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This research forms a part of the comprehensive Indian Environmental Radiation Monitoring Network program, focusing on the continuous measurement of absorbed dose rate in outdoor air due to natural gamma radiation (cosmic and terrestrial) in Bengaluru, Karnataka, India. Over the course of a decade (2013-2023), data were collected from 41 monitoring locations in the city using permanently field-installed Geiger-Mueller detector-based environmental radiation monitors. This paper presents an analysis of the extensive long-term monitoring results. The mean absorbed gamma dose rate in outdoor air across the monitoring locations ranged from 84 ± 9 to 156 ± 4 nGy.h-1, with a calculated mean value of 124 ± 15 nGy.h-1. The estimated mean annual effective dose due to outdoor natural gamma radiation varied from 0.10 ± 0.01 to 0.19 ± 0.01 mSv.y-1, with an overall mean of 0.15 ± 0.02 mSv.y-1., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

This paper reports the results of gamma irradiation experiments and whole genome sequencing (WGS) performed on vegetative cells of two radiation resistant bacterial strains, Metabacillus halosaccharovorans (VITHBRA001) and Bacillus paralicheniformis (VITHBRA024) (D10 values 2.32 kGy and 1.42 kGy, respectively), inhabiting the top-ranking high background radiation area (HBRA) of Chavara-Neendakara placer deposit (Kerala, India). The present investigation has been carried out in the context that information on strategies of bacteria having mid-range resistance for gamma radiation is inadequate. WGS, annotation, COG and KEGG analyses and manual curation of genes helped us address the possible pathways involved in the major domains of radiation resistance, involving recombination repair, base excision repair, nucleotide excision repair and mismatch repair, and the antioxidant genes, which the candidate could activate to survive under ionizing radiation. Additionally, with the help of these data, we could compare the candidate strains with that of the extremely radiation resistant model bacterium Deinococccus radiodurans, so as to find the commonalities existing in their strategies of resistance on the one hand, and also the rationale behind the difference in D10, on the other. Genomic analysis of VITHBRA001 and VITHBRA024 has further helped us ascertain the difference in capability of radiation resistance between the two strains. Significantly, the genes such as uvsE (NER), frnE (protein protection), ppk1 and ppx (non-enzymatic metabolite production) and those for carotenoid biosynthesis, are endogenous to VITHBRA001, but absent in VITHBRA024, which could explain the former's better radiation resistance. Further, this is the first-time study performed on any bacterial population inhabiting an HBRA. This study also brings forward the two species whose radiation resistance has not been reported thus far, and add to the knowledge on radiation resistant capabilities of the phylum Firmicutes which are abundantly observed in extreme environment., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Pal et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Proso millet is a potential crop for food, nutritional security, and sustainable agriculture, particularly in the context of climate change. It is one of the traditional millet crops in cultivation in Tamil Nadu and India. Self-pollinated nature of this crop makes evolutionary process a terminal one and creating variability to broaden the genetic base is important. The objective of the study was to optimize mutagenic dose of gamma mutagen, document types of mutations and identify mutants for high grain yield (GY) and fodder yield (FY), hence to determine the feasibility of gamma mutagenesis in proso millet crop improvement. A mutation breeding program with 10 doses of gamma irradiation, i.e. 100, 200, 300, 400, 500, 600, 700, 800, 900 and 1000 Gy were imposed on seeds of variety ATL 1, a popular variety in India. Roll paper method, tray method and field evaluation were carried out to determine the LD50 and GR50 doses. Based on viable mutation frequency in M2 generation, mutagenic effectiveness and efficiency was estimated. Targeted selection for yield and yield contributing traits was carried out in M2, M3 and M4 generation to identify high yielding mutants. The LD50 and GR50 doses of gamma were estimated to be 418 Gy and 542 Gy, respectively. Based on results from probit analysis, mutagenic effectiveness, mutagenic efficiency and mutation spectrum, the optimum treatment dose of gamma was concluded to be 400 Gy. High frequency, i.e. 10.96% of phenotypic mutants was identified in the M2 generation. The broad range of mutants identified in M2 generation had mutations for plant height, plant habit, panicle shape, compactness, and length, days to 50% flowering (DFF), lodging resistance, tillering, leaf phenotype, apiculus color, culm branching, stem and leaf hairiness, sheath pigmentation, seed color and shape and seed coat attachment. Eight high yielding mutant families were isolated in M4 generation. The mean single plant GY and FY of these mutants ranged between 25 to 51 g and 40 to 68 g respectively while in control it was 15 g and 30 g, respectively. The wide spectrum and high frequency of mutations both for qualitative and quantitative traits suggest mutation induction as a promising method for creating novel variations in proso millet. The high yielding mutants identified can be utilized for varietal development both for grain and fodder purpose after further stability and quality evaluations in the advanced generations. [ABSTRACT FROM AUTHOR]

The Indian Environmental Radiation Monitoring Network continuously monitors, throughout India, the absorbed dose rate in air due to outdoor natural gamma radiation, by using Geiger–Mueller detector-based standalone environmental radiation monitors. The network consists of 546 monitors spread across 91 monitoring locations distributed all over the country. In this paper, the countrywide long-term monitoring results are summarised. The measured mean dose rate of the monitoring locations followed a log-normal distribution and ranged from 50 to 535 nGy.h−1 with a median value of 91 nGy.h−1. Due to outdoor natural gamma radiation, the average annual effective dose was estimated to be 0.11 mSv.y−1. [ABSTRACT FROM AUTHOR]

The Indian Environmental Radiation Monitoring Network continuously monitors the outdoor natural gamma absorbed dose rate in air at different locations throughout India by employing Geiger–Mueller (GM) detector-based field-installed environmental radiation monitors (ERMs). Hyderabad, Telangana, India is known to have high natural background radiation levels due to the presence of high concentrations of primordial radionuclides in its granitic rocks. There are a total of 59 ERMs installed at various locations across Hyderabad. Long-term monitoring data of these locations are presented in this paper. The mean values of outdoor natural gamma absorbed dose rate in air at the monitoring locations were found to vary in the range of 104–258 nGy.h−1 with a mean of 193 ± 40 nGy.h−1. The mean annual effective dose due to outdoor natural gamma radiation was estimated to be 0.24 ± 0.05 mSv.y−1. Analysis of the long-term seasonal variation of outdoor natural gamma absorbed dose rate in air showed that the same was lowest during monsoons. [ABSTRACT FROM AUTHOR]

Rapidly rotating neutron stars with very strong surface magnetic fields are observed to emit pulsed emission in the whole range of electromagnetic spectrum from radio to high-energy gamma rays. These so-called pulsars are known for their exceptional rotational stability. The radio emission from pulsars is generally believed to be powered by the rotational energy of neutron stars. More than 3000 pulsars have been currently known from radio observations; however, only about 10% are observed in the high-energy gamma ray band. The Fermi-LAT observations in the energy range above 100 MeV have discovered more than 300 pulsars. However, the origin of high-energy non-thermal radiation from pulsars is not completely understood and remains an active area of research. In this contribution, we report a summary of observational features of the gamma ray pulsars and briefly discuss observability for the MACE gamma ray telescope, which has just started its regular science operation at Hanle in India. Six gamma ray pulsars, other than the well-known Crab and Geminga, are identified as probable candidates for MACE observations. [ABSTRACT FROM AUTHOR]

This study reports the exhalation rates of radon and thoron from surface soil collected from 60 rural sites of district Hisar, Haryana, India. The exhalation rates of Rn222 (radon) and Rn220 (thoron) were measured by portable SMART RnDuo (AQTEK SYSTEMS) using a mass accumulation chamber which was equipped with a scintillation material–coated cell. Dose rates due to natural gamma radiations ranged from 0.526 to 1.139 mSv y−1. The Rn222 mass exhalation rate in soil samples varied from 0.14 to 94.65 mBq kg−1 h−1. Thoron surface exhalation rates ranged from 46.42 to 619.88 Bq m−2 h−1. This study gives an idea about the differences in Rn222 and Rn220 exhalation at different locations which may be due to variations in geological features of the locations and characteristics of the topsoil. The findings show that usage of study area soil as building material is safe. [ABSTRACT FROM AUTHOR]

Availability of dwarfing rootstocks is an important pre-requisite for improving productivity of mango orchards in India as it facilitates high density planting as well as impart uniformity within an orchard. An attempt was made to induce variability in polyembryonic mango genotype Nekkare for dwarfness by treating kernels with different doses of gamma radiation ranging from 15 to 35 Gy. Irradiation created significant variation in plant height, stem girth, number of nodes, inter-nodal length, number of leaves, leaf blade length and leaf blade width. The highest reduction in seedling height along with highest variation was observed at 35 Gy where the seedling height ranged from 11.50 to 33 cm with a mean of 23.12 cm as compared to mean plant height of 44.55 cm in control ranging from 33.50 to 56 cm. Further, the effect of irradiation on stomatal parameters was also investigated and the highest stomatal length and width was recorded at 15 Gy (63.39 µm) and 20 Gy (63.12 µm) respectively while 30 Gy treatment produced maximum stomatal density (13.85 per µm2). Furthermore, the concentration of ABA was found to be highest (429.1 ng/gm) in morphologically dwarf (putative mutant) progenies of Nekkare. The results suggest effectiveness of induced mutation for developing dwarfing rootstocks in mango to be used in high density planting. [ABSTRACT FROM AUTHOR]