Odor reception in antenna and antennal lobe of Drosophila

In early years of neurogenetics of Drosophila, most of us were inclined to believe that behavior of the fruit fly is largely stereotyped and hard-wired. This, at least, was a common prejudice when genetic analysis of olfaction began. We now know that Drosophila like other insects is capable of several types of learning or experience-dependent modification of behavior.     

Diseases and their clinical heterogeneity – Are we ignoring the SNiPers and micRomaNAgers? An illustration using Beta-thalassemia clinical spectrum and fetal hemoglobin levels

Diseases and pathological ailments are known to perplex clinicians and researchers with their varied clinical manifestations. Such variations are mostly attributed to the complex interplays between numerous molecular players and their modifiers. This complexity in turn baffles scientists further to tweak multiple players together when attempting to identify definitive therapeutic interventions. In this pursuit, researchers often tend to ignore one of the commonest known genetic variations – single nucleotide polymorphisms (SNPs) in non-coding genetic regions. In this study, we demonstrate how SNPs in critical genes and their miRNA regulators may play a crucial role in varied clinical manifestations using the beta-thalassemia clinical spectrum and fetal hemoglobin levels (HbF) as an illustration. A methodological approach using freely available bioinformatics tools was able to identify SNPs in pre-miRNA regions, pre-miRNA flanking regions and miRNA binding sites which in turn are expected to alter the translation process and thereby the expression of HbF.     

Plasmid-encoded NP73-102 modulates atrial natriuretic peptide receptor signaling and plays a critical role in inducing tolerogenic dendritic cells

Background

Atrial natriuretic peptide (ANP) is an important endogenous hormone that controls inflammation and immunity by acting on dendritic cells (DCs); however, the mechanism remains unclear.

Objective

We analyzed the downstream signaling events resulting from the binding of ANP to its receptor, NPRA, and sought to determine what aspects of this signaling modulate DC function.

Methods

We utilized the inhibitory peptide, NP73-102, to block NPRA signaling in human monocyte-derived DCs (hmDCs) and examined the effect on DC maturation and induced immune responses. The potential downstream molecules and interactions among these molecules involved in NPRA signaling were identified by immunoprecipitation and immunoblotting. Changes in T cell phenotype and function were determined by flow cytometry and BrdU proliferation ELISA. To determine if adoptively transferred DCs could alter the in vivo immune response, bone marrow-derived DCs from wild-type C57BL/6 mice were incubated with ovalbumin (OVA) and injected i.v. into C57BL/6 NPRA-/- knockout mice sensitized and challenged with OVA. Lung sections were stained and examined for inflammation and cytokines were measured in bronchoalveolar lavage fluid collected from parallel groups of mice.

Results

Inhibition of NPRA signaling in DCs primes them to induce regulatory T cells. Adoptive transfer of wild type DCs into NPRA-/- mice reverses the attenuation of lung inflammation seen in the NPRA-knockout model. NPRA is associated with TLR-2, SOCS3 and STAT3, and inhibiting NPRA alters expression of IL-6, IL-10 and TGF-β, but not IL-12.

Conclusions

Modulation of NPRA signaling in DCs leads to immune tolerance and TLR2 and SOCS3 are involved in this induction.     

Improving nutritional quality and fungal tolerance in soya bean and grass pea by expressing an oxalate decarboxylase

Soya bean (Glycine max) and grass pea (Lathyrus sativus) seeds are important sources of dietary proteins; however, they also contain antinutritional metabolite oxalic acid (OA). Excess dietary intake of OA leads to nephrolithiasis due to the formation of calcium oxalate crystals in kidneys. Besides, OA is also a known precursor of β‐N‐oxalyl‐L ‐α,β‐diaminopropionic acid (β‐ODAP), a neurotoxin found in grass pea. Here, we report the reduction in OA level in soya bean (up to 73%) and grass pea (up to 75%) seeds by constitutive and/or seed‐specific expression of an oxalate‐degrading enzyme, oxalate decarboxylase (FvOXDC) of Flammulina velutipes. In addition, β‐ODAP level of grass pea seeds was also reduced up to 73%. Reduced OA content was interrelated with the associated increase in seeds micronutrients such as calcium, iron and zinc. Moreover, constitutive expression of FvOXDC led to improved tolerance to the fungal pathogen Sclerotinia sclerotiorum that requires OA during host colonization. Importantly, FvOXDC‐expressing soya bean and grass pea plants were similar to the wild type with respect to the morphology and photosynthetic rates, and seed protein pool remained unaltered as revealed by the comparative proteomic analysis. Taken together, these results demonstrated improved seed quality and tolerance to the fungal pathogen in two important legume crops, by the expression of an oxalate‐degrading enzyme.     

Apoptosis of metastatic prostate cancer cells by a combination of cyclin-dependent kinase and AKT inhibitors

Effective treatments for advanced prostate cancer are much needed. Toward this goal, we show apoptosis and impaired long-term survival of androgen-independent prostate cancer cells (PC3 and PC3 derivatives) co-treated with the cyclin-dependent kinase (CDK) inhibitor roscovitine and an AKT inhibitor (LY294002 or API-2). Apoptosis of PC3 cells by the drug combination required caspase-9 but not caspase-8 activity and thus is mitochondria-dependent. Roscovitine reduced amounts of the caspase inhibitor XIAP, and API-2 increased amounts of the BH3-only protein Bim. PC3 cells apoptosed when co-treated with API-2 and either cdk9 siRNA, dominant-negative cdk9, or the cdk9 inhibitor DRB; they did not apoptose when co-treated with API-2 and XIAP siRNA. Bax accumulated in mitochondria in response to API-2, whereas release of cytochrome c from mitochondria required both API-2 and roscovitine. We suggest that roscovitine elicits events that activate Bax once it translocates to mitochondria and that inactivation of cdk9 signals these events and the down-regulation of XIAP. Collectively, our data show apoptosis of prostate cancer cells by a drug combination and identify Bax activation as a basis of cooperation.     

Comparative proteomics of dehydration response in the rice nucleus: New insights into the molecular basis of genotype‐specific adaptation

Dehydration is the most crucial environmental factor that considerably reduces the crop harvest index, and thus has become a concern for global agriculture. To better understand the role of nuclear proteins in water‐deficit condition, a nuclear proteome was developed from a dehydration‐sensitive rice cultivar IR‐64 followed by its comparison with that of a dehydration‐tolerant c.v. Rasi. The 2DE protein profiling of c.v. IR‐64 coupled with MS/MS analysis led to the identification of 93 dehydration‐responsive proteins (DRPs). Among those identified proteins, 78 were predicted to be destined to the nucleus, accounting for more than 80% of the dataset. While the detected number of protein spots in c.v. IR‐64 was higher when compared with that of Rasi, the number of DRPs was found to be less. Fifty‐seven percent of the DRPs were found to be common to both sensitive and tolerant cultivars, indicating significant differences between the two nuclear proteomes. Further, we constructed a functional association network of the DRPs of c.v. IR‐64, which suggests that a significant number of the proteins are capable of interacting with each other. The combination of nuclear proteome and interactome analyses would elucidate stress‐responsive signaling and the molecular basis of dehydration tolerance in plants.     

A threefold RNA-protein interface in the signal recognition particle gates native complex assembly

Intermediate states play well-established roles in the folding and misfolding reactions of individual RNA and protein molecules. In contrast, the roles of transient structural intermediates in multi-component ribonucleoprotein (RNP) assembly processes and their potential for misassembly are largely unexplored. The SRP19 protein is unstructured but forms a compact core domain and two extended RNA-binding loops upon binding the signal recognition particle (SRP) RNA. The SRP54 protein subsequently binds to the fully assembled SRP19-RNA complex to form an intimate threefold interface with both SRP19 and the RNA and without significantly altering the structure of SRP19. We show, however, that the presence of SRP54 during SRP19-RNA assembly dramatically alters the folding energy landscape to create a non-native folding pathway that leads to an aberrant SRP19-RNA conformation. The misassembled complex arises from the surprising ability of SRP54 to bind rapidly to an SRP19-RNA assembly intermediate and to interfere with subsequent folding of one of the RNA binding loops at the three-way protein-RNA interface. An incorrect temporal order of assembly thus readily yields a non-native three-component ribonucleoprotein particle. We propose there may exist a general requirement to regulate the order of interaction in multi-component RNP assembly reactions by spatial or temporal compartmentalization of individual constituents in the cell.     

A Time Since Recovery Model with Varying Rates of Loss of Immunity

For many infectious diseases, immunity wanes over time. The majority of SIRS models assume that this loss of immunity takes place at a constant rate. We study temporary immunity within a SIRS model structure if the rate of loss of immunity can depend on the time since recovery from disease. We determine the conditions under which the endemic steady state becomes unstable and periodic oscillations set in, showing that a fairly rapid change between slow and rapid immunity loss is necessary to produce oscillations.     

Study of antimicrobial activity and root symbionts of Hemionitis arifolia

Antibacterial and antifungal activity of crude extract, alcoholic extract and extracted phenol from various parts of tropical pteridophyta, Hemionitis arifolia were tested by agar diffusion and tube dilution assay. Both the crude and alcoholic extracts of vegetative and reproductive leaves of H. arifolia showed considerable antibacterial activity against Gram negative test strain of Escherichia coli (MTCC-739). Extract from reproductive leaves also showed moderate antibacterial activity against Bacillus subtilis (MTCC-441) (Gram positive test strain) but didn’t show any antifungal activity against Candida albicans (MTCC-7353). Mycorrhizal and other symbiotic association with the root system of H. arifolia was studied and it is revealed that a number of mycorrhizal strains were present in both vegetative and reproductive form. Presence of Dark Septate Endophytic Fungi (DSF) was also detected.