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1.
In this study, mineralization during brick preparation was performed with ureolytic bacterium, Lysinibacillus fusiformis that use urine as a substrate, omitting the heat that is normally required. Artificial urine for reasons of standardization was used to grow the bacterium for bio-bricks made of clay and cement, but their mineralization was enabled by biological activity instead of by heat. Scanning electron microscopy and energy dispersion X-ray spectroscopy were conducted to analyse the microstructures formed by L. fusiformis that precipitated various minerals in synthetic urine. The brick specimens were tested for compressive strength that was 59% more than control ones, whereas porosity of bio-bricks was 13% compared to 22% of control specimens. The minerals formed in the bio-bricks confirmed as struvite, apatite and calcite by Fourier-transform infrared spectroscopy and X-ray diffraction spectra, were responsible for improved strength and reduced porosity. The research provided evidence in utilizing ureolytic bacteria as a mode to mineralize clay in brick production with the use of (artificial) urine as a substrate.  相似文献   

2.
Extraction of Carnegiea gigantea yielded a new 3,4-dihydroisoquinoline alkaloid, dehydroheliamine; the structure was confirmed by synthesis.  相似文献   

3.
The World Conservation Union (IUCN) Red List of Threatened Species is an important instrument to evaluate the conservation status of living organisms. However, Red List assessors have been limited by the lack of reliable methods to calculate the area of occupancy (AOO) of species, which is an important parameter for red list assessments. Here we present a new practical method to estimate AOO based on herbarium specimen data: the Cartographic method by Conglomerates (CMC). This method, which combines elements from the Areographic and Cartographic methods previously used to calculate AOO, was tested with ten cactus species from the Chihuahuan Desert Region. The results derived from this novel procedure produced in average AOO calculations 3.5 and 5.5 smaller than the Areographic and Cartographic methods, respectively. The CMC takes into account the existence of disjunctions in the distribution range of the species, producing comparatively more accurate AOO estimations. Another advantage of the CMC is that it generates results more harmonic with the current Red List criteria. In contrast, the overestimated results of the Areographic and Cartographic methods tend to artificially categorize the species, even extremely narrow endemics, in lower endangerment status.  相似文献   

4.
A new subspecies ofConsolea millspaughii is described from the eastern bluff of Cayman Brac and northern coastal terrace of Little Cayman (Cayman Islands, British West Indies). This taxon has been mistakenly identified asConsolea spinosissima since its first collection in 1938. However, the smooth surface of its stem segments, not being demarcated by a network of depressed lines, its pitted areoles, and the fairly reduced pedicellate area of the pericarpel set is apart from this Jamaican endemic. Because the novelty here described brings to three the number ofConsolea taxa that are characterized by very closely set, pitted areoles, an informal “C. millspaughii species-group” is recognized. This assemblage of Western Caribbean opuntioids includesConsolea corallicola, C. millspaughii subsp.millspaughii, andC. millspaughii subsp.caymannnsis. The new subspecies is described, illustrated, and compared withC. spinosissima and with kindred taxa within the species-group. A key to all species and subspecies ofConsolea is provided.  相似文献   

5.
The nacreous layer of pearl oysters is one of the major biominerals of commercial and industrial interest. Jacalin‐related lectins, including PPL3 isoforms, are known to regulate biomineralization of the Pteria penguin pearl shell, although the molecular mechanisms are largely unknown. The PPL3 crystal structures were determined partly by utilizing microgravity environments for 3 isoforms, namely, PPL3A, PPL3B, and PPL3C. The structures revealed a tail‐to‐tail dimer structure established by forming a unique inter‐subunit disulfide bond at C‐termini. The N‐terminal residues were found in pyroglutamate form, and this was partly explained by the post‐translational modification of PPL3 isoforms implied from the discrepancy between amino acid and gene sequences. The complex structures with trehalose and isomaltose indicated that the novel specificity originated from the unique α‐helix of PPL3 isoforms. Docking simulations of PPL3B to various calcite crystal faces suggested the edge of a β‐sheet and the carbohydrate‐binding site rich in charged residues were the interface to the biomineral, and implied that the isoforms differed in calcite interactions.  相似文献   

6.
7.
A recently developed ultra‐resolving near‐field infrared nanoscope is applied to investigate methyl methacrylate embedded, un‐decalcified human bone sections. Results show detail at a resolution of 30 nm. Specific contrasting of mineral components is enabled by choosing an appropriate infrared wavelength, here 9.47 μm, in the phosphate vibrational band. The method is surface‐sensitive, probing to a depth of about 30 nm into the surface. The obtained infrared images are presented in direct comparison with optical and electron micrographs of the identical specimen. Lamellar bone organization, peri‐cellular mineral deposition, and regional differences in mineral content are clearly detectable. Individual fibrils are resolved. – Infrared nanoscopy requires just standard hard tissue preparation techniques combined with section surface polishing. It can be integrated into existing laboratory environments without impeding subsequent routine staining and evaluation methods. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

8.
9.
Structure-function relationships in highly modified shoots of cactaceae   总被引:1,自引:0,他引:1  
BACKGROUND AND AIMS: Cacti are extremely diverse structurally and ecologically, and so modified as to be intimidating to many biologists. Yet all have the same organization as most dicots, none differs fundamentally from Arabidopsis or other model plants. This review explains cactus shoot structure, discusses relationships between structure, ecology, development and evolution, and indicates areas where research on cacti is necessary to test general theories of morphogenesis. SCOPE: Cactus leaves are diverse; all cacti have foliage leaves; many intermediate stages in evolutionary reduction of leaves are still present; floral shoots often have large, complex leaves whereas vegetative shoots have microscopic leaves. Spines are modified bud scales, some secrete sugar as extra-floral nectaries. Many cacti have juvenile/adult phases in which the flowering adult phase (a cephalium) differs greatly from the juvenile; in some, one side of a shoot becomes adult, all other sides continue to grow as the juvenile phase. Flowers are inverted: the exterior of a cactus 'flower' is a hollow vegetative shoot with internodes, nodes, leaves and spines, whereas floral organs occur inside, with petals physically above stamens. Many cacti have cortical bundles vascularizing the cortex, however broad it evolves to be, thus keeping surface tissues alive. Great width results in great weight of weak parenchymatous shoots, correlated with reduced branching. Reduced numbers of shoot apices is compensated by great increases in number of meristematic cells within individual SAMs. Ribs and tubercles allow shoots to swell without tearing during wet seasons. Shoot epidermis and cortex cells live and function for decades then convert to cork cambium. Many modifications permit water storage within cactus wood itself, adjacent to vessels.  相似文献   

10.
Ethylenediamine-tetraacetic acid extracted water-soluble matrix proteins in molluscan shells secreted from the mantle epithelia are believed to control crystal nucleation, morphology, orientation, and phase of the deposited mineral. Previously, atomic force microscopy demonstrated that abalone nacre proteins bind to growing step edges and to specific crystallographic faces of calcite, suggesting that inhibition of calcite growth may be one of the molecular processes required for growth of the less thermodynamically stable aragonite phase. Previous experiments were done with protein mixtures. To elucidate the role of single proteins, we have characterized two proteins isolated from the aragonitic component of nacre of the red abalone, Haliotis rufescens. These proteins, purified by hydrophobic interaction chromatography, are designated AP7 and AP24 (aragonitic protein of molecular weight 7 kDa and 24 kDa, respectively). Degenerate oligonucleotide primers corresponding to N-terminal and internal peptide sequences were used to amplify cDNA clones by a polymerase chain reaction from a mantle cDNA library; the deduced primary amino acid sequences are presented. Preliminary crystal growth experiments demonstrate that protein fractions enriched in AP7 and AP24 produced CaCO(3) crystals with morphology distinct from crystals grown in the presence of the total mixture of soluble aragonite-specific proteins. Peptides corresponding to the first 30 residues of the N-terminal sequences of both AP7 and AP24 were generated. The synthetic peptides frustrate the progression of step edges of a growing calcite surface, indicating that sequence features within the N-termini of AP7 and AP24 include domains that interact with CaCO(3). CD analyses demonstrate that the N-terminal peptide sequences do not possess significant percentages of alpha-helix or beta-strand secondary structure in solution. Instead, in both the presence and absence of Ca(II), the peptides retain unfolded conformations that may facilitate protein-mineral interaction.  相似文献   

11.
The crystallographic orientation of structural elements in skeletons of representatives of Carboniferous Syringoporicae (Auloporida) has been analysed by scanning electron microscopy (SEM), petrographic microscopy and electron backscatter diffraction (EBSD) on specimens from the Iberian Peninsula. The skeletons of the tabulate corals of the Syringoporicae consist of biogenic calcite crystals, and their microstructure is composed of lamellae, fibres and granules, or of a combination of these. Independent of the microstructure, the c‐axis is oriented towards the lumen, quasi‐perpendicular to the growth direction of the skeleton (perpendicular to the morphological axis lamellae, parallel to fibres). Most phaceloid taxa have a turbostratic distribution, as a biogenic response to prevent the cleavage of crystals. Cerioid and some phaceloid corals, whose microstructure is conditioned by wall elements, do not exhibit turbostratic distribution. Wall elements are determined by the biology of each taxon. Holacanth septal spines are composed of fibres arranged in a cone‐shape structure, sometimes clamped to the external part of the corallite and show a complex crystallography. Monacanth septal spines are spindle shaped and composed of bundles of fibres. Tabulae are composed of lamellae. Their development and crystallographic orientation depends on the position of the epithelium in each case. Shared walls are formed by a combination of the walls of two independent corallites with a median lamina, composed of granules; these have a crystallographic orientation between that of the two corallites. The growth of the microstructure is derived by a coordinated stepping mode of growth, similar to other groups of organisms such as molluscs and scleractinians. The nucleation and formation of packages of co‐oriented microcrystals suggest a growth mode similar to mineral bridges with a competitive growth mode between each crystal. The growth pattern of corallites suggests that the growth direction is divided into two main components: a horizontal growth direction towards the lumen and a vertical direction towards the top.  相似文献   

12.
Natural product's properties are related to certain classes of compounds such as alkaloids, flavonoids, essential oils and others. Traditionally, separation techniques including thin layer chromatography (TLC), liquid chromatography (LC), gas chromatography (GC) and capillary electrophoresis (CE) even hyphenated to mass spectrometry (MS) were used for the elucidation, qualitative and quantitative analysis of individual compounds.In food industry, spectroscopic investigations using infrared radiation have been used to monitor and evaluate the composition and quality already since the early sixties. During the last four decades near-infrared spectroscopy (NIR; 800–2500 nm; 12,500–4000 cm−1) has become one of the most attractive and used methods for analysis for the following reasons: it represents a non-invasive analytical tool allowing a fast and simultaneous qualitative and quantitative characterization of natural products and their constituents. Additionally, the development of custom-made hand-held instruments enables in-field measurement for determining the optimum harvest time.Attenuated total reflection (ATR) and Fourier transform infrared (FTIR) spectroscopic imaging are suitable not only for the differentiation of different plant species, but also to distinct various ingredients within a plant. FTIR spectroscopic microscopy enables molecular imaging of complex botanical samples and therefore the detection and characterization of the molecular components of biological tissue.In the present contribution, the principle, technique and methodology of the different infrared spectroscopic methods are described followed by a discussion of quantitative and qualitative application possibilities in the field of natural product analysis.  相似文献   

13.
《MABS-AUSTIN》2013,5(3):649-658
Glycosylation is an important post-translational modification during protein production in eukaryotic cells, and it is essential for protein structure, stability, half-life, and biological functions. In this study, we produced various monoclonal antibody (mAb) glycoforms from Chinese hamster ovary (CHO) cells, including the natively glycosylated antibody, the enriched G0 form, the deglycosylated form, the afucosylated form, and the high mannose form, and we compared their intrinsic properties, side-by-side, through biophysical and biochemical approaches. Spectroscopic analysis indicates no measureable secondary or tertiary structural changes after in vitro or in vivo modification of the glycosylation pattern. Thermal unfolding experiments show that the high mannose and deglycosylated forms have reduced thermal stability of the CH2 domain compared with the other tested glycoforms. We also observed that the individual domain’s thermal stability could be pH dependent. Proteolysis analysis indicates that glycosylation plays an important role in stabilizing mAbs against proteases. The stability of antibody glycoforms at the storage condition (2–8 °C) and at accelerated conditions (30 and 40 °C) was evaluated, and the results indicate that glycosylation patterns do not substantially affect the storage stability of the antibody we studied.  相似文献   

14.
The pattern of calcium carbonate deposition was observed in the dorsal carapace of premolt (D2-D3) and early postmolt (0-48 h) blue crabs, Callinectes sapidus, using scanning (SEM) and transmission (TEM) electron microscopy. Samples of dorsal carapace for SEM were quick-frozen in liquid nitrogen, subsequently lyophilized, and viewed using secondary and backscattered electrons as well as X-ray maps of calcium. Pieces of lyophilized cuticle were also embedded in epoxy resin and subsequently sectioned and viewed with TEM and SEM. Fresh pieces of dorsal carapace for TEM were also fixed in 2.5% glutaraldehyde in phosphate buffer followed by postfixation in 1% OsO4 in cacodylate buffer. Calcium concentrations were determined using atomic absorption spectrophotometry and quantitative X-ray microanalysis. Calcium accumulation began in the cuticle at 3 h postmolt at the epicuticle/exocuticle boundary and at the distal and proximal margins of the interprismatic septa (IPS). The bidirectional calcification of the IPS continued until the two fronts met at 5-8 h postmolt. The roughly hexagonal walls of the IPS formed a honeycomb-like structure that resulted in a rigid cuticle. The walls of the canal containing sensory neurons also calcified at 3 h, thereby imparting rigidity to the structure and additional strength to the cuticle. Examination of thin sections of lyophilized cuticle and fixed cuticle revealed that the first mineral deposited is more soluble than calcite and is probably amorphous calcium carbonate. The amorphous calcium carbonate is transformed to calcite along a front that follows the original deposition and is probably controlled by a specialized matrix within the IPS. Since amorphous calcium carbonate is isotropic, it would also make the mineral in the exocuticle stronger by an equal distribution of mechanical stress.  相似文献   

15.
16.
Characterization of three cactus proteins (native and denatured) from Machaerocereus gummosus (Pitahaya agria), Lophocereu schottii (Garambullo), and Cholla opuntia (Cholla), was based on electrophoretic, fluorescence, CD (circular dichroism), DSC (differential scanning calorimetry), and FT-IR (Fourier transform infrared) measurements. The obtained results of intrinsic fluorescence, DSC, and CD were dissimilar for the three species of cactus, providing evidence of differences in secondary and tertiary structures. Cactus proteins may be situated in the following order corresponding to their relative stability: Machaerocereus gummosus (Pitahaya agria) > Cholla opuntia (Cholla) > Lophocereu schottii (Garambullo). Thermodynamic properties of proteins and their changes upon denaturation (temperature of denaturation, enthalphy, and the number of ruptured hydrogen bonds) were correlated with the secondary structure of proteins and disappearance of -helix.  相似文献   

17.
Glycosylation is an important post-translational modification during protein production in eukaryotic cells, and it is essential for protein structure, stability, half-life, and biological functions. In this study, we produced various monoclonal antibody (mAb) glycoforms from Chinese hamster ovary (CHO) cells, including the natively glycosylated antibody, the enriched G0 form, the deglycosylated form, the afucosylated form, and the high mannose form, and we compared their intrinsic properties, side-by-side, through biophysical and biochemical approaches. Spectroscopic analysis indicates no measureable secondary or tertiary structural changes after in vitro or in vivo modification of the glycosylation pattern. Thermal unfolding experiments show that the high mannose and deglycosylated forms have reduced thermal stability of the CH2 domain compared with the other tested glycoforms. We also observed that the individual domain’s thermal stability could be pH dependent. Proteolysis analysis indicates that glycosylation plays an important role in stabilizing mAbs against proteases. The stability of antibody glycoforms at the storage condition (2–8 °C) and at accelerated conditions (30 and 40 °C) was evaluated, and the results indicate that glycosylation patterns do not substantially affect the storage stability of the antibody we studied.  相似文献   

18.
The field of molecular vibrational spectroscopy applied to natural products is advancing extremely fast. Traditionally applied separation techniques (LC-, μ-LC–MS, GC, CE-MS) offer the advantages of high selectivity/sensitivity, but their application for routine quality control is limited due to long analyses times. Therefore, molecular spectroscopy in combination with multivariate analysis (MVA) enjoys excellent reputation, because of the fast and non-invasive measurement enabling the analysis of several physical and chemical parameters simultaneously. Near infrared (NIR; 4.000–10.000 cm−1), attenuated total reflection (ATR; 400–4.000 cm−1), Raman and far ultraviolet (FUV;120–200 nm) spectroscopy have permanently increased their efficiencies for quality control of predominantly food stuff, but also of other natural products including mainly medicinal plants. All four techniques enable not only a quantitative analysis of potent ingredients, but also qualitative fingerprint analysis for the discrimination of, e.g., species and/or geographic origin, respectively. Thereby, each individual spectroscopic technique possesses its specific strength. Powerful miniaturized portable spectrometers based on linear variable tuneable filter (LVTF) or micro-electro-mechanical systems (MEMS) are helpful in order to prevent consumers from deception on one hand, on the other hand they represent powerful analytical instruments for measurements in the field. 2-Dimensional correlation spectroscopy (2DCOS) represents a powerful technique for monitoring the dynamics of a system including temperature stability, extraction procedures etc. Imaging and mapping spectroscopy using infrared radiation and/or Raman scattering are not only suitable for classification of food stuff including e.g. maize kernels and/or coffee beans, but also for localizing the distribution of ingredients down to a resolution of 4 μm.In the present contribution, the latest progresses of the different techniques are introduced and their applicability in the fields of natural product analysis will be discussed in detail by distinct selected applications.  相似文献   

19.
20.
近红外光谱技术(NIRS)在人体的应用与研究是近年来在国内外新兴的研究领域,因为其方便无创,成本低等优点,近20年来在不断发展和完善,引起大家的广泛关注。近红外光谱在700-900 mm范围内可以穿透一定深度的组织,组织内含氧血红蛋白、去氧血红蛋白对近红外光的吸收系数存在差异,经过传感器和计算机技术分析,得到组织的血氧参数。其测量参数为微动脉、微静脉和毛细血管中血液的血氧参数之加权平均,反应组织中的血氧参数,其中静脉血占主要地位,不同于普通脉搏式血氧监测仪的指端动脉血的血氧饱和度。基于近红外光谱技术的近红外组织血氧无创监测仪、功能性近红外光谱技术(f NIRS)、近红外光谱荧光技术等在临床医学,运动医学,神经生物学,认知科学,脑力疲劳,人机交互等新兴领域正发挥越来越重要作用。  相似文献   

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