Patterns of genome evolution among the microsporidian parasites Encephalitozoon cuniculi, Antonospora locustae and Enterocytozoon bieneusi

Background

Microsporidia are intracellular parasites that are highly-derived relatives of fungi. They have compacted genomes and, despite a high rate of sequence evolution, distantly related species can share high levels of gene order conservation. To date, only two species have been analysed in detail, and data from one of these largely consists of short genomic fragments. It is therefore difficult to determine how conservation has been maintained through microsporidian evolution, and impossible to identify whether certain regions are more prone to genomic stasis.

Principal Findings

Here, we analyse three large fragments of the Enterocytozoon bieneusi genome (in total 429 kbp), a species of medical significance. A total of 296 ORFs were identified, annotated and their context compared with Encephalitozoon cuniculi and Antonospora locustae. Overall, a high degree of conservation was found between all three species, and interestingly the level of conservation was similar in all three pairwise comparisons, despite the fact that A. locustae is more distantly related to E. cuniculi and E. bieneusi than either are to each other.

Conclusions/Significance

Any two genes that are found together in any pair of genomes are more likely to be conserved in the third genome as well, suggesting that a core of genes tends to be conserved across the entire group. The mechanisms of rearrangments identified among microsporidian genomes were consistent with a very slow evolution of their architecture, as opposed to the very rapid sequence evolution reported for these parasites.     

New Technologies to Prolong Life-time of Peptide and Protein Drugs In vivo

Most peptide and protein drugs are short-lived species in vivo with a circulatory half-life of several minutes. This is particularly valid for non-glycosylated proteins with a molecular mass of less than 50 kDa. Since peptide/protein drugs are not absorbed orally, prolonged maintenance of therapeutically active drugs in the circulatory system is of primary clinical importance. Another major obstacle of injected polypeptide drugs is the elevated concentration of 100–1000 times above the therapeutical level that may be present in the circulatory system shortly after administration. Such overdosing may lead to undesirable side effects such as over-stimulation or down-regulation of receptor sites. In this review we describe two new strategies that overcome these two problems of systemically injected peptide/protein drugs. The first strategy includes Fmoc and FMS derivatization of peptides, proteins and low molecular-weight drugs, converting them to inactive prodrugs that undergo reactivation with desirable pharmacokinetic patterns in body fluids. Based on this Fmoc/FMS-technology, we have developed a second strategy, reversible pegylation. Inactive pegylated peptide/protein drugs release the native active parental molecule at slow rates, and in homogeneous fashion under physiological conditions, thus facilitating prolonged therapeutic effects, following a single administration.     

Proteomic patterns for classification of ovarian cancer and CTCL serum samples utilizing peak pairs indicative of post-translational modifications

Proteomic patterns as a potential diagnostic technology has been well established for several cancer conditions and other diseases. The use of machine learning techniques such as decision trees, neural networks, genetic algorithms, and other methods has been the basis for pattern determination. Cancer is known to involve signaling pathways that are regulated through PTM of proteins. These modifications are also detectable with high confidence using high-resolution MS. We generated data using a prOTOF mass spectrometer on two sets of patient samples: ovarian cancer and cutaneous t-cell lymphoma (CTCL) with matched normal samples for each disease. Using the knowledge of mass shifts caused by common modifications, we built models using peak pairs and compared this to a conventional technique using individual peaks. The results for each disease showed that a small number of peak pairs gave classification equal to or better than the conventional technique that used multiple individual peaks. This simple peak picking technique could be used to guide identification of important peak pairs involved in the disease process.     

High-resolution habitat and bathymetry maps for 65,000 sq. km of Earth’s remotest coral reefs

Coral Reefs - With compelling evidence that half the world’s coral reefs have been lost over the last four decades, there is urgent motivation to understand where reefs are located and their...     

Myocardial remodeling after discrete radiofrequency injury: effects of tissue inhibitor of matrix metalloproteinase-1 gene deletion

Discrete myocardial lesions created through the delivery of radiofrequency (RF) energy can expand; however, the mechanisms have not been established. Matrix metalloproteinases (MMPs) play an important role in myocardial remodeling, and MMP activity can be regulated by the tissue inhibitors of the metalloproteinases (TIMPs). This study examined the role of TIMP-1 in postinjury myocardial remodeling. Lesions were created on the left ventricular (LV) epicardium of wild-type (WT, 8-12 wk, 129SVE) and age-matched TIMP-1 gene-deficient (timp-1(-/-)) mice through the delivery of RF current (80 degrees C, 30 s). Heart mass, LV scar volumes, and collagen content were measured at 1 h and 3, 7, and 28 days postinjury (n = 10 each). Age-matched, nonablated mice were used as reference controls (n = 5). Heart mass indexed to tibial length increased in WT and timp-1(-/-) mice but was greater in the timp-1(-/-) mice by 7 days. Scar volumes increased in a time-dependent manner in both groups but were higher in the timp-1(-/-) mice than the WT mice at 7 days (1.48 +/- 0.09 vs. 1.20 +/- 0.11 mm(3).mg(-1).mm, P < 0.05) and remained higher at 28 days. In the remote myocardium, wall thickness was greater and relative collagen content was lower in the timp-1(-/-) mice at 28 days postinjury. Discrete myocardial RF lesions expand in a time-dependent manner associated with myocyte hypertrophy remote to the scar. Moreover, postinjury myocardial remodeling was more extensive with TIMP-1 gene deletion. Thus TIMP-1 either directly or through modulation of MMP activity may regulate myocardial remodeling following infliction of a discrete injury.     

Synthesis and activity of 1-aryl-1'-imidazolyl methyl ethers as non-thiol farnesyltransferase inhibitors

A series of imidazole-containing methyl ethers (4-5) have been designed and synthesized as potent and selective farnesyltransferase inhibitors (FTIs) by transposition of the D-ring to the methyl group on the imidazole of the previously reported FTIs 3. Several compounds such as 4h and 5b demonstrate superior enzymatic activity to the current benchmark compound tipifarnib (1) with IC(50) values in the lower subnanomolar range, while maintaining excellent cellular activity comparable to tipifarnib. The compounds are characterized as being simple, easier to make, and possess no chiral center involved.     

Design, synthesis, and activity of 4-quinolone and pyridone compounds as nonthiol-containing farnesyltransferase inhibitors

As a part of our efforts to identify potent inhibitors of farnesyltransferase (FTase), modification of the structure of tipifarnib through structure-based design was undertaken by replacing the 2-quinolones with 4-quinolones and pyridones, and subsequent relocation of the D-ring to the N-methyl group on the imidazole ring. This study has yielded a novel series of potent and selective FTase inhibitors. The X-ray structure of tipifarnib (1) in complex with FTase was described.