Biomineralization and magnetism of bacterial magnetosomes

Magnetosomes of magnetotactic bacteria are of great interest in understanding biomiueralizatiou and possible links between organisms and geomagnetic field. Fossil maguetosomes are ubiquitous in marine and lake sediments and may significantly contribute to magnetic signals. In this review, we firstly introduce some characteristics of magnetotactic bacteria, followed by considering recent progress in maguetosome formation, magnetic measurements, and identification of bacterial magnetites in bulk sediments as well as their paleoenviroumeutal implications. Finally, we briefly discuss potential future breakthroughs in magnetosome studies and its applications.     

From 'beastly philosophy' to medical genetics: eugenics in Russia and the Soviet Union

This essay offers an overview of the three distinct periods in the development of Russian eugenics: Imperial (1900-1917), Bolshevik (1917-1929), and Stalinist (1930-1939). Began during the Imperial era as a particular discourse on the issues of human heredity, diversity, and evolution, in the early years of the Bolshevik rule eugenics was quickly institutionalized as a scientific discipline--complete with societies, research establishments, and periodicals--that aspired an extensive grassroots following, generated lively public debates, and exerted considerable influence on a range of medical, public health, and social policies. In the late 1920s, in the wake of Joseph Stalin's 'Great Break', eugenics came under intense critique as a 'bourgeois' science and its proponents quickly reconstituted their enterprise as 'medical genetics'. Yet, after a brief period of rapid growth during the early 1930s, medical genetics was dismantled as a 'fascist science' towards the end of the decade. Based on published and original research, this essay examines the factors that account for such an unusual--as compared to the development of eugenics in other locales during the same period--historical trajectory of Russian eugenics.     

From ‘Beastly Philosophy’ to Medical Genetics: Eugenics in Russia and the Soviet Union

This essay offers an overview of the three distinct periods in the development of Russian eugenics: Imperial (1900–1917), Bolshevik (1917–1929), and Stalinist (1930–1939). Began during the Imperial era as a particular discourse on the issues of human heredity, diversity, and evolution, in the early years of the Bolshevik rule eugenics was quickly institutionalized as a scientific discipline—complete with societies, research establishments, and periodicals—that aspired an extensive grassroots following, generated lively public debates, and exerted considerable influence on a range of medical, public health, and social policies. In the late 1920s, in the wake of Joseph Stalin's ‘Great Break’, eugenics came under intense critique as a ‘bourgeois’ science and its proponents quickly reconstituted their enterprise as ‘medical genetics’. Yet, after a brief period of rapid growth during the early 1930s, medical genetics was dismantled as a ‘fascist science’ towards the end of the decade. Based on published and original research, this essay examines the factors that account for such an unusual—as compared to the development of eugenics in other locales during the same period—historical trajectory of Russian eugenics.     

Collaborative genome-wide association analysis supports a role for ANK3 and CACNA1C in bipolar disorder

To identify susceptibility loci for bipolar disorder, we tested 1.8 million variants in 4,387 cases and 6,209 controls and identified a region of strong association (rs10994336, P = 9.1 x 10(-9)) in ANK3 (ankyrin G). We also found further support for the previously reported CACNA1C (alpha 1C subunit of the L-type voltage-gated calcium channel; combined P = 7.0 x 10(-8), rs1006737). Our results suggest that ion channelopathies may be involved in the pathogenesis of bipolar disorder.     

Effects of prostaglandin E1 on45Ca++-incorporation and spike activity in longitudinal smooth muscle of cat jejunum

Summary Prostaglandin E₁ (0.3 M) decreased both the⁴⁵Ca⁺⁺-incorporation and the spike activity in isolated longitudinal smooth muscle preparations of the cat jejunum probably by an inhibition on the Ca⁺⁺ influx.     

Seismic evidence for catastrophic slab loss beneath Kamchatka

In the northwest Pacific Ocean, a sharp corner in the boundary between the Pacific plate and the North American plate joins a subduction zone running along the southern half of the Kamchatka peninsula with a region of transcurrent motion along the western Aleutian arc. Here we present images of the seismic structure beneath the Aleutian-Kamchatka junction and the surrounding region, indicating that: the subducting Pacific lithosphere terminates at the Aleutian-Kamchatka junction; no relict slab underlies the extinct northern Kamchatka volcanic arc; and the upper mantle beneath northern Kamchatka has unusually slow shear wavespeeds. From the tectonic and volcanic evolution of Kamchatka over the past 10 Myr (refs 3-5) we infer that at least two episodes of catastrophic slab loss have occurred. About 5 to 10 Myr ago, catastrophic slab loss shut down island-arc volcanic activity north of the Aleutian-Kamchatka junction. A later episode of slab loss, since about 2 Myr ago, seems to be related to the activity of the world's most productive island-arc volcano, Klyuchevskoy. Removal of lithospheric mantle is commonly discussed in the context of a continental collision, but our findings imply that episodes of slab detachment and loss are also important agents in the evolution of oceanic convergent margins.     

The evolution of alternative parasitic life histories in large blue butterflies

Large blue (Maculinea) butterflies are highly endangered throughout the Palaearctic region, and have been the focus of intense conservation research. In addition, their extraordinary parasitic lifestyles make them ideal for studies of life history evolution. Early instars consume flower buds of specific host plants, but later instars live in ant nests where they either devour the brood (predators), or are fed mouth-to-mouth by the adult ants (cuckoos). Here we present the phylogeny for the group, which shows that it is a monophyletic clade nested within Phengaris, a rare Oriental genus whose species have similar life histories. Cuckoo species are likely to have evolved from predatory ancestors. As early as five million years ago, two Maculinea clades diverged, leading to the different parasitic strategies seen in the genus today. Contrary to current belief, the two recognized cuckoo species show little genetic divergence and are probably a single ecologically differentiated species. On the other hand, some of the predatory morphospecies exhibit considerable genetic divergence and may contain cryptic species. These findings have important implications for conservation and reintroduction efforts.     

A synthetic homing endonuclease-based gene drive system in the human malaria mosquito

Genetic methods of manipulating or eradicating disease vector populations have long been discussed as an attractive alternative to existing control measures because of their potential advantages in terms of effectiveness and species specificity. The development of genetically engineered malaria-resistant mosquitoes has shown, as a proof of principle, the possibility of targeting the mosquito's ability to serve as a disease vector. The translation of these achievements into control measures requires an effective technology to spread a genetic modification from laboratory mosquitoes to field populations. We have suggested previously that homing endonuclease genes (HEGs), a class of simple selfish genetic elements, could be exploited for this purpose. Here we demonstrate that a synthetic genetic element, consisting of mosquito regulatory regions and the homing endonuclease gene I-SceI, can substantially increase its transmission to the progeny in transgenic mosquitoes of the human malaria vector Anopheles gambiae. We show that the I-SceI element is able to invade receptive mosquito cage populations rapidly, validating mathematical models for the transmission dynamics of HEGs. Molecular analyses confirm that expression of I-SceI in the male germline induces high rates of site-specific chromosomal cleavage and gene conversion, which results in the gain of the I-SceI gene, and underlies the observed genetic drive. These findings demonstrate a new mechanism by which genetic control measures can be implemented. Our results also show in principle how sequence-specific genetic drive elements like HEGs could be used to take the step from the genetic engineering of individuals to the genetic engineering of populations.