Morphology of immature bovine oocytes

Bovine cumulus oocyte complexes (COCs) as used for in vitro maturation and fertilization can be classified into different categories by light microscopical inspection. We have distinguished four categories based on compactness and transparency of the cumulus investment and homogeneity and transparency of the ooplasm. The four categories were studied for their morphological characteristics at the ultrastructural level and for their developing capacity in an in vitro maturation system. In categories 1 and 2 oocytes, organelles were evenly distributed. In categories 3 and 4, oocytes organelles were clustered and the distribution of the organelles mimicked the characteristics of oocytes during final maturation. Cumulus cell process endings penetrated the cortex of the oocyte or were located superficial to the cortex of the oocyte. In category 1 oocytes, most of the process endings penetrated the cortex. In category 4 oocytes, most of the process endings did not penetrate. In categories 2 and 3 oocytes, both forms of process endings did occur. After in vitro maturation, only category 4 oocytes showed a decreased developing capacity. Categories 1–3 oocytes showed equal developing capacity in an in vitro maturation system.     

Localisation of the glucose-fructose oxidoreductase in wild type and overproducing strains of Zymomonas mobilis

Abstract The enzyme glucose-fructose oxidoreductase (GFOR) from the Gram-negative ethanologenic bacterium Zymomonas mobilis was purified to homogeneity and was shown to be a tetrameric protein with a subunit size of M _r 42 500. Using immunogold-labelling in combination with electron microscopy, ultrathin sections of Z. mobilis wild type cells showed that the enzyme GFOR is located in the periplasm off the bacterial cells. Z. mobilis strains which carried the cloned gfo gene on plasmid pSUP104, had 5–6-fold increased GFOR enzyme activities. Moreover, these cells accumulated large amounts of a presumable unprocessed pre-GFOR protein ( M _r 48 000).     

Diurnal sleep depth changes in the king penguin (<Emphasis Type="Italic">Aptenodytes patagonicus</Emphasis>)

Avian sleep quality depends on its depth (deeper sleep being of better quality). In king penguins (Aptenodytes patagonica), sleep may be disturbed by congeners passing in the sleeper's vicinity. As king penguin activity is increased in the morning, sleep disturbances are more likely to occur during this time period. One might therefore assume that afternoon sleepers (AS) sleep more profoundly than morning sleepers (MS). To test this hypothesis, we examined the diurnal variations in sleep depth of king penguins sleeping in resting sites adjacent to the colony of 'La Baie du Marin' (Crozet Archipelago). We measured the bodily tactile arousal threshold at the upper back level. The arousal threshold in AS was twice as high as in MS. This study demonstrates for the first time that sleep depth changes according to time of day in a diurnal wild bird. We postulate that diurnal sleep depth is increased due to decreased congener movements close to the sleeping penguin.     

On the relevance of precision autophagy flux control in vivo – Points of departure for clinical translation

ABSTRACT

Macroautophagy (which we will call autophagy hereafter) is a critical intracellular bulk degradation system that is active at basal rates in eukaryotic cells. This process is embedded in the homeostasis of nutrient availability and cellular metabolic demands, degrading primarily long-lived proteins and specific organelles.. Autophagy is perturbed in many pathologies, and its manipulation to enhance or inhibit this pathway therapeutically has received considerable attention. Although better probes are being developed for a more precise readout of autophagic activity in vitro and increasingly in vivo, many questions remain. These center in particular around the accurate measurement of autophagic flux and its translation from the in vitro to the in vivo environment as well as its clinical application. In this review, we highlight key aspects that appear to contribute to stumbling blocks on the road toward clinical translation and discuss points of departure for reaching some of the desired goals. We discuss techniques that are well aligned with achieving desirable spatiotemporal resolution to gather data on autophagic flux in a multi-scale fashion, to better apply the existing tools that are based on single-cell analysis and to use them in the living organism. We assess how current techniques may be used for the establishment of autophagic flux standards or reference points and consider strategies for a conceptual approach on titrating autophagy inducers based on their effect on autophagic flux . Finally, we discuss potential solutions for inherent controls for autophagy analysis, so as to better discern systemic and tissue-specific autophagic flux in future clinical applications.

Abbreviations: GFP: Green fluorescent protein; J: Flux; MAP1LC3/LC3: Microtubule-associated protein 1 light chain 3; n_A: Number of autophagosomes; TEM: Transmission electron microscopy; τ: Transition time