The extent of genetic diversity among Vanilla species: Comparative results for RAPD and ISSR     

Praveen C. Verma  Debasis Chakrabarty  Satya Narayan Jena  Devesh K. Mishra  Pradhyumna K. Singh  Samir V. Sawant  Rakesh Tuli 《Industrial Crops and Products》2009,29(2-3):581-589

Vanilla is a large genus of about 110 species in the orchid family (Orchidaceae), including the species Vanilla planifolia from which commercial vanilla flavoring is derived. Since most species of vanilla are considered rare and endangered there is an urgent need to conserve them through genetic analysis and propagation/conservation studies on this crop.The present study investigated the genetic diversity among nine leafy- and leaf-less Vanilla species employing 30 decamer RAPD primers and 10 ISSR primers. The species under study were diverse and displayed a range of variability (0–66% and 0–81% for RAPD and ISSR, respectively). A total of 154 RAPD polymorphic markers (83.24%, h = 0.378) and 93 ISSR polymorphic markers (86.11%, h = 0.363) were used to generate a genetic similarity matrix followed by the cluster analysis. Specific groupings were revealed by each cluster analysis with slight variation between two different markers. Among the nine species studied, V. planifolia, Vanilla aphylla and Vanilla tahitensis revealed very low level of variation within their collections, thus indicating a narrow genetic base. The large genetic distance of Vanilla andamanica from other species suggests its different origin. A close genetic affinity was observed between the pairs V. planifolia, V. tahitensis and Vanilla albida, V. aphylla. These are the first comparative results for RAPD and ISSR reporting inter-relationship among nine cultivated, wild and hybrid Vanilla species.  相似文献   

Feeding Frequency Affects Growth, Not Fillet Composition, of Juvenile Sunshine Bass Morone chrysops×M. saxatilis Grown in Cages     

Carl D.  Webster  Kenneth R.  Thompson  Ann M.  Morgan  Ebony J.  Grisby Siddhartha  Dasgupta 《Journal of the World Aquaculture Society》2001,32(1):79-88

Abstract.— In an effort to feed sunshine bass Morone chrysops × M. saxatilis efficiently, promote optimal growth, and reduce labor costs associated with feeding, sunshine bass were grown in cages and fed one of four feeding frequencies: once/d, twice/d, once every other day (I X/EOD), and twice every other day (2X/EOD) for 21 wk. Juvenile sunshine bass were fed a commercial floating diet containing 40% protein and 11.5% lipid. One hundred fish were hand-counted and stocked into each of 12 3.5-m³ cages with three replications per treatment. At the conclusion of the study, percentage weight gain of sunshine bass fed twice/d was significantly (P < 0.05) higher (1,850%) compared to fish fed all other feeding frequencies. Specific growth rate (SGR) of fish fed twice/d was significantly higher (2.1%/d) compared to fish fed all other feeding regimes, while fish fed once/d had a higher SGR (2.0%/d) compared to fish fed I X/EOD (1.6%/d) and 2X/EOD (1.8%/d). Percentage survival was not significantly different (P > 0.05) among all treatments and averaged 70.4%r. Feed conversion ratio (FCR) of fish fed twice/d was significantly higher (2.40) compared to fish fed all other feeding regimes. Percentage fillet weight of fish fed twice/d was significantly higher (27.8%) compared to all other treatments. Percentage moisture, protein, lipid, and ash in fillet were not significantly different among all treatments and averaged 75.7%, 19.4%, 3.5%, and 1.2%n, respectively (wet-weight basis). Based upon data from the present study, it appears that producers growing juvenile sunshine bass in cages may want to feed fish twice daily. This feeding regimen allows for higher growth rates, without adverse effects on body or fillet compositions. However, economic analysis needs to be conducted to determine if feeding twice/d is profitable.  相似文献   

Saccharum spontaneum: an underutilized tall grass for revegetation and restoration programs     

Vimal Chandra Pandey  Omesh Bajpai  Deep Narayan Pandey  Nandita Singh 《Genetic Resources and Crop Evolution》2015,62(3):443-450

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Chavibetol: major and potent phytotoxin in betel (Piper betle L.) leaf essential oil     

Phirose Kemprai  Pranjit Kumar Bora  Siddhartha Proteem Saikia  Saikat Haldar 《Pest management science》2023,79(11):4451-4462

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Molecular phylogeny in Indian Citrus L. (Rutaceae) inferred through PCR-RFLP and trnL-trnF sequence data of chloroplast DNA     

Satya Narayan Jena  Susheel KumarNarayanan K. Nair 《Scientia Horticulturae》2009

The taxonomy and phylogeny of Indian Citrus is revisited using PCR-RFLP of the trnD-trnT and rbcL-ORF 106 regions as well as sequence data analysis of the trnL-trnF intergenic spacer region of cpDNA. The study was based on 50 accessions of Citrus genotypes, collected from wild, semi-wild and domesticated stocks. Of the 13 restriction enzymes (RE) used for restriction digestion of the polymerase chain reaction (PCR) amplicons, four (Hinf I, Msp I, Alu I, Hae III) generated 47 restriction fragments, of which 24 (51%) were polymorphic. PCR-RFLP data showed a genetic distance ranging from 0 to 0.79 among 50 accessions of Citrus, and a cluster analysis, based on Neighbor-Joining (NJ) method, placed all the accessions in eight major clusters. Analysis of trnL-trnF sequences from 23 representative accessions of Citrus showed a pair-wise sequence divergence rate in the range of 0–0.064. NJ, minimum evolution (ME) and maximum parsimony (MP) analyses of trnL-trnF sequences produced phylogenetic trees, which placed all the 23 accessions in five clusters. PCR-RFLP analysis resulted in a well resolved phylogenetic tree with branches supported by moderate to high bootstrap values, while the trnL-trnF sequence-based trees showed only moderate to low bootstrap support for the internal tree branches, indicating uncertain origin of some Citrus genotypes. This study shows that the trnL-trnF spacer sequence data can detect genetic variation in Indian Citrus genotypes, but the utility of the data in inferring phylogeny at intra and inter-specific levels is limited probably by factors such as hybridization, bud mutations, apomixis and polyploidy. However, PCR-RFLP and trnL-trnF data supported the recognition of C. maxima, C. medica, and C. reticulata as the basal species of edible Citrus.  相似文献   

Biosurfactant-assisted phytoremediation of potentially toxic elements in soil: Green technology for meeting the United Nations Sustainable Development Goals     

Songita SONOWAL  Amy R. NAVA  Sanket J. JOSHI  Siddhartha Narayan BORAH  Nazim F. ISLAM  Soumya PANDIT  Ram PRASAD  Hemen SARMA 《土壤圈》2022,32(1):198-210

Biosurfactants are biomolecules produced by microorganisms, low in toxicity, biodegradable, and relatively easy to synthesize using renewable waste substrates. Biosurfactants are of great importance with a wide and versatile range of applications, including the bioremediation of contaminated sites. Plants may accumulate soil potentially toxic elements(PTEs), and the accumulation efficacy may be further enhanced by the biosurfactants produced by rhizospheric microorganisms. Occasionally, the growth of bacteria slows down in adverse conditions, such as highly contaminated soils with PTEs. In this context,the plant's phytoextraction capacity could be improved by the addition of metal-tolerant bacteria that produce biosurfactants. Several sources, categories,and bioavailability of PTEs in soil are reported in this article, with the focus on the cost-effective and sustainable soil remediation technologies, where biosurfactants are used as a remediation method. How rhizobacterial biosurfactants can improve PTE recovery capabilities of plants is discussed, and the molecular mechanisms in bacterial genomes that support the production of important biosurfactants are listed. The status and cost of commercial biosurfactant production in the international market are also presented.  相似文献   

Growth, Condition, and Size Distribution of Paddlefish, Polyodon spathula, Juveniles Reared in Ponds at Three Densities     

Richard J.  Onders  Steven D.  Mims  Siddhartha  Dasgupta 《Journal of the World Aquaculture Society》2008,39(4):565-571

Abstract.— A study was conducted to determine the effect of increasing density on growth and size distribution of paddlefish, Polyodon spathula, juveniles reared in ponds. Feed‐trained paddlefish of mean weight (±SE) 25.8 ± 1.1 g were randomly stocked into nine 0.02‐ha ponds at 12,355, 18,533, and 24,710 paddlefish/ha, three replications per treatment. The fish were fed daily in excess of what they would eat for 97 d, beginning with a floating trout diet containing 45% protein and 16% lipid and then transferring to a floating catfish diet containing 32% protein and 4.5% lipid. Survival at harvest was not significantly different (P > 0.05) among treatments and averaged 90%. Mean final weights (±SD) for the low‐, middle‐, and high‐density treatments were 205.2 ± 54.1, 174.8 ± 53.2, and 178.6 ± 51.4 g, respectively. Best‐fit distributions centered on these means were lognormal. The low‐density distribution was significantly different (P < 0.05) from the two higher densities, which were not significantly different from each other (P > 0.05). Paddlefish weight at the minimum target length of 35 cm was estimated to be 100 g by regression analysis. The probability of paddlefish reaching or exceeding 100 g was 90% for the low‐density treatment. For the two higher densities, probabilities were 79 and 78%, respectively. Mean Fulton’s condition factors (FCFs) (±SD) were 250 ± 19, 242 ± 4, and 256 ± 37 for the low‐, middle‐, and high‐density treatments, respectively. The FCF for the middle‐density treatment was significantly lower than for the low‐ and high‐density treatments (P < 0.05), which were not significantly different from each other (P > 0.05). CV, feed conversion ratio, and relative growth were not significantly different (P > 0.05) among treatments and averaged 0.43, 1.50, and 5.45, respectively. Monoculture of paddlefish juveniles in ponds results in a hierarchic size structure when density is at least greater than 12,355 paddlefish/ha. The effect is enhanced with increasing density but becomes asymptotic as density approaches 18,533 paddlefish/ha. Feeding in excess does not ameliorate the effect.  相似文献   

Restriction analysis of the mitochondrial DNA of male-sterile and maintainer lines of pearl millet, Pennisetum americanum L.     

S. V. Munjal  R. K. J. Narayan 《Plant Breeding》1995,114(3):256-258

Mitochondrial DNA from two pairs of cytoplasmic male-sterile (cms) and maintainer lines of pearl millet was investigated by restriction-enzyme analysis and Southern-blot hybridization using three mitochondrial gene probes. Each pair of male-sterile and maintainer lines was of a different nuclear origin. The objective was to distinguish differences in the DNA base-sequence organization of the mitochondrial genomes of cms and maintainer lines from the two sources. Restriction-enzyme analysis revealed differences between the different cms and maintainer lines. Southern-blot hybridization experiments using cloned mitochondrial gene probes further distinguished differences between different lines. It is expected that the restriction-fragment-length polymorphisms revealed in the Southern-blot-hybridization experiments will be useful in distinguishing and classifying cms and maintainer lines obtained from different nuclear backgrounds.  相似文献   

Laser annealing of ion-implanted semiconductors     

White CW  Narayan J  Young RT 《Science (New York, N.Y.)》1979,204(4392):461-468

The physical and electrical properties of ion-implanted silicon annealed with high-powered laser radiation are described. Particular emphasis is placed on the comparison of materials properties that can be achieved with laser annealing to those which can be achieved by conventional thermal annealing. Applications of these techniques to the fabrication of high-efficiency solar cells, and potential applications of this new technique to other materials areas are discussed.  相似文献   

Properties of gamma-ray burst progenitor stars     

Kumar P  Narayan R  Johnson JL 《Science (New York, N.Y.)》2008,321(5887):376-379

We determined some basic properties of stars that produce spectacular gamma-ray bursts at the end of their lives. We assumed that accretion of the outer portion of the stellar core by a central black hole fuels the prompt emission and that fall-back and accretion of the stellar envelope later produce the plateau in the x-ray light curve seen in some bursts. Using x-ray data for three bursts, we estimated the radius of the stellar core to be approximately (1 - 3) x 10(10) cm and that of the stellar envelope to be approximately (1 - 2) x 10(11) cm. The density profile in the envelope is fairly shallow, with rho approximately r(-2) (where rho is density and r is distance from the center of the explosion). The rotation speeds of the core and envelope are approximately 0.05 and approximately 0.2 of the local Keplerian speed, respectively.  相似文献