Number and Nuclear Localisation of Nucleoli in Mammalian Spermatocytes

In seven mammalian species, including man, the position and number of nucleoli in pachytene spermatocyte nuclei were studied from electron microscope (EM) nuclear sections or bivalent microspreads. The number and position of the nucleolar organiser regions (NORs) in mitotic and meiotic chromosomes were also analysed, using silver staining techniques and in situ hybridisation protocols. The general organisation of pachytene spermatocyte nucleoli was almost the same, with only minor morphological differences between species. The terminal NORs of Thylamys elegans (Didelphoidea, Marsupialia), Dromiciops gliroides (Microbiotheridae, Marsupialia), Phyllotys osgoodi (Rodentia, Muridae) and man, always gave rise to peripheral nucleoli in the spermatocyte nucleus. In turn, the intercalated NORs from Octodon degus, Ctenomys opimus (Rodentia, Octodontidae) and Chinchilla lanigera (Rodentia, Cavidae), gave rise to central nucleoli. In species with a single nucleolar bivalent, just one nucleolus is formed, while in those with multiple nucleolar bivalents a variable number of nucleoli are formed by association of different nucleolar bivalents or NORs that occupy the same nuclear peripheral space (Phyllotis and man). It can be concluded that the position of each nucleolus within the spermatocyte nucleus is mainly dependent upon: (1) the position of the NOR in the nucleolar bivalent synaptonemal complex (SC), (2) the nuclear pathway of the nucleolar bivalent SC, being both telomeric ends attached to the nuclear envelope, and (3) the association between nucleolar bivalents by means of their NOR-nucleolar domains that occupy the same nuclear space. Thus, the distribution of nucleoli within the nuclear space of spermatocytes is non-random and it is consistent with the existence of a species-specific meiotic nuclear architecture.     

Computational Characterization of Exogenous MicroRNAs that Can Be Transferred into Human Circulation

MicroRNAs have been long considered synthesized endogenously until very recent discoveries showing that human can absorb dietary microRNAs from animal and plant origins while the mechanism remains unknown. Compelling evidences of microRNAs from rice, milk, and honeysuckle transported to human blood and tissues have created a high volume of interests in the fundamental questions that which and how exogenous microRNAs can be transferred into human circulation and possibly exert functions in humans. Here we present an integrated genomics and computational analysis to study the potential deciding features of transportable microRNAs. Specifically, we analyzed all publicly available microRNAs, a total of 34,612 from 194 species, with 1,102 features derived from the microRNA sequence and structure. Through in-depth bioinformatics analysis, 8 groups of discriminative features have been used to characterize human circulating microRNAs and infer the likelihood that a microRNA will get transferred into human circulation. For example, 345 dietary microRNAs have been predicted as highly transportable candidates where 117 of them have identical sequences with their homologs in human and 73 are known to be associated with exosomes. Through a milk feeding experiment, we have validated 9 cow-milk microRNAs in human plasma using microRNA-sequencing analysis, including the top ranked microRNAs such as bta-miR-487b, miR-181b, and miR-421. The implications in health-related processes have been illustrated in the functional analysis. This work demonstrates the data-driven computational analysis is highly promising to study novel molecular characteristics of transportable microRNAs while bypassing the complex mechanistic details.     

Total and Regional Fat Distribution is Strongly Influenced by Genetic Factors in Young and Elderly Twins

Objective: Indirect estimates of obesity such as BMI seem to be strongly influenced by genetic factors in twins. Precise measurements of total and regional fat as determined by direct techniques such as DXA scan have only been applied in a few twin studies. The aim of the present study was to estimate the heritability (h²) of total and regional fat distribution in young and elderly Danish twins. Research Methods and Procedures: Monozygotic (108) and dizygotic (88) twins in two age groups (25 to 32 and 58 to 66 years) underwent anthropometric measurements and DXA scans. Intraclass correlations and etiologic components of variance were estimated for total and regional fat percentages using biometric modeling. Results: The intraclass correlations demonstrated higher correlations for all fat percentages among monozygotic twins as compared with dizygotic twins. The biometric modeling revealed a major genetic component (h²) of total (h²_young = 0.83, h²_elderly = 0.86) and regional fat percentages (trunk, h²_young = 0.82, h²_elderly = 0.85; lower body, h²_young = 0.83, h²_elderly = 0.81; and trunk/lower body, h²_young = 0.83, h²_elderly = 0.71) in both the young and elderly twins. Discussion: The h² estimates emphasize that body fat and distribution as determined by DXA scan are under extensive genetic control.     

植物成熟microRNA转录后修饰与降解的研究进展

microRNA(miRNA)是一类长度为20–24 nt的内源小RNA,广泛存在于各种植物体内,参与调控植物器官的形态建成、激素应答、逆境胁迫和营养代谢等一系列过程。虽然miRNA生物合成和功能研究已取得了很大进展,但关于植物成熟miRNA的转录后修饰和降解的研究却报道较少。一方面miRNA如同其它RNA存在半衰期,其降解对于调控细胞内miRNA含量起重要作用,从而调控植物的生长发育或胁迫响应等过程;另一方面,成熟miRNA存在转录后修饰,可影响miRNA的稳定性,最终影响其活性。该文着重从植物成熟miRNA的转录后修饰和降解等方面进行了综述。     

家蚕肠道环境对外源纤维素酶活力稳定性影响的研究

纤维素酶对家蚕消化桑叶纤维素起重要生理作用,本试验研究了不同温度、pH对外源纤维素酶活力的影响及纤维素酶的热稳定性与pH稳定性,同时在模拟家蚕肠道环境条件下,研究了纤维素酶活力的稳定性。结果表明：所选的外源纤维素酶在家蚕肠液中的最适催化温度为30℃左右,最适pH为8．0左右;酶在家蚕体温范围内具有较好的稳定性,在pH8．0-10．0范围内酶活力较稳定;模拟家蚕肠道环境条件下酶活力稳定性实验表明,在80min时间内,纤维素酶能够保持较高的活力而发挥生物活性。     

Scale of Management for Mature Male White-Tailed Deer as Influenced by Home Range and Movements

Abstract: The scale at which populations use landscapes influences ecological processes and management. We used dispersal and home-range data of 3 age groups of male white-tailed deer (Odocoileus virginianus) to determine the scale at which management will be effective. Home-range size at 5.5 years of age (182 ha ± 24.9 SE) was 56% smaller (P < 0.001) than home-range size of the same 13 males as yearlings (416 ± 59.4 ha). Percent overlap of yearling and 5.5-year-old home ranges was 62.7 6 10.3% (n = 13). Distance between home-range centers of yearling and mature deer was 1,264.9 ± 407.4 m, including 3 deer that dispersed after 2.5 years of age. Average 95% fixed-kernel home-range size was 207.4 ± 20.4 ha and 225.7 ± 30.1 ha for all mature males in years 1 and 2 of our study, respectively. We found that properties >10,000 ha were needed to manage >50% of original yearling males found on the property, whereas properties of 4,500 ha would maintain 50% of original middle-aged (2.5-4.5 yr of age) and mature males (≥4.5 yr of age). Movements after dispersal were minimal, with deer shifting their center of activity <600 m and <350 m each year for middle-aged and mature males, respectively. These data could be used by managers developing management plans, recommending harvest rates, and interpreting harvest data of male white-tailed deer and by biologists attempting to understand ecological processes such as spread of disease.     

Regulation of Coagulation Factor XI Expression by MicroRNAs in the Human Liver

High levels of factor XI (FXI) increase the risk of thromboembolic disease. However, the genetic and environmental factors regulating FXI expression are still largely unknown. The aim of our study was to evaluate the regulation of FXI by microRNAs (miRNAs) in the human liver. In silico prediction yielded four miRNA candidates that might regulate FXI expression. HepG2 cells were transfected with miR-181a-5p, miR-23a-3p, miR-16-5p and miR-195-5p. We used mir-494, which was not predicted to bind to F11, as a negative control. Only miR-181a-5p caused a significant decrease both in FXI protein and F11 mRNA levels. In addition, transfection with a miR-181a-5p inhibitor in PLC/PRF/5 hepatic cells increased both the levels of F11 mRNA and extracellular FXI. Luciferase assays in human colon cancer cells deficient for Dicer (HCT-DK) demonstrated a direct interaction between miR-181a-5p and 3′untranslated region of F11. Additionally, F11 mRNA levels were inversely and significantly correlated with miR-181a-5p levels in 114 healthy livers, but not with miR-494. This study demonstrates that FXI expression is directly regulated by a specific miRNA, miR-181a-5p, in the human liver. Future studies are necessary to further investigate the potential consequences of miRNA dysregulation in pathologies involving FXI.     

Deconstructing Stepwise Fate Conversion of Human Fibroblasts to Neurons by MicroRNAs

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Losses of Total Phosphorus from Watersheds Influenced by Various Human Activity

In territories without settlements, major livestock production or industry, and from territories devoted to row-crop agriculture (diffuse pollution sources), the annual mean concentrations of total phosphorus compounds in waterways were found to be 17 to 43 μg · 1⁻¹ P. Where there are point or hybrid pollution sources in watersheds, the annual average concentrations vary from 56 to 410 μg · 1⁻¹ P. It was found that annual average total phosphorus concentration values obtained from three-week sampling intervals can be used to show the presence of diffuse, hybrid and point pollution sources. The main sources of the high and permanent total phosphorus concentrations were densely populated areas, industrial works, agriculture, inadequately managed farms and disposal sites for solid and liquid wastes.     

Composition, Properties and Localisation of Pectins in Young and Mature Cells of the Mung Bean Hypocotyl

Two pectic fractions were extracted along the growth gradientof the mung bean hypocotyl. The first one (PF₁) contained pectinssoluble in boiling water and characterized by low uronic acids/cationsratio, high esterification degree and high neutral sugars/acidicsugars ratio. The second one (PF₂) contained pectins insolublein boiling water characterized by high uronic acids/cationsratio, low esterification degree, very low neutral sugar contentand a high selectivity for calcium. Water soluble pectins werepresent in all the wall area whereas the other ones were detectedmainly in the middle lamella. The PF₁/PF₂ ratio was high infast growing tissues but low in mature, slowly growing tissues.The development of the cell wall exchange properties along thegrowth gradient was related to the changes observed in the PF₁/PF₂balance. (Received July 31, 1985; Accepted January 20, 1986)     

Localisation and Function of the Endocannabinoid System in the Human Ovary

Background

Although anandamide (AEA) had been measured in human follicular fluid and is suggested to play a role in ovarian follicle and oocyte maturity, its exact source and role in the human ovary remains unclear.

Methods and Findings

Immunohistochemical examination of normal human ovaries indicated that the endocannabinoid system was present and widely expressed in the ovarian medulla and cortex with more intense cannabinoid receptor 2 (CB2) than CB1 immunoreactivity in the granulosa cells of primordial, primary, secondary, tertiary follicles, corpus luteum and corpus albicans. The enzymes, fatty acid amide hydrolase (FAAH) and N-acyclphosphatidylethanolamine-phospholipase D (NAPE-PLD), were only found in growing secondary and tertiary follicles and corpora lutea and albicantes. The follicular fluid (FF) AEA concentrations of 260 FF samples, taken from 37 infertile women undergoing controlled ovarian hyperstimulation for in vitro fertilisation and intracytoplasmic sperm injection with embryo transfer, were correlated with ovarian follicle size (P = 0.03). Significantly higher FF AEA concentrations were also observed in mature follicles (1.43±0.04 nM; mean±SEM) compared to immature follicles (1.26±0.06 nM), P = 0.0142 and from follicles containing morphologically assessed mature oocytes (1.56±0.11 nM) compared to that containing immature oocytes (0.99±0.09 nM), P = 0.0011. ROC analysis indicated that a FF AEA level of 1.09 nM could discriminate between mature and immature oocytes with 72.2% sensitivity and 77.14% specificity, whilst plasma AEA levels and FF AEA levels on oocyte retrieval day were not significantly different (P = 0.23).

Conclusions

These data suggest that AEA is produced in the ovary, is under hormonal control and plays a role in folliculogenesis, preovulatory follicle maturation, oocyte maturity and ovulation.     

血清后人血管平滑肌细胞表型转化与microRNAs表达间关系的研究

目的:研究去血清诱导人血管平滑肌细胞发生表型转化与microRNAs表达间的关系。方法:采取人血管平滑肌细胞克隆株HITASY,培养人血管平滑肌细胞(VSMCs)。用去血清的方法处理人血管平滑肌细胞,使VSMCs由去分化表型向分化表型转化,通过蛋白印迹法观察平滑肌细胞中分化标记物蛋白的变化,同时用实时定量PCR法检测细胞中相关microRNA的表达。结果:①去血清处理组与无去血清处理组比较,平滑肌细胞分化标记物(SM-α-actin、calponin)表达显著性增加,而通过SM-α-actin、calponin的蛋白表达量显著增加,提示血管平滑肌细胞向分化表型转化(P0.05);②同时去血清处理组与无去血清处理组比较,Mir-649、Mir-944表达量显著增加,Mir-140、Mir-361表达量显著减少(P0.05)。结论:Mir-649、Mir-944、Mir-140、Mir-361在血管平滑肌细胞表型转化中有关键性作用。     

Staining of Small Lymphoid Nucleoli in Paraffin Sections by Aniline-Azure B

To see small lymphoid nucleoli clearly in 1-2 μ paraffin sections, the staining of contiguous chromatin masses in the nucleus was suppressed by a hydrolysis-aniline blocking sequence, which produces aldehyde from DNA, and attaches aniline to that aldehyde to make a diphenamine base, thus reducing the acidity of the chromatin and its affinity for basic dyes. Nucleolar RNA remains fully stainable by azure B, because the hydrolysis used does not produce aldehyde groups in it, to allow aniline attachment. Technique: Hydrolyse the 10% formol-saline fixed, deparaffinised 1-2 μ section for 4.5-5.0 min in 10% (v/v) HCl in tetra-hydrofuran at 39-40 C, rinse in water, and treat at room temperature in 10% (v/v) aniline in acetic acid for 10 min. Stain 2-4 hr with freshly prepared 0.1% azure B in a 1:10 dilution of tris buffer at pH 7.0. Rinse, blot off excess water, pass through acetone and xylene to a polystyrene mounting. DNA stains pale green to colourless; nucleolar and cytoplasmic RNA, blue.     

Prey Escape Direction is Influenced by the Pivoting Displays of Flush-Pursuing Birds

Painted redstart, Myioborus pictus, and its congeners in Central and South America, belong to a small fraction of insectivorous flush‐pursuing birds. Unlike most of the small insectivorous birds, which glean prey from substrates, the flush pursuers spread and pivot their conspicuously patterned tails and wings. This display triggers prey escape flights which are hypothesized to occur through visual stimulation of prey escape circuits [giant descending neuron cluster (GDNC) in Diptera] sensitive to the looming motion of an approaching bird, translational motion of a pivoting body with widely spread tail and contrast of the white‐black plumage pattern. In this paper, data from field observations of redstarts and experiments with bird models show an increase in the frequency of prey escapes away from the strong visual stimulation of an open tail, and in the direction opposite to that of the horizontal translational motion present in the pivots. We discuss how the effect on prey escape direction may enhance prey interception capabilities of redstarts during aerial pursuits. Combined with an earlier study the results show that, unlike the movements of typical gleaner–foragers, the flush displays by redstarts affect prey escape direction in a manner that may facilitate prey tracking and capture by birds. Because the GDNs, which mediate escape initiation, are not sensitive to motion direction, we hypothesize that other neurons, in addition to the GDNs, are involved in influencing the direction of escape responses.