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Search Results: 1 - 10 of 208532 matches for " L Khaleda "
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Genotypic variability in callus induction and plant regeneration through somatic embryogenesis of five deepwater rice (Oryza sativa L.) cultivars of Bangladesh
L Khaleda, M Al-Forkan
African Journal of Biotechnology , 2006,
Abstract: Experiments were carried out to induce embryogenic callus and plant regeneration from five different deepwater rice cultivars. Using mature embryos as explant, all the cultivars demonstrated high callus induction and plant regeneration frequencies. When coleoptile and root segments used as explants, they had low frequencies of embryogenesis. Depending on different genotypes, the best plant regeneration was obtained on LS (Linsmaier and Skoog, 1965) based medium supplemented with 2 mgl-1 BAP + 1.5 mg l-1 2,4-D. Large variabilities in callus growth and plant regeneration potential were revealed among the cultivars tested. Cultivar HA-8 formed a high frequency (78%) of callus than that of other cultivars. In contrast cv. HA-1 produced the highest percentage (72%) of plant regeneration. The callus growth potential was not correlated with the plant regeneration potential. Coleoptiles and root segments produced calli, which did not develop any shoot bud in regeneration media. Moreover, the calli turned blackish, watery and translucent after 25-28 days of culture. It is clear that mature seed scutellum (MSS) is the best explant for callus induction and plant regeneration
Stimulatory Effects of Casein Hydrolysate and Proline in in vitro Callus Induction and Plant Regeneration from Five Deepwater Rice (Oryza sativa L.)
L. Khaleda,M. Al-Forkan
Biotechnology , 2006,
Abstract: Interactive effects of genotypes with callus induction and plant regeneration medium combinations on callus induction and plantlet regeneration response were studied for five deepwater Indica rice cultivars namely; Habiganj Aman-1, Habiganj Aman-2, Habiganj Aman-8, Murabajal and Gheoch. Mature seed scutellums were cultured on MS and LS basal media supplemented with different combinations of 2,4-D, casein hydrolysate (CH) and proline. In cv. HA-8, basal medium combination of MS+2 mg L-1 2,4-D supplemented with 0.6% (w/v) CH was found to be the best for callogenesis where callusing frequency was 87%. The growth rate of callus was frequently increased by the addition of different concentrations of CH with callus induction media. On the other hand, when proline was supplemented in to callus induction media it had no residual effect on callus growth. Embryogenic calli were transferred on MS and LS based regeneration media supplemented with 2 mg L-1 BAP and also different concentrations of casein hydrolysate and proline. The highest regeneration frequency (80%) was observed in cv. HA-1 on LS basal media supplemented with only 2 mg L-1 BAP. However, present study demonstrated that plant regeneration media supplemented with proline is not inhibitory for plant regeneration but have a noticeable comparatively stimulating effect on regeneration from callus. Here combination of casein hydrolysate tremendously reduced plant regeneration. An over all analysis of variations of frequencies for callusing and plant regeneration revealed a contrasting interaction among the culture media and genotypes.
Identification of Callus Induction and Plant Regeneration Responsiveness in Presence of NaCl in in vitro Culture of Some Deepwater Rice (Oryza sativa L.) Cultivars
L. Khaleda,A.M.A. Ahmed,L.W. Marzan,M. Al-Forkan
Asian Journal of Plant Sciences , 2007,
Abstract: The experiment was conducted to identify the in vitro responsiveness for callus induction along with plant regeneration of deepwater rice in the presence of NaCl. In this study, callus induction and plant regeneration responsiveness were tested using different concentrations of 0.1-0.3% (w/v) NaCl which added in MS and LS based media. Marked variation was observed both in calli proliferation and plant regeneration among the six deepwater rice cultivars. In the presence of 0.1% (w/v) NaCl, the highest number of callus induction in all genotypes recorded on the media supplemented with 2 mg L-1 2,4-D + 0.1% (w/v) NaCl. The highest dose of NaCl salt 0.3% (w/v) inhibited callus induction compared to 0.1 and 0.2% NaCl media combinations. Among the cultivars tested, cv. Murabajal produced the highest percentage (39%) of callus whilst cvs. Gheoch (23%) and BR224-2B-2-5 (8%) responded poorly in terms of callus production on the MS based 0.1% NaCl supplemented medium. NaCl had no clear promotive effect on regeneration percentage. In this study, green plant did not regenerate from cv. HA-8. Salinity strongly reduced regenerating capacities of callus obtained from all the cultivars. The mean number of shoots produced per regenerating calli was gradually decreased in all the cultivars when the concentration of NaCl increased in the medium. The apparent tolerance of NaCl in these deepwater rice cultivars may be at least partially related to its growth rate since it can dilute the contents of ion in the shoot. The results of the present study showed the decreasing trend in callus proliferation and plant regeneration with the increasing concentrations of NaCl.
Nd:YAG Laser Posterior Capsulotomy and Visual Outcome
Khaleda Nazneen Bari
Delta Medical College Journal , 2013, DOI: http://dx.doi.org/10.3329/dmcj.v1i1.14971
Abstract: Background: Neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy is a relatively noninvasive procedure that is used in the treatment of posterior capsular opacification (PCO). PCO is caused by proliferation of lens epithelial cells which causes fibrotic changes and wrinkling of the posterior capsule and results in decreased vision, glare, and other symptoms similar to that of the original cataract.Objective: To find out the visual outcome after performing Nd:YAG laser capsulotomy for PCO.Materials and method: A prospective clinical trial was carried out in National Institute of Ophthalmology (NIO), Dhaka, Bangladesh from January 2010 to June 2011 on purposively selected 70 adult subjects of both sexes who developed PCO within 2 months to more than 2 years after extracapsular cataract extraction with posterior chamber intra ocular lens implant. After thorough pre laser assessment Nd:YAG laser capsulotomy was carried out with Zeis VISULAS YAG II through Zeiss slit lamp under topical anesthesia. Data were recorded and expressed as proportion.Results: Out of the 70 subjects 40 were male and 30 were female. The average time interval of cataract surgery and Nd: YAG laser capsulotomy was 23 months. Capsular fibrosis (57.04%) was the predominant type of PCO. The pre laser visual acuity (VA) of more than 61.06% of eyes was 6/36 or below while 41.12% had VA hand movements to finger count. After Nd:YAG laser capsulotomy VA of 6/18 or better was achieved in 63.9% of eyes while 9.94% recovered to 6/9 and 11.36% achieved 6/6. None of these eyes showed further deterioration in VA.Conclusion: Nd:YAG laser capsulotomy for PCO is safe, effective and a rewarding procedure for improvement of vision.
Geographic Concentration and Development Potential of Poultry Microenterprises and Value Chain: A Study Based on Suitable Sites in Gazipur, Bangladesh
Syeda Khaleda,Yuji Murayama
Social Sciences , 2013, DOI: 10.3390/socsci2030147
Abstract: In Bangladesh, many poultry microenterprises (MEs) have flourished through the lending of microcredit to the poor. These MEs are linked to the value chain and play a significant role in poverty reduction. Not all of these MEs are located in favorable places. Almost all are developed utilizing homestead lands, which results in poor input supply and marketing facilities, and causes higher costs and less profit. This paper tries to uncover the constraints in value chain development, mainly those related to its physical and infrastructural environment; verify the potential of MEs through an analysis of their geographic concentration in sites with different suitability levels; and make recommendations as to how to overcome the constraints, with a view to ensuring higher profit levels for vulnerable poor. The suitability of sites was delineated through Geographic Information System (GIS). The analysis—a combination of field survey data with a site suitability map of farms/MEs concentration—is important, because it helps to validate the GIS analysis-based results of sites’ suitability, helps supporters to design interventions in areas where the farms exist, and thus, helps farmers in vulnerable sites to lift themselves out of poverty.
Genetic Divergence, Character Association and Selection Criteria in Irrigated Rice
K. M. Iftekharuddaula,Khaleda Akter,M. S. Hassan,Kaniz Fatema
Journal of Biological Sciences , 2002,
Abstract: Genetic divergence, correlation and path coefficient analysis among 19 genotypes of irrigated rice were studied for grain yield and yield contributing characters. The genotypes under study fell into five clusters. The inter cluster distances were higher than the intra cluster distances indicating wider genetic diversity among the genotypes of different clusters. The intra cluster distances were lower in all the cases reflecting homogeneity of the genotypes within each of the clusters. Regarding inter cluster distance, cluster II showed high genetic distance from all other four clusters. The genotypes from cluster II could be hybridized with the genotypes of any other clusters for producing transgressive segregants. Clustering pattern was not influenced by the geographic origin rather it was influenced by the pedigree of the breeding lines. Harvest index, panicle length and 1000 grain weight showed significant positive correlation with grain yield. Highest direct effect on grain yield was exhibited by spikelets/panicle followed by plant height, harvest index, 1000 grain weight and panicle length respectively. Grains/panicle, spikelets/panicle, flag leaf area, 1000 grain weight and plant height had highest contribution towards divergence respectively. Considering the relative contribution of different characters towards diversity and the effect of correlation and path coefficient all together; the characters like plant height, spiklets/panicle, grains/panicle, 1000 grain weight, flag leaf area and grain yield were found important. Genotypes having these characters of respective cluster would offer a good scope for the improvement of irrigated rice through rational selection.
A Usage Oriented Analysis of Vehicular Networks: from Technologies to Applications
Yacine Khaleda,Manabu Tsukadaa,José Santab,JinHyeock Choia
Journal of Communications , 2009, DOI: 10.4304/jcm.4.5.357-368
Abstract: The research world is paying a lot of attention on vehicular networks nowadays. Novel vehicular services need a suitable communication channel in order to extend in-car capabilities and, generally, be aware about surrounding events. Such networks, however, present some special features, such as high mobility or specific topologies. These properties affect the performance of applications, and more effort should be directed to identify the necessities of the network. Few works deal with application requirements which should be considered when the vehicular network is designed. In this paper, we fill the gap, and propose an analysis of application requirements considering available technologies for the lower and network layer. This study contains key factors which must be taken into account not only at the designing stage of the vehicular services, but also when applications are evaluated.
Genetic Diversity Among Irrigated Traditional and Modern Rice Germplasm
Khaleda Akter,M.K. Bashar,K.M. Iftekharuddaula,M.S. Ahmed
Journal of Biological Sciences , 2002,
Abstract: Forty five rice genotypes originating from Bangladesh, IRRI (Philippines), Japan and China were evaluated under irrigated ecosystem with a view to finding out genetic divergence for 10 characters including yield. The genotypes were constellated into five distinct groups with the range of three genotypes in cluster V and 16 genotypes in cluster III. The inter-cluster distances were larger than the intra-cluster distances in all cases except in cluster III, suggesting wider genetic diversity among the genotypes of different groups. The intra- cluster distance was highest in cluster III and least in cluster V. Maximum inter- cluster distance was observed between genotypes of cluster I and II followed by cluster I and III; II and IV; III and IV and the minimum was found between genotypes of cluster II and III. Plant height, grains/panicle and yield/hill were mainly responsible for genetic divergence while considering mean values. Though grains/panicle, days to flowering and grain length were positive contributors to genetic diversity based on the latent vectors. Clusters with small intra-cluster distances were considered less diverse than those with large distances. The mean yield, grains/panicle, plant height and days to flowering was lowest in cluster I and therefore, crosses involving the genotypes from this cluster with those from cluster II and III may exhibit high heterosis for earliness and grains/panicle. Crosses could also be made between clusters IV with that of II and III for evolving high yielding and early maturing varieties. Closer affinity of Bangladeshi traditional varieties was observed though some of them were in different clusters. Most of the breeding lines were included in cluster III indicating homogeneity in their pedigree.
Genetics of Leaf Water Potential and its Relationship with Drought Avoidance Components in Rice (Oryza sativa L.)
M.K. Bashar,Khaleda Akter,K.M. Iftekharuddaula,M.S. Ali
Journal of Biological Sciences , 2003,
Abstract: Leaf water potential (y leaf) was measured in culture solution in hydroponic system under controlled condition of the two crosses involving diverse rice genotypes to investigate the inheritance pattern and heritability. Polygenes were involved in this trait and theψleaf was governed either by no-dominant or partial dominant alleles and that was controlled by genes with additive effects in upland and hill rice. The heritability estimates were low (25-28%). Leaf water potential was significantly and positively correlated with root thickness, root volume, root length, plant height and leaf area in one of the two crosses. Negative relationship was found with shoot dry weight.
Nanovesicles from Malassezia sympodialis and Host Exosomes Induce Cytokine Responses – Novel Mechanisms for Host-Microbe Interactions in Atopic Eczema
Ulf Gehrmann,Khaleda Rahman Qazi,Catharina Johansson,Kjell Hultenby,Maria Karlsson,Lena Lundeberg,Susanne Gabrielsson,Annika Scheynius
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0021480
Abstract: Intercellular communication can occur via the release of membrane vesicles. Exosomes are nanovesicles released from the endosomal compartment of cells. Depending on their cell of origin and their cargo they can exert different immunoregulatory functions. Recently, fungi were found to produce extracellular vesicles that can influence host-microbe interactions. The yeast Malassezia sympodialis which belongs to our normal cutaneous microbial flora elicits specific IgE- and T-cell reactivity in approximately 50% of adult patients with atopic eczema (AE). Whether exosomes or other vesicles contribute to the inflammation has not yet been investigated.
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