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[en] Highlights: • Yeast cells were used as carriers for hosting metal nanoparticles via in situ metal ion reduction. • Yeast cells carrying metal nanoparticles are “green” hierarchical particle systems without any chemical stabilizers or dispersants. • Ag nanoparticles with size of about 4 nm were produced inside yeast cells by UV illumination. • Ag nanoparticles with size of about 9 nm were produced in the cell envelope by chemical reduction. • Pd nanoparticles with size of about 11 nm were almost evenly distributed in every parts of yeast cells.
[en] A total of 117 acid producing baceria were isolated from grass and silage samples. Almost all isolates, 115 isolates posses homfermentative fermentation. All isolates produced lactic acid in a range of 0.36-2.05%. From their growth and their ability in producing lactic acid, two isolates, a coccus (T3-2-02) and a rod (T3-0-01) were selected for a mixed wild type strains for silage inoculant. After irradiation the wild type strains with gama ray, 51 and 58 isolates of high acid producer were selected from T3-2-02 and T3-0-01 strains, respectively. After testing the growht characteristics and the acid productivity, a coccus strain, MC08 and a rod stain, MR4 were choosen as a mixed irradiated starter culture strains for grass silage fermentation using a 50 dats old Pangola grass (Digitaria eriantha). The experiment was divided into 6 treatments. Treatmet I was the control. Treatmment 2, 4% molasses was added ro the grass. Treatment 3, a mixed wild type strains (T3-2-02+ T3-0-01) was inoculated into the grass. Treatment 4, a mixed irradiated strains (MC08+ MR04) was used. Treatment 5, A mixed wild tpye strains was used and supplemented with 4% molasses. Treatnebt 6, A mixed irradiated strain was assed and supplemented with 4% molasses. The results showed that a qualified silage can be obtained within a week from either the treatment inoculated with starter culture together with4% molasses (T5 and T6) or the treatment supplemented with 4% molasses alone (T2). further more, Silage of the treatments that using starter culture supplemented with 4% molasses gave volatile acid in a requred quantity. Silage of the treatments that inoculated either with a wild type pr a mixed irradiated starter culture posses bether quality than the control treatment. Further more silage that used irradiated starter culture showed a faster ffermentation and higher lactic acid production tha silage that uses wild type starter culture.
[en] Study was made on samples of seed culture and fermented wort from Gyogon alcohol distillery. In all samples bacteria contaminants were observed. Samples were cultured on Sabouraud dextrose agar, Czapek Dox agar, and nutrient agar media and broth. The selected colonies were isolated. Biochemical tests for identification were conducted. The yeast and bacteria contaminants were identified by morphological characteristics and biochemical reactions. The yeast isolated and identified from Gyogon alcohol distillery was Sacchacromyces cerevisiae. The bacteria contaminants isolated and identified were Aeromonas sp. and Pseudomonas sp.
[en] The tolerance to ionizing radiation stress is present among different classes and species of organisms. As listed by Rainey et al., ionizing radiation resistant organisms were isolated from a variety of different sources like processed/canned food items, paper industry, soil and water samples. Apart from extensively reported bacteria and Archea group, many fungal species like Aspergillus, Curvularia, Alternaria, Cryptococcus, and Ustilago maydis have been found to be resistant to ionizing radiation. However, different environmental sources are constantly been explored for novel radioresistant organisms, which can help in understanding the molecular mechanism behind these extreme stress responses. On the basis of this, present study was initiated to find novel radiation resistant yeast from sea water source
[en] The species of yeasts included in the studies are Saccharomyces cerevisiae, Rhodeterula rubra, Rhodeterula pilimane and those isolated from fruits such as citrus, papaya and banana. Part of the project involved induction of sporulation to obtain haploid cells for crossing to produce stable disploids exhibiting improved protein production. Although S. cerevisiae produce less protein than Rhodeterula, it produces ascesperes which are haploid cells. These haploid cells can be used to obtain stable diploids with the desirable characteristics by crossing cultures. Rhodeterula, a fungus that does not produce ascesperes will be subjected to certain adverse conditions to induce, hopefully, sperulation
[en] Complete text of publication follows. In vivo molecular-level information is essentially important for understanding the structure, dynamics and functions of living cells. We use Raman microspectroscopy to single living budding yeast cells under a starving condition and study the dynamic behaviour of the 'Raman spectroscopic signature of life' (Y. Naito et al., J. Raman. Spectrosc., 36 (2005) 837-839. and Y-S. Huang et al., Biochemistry, 44 (2005) 10009-10019.) in relation to the formation and disappearance of a 'dancing body' in a vacuole. A focus is placed on the cell death process and the recovery from it. Our previous studies have shown that, under a starving condition, a dancing body appears suddenly in a vacuole and that the 'Raman spectroscopic signature of life' disappears concomitantly indicating the loss of the mitochondrial metabolic activity. This event is followed by gradual deterioration of the cell structure leading to death. This cell death process was visualized at the molecular level by time-resolved Raman imaging. In the present study, we show strong correlations not only between the appearance of a dancing body and the loss of the mitochondrial activity but also between the disappearance of the dancing body and the recovery of the activity. Time- and space-resolved Raman spectra of a single living budding yeast cell were recorded on a confocal Raman microspectrometer with 632.8 nm line of a He-Ne laser for excitation. The laser power at the sample was about 5 mW. The lateral and depth resolutions were about 300 nm with a 100 x oil immersion objective lens (N.A.=1.3) and about 2 μm with a 100 μm pinhole for a confocal detection. Raman spectra were recorded in the wavenumber range 300 - 1800 cm-1 with a spectral resolution of 3 cm-1. The exposure time was 150 sec. Saccharomyces cerevisiae/ Saccharomyces Bayanus hybrid, strain AJL3062 from, was grown at 30 deg C under a stationary cultivation condition in wort medium. The cells dispersed in 1 ml of wort culture medium were placed and immobilized on a ConA-coated glass-bottom dish. In order to provide nutrients to starving yeast cells, 2 ml of fresh wort medium was added to the sample solution. The exposure time was 150 sec. The present study has made it clear that the addition of fresh wort medium after the appearance of a dancing body (and the concomitant disappearance of the 'Raman spectroscopic signature of life') can avoid cell death. Time- and space-resolved Raman spectroscopic studies have provided a clue for elucidating what happens between the life and death at the cellular level.
[en] A novel configuration of dual-channel line optical tweezers with a ‘Y’ shape is constructed for sorting of particles within a microfluidic chip. When yeast cells with different size pass the intersection of the specially designed line optical tweezers, they are separated and transported to different channels due to a difference in the forces exerted by the line tweezers that depends on the size of the cells. The influences of some experimental conditions, such as laser power and flow velocity, on the sorting efficiency are discussed. (paper)