פרסומים

The subcellular localization of RNA transcripts provides important insights into biological processes. Hence, understanding the mechanisms underlying RNA targeting is a high priority aim of modern cell biology. The advancements in imaging techniques, such as in situ hybridization and live-cell imaging, coupled with the evolution in optical microscopy led to the discovery that bacterial RNAs, despite the lack of nucleus, are specifically localized. Here we describe the methods used to study RNA localization in bacteria and their applications and discuss their advantages and limitations.

Ice-binding proteins (IBPs) bind to ice crystals and control their structure, enlargement, and melting, thereby helping their host organisms to avoid injuries associated with ice growth. IBPs are useful in applications where ice growth control is necessary, such as cryopreservation, food storage, and anti-icing. The study of an IBP’s mechanism of action is limited by the technological difficulties of in situ observations of molecules at the dynamic interface between ice and water. We describe herein a new, to our knowledge, apparatus designed to generate a controlled temperature gradient in a microfluidic chip, called a microfluidic cold finger (MCF). This device allows growth of a stable ice crystal that can be easily manipulated with or without IBPs in solution. Using the MCF, we show that the fluorescence signal of IBPs conjugated to green fluorescent protein is reduced upon freezing and recovers at melting. This finding strengthens the evidence for irreversible binding of IBPs to their ligand, ice. We also used the MCF to demonstrate the basal-plane affinity of several IBPs, including a recently described IBP from Rhagium inquisitor. Use of the MCF device, along with a temperature-controlled setup, provides a relatively simple and robust technique that can be widely used for further analysis of materials at the ice/water interface.

Milk fat globule (MFG) size and phospholipids (PL) content and composition were determined in milk collected at 65 (pretreatment), 110, 135 and 170 days of lactation from goats randomly assigned to grazing in Mediterranean brushland or fed clover hay indoors, in addition to concentrate. Daily feed intake and dietary contents of neutral detergent fibre and acid detergent fibre were higher in grazing goats, associated with milk richer in fat, with larger MFGs and 20% higher PL content. Smaller MFGs, produced by all confinement groups, was associated with 15 μg g−1 fat higher milk PL content. The greatest effect was found in the Damascus goats, with over 44% higher PL concentration, on milk fat basis, in the confined compared with grazing group. Our understanding of how PL content is modulated by the interaction between genetic background and nutrition will enable to achieve either PL-rich milk or PL-enriched milk fat.

The degradation of malfunctioning or superfluous mitochondria in the lysosome/vacuole is an important housekeeping function in respiring eukaryotic cells. This clearance is thought to occur by a specific form of autophagic degradation called mitophagy, and plays a role in physiological homoeostasis as well as in the progression of late-onset diseases. Although the mechanism of bulk degradation by macroautophagy is relatively well established, the selective autophagic degradation of mitochondria has only recently begun to receive significant attention. In this mini-review, we introduce mitophagy as a form of mitochondrial quality control and proceed to provide specific examples from yeast and mammalian systems. We then discuss the relationship of mitophagy to mitochondrial stress, and provide a broad mechanistic overview of the process with an emphasis on evolutionarily conserved pathways.