The endoplasmic reticulum (ER), called "the mother of all membranes," is spotlighted in this timely new book. The work presented here is especially exciting since GFP-technology has provided new ways of looking at the dynamics of the ER and its relationship to other organelles, particularly the Golgi apparatus and peroxisomes. This book provides in-depth knowledge of the ER and the diverse roles it plays, for instance, in protein trafficking, homeostasis of cellular calcium, plant hormone and lipid synthesis. These manifold activities are reflected in the great plasticity of the ER as a structure, with more than a dozen specialized domains recognized for this organelle.

A personal invitation to walk with God through one of the great classics of Christian spirituality. This book of daily devotions is based upon The Cloud of Unknowing. In this edition Robinson sought to remain as true as possible to the voice of this medieval classic. Cloud Devotion follows the original Middle English text sentence by sentence, with Robinson's own translation and paraphrase, divided work into 366 small portions, with a Scripture passage related to the theme from each daily reading. "My heart has yearned for this book. I wanted a guide to help me savor and reflect on the spiritual classic The Cloud of Unknowing. David has insightfully discerned how we might do this. The partnership of this unknown, ancient writer and this known, living pastor is masterful. I invite you into the clouds with the slow reading of this book." -Dr. MaryKate Morse, author and mentor-professor of formation and leadership

Algae have become the favoured object for a whole range of studies in various areas of biology. This first volume in the new series Experimental Phycology comprises 16 contributions presented at the Gottingen algal symposium in September 1989. The articles are centered around several major themes of current interest to algologists and cell biologists. Topics reviewed cover: - "cell walls and " "surfaces" cellulose biosynthesis, scale structures, algal symbionts in ciliates and lichens, cell wall autolysins, marine biofouling, - "reproduction" cell differentiation in "Volvox," the polyspermy block, mitosis in diatoms, nuclear behaviour and cytokinesis in green algae, - "algal evolution" ribosomal RNA sequences, chloroplast evolution, and - "photosynthesis: " phycobilisomes, chlororespiration, thylakoid architecture, electron transfer."

In 1939, when the electron optics laboratory of Siemens & Halske Inc. began to manufacture the first electron microscopes, the biological and medical profes sions had an unexpected instrument at their disposal which exceeded the reso lution of the light microscope by more than a hundredfold. The immediate and broad application of this new tool was complicated by the overwhelming prob lems inherent in specimen preparation for the investigation of cellular struc tures. The microtechniques applied in light microscopy were no longer appli cable, since even the thinnest paraffin layers could not be penetrated by electrons. Many competent biological and medical research workers expressed their anxiety that objects in high vacuum would be modified due to complete dehydration and the absorbed electron energy would eventually cause degrada tion to rudimentary carbon backbones. It also seemed questionable as to whether it would be possible to prepare thin sections of approximately 0. 5 11m from heterogeneous biological specimens. Thus one was suddenly in posses sion of a completely unique instrument which, when compared with the light microscope, allowed a 10-100-fold higher resolution, yet a suitable preparation methodology was lacking. This sceptical attitude towards the application of electron microscopy in bi ology and medicine was supported simultaneously by the general opinion of colloid chemists, who postulated that in the submicroscopic region of living structures no stable building blocks existed which could be revealed with this apparatus."

Als im Jahre 1939 in Berlin im Laboratorium fur Elektronenoptik der Siemens & Halske AG die ersten Elektronenmikroskope serienmassig fabriziert wurden, stan- den den Biologen und Medizinern unerwartet Gerate zur Verfugung, welche das Aufloesungsvermoegen der Lichtmikroskope um das 100fache ubertrafen. Der sofor- tigen und breiten Anwendung dieses neuen Verfahrens in der Erforschung der zel- lularen Strukturen standen aber fast unuberwindliche praparative Schwierigkeiten im Wege. Die bisher in der Lichtmikroskopie verwendete Mikrotechnik konnte nicht ubernommen werden, weil selbst die feinsten Paraffinschnitte von den Elek- tronen nicht durchstrahlt werden konnten. Viele damals kompetente Biologen und Mediziner ausserten auch die Befurchtung, dass die im Hochvakuum befindlichen Objekte durch die vollstandige Entwasserung verandert und schliesslich durch die absorbierte Elektronenenergie bis zu einem rudimentaren Kohlenstoffskelett abge- baut werden wurden. Es schien auch zweifelhaft, ob es gelingen wurde, Dunn- schnitte in der Groessenordnung von 0,5 j. Lm aus den heterogen zusammengesetzten biologischen Praparaten herzustellen. Man besass ploetzlich ein voellig neuartiges In- strument, das gegenuber dem Lichtmikroskop eine um zwei Zehnerpotenzen hoehe- re Aufloesung ermoeglichte, aber keine dafur geeignete Praparationstechnik I Diese skeptische Einstellung zur Anwendung des Elektronenmikroskopes in der Biologie und Medizin wurde gleichzeitig auch durch die Lehrmeinung der damals aktuellen Kolloidchemie unterstutzt, in der postuliert wurde, dass es im amikrosko- pischen Bereich der lebenden Strukturen keine stabilen Bauelemente gebe, die man mit diesem Gerat abbilden koennte. Man stellte sich damals das Cytoplasma, die Kernmatrix, den Inhalt der Mitochondrien und Plastiden als ein amorphes, homo- genes Gelgerust ohne definierte Strukturhierarchie vor.