On the ftight capabilities and distribution of the giant Miocene bird Argentavis magnificens (Teratornithidae)

Argentavis magnificens , the largest known flying bird, had a wingspan of over 6 m with a mass of 80 kg. Its enormous size suggests that it was not a powerful flapper. The wing shape is inferred as more like that of large extant birds that soar relatively slowly on thermals over land than of large pelagic birds that soar over water. Its high wing loading would have allowed it to fly in moderate to strong winds that must have been prohibitive for the largest known contemporary thermal soarers. The high wing loading would have been ill-suited to flight under poor thermal conditions, but it would have been useful in slope-soaring on uprising air current against hillsides. We propose that Argentavis had a large home range that included a nesting area in the mountains of western and northwestern Argentina, and a feeding area in the Pampas.     

ESR Resolves the C Terminus Structure of the Ligand-free Human Glutathione S-Transferase A1-1

Nitroxide- and Cu²⁺-based electron spin resonance (ESR) are combined to provide insight into the conformational states of the functionally important α-helix of the human glutathione S-transferase A1. Distance measurements on various spin-labeled dimeric human glutathione S-transferase A1-1 all result in bimodal distance distributions, indicating that the C-terminus exists in two distinct conformations in solution, one of which closely matches that found in the crystal structure of the ligand-bound enzyme. These measurements permit the generation of a model of the unliganded conformation. Room temperature ESR indicates that the second conformation has high mobility, potentially enabling the enzyme’s high degree of substrate promiscuity. This model is then validated using computational modeling and further Cu²⁺-based ESR distance measurements. Cu²⁺-based ESR also provides evidence that the secondary structure of the second conformation is of helical nature. Addition of S-hexyl glutathione results in a shift in relative populations, favoring the state that is similar to the previously known structure of the ligand-bound enzyme.     

A variable light domain fluorogen activating protein homodimerizes to activate dimethylindole red

Novel fluorescent tools such as green fluorescent protein analogues and fluorogen activating proteins (FAPs) are useful in biological imaging for tracking protein dynamics in real time with a low fluorescence background. FAPs are single-chain variable fragments (scFvs) selected from a yeast surface display library that produce fluorescence upon binding a specific dye or fluorogen that is normally not fluorescent when present in solution. FAPs generally consist of human immunoglobulin variable heavy (V(H)) and variable light (V(L)) domains covalently attached via a glycine- and serine-rich linker. Previously, we determined that the yeast surface clone, V(H)-V(L) M8, could bind and activate the fluorogen dimethylindole red (DIR) but that the fluorogen activation properties were localized to the M8V(L) domain. We report here that both nuclear magnetic resonance and X-ray diffraction methods indicate the M8V(L) forms noncovalent, antiparallel homodimers that are the fluorogen activating species. The M8V(L) homodimers activate DIR by restriction of internal rotation of the bound dye. These structural results, together with directed evolution experiments with both V(H)-V(L) M8 and M8V(L), led us to rationally design tandem, covalent homodimers of M8V(L) domains joined by a flexible linker that have a high affinity for DIR and good quantum yields.     

Exploring purine N7 interactions via atomic mutagenesis: the group I ribozyme as a case study

Atomic mutagenesis has emerged as a powerful tool to unravel specific interactions in complex RNA molecules. An early extensive study of analogs of the exogenous guanosine nucleophile in group I intron self-splicing by Bass and Cech demonstrated structure-function relationships analogous to those seen for protein ligands and provided strong evidence for a well-formed substrate binding site made of RNA. Subsequent functional and structural studies have confirmed these interacting sites and extended our understanding of them, with one notable exception. Whereas 7-methyl guanosine did not affect reactivity in the original study, a subsequent study revealed a deleterious effect of the seemingly more conservative 7-deaza substitution. Here we investigate this paradox, studying these and other analogs with the more thoroughly characterized ribozyme derived from the Tetrahymena group I intron. We found that the 7-deaza substitution lowers binding by ~20-fold, relative to the cognate exogenous guanosine nucleophile, whereas binding and reaction with 7-methyl and 8-aza-7-deaza substitutions have no effect. These and additional results suggest that there is no functionally important contact between the N7 atom of the exogenous guanosine and the ribozyme. Rather, they are consistent with indirect effects introduced by the N7 substitution on stacking interactions and/or solvation that are important for binding. The set of analogs used herein should be valuable in deciphering nucleic acid interactions and how they change through reaction cycles for other RNAs and RNA/protein complexes.     

Aberrant energy-linked reactions in mitochondria isolated from the livers of sheep infected with the liver fluke Fasciola hepatica

Respiration by mitochondria isolated from the livers of sheep following infection up to 15 weeks with F. hepatica was measured with the respiratory substrates pyruvate (plus malate) and succinate in the absence and presence of ADP; the rates were compared with those obtained by mitochondria isolated from livers of uninfected sheep. It was found that respiration supported by both substrates in mitochondria isolated from the left lobe but not the middle lobe of 4-week infected sheep exhibited abnormalities such that the acceptor control ratios were only marginally above one. Some, but not total, recovery was seen in the later stages of infection. The aberrant respiratory behaviour is similar to that observed with infected rats.     

可溶性细胞间粘附分子在慢性肾脏病中的变化

目的:研究慢性肾病(CKD)患者血清可溶性细胞粘附分子-1(soluble intercellular adhesionmolecule-1,sICAM)的变化与临床意义。方法:用双抗体夹心ELISA方法,对52例CKD患者及20例健康对照人群的sICAM-1水平进行检测分析。52例CKD患者中,其中27例为CRF血液透析患者;25例肾功能正常CKD患者。结果:CKD组患者sICAM-1水平明显高于对照组(105.42±61.95)(P<0.01);肾功能正常CKD组和CKD-CRF组sICAM-1水平均显著高于对照组(P<0.01);CRF组sICAM-1水平明显低于肾功能正常CKD组(P<0.01);但高于对照组(84.80±19.61/164.08±70.66/54.61±5.48)(P<0.01)。结论:sICAM-1水平在慢性肾脏病中明显升高,CRF组病人sICAM-1水平低于CKD肾功能正常患者,提示透析过程中可能有sICAM溢出,吸附并丢失入透析液中(1),或可能是肾纤维化为主的病变使sICAM-1表达下降。     

Artificial substrata in a shallow sublittoral habitat: do they adequately represent natural habitats or the local species pool?

Artificial substrata have been advocated as tools which have considerable potential for monitoring both natural and anthropogenic effects on invertebrate communities of shallow coastal environments. In this experiment, community structure was compared between two dominant natural algal habitats (kelp holdfasts and algal turf) and artificial substratum units (ASUs; nests of pan scourers) deployed in close contact with, and 20 cm above the substratum. Univariate and multivariate statistical analyses were applied to the data to determine the similarity of community structure between the four different habitats. In addition, recently developed measures of taxonomic distinctness were applied to the data from both sets of artificial substrata to determine if they provided a representative sample of the local epifaunal species pool and thus have the potential to be used as surrogate samples for this important faunal group. There were marked differences between community structure in each of the habitats. Both sets of artificial substrata were dominated by tubicolous polychaetes with abundances that were more than an order of magnitude greater than in the holdfast and turf samples. The fauna recruiting to the artificial substrata deployed above the substratum showed the lowest values in the univariate summaries of diversity and evenness and were unrepresentative of the local species pool. Artificial samples deployed in contact with the substratum showed greater diversity and evenness but were still mostly unrepresentative of the local species pool. The tendency for both sets of artificial substrata to under-sample amphipods and to be dominated by suspension-feeding polychaetes suggests that methods using these units may be relatively insensitive to the effects of anthropogenic impacts (e.g. sewage outfalls) where shifts in community structure including increased dominance of suspension-feeders and polychaetes and a reduced dominance of amphipods have been observed. Further studies, including the evaluation of temporal variation in community structure related to the time at which the ASUs are deployed and duration of deployment, are needed to test the wider utility of artificial substrata as tools for monitoring shallow, sublittoral, epifaunal communities.     

Observational study of lenalidomide in patients with mantle cell lymphoma who relapsed/progressed after or were refractory/intolerant to ibrutinib (MCL-004)

Background

The observational MCL-004 study evaluated outcomes in patients with relapsed/refractory mantle cell lymphoma who received lenalidomide-based therapy after ibrutinib failure or intolerance.

Methods

The primary endpoint was investigator-assessed overall response rate based on the 2007 International Working Group criteria.

Results

Of 58 enrolled patients (median age, 71 years; range, 50–89), 13 received lenalidomide monotherapy, 11 lenalidomide plus rituximab, and 34 lenalidomide plus other treatment. Most patients (88%) had received ≥?3 prior therapies (median 4; range, 1–13). Median time from last dose of ibrutinib to the start of lenalidomide was 1.3 weeks (range, 0.1–21.7); 45% of patients had partial responses or better to prior ibrutinib. Primary reasons for ibrutinib discontinuation were lack of efficacy (88%) and ibrutinib toxicity (9%). After a median of two cycles (range, 0–11) of lenalidomide-based treatment, 17 patients responded (8 complete responses, 9 partial responses), for a 29% overall response rate (95% confidence interval, 18–43%) and a median duration of response of 20 weeks (95% confidence interval, 2.9 to not available). Overall response rate to lenalidomide-based therapy was similar for patients with relapsed/progressive disease after previous response to ibrutinib (i.e., ≥PR) versus ibrutinib-refractory (i.e., ≤SD) patients (30 versus 32%, respectively). The most common all-grade treatment-emergent adverse events after lenalidomide-containing therapy (n = 58) were fatigue (38%) and cough, dizziness, dyspnea, nausea, and peripheral edema (19% each). At data cutoff, 28 patients have died, primarily due to mantle cell lymphoma.

Conclusion

Lenalidomide-based treatment showed clinical activity, with no unexpected toxicities, in patients with relapsed/refractory mantle cell lymphoma who previously failed ibrutinib therapy.

Trial registration

Clinicaltrials.gov identifier NCT02341781. Date of registration: January 14, 2015