Get help from the best in academic writing.

Yeast Activity in Rice Wine Fermentation

In this study, the effect of different starter culture has been studied and the activity of yeast during the rice wine fermentation also being observed. The UHT milk were being mix with different kind of starter culture. Later, the yoghurt mixture were being incubated and further undergoes chilling period which results in the desired yogurt. Natural yogurt and Lactobacillus Casei Shirota had been chosen to be the best among other starter culture as the pH is drop dramatically and this proves that, the metabolite activity was high. As for rice wine fermentation, yeast was being added into the rice and being mix thoroughly. The specific gravity and pH were being observed. The pH value of the rice wine decreasing as this proves that the acidity is increasing due to the metabolite activity of yeast. The specific gravity of the yeast shows increase as this indicates that the sugar were being extracted out from the rice.
Introduction Ethanol fermentation had been found by human beings which indicates that the change that being caused by the bacterial action could results in the formation of products that were enjoyable to consume. For example, the spoilage of fruit juices can results in the formation of wine.
An early experiment carried out by Eduard Buchner in 1896 in which he grounded up a group of cell with sand until it totally being destroyed. The liquid that remain were being extracted and being added to sugar solution. He assume that fermentation could not occur since the cells are dead because there are no “life-force” needed to carry out fermentation (Albasi et al., 2001).
Fermentation is the process which produces alcoholic beverages or acidic products. The fermentation which occur basically involves in the breaking down of complex organic substances into simple substances (Budslawski and Drabent, 1972). Glycolysis provide an energy towards the microorganism and causing sugar molecules to be split up and the electrons were removes from electrons to molecules (Arici et al, 2004). The electrons were being passed around to an organic molecule such as pyruvic acid resulting in the formation of a waste product such as lactic acid, ethyl alcohol and etc which is vital to utilized fermentation (Arici et al, 2004).
The production of yogurt is mainly through fermentation by lactic acid bacteria at the range of 27⁰C – 40⁰C. The mechanism by which the synergistic effect of Streptococcus spp. and Lactobacillus spp. have been well studied (Collins and Gibson, 1999). The process mainly involves in the pretreatment of milk, homogenization, heat treatment and cooling. Many study have been done towards the probiotic bacteria which can be used as the starter culture in the yogurt production which being health benefits (Shortt, 1999).
In the rice wine production, the end product which is wine is resulted from glucose fermentation. Glucose which is present in the rice will be broken down to form alcohol under favourable condition of the yeast (Arici et al., 2004). The rice wine will continue until all sugar were used up and being converted to alcohol. Based on (Arici et al, 2004), the process of producing rice wine has two steps where by saccharification process is the first step which uses fungal in order to hydrolyse the rice starch into sugar.
The next step which involves are utilizing the product of saccharification to ethanol which can be describe as below:
In this experiment, the studies aim to look the effect of different starter culture that has being used for yogurt production and to observe the rice wine fermentation in the changing of pH and specific gravity.

Stem Cells: History, Properties and Research

History Stem cells are cells found in all multi cellular organisms. They are characterized by the ability to renew themselves through mitotic cell division and differentiate into a diverse range of specialized cell types. Research in the stem cell field grew out of findings by Ernest A. McCulloch and James E. Till at the University of Toronto in the 1960s
The two broad types of mammalian stem cells are: embryonic stem cells that are isolated from the inner cell mass of blastocysts, and adult stem cells that are found in adult tissues. In a developing embryo, stem cells can differentiate into all of the specialized embryonic tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing specialized cells, but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues.
Stem cells can now be grown and transformed into specialized cells with characteristics consistent with cells of various tissues such as muscles or nerves through cell culture. Highly plastic adult stem cells from a variety of sources, including umbilical cord blood and bone marrow, are routinely used in medical therapies. Embryonic cell lines and autologous embryonic stem cells generated through therapeutic cloning have also been proposed as promising candidates for future therapies
Contents (Jump to)
1 Properties
1.1 Self-renewal
1.2 Potency definitions
1.3 Identification
2 Embryonic
3 Adult
4 Amniotic
5 Induced pluripotent
6 Lineage
7 Treatments
8 Research patents
9 Key research events
10 References
Properties The classical definition of a stem cell requires that it possess two properties:
Self-renewal – the ability to go through numerous cycles of cell division while maintaining the undifferentiated state.
Potency – the capacity to differentiate into specialized cell types. In the strictest sense, this requires stem cells to be either totipotent or pluripotent – to be able to give rise to any mature cell type, although multipotent or unipotent progenitor cells are sometimes referred to as stem cells.
Two mechanisms exist to ensure that the stem cell population is maintained:
Obligatory asymmetric replication – a stem cell divides into one daughter cell that is identical to the original stem cell, and another daughter cell that is differentiated
Stochastic differentiation – when one stem cell develops into two differentiated daughter cells, another stem cell undergoes mitosis and produces two stem cells identical to the original.
Potency definitions
Pluripotent, embryonic stem cells originate as inner mass cells within a blastocyst. The stem cells can become any tissue in the body, excluding a placenta. Only the morula’s cells are totipotent, able to become all tissues and a placenta.
Human embryonic stem cells
A: Cell colonies that are not yet differentiated.
B: Nerve cell
Potency specifies the differentiation potential (the potential to differentiate into different cell types) of the stem cell.
Totipotent (a.k.a omnipotent) stem cells can differentiate into embryonic and extraembryonic cell types. Such cells can construct a complete, viable, organism. These cells are produced from the fusion of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg are also totipotent.
Pluripotent stem cells are the descendants of totipotent cells and can differentiate into nearly all cells, i.e. cells derived from any of the three germ layers.
Multipotent stem cells can differentiate into a number of cells, but only those of a closely related family of cells.
Oligopotent stem cells can differentiate into only a few cells, such as lymphoid or myeloid stem cells.
Unipotent cells can produce only one cell type, their own, but have the property of self-renewal which distinguishes them from non-stem cells (e.g. muscle stem cells).
The practical definition of a stem cell is the functional definition – a cell that has the potential to regenerate tissue over a lifetime. For example, the gold standard test for a bone marrow or hematopoietic stem cell (HSC) is the ability to transplant one cell and save an individual without HSCs. In this case, a stem cell must be able to produce new blood cells and immune cells over a long term, demonstrating potency. It should also be possible to isolate stem cells from the transplanted individual, which can themselves be transplanted into another individual without HSCs, demonstrating that the stem cell was able to self-renew.
Properties of stem cells can be illustrated in vitro, using methods such as clonogenic assays, where single cells are characterized by their ability to differentiate and self-renew. As well, stem cells can be isolated based on a distinctive set of cell surface markers. However, in vitro culture conditions can alter the behavior of cells, making it unclear whether the cells will behave in a similar manner in vivo. Considerable debate exists whether some proposed adult cell populations are truly stem cells.
Embryonic Embryonic stem cell lines (ES cell lines) are cultures of cells derived from the epiblast tissue of the inner cell mass (ICM) of a blastocyst or earliermorula stage embryos. A blastocyst is an early stage embryo-approximately four to five days old in humans and consisting of 50-150 cells. ES cells are pluripotent and give rise during development to all derivatives of the three primary germ layers: ectoderm, endoderm and mesoderm. In other words, they can develop into each of the more than 200 cell types of the adult body when given sufficient and necessary stimulation for a specific cell type. They do not contribute to the extra-embryonic membranes or the placenta.
Nearly all research to date has taken place using mouse embryonic stem cells (mES) or human embryonic stem cells (hES). Both have the essential stem cell characteristics, yet they require very different environments in order to maintain an undifferentiated state. Mouse ES cells are grown on a layer of gelatin and require the presence of Leukemia Inhibitory Factor (LIF). Human ES cells are grown on a feeder layer of mouse embryonic fibroblasts(MEFs) and require the presence of basic Fibroblast Growth Factor (bFGF or FGF-2). Without optimal culture conditions or genetic manipulation, embryonic stem cells will rapidly differentiate.
A human embryonic stem cell is also defined by the presence of several transcription factors and cell surface proteins. The transcription factors Oct-4,Nanog, and Sox2 form the core regulatory network that ensures the suppression of genes that lead to differentiation and the maintenance of pluripotency. The cell surface antigens most commonly used to identify hES cells are the glycolipids SSEA3 and SSEA4 and the keratan sulfate antigens Tra-1-60 and Tra-1-81. The molecular definition of a stem cell includes many more proteins and continues to be a topic of research.
After nearly ten years of research, there are no approved treatments using embryonic stem cells. The first human trial was approved by the US Food