Physiological conjunction of allelochemicals and desert plants

Plants exchange signals with other physical and biological entities in their habitat, a form of communication termed allelopathy. The underlying principles of allelopathy and secondary-metabolite production are still poorly understood, especially in desert plants. The coordination and role of secondary metabolites were examined as a cause of allelopathy in plants thriving under arid and semiarid soil conditions. Desert plant species, Origanum dayi, Artemisia sieberi and Artemisia judaica from two different sources (cultivar cuttings and wild seeds) were studied in their natural habitats. Growth rate, relative water content, osmotic potential, photochemical efficiency, volatile composition and vital factors of allelopathy were analyzed at regular intervals along four seasons with winter showing optimum soil water content and summer showing water deficit conditions. A comprehensive analysis of the volatile composition of the leaves, ambient air and soil in the biological niche of the plants under study was carried out to determine the effects of soil water conditions and sample plants on the surrounding flora. Significant morpho-physiological changes were observed across the seasons and along different soil water content. Metabolic analysis showed that water deficit was the key for driving selective metabolomic shifts. A. judaica showed the least metabolic shifts, while A. sieberi showed the highest shifts. All the species exhibited high allelopathic effects; A. judaica displayed relatively higher growth-inhibition effects, while O. dayi showed comparatively higher germination-inhibition effects in germination assays. The current study may help in understanding plant behavior, mechanisms underlying secondary-metabolite production in water deficit conditions and metabolite-physiological interrelationship with allelopathy in desert plants, and can help cull economic benefits from the produced volatiles.

Role of brassinosteroids in alleviation of phenanthrene-cadmium co-contamination-induced photosynthetic inhibition and oxidative stress in tomato

Heavy metal pollution often occurs together with organic contaminants. Brassinosteroids (BRs) induce plant tolerance to several abiotic stresses, including phenanthrene (PHE) and cadmium (Cd) stress. However, the role of BRs in PHE+Cd co-contamination-induced stress amelioration is unknown. Here, the interactive effects of PHE, Cd, and 24-epibrassinolide (EBR; a biologically active BR) were investigated in tomato plants. The application of Cd (100 µM) alone was more phytotoxic than PHE applied alone (100 µM); however, their combined application resulted in slightly improved photosynthetic activity and pigment content compared with Cd alone after a 40 d exposure. Accumulation of reactive oxygen species and membrane lipid peroxidation were induced by PHE and/or Cd; however, the differences in effect were insignificant between Cd and PHE+Cd. The foliar application of EBR (0.1 µM) to PHE- and/or Cd-stressed plants alleviated photosynthetic inhibition and oxidative stress by causing enhancement of the activity of the enzymes and related transcript levels of the antioxidant system, secondary metabolism, and the xenobiotic detoxification system. Additionally, PHE and/or Cd residues were significantly decreased in both the leaves and roots after application of EBR, more specifically in PHE+Cd-stressed plants when treated with EBR, indicating a possible improvement in detoxification of these pollutants. The findings thus suggest a potential interaction of EBR and PHE for Cd stress alleviation. These results advocate a positive role for EBR in reducing pollutant residues for food safety and also strengthening phytoremediation.

Benefits of brassinosteroid crosstalk

Brassinosteroids (BRs) are a group of phytohormones that regulate various biological processes in plants. Interactions and crosstalk between BRs and other plant hormones control a broad spectrum of physiological and developmental processes. In this review, we examine recent findings which indicate that BR signaling components mainly interact with the signaling elements of other hormones at the transcriptional level. Our major challenge is to understand how BR signaling independently, or in conjunction with other hormones, controls different BR-regulated activities. The application of a range of biotechnological strategies based on the modulation of BR content and its interplay with other plant growth regulators (PGRs) could provide a unique tool for the genetic improvement of crop productivity in a sustainable manner.

Interaction of brassinosteroids and polyamines enhances copper stress tolerance in raphanus sativus

Brassinosteroids (BRs) and polyamines (PAs) regulate various responses to abiotic stress, but their involvement in the regulation of copper (Cu) homeostasis in plants exposed to toxic levels of Cu is poorly understood. This study provides an analysis of the effects of exogenously applied BRs and PAs on radish (Raphanus sativus) plants exposed to toxic concentrations of Cu. The interaction of 24-epibrassinolide (EBR, an active BR) and spermidine (Spd, an active PA) on gene expression and the physiology of radish plants resulted in enhanced tolerance to Cu stress. Results indicated that the combined application of EBR and Spd modulated the expression of genes encoding PA enzymes and genes that impact the metabolism of indole-3-acetic acid (IAA) and abscisic acid (ABA) resulting in enhanced Cu stress tolerance. Altered expression of genes implicated in Cu homeostasis appeared to be the main effect of EBR and Spd leading to Cu stress alleviation in radish. Ion leakage, in vivo imaging of H(2)O(2), comet assay, and improved tolerance of Cu-sensitive yeast strains provided further evidence for the ability of EBR and Spd to improve Cu tolerance significantly. The study indicates that co-application of EBR and Spd is an effective approach for Cu detoxification and the maintenance of Cu homeostasis in plants. Therefore, the use of these compounds in agricultural production systems should be explored.

Chromium stress mitigation by polyamine-brassinosteroid application involves phytohormonal and physiological strategies in Raphanus sativus L

Brassinosteroids (BRs) and polyamines (PAs) are well-established growth regulators playing key roles in stress management among plants. In the present study, we evaluated the effects of epibrassinolide (EBL, an active BR) and spermidine (Spd, an active PA) on the tolerance of radish to oxidative stress induced by Cr (VI) metal. Our investigation aimed to study the impacts of EBL (10(-9) M) and/or Spd (1 mM) on the biochemical and physiological responses of radish (Raphanus sativus L.) under Cr-stress. Applications of EBL and/or Spd were found to improve growth of Cr-stressed seedlings in terms of root length, shoot length and fresh weight. Our data also indicated that applications of EBL and Spd have significant impacts, particularly when applied together, on the endogenous titers of PAs, free and bound forms of IAA and ABA in seedlings treated with Cr-stress. Additionally, co-applications of EBL and Spd modulated more remarkably the titers of antioxidants (glutathione, ascorbic acid, proline, glycine betaine and total phenol) and activities of antioxidant enzymes (guaicol peroxidase, catalase, superoxide dismutase and glutathione reductase) in Cr-stressed plants than their individual applications. Attenuation of Cr-stress by EBL and/or Spd (more efficient with EBL and Spd combination) was also supported by enhanced values of stress indices, such as phytochelatins, photosynthetic pigments and total soluble sugars, and reduction in malondialdehyde and H(2)O(2) levels in Cr-treated seedlings. Diminution of ROS production and enhanced ROS scavenging capacities were also noted for EBL and/or Spd under Cr-stress. However, no significant reduction in Cr uptake was observed for co-application of EBL and Spd when compared to their individual treatments in Cr-stressed seedlings. Taken together, our results demonstrate that co-applications of EBL and Spd are more effective than their independent treatments in lowering the Cr-induced oxidative stress in radish, leading to improved growth of radish seedlings under Cr-stress.

Phytosterols: perspectives in human nutrition and clinical therapy

Phytosterols (PSs) are a group of plant derived steroid alcohols, with wide occurrence in vegetables and fruits. They are integral components of plant cell membranes, having stabilizing effects on phospholipids bilayer, just like cholesterol in animal cell membranes. Structural resemblance of PSs with cholesterol enables them to displace low-density lipoprotein (LDL) cholesterol in the human intestine. Protective effects of PSs against cardiovascular diseases (CVDs), colon and breast cancer developments have been widely documented. Several reports have been published on the potential dietary intake of common PSs, such as β-sitosterol, stigmasterol and campesterol, and their safety concerns. Ability of PSs to reduce cholesterol levels and risks associated with heart problems has made them a class of favorite food supplements. Nowadays functional foods supplemented with PSs have become an alternative and healthy tool to lower LDL-cholesterol levels in a natural way. However, excessive use of PSs has been observed to develop premature coronary artery disease in phytosterolemic patients, high risk of atherosclerotic CVDs, myocardial infarction and even impaired endothelial functions. This manuscript will highlight the recent developments in PSs with particular focus on their role as dietary supplements and in treatment of various heart- and cholesterol-related ailments. Recently explored side effects of PSs will also be discussed.

Epibrassinolide ameliorates Cr (VI) stress via influencing the levels of indole-3-acetic acid, abscisic acid, polyamines and antioxidant system of radish seedlings

The present investigation determined the effects of epibrassinolide (EBL) on the levels of indole-3-acetic acid (IAA), abscisic acid (ABA), and polyamine (PA) and antioxidant potential of 7-d old Raphanus sativus L. cv. 'Pusa chetki' seedlings grown under Cr (VI) metal stress. Reduced titers of free (0.767 μg g(-1) FW) and bound (0.545 μg g(-1) FW) IAA in Cr (VI) stressed seedlings were observed over untreated control. Supplementations of EBL to Cr (VI) stressed seedlings were able to enhance both free (2.14-5.68 μg g(-1) FW) and bound IAA (2.45-7.78 μg g(-1) FW) concentrations in comparison to Cr (VI) metal treatment alone. Significant rise in free (13.49 μg g(-1) FW) and bound (12.17 μg g(-1) FW) ABA contents were noticed for Cr (VI) stressed seedlings when compared to untreated control. No significant increase in ABA contents were recorded for Cr (VI) stressed seedlings upon supplementation with EBL over Cr (VI) treatment alone. A significant increase in Put (18.40 μg g(-1) FW) and Cad (9.08 μg g(-1) FW) contents were found for 10(-9)M EBL plus Cr (VI) metal treatments when compared to Cr (VI) treatment alone. Spermidine (Spd) contents were found to decline significantly for EBL treatment alone or when supplemented with Cr (VI) treatments over untreated controls and Cr (VI) treatment alone. Antioxidant levels were found to enhance, with glutathione (57.98 mg g(-1) FW), proline (4.97 mg g(-1) FW), glycinebetaine (39.01 μmol mL(-1)), ascorbic acid (3.17 mg g(-1) FW) and phytochelatins (65.69 μmol g(-1) FW) contents noted for EBL supplemented to Cr (VI) metal solution over Cr (VI) treatment alone. Reduced activities of guaiacol peroxidase (0.391 U mg(-1) protein) and catalase (0.221 U mg(-1) protein) and enhanced activities of glutathione reductase (7.14 U mg(-1) protein), superoxide dismutase (15.20 U mg(-1) protein) and ascorbate peroxidase (4.31 U mg(-1) protein) were observed in seedlings treated with EBL plus Cr (VI) over Cr metal treatment alone. Reduced MDA (2.55 μmol g(-1) FW) and H(2)O(2) (33.24 μmol g(-1) FW) contents were recorded for 10(-9)M EBL supplemented to Cr (VI) stress over Cr (VI) treatment alone. Enhancement in free radical scavenging potential as indicated by higher values of 1,1-diphenylpicrylhydrazyl, deoxyribose and reducing power activity assays, and increased levels of phenols and soluble sugars also showed significant influence of EBL in alleviating Cr (VI) stress in radish seedlings.

Epibrassinolide induces changes in indole-3-acetic acid, abscisic acid and polyamine concentrations and enhances antioxidant potential of radish seedlings under copper stress

In the present study, the effects of epibrassinolide (EBL) on indole-3-acetic acid (IAA), abscisic acid (ABA) and polyamine (PA) tissue concentrations and antioxidant potential of 7-day-old Raphanus sativus L. cv. 'Pusa chetki' seedlings grown under Cu stress were investigated. EBL treatment alone or in combination with Cu enhanced free and bound IAA titers when compared with the metal alone. Modest increases in free and bound ABA contents were observed for EBL treatment alone. However, the combination of EBL with Cu caused major increases in both forms of ABA, over Cu alone. Among the PAs analyzed, only putrescine and cadaverine concentrations were enhanced by EBL treatment alone. By contrast, a significant decline in putrescine and spermine contents was found in seedlings treated with EBL plus Cu. EBL treatments alone or in combination with Cu enhanced activities of guaiacol peroxidase (EC1.11.1.7), catalase (EC 1.11.1.6), superoxide dismutase (EC 1.15.1.1) and glutathione reductase (EC 1.6.4.2) and protein contents in comparison with metal and control treatments. A major decrease in malondialdehyde content was also recorded for EBL treatments with or without Cu. An increase in phytochelatin content was also observed in seedlings treated with EBL alone or in combination with Cu. Major improvement in radical scavenging activities, as attested by the antioxidant activity assay using DPPH (1,1-diphenylpicrylhydrazyl), and elevated deoxyribose and reducing powers, along with increased contents of ascorbic acid, total phenols and proline, also suggest a major influence of EBL application in mitigating copper-induced oxidative stress in radish seedlings.

Changing antibiotic sensitivity in enteric fever

Emergence of drug resistance in enteric fever is a major concern for the clinician. All children hospitalized with enteric fever during the period 1 March to 31 May 2000 were studied prospectively for their clinical presentation and response to therapy, and an attempt was made to compare these results with the results of hospitalized children with enteric fever during a similar period in the years 1990 and 1995. The results revealed that there was a significant change in the response to antibiotic therapy as evidenced by significant resistance to ciprofloxacin (55.5 per cent) and early evidence of emerging drug resistance to ceftriaxone (4.4 per cent). Although the sample size was small and had its limitations, the results also pointed towards the re-emergence of sensitivity to chloramphenicol.

Knowledge, attitude and practices about neonatal hypothermia among medical and paramedical staff

The present study was undertaken to evaluate the knowledge, attitude and practices about neonatal hypothermia among medical and paramedical staff dealing with newborn care. A total of 160 subjects were assessed (40 pediatric medicine residents, 40 obstetric residents, 40 private practitioners and 40 paramedical staff working in labor room and postnatal wards) A pre-tested structured questionnaire was used. Only 47.8% of the subjects defined neonatal hypothermia correctly. As many as 52.2% of the interviewees considered it to be an uncommon problem. Lethargy, refusal for feed and cold to touch were mentioned as common symptoms of neonatal hypothermia by 97.5%, 80% and 77.5% of the respondents respectively. Decreased body temperature, cyanosis, apnea and edema of feet were found as common signs. Only 18.6% of the interviewees had knowledge about correct method of recording the temperature in a newborn. The present study reveals the gross lacunae in the knowledge regarding various aspects of neonatal hypothermia among pediatric and obstetric residents and paramedical staff working in labor room and postnatal wards. To reduce the neonatal morbidity and mortality due to neonatal hypothermia, greater emphasis should be laid on this problem while designing curriculum for training of undergraduate and postgraduate doctors, paramedical staff and traditional birth attendants.

Kinetics of interferon-gamma production and its comparison with anti-listeriolysin O detection in experimental bovine listeriosis

The kinetics of the production of interferon gamma (IFN-gamma) in whole blood culture and its comparison with anti-listeriolysin O (ALLO) detection by ELISA were studied during oral infection of calves with Listeria monocytogenes. Culture filtrate antigen (CFA), listeriolysin O (LLO), and sonicated antigen (SA) were used to prime the peripheral blood mononuclear cells (PBMCs) and the plasma from orally infected calves. IFN-gamma and ALLO appeared as early as day 7 of an oral infection. IFN-gamma was detected earlier with LLO than with SA. The Max50 interleukin (IL-2) activity and IFN-gamma estimated in the culture supernatant from PBMCs primed in vitro with different antigens of L. monocytogenes revealed high induction of IL-2 and IFN-gamma by CFA, LLO and live antigen. IFN-gamma assay and ALLO detection were used for testing cases of repeat breeding in dairy cattle. It appeared that detection of IFN-gamma employing LLO can be used to diagnose listerial infections.

Pseudomonas aeruginosa infection-evidences of amphixenosis

In the present investigation many of the isolates of Pseudomonas aeruginosa from human beings, poultry and pigs fell in the same aeruginocine type. Aeruginocine A1 of Ps. aeruginosa was isolated from pigs and also from one of the pig attendants on the farm. Majority of the strains of Ps. aeruginosa of the same aeruginocine type also exhibited similar drug sensitivity patterns. The organism appeared to be polyphagous in nature and infection with this agent may be considered as amphixenosis.

Serological evidence of persistence of Japanese encephalitis virus activity in Bihar, India

A total of 64 sera samples from ducks, 212 from 245 fowls, 1 from 16 sparrows and 5 from human were examined for HI and CF antibodies to Japanese encephalitis (JE), West Nile (NW), Dengue-2 (DN-2), and Chikungunya (CHIK) viruses. The results were compared with those obtained earlier while examining pigs' sera from the same area. The results revealed that ducks, fowls and peridomestic sparrows possessed antibodies to JEV. JEV activity in ducks and fowls was significantly higher compared to its activity in pigs in the same area reported earlier indicating persistence of its activity.

Serological evidence of Japanese encephalitis virus activity in Bihar

Serum samples from 404 pigs originating from eight districts of Bihar were examined for haemagglutination-inhibiting and complement fixing antibodies of Japanese Encephalitis, Dengue-2, West Nile and Chikungunya viruses. Japanese Encephalitis viral infection was found to be widely prevalent compared to other arboviruses tested. RElatively large number of pigs had antibodies to JEV only (i.e. monoconverters). High geometric mean titre to JEV was observed. These observations appear to be of epidemiologic significance to the 1978 epidemic of encephalitis in Bihar. Epidemic of encephalitis was reported in 1978 from several states of India including Bihar. The only evidence of the activity of Japanese Encephalitis in Bihar came from Khan and Banerjee who found neutralizing antibodies in ardeid birds from Asansol - Dhanbad regions. Evidences are presented in this paper on the prevalence of Japanese Encephalitis in eight districts including Dhanbad of Bihar.