Journal of Cell and Molecular Research
Volume:4 Issue: 1, Summer and Autumn 2012

TRR14 is a novel protein important in trehalose (α-D-glucosyl-[1,1]-α-D-glucopyranoside) signaling in Arabidopsis. In this research, we provided evidences to demonstrate that TRR14 plays role in Arabidopsis responses to salt and drought stress. The transgenic Arabidopsis plants over-expressing TRR14 under the control of CaMV 35S promoter were generated. Transformed lines showed higher transcript levels of TRR14 than that of Wild Type (WT) Arabidopsis plants. The RT-PCR results showed that TRR14 transcript level increased markedly by salt and drought stress both in WT and transformed lines. Further experiments indicated that the TRR14 transformed lines have unchanged seed germination, root length and chlorophyll content under stress conditions. In addition activity of oxidative enzymes like peroxidase and catalase were significantly induced in tranformed lines under salt and drought treatments. Thus, the present data indicate that a novel protein, TRR14, is involved in plant salt and drought tolerance.

The exact developmental origin of microglia is still under debate. In the present study we investigated which heamatopoietic tissues and which features of the organotypic brain slice culture promoted microglia ramification. The potential of cells derived from embryonic yolk sac, embryonic aorta-gonad- esonephros and adult blood monocytes was examined. These tissues were co-cultured with brain slices after the brain slices had first been maintained in vitro for 1 day, 5 days and 9 days. When brain slices had been maintained in culture for 1 day before the donor cells were added, the donor cells took several days to ramify. However, when donor tissues were added to brain slices that had been 5 or 9 days maintained in culture, the donor cells exhibited a ramified morphology within a day. Therefore changes in organotypic brain slices had an effect on the transformation of cells to the microglial morphology. When adult blood monocytes were added to brain slice cultures there was no evidence of any tendency to ramify over 6 days of co-culture. This study did not support the suggestion that microglia cells derive from bone-marrow (BM) cells or from circulating monocytes.

Bacteria play a major role in environmental processes. However, the spatial and seasonal variations and environmental impact factors on different bacterial groups have been poorly studied. In the present study, we compared the spatial and seasonal variations of two bacterial groups (Acidobacteria, Actinobacteria) from Early Snow Melt and Late Snow Melt locations in Alpine tundra. The results revealed that pH is the essential factor for structuration of two bacterial groups. The pattern of Acidobacteria is very similar to the overall bacterial communities in our previous study, while both bacterial communities are highly influenced by seasonal variations with an independent pattern.

StrR is a putative pathway specific regulator of streptomycin production in Streptomyces griseus. Because of finding new spo0j domain in strR by bioinformatics methods, the purpose of this study was to suggest another role for strR gene. This domain can be seen in proteins that are involved in initiation of sporulation and normal chromosome partitioning. So, 51 bps of strR in accordance to spo0j domain was deleted to investigate effects of deletion mutation in StrR functions. A unique specific procedure, including three consecutive PCRs known as SOEing PCR has been correctly used for site directed mutagenesis. Application and feasibility of this PCR was studied here. Bioinformatics studies were carried out for comparison of the sequences similarities between StrR and Spo0J proteins. A unique specific procedure, including three consecutive PCRs, was design here in order to delete a 51 bp from the native strR. Other PCRs such as Semi-Nested PCR and RFLP PCR were used for strR isolation and structural confirmation of the isolated strR and deleted strR genes. Routine genetic engineering procedures were conducted in order to clone the native and deleted strR genes into E. coli. Obtained sequence information, from Conserved Domains Database (CDD) and Clustal W program, has revealed that the StrR is similar to members of ParB family. Here, the strR was initially isolated from Iranian strain of S. griseus (PTCC1127). It was then confirmed as StrR by Semi-Nested PCR and RFLP-PCR. A 51 base pair region of strR gene was deleted by specifically designed overlapped primers. A ten nucleotide overlap region was considered for a set of these primers. The recombinant cassette pSPMstrRΔ17 was constructed and cloned in E. coli. The sequencing results showed that a specific deletion is produced in the desired site and region in the strR gene. Therefore the designed three steps PCRs (known as SOing PCR) is a very rapid, cheap and precise method for introducing such a deletion in any preferred gene.

In this study proline content and activity of catalase (CAT), and ascorbate peroxidase (APX) and level of lipid peroxidation in terms of malondialdehyde (MDA) content were measured in transgenic tobacco (Nicotiana tabacum cv. Wisconsin), over expressing a Δ-1-pyrroline-5-carboxylate synthase (P5CS) gene, and non transgenic plants as control. Drought stress was applied using polyethylene glycol (PEG) 6000 at concentrations of 217, 264, 320, 637, 1292 mmol/kg equal to (0, 5, 10, 20, 30% respectively). Proline content, especially in transgenic plants, was increased in leaves and roots significantly. CAT and APX activities increased under drought stress and the highest activity was observed in 10 and 20% of the PEG treatment. MDA content was increased by increasing of PEG and the highest MDA content was revealed in transgenic and non transgenic plants at 20% and 30%, respectively. Our results suggest that P5CS is an inducible gene and over production of proline and induction of CAT and APX activities are involved in drought tolerance mechanism.