Purification and partial characterization of an acidic ribosomal protein kinase from maize

Phosphorylation and dephosphorylation of ribosomal proteins have been suggested to participate in the regulation of protein synthesis in eukaryotic organisms. The present research focuses on the purification and partial characterization of a protein kinase from maize ribosomes that specifically phosphorylates acidic ribosomal proteins. Ribosomes purified from maize axes were used as the enzyme source. Purification of ribosomes was performed by centrifugation through a 0.5 M sucrose, 0.8 M KCl cushion. A protein kinase activity present in this fraction was released by extraction with 1.5 M KCl and further purified by diethylaminoethyl cellulose column chromatography. A peak containing protein kinase activity was eluted around 400 m M KCl. Analysis of this fraction by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed one band of 38 kDa molecular mass, which cross-reacted in a western blot with antibodies raised against proteins from the large ribosomal subunit. This enzyme specifically phosphorylates one of the acidic ribosomal proteins (P₂). Its activity is inhibited by Ca²⁺ and Zn²⁺ and is activated by Mg²⁺, polylysine and spermine. The relevance of this protein kinase in reinitiating the protein synthesis process during germination is discussed.     

Species specificity and intraspecific variation in the chemical profiles of Heliconius butterflies across a large geographic range

In many animals, mate choice is important for the maintenance of reproductive isolation between species. Traits important for mate choice and behavioral isolation are predicted to be under strong stabilizing selection within species; however, such traits can also exhibit variation at the population level driven by neutral and adaptive evolutionary processes. Here, we describe patterns of divergence among androconial and genital chemical profiles at inter‐ and intraspecific levels in mimetic Heliconius butterflies. Most variation in chemical bouquets was found between species, but there were also quantitative differences at the population level. We found a strong correlation between interspecific chemical and genetic divergence, but this correlation varied in intraspecific comparisons. We identified “indicator” compounds characteristic of particular species that included compounds already known to elicit a behavioral response, suggesting an approach for identification of candidate compounds for future behavioral studies in novel systems. Overall, the strong signal of species identity suggests a role for these compounds in species recognition, but with additional potentially neutral variation at the population level.     

Cultivating <Emphasis Type="Italic">in vitro</Emphasis> coconut palms (<Emphasis Type="Italic">Cocos nucifera</Emphasis>) under glasshouse conditions with natural light,improves <Emphasis Type="Italic">in vitro</Emphasis> photosynthesis nursery survival and growth

Plantlets of coconut were cultured in vitro under three different ambient conditions including a standard culture room, a culture room inside a glasshouse with natural light but controlled temperature, and a standard glasshouse with natural light and natural fluctuations of temperature. Plantlets from the 3 treatments were compared in terms of growth, plant survival as well as net photosynthesis and efficiency of PSII (Fv/Fm ratio) both at the end of the in vitro stage and at 3 stages of ex vitro acclimatization. At the end of the in vitro stage, plantlets cultured in vitro under glasshouse conditions showed the best performance showing the highest photosynthesis rate, dry weight and number of leaves. Plantlets from the standard culture room showed the lowest photosynthesis and growth rate. After 6 months of ex vitro acclimatization, plantlets originally grown in vitro under glasshouse conditions maintained better field survival and growth rates in terms of fresh weight, dry weight and leaf number than plantlets originally grown in vitro in the standard culture room. Although more studies are required to define the reason for this effect, it is clear that the conditions of standard culture rooms are not the best for in vitro cultivation of coconut and perhaps other tropical species.     

Antioxidant activity,acetylcholinesterase and tyrosinase inhibitory potential of Pulmonaria officinalis and Centarium umbellatum extracts

In this study several investigations and tests were performed to determine the antioxidant activity and the acetylcholinesterase and tyrosinase inhibitory potential of Pulmonaria officinalis and Centarium umbellatum aqueous extracts (10% mass) and ethanolic extracts (10% mass and 70% ethanol), respectively. Moreover, for each type of the prepared extracts of P. officinalis and of C. umbellatum the content in the biologically active compounds – polyphenols, flavones and proanthocyanidins was determined. The antioxidant activity was assessed using two methods, namely the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and reducing power assay. The analyzed plant extracts showed a high acetylcholinesterase and tyrosinase inhibitory activity in the range of 72.24–94.24% (at the highest used dose – 3 mg/mL), 66.96% and 94.03% (at 3 mg/mL), respectively correlated with a high DPPH radical inhibition – 70.29–84.9% (at 3 mg/mL). These medicinal plants could provide a potential natural source of bioactive compounds and could be beneficial to the human health, especially in the neurodegenerative disorders and as sources of natural antioxidants in food industry.     

Bioturbation in matgrounds at Lake Bogoria in the Kenya Rift Valley: implications for interpreting the heterogeneous early Cambrian seafloor

Modern burrowing organisms feed on microbial organic matter in matgrounds near hot springs on the margins of Lake Bogoria, a saline alkaline lake in the Kenya Rift Valley. The burrowers produce a low-diversity trace assemblage similar to those produced by undermat miners during the Ediacaran–Cambrian transition. Despite obvious differences in body plans and phylogenetic affinities, these modern animals feed on microbes in similar ways to those inferred for primitive bilaterians. With increasing distance from hot-spring vents, outflow channels and adjacent matgrounds, the diversity and depth of the traces increase and mixgrounds become dominant. This modern extreme environment gives clues for interpreting the heterogeneous early Cambrian seafloor, with: (1) the restriction of ‘pre-agronomic revolution’ matground substrates; and (2) expansion of adjacent ‘post-agronomic revolution’ mixground areas.     

CD4+Foxp3+ regulatory T cells prolong drug-induced disease remission in (NZBxNZW) F1 lupus mice

Introduction

The ability to ameliorate murine lupus renders regulatory T cells (Treg) a promising tool for the treatment of systemic lupus erythematosus (SLE). In consideration to the clinical translation of a Treg-based immunotherapy of SLE, we explored the potential of CD4+Foxp3+ Treg to maintain disease remission after induction of remission with an established cyclophosphamide (CTX) regimen in lupus-prone (NZBxNZW) F1 mice. As a prerequisite for this combined therapy, we also investigated the impact of CTX on the biology of endogenous Treg and conventional CD4+ T cells (Tcon).

Methods

Remission of disease was induced in diseased (NZBxNZW) F1 mice with an established CTX regimen consisting of a single dose of glucocorticosteroids followed by five day course with daily injections of CTX. Five days after the last CTX injection, differing amounts of purified CD4+Foxp3+CD25+ Treg were adoptively transferred and clinical parameters, autoantibody titers, the survival and changes in peripheral blood lymphocyte subsets were determined at different time points during the study. The influence of CTX on the numbers, frequencies and proliferation of endogenous Treg and Tcon was analyzed in lymphoid organs by flow cytometry.

Results

Apart from abrogating the proliferation of Tcon, we found that treatment with CTX induced also a significant inhibition of Treg proliferation and a decline in Treg numbers in lymphoid organs. Additional adoptive transfer of 1.5 × 10⁶ purified Treg after the CTX regimen significantly increased the survival and prolonged the interval of remission by approximately five weeks compared to mice that received only the CTX regimen. The additional clinical amelioration was associated with an increase in the Treg frequency in the peripheral blood indicating a compensation of CTX-induced Treg deficiency by the Treg transfer.

Conclusions

Treg were capable to prolong the interval of remission induced by conventional cytostatic drugs. This study provides valuable information and a first proof-of-concept for the feasibility of a Treg-based immunotherapy in the maintenance of disease remission in SLE.     

Linking life history traits in successive phases of a complex life cycle: effects of larval biomass on early juvenile development in an estuarine crab, Chasmagnathus granulata

In marine benthic invertebrates with complex life cycles, recruitment success, juvenile survival, and growth may be affected by variation in both maternal factors and environmental conditions prevailing during preceding embryonic or larval development. In an estuarine crab, Chasmagnathus granulata, previous investigations have shown that initial larval biomass is positively correlated with the biomass of recently extruded eggs, and it depends also on the salinity experienced during embryogenesis. Biomass at hatching has consequences for the subsequent larval development which, in this species, comprises two alternative developmental pathways with four or five zoeal instars (short or long pathway) and a megalopa. Larvae hatching with a lower than average biomass tend to develop through the long pathway and metamorphose to megalopae with higher biomass. In the present study, we show experimentally that the long pathway produces also significantly larger juveniles (crab size measured as carapace width, biomass as dry mass, carbon and nitrogen contents). Compared with juveniles originating from the short pathway, those from the long pathway showed in successive instars longer moulting cycles and larger carapace width, but lower size increments at ecdysis. In consequence, differences in size or biomass of long pathway vs short pathway crabs tended to disappear in later instars (after stage V). Furthermore, we tested in juveniles the tolerance of starvation at three salinities (5‰, 15‰, 32‰). Tolerance of starvation was significantly higher in juveniles originating from the long pathway, indicating higher energy reserves. While salinity played only a minor role for survival, it exerted significant effects on the time of moulting to the second juvenile instar, regardless of the preceding developmental pathway. The biomass of first juveniles obtained from the short pathway showed a significant positive correlation with the biomass of the freshly hatched zoea I, but not in those from the long pathway. In conclusion, the fitness of juvenile C. granulata is linked with previous developmental processes and environmental conditions during the embryonic and larval phase. Hence, a better understanding and prediction of the recruitment success of marine benthic invertebrates with a complex life cycle may require more comprehensive life‐history investigations.