Ranjan Tamuli

Piper betle-mediated green synthesis of biocompatible gold nanoparticles

Here, we report the novel use of the ethonolic leaf extract of Piper betle for gold nanoparticle (AuNP) synthesis. The successful formation of AuNPs was confirmed by UV-visible spectroscopy, and different parameters such as leaf extract concentration (2%), gold salt concentration (0.5 mM), and time (18 s) were optimized. The synthesized AuNPs were characterized with different biophysical techniques such as transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). TEM experiments showed that nanoparticles were of various shapes and sizes ranging from 10 to 35 nm. FT-IR spectroscopy revealed that AuNPs were functionalized with biomolecules that have primary amine group –NH2, carbonyl group, –OH groups, and other stabilizing functional groups. EDX showed the presence of the elements on the surface of the AuNPs. FT-IR and EDX together confirmed the presence of biomolecules bounded on the AuNPs. Cytotoxicity of the AuNPs was tested on HeLa and MCF-7 cancer cell lines, and they were found to be nontoxic, indicating their biocompatibility. Thus, synthesized AuNPs have potential for use in various biomedical applications.

Neurospora crassa homologue of Neuronal Calcium Sensor-1 has a role in growth, calcium stress tolerance, and ultraviolet survival

NCU04379 gene encodes a conserved Ca2+ and/or calmodulin binding protein that possesses a consensus signal for N-terminal myristoylation and four EF-hands, characteristics of Neuronal Calcium Sensor-1proteins. The NCU04379.2 knockout mutant shows slow growth rate, increased sensitivity to calcium and ultraviolet (UV) irradiation, and a wild-type fragment carrying NCU04379 gene complements the mutant. Therefore, NCU04379 gene has a role in growth, calcium stress tolerance, and UV survival. Crosses homozygous for ΔNCU04379.2 mutant strains were fully fertile; however, we found evidence for involvement of Ca2+/calmodulin-dependent protein kinase encoding genes NCU02283 and NCU09123 in sexual development.

Calcium/calmodulin-dependent kinases are involved in growth, thermotolerance, oxidative stress survival, and fertility in Neurospora crassa.

Calcium/calmodulin-dependent kinases (Ca2+/CaMKs) are Ser/Thr protein kinases that respond to change in cytosolic free Ca2+ ([Ca2+]c) and play multiple cellular roles in organisms ranging from fungi to humans. In the filamentous fungus Neurospora crassa, four Ca2+/CaM-dependent kinases, Ca2+/CaMK-1 to 4, are encoded by the genes NCU09123, NCU02283, NCU06177, and NCU09212, respectively. We found that camk-1 and camk-2 are essential for full fertility in N. crassa. The survival of ∆camk-2 mutant was increased in induced thermotolerance and oxidative stress conditions. In addition, the ∆camk-1∆camk-2, ∆camk-4∆camk-2, and ∆camk-3∆camk-2 double mutants display slow growth phenotype, reduced aerial hyphae, decreased thermotolerance, and increased sensitivity to oxidative stress, revealing the genetic interactions among these kinases. Therefore, Ca2+/CaMKs are involved in growth, thermotolerance, oxidative stress tolerance, and fertility in N. crassa.

Cellular roles of neuronal calcium sensor‐1 and calcium/calmodulin‐dependent kinases in fungi

The neuronal calcium sensor‐1 (NCS‐1) possesses a consensus signal for N‐terminal myristoylation and four EF‐hand Ca2+‐binding sites, and mediates the effects of cytosolic Ca2+. Minute changes in free intracellular Ca2+ are quickly transformed into changes in the activity of several kinases including calcium/calmodulin‐dependent protein kinases (Ca2+/CaMKs) that are involved in regulating many eukaryotic cell functions. However, our current knowledge of NCS‐1 and Ca2+/CaMKs comes mostly from studies of the mammalian enzymes. Thus far very few fungal homologues of NCS‐1 and Ca2+/CaMKs have been characterized and little is known about their cellular roles. In this minireview, we describe the known sequences, interactions with target proteins and cellular roles of NCS‐1 and Ca2+/CaMKs in fungi. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Multiple cellular roles of Neurospora crassa plc-1 , splA2 , and cpe-1 in regulation of cytosolic free calcium, carotenoid accumulation, stress responses, and acquisition of thermotolerance

Phospholipase C1 (PLC1), secretory phospholipase A2 (sPLA2) and Ca2+/H+ exchanger proteins regulate calcium signaling and homeostasis in eukaryotes. In this study, we investigate functions for phospholipase C1 (plc-1), sPLA2 (splA2) and a Ca2+/H+ exchanger (cpe-1) in the filamentous fungus Neurospora crassa. The Δplc-1, ΔsplA2, and Δcpe-1 mutants exhibited a growth defect on medium supplemented with the divalent ionophore A23187, suggesting that these genes might play a role in regulation of cytosolic free Ca2+ concentration ([Ca2+]c) in N. crassa. The strains lacking plc-1, splA2, and cpe-1 possessed higher carotenoid content than wild type at 8°C, 22°C, and 30°C, and showed increased ultraviolet (UV)-survival under conditions that induced carotenoid accumulation. Moreover, Δplc-1, ΔsplA2, and Δcpe-1 mutants showed reduced survival rate under hydrogen peroxide-induced oxidative stress and induced thermotolerance after exposure to heat shock temperatures. Thus, this study revealed multiple cellular roles for plc-1, splA2, and cpe-1 genes in regulation of [Ca2+]c, carotenoid accumulation, survival under stress conditions, and acquisition of thermotolerance induced by heat shock.

Neurospora crassa ncs-1, mid-1 and nca-2 double-mutant phenotypes suggest diverse interaction among three Ca 2+ -regulating gene products

The calcium (Ca2+) signalling system in the filamentous fungus Neurospora crassa is unique and significantly different from that in plants and animals, mainly with regard to the second messenger systems involved in Ca2+-release from internal stores (Galagan et al. 2003). The complex Ca2+ signalling system in N. crassa contains 48 Ca2+ signalling proteins including a Ca2+ and/or CaM binding protein called neuronal calcium sensor-1 (NCS-1), a Ca2+-permeable channel MID-1 and a PMCA-type Ca2+-ATPase NCA-2 (Zelter et al. 2004; Tamuli et al. 2013). Here, we show that ncs-1, mid-1 and nca-2 interactions affect growth, carotenoid accumulation, Ca2+ stress tolerance, ultraviolet (UV) survival and circadian-regulated conidiation in N. crassa. The N. crassa homologue of NCS-1 has a role in growth, Ca2+ stress tolerance and UV survival (Deka et al. 2011; Tamuli et al. 2011). MID-1 is necessary for Ca2+homeostasis in N. crassa (Lew et al. 2008). Mid-1 in Gibberella zeae has a role in growth, development and ascospore discharge (Cavinder et al. 2011). NCA-2 is responsible for adaptation to stress conditions and functions to pump Ca2+ out of the cell in N. crassa (Benito et al. 2000; Bowman et al. 2011). In Schizosaccharomyces pombe, Ncs1p, the homologue of NCS-1, promotes Ca2+-induced closure of Yam8p Ca2+ channel, a homologue of the MID1 (Hamasaki-Katagiri and Ames 2010). The Ca2+-sensitive phenotype of the ncs1 deletion mutant is rescued by a yam8 deletion, indicating that Ncs1p negatively regulates Yam8p in S. pombe

Gold nanoparticles: sonocatalytic synthesis using ethanolic extract of Andrographis paniculata and functionalization with polycaprolactone-gelatin composites

Gold nanoparticles (AuNPs) were synthesized by sonication using ethanolic leaf extract of Andrographis paniculata. We investigated the optimum parameters for AuNP synthesis and functionalization with polycaprolactone-gelatin (PCL-GL) composites. The AuNPs were characterized with various biophysical techniques such as TEM, XRD, FT-IR and EDX spectroscopy. TEM images showed that nanoparticles were spherical in shape with a size range from 5 to 75 nm. EDX analysis revealed the presence of molecular oxygen and carbon on the surface of AuNPs. The synthesized AuNPs were tested for their effect on HeLa (human cervical cancer) and MCF-7 (human breast cancer) cell lines and found to be nontoxic and biocompatible, which are potential carriers for hydrophobic drugs.

Green Synthesis and Characterization of Biocompatible Gold Nanoparticles Using Solanum indicum Fruits

This paper reports on the eco-friendly synthesis of gold nanoparticles (AuNPs) using Solanum indicum fruit extract (SFE). We have evaluated various parameters for synthesis of AuNPs such as SFE (0.03%), HAuCl4 (0.5 mM) and reaction time (20 seconds). The synthesized AuNPs were characterized with different physical techniques such as transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). TEM experiments showed that AuNPs presented an anisotropic shape and size ranging from 5-50nm. FT-IR spectroscopy revealed that biomolecules containing an amine group (-NH2), a carbonyl group, -OH groups and other stabilizing functional groups were adsorbed on the surface of the synthesized AuNPs. EDX showed the presence of the elements on the surface of the AuNPs. The cytotoxicity of the synthesized AuNPs were tested on two different human cancer cell lines, HeLa and MCF-7 and were found to be nontoxic, thus providing an opportunity to be used in biomedical applications.

NRF1 (nuclear respiratory factor 1)

Review on NRF1 (nuclear respiratory factor 1), with data on DNA, on the protein encoded, and where the gene is implicated.

The pleiotropic vegetative and sexual development phenotypes of Neurospora crassa arise from double mutants of the calcium signaling genes plc-1, splA2, and cpe-1

We investigated phenotypes of the double mutants of the calcium (Ca2+) signaling genes plc-1, splA2, and cpe-1 encoding for a phospholipase C1 (PLC-1), a secretory phospholipase A2 (sPLA2), and a Ca2+/H+ exchanger (CPE-1), respectively, to understand the cell functions regulated by their genetic interactions. Mutants lacking plc-1 and either splA2 or cpe-1 exhibited numerous defects including reduced colonial growth, stunted aerial hyphae, premature conidiation on plates with delayed germination, inappropriate conidiation in submerged culture, and lesser mycelial pigmentation. Moreover, the ∆plc-1; ∆splA2 and ∆plc-1; ∆cpe-1 double mutants were female-sterile when crossed with wild type as the male parent. In addition, ∆plc-1, ∆splA2, and ∆cpe-1 single mutants displayed higher carotenoid accumulation and an increased level of intracellular reactive oxygen species (ROS). Therefore, the pleiotropic phenotype of the double mutants of plc-1, splA2, and cpe-1 suggested that the genetic interaction of these genes plays a critical role for normal vegetative and sexual development in N. crassa.