Hydrogen Sulfide Donor Protects Porcine Oocytes against Aging and Improves the Developmental Potential of Aged Porcine Oocytes

Porcine oocytes that have matured in in vitro conditions undergo the process of aging during prolonged cultivation, which is manifested by spontaneous parthenogenetic activation, lysis or fragmentation of aged oocytes. This study focused on the role of hydrogen sulfide (H₂S) in the process of porcine oocyte aging. H₂S is a gaseous signaling molecule and is produced endogenously by the enzymes cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (MPST). We demonstrated that H₂S-producing enzymes are active in porcine oocytes and that a statistically significant decline in endogenous H₂S production occurs during the first day of aging. Inhibition of these enzymes accelerates signs of aging in oocytes and significantly increases the ratio of fragmented oocytes. The presence of exogenous H₂S from a donor (Na₂S.9H₂O) significantly suppressed the manifestations of aging, reversed the effects of inhibitors and resulted in the complete suppression of oocyte fragmentation. Cultivation of aging oocytes in the presence of H₂S donor positively affected their subsequent embryonic development following parthenogenetic activation. Although no unambiguous effects of exogenous H₂S on MPF and MAPK activities were detected and the intracellular mechanism underlying H₂S activity remains unclear, our study clearly demonstrates the role of H₂S in the regulation of porcine oocyte aging.     

Proteome alterations in gamma-irradiated human T-lymphocyte leukemia cells

Analyses of the protein expression profiles of irradiated cells may be beneficial for identification of new biomolecules of radiation-induced cell damage. Therefore, in this study we exploited the proteomic approach to identify proteins whose expression is significantly altered in gamma-irradiated human T-lymphocyte leukemia cells. MOLT-4 cells were irradiated with 7.5 Gy and the cell lysates were collected at different times after irradiation (2, 5 and 12 h). The proteins were separated by two-dimensional electrophoresis and quantified using an image evaluation system. Proteins exhibiting significant radiation-induced alterations in abundance were identified by peptide mass fingerprinting. We identified 14 proteins that were either up- or down-regulated. Cellular levels of four of the proteins (Rho GDP dissociation inhibitor 1 and 2, Ran binding protein 1, serine/threonine protein kinase PAK2) were further analyzed by two-dimensional immunoblotting to confirm the data obtained from proteome analysis. All identified proteins were classified according to their cellular function, including their participation in biochemical and signaling pathways. Taken together, our results suggest the feasibility of the proteome method for monitoring of cellular radiation responses.     

The synthesis and anticancer activity of analogs of the indole phytoalexins brassinin, 1-methoxyspirobrassinol methyl ether and cyclobrassinin

An effective synthesis of analogs of the indole phytoalexin cyclobrassinin with NR₁R₂ group instead of SCH₃ was developed starting from indole-3-carboxaldehyde. The target compounds were prepared by spirocyclization of 1-Boc-thioureas with the formation of isolable spiroindoline intermediates, followed by the trifluoroacetic acid-induced cascade reaction consisting of methanol elimination, deprotection and rearrangement of the iminium ion. The structures of novel products were elucided by the ¹H and ¹³C NMR spectroscopy, including HMBC, HSQC, COSY, NOESY and DEPT measurements. Several newly synthesized compounds demonstrated significant antiproliferative/cytotoxic activity against human leukemia and solid tumor cell lines, as well as remarkable selectivity of these effects against cancer cells relative to the non-malignant HUVEC cells.     

Toward the insulin-IGF-I intermediate structures: functional and structural properties of the [TyrB25NMePheB26] insulin mutant

The origins of differentiation of insulin from insulin-like growth factor I (IGF-I) are still unknown. To address the problem of a structural and biological switch from the mostly metabolic hormonal activity of insulin to the predominant growth factor activities of IGF-I, an insulin analogue with IGF-I-like structural features has been synthesized. Insulin residues Phe(B25) and Tyr(B26) have been swapped with the IGF-I-like Tyr(24) and Phe(25) sequence with a simultaneous methylation of the peptide nitrogen of residue Phe(B26). These modifications were expected to introduce a substantial kink in the main chain, as observed at residue Phe(25) in the IGF-I crystal structure. These alterations should provide insight into the structural origins of insulin-IGF-I structural and functional divergence. The [Tyr(B25)NMePhe(B26)] mutant has been characterized, and its crystal structure has been determined. Surprisingly, all of these changes are well accommodated within an insulin R6 hexamer. Only one molecule of each dimer in the hexamer responds to the structural alterations, the other remaining very similar to wild-type insulin. All alterations, modest in their scale, cumulate in the C-terminal part of the B-chain (residues B23-B30), which moves toward the core of the insulin molecule and is associated with a significant shift of the A1 helix toward the C-terminus of the B-chain. These changes do not produce the expected bend of the main chain, but the fold of the mutant does reflect some structural characteristics of IGF-1, and in addition establishes the CO(A19)-NH(B25) hydrogen bond, which is normally characteristic of T-state insulin.     

Biodiversity,biogeography, and connectivity of polychaetes in the world's largest marine minerals exploration frontier

Aim

The abyssal Clarion-Clipperton Zone (CCZ), Pacific Ocean, is an area of commercial importance owing to the growing interest in mining high-grade polymetallic nodules at the seafloor for battery metals. Research into the spatial patterns of faunal diversity, composition, and population connectivity is needed to better understand the ecological impacts of potential resource extraction. Here, a DNA taxonomy approach is used to investigate regional-scale patterns of taxonomic and phylogenetic alpha and beta diversity, and genetic connectivity, of the dominant macrofaunal group (annelids) across a 6 million km² region of the abyssal seafloor.

Location

The abyssal seafloor (3932–5055 m depth) of the Clarion-Clipperton Zone, equatorial Pacific Ocean.

Methods

We used a combination of new and published barcode data to study 1866 polychaete specimens using molecular species delimitation. Both phylogenetic and taxonomic alpha and beta diversity metrics were used to analyse spatial patterns of biodiversity. Connectivity analyses were based on haplotype distributions for a subset of the studied taxa.

Results

DNA taxonomy identified 291–314 polychaete species from the COI and 16S datasets respectively. Taxonomic and phylogenetic beta diversity between sites were relatively high and mostly explained by lineage turnover. Over half of pairwise comparisons were more phylogenetically distinct than expected based on their taxonomic diversity. Connectivity analyses in abundant, broadly distributed taxa suggest an absence of genetic structuring driven by geographical location.

Main Conclusions

Species diversity in abyssal Pacific polychaetes is high relative to other deep-sea regions. Results suggest that environmental filtering, where the environment selects against certain species, may play a significant role in regulating spatial patterns of biodiversity in the CCZ. A core group of widespread species have diverse haplotypes but are well connected over broad distances. Our data suggest that the high environmental and faunal heterogeneity of the CCZ should be considered in future policy decisions.     

How Do Different Watering Regimes Affect the Growth,Chlorophyll Fluorescence,Phytohormone, and Phenolic Acid Content of Greenhouse-Grown Ceratotheca triloba?

We evaluated the effect of different watering regimes on the growth, chlorophyll fluorescence, phytohormones, and phenolic acids in Ceratotheca triloba (Bernh.) Hook.f., a commonly consumed African indigenous leafy vegetable. The study was conducted in the greenhouse under different watering regimes [seven (daily); three (thrice); two (twice); one (once) day(s) per week] for a period of 2 and 4-months. In each pot (7.5 cm diameter; 150 ml volume), 50 ml of water was applied per treatment. At the end of the experiment, plant growth, chlorophyll fluorescence, phytohormones, and phenolic acids were determined. A decrease in water availability resulted in a consistent decline in plant growth after a 4-month growth period. The severity of reduced water availability was more noticeable in plants watered once a week with a 1.4-fold reduction in growth and quantum efficiency of PSII (Fv/Fm) value of 0.80. The significant decline in growth and chlorophyll fluorescence was probably due to the increased production of abscisic acid (ABA) and cytokinin (CK) content together with the detected phytohormones in plants with restricted water supply. Furthermore, plants watered once a week had a trade-off between growth and phenolic acid production, with significantly higher (threefolds) concentrations of vanillic, ferulic, caffeic, and 4-coumaric acids in 4-month-old plants. Even though C. triloba grew best in well-watered soil, the plant had the potential to adapt and survive in soils with limited water supply for longer periods of growth. These findings suggest that regulation of phytohormones and phenolic acids played an important role in improving the growth of C. triloba under limited water conditions.

     

Local adaptation of annual weed populations to habitats differing in disturbance regime

Plants have evolved several strategies to cope with disturbance, and one strategy is tolerance. In tolerance, plants store resources (meristems, carbohydrates) so that they can resprout after disturbance and thereby compensate to some degree for losses. Because tolerance is costly (it occurs at the expense of current growth), we can expect adaptation to the local disturbance regime. In this study, we determined whether populations of a common European annual weed, Euphorbia peplus, are adapted to the local disturbance regime. We hypothesized that the tolerance and hence compensation for losses in seed and biomass production after experimental damage are greater in plants from more severely disturbed than from less severely disturbed populations. We also hypothesized that transgenerational effects can alter adaptation. We found that compensation for biomass loss to damage was greater for plants from more severely disturbed habitats than for plants from less severely disturbed habitats. This, however, was not at the expense of growth before damage because plants from both disturbance regimes did not show differences when not damaged. Transgenerational effects played a positive role in adaptation to disturbance during germination and maturity. We conclude that local adaptation together with transgenerational effects have evolved in more severely disturbed populations but not in less severely disturbed populations of E. peplus.