Karrikins are small chemical compounds produced by wildfires. They stimulate germination of dormant seeds present in the soil, so that plant growth is stimulated after the fire. The mechanism of karrikin action has been discovered by research using Arabidopsis thaliana as a model system. This research has identified a gene known as KARRIKIN INSENSITIVE 2 (KAI2) which is required for response to karrikin. The KAI2 protein is present in all plants, including those that do not respond to wildfires or karrikins. Apparently the KAI2 protein is usually involved in perception of a karrikin-like endogenous plant signal. The aim of the research project is to discover this endogenous signal. It will involve the selection of Arabidopsis mutants with phenotypes similar to karrikin insensitive mutants, but which still retain sensitivity to karrikin. These will be putative biosynthesis mutants. It will also involve collaboration with colleagues in chemistry to synthesise and test karrikin analogues for bioactivity, and to search for endogenous plant chemicals with karrikin activity. Experience or knowledge of genetics and biochemistry will be expected for this project. The outcomes will be new skills in plant biochemistry and genetics, and potentially discovery of a new plant signalling molecule.
The current interest of our research group is largely focused on the development and understanding of precipitated crystalline organometallic compounds. We are placing a strong emphasis in the study of the synthetic procedures, the morphology, and on the structural determination of such compounds. Special importance is engaged in the preparation coordination polymers crystallized from solutions of supercritical CO2, (scCO2), where the use of a co-solvent is occasionally employed depending on reagents solubility [1-3]. The correct selection of experimental conditions in the scCO2 reactive crystallization technique, allows a precipitation known from other methodologies, as well as new crystalline phases. This procedure leads to the crystallization of stable hierarchical nanoestructures involving micro and mesoporosity. As the preparation of the crystalline materials is carried out in scCO2, these obtained with microporous structures were recovered activated, i.e., with open volume, since the removal of any guest molecules from the framework is carried out by simple depressurization. This method is expected to have many potential applications in the development of green crystallization techniques for coordination polymers synthesis.
Plants are collected either randomly or by following leads supplied by local healers in geographical areas where the plants are found. Fresh or dried plant materials can be used as a source for the extraction of secondary plant components. Many authors had reported about plant extract preparation from the fresh plant tissues . The logic behind this came from the ethno medicinal use of fresh plant materials among the traditional and tribal people. But as many plants are used in the dry form (or as an aqueous extract) by traditional healers and due to differences in water content within different plant tissues, plants are usually air dried to a constant weight before extraction. Other researchers dry the plants in the oven at about 40˚C for 72 h . In most of the reported works, underground parts (root, tuber, rhizome, bulb etc.) of a plant were used extensively compared with other above ground parts in search for bioactive compounds possessing antimicrobial properties.
Copaiba's traditional uses as an antiseptic for sore throat, upper respiratory and urinary tract infections can be explained partly by the resin's antibacterial properties documented in the 1960s and 1970s. Researchers again confirmed (in 2000 and 2002) that the resin as a whole (and, particularly, two of its diterpenes-copalic acid and kaurenic acid) demonstrated significant antimicrobial activity against gram-positive bacteria. One of copaiba's other chemicals, kaurenoic acid, has also demonstrated selective antibacterial activity against Gram-positive bacteria in other recent studies.
Another recent area of research on copaiba resin has focused on its anticancerous and antitumor properties. Researchers in Tokyo isolated six chemicals (clerodane diterpenes) in the oleoresin of copaiba in 1994 and tested them against carcinomas in mice to determine their antitumor activity. One particular compound, called kolavenol, was twice as effective at increasing the lifespan in mice with carcinomas (by 98%) as the standard chemotherapy drug, 5-Fluorouacil (5-FU). The natural resin also increased lifespan by 82% - which was still higher than 5-FU (which increased lifespan by 46%). Interestingly, the tests provided better anti-tumor effects than in previous test-tube studies. The Spanish team of researchers that documented copaiba's antimicrobial effects in 2002 also tested for antitumor effects. These scientists reported that another phytochemical in the resin, methlyl copalate, had activity against human lung carcinoma, human colon carcinoma, human melanoma, and mouse lymphoid neoplasm cell lines. Brazilian researchers reported in 2002 that one of copaiba's active chemicals, kaurenoic acid, also inhibited the growth of human leukemic cells by 95%, and human breast and colon cancer cells by 45% in vitro. Kaurenoic acid can comprise as much as 1.4% of the natural copaiba oleoresin.
This project explores models for regional strategic thinking by evaluating the existing material and historical conditions of settlements in order to speculate on new futures that address the revival and survival of small towns, regions and landscapes in Tasmania. The objective is to investigate and propose more meaningful understandings of local sites that attract tourists – too often presented as distanced, picturesque and apolitical – as harbouring profoundly sensorial qualities, complex cultural communities and troubled histories as well detrimental effects of human activities on local ecologies. This topical notion of the anthropocene requires we undertake greater immersive and sensory engagement with our local environments: mindful of the part we play within the multiple and fragile ecologies of our lived world: minimizing the binary opposition between nature and culture and acknowledging that local landscapes and their settlements are a fabricated environments and significant public space.
Plants have limitless ability to synthesize aromatic secondary metabolites, most of which are phenols or their oxygen-substituted derivatives. Important subclasses in this group of compounds include phenols, phenolic acids, quinones, flavones, flavonoids, flavonols, tannins and coumarins (). These groups of compounds show antimicrobial effect and serves as plant defense mechanisms against pathogenic microorganisms (). Simple phenols and phenolic acid are bioactive phytochemicals consisting a single substituted phenolic ring. Phenolic toxicity to microorganisms is due to the site(s) and number of hydroxyl groups present in the phenolic compound. Quinones are characteristically highly reactive, colored compounds with two ketone substitutions in aromatic ring. Flavones, flavonoids and flavonols are phenolic structure with one carbonyl group. They are synthesized by plants in response to microbial infection and are often found effective in vitro as antimicrobial substance against a wide array of microorganisms (). Tannins are polymeric phenolic substances possessing the astringent property. These compounds are soluble in water, alcohol and acetone and give precipitates with proteins. Coumarins are phenolic substances made of fused benzene and α-pyrone rings. The crude sap, volatile and essential oil extracted from whole plant or specialised plant parts like roots, stem, leaves, flowers, fruits and seeds are widely used in preparing the antimicrobial compounds which are significantly used against the different plant pathogens/diseases ().
• Active fraction from Ixora coccinea flowers prevented a decrease in body weight, hemoglobin levels and WBC counts of mice treated with cisplastin with significant prolongation of life span of cisplatin-treated mice.
The plant extract showed significant (p)
• Study of an hydroalcoholic leaf extract in ovalalbumin-induced asthmatic rat model showed anti-asthmatic activity suppressing airway inflammation and airway hyperactivity.
The antimicrobial activity was attributed to the presence of active constituents like alkaloids or tannins.
: Study showed intraperitoneal use of Mimosa pudica decoction protected mice against pentylentetrazol and strychnine-induced seizures.
• Plant extracts showed the plant to be a moderate diuretic, depressed duodenal contractions (similar to atropine), promoted nerve regeneration and reduce menorrhagia.
• Also shown to have antidepressant activity.
: Studies on the root extract of M.
Plants contain thousands of constituents and are valuable sources of new and biologically active molecules possessing antimicrobial property (). The ethnobotanical study of plant is important for modern day medicine but its usefulness cannot be overemphasized if methods are not standardized to obtain comparable and reproducible results. At present, scientists are investigating for plant products of antimicrobial properties. It would be advantageous to standardize methods of extraction and in vitro antimicrobial efficacy testing so that the search for new biologically active plant products could be more systematic and interpretation of results would be facilitated. Thousands of phytochemicals which have inhibitory effects on all types of microorganisms in vitro should be subjected in vivo testing to evaluate the efficacy in controlling the incidence of disease in crops, plants, and humans. Efficient collaborations with pharmacologists and medical doctors, plant pathologists and microbiologists are crucial to see the complete development of an interesting lead compound into an exploitable product.