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Biomedical subjects

Tao Bo

Publications and source records attributed to Tao Bo.

At least 19 recordsLinked to original sources

[Long-term effects of neonatal recurrent seizures on gamma-aminobutyric acid A receptor alpha1 and gamma2 subunit expressions in the rat brain].

OBJECTIVE: To investigate the long-term effects of flurothyl-induced neonatal recurrent seizures on GABA A receptor (GABA(A)R) alpha1 and gamma2 subunit expressions in adult rat brain, and discuss the relationship between these alterations of GABA(A)R subunits in mature brain and the changes of spatial memory and seizure susceptibility in adult rats. METHODS: Thirty-two of 7-day-old (P7) Sprague-Dawley rats were divided randomly into two groups: the control group and the seizure group. Seizures were induced by inhalant flurothyl daily for six consecutive days. Rats were tested for spatial memory by using the Morris water maze task from postnatal 61 d(P61) to P65. Seizure threshold was examined by intraperitoneal injection of pentylenetetrazol, and then the brains were sampled on P75. The expressions of GABA(A)R alpha1 and gamma2 subunits mRNA and protein in cerebral cortex and hippocampus were detected by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry method. RESULTS: On P64, the escape latencies in water maze for the rats in the seizure group were significantly longer than those of the control rats [(82 424+/-35 622)ms vs (40 712+/-29 468)ms, P=0.001]. On P65, the frequency of crossing target within 120 s in water maze for the rats in the seizure group were significantly less than those of the control rats [(1.2+/-0.9) vs (3.1+/-1.3), P<0.001]. There was no difference in seizure threshold between the two groups on P75 [(1 487+/-662)s vs (1 841+/-648)s, P=0.137]. Compared to the control rats, the accumulated optical density (AOD) of GABA(A)R alpha1 subunit immunoreactivity in seizure rats decreased significantly in the parietal cortex, CA1-2 and CA4 region (P<0.05). The AOD of alpha1 subunit protein immunoreactivity in the frontal cortex, CA3 and dentate gyrus (DG) were of no significant difference between the two groups on P75 (P>0.05). There were also no differences in the AOD of gamma2 subunit protein immunoreactivity in the parietal lobe, DG, and CA1-3 region between the two groups (P>0.05). The AOD of gamma2 subunit protein immunoreactivity in the frontal lobe and CA4 region decreased significantly in the seizure group than those in the control group (P<0.05). The expressions of alpha1 subunits mRNA in the cerebral cortex and gamma2 subunit mRNA in the hippocampus were similar between the two groups (P>0.05), but the expressions of alpha1 subunits mRNA in the hippocampus and gamma2 subunit mRNA in the cerebral cortex in the seizure group decreased significantly as compared with those in the control group (P< 0.05). CONCLUSION: Recurrent seizures in neonatal rats modify GABA(A) receptor alpha1 and gamma2 subunits expression in the cerebral cortex and hippocampus of adult rats, and cause long-term cognitive deficit, Which suggests that abnormal GABA(A) receptor expression might play an important role in long-term cognitive deficit induced by early life recurrent seizures.

Animals↗

Long-term effect of early discharge on sEPSC and [Ca2+]i in developing neurons.

To study the long-term changes induced in immature rat cortical neuronal cultures by transient exposure to an Mg(2+)-free treatment, at cultured day 6, cells were assigned into three groups, based on the mediums they were transiently exposed to as follows: control group 1 (CONT1) was exposed to Dulbecco's Modified Eagle's Medium (DMEM), control group 2 was exposed to a physiological solution (PS), and the magnesium-free physiological solution group (MGFPS) was exposed to the same medium as CONT2 except for the removal of magnesium. Following a 3-h exposure, the amplitude and frequency of spontaneous excitatory postsynaptic currents (sEPSC) were recorded and intracellular calcium concentrations ([Ca2+]i) were measured. Compared to the CONT1 and CONT2 groups, the MGFPS group displayed a significantly greater amplitude (at d6, d7, d9, and d12) and frequency (at d6, d7, and d9) of sEPSC (p<0.05). Also, both the resting and peak intracellular calcium levels were significantly greater in the MGFPS group at days 6, 7, 9, 12 and 17 (p<0.05). The rise time (time from resting level to peak level of intracellular calcium following NMDA application) was significantly shorter in the MGFPS group at culture days 7 and 17 and significantly longer at culture day 12 (p<0.05). Finally, we compared the percentage of cortical neurons expressing neuron-specific enolase (NSE) and found that there were no significant differences in the number of NSE positive neurons among three groups at days 7, 12, and 17. Our results suggests that there are long-term changes in sEPSCs and [Ca2+]i in cultured rat cortical neurons following exposure to Mg2+-free environment without cell loss.

Analysis of Variance↗

Dynamic process of phospholipid-protein interaction studied by capillary isoelectric focusing with whole-column imaging detection.

Liposomes are vesicles formed by the aggregation of amphiphilic phospholipid molecules, which can mimic natural cell membranes. Interaction between liposome and protein is important for the structure and function of natural cell membranes. In this study, a CIEF method with whole-column imaging detection was developed for monitoring the dynamic process of phospholipid-protein interactions. The CIEF profiles at successive interaction times clearly displayed the formation of the different conjugates between phospholipid and protein at different stages. Due to the diversity of the chemical and physical properties of targeted proteins in this study (trypsin inhibitor, beta-lactoglobulin B, phosphorylase b, and trypsinogen), different dynamic processes of phospholipid-protein interactions were exhibited. The type of phospholipids played an important role in the dynamic process of phospholipid-protein interaction, as noted by the use of zwitterionic phospholipid (phosphatidylcholine) and acidic phospholipid (phosphatidylserine). Mechanisms involved in these interactions were discussed by monitoring the dynamic processes in this study.

Electrophoresis, Capillary↗

Immobilization of phospholipid-avidin on fused-silica capillaries for chiral separation in open-tubular capillary electrochromatography.

Phospholipid-coated fused-silica capillaries with immobilized avidin were applied in the chiral separation of D,L-tryptophan, D,L-PTH-serine, and D,L-PTH-threonine at pH 7.4 by open-tubular CEC. Liposomes prepared from 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(Cap biotinyl), or 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(Biotinyl) with different amounts of phosphatidylserine were assessed as phospholipid coating materials. The stability of the coating and the success of the coating procedure were evaluated in terms of the repeatability of the enantiomer migration times and the resolution of enantiomers. The coating procedure itself significantly affected the migration times and resolution of the enantiomers. Reliable chiral separations with high separation efficiencies were achieved through careful choice of the coating method.

Adsorption↗

Protein thermal stability and phospholipid-protein interaction investigated by capillary isoelectric focusing with whole column imaging detection.

CIEF with whole column imaging detection (WCID) is an attractive technique for studying protein reaction and protein-ligand interaction due to its fast separation, simple operation, and high efficiency. In this study, two interesting applications by the CIEF-WCID were developed, involving the study of protein thermal stability and phospholipid-protein interaction. Four proteins (beta-lactoglobulin B, trypsin inhibitor, phosphorylase b, and trypsinogen) with different pI, and two types of phospholipids, including phosphatidylcholine (PC) and phosphatidylserine (PS), were used for this purpose. First, the altered CIEF profiles of four proteins were exhibited due to conformational changes resulting from protein denaturation induced by a high incubation temperature at 60 degrees C. It was demonstrated that the addition of a zwitterionic phospholipid (PC) played a crucial role in the thermal stability of targeted proteins, especially for trypsin inhibitor whose thermal stability was promoted with the addition of the PC vesicles at 60 degrees C. Second, the zwitterionic (PC) and acidic (PS) phospholipids displayed completely different interactions with the proteins. The addition of PS vesicles modified the zwitterionic phospholipids to carry negative charges, which correspondingly changed the interaction between the phospholipid and the protein. Our study demonstrates that the CIEF-WCID is a powerful approach to study protein reaction and protein-ligand interaction with high efficiency, high selectivity, and fast separation.

Chromatography↗

[Role of caspase-1 and cytokines activated by caspase-1 in brain injury of the developing rats following recurrent seizures].

OBJECTIVE: The expressions of caspase-1 and cytokines activated by caspase-1 are associated with the pathophysiology of many diseases for its proinflammatory and proapototic peculiarity. However its relationship to brain injury of developing rats following recurrent seizures has not yet been identified. This study aimed to investigate the role of caspase-1 and cytokines activated by caspase-1 in brain injury of developing rats following recurrent seizures. METHODS: A total of 96 postnatal 20 day Sprague-Dawley rats were randomly assigned into Control and Seizure groups. Seizures were induced in the Seizure group by flurothyl inhalation daily for six days. Brain tissues were sampled at 6 hrs, and at 1, 3, and 7 days after last seizure. The expressions of caspase-1, interleukin (IL)-18 and IL-1beta mRNA in the cerebral cortex were detected by RT-PCR. The water content of the brain and the pathological changes of cortex nerve cells were observed. Brain injury was evaluated using a semiquantitative neuropathological scoring system. RESULTS: The levels of caspase-1 and IL-18 mRNA in the cerebral cortex of the Seizure group were obviously higher than those in the Control group at 6 hrs, and at 1, 3, and 7 days after seizure (P < 0.05 or P < 0.01). The expression of IL-1beta mRNA in the Seizure group exhibited a biphasic pattern: increased significantly at 6 hrs, and at 1 and 7 days post-seizure (P < 0.01), but was not significantly different from the Control group at 3 days post-seizure. Edema, degeneration and necrosis of nerve cells in cerebral cortex, accompanying by inflammatory cell infiltration and apoptosis of nerve cells, were observed under a light microscope in the Seizure group after recurrent seizures. The water content of the brain in the Seizure group increased significantly compared with that in the Control group at 6 hrs, and at 1 and 3 days after recurrent seizures (P < 0.01). The Seizure group had significantly higher neuropathological scores than the Control group at each time point (P < 0.01). CONCLUSIONS: Caspase-1 and cytokines activated by caspase-1 play an important role in the developing brain injury after recurrent seizures.

Animals↗

[Effects of neonatal recurrent seizures on gamma-aminobutyric acid B1 receptor expression in the rat brain].

OBJECTIVE: This study investigated the effects of flurothyl-induced neonatal recurrent seizures on gamma-aminobutyric acid B1 receptor (GABAB1R) expression in neonatal and adult rat brain, and explored the possible relationship between the alterations of GABAB1R in mature brain and the changes of spatial memory and seizure susceptibility in adult rats. METHODS: Forty-eight postnatal day (P) 7 Sprague-Dawley rats were randomly assigned into two groups: Control and Seizure group (n=24 each). Seizures were induced by inhalant flurothyl daily for six consecutive days in rat pups from the Seizure group. Twelve rats selected randomly in each group were sacrificed on the 7th day after the last seizure for detecting the expressions of GABAB1R mRNA and protein in cerebral cortex and hippocampus by reverse transcription-polymerase chain reaction (RT-PCR) and immuno-histochemistry method. The spatial memory was tested by using the Morris water maze task during P61 to P64 and the seizure threshold was measured at P75 following intraperitoneal injection of pentylenetetrazol ( PTZ ) in the remaining rats. The rats were then sacrificed for detecting the expressions of GABAB1R mRNA and protein in cerebral cortex and hippocampus. RESULTS: The expressions of GABAB1R mRNA and protein in the cerebral cortex on the 7th day after the last seizure and at P75 decreased significantly in the Seizure group when compared with the Control group (P < 0.05). The GABAB1R protein expression in the dentate gyrus on the 7th day after the last seizure in the Seizure group was significantly lower than that in the Control group (P < 0.05), but the GABAB1R mRNA expression in the hippocampus was not different from that in the Control group. There were no significant differences in the expressions of GABAB1R mRNA and protein in the hippocampus between the two groups at P75. The escape latencies in water maze of the rats in the Seizure group at P64 were significantly longer than those in the Control group (98,533.8 +/- 27,205.4 ms vs 46,723.3 +/- 40,666.5 ms; P <0.05). There were no differences in the seizure threshold between the two groups. CONCLUSIONS: The expressions of GABAB1R mRNA and protein in the cerebral cortex and hippocampus of neonatal rats with recurrent seizures decreased significantly, suggesting the changes of GABAB1R may be related to acute brain injury following neonatal recurrent seizures and the memory deficit in adult rats caused by neonatal recurrent seizures.

Animals↗

Characterization of phospholipid-protein interactions by capillary isoelectric focusing with whole-column imaging detection.

The integration of functional proteins in the phospholipid bilayer is one of the most crucial features of biological membrane architecture. Phospholipid-protein interactions play an important role in the functions of bounded proteins in the phospholipid membrane. When the phospholipid-protein interactions occur, the protein structure tends to alter, which can result in a change in the isoelectric points (pI) of protein. Capillary isoelectric focusing (cIEF) with whole-column imaging detection (WCID) is an attractive technique that has the features of simple operation, high resolution, and fast separation without focused band mobility for detection of amphoteric biomolecules. In this study, a cIEF-WCID method was developed to characterize the phospholipids-protein interactions by monitoring the protein cIEF profiles. Seven proteins with different pI and molecular mass , and a zwitterionic phosphatidylcholine (PC) with zwitterionic properties, were used to evaluate the feasibility of the cIEF-WCID approach in the study of phospholipid-protein interactions. The cIEF profiles changed in response to the changes in protein conformation, clearly exhibiting interactions between the PC vesicles and the targeted proteins. The formation of PC-protein complex was observed in the cIEF electropherograms. It was demonstrated that seven proteins displayed distinct interactions with the PC vesicles due to their different chemical and physical properties. The influences of the PC concentration, incubation time, and incubation temperature on the phospholipids-protein interactions were investigated. This study validated a novel analytical approach for the characterization of phospholipid-protein interactions.

Animals↗

Characterization of bovine serum albumin-tryptophan interaction by capillary isoelectric focusing with whole column imaging detection.

Capillary isoelectric focusing (cIEF) with whole column imaging detection (WCID) was explored for the characterization of bovine serum albumin (BSA)-tryptophan interaction, to further understand protein-drug interactions. The BSA-tryptophan interaction was dynamically monitored by cIEF-WCID, to provide the cIEF profiles of the BSA-tryptophan interaction system at different focusing times. Our study demonstrated that the cIEF behavior of BSA can serve as a probe into the study of BSA-tryptophan interaction, through monitoring the change in its cIEF profile when the interaction occurred. The study illustrated that the BSA peak split due to the BSA-tryptophan interaction, and the peak of BSA-tryptophan complex was clearly identified in the cIEF electropherograms. By comparing the cIEF profiles of BSA/L-tryptophan and BSA/D-tryptophan, respectively, our study demonstrated that BSA interacted with the enantiomers of tryptophan with a chiral recognition. L-Tryptophan demonstrated a very strong interaction with BSA, while D-tryptophan exhibited a much weaker interaction with BSA. The effects of the BSA concentration, the tryptophan concentration, the focusing time and the incubation time on the BSA-tryptophan interaction were investigated. This study offers a novel approach for the study of protein-drug interactions.

Animals↗

c-Fos, N-methyl-d-aspartate receptor 2C, GABA-A-alpha1 immonoreactivity, seizure latency and neuronal injury following single or recurrent neonatal seizures in hippocampus of Wistar rat.

To evaluate the long-term effects of single or recurrent prolonged neonatal seizures on seizure threshold and neuronal activity in the brain, a novel "twist" seizure was induced by coupling early-life flurothyl-induced seizures with later exposure to pentylenetetrazol. The authors assigned six neonatal rats for each group: the single-seizure group (SS), the recurrent-seizure group (RS) and the control group. At postnatal day 46, seizure threshold was examined using pentylenetetrazol, and then the brain slices were evaluated with thionine staining, in situ end labeling and immunohistochemical studies. The Results showed that the rats in SS and RS groups all had reduced latencies to develop generalized tonic seizures induced by PTZ compared with controls (P<0.01). Morphologic changes, cell loss and apoptotic cells were observed only in those of RS group. Significant fos and NR2C-immunoreactive positive cells were seen in hippocampus of rats in both SS and RS groups compared with controls (P<0.01). A significant decrease in the number of GABA-A-alpha1 immunoreactive positive neurons was detected in hippocampus in rats of SS and RS groups compared with the controls (P<0.01). We conclude that neonatal rats subjected to prolonged seizures have pronounced long-term effects on seizure threshold and neuronal neurophysiological activity in the brain. Obvious neuronal injury, however, was only seen in rat with recurrent-seizures. Subtle brain damage might occur in rats experiencing single prolonged neonatal seizures.

Animals↗

A method for filling in the cohesive ends of double-stranded DNA using Pfu DNA polymerase.

The present paper reports a highly efficient method of making blunt ends from cohesive ends of double-stranded DNA. Klenow fragment and Pfu DNA polymerases were used to fill in the cohesive ends. Since the transformation efficiency can directly reflect the filling-in efficiency, similar ligation and transformation conditions were used, and the filling-in efficiency was compared with the corresponding transformation efficiency. The results indicate that the filling-in efficiency of Pfu DNA polymerase was 1.96 times that of Klenow fragment and its efficiency was markedly higher than that of Klenow fragment (P<0.01). The optimization experiments on reaction conditions indicate, when the pH is 8.5 and the temperature is 74 degrees C, that the filling-in efficiency was highest upon using a buffer containing 3 mM MgSO4 and 300 microM dNTP.

Buffers↗

Determination of dissociation constants of pharmacologically active xanthones by capillary zone electrophoresis with diode array detection.

In this article, the dissociation constants (pKa) of 10 pharmacologically active xanthones isolated from herbal medicine Securidaca inappendiculata were determined by capillary zone electrophoresis with diode array detection. The pKa values determined by the method based on the electrophoretic mobilities (calculated from migration times) have been proved by the method based on UV absorbance calculated from the online spectra corresponding peaks. No conspicuous difference was observed between the two methods with acceptable reproducibility. Two pKa values (pKa1 and pKa2) were found for four xanthones while generally the 10 compounds possess the pKa values ranging from 6.4 to 9.2.

Electrophoresis, Capillary↗

Separation methods for pharmacologically active xanthones.

Xanthones, as a kind of polyphenolic natural products with many strong bioactivities, are attractive for separation scientists due to the similarity and diversity of their structures resulting in difficult separation by chromatographic methods. High performance liquid chromatography (HPLC) and thin layer chromatography (TLC) are traditional methods to separate xanthones. Recently, capillary electrophoresis (CE), as a micro-column technique driven by electroosmotic flow (EOF), with its high efficiency and high-speed separation, has been employed to separate xanthones and determine their physicochemical properties such as binding constants with cyclodextrin (CD) and ionization constants. Since xanthones have been used in clinic treatment, the development of chromatographic and CE methods for the separation and determination of xanthones plays an essential role in the quality control of some herbal medicines containing xanthones. This article reviewed the separation of xanthones by HPLC, TLC and CE, citing 72 literatures. This review focused on the CE separation for xanthones due to its unique advantages compared to chromatographic methods. The comparison of separation selectivity of different CE modes including capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC), microemulsion electrokinetic capillary chromatography (MEEKC) and capillary electrochromatography (CEC) was discussed. Compared with traditional chromatographic methods such as HPLC and TLC, CE has higher separation efficiency, faster separation, lower cost and more flexible modes. However, because of low sensitivity of UV detector and low contents of xanthones in herbal medicines, CE methods have seldom been applied to the analysis of real samples although CE showed great potential for xanthone separation. The determination of xanthones in herbal medicines has been often achieved by HPLC. Hence, how to enhance CE detection sensitivity for real sample analysis, e.g. by on-line preconcentration and CE-MS, would be a key to achieve the quantitation of xanthones.

Chromatography↗

Long-term effects of neonatal seizures on subsequent N-methyl-D-aspartate receptor-1 and gamma-aminobutyric acid receptor A-alpha 1 receptor expression in hippocampus of the Wistar rat.

To evaluate the pathophysiological mechanism of subsequent reduced seizure threshold following neonatal seizures, single or recurrent prolonged seizures were induced to neonatal rats by the inhalant flurothyl. The expression of N-methyl-d-aspartate receptor 1 (NR1) and gamma-aminobutyric acid receptor A-alpha 1 (GABA-A-alpha 1) immunoreactivity in hippocampus were examined by Western blotting analysis at the day 7 (P7) and day 75 (P75) after the last seizure. Whereas there were no significant changes in single seizure group and recurrent seizure group of P75, NR1 expression enhanced significantly in P7 rats of recurrent seizure group. Meanwhile, polypeptide levels of GABA-A-alpha 1 receptor subunit decreased significantly in both single and recurrent seizure-treated P7 and P75 rats. Our results suggest that recurrent or single prolonged seizures during the neonatal period may have long-term effects on the balance between excitatory NMDA system and inhibitory GABA system in hippocampus of rats.

Animals↗

Long-term effects of seizures in neonatal rats on spatial learning ability and N-methyl-D-aspartate receptor expression in the brain.

For the purpose of investigating the long-term effects of seizures in neonatal rats on spatial learning ability and N-methyl-D-aspartate (NMDA) receptor expression in adult rat brain, a seizure was induced by inhalant flurothyl daily in neonatal Wistar rats from postnatal day 6 (P6). The authors assigned six rats each averagely into the single-seizure group, the recurrent-seizure group (seizures induced in six consecutive days), and the control group. During P60 to P65, the rats were tested for spatial learning ability with the Morris water maze task. On P75, the authors examined protein expression of the NMDA receptor (NR) subunits, NR1, 2A, 2B, 2C, and 2D, in the cerebral cortex and hippocampus by Western blotting analysis. On P65, the escape latencies from the water maze of the rats in the recurrent-seizure group were significantly longer than those of the control rats, but there was no difference between the single-seizure group and the control group. NR subunit expression in the cerebral cortex and hippocampus of the rats with single seizure was similar to those in the control rats. Compared with the control rats, the protein expressions of NR1, NR2A and NR2B in the cerebral cortex and NR2A in the hippocampus of the recurrent-seizure group was significantly decreased, but NR2C protein expression in the cerebral cortex and hippocampus significantly increased. Recurrent seizures induced in neonatal rats might cause long-term spatial learning ability deficit and modify NR expression in the cerebral cortex and hippocampus of adult rats. The results suggest that abnormal NR expression might play an important role in long-term spatial learning ability deficit induced by recurrent seizures in early life.

Animals↗

[Protection of interleukin-1 receptor antagonist on epileptiform discharges induced by magnesium-free treatment in developing rat cortical neurons].

OBJECTIVE: To study the protection of IL-1ra in cultured developing neuron injury following Mg(2+)-free-induced epileptiform discharges. METHODS: Rat embryo cortical neurons cultured for 6 d and 17 d were directly exposed to Mg(2+)-free media, or pretreated with IL-1 receptor antagonist or NMDA receptor antagonists before being exposed to Mg(2+)-free media, and then returned to regular media.MTT assay was used to study mitochondrial function injury, laser-scanning confocal microscope to measure [Ca(2+)]i, and real-time RT-PCR to detect gene mRNA expression. RESULTS: (1) MTT conversion rates were higher in neurons pre and co treated with 10 mg/L IL-1ra than those of neurons with only Mg(2+)-free treatment in neurons cultured for 17 d, but not in neurons cultured for 6 d.(2) [Ca(2+)]i was lower in neurons pre and co-treated with 10 mg/L IL-1ra than those of neurons with only Mg(2+)-free treatment, either in neurons cultured for 6 d or in neurons cultured for 17 d, and the effects of IL-1ra on [Ca(2+)]i change were different between neurons cultured for 6 d and neurons cultured for 17 d.(3) Pre and co-treated with 10 mg/L IL-1ra NR1 mRNA expression increase induced by Mg(2+)-free treatment was decreased, either in neurons cultured for 6 d or neurons cultured for 17 d, and this effect showed no difference between neurons cultured for 6 d and 17 d; Pre and co-treated with 10 mg/L IL-1ra NR2A mRNA expression increase induced by Mg(2+)-free treatment in neurons cultured for 17 d was decreased, and NR2A mRNA expression showed no difference between IL-1ra group and age-matched control group, but have no effect on neurons cultured for 6 d; Pre and co-treated with 10 mg/L IL-1ra have NR2B mRNA expression increase induced by Mg(2+)-free treatment was not affected, either in neurons cultured for 6 d or neurons cultured for 17 d. CONCLUSION: Neuroprotection of IL-1Ra in seizure-induced injury is age-dependent. The mech-anism of the neuroprotection of IL-1Ra includes down-regulation of [Ca(2+)]i and others.

Animals↗