Spermatozoa from the maned wolf (Chrysocyon brachyurus) display typical canid hyper-sensitivity to osmotic and freezing-induced injury,but respond favorably to dimethyl sulfoxide

We assessed the influences of medium osmolality, cryoprotectant and cooling and warming rate on maned wolf (Chrysocyon brachyurus) spermatozoa. Ejaculates were exposed to Ham’s F10 medium (isotonic control) or to this medium plus NaCl (350–1000 mOsm), sucrose (369 and 479 mOsm), 1 M glycerol (1086 mOsm) or dimethyl sulfoxide (Me₂SO, 1151 mOsm) for 10 min. Each sample then was diluted back into Ham’s medium and assessed for sperm motility and plasma membrane integrity. Although glycerol and Me₂SO had no influence (P > 0.05), NaCl and sucrose solutions affected sperm motility (P < 0.05), but not membrane integrity. Motility of sperm exposed to <600 mOsm NaCl or sucrose was less (P < 0.05) than fresh ejaculate, but comparable (P > 0.05) to the control. As osmolality of the NaCl solution increased, motility decreased to <5%. In a separate study, ejaculates were diluted in Test Yolk Buffer containing 1 M glycerol or Me₂SO and cooled from 5 °C to −120 °C at −57.8 °C, −124.2 °C or −67.0 °C/min, frozen in LN₂, thawed in a water bath for 30 s at 37 °C or 10 s at 50 °C, and then assessed for motility, plasma- and acrosomal membrane integrity. Cryopreservation markedly (P < 0.05) reduced sperm motility by 70% compared to fresh samples. Higher (P < 0.05) post-thaw motility (20.0 ± 1.9% versus 13.5 ± 2.1%) and membrane integrity (51.2 ± 1.7% versus 41.5 ± 2.2%) were observed in samples cryopreserved in Me₂SO than in glycerol. Cooling rates influenced survival of sperm cryopreserved in glycerol with −57.8 °C/min being advantageous (P < 0.05). The findings demonstrate that although maned wolf spermatozoa are similar to domestic dog sperm in their sensitivity to osmotic-induced motility damage, the plasma membranes tolerate dehydration, and the cells respond favorably to Me₂SO as a cryoprotectant.     

Plasma ADMA concentrations associate with aerobic fitness in postmenopausal women

Aims

Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of nitric oxide (NO) synthase, an enzyme responsible for the generation of NO. Plasma concentrations of ADMA increase in the elderly and in postmenopausal women. In fact, an elevated ADMA level is a risk factor of cardiovascular disease. Aerobic exercise has a beneficial effect on cardiovascular disease. However, the relationship between ADMA and aerobic fitness is unknown. The aim of this study was to determine whether plasma ADMA concentrations correlate with aerobic fitness levels in postmenopausal women.

Main methods

Thirty healthy postmenopausal women aged 50–76 years participated in this study. We measured plasma concentrations of ADMA and oxygen consumption at the ventilatory threshold (VO_2VT) as an index of aerobic fitness. Subjects were divided into the low aerobic fitness (Low fitness) and high aerobic fitness (High fitness) groups, and the dividing line was set at the median VO_2VT value.

Key findings

VO_2VT was significantly higher in the High fitness group than in the Low fitness group (P < 0.01). The plasma ADMA concentrations in the High fitness group were significantly lower than those in the Low fitness group (P < 0.05). There was a negative correlation between plasma ADMA concentrations and VO_2VT (r = − 0.532, P < 0.01).

Significance

We found that plasma ADMA concentrations were associated with aerobic fitness in postmenopausal women. The results of this study suggest that habitual aerobic exercise may decrease plasma ADMA concentrations.     

Rosiglitazone transiently disturbs calcium homeostasis in monocytic cells

The PPARγ agonist Rosiglitazone exerts anti-hyperglycaemic effects by regulating the long-term expression of genes involved in metabolism, differentiation and inflammation. In the present study, Rosiglitazone treatment rapidly inhibited (5-30 min) the ER Ca²⁺ ATPase SERCA2b in monocytic cells (IC₅₀ = 1.88 μM; p < 0.05), thereby disrupting short-term Ca²⁺ homeostasis (resting [Ca²⁺]_cyto = 121.2 ± 2.9% basal within 1 h; p < 0.05). However, extended Rosiglitazone treatment (72 h) induced dose-dependent SERCA2b up-regulation, and restored calcium homeostasis, in monocytic cells (SERCA2b mRNA: 138.7 ± 5.7% basal (1 μM)/215.0 ± 30.9% basal (10 μM); resting [Ca²⁺]_cyto = 97.3 ± 8.3% basal (10 μM)). As unfavourable cardiovascular outcomes, possibly related to disrupted cellular Ca²⁺ homeostasis, have been linked to Rosiglitazone, this effect may be of clinical interest. In contrast, in PPRE-luciferase reporter-gene assays, Rosiglitazone induced non-dose-dependent PPARγ-dependent effects (1 μM: 152.5 ± 4.9% basal; 10 μM: 136.1 ± 5.1% basal (p < 0.05 for 1 μM vs. 10 μM)). Thus, we conclude that Rosiglitazone can exert PPARγ-independent non-genomic effects, such as the SERCA2b inhibition seen here, but that long-term Rosiglitazone treatment did not perturb resting [Ca]_cyto in this study.     

15-Ketodihydro-PGF2α and cortisol plasma concentrations in newborn foals after spontaneous or oxytocin-induced parturition

Hormonal changes during early neonatal life play a major role in the physiological processes underlying the maturation of several organs. Since prostaglandins and cortisol are associated with fetal organ system maturation, the aim of this study was to evaluate 15-ketodihydro-PGF_2α (PGM) and cortisol plasma concentrations during the first 21 days after birth in foals born by either spontaneous (24 foals) or low-dose oxytocin (OT)-induced parturition performed after at least 320 gestational days (25 foals) since induction is often considered to be a cause of prematurity. After spontaneous birth, the PGM concentration was significantly (P < 0.05) higher at 20 and 30 min compared to samples taken several hours or days later, while induced foals showed significantly (P < 0.05) higher concentrations at 10, 20, and 30 min. Regarding differences between the two groups, the plasma concentration of PGM was significantly higher 10 (P < 0.01), 20 (P < 0.05), and 30 (P < 0.05) min and 3 h (P < 0.05) after birth in induced foals compared to foals born by spontaneous parturition. It is difficult to determine whether the higher initial PGM concentrations in induced foals is related to higher uterine or fetal PGM release induced by exogenous OT stimulation. Cortisol plasma levels in both groups were higher at birth (P < 0.05) compared to the later sampling times. No differences were observed between the two groups indicating that the induction protocol used does not seem to result in premature foals.     

Effects of progesterone presynchronization and eCG on pregnancy rates to GnRH-based, timed-AI in beef cattle

Three experiments were conducted to determine the effects of low-dose progesterone presynchronization and eCG on pregnancy rates to GnRH-based, timed-AI (TAI) in beef cattle (GnRH on Day 0, PGF_2α on Day 7, with GnRH and TAI on Day 9, 54-56 h after PGF_2α). Experiments 1 and 2 were 2 × 2 factorials with presynchronization (with or without a once-used CIDR; Days −15 to 0 in Experiment 1 and Days −7 to 0, with PGF_2α at insertion, in Experiment 2), and with or without 400 IU eCG on Day 7 in suckled cows. In Experiment 3, suckled cows and nulliparous heifers were either presynchronized with a twice-used CIDR (Days −5 to 0) and PGF_2α at insertion, or no treatment prior to insertion of a new CIDR (Days 0-7). Presynchronization increased (P < 0.05) ovulation rate to GnRH on Day 0 (75.0% vs 48.7%, 76.7% vs 55.0%, and 60.0% vs 36.1% for Experiments 1, 2, and 3, respectively), increased the diameter of the preovulatory follicle in Experiments 1 and 2, and increased the response to PGF_2α (regardless of parity) in Experiment 1 (P < 0.01), and in primiparous cows in Experiment 2 (P < 0.01). Effects of presynchronization on pregnancy rates (53.4% vs 54.1%, 57.7% vs 45.3%, and 54.3% vs 44.4% for Experiments 1, 2, and 3, respectively) were influenced by parity and eCG (P < 0.05). Treatment with eCG had no effect (P > 0.05) on the diameter of the preovulatory follicle (Experiment 1), or the response to PGF_2α (Experiments 1 and 2), but tended (P = 0.08) to improve pregnancy rates, especially in primiparous cows that were not presynchronized (P < 0.01). However, the effects of eCG and presynchronization were not additive.     

Vanadium and 1, 25 (OH)2 vitamin D3 combination in inhibitions of 1,2, dimethylhydrazine-induced rat colon carcinogenesis

The current investigation demonstrates the antitumor effects of combined supplementations of vanadium (V) (4.27 µmol/L drinking water ad libitum) and1α, 25-dihydroxy vitamin D₃ (Vitamin D₃) (0.3 μg/100 μL propylene glycol per os twice a week) on 1, 2 dimethylhydrazine (DMH) (20 mg/kg body weight) induced rat colon carcinogenesis. There was a significant reduction in incidence (70%), multiplicity (P < 0.0001) and volume (P < 0.01) of colon tumors. HPLC-fluorescence assay detected the combinatorial actions of V and Vitamin D₃ against DMH-induced colonic O⁶-methylguanine DNA adducts formation (at four sequential time points; ANOVA, F = 13.56, P < 0.01). Simultaneous inhibition of DNA single strand breaks (P < 0.001) indicates the potency of the combination regimen in limiting the initiation event of colon carcinogenesis. Immunohistochemical analysis revealed that the effect of V and vitamin D₃ occurred through suppression of cell proliferation (BrdU-LI: P < 0.001) along with an induction of apoptosis (TUNEL-LI: P < 0.01). The immunoexpression of tumor suppressor p53 and downregulation of antiapoptotic protein BCl-2 in subsequent immunofluorescence assay further provide strong evidence for the combinatorial inhibitory actions of vanadium and vitamin D₃ against DMH-induced rat colon carcinogenesis.     

Protective effect of piperine on electrophysiology abnormalities of left atrial myocytes induced by hydrogen peroxide in rabbits

Aims

Piperine had protective effects on oxidative stress damage of ventricular myocytes by hydrogen peroxide (H₂O₂). In this study we aimed to explore the protective effect of piperine on abnormalities of the cardiac action potential (AP) and several ion currents induced by hydrogen peroxide (H₂O₂) in single rabbit left atrial myocyte.

Main methods

Conventional microelectrodes were used to record action potential duration (APD), resting membrane potential (RMP) and some ion currents (I_Ca,L,I_to,I_K1 and I_kur,ect.), before and after H₂O₂ administration with or without piperine.

Key findings

The piperine (7 μmol/L) had no significant effect on APD, I_Ca,L,I_to,I_K1 and I_kur and their channel dynamics. In the presence of 50 μmol/L H₂O₂, APD₅₀ and APD₉₀ shortened (P < 0.01), amplitude of RMP decreased (P < 0.05), the peak of I_Ca,L reduced significantly (P < 0.05). Piperine (7 μmol/L) significantly alleviated the inhibiting effect of H₂O₂ on APD and I_Ca,L (P < 0.01) and protected the changes of I_Ca,L dynamics induced by H₂O₂. The peak current of I_to was reduced significantly (P < 0.05); Piperine (7 μmol/L) significantly alleviated the inhibiting effect of H₂O₂ on I_to (P < 0.01). In addition, piperine protected the changes of I_to dynamics induced by H₂O_2. The peak current of I_K1 and I_KUr was significantly reduced (P < 0.05); Piperine (7 μmol/L) alleviated the inhibiting effect of H₂O₂ on I_K1 and I_KUr significantly (P < 0.01). In addition, piperine protected the changes of I_KUr dynamics induced by H₂O₂.

Significance

These results suggest that piperine effectively protects atrial myocytes from oxidative stress injury in atrial electrophysiology.     

In vivo response of melatonin,gonadal activity and biochemical changes during CYP19 inhibited sex reversal in common carp Cyprinus carpio (L)

CYP19 aromatase is the key enzyme in vertebrate steroidogenesis, catalyzing the conversion of C19 androgens to 17β-estradiol (E₂). The objective of the present study was to assess the effect of the CYP19 inhibitors (AIs) fadrozole and anastrozole on gonadal development and sex differentiation in Cyprinus carpio and investigate the possible involvement of in vivo melatonin (MLT) production during sex differentiation. The CYP19 activity in 30 day-post fertilized (30 dpf) fingerlings was inhibited by treating with fadrozole and anastrozole in doses of 100 mg/kg and 200 mg/kg of feed. Gonado-somatic-index (GSI) of fish decreased (P < 0.005) and the changes in GSI was dose dependent. Serum testosterone (T) concentration increased (P < 0.001) after AI treatments and was negatively correlated with serum E₂ concentration which decreased (P < 0.005). Morning serum MLT concentration decreased during the period of inhibited CYP19 activity with a positive correlation with E₂ concentration. Sex-ratio in anastrazole (200 mg/kg) treated fish were 98.1% males while with fadrozole treatment at the same dose resulted in a 97.1% masculinization. Histological examination of fadrozole-treated fish gonads resulted in detection of atretic follicles and intensified spermiation. The protein and lipid production was depressed in AIs-treated fish. The results suggested that fadrozole and anastrozole both effectively inhibited oogenesis and ovarian development in C. carpio accelerating testicular formation. There was a physiological correlation between CYP19 activity, E₂ and MLT synthesis during gonadal development and sex differentiation.     

Plant growth, community structure, and nutrient removal in monoculture and mixed constructed wetlands

The aim of this study was to compare the growth, community structure, and nutrient removal rates between monoculture and mixed wetlands, based on the hypothesis that it depends on the plant species used in the wetlands as to whether monoculture or mixed wetland is superior in plant growth and nutrient removal. Pilot-scale monoculture and mixed constructed wetlands were studied over 4 years. The monoculture wetland had a community height similar to the mixed wetland during the early years but a significantly lower height than the mixed wetland (P < 0.05) during the last year. The mixed wetland also displayed a higher plant density than the monoculture wetland (P < 0.05). The leaf area index in the monoculture wetland was significantly higher in the first year (P < 0.05) and significantly lower in the later years (P < 0.05) than that in the mixed wetland. The monoculture wetland had a similar vertical distribution of below-ground biomass over 4 years, while the mixed wetland showed a significant change in vertical distribution of below-ground biomass in the last 2 years. The monoculture wetland had a larger (P < 0.05) above-ground biomass and a similar leaf biomass in the first year, and a smaller above-ground biomass (P < 0.05) and a smaller leaf biomass (P < 0.05) than the mixed wetland during the latter 2 years. The amount of standing dead mass was smaller in the mixed wetland than in the monoculture wetland (P < 0.05). The mixed wetland exhibited a significantly lower NH₄-N removal rate in the first year (P < 0.05), and significantly higher NH₄-N removal rate in the last year, when compared to the monoculture wetland (P < 0.05). The study indicated that species competition and stubble growth resulted in significant differences between monoculture and mixed constructed wetlands in plant growth, community structure, and nutrient removal rates.     

Protective effects of veskamide, enferamide, becatamide, and oretamide on H2O2-induced apoptosis of PC-12 cells

Veskamide, enferamide, becatamide, and oretamide are phenolic amides whose analogues are found in plants. In this study, the four amides were prepared by chemical synthesis and their protective effects on H₂O₂-induced apoptosis in PC-12 cells were investigated. The syntheses were relatively simple and the yields were more than 43%. Using NMR spectroscopic methods, the chemical structures of veskamide, enferamide, becatamide, and oretamide were confirmed. The decreasing order of the protective effects on H₂O₂-induced apoptosis was becatamide > enferamide ≥ oretamide > veskamide. In fact, becatamide suppressed H₂O₂-induced mitochondrial membrane depolarization in a dose-dependent manner. At the concentration of 10 μM, becatamide maintained mitochondrial membrane depolarization at 16% compared to 51% in H₂O₂-treated PC-12 cells (P < 0.05). Also, at the same concentration, becatamide inhibited H₂O₂-induced caspase-9 activation and caspase-independent chromatin condensation by 68% (P < 0.05) and 73% (P < 0.05), respectively. This is the first report about the chemical synthesis of becatamide and its potential biological activity to inhibit H₂O₂-induced apoptosis of PC-12 cells via protecting mitochondrial membrane integrity, thereby suppressing caspase-9 activation and chromatin condensation.     

Rapid down-regulation of mitochondrial fat metabolism in human muscle after training cessation is dissociated from changes in insulin sensitivity

The association between impairment in mitochondrial muscle fat oxidative capacity (OX_FA) and occurrence of insulin resistance was examined in 14 healthy trained men (age, 24 ± 4 yr) submitted to 4 weeks of training cessation. Training stop induced a significant decrease in mRNA levels of proteins involved in muscle fat metabolism, particularly PPARα (−58%, P < 0.01) and PGC-1α (−30%, P < 0.05), a 21% reduction in OX_FA (P < 0.01), and reduced fat oxidation during moderately intense exercise (P < 0.05). In contrast, there was no significant alteration in insulin sensitivity. In conclusion, decline in OX_FA is a rapid metabolic event following training cessation. It is involved in the regulation of whole body fat balance but not in the deterioration of insulin sensitivity.     

Population genetic differentiation of Schisandra chinensis and Schisandra sphenanthera as revealed by ISSR analysis

Schisandra chinensis (Turcz.) Baill. and Schisandra sphenanthera Rehd. et Wils. are well-known Chinese medicinal plants. The population genetic variation of the two species was studied using inter simple sequence repeat (ISSR) molecular markers. High levels of genetic diversity are revealed in both S. chinensis (P = 88.36%, h = 0.2894, I = 0.4396) and S. sphenanthera (P = 84.09%, H = 0.2782, I = 0.4280). However, the population genetic differentiation is significantly different between the two species. The S. sphenanthera harbors as high as 27% of the genetic variation among populations but 73% within populations, whereas in S. chinensis 17% of the genetic variation occurs among populations and 83% within populations. Both significant (P < 0.05) heterozygosity excess and shifted mode of allele frequency distribution are detected in four out of six populations of S. chinensis and one out of five populations of S. sphenanthera, suggesting the occurrence of recent population bottlenecks in the two species. The different patterns of genetic variation in S. chinensis and S. sphenanthera are discussed in relation to their differences in pollination mechanism, geographic distribution and historical events, and the level of gene flow and genetic drift.     

Anti-diabetic effects of sodium 4-amino-2,6-dipicolinatodioxovanadium(V) dihydrate in streptozotocin-induced diabetic rats

The evaluation of the anti-diabetic effects of an organic vanadium(V) complex in streptozotocin (STZ)-induced diabetic rats was investigated. The STZ-induced diabetic rats were orally administrated with sodium 4-amino-2,6-dipicolinatodioxovanadium(V) dihydrate (V5dipic-NH₂), a vanadium(V) coordination compound. The compound was administered through drinking water at a concentration of 0.1 mg/mL for 20 days, and then the concentration was increased to 0.3 mg/mL for the following 20 days. At the end of the experiment, V5dipic-NH₂ statistically significantly reduced the levels of blood glucose (P < 0.01), serum total cholesterol (P < 0.01), triglycerides (P < 0.01) and the activities of serum aspartate amino transferase (P < 0.05) and alkaline phosphatase (P < 0.01) compared to untreated diabetic animals. After treatment with 0.3 mg/mL V5dipic-NH₂, the oral glucose tolerance was improved in diabetic animals (P < 0.01). In addition, the daily intake of elemental vanadium was markedly decreased in V5dipic-NH₂-treated diabetic rats compared to vanadyl sulfate (VOSO₄)-treated diabetic rats, which suggested that the anti-diabetic activity of the element vanadium was elevated after being modified with an organic ligand. These results suggested that V5dipic-NH₂, as an organic vanadium compound, is more effective than inorganic vanadium salt at alleviating the symptoms of diabetes.     

Laboratory experiments on the effects of variable suspended sediment concentrations on the ecophysiology of the porcelain crab Petrolisthes elongatus (Milne Edwards, 1837)

The porcelain crab Petrolisthes elongatus is a particulate suspension feeding species common to coastal areas of New Zealand (NZ). Consistent with the responses of other suspension feeding species, it is likely to be negatively influenced by elevated suspended sediment concentrations. Laboratory experiments were conducted to quantify the effect of temperature (12 °C, 15 °C and 18 °C) and suspended sediment concentration (total particulate matter (TPM): low < 100 mg L^− 1; medium 100-1000 mg L^− 1; high > 1000 mg L^− 1) on the clearance rate (CR in L h^− 1), oxygen uptake rate (VO₂ in mL h⁻¹), net absorption efficiency (AE), and net energy budget (NEB in J h^− 1) of P. elongatus across a range of sizes. Variation in CR and AE was independent of temperature and of body size, but were significantly different (P < 0.05) at low and medium suspended sediment concentrations compared with high suspended sediment concentrations. CR responded in a non-linear manner to changes in TPM, increasing with TPM up to a maximum value at medium-low concentrations (approximately 250 mg L^− 1) and then decreasing thereafter. CR had almost completely shut down at TPM concentrations of > 1000 mg L^− 1 and at particulate organic matter (POM) concentrations of > 250 mg L^− 1. AE was zero at approximate TPM and POM values of 1200 mg L^− 1 and 300 mg L^− 1, respectively. VO₂ was positively correlated with body size and with temperature, but was independent of TPM. NEB values for P. elongatus were low (approx 110 J g^− 1 h^− 1) at low sediment concentrations, were high (approx 320 J g^− 1 h^− 1) at medium sediment concentrations, and were negative (approx − 114 J g^− 1 h^− 1) at high sediment concentrations. These findings indicate that P. elongatus is likely to be food-limited at sediment concentrations of < 100 mg L^− 1, and severely negatively affected at sediment concentrations of > 1000 mg L^− 1, at least for the duration of such events which may persist for 2-3 days in coastal environments where this crab occurs.     

Impact of buserelin acetate or hCG administration on day 12 post-ovulation on subsequent luteal profile and conception rate in buffalo (Bubalus bubalis)

The present study investigated the impact of gonadotropic hormone administration on day 12 post-ovulation on subsequent luteal profile and conception rate in buffaloes. All the buffaloes (n = 48) were estrus synchronized by a synthetic analogue of prostaglandin F_2α (PGF_2α), administered 11 days apart, followed by insemination during mid to late estrus. To examine the effect of mid-luteal phase hormonal treatment, buffaloes were randomly divided into control (normal saline, n = 14), d12-BA (buserelin acetate, 20 μg, n = 17) and d12-hCG (hCG, 3000 IU, n = 17) groups. Ovaries were scanned on the day of induced estrus to measure the preovulatory follicle (POF) diameter and on days 5, 12, 16 and 21 post-ovulation to examine the alterations in corpus luteum (CL) diameter. On the day of each sonography, blood samples were collected for the estimation of plasma progesterone. In treatment groups, luteal profile (CL diameter and plasma progesterone) on day 16–21 post-ovulation was better (P < 0.05) as well as first service conception rate was higher (52.9% in each treatment group vs. 28.6%, P > 0.05) compared to controls. All the pregnant buffaloes exhibited higher (P < 0.05) plasma progesterone on various post-ovulation days than their respective non-pregnant counterparts. Treatment-induced accessory corpus luteum (ACL) formation was observed in 58.8 per cent and 70.6 per cent buffaloes of d12-BA and d12-hCG group, respectively, that also had higher (P < 0.05) plasma progesterone compared to controls. Compared to the spontaneous CL, the diameter of ACL was less (P < 0.05) in the treatment groups. In conclusion, buserelin acetate and hCG administration on day 12 post-ovulation leads to accessory CL formation, improves luteal profile and consequently increases conception rate in buffaloes.     

Spatial distribution of brood-bearing females of limnetic species of Cladocera

In this study, the spatial distribution of brood-bearing females of five species of limnetic cladocerans (Daphnia cucullata, D. longispina, Bosmina coregoni, B. longirostris, Diaphanosoma brachyurum) in the deep mesotrophic lake in relation to the predation pressure of planktivorous fish (roach Rutilus rutilus, perch Perca fluviatilis, catfish Ictalurus nebulosus, white fish Coregonus albula, bleak Alburnus alburnus), and planktonic invertebrates (cyclopoids Mesocyclops leuckartii, Thermocyclops oithonoides, T. crassus, and cladoceran Leptodora kindtii) as well as some environmental variables was estimated. Most cladocerans showed apparent differences in horizontal distribution (ANOVA F = 0.2–0.45, P < 0.05) in the littoral zone and lack of such differences in the pelagic zone (F = 0.07–0.13, P > 0.05). Vertical distribution of most species, in turn, showed a clear pattern in the pelagic zone (F = 0.31–0.39, P < 0.05) and less regularities in the littoral zone (F = 0.15–029, P > 0.05). The differences in spatial distribution of non-predated and predated species suggest that predation pressure, but not predatory type, was an important factor structuring their distribution. Other factors that affected their distribution were conductivity, dissolved oxygen, TOC and macrophyte biomass; however, most of those variables better explained the distribution of brood-bearing cladocerans in the vertical than horizontal aspect.     

N-acylhydrazone improves exercise intolerance in rats submitted to myocardial infarction by the recovery of calcium homeostasis in skeletal muscle

Aims

This work investigated the effects of 3,4-methylenedioxybenzoyl-2-thienylhydrazone (LASSBio-294) treatment on the contractile response of soleus (SOL) muscle from rats submitted to myocardial infarction (MI).

Main methods

Following coronary artery ligation, LASSBio-294 (2 mg/kg, i.p.) or vehicle was administrated once daily for 4 weeks.

Key findings

The run time to fatigue for sham rats was 17.9 ± 2.6 min, and it was reduced to 3.3 ± 0.8 min (P < 0.05) in MI rats. In MI rats treated with LASSBio-294, the time to fatigue was 15.1 ± 3.6 min. During the contractile test, SOL muscles from sham rats showed a response of 7.12 ± 0.54 N/cm² at 60 Hz, which was decreased to 5.45 ± 0.49 N/cm² (P < 0.05) in MI rats. The contractility of SOL muscles from the MI-LASSBio-294 group was increased to 9.01 ± 0.65 N/cm². At 16 mM caffeine, the contractility was reduced from 2.31 ± 0.33 to 1.60 ± 0.21 N/cm² (P < 0.05) in the MI group. In SOL muscles from MI-LASSBio-294 rats, the caffeine response was increased to 2.62 ± 0.33 N/cm². Moreover, SERCA2a expression in SOL muscles was decreased by 0.31-fold (31%) in the MI group compared to the Sham group (P < 0.05). In the MI-LASSBio-294 group, it was increased by 1.53-fold (153%) compared to the MI group (P < 0.05). Meanwhile, the nuclear density in SOL muscles was increased in the MI group compared to the Sham group. Treatment with LASSBio-294 prevented this enhancement of cellular infiltrate.

Significance

LASSBio-294 treatment prevented the development of muscular fatigue and improved exercise intolerance in rats submitted to MI.     

Identification of bovine NPC1 gene cSNPs and their effects on body size traits of Qinchuan cattle

NPC1 gene is an important gene closely related to the Niemann–Pick type C (NPC). Mutations in the NPC1 gene tend to cause Niemann–Pick type C, a lysosomal storage disorder. Previous studies have shown that NPC1 protein plays an important role in subcellular lipid transport, homeostasis, platelet function and formation, which are basic metabolic activities in the process of development. In this study, to explore the association between the NPC1 gene variation and body size traits in Qinchuan cattle, we detected four novel coding single nucleotide polymorphisms (cSNPs) in the bovine NPC1 gene, including one missense mutation (SNP1) and three synonymous mutations (SNP2, SNP3 and SNP4). Population genetic analyses of 518 individuals and association correlations between cSNPs and bovine body size traits were conducted in this research. A missense mutation at SNP1 locus was found to be significantly related to the heart girth, hip width and body weight (P < 0.01 or P < 0.05, 3.5-year-old). Two synonymous mutations at SNP2 and SNP3 loci also showed significant effects on hip width (P < 0.05, 3.5-year-old). One synonymous mutation at SNP4 locus showed significant effect on body weight (P < 0.05, 2.0-year-old). Combined haplotypes H₂H₆ and H₆H₆ showed significant effects on body size traits such as heart girth, hip width, and body weight (3.5-year-old, P < 0.01 or P < 0.05). This study provides evidence that the NPC1 gene might be involved in the regulation of bovine growth and body development, and may be considered as a candidate gene for marker assisted selection (MAS) in beef cattle breeding industry.     

Intra-cervical application of Misoprostol at estrus alters the content of cervical hyaluronan and the mRNA expression of follicle stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR) and cyclooxygenase-2 in the ewe

The complex anatomy the of ovine cervix limits the success of transcervical artificial insemination in sheep, but Misoprostol (a PGE₁ analogue) relaxes the cervix and facilitates transcervical artificial insemination. However, the mechanism by which Misoprostol causes cervical relaxation is not known. This study examined if intra-cervical Misoprostol altered the hyaluronan content and the mRNA expression of COX-2, LHR, or FSHR in the cervix of the estrus ewe. Estrus was synchronized in cyclic ewes with progestagen pessaries and 48 h after sponge removal ewes were treated intra-cervically with 0 (controls), 200, or 400 μg Misoprostol. Hyaluronan content was determined by ELISA and mRNA expression of LHR, FSHR, and COX-2 was analyzed by in situ hybridization using digoxigenin-11-uridine-5′-triphosphate labeled riboprobes. The hyaluronan content of the cervix was significantly higher in sheep that received 200 (P < 0.05) or 400 (P < 0.05) μg Misoprostol compared to controls. Moreover, it was significantly (P < 0.05) higher in the vaginal region compared to mid and uterine regions. Misoprostol increased (P < 0.05) the mRNA expression of LHR and COX-2 but not FSHR. The expression for all three genes was highest in the vaginal region and lowest in uterine region. The luminal epithelium and circular smooth muscle layers had higher (P < 0.05) expression for LHR, FSHR, and COX-2 mRNAs, and the sub-epithelial stroma had the lowest (P < 0.05). We propose that the intra-cervical application of Misoprostol induces the mRNA expression of LHR, FSHR, and COX-2 through a positive feedback loop. The data suggest that softening of the cervix by Misoprostol is caused by an increase in the hyaluronan content of the cervix.     

A novel hypothesis regarding the possible involvement of cytosolic phospholipase 2 in insulin-stimulated proliferation of vascular smooth muscle cells

Insulin (INS) via INS receptor acts as a mitogen in vascular smooth muscle cells (VSMCs) through stimulation of multiple signaling mechanisms, including p42/44 mitogen-activated protein kinase (ERK1/2) and phosphatidyl inositol-3 kinase (PI3K). In addition, cytosolic phospholipase 2 (cPLA₂) is linked to VSMCs proliferation. However, the upstream mechanisms responsible for activation of cPLA₂ are not well defined. Therefore, this investigation used primary cultured rat VSMCs to examine the role of PI3K and ERK1/2 in the INS-dependent phosphorylation of cPLA₂ and proliferation induced by INS. Exposure of VSMCs to INS (100 nM) for 10 min increased the phosphorylation of cPLA₂ by 1.5-fold (p < 0.01), which was blocked by the cPLA₂ inhibitor MAFP (10 μM; 15 min). Similarly, the PI3K inhibitor LY294002 (10 μM; 15 min) and ERK1/2 inhibitor PD98059 (20 μM; 15 min) abolished the INS-mediated increase in cPLA₂ phosphorylation by 59% (p < 0.001), and by 75% (p < 0.001), respectively. Further, inhibition of cPLA₂ with cPLA₂ inhibitor MAFP abolished the INS-stimulated ERK1/2 phosphorylation by 65% (p < 0.01). Incubation of rat VSMCs with INS resulted in an increase of VSMCs proliferation by 85% (p < 0.001). The effect of INS on VSMCs proliferation was significantly (p < 0.01) reduced by pretreatment with MAFP. Thus, we hypothesized that INS stimulates VSMCs proliferation via a mechanism involving the PI3K-dependent activation of cPLA₂ and release of arachidonic acid (AA), which activates ERK1/2 and further amplifies cPLA₂ activity.