scholarly journals Enhanced Oxytetracycline Production by Streptomyces rimosus in Submerged Co-Cultures with Streptomyces noursei

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6036
Author(s):  
Tomasz Boruta ◽  
Anna Ścigaczewska

In the present study, Streptomyces rimosus was confronted with Streptomyces noursei, Penicillium rubens, Aspergillus niger, Chaetomium globosum, or Mucor racemosus in two-species submerged co-cultures in shake flasks with the goal of evaluating the oxytetracycline production and morphological development. The co-culture of S. rimosus with S. noursei exhibited stimulation in oxytetracycline biosynthesis compared with the S. rimosus monoculture, whereas the presence of M. racemosus resulted in a delay in antibiotic production. Different strategies of initiating the “S. rimosus + S. noursei” co-cultures were tested. The improvement in terms of oxytetracycline titers was recorded in the cases where S. noursei was co-inoculated with S. rimosus in the form of spores. As the observed morphological changes were not unique to the co-culture involving S. noursei, there was no evidence that the improvement of oxytetracycline levels could be attributed mainly to morphology-related characteristics.

2008 ◽  
Vol 190 (20) ◽  
pp. 6903-6908 ◽  
Author(s):  
Ya-Wen Lu ◽  
Adrianna K. San Roman ◽  
Amy M. Gehring

ABSTRACT The phosphopantetheinyl transferase genes SCO5883 (redU) and SCO6673 were disrupted in Streptomyces coelicolor. The redU mutants did not synthesize undecylprodigiosin, while SCO6673 mutants failed to produce calcium-dependent antibiotic. Neither gene was essential for actinorhodin production or morphological development in S. coelicolor, although their mutation could influence these processes.


2001 ◽  
Vol 64 (5) ◽  
pp. 741-743 ◽  
Author(s):  
DANTE J. BUENO ◽  
JULIO O. SILVA ◽  
GUILLERMO OLIVER

This article reports on the identification of mycoflora of 21 dry pet foods (12 belonging to dogs and 9 to cats) that corresponded to 8 commercial brands made in Argentina and imported. The isolation frequency and relative density of the prevalent fungal genera are compared too. Ten genera and fungi classified as Mycelia sterilia were identified. The predominant genera were Aspergillus (62%), Rhizopus (48%), and Mucor (38%). The most prevalent among Aspergillus was Aspergillus flavus followed by Aspergillus niger and Aspergillus terreus. The predominant Mucor was Mucor racemosus followed by Mucor plumbeus and Mucor globosus. The moisture content of these foods ranged from 5.6 to 10.0% and from 7.2 to 9.9% for dog and cat foods, respectively. A greater moisture content in food for the senior category (9.5 ± 0.2) was observed only in comparison to adult and kitten/puppy. If the moisture content can be maintained at these levels, mold growth would be prevented or at least it would remain at an insignificant level. Some genera and species isolated and identified from the foods analyzed are potentially producing toxins, which are known as mycotoxins. This involves a risk for animal health.


2013 ◽  
Vol 65 (3) ◽  
pp. 955-962 ◽  
Author(s):  
Milica Ljaljevic-Grbic ◽  
M. Stupar ◽  
Jelena Vukojevic ◽  
Ivana Maricic ◽  
Natasa Bungur

Pieces of art stored in museum depots and display rooms are subject to fungal colonization that leads to bio-deterioration processes. Deteriorated wooden sculptures and art photographs temporarily stored in the quarantine room of the Cultural Center of Belgrade were subject to mycological analyses. Twelve fungal species were identified on the wooden substratum and five species were detected on photograph surfaces. Trichoderma viride, Chaetomium globosum and Alternaria sp. were the fungi with proven cellulolytic activity detected on the examined cellulose substrata. Indoor air mycobiota were estimated to 210.09 ? 8.06 CFU m-3, and the conidia of fungus Aspergillus niger were the dominant fungal propagules in the air of the examined room.


Author(s):  
Afaque M. Hossain ◽  
Martin Ehrhardt ◽  
Martin Rudolph ◽  
Dmitry V Kalanov ◽  
Pierre Lorenz ◽  
...  

Abstract Recently, plasma produced by focusing femtosecond laser in gases has been introduced as an etching tool in materials processing. Proper control of the plasma in this application necessitates the apt understanding of the different morphological features of the plasma. In this contribution we show that, the plasma produced in air goes through several stages of morphological development – from ellipsoidal to spherical to toroidal plasma, whereas in argon, axial compression of an ellipsoidal plasma is observed. To explain this dissimilarity, we have quantified the temperature by emission spectroscopy (Planck analysis with Wien’s approximation). The evolution of temperature shows a triple exponential dependence in time which can be correlated with different stages of morphological changes of the plasma. Open Source Field Operation and Manipulation (OpenFOAM) simulations using experimentally determined temperature values show that – (i) the reverse pressure gradient propagates radially inwards and compresses the plasma in both air and argon and forms a localized high pressure zone at the center that generates a secondary pressure wave in air, but not in argon, and (ii) the baroclinic torque that is generated because of the Richtmyer-Meshkov instability, dominates the rate of vorticity in air, whereas effects of flow compressibility and velocity gradients dominate the vortices in argon. Knowledge of the initial state and the dynamics of the subsequent stages of the plasma formation can be utilized for control and optimization of laser-induced plasma applications.


2021 ◽  
Vol 114 ◽  
pp. 43-51
Author(s):  
Marcin Jałoweicki ◽  
Izabela Betlej

Effect of the essential oils addition on the rate of bacterial cellulose surface overgrowth by mold fungi. The aim of this study was to determine the effectiveness of protecting films made of bacterial cellulose with essential oils against overgrowth by mold fungi. The cellulose film produced by microorganisms forming a pellicle called SCOBY was modified by introducing into the cellulose pulp essential oils: cinnamon and manuka. Samples of the protected film were treated with mold fungi: Chaetomium globosum, Aspergillus niger and Trichoderma viride. On the basis of the tests conducted, the rate of film overgrowth by mold fungi and the effectiveness criteria of cellulose film protection with essential oils were determined. The addition of cinnamon oil protected the film against the growth of Aspergillus niger and Chaetomium globosum fungi. Manuka oil slowed down the growth of Chaetomium globosum microorganisms on the surface of the bacterial cellulose film sample, but did not protect the samples from overgrowth. The essential oils tested were ineffective against the fungus Trichoderma viride.


2013 ◽  
Vol 11 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Koshiro Nishikuni ◽  
Guilherme Carvalhal Ribas

Object The surface of the developing fetal brain undergoes significant morphological changes during fetal growth. The purpose of this study was to evaluate the morphological development of the brain sulci from the fetal to the early postnatal period. Methods Two hundred fourteen brain hemispheres from 107 human brain specimens were examined to evaluate the timing of sulcal formation, from its appearance to its complete development. These brains were obtained from cadavers ranging in age from 12 weeks of gestation to 8 months of postnatal life. Results The order of appearance of the cerebral sulci, and the number and percentages of specimens found in this study were as follows: longitudinal cerebral fissure at 12 weeks (10/10, 100%); callosal sulcus at 12 weeks (10/10, 100%); hippocampal sulcus at 15 weeks (7/10, 70%); lateral sulcus at 17 weeks (20/22, 90.9%); circular insular sulcus at 17 weeks (18/22, 81.8%); olfactory sulcus at 17 weeks (18/22, 81.8%); calcarine sulcus at 17 weeks (14/22, 63.6%); parietooccipital sulcus at 17 weeks (11/22, 50%); cingulate sulcus at 19 weeks (16/20, 80%); central sulcus at 21 weeks (22/38, 57.9%); orbital sulcus at 22 weeks (9/16, 56.2%); lunate sulcus at 24 ± 2 weeks (12/16, 75%); collateral sulcus at 24 ± 2 weeks (8/16, 50%); superior frontal sulcus at 25 ± 2 weeks (5/6, 83.3%); rhinal sulcus at 25 ± 2 weeks (3/6, 50%); precentral sulcus at 26 ± 3 weeks (2/4, 50%); postcentral sulcus at 26 ± 3 weeks (2/4, 50%); superior temporal sulcus at 26 ± 3 weeks (2/4, 50%); central insular sulcus at 29 ± 2 weeks (4/4, 100%); intraparietal sulcus at 29 ± 2 weeks (2/4, 50%); paraolfactory sulcus at 29 ± 2 weeks (2/4, 50%); inferior frontal sulcus at 30 ± 3 weeks (2/4, 50%); transverse occipital sulcus at 30 ± 3 weeks (2/4, 50%); occipitotemporal sulcus at 30 ± 3 weeks (2/4, 50%); marginal branch of the cingulate sulcus at 30 ± 3 weeks (2/4, 50%); paracentral sulcus at 30 ± 3 weeks (2/4, 50%); subparietal sulcus at 30 ± 3 weeks (2/4, 50%); inferior temporal sulcus at 31 ± 3 weeks (3/6, 50%); transverse temporal sulcus at 33 ± 3 weeks (6/8, 75%); and secondary sulcus at 38 ± 3 weeks (2/4, 50%). Conclusions The brain is subjected to considerable morphological changes throughout gestation. During fetal brain development the cortex begins to fold in, thereby increasing the cortical surface. All primary sulci are formed during fetal life. The appearance of each sulcus follows a characteristic timing pattern, which may be used as one of the reliable guides pertinent to gestational age and normal fetal development.


1995 ◽  
Vol 8 ◽  
pp. 81-106 ◽  
Author(s):  
David M. Harwood ◽  
Vladimir A. Nikolaev

The Cretaceous record of the diatoms presented here outlines our understanding of their early morphological development. Recent documentation of well preserved Lower Cretaceous (Aptian/Albian) diatom assemblages provides a window into the early history of the diatoms and serves as a base for comparing their subsequent morphological changes. A brief review of diatom biology and morphology is provided to introduce this paper and that of Barron and Baldauf (this volume). Additional background information on the diatoms can be found in the works of Schrader and Schuette (1981), Tappan (1980), Bach and Burkhardt (1984), Barron (1985a, 1993), Fenner (1985), Ricard (1987), Bradbury (1988), Round et al. (1990), and Picket-Heaps et al. (1990).


1984 ◽  
Vol 62 (9) ◽  
pp. 1819-1823 ◽  
Author(s):  
Daniel Cullen ◽  
John H. Andrews

Ascospore suspensions and culture extracts of Chaetomium globosum Kunze: Fr. reduced infection of apple seedlings by Venturia inaequalis (Cke.) Wint. (anamorph, Spilocaea pomi Fr.) in growth-chamber studies. An agar diffusion assay was developed to assess the relative fungistatic activity of culture extracts of C. globosum. No differences were observed in the sensitivity of 37 V. inaequalis strains to C. globosum extracts. Seven strains of C. globosum from diverse habitats were evaluated for antibiotic production in culture. Significant differences in antibiotic production between strains were observed, and antibiotic levels were positively correlated with antagonism to V. inaequalis on seedlings in growth-chamber studies. The antibiotic chetomin was tentatively identified in culture extracts by thin-layer chromatography and ultraviolet absorbance. The selection of high antibiotic producing strains of C. globosum may significantly improve antagonistic performance in the field.


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