bluuebunny/crossref_metadata_2025 huggingface dataset:
Innate immune responses of a lepidopteran insect, Manduca sexta
Authors: Kanost Michael R. , Jiang Haobo , Yu Xiao‐Qiang
Published: March 2004

Summary:  Many innate immune mechanisms are conserved throughout the animal kingdom. Manduca sexta, a widely used model for insect biochemical research, employs these mechanisms to defend against invading pathogens and parasites. We have isolated from M. sexta hemolymph a group of proteins (hemolin, peptidoglycan recognition proteins, β‐1,3‐glucan recognition proteins, and C‐type lectins), which serve as a surveillance mechanism by binding to microbial surface molecules (e.g. peptidoglycan, lipopolysaccharide, lipoteichoic acid, and β‐1,3‐glucan). The binding triggers diverse responses such as phagocytosis, nodule formation, encapsulation, melanization, and synthesis of anti‐microbial peptides/proteins. Some of these responses are mediated and coordinated by serine proteinase cascades, analogous to the complement system in mammals. Our current research is focused on the proteolytic activation of prophenoloxidase (proPO) – a reaction implicated in melanotic encapsulation, wound healing, and protein cross‐linking. We have isolated three proPO‐activating proteinases, each of which requires serine proteinase homologs as a cofactor for generating active phenoloxidase. The proteinases and proteinase‐like molecules, containing one to two clip domains at their amino‐terminus, are acute‐phase proteins induced upon an immune challenge. Inhibitory regulation of the proteinases by serpins and association of the proteinase homologs with a bacteria‐binding lectin are important for ensuring a localized defense response. Additional serine proteinases expressed in M. sexta hemocytes and fat body have been discovered. Future research efforts will be aimed at elucidating the proteinase cascade for proPO activation and investigating the roles of proteinases in other immune responses such as processing of plasmatocyte‐spreading peptide.
Comparative and functional genomics of the innate immune system in the malaria vector Anopheles gambiae
Authors: Christophides George K. , Vlachou Dina , Kafatos Fotis C.
Published: March 2004

Summary:  In much of Africa, the mosquito Anopheles gambiae is the major vector of human malaria, a devastating infectious disease caused by Plasmodium parasites. Vector and parasite interact at multiple stages and locations, and the nature and effectiveness of this reciprocal interaction determines the success of transmission. Many of the interactions engage the mosquito's innate immunity, a primitive but very effective defense system. In some cases, the mosquito kills the parasite, thus blocking the transmission cycle. However, not all interactions are antagonistic; some represent immune evasion. The sequence of the A. gambiae genome revealed numerous potential components of the innate immune system, and it established that they evolve rapidly, as summarized in the present review. Their rapid evolution by gene family expansion diversification as well as the prevalence of haplotype alleles in the best‐studied families may reflect selective adaptation of the immune system to the exigencies of multiple immune challenges in a variety of ecologic niches. As a follow‐up to the comparative genomic analysis, the development of functional genomic methodologies has provided novel opportunities for understanding the immune system and the nature of its interactions with the parasite. In this context, identification of both Plasmodium antagonists and protectors in the mosquito represents a significant conceptual advance. In addition to providing fundamental understanding of primitive immune systems, studies of mosquito interactions with the parasite open unprecedented opportunities for novel interventions against malaria transmission. The generation of transgenic mosquitoes that resist malaria infection in the wild and the development of antimalarial ‘smart sprays’ capable of disrupting interactions that are protective of the parasite, or reinforcing others that are antagonistic, represent technical challenges but also immense opportunities for improvement of global health.
The immune response of Drosophila melanogaster
Authors: Leclerc Vincent , Reichhart Jean‐Marc
Published: March 2004

Summary:  The response of the fruit fly Drosophila melanogaster to various microorganism infections relies on a multilayered defense. The epithelia constitute a first and efficient barrier. Innate immunity is activated when microorganisms succeed in entering the body cavity of the fly. Invading microorganisms are killed by the combined action of cellular and humoral processes. They are phagocytosed by specialized blood cells, surrounded by toxic melanin, or lysed by antibacterial peptides secreted into the hemolymph by fat body cells. During the last few years, research has focused on the mechanisms of microbial recognition by various pattern recognition receptors and of the subsequent induction of antimicrobial peptide expression. The cellular arm of the Drosophila innate immune system, which was somehow neglected, now constitutes the new frontier.
The roles of JAK/STAT signaling in Drosophila immune responses
Authors: Agaisse Hervé , Perrimon Norbert
Published: March 2004

Summary:  Innate immune responses are mediated by the activation of various signaling processes. Here, we describe our current knowledge on Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signaling in the Drosophila immune response. First, we briefly introduce the main effectors involved in the humoral and cellular responses, such as anti‐bacterial peptides and hemocytes. Second, we describe the canonical JAK/STAT‐signaling pathway, as established from extensive studies in mammalian systems, and we introduce the Drosophila components of the JAK/STAT pathway, as discovered from studies on embryonic development. Third, we describe the various roles of JAK/STAT signaling in both humoral and cellular responses. We present the JAK/STAT‐dependent humoral factors, such as the thioester‐containing proteins and the Tot peptides, produced by the fat body in response to septic injury. We also discuss the possible involvement of the JAK/STAT pathway in cellular responses, including hemocyte proliferation and differentiation. Finally, we present how cytokines, such as Upd3, might contribute to the integration of the immune responses at the organism level by orchestrating the response of various immune cells and organs, such as fat body, hemocytes, and lymph glands.
The Kurds in Iraq
Authors: Gunter Michael M. , Natali Denise , Olson Robert , Özcan Nihat Ali , Salih Khaled , Yavuz M. Hakan
Published: March 2004

The following briefs are edited versions of papers presented at the annual meeting of the Middle East Studies Association in Anchorage, Alaska, November 8, 2003. The editors were Hakan Yavuz and Michael Gunter, whose papers are included below.

Why Kurdish Statehood is Unlikely, Michael M. Gunter, professor of political science, Tennessee Technological University, Cookeville, Tennessee

Transnational Networks: New Opportunities and Constraints for Kurdish Statehood, Denise Natali, visiting research fellow, Washington Kurdish Institute (WKI); director of WKI's transnational project

Turkey and Kurdistan‐Iraq, 2003, Robert Olson, professor of Middle East and Islamic history, University of Kentucky

Could a Kurdish State Be Set Up in Iraq?, Nihat Ali Özcan, author of PKK (Kurdistan ýpçi Partisi) Tarihi, Ideolojisi ve Yönetimi (Ankara: Asam, 1999)

Kurdish Reality in an Emerging Iraq, Khaled Salih, University of Southern Denmark

Provincial Not Ethnic Federalism in Iraq, M. Hakan Yavuz, associate professor of political science, University of Utah
Molecular polymorphism of ABO blood group gene in Austronesian and non‐Austronesian populations in Oceania
Authors: Ohashi J. , Naka I. , Ohtsuka R. , Inaoka T. , Ataka Y. , Nakazawa M. , Tokunaga K. , Matsumura Y.
Published: March 2004

Abstract:  A number of archeological, linguistic, and genetic studies have been carried out on the peopling of the Pacific, while the origin of Polynesians or the Lapita people is still open to debate. The Lapita people are believed to have populated the Bismarck Archipelago more than 3600 years ago. However, their Melanesian descendants still living in the Bismarck Archipelago have not been genetically clarified yet. To address this question, polymorphism of the ABO blood group gene was investigated in the following three populations who are considered to be almost free from recent admixtures: (i) Balopa islanders as Austronesian (AN)‐speaking Melanesians living in the northwestern end of the Bismarck Archipelago; (ii) Gidra as non‐Austronesian (NAN)‐speaking Melanesians in southwestern lowlands of Papua New Guinea; and (iii) Tongan living in Ha'apai island as AN‐speaking Polynesians. Interestingly, there were marked differences in allele frequencies of ABO*A101 and ABO*A102 among the three populations. The allele frequencies of ABO*A101 and ABO*A102 were 7.9 and 19.3% in Balopa, 23.2 and 0.0% in Gidra, and 2.9 and 25.0% in Tongan. Both phylogenetic and correspondence analyses suggested that Balopa was more close to Tongan than to Gidra and that Balopa was genetically placed between Tongan and Asian populations. Our results imply that Balopa may be Melanesian descendants of the Lapita people who populated the Bismarck Archipelago.
Trypanosoma brucei oleate desaturase may use a cytochrome b5‐like domain in another desaturase as an electron donor
Authors: Petrini Guillermo A. , Altabe Silvia G. , Uttaro Antonio D.
Published: March 2004

An open reading frame with fatty acid desaturase similarity was identified in the genome of Trypanosoma brucei. The 1224 bp sequence specifies a protein of 408 amino acids with 59% and 58% similarity to Mortierella alpina and Arabidopsis thalianaΔ12 desaturase, respectively, and 51% with A. thalianaω3 desaturases. The histidine tracks that compose the iron‐binding active centers of the enzyme were more similar to those of the ω3 desaturases. Expression of the trypanosome gene in Saccharomyces cerevisiae resulted in the production of fatty acids that are normally not synthesized in yeast, namely linoleic acid (18:2Δ9,12) and hexadecadienoic acid (16:2Δ9,12), the levels of which were dependent on the culture temperature. At low temperature, the production of bi‐unsaturated fatty acids and the 16:2/18:2 ratio were higher. Transformed yeast cultures supplemented with 19:1Δ10 fatty acid yielded 19:2Δ10,13, indicating that the enzyme is able to introduce a double bond at three carbon atoms from a pre‐existent olefinic bond. The expression of the gene in a S. cerevisiae mutant defective in cytochrome b5 showed a significant reduction in bi‐unsaturated fatty acid production, although it was not totally abolished. Based on the regioselectivity and substrate preferences, we characterized the trypanosome enzyme as a cytochrome b5‐dependent oleate desaturase. Expression of the ORF in a double mutant (ole1Δ,cytb5Δ) abolished all oleate desaturase activity completely. OLE1 codes for the endogenous stearoyl‐CoA desaturase. Thus, Ole1p has, like Cytb5p, an additional cytochrome b5 function (actually an electron donor function), which is responsible for the activity detected when using the cytb5Δ single mutant.
NF‐κB‐ and c‐Jun‐dependent regulation of human cytomegalovirus immediate‐early gene enhancer/promoter in response to lipopolysaccharide and bacterial CpG‐oligodeoxynucleotides in macrophage cell line RAW 264.7
Authors: Lee Younghee , Sohn Wern‐Joo , Kim Doo‐Sik , Kwon Hyung‐Joo
Published: March 2004

The cytomegalovirus immediate‐early (CMV IE) gene enhancer/promoter regulates the expression of immediate‐early gene products and initiation of CMV replication. TNF‐α and lipopolysaccharide (LPS) strongly activate the promoter, possibly involving NF‐κB. CpG‐oligodeoxynucleotides (CpG‐ODNs), which contain unmethylated CpG dinucleotides in the context of particular base sequences, have gained attention because of their stimulating effects, via NF‐κB, which have a strong innate immune response. To study the effects of LPS and CpG‐ODNs, as well as the mechanisms of their actions regarding CMV IE enhancer/promoter activation, we used a macrophage cell line, RAW 264.7. Stimulation of the cells with LPS or CpG‐ODNs resulted in the activation of the CMV IE enhancer/promoter. We examined the involvement of NF‐κB and c‐Jun transcription factors by promoter deletion/site‐specific mutation analysis and ectopic expression, and found them to have additive effects. Involvement of myeloid differentiation protein, an upstream regulator of NF‐κB and c‐Jun, was also investigated. Experimental results indicate that both LPS‐induced and CpG‐ODN‐induced activations of CMV IE enhancer/promoter are mediated by Toll‐like receptor signaling molecules. Several lines of evidence suggest the potential contribution of bacterial infection in CMV reactivation along with the potential application of CpG‐ODNs in gene therapy as a stimulator for the optimal expression of target genes under the control of the CMV IE enhancer/promoter.
Chromophore selectivity in bacterial phytochromes
Authors: Quest Benjamin , Gärtner Wolfgang
Published: March 2004

Bacterial phytochromes (Bphs) are ancestors of the well characterized plant photoreceptors. Whereas plant phytochromes perform their photoisomerization exclusively via a covalently bound bilin chromophore, Bphs are variable in their chromophore selection. This is demonstrated in the cyanobacterium Calothrix PCC7601 that expresses two Bphs, CphA and CphB. CphA binds phycocyanobilin (PCB) covalently, whereas CphB, lacking the covalently binding cysteine of the plant phytochromes, carries biliverdin IXα (BV) as the chromophore. Our experiments elucidate the different modes of chromophore–protein interaction in CphA and CphB and offer a rationale for their chromophore selectivity. The tight binding of BV by CphB prevents PCB from competing for the binding cavity. Even when the chromophore‐binding cysteine has been inserted (CphB‐mutant L266C), PCB replaces BV very slowly, indicating the tight, but not irreversible binding of BV. The mutant CphB L266C showed a redox‐sensitivity with respect to its PCB binding mode: under reducing conditions, the chromoprotein assembly leads to spectra indicative for a covalent binding, whereas absence of dithiothreitol or its removal prior to assembly causes spectra indicative for noncovalent binding. Regarding the CphB‐type Bphs lacking the covalently binding cysteine, our results support the involvement of the succeeding histidine residue in chromophore fixation via a Schiff base‐like bond between the bilin A‐ring carbonyl and the histidine imidazole group. The assembly process and the stability of the holo‐proteins were strongly influenced by the concentration of added imidazole (mimicking the histidine side‐chain), making the attachment of the chromophore via the histidine more likely than via another cysteine of the protein.
The transporters Pdr5p and Snq2p mediate diazaborine resistance and are under the control of the gain‐of‐function allele PDR1‐12
Authors: Wehrschütz‐Sigl Eva , Jungwirth Helmut , Bergler Helmut , Högenauer Gregor
Published: March 2004

The spontaneous acquisition of resistance to a variety of unrelated cytotoxic compounds has important implications in medical treatment of infectious diseases and anticancer therapy. In the yeast Saccharomyces cerevisiae this phenomenon is caused by overexpression of membrane efflux pumps and is called pleiotropic drug resistance. We have found that allelic forms of the genes for the transcription activators Pdr1p and Pdr3p, designated PDR1‐12 and PDR3‐33, respectively, mediate resistance to diazaborine. Here we demonstrate that the transporters Pdr5p and Snq2p are involved in diazaborine detoxification. We report that in the PDR3‐33 mutant diazaborine resistance is exerted mainly via overexpression of the PDR5 and SNQ2 genes, while in the PDR1‐12 mutant, additional genes, i.e. the Yap1p target genes FLR1 and YCF1, are also involved in diazaborine detoxification. In addition, we show that in the presence of cycloheximide or diazaborine PDR5 can be activated by additional transcription factors beside Pdr1p and Pdr3p.
Trichostatin A reduces hormone‐induced transcription of the MMTV promoter and has pleiotropic effects on its chromatin structure
Authors: Åstrand Carolina , Klenka Tomas , Wrange Örjan , Belikov Sergey
Published: March 2004

The deacetylase inhibitor trichostatin A (TSA) has long been used to study the relationship between gene transcription and the acetylation status of chromatin. We have used Xenopus laevis oocytes to study the effects of TSA on glucocorticoid receptor (GR)‐dependent transcription and we have related these effects to changes in the chromatin structure of a reporter mouse mammary tumor virus (MMTV) promoter. We show that TSA induces a low level of constitutive transcription. This correlates with a change of acetylation pattern and a more open chromatin structure over the MMTV chromatin, and with specific acetylation and remodeling events in the promoter region. Specifically, a repositioning of initially randomly positioned nucleosomes along the distal MMTV long terminal repeat is seen. This nucleosome rearrangement is similar to the translational nucleosome positioning that occurs upon hormone activation. We also note a reduced hormone response in the presence of TSA. TSA effects have for a long time been associated with transcriptional activation and chromatin opening through inhibition of the deacetylation of histones. However, our results and those of others show that TSA‐induced changes in expression and chromatin structure can be quite different in different promoter contexts and, thus, the effects of TSA are more complex than previously believed.
Quantitative analysis, using MALDI‐TOF mass spectrometry, of the N‐terminal hydrolysis and cyclization reactions of the activation process of onconase
Authors: Ribó Marc , Bosch Montserrat , Torrent Gerard , Benito Antoni , Beaumelle Bruno , Vilanova Maria
Published: March 2004

Onconase, a member of the ribonuclease superfamily, is a potent cytotoxic agent that is undergoing phase II/III human clinical trials as an antitumor drug. Native onconase from Rana pipiens and its amphibian homologs have an N‐terminal pyroglutamyl residue that is essential for obtaining fully active enzymes with their full potential as cytotoxins. When expressed cytosolically in bacteria, Onconase is isolated with an additional methionyl (Met1) residue and glutaminyl instead of a pyroglutamyl residue at position 1 of the N‐terminus and is consequently inactivated. The two reactions necessary for generating the pyroglutamyl residue have been monitored by MALDI‐TOF MS. Results show that hydrolysis of Met(−1), catalyzed by Aeromonas aminopeptidase, is optimal at a concentration of ≥ 3 m guanidinium‐chloride, and at pH 8.0. The intramolecular cyclization of glutaminyl that renders the pyroglutamyl residue is not accelerated by increasing the concentration of denaturing agent or by strong acid or basic conditions. However, temperature clearly accelerates the formation of pyroglutamyl. Taken together, these results have allowed the characterization and optimization of the onconase activation process. This procedure may have more general applicability in optimizing the removal of undesirable N‐terminal methionyl residues from recombinant proteins overexpressed in bacteria and providing them with biological and catalytic properties identical to those of the natural enzyme.
Membrane interaction and cellular internalization of penetratin peptides
Authors: Christiaens Bart , Grooten Johan , Reusens Michael , Joliot Alain , Goethals Marc , Vandekerckhove Joël , Prochiantz Alain , Rosseneu Maryvonne
Published: March 2004

Penetratin is a 16‐residue peptide [RQIKIWFQNRRMKWKK(43–58)] derived from the Antennapedia homeodomain, which is used as a vector for cellular internalization of hydrophilic molecules. In order to unravel the membrane translocation mechanism, we synthesized new penetratin variants. The contribution of the positively charged residues was studied by double substitutions of Lys and/or Arg residues to Ala, while the specific contribution of Trp48 and Trp56 was studied by individual substitution of these residues to Phe. Trp fluorescence titrations demonstrated the importance of the positively charged residues for the initial electrostatic interaction of the peptide with negatively charged vesicles. In contrast, none of the Trp residues seemed critical for this initial interaction. Trp fluorescence quenching experiments showed that penetratin lies close to the water–lipid interface in a tilted orientation, while circular dichroism indicated that lipid binding increased the α‐helical structure of the peptides. The R53A/K57A and R52A/K55A substitutions increased calcein leakage and decreased vesicle aggregation compared to wild‐type penetratin. These variants insert deeper into the lipid bilayer, due to an increased hydrophobic environment of Trp56. The W48F and W56F substitutions had a minor effect on membrane insertion and destabilization. Cellular internalization of the R53A/K57A, R52A/K55A and K46A/K57A variants by MDCK cells was similar to wild‐type penetratin, as shown by flow cytometry. Moreover, residue Trp48 specifically contributed to endocytosis‐independent internalization by MDCK cells, as demonstrated by the lower uptake of the W48F variant compared to wild‐type penetratin and to the W56F variant. None of the penetratin variants was haemolytic or cytotoxic.
Effect of Irrigation Type on Inoculum Density of Macrophomina phaseolina in Melon Fields in Arizona
Authors: Nischwitz C. , Olsen M. , Rasmussen S.
Published: March 2004

Charcoal rot, caused by Macrophomina phaseolina, has become increasingly problematic for melon growers using subsurface drip irrigation in Arizona; but has rarely been observed in fields with furrow irrigation. Since the relationship between increasing incidence of charcoal rot on melon and irrigation type is unknown, studies were initiated to determine the effects of edaphic factors on inoculum density. Soil samples were collected once from fields irrigated by subsurface drip, with and without plastic mulch, and by furrow at 10, 20 and 30 cm depths. Samples were analysed for percentage soil moisture, pH, salinity and inoculum density. Percentage soil moisture was significantly higher at 20 and 30 cm depths in the furrow‐irrigated field compared with the drip‐irrigated field with plastic mulch, but not in the field without plastic mulch. Average minimum and maximum temperatures and inoculum density were significantly lower at all three depths in the furrow‐irrigated field compared with both types of drip irrigation. pH was significantly higher in the furrow‐irrigated field compared with both types of drip irrigation at 20 and 30 cm depths but not at 10 cm depth. Differences in inoculum densities of M. phaseolina suggest that drip irrigation may contribute to higher disease incidences.
Effect of Grapevine Leafroll on the Photosynthesis of Field Grown Grapevine Plants (Vitis vinifera L. cv. Lagrein)
Authors: Bertamini M. , Muthuchelian K. , Nedunchezhian N.
Published: March 2004

We have studied the effect of grapevine leafroll infection on some features of the thylakoids from field grown grapevine (Vitis vinifera L.) leaves. Changes in photosynthetic pigments, soluble proteins, ribulose‐1,5‐bisphosphate carboxylase (RuBP), nitrate reductase, photosynthetic activities and thylakoid membrane proteins were investigated. The level of total chlorophyll (Chl) and carotenoids were reduced in virus‐infected leaves. Similar results were also observed for soluble proteins and RuBP case activity. The in vivo nitrate reductase activity was significantly reduced in infected leaves. Virus infection considerably decreased leaf net photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (E) in grapevine leaves. When various photosynthetic activities were followed in isolated thylakoids, virus infection caused marked inhibition of whole chain and photosystem (PS) II activity while the inhibition of PSI activity was only marginal. The artificial exogenous electron donors, diphenyl carbazide and hydroxylamine (NH2OH) significantly restored the loss of PSII activity in infected leaves. The same results were obtained when Fv/Fm was evaluated by Chl fluorescence measurements. The marked loss of PSII activity in infected leaves could be due to the loss of 47, 43, 33, 28–25, 23 and 17 kDa polypeptides. It is concluded that virus infection inactivates the donor side of PSII. This conclusion was confirmed by immunological studies showing that the content of the 33 kDa protein of the water‐splitting complex was diminished significantly in infected leaves.
Molecular Characterization of 16S Ribosomal DNA and Phylogenetic Analysis of Two X‐disease Group Phytoplasmas Affecting China‐tree (Melia azedarach L.) and Garlic (Allium sativum L.) in Argentina
Authors: Galdeano E. , Torres L. E. , Meneguzzi N. , Guzmán F. , Gomez G. G. , Docampo D. M. , Conci L. R.
Published: March 2004

Two phytoplasmas closely related to the X‐disease group were associated with China‐tree (Melia azedarach L.) and garlic (Allium sativum L.) decline diseases in Argentina. The present work was aimed at studying their phylogenetic relationship based on molecular characterization of the 16S ribosomal DNA sequences. Phytoplasma DNAs were obtained from naturally infected China‐tree and garlic plants from different geographical isolates. The results from analysis of restriction fragment length polymorphisms and nucleotide sequences of the 16S rDNA showed the affiliation of China‐tree and garlic decline phytoplasmas to the 16SrIII (X‐disease group), subgroups B and J, respectively. Both organisms had high sequence similarities in the 16SrDNA nucleotide sequence with the Chayote witches’ broom phytoplasma from Brazil. The phylogenetic tree, constructed by parsimony analysis, grouped the Garlic decline, China‐tree decline, Chayote witches’ broom and Clover yellow edge phytoplasmas into a cluster separated from the other phytoplasmas of the X‐disease group.
Influence of aquatic microbiota on the survival in water of the human and eel pathogen Vibrio vulnificus serovar E
Authors: Marco‐Noales Ester , Biosca Elena G. , Rojo Carmen , Amaro Carmen
Published: March 2004

The eel and human pathogen Vibrio vulnificus serovar E (biotype 2) is seldom isolated from natural waters, although it can survive in sterilized artificial seawater microcosms for years. The main objective of the present study was to investigate whether aquatic microbiota can limit its survival and recovery from water samples. A set of preliminary experiments of survival in microcosms containing natural seawater and water from eel farms showed that the persistence of this pathogen was mainly controlled by grazing, and secondarily by bacterial competition. The bacterial competition was further analysed in artificial seawater microcosms co‐inoculated with selected virulent serovar E (VSE) strains and potential competitors. Competitors included V. vulnificus biotype 1 isolates and strains of selected species that can grow on the selective media designed for V. vulnificus isolation from water samples. Evidences of bacterial competition that was detrimental for VSE recovery were recorded. Thus, some species produced a deleterious effect on VSE strains under starvation, and others were able to use the resources more efficiently under nutrient input. These results suggest that an overgrowth of more efficient competitor bacteria in conventional media used for isolation of V. vulnificus could mask the recovery of VSE strains and explain the scarcity of reports on the isolation of this human and eel pathogen from natural waters.
Investigations on cyanobacterial diversity in a shallow estuary (Southern Baltic Sea) including genes relevant to salinity resistance and iron starvation acclimation
Authors: Geiß Ulrike , Selig Uwe , Schumann Rhena , Steinbruch Robert , Bastrop Ralf , Hagemann Martin , Schoor Arne
Published: March 2004

The cyanobacterial diversity in the pelagic of a shallow estuary at the Southern Baltic Sea has been investigated by a combination of classical morphological data and a polymerase chain reaction (PCR)‐based molecular approach. The aim of the study was to investigate possible changes in the composition of the cyanobacterial community along the salinity and nutrient gradients. For this purpose partial gene sequences of cyanobacterial 16S rDNA and of two functional genes (ggpS– salinity tolerance marker, isiA– iron starvation marker) were amplified and compared with total community DNA. Random distribution of ggpS genotypes along the salinity gradient suggests that synthesis of the osmolyte glucosylglycerol is not restricted to higher salinity sampling sites. Most of the isiA sequences formed a new homogenous cluster in a phylogenetic tree, which indicates that the indigenous cyanobacterial community comprises a group of unknown species. Minimum iron concentrations, which can activate isiA transcription in model cyanobacteria, occurred at a few sampling sites with high phytoplankton biomass and moderate salinity. Nevertheless, isiA expression could be detected at all sampling sites, which indicated restricted iron supply to cyanobacterial phytoplankton in summer.
Quantification of gene expression in methanotrophs by competitive reverse transcription‐polymerase chain reaction
Authors: Han Jong‐In , Semrau Jeremy D.
Published: March 2004

To improve the monitoring of methanotrophic activity, a competitive reverse transcription‐polymerase chain reaction (RT‐PCR) methodology was developed. Homologous internal RNA standards were created for mmoX and pmoA, genes encoding polypeptides of sMMO and pMMO, respectively. Using specific primer sets, expression of sMMO and pMMO could be quantified by means of competitive RT‐PCR and capillary electrophoresis with uncoated bare‐fused silica columns and UV detection. Using this technique, it was discovered that the amount of mRNA transcript for both mmoX and pmoA correlated well with whole‐cell sMMO and pMMO activity respectively. A method for soil RNA extraction was also developed to utilize this RNA quantification technique for the monitoring of methanotrophic activity in situ. In a model soil slurry system with a background concentration of 2.9 µM copper, it was found that only pmoA was transcribed by cells capable of expressing both forms of MMO. As pMMO and sMMO have very different substrate ranges and kinetics, this methodology may prove useful for optimizing in situ bioremediation by methanotrophs. Provided sufficient sequence information is available to create specific primer sets, these techniques can be applied for monitoring and measuring the activity of other microbial communities in situ.
Strain‐specific genomic regions of Ruminococcus flavefaciens FD‐1 as revealed by combinatorial random‐phase genome sequencing and suppressive subtractive hybridization
Authors: Antonopoulos Dionysios A. , Nelson Karen E. , Morrison Mark , White Bryan A.
Published: March 2004

Two closely related strains of the Gram‐positive, cellulolytic ruminal bacterium Ruminococcus flavefaciens were compared at the genomic level by suppressive subtractive hybridization. The two strains investigated in this study differ by 1.94% in their respective 16S rDNA genes. Three hundred and eighty‐four PCR‐amplified products were cloned and then screened for their strain identity by dot blot hybridization. Based on redundancy percentages of the clones sequenced, 9.5% of the genome of the R. flavefaciens FD‐1 strain is not present in the JM1 strain. The majority of identities of individual cloned subtracted products (642 bp average length) bore no relation to deposited sequences in GenBank (42% of the subtracted library), whereas of those with putative assigned functions 7% are loosely associated with fibre‐degradation, 6% with insertion elements, transposons and phage‐like ORFs, 5% with cell membrane associated proteins and 3% with signal transduction. Subtracted sequences were then supplemented with the draft (2 × coverage) genome sequence of R. flavefaciens FD‐1 to indicate potential regions of rearrangement within the genome, including a novel insertion sequence.
Fatty acid biosynthesis is involved in solvent tolerance in Pseudomonas putida DOT‐T1E
Authors: Segura Ana , Duque Estrella , Rojas Antonia , Godoy Patricia , Delgado Antonio , Hurtado Ana , E. Cronan John , Ramos Juan‐Luis
Published: March 2004

The unusual tolerance of Pseudomonas putida DOT‐T1E to toluene is based on the extrusion of this solvent by constitutive and inducible efflux pumps and rigidification of its membranes via phospholipid alterations. Pseudomonas putida DOT‐T1E‐109 is a solvent‐sensitive mutant. Mutant cells were less efficient in solvent extrusion than the wild‐type cells, as shown by the limited efflux of 14C‐1,2,4‐trichlorobenzene from the cell membranes, despite the fact that the efflux pumps are overexpressed as a result of increased expression of the ttgDEF and ttgGHI efflux pump operons. This limitation could be the result of alterations in the outer membrane because the mutant cells released more β‐lactamase to the external medium than the wild‐type cells. The mutant P. putida DOT‐T1E‐109 showed negligible synthesis of fatty acids in the presence of sublethal concentrations of toluene as revealed by analysis of 13CH3‐13COOH incorporation into fatty acids. In contrast, the mutant strain in the absence of solvents, and the wild‐type strain, both in the presence and in the absence of toluene, incorporated 13CH3‐13COOH at a high rate into de novo synthesized lipids. The mutation in P. putida DOT‐T1E‐109 increases sensitivity to the solvent because of a limited efflux of the solvent from the cell membranes with the concomitant inhibition of fatty acid biosynthesis.
Optimization of diagnostic microarray for application in analysing landfill methanotroph communities under different plant covers
Authors: Stralis‐Pavese Nancy , Sessitsch Angela , Weilharter Alexandra , Reichenauer Thomas , Riesing Johann , Csontos József , Murrell J. Colin , Bodrossy Levente
Published: March 2004

Landfill sites are responsible for 6–12% of global methane emission. Methanotrophs play a very important role in decreasing landfill site methane emissions. We investigated the methane oxidation capacity and methanotroph diversity in lysimeters simulating landfill sites with different plant vegetations. Methane oxidation rates were 35 g methane m−2 day−1 or higher for planted lysimeters and 18 g methane m−2 day−1 or less for bare soil controls. Best methane oxidation, as displayed by gas depth profiles, was found under a vegetation of grass and alfalfa. Methanotroph communities were analysed at high throughput and resolution using a microbial diagnostic microarray targeting the particulate methane monooxygenase (pmoA) gene of methanotrophs and functionally related bacteria. Members of the genera Methylocystis and Methylocaldum were found to be the dominant members in landfill site simulating lysimeters. Soil bacterial communities in biogas free control lysimeters, which were less abundant in methanotrophs, were dominated by Methylocaldum. Type Ia methanotrophs were found only in the top layers of bare soil lysimeters with relatively high oxygen and low methane concentrations. A competetive advantage of type II methanotrophs over type Ia methanotrophs was indicated under all plant covers investigated. Analysis of average and individual results from parallel samples was used to identify general trends and variations in methanotroph community structures in relation to depth, methane supply and plant cover. The applicability of the technology for the detection of environmental perturbations was proven by an erroneous result, where an unexpected community composition detected with the microarray indicated a potential gas leakage in the lysimeter being investigated.
Formation of granules and Methanosaeta fibres in an anaerobic migrating blanket reactor (AMBR)
Authors: Angenent Largus T. , Sung Shihwu , Raskin Lutgarde
Published: March 2004

It has generally been accepted that the formation of granules in anaerobic wastewater treatment systems requires a hydraulic upflow pattern. To evaluate this hypothesis, we operated an anaerobic migrating blanket reactor (AMBR) without a hydraulic upflow pattern, using a synthetic wastewater containing acetate, propionate, butyrate and sucrose. We provided conditions amenable to the formation of granules by operating the system with a moderate hydraulic selection pressure, which in this system was not the result of a hydraulic upflow pattern, but was provided by migration of biomass and intermittent mechanical mixing. Granules were first noticed after 2 months of operation, and it took another 2 months for a mature granular blanket to develop. Besides granules, ≈ 1‐cm‐long Methanosaeta fibres developed and, after 6 months of operation, 30% of biomass consisted of these fibres. Quantitative membrane hybridization showed that almost all the total 16S rRNA extracted from fibres consisted of 16S rRNA from Methanosaeta concilii. This finding indicates that it was possible to develop pockets consisting almost entirely of an organism with a very limited substrate utilization spectrum (only acetate) in a system that was fed a synthetic wastewater containing acetate, propionate, butyrate and sucrose and that is known for its ability to develop biomass with a complex microbial community structure.
Economic Evaluation in Health Care: Is It Really Useful or Are We Just Kidding Ourselves?
Authors: Drummond Michael
Published: March 2004

Despite the growth in published studies year on year, and its adoption as a formal requirement in some jurisdictions, there are still doubts about whether economic evaluation is really useful in health care decision making. This article considers evidence for and against the proposition that economic evaluation is useful. Two decision making contexts are considered: the central level, where a single agency or organisation makes decisions for the whole health care system; and the local level, where decisions are made by various actors within the health care system. Four conditions that seem to foster the use of economic evaluation are identified. It is concluded that economic evaluation is not being used to its full potential, but that ways can be found to increase its use.
Medical Expenditures and Health Status in Australia: A Story of Increasing or Decreasing Returns?
Authors: Connelly Luke B. , Doessel Darrel P.
Published: March 2004

We use a three‐equation model to estimate a health production function for Australia using population data for 1996. Working at the level of the Statistical Local Area (n= 1335) we match (i) data on private practice medical services (derived from the Medicare scheme), (ii) mortality data derived from the de‐identified unit records produced by the Australian Bureau of Statistics (ABS), and (Hi) social and economic data from the Australian Census of Population and Housing (ABS 1997). We detect strong and statistically significant positive marginal effects of medical expenditure on health status as well as increasing returns. These findings are remarkably different from those of US health production studies, which have tended to lend support to the hypothesis of ‘flat‐of‐the‐curve (that is, zero marginal product) medicine’. Moreover, our conclusions are in stark contrast to those produced by Richardson and Peacock (2003, p. 6), who have argued that their econometric work indicates that ‘an increase in the [Australian] doctor supply is associated with increasing mortality’.
Community Antagonism Towards Asylum Seekers in Port Augusta, South Australia
Authors: Klocker Natascha
Published: March 2004

An overtly hostile response to asylum seekers was observed in questionnaire responses provided by residents of Port Augusta, South Australia in April 2002. A social construction approach to identity and representation was used to interrogate this antagonism within its social, cultural, political and geographical contexts. Asylum seekers were constructed as ‘burdensome’, ‘threatening’ and ‘illegal’, and opposition to them was set within the discursive framework of a ‘Self/Other’ binary. Enmity towards asylum seekers was articulated concurrently with overwhelming support for the Federal Government's exclusive and deterrence‐oriented asylum policies. However, vehement opposition was expressed regarding the government's decision to construct Baxter Immigration Reception and Processing Centre in close proximity to Port Augusta. Factors contributing to the respondents’ negative perceptions of asylum seekers include xenophobia (specifically Islamophobia), events of geopolitical significance, and problematic government and media representations of asylum seekers. An awareness of these factors is necessary to unpack and, potentially, to destabilise the negative constructions of asylum seekers circulating in contemporary Australian discourses. Their entrenchment in the national consciousness may lead to tangible social implications including fear, friction and ultimately violence between the ‘Self’ and ‘Other’, and this should therefore be countered. Community antagonism also contradicts notions of a culturally tolerant Australia and fosters electoral support for the policies of exclusion and deterrence that undermine Australia's commitment to international human rights frameworks.

ACRONYMS

ABC The Australian Broadcasting Corporation

ABS The Australian Bureau of Statistics

DIMIA Department of Immigration and Multicultural and Indigenous Affairs

IRPC Immigration Reception and Processing Centre

RCOA Refugee Council of Australia

TPV Temporary Protection Visa

UNHCR The United Nations High Commissioner for Refugees
The Changing Geographies of Power and Control in Rural Service Provision: Recent Restructuring Within the Australian Tractor Dealership System
Authors: Herbert Bronwyn , Pritchard Bill
Published: March 2004

Over the past few years a considerable body of research has illuminated the changing geographies of service provision in rural Australia. Mostly, this work has emphasised the quantitative aspects of restructuring, by way of documenting numerical reductions in service delivery points and their implications for local employment and service access. In this paper, an examination of recent restructuring within the dealership system for high‐horsepower tractors underlines that these quantitative changes also intersect with qualitative shifts to the character of service delivery. Interviews with 31 participants in the tractor dealership system of Central‐West New South Wales reveal the recent evolution of a producer‐driven supply chain in which two dominant, multinational, tractor‐machinery companies have sought to exercise tighter control over customer relations through the restructuring of franchise agreements with dealers. There has been a resultant demise of the independent dealership, and its replacement by a system of standardised, company‐affiliated outlets operated by franchise holders. Hence, the spatial restructuring of this industry represents the surface manifestations of corporate strategies in which large economic entities are re‐organising their interests in light of globalised theatres of competition and profit. In this sense, the tractor‐dealership system is emblematic of changes to power and control in rural service provision as the franchise models propagated by large corporate interests increasingly subsume the small‐business sector activities of Australia's rural towns.
Response to Wet Season Rainfall of an Alluvial Aquifer System in the Lower Herbert Floodplain, Queensland, Australia
Authors: Pearce Meryl W. , Bohl Heiko P.
Published: March 2004

Australia is one of the world's largest exporters of raw sugar. The lower Herbert River floodplain, one of the four main cane growing areas in Queensland, is subject to extremes of rainfall. Some areas are prone to waterlogging, which can lead to reductions in cane and sugar yields. This paper examines the risk of waterlogging and the role of surface drains in the Ripple Creek area, a subcatchment of the lower Herbert River floodplain. Following above‐average rains at the onset of this study, a perched water table developed and remained for the duration of the 19 month study. The responses of the perched watertable and a deeper semi‐confined aquifer following rainfall are examined. The rapid response of the perched water table following rainfall is attributed to the shallow depth of the water table, with soil properties exerting a dominant influence on hydrograph response. In the second year of the study, after above‐average rainfall, the water table of the deeper aquifer was on average 1 m higher than during the former months of the study. This trend, however, did not occur in the perched water table, and this is attributed to the efficiency of the surface drainage network.
A 6000 Year‐old Fossil Dugong from Botany Bay: Inferences about Changes in Sydney's Climate, Sea Levels and Waterways
Authors: Haworth R. J. , Baker R. G. V. , Flood P. J.
Published: March 2004

The excavation in the 1890s of a skeleton of the warm‐water marine mammal Dugong dugon, associated with Aboriginal artefacts, from a Botany Bay salt marsh, marked the beginning of speculation about climate and sea level change in Australia over the period of human occupation. The dugong bones have recently been dated, giving a conventional 14C age of 5520±70 years BP, which is consistent with three older 14C dates for a layer of buried trees that underlies much of the north Botany sediments. The carefully drawn cross‐sections of depositional strata produced by the original discoverers allow further interpretation of the pattern of Holocene sea‐level fluctuations in the Sydney region. Layers of estuarine sediment, such as the one containing the dugong skeleton, are inter‐bedded with peat layers containing in situ roots and stumps, suggesting that the site alternated between sub‐aerial exposure and submergence throughout the Holocene. The presence of the dugong is suggestive of warmer conditions, and its inland location indicates a more extensive Botany Bay in the recent past. This is in agreement with other work from southern New South Wales describing both warm‐water marine species and higher sea levels several thousand years ago.

ACRONYMS

BP Radiocarbon years Before Present (1950 AD).

CalBP Radiocarbon years Before Present calibrated to tree ring data curves to give a better approximation of true calendar dates.
Fishing Lifestyles: ‘Territorians’, Traditional Owners and the Management of Recreational Fishing in Kakadu National Park
Authors: Palmer Lisa
Published: March 2004

The relationships between traditional Aboriginal land owners and other Park users in Kakadu National Park in the Northern Territory are characterised by competing agendas and competing ideas about appropriate ways of relating to the environment. Similarly, the management of recreational fishing in the Park is permeated by the tensions and opposition of contested ideas and perspectives from non‐Aboriginal fishers and Aboriginal traditional owners. The local know‐ledge and rights of ‘Territorians’[non‐Aboriginal Northern Territory residents] are continually pitted against the local knowledge and rights of Aboriginal traditional owners. Under these circumstances, debates between non‐Aboriginal fishers and Aboriginal traditional owners are overwhelmingly dominated by the unequal power relationships created through an alliance between science and the State. The complex and multi‐dimensional nature of Aboriginal traditional owners’ concerns for country renders these concerns invisible or incomprehensible to government, science and non‐Aboriginal fishers who are each guided by very different epistemic commitments. It is a state of affairs that leaves the situated knowledge of Aboriginal traditional owners with a limited authority in the non‐Aboriginal domain and detracts from their ability to manage and care for their homelands.

ACRONYMS

AFANT Amateur Fishermen's Association of the Northern Territory

ALRA Aboriginal Land Rights (Northern Territory) Act 1976 (Cth)

ANCA Australian Nature Conservation Agency

ANPWS Australian National Parks and Wildlife Service

KNPBoM Kakadu National Park Board of Management