The hematopoietic system produces a large number of highly specialized cell types that are derived through a hierarchical differentiation process from a common stem cell population. miRNAs are ...critical players in orchestrating this differentiation. Here, we report the development and application of a high-throughput microfluidic real-time quantitative PCR (RT-qPCR) approach for generating global miRNA profiles for 27 phenotypically distinct cell populations isolated from normal adult mouse hematopoietic tissues. A total of 80,000 RT-qPCR assays were used to map the landscape of miRNA expression across the hematopoietic hierarchy, including rare progenitor and stem cell populations. We show that miRNA profiles allow for the direct inference of cell lineage relations and functional similarity. Our analysis reveals a close relatedness of the miRNA expression patterns in multipotent progenitors and stem cells, followed by a major reprogramming upon restriction of differentiation potential to a single lineage. The analysis of miRNA expression in single hematopoietic cells further demonstrates that miRNA expression is very tightly regulated within highly purified populations, underscoring the potential of single-cell miRNA profiling for assessing compartment heterogeneity.
Studies using the nematode Caenorhabditis elegans as a model system to investigate the aging process have implicated the insulin/insulin-like growth factor-I signaling pathway
in the regulation of ...organismal longevity through its action on a subset of target genes. These targets can be classified
into genes that shorten or extend life-span upon their induction. Genes that shorten life-span include a variety of stress
response genes, among them genes encoding catalases; however, no evidence directly implicates catalases in the aging process
of nematodes or other organisms. Using genetic mutants, we show that lack of peroxisomal catalase CTL-2 causes a progeric
phenotype in C. elegans . Lack of peroxisomal catalase also affects the developmental program of C. elegans , since Î ctl-2 mutants exhibit decreased egg laying capacity. In contrast, lack of cytosolic catalase CTL-1 has no effect on either nematode
aging or egg laying capacity. The Î ctl-2 mutation also shortens the maximum life-span of the long lived Î clk-1 mutant and accelerates the onset of its egg laying period. The more rapid aging of Î ctl-2 worms is apparently not due to increased carbonylation of the major C. elegans proteins, although altered peroxisome morphology in the Î ctl-2 mutant suggests that changes in peroxisomal function, including increased production of reactive oxygen species, underlie
the progeric phenotype of the Î ctl-2 mutant. Our findings support an important role for peroxisomal catalase in both the development and aging of C. elegans and suggest the utility of the Î ctl-2 mutant as a convenient model for the study of aging and the human diseases acatalasemia and hypocatalasemia.
All organisms except the nematode Caenorhabditis elegans have been shown to possess an import system for peroxisomal proteins containing a peroxisome targeting signal type 2 (PTS2). The currently ...accepted consensus sequence for this amino-terminal nonapeptide is -(R/K)(L/V/I)X(5)(H/Q)(L/A)-. Some C.elegans proteins contain putative PTS2 motifs, including the ortholog (CeMeK) of human mevalonate kinase, an enzyme known to be targeted by PTS2 to mammalian peroxisomes. We cloned the gene for CeMeK (open reading frame Y42G9A.4) and examined the subcellular localization of CeMeK and of two other proteins with putative PTS2s at their amino termini encoded by the open reading frames D1053.2 and W10G11.11. All three proteins localized to the cytosol, confirming and extending the finding that C.elegans lacks PTS2-dependent peroxisomal protein import. The putative PTS2s of the proteins encoded by D1053.2 and W10G11.11 did not function in targeting to peroxisomes in yeast or mammalian cells, suggesting that the current PTS2 consensus sequence is too broad. Analysis of available experimental data on both functional and nonfunctional PTS2s led to two re-evaluated PTS2 consensus sequences: -R(L/V/I/Q)XX(L/V/I/H)(L/S/G/A)X(H/Q)(L/A)-, describes the most common variants of PTS2, while -(R/K)(L/V/I/Q)XX(L/V/I/H/Q)(L/S/G/A/K)X(H/Q)(L/A/F)-, describes essentially all variants of PTS2. These redefined PTS2 consensus sequences will facilitate the identification of proteins of unknown cellular localization as possible peroxisomal proteins.
The effectiveness of microsurgical technique has a direct impact on the recovery of the injured peripheral nerve. The aim of our study was to investigate the result of sciatic nerve regeneration in ...rats after complete neurotomy and after nerve repair techniques including: 1) epineural suture; 2) polyethylene glycol hydrogel (PEG) (DuraSeal); 3) fibrin sealant (Tisseel). The cross-section of distal sciatic nerve was studied at 14th, 30th and 60th days after nerve repair. Morphometry of myelinated nerve fibers in the distal stump of the sciatic nerve was performed. A significant increase in the number of myelinated nerve fibers was found, especially between 14 and 30 days. The density of myelinated nerve fibers in the distal stump at day 60 was significantly higher after using nerve repair technique including PEG and fibrin versus epineural suture (29.2 % and 32.1 % versus 21.5 %, P <0.05), and a higher level of remyelination of nerve fibers observed in the group with PEG. On day 60, complete elimination of PEG and fibrin sealant was not observed, encapsulation was found around the clusters of hydrogel. Thereby, three peripheral nerve repair techniques were equally effective, only with the use of PEG remyelination of nerve fibers was increasing.
RNA-mediated interference (RNAi) for the posttranscriptional silencing of genes was used to evaluate the importance of various peroxisomal enzymes and peroxins for the development of Caenorhabditis ...elegans and to compare the roles of these proteins in the nematode to their roles in yeasts and humans. The nematode counterparts of the human ATP-binding cassette half-transporters, the enzymes alkyldihydroxyacetonephosphate synthase and Delta(3,5)-Delta (2,4)-dienoyl-CoA isomerase, the receptors for peroxisomal membrane and matrix proteins (Pex19p and Pex5p), and components of the docking and translocation machineries for matrix proteins (Pex13p and Pex12p) are essential for the development of C. elegans. Unexpectedly, RNAi silencing of the acyl-CoA synthetase-mediated activation of fatty acids, the alpha- and beta-oxidation of fatty acids, the intraperoxisomal decomposition of hydrogen peroxide, and the peroxins Pex1p, Pex2p, and Pex6p had no apparent effect on C. elegans development. The described analysis of functional gene knockouts through RNAi provides a basis for the use of C. elegans as a valuable model system with which to study the molecular and physiological defects underlying the human peroxisomal disorders.
Mechanical damage to the peripheral nerve is a fairly common type of injury, which is characterized by a complex of long-term neurological disorders and require significant financial costs. The aim ...of this work is to evaluate the efficiency of sciatic nerve (SN) regeneration after neuroraphy using epineural suture (ES), polyethylene glycol hydrogel (PEG), and fibrin glue (FG). The studies were carried out on 30 white outbred male rats, which were divided into six experimental groups: Group №1: intact rats; Group №2: Sham operated; Group №3: complete transection of the SN; Group №4: nerve repair with ES; Group №5: nerve repair with PEG; Group №6: nerve repair with FG. Functional recovery was assessed at 1, 2, 3, 4 postoperative weeks using a walking-track analysis with subsequent determination of the sciatic nerve functional index (SFI). At 4 weeks, electroneuromyography, histological and morphometric analyzes were performed. The combined analysis indicated that PEG significantly improved functional recovery, both in the SFI index and in the skeletal muscle M-response. Compared to ES and PEG, the use of FG was reflected in a lower significance of the indicators compared to PEG. Statistical analysis indicates a positive effect of PEG and FG on nerve regeneration, although significantly greater remyelination (analysis based on fiber diameter) was confirmed only in the PEG group, which explains the faster functional recovery of the limb. PEG in the form of a hydrogel is a more promising agent in microsurgical restoration of damaged nerves as an adhesive, it promotes rapid nerve regeneration, denervated muscle re-innervation and functional limb recovery.
We set the aim to study the effect of the blood influx of large gray geese and legart geese breeds on the productive qualities of the obroshyno breed group of geese in the third generation) and the ...legarts that have been highlighted in our previous publications. With the descendants of these crosses breeding and breeding work was conducted in the direction of breeding and productive qualities improvement. For our research, four groups of 50 birds each were compiled from the livestock of geese, which were kept separately for the breeding and egg laying periods (from January to May) to ensure proper feeding and retention. The average geese live weight at the beginning of oviposition were: females OS – 6.25 kg, OB – 6.35, OS ♀ (OS ♀ x BC ♂) – 6.45, OB ♀ (OB ♀ x legart) – 6.5; males OS – 7.15 kg, OB – 7.35, OS ♂ (OS ♀ x BC ♂) – 7.45, OB ♂ (OB ♀ x legart ♂) – 7.50 kg. The duration of oviposition was higher in purebred geese (groups I and III) compared to domestic geese (groups II and IV). The average oviposition of the group I geese was highest – 41.0 pcs/head and was dominated by the group II geese by 1.2%. The weight of OS of geese of group III amounted to 40.6 pcs/head and was dominated by local geese of group IV by 2.9%. However, domestic geese (groups II and IV), by weight of eggs, outperformed purebred geese (groups I and III) by 2.1 and 4.5%, respectively. The study of incubation qualities of eggs shows that the fertilization in purebred AB and OS geese (groups I and III) was 83.9% and 83.0%, and the analogues from II and IV groups prevailed by 0.4 and 0.5%, respectively. The higher hatchability of the geese was in hybrid geese (groups II and IV) than in purebred OBS and geese OS (groups I and III). On the basis of the conducted researches the following conclusions were made: 1. The productivity of geese AB of the breed group (group I) is characterized by the following performance indicators: oviposition – 40.6 pcs. per head; egg weight – 153.2 g; fertilization – 83.5%; deductibility – 71.8%; live weight of geese at 9 weeks of age – males 4.05 kg, females – 3.67 kg; conservation – 87.0%. 2. Local geese of OB x legart (group II) had lower productivity rates: by 2.9%, they had a low fertility rate of 0.5%; fertility – 1.5%; live weight of geese at 9 weeks of age: males – 6.7%, females – 4.6%; conservation – 2.0%; at higher egg mass by 2.1%. 3. Geese of the OS of the breed group (group III) are characterized by the following performance indicators: oviposition – 40.6 pcs. per head; egg weight – 153.2 g; fertilization – 83.0%; excretion rate – 71.0%; live weight of geese at 9 weeks of age – males 4.05 kg, females – 3.67 kg; conservation – 87.0%. 4. Local geese OS x ВS (group IV) are characterized by lower indicators, respectively: with a yield of 2.9%, higher fertilization – 0.5%; with a yield of 1.5%; live weight of geese at 9 weeks of age: males – 6.7%, females – 4.6%; conservation – by 2.0%; at higher egg mass by 4.5%.
The effectiveness of microsurgical technique has a direct impact on the recovery of the injured peripheral nerve. The aim of our study was to investigate the result of sciatic nerve regeneration in ...rats after complete neurotomy and after nerve repair techniques including: 1) epineural suture; 2) polyethylene glycol hydrogel (PEG) (DuraSeal); 3) fibrin sealant (Tisseel). The cross-section of distal sciatic nerve was studied at 14th, 30th and 60th days after nerve repair. Morphometry of myelinated nerve fibers in the distal stump of the sciatic nerve was performed. A significant increase in the number of myelinated nerve fibers was found, especially between 14 and 30 days. The density of myelinated nerve fibers in the distal stump at day 60 was significantly higher after using nerve repair technique including PEG and fibrin versus epineural suture (29.2 % and 32.1 % versus 21.5 %, P <0.05), and a higher level of remyelination of nerve fibers observed in the group with PEG. On day 60, complete elimination of PEG and fibrin sealant was not observed, encapsulation was found around the clusters of hydrogel. Thereby, three peripheral nerve repair techniques were equally effective, only with the use of PEG remyelination of nerve fibers was increasing. KEY WORDS: Sciatic nerve; Regeneration; Epineural suture; Polyethylene glycol; Fibrin glue.
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