Patterns of epipelic diatoms and oxygen distributions in stream sediments

Depth distributions of epipelic diatoms and dissolved oxygen in agricultural stream sediments were studied. The major fraction of the diatoms were found in the top 2 cm of sediment. The distribution of diatoms and dissolved oxygen are influenced by each other. Larger numbers of cells were found at depths where oxygen concentrations were high. However, dissolved oxygen profiles measured in situ indicated that a large part of the sediment where viable cells are found is anoxic. In most cases anaerobic conditions exist below 7 and 4 mm depth during day and night respectively. Laboratory experiments suggested that under anaerobic conditions not only was there no evidence of growth but also that mortality increased with increasing depth;In contrast to lake and marine sediments diurnal migration patterns were not observed in this study. Migration and distribution patterns may have been strongly influenced by the more turbulent nature of the stream environment. Great numbers of cells might be lost from their site of production and rates of production might be much higher than would be indicated by the low cell densities routinely observed in situ. Daytime population densities were much higher than nighttime. These differences in population densities were due to a balance of growth, mortality, and loss of cells from the site of production

Tecnología de semillas sintéticas para la encapsulación y el recrecimiento de puntas de brotes y embriones somáticos de Espárrago officinalis L

Apical buds obtained from Asparagus plant vitro culture and somatic embryos obtained from stem cultivation, explants in MS medium supplemented with mg¹ᶫ 1, 2, 4-D and mg¹ᶫ 1 and Kinetin have been used in this research to produce artificial seeds. We encapsulated apical buds and somatic embryo using 2% sodium alginate and calcium chloride to prepare the artificial seeds. We placed artificial seeds at room temperature (about 25 ° C), in the cold, the temperature of 4 ° C and -18 ° C for different times (15,30,60,90 days) and evaluated the growing power of these seeds in MS and ½MS mediums for further investigations about the viability of seeds. The highest conversion percentage of seedlings in encapsulated embryos (70.01) was related to seed harvested from embryos treated with BA and the highest conversion percentage of seedlings in apical buds (96.54) was obtained from cultivated untreated seeds in MS medium. Encapsulated arteries and buds maintained germination energy and viability with increasing storage time after 90 days of storage at 4 and 25 ° C despite viability reduction while un-capsulated embryos and buds completely lost viability after 60 days of storage at 4 and 25 ° C and seeds stored at -18 ° C completely lost viability after 15 days of storage. In general, the percentage of seed germination and conversion to seedling is higher in seeds cultivated in MS medium compared to seeds cultivated in ½MS medium.En esta investigación se han utilizado yemas apicales obtenidas de cultivo vitro vegetal de espárragos y embriones somáticos obtenidos del cultivo de tallos, explantes en medio MS suplementado con mg¹ᶫ 1, 2, 4-D y mg¹ᶫ 1 y Kinetin para producir semillas artificiales. Encapsulamos yemas apicales y embriones somáticos utilizando alginato de sodio al 2% y cloruro de calcio para preparar las semillas artificiales. Colocamos semillas artificiales a temperatura ambiente (alrededor de 25 ° C), en el frío, la temperatura de 4 ° C y -18 ° C para diferentes tiempos (15,30,60,90 días) y evaluamos el poder de crecimiento de estas semillas. en medios MS y ½MS para futuras investigaciones sobre la viabilidad de las semillas. El mayor porcentaje de conversión de plántulas en embriones encapsulados (70.01) se relacionó con la semilla recolectada de embriones tratados con BA y el mayor porcentaje de conversión de plántulas en yemas apicales (96.54) se obtuvo de semillas cultivadas sin tratar en medio MS. Las arterias y las yemas encapsuladas mantuvieron la energía de germinación y la viabilidad con un mayor tiempo de almacenamiento después de 90 días de almacenamiento a 4 y 25 ° C a pesar de la reducción de la viabilidad, mientras que los embriones y las yemas no encapsulados perdieron completamente la viabilidad después de 60 días de almacenamiento a 4 y 25 ° C y las semillas almacenado a -18 ° C perdió completamente la viabilidad después de 15 días de almacenamiento. En general, el porcentaje de germinación de semillas y conversión a plántula es mayor en semillas cultivadas en medio MS en comparación con semillas cultivadas en medio ½MS

Tecnología de semillas sintéticas para la encapsulación y el recrecimiento de puntas de brotes y embriones somáticos de Espárrago officinalis L

Apical buds obtained from Asparagus plant vitro culture and somatic embryos obtained from stem cultivation, explants in MS medium supplemented with mg¹ᶫ 1, 2, 4-D and mg¹ᶫ 1 and Kinetin have been used in this research to produce artificial seeds. We encapsulated apical buds and somatic embryo using 2% sodium alginate and calcium chloride to prepare the artificial seeds. We placed artificial seeds at room temperature (about 25 ° C), in the cold, the temperature of 4 ° C and -18 ° C for different times (15,30,60,90 days) and evaluated the growing power of these seeds in MS and ½MS mediums for further investigations about the viability of seeds. The highest conversion percentage of seedlings in encapsulated embryos (70.01) was related to seed harvested from embryos treated with BA and the highest conversion percentage of seedlings in apical buds (96.54) was obtained from cultivated untreated seeds in MS medium. Encapsulated arteries and buds maintained germination energy and viability with increasing storage time after 90 days of storage at 4 and 25 ° C despite viability reduction while un-capsulated embryos and buds completely lost viability after 60 days of storage at 4 and 25 ° C and seeds stored at -18 ° C completely lost viability after 15 days of storage. In general, the percentage of seed germination and conversion to seedling is higher in seeds cultivated in MS medium compared to seeds cultivated in ½MS medium.En esta investigación se han utilizado yemas apicales obtenidas de cultivo vitro vegetal de espárragos y embriones somáticos obtenidos del cultivo de tallos, explantes en medio MS suplementado con mg¹ᶫ 1, 2, 4-D y mg¹ᶫ 1 y Kinetin para producir semillas artificiales. Encapsulamos yemas apicales y embriones somáticos utilizando alginato de sodio al 2% y cloruro de calcio para preparar las semillas artificiales. Colocamos semillas artificiales a temperatura ambiente (alrededor de 25 ° C), en el frío, la temperatura de 4 ° C y -18 ° C para diferentes tiempos (15,30,60,90 días) y evaluamos el poder de crecimiento de estas semillas. en medios MS y ½MS para futuras investigaciones sobre la viabilidad de las semillas. El mayor porcentaje de conversión de plántulas en embriones encapsulados (70.01) se relacionó con la semilla recolectada de embriones tratados con BA y el mayor porcentaje de conversión de plántulas en yemas apicales (96.54) se obtuvo de semillas cultivadas sin tratar en medio MS. Las arterias y las yemas encapsuladas mantuvieron la energía de germinación y la viabilidad con un mayor tiempo de almacenamiento después de 90 días de almacenamiento a 4 y 25 ° C a pesar de la reducción de la viabilidad, mientras que los embriones y las yemas no encapsulados perdieron completamente la viabilidad después de 60 días de almacenamiento a 4 y 25 ° C y las semillas almacenado a -18 ° C perdió completamente la viabilidad después de 15 días de almacenamiento. En general, el porcentaje de germinación de semillas y conversión a plántula es mayor en semillas cultivadas en medio MS en comparación con semillas cultivadas en medio ½MS

Novel report of the phytochemical composition from Fraxinus excelsior pollen grains

In this research, we investigated the phytochemical profiles for two models of aqueous (Aq) and methanolic (Me) pollen extracts of F. excelsior from three pollination periods from hermaphrodite flowers (H) of polygamous and male flowers of pure male (M) in order to identify their constituent compounds. Pollens of both phenotypes H and M were collected during three pollination periods and were analyzed by light and scanning electron microscopy (LM/SEM). The total phenolic content (TPC) and flavonoids content (TFC) was measured using Folin-Ciocalteu and aluminum chloride (AlCl3) methods, respectively. Antioxidant activities were evaluated using ferric reducing antioxidant power (FRAP) and scavenging free radical DPPH• and ABTS•+. GC-FID and GC/MS were used to identify the chemical composition of essential oils. There was a significant difference (P < 0.001) between the means of TPC for M and TFC for the H. Comparison of H and M antioxidant activities showed that DPPH (IC50) to be (2.977 ± 0.117 μM) during the second pollination period of M and (4.877 ± 0.021 μM) for first period of H. The majority of the compounds identified were linalool (35.42%) from the monoterpenoides in H and Delta-cadinene (43.22%) belonging to the sesquiterpenes in M. We concluded that there is a significant difference between the H and M compounds in pollen at different periods

Patterns of epipelic diatoms and oxygen distributions in stream sediments

Depth distributions of epipelic diatoms and dissolved oxygen in agricultural stream sediments were studied. The major fraction of the diatoms were found in the top 2 cm of sediment. The distribution of diatoms and dissolved oxygen are influenced by each other. Larger numbers of cells were found at depths where oxygen concentrations were high. However, dissolved oxygen profiles measured in situ indicated that a large part of the sediment where viable cells are found is anoxic. In most cases anaerobic conditions exist below 7 and 4 mm depth during day and night respectively. Laboratory experiments suggested that under anaerobic conditions not only was there no evidence of growth but also that mortality increased with increasing depth;In contrast to lake and marine sediments diurnal migration patterns were not observed in this study. Migration and distribution patterns may have been strongly influenced by the more turbulent nature of the stream environment. Great numbers of cells might be lost from their site of production and rates of production might be much higher than would be indicated by the low cell densities routinely observed in situ. Daytime population densities were much higher than nighttime. These differences in population densities were due to a balance of growth, mortality, and loss of cells from the site of production.</p

Cloning, Expression and Characterization of PprI gene in Escherichia coli

Background and Objectives: PprI is one of newly gene identified in Deinococcus radiodurans and plays a critical role in DNA repair and protection against ultraviolet radiation stress. The aim of this study was to clone, express and characterize PprI gene in Escherichia coli.Materials and Methods: The PprI gene of D. radiodurans was constructed in pGEM-B1 vector and the cloned gene was subcloned into pET21a expression vector. The pET21a-PprI was expressed in E. coli (Origami strain). Expression of recombinant PprI was confirmed by SDS-PAGE gel electrophoresis and western blotting. In addition, the UV-C radiation resistance of recombinant E. coli was determined.Results: The chimeric pET21a plasmid containing the C -terminal fusion of His-tag with PprI gene was successfully constructed and the medium condition for the expression was optimized. In addition, transformed E. coli had higher resistance to radiation than the original strain. Conclusion: The results of this study indicated that PprI protein could be a potential candidate to be considered as a radioresistant protein. However, the UV-C radioresistance potency of recombinant PprI should be analyzed in prokaryotic and eukaryotic system

Dionysia robusta (Primulaceae), a new species from W Iran

A new species from the W part of the Iranian Zagros Mountains in Ilam province, Dionysia robusta (Primulaceae), is described, illustrated and compared with similar and related species. It differs from these relatives in leaf shape, length and density of glandular hairs, and shape of the calyx. The DNA sequence of the nuclear ribosomal ITS region of D. robusta is most similar to that of D. gaubae