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The key process of sexual reproduction is the successful fusion of the sperm and egg cell. Distinct from dynamic and flagellated animal sperm cells, higher flowering plant sperm cells are immotile. Therefore, plants have evolved a novel reproductive system to achieve fertilization and generate progenies. Plant sexual reproduction consists of multiple steps, mainly including gametophyte development, pollen-pistil recognition, pollen germination, double fertilization and postfertilization. During reproduction, active production, consumption and recycling of cellular components and energy are critically required to achieve fertilization. However, the underlying machinery of cellular degradation and turnover remains largely unexplored. Autophagy, the major catabolic pathway in eukaryotic cells, participates in regulating multiple aspects of plant activities, including abiotic and biotic stress resistance, pathogen response, senescence, nutrient remobilization and plant development. Nevertheless, a key unanswered question is how autophagy regulates plant fertilization and reproduction. Here, we focus on comparing and contrasting autophagy in several key reproductive processes of plant and animal systems to feature important distinctions and highlight future research directions of autophagy in angiosperm reproduction. We further discuss the potential crosstalk between autophagy and programmed cell death, which are often considered as two disconnected events in plant sexual reproduction.

Primary bovine mammary epithelial cells (BMECs) are not ideal models for long-term studies of lactation mechanisms because these cells in a monolayer culture system cannot be polarized to simulate the physiological functions in vitro. We investigate the effects of different culture models and karyotypes on casein expression in a three-dimensional (3D) culture system. The immortalized cells' karyotypes were analyzed at passages 10, 20, 30 and 40 to detect the effects of chromosome stability. Western blotting examined that whether or not the immortalized cells at passages 5, 10, 20, 30, 40 and 50 could induce expression of casein in a 3D culture system. The proper polarization of the acinar structures was monitored. BMECs were successfully immortalized. The cell karyotype at passage 30 remained at 60 chromosomes and the average value was 57.1 ± 0.40 after passage 40. The polarized protein's levels were up-regulated in 3D culture compared to 2D culture. Expression of αs1, β and κ-casein could be detectable in a passage range in 3D culture. Expression of αs2-casein was undetectable in all experimental groups. However, all casein expressions were barely detectable in traditional 2D culture system. Therefore, 3D culture system is an important tool for the long-term study of lactation mechanisms in vitro.

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) is widely used in diagnosis and research to determine specific mRNA expressions in cells. As RT-qPCR applications increase, it's necessary to provide undergraduates hands-on experience of this modern technique. Here, we report a 3-week laboratory exercise using RT-qPCR to demonstrate the light-dependent expressions of AtRBCS1A and AtRBCS3B genes encoding two Arabidopsis thaliana small subunits of the ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). In the first week, students purified and quantified total RNA from leaves of A. thaliana pretreated in the dark for 96 hr and untreated controls. In the second week, RNA samples were separated by formaldehyde gel electrophoresis and used for RT-qPCR. Students calculated expressions of the two genes in dark treated leaves as percentages of those of the controls by using the 2(-ΔΔC) T method and the collected CT s. In the third week, class CT s, melting curves, students' calculations, and factors affecting the reliability of RT-qPCR results were summarized and discussed. Students' results show that (i) relatively pure and intact RNA samples are obtained; (ii) ACTIN2 is a better reference gene than the 18S rRNA; (iii) the dark treatment reduces both gene expressions to

The ability of students to understand the relationship between genotype and phenotype, and the mechanisms by which genotypes and phenotypes can change is essential for students studying genetics. To this end, we have developed a four-week laboratory called Blue Genes, which is designed to help novice students discriminate between two mechanisms by which the genetic material can be altered: genetic transformation and gene mutation. In the first week of the laboratory, students incubate a plasmid DNA with calcium chloride-treated Escherichia coli JM109 cells and observe a phenotype change from ampicillin sensitive to ampicillin resistant and from white color to blue color on plates containing 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) and isopropyl β-D-thiogalactopyranoside (IPTG). Over the course of the next three weeks, students use a battery of approaches including plasmid DNA isolation experiments, restriction maps, and PCR to differentiate between mutation and transformation. The students ultimately come to the conclusion that the changes in phenotypes are due to genetic transformation and not mutation based on the evidence generated over the four-week period. Pre-laboratory tests and post-laboratory tests indicate that this set of exercises is successful in helping students differentiate between transformation and mutation. The laboratory is designed for underclassmen and is a good prerequisite for an apprentice-based research opportunity, although it is not designed as a class based research experience. Potential modifications and future directions of the laboratory based upon student experiences and assessment are presented.

Objective To investigate the pregnancy complications, perinatal outcomes, and congenital abnormalities (CAs) that occurred in Beijing, China, when pregnant women became infected with the 2009 pandemic influenza A (H1N1) (H1N1pdm). Methods Pregnancy complications, perinatal outcomes, and CAs were compared among 3 groups of pregnant women. The 23 women in group 1 were confirmed to harbor viral RNA; the 23 in group 2 had serum levels of virus-specific antibodies against H1N1pdm, meaning that they were suspected of being infected with the virus; and the 93 in group 3 had no detectable virus-specific antibodies. Results Perinatal outcomes and pregnancy complications were not significantly different in groups 1 and 3. Higher percentages of stillbirths (12.0%) and placental disorders (13.0%) were observed in group 2 than in group 3. Many women in group 2 (62.5%) experienced symptoms of having a cold during pregnancy and most took no medication. Two cases of CA occurred in group 1, in the offspring of women infected in the second trimester. Conclusion When left untreated, infection with the 2009 H1N1pdm virus during pregnancy appears to have increased fetal mortality and morbidity. Because CAs are traumatic for all concerned, their possible association with the virus should be further evaluated.

Osteosarcoma, the most common primary bone tumor in young adults, is characterized by local invasion and distant metastasis. But detailed mechanisms of tumorigenicity and metastasis of osteosarcoma are not well known. We report the involvement of calpains, a family of calcium-activated, cysteine proteases, in the invasive and metastatic processes of human osteosarcoma cells. By using siRNA treatment, the expression of mu- and m-calpains were downregulated in human Saos-2 osteosarcoma cells. Both the adhesive and invasive potentials were significantly attenuated in calpain siRNA-transfected human Saos-2 osteosarcoma cells. MMPs are the main factors involved in malignant tumor invasion and metastasis. siRNA of calpains also significantly inhibited the secretion of MMP-2 in Saos-2 cells. These results suggest that mu- and m-calpains are important in the invasion and metastasis of human osteosarcoma cells, and calpains might be targeted to reduce tumor progression.

The effects of pretreatment and modified atmosphere packaging (MAP) on the quality of fresh-cut pineapples stored at 4°C were evaluated for 7 days. The pretreatment was conducted by immersing the pineapple slices in a solution containing 0.25% ascorbic acid and 10% sucrose for 2min. MAP contained 4% oxygen, 10% carbon dioxide and 86% nitrogen. Both the pretreatment and MAP could reduce the respiration rate, ethylene production, textural and colour deteriorations, as well as the overall sensory deterioration in fresh-cut pineapples. MAP could restrain the growth of microbes, but the pretreatment showed little effect. Fresh-cut pineapples exhibited wet surface and off-flavour after storage at 4°C for 3 days, while the pretreatment and MAP maintained the quality for up to 7 days. Copyright © 2007 John Wiley & Sons, Ltd.

9-Nitrocamptothecin (9-NC) is a newly developed poorly soluble derivative of camptothecin and has a wide spectrum of anticancer activity in preclinical evaluation. The effects of the dose and administration route on pharmacokinetics and lactone/carboxylate equilibrium of 9-NC were studied in rats. A single intravenous dose of 1.5, 3 or 6 mg/kg of 9-NC solution was given to male rats (n=6 per dose level). In another study, a single dose of 6 mg/kg 9-NC solution was given orally to rats (n=6). Plasma samples were drawn at predetermined intervals and the concentrations of lactone, carboxylate and total 9-NC were determined by a validated HPLC method. Pharmacokinetic analysis was performed using non-compartmental analysis. Analysis of variance showed that the pharmacokinetic characteristics of lactone, carboxylate and total 9-NC were all independent of dose (p>0.05). Based on the AUC measurements, the lactone 9-NC constituted 52%±4%, 49%±6% and 55%±6% of the circulating total 9-NC in rats after intravenous administration of 1.5, 3, 6 mg/kg 9-NC solution, respectively. After oral administration of 6 mg/kg, the pharmacokinetics parameters were significantly different from those of intravenous administration at the same dose (p

This study assessed the ability of history students to choose the essay topic on which they can get the highest score. A second, equally important question was whether the score on the chosen topic was more highly related to other indicators of proficiency in history than the score on the unchosen topic. Overall, for both U.S. and European history, scores were about one third of a standard deviation higher for the preferred topic than for the other topic. For U.S. history, about 32% of the students made the wrong choice; that is, 32% got a higher score on the other topic than on the preferred topic. In European history, 29% made the wrong choice. In the U.S. history sample, the preferred essay correlated .40 with an external criterion score, compared to .34 for the other essay; in the European history sample, the preferred essay correlated .52 with the external criterion, compared to .44 for the other topic. On a number of national examinations, examinees are asked to select one of several possible topics and write an essay on the topic that they have chosen. With different students writing on different topics (essentially taking different tests), it may be difficult or impossible to equate scores across topics (Wainer & Thissen, 1994). If knowledge of a specific narrow subject area or topic is being assessed, it makes little sense to allow choice.

Using factor analysis, we conducted an assessment of multidimensionality for 6 forms of the Law School Admission Test (LSAT) and found 2 subgroups of items or factors for each of the 6 forms. The main conclusion of the factor analysis component of this study was that the LSAT appears to measure 2 different reasoning abilities: inductive and deductive. The technique of N. J. Dorans & N. M. Kingston (1985) was used to examine the effect of dimensionality on equating. We began by calibrating (with item response theory [IRT] methods) all items on a form to obtain Set I of estimated IRT item parameters. Next, the test was divided into 2 homogeneous subgroups of items, each having been determined to represent a different ability (i.e., inductive or deductive reasoning). The items within these subgroups were then recalibrated separately to obtain item parameter estimates, and then combined into Set II. The estimated item parameters and true-score equating tables for Sets I and II corresponded closely.

GRE verbal and quantitative scores and undergraduate grade point average were evaluated as predictors of multiple measures of long-term graduate school success. The measures of success were cumulative graduate grade point average and faculty ratings on three student characteristics: mastery of the discipline, professional productivity, and communication skill. Seven graduate institutions and 21 graduate departments in biology, chemistry, education, English, and psychology collaborated in order to identify measures of valued outcomes, develop reports useful to individual departments and graduate schools, and initiate a database for future studies. Results are reported for all departments combined and by discipline and, where sample sizes permitted, for master's and doctoral degree students, men and women, U.S. citizens and noncitizens, domestic ethnic groups, and test takers who took the GRE computer-based test and those who took the paper-and-pencil version of the test. The results indicate that the combination of GRE scores and undergraduate grade point average strongly predicts cumulative graduate grade point average and faculty ratings. These results hold in each discipline and appear to hold in the small subgroups.