A Transient Receptor Potential Ion Channel in Chlamydomonas Shares Key Features with Sensory Transduction-Associated TRP Channels in Mammals

Sensory modalities are essential for navigating through an ever-changing environment. From insects to mammals, transient receptor potential (TRP) channels are known mediators for cellular sensing. Chlamydomonas reinhardtii is a motile single-celled freshwater green alga that is guided by photosensory, mechanosensory, and chemosensory cues. In this type of alga, sensory input is first detected by membrane receptors located in the cell body and then transduced to the beating cilia by membrane depolarization. Although TRP channels seem to be absent in plants, C. reinhardtii possesses genomic sequences encoding TRP proteins. Here, we describe the cloning and characterization of a C. reinhardtii version of a TRP channel sharing key features present in mammalian TRP channels associated with sensory transduction. In silico sequence-structure analysis unveiled the modular design of TRP channels, and electrophysiological experiments conducted on Human Embryonic Kidney-293T cells expressing the Cr-TRP1 clone showed that many of the core functional features of metazoan TRP channels are present in Cr-TRP1, suggesting that basic TRP channel gating characteristics evolved early in the history of eukaryotes.     

Adipokines: biofactors from white adipose tissue. A complex hub among inflammation, metabolism, and immunity

Until the identification of leptin, the first adipokine discovered in 1994, adipose tissue was considered only as an energy storage tissue. However, it is now clear that adipose tissue is an endocrine/paracrine/autocrine organ, which plays a relevant role in physiopathology of several inflammatory diseases. Actually, it is mainly involved not only in the low-grade inflammatory status in obesity but also in other relevant inflammatory conditions and autoimmune disorders. In this review article, we discuss the main biological activities of leptin, adiponectin, lipocalin-2, resistin, and visfatin, as well as their contributions to certain inflammatory conditions.     

The analysis of macromolecular interactions by sedimentation equilibrium

The study of macromolecular interactions by sedimentation equilibrium is a highly technical method that requires great care in both the experimental design and data analysis. The complexity of the interacting system that can be analyzed is only limited by the ability to deconvolute the exponential contributions of each of the species to the overall concentration gradient. This is achieved in part through the use of multi-signal data collection and the implementation of soft mass conservation. We illustrate the use of these constraints in SEDPHAT through the study of an A+B+B?AB+B?ABB system and highlight some of the technical challenges that arise. We show that both the multi-signal analysis and mass conservation result in a precise and robust data analysis and discuss improvements that can be obtained through the inclusion of data from other methods such as sedimentation velocity and isothermal titration calorimetry.     

Selenium accumulation in plants--phytotechnological applications and ecological implications

Selenium (Se) is an essential trace element for many organisms including humans, yet toxic at higher levels. Both Se deficiency and toxicity are problems worldwide. Since plants readily accumulate and volatilize Se, they may be used both as a source of dietary Se and for removing excess Se from the environment. Plant species differ in their capacity to metabolize and accumulate Se, from non-Se accumulators (< 100 mg Se/kg DW), to Se-accumulators (100-1000 mg Se/kg DW) to Se hyperaccumulators (> 1,000 mg Se/kg DW). Here we review plant mechanisms of Se metabolism in these various plant types. We also summarize results from genetic engineering that have led to enhanced plant Se accumulation, volatilization, and/or tolerance, including field studies. Before using Se-accumulating plants at a large scale we need to evaluate the ecological implications. Research so far indicates that plant Se accumulation significantly affects the plant's ecological interactions below and above ground. Selenium canprotect plants from fungal pathogens and from a variety of invertebrate and vertebrate herbivores, due to both deterrence and toxicity. However, specialist (Se-tolerant herbivores), detritivores and endophytes appear to utilize Se hyperaccumulator plants as a resource. These findings are relevant for managing phytoremediation of Se and similar elements.     

Phylodynamics of hepatitis C virus subtype 2c in the province of Córdoba, Argentina

The Hepatitis C Virus Genotype 2 subtype 2c (HCV-2c) is detected as a low prevalence subtype in many countries, except in Southern Europe and Western Africa. The current epidemiology of HCV in Argentina, a low-prevalence country, shows the expected low prevalence for this subtype. However, this subtype is the most prevalent in the central province of Córdoba. Cruz del Eje (CdE), a small rural city of this province, shows a prevalence for HCV infections of 5%, being 90% of the samples classified as HCV-2c. In other locations of Córdoba Province (OLC) with lower prevalence for HCV, HCV-2c was recorded in about 50% of the samples. The phylogenetic analysis of samples from Córdoba Province consistently conformed a monophyletic group with HCV-2c sequences from all the countries where HCV-2c has been sequenced. The phylogeographic analysis showed an overall association between geographical traits and phylogeny, being these associations significant (α = 0.05) for Italy, France, Argentina (places other than Córdoba), Martinique, CdE and OLC. The coalescence analysis for samples from CdE, OLC and France yielded a Time for the Most Common Recent Ancestor of about 140 years, whereas its demographic reconstruction showed a “lag” phase in the viral population until 1880 and then an exponential growth until 1940. These results were also obtained when each geographical area was analyzed separately, suggesting that HCV-2c came into Córdoba province during the migration process, mainly from Europe, which is compatible with the history of Argentina of the early 20th century. This also suggests that the spread of HCV-2c occurred in Europe and South America almost simultaneously, possibly as a result of the advances in medicine technology of the first half of the 20th century.     

Molecular phylogeny and paclitaxel screening of fungal endophytes from Taxus globosa

We studied the endophytic mycoflora associated with Taxus globosa, the Mexican yew. The study localities; Las Avispas (LA), San Gaspar (SG), and La Mina (LM) were three segments of cloud forest within the range of Sierra Gorda Biosphere Reserve, México. Overall, 245 endophytes were isolated and 105 representative Ascomycota (morphotaxons) were chosen for phylogenetic and genotypic characterization. Maximum likelihood analyses of large subunit of ribosomal RNA (LSU) rDNA showed well-supported clades of Dothideomycetes, Eurotiomycetes, Leotiomycetes, Pezizomycetes, and Sordariomycetes. Analyses of ITS rDNA groups showed 57 genotypes (95% sequence similarity), in general consistent with the phylogenetically delimitated taxa based on LSU rDNA sequences. The endophyte diversity measured by Fisher's α, Shanonn, and Simpson indices was ca. three-fold and ca. two-fold greater in LM than in LA and SG respectively. A screening for paclitaxel using a competitive inhibition enzyme immunoassay showed 16 positive isolates producing between 65 and 250 ng l(-1). The isolates included Acremonium, Botryosphaeria, Fusarium, Gyromitra, Nigrospora, Penicillium, three novel Pleosporales, and Xylaria.