Occurrence of Botryococcus terribilis Komárek & Marvan in a small sandpit lake: The first report from Serbia

Alkaline saline ponds and lakes are habitats with unique biodiversity. The green alga of the genus Botryococcus was accidentally discovered during a micro-algal survey of these habitats in Serbia. Species B. terribilis was found and identified for the first time in Serbia in the small sandpit lake of the Rusanda Nature Park. The first sampling was incomplete due to the unknown origin of the orange-red surface scum. After the identity of the species had been confirmed, three additional samplings were conducted aiming to collect phytoplankton and water samples for physical and chemical analyses. Major anions and cations were analysed in order to characterize the chemical type of sandpit lake, as well as nutrient content. Sandpit lake is an alkaline water body that belongs to sodium bicarbonate chemical type. Morphometric analysis of B. terribilis was performed using light and transmission electron microscopy. B. terribilis was found to be numerous in the phytoplankton community in late autumn and winter. Species from the genus Botryococcus are known as a rich source of different lipids and this discovery can be the first step in the further biotechnological application of this species in sustainable biofuel production.

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A Novel TEM Technique for Characterizing As-Grown CVD Diamond Films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089093 ◽

1991 ◽

Vol 49 ◽

pp. 956-957 ◽

Cited By ~ 1

Author(s):

Z.L. Wang ◽

J. Bentley ◽

R.E. Clausing ◽

L. Heatherly ◽

L.L. Horton

Keyword(s):

Diamond Films ◽

Chemical Vapor ◽

Growth Direction ◽

Dark Field ◽

Growth Surface ◽

Specimen Preparation ◽

Transmission Electron ◽

Diffraction Patterns ◽

First Time ◽

Microstructural Studies

Microstructural studies by transmission electron microscopy (TEM) of diamond films grown by chemical vapor deposition (CVD) usually involve tedious specimen preparation. This process has been avoided with a technique that is described in this paper. For the first time, thick as-grown diamond films have been examined directly in a conventional TEM without thinning. With this technique, the important microstructures near the growth surface have been characterized. An as-grown diamond film was fractured on a plane containing the growth direction. It took about 5 min to prepare a sample. For TEM examination, the film was tilted about 30-45° (see Fig. 1). Microstructures of the diamond grains on the top edge of the growth face can be characterized directly by transmitted electron bright-field (BF) and dark-field (DF) images and diffraction patterns.

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CdSe QD Biosynthesis in Yeast Using Tryptone-Enriched Media and Their Conjugation with a Peptide Hecate for Bacterial Detection and Killing

Nanomaterials ◽

10.3390/nano9101463 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1463 ◽

Cited By ~ 5

Author(s):

Vishma Pratap Sur ◽

Marketa Kominkova ◽

Zaneta Buchtova ◽

Kristyna Dolezelikova ◽

Ondrej Zitka ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Synthesis Process ◽

Synthesis Methods ◽

Bacterial Cells ◽

Cdse Qds ◽

Yeast Saccharomyces Cerevisiae ◽

Shape Distribution ◽

Transmission Electron ◽

A Cell ◽

Physical And Chemical

The physical and chemical synthesis methods of quantum dots (QDs) are generally unfavorable for biological applications. To overcome this limitation, the development of a novel “green” route to produce highly-fluorescent CdSe QDs constitutes a promising substitute approach. In the present work, CdSe QDs were biosynthesized in yeast Saccharomyces cerevisiae using a novel method, where we showed for the first time that the concentration of tryptone highly affects the synthesis process. The optimum concentration of tryptone was found to be 25 g/L for the highest yield. Different methods were used to optimize the QD extraction from yeast, and the best method was found to be by denaturation at 80 °C along with an ultrasound needle. Multiple physical characterizations including transmission electron microscopy (TEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), and spectrophotometry confirmed the optical features size and shape distribution of the QDs. We showed that the novel conjugate of the CdSe QDs and a cell-penetrating peptide (hecate) can detect bacterial cells very efficiently under a fluorescent microscope. The conjugate also showed strong antibacterial activity against vancomycin-resistant Staphylococcus aureus (VRSA), methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli, which may help us to cope with the problem of rising antibiotic resistance.

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Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽

10.3390/min11060611 ◽

2021 ◽

Vol 11 (6) ◽

pp. 611

Author(s):

Celia Marcos ◽

María de Uribe-Zorita ◽

Pedro Álvarez-Lloret ◽

Alaa Adawy ◽

Patricia Fernández ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Crystallite Size ◽

Archaeological Sites ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Infrared And Raman Spectroscopy ◽

First Time ◽

Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

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In vitro biological activity of Hydroclathrus clathratus and its use as an extracellular bioreductant for silver nanoparticle formation

Green Processing and Synthesis ◽

10.1515/gps-2020-0043 ◽

2020 ◽

Vol 9 (1) ◽

pp. 416-428 ◽

Cited By ~ 1

Author(s):

Raghad R. Alzahrani ◽

Manal M. Alkhulaifi ◽

Nouf M. Al-Enazi

Keyword(s):

Biological Activity ◽

Unsaturated Fatty Acids ◽

Multidrug Resistant ◽

Chemical Components ◽

Resistant Bacteria ◽

Transmission Electron ◽

Hydroclathrus Clathratus ◽

Adaptive Nature ◽

First Time

AbstractThe adaptive nature of algae results in producing unique chemical components that are gaining attention due to their efficiency in many fields and abundance. In this study, we screened the phytochemicals from the brown alga Hydroclathrus clathratus and tested its ability to produce silver nanoparticles (AgNPs) extracellularly for the first time. Lastly, we investigated its biological activity against a variety of bacteria. The biosynthesized nanoparticles were characterized by UV-visible spectroscopy, Fourier-transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, and energy-dispersive spectroscopy. The biological efficacy of AgNPs was tested against eighteen different bacteria, including seven multidrug-resistant bacteria. Phytochemical screening of the alga revealed the presence of saturated and unsaturated fatty acids, sugars, carboxylic acid derivatives, triterpenoids, steroids, and other components. Formed AgNPs were stable and ranged in size between 7 and 83 nm and presented a variety of shapes. Acinetobacter baumannii, Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), and MDR A. baumannii were the most affected among the bacteria. The biofilm formation and development assay presented a noteworthy activity against MRSA, with an inhibition percentage of 99%. Acknowledging the future of nano-antibiotics encourages scientists to explore and enhance their potency, notably if they were obtained using green, rapid, and efficient methods.

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The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽

10.3390/ma14102623 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2623

Author(s):

Monika Wójcik-Bania ◽

Jakub Matusik

Keyword(s):

Total Pore Volume ◽

Cross Linking ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

The Cross ◽

Chain Lengths ◽

First Time ◽

Substituent Influence ◽

Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

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Morphological and Ultrastructural Characterization of Hemocytes in an Insect Model, the Hematophagous Dipetalogaster maxima (Hemiptera: Reduviidae)

Insects ◽

10.3390/insects12070640 ◽

2021 ◽

Vol 12 (7) ◽

pp. 640

Author(s):

Natalia R. Moyetta ◽

Fabián O. Ramos ◽

Jimena Leyria ◽

Lilián E. Canavoso ◽

Leonardo L. Fruttero

Keyword(s):

Cell Biology ◽

Cell Types ◽

Transmission Electron ◽

Ultrastructural Characterization ◽

Current Classification ◽

Contrast Microscopy ◽

First Time ◽

Controversial Aspect

Hemocytes, the cells present in the hemolymph of insects and other invertebrates, perform several physiological functions, including innate immunity. The current classification of hemocyte types is based mostly on morphological features; however, divergences have emerged among specialists in triatomines, the insect vectors of Chagas’ disease (Hemiptera: Reduviidae). Here, we have combined technical approaches in order to characterize the hemocytes from fifth instar nymphs of the triatomine Dipetalogaster maxima. Moreover, in this work we describe, for the first time, the ultrastructural features of D. maxima hemocytes. Using phase contrast microscopy of fresh preparations, five hemocyte populations were identified and further characterized by immunofluorescence, flow cytometry and transmission electron microscopy. The plasmatocytes and the granulocytes were the most abundant cell types, although prohemocytes, adipohemocytes and oenocytes were also found. This work sheds light on a controversial aspect of triatomine cell biology and physiology setting the basis for future in-depth studies directed to address hemocyte classification using non-microscopy-based markers.

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Direct TEM observation of the “acanthite α-Ag2S–argentite β-Ag2S” phase transition in a silver sulfide nanoparticle

Nanoscale Advances ◽

10.1039/c8na00347e ◽

2019 ◽

Vol 1 (4) ◽

pp. 1581-1588 ◽

Cited By ~ 6

Author(s):

S. I. Sadovnikov ◽

E. Yu. Gerasimov

Keyword(s):

Electron Microscopy ◽

Phase Transition ◽

Transmission Electron Microscopy ◽

Silver Sulfide ◽

Transmission Electron ◽

Silver Sulfide Nanoparticles ◽

Microscopy Method ◽

Electron Microscopy Method ◽

First Time

For the first time, the α-Ag2S (acanthite)–β-Ag2S (argentite) phase transition in a single silver sulfide nanoparticles has been observed in situ using a high-resolution transmission electron microscopy method in real time.

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The Influence Of NO/O2 On The NOx Storage Properties Over A Pt-Ba-Ce/γ-Al2O3 Catalyst

Open Chemistry ◽

10.1515/chem-2019-0153 ◽

2019 ◽

Vol 17 (1) ◽

pp. 1459-1465

Author(s):

Xuedong Feng ◽

Jing Yi ◽

Peng Luo

Keyword(s):

Sol Gel ◽

Chemical Properties ◽

No Oxidation ◽

Test Results ◽

X Ray Diffraction ◽

Storage Performance ◽

Transmission Electron ◽

Temperature Programmed ◽

Physical And Chemical ◽

Al2o3 Catalyst

AbstractWith the purpose of studying the influence of NO/O2 on the NOx storage activity, a Pt-Ba-Ce/γ-Al2O3 catalyst was synthesized by an acid-aided sol-gel method. The physical and chemical properties of the catalyst were characterized by X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) methods. The results showed that the composition of the catalyst was well-crystallized and the crystalline size of CeO2 (111) was about 5.7 nm. The mechanism of NO and NO2 storage and NOx temperature programmed desorption (NO-TPD) experiments were investigated to evaluate the NOx storage capacity of the catalyst. Pt-Ba-Ce/γ-Al2O3 catalyst presented the supreme NOx storage performance at 350℃, and the maximum value reached to 668.8 μmol / gcat. Compared with O2-free condition, NO oxidation to NO2 by O2 had a beneficial effect on the storage performance of NOx. NO-TPD test results showed that the NOx species stored on the catalyst surface still kept relatively stable even below 350℃.

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Mesoscopic characterization of the optical property of antiphase boundaries in CuPt-ordered GaInP2

MRS Proceedings ◽

10.1557/proc-588-105 ◽

1999 ◽

Vol 588 ◽

Author(s):

Y. Ohno ◽

S. Takeda

Keyword(s):

Optical Property ◽

Light Emission ◽

Polarized Light ◽

Structural Data ◽

Luminescence Spectra ◽

Antiphase Boundaries ◽

Transmission Electron ◽

Tem Method ◽

Low Dimensional ◽

First Time

AbstractWe have developed an apparatus for polarized cathodoluminescence (CL) spectroscopy combined with transmission electron microscopy (TEM), that enables us to obtain simultaneously structural data in higher spatial resolution by TEM and polarized luminescence spectra by CL of the same microscopic area. The polarized-CL/TEM method is very useful to study the optical properties of low-dimensional microstructures in semiconducting materials. We have applied the method to examine the optical property of antiphase boundaries in CuPt-ordered GaInP2 and found, for the first time, the polarized light emission from the APBs whose habit planes are parallel to the (T11) and (1T0) atomic planes.

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TRANSMISSION ELECTRON MICROSCOPY OF SURFACE AND INTERFACIAL STEPS

Surface Review and Letters ◽

10.1142/s0218625x97000547 ◽

1997 ◽

Vol 04 (03) ◽

pp. 559-566 ◽

Cited By ~ 1

Author(s):

J. M. GIBSON ◽

X. CHEN ◽

O. POHLAND

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Free Surface ◽

Significant Loss ◽

Stress Fields ◽

Preliminary Results ◽

Surface Steps ◽

Transmission Electron ◽

First Time

Transmission electron microscopy is uniquely able to extend techniques for imaging free surface steps to the buried interface regime, without significant loss of detail. Two mechanisms for imaging surface and interfacial steps by transmission electron microscopy are described. They are thickness contrast and strain contrast. The former reveals the position and approximate height of steps, whereas the latter detects stress fields which are commonly associated with steps. The basis for each of these methods is elaborated, and preliminary results are shown for step images at Si/SiO2 interfaces, where measurable stress fields have been directly detected for the first time.

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