scholarly journals Notes on the Cultivation of Two Mixotrophic Dinophysis Species and Their Ciliate Prey Mesodinium rubrum

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 505 ◽  
Author(s):  
Jorge Hernández-Urcera ◽  
Pilar Rial ◽  
María García-Portela ◽  
Patricia Lourés ◽  
Jane Kilcoyne ◽  
...  
Keyword(s):  
Growth Rates ◽  
Exponential Growth ◽  
Mass Production ◽  
Culture Media ◽  
Specific Response ◽  
Region Versus ◽  
Experimental Conditions ◽  
Mesodinium Rubrum ◽  
Dinophysis Acuminata ◽  
Phototrophic Growth

Kleptoplastic mixotrophic species of the genus Dinophysis are cultured by feeding with the ciliate Mesodinium rubrum, itself a kleptoplastic mixotroph, that in turn feeds on cryptophytes of the Teleaulax/Plagioselmis/Geminigera (TPG) clade. Optimal culture media for phototrophic growth of D. acuminata and D. acuta from the Galician Rías (northwest Spain) and culture media and cryptophyte prey for M. rubrum from Huelva (southwest Spain) used to feed Dinophysis, were investigated. Phototrophic growth rates and yields were maximal when D. acuminata and D. acuta were grown in ammonia-containing K(-Si) medium versus f/2(-Si) or L1(-Si) media. Dinophysis acuminata cultures were scaled up to 18 L in a photobioreactor. Large differences in cell toxin quota were observed in the same Dinophysis strains under different experimental conditions. Yields and duration of exponential growth were maximal for M. rubrum from Huelva when fed Teleaulax amphioxeia from the same region, versus T. amphioxeia from the Galician Rías or T. minuta and Plagioselmis prolonga. Limitations for mass cultivation of northern Dinophysis strains with southern M. rubrum were overcome using more favorable (1:20) Dinophysis: Mesodinium ratios. These subtleties highlight the ciliate strain-specific response to prey and its importance to mass production of M. rubrum and Dinophysis cultures.

scholarly journals Prey Lysate Enhances Growth and Toxin Production in an Isolate of Dinophysis acuminata

Toxins ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 57 ◽  
Author(s):  
Han Gao ◽  
Mengmeng Tong ◽  
Xinlong An ◽  
Juliette Smith
Keyword(s):  
Growth Rates ◽  
Management Strategies ◽  
Toxin Production ◽  
Shellfish Poisoning ◽  
Clear Trend ◽  
Live Prey ◽  
Predator Prey ◽  
Whole Cells ◽  
Dinophysis Acuminata ◽  
Phototrophic Growth

The physiological and toxicological characteristics of Dinophysis acuminata have been increasingly studied in an attempt to better understand and predict diarrhetic shellfish poisoning (DSP) events worldwide. Recent work has identified prey quantity, organic nitrogen, and ammonium as likely contributors to increased Dinophysis growth rates and/or toxicity. Further research is now needed to better understand the interplay between these factors, for example, how inorganic and organic compounds interact with prey and a variety of Dinophysis species and/or strains. In this study, the exudate of ciliate prey and cryptophytes were investigated for an ability to support D. acuminata growth and toxin production in the presence and absence of prey, i.e., during mixotrophic and phototrophic growth respectively. A series of culturing experiments demonstrated that the addition of ciliate lysate led to faster dinoflagellate growth rates (0.25 ± 0.002/d) in predator-prey co-incubations than in treatments containing (1) similar levels of prey but without lysate (0.21 ± 0.003/d), (2) ciliate lysate but no live prey (0.12 ± 0.004/d), or (3) monocultures of D. acuminata without ciliate lysate or live prey (0.01 ± 0.007/d). The addition of ciliate lysate to co-incubations also resulted in maximum toxin quotas and extracellular concentrations of okadaic acid (OA, 0.11 ± 0.01 pg/cell; 1.37 ± 0.10 ng/mL) and dinophysistoxin-1 (DTX1, 0.20 ± 0.02 pg/cell; 1.27 ± 0.10 ng/mL), and significantly greater total DSP toxin concentrations (intracellular + extracellular). Pectenotoxin-2 values, intracellular or extracellular, did not show a clear trend across the treatments. The addition of cryptophyte lysate or whole cells, however, did not support dinoflagellate cell division. Together these data demonstrate that while certain growth was observed when only lysate was added, the benefits to Dinophysis were maximized when ciliate lysate was added with the ciliate inoculum (i.e., during mixotrophic growth). Extrapolating to the field, these culturing studies suggest that the presence of ciliate exudate during co-occurring dinoflagellate-ciliate blooms may indirectly and directly exacerbate D. acuminata abundance and toxigenicity. More research is required, however, to understand what direct or indirect mechanisms control the predator-prey dynamic and what component(s) of ciliate lysate are being utilized by the dinoflagellate or other organisms (e.g., ciliate or bacteria) in the culture if predictive capabilities are to be developed and management strategies created.

Morpheme Learning of Children With Specific Language Impairment Under Controlled Instructional Conditions

1992 ◽  
Vol 35 (4) ◽  
pp. 844-852 ◽  
Author(s):  
Phil J. Connell ◽  
C. Addison Stone
Keyword(s):  
Language Impairment ◽  
Specific Language Impairment ◽  
Specific Effect ◽  
Past Research ◽  
Specific Response ◽  
Experimental Conditions ◽  
Phonological Representations ◽  
Specific Language ◽  
Response To Instruction ◽  
Nonverbal Ability

Three groups of children were exposed to instances of a novel morpheme under controlled experimental conditions. The performance of 32 children with specific language impairment (SLI), aged 5:0 to 7:0 years (years:months), was compared to that of 24 normally developing children matched for age and nonverbal ability and 20 younger normally developing children matched for language development and nonverbal ability. The children were taught under two instructional conditions that differed only in whether the child was asked to imitate the new language form after each instance imitation) or just to observe its use (modeling). Consistent with past research (Connell, 1987b), the children with SLI performed significantly better under the imitation condition than under modeling, but the age-matched controls showed no difference in response to instruction. The performance of the language-matched controls was similar to that of the age-matched controls, suggesting that the instruction-specific effect for the children with SLI is not merely a function of general language immaturity. Although the superiority of the imitation condition for the children with SLI was evident for test trials requiring production of the new morpheme (as in past research), no such effect was evident for comprehension trials. This differing effect of output demands suggests that the SLI-specific response to instruction is not a matter of different mastery of the new rule but rather is specific to the need to access the newly induced rule on production trials. The accessing of phonological representations as a possible explanation for the effect is discussed.

scholarly journals Culture media selection for mass production of Isaria fumosorosea and Isaria farinosa

2010 ◽  
Vol 53 (4) ◽  
pp. 753-761 ◽  
Author(s):  
Gabriel Moura Mascarin ◽  
Sérgio Batista Alves ◽  
Rogério Biaggioni Lopes
Keyword(s):  
Mass Production ◽  
Culture Media ◽  
Fungal Species ◽  
Complete Medium ◽  
Sugarcane Molasses ◽  
Liquid Media ◽  
Isaria Fumosorosea ◽  
Isaria Farinosa ◽  
Selection For ◽  
Biphasic Fermentation

This work investigated the production of the fungi Isaria fumosorosea and Isaria farinosa in biphasic fermentation using agro-industrial products and residues. Combinations of natural liquid substrates, alternative to the complete medium and potato dextrose medium, were evaluated. The best liquid media were sugarcane molasses + rice broth, rice broth + yeast and sugarcane molasses + yeast + rice broth, which resulted in the highest viable propagule concentration. The molasses + rice broth medium was selected for the next phase of the study in which the production of both fungal isolates was evaluated in solid grain substrates. In solid-state fermentation, the best conidia production was achieved with the soybean meal and broken corn for I. farinosa, and whole rice and broken rice for I. fumosorosea. Results demonstrated that the two fungal species could be rapidly produced with higher yield of conidia on agro-industrial resources by using biphasic fermentation techniques.

scholarly journals Evaluation of the Biodegradation of Petroleum Contaminants by Pseudomonas Aeruginosa in the Caspian Sea Coastline Waters

2019 ◽  
Vol 13 (3) ◽  
pp. 21-26
Author(s):  
Samira Mehrdad ◽  
◽  
Keivan Saeb ◽  
Lobat Taghavi ◽  
Masood Ghane ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Caspian Sea ◽  
Sea Water ◽  
Culture Media ◽  
Total Petroleum Hydrocarbons ◽  
The Caspian Sea ◽  
Experimental Conditions ◽  
Sustainable Resources ◽  
Life On Earth ◽  
Predominant Strain

Background: Water plays an essential role in supporting life on earth and sea worldwide, requiringclean, safe, high quality and sustainable resources. Nowadays, many water resources have been contaminatedwith toxic compounds originating from petroleumdue to economical and industrial developments. There is anurgent need to clean up the waters with environmentally friendlyand inexpensive methods. This study investigated the biodegradation of total petroleum hydrocarbons (TPH) using Pseudomonas aeruginosa (P. aeruginosa) in southern Caspian Sea coastline. Methods: Coastline sediment samples were collected, with P. aeruginosa being the predominant strain. The bacteria were cultured in triplicates in the presence of 0.5, 1, 2 and 4% of gasoline andunder specific experimental conditions of varying temperature, pH, salinity, shaker speed, and incubation periods. The data representing the gasoline biodegradation in the samples were statistically analyzed. Results: At optimized experimental conditions for temperature, pH, salinity, incubation period, and shaker speed, maximum biodegradation of TPH was achieved by culturing P. aeruginosa strains with the sea water samples containing varying concentrations of gasoline. Conclusion: The gram-negative bacteria, P. aeruginosa, almost completely biodegraded TPH contaminants from the samples’ culture media over 28 days of incubation. We conclude that the use of P. aeruginosa is an efficient method for the biodegradation of Caspian coastal waters contaminated with TPH.

A multitype decomposable age-dependent branching process and its applications

1995 ◽  
Vol 32 (3) ◽  
pp. 591-608 ◽  
Author(s):  
Chinsan Lee ◽  
Grace L. Yang
Keyword(s):  
Tumor Growth ◽  
Life Span ◽  
Growth Rates ◽  
Exponential Growth ◽  
Branching Process ◽  
Asymptotic Formulas ◽  
Stage Model ◽  
Two Stage ◽  
Markov Branching Process ◽  
Age Dependent

Asymptotic formulas for means and variances of a multitype decomposable age-dependent supercritical branching process are derived. This process is a generalization of the Kendall–Neyman–Scott two-stage model for tumor growth. Both means and variances have exponential growth rates as in the case of the Markov branching process. But unlike Markov branching, these asymptotic moments depend on the age of the original individual at the start of the process and the life span distribution of the progenies.

Culture media for mass production of microalgae

2019 ◽  
pp. 33-50 ◽  
Author(s):  
Júlio Cesar de Carvalho ◽  
Eduardo Bittencourt Sydney ◽  
Lorenzo Ferrari Assú Tessari ◽  
Carlos Ricardo Soccol
Keyword(s):  
Mass Production ◽  
Culture Media

scholarly journals A New Approach to Producing High Yields of Pulcherrimin from Metschnikowia Yeasts

Fermentation ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 114
Author(s):  
Ewelina Pawlikowska ◽  
Beata Kolesińska ◽  
Maria Nowacka ◽  
Dorota Kregiel
Keyword(s):  
Culture Media ◽  
Growth Control ◽  
Tween 80 ◽  
Resonance Spectroscopy ◽  
Experimental Conditions ◽  
Biofilm Inhibition ◽  
Iron Chelate ◽  
New Approach ◽  
1H Nuclear Magnetic Resonance ◽  
High Yields

Pulcherrimin, a red iron chelate, is produced by some yeasts and bacteria. It plays important ecological roles in many ecosystems, including growth control, biofilm inhibition and photoprotection. In this study, fifteen yeast strains of the genus Metschnikowia were characterized based on their production of pulcherrimin. Yeast pulcherrimin was isolated and its purity assessed using 1H nuclear magnetic resonance spectroscopy. Under experimental conditions, pulcherrimin formation varied depending on both the tested strains and culture media. The best producers formed up to 240 mg/L of pulcherrimin in minimal medium with glucose as the carbon source, supplemented with 0.05% FeCl3 and 0.1% Tween 80. This study presents a new approach to producing high yields of pulcherrimin from yeasts.

scholarly journals Establishment of a Novel Human Fetal Adrenal Culture Model that Supports de Novo and Manipulated Steroidogenesis

2020 ◽  
Author(s):  
Cecilie Melau ◽  
John E Nielsen ◽  
Signe Perlman ◽  
Lene Lundvall ◽  
Lea Langhoff Thuesen ◽  
...  
Keyword(s):  
De Novo ◽  
Culture Media ◽  
Ex Vivo ◽  
Disorders Of Sex Development ◽  
Endocrine Function ◽  
Specific Response ◽  
Adrenal Tissue ◽  
Sex Development ◽  
Adrenal Steroidogenesis ◽  
Novel Approach

Abstract Context Disorders affecting adrenal steroidogenesis promote an imbalance in the normally tightly controlled secretion of mineralocorticoids, glucocorticoids, and androgens. This may lead to differences/disorders of sex development in the fetus, as seen in virilized girls with congenital adrenal hyperplasia (CAH). Despite the important endocrine function of human fetal adrenals, neither normal nor dysregulated adrenal steroidogenesis is understood in detail. Objective Due to significant differences in adrenal steroidogenesis between human and model species (except higher primates), we aimed to establish a human fetal adrenal model that enables examination of both de novo and manipulated adrenal steroidogenesis. Design and Setting Human adrenal tissue from 54 1st trimester fetuses were cultured ex vivo as intact tissue fragments for 7 or 14 days. Main Outcome Measures Model validation included examination of postculture tissue morphology, viability, apoptosis, and quantification of steroid hormones secreted to the culture media measured by liquid chromatography-tandem mass spectrometry. Results The culture approach maintained cell viability, preserved cell populations of all fetal adrenal zones, and recapitulated de novo adrenal steroidogenesis based on continued secretion of steroidogenic intermediates, glucocorticoids, and androgens. Adrenocorticotropic hormone and ketoconazole treatment of ex vivo cultured human fetal adrenal tissue resulted in the stimulation of steroidogenesis and inhibition of androgen secretion, respectively, demonstrating a treatment-specific response. Conclusions Together, these data indicate that ex vivo culture of human fetal adrenal tissue constitutes a novel approach to investigate local effects of pharmaceutical exposures or emerging therapeutic options targeting imbalanced steroidogenesis in adrenal disorders, including CAH.

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