Intrinsic vs. extrinsic influences on life history expression: metabolism and parentally induced temperature influences on embryo development rate

Intrinsic processes are assumed to underlie life history expression and trade‐offs, but extrinsic inputs are theorised to shift trait expression and mask trade‐offs within species. Here, we explore application of this theory across species. We do this based on parentally induced embryo temperature as an extrinsic input, and mass‐specific embryo metabolism as an intrinsic process, underlying embryonic development rate. We found that embryonic metabolism followed intrinsic allometry rules among 49 songbird species from temperate and tropical sites. Extrinsic inputs via parentally induced temperatures explained the majority of variation in development rates and masked a relationship with metabolism; metabolism explained a minor proportion of the variation in development rates among species, and only after accounting for temperature effects. We discuss evidence that temperature further obscures the expected interspecific trade‐off between development rate and offspring quality. These results demonstrate the importance of considering extrinsic inputs to trait expression and trade‐offs across species.     

In-situ localization of chalcone synthase mRNA in pea root nodule development

In this paper studies on the role of flavonoids in pea root nodule development are reported. Flavonoid synthesis was followed by localizing chalcone synthase (CHS) mRNA in infected pea roots and in root nodules. In a nodule primordium, CHS mRNA is present in all cells of the primordium. Therefore it is hypothesized that the Rhizobium Nod factor induces cell division in the root cortex by stimulating the production of flavonoids that function as auxin transport inhibitors. In nodules CHS mRNA is predominantly present in a region at the apex of the nodule consisting of meristematic and cortical cells. These cells are not infected by Rhizobium. Therefore it is postulated that CHS plays a role in nodule development rather than in a defence response. In roots CHS mRNA is located at a similar position as in nodules, suggesting that CHS has the same function in both root and nodule development. When nodules are formed by mutants of Rhizobium leguminosarum bv. viciae that are unable to secrete β(1-2) glucan and to synthesize the O-antigen containing LPS I, CHS genes are also expressed in regions of the nodule that are infected by Rhizobium. It is postulated that the impaired development of nodules formed by these mutants is due to an induction of a plant defence response.     

Symmetrical effect of pre-exposure between alcohol and morphine on conditioned taste aversion

It has previously been reported that pre-exposure to a psychoactive drug can block the conditioned taste aversion associated with that drug. This study was an attempt to investigate alcohol-morphine interactions using this pre-exposure paradigm. After two weeks of adaptation to a schedule of daily 30-minute access to water, rats were pre-exposed to morphine, ethanol, or the respective vehicle control every second day for three days before (Days 1, 3, 5) and after the first conditioning day (Days 8, 10, 12). On conditioning days (Days 7, 14), animals were first presented with a saccharin solution for 30 minutes following which animals that were pre-exposed to morphine were injected with ethanol while those pre-exposed to ethanol were administered with morphine. Saccharin was again presented on three more occasions (Days 21, 28, 35) without drug injection. Using the percent change in saccharin consumed from the first presentation as a measure of aversion, it was found that pre-exposure to morphine blocked ethanol conditioned taste aversion. Similarly, animals pre-exposed to ethanol showed less aversion to the saccharin paired with morphine. This is the first demonstration of a symmetrical relationship between alcohol and the opiates.     

The phenotype of some late-flowering mutants is enhanced by a locus on chromosome 5 that is not effective in the Landsberg erecta wild-type

Late-flowering mutants that have been described in ecotypes other than Landsberg erecta (Ler) have been found to be dominant alleles of the FRI locus located on chromosome 4, which determines lateness in many very late ecotypes. The extreme lateness of dominant FRI alleles depends on dominant alleles at the FLC locus that maps on the top of chromosome 5. FLC alleles with this effect have been found in all ecotypes tested (Col, Ws, S96, Est and Li) except Ler. Most likely the same locus confers lateness to the luminidependens (ld) mutant. Genotypes with a dominant FRI allele and the monogenic recessive ld mutant are only slightly later with recessive Ler alleles at the FLC locus. Genotypes where the dominant FLC alleles are combined with FRI or with the ld mutant, are strongly responsive to vernalization, which is much less effective in the FLC-Ler background.     

Bone marrow-derived mesenchymal stromal cells from patients with end-stage renal disease are suitable for autologous therapy

Background aimsMesenchymal stromal cells (MSCs) are pluripotent cells that have immunosuppressive and reparative properties in vitro and in vivo. Although autologous bone marrow (BM)-derived MSCs are already clinically tested in transplant recipients, it is unclear whether these BM cells are affected by renal disease. We assessed whether renal failure affected the function and therapeutic potential of BM-MSCs.MethodsMSCs from 10 adults with end-stage renal disease (ESRD) and 10 age-matched healthy controls were expanded from BM aspirates and tested for phenotype and functionality in vitro.ResultsMSCs from ESRD patients were >90% positive for CD73, CD90 and CD105 and negative for CD34 and CD45 and showed a similar morphology and differentiation capacity as MSCs from healthy controls. Of importance for their clinical utility, growth characteristics were similar in both groups, and sufficient numbers of MSCs were obtained within 4 weeks. Messenger RNA expression levels of self-renewal genes and factors involved in repair and inflammation were also comparable between both groups. Likewise, microRNA expression profiling showed a broad overlap between ESRD and healthy donor MSCs. ESRD MSCs displayed the same immunosuppressive capacities as healthy control MSCs, demonstrated by a similar dose-dependent inhibition of peripheral blood mononuclear cell proliferation, similar inhibition of proinflammatory cytokines tumor necrosis factor-α and interferon-γ production and a concomitant increase in the production of interleukin-10.ConclusionsExpanded BM-MSCs procured from ESRD patients and healthy controls are both phenotypically and functionally similar. These findings are important for the potential autologous clinical application of BM-MSCs in transplant recipients.     

Magnesium deficiency results in an increased formation of osteoclasts

Magnesium (Mg²⁺) deficiency is a frequently occurring disorder that leads to loss of bone mass, abnormal bone growth and skeletal weakness. It is not clear whether Mg²⁺ deficiency affects the formation and/or activity of osteoclasts. We evaluated the effect of Mg²⁺ restriction on these parameters. Bone marrow cells from long bone and jaw of mice were seeded on plastic and on bone in medium containing different concentrations of Mg²⁺ (0.8 mM which is 100% of the normal value, 0.4, 0.08 and 0 mM). The effect of Mg²⁺ deficiency was evaluated on osteoclast precursors for their viability after 3 days and proliferation rate after 3 and 6 days, as was mRNA expression of osteoclastogenesis-related genes and Mg²⁺-related genes. After 6 days of incubation, the number of tartrate resistant acid phosphatase-positive (TRACP⁺) multinucleated cells was determined, and the TRACP activity of the medium was measured. Osteoclastic activity was assessed at 8 days by resorption pit analysis. Mg²⁺ deficiency resulted in increased numbers of osteoclast-like cells, a phenomenon found for both types of marrow. Mg²⁺ deficiency had no effect on cell viability and proliferation. Increased osteoclastogenesis due to Mg²⁺ deficiency was reflected in higher expression of osteoclast-related genes. However, resorption per osteoclast and TRACP activity were lower in the absence of Mg²⁺. In conclusion, Mg²⁺ deficiency augmented osteoclastogenesis but appeared to inhibit the activity of these cells. Together, our in vitro data suggest that altered osteoclast numbers and activity may contribute to the skeletal phenotype as seen in Mg²⁺ deficient patients.     

CT Coronary Angiography Is Feasible for the Assessment of Coronary Artery Disease in Chronic Dialysis Patients,Despite High Average Calcium Scores

Purpose

Significant obstructive coronary artery disease (CAD) is common in asymptomatic dialysis patients. Identifying these high risk patients is warranted and may improve the prognosis of this vulnerable patient group. Routine catheterization of incident dialysis patients has been proposed, but is considered too invasive. CT-angiography may therefore be more appropriate. However, extensive coronary calcification, often present in this patient group, might hamper adequate lumen evaluation. The objective of this study was to assess the feasibility of CT-angiography in this patient group.

Methods

For this analysis all patients currently participating in the ICD2 trial (ISRCTN20479861), with no history of PCI or CABG were included. The major epicardial vessels were evaluated on a segment basis (segment 1–3, 5–8, 11 and 13) by a team consisting of an interventional and an imaging specialist. Segments were scored as not significant, significant and not interpretable.

Results

A total of 70 dialysis patients, with a mean age of 66±8 yrs and predominantly male (70%) were included. The median calcium score was 623 [79, 1619].Over 90% of the analyzed segments were considered interpretable. The incidence of significant CAD on CT was 43% and was associated with cardiovascular events during follow-up. The incidence of cardiovascular events after 2-years follow-up: 36% vs. 0% in patients with no significant CAD (p<0.01).

Conclusion

Despite the high calcium scores CT-angiography is feasible for the evaluation of the extent of CAD in dialysis patients. Moreover the presence of significant CAD on CT was associated with events during follow-up.