Mohammad-Borhan Al-Zghoul

Kv11.1 Channel Subunit Composition Includes MinK and Varies Developmentally in Mouse Cardiac Muscle

The Kv11.1 (also ERG1) K+ channel underlies cardiac IKr, a current that contributes to repolarization in mammalian heart. In mice, IKr current density decreases with development and studies suggest that changes in the structure and/or properties of the heteromultimeric IKr/Kv11.1 channel are responsible. Here, using immunohistochemistry, we report that total Kv11.1 α subunit protein is more abundant in neonatal heart and is distributed throughout both adult and neonatal ventricles with greater abundance in epicardia. Immunoblots reveal that the α subunit alternative splice variant, Kv11.1a, is more abundant in adult heart while the Kv11.1b variant is more abundant in neonatal heart. Additionally, MinK channel subunit protein is shown to co‐assemble with Kv11.1 protein and is more abundant in neonatal heart. In summary, Kv11.1/IKr channel composition varies developmentally and the higher IKr current density in neonatal heart is likely attributable to higher abundance of Kv11.1/IKr channels, more specifically, the Kv11.1b splice variant. Developmental Dynamics 237:2430–2437, 2008.

Distribution and density of mast cells in camel small intestine and influence of fixation techniques

This study was carried out to gather species-specific data on mast-cell density and distribution in camel small intestine under different fixation conditions and to elucidate the presence and cross-reactivity of tryptase in the camel small intestine using human specific anti-tryptase antibody. Tissue specimens from the jejunum, duodenum, and ileum were obtained from 9 healthy, 9-12 months old, male camels. Specimens were fixed either with carnoys fluid or formalinbuffered solution and stained with either methylene blue or immunohistochemically to identify mast cells. The present study demonstrated for the first time, the presence and cross-reactivity of tryptase in the camel small intestine using a specific mouse anti-human tryptase antibody. Mast cells were detected in all histological layers of the camel small intestine (mucosal, submucosal, muscularis externa and serosa). Among all locations examined in the duodenum, ileum and jejunum, no significant difference was observed in mast-cell counts among the lamina propria, muscularis mucosae, muscularis externa and the serosa. The only significant difference observed was the mast-cell count in submucosa region where the highest and lowest mast count was observed in the jejenual and ileal submucosa, respectively. Significant differences regarding the distribution of mast cell as well as the influence of the fixation method could be observed. This underlines the fact that data regarding mast cell heterogeneity from other species, obtained by different fixation methods, are not comparable. This fact has to be taken into account when evaluating mast cell subtypes under pathological conditions.

Characterization of male reproductive anatomy of the endangered Arabian oryx (Oryx leucoryx)

Reproductive tracts of four male Arabian oryx (Oryx leucoryx) from Shaumari Nature Reserve in Jordan were examined to characterize their reproductive anatomy. Animals were allocated into two groups based on their age: Group 1 (n = 2, males were 12 and 14 mo old) and Group 2 (n = 2, males were 7 and 9 yrs old). Observations regarding the morphology, position and orientation of different reproductive organs were made. The external and internal genital organs of male oryx were similar to other domestic ruminant species with minor differences.

Thermal manipulation during broiler chicken embryogenesis increases basal mRNA levels and alters production dynamics of heat shock proteins 70 and 60 and heat shock factors 3 and 4 during thermal stress

This study investigated the effects of thermal manipulation (TM) during embryonic days 12 to 18 on the cloacal temperature (Tc) and the kinetics of muscle mRNA levels of heat shock proteins 70 and 60 (Hsp70 and Hsp60) and heat shock factors 3 and 4 (HSF3 and HSF4) during the first week of life and during thermal stress (TS). One thousand five hundred fertile chicken eggs were randomly divided into 5 groups: control group (37.8°C), TM1 (38.5°C for 18 h), TM2 (39°C for 18 h), TM3 (39.5°C for 18 h), and TM4 (40°C for 18 h). On post-hatch days 14 and 28 of age, 30 randomly selected chicks from each group were thermally stressed at 41.0°C for 6 h, while another 30 randomly selected chicks from each group were kept under thermo-neutral conditions. The Tc of TM chicks was only numerically lower than that of the control during the study period. However, during TS at days 14 and 28 of age, the Tc of TM chicks was significantly lower than that of the controls. On post-hatch days 14 and 28, the basal mRNA levels of Hsps and HSFs were significantly higher than those of the control. Furthermore, during TS, rapid increases in the mRNA levels of Hsps and HSFs in the TM groups were observed. These results indicate that, as well as altering their basal mRNA levels during the first week post-hatch, TM also altered the dynamics of the mRNA expression of HSPs and HSFs, which was associated with improved acquisition of thermotolerance during TS.

Effect of thermal manipulation of broilers embryos on the response to heat-induced oxidative stress

ABSTRACT Effects of embryonic thermal manipulation (TM) on mRNA expressional levels and total antioxidant capacity of genes associated with heat‐induced oxidative stress (NOX4, GpX2, SOD2, catalase, and AvUCP) in 2 breeds of broiler chicken were investigated. Fertile Cobb and Hubbard eggs (n = 1,200) were divided into 4 treatment groups: Cobb control, Cobb TM, Hubbard control, and Hubbard TM. Control groups were maintained under standard conditions (37.8°C; 56% relative humidity), whereas TM groups were incubated at 39°C and 65% relative humidity for 18 h a day from embryonic days (ED) 10 to 18. On post‐hatch day 28, the broilers were subject to acute heat stress (AHS) at 40°C for 7 h. At certain intervals (0, 1, 3, 5, and 7 h), 12 chickens from each of the 4 groups were humanely euthanized, and liver samples were immediately isolated. During AHS, in both breeds, the mRNA expression levels of NOX4, GPx2, SOD2, and catalase in TM chickens were significantly lower than in controls, but AvUCP mRNA expression in the TM group was higher. The total antioxidant capacity and activity of superoxidase dismutase and catalase were significantly lower in the TM than in the control group in both breeds. The results of this study suggest that TM has a long‐lasting effect on the acquisition of thermotolerance in 2 broiler chicken breeds as indicated by the reduction of system genes associated with heat‐induced oxidative stress.

Thermal Manipulation Mid-term Broiler Chicken Embryogenesis: Effect on Muscle Growth Factors and Muscle Marker Genes

ABSTRACT Thermal manipulation (TM) during broiler chicken embryogenesis has been shown to promote muscle development and growth. However, the molecular bases of promoting broiler muscle development and growth are not fully understood. The aim of this study was to investigate the molecular bases of muscle growth and development in broiler chickens subjected to TM. This included the investigating of the changes in mRNA expression levels of muscle marker genes, namely MyoD, myogenin, paired box transcription factor (Pax7) and proliferating cell nuclear antigen (PCNA), and muscle growth factors namely insulin-like growth factor 1 (IGF-1), myostatin and growth hormone (GH) during embryogenesis and on posthatch days 10 and 28. Fertile Cobb eggs (n=1500) were divided into four groups. Eggs in the first group (control) were incubated at 37.8°C and 56% RH, whereas, eggs in the second group (TM 1 ) , third group (TM 2 ) , and fourth group (TM 3 ) were subjected to 39 oC and 65% RH daily during embryonic days (ED) 12–18 for 9, 12, and 18 hours, respectively. Body weight (BW) during embryogenesis and posthatch days (1, 3, 5, 7, 14, 21, 28 and 35) was recorded. mRNA expression levels of muscle marker genes and muscle growth factor genes during ED 12, 14, 16 and 18 and on posthatch days 10 and 28 were analyzed using real-time RT-PCR. TM upregulated the mRNA expressions of muscle marker and growth factors genes. This upregulation was accompanied by improvement of body weight near and at market age.