Centromere regulation: new players, new rules, new questions

Centromeres support the assembly of the kinetochore on every chromosome and are therefore essential for the proper segregation of sister chromatids during cell division. Centromere identity is regulated epigenetically through the presence of the histone H3 variant CENP-A. CENP-A regulation and incorporation specifically into centromeric nucleosomes are the matter of intensive studies in many different model organisms. Here we briefly review the current knowledge in centromere biology with a focus on Drosophila melanogaster and how these insights lead to new rules and challenges.     

互惠共生微生物：新资源，新技术，新机遇，新挑战

2020年9月联合国环境规划署发布《全球生物多样性展望-5》(GBO-5)报告,助力世界实现协商一致的愿景——到2050年“与自然和谐相处”。其实,原本地球上的所有生物都是相互依存、互惠共生于地球村的,尽管存在少数“坏分子”。但由于人类的贪婪,过度扩张才导致地球“千疮百孔”的面貌,严重威胁到人类文明可持续发展。通过最近20年的研究,互惠共生微生物(mutualistic symbiotic microbes,MSM)从其丰富的群落多样性到种质新资源、从多种多样的生理生态功能到作用机制、从基础探究到新技术研发,为实现人与自然和谐相处的愿景提供了新机遇,同时也面临新挑战。令人可喜的是,中国在MSM研究领域取得了令世人瞩目的成果。《微生物学通报》于2020年11期特别推出了“互惠共生微生物专栏”,旨在展现中国MSM研究的最新进展和成果,促进生物共生学的发展壮大。     

A new family,new genus,and new species allied to the Microsporida

A new and unusual microsporidian species was found in the intestinal epithelium of dipteran larvae of genus Sciara. Merogony is by binary and multiple fission. Sporogonial plasmodia become enclosed in ornate, thick-walled cysts. The cyst contents become cut up by temporary cytoplasmic partitions to make numerous binucleate cells (sporonts) Each divides to produce one normal and one abortive sporoblast. Because this species has a number of unusual features, a new family and a new genus are proposed to contain it.     

Holoprosencephaly: new models, new insights

Holoprosencephaly (HPE) is a common congenital malformation that is characterised by a failure to divide the forebrain into left and right hemispheres and is usually accompanied by defects in patterning of the midline of the face. HPE exists in inherited, autosomal dominant (familial) forms and mutation-associated sporadic forms, but environmental factors are also implicated. There are several features of HPE that are not well understood, including the extremely variable clinical presentation, even among obligate carriers of familial mutations, and the restriction of structural anomalies to the ventral anterior midline, despite association with defects in signal transduction pathways that regulate development of many additional body structures. The new animal models described in this review may help unravel these puzzles. Furthermore, these model systems suggest that human HPE arises from a complex interaction between the timing and strength of developmental signalling pathways, genetic variation and exposure to environmental agents.     

Oral vaccines: new needs, new possibilities

Vaccination is an important tool for handling healthcare programs both in developed and developing countries. The current global scenario calls for a more-efficacious, acceptable, cost-effective and reliable method of immunization for many fatal diseases. It is hoped that the adoption of oral vaccines will help to provide an effective vaccination strategy, especially in developing countries. Mucosal immunity generated by oral vaccines can serve as a strong first line of defense against most of the pathogens infecting through the mucosal lining. Advances in elucidating the mechanism of action of oral vaccines will facilitate the design of more effective, new generation vaccines. There are promising developments in the use of different agents to effectively deliver the vaccine candidate. It is hoped that ongoing research may be able to set another cardinal point, after polio vaccine, in eradicating infectious diseases.     

A new species,new combinations,and a new name in Acanthaceae from northern South America

A new species of Acanthaceae (Ruellia saülensis) is described and illustrated from French Guiana, and three new combinations (Justicia potarensis, J. flaviflora, andJ. tobagensis) and one new name (Justicia coppenamensis) are proposed. The new species is compared to its closest relative (Ruellia rubra), and a justification of the transfers is provided.