Sabina is an academic editor at UTS who specialises in research grant proposals. She supports research development in the Climate Change Cluster (C3) in the Faculty of Science, and across other faculties in the university, as a member of the Research and Innovation Office. Within C3, she edits a variety of academic documents including strategic plans, business cases and capability statements.
Sabina is a former research academic with over 20 years of experience in Life Sciences research, gained at universities in Melbourne, Sydney and Switzerland. She is a recipient of the UNSW Eureka Prize for Scientific Research, and joint winner of the UTS Vice-Chancellor’s Research Excellence Award (Research Support).
Institute of Professional Editors (NSW Branch)
Australian Science Communicators
NSW Writers' Centre.
Katrib, M, Ikin, RJ, Brossier, F, Robinson, M, Slapetova, I, Sharman, PA, Walker, RA, Belli, SI, Tomley, FM & Smith, NC 2012, 'Stage-specific expression of protease genes in the apicomplexan parasite, Eimeria tenella', BMC GENOMICS, vol. 13.View/Download from: Publisher's site
Mai, K, Smith, NC, Feng, Z, Katrib, M, Slapeta, J, Slapetova, I, Wallach, M, Luxford, C, Davies, MJ, Zhang, X, Norton, RS & Belli, SI 2011, 'Peroxidase catalysed cross-linking of an intrinsically unstructured protein via dityrosine bonds in the oocyst wall of the apicomplexan parasite, Eimeria maxima', International Journal For Parasitology, vol. 41, no. 11, pp. 1157-1164.View/Download from: Publisher's site
Apicomplexan parasites such as Eimeria maxima possess a resilient oocyst wall that protects them upon excretion in host faeces and in the outside world, allowing them to survive between hosts. The wall is formed from the contents of specialised organelles - wall-forming bodies - found in macrogametes of the parasites. The presence of dityrosine in the oocyst wall suggests that peroxidase-catalysed dityrosine cross-linking of tyrosine-rich proteins from wall-forming bodies forms a matrix that is a crucial component of oocyst walls. Bioinformatic analyses showed that one of these tyrosine-rich proteins, EmGAM56, is an intrinsically unstructured protein, dominated by random coil (52-70%), with some alpha-helix (28-43%) but a relatively low percentage of beta-sheet (1-11%); this was confirmed by nuclear magnetic resonance and circular dichroism. Furthermore, the structural integrity of EmGAM56 under extreme temperatures and pH indicated its disordered nature. The intrinsic lack of structure in EmGAM56 could facilitate its incorporation into the oocyst wall in two ways: first, intrinsically unstructured proteins are highly susceptible to proteolysis, explaining the several differently-sized oocyst wall proteins derived from EmGAM56; and, second, its flexibility could facilitate cross-linking between these tyrosine-rich derivatives. An in vitro cross-linking assay was developed using a recombinant 42 kDa truncation of EmGAM56. Peroxides, in combination with plant or fungal peroxidases, catalysed the rapid formation of dityrosine cross-linked polymers of the truncated EmGAM56, as determined by western blotting and HPLC, confirming this protein's propensity to form dityrosine bonds.
Belli, SI, Ferguson, DJ, Katrib, M, Slapetova, I, Mai, K, Slapeta, J, Flowers, SA, Miska, KB, Tomley, FM, Shirley, M, Wallach, M & Smith, NC 2009, 'Conservation of proteins involved in oocyst wall formation in Eimeria maxima, Eimeria tenella and Eimeria acervulina', International Journal For Parasitology, vol. 39, no. 10, pp. 1063-1070.View/Download from: Publisher's site
Vaccination with proteins from gametocytes of Eimeria maxima protects chickens, via transfer of maternal antibodies, against infection with several species of Eimeria. Antibodies to E. maxima gametocyte proteins recognise proteins in the wall forming bodies of macrogametocytes and oocyst walls of E. maxima, Eimeria tenella and Eimeria acervulina. Homologous genes for two major gametocyte proteins GAM56 and GAM82 were found in E. maxima, E. tenella and E. acervulina. Alignment of the predicted protein sequences of these genes reveals that, as well as sharing regions of tyrosine richness, strong homology exists in their amino-terminal regions, where protective antibodies bind. This study confirms the conservation of the roles of GAM56 and GAM82 in oocyst wall formation and shows that antibodies to gametocyte antigens of E. maxima cross-react with homologous proteins in other species, helping to explain cross-species maternal immunity.
Mai, K, Sharman, PA, Walker, RA, Katrib, M, De Souza, D, McConville, M, Wallach, M, Belli, SI, Ferguson, DJ & Smith, NC 2009, 'Oocyst wall formation and composition in coccidian parasites', Memorias do Instituto Oswaldo Cruz, vol. 104, no. 2, pp. 281-289.
The oocyst wall of coccidian parasites is a robust structure that is resistant to a variety of environmental and chemical insults. This resilience allows oocysts to survive for long periods, facilitating transmission from host to host. The wall is bilayered and is formed by the sequential release of the contents of two specialized organelles - wall forming body 1 and wall forming body 2 - found in the macrogametocyte stage of Coccidia. The oocyst wall is over 90% protein but few of these proteins have been studied. One group is cysteine-rich and may be presumed to crosslink via disulphide bridges, though this is yet to be investigated. Another group of wall proteins is rich in tyrosine. These proteins, which range in size from 8-31 kDa, are derived from larger precursors of 56 and 82 kDa found in the wall forming bodies. Proteases may catalyze processing of the precursors into tyrosine-rich peptides, which are then oxidatively crosslinked in a reaction catalyzed by peroxidases. In support of this hypothesis, the oocyst wall has high levels of dityrosine bonds. These dityrosine crosslinked proteins may provide a structural matrix for assembly of the oocyst wall and contribute to its resilience.
Jones, M, McManus, DP, Sivadorai, P, Glanfield, A, Moertel, L, Belli, SI & Gobert, G 2007, 'Tracking The Fate Of Iron In Early Development Of Human Blood Flukes', International Journal Of Biochemistry & Cell Biology, vol. 39, no. 9, pp. 1646-1658.View/Download from: Publisher's site
Iron (Fe) is an important trace element found in nearly all organisms, and is used as a cofactor in many biological reactions. One role for Fe in some invertebrates is in stabilization of extracellular matrices. The human blood fluke, Schistosoma japonic
Coccidian parasites are transmitted between hosts by the ingestion of food or water contaminated with oocysts, followed by the release of infectious sporozoites and invasion of the gastro-intestinal tract. In the external environment, sporozoites are pro
Members of the phylum Apicomplexa are important protozoan parasites that cause some of the most serious, and in some cases, deadly diseases in humans and animals. They include species from the genus Plasmodium, Toxoplasma, Eimeria, Neospora, Cryptosporid
Belli, SI, Mai, K, Skene, C, Gleeson, M, Witcombe, DM, Katrib, M, Finger, A, Wallach, M & Smith, NC 2004, 'Characterisation of the antigenic and immunogenetic properties of bacterially expressed, sexual stage antigens of the coccidian parasite, Eimeria maxima', Vaccine, vol. 22, pp. 4316-4325.View/Download from: Publisher's site
Witcombe, DM, Ferguson, DJ, Belli, SI, Wallach, M & Smith, NC 2004, 'Eimeria maxima TRAP family protein EmTFP250: subcellular localisation and induction of immune responses by immunisation with a recombinant C-terminal derivative', International Journal for Parasitology, vol. 34, pp. 861-872.View/Download from: Publisher's site
Belli, SI, Monnerat, S, Schaff, C, Masina, S, Noll, T, Myler, PJ, Stuart, K & Fasel, N 2003, 'Sense and antisense transcripts in the histone (HIS-1) locus of Leishmania major', International Journal of Parasitology, vol. 33, pp. 965-975.View/Download from: Publisher's site
Belli, SI, Wallach, M & Smith, NC 2003, 'Cloning and characterization of the 82 kDa tyrosine-rich sexual stage glycoprotein, GAM82, and its role in oocyst wall formation in the apicomplexan parasite, Eimeria maxima', Gene, vol. 307, pp. 201-212.View/Download from: Publisher's site
Belli, SI, Wallach, M, Luxford, C, Davies, MJ & Smith, NC 2003, 'Roles of tyrosine-rich precursor glycoproteins and dityrosine- and 3,4-dihydroxyphenylalanine-mediated protein cross-linking in development of the oocyst wall in the coccidian parasite Eimeria maxima', Eukaryotic Cell, vol. 2, no. 3, pp. 456-464.View/Download from: Publisher's site
Ferguson, DJ, Belli, SI, Smith, NC & Wallach, M 2003, 'The development of the macrogamete and oocyst wall in Eimeria maxima: immuno-light and electron microscopy', International Journal For Parasitology, vol. 33, no. 12, pp. 1329-1340.View/Download from: Publisher's site
Witcombe, DM, Belli, SI, Wallach, M & Smith, NC 2003, 'Molecular characterisation of EmTFP250: a novel member of the TRAP protein family in Eimeria maxima', International Journal For Parasitology, vol. 33, no. 7, pp. 691-702.View/Download from: Publisher's site
Belli, SI, Bakar, M, Thebo, P, Wallach, M, Schwartsburd, B & Smith, NC 2002, 'Biochemical characterisation of the 56 and 82 kDa immunodominant gametocyte antigens from Eimeria maxima', International Journal for Parasitology, vol. 32, no. N/A, pp. 805-816.
Belli, SI, Witcombe, DM, Wallach, M & Smith, NC 2002, 'Functional genomics of gam56: role of a 56 kilodation sexual stage antigen in oocyst wall formation in Eimeria maxima', International Journal for Parasitology, vol. 32, no. N/A, pp. 1727-1737.View/Download from: Publisher's site
Rafati, S, Salmanian, A, Hashemi, K, Schaff, C, Belli, SI & Fasel, N 2001, 'Identification of the Keishmania major Cysteine proteinases as targets of the Immune Response in humans', Molecular & Biomedical Parasitology, vol. 113, pp. 35-43.
In this study, we report the identification of two parasite polypeptides recognized by human sera of patients infected with Leishmania major. Isolation and sequencing of the two genes encoding these polypeptides revealed that one of the genes is similar to the L. major cathepsin L-like gene family CPB, whereas the other gene codes for the L. major homologue of the cysteine proteinase a (CPA) of L. mexicana. By restriction enzyme digestion of genomic DNA, we show that the CPB gene is present in multiple copies in contrast to the cysteine proteinase CPA gene which could be unique. Specific antibodies directed against the mature regions of both types expressed in Escherichia coli were used to analyze the expression of these polypeptides in different stages of the parasites life cycle. Polypeptides of 27 and 40 kDa in size, corresponding to CPA and CPB respectively, were detected at higher level in amastigotes than in stationary phase promastigotes. Purified recombinant CPs were also used to examine the presence of specific antibodies in sera from either recovered or active cases of cutaneous leishmaniasis patients. Unlike sera from healthy uninfected controls, all the sera reacted with recombinant CPA and CPB. This finding indicates that individuals having recovered from cutaneous leishmaniasis or with clinically apparent disease have humoral responses to cysteine proteinases demonstrating the importance of these proteinases as targets of the immune response and also their potential use for serodiagnosis.
Belli, SI 2000, 'Chromatin Remodelling During the Life Cycle of Trypanosomatids', International Journal for Parasitology, vol. 30, no. 0, pp. 679-687.
The mechanisms which control the expression of developmentally regulated genes in trypanosomatids remain unclear. The genes are grouped together into transcription units that are co-transcribed to yield polycistronic RNAs. Trans-splicing and polyadenylation give rise to mature, monocistronic mRNAs. It is difficult to imagine that expression of these genes is controlled at the level of transcription initiation because this would suggest that the genes are transcribed at the same rate. This is not the case, because at any given developmental stage in trypanosomes or Leishmania, genes transcribed from the same transcription unit are expressed at different levels within the cell. Consequently, these parasites must rely on post-transcriptional or post-translational mechanisms to generate the appropriate levels of gene product within the cell. There are no well-established examples of RNA polymerase II promoters in trypanosomes or Leishmania. However, the promoters for genes encoding the variant surface glycoprotein (VSG) and the procyclic acidic repetitive protein (PARP) have been identified and resemble ribosomal RNA polymerase I promoters. In higher eukaryotes where the mechanisms regulating transcription are clearer, there is increasing evidence that epigenetic factors, such as histones and modified bases, influence gene expression. Chemical modification of these factors can restructure chromatin and lead to gene activation or silencing. In trypanosomatids, an epigenetic mechanism for the control of developmentally expressed genes is a possibility. In this review, chromatin remodelling during the life and cell cycle of trypanosomes and Leishmania is explored, and the influence of epigenetic factors such as histones and modified bases on this process is discussed.
Belli, S, Formenton, A, Noll, T, Ivens, A, Jacquet, R, Desponds, C, Hofer, D & Fasel, N 1999, 'Leishmania major: Histone H1 gene expression from the sw3 locus', EXPERIMENTAL PARASITOLOGY, vol. 91, no. 2, pp. 151-160.View/Download from: Publisher's site
Bastien, P, Blaineau, C, Britto, C, Dedet, JP, Dubessay, P, Pages, M, Ravel, C, Wincker, P, Blackwell, JM, Leech, V, Levick, M, Norrish, A, Ivens, A, Lewis, S, Bagherzadeh, A, Smith, D, Myler, P, Stuart, K, Cruz, A, Ruiz, JC, Schneider, H, Sampaio, I, Almeida, R, Papadopoulou, B, Shapira, M, Belli, S & Fasel, N 1998, 'The complete chromosomal organization of the reference strain of the Leishmania genome project, L. major 'Friedlin'', Parasitology Today, vol. 14, no. 8, pp. 301-303.View/Download from: Publisher's site
Clayton, C, Adams, M, Almeida, R, Baltz, T, Barrett, M, Bastien, P, Belli, S, Beverley, S, Biteau, N, Blackwell, J, Blaineau, C, Boshart, M, Bringaud, F, Cross, G, Cruz, A, Degrave, W, Donelson, J, El-Sayed, N, Fu, GL, Ersfeld, K, Gibson, W, Gull, K, Ivens, A, Kelly, J, Lawson, D, Lebowitz, J, Majiwa, P, Matthews, K, Melville, S, Merlin, G, Michels, P, Myler, P, Norrish, A, Opperdoes, F, Papadopoulou, B, Parsons, M, Seebeck, T, Smith, D, Stuart, K, Turner, M, Ullu, E & Vanhamme, L 1998, 'Genetic nomenclature for Trypanosoma and Leishmania', MOLECULAR AND BIOCHEMICAL PARASITOLOGY, vol. 97, no. 1-2, pp. 221-224.View/Download from: Publisher's site
Goding, J, Terkeltaub, R, Maurice, M, Deterre, P, Sali, A & Belli, SI 1998, 'Ecto-phosphodiesteraseperpyrophosphatase Of Lymphocytes And Non-lymphoid Cells: Structure And Function Of The Pc-1 Family', Immunological Reviews, vol. 161, pp. 11-26.View/Download from: Publisher's site
Many developmentally regulated membrane proteins of lymphocytes are ecto-enzymes, with their active sites on the external surface of the cell. These enzymes commonly have peptidase, phosphodiesterase or nucleotidase activity. Their biological roles are j
Noll, T, Desponds, C, Belli, SI, Glaser, T & Fasel, N 1997, 'Histone H1 Expression Varies During The Leishmania Major Life Cycle', Molecular And Biochemical Parasitology, vol. 84, no. 2, pp. 215-227.View/Download from: Publisher's site
The deduced amino acid sequence of Leishmania major sw3 cDNA reveals the presence of characteristic histone H1 amino acid motifs. However, the open reading frame is of an unusually small size for histone H1 (105 amino acids) because it lacks the coding p
Belli, SI, Mercuri, F, Sali, A & Goding, J 1995, 'Autophosphorylation Of Pc-1 (alkaline Phosphodiesterase-i Nucleotide Pyrophosphatase) And Analysis Of The Active-site', European Journal Of Biochemistry, vol. 228, no. 3, pp. 669-676.View/Download from: Publisher's site
PC-1 is an ecto-enzyme possessing alkaline phosphodiesterase I (EC 188.8.131.52) and nucleotide pyrophosphatase (EC 184.108.40.206) activities. It has also been proposed to be an ecto-protein kinase capable of phosphorylating itself as well as exogenous proteins. We
Belli, SI, Mercuri, FA, Sali, A & Goding, JW 1995, 'Autophosphorylation of PC-1 (Alkaline Phosphodiesterase I/Nucleotide Pyrophosphatase) and Analysis of the Active Site', European Journal of Biochemistry, vol. 228, no. 3, pp. 669-676.View/Download from: Publisher's site
Belli, SI, Mercuri, FA, Sali, A & Goding, JW 1995, 'Autophosphorylation of PC‐1 (Alkaline Phosphodiesterase I/Nucleotide Pyrophosphatase) and Analysis of the Active Site', European Journal of Biochemistry, vol. 228, no. 3, pp. 669-676.View/Download from: Publisher's site
PC‐1 is an ecto‐enzyme possessing alkaline phosphodiesterase I (EC 220.127.116.11) and nucleotide pyrophosphatase (EC 18.104.22.168) activities. It has also been proposed to be an ecto‐protein kinase capable of phosphorylating itself as well as exogenous proteins. We have investigated the phosphorylation capability of PC‐1 and have developed a novel method for its detection and characterization based on autophosphorylation, which allows detection without the use of antibodies. When cells expressing membrane PC‐1 were held on ice with [γ‐32P]ATP, SDS/PAGE of whole cell lysates showed a single band which was PC‐1; this band was absent in cells not expressing PC‐1. Immunoprecipitates of soluble PC‐1 isolated from culture supernatants of cells expressing PC‐1 were also capable of autophosphorylation, and the size of the labeled protein was the same as previously reported for soluble PC‐1. PC‐1 was also labeled with [γ‐32P]ATP and [α‐35S]dATP[αS]. We found no evidence that PC‐1 was capable of phosphorylating proteins other than itself, and conclude that it is not a true kinase, and that the observed labeling with [γ‐32P]ATP, [α‐32P]ATP and [35S]dATP[αS] reflect transient covalent adducts that are part of the catalytic cycle of phosphodiesterase/pyrophosphatase activity rather than intrinsic kinase activity. Mutation of the active‐site threonine to tyrosine, serine or alanine reduced the 5'‐nucleotide phosphodiesterase activity of PC‐1 and its ability to autophosphorylate to undetectable levels. Together, these data suggest that both activities depend on the same site. Copyright © 1995, Wiley Blackwell. All rights reserved
Belli, SI & Goding, J 1994, 'Biochemical-characterization Of Human Pc-1, An Enzyme Possessing Alkaline Phosphodiesterase-i And Nucleotide Pyrophosphatase Activities', European Journal Of Biochemistry, vol. 226, no. 2, pp. 433-443.View/Download from: Publisher's site
PC-1 is an ecto-enzyme possessing alkaline phosphodiesterase I and nucleotide pyrophosphatase activities. In this paper, we demonstrate the expression, biochemical characterization and biosynthesis of human PC-1. Previously, there has been uncertainty co
Belli, SI, Sali, A & Goding, J 1994, 'Divalent-cations Stabilize The Conformation Of Plasma-cell Membrane Glycoprotein Pg-1 (alkaline Phosphodiesterase-i)', Biochemical Journal, vol. 304, pp. 75-80.
The plasma cell-membrane glycoprotein PC-1 is an ectoenzyme with alkaline phosphodiesterase Iper5-nucleotide phosphodiesterase (EC 22.214.171.124) and nucleotide pyrophosphatase (EC 126.96.36.199) activities. It contains sequence motifs which closely match the consen
Belli, SI, Vandriel, I & Goding, J 1993, 'Identification And Characterization Of A Soluble Form Of The Plasma-cell Membrane Glycoprotein Pc-1 (5-nucleotide Phosphodiesterase)', European Journal Of Biochemistry, vol. 217, no. 1, pp. 421-428.View/Download from: Publisher's site
PC-1 is a membrane glycoprotein, found on the surface of plasma cells and a few types of non-lymphoid cells, which has recently been found to have 5-nucleotide phosphodiesterase activity. In this paper, we demonstrate the existence of enzymically active