Regulation of Plant Developmental Processes by a Novel Splicing Factor

Serine/arginine-rich (SR) proteins play important roles in constitutive and alternative splicing and other aspects of mRNA metabolism. We have previously isolated a unique plant SR protein (SR45) with atypical domain organization. However, the biological and molecular functions of this novel SR protein are not known. Here, we report biological and molecular functions of this protein. Using an in vitro splicing complementation assay, we showed that SR45 functions as an essential splicing factor. Furthermore, the alternative splicing pattern of transcripts of several other SR genes was altered in a mutant, sr45-1, suggesting that the observed phenotypic abnormalities in sr45-1 are likely due to altered levels of SR protein isoforms, which in turn modulate splicing of other pre-mRNAs. sr45-1 exhibited developmental abnormalities, including delayed flowering, narrow leaves and altered number of petals and stamens. The late flowering phenotype was observed under both long days and short days and was rescued by vernalization. FLC, a key flowering repressor, is up-regulated in sr45-1 demonstrating that SR45 influences the autonomous flowering pathway. Changes in the alternative splicing of SR genes and the phenotypic defects in the mutant were rescued by SR45 cDNA, further confirming that the observed defects in the mutant are due to the lack of SR45. These results indicate that SR45 is a novel plant-specific splicing factor that plays a crucial role in regulating developmental processes

Amyloid Plaques Beyond Aβ: A Survey of the Diverse Modulators of Amyloid Aggregation

Aggregation of the amyloid-β (Aβ) peptide is strongly correlated with Alzheimer’s disease (AD). Recent research has improved our understanding of the kinetics of amyloid fibril assembly and revealed new details regarding different stages in plaque formation. Presently, interest is turning toward studying this process in a holistic context, focusing on cellular components which interact with the Aβ peptide at various junctures during aggregation, from monomer to cross-β amyloid fibrils. However, even in isolation, a multitude of factors including protein purity, pH, salt content, and agitation affect Aβ fibril formation and deposition, often producing complicated and conflicting results. The failure of numerous inhibitors in clinical trials for AD suggests that a detailed examination of the complex interactions that occur during plaque formation, including binding of carbohydrates, lipids, nucleic acids, and metal ions, is important for understanding the diversity of manifestations of the disease. Unraveling how a variety of key macromolecular modulators interact with the Aβ peptide and change its aggregation properties may provide opportunities for developing therapies. Since no protein acts in isolation, the interplay of these diverse molecules may differentiate disease onset, progression, and severity, and thus are worth careful consideration

Comparison of Total Antioxidant Capacity of Serum in Type 2 Diabetic Patients and Healthy Individuals

Introduction: All the non-enzymatic materials in serum that have antioxidant properties are called antioxidant capacity. These materials protect the body against damage from free radicals. Therefore, this study aimed to compare the total antioxidant capacity of serum of diabetic patients with the healthy individuals as the control group. Methods: In this case-control study, 30 patients with type 2 diabetes referring to Zahedan Diabetes Center were assigned into the case group which were compared with 30 participants from control group, who were homogenous with the case croup in terms of age, gender and the other inclusion criteria. The antioxidant capacity of serum was evaluated with FRAP method. The study data were analyzed by T-test and Pearson’s correlation. Results: Serum total antioxidant capacity of patients compared with the control group showed a significant reduction (p<0.05). There was an inverse relationship between serum total antioxidant capacity and serum glucose concentrations in both diabetic patients and healthy subjects, though this relationship was not statistically significant in any of the two groups. No statistically significant relationship was found between total antioxidant capacity of serums and age. Conclusion: the study results revealed that the antioxidant immune system becomes weakened in type 2 diabetic patients. Considering the activity variations of the antioxidant enzymes in these patients can be helpful in reducing complications of diabetes