When Indian crabs were not yet Asian - biogeographic evidence for Eocene proximity of India and Southeast Asia

Background  

The faunal and floral relationship of northward-drifting India with its neighboring continents is of general biogeographic interest as an important driver of regional biodiversity. However, direct biogeographic connectivity of India and Southeast Asia during the Cenozoic remains largely unexplored. We investigate timing, direction and mechanisms of faunal exchange between India and Southeast Asia, based on a molecular phylogeny, molecular clock-derived time estimates and biogeographic reconstructions of the Asian freshwater crab family Gecarcinucidae.     

Cooling of pacu (Piaractus mesopotamicus) embryos at various stages of development for 6 or 10 hours

The objective of this research was to verify the effects of cooling embryos of pacu, Piaractus mesopotamicus, in four stages of development during two stocking periods. The stages of embryo development were at: blastoderm, ∼64 cells—1.4 h after fertilization (haf); 25% of the epiboly movement—5.2 haf; blastoporous closing—8.0 haf; and optical vesicle appearing—13.3 haf. Embryos were exposed to a cryoprotectant solution containing methanol (10%) and sucrose (0.5 M). Thereafter, embryos were submitted to a cooling curve until they reached −8 °C, and then kept cooled for 6 or 10 h. In addition, for each stage of embryonic development, a control group with uncooled embryos was used to compare hatching rates. The total number of larvae from the first two stages of ontogenetic development (1.4 and 5.2 haf) was lower compared to the other stages (0.0 and 8.0 haf). There was no significant difference between stages 8.0 and 13.3 haf for the total number of larvae (49.9 ± 6.7% and 55.2 ± 6.7%, respectively). Embryo diameter varied according to embryonic stage, providing evidence of differences in membrane permeability. There was a negative correlation between embryo diameter and the total number of larvae (r = −0.372). In conclusion, use of embryonic stages 8.0 and 13.3 haf were recommended for maintaining cooled pacu embryos at −8 °C for 6 or 10 h.     

Harvesting of novel polyhydroxyalkanaote (PHA) synthase encoding genes from a soil metagenome library using phenotypic screening

Salmonella enterica serovar Typhi and Typhimurium are closely related serovars. However, S. Typhi, a human-specific pathogen, has 5% of genes as pseudogenes, far more than S. Typhimurium, which only has 1%. One of these pseudogenes corresponds to sopD2, which in S. Typhimurium encodes an effector protein involved in Salmonella-containing vacuole biogenesis in human epithelial cell lines, which is needed for full virulence of the pathogen. We investigated whether S. Typhi trans-complemented with the functional sopD2 gene from S. Typhimurium (sopD2(STM) ) would reduce the invasion of human epithelial cell lines. Our results showed that the presence of sopD2(STM) in S. Typhi significantly modified the bacterial ability to alter cellular permeability and decrease the CFUs recovered after cell invasion of human epithelial cell line. These results add to mounting evidence that pseudogenes contribute to S. Typhi adaptation to humans.     

Subclinical inflammation on MRI of hand and foot of anticitrullinated peptide antibody–negative arthralgia patients at risk for rheumatoid arthritis

Introduction

It is known that anticitrullinated peptide antibody (ACPA)–positive rheumatoid arthritis (RA) has a preclinical phase. Whether this phase is also present in ACPA-negative RA is unknown. To determine this, we studied ACPA-negative arthralgia patients who were considered prone to progress to RA for local subclinical inflammation observed on hand and foot magnetic resonance imaging (MRI) scans.

Methods

We studied a total of 64 ACPA-negative patients without clinically detectable arthritis and with arthralgia of the small joints within the previous 1 year. Because of the character of the patients’ symptoms, the rheumatologists considered these patients to be prone to progress to RA. For comparisons, we evaluated 19 healthy, symptom-free controls and 20 ACPA-negative RA patients, who were identified according to the 1987 American Rheumatism Association criteria. All participants underwent MRI of unilateral wrist, metacarpophalangeal and metatarsophalangeal joints. Synovitis and bone marrow oedema (BME) were scored according to the OMERACT rheumatoid arthritis magnetic resonance imaging scoring system, and the scores were summed to yield the ‘MRI inflammation score’. Scores were compared between groups. Among the ACPA-negative arthralgia patients, MRI inflammation scores were related to C-reactive protein (CRP) levels and the tenderness of scanned joints.

Results

MRI inflammation scores increased progressively among the groups of controls and ACPA-negative arthralgia and RA patients (median scores = 0, 1 and 10, respectively; P < 0.001). The MRI inflammation scores of ACPA-negative arthralgia patients were significantly higher than those of controls (P = 0.018). In particular, the synovitis scores were higher in ACPA-negative arthralgia patients (P = 0.046). Among the ACPA-negative arthralgia patients, inflammation was observed predominantly in the wrist (53%). The synovitis scores were associated with CRP levels (P = 0.007) and joint tenderness (P = 0.026). Despite the limited follow-up duration, five patients developed clinically detectable arthritis. These five patients had higher scores for MRI inflammation (P = 0.001), synovitis (P = 0.002) and BME (P = 0.003) compared to the other patients.

Conclusion

Subclinical synovitis was observed in the small joints of ACPA-negative arthralgia patients, and especially in patients whose conditions progressed to clinically detectable arthritis. This finding suggests the presence of a preclinical phase in ACPA-negative RA. Further longitudinal studies of these lesions and patients are required to confirm this hypothesis.     

A genetic variant in osteoprotegerin is associated with progression of joint destruction in rheumatoid arthritis

Introduction

Progression of joint destruction in rheumatoid arthritis (RA) is partly heritably; 45 to 58% of the variance in joint destruction is estimated to be explained by genetic factors. The binding of RANKL (Receptor Activator for Nuclear Factor κ B Ligand) to RANK results in the activation of TRAF6 (tumor necrosis factor (TNF) receptor associated factor-6), and osteoclast formation ultimately leading to enhanced bone resorption. This bone resorption is inhibited by osteoprotegerin (OPG) which prevents RANKL-RANK interactions. The OPG/RANK/RANKL/TRAF6 pathway plays an important role in bone remodeling. Therefore, we investigated whether genetic variants in OPG, RANK, RANKL and TRAF6 are associated with the rate of joint destruction in RA.

Methods

1,418 patients with 4,885 X-rays of hands and feet derived from four independent data-sets were studied. In each data-set the relative increase of the progression rate per year in the presence of a genotype was assessed. First, explorative analyses were performed on 600 RA-patients from Leiden. 109 SNPs, tagging OPG, RANK, RANKL and TRAF6, were tested. Single nucleotide polymorphisms (SNPs) significantly associated in phase-1 were genotyped in data-sets from Groningen (Netherlands), Sheffield (United Kingdom) and Lund (Switzerland). Data were summarized in an inverse weighted variance meta-analysis. Bonferonni correction for multiple testing was applied.

Results

We found that 33 SNPs were significantly associated with the rate of joint destruction in phase-1. In phase-2, six SNPs in OPG and four SNPs in RANK were associated with progression of joint destruction with P-value <0.05. In the meta-analyses of all four data-sets, RA-patients with the minor allele of OPG-rs1485305 expressed higher rates of joint destruction compared to patients without these risk variants (P = 2.35x10⁻⁴). This variant was also significant after Bonferroni correction.

Conclusions

These results indicate that a genetic variant in OPG is associated with a more severe rate of joint destruction in RA.     

Lectin staining of sheep microglia

The B₄-isolectin from Griffonia simplicifolia is known to stain microglial cells in a variety of species. The present report describes a lectin staining method that has been modified to facilitate staining of resting microglia, as well as perivascular cells, in vibratome sections of normal sheep brain. This modified method employs tissue fixed in formaldehyde or paraformaldehyde and requires incubating sections with Triton X-100 prior to staining.     

Hydroxycinnamoyl amides in stem explants from flowering and non-flowering Nicotiana tabacum

Flower formation in stem explants was chosen as an experimental system for the study of the function of hydroxycinnamoyl amides (HCAs) in plants. The explants, derived from flowering and non-flowering Nicotiana tabacum L. var. Xanthi nc., differentiated to two types of callus and afterwards to flower buds. A novel reversed-phase high performance liquid chromatography method, following sample clean-up on CM-Fractogel columns, enabled us to examine HCA concentrations in small tissue samples. Two different groups of HCA could be distinguished during in vitro flower formation: Firstly, feruloyl- and diferuloyputrescine, the major detectable HCAs that accumulated during callus proliferation; secondly, caffeoylputrescine, which accumulated during the later stage of flower differentiation and reached higher concentrations than feruloylputrescine.     

Pronounced species turnover,but no functional equivalence in leaf consumption of invasive amphipods in the river Rhine

A growing body of literature focuses on the adverse effects of biological invasions, e.g., on the decline of indigenous biodiversity, while studies on the consequences of invasions on components of ecosystem functioning are comparatively rare. Owing to their leaf shredding activity, amphipods play a fundamental role in determining energy flow dynamics in Central European freshwater ecosystems, but whether the dramatic change in species composition after the invasion of Ponto–Caspian taxa affects this process has not been addressed in a comprehensive study. In a laboratory experiment we determined consumption rates of three leaf types (Alnus glutinosa, Betula pendula, Quercus robur) from common riparian arboreal vegetation in the Rhine drainage—one of the most heavily invaded river systems worldwide—by the most common native (Gammarus fossarum, G. pulex, G. roeselii) and invasive amphipods (Dikerogammarus villosus, Echinogammarus ischnus). Leaf-shredding activity was significantly lower in invasive than in native amphipods across leaf types, and a subsequent analysis ruled out an effect of different metabolic rates as an explanation. Another experiment was motivated by the observation that native amphipods are nowadays restricted to smaller tributaries to the Rhine, while invasive taxa are dominant in the main channel. As leaf litter shredding may be more important in headwaters than in lower parts of streams, we sought for a signature of within-species variation in the feeding ecology of amphipods and thus compared two different populations of G. pulex, but found very similar leaf consumption rates in upstream and downstream populations, suggesting that food preferences in amphipods could be species-specific with little potential for microevolution or environmentally induced plasticity. In conclusion, the rapid replacement of native amphipod species in the Rhine drainage likely affects vital ecosystem services, with the potential to change the aquatic food web (e.g., through reduced shredding activity and hence, reduced resource availability for particle-feeding detritivores), unless other taxonomic groups compensate for those functional alterations.     

Cardiac Effects of Attenuating Gsα - Dependent Signaling

Aims

Inhibition of β-adrenergic signalling plays a key role in treatment of heart failure. Gsα is essential for β-adrenergic signal transduction. In order to reduce side-effects of beta-adrenergic inhibition diminishing β-adrenergic signalling in the heart at the level of Gsα is a promising option.

Methods and Results

We analyzed the influence of Gsα on regulation of myocardial function and development of cardiac hypertrophy, using a transgenic mouse model (C57BL6/J mice) overexpressing a dominant negative Gsα-mutant under control of the α-MHC-promotor. Cardiac phenotype was characterized in vivo and in vitro and under acute and chronic β-adrenergic stimulation. At rest, Gsα-DN-mice showed bradycardia (602 ± 13 vs. 660 ± 17 bpm, p<0.05) and decreased dp/dt_max (5037 ± 546- vs. 6835 ± 505 mmHg/s, p = 0.02). No significant differences were found regarding ejection fraction, heart weight and cardiomyocyte size. β-blockade by propranolol revealed no baseline differences of hemodynamic parameters between wildtype and Gsα-DN-mice. Acute adrenergic stimulation resulted in decreased β-adrenergic responsiveness in Gsα-DN-mice. Under chronic adrenergic stimulation, wildtype mice developed myocardial hypertrophy associated with increase of LV/BW-ratio by 23% (4.4 ± 0.2 vs. 3.5 ± 0.1 mg/g, p<0.01) and cardiac myocyte size by 24% (14927 ± 442 px vs. 12013 ± 583 px, p<0.001). In contrast, both parameters were unchanged in Gsα-DN-mice after chronic isoproterenol stimulation.

Conclusion

Overexpression of a dominant negative mutant of Gsα leads to decreased β-adrenergic responsiveness and is protective against isoproterenol-induced hypertrophy. Thus, Gsα-DN-mice provide novel insights into β-adrenergic signal transduction and its modulation in myocardial overload and failure.