Antimicrobial activity of a bovine myeloid antimicrobial peptide (BMAP‐28) against methicillin‐susceptible and methicillin‐resistant Staphylococcus aureus

A bovine myeloid antimicrobial peptide (BMAP‐28) is a member of the cathelicidin family which is included in the innate immune system of mammals. Recently, there have been many studies about antimicrobial peptides. This study aims to clarify whether BMAP‐28 has bactericidal activity against methicillin‐resistant Staphylococcus aureus (MRSA) and compares its activity against methicillin‐susceptible S. aureus (MSSA) and MRSA. We found that the peptide was effective in killing MRSA (minimal inhibitory concentration (MIC) range; 5–20 µg/mL). It was also revealed that MSSA (MIC range; 1.25–20 µg/mL) had two levels of susceptibility to BMAP‐28. We also examined the effect of BMAP‐28 on bacterial shape to visually show its activity. After exposure to the peptide, both MSSA and MRSA cells showed the morphological changes on their surfaces. Our results indicate that BMAP‐28 is a promising candidate for medicine against drug‐resistant bacteria.     

Insulin-like Growth Factor 1 mRNA Expression in the Uterus of Streptozotocin-treated Diabetic Mice

Reproductive functions decline with the onset of diabetes in female mice. Diabetic mice have smaller uteri with an underdeveloped endometrium, suggesting diminished estrogen-induced growth. We aimed to clarify the changes in the estrous cycle and in insulin-like growth factor 1 (IGF1) expression in the uteri of streptozotocin (STZ)-treated diabetic mice, because IGF1 is one of the main growth factors involved in estrogen-induced uterine growth. ICR female mice were intraperitoneally administered STZ (10 mg/100 g BW), and blood glucose levels were determined. Mice with blood glucose levels > 200 mg/dl were classified as diabetic mice. The onset of diabetes was associated with acyclic estrous cycles. Diabetes was also induced with STZ in ovariectomized mice. Uterine Igf1 mRNA levels were reduced in ovariectomized STZ-treated diabetic mice. Estrogen is known to stimulate Igf1 mRNA expression in the uterus, but estrogen action was abolished in the uteri of STZ-treated diabetic mice. mRNA expressions of estrogen receptor α (ERα) and steroid hormone receptor coactivators (SRC-1/Ncoa1, SRC-2/Ncoa2, SRC-3/Ncoa3 and CBP/p300/Crebbp) were reduced in the uteri of ovariectomized STZ-treated diabetic mice. The present study demonstrates that diabetes induces a decline in female reproductive functions in mice. Igf1 expression in ovariectomized diabetic female mice was decreased, and decreased responsiveness to estrogen in the uteri of diabetic mice is probably associated with a reduction in ERα and steroid receptor coactivator mRNA expression.     

Deficits of learning and memory in Hemojuvelin knockout mice

Iron is involved in various physiological processes of the human body to maintain normal functions. Abnormal iron accumulation in brain has been reported as a pathogenesis of several neurodegenerative disorders and cognitive impairments. Hemojuvelin (HVJ) is a membrane-bound and soluble protein in mammals that is responsible for the iron overload condition known as juvenile hemochromatosis. Although iron accumulation in brain has been related to neurodegenerative diseases, it remains unknown the effect of mutation of HVJ gene on cognitive performance. In our studies, HJV(−/−) mice showed deficits in novel object recognition and Morris water maze tests. Furthermore, the expression ration of apoptotic marker Bax and anti-apoptotic marker Bcl-2 in the hippocampus and prefrontal cortex showed higher levels in HJV(−/−) mice. Our results suggested that deletion of HJV gene could increase apoptosis in brain which might contribute to learning and memory deficits in mutant mice. These results indicated that HJV(−/−) mice would be a useful model to study cognitive impairment induced by iron overload in brain.     

Somatic cell and innate immune responses in mammary glands of lactating cows to intramammary infusion of Bifidobacterium breve at pre-drying off period

Intramammary infusion of Bifidobacterium breve (B. breve)-induced somatic cell (SC) counts, chemiluminescent response (CL), lactoferrin (LF) concentrations and mastitis-causing pathogens from quarters with subclinical mastitis were measured to evaluate innate immune response of mammary glands in dairy cows at 3 to 4 weeks before drying off. SC counts in 7 quarters of 7 control cows and 5 quarters of 6 cows with mastitis increased markedly on day 1 and SC values in control cows were significantly (P<0.05) increased and returned to pre-infusion levels on day 5 after B. breve-infusion. CL values in both groups increased markedly on day 1 and then decreased after B. breve-infusion; however, CL values in cows with mastitis did not return to normal levels on day 5 and at postpartum. The CL values were highly correlated with their SC counts in milk from both groups. LF concentrations increased toward day 3 after B. breve-infusion and were higher in cows with mastitis. B. breve-infusion eliminated 16.6% (1/6) of pathogens from 6 quarters with chronic subclinical mastitis. B. breve-induced SC responses in quarters from 3 cows with mastitis showed characteristic patterns of recovery, persistent and new infections. B. breve-induced SC counts in quarters from the cows in the pre-drying off were lower (25.7–70.6%) than those of the cows in mid-lactation. The intrinsic innate immune response in cows on pre-drying off may be decreased and appears to be insufficient to eliminate pathogens from mammary gland in the pre-drying off.     

Expression dynamics of bovine MX genes in the endometrium and placenta during early to mid pregnancy

MX belongs to a family of type I interferon (IFN)-stimulated genes, and the MX protein has antiviral activity. MX has at least two isoforms, known as MX1 and MX2, in mammals. Moreover, bovine MX1 has been found to have alternative splice variants—namely, MX1-a and MX1B. In ruminants, IFN-τ—a type I IFN—is temporarily produced from the conceptus before implantation and induces MX expression in the endometrium. However, the expression dynamics of MX after implantation are not clear. In the present study, we investigated the expression of MX1-a, MX1B and MX2 in the endometrium and placenta before and after implantation along with the expression of IFN-α, type I receptors (IFNAR1 and IFNAR2) and interferon regulatory factors (IRF3 and IRF9). Pregnant uterine samples were divided into five groups according to pregnancy days 14–18, 25–40, 50–70, 80–100, and 130–150. Tissue samples were collected from the intercaruncular endometrium (IC), caruncular endometrium (C) and fetal placenta (P). Although all the MX expressions were significantly higher in the IC and C at days 14–18, presumably caused by embryo-secreted IFN-τ stimulation, their expressions were also detectable in the IC, C and P after implantation. Furthermore, IFN-α expression was significantly higher in the IC. RT-PCR indicated IFNAR1, IFNAR2, IRF3 and IRF9 mRNA in all the tissues during pregnancy. These results suggest that all the MX genes are affected by the type I IFN pathway during pregnancy and are involved in an immune response to protect the mother and fetus.     

Effect of ruminal dosing of mechanical stimulating brush on rumination time, ruminal passage rate and rumen fermentation status in Holstein steers fed a concentrate diet

This experiment was conducted to determine the effect of ruminal dosing of a mechanical stimulating brush on rumination time, ruminal passage rate and rumen fermentation status in steers fed a concentrate diet at maintenance level. Animals were dosed three Rumen Faibu (RF) per head through the rumen fistulae (RF treatment) and not dosed (control) in a change‐over design. The organic cell wall content of the concentrate diet was 12.7% of dry matter. Daily time spent on rumination was very short in both treatments with 24 min in RF treatment and 15 min in control. The turnover rate of ruminal fluid in RF treatment was higher than that in control. There were no differences in ruminal pH and total volatile fatty acid concentration between RF treatment and control. Acetic and butyric acid concentrations were not different between the treatments. Propionic acid concentration tended to be higher in the animals on RF treatment than in control animals. The RF dosing in Holstein steers fed a low fiber diet did not affect the rumination time, but increased rumen digesta passage rate and ruminal propionic acid production.     

The Effects of Frequent Electroejaculation on the Semen Characteristics of a Captive Siberian Tiger (Panthera tigris altaica)

Artificial insemination (AI) can help to avoid inbreeding and genetic degeneration for sustaining genetically healthy populations of endangered species in captivity. Collection of a sufficient quantity of viable sperm is an essential first step in the AI process. In the present study, we examined the effects of frequent electroejaculation on semen characteristics in a Siberian tiger. We collected semen in all 17 trials during 6 breeding seasons (6 years). The mean number of sperm and the percentage of motile sperm were 294.3 ± 250.2×10⁶/ejaculate and 82.4 ± 11.4%, respectively. The number of motile sperm tended to increase during frequent electroejaculation in the same breeding season. Semen collection by electroejaculation can be performed effectively up to the fourth sequential ejaculate, which contained the most sperm in the study. In conclusion, frequent collection of sperm by electroejaculation from tigers may be effective for collection of a large number of motile sperm.     

Comparison of cholesterol levels among lipoprotein fractions separated by anion-exchange high-performance liquid chromatography in periparturient Holstein–Friesian dairy cows

Changes in lipoprotein profiles occur in dairy cows during the periparturient period and in cows with transition cow disease. Here, the lipoprotein profiles of Holstein–Friesian dairy cows during the periparturient period were obtained by anion-exchange, high-performance liquid chromatography to evaluate the usefulness of lipoprotein profile evaluation during the periparturient period and in cows with fatty liver and milk fever. Lipoprotein levels (including total and high- (HDL-C) and low-density lipoprotein (LDL-C) cholesterol) in 10 healthy cows were low 4 weeks prepartum, with the lowest values at calving or within 1 week of calving; the values increased at 8 weeks postpartum. The lipoprotein levels were measured in 16 cows diagnosed with fatty liver (n=10) or milk fever (n=6) and compared to 10 healthy dairy cows. A significant difference was observed in HDL-C between healthy cows (at calving and 1 week postpartum), and the fatty liver and milk fever cows. Cows with fatty liver and milk fever had a lower mean HDL-C than the 10 healthy dairy cows at calving and 1 week postpartum. HDL-C might be a good indicator of energy balance for differentiating healthy cows from those with transition cow disease.     

Potential of near infrared spectroscopy to determine the lipid content of untreated garbage compost

The purpose of the present study was to evaluate the capability of near infrared spectroscopy (NIRS) as a simple method to monitor the lipid content of garbage compost, which is a potential inhibitor of plant growth. We conducted a cultivation experiment with vegetable mock pak choy ( Brassica rapa L. Parachinensis Group) using two application rates of four garbage composts that differed in lipid content. The input of lipid from the compost to the field showed a significant negative correlation with germination rate and plant height in the initial growth stage. Reflectance spectra of untreated and freeze-dried and milled compost samples were taken using a scanning monochromator. Second-derivative spectra and multiple regression analysis were used to develop calibration equations for lipid and moisture contents. The calibration was carried out with the short wavelength region ([SWR] 800–1100 nm) and the long wavelength region ([LWR] 1100–2500 nm) separately. The calibration equations with the LWR were more accurate than those with the SWR for lipid and moisture determinations. The accuracies of the calibration equations for untreated samples were comparable to those for freeze-dried and milled samples. In conclusion, we suggest that the application rate of garbage compost can be determined by measuring the lipid content of untreated samples by NIRS.     

CHARACTERIZATION OF CANINE FOCAL LIVER LESIONS WITH CONTRAST-ENHANCED ULTRASOUND USING A NOVEL CONTRAST AGENT—SONAZOID

Contrast-enhanced ultrasound using Sonazoid, a novel contrast medium with a liver-specific Kupffer phase, was evaluated in canine focal liver lesions Twenty-five dogs with a liver mass were given intravenous Sonazoid, and the enhancement pattern in the arterial, portal, and parenchymal phase was characterized. An enhancement defect in the lesion in the parenchymal phase was observed in all malignant lesions, whereas only one of nine benign lesions had a filling defect. The diagnostic value of the presence of a filling defect for malignancy was statistically significant (100% sensitivity, 88.9% specificity, 94.1% positive predictive value, 100% negative predictive value), and was equal to that of hypoenhancement in the portal or delayed phase. The defect pattern (clear or irregular defect) was dependent ( P <0.05) on the types of malignancy (i.e., hepatocellular carcinoma and other types of malignancies). In the arterial phase, five of the six hepatocellular carcinomas had hypervascularity, whereas no other lesion was characterized by hypervascularity. In some dogs, additional lesions that could not be observed with conventional B-mode ultrasonography were detected in the parenchymal phase. The enhancement pattern of Sonazoid, especially in the parenchymal phase, has potential as a diagnostic tool for canine focal liver lesions.