Showing papers by "Enzo A. Palombo published in 2012"

Molecular Characterisation of Gastrointestinal Microbiota of Children With Autism (With and Without Gastrointestinal Dysfunction) and Their Neurotypical Siblings

Abstract: Many children with autism spectrum disorders (ASDs) suffer from gastrointestinal problems such as diarrhoea, constipation and abdominal pain. This has stimulated investigations into possible abnormalities of intestinal microbiota in autistic patients. Therefore, we designed this study to identify differences (and/or similarities) in the microbiota of children with autism (without gastrointestinal dysfunction: n = 23; with gastrointestinal dysfunction: n = 28) and their neurotypical siblings (n = 53) who share a similar environment using bacterial tag-encoded FLX amplicon pyrosequencing. Regardless of the diagnosis and sociodemographic characteristics, overall, Firmicutes (70%), Bacteroidetes (20%) and Proteobacteria (4%) were the most dominant phyla in samples. Results did not indicate clinically meaningful differences between groups. The data do not support the hypothesis that the gastrointestinal microbiota of children with ASD plays a role in the symptomatology of ASD. Other explanations for the gastrointestinal dysfunction in this population should be considered including elevated anxiety and self-restricted diets.

Enzyme inhibitory and antioxidant activities of traditional medicinal plants: potential application in the management of hyperglycemia.

Abstract: Traditional Indian and Australian medicinal plant extracts were investigated to determine their therapeutic potential to inhibit key enzymes in carbohydrate metabolism, which has relevance to the management of hyperglycemia and type 2 diabetes. The antioxidant activities were also assessed. The evaluation of enzyme inhibitory activity of seven Australian aboriginal medicinal plants and five Indian Ayurvedic plants was carried out against α-amylase and α-glucosidase. Antioxidant activity was determined by measuring (i) the scavenging effect of plant extracts against 2, 2-diphenyl-1-picryl hydrazyl (DPPH) and 2, 2′-azinobis-3-ethylbenzothiazoline-6-sulfonate (ABTS) and (ii) ferric reducing power. Total phenolic and total flavonoid contents were also determined. Of the twelve plant extracts evaluated, the highest inhibitory activity against both α-amylase and α-glucosidase enzymes was exerted by Santalum spicatum and Pterocarpus marsupium with IC50 values of 5.43 μg/ml and 0.9 μg/ml, respectively, and 5.16 μg/ml and 1.06 μg/ml, respectively. However, the extracts of Acacia ligulata (IC50 = 1.01 μg/ml), Beyeria leshnaultii (0.39 μg/ml), Mucuna pruriens (0.8 μg/ml) and Boerhaavia diffusa (1.72 μg/ml) exhibited considerable activity against α-glucosidase enzyme only. The free radical scavenging activity was found to be prominent in extracts of Acacia kempeana, Acacia ligulata followed by Euphorbia drummondii against both DPPH and ABTS. The reducing power was more pronounced in Euphorbia drummondii and Pterocarpus marsupium extracts. The phenolic and flavonoid contents ranged from 0.42 to 30.27 μg/mg equivalent of gallic acid and 0.51 to 32.94 μg/mg equivalent of quercetin, respectively, in all plant extracts. Pearson’s correlation coefficient between total flavonoids and total phenolics was 0.796. The results obtained in this study showed that most of the plant extracts have good potential for the management of hyperglycemia, diabetes and the related condition of oxidative stress.

Pharmacological properties of guggulsterones, the major active components of gum guggul.

Abstract: Oleo gum resin secreted by Commiphora mukul, also known as gum guggul, has been used widely as an ayurvedic drug. Commiphora mukul is a short thorny shrub that is native to the Indian subcontinent. Oleo gum resin extracted by incision of the bark is a very complex mixture of gum, minerals, essential oils, terpenes, sterols, ferrulates, flavanones and sterones. Its active constituents, the Z- and E-guggulsterones, have been demonstrated to exhibit their biological activities by binding to nuclear receptors and modulating the expression of proteins involved in carcinogenic activities. Guggulsterones have also been reported to regulate gene expression by exhibiting control over other molecular targets including transcription factors such as nuclear factor (NF)-κB, signal transducer and activator of transcription (STAT) and steroid receptors. Considerable scientific evidence indicates the use of gum guggul as a therapeutic agent in the treatment of inflammation, nervous disorders, hyperlipidaemia and associated cardiac disorders such as hypertension and ischaemia, skin disorders, cancer and urinary disorders. This review highlights the taxonomic details, phytochemical properties and pharmacological profile of gum guggul.

Identification of a copper-responsive promoter and development of a copper biosensor in the soil bacterium Achromobacter sp. AO22

Abstract: A number of human activities result in environmental contamination with copper compounds that can cause severe detrimental effects on the ecosystem as well as human health. The physico-chemical methods of metal detection have limitations such as inability to distinguish between total versus bio-available metals and differences in metal uptake in different organisms. The heavy metal resistance-encoding genetic systems of certain bacteria provide critical tools for development of biosensors for these purposes. This study reports a copper biosensor utilizing the cop operon of the heavy metal resistant bacterial isolate, Achromobacter sp. AO22, isolated from a contaminated site in Australia. A section located between the divergently transcribed putative response regulator gene copR and multicopper oxidase gene copA that included a palindromic cop box was identified as a copper-responsive promoter using a lacZ reporter construct, pCOPRP, in E. coli. The expression was found to be enhanced by inclusion of copR. Another engineered strain, AO22(pCOPRP), showed stronger induction, and the lacZ expression in both backgrounds was enhanced significantly (250–400 fold) by copper but minimally by other metals. The construct in Achromobacter sp. AO22 thus has a high potential as biosensor for detecting copper bioavailability (hence potential toxicity) in a soil bacterial background, while the construct in E. coli is ideal for laboratory-based testing.

The heavy metal tolerant soil bacterium Achromobacter sp. AO22 contains a unique copper homeostasis locus and two mer operons.

Abstract: Copper-containing compounds are introduced into the environment through agricultural chemicals, mining, and metal industries and cause severe detrimental effects on ecosystems. Certain microorganisms exposed to these stressors exhibit molecular mechanisms to maintain intracellular copper homeostasis and avoid toxicity. We have previously reported that the soil bacterial isolate Achromobacter sp. AO22 is multi-heavy metal tolerant and exhibits a mer operon associated with a Tn21 type transposon. The present study reports that AO22 also hosts a unique cop locus encoding copper homeostasis determinants. The putative cop genes were amplified from the strain AO22 using degenerate primers based on reported cop and pco sequences, and a constructed 10,552 base pair contig (GenBank Accession No. GU929214). BLAST analyses of the sequence revealed a unique cop locus of 10 complete open reading frames, designated copSRABGOFCDK, with unusual separation of copCD from copAB. The promoter areas exhibit two putative cop boxes, and copRS appear to be transcribed divergently from other genes. The putative protein CopA may be a copper oxidase involved in export to the periplasm, CopB is likely extracytoplasmic, CopC may be periplasmic, CopD is cytoplasmic/inner membrane, CopF is a P-type ATPase, and CopG, CopO, and CopK are likely copper chaperones. CopA, B, C, and D exhibit several potential copper ligands and CopS and CopR exhibit features of two-component regulatory systems. Sequences flanking indicate the AO22 cop locus may be present within a genomic island. Achromobacter sp. strain AO22 is thus an ideal candidate for understanding copper homeostasis mechanisms and exploiting them for copper biosensor or biosorption systems.

Endophytes from medicinal plants as novel sources of bioactive compounds

Abstract: The threat posed by diseases such as cancers and infections is everincreasing. Challenges to public health and well-being include the development of drug-resistant microbes and life threatening viruses, and the problems caused by loss of biodiversity and the degradation of natural resources as a result of toxic organic insecticides and industrial effl uent. Therefore, there is a general need for new and useful bioactive compounds, which are highly effective, possess low toxicity and have minor environmental impact. Traditionally, such compounds (commonly referred to as “natural products”) have come from the natural environment, such as microorganisms, plants and invertebrates. However, a recent trend has been to screen libraries of synthetic chemicals for bioactivity. Although this approach has brought some success, the general consensus is that outcomes have been generally disappointing. Therefore, interest is once again turning to natural products for the discovery of new drugs and chemical compounds. Without doubt, natural products have been the single most productive source for the development of new drugs, 1Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, PO Box 218, Hawthorn VIC 3122, Australia. aE-mail: bzaferanloo@swin.edu.au bE-mail: pmahon@swin.edu.au cE-mail: epalombo@swin.edu.au *Corresponding authorparticularly anti-cancer and anti-infective agents. While plants have been a great source of valuable bioactive compounds, attention has recently turned to endophytes-microorganisms (fungi and bacteria) living in the intercellular spaces of plant tissues without causing any obvious harmwhich are recognized as potential sources of novel secondary metabolites with potential application in medicine, agriculture and industry (Bacon and White 2000). It is noteworthy that each of the approximately 300,000 plant species which exist on our planet is host to one or more endophytes (Strobel and Daisy 2003). In addition, it is estimated that there may be as many as one million different fungal species, of which only a handful have been studied in detail (Ganley et al. 2004). Endophytes synthesize an enormous range of bioactive compounds (Owen and Hundley 2004), thus there is a great opportunity to fi nd new natural products from interesting endophytic microorganisms among the myriad of plants in different niches and ecosystems.

Wheat grain hardness: multigenic basis and its implications: Abstracts

Abstract: The grain hardness (or texture) of common wheat (Triticum aestivum L.) is an important measure of grain quality and significantly influences the end-use of wheat and its commercial value. The two puroindoline genes, Pina-D1 and Pinb-D1, located at the Ha locus on chromosome 5D only of common wheat, are key genetic determinants of grain hardness. These encode small molecular weight (∼13 kDa) proteins called puroindoline A and B (PINA and PINB), respectively, which are lipid-binding proteins with a distinct 10-cysteine backbone, a helicoid structure and a unique tryptophan-rich domain (TRD). When both PINs are in wild-type, they are proposed to lead to soft grain texture, while diverse mutations in either/both genes have been associated with grain hardness of common wheat and deletion of Pin genes in both genomes associated with the very hard texture of durum (reviewed in Bhave & Morris, 2008).The recently reported Pinb-2 gene on chromosome 7 of common and durum wheat may also have a role in texture (Wilkinson et al., 2008; Chen et al., 2010). We aimed to analyse the Pinb-2 gene diversity in a number of Chinese land races as China is the secondary centre of origin of wheat. The alleles of Pina-D1 and Pinb-D1 were also analysed to get a complete Pin genotype, and durum wheats were included to test their Pinb2 genotypes. Synthetic peptides designed on the PINB-2 TRD were also tested for any antimicrobial activity. The genes were amplified from genomic DNAs using degenerate primers to allow amplification of variants, the PCR products cloned, and a number of clones sequenced to identify individual sequences. The Pinb-2 genes were identified in all wheats tested and comprised a small family with variations in the putative proteins. A new Pina-D1 allele, Pina-D1t, with a tryptophan-to-stop codon mutation, was also identified. Taken together, the results suggest that the final texture of common wheat could be determined by three interactors: the PINA and PINB (in wild type or altered/null forms) and PINB2 variants, while the texture of durums could be influenced by PINB2 variants. In addition, the PINB2-based peptides exhibited antimicrobial activity, as we noted for PINA and PINB-based peptides, suggesting likely seed defence roles for the whole PIN family.

Comparison of the corrosion of carbon steel in natural seawaters - evidence of mic?

Abstract: SUMMARY: The corrosion behaviour of carbon steel was investigated in natural seawater sampled from two different locations to determine the potential of microbiologically influenced corrosion (MIC) in these waters. Laboratory-based immersion test have been undertaken with 1020 carbon steel in seawater from Port Melbourne and Queenscliff (Victoria). Evidence of accelerated low water corrosion (ALWC), which is related to MIC, has previously been reported for sheet piling in the Queenscliff area. A range of metallurgical, chemical and microbiological measurements have been performed on the test samples including weight loss, 3D optical surface profilometry, scanning electron microscopy, energy dispersive X-ray mapping and MALDI–TOF analysis. While the results of some individual tests, including differences observed between metal coupons tested in the two seawater samples and differences between replicate samples, could potentially be linked to MIC the overall conclusion is that the corrosion observed could not be reliably assigned to MIC.