Human RECQ1 helicase-driven DNA unwinding, annealing, and branch migration : insights from DNA complex structures

RecQ helicases are a widely conserved family of ATP-dependent motors with diverse roles in nearly every aspect of bacterial and eukaryotic genome maintenance. However, the physical mechanisms by which RecQ helicases recognize and process specific DNA replication and repair intermediates are largely unknown. Here, we solved crystal structures of the human RECQ1 helicase in complexes with tailed-duplex DNA and ssDNA. The structures map the interactions of the ssDNA tail and the branch point along the helicase and Zn-binding domains, which, together with reported structures of other helicases, define the catalytic stages of helicase action. We also identify a strand-separating pin, which (uniquely in RECQ1) is buttressed by the protein dimer interface. A duplex DNA-binding surface on the C-terminal domain is shown to play a role in DNA unwinding, strand annealing, and Holliday junction (HJ) branch migration. We have combined EM and analytical ultracentrifugation approaches to show that RECQ1 can form what appears to be a flat, homotetrameric complex and propose that RECQ1 tetramers are involved in HJ recognition. This tetrameric arrangement suggests a platform for coordinated activity at the advancing and receding duplexes of an HJ during branch migration

Identification of a potent herbal molecule for the treatment of breast cancer

<p>Abstract</p> <p>Background</p> <p>Breast cancer (BCa)-related mortality still remains the second leading cause of cancer-related deaths worldwide. Patients with BCa have increasingly shown resistance and high toxicity to current chemotherapeutic drugs for which identification of novel targeted therapies are required.</p> <p>Methods</p> <p>To determine the effect of PDBD on BCa cells, estrogen-receptor positive (ER⁺)-MCF-7 and estrogen-receptor negative (ER^-)-MDA 231 cells were treated with PDBD and the cell viability, apoptotic, cell cycle, Western blot and Promoter assays were performed.</p> <p>Results</p> <p>PDBD inhibits cell viability of ER⁺and ER^-BCa cells by inducing apoptosis without causing significant toxicity in normal breast epithelial cells. While dissecting the mechanism of action of PDBD on BCa, we found that PDBD inhibits Akt signaling and its downstream targets such as NF-κB activation, IAP proteins and Bcl-2 expression. On the other hand, activation of JNK/p38 MAPK-mediated pro-apoptotic signaling was observed in both ER⁺and ER^-BCa cells.</p> <p>Conclusion</p> <p>These findings suggest that PDBD may have wide therapeutic application in the treatment of BCa.</p

Chickpea

The narrow genetic base of cultivated chickpea warrants systematic collection, documentation and evaluation of chickpea germplasm and particularly wild Cicer species for effective and efficient use in chickpea breeding programmes. Limiting factors to crop production, possible solutions and ways to overcome them, importance of wild relatives and barriers to alien gene introgression and strategies to overcome them and traits for base broadening have been discussed. It has been clearly demonstrated that resistance to major biotic and abiotic stresses can be successfully introgressed from the primary gene pool comprising progenitor species. However, many desirable traits including high degree of resistance to multiple stresses that are present in the species belonging to secondary and tertiary gene pools can also be introgressed by using special techniques to overcome pre- and post-fertilization barriers. Besides resistance to various biotic and abiotic stresses, the yield QTLs have also been introgressed from wild Cicer species to cultivated varieties. Status and importance of molecular markers, genome mapping and genomic tools for chickpea improvement are elaborated. Because of major genes for various biotic and abiotic stresses, the transfer of agronomically important traits into elite cultivars has been made easy and practical through marker-assisted selection and marker-assisted backcross. The usefulness of molecular markers such as SSR and SNP for the construction of high-density genetic maps of chickpea and for the identification of genes/QTLs for stress resistance, quality and yield contributing traits has also been discussed

Glycoprotein gp130 of \u3ci\u3eDictyostelium discoideum\u3c/i\u3e Influences Macropinocytosis and Adhesion

Glycoprotein gp130, found on the plasma membrane of Dictyostelium discoideum amoebae, was postulated previously to play a role in phagocytosis. The gene for gp130 was cloned and when translated, yielded a 768 amino acid preproprotein of 85.3 kDa. It had nearly 40% similarity to the 138 kDa family of glycoproteins implicated in sexual cell fusion during macrocyst formation in D. discoideum. The difference between the calculated size and observed Mr of 130 kDa on protein gels likely was due to N-glycosylation that was confirmed by lectin blots. Consistent with its surface-exposure, an antibody raised against recombinant protein stained the plasma membrane of D. discoideum amoebae. Gp130 and its transcripts were high during axenic growth of cells, but relatively low during growth on bacteria. The gene for gp130 was disrupted and cell lines lacking the glycoprotein were efficient phagocytes, indicating that gp130 was dispensable for phagocytosis. Gp130-null cells were similar in size to parent DH1 cells, had enhanced macropinocytosis and grew faster to higher densities. They also exhibited weaker cell-substrate adhesion but displayed greater cell-cell cohesion. Collectively, the data indicated that gp130 influenced macropinocytosis and played a role in adhesion during vegetative growth

Rejuvenating irrigation tanks through local institutions

Recent attempts to modernise irrigation tanks with a focus on physical rehabilitation, but little institutional development to maintain and manage them, have resulted in a vicious cycle. With the lack of maintenance and upkeep, rehabilitated tanks soon fall into disrepair, necessitating a new round of externally-induced rehabilitation. Yet, there are many tanks under traditional local management operating at a high level of performance equilibrium. A study of 41 tanks from 22 districts of eight Indian states was taken up under the IWMI-Tata Programme to identify the characteristics of high performing local- managed tank institutions. The lessons learnt from the study can form the basis for an effective institutional protocol that can enhance the effectiveness of tank rehabilitation and modernization

Glycoprotein gp130 of Dictyostelium discoideum Influences Macropinocytosis and Adhesion

Glycoprotein gp130, found on the plasma membrane of Dictyostelium discoideum amoebae, was postulated previously to play a role in phagocytosis. The gene for gp130 was cloned and when translated, yielded a 768 amino acid preproprotein of 85.3 kDa. It had nearly 40% similarity to the 138 kDa family of glycoproteins implicated in sexual cell fusion during macrocyst formation in D. discoideum. The difference between the calculated size and observed M(r) of 130 kDa on protein gels likely was due to N-glycosylation that was confirmed by lectin blots. Consistent with its surface-exposure, an antibody raised against recombinant protein stained the plasma membrane of D. discoideum amoebae. Gp130 and its transcripts were high during axenic growth of cells, but relatively low during growth on bacteria. The gene for gp130 was disrupted and cell lines lacking the glycoprotein were efficient phagocytes, indicating that gp130 was dispensable for phagocytosis. Gp130-null cells were similar in size to parent DH1 cells, had enhanced macropinocytosis and grew faster to higher densities. They also exhibited weaker cell-substrate adhesion but displayed greater cell-cell cohesion. Collectively, the data indicated that gp130 influenced macropinocytosis and played a role in adhesion during vegetative growth

A study on the tolerance level of farmers toward human-wildlife conflict in the forest buffer zones of Tamil Nadu

Aim: The aim of this work was to study the tolerance level of farmers toward different human-wildlife conflict (HWC) situations. Materials and Methods: This study was conducted in 24 villages of nine blocks from Kancheepuram, Coimbatore, Erode, and Krishnagiri districts of Tamil Nadu by personally interviewing 240 farmers affected with four different HWC situations such as human-elephant conflict (HEC), human-wild pig conflict (HPC), human-gaur conflict (HGC), and human-monkey conflict (HMC). A scale developed for this purpose was used to find out the tolerance level of the farmers. Results: In general, the majority (61.70%) of the farmers had medium level of tolerance toward HWC, whereas 25.40% and 12.90% belonged to a high and low category, respectively. The mean tolerance level of the farmer’s encountering HMC is low (8.77) among the other three wild animal conflicts. In tackling HWC, the majority (55.00%) of the HEC farmers drove the elephant once it entered into their farmland. In the HPC, more than three-fourths of the respondents drove away the wild pig once they were found in farmlands. With regard to the HMC, a less number of them (1.70%) drove the monkey away if monkeys were spotted in their village. With regard to HGC, 95.00% of the respondents frightened the gaurs if their family members were threatened by gaurs. Conclusion: The present study suggests that that majority of the farmers had medium level of tolerance toward HWC. The tolerance level of the HMC farmers was lower than other three HWC affected farmers. This study emphasizes the need for necessary training to tackle the problem in an effective manner for wild animal conservation

Polygon Breeding: Old Hat or New Trick?

The author traces the development of "Polygon Breeding", which originated in E. Africa under the name "Diversified Bulk Population Breeding" in the cultivation of Phaseolus vulgaris, describing it as a multilocational breeding method with complete and continued sharing of populations and selections. Diagrams illustrate its application in triangle, tetragon and pentagon modes. A description is provided of a tetragon programme conducted for 4 chickpea cross populations in 1985-90, which showed that selection in one of 4 chosen environments was consistently more effective than in the other environments. The author concludes that the method is advantageous in (1) offering less restriction than breeding in one location, (2) enhancing national and international collaboration, (3) leaving options for wide-to-narrow adaptation, and (4) possibly helping avoid rivalry among breeding programmes

Biocontrol Properties and Functional Characterization of Rice Rhizobacterium Pseudomonas sp. VSMKU4036

A total of 30 fluorescent pseudomonads (FPs) were showed significant antagonistic activity against different fungal phytopathogens with different level of the zone of inhibition (ZOI) for Rhizoctonia solani (5mm-34mm), Macrophomina phaseolina (9mm-37mm), Scleotium rolfsii (4mm-36mm), Helminthusporium solani (5mm-27mm), Fusarium oxysporum (2mm-25mm) and Fusarium oxysporum RACE (4mm-31mm) compared to control. The maximum growth of our selected isolate VSMKU4036 was observed in King’B Broth (KBB), pH 7.0 and at 37°C. The VSMKU4036 isolate has been recognized as Pseudomonas sp, based on the morphological, biological, and different functional characteristics. Antagonistic rhizobacterium Pseudomonas sp VSMKU4036 produced antimicrobial traits, such as plant growth promotion and various functional characters like siderophores, hydrogen cyanide (HCN), phosphate solubilization, indole acetic acid (IAA), biofilms formation, protease, gelatinase, amylase, and pectinase. Our superior biocontrol isolate VSMKU4036 was high resistance to tetracycline, streptomycin and nalidixic acid, however, it was sensitive to ampicillin and rifamycin. Pseudomonas sp VSMKU4036 showed maximum resistance to cadmium, nickel chloride, copper sulphate, magnesium sulphate, zinc chloride and ferric chloride where as highly sensitive to mercuric chloride, and selenium dioxide compared to control