Germinal angiotensin I-converting enzyme is totally shed from the rodent sperm membrane during epididymal maturation

Acquisition of sperm fertilizing ability is due, in part, to the reorganization of plasma membrane proteins that occurs during epididymal sperm transit. Using polyclonal antibodies against angiotensin I-converting enzyme (ACE), we showed that this enzyme is immunolocalized mainly on the middle piece of rat and mouse testicular sperm and with less intensity along the initial part of the principal piece of the flagellum. In both species, only some sperm from the caput epididymis were still reactive, whereas no labeling was observed on cauda epididymal sperm. The 105- to 110-kDa germinal ACE was absent from the rat testicular fluid but appeared in the fluid of the anterior epididymis. Thereafter, its molecular weight shifted to 94 kDa in the corpus epididymal fluid and remained at this weight in the caudal region. The 105- to 110-kDa immunoreactive protein was present in testicular rat sperm extract but was completely absent from epididymal sperm extracts. Western blot analysis of testicular and epididymal tissue extracts from the rat and mouse also confirmed that the germinal enzyme was absent from the epididymal sperm cell. Our results demonstrated that the rodent germinal ACE is released from the testicular sperm membrane when sperm enter the epididymis, a process similar to that observed in domestic mammals. This result is discussed in view of the suggested role for this enzyme in sperm fertility.     

Klaivanolide, an antiprotozoal lactone from Uvaria klaineana

Bioguided-fractionation of a CH(2)Cl(2) extract of the stems of Uvaria klaineana (Annonaceae) led to isolation of klaivanolide, a novel bisunsaturated 7-membered lactone (5-acetoxy-7-benzoyloxymethyl-7H-oxepin-2-one), together with benzyl benzoate. Klaivanolide showed potent in vitro antileishmanial activity against both sensitive and amphotericin B-resistant promastigote forms of Leishmania donovani with IC(50) values of 1.75 and 3.12 microM, respectively. The compound also showed in vitro trypanocidal activity against trypomastigote forms of Trypanosoma brucei brucei GVR 35. Its structure was established by 1D and 2D NMR and other spectroscopic techniques.     

Interaction studies of muts and mutl with DNA containing the major cisplatin lesion and its mismatched counterpart under equilibrium and nonequilibrium conditions

The DNA mismatch repair (MMR) system participates in cis‐diamminedichloroplatinum (II) (cisplatin) cytotoxicity through signaling of cisplatin DNA lesions by yet unknown molecular mechanisms. It is thus of great interest to determine whether specialized function of MMR proteins could be associated with cisplatin DNA damage. The major cisplatin 1,2‐d(GpG) intrastrand crosslink and compound lesions arising from misincorporation of a mispaired base opposite either platinated guanine of the 1,2‐d(GpG) adduct are thought to be critical lesions for MMR signaling. Previously, we have shown that cisplatin compound lesion with a mispaired thymine opposite the 3′ platinated guanine triggers new Escherichia coli MutS ATP‐dependent biochemical activities distinguishable from those encountered with DNA mismatch consistent with a role of this lesion in MMR‐dependent signaling mechanism. In this report, we show that the major cisplatin 1,2‐d(GpG) intrastrand crosslink does not confer novel MutS postrecognition biochemical activity as studied by surface plasmon resonance spectroscopy. A fast rate of MutS ATP‐dependent dissociation prevents MutL recruitment to the major cisplatin lesion in contrast to cisplatin compound lesion which authorized MutS‐dependent recruitment of MutL with a dynamic of ternary complex formation distinguishable from that encountered with DNA mismatch substrate. We conclude that the mode of cisplatin DNA damage recognition by MutS and the nature of MMR post‐recognition events are lesion‐dependent and suggest that MMR signaling through the major cisplatin lesion is unlikely to occur. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 636–647, 2013.     

Variable Behavior of iPSCs Derived from CML Patients for Response to TKI and Hematopoietic Differentiation

Chronic myeloid leukemia disease (CML) found effective therapy by treating patients with tyrosine kinase inhibitors (TKI), which suppress the BCR-ABL1 oncogene activity. However, the majority of patients achieving remission with TKI still have molecular evidences of disease persistence. Various mechanisms have been proposed to explain the disease persistence and recurrence. One of the hypotheses is that the primitive leukemic stem cells (LSCs) can survive in the presence of TKI. Understanding the mechanisms leading to TKI resistance of the LSCs in CML is a critical issue but is limited by availability of cells from patients. We generated induced pluripotent stem cells (iPSCs) derived from CD34⁺ blood cells isolated from CML patients (CML-iPSCs) as a model for studying LSCs survival in the presence of TKI and the mechanisms supporting TKI resistance. Interestingly, CML-iPSCs resisted to TKI treatment and their survival did not depend on BCR-ABL1, as for primitive LSCs. Induction of hematopoietic differentiation of CML-iPSC clones was reduced compared to normal clones. Hematopoietic progenitors obtained from iPSCs partially recovered TKI sensitivity. Notably, different CML-iPSCs obtained from the same CML patients were heterogeneous, in terms of BCR-ABL1 level and proliferation. Thus, several clones of CML-iPSCs are a powerful model to decipher all the mechanisms leading to LSC survival following TKI therapy and are a promising tool for testing new therapeutic agents.     

Microarray Analysis of Microbiota of Gingival Lesions in Noma Patients

Noma (cancrum oris) is a gangrenous disease of unknown etiology affecting the maxillo-facial region of young children in extremely limited resource countries. In an attempt to better understand the microbiological events occurring during this disease, we used phylogenetic and low-density microarrays targeting the 16S rRNA gene to characterize the gingival flora of acute noma and acute necrotizing gingivitis (ANG) lesions, and compared them to healthy control subjects of the same geographical and social background. Our observations raise doubts about Fusobacterium necrophorum, a previously suspected causative agent of noma, as this species was not associated with noma lesions. Various oral pathogens were more abundant in noma lesions, notably Atopobium spp., Prevotella intermedia, Peptostreptococcus spp., Streptococcus pyogenes and Streptococcus anginosus. On the other hand, pathogens associated with periodontal diseases such as Aggregatibacter actinomycetemcomitans, Capnocytophaga spp., Porphyromonas spp. and Fusobacteriales were more abundant in healthy controls. Importantly, the overall loss of bacterial diversity observed in noma samples as well as its homology to that of ANG microbiota supports the hypothesis that ANG might be the immediate step preceding noma.     

Wing size but not wing shape is related to migratory behavior in a soaring bird

Both wing size and wing shape affect the flight abilities of birds. Intra and inter‐specific studies have revealed a pattern where high aspect ratio and low wing loading favour migratory behaviour. This, however, have not been studied in soaring migrants. We assessed the relationship between the wing size and shape and the characteristics of the migratory habits of the turkey vulture Cathartes aura, an obligate soaring migrant. We compared wing size and shape with migration strategy among three fully migratory, one partially migratory and one non‐migratory (resident) population distributed across the American continent. We calculated the aspect ratio and wing loading using wing tracings to characterize the wing morphology. We used satellite‐tracking data from the migratory populations to calculate distance, duration, speed and altitude during migration. Wing loading, but not aspect ratio, differed among the populations, segregating the resident population from the completely migratory ones. Unlike what has been reported in species using flapping flight during migration, the migratory flight parameters of turkey vultures were not related to the aspect ratio. By contrast, wing loading was related to most flight parameters. Birds with lower wing loading flew farther, faster, and higher during their longer journeys. Our results suggest that wing morphology in this soaring species enables lower‐cost flight, through low wing‐loading, and that differences in the relative sizes of wings may increase extra savings during migration. The possibility that wing shape is influenced by foraging as well as migratory flight is discussed. We conclude that flight efficiency may be improved through different morphological adaptations in birds with different flight mechanisms.     

A retroviral promoter and a cellular enhancer define a bipartite element which controls env ERVWE1 placental expression

The HERV-W family contains hundreds of loci diversely expressed in several physiological and pathological contexts. A unique locus termed ERVWE1 encodes an envelope glycoprotein (syncytin) involved in hominoid placental physiology. Here we show that syncytin expression is regulated by a bipartite element consisting of a cyclic AMP (cAMP)-inducible long terminal repeat (LTR) retroviral promoter adjacent to a cellular enhancer conferring a high level of expression and placental tropism. Deletion mutant analysis showed that the ERVWE1 5' LTR contains binding sites essential for basal placental activity in the region from positions +1 to +125. The region from positions +125 to +310 represents a cAMP-responsive core HERV-W promoter active in all cell types. Site-directed mutagenesis analysis highlighted the complexity of U3 regulation. ERVWE1 placenta-specific positive (e.g., T240) and negative (e.g., G71) regulatory sites were identified, as were essential sites required for basic activity (e.g., A247). The flanking sequences of the ERVWE1 provirus contain several putative regulatory elements. The upstream HERV-H and HERV-P LTRs were found to be inactive. Conversely, the 436-bp region located between the HERV-P LTR and ERVWE1 was shown to be an upstream regulatory element (URE) which is significantly active in placenta cells. This URE acts as a tissue-specific enhancer. Genetic and functional analyses of hominoid UREs revealed large differences between UREs of members of the Hominidae and the Hylobatidae. These data allowed the identification of a positive regulatory region from positions -436 to -128, a mammalian apparent LTR retrotransposon negative regulatory region from positions -128 to -67, and a trophoblast-specific enhancer (TSE) from positions -67 to -35. Putative AP-2, Sp-1, and GCMa binding sites are essential constituents of the 33-bp TSE.