Molecular cloning and expression analysis of major intrinsic protein gene in Chlamydomonas sp. ICE-L from Antarctica

Extremophiles - Major intrinsic proteins (MIPs) form channels facilitating the passive transport of water and other small polar molecules across membranes. In this study, the complete open reading...     

LZAP is a novel Wip1 binding partner and positive regulator of its phosphatase activity in vitro

The phosphatase Wip1 attenuates the DNA damage response (DDR) by removing phosphorylation marks from a number of DDR proteins (p53, MDM2, Chk1/2, p38). Wip1 also dephosphorylates and inactivates RelA. Notably, LZAP, a putative tumor suppressor, has been linked to dephosphorylation of several of these substrates, including RelA, p38, Chk1, and Chk2. LZAP has no known catalytic activity or functional motifs, suggesting that it exerts its effects through interaction with other proteins. Here we show that LZAP binds Wip1 and stimulates its phosphatase activity. LZAP had been previously shown to bind many Wip1 substrates (RelA, p38, Chk1/2), and our results show that LZAP also binds the previously identified Wip1 substrate, MDM2. This work identifies 2 novel Wip1 substrates, ERK1 and HuR, and demonstrates that HuR is a binding partner of LZAP. Pleasingly, LZAP potentiated Wip1 catalytic activity toward each substrate tested, regardless of whether full-length substrates or phosphopeptides were utilized. Since this effect was observed on ERK1, which does not bind LZAP, as well as for each of 7 peptides tested, we hypothesize that LZAP binding to the substrate is not required for this effect and that LZAP directly binds Wip1 to augment its phosphatase activity.     

<Emphasis Type="Italic">Myrcia incompleta</Emphasis> (Myrtaceae), a new species from Amazonian Brazil

Myrcia incompleta, from the northern Brazilian states of Amazonas and Rondônia, is described and illustrated. This species is apparently related to Calyptranthes paniculata and C. speciosa, from which it is distinguished mainly by its narrower leaves with midvein strongly raised adaxially and shorter, pauciflorous inflorescences. Conservation status for the species is proposed.     

The small GTPase Rac1 is involved in the maintenance of stemness and malignancies in glioma stem-like cells

A subpopulation of cancer cells with stem cell properties is responsible for tumor formation, maintenance, and malignant progression; however, the molecular mechanisms underlying the maintenance of cancer stem-like cell properties have remained unclear. Here, we show that the Rho family GTPase Rac1 is involved in the glioma stem-like cell (GSLC) maintenance and tumorigenicity in human glioma. The Rac1-Pak signaling was markedly activated in GSLCs. Knockdown of Rac1 caused reduction of expression of GSLC markers, self-renewal-related proteins and neurosphere formation. Moreover, down-regulation of Rac1 suppressed the migration, invasion, and malignant transformation in GSLCs. Furthermore, inhibition of Rac1 enhanced radiation sensitivity of GSLCs. These results indicate that the small GTPase Rac1 is involved in the maintenance of stemness and malignancies in GSLCs.     

Molecular characterization of tomato leaf curl China virus, infecting tomato plants in China, and functional analyses of its associated betasatellite

A novel tomato-infecting begomovirus from Guangxi province, China, was identified and characterized, for which the name Tomato leaf curl China virus (ToLCCNV) was proposed. Phylogenetic and recombination analyses of the virus genomic sequences suggested that ToLCCNV may have arisen by recombination among Tomato leaf curl Vietnam virus (ToLCVV), Tomato leaf curl Gujarat virus (ToLCGV), and an unknown virus. A betasatellite molecule was found to be associated with ToLCCNV (ToLCCNB), and its complete nucleotide sequences were determined. Infectious clones of ToLCCNV and ToLCCNB were constructed and then used for agro-inoculation of plants; ToLCCNV alone infected Nicotiana benthamiana, Nicotiana glutinosa, Petunia hybrida, and Solanum lycopersicum plants, but no symptoms were induced. ToLCCNB was required for induction of leaf curl disease in these hosts. The βC1 protein of ToLCCNB was identified as a suppressor of RNA silencing and accumulated primarily in the nucleus. Deletion mutagenesis of βC1 showed that the central part of βC1 (amino acids 44 to 74) was responsible for both the suppressor activity and nuclear localization.     

Autoregulatory Properties of (+)-Thujopsene and Influence of Environmental Conditions on Its Production by <Emphasis Type="Italic">Penicillium decumbens</Emphasis>

A Penicillium decumbens strain was collected from a water-damaged building, and the production of microbial volatile organic compounds (MVOCs) was investigated by means of headspace solid-phase microextraction, followed by GC-MS analysis. The strain was characterized by a high production of (+)-thujopsene. The influence of various temperatures, relative humidity (RH) values, substrates, and inoculum concentrations on fungal growth and (+)-thujopsene production was studied. The optimal temperature and relative humidity for P. decumbens growth were 30°C and 100% RH, respectively. In general, the more favourable the incubation parameters were for growth, the faster maximum (+)-thujopsene production was reached. Moreover, the antifungal activity of thujopsene was tested against 16 fungal strains. The growth of five of these fungal strains was negatively affected both by thujopsene alone and when grown in contact with the MVOCs produced by P. decumbens. Following these results and since growth of P. decumbens itself was also inhibited by thujopsene, an autoregulatory function for this compound was proposed. Few data are present in the literature about chemical communication between fungi. The present research could, therefore, contribute to understanding fungal metabolism and behaviour in indoor environments.     

Studies on synthesis, characterization, and G-quadruplex binding of Ru(II) complexes containing two dppz ligands

In this work, the interaction between the guanine-rich single-strand oligomer AG₃(T₂AG₃)₃ quadruplex and two Ru(II) complexes, [Ru(L¹)(dppz)₂](PF₆)₄ (1) and [Ru(L²)(dppz)₂](PF₆)₄ (2) (L¹ = 5,5′-di(1-(trimethylammonio)methyl)-2,2′-dipyridyl cation, L² = 5,5′-di(1-(triethylammonio)methyl)-2,2′-dipyridyl cation, dppz = dipyrido[3,2-a:2′,3′-c] phenazine), has been studied by UV-Visible, fluorescence, DNA melting, and circular dichroism in K⁺ buffer. The two complexes after binding to G-quadruplex have shown different DNA stability and fluorescence enhancement. The results show that both complexes can induce the stabilization of quadruplex DNA. ΔT_m values of complexes 1 and 2 at [Ru]/[DNA] ratio of 1:1 were 9.4 and 7.0, respectively. Binding stoichiometry along with the quadruplex was investigated through a luminescence-based Job plot. The major inflection points for complexes 1 and 2 were 0.49 and 0.46, respectively. The data were consistent with the binding mode at a [quadruplex]/[complex] ratio of 1:1. In addition, the conformation of G-quadruplex was not changed by the complexes at the high ionic strength of K⁺ buffer.