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Endophytes and Plant Secondary Metabolite Synthesis: Molecular and Evolutionary Perspective
No full textThe distribution of endophytes (fungal and bacterial) is ubiquitous and almost without exception; the endophytes have been reported from all tissues, including leaves, stems, roots, flowers and fruits. As typical symptomless organisms, in contrast to their pathogenic counterparts, they pose a serious challenge in explaining their continued maintenance in plants. How do plants tolerate them? And how do the endophytes contain the plant defences? But a more intriguing and enigmatic issue with many endophytes is the fact that they mimic the production of specific plant associated secondary metabolites (e.g. taxol, camptothecin and rohitukine) in culture, independent of the host tissue. Several theories including the possibility of horizontal gene transfer from the respective hosts have been proposed, but none has so far been supported. In this paper, we
critically review studies on endophytes producing plant secondary metabolites and explore the possible molecular mechanisms. By analysing the pathway genes for a few major metabolites, including taxol and camptothecin, we show that a far more intricate molecular mechanism might be involved in the production of the secondary
metabolites by the endophytes. We show that these molecular mechanisms could have arisen through the evolutionary interactions of the endophytes with their respective host plants. We discuss these findings in the context of the current interest in harnessing endophytes
as alternative sources of plant secondary metabolites
Science, Society and Risk in the Anthropocene
No full textThe culture of too much hygiene in rapid, unplanned
urbanising society with poor infrastructure exposes urban
spaces to a particular risk brought about by unchecked
use of technology. This article looks at the indiscriminate use of antibiotics and antibacterial consumer products, which form the aetiology for the emergence of new strains of antibiotic resistant bacteria (superbugs) in urban space, especially in waterbodies
Abundance and density estimates for common leopard Panthera pardus and clouded leopard Neofelis nebulosa in Manas National Park, Assam, India
No full textEffective conservation of rare carnivores requires
reliable estimates of population density for prioritizing
investments and assessing the effectiveness of conservation interventions. We used camera traps and capture–recapture analysis to provide the first reliable abundance and density estimates for the common leopard Panthera pardus and clouded leopard Neofelis nebulosa in Manas National Park, India. In 57 days of camera trapping, with a total of 4,275 camera-trap days, we photo-captured 27 individually identified common leopards (11 males, 13 females and three unidentified), and 16 clouded leopards (four males, five females and seven unidentified). The abundance estimates using the Mh jackknife and Pledger model Mh were 47.0 and 35.6, respectively, for the common leopard, and 21.0 and 25.0, respectively, for the clouded leopard. Density estimates using maximum likelihood spatiallyexplicit capture–recapture were 3.4 ± SE 0.82 and 4.73 ± SE 1.43 per 100 km2 for the common and clouded leopards, respectively. Spatially-explicit capture–recapture provided more realistic density estimates compared with those obtained from conventional methods. Our data indicates that camera trapping using a capture–recapture framework is an effective tool for assessing population sizes of cryptic and elusive carnivores such as the common and clouded leopards. The study has established a baseline for the longterm monitoring programme for large carnivores in Manas National Park
Forest Trees in Human Modified Landscapes: Ecological and Genetic Drivers of Recruitment Failure in Dysoxylum malabaricum (Meliaceae)
Get PDFTropical agro-forest landscapes are global priority areas for biodiversity conservation. Little is known about the ability of these landscapes to sustain large late successional forest trees upon which much forest biodiversity depends. These landscapes are subject to fragmentation and additional habitat degradation which may limit tree recruitment and thus compromise numerous ecosystem services including carbon storage and timber production. Dysoxylum malabaricum is a large canopy tree species in the Meliaceae, a family including many important tropical timber trees. This species is found in
highly fragmented forest patches within a complex agro-forest landscape of the Western Ghats biodiversity hot spot, South India. In this paper we combined a molecular assessment of inbreeding with ecological and demographic data to explore the multiple threats to recruitment of this tree species. An evaluation of inbreeding, using eleven microsatellite loci in 297 nursery-reared seedlings collected form low and high density forest patches embedded in an agro-forest matrix, shows that
mating between related individuals in low density patches leads to reduced seedling performance. By quantifying habitat degradation and tree recruitment within these forest patches we show that increasing canopy openness and the increased abundance of pioneer tree species lead to a general decline in the suitability of forest patches for the recruitment of D. malabaricum. We conclude that elevated inbreeding due to reduced adult tree density coupled with increased degradation of forest patches, limit the recruitment of this rare late successional tree species. Management strategies which maintain canopy cover and enhance local densities of adult trees in agro-forest mosaics will be required to ensure D. malabaricum persists in these landscapes. Our study highlights the need for a holistic understanding of the incipient processes that threaten populations of many important and rare tropical tree species in human dominated agro-forest landscapes
A cat among the dogs: leopard Panthera pardus diet in a human-dominated landscape in western Maharashtra, India
No full textThe ecology and predator–prey dynamics of large felids in the tropics have largely been studied in natural systems where wild ungulates constitute the majority of the prey base. However, human-dominated landscapes can be rich in potential prey for large carnivores because of the high density of domestic animals, especially in tropical countries where pastoralism is an important livelihood activity. We report the almost complete dependence of leopards Panthera pardus on domestic animals as prey in the crop lands of Ahmednagar district, Maharashtra, India. From analysis of 85 confirmed leopard scats, 87% of the leopard's prey biomass consisted of domestic animals, with 39% consisting of domestic dogs Canis lupus familiaris alone. The only wild species that occurred in the leopard's diet were rodents, small indian civet Viverricula indica, bonnet macaque Macaca radiata and other primates Semnopithecus spp., mongoose Herpestes spp., and birds. Interviews conducted in 77 households distributed randomly in the study area documented a high density of domestic animals: adult cattle Bos taurus, calves, goats Capra aegagrus, dogs and cats Felis catus occurred at densities of 169, 54, 174, 24 and 61 per km2, respectively. Ivlev's electivity index indicated that dogs and cats were over-represented in the leopard's diet, given the higher densities of goats and cattle. The standing biomass of dogs and cats alone was sufficient to sustain the high density of carnivores at the study site. Our results show that the abundance of potential domestic prey biomass present in human-use areas supports a relatively high density of predators, although this interaction could result in conflict with humans
Urbanization and its Impacts on Land Use, Biodiversity and Ecosystems in India
No full textIndia, a predominantly rural country, is going through a slow but constant and broad transition towards urbanization. The amount of cities and mega cities has increased from 5,161 to 7,935 in 2011. The united Nations predict that, by 2031, 15% of the urban population of the world, about 600 million people, will be living in Indian cities. This increase in urban population will cause repercussions in terms of environment, ecology and sustainability, which will manifest themselves in demands on urban services and governance of the urban ecosystem. In addition, urbanization generates significant tension in terms of land cover, native habitats, biodiversity, protected areas and services to the ecosystem that are basic for human well being. In this paper we analyze some challenges and opportunities for urban development in India that include the participation of governments,
private agencies, ngos, and citizens from different social and economic strata
Inhibition of fungal endophytes by camptothecine produced by their host plant, Nothapodytes nimmoniana (Grahm) Mabb. (Icacinaceae)
Get PDFCamptothecine (CPT), a monoterpene indole alkaloid, is a potent inhibitor of eukaryotic topoisomerase I. It is produced by a number of plants, including Notha-podytes nimmoniana (Grahm) Mabb. (Icacinaceae), occurring naturally in the Western Ghats, India. The plant is inhabited by a number of endophytic fungi, many of which have been isolated and shown to pro-duce CPT, in culture, independent of the host. In this article, we examine the sensitivity of endophytic fungi isolated from N. nimmoniana to CPT. Contrary to our hypothesis that these fungi should be resistant to CPT (as they are exposed to host CPT as well as that pro-duced by themselves), we report that these fungi are sensitive and thus inhibited by CPT. We discuss these results in the context of the role of CPT in limiting endophytic fungal growth
Reshaping Neighborhood Parks for Biodiversity and People: A Case of Unsung Socio-Ecological Systems in Bangalore, India
No full textUrban green spaces have recently gained a lot of attention, as they are known to provide various vital ecosystem services to the community. Bangalore, a
south-Indian city, which was called the “Garden City” of India, has several large green spaces. It is only in recent years that small pocket green spaces such as
neighborhood parks have been created. Although the importance of neighborhood parks is known, they are ignored and readily sacrificed for developmental projects, while the large heritage green spaces receive more attention and are conserved. The concept of the large spaces providing more services seems to have filtered into the minds of citizens, thus resulting in complete negligence towards the neighborhood parks. Cities are required to implement newer concepts which focus on small green spaces too, which could enhance the services they currently provide to the community. Thus integrating multiple concepts that not only focus on the ecological functioning but also the social needs of the community could help increase the stewardship which is currently lacking around neighborhood parks and much
needed attention towards small green spaces. In this chapter, through an interdisciplinary approach, we suggest concepts that could help conserve smaller green
spaces through better green space management in developing citie
Addressing water stress through wastewater reuse: Complexities and challenges in Bangalore, India
Get PDFWastewater reuse is an important adaptation option for mitigating water stress in rapidly growing urban centres. But, wastewater reuse is easier said than done, particularly in developing countries. The task becomes even more challenging when one takes a basin-level perspective. We illustrate these challenges by studying the Vrishabhavathy River in Bangalore, India, which carries almost half of the city’s wastewater. First, we find that the sewage treatment plant (STP) located on this river does not function efficiently and no positive impact of effluent discharge on river water quality was observed. Second, while the Sewerage Board has implem
ented conventional centralized sewage treatment and proposed its expansion and even larger scale projects, decentralized wastewater treatment, advocated by many civil society groups, may be more cost effective. Options at all scales, however, face several institutional
challenges in implementation. Third, while untreated wastewater is a health hazard for downstream farmers using this water for irrigation, substantial wastewater recycling upstream would have a negative impact on their livelihoods by reducing the quantity of water available for irrigation. In addition, as the Vrishabhavathy is a tributary of the inter-state river Cauvery, reduced flows might impact on inter-state water sharing commitments complicating matters further. Realizing the potential of wastewater reuse in Bangalore will thus require techno-institutional integration and thinking at a basin scal
Sikkim’s ecological fragments
Get PDFDuring my first visit to Sikkim in the winter of 2010, I went to a place called Dzongu – a land which is revered and considered sacred by the indigenous Rong, or Lepcha, people. It was dark, and I was outside taking in the fresh, cold mountain air. As I looked around, I could faintly see three lights far apart from each other shining dimly at a much higher elevation. Too distant to be able to make out easily, I asked my host in the village, Lakpa daju (elder brother), a middle-aged man with a default smile and zeal to do something for Dzongu and the Lepcha people, “What are those lights in the darkness on the other side of the hill?” This was my first trip to Dzongu, and I had reached at night. Somehow in the darkness of night, I had the impression that this house was at one extreme of the hill and nothing lay beyond it. Lakpa came out curiously, looked in the direction I was pointing and said, “Oh those? Lights from the houses…” He went in promptly, perhaps because of the biting cold outside