Wh-P and the Intervention Effect of negation

Following the Government and Binding theory mainly developed by Chomsky (1981, 1982, 1986), I explore wh-P and the Intervention Effect of negation in Late Archaic Chinese (LAC). I propose that the inverted order of wh-P in LAC is generated via PP inversion followed by the separate preposing of wh and P. The wh-complement raises to [Spec, PP] and further moves to the specifier position of a functional projection. If the wh-PP is base-generated preverbally, the preposition moves to the head position of the functional projection directly; if the wh-PP is base-generated postverbally, the preposition must first incorporate to a V0 and then move to the head position of the functional projection through excorporation. In terms of the Intervention Effect, wh-arguments and adverbials that usually move to the Low focus position below negation are subject to a blocking effect caused by negation, so these wh-phrases have to land in the High focus position above negation which is expected to accommodate ‘high’ adverbials exclusively. I argue that the Intervention Effect in LAC is a consequence of Q-binding as feature movement of [wh], interacting with fronting into the hierarchy of clause-internal positions driven by [Focus] feature.

Inverted meiosis: an alternative way of chromosome segregation for reproduction

Canonical meiosis is characterized by two sequential rounds of nuclear divisions following one round of DNA replication—reductional segregation of homologous chromosomes during the first division and equational segregation of sister chromatids during the second division. Meiosis in an inverted order of two nuclear divisions—inverted meiosis has been observed in several species with holocentromeres as an adaptive strategy to overcome the obstacle in executing a canonical meiosis due to the holocentric chromosome structure. Recent findings of co-existence of inverted and canonical meiosis in two monocentric organisms, human and fission yeast, suggested that inverted meiosis could be common and also lead to the puzzle regarding the mechanistic feasibility for executing two meiosis programs simultaneously. Here, we discuss apparent conflicts for concurrent canonical meiosis and inverted meiosis. Furthermore, we attempt to provide a working model that may be compatible for both forms of meiosis.

Examination of pinanediol–boronic acid ester formation in aqueous media: relevance to the relative stability of trigonal and tetrahedral boronate esters

The “inverted” order of stabilities Ktrig > Ktet is observed for pinanediol boronate esters in spite of the existence of the usual strain release effect in the O–B–O angle of the cyclic diol ester.

Centromere repositioning causes inversion of meiosis and generates a reproductive barrier

The chromosomal position of each centromere is determined epigenetically and is highly stable, whereas incremental cases have supported the occurrence of centromere repositioning on an evolutionary time scale (evolutionary new centromeres, ENCs), which is thought to be important in speciation. The mechanisms underlying the high stability of centromeres and its functional significance largely remain an enigma. Here, in the fission yeast Schizosaccharomyces pombe, we identify a feedback mechanism: The kinetochore, whose assembly is guided by the centromere, in turn, enforces centromere stability. Upon going through meiosis, specific inner kinetochore mutations induce centromere repositioning—inactivation of the original centromere and formation of a new centromere elsewhere—in 1 of the 3 chromosomes at random. Repositioned centromeres reside asymmetrically in the pericentromeric regions and cells carrying them are competent in mitosis and homozygotic meiosis. However, when cells carrying a repositioned centromere are crossed with those carrying the original centromere, the progeny suffer severe lethality due to defects in meiotic chromosome segregation. Thus, repositioned centromeres constitute a reproductive barrier that could initiate genetic divergence between 2 populations with mismatched centromeres, documenting a functional role of ENCs in speciation. Surprisingly, homozygotic repositioned centromeres tend to undergo meiosis in an inverted order—that is, sister chromatids segregate first, and homologous chromosomes separate second—whereas the original centromeres on other chromosomes in the same cell undergo meiosis in the canonical order, revealing hidden flexibility in the perceived rigid process of meiosis.

Transformation of 1,2-Dithiole-3-thiones Into 1,6,6aλ4-Trithiapentalenes via Reaction with Bromoethanones

We report the reactions of derivatives of 5-amino-3-thioxo-3H-1,2-dithiole-4-carboxylic acid 1 with bromoethanones and acylation agents. Two different routes were used to obtain the products, 3-(acylmethylidene)-3H-1,2-dithioles 4. These compounds were synthesized by acylation of compounds 1 on the amino group, followed by the reaction with bromoethanones and excess of triethylamine. Another method was based on the inverted order of the mentioned reaction steps and in absence of a base. The treatment of 4 with thionyl chloride gave new unsaturated fused lactones 13 whereas thionation led to desired 1,6,6aλ4-trithiapentalenes 5. The structures of products and the reaction mechanisms are discussed.