Differential expression of neuropeptide F in the digestive organs of female freshwater prawn, Macrobrachium rosenbergii, during the ovarian cycle

Neuropeptide F is a key hormone that controls feeding in invertebrates, including decapod crustaceans. We investigated the differential expression of Macrobrachium rosenbergii neuropeptide F (MrNPF) in the digestive organs of female prawns, M. rosenbergii, during the ovarian cycle. By using RT-qPCR, the expression of MrNPF mRNA in the esophagus (ESO), cardia (CD), and pylorus (PY) of the foregut (FG) gradually increased from stage II and peaked at stage III. In the midgut (MG), hindgut (HG), and hepatopancreas (HP), MrNPF mRNA increased from stage I, reaching a maximal level at stage II, and declined by about half at stages III and IV (P < 0.05). In the ESO, CD, and PY, strong MrNPF-immunoreactivities were seen in the epithelium, muscle, and lamina propria. Intense MrNPF-ir was found in the MG cells and the muscular layer. In the HG, MrNPF-ir was detected in the epithelium of the villi and gland regions, while MrNPF-ir was also more intense in the F-, R-, and B-cells in the HP. However, we found little colocalization between the MrNPF and PGP9.5/ChAT in digestive tissues, implying that most of the positive cells might not be neurons but could be digestive tract-associated endocrine cells that produce and secrete MrNPF to control digestive organ functions in feeding and utilizing feed. Taken together, our first findings indicated that MrNPF was differentially expressed in digestive organs in correlation with the ovarian cycle, suggesting an important link between MrNPF, the physiology of various digestive organs in feeding, and possibly ovarian maturation in female M. rosenbergii.

Molybdenum and Cadmium exposure influences the concentration of trace elements in the digestive organs of Shaoxing duck (Anas platyrhyncha)

To investigate the toxic effects of Molybdenum (Mo) and Cadmium (Cd) on trace elements in digestive organs of Shaoxing duck (Anas platyrhyncha), 120 Shaoxing ducks were randomly divided into control group and 5 treatment groups which were treated with a commercial diet containing different dosages of Mo and Cd. On the 60th and 120th days, the beak, esophagus, glandular stomach, muscular stomach, small intestine, large intestine and feces were collected to determine contents of Mo, Cd, copper (Cu), iron (Fe), zinc (Zn) and selenium (Se), then correlation analysis was performed. The results showed that Cd content in digestive organs significantly increased in co-treated groups compared to single treated groups and Mo concentration increased in Mo-treated groups compared to control group, whereas Cu, Fe, Zn and Se concentrations in digestive organs decreased in co-treated groups. Furthermore, Cd and Mo were mainly accumulated in the small intestine and esophagus, respectively. There was a strongly positive correlation between Cd and Mo while they had negative correlation with Cu, Fe, Zn and Se, respectively. In feces, Mo and Fe contents in high dose of Mo group and high Mo combined with Cd group were significantly higher than those in control group, and Cu content in all treated groups significantly increased and Cd, Zn and Se concentrations had no difference. The results indicated that dietary Mo or/and Cd might disturb homeostasis of trace elements in digestive organs of Shaoxing duck. Moreover, the two elements presented a synergistic relationship.

Aryl hydrocarbon receptor 2 mediates the toxicity of Paclobutrazol on the digestive system of zebrafish embryos

Paclobutrazol (PBZ), a trazole-containing fungicide and plant growth retardant, has been widely used for over 30 years to regulate plant growth and promote early fruit setting. Long-term usage of PBZ in agriculture and natural environments has resulted in residual PBZ in the soil and water. Chronic exposure to waterborne PBZ can cause various physiological effects in fish, including hepatic steatosis, antioxidant activity, and disruption of spermatogenesis. We have previously shown that PBZ also affects the rates of zebrafish embryonic survival and hatching, and causes developmental failure of the head skeleton and eyes; here, we further show that PBZ has embryonic toxic effects on digestive organs of zebrafish, and describe the underlying mechanisms. PBZ treatment of embryos resulted in dose-dependent morphological and functional abnormalities of the digestive organs. Real-time RT-PCR and in situ hybridization were used to show that PBZ strongly induces cyp1a1 expression in the digestive system, and slightly induces ahr2 expression in zebrafish embryos. Knockdown of ahr2 with morpholino oligonucleotides prevents PBZ toxicity. Thus, the toxic effect of PBZ on digestive organs is mediated by AhR2, as was previously reported for retene and TCDD. These findings have implications for understanding the potential toxicity of PBZ during embryogenesis, and thus the potential impact of fungicides on public health and the environment.

Carcinoid Tumors of Digestive Organs: a Clinicopathologic Study of 13 Cases

The author investigated clinicopathologic features of 13 cases of carcinoid tumor in the digestive organs. The 13 cases of carcinoid were identified from 18,267 pathological specimens of digestive organs in the last 10 years in our pathology laboratory. The tumor locations were rectum in 9 cases, duodenum in 2 cases, liver in 1 case, and stomach in 1 case. The age of the patients ranged from 52 to 82 years with a mean of 63 years. Male to female ratio was 7 : 6. The presenting symptoms were abnormal pain in 3 cases and asymptomatic in 10 cases. None of the cases showed carcinoid syndrome. The diameter ranged from 5 mm to 25 mm in gastrointestinal carcinoids, and 60 mm in the hepatic carcinoid. The treatment was endoscopic mucosal resection in 10 cases and surgical resection in 3 cases. The outcome is good except for hepatic atypical carcinoid which showed metastases and died of systemic metastasis. Histologically, 12 carcinoid tumors were typical carcinoids, and one (liver) was atypical carcinoid. Organoid pattern was present in 12 cases. Trabecular arrangement, ribbon arrangement, rosette formation, and pseudoglandular arrangement were recognized in 12 cases, in 8 cases, in 7 cases, and in 5 cases, respectively. Immunohistochemically, tumor cells were positive for at least one of pan-neuroendocrine markers including chromogranin, synaptophysin, neuron-specific enolase, CD56, and glucagon. Of these, synaptophysin was positive in 11/13 (85%), neuron-specific enolase 10/13 (80%), chromogranin 8/13 (62%), CD56 6/13 (46%), and glucagon 4/13 (31%). In summary, the author reported the incidence of digestive organ carcinoid tumors, and the clinicopathologic features of the 13 cases with carcinoid.

Effect of dietary protein level and origin on the redox status in the digestive tract of mice

The present study was undertaken to evaluate the effects of high protein (soybean protein or casein) on the balance between production of free radicals and antioxidant level in digestive organs of mice. For this purpose, male (C57BL/6J) mice were adapted to experimental diets containing soybean protein or casein with 20% (normal protein diets, NPDs) or 60% (high protein diets, HPDs), and HPDs supplemented with 0.06g/kg cysteamine. After two weeks of feeding, oxidative and antioxidative parameters in duodenum, liver and pancreas were measured. The results show that ingestion of high protein markedly increased contents of superoxide anion and malondialdehyde (MDA), decreased activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and Na⁺ K⁺-ATPase, and content of reduced glutathione (GSH) in digestive organs of mice (P<0.05). Levels of oxidative parameters were lower and antioxidant capacity of both enzyme and non-enzyme was higher in mice fed with soybean protein than those fed with casein. In groups fed HPDs supplemented with cysteamine, oxidative stress was mitigated. However, oxidative parameter levels were still higher than those of NPD-fed groups. The present study indicates that ingestion of high protein diets could result in an imbalance between oxidant and antioxidant, and thus induce oxidative stress in digestive organs of mice. The oxidative damage was smaller in mice fed with high level of soy protein in comparison with casein.