胡萝卜贮藏过程中电容与新鲜度的关系研究

新鲜植物组织的介电特性与其新鲜度具有一定的相关性,本文采用两平行平板电极,对胡萝卜组织贮藏过程中介电特性的特征值之一电容与新鲜度的关系进行了研究,结果表明：随着胡萝卜的贮藏时间的延长,果肉组织表现为硬度增加、光泽消退、表皮皱缩、新鲜度下降;在0.1～100 kHz测试频率段内,胡萝卜的电容与新鲜度的判定指标色泽、硬度、水分含量之间具有明显的线性相关性。因此,可以根据胡萝卜电容值的变化来评价其新鲜度,为蔬菜无损自动化鲜度检测提供理论依据。     

The transition time from the juvenile phase to the adult phase differs in soybean cultivars ‘Enrei’ and ‘Peking’

Plants develop juvenile phase to adult phase in vegetative stage. Although soybean is a very important crop worldwide, there has been only one study of the juvenile–adult phase change. In this study, we determined that the juvenile–adult phase change occurred at different stages in two soybean cultivars that differ in their photosensitivity. Cultivar ‘Enrei’ (E1e2e3E4) is weakly photosensitive and cultivar ‘Peking’ (E1E2E3E4) is strongly photosensitive. In ‘Enrei’, the leaf size gradually increased at a constant leaf position regardless of the difference in day length. In ‘Peking’ plants transferred to short‐day conditions at several leaf development stages, leaf size gradually increased at different leaf positions. Expression of miR156 by ‘Enrei’ transferred to short‐day conditions had nearly the same pattern as that of ‘Enrei’ grown under long‐day conditions. In ‘Peking’, the expression of miR156 had different patterns in younger leaves of plants subjected to either a short‐day treatment or long‐day conditions. These results indicate that the E2 and E3 loci that regulate photosensitivity also regulate the expression of miR156 and the juvenile–adult phase change in soybean.     

Exfoliation rate of mammary epithelial cells in milk on bovine mastitis caused by Staphylococcus aureus is associated with bacterial load

The exfoliation rate of mammary epithelial cells (MECs) in milk is affected by physiological, breeding and environmental factors. Little is known about the relationship between the MEC exfoliation into milk and mammary‐infected Staphylococcus aureus (S. aureus) load on bovine mastitis caused by S. aureus. The aim of this study was to investigate the relationship between S. aureus load and the proportion of MEC exfoliation in milk using five substantial bovine mastitis models. In 64 randomly extracted milk samples from udders at 3–21 days after S. aureus infusion, there were various samples with different numbers of S. aureus counts and somatic cell counts. No significant correlations were found between the S. aureus counts and somatic cell count (r = 0.338). In contrast, a significant correlation was noted between S. aureus counts and the proportion of cytokeratin‐positive cells in the milk from the infused udders (r = 0.734, P < 0.01). In conclusion, the increasing MEC exfoliation rate in milk from mastitis udders caused by S. aureus may contribute to reduced milk yield.     

Kazakhstani native cattle reveal highly divergent mtDNA from Bos taurus and Bos indicus lineages with an absence of Bos indicus Y chromosome

Kazakhstan is the largest landlocked country and contains two important propagation routes for livestock from the Fertile Crescent to Asia. Therefore, genetic information about Kazakhstani cattle can be important for understanding the propagation history and the genetic admixture in Central Asian cattle. In the present study, we analyzed the complete mtDNA D‐loop sequence and SRY gene polymorphism in 122 Kazakhstani native cattle. The D‐loop sequences revealed 79 mitochondrial haplotypes, with the major haplogroups T and I. The Bos taurus subhaplogroups consisted of T (3.3%), T1 (2.5%), T2 (2.5%), and T4 (0.8%) in addition to the predominant subhaplogroup T3 (86.9%), and the Bos indicus subhaplogroup of I1 (4.1%). Subsequently, we investigated the paternal lineages of Bos taurus and Bos indicus, however, all Kazakhstani cattle were shown to have Y chromosome of Bos taurus origin. While highly divergent mtDNA subhaplogroups in Kazakhstani cattle could be due to the geographical proximity of Kazakhstan with the domestication center of the Fertile Crescent, the absence of Bos indicus Y chromosomes could be explained by a decoupling of the introgression dynamics of maternal and paternal lineages. This genetic information would contribute to understanding the genetic diversity and propagation history of cattle in Central Asia.     

Distribution of recesses in the olfactory organ of African lungfish Protopterus aethiopicus

In the olfactory organ of lungfish, recesses at the bases of lamellae comprise sensory and nonsensory epithelia. The sensory epithelium of the recesses, the recess epithelium, is distinguished from the olfactory epithelium covering the lamella by the absence of ciliated olfactory receptor cells. Therefore, it has been suggested that the recess epithelium is a primordium of the vomeronasal organ of tetrapods. However, developmental changes in the number and distribution of recesses in the olfactory organ of lungfish were unknown. We examined four Protopterus aethiopicus specimens of body lengths 215–800 mm to determine the localization of recesses in their olfactory organs. Histological examination showed recesses at the bases of lamellae in all individuals examined. The recesses were localized mainly in the medial and caudal parts of the olfactory organs, especially in juveniles. Compared to smaller fish, larger fish had a larger number of recesses, distributed more broadly in their olfactory organs. Significance of the recess localization and its relationship to the function of lungfish olfactory organ warrants further investigation.     

Hydroxyanthraquinones in soil

(1) Seven hydroxyanthraquinone pigments were separated from Sochiken soil 1 (Kuroboku soil). Chrysotalunin, chrysophanoi, chrysazin, and skyrln were identified by spectroscopy and co-chromatography with authentic compounds. The presence of oxyskyrin was presumed by spectroscopy and color reactions.

(2) A homologue of 4,9-dihydroxyperylene-3, 10-quinone was also detected.

(3) The amounts of hydroxyanthraqulnones in eight soils of different types were determined by colorimetry using chrysotalunin as a standard pigment. Their amounts varied from 3 to 11 ppm.

(4) The main pigment extracted from most soils was chrysotalunin, though it was not detected in Miyahara, Higashiyama, and Kisokoma soils.     

Hd3a protein is a mobile flowering signal in rice

Florigen, the mobile signal that moves from an induced leaf to the shoot apex and causes flowering, has eluded identification since it was first proposed 70 years ago. Understanding the nature of the mobile flowering signal would provide a key insight into the molecular mechanism of floral induction. Recent studies suggest that the Arabidopsis FLOWERING LOCUS T (FT) gene is a candidate for encoding florigen. We show that the protein encoded by Hd3a, a rice ortholog of FT, moves from the leaf to the shoot apical meristem and induces flowering in rice. These results suggest that the Hd3a protein may be the rice florigen.     

Partial cDNA sequence of a relaxin‐like factor (RLF) receptor,LGR8 and possible existence of the RLF ligand‐receptor system in goat testes

Relaxin‐like factor (RLF), also known as insulin‐like factor 3 (INSL3), is produced by testicular Leydig cells, but its specific receptor LGR8 (leucine‐rich repeat family of G‐protein‐coupled receptor 8) has not been identified in goats. This study aimed to identify complementary DNA (cDNA) sequences of goat LGR8, and characterize the expression of both RLF and LGR8 in goat testes by RT‐PCR and immunohistochemistry. Testes were collected from immature (3‐month‐old) and mature (24‐month‐old) Saanen goats, and partial cDNA sequences of the goat homologue of human LGR8 were identified. The sequence encoded a reduced peptide sequence of 167 amino acids, which corresponded to transmembrane regions 2 through 5, followed by the beginning of intracellular loop 3 of human LGR8. Expression of both LGR8 and RLF genes was drastically increased in mature testes compared with immature ones. Although RLF protein was restricted to Leydig cells, LGR8 protein was detected in both Leydig cells and seminiferous epithelial cells (possibly germ cells and Sertoli cells). These results reveal a possible existence of the RLF‐LGR8 ligand‐receptor system within the goat testis, suggesting that RLF may play a role in testicular function through LGR8 on Leydig cells and seminiferous epithelial cells in an autocrine and/or paracrine manner.