In the recent report,
Vision and Change in Undergraduate Biology Education: A Call to Action,
the American Association for the Advancement of Science laid out a blueprint for reforming undergraduate ...biology education. A key component of the vision is ensuring that all students understand certain core concepts that are necessary for biological literacy, and that they are able to demonstrate a set of core competencies in disciplinary practice.
The core concepts and competencies were integrated into every aspect of a first year Inquiries in Biology course at Northeastern University. This course is offered to students majoring in Biology, Biochemistry, and Behavioral Neuroscience who have Advanced Placement credit for General Biology. The class is small (35 students), and is organized largely in a seminar format with no textbook and very minimal lecturing. However, the integration strategies presented here should be applicable to larger classes, as well as classes that are more lecture-focused.
We studied bushy-tailed woodrats (Neotoma cinerea occidentalis) in the eastern Washington Cascade Range to estimate their density and survival in 3 typical dry forest cover types. We predicted ...woodrat density to be high, moderate, and low in mature mixed-conifer forests, young mixed-conifer forests, and open ponderosa pine forests, respectively. We livetrapped on 8 × 8 grids (280 m) over an 8-day period each autumn for 4 years to obtain Huggins mark–recapture estimates of woodrat density. We captured woodrats 617 times and marked 193 individual woodrats in 12 sample stands during 42,165 trap nights. The sex ratio of captures was 62% female and 38% male. Adults made up 79% of captures. Woodrat density averaged 0.49 animals/ha among all cover types and years; woodrat density did not differ among types. Regardless of cover type, stands fell into 4 woodrat-density groups, with densities ranging from 0.13 to 0.93 woodrats/ha. Classification tree analysis revealed that woodrat-density groups could be predicted well (proportional reduction in error = 0.73 to 0.89) by the type and amount of cover provided by large snags, mistletoe brooms, and soft downed logs. Over the 4-year period, woodrat density ranged from 0.28 animals/ha to 0.87 animals/ha, increasing each year at a rate of λ = 1.8 consistently among cover types. A moderate (r = 0.55) density-dependent response in per capita rate of increase was detected. The apparent annual survival rate was a low 0.14. Management to reduce woody fuels and to restore low-intensity high-frequency fire regimes in ponderosa pine and dry Douglas-fir forest likely will reduce bushy-tailed woodrat populations unless prescriptions can mitigate the loss of snag, mistletoe, and downed log cover.
The objective of this study was to investigate seasonal variation in the C, N and S stable isotope composition of retail organic and conventional Irish beef. A total of 242 beef samples (127 organic, ...115 conventional) was collected in a one-year survey and analysed by isotope ratio mass spectrometry. The δ
13C time series in conventional beef was significantly non-random, with a pronounced seasonal positive shift of >2‰ between December and June, whilst δ
13C in organic beef was less variable and significantly more negative. In conventional beef, δ
15N was remarkably invariant (remaining close to 7‰) throughout the year, while organic beef was more variable and also significantly lower in δ
15N. The S isotope composition (δ
34S) exhibited a complex seasonal pattern in both types of beef. These results show that seasonal patterns can occur in the isotopic composition of beef, probably reflecting seasonality in animal feeding practices modulated by tissue turnover rates. Such seasonal variation needs to be considered in the isotopic authentication of beef and other animal-derived products.
Aggressive angiomyxoma (AAM) is a distinctive neoplasm seen in the female genital tract. We present the clinicopathological findings of 12 female patients with AAM. Immunohistochemical analysis for ...vimentin, desmin, smooth-muscle actin (SMA), muscle-specific actin (MSA), S-100, CD44, estrogen receptor (ER), and progesterone receptor (PR) was performed. Mean patient age was 39 years (range 20-77 years). Eight tumors arose in the vulva, two in the suburethral area, and two in the perirectal area. Three were pedunculated (two vulvar and one suburethral). Perineal tumors were locally excised, with limited removal of adjacent tissue or tissue surrounding the pedicle base of pedunculated tumors. Perirectal tumors were removed by wide excision. Tumors ranged 2.8-40.0 cm in size. Eleven patients were followed-up (mean 19 months). Recurrence occurred in one patient 48 months after tumor resection from perirectum and abdomen. Immunohistochemistry showed tumor positivity for vimentin (11/11), desmin (8/11), CD44 (8/11), ER (10/12), PR (11/12), and SMA (3/11). MSA and S-100 were negative. In summary, AAM in the perineum especially pedunculated tumors may possibly require only local excision for definitive treatment. Furthermore, the majority of AAM have CD44 expression.
The vitamin K-dependent γ-glutamyl carboxylase catalyzes the posttranslational conversion of glutamic acid to γ-carboxyglutamic acid, an amino acid critical to the function of the vitamin K-dependent ...blood coagulation proteins. Given the functional similarity of mammalian vitamin K-dependent carboxylases and the vitamin K-dependent carboxylase fromConus textile, a marine invertebrate, we hypothesized that structurally conserved regions would identify sequences critical to this common functionality. Furthermore, we examined the diversity of animal species that maintain vitamin K-dependent carboxylation to generate γ-carboxyglutamic acid. We have cloned carboxylase homologs in full-length or partial form from the beluga whale (Delphinapterus leucas), toadfish (Opsanus tau), chicken (Gallus gallus), hagfish (Myxine glutinosa), horseshoe crab (Limulus polyphemus), and cone snail (Conus textile) to compare these structures to the known bovine, human, rat, and mouse cDNA sequences. Comparison of the predicted amino acid sequences identified a nearly perfectly conserved 38-amino acid residue region in all of these putative carboxylases. In addition, this amino acid motif is also present in theDrosophila genome and identified a Drosophilahomolog of the γ-carboxylase. Assay of hagfish liver demonstrated vitamin K-dependent carboxylase activity in this hemichordate. These results demonstrate the broad distribution of the vitamin K-dependent carboxylase gene, including a highly conserved motif that is likely critical for enzyme function. The vitamin K-dependent biosynthesis of γ-carboxyglutamic acid appears to be a highly conserved function in the animal kingdom.
The Energetic Particle Detector Rodríguez-Pacheco, J.; Wimmer-Schweingruber, R. F.; Mason, G. M. ...
Astronomy and astrophysics (Berlin),
10/2020, Letnik:
642
Journal Article
Recenzirano
Odprti dostop
After decades of observations of solar energetic particles from space-based observatories, relevant questions on particle injection, transport, and acceleration remain open. To address these ...scientific topics, accurate measurements of the particle properties in the inner heliosphere are needed. In this paper we describe the Energetic Particle Detector (EPD), an instrument suite that is part of the scientific payload aboard the Solar Orbiter mission. Solar Orbiter will approach the Sun as close as 0.28 au and will provide extra-ecliptic measurements beyond ∼30° heliographic latitude during the later stages of the mission. The EPD will measure electrons, protons, and heavy ions with high temporal resolution over a wide energy range, from suprathermal energies up to several hundreds of megaelectronvolts/nucleons. For this purpose, EPD is composed of four units: the SupraThermal Electrons and Protons (STEP), the Electron Proton Telescope (EPT), the Suprathermal Ion Spectrograph (SIS), and the High-Energy Telescope (HET) plus the Instrument Control Unit that serves as power and data interface with the spacecraft. The low-energy population of electrons and ions will be covered by STEP and EPT, while the high-energy range will be measured by HET. Elemental and isotopic ion composition measurements will be performed by SIS and HET, allowing full particle identification from a few kiloelectronvolts up to several hundreds of megaelectronvolts/nucleons. Angular information will be provided by the separate look directions from different sensor heads, on the ecliptic plane along the Parker spiral magnetic field both forward and backwards, and out of the ecliptic plane observing both northern and southern hemispheres. The unparalleled observations of EPD will provide key insights into long-open and crucial questions about the processes that govern energetic particles in the inner heliosphere.
The proteasome is a multi-protein complex that degrades cellular proteins as well as foreign proteins destined for antigen presentation. The latter function involves the immunoproteasome, in which ...several proteasome subunits are exchanged for γ-interferon-induced subunits. The transporter associated with antigen processing (TAP) transports proteasome-generated peptides across the membrane of the endoplasmic reticulum (ER) prior to presentation on the plasma membrane. We demonstrate interactions between the cytoplasmic domains of TAP subunits and subunits of both the proteasome and the immunoproteasome, suggesting direct targeting of antigenic peptides to the ER via a TAP–proteasome association. We also show interaction between one of the cytoplasmic domains of P-glycoprotein and a proteasome subunit, but not the corresponding immunoproteasome subunit, suggesting a possible role for P-glycoprotein in the transport of proteasome-derived peptides.
The cell-cycle checkpoint protein p53 both directs terminal differentiation and protects embryos from DNA damage. To study invertebrate p53 during early development, we identified three ...differentially expressed p53 family members (p53, p97, p120) in the surf clam, Spisula solidissima. In these mollusks, p53 and p97 occur in both embryonic and adult tissue, whereas p120 is exclusively embryonic. We sequenced, cloned, and characterized p120 cDNA. The predicted protein, p120, resembles p53 across all evolutionarily conserved regions and contains a C-terminal extension with a sterile alpha motif (SAM) as in p63 and p73. These vertebrate forms of p53 are required for normal inflammatory, epithelial, and neuronal development. Unlike clam p53 and p97, p120 mRNA and protein levels are temporally expressed in embryos, with mRNA levels decreasing with increasing p120 protein (R2=0.97). Highest surf clam p120 mRNA levels coincide with the onset of neuronal growth. In earlier work we have shown that neuronal development is altered by exposure to polychlorinated biphenyls (PCBs), a neurotoxic environmental contaminant. In this study we show that PCBs differentially affect expression of the three surf clam p53 family members. p120 mRNA and protein are reduced the most and earliest in development, p97 protein shows a smaller and later reduction, and p53 protein levels do not change. For the first time we report that unlike p53 and p97, p120 is specifically embryonic and expressed in a time-dependent manner. Furthermore, p120 responds to PCBs by 48 hr when PCB-induced suppression of the serotonergic nervous system occurs.
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