil (p < 0.0001). Normal looking blastocysts produced under both types of oil were vitrified. None of the blastocysts that were produced under silicone oil batch 13 survived the vitrification procedure whereas 59% of the blastocysts survived when they were cultured under paraffin oil both before vitrification and after warming. In experiment 2, another batch no. 7 of the same brand of silicone oil was compared with paraffin oil. No effect of the type of oil on embryonic development until the eight-cell stage could be demonstrated. However, the blastocyst formation rate was significantly lower with silicone oil batch 7 than with paraffin oil. The survival of vitrified blastocysts after warming was significantly improved when silicone batch 13 was replaced by batch 7 (0 and 41%, respectively) although it was still lower when compared with the survival of blastocysts developed under paraffin oil (53%) (p < 0.05). In further attempts to find the cause of the problem, the silicone and paraffin oils were analysed for Zn-contents (experiment 3). Zn-contents were comparable for silicone oil batch 13 (0.87 microM), silicone oil batch 7 (0.62 microM) and paraffin oil (0.73 microM). Media, conditioned by bovine oviduct epithelial cells cultured with a silicone or paraffin oil overlay were analysed by means of thin layer chromatography for differences in qualitative fatty acid composition. It was possible to detect that oil overlay changed the relative abundance of fatty acids in the different lipid classes. In the free fatty acid fraction, it was skewed in favour of palmitic acid and in cholesterol esters and phospholipids in favour of linoleic acid. It appears that due to the changed lipid contents of the medium, embryonic membranes are rendered more susceptible to freezing due to altered membrane composition or by membrane damage caused by lipid peroxidation.