Effects of Radio-Collars are not Contingent on Socioecological Conditions in Degus

Species-specific research on free-ranging mammals reveals a diversity of effects of radio-collars on behavior, body condition, and fitness. Although these studies indicate rather limited direct effects, radio-collars may cause effects influenced by socio-ecological conditions. Using a 7-year study on a natural population of group-living degus (Octodon degus), we tested the hypothesis that ecological (food availability, burrow density) and social (group size, group male-to-female ratio) conditions modulate effects of radio-collars on body condition (e.g., body mass, ecto- and endoparasite loads, fecal cortisol metabolites) and direct fitness (litter size, adult survival). We determined the effect of radio-collar use on degus by contrasting the presence or absence of radio-collars, quantifying the effects of the number of days carrying a radio-collar, and the relative mass of radio-collars worn by degus in central Chile between 2009 and 2015. Radio-collar use was not associated with direct effects on litter size, adult survival, or with body mass and fecal cortisol metabolites but was linked to low ecto- and endoparasite loads. These seemingly positive effects may reflect decreased mobility, or a research bias for radio-collaring larger, healthier individuals. There was no evidence that ecological and social conditions modulated radio-collar effects on degu body condition and direct fitness. These findings are consistent with evidence from other mammal studies that reported no appreciable detrimental direct or indirect effects of radio-collars. © 2021 The Wildlife Society.     

Phenotype restricted genome-wide association study using a gene-centric approach identifies three low-risk neuroblastoma susceptibility Loci

Neuroblastoma is a malignant neoplasm of the developing sympathetic nervous system that is notable for its phenotypic diversity. High-risk patients typically have widely disseminated disease at diagnosis and a poor survival probability, but low-risk patients frequently have localized tumors that are almost always cured with little or no chemotherapy. Our genome-wide association study (GWAS) has identified common variants within FLJ22536, BARD1, and LMO1 as significantly associated with neuroblastoma and more robustly associated with high-risk disease. Here we show that a GWAS focused on low-risk cases identified SNPs within DUSP12 at 1q23.3 (P = 2.07×10⁻⁶), DDX4 and IL31RA both at 5q11.2 (P = 2.94×10⁻⁶ and 6.54×10⁻⁷ respectively), and HSD17B12 at 11p11.2 (P = 4.20×10⁻⁷) as being associated with the less aggressive form of the disease. These data demonstrate the importance of robust phenotypic data in GWAS analyses and identify additional susceptibility variants for neuroblastoma.     

Evaluation of Bacillus anthracis thymidine kinase as a potential target for the development of antibacterial nucleoside analogs

Bacillus anthracis, which causes anthrax, has attracted attention because of its potential use as a biological weapon. The risk of multidrug resistance against B. anthracis increases the need for antibiotics with new molecular targets. Nucleoside analogs are well-known antiviral and anticancer prodrugs, and thymidine kinase catalyzes the rate-limiting step in the activation of pyrimidine nucleoside analogs used in chemotherapy. The thymidine kinase gene from B. anthracis Sterne strain (34F2) (Ba-TK) was cloned and expressed in E. coli, and the product was purified and characterized regarding its substrate specificity. Ba-TK phosphorylated pyrimidine nucleosides and all natural nucleoside triphosphates served as phosphate donors. Size exclusion chromatography indicated a dimeric form of Ba-TK, regardless of the presence of ATP. Thymidine was the most efficient substrate with a low K(m) value (0.6 microM) and a V(max) of 3.3 micromol dTMP mg(-1) min(-1), but deoxyuridine (K(m)=4.2 microM, V(max)=4.1 micromol dUMP mg(-1) min(-1)) was also a good substrate. Several pyrimidine analogs were also tested and analogs with 5-position modifications showed higher activities compared to analogs with 3'- and N3-position modifications. Deoxyuridine analogs were the most potent inhibitors of B. anthracis growth in vitro. These results may be used to guide future development of nucleoside analogs against B. anthracis.     

Application of an angiosperm-based classification system (BiPo) to Mediterranean coastal waters: using spatial analysis and data on metal contamination of plants in identifying sources of pressure

The Biotic Index based on Posidonia oceanica (BiPo) is a classification system for evaluation of the ecological status in Mediterranean coastal waters, developed in accordance with the EU Water Framework requirements. The aim of this study is to verify the applicability and reliability of the BiPo index to different geographical areas of the north-western Mediterranean (France, Spain and Italy), to understand whether such a classification system may be applied more extensively, as so far it has only been applied to coastal waters in Corsica. The ecological status determined for sites is verified against pressures revealed from satellite imagery and from trace metal contamination of plants, to identify the sources of pressure that may be responsible for a low ecological status. The results of this study indicate that: (i) the BiPo index responds reliably to pressures, in different areas of the Mediterranean; (ii) sites with an ecological quality ratio (EQR) close to the good/moderate boundary require particular attention to identify and reduce causes of deterioration; (iii) the support of chemical indicators, in this case metal contamination, is relevant to identify potential sources of pressure.     

Proliferation and differentiation of rat theca-interstitial cells: comparison of effects induced by platelet-derived growth factor and insulin-like growth factor-I

This study was designed to evaluate mechanisms regulating proliferation of steroidogenically active and steroidogenically inactive theca-interstitial (T-I) cells, and, specifically, to evaluate the effects of platelet-derived growth factor (PDGF) and insulin-like growth factor-I (IGF-I). T-I cells obtained from immature Sprague-Dawley rats were cultured in chemically defined media. Proliferation was assayed by thymidine incorporation and cell counting. Steroidogenically active cells were identified by the presence of 3beta-hydroxysteroid dehydrogenase activity. Flow cytometry facilitated separation of dividing cells (in S and G2/M phases of the cell cycle) from nondividing cells (in G0 and G1 phases of the cell cycle). PDGF alone (0.1-1 nM) produced a dose-dependent increase in DNA synthesis by up to 136%. IGF-I alone (10 nM) increased DNA synthesis by 56%. In the presence of both IGF-I (10 nM) and PDGF (0.1-1 nM), DNA synthesis increased by 108-214%. PDGF (1 nM) increased the total number of T-I cells by 43%; this effect was due to an increase in the number of steroidogenically inactive cells (47%). In contrast, the stimulatory effect of IGF-I (10 nM) was predominantly due to an increase in the number of steroidogenically active cells (163%). Separation of dividing cells from nondividing cells was accomplished with the aid of flow cytometry. In the absence of growth factors, the proportion of steroidogenically active cells was 35% lower among proliferating than resting cells. PDGF (1 nM) decreased the proportion of steroidogenically active cells among both proliferating and resting cells (by 43% and 16%, respectively). In contrast, IGF-I (10 nM) increased the proportion of steroidogenically active cells among proliferating cells by 56%. These findings indicate that differentiated/steroidogenically active cells divide; furthermore, PDGF and IGF-I may selectively stimulate proliferation of individual subpopulations of T-I cells, thereby providing a mechanism for development of structural and steroidogenically active components of the T-I compartment.     

Time‐dependent climate impact and energy efficiency of combined heat and power production from short‐rotation coppice willow using pyrolysis or direct combustion

A life cycle assessment of a Swedish short‐rotation coppice willow bioenergy system generating electricity and heat was performed to investigate how the energy efficiency and time‐dependent climate impact were affected when the feedstock was converted into bio‐oil and char before generating electricity and heat, compared with being combusted directly. The study also investigated how the climate impact was affected when part of the char was applied to soil as biochar to act as a carbon sequestration agent and potential soil improver. The energy efficiencies were calculated separately for electricity and heat as the energy ratios between the amount of energy service delivered by the system compared to the amount of external energy inputs used in each scenario after having allocated the primary energy related to the inputs between the two energy services. The energy in the feedstock was not included in the external energy inputs. Direct combustion had the highest energy efficiency. It had energy ratios of 10 and 36 for electricity and heat, respectively. The least energy‐efficient scenario was the pyrolysis scenario where biochar was applied to soils. It had energy ratios of 4 and 12 for electricity and heat, respectively. The results showed that pyrolysis with carbon sequestration might be an option to counteract the current trend in global warming. The pyrolysis system with soil application of the biochar removed the largest amount of from the atmosphere. However, compared with the direct combustion scenario, the climate change mitigation potential depended on the energy system to which the bioenergy system delivered its energy services. A system expansion showed that direct combustion had the highest climate change mitigation potential when coal or natural gas were used as external energy sources to compensate for the lower energy efficiency of the pyrolysis scenario.     

Leukemia inhibitory factor induces apoptosis of the mammary epithelial cells and participates in mouse mammary gland involution

Leukemia inhibitory factor (LIF) is a multifunctional glycoprotein that displays multiple biological activities in different cell types, but to date there has been no report on its expression in the normal mammary gland. In this study we found that LIF is expressed at low but detectable levels in postpubertal, adult virgin, and pregnant mouse mammary glands. However, LIF expression drops after parturition to become almost undetectable in lactating glands. Interestingly, LIF expression shows a steep increase shortly after weaning that is maintained for the following 3 days. During this period, known as the first stage of mammary gland involution, the lack of suckling induces local factors that cause extensive epithelial cell death. It has been shown that Stat3 is the main factor in signaling the initiation of apoptosis, but the mechanism of its activation remains unclear. Herein, we show that LIF expression in the gland is induced by milk stasis and not by the decrease of circulating lactogenic hormones after weaning. Implantation of LIF containing pellets in lactating glands results in a significant increase in epithelium apoptosis. In addition, this treatment also induces Stat3 phosphorylation. We conclude that LIF regulated expression in the mouse mammary gland may play a relevant role during the first stage of mammary gland involution. Our results also show that LIF-induced mammary epithelium apoptosis could be mediated, at least partially, by Stat3 activation.     

Transmembrane topology of FRO2, a ferric chelate reductase from Arabidopsis thaliana

Iron uptake in Arabidopsis thaliana is mediated by ferric chelate reductase FRO2, a transmembrane protein belonging to the flavocytochrome b family. There is no high resolution structural information available for any member of this family. We have determined the transmembrane topology of FRO2 experimentally using the alkaline phosphatase fusion method. The resulting topology is different from that obtained by theoretical predictions and contains 8 transmembrane helices, 4 of which build up the highly conserved core of the protein. This core is present in the entire flavocytochrome b family. The large water soluble domain of FRO2, which contains NADPH, FAD and oxidoreductase sequence motifs, was located on the inside of the membrane.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at This work was supported by grants from the Swedish Research Council (VR) to S. Al-Karadaghi and Hans Hebert.     

AKAP350 modulates microtubule dynamics

AKAP350 is a multiply spliced type II protein kinase A-anchoring protein that localizes to the centrosomes in most cells and the Golgi apparatus in epithelial cells. Multiple studies suggest that AKAP350 is involved in microtubule nucleation at the centrosome. Our previous studies demonstrated that AKAP350 was necessary for the maintenance of Golgi apparatus integrity. These data suggested that AKAP350 might be necessary for normal cytoskeletal interactions with the Golgi. To examine the relationship of AKAP350 with the microtubule cytoskeleton, we analyzed the effect of the depletion of AKAP350 on microtubule regrowth after nocodazole treatment in HeLa cells. The decrease in AKAP350 expression with short interfering RNA induced a delay in microtubule elongation with no effect on microtubule aster formation. In contrast, overexpression of the centrosomal targeting domain of AKAP350 elicited alterations in aster formation, but did not affect microtubule elongation. RNA interference for AKAP350 also induced an increase in cdc42 activity during microtubule regrowth. Our data suggest that AKAP350 has a role in the remodeling of the microtubule cytoskeleton.     

Abscisic acid-triggered guard cell l-cysteine desulfhydrase function and in situ hydrogen sulfide production contributes to heme oxygenase-modulated stomatal closure

Recent studies have demonstrated that hydrogen sulfide (H₂S) produced through the activity of l -cysteine desulfhydrase (DES1) is an important gaseous signaling molecule in plants that could participate in abscisic acid (ABA)-induced stomatal closure. However, the coupling of the DES1/H₂S signaling pathways to guard cell movement has not been thoroughly elucidated. The results presented here provide genetic evidence for a physiologically relevant signaling pathway that governs guard cell in situ DES1/H₂S function in stomatal closure. We discovered that ABA-activated DES1 produces H₂S in guard cells. The impaired guard cell ABA phenotype of the des1 mutant can be fully complemented when DES1/H₂S function has been specifically rescued in guard cells and epidermal cells, but not mesophyll cells. This research further characterized DES1/H₂S function in the regulation of LONG HYPOCOTYL1 (HY1, a member of the heme oxygenase family) signaling. ABA-induced DES1 expression and H₂S production are hyper-activated in the hy1 mutant, both of which can be fully abolished by the addition of H₂S scavenger. Impaired guard cell ABA phenotype of des1/hy1 can be restored by H₂S donors. Taken together, this research indicated that guard cell in situ DES1 function is involved in ABA-induced stomatal closure, which also acts as a pivotal hub in regulating HY1 signaling.