Sterol Ring System Oxidation Pattern in Marine Sponges     

Nittala S. Sarma  M. Sri Rama Krishna  S. Ramakrishna Rao 《Marine drugs》2005,3(3):84-111

The marine sponges (Porifera) are a unique group of sedentary organisms from which several novel natural products are reported, many of which have useful biological activities. In producing unusual sterols, they occupy a preeminent position among the various groups of organisms. The polar sterols of sponges reported as at the end of the year 2002 number about 250; their ring structure changing a hundred times. The oxidation pattern in the sterol ring system, from the point of view of biogenesis seems to be mainly of four types. Each sponge species is able to produce sterols fitting into one of the four main biogenetic pathways viz., (i) 3β-hydroxy-Δ⁵-sterol pathway, (ii) 3β-hydroxy-Δ⁷-sterol pathway, (iii) 3β-hydroxy-Δ^5,7-sterol pathway, and (iv) 3α-hydroxy sterol pathway.  相似文献   

Anticarcinogenic effects of curry leaves in dimethylhydrazine-treated rats     

Khanum F  Anilakumar KR  Sudarshana Krishna KR  Viswanathan KR  Santhanam K 《Plant foods for human nutrition (Dordrecht, Netherlands)》2000,55(4):347-355

Curry leaves are one of the spices used in Indian dishes for aroma and preservation. There are no reports on the antioxidant properties of curry leaves. In this study, the antioxidant potential of curry leaves in rats treated with a known chemical carcinogen, dimethylhydrazine hydrochloride (DMH) was investigated. Food intake was reduced in the rats fed curry leaf-supplemented diet but the body and the organ weights were not affected.Vitamin A content in the liver was significantly increased whereas glutathione (GSH) content was not altered. A 50% reduction was seen in the micronuclei induced by DMH and a 30% reduction in the activity of ,-glutamyl transpeptidase when the rats were fed a curry leaf-supplemented diet. These results indicate that curry leaves have highpotential as reducer of the toxicity of DMH.  相似文献   

Enhanced Sequential Flushing Process for Removal of Mixed Contaminants from Soils     

Krishna R. Reddy  Ashraf Z. Al-Hamdan 《Water, air, and soil pollution》2013,224(12):1-13

The feasibility of a sequentially enhanced process for the remediation of soils contaminated by mixed contaminants, specifically multiple polycyclic aromatic hydrocarbons (PAHs) and heavy metals, was investigated. This process consists of sequential flushing using two chemical agents: a surfactant and a chelate. A series of laboratory column experiments was conducted with three different sequential schemes, designated as SEQ1, SEQ2, and SEQ3, in two distinct flushing stages, to remove PAHs and heavy metals from a field-contaminated soil. The SEQ1 scheme involved flushing 0.2 M ethylenediaminetetraacetic acid (EDTA) followed by flushing 5 % Igepal. The SEQ2 scheme involved flushing 5 % Igepal followed by flushing 0.2 M EDTA. SEQ1 was investigated under a constant hydraulic gradient of 1.2, while the SEQ2 scheme was investigated under hydraulic gradients that increased from 1.2 to 4.0. The SEQ3 scheme consisted of sequential flushing of 5 % Igepal (first stage) and 0.2 M EDTA (second stage) under a constant low hydraulic gradient of 0.2. The selected sequential schemes allowed an assessment of the efficacy of sequencing the surfactant and chelating flushing for the removal of multiple heavy metals and PAHs under various hydraulic gradients. The hydraulic conductivity (or flow) was found to vary depending on the flushing agent and the sequence scheme. Under the high hydraulic gradient, the hydraulic conductivity was lower during chelant flushing stage as compared with surfactant flushing stage in both SEQ1 and SEQ2. However, under a low gradient condition (SEQ3), the hydraulic conductivity was approximately the same during both chelant and surfactant flushing stages. The contaminant removal was also significantly affected by the flushing agent and sequence and the applied hydraulic gradient. Heavy metals were removed during chelant flushing, while PAHs were removed during surfactant flushing. The total removal efficiencies of Pb, Zn, and Cu were 76 %, 63 %, and 11 % in SEQ1 and 42 %, 40 %, and 7 % in SEQ2, respectively, while the total removal efficiencies of phenanthrene, anthracene, benz(a)anthracene, and pyrene were 51 %, 35 %, 58 %, and 39 % in SEQ1 and 69 %, 50 %, 65 %, and 69 % in SEQ2, respectively. Overall, the total mass removal of heavy metals and PAHs was higher in SEQ1 as compared with SEQ2, demonstrating that SEQ1 is the effective sequence scheme. Comparison of the results of high and low gradient conditions (SEQ2 and SEQ3) reveals that the removal of contaminants, especially heavy metals, is rate-limited. Overall, this study showed that the removal of co-existing heavy metals and PAHs from soils is possible through the careful selection of the sequence under which the flushing of chelant and surfactant occurs and depends on the site-specific soil and contaminant conditions. Additional research is needed to establish the most optimal flushing scheme (sequence duration and flow velocity) to remove the mixed contaminants effectively and efficiently.  相似文献   

Molecular characterization of a new species of begomovirus associated with yellow vein mosaic of bhendi (Okra) in Bhubhaneswar, India     

V. Venkataravanappa  C. N. Lakshminarayana Reddy  Salil Jalali  M. Krishna Reddy 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(4):811-822

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Integrated management of Meloidogyne incognita‐Fusarium oxysporum f. sp. ciceri wilt disease complex in chickpea     

V. Krishna Rao  K. Krishnappa 《国际虫害防治杂志》2013,59(4):234-237

A field experiment was conducted to study the management of a root‐knot nematode, Meloidogyne incognita (Kofoid and White) Chitw. (Tylenchida: Heteroderidae)‐wilt inducing fungi, Fusarium oxysporum Schlecht. emend. Snyd & Hans. f. sp. ciceri (Padwick) Snyd. & Hans. (Moniliales: Tuberculariaceae) wilt disease complex in chickpea (Cicer arietinum L.). cv. Annegiri. The results indicated that integration of soil solarization (for 6 weeks), VA mycorrhizal fungus (VAM), Glomus fasciculatum inoculation (12g/hill) and seed treatment with carbosulfan (3% w/w) was highly effective in reducing population levels of both pathogens, root‐knotdisease and wilt incidence and in increasing chickpea grain yield significantly. However, seed treatment with carbendazim (0.25% w/w) together with carbosulfan (3% w/w) was not only effective in reducing the wilt disease complex but also economic with an incremental cost: benefit ratio of 1: 2.4.  相似文献   

Anti-Inflammatory Concentrate Enriched with Substituted Oligofucans Derived from Brown Seaweed Turbinaria conoides (J. Agardh) Kützing and Its Safety Assessment on Wistar Rats     

Kajal Chakraborty  Deepu Joseph  Vamshi Krishna Raola 《Journal Of Aquatic Food Product Technology》2013,22(8):1323-1338

ABSTRACT

Aqueous extract of the seaweed Turbinaria conoides was purified to obtain an oligofucan-enriched seaweed concentrate (OESC). Oligofucans isolated were characterized as two types with (→1)-fucose-(2,3-diSO₃^?)-(1→4)-fucose-(2-SO₃^?)-(1→3)-fucose-(2,3-diSO₃^?)-(1→4)-fucose-(2-SO₃^?, 3-OAc)-(4→) and (→1)-fucose-(3-SO₃^?)-(1→4)-fucose-(2-SO₃^?)-(1→4)-fucose-(3-SO₃^?)-(1→4)-fucose-(2-SO₃^?)-(4→) motifs. A 90-day accelerated shelf-life study (50°C) showed that OESC maintained its antioxidant properties (free radical scavenging, reducing, lipid peroxidation inhibition, and chelating activities) even after 30 days. In vitro COX-2 and 5-LOX inhibitory properties of OESC (67.2 and 95.2%, respectively) showed no significant variation even at the 30th day. OESC significantly mitigated the carrageenan-induced inflammation in rats at 0–2 h (59.7–70.3% inhibition), which were greater compared to the synthetic NSAID aspirin. The safety of OESC has been assessed by acute (14 days) and subchronic (90 days) oral toxicity studies, which showed no toxicity-related significant changes in renal or hepatic function, hematological indices, and serum biochemical parameters in the OESC-treated Wistar rats. No histopathological alterations were observed in the vital organs of rats treated with OESC. LD₅₀ and sub-chronic no-observed-adverse-effect level (NOAEL) for this concentrate were found to be > 5,000 and 2,000?mg/kg BW, respectively. Hence, oligofucan-enriched seaweed concentrate is safe to consume without any adverse effects in the body.  相似文献   

Evidence for cross-adaptation between s-triazine herbicides resulting in reduced efficacy under field conditions     

Krutz LJ  Burke IC  Reddy KN  Zablotowicz RM 《Pest management science》2008,64(10):1024-1030

BACKGROUND: Enhanced atrazine degradation has been observed in agricultural soils from around the globe. Soils exhibiting enhanced atrazine degradation may be cross-adapted with other s-triazine herbicides, thereby reducing their control of sensitive weed species. The aims of this study were (1) to determine the field persistence of simazine in atrazine-adapted and non-adapted soils, (2) to compare mineralization of ring-labeled (14)C-simazine and (14)C-atrazine between atrazine-adapted and non-adapted soils and (3) to evaluate prickly sida control with simazine in atrazine-adapted and non-adapted soils.RESULTS: Pooled over two pre-emergent (PRE) application dates, simazine field persistence was 1.4-fold lower in atrazine-adapted than in non-adapted soils. For both simazine and atrazine, the mineralization lag phase was 4.3-fold shorter and the mineralization rate constant was 3.5-fold higher in atrazine-adapted than in non-adapted soils. Collectively, the persistence and mineralization data confirm cross-adaptation between these s-triazine herbicides. In non-adapted soils, simazine PRE at the 15 March and 17 April planting dates reduced prickly sida density at least 5.4-fold compared with the no simazine PRE treatment. Conversely, in atrazine-adapted soils, prickly sida densities were not statistically different between simazine PRE and no simazine PRE at either planting date, thereby indicating reduced simazine efficacy in atrazine-adapted soils.CONCLUSIONS: Results demonstrate the potential for cross-adaptation among s-triazine herbicides and the subsequent reduction in the control of otherwise sensitive weed species. Copyright (c) 2008 Society of Chemical Industry.  相似文献   

Bromoxynil degradation in a Mississippi silt loam soil     

Robert M Zablotowicz  L Jason Krutz  Cesare Accinelli  Krishna N Reddy 《Pest management science》2009,65(6):658-664

BACKGROUND: The objectives of these laboratory experiments were: (1) to assess bromoxynil sorption, mineralization, bound residue formation and extractable residue persistence in a Dundee silt loam collected from 0–2 cm and 2–10 cm depths under continuous conventional tillage and no‐tillage; (2) to assess the effects of autoclaving on bromoxynil mineralization and bound residue formation; (3) to determine the partitioning of non‐extractable residues; and (4) to ascertain the effects of bromoxynil concentration on extractable and bound residues and metabolite formation. RESULTS: Bromoxynil K_d values ranged from 0.7 to 1.4 L kg^?1 and were positively correlated with soil organic carbon. Cumulative mineralization (38.5% ± 1.5), bound residue formation (46.5% ± 0.5) and persistence of extractable residues (T_1/2 < 1 day) in non‐autoclaved soils were independent of tillage and depth. Autoclaving decreased mineralization and bound residue formation 257‐fold and 6.0‐fold respectively. Bromoxynil persistence in soil was rate independent (T_1/2 < 1 day), and the majority of non‐extractable residues (87%) were associated with the humic acid fraction of soil organic matter. CONCLUSIONS: Irrespective of tillage or depth, bromoxynil half‐life in native soil is less than 1 day owing to rapid incorporation of the herbicide into non‐extractable residues. Bound residue formation is governed principally by biochemical metabolite formation and primarily associated with soil humic acids that are moderately bioavailable for mineralization. These data indicate that the risk of off‐site transport of bromoxynil residues is low owing to rapid incorporation into non‐extractable residues. Published 2009 by John Wiley & Sons, Ltd  相似文献   

Association of Pedilanthus leaf curl virus with yellow mottling and leaf curl symptoms in two jasmine species grown in India     

Ashish Srivastava  Susheel Kumar  Shri Krishna Raj 《Journal of General Plant Pathology》2014,80(4):370-373

Association of Pedilanthus leaf curl virus (PeLCV) with yellow mottling of crape jasmine (Tabernaemontana coronaria) and leaf curl of night blooming jasmine (Cestrum nocturnum) was investigated using a sequence analysis of the cloned full-length genome amplified by Rolling circle amplification using Φ-29 DNA polymerase. In the sequence analysis, virus isolates from T. coronaria (JN807764) and C. nocturnum (JQ012790) shared 95 % sequence identity with each other and the highest identity (93 %) and the closest phylogenetic relationships with PeLCV (AM712436); therefore, the virus isolates were identified as PeLCV strains. This report from India is the first on the occurrence of PeLCV on T. coronaria and C. nocturnum anywhere in the world.  相似文献   

印度东北地区一种极频危和特有树种(Ilex khasiana Pork.)再生生态学及种群现状     

Upadhaya Krishna  Barik Saroj Kanta  Adhikari Dibyendu  Baishya Ratul  Lakadong Nigyal John 《林业研究》2009,20(3)

在5个典型自然种群Mylliem(种群1)、Upper Shillong(种群2)、Shillong Peak(种群3)、Laitkor(种群4)和Nongpiyur(种群5)中,详细研究了冬青树(Ilex khasiana)种群结构和再生生态学,旨在探究种群结构和再生能力的影响因素.在全光照(100%),中等光照(50%)和低光照(30%)三种光强度条件下,实验观察表明:在中等和低光照条件下的种苗成活率和生长状态好于在高光照条件下的种苗成活率和生长状态.成年树种群(≥5cm dbh)的密度直径分布揭示了一种再生种群的典型特征.对植被的破坏和人类其他干扰导致森林树冠疏开使光照增强,造成自然种群(L khasiana)幼苗的高死亡率.本研究结果对制定适当的物种保护措施有重要价值.  相似文献