Archaeological excavations carried out in the ancient settlement of Sumhuram (3rd century BC–5th century AD) in the area of Khor Rori (Dhofar Governorate, southern Oman), brought to light pottery ...showing a pink-violet substance. In order to reveal the nature of this pink-violet colour, the substance was chemically examined by laser desorption-ionization mass spectrometry (LDI-MS) and high performance liquid chromatography-diode array detection (HPLC-DAD). The analytical investigations provided a detailed molecular composition of the organic fraction of the pink-violet material, highlighting the presence of 6,6′-dibromoindigo, 6-monobromoindigo, 6,6′-dibromoindirubin, 6- and 6′-monobromoindirubin, indigo and indirubin. The results revealed that shellfish purple was the source. In addition, in some of the pottery fragments, alizarin and purpurin, which are the molecular markers of madder type dyestuffs, were also ascertained by LDI-MS. The analytical results enabled us to draw hypotheses not only on the possible function of such vessels as dye baths, but also that, since Sumhuram was one of the most important harbours in southern Arabia during the pre-Islamic time, it was also possibly a centre for the production and trade of purple pigments.
A psychrotrophic XT1 strain (CGMCC 1194) isolated from a glacier in China's Xinjiang province produced violet pigments at a high content. This strain was identified as
Janthinobacterium lividum XT1 ...by API kit and 16S rDNA analysis. The main fraction of violet pigment was violacein based on the analysis by HPLC-MS and
1H NMR. The pigment production by
J. lividum XT1 was not associated with the cell growth, and a cultivation temperature lower than 20
°C was required for the cell growth and pigment production. Sucrose was the most suitable carbon source, and casein was the best nitrogen source for cell growth and pigment formation. Mineral components in the medium, including CaNO
3, FeSO
4, riboflavin, MgSO
4 and nicotinic acid, showed different effects on the cell growth and pigment production. The maximum pigment productivity reached 0.8
g pigment per dry cell weight. The pigment production pattern by our isolate was different from that by other strains such as
J. lividum reported so far.
The aims of this work were to identify and characterize for some important technological properties the yeast species present throughout the ripening process of Pecorino Crotonese, a traditional ...cheese produced in a well defined area of Southern Italy. In particular, the strain technological properties considered include fermentation/assimilation of galactose and lactose, assimilation of lactate and citrate in the presence of different NaCl concentrations, hydrolysis of butter fat, skim milk, gelatine and casein, production of brown pigments in cheese agar and ability to produce biogenic amines. High yeast levels were recorded in cheese samples already after 5
h of brining (about 5
log
cfu/g) and these concentration remained constant during ripening. The yeast isolates belonged to restrict number of yeast species. While
Kluyveromyces lactis and
Saccharomyces cerevisiae were isolated prevalently in the first stages of Pecorino Crotonese production,
Yarrowia lipolytica and
Debaryomyces hansenii dominated during the later stages of maturation. Otherwise, the latter two were very NaCl resistant species. In fact,
D. hansenii strains conserved the ability to assimilate lactose and galactose in the presence of 10% NaCl, while almost all the strains of
Y. lipolytica isolated assimilated citrate and lactate up to 7.5% NaCl.
Y. lipolytica isolates evidenced also the highest proteolytic and lipolytic activities and the capability to catabolize tyrosine producing brown pigment. In addition they resulted in the highest aminobiogenic potential decarboxylating ornithine, phenylalanine, tyrosine and lysine. However, they were not able to produce histamine, biogenic amine produced by three strains of
D. hansenii.
Abstract
Carotenoids represent large group of various natural pigments ensuring typical coloration of plants, microorganisms and several animals. It was confirmed by many studies, that consuming ...these biological active compounds has positive impact for human life. Therefore, they are applied in different industrial fields, such as pharmacy, cosmetic, food, and feed industry. Due to high demand for carotenoids we would like to discover new microorganisms overproducing carotenoids. We focused on yeasts of genus
Rhodotorula sp.
(forty isolates), that we screened according to growth and carotenoid production on Petri dishes and production media. After cultivation on Petri dishes we selected five strains (denoted as KF-4, KF-6, KF-24, KF-31, KF-104) with interesting pigment production and quick growth. The secondary screening on production media identified KF-104 as the best producer of carotenoid pigments with massive pigment accumulation (1.15 mg/g DCW) and yield (9.69 mg/L). The main carotenoid of KF-104 isolate was β-carotene (35.4 %) with the accumulation of 408.7 μg/g DCW and the yield of 3.4 mg/L. The rest were torularhodin, torulene and γ-carotene (62.7–79.0 %). Production of torularhodin in the cells was low (0.4 to 1.4 mg/L) as was its accumulation in cells (31.2–121.0 μg/g DCW). We continue the experimental analyses of these isolates in order understand differences in the content of individual pigments.
Stachybotrys was found to be associated with idiopathic pulmonary hemorrhage in infants in Cleveland, Ohio. Since that time, considerable effort has been put into finding the toxic components ...responsible for the disease. The name Stachybotrys chartarum has been applied to most of these isolates, but inconsistent toxicity results and taxonomic confusion prompted the present study. In this study, 122 Stachybotrys isolates, mainly from water-damaged buildings, were characterized and identified by combining three different approaches: morphology, colony characteristics, and metabolite production. Two different Stachybotrys taxa, S. chartarum and one undescribed species, were found in water-damaged buildings regardless of whether the buildings were in Denmark, Finland, or the USA. Furthermore, two chemotypes could be distinguished in S. chartarum. One chemotype produced atranones, whereas the other was a macrocyclic trichothecene-producer. The second undescribed taxon produced atranones and could be differentiated from S. chartarum by its growth characteristics and pigment production. Our results correlate with different inflammatory and toxicological properties reported for these same isolates and show that the three taxa/chemotypes should be treated separately. The co-occurrence of these three taxa/chemotypes in water-damaged buildings explains the inconsistent results in the literature concerning toxicity of Stachybotrys isolated from that environment.
Phosphomannose isomerases (PMIs) in bacteria and fungi catalyze the reversible conversion of
d
-fructose-6-phosphate to
d
-mannose-6-phosphate during biosynthesis of GDP-mannose, which is the main ...intermediate in the mannosylation of important cell wall components, glycoproteins, and certain glycolipids. In the present study, the kinetic parameters of PMI from
Streptomyces coelicolor
were obtained, and its function on antibiotic production and sporulation was studied.
manA
(SCO3025) encoding PMI in
S
.
coelicolor
was deleted by insertional inactivation. Its mutant (
S
.
coelicolor
∆
manA
) was found to exhibit a
bld
-like phenotype. Additionally,
S
.
coelicolor
∆
manA
failed to produce the antibiotics actinorhodin and red tripyrolle undecylprodigiosin in liquid media. To identify the function of
manA
, the gene was cloned and expressed in
Escherichia coli
BL21 (DE3). The purified recombinant ManA exhibited PMI activity (
K
cat
/
K
m
(mM
−1
s
−1
= 0.41 for
d
-mannose-6-phosphate), but failed to show GDP-
d
-mannose pyrophosphorylase GMP (ManC) activity. Complementation analysis with
manA
from
S
.
coelicolor
or
E
.
coli
resulted in the recovery of
bld
-like phenotype of
S
.
coelicolor
∆
manA
. SCO3026, another ORF that encodes a protein with sequence similarity towards bifunctional PMI and GMP, was also tested for its ability to function as an alternate ManA. However, the purified protein of SCO3026 failed to exhibit both PMI and GMP activity. The present study shows that enzymes involved in carbohydrate metabolism could control cellular differentiation as well as the production of secondary metabolites.
In the context of geoarchaeological investigations on Easter Island several hundred human-made pits filled with reddish silty material were discovered in fluvial terraces of two valleys on the ...southern slope of Maunga Terevaka, the highest volcano of the island. Micromorphological analysis of one representative pit filling and comparison of its geochemical and physical properties with sediments in the surrounding terrace was performed in order to reconstruct the probable formation and use of the material in the pits. A hypothesis of pigment production by heating of minerogenic iron-rich substrate with grass fuel resulting in formation of hematite is suggested. It is assumed that the pits represented the places for production and storage of the pigments, which were used by Rapa Nui for cultural and ritual purposes. The ongoing interdisciplinary research will enhance the interpretation of the pits and their fillings and contribute to a better understanding of cultural development on Easter Island.
In this paper, a comprehensive spatio-spectral and temporal analysis for
Chromobacterium violaceum
colonies is reported. A hyperspectral imaging (HSI) system is used to recover the spectral ...signatures of pigment production in a non-homogeneous media with high spectral resolution and high sensitivity in
vivo
, without destructing the sample. This non-contact sensing technique opens avenues to study the temporal growing of a specific section in the bacterial colony. Further, from a 580 nm and 764 nm spatio-spectral time series, a wild-type and mutant
Chromobacterium violaceum
strains are characterized. Such study provides quantitative information about kinetic parameters of pigment production and bacterial growing.
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