Wall Of Buccal Cavity Research Articles

Redescription of <i>Argulus mongolianus</i> (Crustacea: Branchiura: Argulidae), an Ectoparasite of Freshwater Fishes in East Asia, with Its First Record from Japan

Both adult females and males of Argulus mongolianus Tokioka, 1939 were collected from the buccal cavity wall and body surface of freshwater fishes in Lake Izunuma and Lake Uchinuma, Miyagi Prefecture, northen Honshu, Japan. The original description of the species was insufficient, based on a single female from Inner Mongolia, China, and no further description has been made to date. Thus, this paper redescribes A. mongolianus based on the newly-collected specimens, including the first description of the male. This represents the first record of A. mongolianus from Japan. The infected fishes were largemouth bass, Micropterus salmoides (Lacepède, 1802), common carp, Cyprinus carpio Linnaeus, 1758, Japanese white crucian carp, Carassius cuvieri Temminck and Schlegel, 1846, and silver crucian carp, Carassius sp. The three species other than common carp are new host records for A. mongolianus. This parasite was most probably introduced with an unspecified freshwater fish from China into Japan.

Angling-induced injuries have a negative impact on suction feeding performance and hydrodynamics in marine shiner perch, Cymatogaster aggregata.

Fishing is a popular and lucrative sport around the world and, in some cases, may contribute to declining fish stocks. To mediate this problem and maintain fish biomass in aquatic ecosystems, catch-and-release fishing, whereby a fish is caught and immediately released, has been implemented in many countries. It is unclear whether the injuries to the mouth that are caused by the hook have an impact on feeding performance of fishes. Using high-speed video and computational fluid dynamics (CFD), we asked whether injuries around the mouth caused by fishing hooks have a negative impact on suction feeding performance (measured as maximum prey velocity) of the commonly angled marine shiner perch (Cymatogaster aggregata). We hypothesized that fish with mouth injuries would exhibit decreased feeding performance compared with controls. Ten shiner perch were caught using scientific angling and 10 were caught using a seine net. Feeding events were then recorded at 500 frames per second using a high-speed camera. Compared with the control group, maximum prey velocity was significantly lower in the injured group (P<0.01). Maximum gape, time to peak gape, maximum jaw protrusion and predator-prey distance were comparable between the control and injured groups, leading us to conclude that the injury-induced hole in the buccal cavity wall reduced the pressure gradient during mouth expansion, thereby reducing the velocity of water entering the fish's mouth. This was confirmed with our CFD modelling. Fishing injuries in nature are likely to depress feeding performance of fish after they have been released, although it is currently unclear whether this has a significant impact on survival.

Paroctonchus nanjiensis gen. nov., sp. nov. (Nematoda, Enoplida, Oncholaimidae) from intertidal sediments in the East China Sea.

Paroctonchus nanjiensis gen. nov., sp. nov. is described from a sand beach in the China Nanji Islands Natural Reserve in the East China Sea. Paroctonchus nanjiensis is distinct in the family Oncholaimidae in having more than three teeth, a character found otherwise only in the monotypic genera Octonchus and Patagonema. The new genus and species differs from Octonchus and Patagonema in the number and pattern of teeth, bearing three large teeth with the left ventrosublateral one the largest plus about 27 small teeth distributed on the wall of buccal cavity. By contrast, Octonchus possesses one large tooth plus eight small teeth, while Patagonema has three large teeth with the right ventrosublateral one the largest plus 12 small teeth on three mandibular ridges. Moreover, Paroctonchus nanjiensis differs from Octonchus also in position of the amphidial aperture (located in the middle portion of buccal cavity vs. at the base of buccal cavity), and from Patagonema in the absence of a demanian system (vs. present) and the presence of two subventral rows of wart-like precloacal supplements (vs. a ventral row of papillate supplements). We provide an improved diagnosis for the subfamily Octonchinae, and discuss the evolution of teeth in the family Oncholaimidae.

ヒラメのネオへテロボツリウム症

In the mid-1990s, wild olive flounder showing heavy anemia characterized by deformed erythrocytes with low-stained cytoplasm appeared in Japanese waters. Parasitological, histopathological and hematological studies and surveys revealed that the anemia was caused by the infection with the monogenean Neoheterobothrium hirame on the gill and buccal cavity wall of host. The parasite was later revealed to originally infect southern flounder Paralichthys lethostigma in north America and invade Japanese waters. Bathing in NaCl-supplemented seawater is effective to remove worms from fish. The parasite has been prevailing in wild stocks of olive flounder and may threat the stocks especially in warmer waters.

Carcinoma buccal cavity: Late presentation and salvage, experience from a North Indian center

Carcinoma buccal cavity, the most common oral cavity cancer was seen in our set up in more than 50% cases. Forty patients of carcinoma buccal cavity were studied at JN Medical College, Aligarh Muslim University, and Aligarh over a period of last 5 years (2003-2008). Mean age at presentation 36.5 years (30-55) years. Male: Female, 27:13. Most common association was with smoking and chewing tobacco and pan over a mean long period of 15 years (8-22 years). Most common location was lateral wall of buccal cavity over cheek area related to their typical chewing habit of keeping the tobacco over that area over a prolonged period. Most of them, more than 90% (36 cases) presented late involving both mucosa and skin and in 25% cases also involving the alveolus and mandible. Wide excision and modified radical neck dissection with or without mandibulectomy (marginal, partial or hemimandibulectomy) done in all cases. Reconstruction was done by pedicled pectoralis major (PM) and deltopectoral (DP), the workhorse flaps for head and neck reconstruction for mucosal lining and skin cover respectively in 25 cases. Five cases needed only lining done by PM flap. Ten cases were salvaged by pedicled forehead flap for both lining and cover. All the cases healed properly with acceptable results and good functional recovery. Two cases reported recurrence treated with postoperative radiotherapy. Poor socioeconomic status, smoking and chewing habit, poor oral hygiene, malnutrition and moreover lack of awareness led to late presentation. However, an attempt was made for salvage at our center.

Yeast-binding C-type lectin with opsonic activity from conger eel ( Conger myriaster) skin mucus

A mannose-specific lectin with agglutination activity against a yeast, Saccharomyces serevisiae, was purified from conger eel ( Conger myriaster) skin mucus. The lectin, named conCL-s, has a tetrameric structure consisting of two non-covalently associated dimers whose constituent monomers with a molecular mass of about 16,000 Da are linked by a disulphide bond. conCL-s is composed of 173 amino acid residues including a 24-residue signal peptide, and belongs to the C-type lectin family, which is typically characterized by binding to sugar in a Ca 2+-dependent manner. Nevertheless, conCL-s showed Ca 2+-independent activity in its yeast-binding. The gene expression of the lectin was widely detected in external and internal mucosal tissues, i.e., skin, gills, tongue, buccal cavity wall and esophagus. In these tissues, mRNA of conCL-s was exclusively distributed in club cells, which are one of the major components of the epidermis and mucosal epithelium in Anguilliforme species. conCL-s showed agglutination activity to a bacterium, Escherichia coli. Furthermore, attachment of the lectin to microspheres significantly enhanced their phagocytosis in conger eel macrophages. These findings suggest that conCL-s acts as an opsonin and plays an important role in the innate immunity on the body surface in conger eels.

Role of cellular response in elimination of the monogenean Neoheterobothrium hirame in Japanese flounder Paralichthys olivaceus

Adult worms of the blood-feeding monogenean parasite Neoheterobothrium hirame, which cause anemia in the Japanese flounder Paralichthys olivaceus, attach to the host fish by embedding their posterior part deeply into the host tissue. To investigate the possibility that cellular responses of the host fish can eliminate N. hirame, flounder were experimentally infected with N. hirame larvae and reared in either fed or starved conditions. Mature parasites were identified on the buccal cavity wall of the fish 33 d post-infection (Day 33). Monocytes/macrophages and granulocytes increased rapidly in the blood and infected sites after the appearance of mature parasites. These cells adhered to the tegument of the parasites. In addition, a few cells with large electron-dense granules (DGCs) were observed in the inflammatory foci. On Day 47, the tegument of some parasites collapsed partially and were phagocytosed by the infiltrated host cells. Some infiltrated cells adhered directly to the inner tissues of the parasites. On Day 54, in the fed fish group, the loss of the tegument led to damage of the parasites' inner tissue by a large number of infiltrated cells. In this group, the elimination of the parasites was noted from Day 47 to 54. These observations probably suggest that the cellular response of the host fish destructed the parasite's posterior part embedded in the tissue, thereby eliminating the parasites. On the other hand, a high mortality was observed in the starved group. The starved fish developed much more severe anemia than the fed fish, and the elimination of the parasites was not observed in this group. The results of the present study suggest that flounder can eliminate N. hirame if they are fed sufficiently.

Effects of Water Temperature on the Development of the Monogenean Neoheterobothrium hirame on Japanese Flounder Paralichthys olivaceus

Development and growth of the monogenean Neoheterobothrium hirame on Japanese flounder Paralichthys olivaceus were investigated at 15°C, 20°C and 25°C, and production of antibodies against N. hirame was monitored in relation to the development of the parasite. After settlement on the gill filaments, hematin cells in the gut wall of N. hirame were first observed on Day 17, Day 10 and Day 7 post-exposure (PE) of oncomiracidia at 15°C, 20°C and 25°C, respectively. The parasite started to move to the buccal cavity wall from Day 38, Day 24 and Day 24 PE and eggs were observed in the uterus from Day 59, Day 38 and Day 31 PE at each temperature, respectively. Intensity of infection decreased subsequently and infection persisted until Day 122, Day 66 and Day 52 PE, respectively. Antibody titers gradually increased from Day 52 PE at 15°C, while at 20°C and at 25°C, they rapidly increased after a decrease in the intensity and prevalence of the infections was observed. This suggests that the death of the parasite induces a host reaction, resulting in the production of antibodies against N. hirame.

Development of epidermal and mucosal galectin containing cells in metamorphosing leptocephali of Japanese conger

The epidermis of premetamorphic leptocephali of Japanese conger Conger myriaster consisted of only a few cell layers including congerin‐ (a galectin) containing club cells. The epidermis increased in thickness after metamorphosis, mainly due to a preponderant development of club cells. This suggested that the biological significance of congerins increased at this stage, which may be related to a change in life style. Epidermal mucous cells showed only limited distribution. Immuno‐positive cells in the mucosal epithelia of the buccal cavity wall and oesophagus were not found in the youngest individuals. Though these cells were observed at the commencement of metamorphosis, the development of the epithelia and club cells was apparently retarded compared to that of the epidermis. No immuno‐staining was found in the gills at any stages.

Galectin containing cells in the skin and mucosal tissues in Japanese conger eel, Conger myriaster: an immunohistochemical study

Congerin is a β-galactoside binding lectin (galectin) purified from the skin mucus of the Japanese conger, Conger myriaster. To clarify its tissue distribution and productive cells, several tissue samples including skin, buccal cavity wall, tang, pharynx, gills, esophagus, stomach, intestine, liver, kidney, spleen and ovary of conger were stained immunohistochemically using polyclonal rabbit anti-congerin serum. In the epidermis, a number of club cells were strongly stained. Because no agglutinating activity was detected in plasma, it appears evident that congerin is produced and secreted into mucus by those cells. In addition, congerin-positive club cells were distributed in the mucosal epithelium lining the digestive tract preceding the stomach and in the gills. These findings suggest that congerin participates in innate immunity on the intra- and the extra-body surface of the conger. The putative functions of club cells in fish and their contained lectin are discussed.

Microhabitats and Mode of Attachment of Neoheterobothrium hirame, a Monogenean Parasite of Japanese Flounder.

A survey of Neoheterobothrium hirame infection of Japanese flounder Paralichthys olivaceus in several places in Japan (Kyoto, Fukui and Ibaraki) was conducted to examine the relationship between the development of the parasite and its microhabitats. The parasite first attached to the gill filaments, then migrated to the gill arches/rakers and finally moved to the buccal cavity wall. This migration was associated with growth and maturity of the parasite. Some worms already reached maturity on the gill rakers, but produced eggs only on the buccal cavity wall. The histology of infected tissues was examined to determine the mode of attachment and pathological effects of the parasite. On the gill filaments, the parasite used, at first, marginal hooks and hamuli to attach to the proximal region of the secondary gill lamellae and later, clamps to grasp these lamellae. On the gill arches/rakers, clamps were used to attach to the epithelium. On the buccal cavity wall, clamps were used initially for attachment to the tissue surface but later the haptor penetrated the underlying connective and muscle tissues until the haptor and almost the entire isthmus region were embedded deeply in the host tissue. Only a mild inflammatory response was observed on the gill filaments and in the epithelium of the gill arches/rakers, respectively, whereas a strong host response and necrosis were associated with the prolonged attachment of the parasite to the buccal cavity wall.

A Study of Long-term Changes in Summer Infection Levels of Japanese Flounder Paralichthys olivaceus with the Monogenean Neoheterobothrium hirame in the Central Sea of Japan, with an Application of a New Technique for Collecting Small Parasites from the Gill Filaments.

Neoheterobothrium hirame infection of 0-year wild Japanese flounder Paralichthys olivaceus was investigated. This study was based on annual samples (preserved in formalin or alcohol) totalling 316 fish caught off Igarashi-hama in July and/or August of 1989-1993 and 505 fish caught off Murakami City in August of 1993-1999, Niigata Prefecture. A stirring method was developed to collect the monogenean from the fixed gill filaments. All the parasites were dislodged from the fixed gill filaments by stirring gills of individual hosts in 150 mL of water with a magnet (40 mm long and 8 mm in diameter) at 1150-1200 rpm for 20 min and 30 min for the 0-year fish and 1-year fish, respectively. Adult parasites were macroscopically observed on the buccal cavity wall, whereas immature ones on the gill arches and rakers were detected under a stereomicroscope. No N. hirame was found from 1989 to 1992. The earliest records were from samples caught off Igarashi-hama and Murakami City in 1993, though the prevalence of infection was very low. The parasite occurrence changed annually in the Murakami samples. The annual fluctuations may have been influenced by the infection level of co-existing 1-year fish and the population size of 0-year fish recruited each year. It is inconclusive whether or not the monogenean is an indigenous parasite of Japanese flounder in this area.

Neoheterobothrium hirame sp. nov. (Monogenea: Diclidophoridae) from the Buccal Cavity Wall of Japanese Flounder Paralichthys olivaceus.

Neoheterobothrium hirame sp. nov.is described, based on specimens collected from the buccal cavity wall of Japanese flounder, Paralichthys olivaceus, caught in Wakasa Bay, Japan. The parasite was 14-33 mm in total length, with 4 pairs of clamps on the pedunculated haptor, which was separated from the body proper by a long isthmus. The presence of a pair of peripheral intestinal branches running along both sides of body, in addition to the main pair of medial branches, is described here for the first time.The new species can be distinguished from N. affine (Linton, 1898) --the most closely related species and the type species of the genus--by the relatively large body proper and the shorter isthmus. The taxonomic status of other related species is discussed. The generic diagnosis proposed by Price (1943), Yamaguti (1963) and Mamaev (1987) is emended.

Cobbionema capense n.sp. from Swartkops estuary, Port Elizabeth (Nematoda: Selachinematidae)

Cobbionema capense n.sp. from Swartkops estuary near Port Elizabeth is described. The new species is distinguished by the moderately cuticularized buccal cavity wall and teeth ridges.