Ultrastructural evidence of four types of lipofuscins in the melanomacrophagic centers in hepatocytes of zebrafish (Denio rerio).

Melanomacrophagic centers (MMCs) were studied in the hepatocytes of zebrafish using transmission electron microscope (TEM). The MMCs with irregular or amoeboid nucleus were located in the hepatocytes adjacent to the bile canaliculi. Several engulfed structures were present in the cytoplasm of MMCs. The most frequent observation was the presence of mitochondria, ranging in size from small to giant, with distorted shape and inconspicuous cristae. Occasionally the fragments of erythrocytes were found. The rough endoplasmic reticulum (rER) showed whirling around the mitochondria and lipid droplets, forming membrane-like structures. The damaged mitochondria were invaded by the lysosomes, and this was covered by a membrane led to the formation of lipofuscin. Four different types of lipofuscins were observed; namely, (1) granular with/without vacuoles of high electron-density, (2) homogenous surrounded by indistinct limiting membrane, (3) lamellated structures similar to inner matrix and cristae of mitochondria, and, (4) compound structure made by the combinations of first 3 types, (granular and homogenous, granular and lamellated, homogenous and lamellated). The present evidence suggests that MMCs in the hepatocytes of zebrafish perform continuous functions of removal of the damaged cellular organelles. The lipofuscin formation work in coordination with the cellular players of immune system and remove pathogens and maintain the internal homeostasis of cells.

Identification of Telocytes in the Pancreas of Turtles-A role in Cellular Communication.

The existence of telocytes (TCs) has not yet been established in the pancreases of aquatic reptiles. Here, we report TCs in the exocrine pancreas of Pelodiscus sinensis using transmission electron microscope (TEM), immunohistochemistry (IHC), and immunofluorescence (IF) techniques. TCs surrounded the acini and ducts of the connective tissue of the exocrine pancreas and between lobules and gland cells. The cells were located preferably close to the blood vessels, interlobular ducts, and nerve fibers. Ultrastructurally, TCs exhibited small and large bodies with thick and thin portions, podoms, and podomers, and prolongations that form dichotomous branching with hetero-cellular and homo-cellular junctions. The podom (thick) portions showed caveolae, mitochondria, rough endoplasmic reticulum, and vesicles. The nucleus carries heterochromatin and is irregular in shape. The shape of TCs depends on the number of telopodes (Tps) bearing long, short, spindle, triangular, and "beads on a string" shapes with twisted, tortuous prolongations and ramifications. Shed extracellular vesicles and exosomes were found frequently released from projections and Tps within connective tissue in the vicinity of the acini and collagen fibers. IHC and IF results showed CD34+, α-SMA+, and vimentin+, long and triangle-shaped TCs, consistent with the TEM findings. The presence of shaded vesicles from TCs might implicate their possible role in immune surveillance, tissue regeneration as well as regulatory functions in the reptilian pancreas.

A critical review on male-female reproductive and developmental toxicity induced by micro-plastics and nano-plastics through different signaling pathways.

It is widely accepted that humans are constantly exposed to micro-plastics and nano-plastics through various routes, including inhalation of airborne particles, exposure to dust, and consumption of food and water. It is estimated that humans may consume thousand to millions of micro-plastic particles, equating to several milligrams per day. Prolonged exposure to micro-plastics and nano-plastics has been linked to negative effects on different living organisms, including neurotoxicity, gastrointestinal toxicity, nephrotoxicity, and hepatotoxicity, and developmental toxicities. The main purpose of this review is to explore the effect of micro-plastics and nano-plastics on the male and female reproductive system, as well as their offspring, and the associated mechanism implicated in the reproductive and developmental toxicities. Micro-plastics and nano-plastics have been shown to exert negative effects on the reproductive system of both male and female mammals and aquatic animals, including developmental impacts on gonads, gametes, embryo, and their subsequent generation. In addition, micro-plastics and nano-plastics impact the hypothalamic-pituitary axes, leading to oxidative stress, reproductive toxicity, neurotoxicity, cytotoxicity, developmental abnormalities, poor sperm quality, diminishes ovarian ovulation and immune toxicity. This study discusses the so many different signaling pathways associated in the male and female reproductive and developmental toxicity induced by micro-plastics and nano-plastics.

Effect of Selenium Nanoparticles and Chitosan on Production Performance and Antioxidant Integrity of Heat-Stressed Broiler.

In this study, 336-day-old corn cob broilers were bought for the poultry experimental station during the months of May and June 2021. Before the arrival of chicks, the brooders, chick feeders, drinkers, humidity, temperature, and feeding management were controlled according to scientific patterns. These birds were randomly divided into seven groups and six replications of eight birds, viz. Group-A (positive control on basal diet only), Group-B (negative control on basal diet and HS), group-C (basal diet + simple Se 0.3 mg/kg feed), Group-D (basal diet + SeNP 0.3 mg/kg feed + HS), Group-E (BD + HS + chitosan), Group-F (BD + Se + COS), and Group-G (nano Se with chitosan 0.3 mg/kg + BD + HS). On the 42nd day of research, two birds were selected from each replication and sacrificed after blood collection. The initial data related to feeding intake, live body weight, and feed conversion ratio (FCR) were collected before slaughter. The intestinal samples were collected and immediately transferred to formalin after grass morphometry. The live body weight, FCR, feed intake, intestinal histomorphology, relative organ weight, and antioxidant parameters like MDA, SOD, and GPX were significant (P > 0.005) in all groups, with Group-G at the highest, followed by Groups-F, E, D, C, A, and B. Group-B (negative control group) was the most affected group in all aspects because of heat stress and only basal diet. It was concluded that heat stress highly causes a loss in performance, intestinal gross morphology, and histology in poultry, and increases stress conditions, whereas the selenium nanoparticle works to improve the body weight, FCR, and intestinal parameters.

Cross-Talk Between Selenium Nanoparticles and Cancer Treatment Through Autophagy.

Autophagy is commonly referred as self-eating and a complex cellular process that is involved in the digestion of protein and damaged organelles through a lysosome-dependent mechanism, and this mechanism is essential for maintaining proper cellular homeostasis. Selenium is a vital trace element that plays essential functions in antioxidant defense, redox state control, and range of particular metabolic processes. Selenium nanoparticles have become known as a promising agent for biomedical use, because of their high bioavailability, low toxicity, and degradability. However, and in recent years, they have attracted the interest of researchers in developing anticancer nano-drugs. Selenium nanoparticles can be used as a potential therapeutic agent or in combination with other agents to act as carriers for the development of new treatments. More intriguingly, selenium nanoparticles have been extensively shown to impact autophagy signaling, allowing selenium nanoparticles to be used as possible cancer treatment agents. This review explored the connections between selenium and autophagy, followed by developments and current advances of selenium nanoparticles for autophagy control in various clinical circumstances. Furthermore, this study examined the functions and possible processes of selenium nanoparticles in autophagy regulation, which may help us understand how selenium nanoparticles regulate autophagy for the potential cancer treatment.

Ultrastructural Evidence of Melanomacrophagic Centers and Lipofuscin in the Liver of Zebrafish (Denio rerio).

Melanomacrophagic centers (MMCs) were studied in the liver of zebrafish using transmission electron microscope (TEM). The MMCs were located in the space of Disse (SD), and their pseudopodia protruded into the lumen of sinusoids. The degree of extension of body structure of MMCs in the SD was determined by the size of the phagocytosed content. An irregular or amoeboid nucleus was present. Vacuoles were occasionally present, both, in endothelium and MMCs. The cytoplasm of MMCs showed several engulfed structures. The most common structure was the presence of mitochondria of small to giant size and distorted shape with inconspicuous cristae. The product of mitochondrial degeneration accompanied by lysosomes contributed to the formation of lipofuscins. Besides, changes were also observed in rough endoplasmic reticulum (rER), the Golgi complex, and lysosomes. Occasionally, small to large fragments of the erythrocytes were found in the cytoplasm of MMCs. The rER encompassed the mitochondria and lipid droplets forming a membrane-like structure. Golgi complex were dilated. Lysosomes fused with such membrane-bound structures contributed to the formation of the lipofuscin. The results provide evidence of the role of liver-resident MMCs of zebrafish in phagocytosis of damaged organelles, clearance of the worn-out erythrocytes, and lipofuscin formation.

Novel cellular evidence of lipophagy within the Sertoli cells during spermatogenesis in the turtle.

Spermatogenesis is a complex process producing haploid spermatozoa, and the formation of lipid droplets (LDs) within Sertoli cells is critical to maintaining normal spermatogenesis. However, the utilization of LDs within Sertoli cells is still largely unknown. In the present study, proliferation of spermatogonial cells had begun in May, whereas the meiotic cells occurred predominately in July and majority of spermiogenic cells were observed in the seminiferous tubules in October. However, TEM and Oil Red O staining demonstrated that a larger number of LDs had accumulated within the Sertoli cells in May compared to that in October. There were several LDs attached to the isolation membrane/phagophore, suggesting that the LDs may be a source of endogenous energy for the biogenesis of autophagosomes. The LDs were enclosed within the autophagosomes in May, whereas, autophagosomes and mitochondria were directly attached with large LDs within the Sertoli cells in October. Furthermore, immunohistochemistry results demonstrated the stronger localization of LC3 on the Sertoli cells in May than in October. This study is the first to provide clear evidence of the two different modes of lipophagy for lipid consumption within Sertoli cells, which is a key aspect of Sertoli germ cell communication during spermatogenesis.

The ultrastructural characteristics of the spermatozoa stored in the cauda epididymidis in Chinese soft-shelled turtle Pelodiscus sinensis during the breeding season.

The ultrastructure of spermatozoa in cauda epididymidis of soft-shelled turtle, P. sinensis during breeding season was investigated by light microscopy (LM) and electron microscopy (TEM and SEM). The mature spermatozoa appeared elongated and filiform. In general, the turtle spermatozoon contains a characteristic head, midpiece and tail, similar in morphology to that of birds, amphibians and other reptiles. However, several features are unique. These include (1) three intranuclear tubules containing dense core extend from the subacrosomal cone through the rostral nucleus and deep into the nuclear body; (2) the midpiece is composed of 40 mitochondria which present a staggered rings-and-columns arrangement (8 parallel rings and 5 columns); (3) unusual spherical mitochondria with a dense core are surrounded by 8-10 concentric layers of cristae. Surprisingly, about 21.4±3.6 percent immature spermatozoa with normal morphology are also observed in this season. Different from the mature spermatozoa, a variable amount of cytoplasm droplets are attached to the immature spermatozoa under SEM. Some spermatozoa still show the tail coiled tightly around the cytoplasm. These spermatozoa in transverse sections under TEM, showed a large amount of cytoplasm wrapped by plasma membrane; even some free mitochondria and higher electron density material still seen in the cytoplasm. Among the immature spermatozoa, most of them possess a cytoplasmic droplet which is located eccentrically on the midpiece, and contains a lot of lipid droplets in addition to hollow vesicles. Lipid droplets are closely associated with mitochondrial membranes and may function in the formation or degradation of mitochondria. These immature spermatozoa may be the dormant cells, but whether or not they can fertilize the ovum or not is unknown. Thus, in the present study we hypothesized that the cauda epididymidis might be involved in the sperm maturation in this species.

Quantitative changes of nitrergic neurons during postnatal development of chicken myenteric plexus.

OBJECTIVE: Information regarding the development of the enteric nervous system (ENS) is important for understanding the functional abnormalities of the gut. Because fertilized chicken eggs provide easy access to embryos, chicken models have been widely used to study embryonic development of myenteric plexus; however, no study has been focused on the postnatal period. The aim of this study was to perform a qualitative and quantitative analysis of the nitrergic neurons in the myenteric plexus of developing chickens in the postnatal period. METHODS: Whole-mount preparations of the myenteric plexus were made in 7-d, 15-d, and 40-d old (adult) chickens of either sex (n=15). The myenteric plexus was studied after nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry using light microscopy, digital photography, and Image-Pro Plus 6.0 software. The numbers of positively stained neurons and ganglia were counted in the duodenum, jejunum, ileum, caecum, and colon in the different age groups. Data were expressed as mean±standard deviation (SD), and statistical analysis was performed using a one-way analysis of variance (ANOVA) test. RESULTS: The positively stained neurons showed various morphologies and staining intensities, and formed bead-shaped and U-shaped arrangements in the myenteric plexus. The densities of neurons and ganglia increased with age. However, the number of positive neurons per ganglion increased. The number of NADPH-d-positive neurons was highest in the colon, followed by the ileum, the jejunum, the duodenum, and the caeca in all age groups. CONCLUSIONS: Developmental changes in the myenteric plexus of chickens continue in the postnatal period, indicating that the maturation process of the gastrointestinal function is gradual. In addition, no significant difference is happening among different intestinal segments during postnatal development, suggesting that the function of different intestinal segments had been determined after birth.

Micro-ultrastructure features of liver in Chinese Taihe black-bone silky fowl (Gallus gallus domesticus Brisson) / Características ultraestructurales de hígado en la gallina silky China Taihe de hueso negro (Gallus gallus domesticus Brisson)

In this work, the morphological features of liver in Chinese Taihe black-bone silky Fowl (BSF) were analyzed by light microscope and transmission electron microscopy. The results showed that two kinds of hepatocytes were present in Taihe BSF liver, i.e., the dark and the light hepatocyte. The dark hepatocyte was electron-dense and lager, with many organelles, mitochondria especially. The light hepatocytes were smaller than the dark. They had electron-lucent cytoplasm with a small number of organelles. Furthermore, there were lipolysosomes in the light hepatocyte. The numerous long and serried finger-like microvilli spread into bile canaliculus lumen. The glycogen granules intensely stained, spread in some hepatocytes. Numerous glycogen granules scattered in cytoplasm especially near bile canaliculi. However, lipid droplets were not observed in any hepatocytes. The natural apoptotic hepatocytes were observed in Taihe BSF liver. The hepatocytes which contain abundant uesicae-like endoplasmic reticulum closed the apoptotic hepatocytes and spread the process to approach the cell residual bodies. Besides, there was a macrophage with several phagosomes. In conclusion, the dark and the light hepatocyte were present in Chinese Taihe BSF liver. They were different from electron-dense and organelles. The hepatocytes of Taihe BSF could undergo natural apoptosis, regeneration and renew ability.

Fueron analizadas las características morfológicas ultraestructurales de hígado en la gallina sedosa china de hueso negro por microscopía óptica y microscopía electrónica de transmisión. Los resultados mostraron que se encontraron hepatocitos claros y oscuros en el hígado de la gallina china Taihe. El hepatocito oscuro era denso y de mayor tamaño. Tenía numerosos organelos, especialmente mitocondrias. Los hepatocitos claros eran más pequeños que los oscuros. El citoplasma presentó un pequeño número de organelos. Además, había lipolisosomas en los hepatocitos claros. Numerosas microvellosidades se extendían hacia los canalículos biliares. En algunos hepatocitos se observó una tinción marcada en los gránulos de glucógeno. Sin embargo, no se observaron gotas de lípidos en los hepatocitos. Se observaron los hepatocitos apoptóticos naturales en el hígado de la gallina Silky Taihe. Aquellos hepatocitos que contenían abundante retículo endoplásmico, cerraban los hepatocitos apoptóticos y extendían el proceso de acercamiento a cuerpos residuales celulares. También hubo un macrófago con varios fagosomas. En conclusión, los hepatocitos claros y oscuros estaban presentes en el hígado de la gallina Taihe china. Estos diferían de electrones de alta densidad y organelos. Los hepatocitos de la gallina Taihe presentaron una apoptosis natural y capacidad de regeneración.