Nuclear Envelope Protein Lem2 is Required for Mouse Development and Regulates MAP and AKT Kinases

The nuclear lamina, along with associated nuclear membrane proteins, is a nexus for regulating signaling in the nucleus. Numerous human diseases arise from mutations in lamina proteins, and experimental models for these disorders have revealed aberrant regulation of various signaling pathways. Previously, we reported that the inner nuclear membrane protein Lem2, which is expressed at high levels in muscle, promotes the differentiation of cultured myoblasts by attenuating ERK signaling. Here, we have analyzed mice harboring a disrupted allele for the Lem2 gene (Lemd2). No gross phenotypic defects were seen in heterozygotes, although muscle regeneration induced by cardiotoxin was delayed. By contrast, homozygous Lemd2 knockout mice died by E11.5. Although many normal morphogenetic hallmarks were observed in E10.5 knockout embryos, most tissues were substantially reduced in size. This was accompanied by activation of multiple MAP kinases (ERK1/2, JNK, p38) and AKT. Knockdown of Lem2 expression in C2C12 myoblasts also led to activation of MAP kinases and AKT. These findings indicate that Lemd2 plays an essential role in mouse embryonic development and that it is involved in regulating several signaling pathways. Since increased MAP kinase and AKT/mTORC signaling is found in other animal models for diseases linked to nuclear lamina proteins, LEMD2 should be considered to be another candidate gene for human disease.     

Platelet Recruitment Promotes Keratocyte Repopulation following Corneal Epithelial Abrasion in the Mouse

Corneal abrasion not only damages the epithelium but also induces stromal keratocyte death at the site of injury. While a coordinated cascade of inflammatory cell recruitment facilitates epithelial restoration, it is unclear if this cascade is necessary for keratocyte recovery. Since platelet and neutrophil (PMN) recruitment after corneal abrasion is beneficial to epithelial wound healing, we wanted to determine if these cells play a role in regulating keratocyte repopulation after epithelial abrasion. A 2 mm diameter central epithelial region was removed from the corneas of C57BL/6 wildtype (WT), P-selectin deficient (P-sel^-/-), and CD18 hypomorphic (CD18^hypo) mice using the Algerbrush II. Corneas were studied at 6h intervals out to 48h post-injury to evaluate platelet and PMN cell numbers; additional corneas were studied at 1, 4, 14, and 28 days post injury to evaluate keratocyte numbers. In WT mice, epithelial abrasion induced a loss of anterior central keratocytes and keratocyte recovery was rapid and incomplete, reaching ~70% of uninjured baseline values by 4 days post-injury but no further improvement at 28 days post-injury. Consistent with a beneficial role for platelets and PMNs in wound healing, keratocyte recovery was significantly depressed at 4 days post-injury (~30% of uninjured baseline) in P-sel^-/- mice, which are known to have impaired platelet and PMN recruitment after corneal abrasion. Passive transfer of platelets from WT, but not P-sel^-/-, into P-sel^-/- mice prior to injury restored anterior central keratocyte numbers at 4 days post-injury to P-sel^-/- uninjured baseline levels. While PMN infiltration in injured CD18^hypo mice was similar to injured WT mice, platelet recruitment was markedly decreased and anterior central keratocyte recovery was significantly reduced (~50% of baseline) at 4–28 days post-injury. Collectively, the data suggest platelets and platelet P-selectin are critical for efficient keratocyte recovery after corneal epithelial abrasion.     

Prominent Vessel Sign on Susceptibility-Weighted Imaging in Acute Stroke: Prediction of Infarct Growth and Clinical Outcome

Background and Purpose

Predicting the risk of further infarct growth in stroke patients is critical to therapeutic decision making. We aimed to predict early infarct growth and clinical outcome from prominent vessel sign (PVS) identified on the first susceptibility-weighted image (SWI) after acute stroke.

Materials and Methods

Twenty-two patients with middle cerebral artery (MCA) infarction had diffusion-weighted imaging, SWI, MR angiography, and clinical evaluation using the National Institutes of Health Stroke Scale at 7–60 hours and 5–14 days after stroke onset. Late-stage clinical evaluation at 1 and 3 months used the modified Rankin Scale. The infarct area and growth were scored from 10 (none) to 0 (infarct or growth in all 10 zones) using the Alberta Stroke Program Early CT Score (ASPECTS) system.

Results

Infarct growth on the second MRI occurred in 13 of 15 patients with PVS on the first MRI and not in any patient without PVS (n=7; r=0.86, P<0.001). The extent of PVS was significantly correlated with infarct growth (r=0.82, P<0.001) and early-stage outcome (P=0.02). No between-group difference in late-stage clinical outcome was found.

Conclusion

PVS on the first SWI after acute MCA territory stroke is a useful predictor of early infarct growth. Extensive PVS within the large MCA territory is related to poor early-stage outcome and could be useful for clinical assessment of stroke.     

Prevalence and Patterns of Tobacco Use in Bangladesh from 2009 to 2012: Evidence from International Tobacco Control (ITC) Study

Background

Smoking and passive smoking are collectively the biggest preventable cause of death in Bangladesh, with major public health burden of morbidity, disability, mortality and community costs. The available studies of tobacco use in Bangladesh, however, do not necessarily employ nationally representative samples needed to monitor the problem at a national scale. This paper examines the prevalence and patterns of tobacco use among adults in Bangladesh and the changes over time using large nationally representative comparable surveys.

Methods

Using data from two enumerations of the International Tobacco Control (ITC) Bangladesh Project conducted in 2009 and 2012, prevalence estimates are obtained for all tobacco products by socio-economic determinants and sample types of over 90,000 individuals drawn from over 30,000 households. Household level sample weights are used to obtain nationally representative prevalence estimates and standard errors. Statistical tests of difference in the estimates between two time periods are based on a logistic regression model that accounts for the complex sampling design. Using a multinomial logit model, the time trend in tobacco use status is identified to capture the effects of macro level determinants including changes in tobacco control policies.

Results

Between 2009 and 2012, overall tobacco use went down from 42.4% to 36.3%. The decline is more pronounced with respect to smokeless tobacco use than smoking. The prevalence of exclusive cigarette smoking went up from 7.2% to 10.6%; exclusive bidi smoking remained stable at around 2%; while smoking both cigarette and bidi went down from 4.6% to 1.8%; exclusive smokeless tobacco use went down from 20.2% to 16.9%; and both smokeless tobacco use and smoking went down from 8.4% to 5.1%. In general, the prevalence of tobacco use is higher among men, increases from younger to older age groups, and is higher among poorer people. Smoking prevalence is the highest among the slum population, followed by the tribal population, the national population and the border area population, suggesting greater burden of tobacco use among the disadvantaged groups.

Conclusions

The overall decline in tobacco use can be viewed as a structural shift in the tobacco market in Bangladesh from low value products such as bidi and smokeless tobacco to high value cigarettes, which is expected with the growth in income and purchasing power of the general population. Despite the reduction in overall tobacco use, the male smoking prevalence in Bangladesh is still high at 37%. The world average of daily smoking among men is 31.1%. The Tobacco Control Act 2005 and the Amendment have yet to make a significant impact in curbing tobacco usage in Bangladesh. The findings in this paper further suggest that the tobacco control policies in Bangladesh need to include targeted interventions to restrain the use of particular types of tobacco products among specific demographic and socio-economic groups of the population, such as smoked tobacco among men, smokeless tobacco among women, and both smoked and smokeless tobacco among those living in rural areas, those in low socio-economic status and those belonging to the tribal and the slum population.     

Trichoderma songyi sp. nov., a new species associated with the pine mushroom (Tricholoma matsutake)

A new species, Trichoderma songyi, was found to be associated with the pine mushroom (Tricholoma matsutake) in Korea. This species was isolated from three different substrates: Tricholoma matsutake basidiomata, as well as roots of Pinus densiflora and soil in the fairy ring. Based on its molecular and phenotypic characteristics, we demonstrate that Trichoderma songyi is unique and distinguishable from closely related species. We performed phylogenetic analyses based on two molecular markers, the genes for both translation elongation factor 1-alpha and the second largest subunit of RNA polymerase II. Phylogenetic analyses showed that Trichoderma songyi is closely related to Trichoderma koningii aggregate and Trichoderma caerulescens. Morphologically, Trichoderma songyi can be distinguished from these closely related taxa by its growth rates, colony morphology on PDA in darkness, and coconut-like odour. Due to the economic importance of the pine mushroom, the relationship between Trichoderma songyi and Tricholoma matsutake should be studied further.     

Fission yeast Pcp1 links polo kinase‐mediated mitotic entry to γ‐tubulin‐dependent spindle formation

The centrosomal pericentrin‐related proteins play pivotal roles in various aspects of cell division; however their underlying mechanisms remain largely elusive. Here we show that fission‐yeast pericentrin‐like Pcp1 regulates multiple functions of the spindle pole body (SPB) through recruiting two critical factors, the γ‐tubulin complex (γ‐TuC) and polo kinase (Plo1). We isolated two pcp1 mutants (pcp1‐15 and pcp1‐18) that display similar abnormal spindles, but with remarkably different molecular defects. Both mutants exhibit defective monopolar spindle microtubules that emanate from the mother SPB. However, while pcp1‐15 fails to localise the γ‐TuC to the mitotic SPB, pcp1‐18 is specifically defective in recruiting Plo1. Consistently Pcp1 forms a complex with both γ‐TuC and Plo1 in the cell. pcp1‐18 is further defective in the mitotic‐specific reorganisation of the nuclear envelope (NE), leading to impairment of SPB insertion into the NE. Moreover pcp1‐18, but not pcp1‐15, is rescued by overproducing nuclear pore components or advancing mitotic onset. The central role for Pcp1 in orchestrating these processes provides mechanistic insight into how the centrosome regulates multiple cellular pathways.     

Dihydro-pyrano[2,3-b]pyridines and tetrahydro-1,8-naphthyridines as CB1 receptor inverse agonists: Synthesis,SAR and biological evaluation

Synthesis and structure–activity relationships of cannabinoid-1 receptor (CB1R) inverse agonists based on dihydro-pyrano[2,3-b] pyridine and tetrahydro-1,8-naphtyridine scaffolds are presented. Rat food intake and pharmacokinetic evaluation of 13g, 13i, 13k and 17a revealed these compounds to be highly efficacious orally active modulators of CB1R.     

Spatial refuges and associational defenses promote harmful blooms of the alga Caulerpa sertularioides onto coral reefs

Extreme population fluctuations, or outbreaks, are driven by interacting processes that are often more complex than isolated changes in consumer or resource control. Blooms of the macroalga Caulerpa sertularioides in the eastern tropical Pacific overgrew and killed reef-building corals, with blooms onto reefs corresponding to cool La Niña phases of inter-decadal fluctuations of the El Niño–Southern Oscillation. We quantified factors responsible for the maintenance of C. sertularioides patches in off-reef areas, namely an associational mutualism with an epiphytic cyanobacteria (Lyngbya majuscula), coupled with spatial refuges at the scales of individual thalli and habitat. Maintenance of near reef algal populations with a strong response to nutrient addition showed that these populations were primed to bloom onto reefs in response to enhanced nutrient delivery, such as those potentially associated with La Niña conditions. However, our experiments demonstrated that no single factor related to consumer or resource control was likely to stimulate bloom formation in isolation. Rather, we propose a novel model of reef bloom formation where off-reef blooms are sustained by processes reducing consumer control, and then bloom onto reefs through an interaction between increased allochthonous nutrient input and an uncoupling of consumer control by an association with epiphytic cyanobacteria.     

GRAVITROPISM IN ABSCISIC-ACID DEFICIENT SEEDLINGS OF ZEA MAYS

We did not detect any abscisic acid (ABA) in roots or leaves of carotenoid-deficient mutants of Zea mays. Similarly, we did not detect any ABA in roots or leaves of seedlings treated with Fluridone (an inhibitor of carotenogenesis) even after subjecting them to polyethylene glycol (PEG)-induced moisture stress. Primary roots of untreated, Fluridone-treated, and mutant seedlings were strongly graviresponsive. These results suggest that 1) ABA is not necessary for positive gravitropism by primary roots of these cultivars of Z. mays, and 2) ABA is synthesized via the carotenoid pathway.