Effect of N and P Fertilization on Weed Flora of Maize (Zea Mays L.) Crop

From May to September 2016, a corn hybrid was sown in a field in central Greece. The experiment was laid out in a randomized complete block design with six replications and five fertilization treatments, namely NutriSphere-N Nitrogen Fertilizer (75%), NutriSphere-N Nitrogen Fertilizer (100%), AVAIL Phosphorus Fertilizer (75%), AVAIL Phosphorus Fertilizer (100%) and unfertilized (control). Data analysis confirmed that the different type of fertilization has a significant effect on the composition of weed flora. In particular, the results of the present study indicated significant differences between the fertilization treatments concerning density and diversity of weeds. Furthermore, weed diversity in the control treatment was highest, while it was lower in plots receiving application of N and P. However, total weed dry mass was lower in plots receiving no fertilizer and P fertilization, and highest in plots receiving N. Differences in terms of weed growth between the two types of fertilization could be attributed to differences revealed in the composition of the weed flora.

Effect of Different Types of Fertilization on Vigna unguiculata subsp. sesquipedalis Crop

A field experiment was conducted at Pylos, Greece to compare the effect of different types of fertilization on yardlong bean (Vigna unguiculata subsp. sesquipedalis) crop. The conventional treatment plots were fertilized with an inorganic fertilizer, whereas the organic treatments plots received organic compost. Data analysis confirmed no significant correlation between plant height and type of fertilization, but there was significant correlation between length of pods and type of fertilization. In particular, morphological characteristics of yardlong bean were enhanced by inorganic fertilization in comparison with the organic fertilization.  Organic farming increased significantly the number on root nodules in comparison with conventional farming

Comparative analysis of pSMA198 found in Streptococcus macedonicus ACA-DC 198, the first streptococcal plasmid of the pCI305/pWV02 family of theta-replicating replicons

Here we analyze pSMA198, the first plasmid isolated from Streptococcus macedonicus ACA-DC 198, and we attempt to clarify the route of its original acquisition. Based on the similarity profiles of the plasmid’s replication initiation protein (Rep) and its origin of replication (ori), pSMA198 was found to be a novel member of the pCI305/pWV02 family of theta-replicating plasmids. The pCI305/pWV02 family consists of plasmids of narrow host range that are mainly found in lactococcal species. Comparative analysis of the pSMA198 revealed a high degree of similarity with plasmids pSK11b, pVF22 and pIL5 over its replication backbone, its mobilization backbone and most of its length, respectively. All these three plasmids have been isolated from Lactococcus lactis strains deriving from milk or its products supporting that S. macedonicus acquired pSMA198 from the latter species and that this acquisition took place in the dairy environment. Both pSMA198 and the chromosome of S. macedonicus exhibit a high degree of pseudogenes, indicating that they must have evolved under the same gene decay processes. Furthermore, we were able to determine chromosomal regions that may have originated from pSMA198, also supporting a long co-existence of the two replicons. In addition, pSMA198 is carried by S. macedonicus strains segregated in five different genotypes by pulsed-field gel electrophoresis (PFGE), showing that pSMA198’s acquisition is not a recent event. We propose that our overall analysis of pSMA198 points towards the habituation of S. macedonicus ACA-DC 198 to the dairy environment

Identification of a Protein Mediating Respiratory Supercomplex Stability

SummaryThe complexes of the electron transport chain associate into large macromolecular assemblies, which are believed to facilitate efficient electron flow. We have identified a conserved mitochondrial protein, named respiratory supercomplex factor 1 (Rcf1—Yml030w), that is required for the normal assembly of respiratory supercomplexes. We demonstrate that Rcf1 stably and independently associates with both Complex III and Complex IV of the electron transport chain. Deletion of the RCF1 gene caused impaired respiration, probably as a result of destabilization of respiratory supercomplexes. Consistent with the hypothetical function of these respiratory assemblies, loss of RCF1 caused elevated mitochondrial oxidative stress and damage. Finally, we show that knockdown of HIG2A, a mammalian homolog of RCF1, causes impaired supercomplex formation. We suggest that Rcf1 is a member of an evolutionarily conserved protein family that acts to promote respiratory supercomplex assembly and activity

Oxygen Consumption Can Regulate the Growth of Tumors, a New Perspective on the Warburg Effect

The unique metabolism of tumors was described many years ago by Otto Warburg, who identified tumor cells with increased glycolysis and decreased mitochondrial activity. However, "aerobic glycolysis" generates fewer ATP per glucose molecule than mitochondrial oxidative phosphorylation, so in terms of energy production, it is unclear how increasing a less efficient process provides tumors with a growth advantage.We carried out a screen for loss of genetic elements in pancreatic tumor cells that accelerated their growth as tumors, and identified mitochondrial ribosomal protein L28 (MRPL28). Knockdown of MRPL28 in these cells decreased mitochondrial activity, and increased glycolysis, but paradoxically, decreased cellular growth in vitro. Following Warburg's observations, this mutation causes decreased mitochondrial function, compensatory increase in glycolysis and accelerated growth in vivo. Likewise, knockdown of either mitochondrial ribosomal protein L12 (MRPL12) or cytochrome oxidase had a similar effect. Conversely, expression of the mitochondrial uncoupling protein 1 (UCP1) increased oxygen consumption and decreased tumor growth. Finally, treatment of tumor bearing animals with dichloroacetate (DCA) increased pyruvate consumption in the mitochondria, increased total oxygen consumption, increased tumor hypoxia and slowed tumor growth.We interpret these findings to show that non-oncogenic genetic changes that alter mitochondrial metabolism can regulate tumor growth through modulation of the consumption of oxygen, which appears to be a rate limiting substrate for tumor proliferation

How the histological structure of some lung cancers shaped almost 70 years of radiobiology

Pivotal research led by Louis Harold Gray in the 1950s suggested that oxygen plays a vital role during radiotherapy. By proving that tumours have large necrotic cores due to hypoxia and that hypoxic cells require significantly larger doses of ionising radiation to achieve the same cell kill, Thomlinson and Gray inspired the subsequent decades of research into better defining the mechanistic role of molecular oxygen at the time of radiation. Ultimately, the work pioneered by Thomlinson and Gray led to numerous elegant studies which demonstrated that tumour hypoxia predicts for poor patient outcomes. Furthermore, this subsequently resulted in investigations into markers and measurement of hypoxia, as well as modification strategies. However, despite an abundance of pre-clinical data supporting hypoxia-targeted treatments, there is limited widespread application of hypoxia-targeted therapies routinely used in clinical practice. Significant contributing factors underpinning disappointing clinical trial results include the use of model systems which are more hypoxic than human tumours and a failure to stratify patients based on levels of hypoxia. However, translating the original findings of Thomlinson and Gray remains a research priority with the potential to significantly improve patient outcomes and specifically those receiving radiotherapy

Microenvironmental control of glucose metabolism in tumors by regulation of pyruvate dehydrogenase

During malignant progression cancer cells undergo a series of changes, which promote their survival, invasiveness and metastatic process. One of them is a change in glucose metabolism. Unlike normal cells, which mostly rely on the tricarboxylic acid cycle (TCA), many cancer types rely on glycolysis. Pyruvate dehydrogenase complex (PDC) is the gatekeeper enzyme between these two pathways and is responsible for converting pyruvate to acetyl-CoA, which can then be processed further in the TCA cycle. Its activity is regulated by PDP (pyruvate dehydrogenase phosphatases) and PDHK (pyruvate dehydrogenase kinases). Pyruvate dehydrogenase kinase exists in 4 tissue specific isoforms (PDHK1-4), the activities of which are regulated by different factors, including hormones, hypoxia and nutrients. PDHK1 and PDHK3 are active in the hypoxic tumor microenvironment and inhibit PDC, resulting in a decrease of mitochondrial function and activation of the glycolytic pathway. High PDHK1/3 expression is associated with worse prognosis in patients, which makes them a promising target for cancer therapy. However, a better understanding of PDC's enzymatic regulation in vivo and of the mechanisms of PDHK-mediated malignant progression is necessary for the design of better PDHK inhibitors and the selection of patients most likely to benefit from such inhibitors.status: Published onlin

Tumor Hypoxia Blocks Wnt Processing and Secretion through the Induction of Endoplasmic Reticulum Stress▿

Poorly formed tumor blood vessels lead to regions of microenvironmental stress due to depletion of oxygen and glucose and accumulation of waste products (acidosis). These conditions contribute to tumor progression and correlate with poor patient prognosis. Here we show that the microenvironmental stresses found in the solid tumor are able to inhibit the canonical Wnt/β-catenin signaling pathway. However, tumor cells harboring common β-catenin pathway mutations, such as loss of adenomatous polyposis coli, are insensitive to this novel hypoxic effect. The underlying mechanism responsible is hypoxia-induced endoplasmic reticulum (ER) stress that inhibits normal Wnt protein processing and secretion. ER stress causes dissociation between GRP78/BiP and Wnt, an interaction essential for its correct posttranslational processing. Microenvironmental stress can therefore block autocrine and paracrine signaling of the Wnt/β-catenin pathway and negatively affect tumor growth. This study provides a general paradigm relating oxygen status to ER function and growth factor signaling

Impact of a Single-Tube PCR Assay for the Detection of Haemophilus influenzae Serotypes a, c, d, e and f on the Epidemiological Surveillance in Greece

Background: The decrease in the rate of meningitis due to Haemophilus influenzae type b after vaccine introduction and a possible change in epidemiology of H. influenzae disease highlights the need for continuous serotype surveillance. Methods: A single-tube multiplex PCR assay for serotyping of H. influenzae was developed and deployed. Results: During 2003–2020, 108 meningitis cases due to H. influenzae were notified; 86 (80%) were confirmed and serotyped by molecular methods. The overall specificity and sensitivity of the assay were estimated (100% PPV and NPV respectively). The overall mean annual reported incidence for H. influenzae was 0.02, while for Hib and non-b meningitis equaled 0.02 and 0.03 per 100 000, respectively. Analysis by age group revealed that H. influenzae peaks in toddlers and children 0–4 years and in adults >45 years old. Among the serotyped cases, 39.8% were identified as Hib, 46.3% as NTHi, and 0.9% and 2.8% as serotypes a (Hia) and f (Hif)) respectively. Conclusions: Low incidence due to Hib was observed while non-typeable H. influenzae (NTHi) and serotypes Hia and Hif seem to emerge. The application of the current assay discloses the ongoing change of invasive H. influenzae disease trends during the Hib post-vaccine era

First report of meningococcal ciprofloxacin resistance in Greece due to invasive isolates of the sequence type ST-3129

International audienceA local outbreak caused by Neisseria meningitidis occurred in the migration camp in the Greek island of Lesbos during January-February 2020 (4 of 5 cases). In total, 5 samples positive for N. meningitidis were further investigated for sero-/genogroup, PorA, and WGS analysis. MenB was found among 3 cases, while in two cases, MenY was identified. WGS analysis and antibiotic susceptibility testing on the 2 culture positive MenB samples showed the new ST-3129, ciprofloxacin-resistant clone was circulating among the immigrants in the aforementioned camp. This is the first report of ciprofloxacin resistance in Greece