Jaya Prakash Shrivastava - Academia.edu (original) (raw)

Papers by Jaya Prakash Shrivastava

Research paper thumbnail of Evidence of biotic recovery through the Cretaceous/Palaeogene transition from the Mahadeo-Cherrapunji succession in the Meghalaya shelf, India

Palaeobiodiversity and Palaeoenvironments

Earlier studies on the Mahadeo-Cherrapunji road (MCR) section have documented the Cretaceous-Pala... more Earlier studies on the Mahadeo-Cherrapunji road (MCR) section have documented the Cretaceous-Palaeogene Boundary (KPB ca.6 6 Ma), but rare data exist on the Deccan volcanism induced KPB transition and related faunal crises. The environmental stress on biota has been postulated as the main cause of mass extinction. Thus, the study of organic matter (OM) entrapped in the Maastrichtian-Danian shelf sediments has attained importance, although the existing data is inadequate. In this situation, layer-wise n-alkanes and nfatty acids analyses were carried out using GC-MS. Obtained data show sudden increase in the short chain n-alkane (SCA~6-fold), nfatty acid (FA) and hopane (> sterane) concentrations. This suggests enhanced continental runoff and soil bacteria biomass passage into the marine realm. Comparing the MCR to the published KPB bearing shallow-marine facies of the Um-Sohryngkew River (USR) section data, we document high SCA and FA contents together with the abundance of the even carbon numbered SCA (n-C 16 and n-C 18). This suggests thermal degradation and partial combustion of non-woody biomass. The presence of C 17 n-alkane and hopane is indicative of their derivation from the algae, fungi and bacteria. A sudden SCA concentration increase coincides with the reported major foraminifers' extinction between the CF1 and P0 biozones of the MCR section. Further, a similar anomaly exists in the lower part of the CF3 biozone of the USR section and precedes extinction of the main foraminifers' assemblages. The excursions in SCA content along with hopane and FA are matching well with the major incidences of the Deccan volcanic episodes and convergence of the Indian-plate with the Eurasian plate occurred at 66 Ma (Beck et al. 1995) and with the Burmese-plate during Maastrichtian (Wakita and Metcalfe 2005). These events were responsible for the seawater disturbances, eustatic and depositional changes, including the retreat of the Tethys. Thus, a combination of extra-basinal and tectono-thermal events together with the greenhouse effects led to unexpected temperature rise and recurrent local sea-level changes that may have resulted in stress and faunal crisis.

Research paper thumbnail of Comparative Evaluation of Biodegradation Potential of Arthrobacter chlorophenolicus and Microbacterium esteraromaticum for Cyclic Nitramine Explosive Octahydro-1 , 3 , 5 , 7-Tetranitro-1 , 3 , 5 . 7-Tetrazocine ( HMX )

Best known for its explosive properties, HMX is also an environmental pollutant of concern contam... more Best known for its explosive properties, HMX is also an environmental pollutant of concern contaminating numerous military sites in India and world around. Many years of manufacture, processing and use of Octahydro1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX) in military installations worldwide have caused widespread contamination of water, soil and sediments. Pollution of the environment by munitions occurs primarily through the discharge of untreated process wastes and residues from explosives manufacturing and processing plants. HMX, a possible human carcinogen, is toxic to biological system, and is recalcitrant to degradation. Therefore, the removal of HMX from explosive contaminated environment is crucial for the safety of ecosystems and human health. Among the several existing remediation approaches, microbial biodegradation is the most economical and eco-friendly cleanup option. In this study, we evaluated biodegradation efficiency of two bacteria viz. Arthrobacter chlor...

Research paper thumbnail of Population Genetics of Schistosoma japonicum within the Philippines Suggest High Levels of Transmission between Humans and Dogs

PLoS Neglected Tropical Diseases, 2008

Background: Schistosoma japonicum, which remains a major public health problem in the Philippines... more Background: Schistosoma japonicum, which remains a major public health problem in the Philippines and mainland China, is the only schistosome species for which zoonotic transmission is considered important. While bovines are suspected as the main zoonotic reservoir in parts of China, the relative contributions of various non-human mammals to S. japonicum transmission in the Philippines remain to be determined. We examined the population genetics of S. japonicum in the Philippines in order to elucidate transmission patterns across host species and geographic areas. Methodology/Principal Findings: S. japonicum miracidia (hatched from eggs within fecal samples) from humans, dogs, pigs and rats, and cercariae shed from snail-intermediate hosts, were collected across two geographic areas of Samar Province. Individual isolates were then genotyped using seven multiplexed microsatellite loci. Wright's F ST values and phylogenetic trees calculated for parasite populations suggest a high frequency of parasite gene-flow across definitive host species, particularly between dogs and humans. Parasite genetic differentiation between areas was not evident at the definitive host level, possibly suggesting frequent import and export of infections between villages, although there was some evidence of geographic structuring at the snail-intermediate host level. Conclusions/Significance: These results suggest very high levels of transmission across host species, and indicate that the role of dogs should be considered when planning control programs. Furthermore, a regional approach to treatment programs is recommended where human migration is extensive.

Research paper thumbnail of Population genetics of multi-host parasites – the case for molecular epidemiological studies of Schistosoma japonicum using larval stages from naturally infected hosts

Parasitology, 2005

Population genetics of multi-host pathogens offers great potential for the understanding of their... more Population genetics of multi-host pathogens offers great potential for the understanding of their complex epidemiology but care must be taken to ensure that the sampling procedure does not bias estimates of population indices. The transfer of material to laboratory passage, in particular, runs the risk of bottlenecking and imposing non-random host-induced selection pressures according to the hosts used in passage. We present a novel technique allowing single-locus microsatellite genotyping of the naturally sampled larval stages, enabling unbiased population genetic studies of the multi-host zoonotic parasite Schistosoma japonicum. The utility of these larval genotyping methods for molecular epidemiological studies are illustrated in results from 3 separate data sets. In the first data set, potential loss of alleles based on the definitive host species used for laboratory maintenance was identified by comparing adult worm populations derived from mice and rabbits infected with cercar...

Research paper thumbnail of Development and application of an ethically and epidemiologically advantageous assay for the multi-locus microsatellite analysis of Schistosoma mansoni

Parasitology, 2006

Non-availability of adult worms from living hosts remains a key problem in population genetic stu... more Non-availability of adult worms from living hosts remains a key problem in population genetic studies of schistosomes. Indirect sampling involving passage through laboratory animals presents significant ethical and practical drawbacks, and may result in sampling biases such as bottlenecking processes and/or host-induced selection pressures. The novel techniques reported here for sampling, storage and multi-locus microsatellite analysis of larval Schistosoma mansoni, allowing genotyping of up to 7 microsatellite loci from a single larva, circumvent these problems. The utility of these assays and the potential problems of laboratory passage, were evaluated using 7 S. mansoni population isolates collected from school-children in the Hoima district of Uganda, by comparing the associated field-collected miracidia with adult worms and miracidia obtained from a single generation in laboratory mice. Analyses of laboratory-passaged material erroneously indicated the presence of geographical ...

Research paper thumbnail of An insight into the genetic variation of Schistosoma japonicum in mainland China using DNA microsatellite markers

Molecular Ecology, 2005

This study presents the first microsatellite investigation into the level of genetic variation am... more This study presents the first microsatellite investigation into the level of genetic variation among Schistosoma japonicum from different geographical origins. S. japonicum isolates were obtained from seven endemic provinces across mainland China: Zhejiang (Jiashan County), Anhui (Guichi County), Jiangxi (Yongxiu County), Hubei (Wuhan County), Hunan (Yueyang area), Sichuan 1 (Maoshan County), Sichuan 2 (Tianquan County), Yunnan (Dali County), and also one province in the Philippines (Sorsogon). DNA from 20 individuals from each origin were screened against 11 recently isolated and characterized S. japonicum microsatellites, and a set of nine loci were selected based on their polymorphic information content. High levels of polymorphism were obtained between and within population samples, with Chinese and Philippine strains appearing to follow different lineages, and with distinct branching between provinces. Moreover, across mainland China, genotype clustering appeared to be related to habitat type and /or intermediate host morph. These results highlight the suitability of microsatellites for population genetic studies of S. japonicum and suggest that there may be different strains of S. japonicum circulating in mainland China.

Research paper thumbnail of Does multiple hosts mean multiple parasites? Population genetic structure of Schistosoma japonicum between definitive host species

International Journal for Parasitology, 2006

Multi-host parasites, those capable of infecting more than one species of host, are responsible f... more Multi-host parasites, those capable of infecting more than one species of host, are responsible for the majority of all zoonotic, emerging or persistent human and animal diseases and are considered one of the major challenges for the biomedical sciences in the 21st century. We characterized the population structure of the multi-host parasite Schistosoma japonicum in relation to its definitive host species by genotyping miracidia collected from humans and domestic animals across five villages around the Yangtze River in Anhui Province, mainland China, using microsatellite markers. High levels of polymorphisms were observed and two main genetic clusters were identified which separated water buffalo, cattle and humans from goats, pigs, dogs and cats. We thereby believe that we present the first evidence of definitive host-based genetic variation in Schistosoma japonicum which has important epidemiological, evolutionary, medical and veterinary implications.

Research paper thumbnail of Tectonomagmatic setting of lava packages in the Mandla lobe of the eastern Deccan volcanic province, India: palaeomagnetism and magnetostratigraphic evidence

Geological Society, London, Special Publications, 2016

Flow-by-flow palaeomagnetic measurements of 37 lava flows in the 900 m-thick, isolated lava pile ... more Flow-by-flow palaeomagnetic measurements of 37 lava flows in the 900 m-thick, isolated lava pile around Mandla in the eastern Deccan Volcanic Province (DVP) reveals multiple magnetic polarity events: implying C29n–C28r–C28n magnetostratigraphy. Magnetic polarity results when traced out from section to section, maintaining the order of superposition, show juxtaposition of lava packages with distinct characters near Deori (e.g. flows 1–4 abated against flows 5–14) and the Dindori areas. At Dindori and towards its south, the distinct lava packages (e.g. flows 15–27 and flows 28–37) are juxtaposed along the course of Narmada river. It is explained by the presence of four normal post-Deccan faults in the Nagapahar, Kundam–Deori, Dindori and Badargarh–Amarkantak sectors: thus, signifying structural complexity with vertical shifts or offset of 150–300 m. Magnetic chron reversals in conjunction with field and chemical data support these findings. Further, these lavas are compositionally aki...

Research paper thumbnail of Physils and organic matter-base palaeoenvironmental records of the K/Pg boundary transition from the late Cretaceous-early Palaeogene succession of the Um-Sohryngkew River section of Meghalaya, India

Chemie der Erde - Geochemistry, 2015

Investigación centrada en la caracterización geomorfológica y sedimentológica de los depósitos eó... more Investigación centrada en la caracterización geomorfológica y sedimentológica de los depósitos eólicos de Cabo San Román (estado Falcón), con el fin de generar información que permita comprender la evolución y dinámica del referido sistema dunar. Se empleó un modelo metodológico de campo, no experimental, en un nivel descriptivo, cumpliendo las fases de campo, laboratorio y oficina. Los resultados determinaron que el área se divide en dos zonas con dunas activas, constituidas por cuarzos con talla de arena fina. En la zona oriental, el material presenta un alto contenido de carbonatos en contraste con la zona occidental. El fuerte oleaje y los vientos Alisios, son los encargados del origen de estas geoformas, mientras que la deflación, corrosión y abrasión, constituyen los principales procesos vinculados a la reducción de la cobertura en la zona occidental, por su parte, hacia el oriente, se experimenta un crecimiento en los últimos 32 años.

Research paper thumbnail of Mineral chemistry of clays associated with the Late Cretaceous-early Palaeogene succession of the Um-Sohryngkew river section of Meghalaya, India: Palaeoenvironmental inferences and K/Pg transition

Journal of the Geological Society of India, 2015

A unique, continuous, shallow marine succession within the Langpar Formation in the Um-Sohryngkew... more A unique, continuous, shallow marine succession within the Langpar Formation in the Um-Sohryngkew river section of Meghalaya contains late Maastrichtian through early Danian planktonic foraminiferal biozones (CF4-P1a) and the K/Pg boundary (between CF1 and P0). To resolve compositional overlap [in the three-fold clay mineral based sub-divisions of the section (include 1–2 mm thick yellowish brown clay layer in biozone CF3)] and to understand paleoenvironmental conditions prevalent at the time of K/Pg transition, micro-structural and compositional studies were carried out. The paper discusses accurate compositional limits of solid solubility in smectite and illite. Clay morphological attributes distinctly vary with the changes in the biozonation. Major oxide data plots for the litho-units (samples JP1-16) over binary diagrams, show clustering of plots within the illite compositional field. Plots based on structural formulae and layer charges of illite and kaolinite rich clays (from CF4 to Pla biozones), show closeness with the clay data fields of Agost, Caravaca, Petriccio and El-Kef K/T boundary sections as their charge occupancies at tetrahedral (Zt), octahedral (Zo) and interlayer (Zi) sites are similar. Thermodynamic data plots over ternary [AR23+Si3O10(OH)2 − R23+SiO4O10(OH)2 − A3AlSi4O10(OH)2] diagram, clustered within the illite compositional fields. Majority of illites shows high K values. They represent occasionally higher Altet. and lower Aloct. layer charges. Calculated palaeotemperature values for illite (from the CF4 to Pla zones) vary from 68 – 232ºC. Sudden rise in the temperature (>140ºC) of illite formation noticed in the upper part of the biozone CF3 (sample JP-12) is comparable to the K/T boundary layer of Caravaca section. Wide variation in the humid tropical to arid-semiarid climatic and thermal (diagenetic to low grade metamorphic) conditions noticed across the succession is possiby linked with the contemporaneous Abor / Deccan volcanic activities (at the time of their deposition) as also reflected in their clay layer [Si (2.95–3.68)] and interlayer [K+Na (0.4–4.61)] charges.

Research paper thumbnail of Polycyclic aromatic hydrocarbon compound excursions and K/Pg transition in the late Cretaceous–early Palaeogene succession of the Um Sohryngkew river section, Meghalaya

Research paper thumbnail of Mineral chemistry of clays associated with the Jhilmili intertrappean bed in the eastern Deccan volcanic province: Palaeoenvironmental inferences and KTB transition

Journal of the Geological Society of India, 2013

ABSTRACT Jhilmili intertrappean bed (∼13 m thick) attains its significance with the recent discov... more ABSTRACT Jhilmili intertrappean bed (∼13 m thick) attains its significance with the recent discovery of brackish water ostrocod and planktonic foraminifera fossils (Keller et al. 2009; Khosala et al. 2009). Present XRD data revealed abundance of montmorillonite > montmorillonite/chlorite mixed layer > palygorskite in five physically distinct lithounits namely: (a) lower chocolate brown siltstone with green patches, followed by (b) brick red clayey siltstone, (c) greenish grey clay, (d) yellowish brown clay and (e) uppermost olive grey to dark brown silt layers in the successionrepresent higher weathering indices and annual precipitation, reflecting cyclic, but longer spells of weathering. Occurrence of M/C mixed layer with the smectite in Jhilmili area is suggestive of their derivation from the later, whilst montmorillonite to palygorskite transformation is ascribed to the drastic changes in the humid to arid climate, where former served as a source of Al and some of the Si and Mg ions for the later. Jhilmili and Anjar clays represent similar charge occupancies at different sites, but later contains relatively higher amount of palygorskite, formed in the arid environment. Majority of the trace elemental data plots for Jhilmili clays lie within the upper and lower limits of infra (Lametas)-/inter-trappeans clays. The continuous release of Cu throughout the succession (mainly in the palygorskite dominated clays) indicates oxidizing conditions. PAAS normalized REE data plots for these clays show progressive enrichment in the HREE contents in the lower part, but, upper part of the succession is marked by positive cerium anomaly, reflecting oxidizing conditions prevailed at the later stage of the succession. These conditions continued, but, were not conducive to HREE enrichment as evidenced by their depletion in the upper part of the succession. The Ce anomaly observed in the middle part of the succession is similar to that form by continental weathering of the basalt, ascribed to Ce precipitation in the oxic environment, thus suggestive of drastic changes in the oxidizing conditions. Thermodynamic data-sets for Jhilmili clays show I/S mixed layer and celadonite compositions, whereas, Jabalpur infra-/inter-trappean clays correspond to Mg smectites and celadonite end members, thus, representing compositional commonality with those of the other clays derived from the continental weathering of basalt protolith. Jhilmili smectites and smectite-chlorite mixtures show compositional similarity with the dioctahedral and trioctahedral smectites and the smectites formed at 250°C, having compositions between trioctahedral smectite and chlorite, thus, assigning high temperatures for their formation, where the heat required for the formation of these clays was possibly derived from the hydrothermal fluids, associated with the Deccan volcanism.

Research paper thumbnail of Petrography and Mineral Chemistry of Neovolcanics Occurring between Pacific and Nazca Plate Boundaries by S.K. Pandey, J.P. Shrivastava and G.S. Roonwal. Jour. Geol. Soc. India, v.74, 2009, pp.559–572

Journal of the Geological Society of India, 2010

Research paper thumbnail of Clay mineralogical studies on Bijawars of the Sonrai basin: Palaeoenvironmental implications and inferences on the uranium mineralization

Journal of the Geological Society of India, 2012

Research paper thumbnail of Trace elements geochemistry and petrogenesis of basalt from the southern part of the East Pacific Rise

Journal of the Geological Society of India, 2013

ABSTRACT Trace element geochemistry of basalt samples collected from 6°S-24°S of the southern EPR... more ABSTRACT Trace element geochemistry of basalt samples collected from 6°S-24°S of the southern EPR, representing a super-fast spreading axis is discussed. Trace element data classify these basalts into Normal and Transitional types of MORB, however, LREE enrichment is also observed in few of them. Chondrite normalized REE data plots show highly fractionated nature of these lavas, suggesting their derivation from the primitive mantle source. Petrogenetic modeling of the data suggests variation in the solidus pressure (14–20 kb.) and temperature (1316–1425°C), where 15 to 20% partial melting of the mantle is accountable for the generation of the melt. The pressure and temperature conditions at the beginning of the mantle melting were high along higher latitudes (24°S of EPR), but it gradually lowered down in the lower latitudinal areas (6°S of EPR), supporting for the presence of passively rising upper mantle beneath the Southern EPR.

Research paper thumbnail of Occurrence of ferroan trevorite within olivine megacrysts of the MORB from Southern East Pacific Rise

CURRENT SCIENCE, 2008

ABSTRACT 1 that forms the Pa- cific and Nazca Plate boundaries. Previous studies 2-7 on this axis... more ABSTRACT 1 that forms the Pa- cific and Nazca Plate boundaries. Previous studies 2-7 on this axis pointed out large-scale mantle heterogeneity be- low the area (Figure 1 a). Samples were collected on- board the research vehicle Sonne during the German ex- pedition, GEOMETEP IV. The present work is related to major and trace (Ni and Cr) elements geochemistry, and optical and electron probe micro analysis (EPMA) of samples to understand nature of the mantle heterogeneity below the SEPR. Thus, the work is focused on a large transect (6°S-26°S) extending along the axis of the SEPR. In all, 59 samples were collected from the thirty sampling sites 122D to 412G over this transect. Petrography and modal analyses were carried out for 37 samples (Table 1). For the latter, an Image Analyzer (Leica Make, Qwin DMRX model) was used. It is observed that the high modal olivine (>6.73%) values are restricted to a group of six samples from 128G and all sample from 122D, 141G and 154D sampling sites. Samples having unusually high oli- vine (Table 2) content reflecting primitive nature are sig- nificant and have been considered for the EPMA. Physical and optical properties of the constituent min- eral phases along with the modal data are presented in Table 1. A microscopic study revealed the presence of olivine megacrysts with interspersed spinel grains (Figure 2 a). Relict, highly deformed, cubic, sub-rounded to rounded spinel grains that lie within the olivine mega- crysts show high relief. Major oxide data (Table 3) for these samples (obtained by XRF analysis) show high (>7%) MgO values. These samples also represent high (>60) values for their Mg number. The data when plotted as a total alkali vs silica (TAS) diagram (Figure 3), show that these are basalt and basaltic andesite. Calculated norms also revealed the same result (Table 3). The data obtained from these samples show high Ni values Figure 1. Location map of the study area in the South Pacific Ocean (modified after Naar and Hey

Research paper thumbnail of Chemico-mineralogical attributes of clays from the late Cretaceous–early Palaeogene succession of the Um Sohryngkew river section of Meghalaya, India: Palaeoenvironmental inferences and the K/Pg boundary

Cretaceous Research, 2013

Research paper thumbnail of GC-MS raw data

Research paper thumbnail of Enhanced Biotic Recovery Through KPB Transition: Evidence from the Mahadeo-Cherrapunji Section, Meghalaya, India

Research paper thumbnail of Cretaceous/Palaeogene boundary transition induced lattice defects in illite and kaolinite associated with the Um-Sohryngkew river section, Meghalaya, India

Solid Earth Sciences, 2020

Cetaceous-Palaeogene Boundary (KPB) transition records restricted to a unique, continuous, late M... more Cetaceous-Palaeogene Boundary (KPB) transition records restricted to a unique, continuous, late Maastrichtian-early Danian, shallow marine Um Sohryngkew river succession (bearing planktonic foraminifers' CF4 to P1a biozones) have not been studied in detail. Earlier studies sub-divided it into lower, middle and upper parts, defined by the dominance of illite> illite/smectite; illite>kaolinite> montmorillonite and kaolinite > montmorillonite assemblages, respectively. However, limited studies were carried out on the KPB transition events, particularly for those reproduced in the illite (C2/m) and kaolinite (P1) lattice structures. Thus, illite a nd kaolinite cell parameters and interatomic distances have been studied to understand KPB transition events. For this purpose, layer-wise clay (0.2–2 μm) separates were analyzed by X-ray diffraction method and subjected to Rietveld refinement. Obtained data show substantial expansion in the c-axis of the kaolinite grains assoc...

Research paper thumbnail of Evidence of biotic recovery through the Cretaceous/Palaeogene transition from the Mahadeo-Cherrapunji succession in the Meghalaya shelf, India

Palaeobiodiversity and Palaeoenvironments

Earlier studies on the Mahadeo-Cherrapunji road (MCR) section have documented the Cretaceous-Pala... more Earlier studies on the Mahadeo-Cherrapunji road (MCR) section have documented the Cretaceous-Palaeogene Boundary (KPB ca.6 6 Ma), but rare data exist on the Deccan volcanism induced KPB transition and related faunal crises. The environmental stress on biota has been postulated as the main cause of mass extinction. Thus, the study of organic matter (OM) entrapped in the Maastrichtian-Danian shelf sediments has attained importance, although the existing data is inadequate. In this situation, layer-wise n-alkanes and nfatty acids analyses were carried out using GC-MS. Obtained data show sudden increase in the short chain n-alkane (SCA~6-fold), nfatty acid (FA) and hopane (> sterane) concentrations. This suggests enhanced continental runoff and soil bacteria biomass passage into the marine realm. Comparing the MCR to the published KPB bearing shallow-marine facies of the Um-Sohryngkew River (USR) section data, we document high SCA and FA contents together with the abundance of the even carbon numbered SCA (n-C 16 and n-C 18). This suggests thermal degradation and partial combustion of non-woody biomass. The presence of C 17 n-alkane and hopane is indicative of their derivation from the algae, fungi and bacteria. A sudden SCA concentration increase coincides with the reported major foraminifers' extinction between the CF1 and P0 biozones of the MCR section. Further, a similar anomaly exists in the lower part of the CF3 biozone of the USR section and precedes extinction of the main foraminifers' assemblages. The excursions in SCA content along with hopane and FA are matching well with the major incidences of the Deccan volcanic episodes and convergence of the Indian-plate with the Eurasian plate occurred at 66 Ma (Beck et al. 1995) and with the Burmese-plate during Maastrichtian (Wakita and Metcalfe 2005). These events were responsible for the seawater disturbances, eustatic and depositional changes, including the retreat of the Tethys. Thus, a combination of extra-basinal and tectono-thermal events together with the greenhouse effects led to unexpected temperature rise and recurrent local sea-level changes that may have resulted in stress and faunal crisis.

Research paper thumbnail of Comparative Evaluation of Biodegradation Potential of Arthrobacter chlorophenolicus and Microbacterium esteraromaticum for Cyclic Nitramine Explosive Octahydro-1 , 3 , 5 , 7-Tetranitro-1 , 3 , 5 . 7-Tetrazocine ( HMX )

Best known for its explosive properties, HMX is also an environmental pollutant of concern contam... more Best known for its explosive properties, HMX is also an environmental pollutant of concern contaminating numerous military sites in India and world around. Many years of manufacture, processing and use of Octahydro1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX) in military installations worldwide have caused widespread contamination of water, soil and sediments. Pollution of the environment by munitions occurs primarily through the discharge of untreated process wastes and residues from explosives manufacturing and processing plants. HMX, a possible human carcinogen, is toxic to biological system, and is recalcitrant to degradation. Therefore, the removal of HMX from explosive contaminated environment is crucial for the safety of ecosystems and human health. Among the several existing remediation approaches, microbial biodegradation is the most economical and eco-friendly cleanup option. In this study, we evaluated biodegradation efficiency of two bacteria viz. Arthrobacter chlor...

Research paper thumbnail of Population Genetics of Schistosoma japonicum within the Philippines Suggest High Levels of Transmission between Humans and Dogs

PLoS Neglected Tropical Diseases, 2008

Background: Schistosoma japonicum, which remains a major public health problem in the Philippines... more Background: Schistosoma japonicum, which remains a major public health problem in the Philippines and mainland China, is the only schistosome species for which zoonotic transmission is considered important. While bovines are suspected as the main zoonotic reservoir in parts of China, the relative contributions of various non-human mammals to S. japonicum transmission in the Philippines remain to be determined. We examined the population genetics of S. japonicum in the Philippines in order to elucidate transmission patterns across host species and geographic areas. Methodology/Principal Findings: S. japonicum miracidia (hatched from eggs within fecal samples) from humans, dogs, pigs and rats, and cercariae shed from snail-intermediate hosts, were collected across two geographic areas of Samar Province. Individual isolates were then genotyped using seven multiplexed microsatellite loci. Wright's F ST values and phylogenetic trees calculated for parasite populations suggest a high frequency of parasite gene-flow across definitive host species, particularly between dogs and humans. Parasite genetic differentiation between areas was not evident at the definitive host level, possibly suggesting frequent import and export of infections between villages, although there was some evidence of geographic structuring at the snail-intermediate host level. Conclusions/Significance: These results suggest very high levels of transmission across host species, and indicate that the role of dogs should be considered when planning control programs. Furthermore, a regional approach to treatment programs is recommended where human migration is extensive.

Research paper thumbnail of Population genetics of multi-host parasites – the case for molecular epidemiological studies of Schistosoma japonicum using larval stages from naturally infected hosts

Parasitology, 2005

Population genetics of multi-host pathogens offers great potential for the understanding of their... more Population genetics of multi-host pathogens offers great potential for the understanding of their complex epidemiology but care must be taken to ensure that the sampling procedure does not bias estimates of population indices. The transfer of material to laboratory passage, in particular, runs the risk of bottlenecking and imposing non-random host-induced selection pressures according to the hosts used in passage. We present a novel technique allowing single-locus microsatellite genotyping of the naturally sampled larval stages, enabling unbiased population genetic studies of the multi-host zoonotic parasite Schistosoma japonicum. The utility of these larval genotyping methods for molecular epidemiological studies are illustrated in results from 3 separate data sets. In the first data set, potential loss of alleles based on the definitive host species used for laboratory maintenance was identified by comparing adult worm populations derived from mice and rabbits infected with cercar...

Research paper thumbnail of Development and application of an ethically and epidemiologically advantageous assay for the multi-locus microsatellite analysis of Schistosoma mansoni

Parasitology, 2006

Non-availability of adult worms from living hosts remains a key problem in population genetic stu... more Non-availability of adult worms from living hosts remains a key problem in population genetic studies of schistosomes. Indirect sampling involving passage through laboratory animals presents significant ethical and practical drawbacks, and may result in sampling biases such as bottlenecking processes and/or host-induced selection pressures. The novel techniques reported here for sampling, storage and multi-locus microsatellite analysis of larval Schistosoma mansoni, allowing genotyping of up to 7 microsatellite loci from a single larva, circumvent these problems. The utility of these assays and the potential problems of laboratory passage, were evaluated using 7 S. mansoni population isolates collected from school-children in the Hoima district of Uganda, by comparing the associated field-collected miracidia with adult worms and miracidia obtained from a single generation in laboratory mice. Analyses of laboratory-passaged material erroneously indicated the presence of geographical ...

Research paper thumbnail of An insight into the genetic variation of Schistosoma japonicum in mainland China using DNA microsatellite markers

Molecular Ecology, 2005

This study presents the first microsatellite investigation into the level of genetic variation am... more This study presents the first microsatellite investigation into the level of genetic variation among Schistosoma japonicum from different geographical origins. S. japonicum isolates were obtained from seven endemic provinces across mainland China: Zhejiang (Jiashan County), Anhui (Guichi County), Jiangxi (Yongxiu County), Hubei (Wuhan County), Hunan (Yueyang area), Sichuan 1 (Maoshan County), Sichuan 2 (Tianquan County), Yunnan (Dali County), and also one province in the Philippines (Sorsogon). DNA from 20 individuals from each origin were screened against 11 recently isolated and characterized S. japonicum microsatellites, and a set of nine loci were selected based on their polymorphic information content. High levels of polymorphism were obtained between and within population samples, with Chinese and Philippine strains appearing to follow different lineages, and with distinct branching between provinces. Moreover, across mainland China, genotype clustering appeared to be related to habitat type and /or intermediate host morph. These results highlight the suitability of microsatellites for population genetic studies of S. japonicum and suggest that there may be different strains of S. japonicum circulating in mainland China.

Research paper thumbnail of Does multiple hosts mean multiple parasites? Population genetic structure of Schistosoma japonicum between definitive host species

International Journal for Parasitology, 2006

Multi-host parasites, those capable of infecting more than one species of host, are responsible f... more Multi-host parasites, those capable of infecting more than one species of host, are responsible for the majority of all zoonotic, emerging or persistent human and animal diseases and are considered one of the major challenges for the biomedical sciences in the 21st century. We characterized the population structure of the multi-host parasite Schistosoma japonicum in relation to its definitive host species by genotyping miracidia collected from humans and domestic animals across five villages around the Yangtze River in Anhui Province, mainland China, using microsatellite markers. High levels of polymorphisms were observed and two main genetic clusters were identified which separated water buffalo, cattle and humans from goats, pigs, dogs and cats. We thereby believe that we present the first evidence of definitive host-based genetic variation in Schistosoma japonicum which has important epidemiological, evolutionary, medical and veterinary implications.

Research paper thumbnail of Tectonomagmatic setting of lava packages in the Mandla lobe of the eastern Deccan volcanic province, India: palaeomagnetism and magnetostratigraphic evidence

Geological Society, London, Special Publications, 2016

Flow-by-flow palaeomagnetic measurements of 37 lava flows in the 900 m-thick, isolated lava pile ... more Flow-by-flow palaeomagnetic measurements of 37 lava flows in the 900 m-thick, isolated lava pile around Mandla in the eastern Deccan Volcanic Province (DVP) reveals multiple magnetic polarity events: implying C29n–C28r–C28n magnetostratigraphy. Magnetic polarity results when traced out from section to section, maintaining the order of superposition, show juxtaposition of lava packages with distinct characters near Deori (e.g. flows 1–4 abated against flows 5–14) and the Dindori areas. At Dindori and towards its south, the distinct lava packages (e.g. flows 15–27 and flows 28–37) are juxtaposed along the course of Narmada river. It is explained by the presence of four normal post-Deccan faults in the Nagapahar, Kundam–Deori, Dindori and Badargarh–Amarkantak sectors: thus, signifying structural complexity with vertical shifts or offset of 150–300 m. Magnetic chron reversals in conjunction with field and chemical data support these findings. Further, these lavas are compositionally aki...

Research paper thumbnail of Physils and organic matter-base palaeoenvironmental records of the K/Pg boundary transition from the late Cretaceous-early Palaeogene succession of the Um-Sohryngkew River section of Meghalaya, India

Chemie der Erde - Geochemistry, 2015

Investigación centrada en la caracterización geomorfológica y sedimentológica de los depósitos eó... more Investigación centrada en la caracterización geomorfológica y sedimentológica de los depósitos eólicos de Cabo San Román (estado Falcón), con el fin de generar información que permita comprender la evolución y dinámica del referido sistema dunar. Se empleó un modelo metodológico de campo, no experimental, en un nivel descriptivo, cumpliendo las fases de campo, laboratorio y oficina. Los resultados determinaron que el área se divide en dos zonas con dunas activas, constituidas por cuarzos con talla de arena fina. En la zona oriental, el material presenta un alto contenido de carbonatos en contraste con la zona occidental. El fuerte oleaje y los vientos Alisios, son los encargados del origen de estas geoformas, mientras que la deflación, corrosión y abrasión, constituyen los principales procesos vinculados a la reducción de la cobertura en la zona occidental, por su parte, hacia el oriente, se experimenta un crecimiento en los últimos 32 años.

Research paper thumbnail of Mineral chemistry of clays associated with the Late Cretaceous-early Palaeogene succession of the Um-Sohryngkew river section of Meghalaya, India: Palaeoenvironmental inferences and K/Pg transition

Journal of the Geological Society of India, 2015

A unique, continuous, shallow marine succession within the Langpar Formation in the Um-Sohryngkew... more A unique, continuous, shallow marine succession within the Langpar Formation in the Um-Sohryngkew river section of Meghalaya contains late Maastrichtian through early Danian planktonic foraminiferal biozones (CF4-P1a) and the K/Pg boundary (between CF1 and P0). To resolve compositional overlap [in the three-fold clay mineral based sub-divisions of the section (include 1–2 mm thick yellowish brown clay layer in biozone CF3)] and to understand paleoenvironmental conditions prevalent at the time of K/Pg transition, micro-structural and compositional studies were carried out. The paper discusses accurate compositional limits of solid solubility in smectite and illite. Clay morphological attributes distinctly vary with the changes in the biozonation. Major oxide data plots for the litho-units (samples JP1-16) over binary diagrams, show clustering of plots within the illite compositional field. Plots based on structural formulae and layer charges of illite and kaolinite rich clays (from CF4 to Pla biozones), show closeness with the clay data fields of Agost, Caravaca, Petriccio and El-Kef K/T boundary sections as their charge occupancies at tetrahedral (Zt), octahedral (Zo) and interlayer (Zi) sites are similar. Thermodynamic data plots over ternary [AR23+Si3O10(OH)2 − R23+SiO4O10(OH)2 − A3AlSi4O10(OH)2] diagram, clustered within the illite compositional fields. Majority of illites shows high K values. They represent occasionally higher Altet. and lower Aloct. layer charges. Calculated palaeotemperature values for illite (from the CF4 to Pla zones) vary from 68 – 232ºC. Sudden rise in the temperature (>140ºC) of illite formation noticed in the upper part of the biozone CF3 (sample JP-12) is comparable to the K/T boundary layer of Caravaca section. Wide variation in the humid tropical to arid-semiarid climatic and thermal (diagenetic to low grade metamorphic) conditions noticed across the succession is possiby linked with the contemporaneous Abor / Deccan volcanic activities (at the time of their deposition) as also reflected in their clay layer [Si (2.95–3.68)] and interlayer [K+Na (0.4–4.61)] charges.

Research paper thumbnail of Polycyclic aromatic hydrocarbon compound excursions and K/Pg transition in the late Cretaceous–early Palaeogene succession of the Um Sohryngkew river section, Meghalaya

Research paper thumbnail of Mineral chemistry of clays associated with the Jhilmili intertrappean bed in the eastern Deccan volcanic province: Palaeoenvironmental inferences and KTB transition

Journal of the Geological Society of India, 2013

ABSTRACT Jhilmili intertrappean bed (∼13 m thick) attains its significance with the recent discov... more ABSTRACT Jhilmili intertrappean bed (∼13 m thick) attains its significance with the recent discovery of brackish water ostrocod and planktonic foraminifera fossils (Keller et al. 2009; Khosala et al. 2009). Present XRD data revealed abundance of montmorillonite > montmorillonite/chlorite mixed layer > palygorskite in five physically distinct lithounits namely: (a) lower chocolate brown siltstone with green patches, followed by (b) brick red clayey siltstone, (c) greenish grey clay, (d) yellowish brown clay and (e) uppermost olive grey to dark brown silt layers in the successionrepresent higher weathering indices and annual precipitation, reflecting cyclic, but longer spells of weathering. Occurrence of M/C mixed layer with the smectite in Jhilmili area is suggestive of their derivation from the later, whilst montmorillonite to palygorskite transformation is ascribed to the drastic changes in the humid to arid climate, where former served as a source of Al and some of the Si and Mg ions for the later. Jhilmili and Anjar clays represent similar charge occupancies at different sites, but later contains relatively higher amount of palygorskite, formed in the arid environment. Majority of the trace elemental data plots for Jhilmili clays lie within the upper and lower limits of infra (Lametas)-/inter-trappeans clays. The continuous release of Cu throughout the succession (mainly in the palygorskite dominated clays) indicates oxidizing conditions. PAAS normalized REE data plots for these clays show progressive enrichment in the HREE contents in the lower part, but, upper part of the succession is marked by positive cerium anomaly, reflecting oxidizing conditions prevailed at the later stage of the succession. These conditions continued, but, were not conducive to HREE enrichment as evidenced by their depletion in the upper part of the succession. The Ce anomaly observed in the middle part of the succession is similar to that form by continental weathering of the basalt, ascribed to Ce precipitation in the oxic environment, thus suggestive of drastic changes in the oxidizing conditions. Thermodynamic data-sets for Jhilmili clays show I/S mixed layer and celadonite compositions, whereas, Jabalpur infra-/inter-trappean clays correspond to Mg smectites and celadonite end members, thus, representing compositional commonality with those of the other clays derived from the continental weathering of basalt protolith. Jhilmili smectites and smectite-chlorite mixtures show compositional similarity with the dioctahedral and trioctahedral smectites and the smectites formed at 250°C, having compositions between trioctahedral smectite and chlorite, thus, assigning high temperatures for their formation, where the heat required for the formation of these clays was possibly derived from the hydrothermal fluids, associated with the Deccan volcanism.

Research paper thumbnail of Petrography and Mineral Chemistry of Neovolcanics Occurring between Pacific and Nazca Plate Boundaries by S.K. Pandey, J.P. Shrivastava and G.S. Roonwal. Jour. Geol. Soc. India, v.74, 2009, pp.559–572

Journal of the Geological Society of India, 2010

Research paper thumbnail of Clay mineralogical studies on Bijawars of the Sonrai basin: Palaeoenvironmental implications and inferences on the uranium mineralization

Journal of the Geological Society of India, 2012

Research paper thumbnail of Trace elements geochemistry and petrogenesis of basalt from the southern part of the East Pacific Rise

Journal of the Geological Society of India, 2013

ABSTRACT Trace element geochemistry of basalt samples collected from 6°S-24°S of the southern EPR... more ABSTRACT Trace element geochemistry of basalt samples collected from 6°S-24°S of the southern EPR, representing a super-fast spreading axis is discussed. Trace element data classify these basalts into Normal and Transitional types of MORB, however, LREE enrichment is also observed in few of them. Chondrite normalized REE data plots show highly fractionated nature of these lavas, suggesting their derivation from the primitive mantle source. Petrogenetic modeling of the data suggests variation in the solidus pressure (14–20 kb.) and temperature (1316–1425°C), where 15 to 20% partial melting of the mantle is accountable for the generation of the melt. The pressure and temperature conditions at the beginning of the mantle melting were high along higher latitudes (24°S of EPR), but it gradually lowered down in the lower latitudinal areas (6°S of EPR), supporting for the presence of passively rising upper mantle beneath the Southern EPR.

Research paper thumbnail of Occurrence of ferroan trevorite within olivine megacrysts of the MORB from Southern East Pacific Rise

CURRENT SCIENCE, 2008

ABSTRACT 1 that forms the Pa- cific and Nazca Plate boundaries. Previous studies 2-7 on this axis... more ABSTRACT 1 that forms the Pa- cific and Nazca Plate boundaries. Previous studies 2-7 on this axis pointed out large-scale mantle heterogeneity be- low the area (Figure 1 a). Samples were collected on- board the research vehicle Sonne during the German ex- pedition, GEOMETEP IV. The present work is related to major and trace (Ni and Cr) elements geochemistry, and optical and electron probe micro analysis (EPMA) of samples to understand nature of the mantle heterogeneity below the SEPR. Thus, the work is focused on a large transect (6°S-26°S) extending along the axis of the SEPR. In all, 59 samples were collected from the thirty sampling sites 122D to 412G over this transect. Petrography and modal analyses were carried out for 37 samples (Table 1). For the latter, an Image Analyzer (Leica Make, Qwin DMRX model) was used. It is observed that the high modal olivine (>6.73%) values are restricted to a group of six samples from 128G and all sample from 122D, 141G and 154D sampling sites. Samples having unusually high oli- vine (Table 2) content reflecting primitive nature are sig- nificant and have been considered for the EPMA. Physical and optical properties of the constituent min- eral phases along with the modal data are presented in Table 1. A microscopic study revealed the presence of olivine megacrysts with interspersed spinel grains (Figure 2 a). Relict, highly deformed, cubic, sub-rounded to rounded spinel grains that lie within the olivine mega- crysts show high relief. Major oxide data (Table 3) for these samples (obtained by XRF analysis) show high (>7%) MgO values. These samples also represent high (>60) values for their Mg number. The data when plotted as a total alkali vs silica (TAS) diagram (Figure 3), show that these are basalt and basaltic andesite. Calculated norms also revealed the same result (Table 3). The data obtained from these samples show high Ni values Figure 1. Location map of the study area in the South Pacific Ocean (modified after Naar and Hey

Research paper thumbnail of Chemico-mineralogical attributes of clays from the late Cretaceous–early Palaeogene succession of the Um Sohryngkew river section of Meghalaya, India: Palaeoenvironmental inferences and the K/Pg boundary

Cretaceous Research, 2013

Research paper thumbnail of GC-MS raw data

Research paper thumbnail of Enhanced Biotic Recovery Through KPB Transition: Evidence from the Mahadeo-Cherrapunji Section, Meghalaya, India

Research paper thumbnail of Cretaceous/Palaeogene boundary transition induced lattice defects in illite and kaolinite associated with the Um-Sohryngkew river section, Meghalaya, India

Solid Earth Sciences, 2020

Cetaceous-Palaeogene Boundary (KPB) transition records restricted to a unique, continuous, late M... more Cetaceous-Palaeogene Boundary (KPB) transition records restricted to a unique, continuous, late Maastrichtian-early Danian, shallow marine Um Sohryngkew river succession (bearing planktonic foraminifers' CF4 to P1a biozones) have not been studied in detail. Earlier studies sub-divided it into lower, middle and upper parts, defined by the dominance of illite> illite/smectite; illite>kaolinite> montmorillonite and kaolinite > montmorillonite assemblages, respectively. However, limited studies were carried out on the KPB transition events, particularly for those reproduced in the illite (C2/m) and kaolinite (P1) lattice structures. Thus, illite a nd kaolinite cell parameters and interatomic distances have been studied to understand KPB transition events. For this purpose, layer-wise clay (0.2–2 μm) separates were analyzed by X-ray diffraction method and subjected to Rietveld refinement. Obtained data show substantial expansion in the c-axis of the kaolinite grains assoc...