Reoxidation of cytosolic NADPH in Kluyveromyces lactis

Saccharomyces cerevisiae and Kluyveromyces lactis are considered to be the prototypes of two distinct metabolic models of facultatively-aerobic yeasts: Crabtree-positive/fermentative and Crabtree-negative/respiratory, respectively. Our group had previously proposed that one of the molecular keys supporting this difference lies in the mechanisms involved in the reoxidation of the NADPH produced as a consequence of the activity of the pentose phosphate pathway. It has been demonstrated that a significant part of this reoxidation is carried out in K. lactis by mitochondrial external alternative dehydrogenases which use NADPH, the enzymes of S. cerevisiae being NADH-specific. Moreover, the NADPH-dependent pathways of response to oxidative stress appear as a feasible alternative that might co-exist with direct mitochondrial reoxidation.     

Radiotherapy for cervical cancer: Chilean consensus of the Society of Radiation Oncology

BackgroundCervical cancer is a public health problem in Latin America. Radiotherapy plays a fundamental role both as definitive or adjuvant treatment. There are important intra and inter-country differences regarding access and availability of radiotherapy facilities in this region. The aim of a study was to standardize the basic clinical and technical criteria for the radiation treatment of patients with CC in Chile and provide a guide for Latin American Radiation Oncologists.Materials and methodsForty-one expert radiation oncologists from the Chilean Radiation Oncology Society made a consensus using the Delphi methodology.ResultsThere was a high degree of agreement for each of the recommendations. Those with the lowest percentage were related to the definition of the conformal 3D technique as the standard for definitive external radiotherapy (81%) and the criteria for extended nodal irradiation (85%).ConclusionsThese recommendations present an updated guide for radiotherapy treatment of patients with cervical cancer for Latin America. Those should be implemented according to local resources of each institution.     

Breaking Caenorhabditis elegans the easy way using the Balch homogenizer: an old tool for a new application

The biochemical quantification of sterols in insects has been difficult because only small amounts of tissues can be obtained from insect bodies and because sterol metabolites are structurally related. We have developed a highly specific and sensitive quantitative method for determining of the concentrations of seven sterols—7-dehydrocholesterol, desmosterol, cholesterol, ergosterol, campesterol, stigmasterol, and β-sitosterol—using a high performance liquid chromatography–atmospheric pressure chemical ionization–tandem mass spectrometry (HPLC/APCI-MS/MS). The sterols were extracted from silkworm larval tissues using the Bligh and Dyer method and were analyzed using HPLC/APCI-MS/MS with selected reaction monitoring, using cholesterol-3,4-¹³C₂ as an internal standard. The detection limits of the method were between 12.1 and 259 fmol. The major sterol in most silkworm larval tissues was cholesterol, whereas only small quantities of the dietary sterols were detected. Thus, a simple, sensitive, and specific method was successfully developed for the quantification of the sterol concentrations in each tissue of an individual silkworm larva. This method will be a useful tool for investigating to molecular basis of sterol physiology in insects, facilitating the quantification of femtomole quantities of sterols in biological samples.     

Human Wharton’s Jelly Mesenchymal Stem Cells Plasticity Augments Scar-Free Skin Wound Healing with Hair Growth

Human mesenchymal stem cells (MSCs) are a promising candidate for cell-based transplantation and regenerative medicine therapies. Thus in the present study Wharton’s Jelly Mesenchymal Stem Cells (WJ-MSCs) have been derived from extra embryonic umbilical cord matrix following removal of both arteries and vein. Also, to overcome the clinical limitations posed by fetal bovine serum (FBS) supplementation because of xenogeneic origin of FBS, usual FBS cell culture supplement has been replaced with human platelet lysate (HPL). Apart from general characteristic features of bone marrow-derived MSCs, wharton jelly-derived MSCs have the ability to maintain phenotypic attributes, cell growth kinetics, cell cycle pattern, in vitro multilineage differentiation plasticity, apoptotic pattern, normal karyotype-like intrinsic mesenchymal stem cell properties in long-term in vitro cultures. Moreover, the WJ-MSCs exhibited the in vitro multilineage differentiation capacity by giving rise to differentiated cells of not only mesodermal lineage but also to the cells of ectodermal and endodermal lineage. Also, WJ-MSC did not present any aberrant cell state upon in vivo transplantation in SCID mice and in vitro soft agar assays. The immunomodulatory potential assessed by gene expression levels of immunomodulatory factors upon exposure to inflammatory cytokines in the fetal WJ-MSCs was relatively higher compared to adult bone marrow-derived MSCs. WJ-MSCs seeded on decellularized amniotic membrane scaffold transplantation on the skin injury of SCID mice model demonstrates that combination of WJ-MSCs and decellularized amniotic membrane scaffold exhibited significantly better wound-healing capabilities, having reduced scar formation with hair growth and improved biomechanical properties of regenerated skin compared to WJ-MSCs alone. Further, our experimental data indicate that indocyanin green (ICG) at optimal concentration can be resourcefully used for labeling of stem cells and in vivo tracking by near infrared fluorescence non-invasive live cell imaging of labelled transplanted cells, thus proving its utility for therapeutic applications.     

Range-expanding populations of a globally introduced weed experience negative plant-soil feedbacks

Background

Biological invasions are fundamentally biogeographic processes that occur over large spatial scales. Interactions with soil microbes can have strong impacts on plant invasions, but how these interactions vary among areas where introduced species are highly invasive vs. naturalized is still unknown. In this study, we examined biogeographic variation in plant-soil microbe interactions of a globally invasive weed, Centaurea solstitialis (yellow starthistle). We addressed the following questions (1) Is Centaurea released from natural enemy pressure from soil microbes in introduced regions? and (2) Is variation in plant-soil feedbacks associated with variation in Centaurea''s invasive success?

Methodology/Principal Findings

We conducted greenhouse experiments using soils and seeds collected from native Eurasian populations and introduced populations spanning North and South America where Centaurea is highly invasive and noninvasive. Soil microbes had pervasive negative effects in all regions, although the magnitude of their effect varied among regions. These patterns were not unequivocally congruent with the enemy release hypothesis. Surprisingly, we also found that Centaurea generated strong negative feedbacks in regions where it is the most invasive, while it generated neutral plant-soil feedbacks where it is noninvasive.

Conclusions/Significance

Recent studies have found reduced below-ground enemy attack and more positive plant-soil feedbacks in range-expanding plant populations, but we found increased negative effects of soil microbes in range-expanding Centaurea populations. While such negative feedbacks may limit the long-term persistence of invasive plants, such feedbacks may also contribute to the success of invasions, either by having disproportionately negative impacts on competing species, or by yielding relatively better growth in uncolonized areas that would encourage lateral spread. Enemy release from soil-borne pathogens is not sufficient to explain the success of this weed in such different regions. The biogeographic variation in soil-microbe effects indicates that different mechanisms may operate on this species in different regions, thus establishing geographic mosaics of species interactions that contribute to variation in invasion success.     

Glucose inhibits the shoot bud formation in the moss <Emphasis Type="Italic">Bryum billarderi</Emphasis>

Plant development is controlled by certain factors such as nutrient availability, environmental cues and the presence of signalling molecules. It has been proposed that phytohormones interact with sugars to modulate important processes in vascular plants. Cytokinins are key hormones because they regulate a large number of metabolic events, and sugars act as regulatory signals at several points in the life cycle. Bryum bilarderi Schwägr is a moss that was isolated by our group in the central highlands of Mexico and has demonstrated the ability to tolerate abiotic stresses. To study the effect of cytokinins and their interaction with glucose in bud induction, different concentrations of cytokinins with glucose were tested. One micromolar N-6-benzylaminopurine provided the best results for bud induction, but when 100 mM glucose was added, bud formation was inhibited. This glucose concentration also favoured the spread of the protonemal colony. These data demonstrate that N-6-benzylaminopurine is more effective than kinetin in inducing buds, and that glucose plays an important role as an inhibitory signalling molecule for the bud induction process that is mediated by cytokinins in the moss B. billarderi.