Approach of allelopathy study with Arabidopsis thaliana (L.) Hevnh. and Neurospora crassa

Allelopathy in Arabidopsis seeds was investigated in the present study because there are few available reports of allelopathy studies regarding the early development stage of the plant life cycle, and because Arabidopsis is widely used as a model plant for molecular biology. When cockscomb ( Celosia cristata ) was incubated together with Arabidopsis seeds, the growth of cockscomb was promoted by Arabidopsis seeds. Exudate of Arabidopsis seeds showed a promotive activity on the growth of cockscomb and Arabidopsis itself. A new method for studying allelopathic mechanisms involving the interaction of the plant Arabidopsis thaliana (L.) Hevnh. and the fungus Neurospora crassa was suggested. Arabidopsis seed exudate and the water-soluble fraction of the exudate promoted Arabidopsis growth and reduced fungal germination, indicating that the seed exudate has a species-selective activity. Conversely, the ethylacetate-soluble fraction inhibited growth of all tested materials in the current study. These results demonstrate that the water-soluble substance(s) released from Arabidopsis seeds have species-selective activity on growth of both plants and microorganisms.     

Identification of a potent immunostimulatory oligodeoxynucleotide from Streptococcus thermophilus lacZ

Immunostimulatory sequences of oligodeoxynucleotides (ODNs), such as CpG ODNs, are potent stimulators of innate immunity. Here, we identified a strong immunostimulatory CpG ODN, which we named MsST, from the lac Z gene of Streptococcus (S.) thermophilus ATCC19258, and we evaluated its immune functions. In in vitro studies, MsST had a similar ability as the murine prototype CpG ODN 1555 to induce inflammatory cytokine production and cell proliferation. In mouse splenocytes, MsST increased the number of CD80+CD11c+and CD86+CD11c+ dendritic cells and CD4+CD25+ regulatory T cells. We also analyzed the effects of MsST on the expression of regulatory cytokines by real-time quantitative PCR. MsST was more potent at inducing interleukin-10 expression than the ODN control 1612, indicating that MsST can augment the regulatory T cell response via Toll-like receptor 9, which plays an important role in suppressing T helper type 2 responses. These results suggest that S. thermophilus , whose genes include a strong Immunostimulatory sequence-ODN, is a good candidate for a starter culture to develop new physiologically functional foods and feeds.     

Single oral β-cryptoxanthin administration increases its serum concentration and enhances peripheral blood neutrophil function in Holstein cattle

We investigated the effect of oral administration of β-cryptoxanthin (β-CRX) on its serum concentration and peripheral neutrophil functions by the chemiluminescence (CL) response in Holstein cattle. A single oral administration of β-CRX was performed for serum β-CRX concentration (0, 0.05, 0.1, or 0.2 mg/kg body weight [BW]) and for peak CL response of peripheral neutrophils (0.2 mg/kg BW). The serum β-CRX concentration was peaked on 2 days after, similar to peak CL response on 3 days after β-CRX administration. Therefore, a single oral administration of β-CRX (0.2 mg/kg BW) induces higher serum concentration and concurrently enhances bactericidal ability of peripheral neutrophils in Holstein cattle.     

A survey of antimicrobial resistance in Escherichia coli isolated from wild sika deer (Cervus nippon) in Japan

We examined the antimicrobial susceptibility of 848 Escherichia coli isolates from 237 feces samples of wild sika deer (Cervus nippon) captured between 2016 and 2019 in 39 of the 47 prefectures of Japan. Five of the 237 wild sika deer (2.1%) carried E. coli with resistance to at least one antimicrobial, and all the resistant isolates showed resistance to tetracycline. The resistant isolates contained antimicrobial resistance genes that were similar to those in E. coli derived from humans and farm animals. Although wild sika deer are not currently likely to be a source for the transmission of antimicrobial resistance in Japan, they can potentially mediate antimicrobial resistance spread by coming into contact with humans, animals, and their surroundings.     

Fecal D- and L-lactate, succinate and volatile fatty acid levels, and relationships with fecal acidity and diarrhea in neonatal calves

To clarify the significance of fecal organic anions in neonatal diarrhea, a total of 252 fecal samples (91 diarrheic, 161 normal) were collected from 136 dairy calves (including three crossbreds) less than 4 weeks old. Fecal pH, D‐ and L‐lactate, succinate and volatile fatty acid (VFA) were analyzed. In normal feces, lactate was highest and VFA was lowest at week 1 of age, and lactate progressively decreased and VFA progressively increased with advancing age. In diarrheic samples, although higher pH and lower lactate levels were confirmed at week 1, samples at weeks 3–4 showed lower pH and VFA accompanied by higher lactate of D and L‐isomers. In diarrhea, fecal butyrate was significantly lower at all stages, but succinate levels did not differ significantly. The proportion of lactate to organic anions (sum of lactate, succinate and VFA) in diarrheic feces was lower at week 1, and higher in weeks 2–4, while that of VFA to organic anions showed the opposite pattern. Strong relationships were observed between fecal pH and lactate, and VFA proportions in organic anions, though the relationship was weak in diarrhea. Most of the elevated lactate was observed in fecal samples with lower VFA. However, succinate had no relationship with VFA or lactate levels.     

ADSORPTION OF LEAD, COPPER, ZINC, COBALT, AND CADMIUM BY SOILS THAT DIFFER IN CATION-EXCHANGE MATERIALS

The adsorption of Zn²⁺, Pb²⁺, Cu²⁺, Co²⁺, and Cd²⁺ (M²⁺) by soils was measured at concentrations ranging from 10-⁷ to 10-² M in 10-³ to 10-² M CaCI₂. Exchange between Ca²⁺ and M²⁺, and solubility products [M²⁺][OH^?]² indicate that M²⁺ is not precipitated as hydroxide but is adsorbed on cation-exchange sites. The proportion of selective adsorption sites with specified values of the selectivity coefficient calculated using Ca as reference ion, increased in the order montmorillonite < humus, kaolinite, < allophane. imogolite < halloysite, iron oxides. Raising the soil pH by Ca-saturation increased both the amount and affinity of adsorption. Selectivity of adsorption increased in the order Mg, Ca < Cd, Co < Zn < Cu, Pb, and the selectivity coefficient varied from < 1 to > 10 000. The formation of the coordination complexes of heavy metal with deprotonoted OH and COOH groups as ligands is suggested as a possible mechanism of selective adsorption.     

Distribution of protein disulfide isomerase during maturation of pig oocytes

Oocyte maturation in mammals is characterized by a dramatic reorganization of the endoplasmic reticulum (ER). In mice, the ER forms accumulations in the germinal vesicle (GV) stage and distinctive cortical clusters in metaphase II (MII) of the oocyte. Multiple evidence suggests that this ER distribution is important in preparing the oocyte for Ca²⁺ oscillations, which trigger oocyte activation at fertilization. In this study, we investigated the time course and illustrated the possible functional role of ER distribution during maturation of porcine oocytes by immunostaining with protein disulfide isomerase (PDI). PDI forms clusters in the cytoplasm of oocytes. After immunostaining, PDI clusters were identified throughout the cytoplasm from the GV to metaphase I (MI) stage; however, at the MII stage, the PDI formed large clusters (1–2 µm) in the animal pole around the first polar body. PDI distribution was prevented by bacitracin, a PDI inhibitor. Our experiments indicated that, during porcine oocyte maturation, PDI undergoes a dramatic reorganization. This characteristic distribution is different from that in the mouse oocyte. Moreover, our study suggested that formation of PDI clusters in the animal pole is a specific characteristic of matured porcine oocytes.     

Occurrence of lithocholic acid in feces of healthy men

Crystalline lithocholic (3alpha-hydroxycholanic) acid was isolated from a pooled sample of feces from healthy men for the first time. This acid, which occurs in small amounts in human bile, was obtained by alcohol extraction, followed by solvent partition and chromatography. Under these conditions most of the acid was recovered in the form of its methyl ester.