Distribution of α-D-mannose residue on zona pellucida and its role(s) in fertilization in pigs

The present study aims to identify the distribution of α-D-mannose residues on zona pellucida (ZP) and their role(s) in fertilization in pigs. In experiment 1, in vitro matured pig oocytes were freed from cu- mulus cells and treated with fluorescein isothiocyanate-labelled Lens culinaris (FITC-LCA), a D-mannose specific binding lectin. After 30 min of treatment, LCA bound evenly throughout the ZP with strong fluorescence. In experiment 2, when LCA-treated oocytes were used for in vitro fertilization, the number of sperm bound to ZP was significantly decreased, and sperm penetration was almost com- pletely blocked. In experiment 3, polysaccharide mannan was added to the in vitro fertilization medium as a competitive inhibitor. Both the number of sperm bound to ZP and the rate of fertilized oocytes were significantly reduced in the mannan-treated group compared with the control group. In experiment 4, spermatozoa were incubated with mannan in vitro. The number of acrosome-reacted spermatozoa was evidently increased in a time-dependent manner during the incubation. These results suggest that α-D-mannose residues presenting on pig ZP might be an important component of sperm receptor and might induce sperm acrosome reaction and thus facilitate the sperm penetration into the ZP.     

草鱼、中华鳖造血器官和血细胞凝集素结合部位的观察

Lectin binding patterns in the hemopoietic organs and blood cells of Grass carp ( Ctenopharyngodon idellus ), Chinese soft shelled turtle ( Trionyx sinensis) were observed with two affinity histochemical methods, ABC staining and fluorescence bound lectin staining. Concanavalin (ConA), Phytohemagglutinin (PHA), Pokeweed agglutinin (PWM) and Lipopolysaccharide (LPS) binding sites were distributed mainly on the plasma membrane of lymphocytes. ConA, PHA binding sites were distributed in thymus, cordic structure of head kidney and scatterly spleenic tissue of C. idellus, also in thymus and periellipsoidal lymphatic sheaths and marginal region of T. sinensis. PWM, LPS binding sites were scatterly distributed in cordic structure of head kidney of C. idellus, spleenic tissue of C. idellus and T. sinensis, but positive cell groups were not obvious. ConA, PHA and PWM positive percents of lymphocytes in blood smears were repectively 36%～41%, 33%～37%, 38%～43% in C. idellus and 37%～48%, 36%～45%, 44%～53% in T. sinensis, but percents of positive cells were repectively 15%～18%, 14%～17%, 9%～12% in imprints of head kidney of C. idellus.     

Unordered arrangement of chromosomes in the nuclei of chicken spermatozoa

The arrangement of chromosomes in the elongated sperm nuclei of chicken was studied using fluorescence in situ hybridization with probes specific for telomeres of all chromosomes, a microchromosome, the long arm of chromosome 6, the large heterochromatic block on the Z-chromosome, and the same heterochromatic block plus subtelomeric sites on macrochromosomes 1–4. The positions of all probes vary from one sperm to another. No order in chromosome arrangement is apparent. It is suggested that large chromosome size and small chromosome number correlate with constant positions of chromosomes and vice versa. Based on the known quantity of repetitive units of the repeat on the Z-chromosome, the degree of compaction of chromatin in the chicken sperm nucleus is estimated as ca 0.7 Mb/μm. As judged from the length of the heterochromatic region of the Z-chromosome at the lampbrush stage, the total length of the Z-chromosome in mature sperm is 2.5–4 times that of the sperm nucleus. Received: 15 December 1997; in revised form: 24 March 1998 / Accepted: 14 April 1998     

Refuge size variation and potential for sperm competition in Wellington tree weta

Ecological variation in resources can in flue nee the distributi on and en counter rates of potential mates and competitors and, con sequently, the opport unity for sexual selection. Factors that influence the likelihood that females mate multiply could also affect the potential for sperm competition. In Wellington tree weta (Hemideina crassidens, plural "weta"), the size of tree cavities (called galleries) used as refuges affects weta distribution and thus the opport unity for sexual selection and selection on male weaponry size. We examined the predicted effects of gallery size and male weap onry size on the potential for sperm competition. We asked if gallery size in flue need the potential for multiple mating by females and potential for sperm competition, if male weaponry size was associated with relative expected sperm competition intensity (SCI), and if estimated male mating success was correlated with pote ntial SCI. To qua ntify relative competitive envir on merits of males, we created and analyzed networks of potential competitors based on which males could have mated with the same females. We found that small galleries had higher potential for female multiple mating and higher potential for sperm competition. Size of male weaponry was not associated with expected relative SCI. Regardless of gallery size, males with more potential mates were expected to face lower expected relative sperm competition. Thus, in this system, variation in the size of available refuges is likely to in flue nee the pote ntial for sperm competiti on, in a way that we might expect to in crease variation in overall reproductive success.     

Characterization of rtSH3p13 gene encoding a development protein involved in vesicular traffic in spermiogenesis

A cDNA, designated as rtSH3pl3, was isolated from a rat testis cDNA library. It consists of 1463 bp nuclear acids,which encodes a protein of 312 amino acids and was assigned the GenBank accession number AF227439. The deduced rtSH3p13 protein is a truncated isoform of SH3pl3 as a result of mRNA alternative splicing. It is mainly expressed in the rat testis, detected in spermatids at the steps 8-19 of spermiogenesis, and found around the acrosome. During postnatal development, rtSH3pl 3 appears on day 18 and reaches maximum on day 60. Further experimental results suggested that rtSH3pl3 forms a complex with activated epidermal growth factor receptor (EGFR) and interacts with synaptojanin I. Surprisingly, similar to SH3 domain, the V region of rtSH3pl3 also inhibits endocytosis in CHO cells.Our results reveal a link between an rtSH3p13-synaptojanin-clathrin complex-mediated formation of pits and the process of spermiogenesis.     

蟦科昆虫地理分布研究初探

In the present paper,the origin of the fa-mily Perlidae and the distribution characters of the tribe and the subfamily were summarized and analyzed.Based on the distribution of the genera in the world,the eight distribution types of the genera were divided.In addition,the distribution characters of the Perlidae in China were also probed preliminarily.So far two subfamilies,four tribe and twenty genera have been found in China.Ten of them,of which three genera are endemic to China,are the Oriental genera;one Palaearctic genus;three Oriental-Palaearctic genera;one Oriental-Nearctic genus;four Oriental-Palaearctic-Nearctic genera and one Oriental-Palaearctic-Nearctic-Afrotropical genus.Moreover,the main distribution character of Chinese Perlidae is that most of the species distribute Central China region,South China region and Southwest China region.The Central China region centralizes the distribution and the break of the perlid species,and made the dispersal for the others regions.     

Attractive males have faster sperm in three-spined sticklebacks Gasterosteus aculeatus

Recent studies have revealed that sexually selected traits may signal sperm quality and hence male fertilisation ability. There is also evidence that the expression of male sexual ornamentation and associated sperm characteristics depend on an indi- vidual＇s ability to cope with oxidative stress. Carotenoids are known for their antioxidant properties and carotenoid-based orna- ments might represent honest signals as these pigments can be traded offbetween the investment in sexual ornamentation, sperm function as well as immune response. In this study, we examined the relationship between sexual ornamentation （breeding colo- ration） and sperm characteristics （e.g., velocity and morphology） in the three-spined stickleback Gasterosteus aeuleatus, an ex- ternally fertilising fish species, in which sperm competition commonly occurs. During the breeding season males are sperm limi- ted and develop a conspicuous carotenoid-based coloration, which is under strong pre-copulatory sexual selection due to female mate choice and male-male competition. The results of the present study show that the expression of stickleback male breeding coloration is significantly positively associated with the linearity of sperm movement, whereas sperm morphology （head length to tail length ratio） is significantly negatively related to the trajectory of sperm movement. Moreover, there is some support for the phenotype-linked fertility hypothesis as the intensity of male red breeding coloration is significantly positively correlated with sperm velocity, which is supposed to be an important determinant of fertilisation success in external fertilisers, indicating the honesty of the sexually selected nuptial red coloration.     

Effect of Salinity on the Composition, Number and Size of Epidermal Cells along the Mature Blade of Wheat Leaves

Salinity inhibits leaf growth in association with changes in cell size. The objective of this study was to determine the spatial distributions of the composition, number and dimensions of epidermal cells in the mature blades of leaf four of wheat seedlings under saline conditions. Plants were grown in loamy soil either with or without 120 mmol/L NaCl in a growth chamber, and harvested after leaf four was fully developed. The results of the spatial distribution analyses of width along the blade showed that salinity not only reduced the width of the leaf blade, but that it also altered the distribution pattern of blade width along the leaf axis. The reduction in the final size of the leaf blade was associated with a reduction in the total number of epidermal cells and in their widths and lengths. This study also revealed the spatial effects of salinity on the blade and epidermal cell dimensions along the leaf axis. In particular, salinity inhibited the total cell number for interstomatal, sister and elongated cells, implying that cell division in wheat leaves is inhibited by salinity. However, the lengths of interstomatal cells were not affected by salinity （unlike those for the sister and elongated cells）, suggesting the relative contributions of cell length and numbers to the reduction in the final length of the blade under salinity is dependent on cell type.     

Knights in Action： Lectin Receptor-Like Kinases in Plant Development and Stress Responses

The Receptor-Like Kinase （RLK） is a vast protein family with over 600 genes in Arabidopsis and 1100 in rice. The Lectin RLK （LecRLK） family is believed to play crucial roles in saccharide signaling as well as stress perception. All the LecRLKs possess three domains： an N-terminal lectin domain, an intermediate transmembrane domain, and a C-terminal kinase domain. On the basis of lectin domain variability, LecRLKs have been subgrouped into three subclasses： L-, G-, and C-type LecRLKs. While the previous studies on LecRLKs were dedicated to classification, comparative structural analysis and expression analysis by promoter-based studies, most of the recent studies on LecRLKs have laid special emphasis on the potential of this gene family in regulating biotic/abiotic stress and developmental pathways in plants, thus mak- ing the prospects of studying the LecRLK-mediated regulatory mechanism exceptionally promising. In this review, we have described in detail the LecRLK gene family with respect to a historical, evolutionary, and structural point of view. Furthermore, we have laid emphasis on the LecRLKs roles in development, stress conditions, and hormonal response. We have also discussed the exciting research prospects offered by the current knowledge on the LecRLK gene family. The multitude of the LecRLK gene family members and their functional diversity mark these genes as both interesting and worthy candidates for further analysis, especially in the field of crop improvement.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.