Search

Whole-genome sequence of Pseudomonas sp. Kongs-67 retrieved from Kongsfjorden, an Arctic fjord, has been investigated to understand the molecular machinery required for microbial association and survival in a polar fjord. The genome size of Kongs-67 was 4.5 Mb and was found to be closely related to the Antarctic P. pelagia strain CL-AP6. This genome encodes for chemotaxis response regulator proteins (CheABB1RR2VWYZ), chemoreceptors (methyl-accepting chemotaxis proteins), and flagellar system proteins (FliCDEFGOPMN, FlhABF, FlgBCDEFGHIJKL, and MotAB proteins) vital in cellular interactions in the dynamic fjord environment. A high proportion of genes were assigned to biofilm formation (pgaABCD operon) and signal transduction protein categories (EnvZ/OmpR, CpxA/CpxR, PhoR/PhoB, PhoQ) indicating that the biofilm formation in Kongs-67 could be tightly regulated in response to the availability of signalling-metabolites. The genome of Kongs-67 encoded for HemBCD, CbiA, CobABNSTOQCDP, and BtuBFR proteins involved in cobalamin biosynthesis and transport along with proteins for siderophore-mediated iron channelling (PchR, Fur protein, FpvA); crucial in a microbial association. The genomes of Arctic strain Kongs-67 and Antarctic strain CL-AP6 were similar which is indicative of retainment of the core genes in the polar Pseudomonas strains that could be vital in conferring evolutionary adaptation for its survival in a polar fjord. Thus, our study contributes to the knowledge on the genetics of a polar Pseudomonas member exhibiting biosynthetic potentials and suggest Pseudomonas sp. Kongs-67 as a suitable candidate for the investigation of functional aspects of molecular adaptations in the polar marine environment.

Genome of Alcanivorax sp. IO_7, an alkane degrading deep-sea bacteria isolated from hydrothermally-influenced Southwest Indian Ridge was sequenced and analysed. Genomic data mining revealed gene clusters for degrading n-alkane and cycloalkanes, including biosurfactant production. The strain was shown to grow on hexadecane as its sole carbon source, supporting the findings of genomic analysis. Presence of cyclohexanone monooxygenase among genomic islands suggest that this strain may have used gene transfer to enhance its hydrocarbon degradation ability. Genes encoding for heavy metal resistance, multidrug resistance and multiple natural product biosynthesis crucial for survival in the hydrothermally influenced deep sea environment were detected. In our comparative genome analysis, it was evident that marine Alcanivorax strains contain a suite of enzymes for n-alkane and haloalkanoate degradation. Comparative genome and genomic synteny analysis provided insights into the physiological features and adaptation strategies of Alcanivorax sp. IO_7 in the deep-sea hydrothermal environment.

Herein we report the isolation of a novel actinomycete, strain MCCB 268T, from the sediment sample collected from a high Arctic fjord Kongsfjorden. MCCB 268T showed greater than 97% 16S rRNA gene sequence similarity with those of Pseudonocardia konjuensis LM 157T (98.06%), Pseudonocardia soli NW8-21 (97.22%) Pseudonocardia endophytica YIM 56035 (97.08%) and Pseudonocardia nantongensis KLBMP 1282 (97.34%) showing that the strain should be assigned to the genus Pseudonocardia. DNA–DNA hybridization with Pseudonocardia konjuensis LM 157T showed only 41.5% relatedness to strain MCCB 268T. The whole genome of the strain MCCB 268T was sequenced. Whole-genome average nucleotide identity, dDDH (%) and genome tree analysis demonstrated that strain significantly differed from other Pseudonocardia species. The G + C content was 70.5 mol%. MCCB 268T exhibited in vitro cytotoxicity and through bioassay guided fractionation followed by HPLC separation a cytotoxic compound (I) was isolated. The compound (I) was identified as 1-acetyl-β-carboline through NMR spectra and high-resolution mass spectrometry. Compound (I) showed cytotoxicity against lung cancer cell line and mode of anticancer activity was found to be through the induction of apoptosis. Based on the genotypic and phenotypic features, MCCB 268T ought to be classified as a novel species under the genus Pseudonocardia for which the name Pseudonocardia cytotoxica sp. nov. is proposed (= CCUG72333T = JCM32718T).

A Gram-stain-negative, rod-shaped bacterial strain designated as 20VBR1T was isolated from a valley glacier (Vestrebroggerbreen) snout ice sample from Ny-Ålesund, Svalbard, Arctic. The colonies were smooth, circular and light creamish on half-strength R2A agar and grew at 10–35 °C (optimum, 20 °C), at pH 6.5–8.0 (optimum, 7.0) and with 0–2.5 % (w/v) NaCl (optimum, 0.5 %). 16S rRNA gene sequence analysis revealed that strain 20VBR1T belonged to the genus Phenylobacterium and was most closely affiliated to Phenylobacterium aquaticum W2-3-4T (97.65 % similarity), Phenylobacterium haematophilum LMG 11050T (97.57 %) and Phenylobacterium koreense Slu-01T (96.91 %). 20VBR1T has a genome size of 4.24 Mb, comprising 4185 predicted genes with a DNA G+C content of 67.86 mol%. DNA–DNA hybridization experiments indicated that the DNA–DNA relatedness between strain 20VBR1T and P. aquaticum KACC 18306T was 41.95±4.36 %, well below the threshold (T and its closest phylogenomic relative, P. aquaticum KACC 18306T, were 78.97 and 22.10 %, respectively. The predominant isoprenoid quinone was ubiquinone (Q-10) and the major polar lipids were phosphatidylglycerol, one unknown phospholipid, one unknown glycolipid and four unidentified polar lipids. The major fatty acids (>10 %) of strain 20VBR1T were summed feature 8 (comprising C18 : 1 ω7c and/or C18 : 1 ω6c), summed feature 3 (comprising C16 : 1 ω6c and/or C16 : 1 ω7c) and C16 : 0. Based on the physiological, biochemical, chemotaxonomic, phylogenetic and phylogenomic analyses, isolate 20VBR1T is considered to represent a novel species of the genus Phenylobacterium , for which the name Phenylobacterium glaciei sp. nov. is proposed. The type strain is 20VBR1T (=JCM 33227 T=DSM 111428 T=MCC 4220 T).

In the present study, we investigated the microbial community composition and their associated metabolic potentials using the 16S rRNA gene (V3-V4) and ITS (ITS1) amplicon sequencing approach in the Patsio glacier. The bacterial community composition was mainly dominated by Bacteroidota (18%-38% of total reads) and Cyanobacteria (9%-30%), along with a rare Candidate phylum Patescibacteria. Ferruginibacter (13%) and Polaromonas (8%) were the most dominant genera identified across the samples known to have potential ecological roles in colonization, driving the functioning of supraglacial habitats. The prevalence of metabolic genes associated with nitrogen, carbon and sulfur cycling processes was identified in the present study. The fungal diversity was dominated by members of unclassified phyla, followed by Ascomycota (up to 6%) and Basidiomycota (up to 4%), in terms of its relative abundance. The relative abundance of Fusarium and Didymella (8%-14%) was higher among the high altitude, cryoconite samples (P1-P5), while Rhodotorula (12%-29%) dominated in the glacial ice debris samples (P6-P8). Thus, our study provides significant insights into dynamics of microbial communities and its potential ecological roles in the changing climate.

A Gram-negative, aerobic, non-motile, oxidase-positive, catalase-positive, rod-shaped bacterium, designated strain MCCB 386T was isolated from sediment samples collected from Kongsfjorden, an Arctic fjord. The strain MCCB 386T showed growth at 4–37 °C (optimum 27°C) in the presence of 1–8% NaCl (w/v, optimum 3.5%) and at pH 6.0–8.0 (optimum pH 7.0). The major fatty acids were C18:1ω7c (54.0%) and 11-methyl C18:1ω7c (22.6%). The dominant respiratory quinone was Q-10. The major polar lipids comprised of phosphatidylcholine (PC), diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphoglycolipid (PGL), one unidentified aminolipid, two glycolipids and two unidentified lipids. The genomic G+C content of the strain MCCB 386T was 68.1 mol%. The 16 S rRNA gene sequences based phylogenetic analysis of MCCB 386T showed that Psychromarinibacter halotolerans YBW34T (95.88%) is the most closely related species. In addition, overall genome relatedness indices (OGRI) of MCCB 386T with closely related strains were lower than threshold level for species and genus delineation. The analysis of Biosynthetic Gene clusters (BGCs) revealed the potential of this strain for production of novel bioactive secondary metabolites. As per polyphasic taxonomic characterisation, strain MCCB 386T represents a novel species of a novel genus for which the name Roseitranquillus sediminis gen. nov., sp. nov. is suggested. The type strain of the species is MCCB 386T (= JCM 33,538T= KACC 21,531T).

Whole-genome sequence of Pseudomonas sp. Kongs-67 retrieved from Kongsfjorden, an Arctic fjord, has been investigated to understand the molecular machinery required for microbial association and survival in a polar fjord. The genome size of Kongs-67 was 4.5 Mb and was found to be closely related to the Antarctic P. pelagia strain CL-AP6. This genome encodes for chemotaxis response regulator proteins (CheABB1RR2VWYZ), chemoreceptors (methyl-accepting chemotaxis proteins), and flagellar system proteins (FliCDEFGOPMN, FlhABF, FlgBCDEFGHIJKL, and MotAB proteins) vital in cellular interactions in the dynamic fjord environment. A high proportion of genes were assigned to biofilm formation (pgaABCD operon) and signal transduction protein categories (EnvZ/OmpR, CpxA/CpxR, PhoR/PhoB, PhoQ) indicating that the biofilm formation in Kongs-67 could be tightly regulated in response to the availability of signalling-metabolites. The genome of Kongs-67 encoded for HemBCD, CbiA, CobABNSTOQCDP, and BtuBFR proteins involved in cobalamin biosynthesis and transport along with proteins for siderophore-mediated iron channelling (PchR, Fur protein, FpvA); crucial in a microbial association. The genomes of Arctic strain Kongs-67 and Antarctic strain CL-AP6 were similar which is indicative of retainment of the core genes in the polar Pseudomonas strains that could be vital in conferring evolutionary adaptation for its survival in a polar fjord. Thus, our study contributes to the knowledge on the genetics of a polar Pseudomonas member exhibiting biosynthetic potentials and suggest Pseudomonas sp. Kongs-67 as a suitable candidate for the investigation of functional aspects of molecular adaptations in the polar marine environment.

Herein we report the isolation of a novel actinomycete, strain MCCB 268

The Southwest Indian Ridge (SWIR) is one of the least explored mid-ocean ridges and contains a high frequency of hydrothermal vents. We examined the bacterial community structure and metabolic potential of surface sediments collected from a sea mount at 2681 m depth and a ridge-flank at 3776 m in SWIR. High throughput 16S rRNA amplicon sequencing combined with Community Level Physiological Profiling (CLPP) revealed that hydrothermal sediments hosted a diverse microbial community with significant difference in structure and function between seamount and ridge-flank. The ridge-flank community was primarily comprised of facultative chemoautotrophic members of Burkholderiales (43.0%) while copiotrophic members of Alteromonadales (56.9%) and Oceanospirillales (14.6%) were dominant in seamount sample. These results coincided with CLPP of microbial community with higher utilization of carbohydrates such as D-cellobiose, β-methyl-D-glucoside, glucose 1-phosophate and pyruvic acid methyl ester observed in seamount. Culture-dependent approach using array of nutrient media enabled the isolation of heterotrophic genera that exhibited ability to degrade refractory organic matter such as phenanthrene, anthracene, pyrene, fluorene and fluoranthene. These results indicate that bacterial community present in the deep-sea hydrothermal sediment can act as bioreactor for mineralization of refractory organic matter. Thus our study emphasize on the significance of polyphasic approach in comprehensive and rapid assessment of physiological and taxonomic characteristics of the deep seabed bacterial community and further suggested that the bacterial community can act as ecological indicators of the metabolic sources prevalent in the ridge environment.

The bacterial reduction of mercury is one of the transformation processes where ionic form (Hg2+) converts into elemental form (Hg0). The biological reduction of mercury is facilitated by the mercuric reductase (merA) gene. The significance of understanding the role of microbial mercury reduction in the Arctic during the changing climate conditions is high as it acts as the sink as well as a source of mercury. The present study was carried out to assess the prevalence of mercury tolerant bacteria and to know the distribution of merA in the Arctic bacterial communities. Citrobacter freundii strain MM7, a psychrotrophic, gram-negative, facultative anaerobic, non-traditional sulphate-reducing bacterium, isolated from the sediments of Kongsfjorden showed tolerance to mercury up to 10.0 mg/L in vitro. Mercury removal experiment confirmed the removal of ∼80% of mercury mediated by plasmid-borne merA gene. Studies using Fourier transform infrared (FTIR) showed the metabolic changes incited by mercury, and the spectroscopic differences reflected that the functional groups like alkynes, aromatic phosphates, organic phosphates, methyl, methylene, and amide groups present in the bacterial surface owe a significant part in Hg biosorption and removal. The present study provides insights on the mercury resistance in an Arctic bacterial strain and suggests the potential application of Citrobacter freundii strain MM7 in the bioremediation of mercury from the natural environment.

The Kongsfjorden, an Arctic fjord is experiencing warming due to increased input of Atlantic water masses. High-throughput sequencing was performed to examine bacterial diversity from the outer and inner zone of the fjord in summer and fall of 2012. A total of 11,999 operational taxonomic units (OTUs) were assigned into 19 known phyla and 5 genera incertae sedis . Significant variation ( p = 0.001, n = 4) was observed between the bacterial community structure of outer and inner fjord while variation between summer and fall was minimum. Proteobacteria was the most abundant phylum (55.9-61.0%) in summer and fall. The most dominant alphaproteobacterial member of this phylum (OTU 263 Pelagibacteriaceae ) contributed maximum to the observed dissimilarity between the outer and inner fjord community. Characterised by relatively fresher and warmer water, glacial meltwater input could be a major source of predominance of OTU 6968 Flavobacteriaceae , OTU 5552 Psychrobacter , OTU 7148 Sphingomonadales and OTU 5011 Loktanella in the inner fjord in summer. Thus, the significant variation in the bacterioplankton community composition of outer and inner fjord indicates strong and localized influence of glacial melt water in shaping the community structure.

For multimedia applications, data are developed and transmitted through the networks. These multimedia data should not be accessed by the unauthorized persons as it contains information. So, in current scenarios image security and privacy become a major issue in communication. In this work, we proposed an advanced encryption scheme based on modified Rubik’s cube algorithm. First, the original image is scrambled using two secret keys, which is generated using logistic function and shift register method, respectively. Then, with XOR operator, rows and columns of the scrambled image are again mixed using various means. Performance of the proposed work is assessed with correlation coefficient and information entropy. From the experimental analysis and security parameter evaluation, it can be observed that the proposed scheme can resist exhaustive attack, statistical attack and differential attack.

Facial Expression Recognition is an extremely interesting topic of research owing to the uniqueness attached to emotions of different humans. Deep Learning is a novel zone within the domain of machine learning which is exceedingly efficient in image classification problems. Methods of Deep Learning, (CNN) Convolutional Neural Networks in particular, have been used with great precision for the purpose of feature extraction. This paper categorizes each facial image into one of the seven human emotion classes by making use of a specially designed Convolutional Neural Network which employs four subsequent sets of layers and a loss function. The model has been trained and tested on the FER2013 data set from the Kaggle Facial Expression Recognition Challenge, which consists of 35,887, 48-by-48-pixel pictures of human faces, which are grayscale in nature, each with a label of one of the 7 emotion categories. The model gives an accuracy of about 64%.

The bacterial community composition of a valley glacier in Svalbard, its pro-glacial channels, and the associated downstream fjord ecosystem was investigated so as to figure out the degree to which downslope transport of microbes from the glacier systems along a hydrological continuum impose an effect on the patterns of diversity in the fjord system. A combination of culture based and high-throughput amplicon sequencing approach was followed which resulted in significant variation (R = 0.873, p = 0.001) in the bacterial community structure between these ecosystems. Dominance of sequences belonging to class β-Proteobacteria was seen in the glacier snow, ice and melt waters (MW) while a relatively higher abundance of OTUs belonging to α-Proteobacteria and Verrucomicrobiae demarcated the fjord waters. Similarity percentage (SIMPER) analysis of the Operational Taxonomic Units (OTUs) showed that OTU 1,105,280 (9.15%) and OTU 331 (6.5%) belonging to Burkholderiaceae (β-proteobacteria) and OTU 101,660 (5.76%) and OTU 520 (5.07%) belonging to Rhodobacteraceae (α-proteobacteria) contributed maximum to the overall dissimilarity between the sampling sites. The bacterial community from the MWs were found to be true signatures of the glacier ecosystem while the Kongsfjorden bacterial fraction mostly represented heterotrophic marine taxa influenced by warm Atlantic waters and presence of organic matter. Significant presence of unknown taxa in the MWs suggests the need to study such unexplored, transient niches for a better understanding of the associated microbial processes. Among the various environmental parameters measured, nutrients (NO3− and SiO42−) were found to exhibit strong association with the MW bacterial community while temperature, trace metals, Cl− and SO42− ions were found to influence the fjord bacterial community. The significant differences in the bacterial community composition between the glacier and the fjord ecosystem suggest the unique nature of these systems which in turn is influenced by the associated environmental parameters.

The whole genome of Alteromonas pelagimontana 5.12T, a psychrotolerant deep-sea bacterium isolated from the sediment sample of eastern Southwest Indian Ridge, was sequenced and analysed for understanding its metabolic capacities and biosynthesis potential of natural products. The circular genome contained 4.3 Mb with a GC content of 42.6 mol%. Genomic data mining revealed a gene cluster for heavy metal resistance (czcABC, acrB, arsR1, copA, nikA, mntH, mntP), exopolysaccharides (EPS; epsCDEFHLM) and polyhydroxyalkanoates (PHA; phbC) production, as well as genes involved in complex polysaccharide degradation. Genes that could allow strain 5.12T to cope with acid stress (ibaG) and heat shock (ibpA, hslR) were observed along with ten chaperone-encoding genes which could possibly play vital role in adaptability of this strain to the hydrothermally influenced environment. Gene clusters for secondary metabolite production such as bacteriocin and arylpolyene were also predicted. Thus, genome sequencing and data mining provided insights into the molecular mechanisms involved in the adaptation to hydrothermally influenced deep-sea environment that could promote further experimental exploration.

In present work, an encryption scheme is proposed which involves confusion and diffusion process for secure data transmission. The proposed algorithm involves the use of chaotic map, Arnold Cat Map, to produce the confused image. Furthermore, S-box transformation and XOR operation is used to provide diffusion. The process involves the use of 128-bit random key, the bytes of which is substituted with the values of s-box. The substituted values are then applied to the process of row shift and mix column to obtain the final encryption key. This key is XORed with the confused image to obtain the final encrypted image.

R peak is an important parameter of ECG for monitoring the cardiac health. In this paper we present R peak detection algorithm from electrocardiogram (ECG) signal using Empirical Mode Decomposition (EMD) with combination of Shannon Energy Envelope. In this algorithm the ECG signal is decomposed by using the EMD and for highlighting the QRS complex we have take summation of first three Intrinsic Mode Functions (IMFs). The Shannon energy envelope is used for obtaining the envelope for detection of R peaks. MIT-BIH arrhythmia database is used for evaluation of proposed algorithm and compared with existing techniques. The comparison results shows that the proposed methodology is superior providing sensitivity of 97.85 %, positive predictive rate of 98.15% and accuracy of 98.19% of our proposed algorithm.

In today's scenario, the usage of images has become very popular in many applications like military, medical, social media and industries. Sensitive images are communicated through insecure networks. Therefore some methods are required by which the images can be transmitted securely over the network. The proposed algorithm is a modified image encryption algorithm based on Arnold Cat Map. The scheme involves confusion process in which the position of each pixel of the image is shuffled using Cat Map. The shuffling of pixel position leads to the generation of a permuted image which is secured for transmission. Security analysis for the suggested scheme is performed using correlation coefficient (which is 0.6402 horizontally and 0.6954 vertically) and information entropy (which is 7.9504) analysis.

Background: Left ventricular (LV) dyssynchrony frequently occurs in patients with heart failure (HF). QRS ≥ 120 ms is a surrogate marker of electrical dyssynchrony, which occurs in only 30% of HF patients. In contrary, in those with normal QRS (nQRS) duration, LV dyssynchrony has been reported in 20-50%. This study was carried out to investigate the role of fragmented QRS (fQRS) on the surface electrocardiography (ECG) as a marker of electrical dyssynchrony to predict the presence of significant intraventricular dyssynchrony (IVD) by subsequent echocardiographic assessment. Methods: A total of 226 consecutive patients with non-ischemic cardiomyopathy were assessed for fQRS on surface ECG as defined by presence of an additional R wave (R prime), notching in nadir of the S wave, notching of R wave, or the presence of more than one R prime (fragmentation) in two contiguous leads corresponding to a major myocardial segment. Tissue Doppler imaging (TDI) was performed in the apical views (four-chamber, two-chamber and long-axis) to analyze all 12 segments at both basal and middle levels. Time-to-peak myocardial sustained systolic (Ts) velocities were calculated. Significant systolic IVD was defined as Ts-SD > 32.6 ms as known as “Yu index”. Result: Of the total patients, 112 had fQRS (49.5%), while 114 had nQRS (50.5%) with male dominance (M/F = 71:29). Majority of patients were in NYHA class II (n = 122, 54%) followed by class III (n = 83; 37%), and class IV (n = 21; 9%). There were no significant differences among both groups for baseline parameters except higher QRS duration (102.42 ± 14.05 vs. 91.10 ± 13.75 ms; P = 0.001), higher Yu index (35.64 ± 12.79 vs. 20.45 ± 11.17; P = 0.01) and number of patients with positive Yu index (78.6% vs. 21.1%; P = 0.04) in group with fQRS compared with group with nQRS. fQRS complexes had 84.61% sensitivity and 80.32% specificity with positive predictive value of 78.6% and negative predictive value of 85.9% to detect IVD. On detailed segmental analysis for fQRS distribution, inferior segment had maximum (37%), followed by anterior (23%), lateral (19%), inferior and lateral (11%), anterior and inferior (8%), and anterior and lateral (2%). Among 104 patients with significant dyssynchrony, 88 patients (84.6%) had fQRS in the dyssynchronic segment. Conclusion: Fragmentation of QRS complex is an important predictor of electro-mechanical dyssynchrony. It is also helpful in localizing the dyssynchronous segment. In future, larger studies may be carried out to investigate the role of fQRS as a predictor of response to cardiac resynchronization therapy (CRT) in this subgroup of HF patients with narrow QRS. Cardiol Res. 2016;7(4):140-145 doi: http://dx.doi.org/10.14740/cr495w

A novel exopolysaccharide-producing strain, designated as 5.12T, was isolated from a sediment sample from the Southwest Indian Ridge, Indian Ocean. The strain was Gram-stain-negative, motile, strictly aerobic, and oxidase- and catalase-positive. It grew optimally at 35 °C, at pH 6.0 and in the presence of 3.5 % (w/v) NaCl. Its major isoprenoid quinone was ubiquinone-8 (Q-8) and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c), C16 : 0 and C18 : 1ω7c were the major cellular fatty acids. The DNA G+C content was 46.1 mol%. 16S rRNA gene sequence analysis suggested that strain 5.12T is a member of the genus Alteromonas . Strain 5.12T exhibited close 16S rRNA gene sequence similarity to Alteromonas lipolytica JW12T (96.1 %), Alteromonas hispanica F-32T (95.9 %), Alteromonas confluentis DSSK2-12T (95.9 %), Alteromonas litorea TF-22T (95.6 %) and Alteromonas mediterranea DET (95.5 %). Strain 5.12T contained phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. Owing to significant differences in the 16S rRNA gene sequences, as well as the phenotypic and chemotaxonomic characteristics, the novel isolate described here merits classification as a representative of a novel species of the genus Alteromonas , for which the name Alteromonas pelagimontana sp. nov. is proposed. The type strain of this species is 5.12T (LMG 29661T= MCC 3250T).

After screening marine actinomycetes isolated from sediment samples collected from the Arctic fjord Kongsfjorden for potential anticancer activity, an isolate identified as Streptomyces artemisiae MCCB 248 exhibited promising results against the NCI-H460 human lung cancer cell line. H460 cells treated with the ethyl acetate extract of strain MCCB 248 and stained with Hoechst 33342 showed clear signs of apoptosis, including shrinkage of the cell nucleus, DNA fragmentation and chromatin condensation. Further to this treated cells showed indications of early apoptotic cell death, including a significant proportion of Annexin V positive staining and evidence of DNA damage as observed in the TUNEL assay. Amplified PKS 1 and NRPS genes involved in secondary metabolite production showed only 82% similarity to known biosynthetic genes of Streptomyces, indicating the likely production of a novel secondary metabolite in this extract. Additionally, chemical dereplication efforts using LC–MS/MS molecular networking suggested the presence of a series of undescribed tetraene polyols. Taken together, these results revealed that this Arctic S. artemisiae strain MCCB 248 is a promising candidate for natural products drug discovery and genome mining for potential anticancer agents. Electronic supplementary material The online version of this article (doi:10.1007/s13205-017-0610-3) contains supplementary material, which is available to authorized users.

Idiomarina sp. strain 5.13, able to produce biopolymer and exopolysaccharide, was isolated from a sediment sample collected from the Southwest Indian Ridge, Indian Ocean. Analysis of its draft genome sequence provides insights into its remarkable stress tolerance and offers the genetic basis for harnessing the biotechnological potential of this strain.

Bacterial production, respiration and metabolic diversity were measured up to 120 m depth in the Sub-Antarctic Front (SAF) and Polar Fronts I and II (PFI and PFII) of the Indian Ocean sector of the Southern Ocean during 2010 Austral Summer. Prokaryotic cell count was maximum at PFI and PFII (~109 cells L−1) and minimum at SAF (~107 cells L−1). Furthermore, integrated bacterial production was higher at PFI (1.07 mg C m−2 h−1) and PFII (0.72 mg C m−2 h−1) compared to SAF (0.61 mg C m−2 h−1). At PFII, integrated bacterial growth efficiency was higher (8.96) compared to PFI (7.42) and SAF (7.17), signifying that the net contribution of PFII to the microbial loop could be relatively pronounced. Enhanced cell numbers and production at polar fronts indicate that the dissolved organic matter could be converted to secondary biomass through the microbial loop. However, integrated bacterial respiration rate at PFII (0.83 mg C m−2 h−1) was lower than that at PFI (1.84 mg C m−2 h−1) resulting in higher growth efficiency at PFII. Metabolic flexibility at SAF was clearly brought about by utilization of carboxylic acids like D-malic acid and itaconic acid, and carbohydrates like N-acetyl D-glucosamine, D-cellobiose and D-lactose. Utilization of amino acids like glycyl L-glutamic acid and L-threonine, and an amine, phenylethylamine, was critical in determining the metabolic variability at PFI. PFII hosted microbes that utilized phenolic compounds (2-hydroxy benzoic acid and 4-hydroxy benzoic acid) and polymers (like Tween 80). Utilization of polyols over carbohydrates in polar waters indicates a niche with lesser influence of the Antarctic melt waters on the bacterioplankton metabolism.

This study addresses factors governing nitrification and denitrification rates, along with the abundance of the bacterial groups likely involved in these activities, in Kongsfjorden, an Arctic fjord at Ny-Alesund, Svalbard. The fjord was sampled three times during the month of March 2008 as day length and direct solar radiation increased. Although initially well mixed, cooler and more saline, the fjord became stratified, warmer and less saline during late March. The concentrations of NH4 + (4.4 ± 1.6 to 6 ± 1.6 μM) and NO2 − (1 ± 0.3 to 1.2 ± 0.4 μM) increased progressively with the decrease in NO3 − (6.1 ± 1.3 to 3.8 ± 1.5 μM), reflecting the onset of primary productivity. Nitrification rates and the culturable population of nitrifiers decreased significantly from 1.6 ± 0.9 to 0.4 ± 0.1 ng at NH4 +-N l−1 h−1 and 5.1 ± 0.3 × 102 to 29 ± 14 cells l−1, respectively. In contrast, denitrification rates increased (2.4 ± 0.5 to 4.6 ± 1.3 ng-at NO3 −-N l−1 h−1), although the abundance of culturable denitrifiers did not vary significantly. A significant correlation of nitrifiers with NO3 − during early March (p

Kongsfjorden is a glacial fjord in the Arctic that is influenced by both Atlantic and Arctic water masses. In the present report retrievable heterotrophic bacteria isolated from two distinct zones (outer and inner fjord) of Kongsfjorden was studied during summer to fall of 2012. 16S rRNA gene sequences of the retrievable heterotrophic bacteria corresponded to γ-proteobacteria (13 phylotypes), α-proteobacteria (3 phylotypes), Bacteroidetes (4 phylotypes) and Actinobacteria (2 phylotypes). The heterotrophic bacterial community structure was fundamentally different in different months which could be linked to changes in the water masses and/or phytoplankton bloom dynamics. It is hypothesized that monitoring the retrievable heterotrophic bacterial assemblage in the fjord would give valuable insights into the complex ecological role they play under extreme and dynamic conditions.

The year 2012 began with reports on the completion of drilling over the largest subglacial lake of Antarctica, Lake Vostok. It has been sealed from free exchange with the atmosphere for ∼420,000 years, making it a potentially rich and largely unexplored storehouse of genetic information for solving evolutionary queries. Indirect evidence suggests that many impediments exist in the subglacial environment, such as high oxygen tension, low inorganic and organic nutrient concentrations, etc., whereas analysis of glacial and accretion ice from Vostok also implies that the elemental requirements for microbial growth could be satisfied in the lake by many possible electron donors (like H2, Fe2+ and NO 2 − ). Recent reports on the recovery of the longest ever ice core of ∼3,769 m open up a new window for answering many questions about microbiological life in extremes, evolution, and adaptations. This review attempts to present an updated understanding on the potential significance of subglacial environments in unraveling the mystery of evolution of life.

We report the expression pattern of heat shock proteins (HSPs) in an Antarctic psychrotrophic strain of Cellulosimicrobium cellulans (DSM 22151) by comparing with its mesophilic counterpart (DSM 43879T) at different temperatures. In both strains, the synthesis of HSPs declined with growth phase. The Antarctic isolate could upregulate 60 kDa, 52 kDa and 41.6 kDa HSPs at 60°C while for its mesophilic counterpart, regulation was restricted to a 64 kDa fraction. The highly unstable nature of this fraction could have led to the impaired thermotolerance exhibited by the mesophilic strain. The downshift of thermal shock from 60°C to 45°C resulted in further upregulation of HSPs in the psychrotrophic strain, while there was no marked variation in the mesophilic strain. This work highlights the significance of a 60 kDa protein in the Antarctic strain of C. cellulans and also indicates the role of a 52 kDa protein in the previously reported heat shock response. Contrary to expectations, the psychrotrophic strain was found to have better mechanisms to tolerate higher temperatures—a property that could give valuable insights into the evolution and adaptation of cold-adapted bacteria.

The significance of freshwater systems in global manganese cycles is well appreciated. Yet, the polar systems, which encompass the largest freshwater repository in the world, have been least studied for their role in manganese cycling. Here, we present results from a study that was conducted in the brackish water lakes in the Larsemann Hills region (east Antarctica). The rate of in situ manganese oxidation ranged from 0.04 to 3.96 ppb day−1. These lakes harbor numerous manganese-oxidizing bacteria (105 to 106 CFU l−1), predominantly belonging to genera Shewanella, Pseudomonas and an unclassified genus in the family Oxalobacteriaceae. Experiments were conducted with representatives of predominant genera to understand their contribution to Mn cycling and also to assess their metabolic capabilities in the presence of this metal. In general, the total and respiring cell counts were stimulated to a maximum when the growth medium was amended with 10 mM manganese. The addition of manganese promoted the use of d-mannitol, maltose, etc., but inhibited the use of maltotriose, l-serine and glycyl l-glutamic acid. The bacterial isolates were able to catalyze both the redox reactions in manganese cycling. In vitro manganese oxidation rates ranged from 3 to 147 ppb day−1, while manganese reduction rates ranged from 35 to 213 ppb day−1. It was also observed that the maximum stimulation of manganese oxidation occurred in the presence of cobalt (81 ± 57 ppb day−1), rather than iron (37 ± 16 ppb day−1) and nickel (40 ± 47 ppb day−1). Our studies suggest that cobalt could have a more profound role in manganese oxidation, while nickel promoted manganese reduction in polar aquatic systems.

The phytoplankton pigment indices were used to characterize the spatial succession of the community composition in the frontal regions of the subtropical front (STF), sub-Antarctic front (SAF), and polar front (PF) in the Indian Ocean sector of the Southern Ocean during austral summer 2013. Diagnostic indices revealed that the flagellates were dominant in STF (51%) and progressively declined toward SAF (39%) and PF (11%). Similarly, the prokaryotes were highest in STF (43%) and decreased to SAF (32%) and PF (28%). In contrast, the diatoms were gradually increased from STF (6%) to SAF (29%) and PF (61%). The variability of flagellates and diatoms from the STF to PF is attributed to the variability of photosynthetically available radiation, sea surface temperature, and sea surface wind speed. The in-situ pigment indices were then compared to the NASA Ocean Biogeochemical model that shows the similar patterns of frontal community distribution except their magnitude. Similarly, the satellite retrieved phytoplankton biomass (chlorophyll a) was checked for its consistency after comparing with the in-situ observations and the result shows underestimation of satellite measured values. The result suggests that the conjunctive analysis of in-situ, satellite, and model archive is suitable to study the impact of climate variability on the structure of marine ecosystems.

Metal tolerant bacterial strains viz Bacillus cereus (RS-1), Bacillus sp. (RS-2) and Chromohalobacter beijerinckii (RS-3) were isolated from the surface sediments of a solar saltern in Ribandar Goa, situated in the vicinity of the Mandovi estuary influenced by mining activities. RS-1 that showed optimal growth at 20 psu salinity was tolerant to 10 mM Co2+ while hypersaline isolates RS-2 (100 psu) and RS-3 (200 psu) were tolerant to Ni2+ and Mn2+ at 1 mM and 10 mM respectively. Experimental studies revealed that growth was stimulated at low concentrations of metal amendments for all the isolates. Growth of RS-1 was stimulated by ~450% on addition of 100 µM Co2+ whereas for RS-2 and RS-3 it was at 100 µM Ni2+ (70%) and 5 mM Mn2+ (450%). The stimulation in growth was coupled to a dip in respiration rates for the isolates RS-1 and RS-3 when compared to metal unamended controls. The respiration rates for RS-1 and RS-3 during peak growth in the presence of metal were 17.0 and 27.5 compared to the controls which were 24.7 and 473.4 pg formazan cell-1 day-1 respectively. Presence of Ni2+ stimulated the respiration rate (26%) in RS-2 when compared to the control (417.4 pg formazan cell-1 day-1). Co2+ and Mn2+ had a significant negative impact on the utilization of carbohydrates and carboxylic acids in RS-1 and RS-3 respectively. Ni2+ had a stimulatory effect on the utilization of BIOLOG GP2 substrates by RS-2. The phenotypic expressions observed above were correlated with the changes in whole cell protein profiles in the presence and absence of added metal. Addition of Co2+ to RS-1 resulted in a significant up-regulation of 57 kDa fraction while there was a conspicuous down-regulation of 29 kDa protein. The major protein fraction up-regulated in RS-2 in the presence of Ni2+ was a 59 kDa protein while most of the fractions were down-regulated. In RS-3, the addition of Mn2+ at 10, 100 and 1000 µM up-regulated a 50 kDa protein while the 53 kDa fraction was down-regulated. This study relates the metal induced regulation of proteins to phenotypic variations encountered in growth and substrate utilization.

The diversity and abundance of retrievable pelagic heterotrophic bacteria in Kongsfjorden, an Arctic fjord, was studied during the summer of 2011 (June, August, and September). Retrievable bacterial load ranged from 10 3 to 10 7 CFU L −1 in June, while it was 10 4 –10 6 CFU L −1 in August and September. Based on 16S rRNA gene sequence similarities, a higher number of phylotypes was observed during August (22 phylotypes) compared to that during June (6 phylotypes) and September (12 phylotypes). The groups were classified into four phyla: Firmicutes, Actinobacteria, Proteobacteria , and Bacteroidetes. Bacteroidetes was represented only by a single member Leewenhoekiella aequorea during the three months and was dominant (40%) in June. However, this dominance changed in August to a well-known phytopathogenic species Rhodococcus fascians (32%), which could be a result of decrease in the phytoplankton biomass following the secondary bloom. It is the first report of Halomonas titanicae isolation from the Arctic waters. It showed an increase in its abundance with the intrusion of Atlantic water into Kongsfjorden. Increased abundance of Psychrobacter species in the late summer months coincided with the presence of cooler waters. Thus, the composition and function of heterotrophic bacterial community was fundamentally different in different months. This could be linked to the changes in the water masses and/or phytoplankton bloom dynamics occurring in Arctic summer.