Botany


https://sites.google.com/a/gauhati.ac.in/research/#ds11092019 Endophytes and plant growth in tomato

https://sites.google.com/a/gauhati.ac.in/research/#ds11092019 Collecting a rare species of flora

https://sites.google.com/a/gauhati.ac.in/research/#ds11092019 Defence mechanism of chickpea pod wall

https://sites.google.com/a/gauhati.ac.in/research/botany/#ds11092019 What's in a drink?

https://sites.google.com/a/gauhati.ac.in/research/#ds11092019 Ovicidal agents for Aedes aegypti

https://sites.google.com/a/gauhati.ac.in/research/#ds11092019 Antibacterial activity of Spotted Gum

https://sites.google.com/a/gauhati.ac.in/research/#ds11092019 Classification of a new plant species

https://sites.google.com/a/gauhati.ac.in/research/#ds11092019 Vermicomposting citronella waste

https://sites.google.com/a/gauhati.ac.in/research/botany/#sb14032019 A new plant species from Assam

https://sites.google.com/a/gauhati.ac.in/research/botany#kt09012019 Isolating antimicrobial compounds

https://sites.google.com/a/gauhati.ac.in/research/botany/#kt21112018 Funiculosone - an antimicrobial metabolites

Endophytes can prevent bacterial wilt disease and promote growth in tomato
Niraj Agarwala and coworkers show how a bacterium isolated from an indigenous plant can help tomato plant growth and prevent infections. This work is reported in Microbiological Research.


Authors
Heena Agarwal, Bhaskar Dowarah, Pooja Moni Baruah, Kuntala Sarma Bordoloi, Debasish B Krishnatreya, and Niraj Agarwala

Abstract
Endophytes are beneficial plant microbes which help the plants by producing various plant growth promoting substances and also by acting as biocontrol agents against various plant pathogens. In the present study, evaluation of endophytic bacteria isolated from Gnetum gnemon, an ethnomedicinal plant was carried out for their plant growth promoting (PGP) activity and antagonistic potential against bacterial wilt pathogen Ralstonia solanacearum. Initially a total of 40 endophytic bacteria were isolated which were clustered into 13 groups based on RFLP and BOX-PCR fingerprinting. These 13 representative isolates belonged to different genera of Bacillus (9), Solibacillus (1), Staphylococcus (2) and Caballeronia (1). Among them, six isolates were positive for production of IAA, the value of which ranged from 11.16 to 27.63 μg mL−1. Phosphate solubilisation in the range of 106.4 to –212.7 μg mL−1 was shown by three isolates. Eight isolates produced ammonia, the value of which ranged from 1.3 to 6.1 μmol mL−1. All tested isolates were positive for siderophore production. For extracellular enzyme production, 7 isolates were positive for protease, 8 for cellulase and 10 for amylase production. The isolates were also tested for their antagonistic activity against R. solanacearum in vitro and in planta assay using tomato seedlings. Staphylococcus warneri GL1 showed the highest biocontrol efficacy of 77.67% followed by Bacillus velezensis GL3 i.e. 70.1%. R. solanacearum antagonistic isolates were analysed for the presence of antimicrobial peptide biosynthesis genes bmyB, srfAA, fenD and ituC. All the antagonistic isolates showed the presence of all four genes, except the isolate Bacillus velezensis GMC2, where the gene for fengycin synthetase (fenD) was absent. Based on in vitro PGP traits, three isolates Bacillus velezensis GL3, Bacillus atrophaeus GMC1 and Bacillus megaterium GS2 were selected, these three endophytic bacteria individually and their consortia were tested for in planta PGP activities in tomato plants. Application of Bacillus velezensis GL3 alone and consortia of three isolates showed significant improvement in growth parameters such as shoot length, fresh weight and dry weight in a pot experiment. Colonisation of endosphere of treated tomato seedlings by the endophytic isolate Bacillus velezensis GL3 was confirmed by visualisation of colony morphology and BOX-PCR fingerprinting. Our study highlights the potential of endophytes associated with unexplored plants like G. gnemon for development of bioformulation aimed at enhancing plant growth and bacterial wilt disease control.

Botany    https://sites.google.com/a/gauhati.ac.in/research/#top 
 



Collecting a rare species of flora
Manash Baruah and collaborators collect an extremely rare plant after about 145 years from a region in the Golaghat district of the northeastern Indian state of Assam. Their findings are reported in the Journal of Threatened Taxa.


Authors
Debolina Dey, Manash Baruah, Nilakshee Devi, and Jitendra Nath Borah1
from another organisation

Abstract
The present work records the re-collection of an extremely rare plant Ceropegia lucida Wall. from the Golaghat District of Assam after a gap of 145 years. A detailed account of the plant has been given to aid in its proper identification and further conservation steps.

Journal Reference


https://sites.google.com/a/gauhati.ac.in/research/#top 
 



Defence mechanism of legumes against herbivorous insects
Pratap Jyoti Handiquea and collaborators examine the defence mechanism of chickpea pod walls against herbivorous insects, using simulated herbivory. This work is published in the journal The Protein Journal.


Authors
Mamta Bhattacharjee1,2, Santanu Dhar1, Pratap Jyoti Handique, Sumita Acharjee1, and Bidyut Kumar Sarmah1
from other institutions

aProf PJ Handique is a Professor in the Department of Biotechnology of Gauhati University, who is also the Vice Chancellor of the university.

Abstract
The pod wall of legumes is known to protect the developing seeds from pests and pathogens. However, the mechanism of conferring defense against insects has not yet been deciphered. Here, the authiors have utilised 2-dimensional gel electrophoresis (2D-GE) coupled with mass spectrometry (MS/MS) to identify over expressed proteins in the pod wall of two different cultivars (commercial cultivar: JG 11 and tolerant cultivar: ICC 506-EB) of chickpea after 12 h of application of Helicoverpa armigera oral secretions (simulated herbivory). The assays were performed with a view that larvae are a voracious feeder and cause substantial damage to the pod within 12 h. A total of 600 reproducible protein spots were detected on gels, and the comparative analysis helped identify 35 (12 up-regulated, 23 down-regulated) and 20 (10 up-regulated, 10 down-regulated) differentially expressed proteins in JG 11 and ICC 506-EB, respectively. Functional classification of protein spots of each cultivar after MS/MS indicated that the differentially expressed proteins were associated with various metabolic activities. Also, stress-related proteins such as mannitol dehydrogenase (MADH), disease resistance-like protein-CSA1, serine/threonine kinase (D6PKL2), endoglucanase-19 etc. were up-regulated due to simulated herbivory. The proteins identified with a possible role in defence were further analysed using the STRING database to advance our knowledge on their interacting partners. It decoded the involvement of several reactive oxygen species (ROS) scavengers and other proteins involved in cell wall reinforcement. The biochemical analysis also confirmed the active role of ROS scavengers during simulated herbivory. Thus, the study provides valuable new insights on chickpea-H.armigera interactions at the protein level.

Journal Reference

Botany    https://sites.google.com/a/gauhati.ac.in/research/#top 
 



What's in a drink?

Hridip Kumar Sarma and his colleagues find out what that makes the indigenous drink that many people from Northeast India relish. This work is published in the Journal of the American Society of Brewing Chemists : The Science of Beer.


Authors
Bhaskar Jyoti Nath1, Ekta Verma3, Hridip Kumar Sarma1, Arun Kumar Mishra3, Bhaben Tanti2, and Dhruva Kumar Jha2

Abstract
In this study, yeasts inherent in traditional starter materials of four indigenous communities from northeast India were characterised. These included Saccharomyces and non-Saccharomyces types representing several genera and species such as Saccharomyces cerevisiae, Wickerhamomyces anomalus, Candida glabrata and Candida tropicalis. The yeasts were cultured in synthetic minimal media (2% glucose and 2% starch), both individually and in combinations. The propensity of growth of individual isolates in glucose appeared as W. anomalus > C. tropicalis > C. glabrata > S. cerevisiae. In starch, the propensity appeared as C. tropicalis > W. anomalus > C. glabrata > S. cerevisiae. The findings were incongruent when isolates were co-cultured in dual combinations in glucose and starch. In glucose, W. anomalus could not prosper with C. tropicalis, which otherwise was reversed in starch. C. tropicalis dominated all the co-cultures in starch followed by W. anomalus, S. cerevisiae and C. glabrata. In glucose, the order appeared as W. anomalus > C. tropicalis > S. cerevisiae > C. glabrata. S. cerevisiae could not thrive in competition with C. tropicalis and appeared dominant over C. glabrata in both glucose and starch. W. anomalus was dominant over S. cerevisiae and C. glabrata, while C. tropicalis outnumbered C. glabrata in both carbon sources. The fermentation efficiency was highest when S. cerevisiae and C. glabrata were co-cultured together, in both starch and glucose. This study suggests an advantage in co-culturing selective indigenous yeasts as consortia to yield a productive fermentation output that could have commercial benefit but additional strains of each species still needed to be investigated.

Journal Reference
Botany     Zoology    https://sites.google.com/a/gauhati.ac.in/research/botany/#top 
 



Essential oils as ovicidal agents for Aedes aegypti (Diptera: Culicidae)

Bulbuli Khanikor and coworkers study the twenty essential plant oils (EO) as potential ovicidal agents for the mosquito species which can spread diseases like dengue fever, chikungunya, Zika, and several others. This work is published in the journal National Academy Science Letters.


Authors
Riju Sarma, Kamal Adhikari, Sudarshana Mahanta, and Bulbuli Khanikor

Abstract
In the present investigation, twenty plant essential oils (EOs) are tested against Aedes aegypti at their egg stage aiming to control the mosquito population at its breeding site. The results are very much promising for EOs extracted from Allium sativum, Mentha piperita and Ocimum sanctum with sublethal concentration (LC50) of 1.00 ppm, 4.01 ppm and 8.40 ppm, respectively, which seems to be at par with WHO-recommended dose for synthetic larvicide temephos. Three plant oils responded with LC50 below 50 ppm. However, few plant oils did not show lethal effects at all. The effective EOs can in future be used in breeding sites including the potable and household water tank as these plants are edible and hence safe for consumption. These might be a potent candidate for decreasing Aedes population and for replacing synthetic insecticides against Aedes. Moreover, these three highly effective EOs would be accessible and cost-effective for common people to use.

Journal Reference
Zoology    https://sites.google.com/a/gauhati.ac.in/research/#top 
 



Antibacterial activity of Spotted Gum (Eucalyptus maculata Hook.) against fish pathogens

Dandadhar Sarma and co-workers investigate the antibacterial properties of leaf essential oil of Sotted Gum against two fish pathogens. This work is published in Journal of Essential Oil Bearing Plants.


Authors
Abhishek Mazumder, Hrishikesh Choudhury, Abhinit Dey, and Dandadhar Sarma

Abstract
The present study was intended to evaluate the antibacterial activity of leaf essential oil (EO) of E. maculata and its major compound, identified from the crude EO against Aeromonas hydrophila and A. jandaei. The major compound was found to be 1,8-cineole through Gas Chromatography-Mass Spectrophotometry-Flame Ionisation Detector analysis. Both EO and 1,8-cineole showed potential antibacterial activity against the tested microorganisms. Sensitivity of A. hydrophila to both crude EO and its major compound was found to be relatively higher, in comparison to A. jandaei. The positive results indicate their efficiency as a natural anti-bacterial agent for the treatment of several pathogenic diseases caused by these two microorganisms, and understanding the relations between traditional cures and current medicines.

Zoology    https://sites.google.com/a/gauhati.ac.in/research/botany/#top 
 



Classification of a new plant species - Impatiens pseudolongipes

Souravjyoti Borah and collaborators report the classification of a new plant species Impatiens pseudolongipes and describe the taxonomic identity of the species Impatiens longipes. This work is reported in the journal Phytotaxa.


Authors
Rajib Gogoi1 , Norbu Sherpa1, and Souravjyoti Borah
from other institution

Abstract
The taxonomic identity of the species Impatiens longipes Hook.f. & Thomson is discussed and a lectotype has been designated for the name. Impatiens pseudolongipes is described and illustrated as a new species.

Impatiens species flowers are complete, bisexual with functional male (androecium) and female (gynoecium) reproductive units, including stamens, carpels and ovary.

Journal References
https://sites.google.com/a/gauhati.ac.in/research/botany/#top 
 



Vermicomposting citronella waste and a mixture of sludge

Hemen Deka and coworkers report about vermicomposting of citronella bagasse and mixture of paper-mill sludge. This work is published in the journal Bioresource Technology.



Authors
T Boruah, A Barman, P Kalita, J Lahkar1, and H Deka
from other institution

Abstract
The vermicomposting potential of Eisenia fetida on citronella bagasse and paper mill sludge mixture was studied. The experiment was carried out in pots by taking a mixture of citronella bagasse and paper mill sludge in 3:2 ratios. The physico-chemical properties such as pH, conductivity, total organic carbon, nitrogen, phosphorus, potassium, calcium, trace elements and heavy metals were studied in the end products. The ash content, humification index, C/N ratio and scanning electron microscopic analysis were done to understand the maturity of the vermicompost. Results revealed that bioconversion of citronella bagasse and paper mill sludge mixture is accompanied with reduction of C/N ratio and humification index; enhancement of nutrients profile, nitrogen fixing, phosphate and potassium solubilising bacterial population. SEM analysis showed that there was more disintegration in vermicompost samples than the initial raw materials and compost. Further, earthworm population and biomass has significantly increased by the end of the experimental trials.

https://sites.google.com/a/gauhati.ac.in/research/botany/#top 
 



Impatiens kamrupana - a new plant species from Assam

Souravjyoti Borah and fellow researchers report about discovery of a new plant species Impatiens kamrupana (Balsaminaceae) from Assam. This is now listed and published in the journal Phytotaxa.


Authors
Souravjyoti Borah, Jatindra Sarma, and Rajib Gogoi

Abstract
Impatiens Kamrupana - a new species is discovered from Kamrup district (rural) of Assam, bordering the adjoining state of Meghalaya. The new species is easily distinguished from its allied taxa by its bicoloured, white and purple flowers and sub-bucciniform lower sepal with straight to slightly curved spur.

Journal Reference
https://sites.google.com/a/gauhati.ac.in/research/botany/#top 
 



Isolating antimicrobial compounds

Kumanand Tayung and fellow researchers have been successful in isolating antimicrobial compound named aspergyllone. This research work is published in Natural Product Research. 



Authors
Srichandan Padhi1, Marco Masi1, Sujogya K Panda1, Walter Luyten1, Alessio Cimmino1, Kumanand Tayung, and Antonio Evidente1
1 from other institutions

Abstract
A new 6-benzyl-γ-pyrone (1), named aspergyllone was isolated from the culture filtrates of an endolichenic fungus Aspergillus niger Tiegh, obtained from lichen thallus Parmotrema ravum (Krog & Swinscow) Serus, collected in India. 1 was isolated for the first time from an endolichenic fungus together with six other known metabolites identified as aurasperones A (2) and D (3), asperpyr- one A (4), fonsecinone A (5), carbonarone A (6) and pyrophen (7). The compounds were tested against a panel of human, plant, food borne and fish pathogens. Aspergyllone showed strong selective antifungal activity against Candida parapsilosis (Ashford) Langeron & Talice, with an IC50 of 52 μg/mL. Aurasperone A and pyrophen showed moderate to strong antimicrobial activity inhibiting seven different test pathogens, being pyrophen active with IC50 ranging from 35 to 97 μg/mL.

Journal Reference
https://sites.google.com/a/gauhati.ac.in/research/botany#top 
 



Funiculosone - a new antimicrobial metabolites

Kumanand Tayung and his collaborators have isolated a new antimicrobial metabolites which also shows anticandidal activity against Candida albicans Berkhout. This research is published in the journal Phytochemistry.



Authors
Srichanadan Padhi1, Marco Masi1, Alessio Cimmino1, Angela Tuzi1, Subhrakanta Jena1, Kumananda Tayung, and Antonio Evidente1
1 from other institutions

Abstract
An undescribed substituted dihydroxanthene-1,9-dione, named funiculosone, was isolated together with its two analogues identified as mangrovamide J and ravenelin, from the culture filtrates of Talaromyces funiculosus (Thom) Samson, Yilmaz, Frisvad & Seifert (Trichocomaceae), an endolichenic fungus isolated from lichen thallus of Diorygma hieroglyphicum (Pers.) Staiger & Kalb (Graphidaceae), in India. Funiculosone was characterised, essentially by spectroscopic methods, as 4,8,9a-trihydroxy-3,4a-dimethyl-4a,9a-dihydro-4H-xanthene-1,9-dione. Its relative stereochemistry was deduced by single crystal X-ray analysis while the absolute configuration was assigned as 4S,4aS,9aS by ECD spectra in comparison to that of the closely related mangrovamide J. This latter, to which, not being an amide, an inappropriate common name was given, was only recently isolated, together with undescribed and known prenylatedindole alkaloids and chromone derivatives from an unidentified Penicillium sp. X-ray structural analysis of the isolated mangrovamide J, for which no biological activity was previously reported, revealed polymorphism and a new crystalline phase is described. All the compounds displayed antibacterial activity with an IC50 range 23–104 μg/mL when assayed against Escherichia coli Escherich and Staphylococcus aureus Ogston. Funiculosone also showed anticandidal activity against Candida albicans Berkhout with an IC50 35 μg/mL.

Journal Reference
https://sites.google.com/a/gauhati.ac.in/research/botany/#top