Project description:Trypanosoma brucei are protozoan parasites that cause sleeping sickness in humans and nagana in cattle. Inside the mammalian host, a quorum sensing-like mechanism coordinates its differentiation from a slender replicative form into a quiescent stumpy form, limiting growth and virulence. SUMOylation is a reversible post-translational modification that enables dynamic regulation of cellular metabolism by the attachment of SUMO monomer or SUMO polymeric chains. We have found that parasites able to conjugate only SUMO monomers are primed for differentiation. This was demonstrated for monomorphic lines that are normally unable to produce stumpy forms in response to quorum sensing signaling in mice, and also for pleomorphic cell lines in which stumpy cells were observed at unusually low parasitemia levels. SUMO chain mutants showed a stumpy compatible transcriptional profile and better competence to differentiate into procyclics. Our study indicates that SUMO depolymerization may represent a coordinated signal triggered during stumpy activation program.
Project description:Background: Resistance to trastuzumab remains a common challenge to HER-2 positive breast cancer. Up until now, the underlying mechanism of trastuzumab resistance is still unclear. tRNA-derived small non-coding RNAs (tDRs), a new class of small non-coding RNA (sncRNAs), have been observed to play an important role in cancer progression. However, the relationship between tDRs and trastuzumab resistance is still unknown. Methods: We detected the levels of tDRs expression in normal breast epithelial cell lines, trastuzumab-sensitive and -resistant breast cancer cell lines using high-throughput sequencing. qRT-PCR was conducted to validate the differentially expressed tDRs in serums from trastuzumab-sensitive and -resistant patients. A receiver operating characteristic (ROC) curve analysis was performed to evaluate the power of specific tDRs. Progression-free survival (PFS) was analyzed using Cox-regression. Furthermore, Gene Ontology (GO) and pathway analyses indicated the potential mechanism underlying tDR-mediated trastuzumab resistance. Results: Our sequence results showed that tDRs were differentially expressed in the HBL-100, SKBR3, and JIMT-1 cell lines. tDR-1960 and tDR-1969 were found significantly upregulated in trastuzumab-resistant patients compared to sensitive individuals, and the ROC analysis showed that tDR-1960 and tDR-1969 were correlated with trastuzumab resistance. In a multivariate analysis, higher levels of tDR-1960 and tDR-1969 expression were associated with significantly shorter PFS in patients with metastatic HER-2 positive breast cancer. Additionally, the GO analysis indicated that tDR-1960 and tDR-1969 were mainly involved in the cellular response to drug, which may partially explain the molecular mechanism underlying trastuzumab resistance in HER-2 positive breast cancer. Conclusion: we comprehensively analyzed tDRs in trastuzumab-sensitive and -resistant breast cancer. Our results suggest that tDR-1960 and tDR-1969 play important roles in trastuzumab resistance. Patients with high levels of tDR-1960 and tDR-1969 expression benefitted less from trastuzumab-based therapy than those that express lower-levels of these tDRs. tDR-1960 and tDR-1969 may be potential biomarkers and intervention targets in the clinical treatment of trastuzumab-resistant breast cancer.
Project description:mRNA expression profiles of trypanosomes from two discrete bloodstream form stages of the parasite (slender and stumpy forms), as well as during the transition of the stumpy population to the procyclic life-cycle stage were studied. Our analysis represents the first comparison of in vivo derived pleomorphic slender cells with genetically identical stumpy forms, and a first analysis of the dynamic changes in mRNA profile that accompany the transition to procyclic forms.
Project description:mRNA expression profiles of trypanosomes from two discrete bloodstream form stages of the parasite (slender and stumpy forms), as well as during the transition of the stumpy population to the procyclic life-cycle stage were studied. Our analysis represents the first comparison of in vivo derived pleomorphic slender cells with genetically identical stumpy forms, and a first analysis of the dynamic changes in mRNA profile that accompany the transition to procyclic forms. Twenty nine RNA samples were generated (5 biological replicates of Stumpy (0h), 1h, 6h, 18h and 48h, and 4 biological replicates of slender forms. Four arrays failed QC.
Project description:Comparative analysis of transcriptome profiles of G. arboreum L. cv. and its fuzzy-lintless mutant (ANOI 1960) at 0 and 10 dpa. Cotton is one of the most commercially important fibre crops in the world and used as a source for natural textile fibre and cottonseed oil. The fuzzy-lintless ovules of cotton mutants are ideal source for identifying genes involved in fibre development by comparing with fibre bearing ovules of wild-type. To decipher molecular mechanisms involved in fibre cell development, transcriptome analysis has been carried out by comparing G. arboreum cv. (wild-type) with its fuzzy-lintless mutant (ANOI 1960). Fuzzed-lintless mutant line was generated by back cross breeding between FL and Fl (recurrent parent) lines (personal communication by Dr. I. S. Katageri). Basically Fibre less type was a RIL, first recovered from cross between G.arboreum (linted) and G. anomalum (lint less). This RIL was used as donor parent and crossed with normal arboreum (as recurrent parent) to develop G. arboreum FL and G. arboreum Fl isogenic lines. This G. arboreum Fl line is named as ANOI 1960. Cotton bolls were collected at fibre initiation (0 dpa/days post anthesis) and elongation (10 dpa) and gene expression profiles were analyzed in wild-type and ANOI 1960 mutant using Affymetrix cotton GeneChip Genome array.
Project description:The gene expression of Trypanosoma brucei has been examined extensively in the blood of mammalian hosts and in forms found in the midgut of its arthropod vector, the tsetse fly. However, trypanosomes also undergo development within the mammalian bloodstream as they progress from morphologically ‘slender forms’ to transmissible ‘stumpy forms’ through morphological intermediates. This transition is temporally progressive within the first wave of parasitaemia such that gene expression can be monitored in relatively pure slender and stumpy populations as well as during the progression between these extremes. The development also represents the progression of cells from translationally active forms adapted for proliferation in the host to translationally quiescent forms, adapted for transmission. We have used metabolic labelling to quantitate translational activity in slender forms, stumpy forms and in forms undergoing early differentiation to procyclic forms in vitro. Thereafter we have examined the cohort of total mRNAs that are enriched in throughout development in the mammalian bloodstream (slender, intermediate and stumpy forms), irrespective of strain, revealing those that exhibit consistent developmental regulation rather than sample specific changes. Transcripts that cosediment with polysomes in stumpy forms and slender forms have also been identified to enrich transcripts that escape translational repression prior to transmission. Combined, the expression and polysomal association of transcripts as trypanosomes undergo development in the mammalian bloodstream haves been defined, providing a resource for trypanosome researchers. This facilitates the identification of those that undergo developmental regulation in the bloodstream and therefore those likely to have a role in the survival and capacity for transmission of stumpy forms.
Project description:Sea snakes propel themselves by lateral deformation waves moving backwards along their bodies faster than they swim. In contrast to typical anguilliform swimmers, however, their swimming is characterized by exaggerated torsional waves that lead the lateral ones. The effect of torsional waves on hydrodynamic forces generated by an anguilliform swimmer is the subject matter of this study. The forces, and the power needed to sustain them, are found analytically using the framework of the slender (elongated) body theory. It is shown that combinations of torsional waves and angle of attack can generate both thrust and lift, whereas combinations of torsional and lateral waves can generate lift of the same magnitude as thrust. Generation of lift comes at a price of increasing tail amplitude, but otherwise carries practically no energetic penalty.