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Biomedical subjects

D E Cooke

Publications and source records attributed to D E Cooke.

8 recordsLinked to original sources
PubMed2000

A molecular phylogeny of Phytophthora and related oomycetes.

Phylogenetic relationships among 50 Phytophthora species and between Phytophthora and other oomycetes were examined on the basis of the ITS sequences of genomic rDNA. Phytophthora grouped with Pythium, Peronospora, and Halophytophthora, distant from genera in the Saprolegniales. Albugo was intermediate between these two groups. Unlike Pythium, Phytophthora was essentially monophyletic, all but three species forming a cluster of eight clades. Two clades contained only species with nonpapillate sporangia. The other six clades included either papillate and semipapillate, or semipapillate and nonpapillate types, transcending traditional morphological groupings, which are evidently not natural assemblages. Peronospora was related to P. megakarya and P. palmivora and appears to be derived from a Phytophthora that has both lost the ability to produce zoospores and become an obligate biotroph. Three other Phytophthoras located some distance from the main Phytophthora-Peronospora cluster probably represent one or more additional genera.

DNA, Fungal↗
PubMed2000

A potato gene encoding a WRKY-like transcription factor is induced in interactions with Erwinia carotovora subsp. atroseptica and Phytophthora infestans and is coregulated with class I endochitinase expression.

A potato gene encoding a putative WRKY protein was isolated from a cDNA library enriched by suppression subtractive hybridization for sequences upregulated 1 h postinoculation with Erwinia carotovora subsp. atroseptica. The cDNA encodes a putative polypeptide of 172 amino acids, containing a single WRKY domain with a zinc finger motif and preceded by a potential nuclear localization site. St-WRKY1 was strongly upregulated in compatible, but only weakly in incompatible, interactions with Phytophthora infestans where, in all cases, it was coregulated with class I endochitinase, associating its expression with a known defense response. Whereas St-WRKY1 was strongly induced by E. carotovora culture filtrate (CF), confirming it to be an elicitor-induced gene, no such induction was detected after treatment with salicylic acid, methyl jasmonate, ethylene, or wounding. St-WRKY1 was upregulated by treatment of potato leaves with CFs from recombinant Escherichia coli containing plasmids expressing E. carotovora pectate lyase genes pelB and pelD, suggesting that either proteins encoded by these genes, or oligogalacturonides generated by their activity, elicit a potato defense pathway associated with St-WRKY1.

Amino Acid Motifs↗
PubMed1999

Origin of a new Phytophthora pathogen through interspecific hybridization.

Plant disease epidemics resulting from introductions of exotic fungal plant pathogens are a well known phenomenon. An associated risk-that accelerated pathogen evolution may be occurring as a consequence of genetic exchange between introduced, or introduced and resident, fungal pathogens-is largely unrecognized. This is, in part, because examples of natural, interspecific hybridization in fungi are very rare. Potential evolutionary developments range from the acquisition of new host specificities to emergence of entirely new pathogen taxa. We present evidence from cytological behavior, additive nucleotide bases in repetitive internal transcribed spacer regions of the rRNA-encoding DNA (rDNA), and amplified fragment length polymorphisms of total DNA that a new, aggressive Phytophthora pathogen of alder trees in Europe comprises a range of heteroploid-interspecific hybrids involving a Phytophthora cambivora-like species and an unknown taxon similar to Phytophthora fragariae. The hybrids' marked developmental instabilities, unusual morphological variability, and evidence for recombination in their internal transcribed spacer profiles indicates that they are of recent origin and that their evolution is continuing. The likelihood of such evolutionary events may be increasing as world trade in plants intensifies. However, routine diagnostic procedures currently in use are insufficiently sensitive to allow their detection.

Biological Evolution↗
PubMed1995

Recognising promoter sequences using an artificial immune system.

We have developed an artificial immune system (AIS) which is based on the human immune system. The AIS possesses an adaptive learning mechanism which enables antibodies to emerge which can be used for classification tasks. In this paper, we describe how the AIS has been used to evolve antibodies which can classify promoter containing and promoter negative DNA sequences. The DNA sequences used for teaching were 57 nucleotides in length and contained procaryotic promoters. The system classified previously unseen DNA sequences with an accuracy of approximately 90%.

Algorithms↗
PubMed1995

Death in the desert.

David Cooke enjoyed eight weeks of general practice in the Northern Territory, but he expresses some misgivings about the health of some Territorians. His experiences in the Outback contrast vividly with his time in Saudi Arabia, which he wrote about in the January issue of Australian Family Physician.

Alcoholism↗
PubMed1994

Baclofen poisoning in children.

Six cases of acute baclofen (LIORESAL) overdose in children are reported. Rapid onset of central nervous system depression with respiratory depression was present to a greater or lesser degree in all patients. Agitation, convulsions and ataxia were also seen. The entire cohort responded to supportive management. An accurate assessment of the quantity of drug ingested was not possible. The need for education on safe drug storage and disposal is emphasized.

Ataxia↗
PubMed1990

Australian trial of topical minoxidil and placebo in early male pattern baldness.

One hundred and sixty nine men with early male pattern baldness (androgenic alopecia) were treated in a random, double-blind fashion with either 2% minoxidil solution or placebo vehicle for 24 weeks, one ml applied twice daily. After 24 weeks all patients received the active solution until week 48. After 24 weeks the minoxidil treated patients had increased their non-vellus hair counts significantly more than the placebo treated group; means were 37.6 and 8.8 hairs per reference area, 95% C.I. for difference = 10.85 to 60.75. The rate of non-vellus hair regrowth was also greater among minoxidil treated patients than placebo treated patients. Nine (12.5%) evaluable minoxidil treated patients compared with 2 (2.7%) evaluable placebo treated patients reported moderate or dense hair regrowth at week 24. Minimal regrowth was reported by 18 (25%) active group and 15 (20%) placebo group patients. The investigators considered that 3 (2%) of the minoxidil group and none of the placebo group had moderate hair regrowth and that none had dense regrowth. After 48 weeks treatment 28 (23%) patients considered that they had moderate hair regrowth and the investigators considered that 14 (12%) patients had moderate regrowth. None had dense growth. No serious adverse reactions or deaths were reported. Minoxidil solution appeared to be an efficacious and safe treatment for early androgenic alopecia.

Administration, Cutaneous↗