Seasonal variations in biomass, growth rate and production rate of the small cyclopoid copepod Oithona davisae in a temperate eutrophic inlet

1998 ◽  
Vol 171 ◽  
pp. 37-44
Author(s):  
S Uye ◽  
K Sano
Keyword(s):  
Growth Rate ◽  
Production Rate ◽  
Seasonal Variations ◽  
Cyclopoid Copepod ◽  
Biomass Growth ◽  
Oithona Davisae

scholarly journals Effect of Different Salinity Levels on Population Dynamics and Growth of the Cyclopoid Copepod Oithona nana

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 190
Author(s):  
Fawzy I. Magouz ◽  
Mohamed A. Essa ◽  
Mustafa Matter ◽  
Abdallah Tageldein Mansour ◽  
Ahmed Gaber ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Transition Period ◽  
Salinity Level ◽  
Food Sources ◽  
Cyclopoid Copepod ◽  
Population Composition ◽  
Optimal Salinity ◽  
Marine Copepod ◽  
Salinity Levels

Copepods are one of the most abundant and diverse live food sources for mesopelagic and bathypelagic fishes and crustaceans. They could contribute to the overlap of the transition period from live feed to an artificial weaning diet in marine larvae production. However, the culture conditions still need optimization to provide sufficient production to cover the increasing demand for marine hatcheries. Therefore, the present study investigated the effects of different salinity levels (5, 10, 15, 20, 25, and 30 ppt) on the population growth, growth rate, and population composition (males, females, copepodite, and nauplii ratio) of the marine copepod, Oithona nana. The experiment continued for 15 days, under laboratory-controlled conditions of temperature (27 ± 1 °C), pH (7.7 ± 0.15), and continuous gentle aeration in 30 L glass aquaria. The copepod culture aquaria were supplemented with a mixture of soybean and yeast (0.5 g 10−6 individual−1 24-h−1) as a feed source. The highest significant population growth and population growth rate of O. nana were achieved with a salinity level of 20 ppt. Regarding population composition, O. nana cultured at the salinity level of 20 ppt recorded the highest significant percentages of copepodite and nauplii. The results concluded that copepod, O. nana, is capable of withstanding abrupt changes in the salinity, but there are limits to their tolerance, with an optimal salinity level of 20 ppt. This salinity level achieved the highest population growth and the highest percentages of copepodite and nauplii of marine Copepoda, O. nana.

Increased glucose utilization and cell growth of Corynebacterium glutamicum by modifying the glucose-specific phosphotransferase system (PTSGlc) genes

2016 ◽  
Vol 62 (12) ◽  
pp. 983-992 ◽  
Author(s):  
Jianzhong Xu ◽  
Junlan Zhang ◽  
Dongdong Liu ◽  
Weiguo Zhang
Keyword(s):  
Growth Rate ◽  
Cell Growth ◽  
Corynebacterium Glutamicum ◽  
Production Rate ◽  
Glucose Consumption ◽  
Chemical Mutagenesis ◽  
Transport Systems ◽  
Phosphotransferase System ◽  
Lysine Production ◽  
Consumption Growth

The phosphoenolpyruvate:glucose phosphotransferase system (PTSGlc) is the major pathway of glucose uptake in Corynebacterium glutamicum. This study investigated glucose consumption rate, cell growth, and metabolite changes resulting from modification of PTSGlc. The classical l-lysine producer C. glutamicum XQ-8 exhibited low glucose consumption, cell growth, and l-lysine production rates, whereas these parameters were significantly increased during cultivating on glucose plus maltose, through inactivation of SugR, or by overexpression of PTSGlc genes. XQ-8sugR::cat/pDXW-8-ptsI exhibited the highest increase in glucose consumption, growth rate, and l-lysine production, followed by XQ-8sugR::cat/pDXW-8-ptsG. However, overexpression of ptsH had little effect on the above-mentioned factors. Although co-overexpression of ptsGHI led to the highest glucose consumption, growth rate, and final l-lysine production; the l-lysine production rate was lower than that of XQ-8sugR::cat/pDXW-8-ptsIH. In fed-batch fermentation, XQ-8sugR::cat/pDXW-8-ptsIH had a higher growth rate of 0.54 h−1 to a dry cell mass of 66 g·L−1 after 16 h, and had a higher l-lysine production rate of 159.2 g·L−1 after 36 h. These results indicate that modification of the sugar transport systems improves amino acid production, especially for mutants obtained by repeated physical and (or) chemical mutagenesis. However, modification of these systems needs to be performed on a case-by-case basis.

scholarly journals Ecophysiological and behavioural responses to salinity and temperature stress in cyclopoid copepod Oithona davisae with comments on gender differences

2020 ◽  
Author(s):  
LEONID SVETLICHNY ◽  
ELENA HUBAREVA ◽  
MARCO UTTIERI
Keyword(s):  
Gender Differences ◽  
Metabolic Rate ◽  
Temperature Response ◽  
Adaptive Strategy ◽  
Cyclopoid Copepod ◽  
Change Rate ◽  
Energy Expenditures ◽  
Oithona Davisae ◽  
Males And Females ◽  
Autumn And Winter

The gender differences in reaction to salinity (3-50) and temperature (6-26°C) stress were studied in the thermophilic cyclopoid copepod Oithona davisae, introduced in the brackish temperate Black Sea since 2001. Both females and males possessed similar salinity tolerance ranges (6–40) irrespective of the salinity change rate, and females displayed a striking osmotic control upon sharp (18-40 and 40-18) salinity shocks. By contrast, the temperature response of males and females were different. Torpidity was recorded at a temperature below 10°C in males collected both in warm and cold seasons, as well as in summer-autumn females whilst in females grown up at the beginning of winter the locomotor parameters were high even at 6°С. The total metabolic rate of summer-autumn and winter females was determined by the level of basal metabolic rate and energy expenditures due to motor activity. In winter females that maintained high activity at low temperature, the total and basal metabolic rates, differing by 2.3 times at all temperatures within the range of 8–28°C, varied in accordance with the temperature coefficient Q10 of about 2, whereas in summer-autumn females at low temperatures total metabolic rate decreased to the basal level. The plasticity of both males and female to wide ranges in abiotic conditions provide an adaptive strategy to sustain the spreading of O. davisae in diverse environments.

scholarly journals Identification of some common food items in the guts of fish larvae and juveniles in the Black Sea

2017 ◽  
Vol 2 (1) ◽  
pp. 3-10 ◽  
Author(s):  
I. V. Vdodovich ◽  
A. N. Khanaychenko ◽  
A. D. Gubanova ◽  
E. A. Kolesnikova ◽  
L. O. Aganesova
Keyword(s):  
Black Sea ◽  
Fish Larvae ◽  
Cyclopoid Copepod ◽  
Annual Number ◽  
The Black Sea ◽  
Stages Of Development ◽  
Zooplankton Community Structure ◽  
Larvae And Juveniles ◽  
Oithona Davisae ◽  
Chitin Fragments

Over the past decade the positive trends in the average annual number of fish larvae and in the copepod population dynamics in the coastal area of the Black Sea agree. The increased fish larvae abundance is hypothesized due to improvement of their nutrition associated with the drastic increase in number of introduced invasive cyclopoid copepod Oithona davisae. This assumption is difficult to be verified through fish gut content analysis in absence of methodology allowing prey species identification from their fragmentary residual remnants. Our paper offers an original approach to identification of several common copepod prey using specific distinctive features detected on their chitin fragments from guts of fish larvae and juveniles. To identify specific features of the common species from the coastal areas off Sevastopol (Acartia tonsa, Oithona davisae, Longipedia sp., Cyclopina sp.), alive copepods were isolated from the samples and reared as monospecific cultures in laboratory. Images of alive copepods of each species at successive stages of development and their moulted exoskeletons were compared with the images of chitin remnants found in the fish guts. This technique discloses relatively intact specific morphological features remaining undigested in chitin fragments of prey. These species-specific taxonomic features are suggested to be used for trophic analysis of the Black Sea fishes at early stages of development. Application of proposed method is helpful for assessment of qualitative and quantitative composition of consumed prey and selectivity of fish, especially during the changes in zooplankton community structure affecting significantly survival of fish generations.

scholarly journals Investigation of a new effective bacterium for cellulosic degradation

2021 ◽  
Author(s):  
Weining Lin
Keyword(s):  
Growth Rate ◽  
Mathematical Models ◽  
Incubation Temperature ◽  
Biogas Production ◽  
Substrate Utilization ◽  
Gas Production ◽  
Biomass Growth ◽  
Growth Substrate ◽  
Wide Range ◽  
Modelling Approach

Clostridium phytofermentans, a newly isolated mesophilic anaerobic bacterium from forest soil, has received considerable attention for its potential application in producing ethanol directly from cellulose. This microorganism produces ethanol, acetate, CO₂ and H₂ as major metabolites from cellulose. Potential applications of this research include the transformation of waste materials into valuable products, such as fuels and organic acids. As an initial part of a multi-staged project, this study is to focus on the characerization of this microorganism growth and to verify the bacterium kinetics, including biomass growth, substrate utilization, and gas production. A series of batch fermentation experiments using cellulose substrate (GS-2C) was performed under the incubation temperature of 37°C. To investigate the effects of pH and substrate concentration (S₀) on growth, 12 trial experiments were conducted with various controlled pH values (7.0 to 8.5) and with various initial cellulose concentration settings (0.1 to 6.0 g/L). Our experimental results showed that the optimal growth condition for C. phytofermentans in batch culture was at pH = 8.4 amd S₀ = 6.0 g/L. Under such condition, the maximum growth rate of 0.37h⁻¹ was observed. Comparing results with other celluloytic clostridium studies, relatively high biomass growth rate using C. phytofermentans is confirmed by our experiments. Mathematical models, using a combination modelling approach with the logistic equation. Monod model, and Luedeking-Piret model, were developed for biomass growth, substrate degradation, and biogas production, respectively, base on our experiment results. This study demonstrated the determination of the four parameters (µmax, Ks, Y, and Smin), which can describe satisfactorily growth or degradation phenomena, using the proposed integration modelling approach. The experiments conducted under wide range conditions, such as changing pH and S₀, not only provide insight into growth kinetics but also provide an opportunity to evaluate the performance of the mathematical models and understand their limitations. This leads to look for improvement or modification to the models. It is foreseen that the findings in this study will enhance the overall understanding of the kinetics of growth and substrate utilization and product formation of this bacterium, and provide important information on the design of the bench-scale anaerobic bioreactor for future studies.

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