Identification and systematics of rust fungi in Queensland

Topic: Identification and systematics of rust fungi in Queensland
Supervisors: Tanya Scharaschkin (NRS), Roger Shivas (QDPI&F), Andrew Geering (QDPI&F)
If interested, contact: Dr Tanya Scharaschkin, School of Natural Resource Sciences. Email – t.scharaschkin@qut.edu.au
Duration: Mid November 2008 to mid February 2009 (start and end dates are flexible)
Description:
The rust fungi (Uredinales) are destructive pathogens of a range of plants including cereals, legumes, forest trees and native plants. They have caused famines and destroyed the economies of entire countries. Rusts usually attack the leaves of plants where they can produce up to five different types of spores. Most rusts are limited to specific host plant families, genera or even species.
There are approximately 7,000 species of rust fungi worldwide, with over 500 species reported from Australia. The QDPI&F Plant Pathology Herbarium (Indooroopilly) has a large collection of specimens of rust fungi from Australia. Amongst these specimens are many unidentified and undescribed species of rust fungi, particularly those found on native Australian plants.
Traditional taxonomy of the rusts has been based primarily on the morphology of teliospores. An opportunity exists for a student to work with this collection under the supervision of experienced mycologists and molecular biologists. The student will use morphological and molecular techniques to gain an understanding of the diversity and phylogeny of rust fungi in Queensland. This project has potential to result in publications (e.g., description of new species) and could be extended into an honours research project.

DNA replication cycle in parthenogenetically developing eggs of the starfish Asterina pectinifera

DNA replication cycle in parthenogenetically developing eggs of the starfish Asterina pectinifera

Author(s): Nomura A, Nemoto S
Source: DEVELOPMENT GROWTH & DIFFERENTIATION Volume: 40 Issue: 4 Pages: 377-386 Published: AUG 1998
Times Cited: 4 References: 16 Citation Map
Abstract: Starfish oocytes artificially activated by a calcium ionophore will develop normally if the formation of polar bodies is suppressed. In the present paper, schedules of the DNA replication period (S phase) of these parthenogenotes were explicitly timed using 5-bromo-2'-deoxyuridine (BrdU) and anti-BrdU monoclonal antibody. Their schedule of S phase was identical to that of fertilized eggs. Consequently an S phase regulation system is triggered even in parthenogenotes raised by dual treatment of egg activation and polar body suppression. The S phase schedule of parthenogenotes confirms the temporal pattern of chromosome duplication, observed by other researchers, leading to tetraploid parthenogenotes. The S phase determination also provides a basis for argument concerning the number of centrioles participating in parthenogenetic development. If polar body formation of activated eggs was not suppressed, the first S phase was normal, but the second S phase did not recur on time. A rigidly regulated system of DNA replication cycle, which should be an essential prerequisite for parthenogenesis, thus requires the content of polar bodies.

Biology of Wolbachia

Biology of Wolbachia
Author(s): Werren JH
Source: ANNUAL REVIEW OF ENTOMOLOGY Volume: 42 Pages: 587-609 Published: 1997
Times Cited: 414 References: 132 Citation Map
Abstract: Wolbachia are a common and widespread group of bacteria found in reproductive tissues of arthropods. These bacteria are transmitted through the cytoplasm of eggs and have evolved various mechanisms for manipulating reproduction of their hosts, including induction of reproductive incompatibility, pathenogenesis, and feminization. Wolbachia are also transmitted horizontally between arthropod species. Significant recent advances have been made in the study of these interesting microorganisms. In this paper, Wolbachia biology is reviewed, including their phylogeny and distribution, mechanisms of action, population biology and evolution, and biological control implications. Potential directions for future research are also discussed.

Chronic pubertal, but not adult chronic cannabinoid treatment impairs sensorimotor gating, recognition memory, and the performance in a progressive ra

Chronic pubertal, but not adult chronic cannabinoid treatment impairs sensorimotor gating, recognition memory, and the performance in a progressive ratio task in adult rats

Source: NEUROPSYCHOPHARMACOLOGY Volume: 28 Issue: 10 Pages: 1760-1769 Published: OCT 2003

Abstract: There is evidence from studies in humans and animals that a vulnerable period for chronic cannabinoid administration exists during certain phases of development. The present study tested the hypothesis that long-lasting interference of cannabinoids with the developing endogenous cannabinoid system during puberty causes persistent behavioral alterations in adult rats. Chronic treatment with the synthetic cannabinoid agonist WIN 55,212-2 (WIN) (1.2 mg/kg) or vehicle was extended over 25 days either throughout the rats' puberty or for a similar time period in adult rats. The rats received 20 injections intraperitoneally (i.p.), which were not delivered regularly. Adult rats were tested for object recognition memory, performance in a progressive ratio (PR) operant behavior task, locomotor activity, and prepulse inhibition (PPI) of the acoustic startle response (ASR). PPI was significantly disrupted only by chronic peripubertal cannabinoid treatment. This long-lasting PPI deficit was reversed by the acute administration of the dopamine antagonist haloperidol. Furthermore, we found deficits in recognition memory of pubertal-treated rats and these animals showed lower break points in a PR schedule, whereas food preference and locomotion were not affected. Adult chronic cannabinoid treatment had no effect on the behaviors tested. Therefore, we conclude that puberty in rats is a vulnerable period with respect to the adverse effects of cannabinoid treatment. Since PPI deficits, object recognition memory impairments, and anhedonia/avolition are among the endophenotypes of schizophrenia, we propose chronic cannabinoid administration during pubertal development as an animal model for some aspects of the etiology of schizophrenia.
Document Type: Article
Language: English
Author Keywords: WIN 55,212-2; recognition memory; prepulse inhibition; reward; schizophrenia; puberty
KeyWords Plus: SPATIAL WORKING-MEMORY; OBJECT-RECOGNITION; PREFRONTAL CORTEX; PREPULSE INHIBITION; DOPAMINE NEURONS; CHRONIC DELTA(9)-TETRAHYDROCANNABINOL; SCHIZOPHRENIC-PATIENTS; RECEPTOR ANTAGONIST; ACOUSTIC STARTLE; BRAIN
Reprint Address: Schneider, M (reprint author), Univ Bremen, Dept Neuropharmacol, Brain Res Inst, POB 33 04 40, D-28334 Bremen, Germany
Addresses:
1. Univ Bremen, Dept Neuropharmacol, Brain Res Inst, D-28334 Bremen, Germany
Publisher: NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
Subject Category: Neurosciences; Pharmacology & Pharmacy; Psychiatry
IDS Number: 729XG
ISSN: 0893-133X
DOI: 10.1038/sj.npp.1300225

MARIJUANA AND REPRODUCTION - EFFECTS ON PUBERTY AND PREGNANCY IN FEMALE RATS - EXPERIMENTAL RESULTS

MARIJUANA AND REPRODUCTION - EFFECTS ON PUBERTY AND PREGNANCY IN FEMALE RATS - EXPERIMENTAL RESULTS

Source: ANNALES D ENDOCRINOLOGIE Volume: 53 Issue: 1 Pages: 37-43 Published: 1992

Abstract: The main psychoactive component of marihuana, delta-9-tetrahydrocannabiol (THC), was investigated at low doses (1-mu-g/kg/day) on the onset of puberty, on the reproductive functions in female rats up to the seventy fifth to eightieth day of life as well as during the pregnancy.
The administration of THC caused a delay of the onset of puberty, and the number of ova on the day of first estrus was significantly lower in treated animals.

After puberty, alterations occured in the neuroendocrine functions of animals received THC: estrous cycles were irregular, serum LH level was decreased.

When THC was injected during the third week of pregnancy it caused a significant prolongation of the gestation period. There was 30 % stillbirths (v.s. 3 % in physiological saline treated rats). No teratological effects were observed. Serum LH, progesterone and prostaglandin contents were decreased.

The results indicate that marihuana causes alterations in reproductive functions. The importance of fight against drug abuse is emphasized.

Document Type: Article
Language: French
KeyWords Plus: DELTA-9 TETRAHYDRO-CANNABINOL; ADULT MALE-RATS; LUTEINIZING-HORMONE; SERUM LH; DELTA-9-TETRAHYDROCANNABINOL; ENDOCRINE; EXPOSURE; ALCOHOL; FSH
Reprint Address: WENGER, T (reprint author), FAC MED BUDAPEST, ANAT LAB 2, BUDAPEST, HUNGARY
Addresses:
1. FAC MED LILLE, HISTOL EMBRYOL & BIOL REPROD LAB, F-59045 LILLE, FRANCE
2. UNIV BORDEAUX 1, NEUROCYTOCHIM FONCTIONNELLE LAB, F-33405 TALENCE, FRANCE
3. INSERM, U156, F-59045 LILLE, FRANCE
Publisher: MASSON EDITEUR, 120 BLVD SAINT-GERMAIN, 75280 PARIS 06, FRANCE
Subject Category: Endocrinology & Metabolism
IDS Number: JA805
ISSN: 0003-4266

Calvin Cycle pathway

Overview of the Calvin Cycle pathway. Original work by Mike Jones

Suberin: waxy, waterproof chemical in some plant cells, notably cork (in stems) and endodermis cells (in roots). Suberin is an extremely complex and irregular material, like lignin -- with which it shares some similarities. Suberin is composed of two physically separated domains: the aliphatic and phenolic. The phenolic domain is rather lignin-like, but with even greater variability, and built on the same basic unit of a di- or tri-hydroxyphenyl group attached to a three-carbon chain, variously oxidized and integrated with the carbohydrates of the cell walls. Perhaps the most common building block is ferulic acid: formally, 3-(2'-methoxy-3'-hydroxyphenyl)-propenoic acid. Distally, the phenolic domain is attached at points by ester linkages to glycerol. The remaining hydroxyls of the glycerol molecule are ester-linked to some strange-looking C-18 to C-30 lipids. These lipids are substituted at C9-10 with one or two hydroxyls, or even with an epoxide link between the two carbons. Finally the ω- position may be oxidized to a carboxylate (alone or esterized to glycerol) or hydroxyl (alone or esterised to ferulic acid). Variations allow for cross-linkage to other suberin molecules via the 9-10 or ω positions. Image adapted from Bernards (2002).

Suberin is a plant cell wall modification that involves the deposition of both a poly(phenolic) and a poly(aliphatic) domain within the same tissue. As such, the deposition of suberin represents the coordinate regulation of both fatty acid metabolism (giving rise to suberin-specific aliphatic compounds) and phenylpropanoid metabolism (givin rise to suberin-specific phenolic compounds). Over the past decade, we have used chemical analyses to identify target metabolites unique to suberin and biochemical analyses to identify unique steps in their biosynthesis. We are now in a position to clone and characterize the genes that encode the enzymes for these unique biochemical steps. With these genes in hand, we will be able to ask questions about the regulation of suberization and study the mechanism(s) by which disparate pathways converge to make the unique material known as suberin.

In addition, we are interested in the role(s) for which plants use secondary metabolites to interact with other organisms. Recently, we have focused on the role of ginsenosides (e.g., Rb1 at right) in the interaction between ginseng and one of its major pathogens, Pythium irregulare.

Our research group is located on the fourth floor of the North Campus Building, forming part of the Environmental Stress Biology Group. Other members of the ESBG include Dr. Norman Huner, Dr. Denis Maxwell and Dr. Charlie Trick.