Structural aspects of osmoregulation in porphyra

1978 ◽  
Vol 36 (2) ◽  
pp. 412-413
Author(s):  
C. Wiencke ◽  
A. Lauchli
Keyword(s):  
Culture Medium ◽  
Point Of View ◽  
Chemical Fixation ◽  
Cellular Organization ◽  
Osmotic Adaptation ◽  
Osmotic Balance ◽  
Activity Of Enzymes ◽  
Osmotic Agents ◽  
Vacuolar System ◽  
Structural Aspects

Osmoregulatory mechanisms in algae were investigated mainly from a physiological point of view (KAUSS 1977, HELLEBUST 1976). In Porphyra two osmotic agents, i. e. floridoside/isofloridoside (KAUSS 1968) and certain ions, such as K+ and Na+(EPPLEY et al. 1960) are considered for osmotic balance. Accumulations of ions (particularly Na+) in the cytoplasm during osmotic adaptation is improbable, because the activity of enzymes is generally inhibited by high ionic concentrations (FLOWERS et al. 1977).The cellular organization of Porphyra was studied with special emphasis on the development of the vacuolar system under different hyperosmotic conditions. Porphyra was cultivated at various strengths of the culture medium ASP 12 (PROVASOLI 1961) ranging from normal to 6 times concentrated (6x) culture medium. Por electron microscopy freeze fracturing was used (specimens fixed in 2% glutaraldehyde and incubated in 30% glycerol, preparation in a BALZERS BA 360 M apparatus), because chemical fixation gave poor results.

Appropriating others' words: Traces of literature and peer culture in a third-grader's writing

1994 ◽  
Vol 23 (3) ◽  
pp. 411-426 ◽  
Author(s):  
Timothy J. Lensmire ◽  
Diane E. Beals
Keyword(s):  
Social Context ◽  
Mikhail Bakhtin ◽  
Point Of View ◽  
Future Research ◽  
Peer Culture ◽  
Development Discourse ◽  
Children's Writing ◽  
Developmental Point ◽  
Structural Aspects

ABSTRACTMikhail Bakhtin's notion of appropriation is a potentially powerful way to conceptualize discourse development in children. Typically, studies of discourse development have emphasized structural aspects of text. However, children appropriate not only forms, but also words, themes, purposes, and styles. From a developmental point of view, the concept of appropriation raises at least three questions: What is it that children appropriate? Where do they get their material? And what do they do with that material? In an attempt to make sense of appropriation as a developmental construct, we examine one third-grader's writing: Suzanne's book, The missing piece. We find that Suzanne appropriated material from two major sources: (a) adult-authored text – Margaret Sidney's novel, Five little Peppers and how they grew – and (b) the meanings and values of a stratified local peer culture. We conclude by discussing the significance of this work for future research on children's discourse development. (Discourse development, Mikhail Bakhtin, peer culture, social context of writing, children's writing, appropriation)

scholarly journals Chemical Characterization of Atlantic Cod (Gadus morhua) Collagen Hydrolyzed Using Enzyme Preparation Derived from Red King Crab (Paralithodes camtschaticus) and Its Potential as a Core Component of Bacterial Culture Medium

2021 ◽  
Author(s):  
Vitaliy Yu. Novikov ◽  
Nadezhda V. Shumskaya ◽  
Vyacheslav A. Mukhin ◽  
Konstantin V. Zolotarev ◽  
Anton N. Mikhailov ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Culture Medium ◽  
Bacterial Culture ◽  
Atlantic Cod ◽  
Red King Crab ◽  
Paralithodes Camtschaticus ◽  
King Crab ◽  
Enzyme Preparations ◽  
Murmansk Region ◽  
Activity Of Enzymes

The Atlantic cod (Gadus morhua) and red king crab (Paralithodes camtschaticus) processing wastes are massive and unutilized in the Murmansk region of Russia. The samples of skin-containing waste of Atlantic cod fillets production were hydrolyzed using enzyme preparations derived from red king crab hepatopancreases, porcine pancreases and Bacillus subtilis bacteria. The activity of enzymes from crab hepatopancreases was significantly higher than the activity of enzymes derived from other sources. The optimal conditions of the hydrolysis process have been figured out. The samples of cod processing waste hydrolysate were analyzed for amino acid composition and molecular weight distribution. The samples of hydrolysate were used as core components for bacterial culture medium samples. The efficiency of the medium samples was tested for Escherichia coli growth rate; the most efficient sample had efficiency 95.3% of that of a commercially available medium based on fish meal. Substitution of medium components with those derived from industrial by-products is one of the ways to decrease a cost of a culture medium in biopharmaceutical drug production.

A plunge-freezing method for imaging mammalian tissue culture cells

1991 ◽  
Vol 49 ◽  
pp. 58-59
Author(s):  
E.T. O'Toole ◽  
J.R. McIntosh
Keyword(s):  
Tissue Culture ◽  
Culture Medium ◽  
Freeze Substitution ◽  
Chemical Fixation ◽  
Freezing Method ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Humidity Chamber ◽  
Cellular Components ◽  
Coated Carbon

Ultrarapid freezing of tissue culture cells followed by freeze substitution has been used a method for the optimum fixation of cytoskeletal components that are often sensitive to routine chemical fixation. This is due to the fact that freezing methods such as plunge freezing, result in the almost instantaneous fixation of all cellular components without alteration of the cell's morphology. In addition, we have found that the plunge freezing method is useful for obtaining thin frozen cells for direct cryoimaging. Here we describe how the plunge freezing method can be applied both for freeze substitution analysis and for direct cryoimaging of frozen tissue culture cells.PTK, cells were grown to confluence on formvar coated, carbon stabilized gold grids. Prior to freezing, the grids were blotted in a 37°C, high humidity chamber so that a minimum of culture medium remained on the grid. This blotting step was critical to obtain a sample thin enough for optimum cryopreservation and subsequent cryoimaging.

BM_Virtual Enterprise

2011 ◽  
pp. 124-144 ◽  
Author(s):  
Goran D Putnik ◽  
Maria M. Cunha ◽  
Rui Sousa ◽  
Paulo Avila
Keyword(s):  
Formal Specification ◽  
Basic Concept ◽  
Enterprise Architecture ◽  
Reference Model ◽  
Virtual Enterprise ◽  
Point Of View ◽  
Dynamically Reconfigurable ◽  
Definition Of ◽  
Structural Aspects

BM_virtual enterprise (BM_VE) is a virtual enterprise (VE) in a total or partial conformance with the BM_virtual enterprise architecture reference model (BM_VEARM). BM_VE is a kind of VE characterized as a dynamically reconfigurable network integrated over the global domain, satisfying the requirements for integrability, distributivity, agility, and virtuality as competitiveness factors. BM_VE uses three main mechanisms, or tools: market of resources, broker, and virtuality. This chapter presents the three fundamental mechanisms for the VE reconfiguration dynamics and virtuality; introduces the basic concept of the BM_VEARM, which serves as the conceptual and formal base for building BM_VE instances; shows the formal specification and theory of the structural aspects of the BM_VE as well as some aspects of the BM_VE reconfiguration dynamics; presents the BM_VE as an agile/virtual enterprise (A/VE); and finally, describes some important consequences of virtuality in BM_VE, i.e., that the BM_VE structure is hierarchical, a new definition of the VE (in which the network as the VE characteristic is irrelevant from the operational unit’s point of view), and the process of a “traditional” enterprise virtualization.

scholarly journals Identification of the Initial Steps in d-Lysine Catabolism in Pseudomonas putida

2007 ◽  
Vol 189 (7) ◽  
pp. 2787-2792 ◽  
Author(s):  
Olga Revelles ◽  
Rolf-Michael Wittich ◽  
Juan L. Ramos
Keyword(s):  
Pseudomonas Putida ◽  
Nitrogen Source ◽  
Culture Medium ◽  
Point Of View ◽  
Open Reading Frames ◽  
Gene Encoding ◽  
Carbon And Nitrogen ◽  
Extension Analysis ◽  
Reading Frames ◽  
Lysine Catabolism

ABSTRACT Pseudomonas putida uses l-lysine as the sole carbon and nitrogen source which preferentially requires its metabolism through two parallel pathways. In one of the pathways δ-aminovalerate is the key metabolite, whereas in the other l-lysine is racemized to d-lysine, and l-pipecolate and α-aminoadipate are the key metabolites. All the genes and enzymes involved in the d-lysine pathway, except for those involved in the conversion of d-lysine into Δ1-piperideine-2-carboxylate, have been identified previously (30). In this study we report that the conversion of d-lysine into Δ1-piperideine-2-carboxylate can be mediated by a d-lysine aminotransferase (PP3590) and a d-lysine dehydrogenase (PP3596). From a physiological point of view PP3596 plays a major role in the catabolism of d-lysine since its inactivation leads to a marked reduction in the growth rate with l- or d-lysine as the sole carbon and nitrogen source, whereas inactivation of PP3590 leads only to slowed growth. The gene encoding PP3590, called here amaC, forms an operon with dpkA, the gene encoding the enzyme involved in conversion of Δ1-piperideine-2-carboxylate to l-pipecolate in the d-lysine catabolic pathway. The gene encoding PP3596, called here amaD, is the fifth gene in an operon made up of seven open reading frames (ORFs) encoding PP3592 through PP3597. The dpkA amaC operon was transcribed divergently from the operon ORF3592 to ORF3597. Both promoters were mapped by primer extension analysis, which showed that the divergent −35 hexamers of these operon promoters were adjacent to each other. Transcription of both operons was induced in response to l- or d-lysine in the culture medium.

scholarly journals Aquaporins: A Multidisciplinary Perspective on The Water Channel Proteins

Acta Medica ◽  
2020 ◽  
Vol 51 (2) ◽  
pp. 30-42
Author(s):  
Gokce Alp ◽  
Iffet Ipek Bosgelmez ◽  
Yesim Oztas
Keyword(s):  
Cell Proliferation ◽  
Cell Migration ◽  
Water Channel ◽  
High Water ◽  
Point Of View ◽  
Biomimetic Membranes ◽  
Channel Proteins ◽  
Recent Developments ◽  
Osmotic Balance ◽  
Multidisciplinary Perspective

Aquaporins are unique water channel proteins located at cell membranes that possess high water permeability and high solute rejection. Their primary function is to maintain the osmotic balance of the cells via regulating the water transport. However, their discovery had also provided the scientists to understand the pathophysiology of some diseases. In fact, aquaporins are shown to be strongly related to cancer by taking part in several tumor-related processes such as cell migration, cell proliferation and cell adhesion. Other than their functions in human body, recently, aquaporins have started to be used in engineering biomimetic membranes, for different applications such as desalination. This review investigates the properties and functions of the aquaporins in a multidisciplinary point of view and demonstrates the recent developments in aquaporin-based research.

scholarly journals The membrane proteins of the vacuolar system. II. Bidirectional flow between secondary lysosomes and plasma membrane.

1980 ◽  
Vol 86 (1) ◽  
pp. 304-314 ◽  
Author(s):  
W A Muller ◽  
R M Steinman ◽  
Z A Cohn
Keyword(s):  
Plasma Membrane ◽  
Culture Medium ◽  
Fluid Phase ◽  
Membrane Flow ◽  
Em Autoradiography ◽  
Secondary Lysosomes ◽  
Bidirectional Flow ◽  
Vacuolar System ◽  
Representative Samples ◽  
Pinocytic Vesicles

Lactoperoxidase covalently coupled to latex spheres (LPO-latex) has been used to selectively iodinate the phagolysome (PL) membrane within living macrophages, as discussed in the accompanying article. This procedure labeled approximately 24 polypeptides in the PL membrane; these were similar to those iodinatable on the external surface of the plasma membrane (PM). We now report on the translocation and fate of these proteins when the cells are returned to culture. TCA-precipitable radioactivity was lost from cells with biphasic kinetics. 20-50% of the cell-associated radiolabel was rapidly digested (t 1/2 approximately equal to 1 h) and recovered in the culture medium as monoiodotyrosine. 50-80% of the label was lost slowly from cells ( 1/2 approximately equal to 24-30 h). Quantitative analysis of gel autoradiograms showed that all radiolabeled proteins were lost at the same rate in both the rapid and slow phases of digestion. Within 15-30 min aftr labeling of the PL membrane, EM autoradiography revealed that the majority of the cell-associated grains, which at time 0 were associated with PL, were now randomly dispersed over the plasmalemma. At this time, analysis of PM captured by a second phagocytic load revealed the presence of all labeled species originally present in the PL membrane. This demonstrated the rapid, synchronous centrifugal flow of PL polypeptides to the cell surface. Evidence was also obtained for the continuous influx of representative samples of the PM into the PL compartment by way of pinocytic vesicles. This was based on the constant flow of fluid phase markers into latex-containing PL and on the internalization of all iodinatable PM polypeptides into this locus. These observations provide evidence for the continuous, bidirectional flow of membrane polypeptides between the PM and the secondary lysosome and represent an example of a membrane flow and recycling mechanism.

scholarly journals Chemical Characterization of Atlantic Cod (Gadusmorhua) Collagen Hydrolyzed Using Enzyme Preparation Derived from Red King Crab (Paralithodes Camtschaticus) and Its Potential as a Core Component of Bacterial Culture Medium

Marine Drugs ◽  
2021 ◽  
Vol 19 (8) ◽  
pp. 472
Author(s):  
Vitaliy Yu. Novikov ◽  
Nadezhda V. Shumskaya ◽  
Vyacheslav A. Mukhin ◽  
Konstantin V. Zolotarev ◽  
Anton N. Mikhailov ◽  
...  
Keyword(s):  
Culture Medium ◽  
Bacterial Culture ◽  
Atlantic Cod ◽  
Chemical Characterization ◽  
Red King Crab ◽  
King Crab ◽  
Enzyme Preparations ◽  
Medium Components ◽  
Murmansk Region ◽  
Activity Of Enzymes

The Atlantic cod (Gadusmorhua) and red king crab (Paralithodescamtschaticus) processing wastes are massive and unutilized in the Murmansk region of Russia. The samples of skin-containing waste of Atlantic cod fillets production were hydrolyzed using enzyme preparations derived from red king crab hepatopancreases, porcine pancreases, and Bacillus subtilis bacteria. The activity of enzymes from crab hepatopancreases was significantly higher than the activity of enzymes derived from other sources. The optimal conditions of the hydrolysis process have been figured out. The samples of cod processing waste hydrolysate were analyzed for amino acid composition and molecular weight distribution. The samples of hydrolysate were used as core components for bacterial culture medium samples. The efficiency of the medium samples was tested for Escherichia coli growth rate; the most efficient sample had an efficiency of 95.3% of that of a commercially available medium based on fish meal. Substitution of medium components with those derived from industrial by-products is one of the ways to decrease a cost of a culture medium in biopharmaceutical drug production.

scholarly journals In vitro conservation of Piper aduncum and Piper hispidinervum under slow-growth conditions

2011 ◽  
Vol 46 (4) ◽  
pp. 384-389 ◽  
Author(s):  
Tatiane Loureiro da Silva ◽  
Jonny Everson Scherwinski-Pereira
Keyword(s):  
Low Temperatures ◽  
Culture Medium ◽  
Shoot Growth ◽  
Slow Growth ◽  
Growth Conditions ◽  
In Vitro Cultures ◽  
In Vitro Conservation ◽  
Piper Aduncum ◽  
Osmotic Agents

The objective of this work was to evaluate in vitro storage of Piper aduncum and P. hispidinervum under slow-growth conditions. Shoots were stored at low temperatures (10, 20 and 25°C), and the culture medium was supplemented with osmotic agents (sucrose and mannitol - at 1, 2 and 3%) and abiscisic acid - ABA (0, 0.5, 1.0, 2.0 and 3.0 mg L-1). After six-months of storage, shoots were evaluated for survival and regrowth. Low temperature at 20ºC was effective for the in vitro conservation of P. aduncum and P. hispidinervum shoots. In vitro cultures maintained at 20ºC on MS medium showed 100% survival with slow-growth shoots. The presence of mannitol or ABA, in the culture medium, negatively affected shoot growth, which is evidenced by the low rate of recovered shoots.

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