scholarly journals Effect of the Elemental Content of Shells of the Bivalve Mollusks (Mytilus galloprovincialis) from Saldanha Bay (South Africa) on Their Crystallographic Texture

Biology ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1093
Author(s):  
Pavel Nekhoroshkov ◽  
Inga Zinicovscaia ◽  
Dmitry Nikolayev ◽  
Tatiana Lychagina ◽  
Alexey Pakhnevich ◽  
...  
Keyword(s):  
South Africa ◽  
Crystallographic Texture ◽  
Mytilus Galloprovincialis ◽  
Reference Model ◽  
Open Ocean ◽  
Elemental Content ◽  
Natural Conditions ◽  
Anthropogenic Inputs ◽  
Pole Figures ◽  
Mussel Shells

A both wild and farmed mussels in natural conditions, anthropogenic inputs are usually reflected in the increase of the content of specific elements. To determine the possible effect of the elemental patterns of farmed and wild mussels (Mytilus galloprovincialis) collected in the Saldanha Bay area (South Africa) on the crystallographic texture of the shells, the content of 20 elements in shells and 24 in the soft tissue of mussels was determined by neutron activation analysis. The crystallographic texture of mussel shells was analyzed using time-of-flight neutron diffraction. The wild mussels from open ocean site live in stressful natural conditions and contain higher amounts of the majority of determined elements in comparison with mussels farmed in closed water areas with anthropogenic loadings. The changes between the maximums of the same pole figures of the three samples are in the range of variability identified for the genus Mytilus. The content of Cl, Sr, and I was the highest in mussels from the open ocean site, which is reflected by the lowest mass/length ratio. The determined crystallographic textures of mussels are relatively stable as shown in the analyzed pole figures despite the concentrations of Na, Mg, Cl, Br, Sr, and I in shells, which significantly differ for wild and farmed mussels. The stability of the crystallographic texture that we observed suggests that it can be used as a reference model, where if a very different texture is determined, increased attention to the ecological situation should be paid.

scholarly journals Mussel Shells, a Valuable Calcium Resource for the Pharmaceutical Industry

Marine Drugs ◽  
2021 ◽  
Vol 20 (1) ◽  
pp. 25
Author(s):  
Magdalena Mititelu ◽  
Gabriela Stanciu ◽  
Doina Drăgănescu ◽  
Ana Corina Ioniță ◽  
Sorinel Marius Neacșu ◽  
...  
Keyword(s):  
Pharmaceutical Industry ◽  
Levulinic Acid ◽  
Mytilus Galloprovincialis ◽  
Pharmaceutical Preparations ◽  
Mussel Shell ◽  
Triticum Vulgare ◽  
Low Toxicity ◽  
Mussel Shells ◽  
Wheat Kernels ◽  
European Seas

(1) Background: The mussel (Mytilus edulis, Mytilus galloprovincialis) is the most widespread lamellibranch mollusk, being fished on all coasts of the European seas. Mussels are also widely grown in Japan, China, and Spain, especially for food purposes. This paper shows an original technique for mussel shell processing for preparation of calcium salts, such as calcium levulinate. This process involves synthesis of calcium levulinate by treatment of Mytilus galloprovincialis shells with levulinic acid. The advantage of mussel shell utilization results in more straightforward qualitative composition. Thus, the weight of the mineral component lies with calcium carbonate, which can be used for extraction of pharmaceutical preparations. (2) Methods: Shell powder was first deproteinized by calcination, then the mineral part was treated with levulinic acid. The problem of shells generally resulting from the industrialization of marine molluscs creates enough shortcomings, if one only mentions storage and handling. One of the solutions proposed by us is the capitalization of calcium from shells in the pharmaceutical industry. (3) Results: The toxicity of calcium levulinate synthesized from the mussel shells was evaluated by the method known in the scientific literature as the Constantinescu phytobiological method (using wheat kernels, Triticum vulgare Mill). Acute toxicity of calcium levulinate was evaluated; the experiments showed the low toxicity of calcium levulinate. (4) Conclusion: The experimental results highlighted calcium as the predominant element in the composition of mussel shells, which strengthens the argument of capitalizing the shells as an important natural source of calcium.

The relative importance of bladder versus neotenic stages of Polystoma marmorati and P. umthakathi in natural frog populations in South Africa

1998 ◽  
Vol 72 (2) ◽  
pp. 117-121 ◽  
Author(s):  
L.H. Du Preez ◽  
D.J. Kok
Keyword(s):  
South Africa ◽  
Significant Contribution ◽  
Relative Importance ◽  
Natural Conditions ◽  
High Prevalence ◽  
Low Prevalence ◽  
Very High

AbstractInfection levels of Polystoma marmorati (Polystomatidae: Monogenea) in the painted reed frog, Hyperolius marmoratus, and P. umthakathi in the kloof frog, Natalobatrachus bonebergi, were studied under natural conditions. The recorded prevalence for P. marmorati was generally high in adult frogs and low in tadpoles. In the case of P. umthakathi, the opposite was found with a low prevalence in adult frogs and a very high prevalence in tadpoles. Based on these findings, the hypothesis is presented that for P. marmorati the neotenic stage does not play a determining role and the population is maintained by bladder parasites. For P. umthakathi the neotenic stage appears to be more important than the bladder parasite and the population can probably survive without any significant contribution from bladder parasites.

scholarly journals Heavy Metals Assimilation by Native and Non-Native Aquatic Macrophyte Species: A Case Study of a River in the Eastern Cape Province of South Africa

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2676
Author(s):  
Getrude Tshithukhe ◽  
Samuel N. Motitsoe ◽  
Martin P. Hill
Keyword(s):  
Heavy Metals ◽  
South Africa ◽  
Sediment Quality ◽  
Point Sources ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Anthropogenic Inputs ◽  
Water And Sediment ◽  
Macrophyte Species ◽  
Water And Sediment Quality

There is continuous deterioration of freshwater systems globally due to excessive anthropogenic inputs, which severely affect important socio-economic and ecological services. We investigated the water and sediment quality at 10 sites along the severely modified Swartkops River system in the Eastern Cape Province of South Africa and then quantified the phytoremediation potential by native and non-native macrophyte species over a period of 6 months. We hypothesized that the presence of semi and permanent native and non-native macrophytes mats would reduce water and sediment contamination through assimilation downriver. Our results were variable and, thus, inconsistent with our hypotheses; there were no clear trends in water and sediment quality improvement along the Swartkops River. Although variable, the free-floating non-native macrophyte, Pontederia (=Eichhornia) crassipes recorded the highest assimilation potential of heavy metals in water (e.g., Fe and Cu) and sediments (e.g., Fe and Zn), followed by a submerged native macrophyte, Stuckenia pectinatus, and three native emergent species, Typha capensis, Cyperus sexangularis, and Phragmites australis. Pollution indices clearly showed the promising assimilation by native and non-native macrophytes species; however, the Swartkops River was heavily influenced by multiple non-point sources along the system, compromising the assimilation effect. Furthermore, we emphasise that excessive anthropogenic inputs compromise the system’s ability to assimilate heavy metals inputs leading to water quality deterioration.

scholarly journals Levels of Elements in Typical Mussels from the Southern Coast of Africa (Namibia, South Africa, Mozambique): Safety Aspect

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3238
Author(s):  
Pavel Nekhoroshkov ◽  
Jacques Bezuidenhout ◽  
Inga Zinicovscaia ◽  
Nikita Yushin ◽  
Konstantin Vergel ◽  
...  
Keyword(s):  
South Africa ◽  
Food Source ◽  
Mytilus Galloprovincialis ◽  
Soft Tissues ◽  
Hazard Indices ◽  
The West ◽  
Calculated Risk ◽  
Permissible Levels ◽  
Main Food Source ◽  
Richards Bay

The soft tissues of mussels are often used as the main food source, especially in coastal areas. Neutron Activation Analysis was used to measure the content of 24 macro- and microelements in the soft tissues and 18 elements in the shells of selected sets of mussels of the species Mytilus galloprovincialis. The mussels were collected in 8 polluted and 4 pristine zones, which included Namibia, the west and east coasts of South Africa, and Mozambique. According to factor analysis Co, Ni, Zn, As, Se, Br, I, Sb could have anthropogenic origin. The concentrations of elements such as Cr, As, Se and partly Zn at polluted stations were above the maximum permissible levels for seafood. The concentrations of Sc, V, Cr, Mn, Co, Ni, Sb, Cs, Th, U in shells and soft tissues of the same mussels were at the close levels. Elements such as Al, Cr, Co, As (partly Zn, Se, and I) are considered to be harmful to human health at the levels of mussels consumption of 200 g/week per person and lower in such zones as Swakopmund, East London, Port Shepstone, Richards Bay, Xai-Xai according to calculated risk quotients and target hazard indices.

Baseline levels of antioxidant activities in Mytilus galloprovincialis along the coast of Cape Town, South Africa

2019 ◽  
Vol 140 ◽  
pp. 287-293 ◽  
Author(s):  
Conrad Sparks ◽  
Jeanine Marnewick ◽  
Rashieda Toefy ◽  
Reinette Snyman ◽  
James Odendaal
Keyword(s):  
South Africa ◽  
Mytilus Galloprovincialis ◽  
Antioxidant Activities ◽  
Cape Town ◽  
Baseline Levels

scholarly journals Impact of rolling conditions on the hydriding of grade 2 titanium welded tubes

2020 ◽  
Vol 321 ◽  
pp. 09005
Author(s):  
La Chance LEPEMANGOYE ◽  
Nicolas CRETON ◽  
Virgil OPTASANU ◽  
Elise DELOYE ◽  
Tony MONTESIN ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Crystallographic Texture ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
Asymmetrical Rolling ◽  
Commercially Pure ◽  
Pole Figures ◽  
Cold Rolled ◽  
Titanium Grade ◽  
The Impact

In this article, we study the impact of rolling conditions on the texture of the commercially pure titanium grade 2. In a previous work, NEOTISS in collaboration with ICB laboratory, shown that the texture highly influences the precipitation of hydrides in Titanium. In order to create different textures, Titanium sheets grade 2 are cold rolled asymmetrically and symmetrically with or without lubricant. The inverse pole figures and direct pole figures obtained allow us to deduce that symmetrical cold rolling does not change the grains orientation but generates a rotation of grains along c-axis (normal to basal plan). However, asymmetrical cold rolling leads to the formation of a new crystallographic texture, which could limit the formation of the hydrides in titanium grade 2 submitted to a hydrogen-rich environment. Key words: asymmetrical rolling, symmetrical rolling, titanium, hydriding, texture

Oxygen and carbon stable isotopes of Mytilus galloprovincialis Lamarck, 1819 shells as environmental and provenance proxies

The Holocene ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 65-76 ◽  
Author(s):  
Stefania Milano ◽  
Bernd R Schöne ◽  
Igor Gutiérrez-Zugasti
Keyword(s):  
Stable Isotopes ◽  
Mytilus Galloprovincialis ◽  
Shell Growth ◽  
Geochemical Data ◽  
Carbon Stable Isotopes ◽  
Northern Spain ◽  
Mollusc Shell ◽  
Geochemical Composition ◽  
Mussel Shells ◽  
Geochemical Analyses

Mollusc shell stable isotopes are commonly used to reconstruct past environmental conditions. However, despite being abundant components of natural and anthropogenic fossil accumulations, the geochemical composition of mussel shells ( Mytilus spp.) has rarely received attention in palaeoenvironmental studies. This study tests the suitability of oxygen isotopes (δ18Os) of Mytilus galloprovincialis as palaeothermometer. For 1 year, mussels and water samples were collected twice a month from Berria Beach, in Northern Spain. The geochemical data of the shells indicate that water temperatures can be reconstructed with an average offset of 1.2 ± 0.7°C with respect to the measured values. Furthermore, no prolonged shell growth cessations are observed. These results validate M. galloprovincialis as reliable recorders of seasonal water temperature fluctuations, supporting their use in palaeoenvironmental studies. In addition, further shell and water collections were carried out in the upper and lower areas of a nearby estuary. The geochemical analyses of these shells were aimed to test whether oxygen and carbon stable isotopes (δ13Cs) may be used as novel proxies to identify the shell provenance at local scale. The results show that the δ18Os versus δ13Cs correlation direction varies along the coast–upper estuary geographical gradient, suggesting it to be a potential new proxy to distinguish between marine and estuarine mussel specimens.

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