A dubious defense of ‘after‐birth abortion’: A reply to Räsänen

Scholars have offered various critiques of Alberto Giubilini and Francesca Minerva's controversial article, ‘After‐birth abortion: Why should the baby live?’ My book The Ethics of Abortion: Women's Rights, Human Life, and the Question of Justice presents four such critiques. First, Giubilini and Minerva argue from the deeply controversial to the even more controversial. Second, they presuppose a false view of personal identity called body‐self dualism. Third, their view cannot secure human equality. And fourth, their account of harm cannot account for harm found in some cases of murder. In the article, ‘Pro‐life arguments against infanticide and why they are not convincing’, J. Räsänen examines and finds wanting these four critiques. This essay responds to Räsänen's defense of infanticide and argues that his responses to the four objections fail.     

YcfDRM is a thermophilic oxygen-dependent ribosomal protein uL16 oxygenase

Extremophiles - YcfD from Escherichia coli is a homologue of the human ribosomal oxygenases NO66 and MINA53, which catalyse histidyl-hydroxylation of the 60S subunit and affect cellular...     

Reduction in neuronal L-type calcium channel activity in a double knock-in mouse model of Alzheimer's disease

Increased function of neuronal L-type voltage-sensitive Ca^2 + channels (L-VSCCs) is strongly linked to impaired memory and altered hippocampal synaptic plasticity in aged rats. However, no studies have directly assessed L-VSCC function in any of the common mouse models of Alzheimer's disease where neurologic deficits are typically more robust. Here, we used cell-attached patch-clamp recording techniques to measure L-VSCC activity in CA1 pyramidal neurons of partially dissociated hippocampal “zipper” slices prepared from 14-month-old wild-type mice and memory-impaired APP/PS1 double knock-in mice. Surprisingly, the functional channel density of L-VSCCs was significantly reduced in the APP/PS1 group. No differences in voltage dependency and unitary conductance of L-VSCCs were observed. The results suggest that mechanisms for Ca^2 + dysregulation can differ substantially between animal models of normal aging and models of pathological aging.     

Solution conformation of laminaribioside and (1 → 3)-β-D-glucan from optical rotation

A chiroptical method of conformational analysis is applied to linear (1 → 3)-β-D -glucans and the dimeric analogues β- and α-laminaribioside. The method is based on a recently developed semiempirical calculational model for saccharide optical activity. We conclude that disaccharide conformational energy maps in the literature represent the effective potential energy surface in aqueous solution well. The positive optical rotation observed with long chains in dilute alkaline solution is not characteristic of any single–chain conformation, and must reflect chain association.     

Voltage dependence of subthreshold resonance frequency in layer II of medial entorhinal cortex

The resonance properties of individual neurons in entorhinal cortex (EC) may contribute to their functional properties in awake, behaving rats. Models propose that entorhinal grid cells could arise from shifts in the intrinsic frequency of neurons caused by changes in membrane potential owing to depolarizing input from neurons coding velocity. To test for potential changes in intrinsic frequency, we measured the resonance properties of neurons at different membrane potentials in neurons in medial and lateral EC. In medial entorhinal neurons, the resonant frequency of individual neurons decreased in a linear manner as the membrane potential was depolarized between -70 and -55 mV. At more hyperpolarized membrane potentials, cells asymptotically approached a maximum resonance frequency. Consistent with the previous studies, near resting potential, the cells of the medial EC possessed a decreasing gradient of resonance frequency along the dorsal to ventral axis, and cells of the lateral EC lacked resonant properties, regardless of membrane potential or position along the medial to lateral axis within lateral EC. Application of 10 μM ZD7288, the H-channel blocker, abolished all resonant properties in MEC cells, and resulted in physiological properties very similar to lateral EC cells. These results on resonant properties show a clear change in frequency response with depolarization that could contribute to the generation of grid cell firing properties in the medial EC.     

Translational control of gurken mRNA in Drosophila development

Localized mRNA translation is a widespread mechanism for targeting protein synthesis, important for cell fate, motility and pathogenesis. In Drosophila, the spatiotemporal control of gurken/TGF-α mRNA translation is required for establishing the embryonic body axes. A number of recent studies have highlighted key aspects of the mechanism of gurken mRNA translational control at the dorsoanterior corner of the mid-stage oocyte. Orb/CPEB and Wispy/GLD-2 are required for polyadenylation of gurken mRNA, but unlocalized gurken mRNA in the oocyte is not fully polyadenylated.¹ Norvell A, Wong J, Randolph K, Thompson L. Wispy and Orb cooperate in the cytoplasmic polyadenylation of localized gurken mRNA. Dev Dyn Off Publ Am Assoc Anat 2015; 244:1276-1285. [Google Scholar] At the dorsoanterior corner, Orb and gurken mRNA have been shown to be enriched at the edge of Processing bodies, where translation occurs.² Weil TT, Parton RM, Herpers B, Soetaert J, Veenendaal T, Xanthakis D, Dobbie IM, Halstead JM, Hayashi R, Rabouille C, et al. Drosophila patterning is established by differential association of mRNAs with P bodies. Nat Cell Biol 2012; 14:1305-1313; PMID:23178881; http://dx.doi.org/10.1038/ncb2627[Crossref], [PubMed], [Web of Science ®] [Google Scholar] Over-expression of Orb in the adjacent nurse cells, where gurken mRNA is transcribed, is sufficient to cause mis-expression of Gurken protein.³ Davidson A, Parton RM, Rabouille C, Weil TT, Davis I. Localized translation of gurken/TGF-α mRNA during axis specification is controlled by access to Orb/CPEB on processing bodies. Cell Rep 2016; 14:2451-2462; PMID:26947065; http://dx.doi.org/10.1016/j.celrep.2016.02.038[Crossref], [PubMed], [Web of Science ®] [Google Scholar] In orb mutant egg chambers, reducing the activity of CK2, a Serine/Threonine protein kinase, enhances the ventralized phenotype, consistent with perturbation of gurken translation.⁴ Wong LC, Costa A, McLeod I, Sarkeshik A, Yates J 3rd, Kyin S, Perlman D, Schedl P, et al. The functioning of the drosophila CPEB protein Orb is regulated by phosphorylation and requires casein kinase 2 activity. PLoS One 2011; 6:e24355; PMID:21949709; http://dx.doi.org/10.1371/journal.pone.0024355[Crossref], [PubMed], [Web of Science ®] [Google Scholar] Here we show that sites phosphorylated by CK2 overlap with active Orb and with Gurken protein expression. Together with our new findings we consolidate the literature into a working model for gurken mRNA translational control and review the role of kinases, cell cycle factors and polyadenylation machinery highlighting a multitude of conserved factors and mechanisms in the Drosophila egg chamber.     

The photoprotective molecular switch in the photosystem II antenna

We have reviewed the current state of multidisciplinary knowledge of the photoprotective mechanism in the photosystem II antenna underlying non-photochemical chlorophyll fluorescence quenching (NPQ). The physiological need for photoprotection of photosystem II and the concept of feed-back control of excess light energy are described. The outline of the major component of nonphotochemical quenching, qE, is suggested to comprise four key elements: trigger (ΔpH), site (antenna), mechanics (antenna dynamics) and quencher(s). The current understanding of the identity and role of these qE components is presented. Existing opinions on the involvement of protons, different LHCII antenna complexes, the PsbS protein and different xanthophylls are reviewed. The evidence for LHCII aggregation and macrostructural reorganization of photosystem II and their role in qE are also discussed. The models describing the qE locus in LHCII complexes, the pigments involved and the evidence for structural dynamics within single monomeric antenna complexes are reviewed. We suggest how PsbS and xanthophylls may exert control over qE by controlling the affinity of LHCII complexes for protons with reference to the concepts of hydrophobicity, allostery and hysteresis. Finally, the physics of the proposed chlorophyll-chlorophyll and chlorophyll-xanthophyll mechanisms of energy quenching is explained and discussed. This article is part of a Special Issue entitled: Photosystem II.     

Antiestrogenic activity of flavonoid phytochemicals mediated via the c-Jun N-terminal protein kinase pathway. Cell-type specific regulation of estrogen receptor alpha

Flavonoid phytochemicals act as both agonists and antagonists of the human estrogen receptors (ERs). While a number of these compounds act by directly binding to the ER, certain phytochemicals, such as the flavonoid compounds chalcone and flavone, elicit antagonistic effects on estrogen signaling independent of direct receptor binding. Here we demonstrate both chalcone and flavone function as cell type-specific selective ER modulators. In MCF-7 breast carcinoma cells chalcone and flavone suppress ERα activity through stimulation of the stress-activated members of the mitogen-activated protein kinase (MAPK) family: c-Jun N-terminal kinase (JNK)1 and JNK2. The use of dominant-negative mutants of JNK1 or JNK2 in stable transfected cells established that the antiestrogenic effects of chalcone and flavone required intact JNK signaling. We further show that constitutive activation of the JNK pathway partially suppresses estrogen (E2)-mediated gene expression in breast, but not endometrial carcinoma cells. Our results demonstrate a role for stress-activated MAPKs in the cell type-specific regulation of ERα function.