Screening of Auricularia auricula strains for strong production ability of melanin pigments

Abstract Melanin pigments have great application value and development potential in food industry to use as nature functional food colorants. In initial study, twenty-two Auricularia auricula strains were screened for stronger production ability of melanin pigments by solid culture. Three A. auricula strains (RF201, QD2 and QD6) with higher pigment production capacity were selected for further study through submerged culture supplementing 1 g/L l-tyrosine. The maximal pigment yields of A. auricula RF201, QD2 and QD6 were 493.9, 367.6 and 318.5 mg/L, respectively. Among three strains, A. auricula RF201 possessed the strongest production ability of melanin pigments. The present study indicated that A. auricula RF201 could be used as potential excellent producer of melanin pigments.

The histology of the pineal gland in cadaveric embalmed specimens.

Objective: This study is to observe ultrastructurally of the pineal gland from cadaveric embalmed specimens by light microscopy (LM) and transmission electron microscopy (TEM) Methods: Ten pineal glands were removed from cadaveric embalmed specimens. Each pineal gland was disected into two groups, one was put into 10% formaldehyde and the other was put into 2.5% glutaraldehyde. The first group was processed for light microscopy. First of all, fixed the tissues in formalin and then embedded in paraffin. Next, serially sectioned at eight micron and finally stained. Staining methods were (i) haematoxylin and eosin, (ii) Masson-Fontana method for melanin. The second group well preserved in 2.5% glutaraldehyde was chosen to prepare for the TEM. Results: Only five out of ten cadaveric pineal glands viewed by light microscopy were well preserved. In LM, we saw clearly that all ultrastructures or morphology of the cadaveric embalmed pineal gland cells were the same as the standard textbook. Melanin pigments were accumulated in both of the cytoplasm of pinealocytes and the stroma of pineal gland proved by Masson-Fontana staining. Mast cells were found throughout the gland but preferably found in the connective tissue trabeculae. A neuronal-like cell was found in the parenchyma of pineal gland. Extrapineal and intrapineal calcified concretion called corpora arenacea or brain sand were presented. Intrapineal concretions in the parenchyma were globular and concentric lamellar patterns while extrapineal concretions which were adjacent to the capsule were concentric lamellar only. TEM of pineal gland showed that it was moderately preserved in the chemical fixative of this formula. Cadaveric pinealocyte showed some organelles and chromatin extraction while the environmental fibrillar structures were well preserved. Conclusion: The histological findings in the pineal glands from cadaveric embalmed specimens are similar to fresh cadavers. Moreover, they can be used to prepare the normal slides for Histology Lab of the second year medical students. The presences of the melanin pigments in the cytoplasm of pinealocytes and stroma, mast cells, corpora arenacea, and neuronal-like cells confirm the previous studies.