Observations on carapace color change in the juvenile big-headed turtle (Platysternon megacephalum)

The carapace color of newborn big-headed turtles (Platysternon megacephalum) is polymorphic and usually consists of two phenotypes: yellowish brown and olive green. As the turtles grew, over the first year of life, its carapace gradually turned from yellowish brown to chestnut brown, or from olive green to dark brown, depending on the phenotype. Meanwhile, the turtle’s plastron remained an orange and black pattern and did not change much. In this study, we primarily used HE staining to observe the carapace color change with age in big-headed turtle juveniles. We took the carapace marginal scute tissues twice from the same turtles before and after the carapace color change. Histological observations show that in the marginal scutes of the four tested turtles with different carapace color phenotypes, melanin granules are all concentrated in the dermal layer underneath the dorsal corneous layer, but rarely on the ventral side. Melanin deposits in the dorsal corneous layer were found to increase as the corneous layers thickened, while the melanin deposits in the ventral corneous layer did not change significantly. However, there was no significant difference in melanin deposition in the epidermis and dermis of the carapace among the yellowish brown, chestnut brown, olive green, and dark brown big-headed turtles. The results of our study indicate that the carapace color darkening in big-headed turtles may not be due to changes in melanin content of the carapace, but is the result of melanin accumulation and superposition in the dorsal corneous layer

Purification and Characterization of Recombinant Human Lysozyme from Eggs of Transgenic Chickens.

Transgenic chickens as bioreactors have several advantages, such as the simple establishment procedure, correct glycosylation profile of expressed proteins, etc. Lysozyme is widely used in food industry, livestock farming, and medical field as a replacement of antibiotics because of its antibacterial and complement system-modulating activity. In this study, we used RT-PCR, Western blot, and immunofluorescence to detect the expression of recombinant human lysozyme (rhLY) in the transgenic chicken. We demonstrated that the transgene of rhLY was genetically stable across different generations. We next optimized the purification procedure of rhLY from the transgenic eggs by utilizing two steps of cation-exchange chromatography and one gel-filtration chromatography. About 6 mg rhLY with the purity exceeding 90% was obtained from ten eggs, and the purification efficiency was about 75%. The purified rhLY had similar physicochemical and biological properties in molecular mass and antibacterial activity compared to the commercial human lysozyme. Additionally, both of them exhibited thermal stability at 60°C and tolerated an extensive pH range of 2 to 11. In conclusion, our study proved that the transgenic chickens we have previously generated were genetically stable and suitable for the production of active rhLY. We also provided a pipeline for purifying the recombinant proteins from transgenic eggs, which could be useful for other studies

Effect of incubation temperature and substrate moisture on embryonic development, hatchling phenotypes and post-hatching growth in the Reeves’ Turtle, Mauremys reevesii

Background Reeves’ Turtles (Mauremys reevesii) are economically important in aquaculture in China. Understanding the effects of incubation temperature and substrate moisture on embryos and hatchlings is of great significance for improving the artificial culture of M. reevesii. However, available studies have not yet determined the thermal and hydric optima for M. reevesii eggs, and the potential interaction between the two factors. Methods In this study, eggs of M. reevesii were incubated at five temperature levels (23, 26, 29, 32 and 35 °C, fluctuation range ± 0.5 °C). In each temperature level, there were three substrate moisture levels (1:0.5, 1:0.9 and 1:1.2, weight ratio of vermiculite to water). Thus, a total of 15 combinations of temperature and moisture were used to examine the effects of incubation temperature and substrate moisture on incubation duration, hatching success, hatchling phenotypes, post-hatching growth and hatchling survival. Results Substrate moisture did not significantly affect most development parameters (except incubation duration and carapace width of hatchlings). Eggs incubated at low moisture level (1:0.5) had a longer incubation duration and produced hatchlings with smaller carapace widths than those incubated at medium (1:0.9) or high (1:1.2) moisture levels. Incubation temperature had a significant effect on incubation duration, hatching success, hatchling phenotypes and hatchling survival. Incubation duration decreased as incubation temperature increased. Eggs incubated at 23, 26 and 29 °C showed higher hatching success than those incubated at 32 and 35 °C. Hatchlings incubated at 32 °C were smaller in body size and mass than those incubated at 23, 26 and 29 °C. At 12 months of age, incubation temperature had no long-lasting effect on body mass, but hatchlings incubated at 23 and 35 °C had lower survival rates than those incubated at 26, 29 and 32 °C. For the development of embryos and hatchlings, the interaction between incubation temperature and substrate moisture was not significant. Conclusions Our results indicate that incubation temperature has a significant influence on the development of embryos and hatchlings of M. reevesii, while substrate moisture only significantly affects the incubation duration and carapace width of hatchlings. The combination of an incubation temperature of 29 ± 0.5 °C and a substrate moisture level of 1:1.2 represented optimal incubation conditions in this experiment. Such incubation conditions are helpful in obtaining higher hatching success, shorter incubation duration and higher survival rates for this aquaculture species

Effects of the Chemical Structure, Surface, and Micropore Properties of Activated and Oxidized Black Carbon on the Sorption and Desorption of Phenanthrene

The effects of the chemical structure, surface properties, and micropore of modified black carbon samples (BCs) on the sorption mechanism of hydrophobic organic contaminants (HOCs) are discussed. Activated and oxidized BCs were produced from a shale kerogen at 250-500 degrees C by chemical activation regents (KOH and ZnCl2) and then by oxidative regents (H2O2 and NaClO). The surface properties (water contact angel, Boehm titration, and cation exchange capacity, CEC), structural properties (advanced solid-state C-13 NMR), micropore properties (CO2 adsorption), mesopore properties (N-2 adsorption), and sorption and desorption properties of phenanthrene were obtained. The results showed that ZnCl2-activated BCs had higher basic surface groups, CEC values, aromatic carbon contents, micropore volumes, and adsorption volumes but exhibited lower acidic surface groups than the KOH-activated BCs did. Micropore modeling and sorption irreversibility indicated that the micropore filling was the main sorption mechanism of phenanthrene. In addition, ZnCl2 activated and NaClO oxidized BCs showed a nice regression equation between adsorption volumes and micropore volumes (CO2-V-0) as follows: Q(0)' = 0.495V(0) + 6.28(R-2 = 0.98, p < 0.001). Moreover, the contents of nonprotonated aromatic carbon, micropore volumes, and micropore sizes are the critical factors to micropore filling mechanism of phenanthrene on BCs. The size of fused aromatic rings was estimated from the recoupled H-1-C-13 dipolar dephasing, and the BC structural models at temperatures ranging from 300 to 500 were proposed. This finding improves our understanding of the sorption mechanism of HOCs from the perspectives of chemical structure and micropore properties

MicroRNA ame-let-7 targets Amdop2 to increase sucrose sensitivity in honey bees (Apis mellifera)

Abstract Background As an important catecholamine neurotransmitter in invertebrates and vertebrates, dopamine plays multiple roles in the life of the honey bee. Dopamine receptors (DA), which specifically bind to dopamine to activate downstream cascades, have been reported to be involved in honey bee reproduction, division of labour, as well as learning and motor behaviour. However, how dopamine receptors regulate honey bee behavior remains uninvestigated. Results The expression level of Amdop2 in the brain increased with the age of worker bees, which was just the opposite trend of ame-let-7. Inhibition of ame-let-7 through feeding an inhibitor upregulated Amdop2 expression; conversely, overexpression of ame-let-7 through a mimic downregulated Amdop2. Moreover, knockdown of Amdop2 in forager brain led to significantly higher sucrose responsiveness, which is similar to the phenotype of overexpression of ame-let-7. Finally, we confirmed that ame-let-7 directly targets Amdop2 in vitro by a luciferase reporter assay. Conclusions ame-let-7 is involved in the dopamine receptor signaling pathway to modulate the sucrose sensitivity in honey bees. Specifically, it down-regulates Amdop2, which then induces higher responses to sucrose. These results further unraveled the diverse mechanisms of the dopamine pathway in the regulation of insect behavior

Optimal conditions of purified rhLY and hLY for their antibacterial activity.

<p>(A) The optimal temperatures of the rhLY and hLY against <i>M</i>. <i>lysodeikticus</i> were measured in phosphate buffered saline (pH 7.18) at 25°C, 40°C, 60°C, and 80°C respectively. (B) The optimal pH values of the rhLY and hLY for the antibacterial activity was measured in phosphate buffer with different pH values (from 2–12), separately. hLY, commercial hLY; rhLY, purified rhLY. The experiment for each group was repeated at least three times, and the results were presented as mean ± S.D.</p

Immunofluorescence detection of hLY expression in oviduct sections.

<p>Sections of the magnum portions of the oviducts from a G3, a G4, and a wild type White Leghorn hen were immunolabeled with the anti-hLY antibody (red). The nuclei were stained with DAPI (blue). Scale bar: 25 μm.</p

Stability of purified rhLY and hLY under different pH conditions.

<p>The lysozyme was incubated in phosphate buffer of different pH values (from 2–12) for 20 minutes. Then the antibacterial activity against <i>M</i>. <i>lysodeikticus</i> was measured in phosphate buffered saline (pH 7.18) at room temperature. The lysozyme activity incubated in phosphate buffer at pH 7 was defined as 100% activity. hLY, commercial hLY; rhLY, purified rhLY. The experiment for each group was repeated at least three times, and the results were presented as mean ± S.D.</p

Expression of rHLY in transgenic chickens.

<p>(A) RT-PCR analysis of the expression of rhLY in G3 and G4 hens. Total RNA was isolated from the heart, liver, spleen, lung, kidney, intestine and oviduct of the G3 and G4 hens. NC (negative control) was the RNA of the oviduct from a non-transgenic hen. The 460bp fragments represented the RT-PCR products of hLY, and the 81bp fragments represented the RT-PCR products of GAPDH. M, DNA ladder. (B) Western blot of egg whites from a G3, a G4 and a non-transgenic hen (NC). Samples were separated by SDS-PAGE and hybridized with anti-hLY antibody and anti-cLY antibody, separately. hLY, commercial hLY (positive control for anti-hLY); cLY, commercial cLY (positive control of anti-cLY).</p

Antibacterial activity of rhLY, hLY, and cLY against <i>M</i>. <i>lysodeikticus</i>.

<p>The picture showed the inhibition zones of the agar disc diffusion of commercial hLY (A), commercial cLY (B), purified rhLY (C), and sterile water (D, negative control).</p