Plasmids of Psychrotolerant Polaromonas spp. Isolated From Arctic and Antarctic Glaciers – Diversity and Role in Adaptation to Polar Environments

Cold-active bacteria of the genus Polaromonas (class Betaproteobacteria) are important components of glacial microbiomes. In this study, extrachromosomal replicons of 26 psychrotolerant Polaromonas strains, isolated from Arctic and Antarctic glaciers, were identified, sequenced, and characterized. The plasmidome of these strains consists of 13 replicons, ranging in size from 3,378 to 101,077 bp. In silico sequence analyses identified the conserved backbones of these plasmids, composed of genes required for plasmid replication, stable maintenance, and conjugal transfer. Host range analysis revealed that all of the identified plasmids are narrow-host-range replicons, only able to replicate in bacteria of closely related genera (Polaromonas and Variovorax) of the Comamonadaceae family. Special attention was paid to the identification of plasmid auxiliary genetic information, which may contribute to the adaptation of bacteria to environmental conditions occurring in glaciers. Detailed analysis revealed the presence of genes encoding proteins potentially involved in (i) protection against reactive oxygen species, ultraviolet radiation, and low temperatures; (ii) transport and metabolism of organic compounds; (iii) transport of metal ions; and (iv) resistance to heavy metals. Some of the plasmids also carry genes required for the molecular assembly of iron–sulfur [Fe-S] clusters. Functional analysis of the predicted heavy metal resistance determinants demonstrated that their activity varies, depending on the host strain. This study provides the first molecular insight into the mobile DNA of Polaromonas spp. inhabiting polar glaciers. It has generated valuable data on the structure and properties of a pool of plasmids and highlighted their role in the biology of psychrotolerant Polaromonas strains and their adaptation to the environmental conditions of Arctic and Antarctic glaciers

The Doping Effect of Fluorinated Aromatic Solvent on the Rate of Ruthenium Catalysed Olefin Metathesis

A study concerning the effect of using a fluorinated aromatic solvent as the medium for olefin metathesis reactions catalysed by ruthenium complexes bearing N-heterocyclic carbene ligands is presented. The use of fluorinated aromatic hydrocarbons (FAH) as solvents for olefin metathesis reactions catalysed by standard commercially available ruthenium pre-catalysts allows substantially higher yields of the desired products to be obtained,especially in the case of demanding polyfunctional molecules, including natural and biologically active compounds. Interactions between the FAH and the second-generation ruthenium catalysts, which apparently improve the efficiency of the olefin metathesis transformation, have been studied by X-ray structure analysis and computations, as well as by carrying out a number of metathesis experiments. The optimisation of reaction conditions by using an FAH can be regarded as a complementary approach for the design of new improved ruthenium catalysts. Fluorinated aromatic solvents are an attractive alternative medium for promoting challenging olefin metathesis reactions

Marker-independent vibrational spectroscopy imaging recognizes the hypoxia effect in the human brain endothelium

Brain microvascular endothelial cells experience hypoxic conditions in several neurodegenerative disease processes and the underlying mechanisms still need to be explored. Current imaging modalities and biochemical assays require many specific markers that should be detected to identify the hypoxic response, especially at a level of single cells. This study presents a single-cell molecular imaging approach utilizing Fourier-Transform Infrared and Raman spectroscopy. Those methods enable the simultaneous detection of proteins, lipids, and nucleic acids encoded in their unique vibrational fingerprints. By establishing ratiometric estimators, we measured upregulated lipid metabolism, structural changes of proteins and asses DNA:RNA ratio at the single-cell level induced by oxygen depletion. Moreover, this approach allows for analyzing changes within specific cellular compartments, including nuclei, providing a comprehensive understanding of how hypoxia affects cellular functions and metabolism. Our findings pave the way for future investigations into the cellular adaptations to hypoxia in brain endothelial cells, potentially revealing novel therapeutic targets for neurodegenerative diseases

Mammographic density in relation to breast cancer recurrence and survival in women receiving neoadjuvant chemotherapy

ObjectiveThe association between mammographic density (MD) and breast cancer (BC) recurrence and survival remains unclear. Patients receiving neoadjuvant chemotherapy (NACT) are in a vulnerable situation with the tumor within the breast during treatment. This study evaluated the association between MD and recurrence/survival in BC patients treated with NACT.MethodsPatients with BC treated with NACT in Sweden (2005–2016) were retrospectively included (N=302). Associations between MD (Breast Imaging-Reporting and Data System (BI-RADS) 5th Edition) and recurrence-free/BC-specific survival at follow-up (Q1 2022) were addressed. Hazard ratios (HRs) for recurrence/BC-specific survival (BI-RADS a/b/c vs. d) were estimated using Cox regression analysis and adjusted for age, estrogen receptor status, human epidermal growth factor receptor 2 status, axillary lymph node status, tumor size, and complete pathological response.ResultsA total of 86 recurrences and 64 deaths were recorded. The adjusted models showed that patients with BI-RADS d vs. BI-RADS a/b/c had an increased risk of recurrence (HR 1.96 (95% confidence interval (CI) 0.98–3.92)) and an increased risk of BC-specific death (HR 2.94 (95% CI 1.43–6.06)).ConclusionThese findings raise questions regarding personalized follow-up for BC patients with extremely dense breasts (BI-RADS d) pre-NACT. More extensive studies are required to confirm our findings

Insight into heavy metal resistome of soil psychrotolerant bacteria originating from King George Island (Antarctica)

The presence of heavy metals in Antarctica is an emerging issue, especially as (bio)weathering of metal-containing minerals occurs and human influence is more and more visible in this region. Chemical analysis of three soil samples collected from the remote regions of King George Island (Antarctica) revealed the presence of heavy metals (mainly copper, mercury, and zinc) at relatively high concentrations. Physiological characterization of over 200 heavy metal-resistant, psychrotolerant bacterial strains isolated from the Antarctic soil samples was performed. This enabled an insight into the heavy metal resistome of these cultivable bacteria and revealed the prevalence of co-resistance phenotypes. All bacteria identified in this study were screened for the presence of selected heavy metal-resistance genes, which resulted in identification of arsB (25), copA (3), czcA (33), and merA (26) genes in 62 strains. Comparative analysis of their nucleotide sequences provided an insight into the diversity of heavy metal-resistance genes in Antarctic bacteria

Functional significance of CD105-positive cells in papillary renal cell carcinoma

BACKGROUND: CD105 was postulated as a renal cell carcinoma (RCC) stem cell marker, and CD133 as a putative RCC progenitor. Hypoxia, a natural microenvironment that prevails in tumors, was also incorporated into the study, especially in terms of the promotion of hypothetical stem-like cell properties. METHODS: Within this study, we verify the existence of CD105+ and CD133+ populations in selected papillary subtype RCC (pRCC) cell lines. Both populations were analyzed for correlation with stem-like cell properties, such as stemness gene expression, and sphere and colony formation. For the preliminary analysis, several RCC cell lines were chosen (786-O, SMKT-R2, Caki-2, 796-P, ACHN, RCC6) and the control was human kidney cancer stem cells (HKCSC) and renal cells of embryonic origin (ASE-5063). Four cell lines were chosen for further investigation: Caki-2 (one of the highest numbers of CD105+ cells; primary origin), ACHN (a low number of CD105+ cells; metastatic origin), HKCSC (putative positive control), and ASE-5063 (additional control). RESULTS: In 769-P and RCC6, we could not detect a CD105+ population. Hypoxia variously affects pRCC cell growth, and mainly diminishes the stem-like properties of cells. Furthermore, we could not observe the correlation of CD105 and/or CD133 expression with the enhancement of stem-like properties. CONCLUSIONS: Based on this analysis, CD105/CD133 cannot be validated as cancer stem cell markers of pRCC cell lines

Identification of blood immunological biomarkers of SARS-CoV-2 infection during pandemic in Poland

IntoductionT lymphocytes, along with cytokines and chemokines-dependent pathways are primarily responsible for regulating the immune response, controlling inflammation and eliminating viral infections. However, excessive immune activity can lead to pathological effects such as cytokine storm, which may cause severe respiratory distress syndrome and multi-organ damage in COVID-19. The aim of this study was to identify potential biomarkers of SARS-CoV-2 infection that could predict the severity of COVID-19 progression.MethodsThe cohort in this study included 52 hospitalized adult patients with SARS-CoV-2 infection from Warsaw, Poland admitted to the hospital during COVID-19 pandemic (February to November 2021). Based on clinical symptoms, patients were divided into two groups: (i) mild/moderate symptoms (non-severe) – 44 patients and (ii) severe respiratory failure (severe) – 8 patients. The control group consisted of 26 individuals without COVID-19. All COVID-19 patients and healthy controls underwent immunophenotyping of peripheral blood to assess the abundance of T lymphocytes and regulatory T lymphocytes, as well as measurement of selected cytokine and chemokine concentrations in corresponding serum samples. Data analysis was performed using CytoFLEX Flow Cytometer. Results and discussionDecreased percentages of total lymphocytes and T lymphocytes in peripheral blood were observed across all COVID-19 patients, with varying degrees between the non-severe and severe groups. A significant reduction was also noted in double-positive lymphocytes (CD4+CD8+), regulatory T lymphocytes ( CD4+ CD25HiCD127Lo and CD4+CD25HiCD127LoFoxP3+), as well as CD4+CD25+/-, CD4+CD45RA+/-, and CD8+CD45RA+/- subsets. Elevated levels of IL-6, IL-10, IL-17A, IFN-g, CCL2, CXCL8, and CXCL10 were observed in the non-severe and/or severe groups compared to healthy controls. Most importantly, only CXCL10 was significantly elevated in the severe group at admission compared to the non-severe group. In this study, we identified the chemokine CXCL10 as a crucial marker for distinguishing the severe course of COVID-19 from non-severe form at the time of admission. It may serve as an early indicator of diseases progression during hospitalization, potentially allowing prediction of the disease course. Moreover, elevated CXCL10 levels, in combination with decreased total lymphocytes counts and increased levels of IL-6, IL10, IFNg, CCL2 and CXCL9, may represent a more comprehensive biomarker panel suitable for predicting the severity of COVID-19