Direct COVID-19 infection of enterocytes: The role of hypochlorhydria.

COVD-19 disease is characteristically respiratory in nature; however, some patients have gastrointestinal symptoms. These include changes in taste, nausea/vomiting, abdominal pain, and diarrhea. A report has been published of a young patient who repeatedly tested positive in stool samples while nasopharyngeal tests remained negative. This raises doubts about our understanding of the dynamics of COVID-19 disease. The current report describes a need for selective stool testing to explore fecal shedding of viral RNA and presents a hypothesis for direct infection of enterocytes in cases of hypochlorhydria.

Superior growth performance in broiler chicks fed chelated compared to inorganic zinc in presence of elevated dietary copper.

BACKGROUND: The goal of this study was to compare the antagonism of elevated dietary Cu (250 mg/kg) from CuSO4 on three different Zn sources (ZnSO4 · H2O; [Zn bis(-2-hydroxy-4-(methylthio)butanoic acid)], Zn(HMTBa)2, a chelated Zn methionine hydroxy analogue; and Zn-Methionine), as measured using multiple indices of animal performance in ROSS 308 broilers. METHODS: Three experiments were conducted in broiler chicks fed a semi-purified diet. All birds were fed a Zn-deficient diet (8.5 mg/kg diet) for 1 wk, and then provided with the experimental diets for 2 wks. RESULTS: Experiment 1 was a 2 × 2 factorial design with two levels of Cu (8 vs. 250 mg/kg diet from CuSO4) and two Zn sources at 30 mg/kg [ZnSO4 · H2O vs. Zn(HMTBa)2]. Elevated Cu impaired growth performance only in birds fed ZnSO4. Compared to ZnSO4 · H2O, Zn(HMTBa)2 improved feed intake (12 %; P < 0.001) and weight gain (12 %, P < 0.001) and the benefits were more pronounced in the presence of 250 mg/kg diet Cu. Experiment 2 was a dose titration of ZnSO4 · H2O and Zn(HMTBa)2 at 30, 45, 60, and 75 mg/kg diet in the presence of 250 mg/kg CuSO4. Feed:gain was decreased and tibia Zn was increased with increasing Zn levels from 30 to 75 mg/kg. Birds fed Zn(HMTBa)2 consumed more food and gained more weight compared to birds fed ZnSO4, especially at lower supplementation levels (30 and 45 mg/kg; interaction P < 0,05). Experiment 3 compared two organic Zn sources (Zn(HMTBa)2 vs. Zn-Methionine) at 30 mg/kg with or without 250 mg/kg CuSO4. No interactions were observed between Zn sources and Cu levels on performance or tissue mineral concentrations. High dietary Cu decreased weight gain (P < 0.01). Tibia Cu and liver Cu were significantly increased with 250 mg/kg dietary Cu supplementation (P < 0.01). No difference was observed between the two Zn sources. CONCLUSIONS: Dietary 250 mg/kg Cu significantly impaired feed intake and weight gain in birds fed ZnSO4 · H2O, but had less impact in birds fed Zn(HMTBa)2. No difference was observed between the two organic zinc sources. These results are consistent with the hypothesis that chelated organic Zn is better utilized than inorganic zinc in the presence of elevated Cu.

A chicken mRNA similar to heterogeneous nuclear ribonucleoprotein H1.

Heterogeneous nuclear ribonucleoproteins are predominantly nuclear RNA-binding proteins that function in a variety of cellular activities. The objective of these experiments was to clone a cDNA for a chicken protein similar to other previously reported heterogeneous ribonucleoproteins for other species. The 5' and 3' ends of the chicken mRNA were cloned using Rapid Amplification of cDNA Ends (RACE). Subsequently, the expression of the mRNA sequence was confirmed via Northern analysis. The deduced amino acid sequence was approximately 86% identical to corresponding regions of human, mouse, or zebrafish proteins similar to heterogeneous nuclear ribonucleoprotein H1. The expression data confirmed the size of the predicted mRNA sequence. The newly identified sequence may be employed in future studies aimed at understanding the role of heterogeneous nuclear ribonucleoproteins in avian species.

Glyceraldehyde-3-phosphate dehydrogenase expression varies with age and nutrition status.

OBJECTIVE: Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key enzyme in the glycolytic pathway, and it is a popular internal standard for northern blot analysis. We examined GAPDH expression early in life when feed is either provided or not provided to animals. METHODS: Male broiler chickens were provided a standard starter diet plus Oasis nutritional supplement (fed group; Novus International, St. Louis, MO, USA) or no feed (starved group) for the first 3 d posthatch. Subsequently, the standard starter diet was provided to all chickens between 3 and 7 d posthatch. RNA was extracted from the pectoralis thoracicus, and GAPDH expression was evaluated with quantitative northern analysis. RESULTS: GAPDH expression was significantly (P < 0.05) higher in the fed than in the starved group at 3 d posthatch, suggesting that nutritional manipulations can alter GAPDH transcription. Similarly, GAPDH mRNA levels were significantly (P < 0.05) higher at 7 d posthatch compared with all younger animals, suggesting that GAPDH is developmentally upregulated with advancing age. CONCLUSION: GAPDH expression changes with age and nutrition status in the early posthatch chick, suggesting that GAPDH is not a proper internal standard for muscle studies using quantitative northern analysis.

Poly(A)(+) RNA encoding proteins capable of transporting L-methionine and/or DL-2-hydroxy-4-(methylthio) butanoic acid are present in the intestinal mucosa of broilers.

To investigate the presence of poly(A)(+) RNA that encode proteins capable of transporting L-methionine (L-Met) and/or DL-2-hydroxy-4-(methylthio) butanoic acid (HMB), Xenopus oocytes were injected with poly(A)(+) RNA isolated from broiler intestinal mucosa. Healthy oocytes at stage V or VI were collected from Xenopus laevis and microinjected with water, poly(A)(+) RNA or size-fractioned poly(A)(+) RNA. The ability of the injected oocytes to take up either L-Met or HMB was examined by incubating oocytes with [methyl-(3)H]-L-Met or [5-(14)C]-HMB. A greater uptake of L-Met (P < 0.01) and HMB (P < 0.05) by oocytes injected with poly(A)(+) RNA from the duodenum, jejunum and ileum of the small intestine was observed compared with water-injected oocytes. The greatest (P < 0.05) uptake occurred when poly(A)(+) RNA from the jejunum or ileum was injected. Injections from four different pools of sucrose gradient--fractionated poly(A)(+) RNA from all three intestinal segments induced (P < 0.01) L-Met uptake. There were three to four different pools of sucrose gradient--fractionated poly(A)(+) RNA from the duodenum, jejunum and ileum that induced (P < 0.05) HMB uptake. Uptake of HMB was greater at pH 5.5 than at pH 7.5 and was independent of Na(+). Uptake of L-Met induced by all four poly(A)(+) RNA pools decreased dramatically when Na(+) was removed from the uptake buffer, which indicated that the majority of L-Met uptake was Na(+)-dependent. These results indicate that there are multiple sized poly(A)(+) RNA that encode proteins capable of mediated transport of L-Met and/or HMB present in broiler intestinal mucosa.