Bacteria associated with wood tissues of Esca-diseased grapevines: functional diversity and synergy with Fomitiporia mediterranea to degrade wood components

Fungi are considered to cause grapevine trunk diseases such as esca that result in wood degradation. For instance, the basidiomycete Fomitiporia mediterranea (Fmed) is overabundant in white rot, a key type of wood-necrosis associated with esca. However, many bacteria colonize the grapevine wood too, including the white rot. In this study, we hypothesized that bacteria colonizing grapevine wood interact, possibly synergistically, with Fmed and enhance the fungal ability to degrade wood. We isolated 237 bacterial strains from esca-affected grapevine wood. Most of them belonged to the families Xanthomonadaceae and Pseudomonadaceae. Some bacterial strains that degrade grapevine-wood components such as cellulose and hemicellulose did not inhibit Fmed growth in vitro. We proved that the fungal ability to degrade wood can be strongly influenced by bacteria inhabiting the wood. This was shown with a cellulolytic and xylanolytic strain of the Paenibacillus genus, which displays synergistic interaction with Fmed by enhancing the degradation of wood structures. Genome analysis of this Paenibacillus strain revealed several gene clusters such as those involved in the expression of carbohydrate-active enzymes, xylose utilization and vitamin metabolism. In addition, certain other genetic characteristics of the strain allow it to thrive as an endophyte in grapevine and influence the wood degradation by Fmed. This suggests that there might exist a synergistic interaction between the fungus Fmed and the bacterial strain mentioned above, enhancing grapevine wood degradation. Further step would be to point out its occurrence in mature grapevines to promote esca disease development.     

The Influences of Chromium Supplementation on Metabolic Status in Patients with Type 2 Diabetes Mellitus and Coronary Heart Disease

Biological Trace Element Research - This investigation was conducted to determine the effects of chromium supplementation on metabolic status in diabetic patients with coronary heart disease (CHD)....     

Human Epidermal Growth Factor Receptor 2 (HER2) Impedes MLK3 Kinase Activity to Support Breast Cancer Cell Survival

Human epidermal growth factor receptor 2 (HER2) is amplified in ∼15–20% of human breast cancer and is important for tumor etiology and therapeutic options of breast cancer. Up-regulation of HER2 oncogene initiates cascades of events cumulating to the stimulation of transforming PI3K/AKT signaling, which also plays a dominant role in supporting cell survival and efficacy of HER2-directed therapies. Although investigating the underlying mechanisms by which HER2 promotes cell survival, we noticed a profound reduction in the kinase activity of a pro-apoptotic mixed lineage kinase 3 (MLK3) in HER2-positive (HER2+) but not in HER2-negative (HER2−) breast cancer tissues, whereas both HER2+ and HER2− tumors expressed a comparable level of MLK3 protein. Furthermore, the kinase activity of MLK3 was inversely correlated with HER2+ tumor grades. Moreover, HER2-directed drugs such as trastuzumab and lapatinib as well as depletion of HER2 or HER3 stimulated MLK3 kinase activity in HER2+ breast cancer cell lines. In addition, the noted inhibitory effect of HER2 on MLK3 kinase activity was mediated via its phosphorylation on Ser⁶⁷⁴ by AKT and that pharmacological inhibitors of PI3K/AKT prevented trastuzumab- and lapatinib-induced stimulation of MLK3 activity. Consistent with the pro-apoptotic function of MLK3, stable knockdown of MLK3 in the HER2+ cell line blunted the pro-apoptotic effects of trastuzumab and lapatinib. These findings suggest that HER2 activation inhibits the pro-apoptotic function of MLK3, which plays a mechanistic role in mediating anti-tumor activities of HER2-directed therapies. In brief, MLK3 represents a newly recognized integral component of HER2 biology in HER2+ breast tumors.     

Adaptive genetic variation mediates bottom-up and top-down control in an aquatic ecosystem

Research in eco-evolutionary dynamics and community genetics has demonstrated that variation within a species can have strong impacts on associated communities and ecosystem processes. Yet, these studies have centred around individual focal species and at single trophic levels, ignoring the role of phenotypic variation in multiple taxa within an ecosystem. Given the ubiquitous nature of local adaptation, and thus intraspecific variation, we sought to understand how combinations of intraspecific variation in multiple species within an ecosystem impacts its ecology. Using two species that co-occur and demonstrate adaptation to their natal environments, black cottonwood (Populus trichocarpa) and three-spined stickleback (Gasterosteus aculeatus), we investigated the effects of intraspecific phenotypic variation on both top-down and bottom-up forces using a large-scale aquatic mesocosm experiment. Black cottonwood genotypes exhibit genetic variation in their productivity and consequently their leaf litter subsidies to the aquatic system, which mediates the strength of top-down effects from stickleback on prey abundances. Abundances of four common invertebrate prey species and available phosphorous, the most critically limiting nutrient in freshwater systems, are dictated by the interaction between genetic variation in cottonwood productivity and stickleback morphology. These interactive effects fit with ecological theory on the relationship between productivity and top-down control and are comparable in strength to the effects of predator addition. Our results illustrate that intraspecific variation, which can evolve rapidly, is an under-appreciated driver of community structure and ecosystem function, demonstrating that a multi-trophic perspective is essential to understanding the role of evolution in structuring ecological patterns.     

Exposure to an organometal compound stimulates adipokine and cytokine expression in white adipose tissue

ObjectiveWhite adipose tissue (WAT) is now considered a defined tissue capable of interactions with other organ systems. WAT role in elevating the level of systemic chronic inflammation suggests that alterations in this tissue as the result of disease or environmental factors may influence the development and progression of various obesity-related pathologies. This study investigated WAT cell-specific responses to an organometal compound, trimethyltin (TMT), to determine possible contribution to induced inflammation.MethodsHuman primary mature adipocytes and macrophage differentiated THP-1 cells were cultured in TMT presence and relative toxicities and different adipokine levels were determined. The inflammatory response was examined in TMT presence for primary cells from obese ob/ob mice WAT, and after TMT injection in ob/ob mice.ResultsBoth adipocytes and macrophages were resistant to cell death induced by TMT. However, adipocytes cultured in TMT presence showed increased expression of TNFα and IL-6, and modified leptin levels. In macrophage cultures, TMT also increased TNFα and IL-6, while MCP-1 and MIP-1α were decreased. In vivo, a single injection of TMT in ob/ob mice, elevated TNFα, MIP-1α and adiponectin in WAT.ConclusionsElevation of the inflammatory related products can be induced by chemical exposure in adipocytes and macrophages, as well as murine WAT. These data suggest that numerous factors, including a systemic chemical exposure, can induce an inflammatory response from the WAT. Furthermore, when characterizing both chemical-induced toxicity and the progression of the chronic inflammation associated with elevated WAT content, such responses in this target tissue should be taken into consideration.     

Expression,purification and functional characterization of recombinant Zucchini yellow mosaic virus HC-Pro

HC-Pro is a helper component-proteinase which acts as a multifunctional protein in the potyviral life cycle. Apart from its proteolytic activity, HC-Pro has the capacity to bind duplex small RNAs (sRNAs). To investigate HC-Pro-mediated sRNA binding in vitro, high amounts of purified protein are required. For this purpose, the Zucchini yellow mosaic virus (ZYMV) HC-Pro was expressed as a fusion with hexa-histidine (6xHis) or maltose-binding protein (MBP) in Escherichia coli. The expressed fusion proteins were purified by affinity chromatography. 6xHis:HC-Pro and MBP:HC-Pro were partially soluble. Electrophoretic mobility-shift assays demonstrated that only MBP:HC-Pro exhibits the sRNA binding activity. The recombinant HC-Pro bound 21 bp siRNAs as well as 19 bp and 24 bp siRNAs. A point mutation in the highly conserved FRNK box produced the HC-Pro^FINK protein, previously shown to be associated with reduced viral symptoms and weak sRNA binding. In this study, sRNA binding of the MBP:HA-HC-Pro^FINK was not detectable. The high yield of purified HC-Pro offers the possibility to study the biochemistry of the protein in detail.     

Larval survival,host plant preferences and developmental responses of the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) on wild brassicaceous species

The diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) is an important pest of cultivated brassicaceous crops worldwide. The host plant preferences, developmental biology and survival and longevity of P. xylostella are relatively well understood on commercial crop species; however, its relationship with brassicaceous weeds is poorly known. Sinapis arvensis L., Erysimum cheiranthoides L. and Capsella bursa‐pastoris (L.) Medicus are among the most common brassicaceous weeds worldwide and can serve as important bridge hosts of P. xylostella. In this study, preference and performance of P. xylostella were compared on these weed species. In free‐choice situations, females deposited 5.5 and 18.8 times more eggs on S. arvensis than on E. cheiranthoides and C. bursa‐pastoris, respectively. Survival from neonate to pupa and from pupa to adult was highest on S. arvensis and E. cheiranthoides and lowest on C. bursa‐pastoris. Development was fastest, foliage consumption was greatest, pupae and silk cocoons were heaviest, adult body masses and longevities were highest and forewings were largest for both females and males when reared as larvae on S. arvensis. Realized fecundity of new generation adults was highest for individuals reared on S. arvensis compared to those reared on E. cheiranthoides or C. bursa‐pastoris. Relative growth rates of pupae and adults were highest on S. arvensis, suggesting that this plant species is a high‐quality host for P. xylostella compared with other species tested. Potential impacts of these wild brassicaceous species on P. xylostella populations are discussed.     

Protection from obesity and diabetes by blockade of TGF-β/Smad3 signaling

Imbalances in glucose and energy homeostasis are at the core of the worldwide epidemic of obesity and diabetes. Here, we illustrate an important role of the TGF-β/Smad3 signaling pathway in regulating glucose and energy homeostasis. Smad3-deficient mice are protected from diet-induced obesity and diabetes. Interestingly, the metabolic protection is accompanied by Smad3(-)(/-) white adipose tissue acquiring the bioenergetic and gene expression profile of brown fat/skeletal muscle. Smad3(-/-) adipocytes demonstrate a marked increase in mitochondrial biogenesis, with a corresponding increase in basal respiration, and Smad3 acts as a repressor of PGC-1α expression. We observe significant correlation between TGF-β1 levels and adiposity in rodents and humans. Further, systemic blockade of TGF-β signaling protects mice from obesity, diabetes, and hepatic steatosis. Together, these results demonstrate that TGF-β signaling regulates glucose tolerance and energy homeostasis and suggest that modulation of TGF-β activity might be an effective treatment strategy for obesity and diabetes.     

Genetic diversity within and among the wild populations of Murraya koenigii (L.) Spreng., as revealed by ISSR analysis

Murraya koenigii (L.) Spreng., commonly known as curry leaf plant, is found in the different hilly regions of India. In the present study, fifty-nine accessions representing eight wild populations of M. koenigii were analyzed using thirteen ISSR primers. A total of 152 bands were amplified, out of which, 136 were polymorphic corresponding to 89.47% polymorphism across the accessions. The pairwise population genetic distances were calculated for all the populations that varied from 0.05 to 0.13 between the populations of M. koenigii. AMOVA and Nei’s genetic diversity analysis revealed higher genetic variations within populations than among the populations. The clustering of populations in the dendrogram was not in congruence with geographical affiliations. The results indicate that the ISSR method is sufficiently informative and powerful to estimate the genetic diversity in M. koenigii populations. As M. koenigii is an important wild plant genetic resource, therefore, information on genetic variability might be a potential source as breeding material for development of commercially valuable traits in M. koenigii plants.