scholarly journals Staphylococcus aureus Infects Osteoclasts and Replicates Intracellularly

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Jennifer L. Krauss ◽  
Philip M. Roper ◽  
Anna Ballard ◽  
Chien-Cheng Shih ◽  
James A. J. Fitzpatrick ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bone Tissue ◽  
Bone Structure ◽  
Time Lapse ◽  
High Rate ◽  
Unique Role ◽  
Content Type ◽  
Intracellular Infection ◽  
Receptor Activator ◽  
Survival Assay

ABSTRACT Osteomyelitis (OM), or inflammation of bone tissue, occurs most frequently as a result of bacterial infection and severely perturbs bone structure. OM is predominantly caused by Staphylococcus aureus, and even with proper treatment, OM has a high rate of recurrence and chronicity. While S. aureus has been shown to infect osteoblasts, it remains unclear whether osteoclasts (OCs) are also a target of intracellular infection. Here, we demonstrate the ability of S. aureus to intracellularly infect and divide within OCs. OCs were differentiated from bone marrow macrophages (BMMs) by exposure to receptor activator of nuclear factor kappa-B ligand (RANKL). By utilizing an intracellular survival assay and flow cytometry, we found that at 18 h postinfection the intracellular burden of S. aureus increased dramatically in cells with at least 2 days of RANKL exposure, while the bacterial burden decreased in BMMs. To further explore the signals downstream of RANKL, we manipulated factors controlling OC differentiation, NFATc1 and alternative NF-κB, and found that intracellular bacterial growth correlates with NFATc1 levels in RANKL-treated cells. Confocal and time-lapse microscopy in mature OCs showed a range of intracellular infection that correlated inversely with S. aureus-phagolysosome colocalization. The propensity of OCs to become infected, paired with their diminished bactericidal capacity compared to BMMs, could promote OM progression by allowing S. aureus to evade initial immune regulation and proliferate at the periphery of lesions where OCs are most abundant. IMPORTANCE The inflammation of bone tissue is called osteomyelitis, and most cases are caused by an infection with the bacterium Staphylococcus aureus. To date, the bone-building cells, osteoblasts, have been implicated in the progression of these infections, but not much is known about how the bone-resorbing cells, osteoclasts, participate. In this study, we show that S. aureus can infect osteoclasts and proliferate inside these cells, whereas bone-residing macrophages, immune cells related to osteoclasts, destroy the bacteria. These findings elucidate a unique role for osteoclasts to harbor bacteria during infection, providing a possible mechanism by which bacteria could evade destruction by the immune system.

scholarly journals Staphylococcus aureus infects osteoclasts and replicates intracellularly

2019 ◽  
Author(s):  
Jennifer L Krauss ◽  
Philip M Roper ◽  
Anna Ballard ◽  
Chien-Cheng Shih ◽  
James AJ Fitzpatrick ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Confocal Microscopy ◽  
Bone Tissue ◽  
Post Infection ◽  
Bone Structure ◽  
High Rate ◽  
Therapeutic Interventions ◽  
Intracellular Infection

AbstractOsteomyelitis (OM), or inflammation of bone tissue, occurs most frequently as a result of bacterial infection and severely perturbs bone structure. The majority of OM is caused by Staphylococcus aureus, and even with proper treatment, OM has a high rate of recurrence and chronicity. While S. aureus has been shown to infect osteoblasts, persist intracellularly, and promote the release of pro-osteoclastogenic cytokines, it remains unclear whether osteoclasts (OCs) are also a target of intracellular infection. In this study, we examined the interaction between S. aureus and OCs, demonstrating internalization of GFP-labeled bacteria by confocal microscopy, both in vitro and in vivo. Utilizing an intracellular survival assay and flow cytometry during OC differentiation from bone marrow macrophages (BMMs), we found that the intracellular burden of S. aureus increases after initial infection in cells with at least 2 days of exposure to the osteoclastogenic cytokine receptor activator of nuclear factor kappa-B ligand (RANKL). Presence of dividing bacteria was confirmed via visualization by transmission electron microscopy. In contrast, undifferentiated BMMs, or those treated with interferon-γ or IL-4, had fewer internal bacteria, or no change, respectively, at 18 hours post infection, compared to 1.5 hours post infection. To further explore the signals downstream of RANKL, we manipulated NFATc1 and alternative NF-κB, which controls NFATc1 and other factors affecting OC function, finding that intracellular bacterial growth correlates with NFATc1 levels in RANKL-treated cells. Confocal microscopy in mature OCs showed a range of intracellular infection that correlated inversely with S. aureus and phagolysosome colocalization. The ability of OCs to become infected, paired with their diminished bactericidal capacity compared to BMMs, could promote OM progression by allowing S. aureus to evade initial immune regulation and proliferate at the periphery of lesions where OCs and bone remodeling are most abundant.Author SummaryThe inflammation of bone tissue is called osteomyelitis, and most cases are caused by an infection with the bacterium Staphylococcus aureus. To date, the bone building cells, osteoblasts, have been implicated in the progression of these infections, but not much is known about how the bone resorbing cells, osteoclasts, participate. In this study, we show that S. aureus can infect osteoclasts and proliferate inside these cells, whereas macrophages, immune cells related to osteoclasts, destroy the bacteria. These findings elucidate a unique role for osteoclasts to harbor bacteria during infection, providing a possible mechanism by which bacteria could evade destruction by the immune system. Therapeutic interventions that target osteoclasts specifically might reduce the severity of OM or improve antibiotic responses.

scholarly journals agrDysfunction Affects Staphylococcal Cassette ChromosomemecType-Dependent Clinical Outcomes in Methicillin-Resistant Staphylococcus aureus Bacteremia

2015 ◽  
Vol 59 (6) ◽  
pp. 3125-3132 ◽  
Author(s):  
Chang Kyung Kang ◽  
Jeong Eun Cho ◽  
Yoon Jeong Choi ◽  
Younghee Jung ◽  
Nak-Hyun Kim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
South Korea ◽  
Clinical Outcomes ◽  
Tertiary Care ◽  
High Rate ◽  
Care Hospital ◽  
Virulence Determinants ◽  
Methicillin Resistant ◽  
Content Type ◽  
Type Iv

ABSTRACTStaphylococcal cassette chromosomemecelement (SCCmec) type-dependent clinical outcomes may vary due to geographical variation in the presence of virulence determinants. We compared the microbiological factors and mortality attributed to methicillin-resistantStaphylococcus aureus(MRSA) bacteremia between SCCmectypes II/III and type IV. All episodes of MRSA bacteremia in a tertiary-care hospital (South Korea) over a 4.5-year period were reviewed. We studied the microbiological factors associated with all blood MRSA isolates, includingspatype,agrtype,agrdysfunction, and the genes for Panton-Valentine leukocidin (PVL) and phenol-soluble modulin (PSM)-mec, in addition to SCCmectype. Of 195 cases, 137 involved SCCmectypes II/III, and 58 involved type IV. The mortality attributed to MRSA bacteremia was less frequent among the SCCmectype IV (5/58) than that among types II/III (39/137,P= 0.002). This difference remained significant when adjusted for clinical factors (adjusted odds ratio [aOR], 0.14; 95% confidence interval [CI], 0.04 to 0.49;P= 0.002). Of the microbiological factors tested,agrdysfunction was the only significant factor that showed different positivity between the SCCmectypes, and it was independently associated with MRSA bacteremia-attributed mortality (aOR, 4.71; 95% CI, 1.72 to 12.92;P= 0.003). SCCmectype IV is associated with lower MRSA bacteremia-attributed mortality than are types II/III, which might be explained by the high rate ofagrdysfunction in SCCmectypes II/III in South Korea.

scholarly journals The Staphylococcus aureus AirSR Two-Component System Mediates Reactive Oxygen Species Resistance via Transcriptional Regulation of Staphyloxanthin Production

2016 ◽  
Vol 85 (2) ◽  
Author(s):  
Jeffrey W. Hall ◽  
Junshu Yang ◽  
Haiyong Guo ◽  
Yinduo Ji
Keyword(s):  
Staphylococcus Aureus ◽  
Wild Type Strain ◽  
Response Regulator ◽  
Opportunistic Pathogen ◽  
Two Component System ◽  
Content Type ◽  
Sigma Factor B ◽  
Survival Assay ◽  
Culturing Conditions ◽  
Gram Positive Cocci

ABSTRACT Staphylococcus aureus is an important opportunistic pathogen and is the etiological agent of many hospital- and community-acquired infections. The golden pigment, staphyloxanthin, of S. aureus colonies distinguishes it from other staphylococci and related Gram-positive cocci. Staphyloxanthin is the product of a series of biosynthetic steps that produce a unique membrane-embedded C30 golden carotenoid and is an important antioxidant. We observed that a strain with an inducible airR overexpression cassette had noticeably increased staphyloxanthin production compared to the wild-type strain under aerobic culturing conditions. Further analysis revealed that depletion or overproduction of the AirR response regulator resulted in a corresponding decrease or increase in staphyloxanthin production and susceptibility to killing by hydrogen peroxide, respectively. Furthermore, the genetic elimination of staphyloxanthin during AirR overproduction abolished the protective phenotype of increased staphyloxanthin production in a whole-blood survival assay. Promoter reporter and gel shift assays determined that the AirR response regulator is a direct positive regulator of the staphyloxanthin-biosynthetic operon, crtOPQMN, but is epistatic to alternative sigma factor B. Taken together, these data indicate that AirSR positively regulates the staphyloxanthin-biosynthetic operon crtOPQMN, promoting survival of S. aureus in the presence of oxidants.

scholarly journals Antimicrobial-Related Severe Adverse Events during Treatment of Bone and Joint Infection Due to Methicillin-Susceptible Staphylococcus aureus

2013 ◽  
Vol 58 (2) ◽  
pp. 746-755 ◽  
Author(s):  
Florent Valour ◽  
Judith Karsenty ◽  
Anissa Bouaziz ◽  
Florence Ader ◽  
Michel Tod ◽  
...  
Keyword(s):  
Risk Factors ◽  
Staphylococcus Aureus ◽  
Adverse Events ◽  
Joint Infection ◽  
Binary Logistic Regression ◽  
Chronic Arthritis ◽  
High Rate ◽  
Content Type ◽  
Joint Infections ◽  
Severe Adverse Events

ABSTRACTProlonged antimicrobial therapy is recommended for methicillin-susceptibleStaphylococcus aureus(MSSA) bone and joint infections (BJI), but its safety profile and risk factors for severe adverse events (SAE) in clinical practice are unknown. We addressed these issues in a retrospective cohort study (2001 to 2011) analyzing antimicrobial-related SAE (defined according to the Common Terminology Criteria for Adverse Events) in 200 patients (male, 62%; median age, 60.8 years [interquartile range {IQR}, 45.5 to 74.2 years]) with MSSA BJI admitted to a reference regional center with acute (66%) or chronic arthritis (7.5%), osteomyelitis (9.5%), spondylodiscitis (16%), or orthopedic device-related infections (67%). These patients received antistaphylococcal therapy for a median of 26.6 weeks (IQR, 16.8 to 37.8 weeks). Thirty-eight SAE occurred in 30 patients (15%), with a median time delay of 34 days (IQR, 14.75 to 60.5 days), including 10 patients with hematologic reactions, 9 with cutaneomucosal reactions, 6 with acute renal injuries, 4 with hypokalemia, and 4 with cholestatic hepatitis. The most frequently implicated antimicrobials were antistaphylococcal penicillins (ASP) (13 SAE/145 patients), fluoroquinolones (12 SAE/187 patients), glycopeptides (9 SAE/101 patients), and rifampin (7 SAE/107 patients). Kaplan-Meier curves and stepwise binary logistic regression analyses were used to determine the risk factors for the occurrence of antimicrobial-related SAE. Age (odds ratio [OR], 1.479 for 10-year increase; 95% confidence interval [CI], 1.116 to 1.960;P= 0.006) appeared to be the only independent risk factor for SAE. In patients receiving ASP or rifampin, daily dose (OR, 1.028; 95% CI, 1.006 to 1.051;P= 0.014) and obesity (OR, 8.991; 95% CI, 1.453 to 55.627;P= 0.018) were associated with the occurrence of SAE. The high rate of SAE and their determinants highlighted the importance of the management and follow-up of BJI, with particular attention to be paid to older persons, especially for ASP dosage, and to rifampin dose adjustment in obese patients.

scholarly journals A Human Osteocyte Cell Line Model for Studying Staphylococcus aureus Persistence in Osteomyelitis

2021 ◽  
Vol 11 ◽  
Author(s):  
Nicholas J. Gunn ◽  
Anja R. Zelmer ◽  
Stephen P. Kidd ◽  
Lucian B. Solomon ◽  
Eugene Roscioli ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Line ◽  
Host Cells ◽  
High Rate ◽  
Infection Model ◽  
Osteosarcoma Cell ◽  
Cell Type ◽  
Line Model ◽  
Intracellular Infection ◽  
Cell Line Model

Infectious osteomyelitis associated with periprosthetic joint infections is often recalcitrant to treatment and has a high rate of recurrence. In the case of Staphylococcus aureus, the most common pathogen in all forms of osteomyelitis, this may be attributed in part to residual intracellular infection of host cells, yet this is not generally considered in the treatment strategy. Osteocytes represent a unique cell type in this context due to their abundance, their formation of a syncytium throughout the bone that could facilitate bacterial spread and their relative inaccessibility to professional immune cells. As such, there is potential value in studying the host-pathogen interactions in the context of this cell type in a replicable and scalable in vitro model. Here, we examined the utility of the human osteosarcoma cell line SaOS2 differentiated to an osteocyte-like stage (SaOS2-OY) as an intracellular infection model for S. aureus. We demonstrate that S. aureus is capable of generating stable intracellular infections in SaOS2-OY cells but not in undifferentiated, osteoblast-like SaOS2 cells (SaOS2-OB). In SaOS2-OY cells, S. aureus transitioned towards a quasi-dormant small colony variant (SCV) growth phenotype over a 15-day post-infection period. The infected cells exhibited changes in the expression of key immunomodulatory mediators that are consistent with the infection response of primary osteocytes. Thus, SaOS2-OY is an appropriate cell line model that may be predictive of the interactions between S. aureus and human osteocytes, and this will be useful for studying mechanisms of persistence and for testing the efficacy of potential antimicrobial strategies.

scholarly journals Fitness Cost Evolution of Natural Plasmids of Staphylococcus aureus

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pedro Dorado-Morales ◽  
M. Pilar Garcillán-Barcia ◽  
Iñigo Lasa ◽  
Cristina Solano
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Bacterial Pathogen ◽  
Fitness Cost ◽  
High Rate ◽  
Insertion Sequences ◽  
New Host ◽  
Content Type ◽  
Antimicrobial Resistance Genes

ABSTRACT Plasmids have largely contributed to the spread of antimicrobial resistance genes among Staphylococcus strains. Knowledge about the fitness cost that plasmids confer on clinical staphylococcal isolates and the coevolutionary dynamics that drive plasmid maintenance is still scarce. In this study, we aimed to analyze the initial fitness cost of plasmids in the bacterial pathogen Staphylococcus aureus and the plasmid-host adaptations that occur over time. For that, we first designed a CRISPR (clustered regularly interspaced palindromic repeats)-based tool that enables the removal of native S. aureus plasmids and then transferred three different plasmids isolated from clinical S. aureus strains to the same-background clinical cured strain. One of the plasmids, pUR2940, obtained from a livestock-associated methicillin-resistant S. aureus (LA-MRSA) ST398 strain, imposed a significant fitness cost on both its native and the new host. Experimental evolution in a nonselective medium resulted in a high rate pUR2940 loss and selected for clones with an alleviated fitness cost in which compensatory adaptation occurred via deletion of a 12.8-kb plasmid fragment, contained between two ISSau10 insertion sequences and harboring several antimicrobial resistance genes. Overall, our results describe the relevance of plasmid-borne insertion sequences in plasmid rearrangement and maintenance and suggest the potential benefits of reducing the use of antibiotics both in animal and clinical settings for the loss of clinical multidrug resistance plasmids. IMPORTANCE Plasmids are major agents in the spread of antibiotic resistance genes among bacteria. How plasmids and their hosts coevolve to reduce the fitness cost associated with plasmid carriage when bacteria grow in an antibiotic-free environment is not well understood. Here, we investigated the cost and the genetic adaptations that occur during evolution in the absence of antibiotics when the bacterial pathogen Staphylococcus aureus acquires a new plasmid. Our results show the occurrence, at the end of evolution, of plasmid rearrangements mediated by insertion sequences that lead to the loss of antimicrobial resistance genes from the plasmid and an alleviated fitness cost. Our results thus highlight the probable benefits of reducing the use of antibiotics in management programs for the selection of S. aureus clones carrying plasmids that no longer confer resistance.

scholarly journals High Rate ofqacA- andqacB-Positive Methicillin-Resistant Staphylococcus aureus Isolates from Chlorhexidine-Impregnated Catheter-Related Bloodstream Infections

2012 ◽  
Vol 56 (11) ◽  
pp. 5693-5697 ◽  
Author(s):  
Cheng-Mao Ho ◽  
Chi-Yuan Li ◽  
Mao-Wang Ho ◽  
Chien-Yu Lin ◽  
Shu-Hui Liu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Case Control Study ◽  
Significant Risk ◽  
Bloodstream Infections ◽  
High Rate ◽  
Methicillin Resistant ◽  
Content Type ◽  
Resistant Genes ◽  
Control Study

ABSTRACTChlorhexidine has been widely used for infection control. Although the use of chlorhexidine-impregnated catheters has reduced catheter-related infections, chlorhexidine-resistantStaphylococcus aureushas emerged. The correlation between the existence of the chlorhexidine-resistant genesqacAandqacB(qacA/B) in methicillin-resistantStaphylococcus aureus(MRSA) isolates and the effectiveness of chlorhexidine-impregnated catheters in the prevention of MRSA infections is unknown. Sixty methicillin-sensitiveStaphylococcus aureus(MSSA) and 96 MRSA isolates from the blood cultures of different patients were collected, and a case-control study was conducted to determine whether more clinicalS. aureusisolates from chlorhexidine-impregnated catheter-related bloodstream infections (CRBSI) have the biocide-resistant genes (qacA/Borsmr) than those from other infections. The chlorhexidine MIC50s of MSSA and MRSA isolates were 1 μg/ml and 2 μg/ml, respectively. Results of PCR analyses showed that 3.3% (n= 2) of MSSA and 43.8% (n= 42) of MRSA isolates harboredqacA/Band 5% (n= 3) of MSSA and 25% (n= 24) of MRSA isolates containedsmr. With multivariate logistic regression analyses, the significant risk factors for definite CRBSI with chlorhexidine-impregnated catheters were determined to beS. aureusisolates withqacA/Band a chlorhexidine MIC of ≥2 μg/ml (odds ratios [OR], 9.264 and 8.137, respectively, in all 156S. aureusisolates and 6.097 and 4.373, respectively, in the 96 MRSA isolates). Further prospective studies are needed to investigate the transmission of these biocide-resistant genes.

scholarly journals Use of Microfluidic Technology To Analyze Gene Expression during Staphylococcus aureus Biofilm Formation Reveals Distinct Physiological Niches

2013 ◽  
Vol 79 (11) ◽  
pp. 3413-3424 ◽  
Author(s):  
Derek E. Moormeier ◽  
Jennifer L. Endres ◽  
Ethan E. Mann ◽  
Marat R. Sadykov ◽  
Alexander R. Horswill ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Molecular Mechanisms ◽  
Fluorescent Protein ◽  
Time Lapse ◽  
Microfluidic System ◽  
Fluorescent Reporter ◽  
Content Type ◽  
Biofilm Development

ABSTRACTTheStaphylococcus aureus cidandlrgoperons play significant roles in the control of autolysis and accumulation of extracellular genomic DNA (eDNA) during biofilm development. Although the molecular mechanisms mediating this control are only beginning to be revealed, it is clear that cell death must be limited to a subfraction of the biofilm population. In the present study, we tested the hypothesis thatcidandlrgexpression varies during biofilm development as a function of changes in the availability of oxygen. To examinecidandlrgpromoter activity during biofilm development, fluorescent reporter fusion strains were constructed and grown in a BioFlux microfluidic system, generating time-lapse epifluorescence images of biofilm formation, which allows the spatial and temporal localization of gene expression. Consistent withcidinduction under hypoxic conditions, thecid::gfpfusion strain expressed green fluorescent protein predominantly within the interior of the tower structures, similar to the pattern of expression observed with a strain carrying agfpfusion to the hypoxia-induced promoter controlling the expression of the lactose dehydrogenase gene. Thelrgpromoter was also expressed within towers but appeared more diffuse throughout the tower structures, indicating that it was oxygen independent. Unexpectedly, the results also demonstrated the existence of tower structures with different expression phenotypes and physical characteristics, suggesting that these towers exhibit different metabolic activities. Overall, the findings presented here support a model in which oxygen is important in the spatial and temporal control ofcidexpression within a biofilm and that tower structures formed during biofilm development exhibit metabolically distinct niches.

scholarly journals Novel Insights into Staphylococcus aureus Deep Bone Infections: the Involvement of Osteocytes

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Dongqing Yang ◽  
Asiri R. Wijenayaka ◽  
Lucian B. Solomon ◽  
Stephen M. Pederson ◽  
David M. Findlay ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Infection Model ◽  
Cell Type ◽  
Content Type ◽  
Intracellular Infection ◽  
Joint Replacement Surgery ◽  
Modes Of Failure ◽  
Common Pathogen ◽  
Small Colony

ABSTRACT Periprosthetic joint infection (PJI) is a potentially devastating complication of orthopedic joint replacement surgery. PJI with associated osteomyelitis is particularly problematic and difficult to cure. Whether viable osteocytes, the predominant cell type in mineralized bone tissue, have a role in these infections is not clear, although their involvement might contribute to the difficulty in detecting and clearing PJI. Here, using Staphylococcus aureus , the most common pathogen in PJI, we demonstrate intracellular infection of human-osteocyte-like cells in vitro and S. aureus adaptation by forming quasi-dormant small-colony variants (SCVs). Consistent patterns of host gene expression were observed between in vitro -infected osteocyte-like cultures, an ex vivo human bone infection model, and bone samples obtained from PJI patients. Finally, we confirm S. aureus infection of osteocytes in clinical cases of PJI. Our findings are consistent with osteocyte infection being a feature of human PJI and suggest that this cell type may provide a reservoir for silent or persistent infection. We suggest that elucidating the molecular/cellular mechanism(s) of osteocyte-bacterium interactions will contribute to better understanding of PJI and osteomyelitis, improved pathogen detection, and treatment. IMPORTANCE Periprosthetic joint infections (PJIs) are increasing and are recognized as one of the most common modes of failure of joint replacements. Osteomyelitis arising from PJI is challenging to treat and difficult to cure and increases patient mortality 5-fold. Staphylococcus aureus is the most common pathogen causing PJI. PJI can have subtle symptoms and lie dormant or go undiagnosed for many years, suggesting persistent bacterial infection. Osteocytes, the major bone cell type, reside in bony caves and tunnels, the lacuno-canalicular system. We report here that S. aureus can infect and reside in human osteocytes without causing cell death both experimentally and in bone samples from patients with PJI. We demonstrate that osteocytes respond to infection by the differential regulation of a large number of genes. S. aureus adapts during intracellular infection of osteocytes by adopting the quasi-dormant small-colony variant (SCV) lifestyle, which might contribute to persistent or silent infection. Our findings shed new light on the etiology of PJI and osteomyelitis in general.

Mineral composition and gemological characteristics of the fossil marine reptiles of the Ulyanovsk region

2018 ◽  
pp. 12-16 ◽  
Author(s):  
D. A. Petrochenkov
Keyword(s):  
Chemical Composition ◽  
Bone Tissue ◽  
Mineral Composition ◽  
Bone Structure ◽  
Upper Jurassic ◽  
Marine Reptiles ◽  
Ulyanovsk Region ◽  
Impurity Elements ◽  
Wide Assortment

Fossils of marine reptiles are a new jewelry and ornamental material and collected in the Ulyanovsk region from the Upper Jurassic deposits. They consist of (wt. %): calcite — 52, apatite — 24 and pyrite — 23, and also gypsum presents. The contents of radioactive and carcinogenic elements are close to background. The original bone structure of reptiles is preserved. Apatite replaces the bone tissue of marine reptiles, forming a cellular framework. According to the chemical composition, apatite refers to fluorohydroxyapatite with an increased Sr content. The size of the crystals is finely-dispersed. Calcite and pyrite fill the central parts of the cells. Calcite crystals of isometric and elongated shape, 0,01—0,05 mm in size, form blocks up to 0,3 mm during intergrowth. Calcite fills thin, discontinuous veins along the contour of cells with a width of up to 0,03 mm. In calcite, among the impurity elements, there are (wt. %, on the average): Mg — 0,30, Mn — 0,39 and Fe — 0,96. Pyrite forms a dispersed impregnation in calcite and apatite, content of impurities is, wt. %: Ni — up to 0,96 and Cu — up to 0,24. On technological and decorative characteristics of fossils of sea reptiles of Ulyanovsk region are qualitative jewelry and ornamental materials of biomineral group, allowing to make a wide assortment of jewelry and souvenir products.

Sign in / Sign up

Export Citation Format

Share Document