Essential oil from two populations of Echinodorus grandiflorus Micheli. (1/9)

Analysis by Gas Chromatography and Gas Chromatography/Mass Spectrometry of the essential oils obtained from leaves of Echinodorus grandiflorus ("Chapeu de couro") from two different populations (Big Leaves and Small Leaves), collected monthly between September 1998 and December 1999 revealed 17 components. Phytol was the major constituent for both populations. The main sesquiterpene representatives are (E)-caryophyllene, alpha-humulene and (E)-nerolidol.  (+info)

Stability and structure studies on alisol a 24-acetate. (2/9)

Alisol A 24-acetate is one of the main active triterpenoid compounds isolated from Rhizoma Alismatis, which is a famous Traditional Chinese Medicine, and has been determined for the quality control of this crude drug. In this study, alisol A 24-acetate was found to be unstable in solvents and its stability in different solvents was investigated in detail. The results showed that alisol A 24-acetate and 23-acetate inter-transformed in solvents and the transformation rate was more rapid in protic solvents than in aprotic solvents. Moreover, both alisol A 24-acetate and 23-acetate were deacetylated to yield alisol A when kept in methanol for a long time. This is the first report on the structural transformation between alisol A 24-acetate, alisol A 23-acetate and alisol A. In addition, the single crystal X-ray structure of alisol A 24-acetate and the NMR data of alisol A 23-acetate were also reported for the first time.  (+info)

Doassansiopsis caldesiae sp. nov. and Doassansiopsis tomasii: two remarkable smut fungi from Cameroon. (3/9)

Three recent collections of Doassansiopsis from western Cameroon are assessed taxonomically. Doassansiopsis caldesiae M. Piatek & Vanky is described as a new species from infected leaves of Caldesia reniformis (D. Don) Makino. Its diagnostic characters are flat, nonthickened sori with spore balls as blackish, slightly elevated dots, more or less globoid spores, conspicuous cortical sterile cells and parasitism on Caldesia reniformis of family Alismataceae. The species is compared to another Doassansiopsis species on host plants belonging to family Alismataceae. Doassansiopsis tomasii Vanky is described from two localities on Nymphaea nouchali Burm.f. var. caerulea (Savigny) Verdc. (Nymphaeaceae), which represents the first report of this smut from Cameroon and western Africa. Similarities between this species and Doassansiopsis nymphaeae (Syd. & P. Syd.) Thirum. and D. ticonis M. Piepenbr. are outlined and the global distribution of the three taxa is mapped. The species concept in the genus Doassansiopsis is discussed, and a key to all known species of the genus is provided.  (+info)

Field effectiveness of Bacillus thuringiensis israelensis (Bti) against Aedes (Stegomyia) aegypti (Linnaeus) in ornamental ceramic containers with common aquatic plants. (4/9)

This study was undertaken to determine the impact of larvaciding using a Bti (Bacillus thuringiensis israelensis) formulation (VectoBac WG) against Aedes aegypti larvae in earthen jars containing aquatic plants. Aquatic plants commonly used for landscaping, Pistia stratiotes (L.) (Liliopsida: Araceae) and Sagittaria sp. (Liliopsida: Alismataceae) were placed inside earthen jars filled with 50 L tap water. All earthen jars were treated with Bti formulation at 8g/1000L. Untreated jars with and without aquatic plants were also set up as controls. Fifty laboratory-bred 2nd instar larvae were introduced into each earthen jar. All earthen jars were observed daily. Number of adults emerged was recorded and the larval mortality was calculated. The indicators of effectiveness of Bti for these studies were (i) residual activities of Bti, and (ii) larval mortality in earthen jars with or without aquatic plants. The treated earthen jars containing P. stratiotes and Sagittaria sp. showed significant residual larvicidal effect up to 7 weeks, in comparison to untreated control (p < 0.05). The larval mortality ranged from 77.34% - 100% for jars with aquatic plants vs 80.66% - 100% for jars without aquatic plant. Earthen jars treated with Bti without aquatic plants also exhibited significantly longer residual larvicidal activity of up to 10 weeks (p < 0.05). The larval mortality ranged from 12.66% - 100% for jars with aquatic plants vs 59.34% - 100% for jars without aquatic plant. Thus, earthen jars without aquatic plants exhibited longer residual larvicidal effect compared to those with aquatic plants. This study suggested that containers with aquatic plants for landscaping should be treated more frequently with Bti in view of the shortened residual activity.  (+info)

Reproductive toxicity of Echinodorus grandiflorus in pregnant rats. (5/9)

To evaluate the possible toxicity of the aqueous extract of Echinodorus grandiflorus in pregnant rats, animals were distributed in groups treated with 250, 500 and 1,000 mg/kg/day, by gavage, and a control group received saline solution. The treatment was carried out for 15 consecutive days, remaining during mating and until the 14(th) day of gestation. On the 15(th )day, pregnant animals were euthanized by exsanguination under anesthesia. A blood sample was destined to the hematological and biochemical analysis. The ovaries, liver, kidneys, spleen, and adrenal glands were removed and weighed. Liver, kidneys and spleen were processed for histopathological analysis. The number mated, cohabitated and pregnant rats were counted as well as the corpora lutea, implants, resorptions, and live and dead fetuses. Fetus body weight and placenta were measured. Treatment with 1,000 mg of extract caused anemia, leukocytosis, and an increase in AST and in cholesterol. The liver of animals treated with the two higher doses exhibited discrete inflammatory reaction, located mainly at the stroma which supports the portal space; in the kidneys of animals of T-500 and T-1000 groups there was an expressive decrease in the capsular space, and focal areas of vasodilatation and congestion, as well as a discrete hyalinization, and in the spleen of T-1000 group the red pulp presented excessive pigmentation suggestive of hemosiderin. There were no alterations in reproductive parameters, in fetus external morphology or in placenta weight. In conclusion, the extract causes maternal toxicity, though it does not alter the reproductive performance.  (+info)

Do mitochondria play a role in remodelling lace plant leaves during programmed cell death? (6/9)


Structural variations among monocot emergent and amphibious species from lakes of the semi-arid region of Bahia, Brazil. (7/9)


Seagrasses in tropical Australia, productive and abundant for decades decimated overnight. (8/9)

Seagrass ecosystems provide unique coastal habitats critical to the life cycle of many species. Seagrasses are a major store of organic carbon. While seagrasses are globally threatened and in decline, in Cairns Harbour, Queensland, on the tropical east coast of Australia, they have flourished. We assessed seagrass distribution in Cairns Harbour between 1953 and 2012 from historical aerial photographs, Google map satellite images, existing reports and our own surveys of their distribution. Seasonal seagrass physiology was assessed through gross primary production, respiration and photosynthetic characteristics of three seagrass species, Cymodocea serrulata, Thalassia hemprichii and Zostera muelleri. At the higher water temperatures of summer, respiration rates increased in all three species, as did their maximum rates of photosynthesis. All three seagrasses achieved maximum rates of photosynthesis at low tide and when they were exposed. For nearly six decades there was little change in seagrass distribution in Cairns Harbour. This was most likely because the seagrasses were able to achieve sufficient light for growth during intertidal and low tide periods. With historical data of seagrass distribution and measures of species production and respiration, could seagrass survival in a changing climate be predicted? Based on physiology, our results predicted the continued maintenance of the Cairns Harbour seagrasses, although one species was more susceptible to thermal disturbance. However, in 2011 an unforeseen episodic disturbance - Tropical Cyclone Yasi - and associated floods lead to the complete and catastrophic loss of all the seagrasses in Cairns Harbour.  (+info)