Synthesis,Structural and Pharmacological Characterizations of CIC,a Novel α-Conotoxin with an Extended N-Terminal Tail

Cone snails are venomous marine predators that rely on fast-acting venom to subdue their prey and defend against aggressors. The conotoxins produced in the venom gland are small disulfide-rich peptides with high affinity and selectivity for their pharmacological targets. A dominant group comprises α-conotoxins, targeting nicotinic acetylcholine receptors. Here, we report on the synthesis, structure determination and biological activity of a novel α-conotoxin, CIC, found in the predatory venom of the piscivorous species Conus catus and its truncated mutant Δ-CIC. CIC is a 4/7 α-conotoxin with an unusual extended N-terminal tail. High-resolution NMR spectroscopy shows a major influence of the N-terminal tail on the apparent rigidity of the three-dimensional structure of CIC compared to the more flexible Δ-CIC. Surprisingly, this effect on the structure does not alter the biological activity, since both peptides selectively inhibit α3β2 and α6/α3β2β3 nAChRs with almost identical sub- to low micromolar inhibition constants. Our results suggest that the N-terminal part of α-conotoxins can accommodate chemical modifications without affecting their pharmacology.     

The contribution of motorway stormwater retention ponds to the biodiversity of aquatic macroinvertebrates

Biodiversity conservation does predominantly focus on protected natural areas, but has to consider also the usually Human-dominated matrix in which these natural areas are embedded. Here we study highway stormwater retention ponds, which may act as refuges for native flora and fauna and contribute to the maintenance of biodiversity in Human-dominated landscapes. However, the biodiversity supported by such artificial ponds has received little attention so far. Using standardised methods, we addressed the potential role of highway stormwater ponds as refuges by comparing aquatic macroinvertebrate communities (Coleoptera, Heteroptera, Odonata and Gastropoda) in highway stormwater ponds with ponds in the wider landscape. As expected from their pollutant retention function, highway ponds differed in abiotic conditions from surrounding ponds. However, they supported aquatic macroinvertebrate communities at least as rich and diverse at the family level as surrounding ponds and exhibited similar variability in family community composition and structure. The main difference we observed was a higher abundance of small and/or short-lived invertebrates in the highway ponds. These similar community compositions and structures suggest that highway ponds contribute to the biodiversity of the pond network at a regional scale. Thus, road practitioners should consider highway ponds not only for their hydrological and pollutant retaining purposes but also as a possibility to increase the role of highway verges as a refuge and, consequently, landscape connectivity. The management of these water bodies should recognise their potential for biodiversity especially in Human-dominated landscapes.     

Comparison of medetomidine—morphine and medetomidine—methadone for sedation,isoflurane requirement and postoperative analgesia in dogs undergoing laparoscopy

Objective

To compare the effects of intravenous (IV) medetomidine-morphine and medetomidine-methadone on preoperative sedation, isoflurane requirements and postoperative analgesia in dogs undergoing laparoscopic surgery.

Use of cis-atracurium to maintain moderate neuromuscular blockade in experimental pigs

Objective

To determine the dose of cis-atracurium needed to produce a moderate neuromuscular blockade (NMB) in pigs.

Use the insiders: could insect facultative symbionts control vector-borne plant diseases?

Insect vector-borne plant diseases, particularly those whose causative agents are viral, or phloem- and xylem-restricted bacteria, greatly impact crop losses. Since plants are immobile, the epidemiology of vector-borne diseases greatly depends on insect vectors, which are the only means of dissemination for many pathogens. The effectiveness of a vector-borne pathogen relies upon the vectorial capacity, which is affected by vector density, feeding activity on hosts, longevity before and after pathogen ingestion, duration of the incubation period, and vector competence. During the last decade, research on human vector-borne epidemics has stimulated interest in novel control strategies targeting different parts of the vector cycle, and our purpose here is to draw parallels between this field of research and agronomy. We review the literature on insect vectors of crop diseases and their symbiotic microorganisms with the aim of suggesting future integrated management techniques based on current research on insect-vectored human diseases. Vector transmission is a complex process and different modes of transmission are encountered irrespective of the pathogen. Facultative symbionts have varied effects on life history traits that could be used for vector population control. Symbiont selection, transformation, and their manner of dissemination are important when developing an integrated vector management system based on symbiont manipulation. In the short term, progress on our knowledge of the microflora of insect vectors of plant diseases must be made. In the long term, symbiont manipulation, which has been successfully demonstrated against human insect-vectored diseases, could be adapted to insect-borne plant diseases to increase sustainable crop production.     

Contrasting strategies to cope with chilling stress among clones of a tropical tree, Hevea brasiliensis

Eight Hevea brasiliensis Muell. Arg. clones (GT1, YUNYAN77-4, IRCA707, IRCA317, PB217, PB260, PR107 and RRIM600) were compared for their tolerance towards chilling stress. Net photosynthesis (Pn), stomatal conductance (Gs), optimal and effective photochemical efficiencies (F(v)/F(m) and ), non-photochemical quenching, cellular lysis and leaf necrosis were measured on trees chilled at 10?°C for 96?h, as well as upon recovery at 28?°C. In addition, ascorbate peroxidase, catalase, dehydroascorbate reductase, glutathione reductase, monodehydroascorbate reductase and superoxide dismutase activities were monitored. Clone RRIM600 appeared to be the most tolerant, because it showed no cellular lysis or leaf necrosis and the best recovery as revealed by Pn, Gs, F(v)/F(m) and . Its ability to sustain chilling stress seemed related in part to the fast closure of stomata, suggesting an 'avoidance strategy' for this clone. IRCA707, GT1 and YUNYAN77-4 were also tolerant to the cold treatment as only a few leaf injuries were observed. However, YUNYAN77-4 showed a particular behaviour with a large stomata opening during the first hour of chilling, some photosynthetic activity after 96?h at 10?°C, but the slowest recovery in Pn. The greatest cell or leaf damage was observed on PB260, IRCA317, PR107 and PB217 clones, thus classified as sensitive to chilling. These clones showed the strongest decrease in Pn, F(v)/F(m) and and the slowest recovery for F(v)/F(m) and , indicating a high sensitivity of photosystem II to cold temperatures. Punctual increases of various enzymatic activities were observed for all clones during chilling kinetics. During recovery, the strongest increases in enzymatic activity were observed for the most tolerant clones, suggesting that efficient reactive oxygen species elimination is a crucial step for determining chilling tolerance in Hevea although the enzymes implicated varied from one tolerant clone to another. This study points out contrasted strategies of the Hevea clones in copping with chilling stress and recovery.