Engineering the bilayer: Emerging genetic tool kits for mechanistic lipid biology

The structural diversity of lipids underpins the biophysical properties of cellular membranes, which vary across all scales of biological organization. Because lipid composition results from complex metabolic and transport pathways, its experimental control has been a major goal of mechanistic membrane biology. Here, we argue that in the wake of synthetic biology, similar metabolic engineering strategies can be applied to control the composition, physicochemical properties, and function of cell membranes. In one emerging area, titratable expression platforms allow for specific and genome-wide alterations in lipid biosynthetic genes, providing analog control over lipidome stoichiometry in membranes. Simultaneously, heterologous expression of biosynthetic genes and pathways has allowed for gain-of-function experiments with diverse lipids in non-native systems. Finally, we highlight future directions for tool development, including recently discovered lipid transport pathways to intracellular lipid pools. Further tool development providing synthetic control of membrane properties can allow biologists to untangle membrane lipid structure-associated functions.     

Plant bioregenerative life supports: The Italian CAB Project

Abstract

The Bioregenerative Life Support program CAB (Controllo Ambientale Biorigenerativo) is a key element of the Italian Space Agency (ASI) Medicine & Biotechnology scientific program, set forth in the ASI Activity Plan 2006–2008. The CAB program started in October 2006, under the prime partnership of Thales Alenia Space Italia, with a feasibility study of a controlled biological system, allowing the regeneration of resources and the production of food for life support in long duration missions. Main constituents of the CAB program are: (a) Higher plants as basic elements for food and oxygen production, CO₂ regeneration and water purification via the photosynthetic and leaf transpiration processes, and (b) biological & physico-chemical systems for environmental control, monitoring, power & data distribution, etc. The sectors of technological and scientific concern are practically all the ones typical for life support systems in the frame of long duration human missions; i.e., food production, in particular via the cultivation of higher plants, and food management; air regeneration (production of O₂, removal of CO₂, trace gas control); water regeneration (urine processing, gray water processing, potable water management); solid waste processing; resources allocation and storage; control of environmental conditions (Thermal-hygrometric, light, pressure, radiation, etc).     

Meeting report: Second international meeting on quadruplex DNA

A two and a half day meeting on G-quadruplexes was held in Louisville, KY, USA (April 18–21, 2009). A specific goal of this conference was to promote discussion on the biology of G-quadruplexes. In practice this was represented in four main ways, namely in biophysics, bio/nanotechnology, therapeutics, and what might be termed “intrinsic biology”. Research into the basic biophysical and structural properties of G-quadruplexes continues to be important for understanding biology, and for optimizing aptamers for therapeutic and bio/technological purposes. The meeting comprised two Keynote lectures, twenty-three invited talks, and forty-two posters covering various aspects of these topics using a wide variety of technologies.     

The Role of Intuitive Ontologies in Scientific Understanding – the Case of Human Evolution

Psychological evidence suggests that laypeople understand the world around them in terms of intuitive ontologies which describe broad categories of objects in the world, such as ‘person’, ‘artefact’ and ‘animal’. However, because intuitive ontologies are the result of natural selection, they only need to be adaptive; this does not guarantee that the knowledge they provide is a genuine reflection of causal mechanisms in the world. As a result, science has parted ways with intuitive ontologies. Nevertheless, since the brain is evolved to understand objects in the world according to these categories, we can expect that they continue to play a role in scientific understanding. Taking the case of human evolution, we explore relationships between intuitive ontological and scientific understanding. We show that intuitive ontologies not only shape intuitions on human evolution, but also guide the direction and topics of interest in its research programmes. Elucidating the relationships between intuitive ontologies and science may help us gain a clearer insight into scientific understanding.     

Biological flora of central Europe: Solidago gigantea Aiton

Solidago gigantea is a rhizomatous perennial herb native to northern America and introduced in Europe. It is a serious invader of disturbed mesic sites, often forming dense monospecific stands. We review the literature on taxonomy, morphology, population biology, cytology, physiology, chemistry, and ecology of this species.     

Anatomical Studies of Citrus jambhiri Lush. Roots Infected by Pratylenchus coffeae

All motile stages of Pratylenchus coffeae infected mature and immature tissues of Citrus jambhiri (rough lemon) seedling tap roots. The nematodes fed primarily in the cortex and colonized in pockets or cavities. Intra- and intercellular migration within the cortex occurred in either direction from the point of entry. When P. coffeae invaded a root tip the meristem often was destroyed and lateral root initiation usually occurred near the destroyed root tip. Males were essential for reproduction and survived at least 2 1/2 months within root tissues, but with males alone used as inoculum, no cortical pockets were formed. On infected trees in the field P. coffeae were most numerous in C. jambhiri feeder roots.     

Suppression of Embryogenesis and Hatching in Meloidogyne javanica by Thermal Stress

Embryogenes is and hatching of eggs of Meloidogyne javanica were suppressed by brief heat treatment (46 C for 10 min). The period of suppression or arrested development differs according to the stage of development of the nematode when heat treatment is applied. The effect on hatching is much more pronounced than on embryogenesis.     

Take two people—a genetics teaching kit

This easily made kit has proved very effective in teaching genetics to pupils of low ability     

Polygenic inheritance of bean mass

Analogies between plants and animals are often a source of confusion in the understanding of sexual reproduction in green plants

The ancient view that plants are non-sexual because they hold a place below animals on the ladder of nature was still held by many scientists in the 1 8th century. Paradoxically, al this time, Linnaeus and others were also postulating the universality of plant sexuality by using analogies with animals to over-extend the slowly emerging experimental evidence about the functions of floral parts. Today's school leavers seem to have similarly diverse views. A lack of school focus on gamete fusion appears to result in a continuing reliance on analogies with animals, and a belief that plants undergo only a qualified version of sexual reproduction. Suggestions for classroom activities to overcome this are offered, and some wider implications are considered.