A Novel Alpha Kinase EhAK1 Phosphorylates Actin and Regulates Phagocytosis in Entamoeba histolytica

Phagocytosis plays a key role in nutrient uptake and virulence of the protist parasite Entamoeba histolytica. Phagosomes have been characterized by proteomics, and their maturation in the cells has been studied. However, there is so far not much understanding about initiation of phagocytosis and formation of phagosomes at the molecular level. Our group has been studying initiation of phagocytosis and formation of phagosomes in E. histolytica, and have described some of the molecules that play key roles in the process. Here we show the involvement of EhAK1, an alpha kinase and a SH3 domain containing protein in the pathway that leads to formation of phagosomes using red blood cell as ligand particle. A number of approaches, such as proteomics, biochemical, confocal imaging using specific antibodies or GFP tagged molecules, expression down regulation by antisense RNA, over expression of wild type and mutant proteins, were used to understand the role of EhAK1 in phagocytosis. EhAK1 was found in the phagocytic cups during the progression of cups, until closure of phagosomes, but not in the phagosomes themselves. It is recruited to the phagosomes through interaction with the calcium binding protein EhCaBP1. A reduction in phagocytosis was observed when EhAK1 was down regulated by antisense RNA, or by over expression of the kinase dead mutant. G-actin was identified as one of the major substrates of EhAK1. Phosphorylated actin preferentially accumulated at the phagocytic cups and over expression of a phosphorylation defective actin led to defects in phagocytosis. In conclusion, we describe an important component of the pathway that is initiated on attachment of red blood cells to E. histolytica cells. The main function of EhAK1 is to couple signalling events initiated after accumulation of EhC2PK to actin dynamics.     

Statistical optimization of medium components to increase the manganese peroxidase productivity by Phanerochaete chrysosporium NCIM 1197

The production of manganese peroxidase (MnP) by the white-rot fungus Phanerochaete chrysosporium NCIM 1197 was investigated by the screening and optimization of the media constituents and physiological factors. MnP production by the fungus was used as the response to screen the media constituents with statistically valid Plackett-Burman (P-B) design. Response surface methodology (RSM) was applied to optimize the level of screened media constituents. Amongst the media constituents screened, glucose, maltose, ammonium chloride, and urea were selected as the most important for MnP enhancement. A five-level Central Composite Design (CCD) was used in optimizing the important media constituents for maximizing the MnP production. The optimal medium composition for maximum MnP production was 13.88 mM of glucose, 13.88 mM of maltose, 0.02 mM of ammonium chloride, and 0.02 mM of urea. The final experiment was conducted to validate the model, which was shown to produce 70.20 U/mL of MnP with a predicted value of 66.49 U/mL on the 8^th day of incubation.     

Correction to: The biotechnological importance of the plant-specific NAC transcription factor family in crop improvement

Climate change, malnutrition, and food insecurity are the inevitable challenges being faced by the agriculture sector today. Plants are susceptible to extreme temperatures during the crucial phases of flowering and seed development, and elevated carbon levels also lead to yield losses. Productivity is also affected by floods and droughts. Therefore, increasing plant yield and stress tolerance are the priorities to be met through novel biotechnological interventions. The contributions of NAC genes towards enhancing plant survivability under stress is well known. Here we focus on the potential of NAC genes in the regulation of abiotic stress tolerance, secondary cell wall synthesis, lateral root development, yield potential, seed size and biomass, ROS signaling, leaf senescence, and programmed cell death. Once naturally tolerant candidate NAC genes have been identified, and the nature of their association with growth and fitness against multi-environmental stresses has been determined, they can be exploited for building inherent tolerance in future crops via transgenic technologies. An update on the latest developments is provided in this review, which summarizes the current understanding of the roles of NAC in the establishment of various stress-adaptive mechanisms in model and food crop plants.

     

Allantoin mediated regulation of miRNAs for short term salinity stress tolerance in Oryza sativa L. cv. IR-29

Journal of Plant Biochemistry and Biotechnology - Salinity affects plant in a variety of ways, including ion toxicity, osmotic stress and oxidative damage. Allantoin is a nitrogenous compound...     

Cancer and non-cancer health risk assessment associated with exposure to non-methane hydrocarbons among roadside vendors in Delhi,India

Abstract

This study estimates the cancer and non-cancer health risk among the roadside vendors in Delhi, the capital city of India. Air samples of selected NMHCs and their derivatives were collected from four different sites (one traffic intersection, one industrial, and two residential) in Delhi and were analyzed on Gas Chromatograph (GC) to obtain their atmospheric concentrations. At each site, a survey among the roadside vendors was also conducted to obtain information about their bodyweight and exposure to outdoor ambient air. The study reveals that hazard quotient of 1,3-butadiene is greater than one at all the sites, with its maximum value occurring at the industrial site. The major contributors to the workplace cancer risk (WCR) are found to be 1,3-butadiene and chloroform. The overall WCR is observed to be the highest (9.4?×?10^?4) at the traffic intersection site, followed by the industrial site (7.0?×?10^?4). Cancer incidence data and the population data are also used to estimate the growth of cancer risk in Delhi from 2009 to 2016. Comparison of the WCR values of the four sites with the cancer risk estimated from the cancer incidence data shows that NMHCs and their derivatives are significant contributors to the overall cancer risk in Delhi. Our results suggest that NMHCs and their derivatives need to be given due consideration in the National Cancer Control Programme of India.     

Iron status,malaria parasite loads and food policies: Evidence from sub-Saharan Africa

This brief article investigates the consequences of improving children's iron status for malaria parasite loads by analyzing data from Cote d’Ivoire, Zambia, and Tanzania; the treatment of iron deficiencies has been argued to flare up malaria in under-nourished populations. The data from a randomized controlled trial in Cote d’Ivoire showed statistically insignificant effects of the consumption of iron-fortified biscuits on children's malaria parasite loads. Second, nutrient intakes data from Zambia showed insignificant correlations and associations between children's iron and folate intakes and malaria parasite loads. Third, malaria parasite loads did not change significantly for Tanzanian children receiving anthelmintic treatment; malaria loads were lower for older children and for those using bed nets. Overall, the evidence from sub-Saharan African countries suggests that small improvements in iron status achieved via suitable food policies are unlikely to have detrimental effects for children's malaria parasite loads.     

Retention of enzyme activity following freeze-drying the mycelium of ectomycorrhizal isolates

Qualitative enzyme assays were used as a tool to investigate the stability of freeze-dried mycorrhizal fungi. Both lyophilized (L) and non-lyophilized (NL) mycelia of individual isolates showed identical response for all the enzymes tested (nitrate reductase, protease, pectinase, and nuclease). All the isolates showed positive nitrate reductase activity, except two isolates of Thelephora terrestris (both L and NL). Both L and NL cultures of individual isolates showed substrate specificity (between gelatin and casein) for protease activity. Though both L and NL mycelia of all the culture isolates grew upon pectin substrate, there was no pectinase activity expressed. RNAase activity was variously exhibited (little activity, little growth–no activity, and no growth–no activity) by individual test cultures. The consistencies in growth and enzyme activity of the cultures before and after lyophilization imply the stability of the freeze-dried vegetative mycelium.