Impact of climate induced glacial melting on coastal marine systems in the Western Antarctic Peninsula region

IMCOAST is an international research program that features a multidisciplinary approach involving geo and biological sciences, field investigations, remote sensing and modeling and knowledge into the hydrographical and biological history of the marine coastal ecosystems of the Western Antarctic Peninsula region

Aspectos ecofisiológicos de dos forrajeras estivales de los pastizales de la Depresión del Salado (Paspalum dilatatum Poir. y Bothriochloa laguroides D. C.)

p.57-74Dos forrajeras nativas de los pastizales de la Depresión del Salado fueron sometidas a campo y en invernáculo a distintos tratamientos de defoliación y sombreado. Se analizó el efecto de los tratamientos sobre la aparición, floración y muerte de macollos, nivel de reservas y crecimiento radical. En las plantas del ensayo a campo se observó un aumento en el ritmo de macollaje como consecuencia de la defoliación. Los niveles de reservas y la aparición de raíces por planta no fueron afectados por los tratamientos. Diferente fue el resultado de las plantas tratadas en el invernáculo donde se observó un efecto detrimental de la defoliación sobre la aparición de macollos y biomasa radical. El ensayo a campo permitió tener una visión más integral de la respuesta de las plantas al medio analizándose diversas hipótesis

Human liver stem cell-derived microvesicles accelerate hepatic regeneration in hepatectomized rats

Several studies indicate that adult stem cells may improve the recovery from acute tissue injury. It has been suggested that they may contribute to tissue regeneration by the release of paracrine factors promoting proliferation of tissue resident cells. However, the factors involved remain unknown. In the present study we found that microvesicles (MVs) derived from human liver stem cells (HLSC) induced in vitro proliferation and apoptosis resistance of human and rat hepatocytes. These effects required internalization of MVs in the hepatocytes by an α4-integrin-dependent mechanism. However, MVs pre-treated with RNase, even if internalized, were unable to induce hepatocyte proliferation and apoptosis resistance, suggesting an RNA-dependent effect. Microarray analysis and quantitative RT-PCR demonstrated that MVs were shuttling a specific subset of cellular mRNA, such as mRNA associated in the control of transcription, translation, proliferation and apoptosis. When administered in vivo, MVs accelerated the morphological and functional recovery of liver in a model of 70% hepatectomy in rats. This effect was associated with increase in hepatocyte proliferation and was abolished by RNase pre-treatment of MVs. Using human AGO2, as a reporter gene present in MVs, we found the expression of human AGO2 mRNA and protein in the liver of hepatectomized rats treated with MVs. These data suggested a translation of the MV shuttled mRNA into hepatocytes of treated rats. In conclusion, these results suggest that MVs derived from HLSC may activate a proliferative program in remnant hepatocytes after hepatectomy by a horizontal transfer of specific mRNA subsets

Reaction of a polar gravel‐spit system to atmospheric warming and glacier retreat as reflected by morphology and internal sediment geometries (South Shetland Islands, Antarctica)

Sedimentary architecture and morphogenetic evolution of a polar bay-mouth gravel-spit system are revealed based on topographic mapping, sedimentological data, radiocarbon dating and ground-penetrating radar investigations. Data document variable rates of spit progradation in reaction to atmospheric warming synchronous to the termination of the last glacial re-advance (LGR, 0.45–0.25 ka BP), the southern hemisphere equivalent of the Little Ice Age cooling period. Results show an interruption of spit progradation that coincides with the proposed onset of accelerated isostatic rebound in reaction to glacier retreat. Spit growth resumed in the late 19th century after the rate of isostatic rebound decreased, and continues until today. The direction of modern spit progradation, however, is rotated northwards compared with the growth axis of the early post-LGR spit. This is interpreted to reflect the shift and strengthening in the regional wind field during the last century. A new concept for the interplay of polar gravel-spit progradation and glacio-isostatic adjustment is presented, allowing for the prediction of future coastal evolution in comparable polar settings

Microparticle-mediated transfer of the viral receptors CAR and CD46, and the CFTR channel in a CHO cell model confers new functions to target cells

Cell microparticles (MPs) released in the extracellular milieu can embark plasma membrane and intracellular components which are specific of their cellular origin, and transfer them to target cells. The MP-mediated, cell-to-cell transfer of three human membrane glycoproteins of different degrees of complexity was investigated in the present study, using a CHO cell model system. We first tested the delivery of CAR and CD46, two monospanins which act as adenovirus receptors, to target CHO cells. CHO cells lack CAR and CD46, high affinity receptors for human adenovirus serotype 5 (HAdV5), and serotype 35 (HAdV35), respectively. We found that MPs derived from CHO cells (MP-donor cells) constitutively expressing CAR (MP-CAR) or CD46 (MP-CD46) were able to transfer CAR and CD46 to target CHO cells, and conferred selective permissiveness to HAdV5 and HAdV35. In addition, target CHO cells incubated with MP-CD46 acquired the CD46-associated function in complement regulation. We also explored the MP-mediated delivery of a dodecaspanin membrane glycoprotein, the CFTR to target CHO cells. CFTR functions as a chloride channel in human cells and is implicated in the genetic disease cystic fibrosis. Target CHO cells incubated with MPs produced by CHO cells constitutively expressing GFP-tagged CFTR (MP-GFP-CFTR) were found to gain a new cellular function, the chloride channel activity associated to CFTR. Time-course analysis of the appearance of GFP-CFTR in target cells suggested that MPs could achieve the delivery of CFTR to target cells via two mechanisms: the transfer of mature, membrane-inserted CFTR glycoprotein, and the transfer of CFTR-encoding mRNA. These results confirmed that cell-derived MPs represent a new class of promising therapeutic vehicles for the delivery of bioactive macromolecules, proteins or mRNAs, the latter exerting the desired therapeutic effect in target cells via de novo synthesis of their encoded proteins

Microvesicles secreted from equine amniotic cells and their potential role in in vitro cell tendon repair

The regenerative mechanisms ascribed to mesenchymal stem cells (MSCs) are classified into 3 categories: differentiating into damaged cell types, supplying nutrients, and improving survival/functions of the endogenous cells via paracrine actions. However, because of the inhospitable microenvironment of the injured tissues, a proportion of the implanted MSCs may quickly die, suggesting that other mechanisms might be present. This notion is supported by the overlapping beneficial effect (in terms of time of healing) resulted after the injection of AMCs or of amniotic mesenchymal cells - conditioned medium (AMC-CM) in equine spontaneous injured tendons and ligaments. Microvesicles (MVs) released by cells are an integral component of the cell-to-cell communication network involved in tissue regeneration.In the present study, MVs secreted by AMCs were investigated with Nanosigth instrument and TEM. Then, the in vitro incorporation of MVs into equine tendon cells was studied by a dose-response curve. Lastly, the ability of MVs to counteract an in vitro inflammatory process induced by lipolysaccaride on tendon cells was studied evaluating the expression of pro-inflammatory genes like metallopeptidase (MPP) 1 and 13, and prostaglandin-endoperoxide synthase 2 (COX2). Results demonstrated that AMCs secreted MVs ranging in size from 100 to 1000 nm with a prevalence of 100-200 nm large MVs. Tendon cells were able to uptake them with an inverse relationship between concentration and time. The greatest incorporation was detectable at 40x106 MVs/ml after 72h. MVs induced down-regulation of MMP1 and MMP13, suggesting that they may have contributed, along with soluble factors, to in vivo tendon regeneration

Association of CD40 Gene Polymorphisms with Sporadic Breast Cancer in Chinese Han Women of Northeast China

BACKGROUND: Breast cancer is a polygenetic disorder with a complex inheritance pattern. Single nucleotide polymorphisms (SNPs), the most common genetic variations, influence not only phenotypic traits, but also interindividual predisposition to disease, treatment outcomes with drugs and disease prognosis. The co-stimulatory molecule CD40 plays a prominent role in immune regulation and homeostasis. Accumulating evidence suggests that CD40 contributes to the pathogenesis of cancer. Here, we set out to test the association between polymorphisms in the CD40 gene and breast carcinogenesis and tumor pathology. METHODOLOGY AND PRINCIPAL FINDINGS: Four SNPs (rs1800686, rs1883832, rs4810485 and rs3765459) were genotyped by the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method in a case-control study including 591 breast cancer patients and 600 age-matched healthy controls. Differences in the genotypic distribution between breast cancer patients and healthy controls were analyzed by the Chi-square test for trends. Our preliminary data showed a statistically significant association between the four CD40 gene SNPs and sporadic breast cancer risk (additive P = 0.0223, 0.0012, 0.0013 and 0.0279, respectively). A strong association was also found using the dominant, recessive and homozygote comparison genetic models. In the clinical features analysis, significant associations were observed between CD40 SNPs and lymph node metastasis, human epidermal growth factor receptor 2 (C-erbB2), estrogen receptor (ER), progesterone receptor (PR) and tumor protein 53 (P53) statuses. In addition, our haplotype analysis indicated that the haplotype C(rs1883832)G(rs4810485), which was located within the only linkage disequilibrium (LD) block identified, was a protective haplotype for breast cancer, whereas T(rs1883832)T(rs4810485) increased the risk in the studied population, even after correcting the P value for multiple testing (P = 0.0337 and 0.0430, respectively). CONCLUSIONS AND SIGNIFICANCE: Our findings primarily show that CD40 gene polymorphisms contribute to sporadic breast cancer risk and have a significant association with clinicopathological features among Chinese Han women from the Heilongjiang Province