Search

Fertility preservation for prepubertal cancer patients prior to oncologic treatment is an emerging issue, and non-human primates are considered to constitute suitable models due to the limited availability of human testicular tissues. However, the feasibility of spermatogonial stem cell (SSC) propagation in vitro and autologous testicular germ cell transplantation in vivo requires further exploration in monkeys. Herein, we characterized germ cells in macaque testes at 6 months (M), 18 M and 60 M of age, and effectively isolated the spermatogenic cells (including the spermatogonia) from macaque testes with high purity (over 80%) using combined approaches of STA-PUT separation, Percoll gradients and differential plating. We also generated recipient monkey testes with ablated endogenous spermatogenesis using the alkylating agent busulfan in six macaques, and successfully mimicked autologous cell transplantation in the testes under ultrasonographic guidance. The use of trypan blue led to successful intratubular injection in 4 of 4 testes. Although SSCs in culture showed no significant propagation, we were able to maintain monkey testicular germ cells with stem cell characteristics for up to 3 weeks. Collectively, these data provided meaningful information for future fertility preservation and SSC studies on both non-human primates and humans.

Plant-derived alkaloids are bioactive natural ingredients, but their contents are relatively low in plants. Therefore, efficient enrichment of alkaloids is a prerequisite for purification and further pharmacological research. In this study, an efficient and simple strategy for enrichment of steroidal alkaloid in Fritillaria was developed for the first time based on fluorinated reverse-phase stationary phase (FC8HL). Superior selectivity between alkaloids and non-alkaloids was achieved in a non-aqueous system, and a simple solvent system containing low-content additives was applied to elute alkaloids. Key parameters that affected the elution were investigated, including different types of buffer salts and optimized concentrations. The optimized elution system was then applied to selectively enrich alkaloids from five species of Fritillaria. Its practicability was further demonstrated by enrichment of alkaloids from Fritillaria cirrhosa D.Don at a preparative level. This developed method has great potential for other types of hydrophobic alkaloids. This article is protected by copyright. All rights reserved.

Functions of protein molecules in nature are closely associated with their well-defined three-dimensional structures and dynamics in body fluid. So far, many efforts have been made to reveal the relation of protein structure, dynamics, and function, but the structural origin of protein dynamics, especially for secondary structures as building blocks of conformation transition, is still ambiguous. Here we theoretically uncover the collective vibrations of elastic poly-alanine α-helices and find vibration patterns that are distinctively different over residue numbers ranging from 20 to 80. Contrary to the decreasing vibration magnitude from ends to the middle region for short helices, the vibration magnitude for long helices takes the minimum at approximately 1/5 of helix length from ends but reaches a peak at the center. Further analysis indicates that major vibrational modes of helical structures strongly depend on their lengths, where the twist mode dominates in the vibrations of short helices while the bend mode dominates the long ones analogous to an elastic Euler beam. The helix-coil transition pathway is also affected by the alternation of the first-order mode in helices with different lengths. The dynamic properties of the helical polypeptides are promising to be harnessed for de novo design of protein-based materials and artificial biomolecules in clinical treatments.

In this paper, we evaluate the incentive role of a teacher performance‐based compensation reform in rural China. Using the value‐added model widely adopted in the education literature, we first estimated the teacher effects on student academic scores with panel data of a large number of students and teachers from rural and urban schools in one county in a south‐western province of China. The estimated teachers’ value‐add was then allowed us to examine the effectiveness of the 2009 teachers’ compensation reform. We find that despite the strong intent of the performance‐based compensation reform to improve student’s academic performance, teachers’ compensations are not closely tied to teachers’ value‐add to student academic achievement. This suggests that the performance‐based compensation reform is not able to provide strong incentives for teachers to raise students’ test scores and points towards the possible problems with the design and/or implementation of the reform.

Summary Verticillium dahliae isolates are most virulent on the host from which they were originally isolated. Mechanisms underlying these dominant host adaptations are currently unknown. We sequenced the genome of V. dahliae Vd991, which is highly virulent on its original host, cotton, and performed comparisons with the reference genomes of JR2 (from tomato) and VdLs.17 (from lettuce). Pathogenicity-related factor prediction, orthology and multigene family classification, transcriptome analyses, phylogenetic analyses, and pathogenicity experiments were performed. The Vd991 genome harbored several exclusive, lineage-specific (LS) genes within LS regions (LSRs). Deletion mutants of the seven genes within one LSR (G-LSR2) in Vd991 were less virulent only on cotton. Integration of G-LSR2 genes individually into JR2 and VdLs.17 resulted in significantly enhanced virulence on cotton but did not affect virulence on tomato or lettuce. Transcription levels of the seven LS genes in Vd991 were higher during the early stages of cotton infection, as compared with other hosts. Phylogenetic analyses suggested that G-LSR2 was acquired from Fusarium oxysporum f. sp. vasinfectum through horizontal gene transfer. Our results provide evidence that horizontal gene transfer from Fusarium to Vd991 contributed significantly to its adaptation to cotton and may represent a significant mechanism in the evolution of an asexual plant pathogen.

Additive manufacturing (AM) including Stereolithography (SLA) and more recent 3D printing derivatives is an innovative manufacturing technology, where objects can be manufactured by accumulation of successive layers of materials. Such technology enables the fabrication of highly customized radar absorbing materials (RAM) and novel RAM structures. The microwave absorption, printability, complex electromagnetic parameters were measured, acrylic ester photopolymer with carbon nanotubes (CNTs) content ranging from 0.5% to 1.5% prepared with digital masking AM technology. Good dispersion and the content of CNTs have major influences on the successful preparation. The printability limit of multiwalled CNT is found to be 1.6%.The maximum absorption of 6 mm-thick composites is measured to be −15.98 dB with 1.5% CNT content. The real part ( ) of permittivity increases from 2.5 to 7 and the imaginary part ( ) of permittivity increases from 0.2 to 1.0 with the increasing content of CNTs. Frequencies, thickness, uniformly distribution of CNT and CNT content are the main factors affecting the RAM properties. The calculated reflection loss, for 12 mm-thick composites, are −7 dB, −26 dB, and −34 dB for 0.5%, 1%, and 1.5% of CNT contents, respectively, and the matching frequency shifts to lower frequencies with the increase of thickness or CNT content, which is in agreement with electromagetic theory and experiment results. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers

Male macaques produce faster sperm than male humans due to a higher pressure of sperm competition in macaques. To explore the molecular basis of this biological difference, we firstly constructed macaque and human sperm proteomes using LC-MS/MS. We then detected the positively selected genes specifically on the branch of macaque based on branch-site likelihood method. We identified 197 positively selected genes specifically on the branch of macaque that are unselected in corresponding human orthologs. These genes are highly associated with mitochondria and axoneme that directly drive sperm motility. We further compared the ultrastructural differences of the midpiece between macaque and human sperms to provide evidence for our findings using transmission electron microscopy. In conclusion, our results provide potential molecular targets for explaining the different phenotypes under sperm competition between macaques and humans, and also provide resources for the analysis of male fertility.

The function of a protein is determined by the composition of amino acids and is essential to proteomics. However, protein sequencing remains challenging due to the protein's irregular charge state and its high-order structure. Here, a proof of principle study on the capability of protein sequencing by graphene nanopores integrated with atomic force microscopy is performed using molecular dynamics simulations. It is found that nanopores can discriminate a protein sequence and even its protonation state at single-residue resolution. Both the pulling forces and current blockades induced by the permeation of protein residues are found to be highly correlated with the type of amino acids, which makes the residues identifiable. It is also found that aside from the dimension, both the conformation and charge state of the residue can significantly influence the force and current signal during its permeation through the nanopore. In particular, due to the electro-osmotic flow effect, the blockade current for the double-protonated histidine is slightly smaller than that for single-protonated histidine, which makes it possible for discrimination of different protonation states of amino acids. The results reported here present a novel protein sequencing scheme using graphene nanopores combined with nanomanipulation technology.

The objective of this study is to explore the determinants of urban at-home consumption demand for powdered milk in Guangdong province from 2007 to 2009. A double-hurdle model is used in this analysis based on survey data. The data include 8188 household distributed in 15 cities and prefectures of Guangdong province. Major findings show that the income growth of urban household, an increase in the level of education of the householder, and the different age groups within the household all have positive effects on urban at-home consumption demand for powdered milk. The prices of powdered milk have negative effects on milk consumption. Families in the Pearl River Delta consume more powdered milk than families in the other regions. The powdered milk consumption has not been significantly affected by the 2008 Chinese melamine tainted milk scandal.

A catalytic tandem arylation–cyclization approach using 2-alkynylphenyl isothiocyanates with diaryliodonium salts is described. The reaction is performed under mild conditions and thiochromeno[2,3-b]indoles are obtained in moderate to good yields. This tandem protocol involves chemoselective S-arylation, regioselective 5-endo-trig cyclization and Friedel–Crafts-type cyclization processes. Two C–C bonds, one C–S bond, and two heterocyclic rings are formed in a single step. Preliminary mechanistic studies indicate that a carbocation mechanism is involved.

This study investigated volatiles from Aquilaria sinensis (Lour.) Gilg (Thymelaeaceae) leaves that attracted Heortia vitessoides Moore (Lepidoptera: Crambidae). Volatiles from young and old A. sinensis leaves were identified and quantified by gas chromatography–mass spectrometry and gas chromatography-electroantennogram detection. Both wind tunnel bioassays and field tests were conducted to measure the attraction of adults to synthetic blends of volatiles from leaves of different maturations. Consistent electroantennographic activity was obtained for nine and three compounds from headspace collections of young and old A. sinensis leaves, respectively. Qualitative and quantitative differences were found among two odour profiles. In wind tunnel experiments, the fresh young leaves proved to be more attractive to females than old leaves. A nine-component mixture, including hexanal, limonene, 2-hexanol, octanal, (Z)-3-hexenyl acetate, (Z)-3-hexen-1-ol, nonanal, decanal, and 2,6,10-trimethyl-dodecane (with a ratio of 2:16:9:4:63:100:13:10:5) from young leaves attracted moths significantly more than the three-component mixture of nonanal, decanal, and 2,6,10-trimethyl-dodecane (with a ratio of 11:14:26) from old leaves. Further subtractive bioassays conducted in the wind tunnel showed that both the complete nine-component mixture and a subtracted four-component mixture of hexanal, (Z)-3-hexenyl acetate, nonanal, and decanal (with a ratio of 2:63:13:10) elicited equivalent responses in females. All components in the four-component blend were essential for optimal attraction. In a field trial using the nine- and four-component blends, more moths were captured using both blends than in traps baited with hexane only. Our study indicates that the odour blends of young leaves play an important role in H. vitessoides host plant recognition. The mechanisms behind host recognition and age-dependent changes in leaf chemistry are discussed.

Much effort has been focused on improving assisted reproductive technology procedures in humans and nonhuman primates (NHPs). However, the pregnancy rate after embryo transfer (ET) has not been satisfactory, indicating that some barriers still need to be overcome in this important procedure. One of the key factors is embryo–uterine synchronicity, which is little known in NHPs. The objective of this study was to investigate the available ET time window in rhesus monkey (Macaca mulatta). Eighty-two adult female rhesus monkeys were superovulated with recombinant human FSH. Ovarian phases were identified according to estrogen (E2) and progesterone (P4) levels as well as ovarian examination by ultrasonography and laparoscopy. A total of 259 embryos were transferred by the laparoscopic approach into the oviducts of 63 adult female monkeys. Ovarian phases were divided into late follicular and early luteal phases. Similar pregnancy rates (30–36.4%) were obtained from recipients receiving ET either in their late follicular or early luteal phases, regardless of embryo developmental stages. This study indicates that the available time window for ET in rhesus monkeys is from the late follicular to early luteal phases.

Caulophine is a novel fluorenone alkaloid isolated from the radix of Caulophyllum robustum Maxim. Caulophine showed high affinity for the rat myocardial cell membrane as assessed by cell membrane chromatography, suggesting that the compound may exert bioactivity in the heart. It is known that calcium plays an important role in the pathogenesis of ischaemic heart disease, and caffeine can cause calcium overload in cardiomyocytes by inducing calcium release from the sarcoplasmic reticulum. Therefore, the present study evaluated the effects of caulophine on caffeine-induced injury and calcium homeostasis in cardiomyocytes. Cardiomyocytes were pre-treated with caulophine before exposure to caffeine or potassium chloride (KCl). Cell viability was assayed using the MTT method, and lactate dehydrogenase (LDH) and malondialdehyde (MDA) were measured spectrophotometrically. Caulophine-pre-treated cardiomyocytes were incubated with Fluo-3/AM, and then caffeine or KCl was used to induce Ca2+ overload. The total intracellular Ca2+ concentration was measured by flow cytometry. Fluorescence densities of single cardiomyocytes were detected using a confocal microscope. Caulophine increased the viability of caffeine-injured cardiomyocytes and decreased LDH activity and MDA level in cardiomyocytes. Furthermore, caulophine significantly decreased the total intracellular free Ca2+ concentration and intracellular calcium release in cardiomyocytes in response to caffeine. However, the same concentrations of caulophine did not affect KCl-induced calcium influx. Our results suggest that caulophine protects cardiomyocytes from caffeine-induced injury as a result of calcium antagonism. This finding provides a basis for further study and development of caulophine as a new calcium antagonist for treating ischaemic cardiovascular diseases.

Neuropeptide S (NPS) is known to produce anxiolytic-like effects and facilitate extinction of conditioned fear. Catecholaminergic neurotransmission in the medial prefrontal cortex (mPFC) has been suggested to be crucially involved in these brain functions. In the current study, we investigated the effect of NPS on the release of dopamine and serotonin in the mPFC by in vivo microdialysis in rats. Central administration of NPS dose-dependently enhanced extracellular levels of dopamine and its major metabolite 3,4-dihydroxyphenylacetic acid, with maximal effects lasting up to 120 min. In contrast, no effect on serotonergic neurotransmission was detected. Dopamine release in the mPFC has been previously linked to modulation of anxiety states and fear extinction. The present results may thus provide a physiological and anatomical basis for the reported effects of NPS on these behaviors.

Oocytes of nonhuman primates such as rhesus monkeys are excellent models for diverse studies on developmental biology, epigenetics, human reproduction, and assisted reproductive technologies, as well as on transgenics. Such studies require numerous oocytes that can be retrieved after controlled ovarian stimulation. Currently, most primate centers use laparoscopic aspiration or laparotomy followed by aspiration to collect rhesus oocytes, although the ultrasound-guided needle aspiration is more advantageous due to reduced infection risk, less injury, and a shorter recovery period. Yet, some initial difficulties associated with the ultrasound-guided needle aspiration limit its broader application. The objective of the present study was to address these obstacles. By presenting practical solutions to the initial difficulties, results from our study show that it is possible to collect a mean number of 38 +/- 10 rhesus oocytes per hormonally stimulated female. These results compare favorably to the average number of rhesus oocytes collected using the laparoscopic approach and suggest that when initial obstacles are overcome, the ultrasound-guided oocyte retrieval represents a good alternative to more invasive approaches.

A new approach for the facile chemodivergent synthesis of tetrahydroimidazo[1,2-a]pyridines from β-ketothioamides, aldehydes and heterocyclic ketene aminals is described. In the presence of a base, an unprecedented ring-opening, tautomerization, recyclization cascade is observed and H2S eliminated tetrahydroimidazo[1,2-a]pyridines were formed in good yields. With catalytic amounts of acid, another type of different substituted tetrahydroimidazo[1,2-a]pyridines were obtained through dehydration.

A new route to prepare tetrahydrothiophene derivatives from D–A cyclopropanes and β-oxodithioesters catalyzed by Yb(OTf)3 is reported. This is the first example using β-oxodithioesters as dipolarophiles to react with D–A cyclopropanes. The method exhibits good regioselectivity.

(Arylthio)phenanthridines are prepared by tandem C—S/C—C bond—forming reaction of biaryl isothiocyanates with diaryliodonium salts using copper catalysis.

A new route to prepare pyridine derivatives via an inverse electron demand Diels—Alder/retro-Diels—Alder reaction of triazines with methyl ketones is reported.

β-Ketothioamides (KTAs) are versatile building blocks for the rapid construction of various heterocyclic compounds. In the past decade, a number of successful reactions based on KTAs have been developed for the construction of heterocyclic skeletons under mild conditions. This minireview focuses on the annulation reactions of KTAs with dielectrophilic or dinucleophilic reagents. Multicomponent reactions using KTAs to construct various heterocycles are also the major contents in this review.