scholarly journals Measurement and Preservation of the in Vivo Activation of Ribulose 1,5-Bisphosphate Carboxylase in Leaf Extracts

1982 ◽  
Vol 69 (5) ◽  
pp. 1165-1168 ◽  
Author(s):  
John T. Perchorowicz ◽  
Deborah A. Raynes ◽  
Richard G. Jensen
Keyword(s):  
Leaf Extracts ◽  
Bisphosphate Carboxylase

scholarly journals Differential Expression of the CO2 Fixation Operons of Rhodobacter sphaeroides by the Prr/Reg Two-Component System during Chemoautotrophic Growth

2002 ◽  
Vol 184 (23) ◽  
pp. 6654-6664 ◽  
Author(s):  
Janet L. Gibson ◽  
James M. Dubbs ◽  
F. Robert Tabita
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Cytochrome Oxidase ◽  
Rhodobacter Sphaeroides ◽  
Rhodobacter Capsulatus ◽  
Response Regulator ◽  
Signal Transduction Pathway ◽  
Pentose Phosphate ◽  
Bisphosphate Carboxylase

ABSTRACT In Rhodobacter sphaeroides, the two cbb operons encoding duplicated Calvin-Benson Bassham (CBB) CO2 fixation reductive pentose phosphate cycle structural genes are differentially controlled. In attempts to define the molecular basis for the differential regulation, the effects of mutations in genes encoding a subunit of Cbb3 cytochrome oxidase, ccoP, and a global response regulator, prrA (regA), were characterized with respect to CO2 fixation (cbb) gene expression by using translational lac fusions to the R. sphaeroides cbb I and cbbII promoters. Inactivation of the ccoP gene resulted in derepression of both promoters during chemoheterotophic growth, where cbb expression is normally repressed; expression was also enhanced over normal levels during phototrophic growth. The prrA mutation effected reduced expression of cbbI and cbbII promoters during chemoheterotrophic growth, whereas intermediate levels of expression were observed in a double ccoP prrA mutant. PrrA and ccoP1 prrA strains cannot grow phototrophically, so it is impossible to examine cbb expression in these backgrounds under this growth mode. In this study, however, we found that PrrA mutants of R. sphaeroides were capable of chemoautotrophic growth, allowing, for the first time, an opportunity to directly examine the requirement of PrrA for cbb gene expression in vivo under growth conditions where the CBB cycle and CO2 fixation are required. Expression from the cbbII promoter was severely reduced in the PrrA mutants during chemoautotrophic growth, whereas cbbI expression was either unaffected or enhanced. Mutations in ccoQ had no effect on expression from either promoter. These observations suggest that the Prr signal transduction pathway is not always directly linked to Cbb3 cytochrome oxidase activity, at least with respect to cbb gene expression. In addition, lac fusions containing various lengths of the cbbI promoter demonstrated distinct sequences involved in positive regulation during photoautotrophic versus chemoautotrophic growth, suggesting that different regulatory proteins may be involved. In Rhodobacter capsulatus, ribulose 1,5-bisphosphate carboxylase-oxygenase (RubisCO) expression was not affected by cco mutations during photoheterotrophic growth, suggesting that differences exist in signal transduction pathways regulating cbb genes in the related organisms.

scholarly journals In vivo antidiarrheal study of ethanolic extracts of Mikania cordata and Litsea monopetala leaves

2015 ◽  
Vol 10 (3) ◽  
pp. 562 ◽  
Author(s):  
Fatema Nasrin ◽  
Md. Lukman Hakim
Keyword(s):  
Body Weight ◽  
Castor Oil ◽  
Leaf Extract ◽  
Positive Control ◽  
Control Group ◽  
P Value ◽  
Leaf Extracts ◽  
Ethanolic Extracts ◽  
Antidiarrheal Activity

<p class="Abstract">In this study the antidiarrheal activity of ethanolic extracts of the leaves of <em>Mikania cordata</em> and <em>Litsea monopetala</em> was evaluated. Diarrhea was induced in mice by oral administration of castor oil (0.5 mL) 30 min after the administration of the extracts. During a 4 hour study the number of diarrheal feces and percentage inhibition of the extracts (200 and 400 mg/kg body weight) was determined. Loperamide (3 mg/kg body weight) served as standard and belonged to the positive control group. The extracts exhibited potent antidiarrheal activity as well as achieved statistically significant p value (p&lt;0.01 and p&lt;0.05) compared to control group. Among the extracts the highest percentage inhibition of defecation (60%) was recorded for leaf extract (400 mg/kg body weight) of <em>L. monopetala</em>. So, the study corroborates the significant antidiarrheal activity of <em>M. cordata</em> and <em>L. monopetala</em> leaf extracts and raises the demand of further sophisticated investigation.</p><p> </p>

scholarly journals LARVICIDAL ACTIVITY OF LANTANA INDICA AND VITEX NEGUNDO ON CULEX QUINQUEFASCIATUS

2018 ◽  
Vol 11 (5) ◽  
pp. 414
Author(s):  
Rathnasagar K ◽  
Thiyagaraj Anand
Keyword(s):  
Larvicidal Activity ◽  
Culex Quinquefasciatus ◽  
Binding Protein ◽  
Inhibitory Effect ◽  
Negative Control ◽  
Vitex Negundo ◽  
Leaf Extracts ◽  
Active Compounds ◽  
Sterol Binding

Objectives: The activity of two different leaf extracts of Lantana indica and Vitex negundo is tested against the 3rd and 4th instar Culex quinquefasciatus larvae to evaluate the potency of the extracts as a larvicide and to find an ecologically sustainable alternative to chemical insecticides. A bioinformatics screening approach was performed to evaluate the in vivo results.Methods: The obtained larvae’s from nearby water sources were tested with N, N-diethyl-meta-toluamide (DEET) as the positive control which is the commercial chemical mosquito repellent and the solvents used for the respective plant extracts act as the negative control. Petroleum ether (PE), ethyl acetate (EA) and an aqueous (AQ) extract were prepared for both L. indica and V. negundo extracts, and its larvicidal activity was tested. A docking based approach was used to study the inhibitory effect of known active compounds from L. indica and V. negundo against acetylcholine esterase (AChE) and sterol binding protein as targets.Results: On comparing the results between three plants extract for its larvicidal activity, the EA extract of V. negundo and L. indica is found to be potent with a low LC50 value. Further, the docking studies between active compounds of L. indica and V. negundo with AChE and Sterol binding protein as targets showed that the compound tangeritin-1 had a good docking score compared to DEET and could be a natural alternative for larvicidal activity in the mosquito.Conclusion: Individual activity of tangeritin-1 could be further studied with mosquito mortality studies and molecular simulations and develop tangeritin-1 as a potential larvicidal compound for commercial use.

In vitro and in vivo activities of Melia azedarach L. aqueous leaf extracts on murine lymphocytes

Phytomedicine ◽  
1998 ◽  
Vol 5 (1) ◽  
pp. 47-53 ◽  
Author(s):  
M.C. Courrèges ◽  
F. Benencia ◽  
F.C. Coulombié ◽  
C.E. Coto
Keyword(s):  
Melia Azedarach ◽  
Leaf Extracts

scholarly journals ANTIMICROBIAL ACTIVITY OF AQUEOUS AND ETHANOLIC LEAF EXTRACTS OF ANACARDIUM OCCIDENTALE

2018 ◽  
Vol 11 (12) ◽  
pp. 474
Author(s):  
Shobha Kl ◽  
Amita Shobha Rao ◽  
Pai Ksr ◽  
Sujatha Bhat
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Klebsiella Pneumoniae ◽  
Bacterial Infections ◽  
Ethanolic Extract ◽  
Culture Collection ◽  
Anacardium Occidentale ◽  
Diffusion Method ◽  
Leaf Extracts

Objective: The objective of this study was to evaluate the antimicrobial activity of leaves of Anacardium occidentale (A. occidentale) against microorganisms including multidrug-resistant (MDR) bacteria. Methods: Agar well diffusion method was employed to demonstrate the antimicrobial activity of leaves A. occidentale. Ethanol and aqueous extracts of the leaves were used against microorganisms, which included American type culture collection strains of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, and Pseudomonas aeruginosa and the clinical isolates of Streptococcus pneumoniae, Candida albicans, MDR Escherichia coli, and MDR Klebsiella pneumoniae. Results: The ethanolic extract of leaves of A. occidentale showed significant antimicrobial activity. Aqueous extract had mild antifungal activity. Conclusion: Ethanolic extract of leaves of A. occidentale could be a good source for the antibacterials to combat MDR bacterial infections. Further studies are necessary for these potent plant extracts to evaluate the in vivo efficacy and toxicity.

scholarly journals Slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity

2017 ◽  
Vol 372 (1730) ◽  
pp. 20160543 ◽  
Author(s):  
Samuel H. Taylor ◽  
Stephen P. Long
Keyword(s):  
Photosynthetic Efficiency ◽  
Green Revolution ◽  
Photosynthetic Electron Transport ◽  
Yield Potential ◽  
Carbon Gain ◽  
Bisphosphate Carboxylase ◽  
Flag Leaves ◽  
Speed Of Adjustment ◽  
Typical Day

Wheat is the second most important direct source of food calories in the world. After considerable improvement during the Green Revolution, increase in genetic yield potential appears to have stalled. Improvement of photosynthetic efficiency now appears a major opportunity in addressing the sustainable yield increases needed to meet future food demand. Effort, however, has focused on increasing efficiency under steady-state conditions. In the field, the light environment at the level of individual leaves is constantly changing. The speed of adjustment of photosynthetic efficiency can have a profound effect on crop carbon gain and yield. Flag leaves of wheat are the major photosynthetic organs supplying the grain of wheat, and will be intermittently shaded throughout a typical day. Here, the speed of adjustment to a shade to sun transition in these leaves was analysed. On transfer to sun conditions, the leaf required about 15 min to regain maximum photosynthetic efficiency. In vivo analysis based on the responses of leaf CO 2 assimilation ( A ) to intercellular CO 2 concentration ( c i ) implied that the major limitation throughout this induction was activation of the primary carboxylase of C3 photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). This was followed in importance by stomata, which accounted for about 20% of the limitation. Except during the first few seconds, photosynthetic electron transport and regeneration of the CO 2 acceptor molecule, ribulose-1,5-bisphosphate (RubP), did not affect the speed of induction. The measured kinetics of Rubisco activation in the sun and de-activation in the shade were predicted from the measurements. These were combined with a canopy ray tracing model that predicted intermittent shading of flag leaves over the course of a June day. This indicated that the slow adjustment in shade to sun transitions could cost 21% of potential assimilation. This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’.

scholarly journals Effects of botanicals against anthracnose and blight diseases of Houttuynia cordata Thunb

2016 ◽  
Vol 42 (1) ◽  
pp. 41-48
Author(s):  
Trisha Saha ◽  
Shamim Shamsi
Keyword(s):  
Azadirachta Indica ◽  
Pathogenic Fungi ◽  
Tagetes Erecta ◽  
Citrus Limon ◽  
Leaf Extracts ◽  
Houttuynia Cordata ◽  
Datura Metel ◽  
Houttuynia Cordata Thunb

Anthracnose and blight were recorded on Houttuynia cordata Thunb. during April 2013 to December 2013. The isolated fungi from the symptomatic plants were identified as Alterneria alternata (Fr.) Keissler and Colletotrichum gloeosporoides (Penz.) Sacc. Ethanol leaf extracts of five plants viz.,Azadirachta indica L., Citrus limon L., Datura metel L., Sennaalata L. and Tagetes erecta L.were evaluated against the pathogenic fungi A. alternata and C. gloeosporoides at 5%, 10% and 20% concentrations in vitro. A. indica recorded as good inhibitor against the test fungi followed by C. limon, S. alata, D. metel and T.erecta. In vivo treatment also showed that A.indica is the most effective in controlling diseases at 10% concentration. The plants treated with A. indica were fresh and healthy up to one month of observation.J. Asiat. Soc. Bangladesh, Sci. 42(1): 41-48, June 2016

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