Contest behavior in territorial male butterflies: does size matter?

Although intrasexual contests generally favor bigger or stronger individuals, the relevance of body size to war of attrition-typedisputes between weaponless animals such as butterflies isunclear. In this study I aimed to investigate the significanceof size in this context by studying territorial contests inHypolimnas bolina (L.), a species that exhibits consistentseasonal plasticity in body size. In this species adult ageis positively correlated with large size in spring but withsmall size in autumn. This shift allowed independent evaluationof the relevance of each variable (size and age) to intrasexualcontest success. Observation of a population of marked individualsindicated that only age appeared important, with the winnersof pair-wise contests significantly older than losers in both seasons, and with contests lasting longer when the age differencebetween the combatants was small. Age was also linked to residency;residents won 99% of all contests. This study suggests thatsize does not matter in these aerial disputes, but age andresidency do. It is not yet possible to determine whether olderbutterflies are intrinsically better competitors, or whether they simply have greater opportunity to find a vacant territory.     

TREX1 degrades the 3′ end of the small DNA oligonucleotide products of nucleotide excision repair in human cells

The nucleotide excision repair (NER) machinery removes UV photoproducts from DNA in the form of small, excised damage-containing DNA oligonucleotides (sedDNAs) ∼30 nt in length. How cells process and degrade these byproducts of DNA repair is not known. Using a small scale RNA interference screen in UV-irradiated human cells, we identified TREX1 as a major regulator of sedDNA abundance. Knockdown of TREX1 increased the level of sedDNAs containing the two major UV photoproducts and their association with the NER proteins TFIIH and RPA. Overexpression of wild-type but not nuclease-inactive TREX1 significantly diminished sedDNA levels, and studies with purified recombinant TREX1 showed that the enzyme efficiently degrades DNA located 3′ of the UV photoproduct in the sedDNA. Knockdown or overexpression of TREX1 did not impact the overall rate of UV photoproduct removal from genomic DNA or cell survival, which indicates that TREX1 function in sedDNA degradation does not impact NER efficiency. Taken together, these results indicate a previously unknown role for TREX1 in promoting the degradation of the sedDNA products of the repair reaction. Because TREX1 mutations and inefficient DNA degradation impact inflammatory and immune signaling pathways, the regulation of sedDNA degradation by TREX1 may contribute to photosensitive skin disorders.     

The Role of Kv1.2 Channel in Electrotaxis Cell Migration

Voltage‐gated potassium Kv1.2 channels play pivotal role in maintaining of resting membrane potential and, consequently, regulation of cellular excitability of neurons. Endogenously generated electric field (EF) have been proven as an important regulator for cell migration and tissue repair. The mechanisms of ion channel involvement in EF‐induced cell responses are extensively studied but largely are poorly understood. In this study we generated three COS‐7 clones with different expression levels of Kv1.2 channel, and confirmed their functional variations with patch clamp analysis. Time‐lapse imaging analysis showed that EF‐induced cell migration response was Kv1.2 channel expression level depended. Inhibition of Kv1.2 channels with charybdotoxin (ChTX) constrained the sensitivity of COS‐7 cells to EF stimulation more than their motility. Immunocytochemistry and pull‐down analyses demonstrated association of Kv1.2 channels with actin‐binding protein cortactin and its re‐localization to the cathode‐facing membrane at EF stimulation, which confirms the mechanism of EF‐induced directional migration. This study displays that Kv1.2 channels represent an important physiological link in EF‐induced cell migration. The described mechanism suggests a potential application of EF which may improve therapeutic performance in curing injuries of neuronal and/or cardiac tissue repair, post operational therapy, and various degenerative syndromes. J. Cell. Physiol. 231: 1375–1384, 2016. © 2015 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.     

Ly-1 inducer and Ly-1,2 acceptor t cells in the feedback suppression circuit bear an I-J-subregion controlled determinant

An I-J-subregion controlled determinant is expressed on Ly-1 inducer and Ly-1,2 acceptor T cells in the feedback suppression circuit. Ly-1 T cells absorb the I-J antibody reactive with the Ly-1,2 acceptor T cell, suggesting that both inducer and acceptor T cells have the same 1-J determinant. Since less than 10 percent of Ly-1 or Ly-1,2 T cells are killed by anti-I-J plus complement treatment, the I-J determinant demarcates functionally distinct subsets of both the Ly-1 and Ly-1,2 T-cell sets. This I-J determinant is not expressed on a detectable number of Ly-1 helper T cells which induce B lymphocytes to produce anti-sheep red cell antibody in tissue culture.Abbreviations used in this paper NMS normal mouse serum - BSS balanced salt solution - PFC plaque forming cells - Ig immunoglobulin - SRBC sheep red blood cells     

The 1994 experimental opening of the Bonnet Carre Spillway to divert Mississippi River water into Lake Pontchartrain, Louisiana

A diversion of Mississippi River water into Lake Pontchartrain, Louisiana, USA by way of the Bonnet Carre Spillway has been proposed as a restoration technique to help offset regional wetland loss. An experimental diversion of Mississippi River water into Lake Pontchartrain was carried out in April 1994 to monitor the fate of nutrients and sediments in the spillway and Lake Pontchartrain. Approximately 6.4×10⁸ m³ of Mississippi River water was diverted into Lake Pontchartrain over 42 days. As water passed through the Bonnet Carre Spillway, there were reductions in total suspended sediment concentrations of 82–83%, nitrite+nitrate (NO_x) of 28–42%, in total nitrogen (TN) of 26–30%, and in total phosphorus (TP) of 50–59%. 3.9±1.1 cm of accretion was measured in the spillway. Nutrient concentrations at the freshwater plume edge in Lake Pontchartrain compared to the Mississippi River were lower for NO_x (44–81%), TN (37–57%), and TP (40–70%), and generally higher for organic nitrogen (−7–57%). The Si:N ratio generally increased and the N:P ratio decreased from the river to the plume edge. Nutrient stoichiometric ratios indicate water at the plume edge was not silicate limited, suggesting conditions favoring diatomic phytoplankton.     

Integrated pipeline for mass spectrometry-based discovery and confirmation of biomarkers demonstrated in a mouse model of breast cancer

Despite their potential to impact diagnosis and treatment of cancer, few protein biomarkers are in clinical use. Biomarker discovery is plagued with difficulties ranging from technological (inability to globally interrogate proteomes) to biological (genetic and environmental differences among patients and their tumors). We urgently need paradigms for biomarker discovery. To minimize biological variation and facilitate testing of proteomic approaches, we employed a mouse model of breast cancer. Specifically, we performed LC-MS/MS of tumor and normal mammary tissue from a conditional HER2/Neu-driven mouse model of breast cancer, identifying 6758 peptides representing >700 proteins. We developed a novel statistical approach (SASPECT) for prioritizing proteins differentially represented in LC-MS/MS datasets and identified proteins over- or under-represented in tumors. Using a combination of antibody-based approaches and multiple reaction monitoring-mass spectrometry (MRM-MS), we confirmed the overproduction of multiple proteins at the tissue level, identified fibulin-2 as a plasma biomarker, and extensively characterized osteopontin as a plasma biomarker capable of early disease detection in the mouse. Our results show that a staged pipeline employing shotgun-based comparative proteomics for biomarker discovery and multiple reaction monitoring for confirmation of biomarker candidates is capable of finding novel tissue and plasma biomarkers in a mouse model of breast cancer. Furthermore, the approach can be extended to find biomarkers relevant to human disease.     

入侵种喜旱莲子草和莲子草的营养生长和光合作用对温度的响应

比较温度对入侵种喜旱莲子草(Alternantheraphiloxeroides(Mart.)Griseb.)和其本土近缘种莲子草(A.sessilis(L.)DC.)的营养生长、叶片光合作用及叶绿素荧光的影响。实验将生长均衡的这两种植物放在不同温度(10℃、15℃、20℃、25℃、30℃)的光照培养箱中处理28d。结果表明,喜旱莲子草营养生长的速率和对温度的响应明显不同于莲子草:前者主茎生长的有效积温明显低于后者,分别是11.6d℃和27.0d℃;而新叶萌发的有效积温高于后者,分别是12.1d℃和6.7d℃。入侵种主茎和叶的发育起点温度都比本土种低,分别是10.4℃、11.0℃和12.8℃、14.9℃,表明喜旱莲子草的发育对低温反应不及莲子草敏感。对两种植物叶片的光合作用和叶绿素荧光的测定结果还表明:入侵种比本土种有较高的最大净光合速率和光饱和点,尤其在25℃时;10-30℃的温度范围内喜旱莲子草的最大光化学效率Fv/Fm没有显著变化,而莲子草在10℃低温条件下Fv/Fm值显著降低。较快的主茎生长速率、较宽的温度适应范围以及较高的光合能力可能使喜旱莲子草比本地种具有更强的竞争力,从而在其入侵过程中起了重要作用。     

Babesia bovis: molecular and biological characteristics of cloned parasite lines

An in vivo limiting dilution technique was used to produce several Babesia bovis cloned lines with which to study the basis of virulence and immunogenicity in this parasite. DNA hybridization using a cloned DNA fragment from the BabR locus demonstrated that the cloned lines were a more restricted genetic population than the parent strain. Biosynthetic labeling and immunoprecipitation studies indicated that the cloned lines differed from each other and from the parentals in the expression of a small number of polypeptides and antigens. Animal trials with three of the lines demonstrated that the parental line contains both virulent and avirulent parasite populations, at least three of which are not tick transmissible, and that while the lines do provide significant protection against heterologous challenge, they may not give as effective protection as the parental line. These experiments demonstrated the existence of subpopulations with distinctive molecular and biological properties, providing evidence that the attenuation process is based on the selection of preexisting parasite subpopulations combined with the ability of these parasites to vary genetically.     

Integral membrane protein located in the apical complex of Plasmodium falciparum.

We describe the cloning of a novel antigen of Plasmodium falciparum which contains a hydrophobic domain typical of an integral membrane protein. This antigen is designated apical membrane antigen 1 because it appears to be located in the apical complex. Apical membrane antigen 1 appears to be transported to the merozoite surface near the time of schizont rupture.