Modeling the Past and Current Distribution and Habitat Suitability for Ablepharus grayanus and A. pannonicus(Sauria: Scincidae)

Study of the climate variability in the past and present, and correlating those with changes in the distribution range of species has attracted considerable research interest. The genus Ablepharus consists of 10 recognized species, of which A. bivittatus, A. grayanus and A. pannonicus are documented from Iran. In the present study, we modeled with Max Ent the potential distribution areas and determined the suitable habitats in past(mid-Holocene [MH], and the Last Interglacial [LIG]) and their current distribution for two species of snake-eyed skinks(A. grayanus and A. pannonicus) separately. Models of the species indicated good fit by the average high area under the curve(AUC) values(A. grayanus= 0.929 ± 0.087 and A. pannonicus = 0.979 ± 0.007). Precipitation of the driest quarter of the year, mean temperature of the coldest quarter of the year, and precipitation of the driest month variables made important contributions to A. grayanus. Two important climate variables contributed importantly to A. pannonicus; temperature seasonality, and mean temperature of the wettest quarter of the year, and one topographic variable, slope. We conclude that these variables form a natural barrier for species dispersal. The MH and the LGM models indicated a larger suitable area than the current distribution.     

A novel amino acid supplementation strategy based on a stoichiometric model to enhance human IL-2 (interleukin-2) expression in high-cell-density Escherichia coli cultures

A novel amino acid supplementation strategy was developed for enhancing the production of IL-2 (interleukin-2; as a model protein) by recombinant Escherichia coli BL21 (pET21a-hil2) in fed-batch high-cell-density cultures. The amino acids most needed and their amounts were determined using a stoichiometric model, and full factorial design experiments were conducted to determine the effects of single amino acids and amino acid mixtures on production. One of the most effective amino acid mixtures was found to be leucine, aspartic acid and glycine. This amino acid mixture was utilized for the production of IL-2 in batch and fed-batch fermentations. The amount of IL-2 produced increased from 403 to 722 mg/l and from 5.15 × 103 to 8.08 × 103 mg/l in batch and fed-batch cultures respectively. The results also revealed that the above amino acid mixture specifically increases IL-2 concentration in the cells.     

Intraventricular insulin potentiates the anorexic effect of corticotropin releasing hormone in rats

Intraventricular corticotropin releasing hormone (CRH) suppresses food intake and body weight as a stress response. Insulin, acting within the brain, also suppresses food intake and body weight, and this suppression is related to caloric homeostasis. We determined if increased insulin within the brain potentiates the anorexic effects of intraventricular CRH. Rats were food deprived for 17 h each day and then given 30-min access to Ensure. One-half received continuous third ventricular infusion of synthetic cerebrospinal fluid via osmotic minipumps, and one-half received insulin (0.6 mU/day). During the infusion, rats also received 0, 0.1, 1.0, or 5.0 microg of CRH into the lateral ventricle just before access to Ensure. Insulin alone had no effect on Ensure intake or body weight. CRH dose dependently reduced Ensure intake in both groups, and the reduction was greater in the insulin group. Hence, central insulin potentiated the ability of centrally administered CRH to suppress food intake. These findings suggest that stress-related influences over food intake, particularly those mediated via CRH, interact with relative adiposity as signaled to the brain by central insulin.     

The unique interaction between the summer annual desert plant Salsola inermis Forssk and weevils residing on its roots: mutualism or parasitism?

1. Herbivores and parasites are likely to impose less damage on their host when their growth rate is slow and their dependency on the host is high. Accordingly, it was hypothesised that evolution would favour neutral or even beneficial interactions between a below-ground herbivore and a plant during the harsh season in a desert ecosystem. 2. This study characterised the relationship between the summer annual plant Salsola inermis Forssk (Chenopodiaceae) and weevils developing in a mud chamber attached to its roots in the Negev Desert of Israel. Plant seedlings were exposed to adult weevils (Conorhynchus palumbus Olivier or Menecleonus virgatus Schoenherr; Coleoptera: Curculionidae) in a controlled outside setting, to induce oviposition and larval establishment. The following were quantified: plant growth, above-ground biomass, fruit biomass, and fruit size, as well as relative C and N contents, and isotopic signatures (δ¹³C and δ¹⁵N) in plant tissues. 3. Exposure to weevils did not reduce plant survival but significantly and negatively affected plant growth and seed production. However, these effects were mainly due to above-ground herbivory by adults rather than root herbivory by larvae, and might have been overestimated. Interestingly, %N and δ¹⁵N were significantly higher, and the C:N ratio was significantly lower, in plants with larval establishment, suggesting that weevils affect the plant nitrogen budget. 4. The overall results do not support the notion of mutualistic interactions; yet, slow consumption, a low infestation level, and, possibly, N supplementation to the plant may enable the plant to tolerate herbivory under natural conditions.     

Quantifying nanoscale biochemical heterogeneity in human epithelial cancer cells using combined AFM and PTIR absorption nanoimaging

Subcellular chemical heterogeneity plays a key role in cell organization and function. However the biomechanics underlying the structure‐function relationship is governed by cell substructures which are poorly resolved using conventional chemical imaging methods. To date, advances in sub‐diffraction limited infrared (IR) nanoscopy have permitted intracellular chemical mapping. In this work we report how image analysis applied to a combination of IR absorption nanoimaging and topographic data permits quantification of chemical complexity at the nanoscale, enabling the analysis of biochemical heterogeneity in mammalian cancer cells on the scale of subcellular features. (© 2013 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Cross-linked poly(trimethylene carbonate-co-L-lactide) as a biodegradable, elastomeric scaffold for vascular engineering applications

A series of copolymers of trimethylene carbonate (TMC) and L-lactide (LLA) were synthesized and evaluated as scaffolds for the production of artificial blood vessels. The polymers were end-functionalized with acrylate, cast into films, and cross-linked using UV light. The mechanical, degradation, and biocompatibility properties were evaluated. High TMC polymers showed mechanical properties comparable to human arteries (Young's moduli of 1.2-1.8 MPa and high elasticity with repeated cycling at 10% strain). Over 84 days degradation in PBS, the modulus and material strength decreased gradually. The polymers were nontoxic and showed good cell adhesion and proliferation over 7 days using human mesenchymal stem cells. When implanted into the rat peritoneal cavity, the polymers elicited formation of tissue capsules composed of myofibroblasts, resembling immature vascular smooth muscle cells. Thus, these polymers showed properties which were tunable and favorable for vascular tissue engineering, specifically, the growth of artificial blood vessels in vivo.     

A neuron-specific cytoplasmic dynein isoform preferentially transports TrkB signaling endosomes

Cytoplasmic dynein is the multisubunit motor protein for retrograde movement of diverse cargoes to microtubule minus ends. Here, we investigate the function of dynein variants, defined by different intermediate chain (IC) isoforms, by expressing fluorescent ICs in neuronal cells. Green fluorescent protein (GFP)-IC incorporates into functional dynein complexes that copurify with membranous organelles. In living PC12 cell neurites, GFP-dynein puncta travel in both the anterograde and retrograde directions. In cultured hippocampal neurons, neurotrophin receptor tyrosine kinase B (TrkB) signaling endosomes are transported by cytoplasmic dynein containing the neuron-specific IC-1B isoform and not by dynein containing the ubiquitous IC-2C isoform. Similarly, organelles containing TrkB isolated from brain by immunoaffinity purification also contain dynein with IC-1 but not IC-2 isoforms. These data demonstrate that the IC isoforms define dynein populations that are selectively recruited to transport distinct cargoes.