Development of bis-locked nucleic acid (bisLNA) oligonucleotides for efficient invasion of supercoiled duplex DNA

In spite of the many developments in synthetic oligonucleotide (ON) chemistry and design, invasion into double-stranded DNA (DSI) under physiological salt and pH conditions remains a challenge. In this work, we provide a new ON tool based on locked nucleic acids (LNAs), designed for strand invasion into duplex DNA (DSI). We thus report on the development of a clamp type of LNA ON—bisLNA—with capacity to bind and invade into supercoiled double-stranded DNA. The bisLNA links a triplex-forming, Hoogsteen-binding, targeting arm with a strand-invading Watson–Crick binding arm. Optimization was carried out by varying the number and location of LNA nucleotides and the length of the triplex-forming versus strand-invading arms. Single-strand regions in target duplex DNA were mapped using chemical probing. By combining design and increase in LNA content, it was possible to achieve a 100-fold increase in potency with 30% DSI at 450 nM using a bisLNA to plasmid ratio of only 21:1. Although this first conceptual report does not address the utility of bisLNA for the targeting of DNA in a chromosomal context, it shows bisLNA as a promising candidate for interfering also with cellular genes.     

Polyamines affect the cellular growth and structure of pro‐embryogenic masses in Araucaria angustifolia embryogenic cultures through the modulation of proton pump activities and endogenous levels of polyamines

Polyamines (PAs) are abundant polycationic compounds involved in many physiological processes in plants, including somatic embryogenesis. This study investigates the role of PAs on cellular growth and structure of pro‐embryogenic masses (PEMs), endogenous PA and proton pump activities in embryogenic suspension cultures of Araucaria angustifolia. The embryogenic suspension cultures were incubated with putrescine (Put), spermidine (Spd), spermine (Spm) and the inhibitor methylglyoxal‐bis(guanylhydrazone) (MGBG), respectively (1 mM). After 24 h and 21 days, the cellular growth and structure of PEMs, endogenous PA contents and proton pump activities were analyzed. The addition of Spm reduced the cellular growth and promoted the development of PEMs in embryogenic cultures, which could be associated with a reduction in the activities of proton pumps, such as H⁺‐ATPase P‐ and V‐types and H⁺‐PPases, and alterations in the endogenous PA contents. Spm significantly affected the physiology of the A. angustifolia somatic embryogenesis suspension, as it potentially affects cellular growth and structure of PEMs through the modulation of proton pump activities. This work demonstrates the involvement of exogenous PAs in the modulation of cellular growth and structure of PEMs, endogenous PA levels and proton pump activities during somatic embryogenesis. To our knowledge, this study is the first to report a relationship between PAs and proton pump activities in these processes. The results obtained in this study offer new perspectives for studies addressing the role of PAs and proton pump on somatic embryogenesis in this species.     

Diphenyl Diselenide Reduces Mechanical and Thermal Nociceptive Behavioral Responses After Unilateral Intrastriatal Administration of 6-Hydroxydopamine in Rats

Parkinson’s disease (PD) patients, in addition to motor dysfunction, also present alterations in pain sensation. The present study characterized the antinociceptive effects of diphenyl diselenide ((PhSe)₂) in a model of nociception induced by unilateral, intrastriatal 6-hydroxydopamine (6-OHDA) injection in rats. Male adult Wistar rats received 20 μg/3 μl of 6-OHDA (in saline solution containing 0.02 % of ascorbic acid) or 3 μl of vehicle into the right striatum (1.0 mm anterior, 3.0 mm lateral, and 5.0 mm ventral—with respect to the bregma). Thirty days after injection, rats received (PhSe)₂ intragastrically at a dose of 10 mg/kg 1 h before behavioral tests (von Frey hairs, hot plate, tail immersion, formalin, and open field). Our results demonstrated that 6-OHDA injection to rats augmented the response frequency of von Frey hairs (VHF) stimulation, besides reducing the thermal withdrawal latency in the hot plate test. Importantly, the (PhSe)₂ treatment decreased the mechanical allodynia measured by the response frequency of VHF stimulation and diminished the thermal nociception in the hot plate test in 6-OHDA-injected rats. In conclusion, these results revealed that a single oral administration of (PhSe)₂ 1 h prior to the accomplishment of the behavioral tests was effective to attenuate the increased mechanical and thermal nociception caused by a single intrastriatal 6-OHDA injection to rats. Furthermore, other clarifying studies are warranted to improve the evidence bases for future clinical use of (PhSe)₂ as a new alternative therapy for the treatment of painful symptoms associated to PD.     

The Neotropical Genus Notodiaptomus Kiefer, 1936 (Calanoida: Diaptomidae): Redescription of the Type Species Notodiaptomus deitersi (Poppe, 1891) and Designation of a Neotype

Ribautia williamsi sp. nov., a new dwarf geophilomorph centipede from the Lower Urubamba Region, Peruvian Amazonia, is described and illustrated based on the holotype female. The new species is characterized by having the coxal organs grouped in clusters (three of these in each coxopleuron of the ultimate leg-bearing segment) and ventral pore-fields present along all the body; these two combined traits being shared by five other Neotropical species currently included in the genus Ribautia Brölemann, 1909, i.e. R. centralis (Silvestri, 1907) (from Colombia and Brazil), R. difficilis Pereira, Minelli &; Barbieri, 1995 (from Brazil), R. montana Kraus, 1954 (from Peru), R. peruana (Verhoeff, 1941) (from Peru), and R. titicacae (Turk, 1955) (from Peru). The new taxon is differentiated from the aforementioned species by the low number of leg-bearing segments and small body length; it is included in a key which will enable the identification of all known Neotropical members having coxal organs grouped in clusters. R. williamsi sp. nov. is the 14th species of Ribautia recorded from Peru.

http://zoobank.org/urn:lsid:zoobank.org:pub:D9FA5FAF-7652-4A5B-AC09-8783F05A694D     

Bivariate and Multivariate Analyses of the Influence of Blood Variables of Patients Submitted to Roux-en-Y Gastric Bypass on the Stability of Erythrocyte Membrane against the Chaotropic Action of Ethanol

The stability of the erythrocyte membrane, which is essential for the maintenance of cell functions, occurs in a critical region of fluidity, which depends largely on its composition and the composition and characteristics of the medium. As the composition of the erythrocyte membrane is influenced by several blood variables, the stability of the erythrocyte membrane must have relations with them. The present study aimed to evaluate, by bivariate and multivariate statistical analyses, the correlations and causal relationships between hematologic and biochemical variables and the stability of the erythrocyte membrane against the chaotropic action of ethanol. The validity of this type of analysis depends on the homogeneity of the population and on the variability of the studied parameters, conditions that can be filled by patients who undergo bariatric surgery by the technique of Roux-en-Y gastric bypass since they will suffer feeding restrictions that have great impact on their blood composition. Pathway analysis revealed that an increase in hemoglobin leads to decreased stability of the cell, probably through a process mediated by an increase in mean corpuscular volume. Furthermore, an increase in the mean corpuscular hemoglobin (MCH) leads to an increase in erythrocyte membrane stability, probably because higher values of MCH are associated with smaller quantities of red blood cells and a larger contact area between the cell membrane and ethanol present in the medium.     

Repetitive somatic embryogenesis from leaves of the medicinal plant Petiveria alliacea L.

Leaf segments from in vitro-grown shoot cultures of Petiveria alliacea were incubated on Murashige and Skoog (MS) medium supplemented with different concentrations of zeatin, thidiazuron, 2,4-dichlorophenoxyacetic acid (2,4-D) or picloram (PIC). Direct somatic embryogenesis was induced in response to all tested concentrations of 2,4-D and PIC. Primary somatic embryos displayed highly repetitive embryogenesis, both on the induction medium and in liquid hormone-free MS medium. Plantlets were obtained from these secondary embryos at an estimated frequency of 5 %, after 180 days of culture on half-strength MS medium gelled with 0.2 % Phytagel. Simultaneous development of friable non-embryogenic callus was also observed on media containing PIC or 2,4-D at different concentrations. Cell suspension cultures initiated from these callus tissues did not show an increase in biomass. The embryogenic portions formed at the surface of the explants in response to 20.0 μM PIC were inoculated in hormone-free full-or half-strength liquid MS medium (MS0) and showed high rates of secondary embryogenesis, resulting in the production of a mean of 35 embryos for each embryo inoculated at the culture initiation. Embryos that started the conversion process in the liquid MS0 medium originated whole plants at a frequency of 100 % when transferred to MS0 medium solidified with 0.7 % agar. Acclimatization was achieved in 90 % of the converted plantlets, with the production of phenotypically normal plants. This system is potentially useful for the micropropagation of this species, as well as for the production of substances with pharmacological interest, such as dibenzyl trisulfide.     

The Potential Role of Scattered Trees for Ant Conservation in an Agriculturally Dominated Neotropical Landscape

Although biological conservation has traditionally focused on the protection of pristine areas, it is becoming increasingly evident that efforts should also be made toward the maintenance of biological diversity in human‐managed ecosystems. We evaluated the potential role of scattered, remnant trees in enhancing ant diversity in agricultural lands within a biodiversity hotspot, namely the Cerrado savannas of central Brazil. Ant collections were performed in, beneath, and away from the crowns of a native tree species growing in planted pastures, soy fields, and in small (<400 ha) savanna reserves. Significantly more ant species were found beneath than 30 m away from scattered trees. The magnitude of this effect was similar in soy fields and in pastures at all scales of our analyses, except at the landscape scale where the effect was comparatively greater in soy fields. Most of the species that occurred more frequently beneath than away from trees nest on ground, indicating that the conservation value of scattered trees goes beyond the mere protection of arboreal ant species. Soy plantations presented a particular species‐poor ground‐dwelling fauna when compared with savannas, whereas differences in the number and composition of arboreal species were less marked. In contrast, the diversity of arboreal‐ and ground‐dwelling ants recorded in and beneath pasture trees was nearly as high as the one found in savannas. It is suggested that pasture trees can have an important value for ant conservation off reserves, particularly in regions where most of the native vegetation has already been cleared.