THE EFFECT OF AMMONIUM SULPHATE (ZA) FERTILIZER CONCENTRATION ON THE GROWTH OF MICROALGA POPULATION (Nannochloropsis oculata)

This research was conducted from 24 June to 6 July 2019 in the Regional Technical Implementation Unit of the Seawater and Brackish Aquaculture Fisheries Center (UPTD BPBALP Teluk Buo), West Sumatra. This study aim to determine the effect of Ammonium Sulfate ((NH4)2SO4) with different concentrations on the growth rate of Nannochloropsis oculata microalgae population. The method used in this study is an experimental method using a completely randomized design (CRD) one factor, namely ZA fertilizer concentration. There were 5 (five) levels concentration tested, namely 0 ml/L (control treatment), 30 ml/L (treatment A), 40 ml/L (treatment B), 50 ml/L (treatment C), and 60 ml/L (treatment D) total of 15 treatment units. The test organism in this study was N. oculata. The container used is a glass jar (2 liter capacity). The test parameters in this study are the maximum cell population density achieved during 5 days of maintenance (120 hours), relative growth, self-doubling time and specific growth rate during the exponential growth phase. The results of this study indicate that the best concentration of ZA fertilizer for cell population growth is 40 ml/L, followed by a concentration of 30 ml/L, a concentration of 50 ml/L, a concentration of 60 ml/L and the lowest at a concentration of 0 ml/L (control) .

Lie Symmetry Analysis and Invariant Solutions of a Nonlinear Fokker-Planck Equation Describing Cell Population Growth

In this paper, a complete Lie symmetry analysis is performed for a nonlinear Fokker-Planck equation for growing cell populations. Moreover, an optimal system of one-dimensional subalgebras is constructed and used to find similarity reductions and invariant solutions. A new power series solution is constructed via the reduced equation, and its convergence is proved.

Cell population growth regulates dorsalization and caudalization during chick morphogenesis and programmed cell death in lens fibres

The chick embryo ectoblast was examined for a possible relationship between the state of neural competence and cell population growth. It was found that although ectoblast cells with doubling times ranging between 5 to 20 h exhibit neural competence, the extent of neutralization induced by the Hensen’s node depends on the duration of the cell cycle; the longer the doubling time of the competent ectoblast, the stronger the induction and the greater the induced neural tissue. Neural induction in the competent ectoblast occurs in at least two steps: the first lasts for 1-2 h of direct contact with the inducing Hensen’s node graft; a contact for another 2 h with even a non-inducing post-nodal fragment is essential to consolidate neutralization. Hensen’s node graft induces mitotic activity in the competent ectoblast in contact. Teratogens which inhibit cell population growth, development and blastoderm expansion in chick embryo gastrula cause concomitant caudalization of the embryonic axis. We confirm Yamada’s hypothesis that dorsalization is under positive mitogenic control, whereas caudalization is controlled by a negative cell cycle regulation. Reverse transcripts of chick gastrula mRNA were cloned in pBR322. Colony hybridization with cDNA made against chicken yolk RNA showed positive clones. Thus chicken yolk contains maternal mRNAs. cDNA made against mRNA extracted from stage 10 foreheads was hybridized with RNA from stage 1 to 13 embryos, 19 day lens and egg yolk. The hybridization signal, which was low between stages 1 to 7, increased between stages 10-13 and decreased thereafter. Forehead cDNA also hybridized to yolk RNA. Thus, maternal RNA sequences are present in the early chick embryo. During lens development, epithelial cells retain proliferative activity and their progeny reaching a stationary phase join the fibre area and contribute to the growth of fibre cells. The rate of transfer from epithelium to fibre regulates the rate of programmed cell death of the non-dividing differentiated lens fibre cells.

Intraspecific plasticity in circadian rhythms within Euglena gracilis strain Z

Natural plasticity in overt circadian rhythms can be observed in various animals. Little is known about how this phenomenon help Euglena gracilis adapt to environmental stimuli. We used four groups of strain Z. Two groups were from our laboratory, ZObihiro1 and ZObihiro2; Third group was from the National Institute for Environmental Studies, Japan (ZNIES-48) and the other was from Osaka Prefecture University (ZOsaka). The latter two were grown photoautotrophically at a light intensity of 84 μmol m-2 s-1 (day-white type lamps) at 25°C with air bubbling, as were ours, for two months prior to experiments. Results showed that ZObihiro2 and ZOsaka grew faster than ZObihiro1 and ZNIES-48. Upon transferring from light to darkness, population growth ceased within 8-10 h with the cell number increase in the dark of 41% in ZObihiro1 and ZObihiro2, 35% in ZOsaka and remarkably low 22% in ZNIES-48. Timing of cell division bursts in the circadian rhythm of cell population growth in 24 h light-dark cycles was the same in all four groups. Magnitudes of the rhythm were different: both ZObihiro1 and ZObihiro2 completely doubled, but ZNIES-48 multiplied by 1.9, and ZOsaka multiplied feebly by 1.7. The photoinduction of commitment to cell division in DD followed a circadian rhythm. All four showed the same peak at subjective dusk, but the amplitudes differed in the order, ZObihiro2 > ZOsaka > ZObihiro1 >> ZNIES-48. The resistance to photosensitization against Rose-Bengal follows a clear circadian rhythm in all substrains except in ZNIES-48. ZObihiro1 and ZOsaka showed the phasing similar to UV resistance rhythm, but ZObihiro2 did not. These results suggest the plasticity of circadian rhythms within a species, if not within a strain. Moreover, it is also apparent that different substrains/ecotypes present within the same Z strain. Int. J. Appl. Sci. Biotechnol. Vol 7(2): 207-216

clonealign: statistical integration of independent single-cell RNA & DNA-seq from human cancers

Measuring gene expression of genomically defined tumour clones at single cell resolution would associate functional consequences to somatic alterations, as a prelude to elucidating pathways driving cell population growth, resistance and relapse. In the absence of scalable methods to simultaneously assay DNA and RNA from the same single cell, independent sampling of cell populations for parallel measurement of single cell DNA and single cell RNA must be computationally mapped for genome-transcriptome association. Here we presentclonealign, a robust statistical framework to assign gene expression states to cancer clones using single-cell RNA-seq and DNA-seq independently sampled from an heterogeneous cancer cell population. We applyclonealignto triple-negative breast cancer patient derived xenografts and high-grade serous ovarian cancer cell lines and discover clone-specific dysregulated biological pathways not visible using either DNA-Seq or RNA-Seq alone.

Stochastic Models for Population Dynamics

Cell growth and division are stochastic processes that exhibit significant amount of cell-to-cell variation and randomness. In order to connect single cell division dynamics with overall cell population, stochastic population models are needed. We summarize the basic concepts, computational approaches and discuss simple applications of this modeling approach to understanding cancer cell population growth as well as population fluctuations in experiments.

Toxicology across scales: Cell population growth in vitro predicts reduced fish growth

Environmental risk assessment of chemicals is essential but often relies on ethically controversial and expensive methods. We show that tests using cell cultures, combined with modeling of toxicological effects, can replace tests with juvenile fish. Hundreds of thousands of fish at this developmental stage are annually used to assess the influence of chemicals on growth. Juveniles are more sensitive than adult fish, and their growth can affect their chances to survive and reproduce. Thus, to reduce the number of fish used for such tests, we propose a method that can quantitatively predict chemical impact on fish growth based on in vitro data. Our model predicts reduced fish growth in two fish species in excellent agreement with measured in vivo data of two pesticides. This promising step toward alternatives to fish toxicity testing is simple, inexpensive, and fast and only requires in vitro data for model calibration.