Pearl Oyster Shell Research Articles

Modification of Chitosan Isolation Method from Pearl Oyster Shell (Pinctada maxima sp) as A Source of Natural Polymer

Abstract Chitosan is natural polymer with abundant availability and unique characteristics. The purpose of this study was to investigate the effects of various isolation methods on chitosan properties. Chitosan was obtained by isolation method using oyster pearl shell (Pinctada maxima sp.). The parameters of the deacetylation process are the comparison of heating method with microwave method and the comparison of microwave power. Chitosan was characterized for degree of deacetylation (DD) and functional groups by FTIR, and viscosity by Brookfield viscometer. The microwave method was faster than the heating method. Then, the larger mass of shell and %NaOH produced a higher DD of 89.75%. However, the use of 60g mass and 60% NaOH resulted in an already high DD of 81.96%. Furthermore, variation microwave power showed the highest DD at high power. FTIR spectrum analysis showed the appearance of chitosan functional groups, OH and NH2 groups. The viscosity value decreased as the microwave power increased. Based on this study, different isolation methods affect the quality of chitosan. However, it’s necessary to conduct more detailed research related to changes in chemical structure. Therefore, oyster shells can produce chitosan as a source of natural polymers with different characteristics.

The effects of pearl oyster shell-derived bone grafts on TNF-alfa levels: An in vivo study in Cavia porcellus

Abstract Objective: This study aims to assess the effect of bone graft materials derived from pearl oyster shells on the tumor necrosis factor-alpha (TNF-α) level. Methods: This research utilized a bone graft containing hydroxyapatite Pinctada maxima (HPM) powder obtained from pearl oyster shells. Material testing was conducted on 30 male guinea pigs aged 8-10 weeks, divided into three groups: the negative control group, the group treated solely with HPM, and the group treated with HPM combined with platelet-rich fibrin (PRF). Each treatment group was observed for 7 and 14 days. The results were analyzed using One-way ANOVA with a significance level of p<0.05. Results: The findings demonstrated a decrease in the average TNF-α levels across all groups. On observation days 7 and 14, the HPM group exhibited a significant difference compared to the negative control group, indicating reduced TNF-α levels. However, no significant difference was observed when comparing the HPM group with the HPM and PRF groups. Conclusions: Bone grafts derived from pearl oyster shells possess high levels of hydroxyapatite, and the addition of PRF into the bone graft effectively reduces TNF-α.

Oral Administration of Nacre Extract from Pearl Oyster Shells Has Anti-Aging Effects on Skin and Muscle, and Extends the Lifespan in SAMP8 Mice.

Pearl oysters have been extensively utilized in pearl production; however, most pearl oyster shells are discarded as industrial waste. In a previous study, we demonstrated that the intraperitoneal administration of pearl oyster shell-derived nacre extract (NE) prevented d-galactose-induced brain and skin aging. In this study, we examined the anti-aging effects of orally administered NE in senescence-accelerated mice (SAMP8). Feeding SAMP8 mice NE prevented the development of aging-related characteristics, such as coarse and dull hair, which are commonly observed in aged mice. Additionally, the NE mitigated muscle aging in SAMP8 mice, such as a decline in grip strength. Histological analysis of skeletal muscle revealed that the NE suppressed the expression of aging markers, cyclin-dependent kinase inhibitor 2A (p16) and cyclin-dependent kinase inhibitor 1 (p21), and increased the expression of sirtuin1 and peroxisome proliferator-activated receptor gamma coactivator 1 (PGC1)- α, which are involved in muscle synthesis. These findings suggest that the oral administration of NE suppresses skeletal muscle aging. Moreover, NE administration suppressed skin aging, including a decline in water content. Interestingly, oral administration of NE significantly extended the lifespan of SAMP8 mice, suggesting that its effectiveness as an anti-aging agent of various tissues including skeletal muscle, skin, and adipose tissue.

Effect of nacre extract from pearl oyster shells against behavioral and psychological symptoms of dementia in senescence-accelerated mouse P8 (SAMP8)

Pearls have been used in traditional Chinese medicine for the treatment of myopia, epilepsy, and palpitations. We previously demonstrated that the intraperitoneal administration of nacre extract from pearl oyster shells prevents lipopolysaccharide-induced anxiety and depression-like behavior. In this study, nacre extract was orally administered to senescence-accelerated mice-prone 8 (SAMP8) mice at 125 ppm and 250 ppm for 26 weeks. Behavioral tests were performed at 28 weeks of age, followed by molecular analysis at 31 weeks. Administration of nacre extract suppressed anxiety and depressive behavior in SAMP8 mice. In addition, nacre extract ameliorated aggressive behavior and disruption of circadian rhythms in SAMP8 mice. Histological analysis showed that nacre extract prevented neurodegeneration in the hippocampus. RNA sequencing analysis of the brain revealed that nacre extract suppressed endoplasmic reticulum (ER) stress. In addition, nacre extract also suppressed increase in expression of inflammation-related proteins, such as tumor necrosis factor-alpha and interleukin-1. These results suggest that the oral administration of nacre extract suppresses behavioral alterations by suppressing ER stress and inflammation associated with aging in SAMP8 mice.

Casting light on formation of the pearl oyster shell with nanobeam X-ray total scattering

Casting light on formation of the pearl oyster shell with nanobeam X-ray total scattering

Red Seaweed Porphyra spp. (Bangiales) from Urimessing Waters of Ambon Island - Maluku

A study on the cultivation of Porphyra spp. has been carried out in the waters of Ambon Island. This plant is in great favor with local communities but has not been able to meet broader demands. The purpose of this research was to look into the future of mass culture. In the splashing zone, which is about 10 m above sea level, samples of gametophyte foliose or thalli were taken. The thallus was brought to the laboratory and maintained in a 100-liter container. During the rearing period, the thallus released spermatia and fertilized carpogonia. Carpogonia develop into carposporangia and release zygotospores outside the thallus. A small zygotospore develops into a large carpospore. Carpospores are the forerunners of new sporophytes if they find the correct substrate. In the laboratory, the nacre layer of pearl oyster shells was used to replace the natural substrates. Carpospores attached to the nacre layer germinated and grew into conchocelis. The conchocelis then develops the conchosporangia outward, followed by the release of the conchospores. Conchospores are a source of new thalli grown on polyethylene nylon nets. Conchospores that grew into new thalli on nylon nets were then moved to their natural environments so they could keep growing.

FABRICATION OF CHITOSAN BIOPOLYMER FROM PEARL OYSTER SHELLS (Pinctada maxima) FOR MEDICAL APPLICATIONS

Chitosan is one of the biopolymers that has recently been developed in the medical field. Chitosan is biocompatible, biodegradable, and non-toxic, so it is safe for the human body. This study aimed to identify the characteristics of chitosan isolated from pearl oyster shells. Chitosan is obtained through three stages: deproteination, demineralization, and deacetylation. Characterization of chitosan is done physically and chemically including organoleptic test, yield calculation in each step of isolation, FTIR, and XRD. Isolated chitosan identified deacetylation degree and functional group with FTIR. While the crystal structure was determined using XRD. The results showed that chitosan powder has a beige color with a final yield of 7,06%. The characterization of FTIR shows that synthesized pearl oyster shells have successfully formed chitosan compounds with a deacetylation degree of 81,50%. Another characteristic is the crystal structure obtained; chitosan has orthorhombic unit cells with a degree of chitosan crystallinity of 36,94%. Based on the result, chitosan has met several standards in medical applications as a biomaterial.

Nacre Extract from Pearl Oyster Shell Prevents D-Galactose-Induced Brain and Skin Aging.

Pearl oyster shells comprise two layers, a prismatic and nacreous layer, of calcium carbonate. The nacreous layer has been used in Chinese medicine since ancient times. In this study, we investigated the effects of the extract from the nacreous layer of pearl oysters (nacre extract) on D-galactose-induced brain and skin aging. Treatment with nacre extract led to the recovery of D-galactose-induced memory impairment, as examined using the Barnes maze, novel object recognition, and Y-maze tests. A histological study showed that nacre extract suppressed D-galactose-induced neuronal cell death and the expression of B cell lymphoma 2 (Bcl-2)-associated X protein (Bax), which causes apoptosis in the hippocampus. In addition, the expression levels of brain-derived neurotrophic factor, which counteracts age-related brain dysfunction, and nicotinamide adenine dinucleotide-dependent deacetylase (sirtuin 1), which delays aging and extends lifespan, increased after nacre extract treatment. Moreover, the nacre extract showed anti-aging effects against D-galactose-induced skin aging; it suppressed D-galactose-induced wrinkle formation, decreased skin moisture, decreased epidermal thickness, and destroyed collagen arrangement associated with aging. Furthermore, the nacre extract suppressed oxidative stress associated with aging in the brain and skin by upregulating the expression of catalase and superoxide dismutase. The expression level of the cellular senescence marker p16, which is induced by oxidative stress, was elevated in the hippocampus and skin epidermal layer of D-galactose-treated mice, and it was suppressed by the administration of nacre extract. These results show that the nacre extract can suppress D-galactose-induced aging by enhancing anti-oxidant activity and suppressing p16 expression. Thus, the nacre extract may be an effective anti-aging agent.

Shell colors and microstructures of four pearl oyster species in the South China Sea

Wild marine pearl oyster shells have rich colors, and the color and gloss of pearls cultivated by pearl oysters are closely related to the pearl layer color of the mantle. Therefore, in this study, four important wild marine pearl oyster species (Pinctada maxima, Pteria penguin, Pinctada margaritifera, and Pinctada fucata) were collected from the South China Sea, and a colorimeter was used to measure the color of their inner and outer shells. We analyzed the color range of their shells and the correlation between the color parameters; additionally, we observed the microstructure of their shells using a scanning electron microscope. The results showed that the color distribution and brightness of the inner shells of the four species were wider than that of the outer shells. In addition, the color distribution range of the outer and inner shells of the four pearl oyster species were P. fucata > P. margaritifera > P. maxima > Pt. penguin and Pt. penguin > P. fucata > P. margaritifera > P. maxima, respectively. Concerning the microstructures of the four pearl oysters, the shell structures of P. maxima, P. margaritifera and P. fucata had a honeycomb arrangement, whereas Pt. penguin had an irregular polygon structure. The P. maxima and P. margaritifera with a strong nacre secretion ability that area and thickness of the single crystal particles were larger than those of Pt. penguin and P. fucata.

Globular C1q domain-containing protein from Pinctada fucata martensii participates in the immune defense process

The globular C1q domain-containing (C1qDC) protein can recognize a variety of ligands, such as pathogen-associated molecular patterns, and plays an important role in the innate immune response. Our previous studies showed that a novel globular C1q domain-containing protein (PmC1qDC-1) is involved in the damage repair process of pearl oyster shells. However, the function of PmC1qDC-1 in pearl oyster innate immunity remains unknown. In the present study, the high-level structural analysis showed that PmC1qDC-1 was a spherical structure composed of 10 strands and was similar to the AiC1qDC-2 of bay scallop (Argopecten irradians). In situ hybridization indicated that PmC1qDC-1 had strong fluorescence signal in gills. Furthermore, the mRNA expression of PmC1qDC-1 was highly induced at 6–48 h in gill after lipopolysaccharide, peptidoglycan and polyinosinic–polycytidylic acid stimulation. Additionally, we obtained the recombinant protein of PmC1qDC-1 (rPmC1qDC-1) and found that rPmC1qDC-1 had antibacterial activity against Gram-negative (i.e., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Escherichia coli, and Aeromonas hydrophila) and Gram-positive (i.e., Staphylococcus aureus and Bacillus subtilis) bacteria. These results indicated that PmC1qDC-1 might play an important role in the immune response against bacteria and viruses. This study provides clues for further studying the immune defense of Pinctada fucata martensii against pathogens and exploring the evolution of the classic pathway of complement system.

Analysis of macro nutrient content in biofouling waste organic fertilizer pearl oyster (Pinctada maxima L.)

Biofouling development is a major problem in bilvave aquaculture around the world. The purpose of this study was to obtain macro nutrient analysis data for organic fertilizer from pearl oyster (Pinctada maxima L) biofouling waste. Where is the manufacture of solid organic fertilizer products that have quality equivalent to other commercial organic fertilizers by utilizing pearl oyster (Pinctada maxima L.) biofouling waste so that high quality solid organic fertilizers are produced which are in accordance with the Quality Standards for solid organic fertilizers and the Indonesian National Standard. Organic fertilizer from pearl oyster biofouling waste is obtained by using pearl oyster biofouling waste which is taken from the results of cleaning microorganisms attached to the pearl oyster shell area. Another major concern regarding biofouling is the potential for food competition caused by the attachment of the filter-feeder. Besides, the waste of biofouling pearl oysters is extracted and soaked in fresh water for one week at a time. Afterward, the pearl oyster biofouling waste is dried in the sun to dry, odorless, blackish brown in color. Analysis of macro nutrient content using Atomic Absorption Spectrophotometer and UV-Vis Spectrophotometer. The results of the analysis of macro nutrient content were Water Content (5.76%), C (14.48%), Organic Matter (24%), N-total (0.92%), P-total (0, 25%), K-total (1.02%), C/N ratio (15.72).

A shell matrix protein of Pinctada mazatlanica produces nacre platelets in vitro

Nacre is the main component of the pearl oyster shells and it is synthesized by specialized soluble and insoluble shell matrix proteins. Insoluble proteins from the decalcification of the shell are the less studied proteins due to the technical problems to isolate them from the organic matrix. In this study, an insoluble shell matrix protein from Pinctada mazatlanica, pearlin (Pmaz-pearlin), was successfully cloned from the mantle tissue, and the native protein isolated from the shell was functionally characterized. The full coding sequence of Pmaz-pearlin mRNA consists of 423 base pairs, which encode to a 16.3 kDa pearlin. Analysis of the deduced amino acid sequence revealed that Pmaz-pearlin contained four acidic regions, an NG repeat domain, and Cys conserved residues, the latter potentially forms four disulfide bridges which might stabilize the protein structure. The isolated protein from the shell is a glycoprotein of ~ 16.74 kDa which can produce aragonite and calcite crystals in vitro. Our results show that Pmaz-pearlin is a well-conserved protein involved in nacre layer growth, which produces calcite crystals in the presence of CaCl2, aragonite crystal polymorphs with a hexagonal structure in the presence of MgCl2, and needle-like crystal structure polymorphs in the presence of CaCO3 The identity of the crystals was confirmed using RAMAN analyses.

Esterification of Waste Cooking Oil using Heterogeneous Catalyst from Pearl Shell

Biodiesel is a renewable and environmentally friendly energy source. The process of using a homogeneous catalyst has several disadvantages, such as: removing a lot of waste water from washing the catalyst residue and cannot be reused. This catalyst is also low in corrosion and is more environmentally friendly. The purpose of this study was to study the preparation of heterogeneous catalysts from pearl shells applied to the cooking oil esterification reaction. The oil was then characterized by the XRD, XRF, SEM, and FTIR. The results of GCMS for reaction without catalysts yield only 27.07% by weight of alkyl ester, whereas using a catalyst is 93.4%. The influence of time, in the 60th minute, was the optimal time for the esterification reaction, and the effect of the weight of the catalyst which was 1% the optimal weight. This shows that pearl oyster shell catalyst can act as an esterification catalyst for used cooking oil and can be used as an alternative to a homogeneous catalyst substitute catalyst.

UNUSUAL ANIMAL RESOURCES EXPLAINED IN RASA RATNA SAMUCCHAYA

Rasa Ratna Samucchaya being an important treatise of Rasashastra from 12th Century A.D consists of var-ious references regarding the usage of diverse animal resources. Resources like various products and body parts by different animals are derived and are used for various purposes in different context. They were used for the purpose of Shodhana (purification), Marana (incineration), Satwapatana (process of extrac-tion of chief constituent of any mineral), Druti nirmana (liquid form of any metal/mineral) and in prepara-tion of different Mushas (crucibles) like Vajra musha, Vajra dravanimusha, Garamusha etc., as well as in the preparation of Rasayogas (formulations). They are also used as Anupana/Sahapana (adjuvants), Pathya and Apathya (diet and regimens to be followed and avoided). Not only animal resources but utiliza-tion of resources of birds, insects, worm as well as aquatic resources like Pravala (coral), Mukta (pearl), Shankha (conch shell), Muktashukti (pearl oyster shell), Agnijara (ambergies) etc., were also explained. In addition, usage of Nara mutra (human urine), Narasthi (human bone) and Nari sthanya (breast milk) are also mentioned. This article is an effort to compile and enlist about the assorted animal resources that has been told in Ayurveda Rasashastric text Rasa ratna samucchaya written by Rasa Vagbhata.

Overview of the Development and Modern Landscape of Marine Pearl Culture in the South Pacific

Natural marine pearls were a rare and valuable by-product of a fishery targeting pearl oyster shells for their mother-of-pearl (MOP). This fishery developed around the world throughout the 18th century and increased significantly through the 19th century in Australia and the Pacific islands. Overfishing of the MOP resource led to the development of pearl oyster spat (juvenile) collection techniques to assist stock replenishment. Although the MOP industry eventually ceased in the 20th century, spat collection provided a basis for pearl culture industries in the Pacific, that used nucleated pearl culture techniques developed in Japan. Today, French Polynesia is the largest producer of cultured round pearls in the South Pacific using the endemic black-lip pearl oyster Pinctada margaritifera. The successful French Polynesian pearl industry was a catalyst for development of pearl culture in other Pacific island countries such as the Cook Islands and Fiji. As well as significant export income, pearl culture offers livelihood opportunities (upstream and downstream) to coastal communities at a number of levels, including collection of pearl oyster spat (juveniles) for on-selling to pearl farms, and jewelry and MOP shell craft production. Despite being compatible with local lifestyles, round pearl culture has significant barriers to entry, including high initial investment, high operational costs, and requirement for a high level of technical skills. Alternatively, significant opportunities for coastal communities exist from production of mabé pearls (half pearls) because although not as valuable as high-grade round pearls, they are cheaper to produce, demand fewer technical skills, and pearls can be produced by local people with minimum training. Diversification of round pearl farms into mabé pearl production, or the establishment of stand-alone mabé pearl farms, is increasingly prevalent in Pacific pearl-producing nations, motivated by risk minimization, a broader market base, and a much simpler and less costly industry entry pathway.

Trivalent Iron Is Responsible for the Yellow Color Development in the Nacre of Akoya Pearl Oyster Shells.

The gold and cream colors of cultured Akoya pearls, as well as natural yellow nacre of pearl oyster shells, are thought to arise from intrinsic yellow pigments. While the isolation of the yellow pigments has been attempted using a large amount of gold pearls, the substance concerned is still unknown. We report here on the purification and characterization of yellow pigments from the nacre of Akoya pearl oyster shells. Two yellow components, YC1 and YC2, were isolated from the HCl-methanol (HCl-MeOH) extract from nacreous organic matrices obtained by decalcification of the shells with ethylenediaminetetraacetic acid (EDTA). Energy-dispersive X-ray and infrared spectroscopy analyses suggested that YC1 and YC2 precipitated under basic conditions are composed of Fe-containing inorganic and polyamide-containing organic compounds, respectively. YC1 solubilized under acidic conditions exhibited positive reactions to KSCN and K4[Fe(CN)6] reagents, showing the same ultraviolet-visible absorption spectrum as those of Fe(III)-containing compounds. In addition, X-ray absorption fine structure analysis supported the compound in the form of Fe(III). The total amount of Fe was approximately 2.6 times higher in the yellow than white nacre, and most Fe was fractionated into the EDTA-decalcifying and HCl-MeOH extracts. These results suggest that Fe(III) coordinated to EDTA-soluble and insoluble matrix compounds are mainly associated with yellow color development not only in the Akoya pearl oyster shells but also in the cultured Akoya pearls.

Control of biofouling on pearl oysters Pinctada imbricata using wax and Chinese herbs

Biofouling poses severe challenges to pearl oyster Pinctada imbricata culture in China, and controlling it is both labor- and capital-intensive. The antifouling properties of wax, and wax mixed with Chinese herbs, sprayed onto pearl oyster shell surfaces during peak biofouling seasons were evaluated. Pearl oysters coated with three wax treatments (plain wax, Chinaberry seed extract, Chinese honeylocust fruit extract) and a control (no treatment), were cultured in nets for up to 60 days. Mortality rate, fouling organism and pearl-oyster weights, and shell height are reported for individual oysters on each of six sampling dates. With the exception of oysters submerged for 12 days, all oysters were significantly affected by treatment type and submersion duration. Fouling weight increased more rapidly over time in the control-treatment oysters. Wax-based coatings deterred fouling-organism settlement on oysters for at least 2 months during the intensive fouling season, reducing mortality and not adversely effecting growth.

Pearl formation in the Japanese pearl oyster ( Pinctada fucata ) by CaCO 3 polymorphs: Pearl quality‐specific biomineralization processes and their similarity to shell regeneration

Pearl oyster shell consists of two layers: a calcite prismatic layer (outer layer) and an aragonite nacreous layer (inner layer). Calcite and aragonite are CaCO3 polymorphs, and their formations are controlled by shell-forming tissue called mantle. Pearl sacs originating in the mantle form cultured pearls. Therefore, it has been widely accepted that pearl and shell are produced by the same process. However, this idea has been called into question by some recent mineralogical studies indicating microstructural and crystal-polymorphic diversity in pearls. The pearl biomineralization process is still not fully understood in detail. Thus, in this study, we focused on the diversity of CaCO3 polymorphism of non-nacreous structures (NNSs) underlying the nacreous layer in pearl and regenerated shell, to reveal the biomineralization process of the Japanese pearl oyster (Pinctada fucata). Using Meigen's stain and scanning electron microscope-energy dispersive X-ray (SEM-EDX), NNSs polymorphs in valuable and valueless pearls, in addition to regenerated shell, were compared. Aragonite was exclusively observed in the NNSs of valuable pearls, whereas calcite was dominant in those of valueless pearls. The same analysis of NNSs of regenerated shells was carried out. As in valueless pearls, almost all regenerated shell NNSs consisted of calcite, but one NNS was composed of aragonite. Accordingly, it seems that pearls are formed by the same biomineralization process as shell regeneration rather than shell formation.

Breaking the long-standing morphological paradigm: Individual prisms in the pearl oyster shell grow perpendicular to the c-axis of calcite

Cross-sections of calcitic prismatic layers in mollusk shells, cut perpendicular to growth direction, reveal well-defined polygonal shapes of individual “grains” clearly visible by light and electron microscopy. For several kinds of shells, it was shown that the average number of edges in an individual prism approaches six during the growth process. Taking into account the rhombohedral symmetry of calcite, often presented in hexagonal axes, all this led to the long-standing opinion that calcitic prisms grow along the c-axis of calcite. In this paper, using X-ray diffraction and electron backscatter diffraction (EBSD), we unambiguously show that calcitic prisms in pearl oyster Pinctada margaritifera predominantly grow perpendicular to the c-axis. The obtained results imply that the hexagon-like habitus of growing crystallites may be not necessarily connected to calcite crystallography and, therefore, other factors should be taken into consideration. We analyze this phenomenon by comparing the organic contents in Pinctada margaritifera and Pinna nobilis shells, the later revealing regular growth of calcitic prisms along the c-axis.

Isolation and identification of an angiotensin I-converting enzyme inhibitory peptide from pearl oyster (Pinctada fucata) shell protein hydrolysate

Abstract Pearl oyster (Pinctada fucata) shell is a marine byproduct. In this study, we focused on the extraction of functional peptides from pearl oyster shell protein hydrolysate. Pearl oyster shell protein was hydrolyzed using two types of proteases, Nucleicin and Orientase 22 BF. The hydrolysate by Orientase 22 BF (6 h of reaction time) exhibited the highest angiotensin I-converting enzyme (ACE) inhibitory activity (82.4%, at peptide concentration of 0.25 mg/mL) with 26.0% degree of protein hydrolysis. The crude hydrolysate was extracted with water and fractionated into two segments (named F1 and F2) by gel chromatography on a Sephadex G-25 column. After consecutive purification of F1 through high-performance liquid chromatography (HPLC) on an ODS column twice, a hexapeptide with the sequence Gly-Val-Gly-Ser-Pro-Tyr (MW: 578.7 Da) was identified based on its amino acid sequence and through LC–MS. The final purified peptide exhibited 5.82 μg/ml of IC50 value of ACE inhibitory activity. Furthermore, Lineweaver-Burk plots suggested that the purified peptide acts as a competitive inhibitor against ACE. The results of this study suggest that pearl oyster shell proteins can be new attractive raw materials for the production of functional foods against hypertension.