Chemometric Studies of Multielemental Composition of Few Seagrasses from Gulf of Mannar,India

This paper discusses the determination of minerals content (cadmium, cobalt, chromium, copper, nickel, lead, manganese, magnesium, iron, zinc, sodium, potassium and calcium) of six seagrass samples, Enhalus acoroides, Thalassia hemprichii, Halodule pinifolia, Syringodium isoetifolium, Cymodocea serrulata and Cymodocea rotundata using inductively coupled plasma optical emission spectrophotometry and flame photometer. Principal component analysis (PCA) and hierarchical cluster analysis revealed different mineral compositions of the seagrass samples. Among the 13 elements investigated, Ni 1.513, Na 690.167 and Ca 220.333; Cr 3.957; Mn 23.427, Zn 17.593 and Fe 156.567; Cd 0.357, Co 0.431, Pb 2.040, Mg 912.733 and K 300.9; Cu 7.8 mg/kg dry weight, respectively, were found at high concentrations in E. acoroides; T. hemprichii; H. pinifolia; S. isoetifolium and C. rotundata. PCA analysis confirmed the presence of three components with 91.28% of the total variance. The toxic elements Pb, Cr and Cd were also found in all six seagrasses, although the concentrations were below the permissible limits proposed by the World Health Organization.     

Role of Achromobacter xylosoxidans AUM54 in Micropropagation of Endangered Medicinal Plant Naravelia zeylanica (L.) DC

This study was carried out to evaluate the inoculation effects of Achromobacter xylosoxidans AUM54 and Indole-3-butyric acid (IBA) on the growth of the medicinal plant Naravelia zeylanica (L.) DC under micropropagation conditions. Results revealed that the micropropagated shoots treated with the combination of endophytic bacterium and IBA promoted shoot growth, root length, number of roots, chlorophyll content, nitrogen content, antioxidant enzymes, and stress tolerance compared with the control plants. A significant increase in shoot fresh and dry weights (64.65 and 8.85 %), root fresh and dry weights (61.65 and 3.91 %), shoot length (30.17 %), root length (28.57 %) and number of roots (276.9 %) was observed in treated plants over controls. Total chlorophyll and nitrogen content of bacterized plants also treated with IBA showed a 48.39 and 116.66 % increase, respectively, compared with controls. A significant increase in peroxidase (22.52 %) and superoxide dismutase levels (48.38 %) and fewer changes in the polyphenol oxidase level were observed in plants treated with A. xylosoxidans AUM54 and IBA. Moreover, stress ethylene levels were reduced by 21.4 and 14.5 % due to bacterization with A. xylosoxidans AUM54 and IBA treatment during postacclimatization and acclimatization stages, respectively. The shoot primordial with application of A. xylosoxidans AUM54 and IBA (1 mg l^?1) had increased survivability of N. zeylanica plants by 30 % during the acclimatization stage under greenhouse conditions. From the present study it could be inferred that the association of endophytic bacterium A. xylosoxidans AUM54 and IBA with in vitro shoots of N. zeylanica improved root initiation, promoted plant growth and development under micropropagation conditions, reduced stress ethylene levels, and increased survivability during the postacclimatization stage. Therefore, A. xylosoxidans AUM54 along with IBA treatment can be used as a valuable tool for micropropagation of N. zeylanica and other endangered plants.     

High-frequency stable transformation of cotton (Gossypium hirsutum L.) by particle bombardment of embryogenic cell suspension cultures

Stable transformation of cotton (Gossypium hirsutum L.) at a high frequency has been obtained by particle bombardment of embryogenic cell suspension cultures. Transient and stable expression of the β-glucuronidase (GUS) gene was monitored in cell suspension cultures. Transient expression, measured 48 h after bombardment, was abundant, and stable expression was observed in over 4% of the transiently expressing cells. The high efficiency of stable expression is due to the multiple bombardment of rapidly dividing cell suspension cultures and the selection for transformed cells by gradually increasing the concentrations of the antibiotic Geneticin (G418). Southern analysis indicated a minimum transgene copy number of one to four in randomly selected plants. Fertile plants were obtained from transformed cell cultures less than 3 months old. However, transgenic and control plants from cell cultures older than 6 months produced plants with abnormal morphology and a high degree of sterility. Received: 20 January 1999 / Revision received: 1 October 1999 / Accepted: 11 October 1999     

Cotton Biotechnology

Genetically modified (GM) cotton altered for insect and herbicide resistance released into commercial production in 1996 to 1997 now accounts for the lion's share of cotton acreage in the U.S. The rapid increase in transgenic cotton acreage in such a short period of time attests to the overall success of agricultural biotechnology. Grower satisfaction with transgenic cotton is largely due to several significant benefits, such as lower production costs, streamlined yet flexible management, and a reduced impact on the environment. This review article provides an overview of what has been accomplished thus far, as well as what improved germplasm may lurk on the horizon. A critical assessment of the gene delivery systems in cotton and possible targets for improvement is presented. The performance of the first generation of transgenic cotton plants engineered for insect, disease, or herbicide resistance is evaluated from the perspective of the benefits, the limitations that impact field performance, and management strategies. A few traits that hold future promise for increasing fiber productivity, enhancing and/or increasing the novelty of cotton-based products for the consumer, and improving human health and well-being are presented. Above all, cotton biotechnology offers to greatly enhance breeding programs by introducing novel traits that have eluded more traditional plant improvement methods and therefore will likely play an increasingly important role in the genetic improvement of cotton.     

Efficient Record Linkage Algorithms Using Complete Linkage Clustering

Data from different agencies share data of the same individuals. Linking these datasets to identify all the records belonging to the same individuals is a crucial and challenging problem, especially given the large volumes of data. A large number of available algorithms for record linkage are prone to either time inefficiency or low-accuracy in finding matches and non-matches among the records. In this paper we propose efficient as well as reliable sequential and parallel algorithms for the record linkage problem employing hierarchical clustering methods. We employ complete linkage hierarchical clustering algorithms to address this problem. In addition to hierarchical clustering, we also use two other techniques: elimination of duplicate records and blocking. Our algorithms use sorting as a sub-routine to identify identical copies of records. We have tested our algorithms on datasets with millions of synthetic records. Experimental results show that our algorithms achieve nearly 100% accuracy. Parallel implementations achieve almost linear speedups. Time complexities of these algorithms do not exceed those of previous best-known algorithms. Our proposed algorithms outperform previous best-known algorithms in terms of accuracy consuming reasonable run times.