Chromosome movement in lysed mitotic cells is inhibited by vanadate.

Mitotic PtK1 cells, lysed at anaphase into a carbowax 20 M Brij 58 solution, continue to move chromosomes toward the spindle poles and to move the spindle poles apart at 50% in vivo rates for 10 min. Chromosome movements can be blocked by adding metabolic inhibitors to the lysis medium and inhibition of movement can be reversed by adding ATP to the medium. Vanadate at micromolar levels reversibly inhibits dynein ATPase activity and movement of demembranated flagella and cilia. It does not affect glycerinated myofibril contraction or myosin ATPase activty at less than millimolar concentrations. Vanadate at 10--100 micron reversibly inhibits anaphase movement of chromosomes and spindle elongation. After lysis in vanadate, spindles lose their fusiform appearance and become more barrel shaped. In vitro microtubule polymerization is insensitive to vanadate

College Enhancement Strategies and Socioeconomic Inequality

The study provides new information on the relationships between students’ socioeconomic backgrounds, utilization of college enhancement strategies, and subsequent 4-year college enrollment. Enhancement strategies represent student behaviors used to bolster the competitiveness of a college application, such as Advanced Placement exams and a variety of extracurricular activities. By drawing on two national datasets that span the 1990s (NELS) and the 2000s (ELS), the study uncovers how these relationships have changed during a period marked by escalating demand for college and growing class inequality. The findings provide partial evidence of class adaptation (Alon in Am Soc Rev 74:731–755, 2009) based on the combination of increased use of multiple enhancement strategies (“high overall use”) among higher SES students and increased influence of high overall enhancement strategy use in predicting college enrollment, particularly selective college enrollment. Implications are discussed in terms of the higher education system and pervasive social inequality

Masked mRNA is stored with aggregated nuclear speckles and its asymmetric redistribution requires a homolog of mago nashi

<p>Abstract</p> <p>Background</p> <p>Many rapidly developing systems rely on the regulated translation of stored transcripts for the formation of new proteins essential for morphogenesis. The microspores of the water fern <it>Marsilea vestita </it>dehydrate as they mature. During this process both mRNA and proteins required for subsequent development are stored within the microspores as they become fully desiccated and enter into senescence. At this point microspores become transcriptionally silent and remain so upon rehydration and for the remainder of spermatogenesis. Transcriptional silencing coupled with the translation of preformed RNA makes the microspore of <it>M. vestita </it>a useful system in which to study post-transcriptional regulation of RNA.</p> <p>Results</p> <p>We have characterized the distribution of mRNA as well as several conserved markers of subnuclear bodies within the nuclei of desiccating spores. During this period, nuclear speckles containing RNA were seen to aggregate forming a single large coalescence. We found that aggregated speckles contain several masked mRNA species known to be essential for spermatogenesis. During spermatogenesis masked mRNA and associated speckle proteins were shown to fragment and asymmetrically localize to spermatogenous but not sterile cells. This asymmetric localization was disrupted by RNAi knockdown of the <it>Marsilea </it>homolog of the Exon Junction Complex core component Mago nashi.</p> <p>Conclusions</p> <p>A subset of masked mRNA is stored in association with nuclear speckles during the dormant phase of microspore development in <it>M. vestita</it>. The asymmetric distribution of specific mRNAs to spermatogenous but not sterile cells mirrors their translational activities and appears to require the EJC or EJC components. This suggests a novel role for nuclear speckles in the post-transcriptional regulation of transcripts.</p

Kinetics of Humoral and Memory B Cell Response Induced by the Plasmodium Falciparum 19-kilodalton Merozoite Surface Protein 1 in mice.

The 19-kDa carboxyl-terminal fragment of the merozoite surface protein-1 (MSP-1(19)) has been shown to regulate antibody (Ab)-mediated protective immunity to blood-stage malaria infection. But the serological memory to this antigen tends to be short-lived, and little is known of the mechanisms that regulate the formation of B cell memory to MSP-1(19) antigen. We studied the formation of B cell memory response after immunization with the recombinant 19-kDa Plasmodium falciparum merozoite surface protein 1 (PfMSP-1(19)). Immunization with PfMSP-1(19) resulted in delayed increase in germinal center (GC) B cell numbers. This poor GC reaction correlated with short-lived PfMSP-1(19)-specific antibodies in serum and the short life of PfMSP-1(19)-specific plasma cells and memory B cells (MBCs) in spleen and bone marrow. PfMSP-1(19)-specific MBCs were capable of producing antigen (Ag)-specific Ab-secreting cell (ASC) responses that were short-lived following challenge immunization of the immune mice with antigen or transgenic Plasmodium berghei parasite expressing PfMSP-1(19) in place of native P. berghei MSP-1(19) at 8 weeks after the last immunization or following adoptive transfer into naive hosts. However, no protection was achieved in PfMSP-1(19) immune mice or recipient mice with PfMSP-1(19)-specific MBCs following challenge with transgenic P. berghei. Our findings suggest that PfMSP-1(19)-specific IgG production by short-lived plasma cells combined with the poor ability of the PfMSP-1(19)-induced MBCs to maintain the anamnestic IgG responses failed to contribute to protection against infection

Changes of selected qualitative distinguishing features during storage of restored juices from concentrates

Celem pracy było określenie zmian zawartości polifenoli ogółem, w tym antocyjanów oraz aktywności przeciwutleniającej odtwarzanych z koncentratów soków truskawkowych i z czarnych porzeczek bez dodatków oraz wzbogacanych preparatem pektyn wysoko metylowanych, przechowywanych w temp. 20°C bez dostępu światła. W trakcie 4-miesięcznego przechowywania stwierdzono ubytek zawartości antocyjanów i polifenoli ogółem, co powodowało obniżenie się pojemności przeciwutleniającej. Zawartość antocyjanów badano metodą HPLC. Pomiar zdolności wygaszania wolnych rodników wykonano metodą EPR przy użyciu stabilnego rodnika DPPH (1,1-difenylo-2-pikrylohydrazylu). Stwierdzono, że dodatek pektyn znacznie spowalnia obniżanie aktywności przeciwutleniającej. Bezpośrednio po wytworzeniu pojemność przeciwutleniająca próbek soków z czarnych porzeczek z dodatkiem pektyny, jaki i kontrolnych była zbliżona i wynosiła odpowiednio 3,48 i 3,41 mM Troloxu/100 ml. Jednak po 4 miesiącach wartości te wynosiły już 3,29 oraz 3,01 mM Troloxu/100 ml, co świadczy o stabilizującym wpływie dodatku pektyn.The objective of this study was the assessment of total polyphenolic content and antioxidant activity in strawberry and blackcurrant juices with addition of pectins in comparison to clear juices. Samples were storage at 20°C without light. During 4 months storage the decrease in anthocyanins and polyphenols content was observed in both juices as well as radical scavenging activity was lower than for control samples. The composition of these juices were determined by HPLC and radical scavenging properties were measured by EPR using stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. After preparation of blackcurrant juices antioxidant activity values were similar to samples with addition of pectins and control. antioxidant activity was 3,48 and 3,41 mM Troloxu/100 ml respectively. After 4 months antioxidant activity were 3,29 and 3,01 mM Troloxu/100 ml respectively. It was shown that anthocyanins are stabilizing by pectin addition