A tumorlike papilliform growth in the brown shrimp (Penaeus aztecus)

A brown shrimp, Penaeus aztecus, from an experimental pond of the Texas Parks and Wildlife Department's Marine Laboratory at Palacios, Texas, possessed a papilliform tumorlike growth on the right ventrolateral aspect of the sixth abdominal segment. Gross and histological study revealed the lesion to be confluent with the carapace, epidermis, and subepidermal connective tissue. The growth, tentatively diagnosed as a benign neoplasm, consists of grossly hypertrophied and normal tissue elements.     

Morphology of the Midgut–Hindgut Juncture in the Ghost Shrimp Lepidophthalmus louisianensis (Schmitt) (Crustacea: Decapoda: Thalassinidea)

Abstract Unique morphological structures occur near the midgut–hindgut juncture in decapod crustaceans, and neither their fine structure nor function are well understood. In the ghost shrimp Lepidophthalmus louisianensis. structures associated with this juncture include an elongate posterior midgut caecum (PMGC) extending into the abdominal hemocoel, a massive swelling of acinar glands encasing the juncture, and a dorso-lateral valve complex involving cuticularized lumenal surfaces of the anterior hindgut. Vivisection, histological studies (LM, TEM) and paraffin-carving (SEM) have been applied to reconstruct morphology of these components and characterize constituent tissues. The lumen of the PMGC is lined by very elongate columnar cells underlain by a thin layer of circular muscle. The hemocoelic surface of the PMGC is covered by cells richly endowed with unique lamellar bodies. The acinar glands are composed of multiple rosettes of secretory cells, from which products appear to empty into the anterior extreme of the hindgut. The dorso-lateral valve complex of the hindgut consists of anterior and posterior components, differing in strength of lumenal ridging and microdentition of the cuticular lining. Unique features of these structures may relate to behavioral, feeding and metabolic adaptations in this obligate fossorial crustacean.     

Clearing mechanisms of Vibrio vulnificus biotype I in the black tiger shrimp Penaeus monodon

Vibrio species' infections are a common sequelae to environmental stress or other disease processes in shrimp, but the mechanism by which the shrimp eliminate the bacteria is poorly understood. In this study, the penetration, fate and the clearing of V. vulnificus were investigated in Penaeus monodon. A bacterial disease isolate from a shrimp farm was identified as V. vulnificus biotype I. Polyclonal antiserum was raised in rabbits against the bacterium and the specificity was verified by ELISA and immunoblot against a range of Vibrio spp. and other gram-negative bacteria. The bacteria were then administered to P. monodon juveniles by injection, immersion and oral intubation. An indirect immunoperoxidase technique was employed in a time course study to follow the bacteria and bacterial antigens in the tissue of the shrimp. Bacteria were cleared by a common route, regardless of the method of administration. Observations in immersion challenge were similar to a combination of those for oral and injection challenges. With immersion, bacteria entered the shrimp through damaged cuticle or via insertion points of cuticular setae. Shortly after entry, whole bacterial cells were observed in the haemolymph and connective tissue. They were either phagocytosed by haemocytes, or broken down outside host cells. Haemocytes containing bacterial cells or antigens (HCB) were observed in the connective tissue and haemolymph. HCB accumulated around the hepatopancreas, midgut, midgut-caecum, gills, heart and lymphoid organ. Free bacterial antigens also accumulated in the heart and lymphoid organ. Bacteria entering through the mouth by oral intubation or immersion were broken down so that only soluble or very fine particles entered the hepatopancreas. Bacterial antigens passed through the hepatopancreas into the haemolymph. Antigens were initially observed in the haemolymph sinuses and subsequently accumulated in the heart and lymphoid organ. Bacterial antigens were released from the shrimp, initially through the gills and subsequently through hepatopancreatic B-cells, branchial podocytes and sub-cuticular podocytes.     

Morphology of the Harderian gland of the Gecko, Tarentola mauritanica

The Harderian gland of the gecko, Tarentola mauritanica, was studied at the histological, histochemical, and ultrastructural levels. It is a nonlobate compound acinar gland surrounded by a thin capsule of connective tissue. Numerous connective tissue-type mast cells, ultrastructurally similar to those described in other higher vertebrates, were identified in the interstitial tissue between the acini. Pyramidal or columnar-shaped secretory glandular cells were observed in the acini. In the glandular cells, two types of structures could be distinguished on the basis of their high or low electron density. Lipid droplets were found in the cytoplasm of the Harderian gland of both sexes. Histochemical tests showed that the Harderian gland of the gecko is a seromucous gland. The secretion is essentially merocrine, although an apocrine type of secretion is sometimes observed.     

Histopathology in Leuciscus cephalus (Pisces: Cyprinidae) resulting from infection with Pomphorhynchus laevis (Acanthocephala).

The histopathology present in Leuciscus cephalus Risso 1826 from the River Po, naturally infected with the acanthocephalan Pomphorhynchus laevis Müller 1776, was studied and described. The parasite was only found within the host's digestive tract, and a density of 10 P. laevis per square centimeter was common. On histological examination it was noticed that both male and female parasites penetrated deeply through all the layers of the host digestive tract by means of their slender neck, bulb and proboscis; thus the bulb and proboscis become encapsulated beneath the serosa and mesentery. As a result, the presence of a capsule was noticed on the external surface of the host digestive tract. P. laevis caused local damage to the intestinal wall, and the parasite elicited an intense host reaction. The response of L. cephalus at the attachment site of the acanthocephalan was hyperplasia of host connective tissue, with cellular infiltration. In a few hosts, the presence of a fibrous nodule on the outer surface of the alimentary canal was observed.     

Morphology and glycoconjugate histochemistry of the palpebral glands of the adult newt, Notophthalmus viridescens.

The eyelids of the newt were studied in 10 microns serial paraffin and 1-2 microns plastic sections using standard histological stains and special stains for glycoconjugates. The eyelids contain four different glands. Simple acinar serous and simple acinar mucous glands occur in the skin; unicellular mucous glands occur in the conjunctiva; and convoluted tubular seromucous glands are present in connective tissue beneath the conjunctiva. The first two are identical to cutaneous glands found elsewhere on the head and body. The simple acinar serous glands are surrounded by myoepithelial cells and release their secretion, which is composed largely of proteins with minimal glycoconjugate content, by a holocrine mechanism. The secretory product of the simple acinar mucous glands is composed of neutral glycoconjugates with a minor content of acidic glycoconjugates; the mucin exhibits strong PAS and PAPD staining and weak staining by AB and PAPS methods. The unicellular conjunctival mucous glands secrete both neutral and acidic glycoconjugates as shown by positive reactions with PAS, PAPD, PAPS, and AB methods. Convoluted tubular seromucous glands in the ventral eyelid synthesize both proteins and neutral glycoconjugates. The mucous secretions of the conjunctival glands probably provide lubrication and protection for the cornea.     

Embryonic development of the bovine pineal gland (Bos taurus) during prenatal life (30 to 135 days of gestation)

The ontogenesis of the pineal gland of 30 bovine embryos (Bos taurus) has been analysed from 30 until 135 days of gestation by means of optical microscopy and immunohistochemical techniques. For this study, the specimens were grouped into three stages in accordance with the most relevant histological characteristics: Stage 1 (30 to 64 days of prenatal development); Stage 2 (70 to 90 days) and Stage 3 (106 to 135 days). In the cow, it is from 30 days of gestation that the first glandular outline becomes differentiated from the diencephalic ependyma of the third ventricle. This differentiation includes the phenomena of proliferation and multiplication of the ependymal cells that form the epithelium of the pineal outline in development. At 82 days of intrauterine life, in the interior of the pineal parenchyma, we witnessed some incipient pseudoglandular structures that at 135 days were well differentiated. The pineal parenchyma displays a cytology made up of two cellular types of structurally distinct characteristics: pinealoblasts and interstitial cells. Both cellular types begin differentiation at 70 days of embryonic development, the pinealoblasts being greater in number than the interstitial cells. The glandular stroma is formed from the capsular, trabecular and the perivascular connective tissue, filling the interparenchymal space. A dense network of capillaries, which drive across the trabecular connective tissue towards the central glandular zone where their density increases and their calibre is reduced, complete the glandular structure. GFAP positive cells were observed in the embryonic pineal parenchyma in stage 3. At 135 days of gestation, NPY positive fibers entered the pineal gland through the pineal capsule occupying a perivascular localization. Morphological studies of this nature are vital for future use as parameters, indicative of the functional activity of the bovine pineal gland during embryonic development.     

Molecular cloning and characterization of proliferating cell nuclear antigen (PCNA) from Chinese shrimp Fenneropenaeus chinensis

The proliferating cell nuclear antigen gene was cloned from Fenneropenaeus chinensis (FcPCNA). The full-length cDNA sequence of FcPCNA encodes 260 amino acids showing high identity with PCNAs reported in other species. FcPCNA expressed especially high in proliferating tissues of shrimp such as haematopoietic tissue (HPT) and ovary. In order to understand the response of HPT to bacteria and virus challenge, mRNA level of FcPCNA in HPT was analyzed after shrimp were challenged by Vibrio anguillarum and white spot syndrome virus (WSSV). FcPCNA expression in HPT of shrimp was responsive to WSSV and Vibrio challenge, but different expression profiles were obtained after challenge by these two pathogens. The data provide additional information to understand the defense mechanisms of shrimp against virus and bacteria.     

Genetic diversity of attached bacteria in the hindgut of the deposit-feeding shrimp Neotrypaea (formerly Callianassa) californiensis (decapoda: thalassinidae)

Microbial colonization of marine invertebrate guts is widespread, but in general the roles that these bacteria play in the nutrition of their hosts are unknown. To examine the diversity and potential nutritional roles of hindgut microbiota in a deposit feeder, PCR-amplified 16S rRNA genes were cloned from the bacterial community attached to the hindguts of the thalassinid shrimp Neotrypaea californiensis exposed to different feeding treatments. Partial 16S rDNA sequences were analyzed for 30 clones for three shrimp per treatment for a total of 270 clones. No effects of host starvation or high-protein diets were apparent on hindgut bacterial community composition. Diversity analyses indicated high variability between bacterial communities in individual shrimp hindguts, but partial 16S rDNA sequences revealed remarkable species-level similarity (>98%) within clusters of sequences from the different shrimp hindguts, and many sequences from different shrimp hindguts were identical. Sequences belonged to three main groups of bacteria: Cytophaga-Flavobacteria-Bacteroides (CFB), proteobacteria, and gram-positives. Of the 270 sequences, 40% belonged to the alpha-proteobacteria, > or = 5% each to the gamma- and epsilon -proteobacteria, and > or =20% each to the gram-positive and CFB groups. All except one sequence are novel with < or = 95% sequence similarity to known genes. Despite weak similarity to known taxa,about 75% of the sequences were most closely related to known symbiotic and sedimentary bacteria. The bacteria in shrimp hindguts represent new species that have not yet been en-countered in other environments, and gut environments may be a rich source of the difficult-to-culture and novel components of marine bacterial diversity.     

Development of monoclonal antibodies for detection of necrotizing hepatopancreatitis in penaeid shrimp

Monoclonal antibodies (MAbs) were produced against necrotizing hepatopancreatitis bacteria (NHP-B) of penaeid shrimp. The MAbs tested in dot-immunoblot (D-IB) assays were capable of detecting the NHP-B in hepatopancreas samples collected from moribund juvenile Litopenaeus vannamei during an experimentally induced NHP-B infection. The MAbs were also screened by immunohistochemistry (IHC) using case submissions that were determined to be infected not only by histology, but also polymerase chain reaction (PCR) and in situ hybridization (ISH) assays using specific digoxigenin (DIG)-labeled probes on histological sections prepared from naturally infected shrimp. Two of the MAbs were chosen for development of detection methods for NHP. The MAbs were tested using IHC methods on Davidson's alcohol-formalin-acetic acid (AFA) fixed tissue sections and identified NHP-B infected cells and tissues in a pattern similar to that seen with DIG-labeled NHP-specific gene probes. None of the MAbs reacted with tissue from specific pathogen-free (SPF) shrimp or with shrimp tissues infected with a rickettsia-like bacteria, Vibrio sp., Campylobacter sp., and Spiroplasma sp. The MAbs were found to be negative against these other organisms, demonstrating that they are species specific and useful for rapid diagnostic detection of NHP-B.     

Close association of centroacinar/ductular and insular cells in the rat pancreas

Close contacts between endocrine insular cells and exocrine acinar, centroacinar and ductular cells occur frequently in the rat pancreas as seen by both light and electron microscopy. Islets of Langerhans are surrounded incompletely by a thin connective tissue capsule or mantle but numerous exocrine-endocrine cell contacts occur at the periphery, which is irregular with considerable "intermingling" of the two cell types. Centroacinar and ductular cells are seen to be in contact with all endocrine cell types but most commonly insulin-secreting B-cells. The basal surface of centroacinar cells in the region of contact may be extensive, sometimes with overlap of basal processes of these cells and their lateral extension between acinar and insular cells. The areas of contact contain no connective tissue or basal lamina and show no surface specializations. The presence of both the "open" and "closed" type of enteroendocrine cells within acini is confirmed, some also being in contact with centroacinar cells. The functional significance of these exo-endocrine cell contacts is discussed in terms of the endocrine-acinar portal system, possible direct paracrine secretion, compartmentalization within the islet, and the known effects of islet hormones on exocrine secretion. Also relevant is the developmental origin of islets from ductal tissue and the cellular origin of some tumours, e.g., insulinomas, from duct cells.     

Microbial Adjuvant and Autoimmunity

Definite lesions in the exocrine pancreas were produced when SMA mice were immunized eight times at intervals of 30 days with a mixture of extract of pooled pancreas from syngeneic mice and the capsular polysaccharide of Klebsiella pneumoniae type 1 Kasuya strain (CPS-K), whereas no pancreatic lesions were produced in mice given CPS-K alone or pancreatic extract alone. The typical histological changes were characterized by infiltration with lymphocytes, plasma cells, and other mononuclear cells, degeneration and lysis of the acinar cells, destruction of the lobular architecture, and replacement by fatty tissue and fibrous connective tissue. The endocrine islets were well preserved. No specific histological changes were produced in the organs other than the pancreas in these mice. Most of mice immunized with pancreatic extract mixed with CPS-K produced serum precipitins to syngeneic pancreatic antigens. However, severe pancreatic lesions were also produced in mice showing no definite precipitin production.     

The cellular matrix: a feature of tensile bearing dense soft connective tissues

The term connective tissue encompasses a diverse group of tissues that reside in different environments and must support a spectrum of mechanical functions. Although the extracellular matrix of these tissues is well described, the cellular architecture of these tissues and its relationship to tissue function has only recently become the focus of study. It now appears that tensile-bearing dense connective tissues may be a specific class of connective tissues that display a common cellular organization characterized by fusiform cells with cytoplasmic projections and gap junctions. These cells with their cellular projections are organised into a complex 3-dimensional network leading to a physically, chemically and electrically connected cellular matrix. The cellular matrix may play essential roles in extracellular matrix formation, maintenance and remodelling, mechanotransduction and during injury and healing. Thus, it is likely that it is the interaction of both the extracellular matrix and cellular matrix that provides the basis for tissue function. Restoration of both these matrices, as well as their interaction must be the goal of strategies to repair these connective tissues damaged by either injury or disease.     

Morphological changes in the anterior lobe of the hypophysis in allotransplantation]

Under study were histological changes resulting from rejection of adenohypophysis allotransplantat without special influence upon the recipient immunity. The allotransplantat rejection was established to be accompanied by pronounced morphological changes in the adenohypophysis. Delta-basophils were the first to loose their granules, and beta-basophils showed more moderate degranulation. Acidophils were preserved for a longer period. The chromophobes were more resistant cellular elements. Simultaneously the cells were dying at all stages of their conversion. The fibrous connective tissue alone was observed at the site of allotransplantat 32-35 days after transplantation.     

Preservation of necrotizing hepatopancreatitis bacterium (NHPB) by freezing tissue collected from experimentally infected Litopenaeus vannamei

Necrotizing hepatopancreatitis (NHP), a severe disease of penaeid shrimp, is caused by bacteria (NHPB) that have previously been demonstrated to reside in tubular epithelial hepatopancreatic (HP) cells of infected shrimp. There has yet to be a successful in vitro culture method to grow the intracellular organism; therefore, it must be propagated in vivo via transmission from NHPB-infected shrimp to healthy individuals. In our studies, NHPB propagation tanks containing infected shrimp were used to maintain a constant supply of organisms for experiments. In order to develop a method for storing infectious NHPB material for future challenge studies, we collected HP tissue containing NHPB by flash freezing whole, fresh HPs at -80 degrees C for up to 80 d and used it to successfully infect specific pathogen-free Litopenaeus vannamei per os in controlled experiments. HP tissue samples were collected from dead shrimp, and PCR was performed to confirm the presence of NHPB. Our results demonstrate that the infectivity of NHPB in tissue is not altered after being frozen at -80 degrees C when compared to NHPB in fresh tissue. Thus, the continual propagation of NHPB in vivo is not required to assure a source of the infectious agent.     

Degeneration of the tongue of Boops [(Boops boops L., 1758) (Teleost, Sparidae)] parasitized by Meinertia oestroides (Risso, 1826) (Isopoda, Flabellifera, Cymothoidae) (author's transl)

Host fishes (Boops boops) parasitized by the cymothoid isopod Meinertia oestroides show an atrophied tonuge: its length and its initial weight can decrease of about 50%. These morphological variations are connected with deep histological alterations, such as: A more or less important vanishing of epidermis. A disorganization of the connective tissue, by numerous invading blood cells. A total vanishing of cargilage and a partial vanishing of bone, resulting from the lysis of their own fundamental substance.     

Virus diseases of farmed shrimp in the Western Hemisphere (the Americas): a review

Penaeid shrimp aquaculture is an important industry in the Americas, and the industry is based almost entirely on the culture of the Pacific White Shrimp, Litopenaeus vannamei. Western Hemisphere shrimp farmers in 14 countries in 2004 produced more than 200,000 metric tons of shrimp, generated more than $2 billion in revenue, and employed more than 500,000 people. Disease has had a major impact on shrimp aquaculture in the Americas since it became a significant commercial entity in the 1970s. Diseases due to viruses, rickettsial-like bacteria, true bacteria, protozoa, and fungi have emerged as major diseases of farmed shrimp in the region. Many of the bacterial, fungal and protozoan caused diseases are managed using improved culture practices, routine sanitation, and the use of chemotherapeutics. However, the virus diseases have been far more problematic to manage and they have been responsible for the most costly epizootics. Examples include the Taura syndrome pandemic that began in 1991-1992 when the disease emerged in Ecuador, and the subsequent White Spot Disease pandemic that followed its introduction to Central America from Asia in 1999. Because of their socioeconomic significance to shrimp farming, seven of the nine crustacean diseases listed by the World Animal Organization (OIE) are virus diseases of shrimp. Of the seven virus diseases of penaeid shrimp, five are native to the Americas or have become enzootic following their introduction. The shrimp virus diseases in the Americas are increasingly being managed by exclusion using a combination of biosecurity and the practice of culturing domesticated specific pathogen-free (SPF) stocks or specific pathogen-resistant (SPR) stocks. Despite the significant challenges posed by disease, the shrimp farming industry of the Americas has responded to the challenges posed by disease and it has developed methods to manage its diseases and mature into a sustainable industry.     

Quantitative dimensions of histopathological attributes and status of GSTM1-GSTT1 in oral submucous fibrosis

Oral submucous fibrosis (OSF) is a precancerous condition of the oral cavity and oropharynx and a significant number of such cases transform into oral squamous cell carcinoma (OSCC). Presently, diagnosis of OSF is done mainly through qualitative histopathological techniques and in the level of diagnostic molecular biology no specific genetic marker is evident. Keeping these facts in mind this study evaluates histopathological changes in the epithelium and subepithelial connective tissue of OSF through quantitative digital image analysis in respect to specific candidate features and analyses null mutations in the GSTM1 and GSTT1 by PCR amplification. The analysis revealed that there are subtle quantitative differences in the histological images of OSF compared to NOM. The thickness of the epithelium and cell population in its different zones, radius of curvature of rete-ridges and connective tissue papillae were decreased but length of rete-ridges and connective tissue papillae, fibrocity and the number of cellular components (predominantly inflammatory cells) in the subepithelial connective tissue were increased in OSF. The PCR study revealed that there is no significant difference in the allelic variants in GSTM1 between OSF and normal, while GSTT1 null gene showed significantly higher frequencies in this precancerous condition. This study establishes a distinct quantitative difference between normal oral mucosa (NOM) and OSF in respect to their histological features and GST null gene frequencies.     

Use of RT-PCR for diagnosis of infectious salmon anaemia virus (ISAV) in carrier sea trout Salmo trutta after experimental infection

This paper describes a new bacterial white spot syndrome (BWSS) in cultured tiger shrimp Penaeus monodon. The affected shrimp showed white spots similar to those caused by white spot syndrome virus (WSSV), but the shrimp remained active and grew normally without significant mortalities. The study revealed no evidence of WSSV infection using electron microscopy, histopathology and nested polymerase chain reaction. Electron microscopy indicated bacteria associated with white spot formation, and with degeneration and discoloration of the cuticle as a result of erosion of the epicuticle and underlying cuticular layers. Grossly the white spots in BWSS and WSS look similar but showed different profiles under wet mount microscopy. The bacterial white spots were lichen-like, having perforated centers unlike the melanized dots in WSSV-induced white spots. Bacteriological examination showed that the dominant isolate in the lesions was Bacillus subtilis. The occurrence of BWSS may be associated with the regular use of probiotics containing B. subtilis in shrimp ponds. The externally induced white spot lesions were localized at the integumental tissues, i.e., cuticle and epidermis, and connective tissues. Damage to the deeper tissues was limited. The BWS lesions are non-fatal in the absence of other complications and are usually shed through molting.     

Myxobolus cuneus n. sp. (Myxosporea) infecting the connective tissue of Piaractus mesopotamicus (Pisces: Characidae) in Brazil: histopathology and ultrastructure

The characteristics of Myxobolus cuneus n. sp. and its relationship to the host Piaractus mesopotamicus are described based on light and electron microscopy and histological observations. Polysporic plasmodia measuring 20 microm to 2.1 mm in size were found in 63.3 % of the P. mesopotamicus examined. The parasite was found in the gall bladder, urinary bladder, gills, spleen, fins, head surface, liver and heart. Generative cells and disporoblastic pansporoblasts occurred along the periphery of the plasmodia, and mature spores were found in the internal region. The mature spores had a pear shaped body in frontal view, with a total length of 10.0 +/- 0.6 microm and a width of 5.1 +/- 0.3 microm (mean +/- SD). The spore wall was smooth with sutural folds. The polar capsules were elongated, were pear shaped, and equal in size (length 5.7 +/- 03 microm; width 1.7 +/- 0.2 microm), with the anterior ends close to each other. The polar filaments were tightly coiled in 8-9 turns perpendicular to the axis of the capsule. The plasmodia were always found in connective tissue (wall of the arterioles of the gill filaments, serous capsule of the gall bladder, middle layer and subepithelial connective tissue of the urinary bladder, connective tissue between the rays of the fins, subcutaneous tissue of the head surface and fibrous capsule spleen). The parasite caused important damage in the gills, where development occurred in the wall of gill filament arterioles; a mild macrophage infiltrate was also observed. In advanced developmental stages, the plasmodia caused deformation of the arteriole structure, with a reduction and, in some cases, obstruction of the lumen. The parasite was found throughout the period studied and its prevalence was unaffected by host size, season or water properties.