scholarly journals Characterization of Extracellular Polymeric Substances from Acidophilic Microbial Biofilms

2010 ◽  
Vol 76 (9) ◽  
pp. 2916-2922 ◽  
Author(s):  
Yongqin Jiao ◽  
George D. Cody ◽  
Anna K. Harding ◽  
Paul Wilmes ◽  
Matthew Schrenk ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Metal Content ◽  
Extracellular Polymeric Substances ◽  
Mine Drainage ◽  
Relative Concentration ◽  
Dry Weight ◽  
Composition Analysis ◽  
Geochemical Environment ◽  
Microbial Biofilms

ABSTRACT We examined the chemical composition of extracellular polymeric substances (EPS) extracted from two natural microbial pellicle biofilms growing on acid mine drainage (AMD) solutions. The EPS obtained from a mid-developmental-stage biofilm (DS1) and a mature biofilm (DS2) were qualitatively and quantitatively compared. More than twice as much EPS was derived from DS2 as from DS1 (approximately 340 and 150 mg of EPS per g [dry weight] for DS2 and DS1, respectively). Composition analyses indicated the presence of carbohydrates, metals, proteins, and minor quantities of DNA and lipids, although the relative concentrations of these components were different for the two EPS samples. EPS from DS2 contained higher concentrations of metals and carbohydrates than EPS from DS1. Fe was the most abundant metal in both samples, accounting for about 73% of the total metal content, followed by Al, Mg, and Zn. The relative concentration profile for these metals resembled that for the AMD solution in which the biofilms grew, except for Si, Mn, and Co. Glycosyl composition analysis indicated that both EPS samples were composed primarily of galactose, glucose, heptose, rhamnose, and mannose, while the relative amounts of individual sugars were substantially different in DS1 and DS2. Additionally, carbohydrate linkage analysis revealed multiply linked heptose, galactose, glucose, mannose, and rhamnose, with some of the glucose in a 4-linked form. These results indicate that the biochemical composition of the EPS from these acidic biofilms is dependent on maturity and is controlled by the microbial communities, as well as the local geochemical environment.

scholarly journals Characterization of Arils Juice and Peel Decoction of Fifteen Varieties of Punica granatum L.: A Focus on Anthocyanins, Ellagitannins and Polysaccharides

Antioxidants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 238 ◽  
Author(s):  
Diletta Balli ◽  
Lorenzo Cecchi ◽  
Mohamad Khatib ◽  
Maria Bellumori ◽  
Francesco Cairone ◽  
...  
Keyword(s):  
Chemical Composition ◽  
High Performance ◽  
Antioxidant Properties ◽  
Dry Weight ◽  
Punica Granatum ◽  
Array Detector ◽  
Anthocyanin Content ◽  
Inhibitory Capacity

Pomegranate is receiving renewed commercial and scientific interest, therefore a deeper knowledge of the chemical composition of the fruits of less studied varieties is required. In this work, juices from arils and decoctions from mesocarp plus exocarp were prepared from fifteen varieties. Samples were submitted to High Performance Liquid Chromatography—Diode Array Detector–Mass Spectrometry, spectrophotometric and colorimetric CIEL*a*b* analyses. Antioxidant, antiradical and metal chelating properties, inhibitory activity against tyrosinase and α-amylase enzymes were also evaluated. All varieties presented the same main phenols; anthocyanins and ellagitannins were widely variable among varieties, with the richest anthocyanin content in the juices from the Wonderful and Soft Seed Maule varieties (approx. 660 mg/L) and the highest ellagitannin content in the peel of the Black variety (approx. 133 mg/g dry matter). A good correlation was shown between the colour hue and the delphinidin/cyanidin ratio in juices (R2 = 0.885). Total polysaccharide yield ranged from 3% to 12% of the peels’ dry weight, with the highest content in the Black variety. Decoctions (24.44–118.50 mg KAE/g) showed better in vitro antioxidant properties and higher inhibitory capacity against tyrosinase than juices (not active-16.56 mg KAE/g); the inhibitory capacity against α-amylase was similar and quite potent for juices and decoctions. Knowledge about the chemical composition of different pomegranate varieties will allow for a more aware use of the different parts of the fruit.

scholarly journals Characterization of the Skin Cultivable Microbiota Composition of the Frog Pelophylax perezi Inhabiting Different Environments

2021 ◽  
Vol 18 (5) ◽  
pp. 2585
Author(s):  
Diogo Neves Proença ◽  
Emanuele Fasola ◽  
Isabel Lopes ◽  
Paula V. Morais
Keyword(s):  
Extracellular Polymeric Substances ◽  
Mine Drainage ◽  
Bacterial Strains ◽  
Amphibian Skin ◽  
Environmental Disturbances ◽  
Polluted Sites ◽  
A Site ◽  
Pelophylax Perezi ◽  
Significant Growth Inhibition

Microorganisms that live in association with amphibian skin can play important roles in protecting their host. Within the scenarios of global change, it is important to understand how environmental disturbances, namely, metal pollution, can affect this microbiota. The aim of this study is to recognize core bacteria in the skin cultivable microbiota of the Perez frog (Pelophylax perezi) that are preserved regardless of the environmental conditions in which the frogs live. The characterization of these isolates revealed characteristics that can support their contributions to the ability of frogs to use metal impacted environments. Frog’s skin swabs were collected from P. perezi populations that inhabit a metal-polluted site and three reference (non-metal polluted) sites. Bacterial strains were isolated, identified, and subjected to an acid mine drainage tolerance (AMD) test, collected upstream from a site heavily contaminated with metals, and tested to produce extracellular polymeric substances (exopolysaccharide, EPS). All frog populations had Acinetobacter in their cutaneous cultivable microbiota. Significant growth inhibition was observed in all bacterial isolates exposed to 75% of AMD. EPS production was considered a characteristic of several isolates. The data obtained is a preliminary step but crucial to sustain that the cultivable microbiota is a mechanism for protecting frogs against environmental contamination.

scholarly journals Characterization of Ni-P coating prepared via electroless deposition on AZ31 magnesium alloy

2017 ◽  
Vol 61 (1) ◽  
pp. 1-6 ◽  
Author(s):  
M. Buchtík ◽  
P. Kosár ◽  
J. Wasserbauer ◽  
P. Doležal
Keyword(s):  
Chemical Composition ◽  
Magnesium Alloy ◽  
Electroless Deposition ◽  
Mechanical Characteristics ◽  
Chemical Properties ◽  
Composition Analysis ◽  
Physico Chemical ◽  
Chemical Composition Analysis ◽  
Scanning Electron

Abstract This work deals with the characterization of Ni–P coating prepared via electroless deposition on wrought AZ31magnesium alloy. For the application of electroless deposition was proposed and optimized a suitable pretreatment process of magnesium alloy surface followed by Ni–P coating in the nickel bath. The chemical composition of Ni–P based coating was characterized using the scanning electron microscope with chemical composition analysis. Next, physico-chemical properties and mechanical characteristics of Ni–P coating were evaluated. The mechanism of corrosion degradation of the coating and the substrate was also studied in this work.

scholarly journals Characterization of natural cellulosic fiber isolated from Malaysian Cymbopogan citratus leaves

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7729-7750
Author(s):  
Zatil Hafila Kamaruddin ◽  
Ridhwan Jumaidin ◽  
Ahmad Ilyas Rushdan ◽  
Mohd Zulkefli Selamat ◽  
Roziela Hanim Alamjuri
Keyword(s):  
Chemical Composition ◽  
Natural Fiber ◽  
Morphological Characteristics ◽  
Crystallinity Index ◽  
Composition Analysis ◽  
Green Composite ◽  
X Ray Diffraction ◽  
First Time ◽  
Cymbopogan Citratus

A novel natural fiber derived from the Cymbopogan citratus plant was investigated for the first time. The characterization of the C. citratus fibers was conducted, and the chemical composition and physical, thermal, mechanical, crystallinity, and morphological characteristics were studied. The chemical composition analysis of Cymbopogan citratus fiber revealed that the suggested fiber was rich in cellulose contents (37.6%). The tensile test of C. citratus fiber demonstrated the fiber’s average tensile strength of 43.81 ± 15.27 MPa and modulus of elasticity of 1.046 ± 0.33 GPa. Further analysis with X-ray diffraction (XRD) confirmed that the crystallinity index of Cymbopogan citratus fiber was 35.2%, and the crystalline size was estimated as 4.28 nm. The Cymbopogan citratus fiber’s thermal stability was investigated via thermogravimetric analysis (TGA) and observed to be thermally stable (230 °C). A morphological investigation was employed on the fiber via a scanning electron microscope (SEM). The morphological study result exhibited that the fiber had a perforated and rough surface with the lumen in the center. Thus, the findings revealed that the Cymbopogan citratus fiber was a promising potential reinforcement for thermoplastic green composite applications.

scholarly journals Chemical Composition of Essential Oil from Dalbergia odorifera Flowers and HPLC Analysis of Tectorigenin in Its Leaves and Branches

2021 ◽  
Vol 25 (03) ◽  
pp. 723-729
Author(s):  
Ziling Mao
Keyword(s):  
Chemical Composition ◽  
High Performance ◽  
Dry Weight ◽  
Volatile Oil ◽  
Weight Basis ◽  
Composition Analysis ◽  
Dalbergia Odorifera ◽  
Main Components ◽  
First Time ◽  
Further Development

Dalbergia odorifera T. Chen, as an important traditional Chinese medicinal plant, has been used in China over a long history. The chemical composition of volatile oil extracted from the D. odorifera flowers is described for the first time here. The volatile oil was extracted by hydro-distillation, and GC-MS was used for the chemical composition analysis. Tectorigenin, an isoflavonoid, was also isolated from the flowers. The structure of tectorigenin was established based on 1H and 13C NMR and HR-ESI-MS spectrometry. The main components of the volatile oil from the flowers were 4-hydroxy-4-methyl-2-pentanone (28.35%), phenethyl alcohol (12.17%), cis-5-ethenyltetrahydro-α, α-5-trimethyl-2-furanmethanol (8.71%), toluene (7.64%), p-xylene (5.93%), benzyl alcohol (5.72%) and ethylbenzene (5.35%). The tectorigenin contents in the xylem, phloem and leaves were determined by high-performance liquid chromatography (HPLC) as 75.44 μg/g, 104.26 μg/g and 393.11 μg/g, respectively, on a dry weight basis and 49.32 μg/g, 51.98 μg/g and 74.45 μg/g, respectively, on a fresh weight basis. The study provides an important theoretical basis for the further development and application of the D. odorifera flowers and tectorigenin. © 2021 Friends Science Publishers

Characterization of frozen hydrated biological specimens by low-loss EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1572-1573
Author(s):  
Songquan Sun ◽  
Richard D. Leapman
Keyword(s):  
Water Content ◽  
Direct Method ◽  
Internal Standard ◽  
Dry Weight ◽  
Dark Field ◽  
Protein Solutions ◽  
Subcellular Compartment ◽  
Differential Shrinkage ◽  
Electron Energy Loss

Analyses of ultrathin cryosections are generally performed after freeze-drying because the presence of water renders the specimens highly susceptible to radiation damage. The water content of a subcellular compartment is an important quantity that must be known, for example, to convert the dry weight concentrations of ions to the physiologically more relevant molar concentrations. Water content can be determined indirectly from dark-field mass measurements provided that there is no differential shrinkage between compartments and that there exists a suitable internal standard. The potential advantage of a more direct method for measuring water has led us to explore the use of electron energy loss spectroscopy (EELS) for characterizing biological specimens in their frozen hydrated state.We have obtained preliminary EELS measurements from pure amorphous ice and from cryosectioned frozen protein solutions. The specimens were cryotransfered into a VG-HB501 field-emission STEM equipped with a 666 Gatan parallel-detection spectrometer and analyzed at approximately −160 C.

ECOLOGICAL AND PHYSIOLOGICAL ASSESSMENT OF CHEMICAL COMPOSITION OF DRINKING TAP WATER IN KHANTY-MANSIYSK AND SALEKHARD

2020 ◽  
pp. 159-167
Author(s):  
V.V. Lapenko ◽  
L.N. Bikbulatova ◽  
E.M. Ternikova
Keyword(s):  
Drinking Water ◽  
Chemical Composition ◽  
Water Samples ◽  
Tap Water ◽  
Iron Concentration ◽  
Absorption Spectrometry ◽  
Northern Region ◽  
Transport Processes ◽  
Magnesium Concentration ◽  
Geochemical Environment

Water is very important for humans, as it is a solvent for metabolic products. Moreover, it is necessary for metabolism, biochemical and transport processes. The elemental status in persons depends on the geochemical environment and consumption of bioelements with food and water. The aim of the paper is to conduct a comprehensive assessment of chemical composition of drinking tap water in Khanty-Mansiysk and Salekhard. Materials and Methods. The chemical composition of 100 samples of drinking tap water was analyzed by atomic absorption spectrometry, spectrophotometry and capillary electrophoresis. All in all, there were 50 samples from Khanty-Mansiysk and 50 samples from Salekhard. The results were compared with Sanitary Rules and Norms 2.1.4.1074-01. Results. Drinking tap water in Salekhard contains a significantly higher concentration of iron, which is much above the maximum allowable concentration, if compared to water samples in Khanty-Mansiysk (p=0.03). In the cities under consideration, the water undergoes high-quality reagent-free treatment. However, the deterioration of the water supply networks in Salekhard is 3 times as high as in Khanty-Mansiysk. Calcium and magnesium concentration in water samples from Khanty-Mansiysk is 5.6 and 3.9 times lower than the MAC; in water samples from Salekhard calcium concentration is 6.3 (p=0.008) and magnesium concentration 4.6 (p<0.001) times lower than the MAC. Conclusion. The consumption of ultra-fresh drinking water leads to low intake of bioelements, which are a part of enzymes contributing to the human antioxidant defense and can result in manifestation of cardiovascular diseases. This is especially true for Salekhard with very soft drinking water and high iron concentration, which excess can exhibit prooxidant properties. Keywords: tap water, bioelements, northern region, antioxidants. Вода является важнейшим соединением для человека: необходима в качестве растворителя продуктов метаболизма и протекания обменных, биохимических и транспортных процессов. Элементный статус организма человека зависит от геохимического окружения и поступления биоэлементов с пищей и водой. Цель. Провести комплексную оценку химического состава водопроводной воды городов Ханты-Мансийск и Салехард. Материалы и методы. Методами атомно-абсорбционной спектрометрии, спектрофотометрии и капиллярного электрофореза проанализирован химический состав 100 проб водопроводной воды: по 50 из Ханты-Мансийска и Салехарда. Результаты сравнивали с СанПиН 2.1.4.1074-01. Результаты. В водопроводной воде Салехарда установлена превышающая ПДК и достоверно более высокая концентрация железа сравнительно с водой Ханты-Мансийска (р=0,03). При условии качественной безреагентной водоподготовки в изучаемых городах это обусловлено изношенностью водопроводных сетей в Салехарде, более чем в 3 раза превышающей этот показатель в Ханты-Мансийске. Концентрация кальция и магния в воде Ханты-Мансийска в 5,6 и 3,9 раза ниже ПДК; в воде Салехарда – в 6,3 (р=0,008) и 4,6 (р<0,001) раза ниже ПДК соответственно. Заключение. Употребление ультрапресной питьевой воды на фоне очень малого поступления с водой биоэлементов, входящих в состав ферментов антиоксидантной защиты организма человека, может привести к манифестации кардиоваскулярных заболеваний. Это особенно актуально для г. Салехарда с очень мягкой питьевой водой с повышенным содержанием железа, избыток которого может проявлять прооксидантные свойства. Ключевые слова: водопроводная вода, биоэлементы, северный регион, антиоксиданты.

scholarly journals Biofilm Formation in Xanthomonas arboricola pv. pruni: Structure and Development

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 546
Author(s):  
Pilar Sabuquillo ◽  
Jaime Cubero
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Environmental Changes ◽  
Nutrient Content ◽  
Infection Process ◽  
Bacterial Attachment ◽  
Key Factors ◽  
Cell Structures ◽  
Microscopy Techniques

Xanthomonasarboricola pv. pruni (Xap) causes bacterial spot of stone fruit and almond, an important plant disease with a high economic impact. Biofilm formation is one of the mechanisms that microbial communities use to adapt to environmental changes and to survive and colonize plants. Herein, biofilm formation by Xap was analyzed on abiotic and biotic surfaces using different microscopy techniques which allowed characterization of the different biofilm stages compared to the planktonic condition. All Xap strains assayed were able to form real biofilms creating organized structures comprised by viable cells. Xap in biofilms differentiated from free-living bacteria forming complex matrix-encased multicellular structures which become surrounded by a network of extracellular polymeric substances (EPS). Moreover, nutrient content of the environment and bacterial growth have been shown as key factors for biofilm formation and its development. Besides, this is the first work where different cell structures involved in bacterial attachment and aggregation have been identified during Xap biofilm progression. Our findings provide insights regarding different aspects of the biofilm formation of Xap which improve our understanding of the bacterial infection process occurred in Prunus spp and that may help in future disease control approaches.

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