Twenty-four adult molly fish (Poecilia sphenops, Valenciennes 1846) were collected to study
the morphology and distribution of ganglia using histological, immunohistochemical, and electron
microscopy and focusing on their relation to the immune cells. The ganglia were classified spatially
into cranial and spinal, and functionally into sensory and autonomic. Spinal ganglia (dorsal root
ganglia, DRG) contained large close ganglionic cells, enclosed by satellite cells, as well as bundles of
both myelinated and non-myelinated nerve fibers. There are glial cells, immune cells and telocytes
close to the ganglion. In addition, oligodendrocytes were closely related to myelinated axons. Glial
fibrillary acidic protein (GFAP) expression was confined to the glia cells and the nerve fibers in
the cervical ganglia next to the gills, and surprisingly, in the large ganglionic cells of the DRG. The
vestibular ganglia were large, connected to the hind brain, and contained numerous neurons packed
in columns. The cervical ganglia were large and observed around the pseudobranch, head kidney,
and thymus. Their neurons are randomly distributed, and nerve fibers are peripherally situated.
CD3-positive T-lymphocytes, dendritic cells, and CD68-positive macrophages were in close contact
with the ganglia. Furthermore, the ganglia around the head kidney showed positive Iba1-expressing
cells. Most ganglion cells and nerve fibers in the DRG, autonomic, and vestibular ganglia showed
moderate to strong S-100 immunoreactivity. The enteric glia, CD68-expressing macrophages, and
acetylcholine (Ach)-expressing neurons were observed along the muscular layer of the intestinal wall.
In conclusion, different ganglia of molly fish displayed direct communication with immune cells
which support and maintain healthy ganglionic cells.

This study identified the cellular compositions of the gills in molly fish and their role
in immunity using light-, electron- microscopy, and immunohistochemistry. The molly fish gills
consisted of four holobranchs spaced between five branchial slits. Each hemibranch carried many
fine primary and secondary gill lamellae. The gill arch was a curved cartilaginous structure, from
which radiated the bony supports of the primary lamellae. The gill arch contained the afferent and
efferent brachial arteries. The gill arch was covered by epidermal tissue rich with mucous cells. The
primary lamella had a central cartilaginous support and efferent and afferent arterioles and was
covered with pavement cells (PVC), salt-secreting chloride cells, and pale-staining mucous cells.
These chloride cells contained abundant mitochondria and tubulovesicular system and are involved
in ionic transport with a potential role in detoxification. The surface of the secondary lamellae (site of
gaseous exchange) consisted of overlapping or interdigitating PVC supported and separated by pillar
cells. Other cells were found within the gill epithelium and interstitial connective tissues, including
lymphocytes, macrophages, monocytes, telocytes, stem cells, astrocytes, and neuroepithelial cells.
The immunohistochemical analysis revealed that APG-5, iNOS-2, IL-1, NF-B, and TGF-B showed
positive immunoreactivity in macrophages. The epithelium of the primary gill lamellae contained
positive-GFAP astrocytes and S100 protein—chloride cells. The stem cells expressed SOX9, myostatin,
and Nrf2. Neuroendocrine cells expressed S100 protein. In conclusion, the current work suggests
that the gills of molly fish are multifunctional organs and are involved in immune reactions.

The liver of fish is considered an ideal model for studying the collaboration between environmental agents and the
health state of the fish, where it gives good indications about aquatic ecosystem status. Therefore, this study presented
immune roles for the liver in molly fish (Poecilia sphenops), using immunohistochemistry and transmission
electron microscopy (TEM). The hepatocytes’ sinusoidal structures of molly fish livers had taken two different forms;
cord-like and tubular, while the biliary tract system showed two different types: isolated and biliary venous tract. The
TEM showed that the hepatocytes possessed well-developed cytoplasmic organelles and numerous glycogen and
lipid droplets of different sizes. Kupffer cells, Ito cells, aggregation of intrahepatic macrophages and melanomacrophages
were also recognized. Melanomacrophages contained numerous phagosomes, many lysosomes, cytoplasmic
vacuoles, and melanin pigments. Hepatocytes and Kupffer cells expressed immunoreactivity to APG5, indicating
that these cells were involved in the process of autophagy. Telocytes (TCs) were also recognized in the liver of molly
fish, and they shared the same morphological characteristics as those in mammals. However, TCs expressed strong
immunoreactivity to APG5, TGF-β, and Nrf2, suggesting their possible role in cellular differentiation and regeneration,
in addition to phagocytosis and autophagy. Both IL-1β and NF-KB showed immunoreactivity in the hepatocytes and
in inflammatory cells (including intrahepatic macrophages and melanomacrophage center). Nrf2 and SOX9 showed
immunoreactivity in hepatocytes, stem cells, and macrophages. The present study showed the spatial distribution of
hepatic vascular-biliary tracts in molly fish. The liver of molly fish has unique functions in phagocytosis, autophagy,
and cell regeneration. The expression of APG5 in hepatocytes, Kupffer cells, melanomacrophages, and telocytes supports
the role of the liver in lymphocyte development and proliferation. The expression of TGF-β and NF-κB in hepatocytes,
Kupffer cells, telocytes, and macrophages suggests the role of the liver in regulation of cell proliferation and
immune response suppression. The expression of IL-1β and Sox9 in macrophages and melanomacrophages suggests
the role of the liver in regulation of both innate and adaptive immunity, cell proliferation and apoptosis, in addition to
stem cell maintenance.

The pseudobranch is a gill-like structure that exhibits great variations in structure and function
among fish species, and therefore, it has remained a topic of investigation for a long time. This
study was conducted on adult Molly fish (Poecilia sphenops) to investigate the potential functions of
their pseudobranch using histological, histochemical, immunohistochemical analysis, and scanning
electron microscopy. The pseudobranch of Molly fish was of embedded type. It comprised many rows
of parallel lamellae that were fused completely throughout their length by a thin connective tissue.
These lamellae consisted of a central blood capillary, surrounded by large secretory pseudobranch
cells (PSCs). Immunohistochemical analysis revealed the expression of PSCs for CD3, CD45,
iNOS-2, and NF-κB, confirming their role in immunity. Furthermore, T-lymphocytes-positive CD3,
leucocytes-positive CD45, and dendritic cells-positive CD-8 and macrophage- positive APG-5 could
be distinguished. Moreover, myogenin and TGF-β-positive PSCs were identified, in addition to nests
of stem cells- positive SOX-9 were detected. Melanocytes, telocytes, and GFAP-positive astrocytes
were also demonstrated. Scanning electron microscopy revealed that the PSCs were covered by
microridges, which may increase the surface area for ionic exchange. In conclusion, pseudobranch
is a highly specialized structure that may be involved in immune response, ion transport, acid–base
balance, as well as cell proliferation and regeneration.

Recently, teleost species have been considered important model systems for investigating
different research areas including immunologic one. The available literature
provides poor data about the localization and the structure of pancreas in Molly fish.
Moreover, little attention has been paid to the immunologic role of pancreatic tissue
of teleost, particularly Molly fish; therefore, this study aimed to highlights the description
of pancreatic tissue in Molly fish using light- and electron- microscopy, focusing
on the role of pancreatic immune cells and pancreatic acinar cells in immune
responses. Microscopic analysis revealed that the pancreas of Molly fish was composed
of intrahepatic, disseminated and compact parts. Exocrine pancreatic tissue
was diffusely extended within the hepatic tissue forming hepatopancreas. The disseminated
pancreas appeared as several irregular nodules of pancreatic tissue localized
within the mesenteric adipose tissue. The compact pancreas appeared as an oval
shaped body embedded within the mesenteric adipose tissue between the spleen
and the intestinal loops. Several telocytes and melanomacrophages were detected
within the disseminated pancreatic nodules. Moreover, dendritic cells were found in a
close association to the exocrine pancreatic acini. The pancreatic acinar cells showed
strong immunoreactivity to APG5, TGF-β, IL-1β, NF-κB, Nrf2, and SOX9 in both
hepatopancreas and disseminated pancreas of Molly fish. S100 protein revealed a
strong expression in the exocrine pancreatic acinar cells of disseminated pancreas
and also in the endocrine cells of the compact pancreas. In conclusion, findings of this
study suggest the potential role of the pancreas of the Molly fish in cell proliferation
and differentiation, proinflammatory cytokines stimulation, and regulation of both
innate and adaptive immunity.

This study sought to examine the ovarian cellular and stromal components of the zebrafish
(Danio rerio) throughout the spawning season using light and electron microscopic tools. The
ovaries of zebrafish showed oocytes in all stages of follicular development and degeneration (atresia).
Six stages of oogenesis were demonstrated: oogonia, early oocytes, late oocytes, vacuolated follicles,
the yolk globule stage (vitellogenesis), and mature follicles. The SOX9 protein was expressed in the
ooplasm of the primary and previtellogenic oocytes and the theca cell layer of the mature follicles.
Myostatin was expressed in the granulosa and theca cells. Many stem cells in the ovarian stroma
expressed myostatin and SOX9. During the spawning season, the EM results indicated that the
zona radiata increased in thickness and was crossed perpendicularly by pore canals that contained
processes from both oocytes and zona granulosa. The granulosa cells contained many mitochondria,
rER, sER, and vesicles. Meanwhile, the thecal layer consisted of fibroblast-like cells. Atretic follicles
could be demonstrated that involved both oocytes and their follicular walls. Several types of cells
were distinguished in the ovarian stroma, including mast cells, telocytes, lymphocytes, fibroblasts,
endocrine cells, macrophages, adipocytes, dendritic cells, and steroidogenic (stromal) cells. The ovary
of the zebrafish serves as a model to investigate follicular development.

The molly fish is a member of viviparous teleosts that are characterized by the fusion
of the right and left ovaries during their early embryonic development. This fusion results in a
singular and saccular ovary, where the germinal epithelium lines the internal lumen. The present
study aimed to identify the immune cells in the ovarian stroma of Molly fish during the breeding
season using histological and immunohistochemical analysis. Histological examination of the ovaries
displayed oocytes at all different stages of development and degeneration. The ovocoel, a lymphfilled
space, remains in the center of the ovary and branches posteriorly, creating the lumen of the
gonoduct. The ovarian wall is composed of three layers: the mesothelium, tunica albuginea, and
germinal epithelium. The developing ova were held together by the stroma, which consisted of
vascular collagenous connective tissue clustered with immune cells. Immunohistochemical analysis
revealed the presence of clusters of macrophages expressing APG5, IL-1β, TGF-β, S100, NF-κB,
CD68, Iba-1, and Ach. Monocytes demonstrated positive immunoreactivity for both APG5 and IL-1β,
whereas dendritic cells expressed only APG5. Furthermore, rodlet cells exhibited immunoreactivity
for S100 protein, IL-1β, NF-κB, CD68, Nrf2, Ach, myostatin, SOX9, and Iba-1. In contrast, stem cells
displayed immunoreactivity for Nrf2, myostatin, and SOX9. In conclusion, the ovarian stroma of
Molly fish demonstrated a notable presence of immune cells, indicating their active involvement in
immune reactions.

Since the discovery of aflatoxins in the 1960s, knowledge in the mycotoxin research field has increased dramatically. Hundreds of review articles have been published summarizing many different aspects, including mycotoxin contamination per country or region. However, mycotoxin contamination in the Arab world, which includes 22 countries in Africa and Asia, has not yet been specifically reviewed. To this end, the contamination of mycotoxins in the Arab world was reviewed not only to profile the pervasiveness of the problem in this region but also to identify the main knowledge gaps imperiling the safety of food and feed in the future. To the best of our knowledge, 306 (non-)indexed publications in English, Arabic, or French were published from 1977 to 2021, focusing on the natural occurrence of mycotoxins in matrices of 14 different categories. Characteristic factors (e.g., detected mycotoxins, concentrations, and detection methods) were extracted, processed, and visualized. The main results are summarized as follows: (i) research on mycotoxin contamination has increased over the years. However, the accumulated data on their occurrences are scarce to non-existent in some countries; (ii) the state-of-the-art technologies on mycotoxin detection are not broadly implemented neither are contemporary multi-mycotoxin detection strategies, thus showing a need for capacity-building initiatives; and (iii) mycotoxin profiles differ among food and feed categories, as well as between human biofluids. Furthermore, the present work highlights contemporary legislation in the Arab countries and provides future perspectives to mitigate mycotoxins, enhance food and feed safety, and protect the consumer public. Concluding, research initiatives to boost mycotoxin research among Arab countries are strongly recommended.

Monosodium glutamate (MSG) consumption is responsible for a wide spectrum of health
hazards including nephrotoxicity. The search for phytochemical strategies having broad
safety profile to counter MSG toxicity is worthwhile. Nigella sativa L. seed (NSS) is very
promising in this regard owing to its antioxidant and cytoprotective nature. Therefore, we
attempted to investigate the potential protective effect of NSS on MSG-induced renal
toxicity in rats. To accomplish this objective, fifteen adult Wistar albino rats were randomly
and equally divided into three groups for 21 days: the control group received no treatment,
MSG group supplemented with MSG at a dose of 30 g/kg feed, and MSG + NSS group
supplemented with MSG at the same previous dose in conjugation with NSS at a dose of
30 g/kg feed. MSG and its combination with NSS failed to cause any significant difference
in the kidney function parameters in comparison with the control. A significant elevation in
lipid peroxides (LPO) level, glutathione-S-transferase activity and total antioxidant capacity
(TAC) and a significant reduction in superoxide dismutase activity were found in MSG
group. LPO level and TAC in MSG intoxicated rats significantly normalized by NSS
ingestion. NO level showed absence of significant difference among all experimental
groups. MSG elicited histopathological lesions such as decreased glycoprotein content
and fibrosis however, NSS succeeded in enhancing all these features. MSG group showed
positive glutathione reductase and superoxide dismutase 2 immuno-expression whereas,
MSG + NSS group showed weak immunostaining. A significant increase in the number of
apoptotic cells was observed in MSG group compared to the control. On the other hand,
MSG + NSS group exhibited a significant decrease in the number of apoptotic cells. NSS
mitigated MSG-induced renal impairments by ameliorating oxidative stress and exerting
anti-apoptotic effect.