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Camptothecin-producing endophytic bacteria from Pyrenacantha volubilis Hook. (Icacinaceae): A possible role of a plasmid in the production of camptothecin
No full textCamptothecin (CPT), a quinoline alkaloid, is a potent inhibitor of eukaryotic topoisomerase I.
Because of this property, several derivatives of CPT are used as chemotherapeutic agents. CPT is produced by
several plant species belonging to the Asterid clade as well as by a number of endophytic fungal associates of
these plants. In this study, we report the production of CPT by four bacterial endophytes and show the possible
role of a plasmid in the biosynthesis of CPT.
Methods: Endophytic bacteria were isolated from leaves, stems and fruits of Pyrenacantha volubilis Hook.
(Icacinanceae). The bacterial isolates were purified and analyzed for production of CPT by ESI-MS/MS and NMR
analysis. Bacterial identity was established based on the morphology and 16s rRNA sequence analysis. Crude
extracts of the bacterial endophytes were evaluated for their cytotoxicity using colon cancer cell lines. The role
of plasmid in the production of CPT was studied by purging the plasmid, using acriflavine, as well as reconstituting
the bacteria with the plasmid.
Results: Four bacterial isolates, Bacillus sp. (KP125955 and KP125956), Bacillus subtilis (KY741853) and Bacillus
amyloliquefaciens (KY741854) were found to produce CPT in culture. Both based on ESI-MS/MS and NMR
analysis, the identity of CPT was found to be similar to that produced by the host plant. The CPT was biologically
active as evident by its cytotoxicity against colon cancer cell line. The production of CPT by the endophyte
(Bacillus subtilis, KY741853) attenuated with sub-culture. A likely role of a plasmid in the production of CPT was
established. A 5 kbp plasmid was recovered from the bacteria. Bacterial isolate cured of plasmid failed to produce
CPT.
Conclusion: Our study implies a possible role of a plasmid in the production of CPT by the endophytic bacteria
and opens up further work to unravel the exact mechanisms that might be involved
Shrinking harvest: Genetic consequences and challenges for sustainable harvesting of non-timber forest products
Full text linkNon-timber forest products (NTFP) have been an important source of subsistence as well as livelihoods for many forest-dwelling and forest- fringe communities across the developing world. NTFP collection has been promoted as
a win-win strategy to not only conserve biodiversity but also provide livelihood options to scores of forest-dwelling communities. There has been evidence both for, and against, the impacts of harvesting and the ecological
sustainability of harvested species. Harvesting can act as a selective force and reduce the population genetic diversity, especially for species in which the reproductive parts are harvested. A debate has been raging among scientists, resource managers, as well as policy makers for decades, over which methods, and what levels of harvest, can be considered ecologically sustainabl
Impact of institutions on land cover change and landscape fragmentation in an Indian dry tropical forest landscapes
Full text linkProtected Areas (PAs) have been a cornerstone of conservation efforts. However, PAs have become increasingly isolated with protection. Human pressure has shifted towards the forests located outside PAs, which serve as important corridors for wildlife movement. In densely populated countries like India, connectivity across vast landscapes is not possible solely by the
expansion of the PA network and requires support from local communities. The importance of local institutions has been considerably ignored due to the focus on PAs, which have limited capacity to meet local demands as well as conservation objectives for vast landscapes.
This Ph.D. research integrates remote sensing, landscape ecology and institutional approaches to study social and ecological impacts of forest management institutions in a dry-deciduous forest landscape in the Vidarbha region of Maharashtra, India. The study area forms an important
connection between Pench and Tadoba-Andhari Tiger Reserves. The study begins with a largescale landscape view to study the impact of different forest management regimes on forest change and fragmentation. It then zooms in to compare state and community institutions that
differ in traditional norms as well as levels of local participation, assessing their effect on forests and local communities
It’s time to make conservation labour visible again
Full text linkMay Day was not always International Workers’ Day. Before it became International Workers’ Day during the Second Communist International Congress in the 19th century, May Day was a traditional, temperate-region celebration of spring
Rethinking resilience in urbanizing river basins
No full textURBAN resilience is no longer just an idea or a catchphrase. As the concept and practice have evolved, urban resilience now refers not just to the ability
of cities to return to equilibrium after hazard-induced calamities, but also to adapt to and transform in the wake of multiple stressors that cities face, including climate change. Several intervention efforts now focus explicitly on building urban resilience. 100 Resilient Cities, a network of one hundred cities around the world established and supported by the Rockefeller Foundation, is one such initiative of which Bengaluru is a part, along with four other cities in India
Assigning conservation value and identifying hotspots of endemic rattan diversity in the Western Ghats, India
Full text linkRattans, or canes, are one of the most important non-timber forest products supporting the livelihood of many forest-dwelling communities in South and North-eastern India. Due to increased demand for rattan products, rattans have been extracted indiscriminately from the Western Ghats, a 1600-km mountain chain running parallel to the west coast of India. Extensive harvesting, loss of habitat and poor regeneration has resulted in dwindling rattan populations, necessitating an urgent attempt to conserve existing rattan resources. In this study, using niche-modelling tools, an attempt has been made to identify areas of high species richness of rattans in the Western Ghats, one of the mega-diversity regions of the world. We have also developed conservation values for 21 economically important and
endemic rattans of the Western Ghats. We identified at least two to three sites of extremely high species richness outside the existing protected area network that should be prioritized for in situ conservation. This study emphasizes the need to develop strategies for the long-term conservation of rattans in the Western Ghats, Indi
Grain storage losses in the traditional tribal settlements of Biligirirangana Hills, Karnataka, India
No full textThe forest dwelling tribal Soligas who reside at Biligirirangana Hills cultivate more than 30 different crops including pulses, cereals, millets and vegetable crops as a part of subsistence agriculture. They store more than 80% of their produce in their households for consumption. The present study examines the grain storage practices followed by Soligas and the extent of losses incurred by them, in a traditional agricultural setup. In all, 13 different storage structures used by Soligas were recorded. These included both traditional and modern structures. Among these, plastic oven sac was being used most widely, while Thenemane used for storing maize cobs was the least used structure by the Soligas. An evaluation of these storage structures for safe storage of grains revealed that, none of the traditional storage structures were found to be suitable for grain storage, as they had one or the other disadvantages like, not being moisture or insect or rodent proof. However, the modern structures like, the plastic bins were moisture and rodent proof, but they failed to provide protection against insects. Soligas adopted 10 different grain protection methods for safe storage of grains. Despite their use, the presence of insect infestation ranged from 32.14 to 56.41%. Callosobruchus theobromae was the most common stored grain insect found infesting fieldbean (Dolichos bean) that was stored in most of the settlements, while Tribolium castaneum was the rarest, found infesting only split pigeon pea (Cajanus cajana). The extent of grain damage ranged from 10 to 100% in the samples collected
To save an ecology less-explored
Full text linkThe Eastern Ghats are one of the least explored natural landscapes of India. Stretching about 1,750 km north to south, the range begins from central Odisha, continues through Andhra Pradesh and Telangana, before culminating at the Sirumalai hills facing the Western Ghats near Madurai in southern Tamil Nadu
How the decline in India's harrier population hurts its farmers
Full text linkHarriers are a group of birds that belong to the hawk family that are active during the day and mostly found in vast open plains and grasslands. There are 16 species of harriers distributed worldwide throughout tropical and temperate regions, and six of these species migrate to India from central Asia and neighbouring areas during the winter. They can travel between 3,500 km and 5,000 km during this migration. Studies on tagged harriers in Africa show that they follow different routes during spring and autumn migrations. We do not really know much about the migration of harriers from India – the routes they fly from, or their breeding grounds – but researchers once found that a tagged harrier from Gujarat migrated to Kazakhstan
Of Government, God and Gharial: The Ecological Pogrom in Chambal’s Badlands
Full text linkThe highlands of the Vindhyas give birth to one of the most remarkable, yet infamous, of India’s cratonic rivers: the Chambal. Almost 1,000 kilometres long, and bounded by the Aravalli to the north and the Vindhya to the south, the river snakes past the plateaus of Malwa and Hadauti before meeting the Yamuna in the Gangetic plains. Cutting across scarp and shale, several rivers and streams – many of them seasonal – channel into the Chambal, carving their way through the pediplain and a maze of gullies and ravines. Water has been the chief architect of this landscape over millennia and continues to shape the lives of the wonderful creatures here. I’ve spent many a magical minute watching the Chambal flow by, with skimmers gliding over her waters, turtles foraging in the shallows, river dolphins schooling fish, and gharials basking against the stark ravenous backdrop