scholarly journals Growth and Grazing Mortality Rates of Phylogenetic Groups of Bacterioplankton in Coastal Marine Environments

2005 ◽  
Vol 71 (11) ◽  
pp. 6799-6807 ◽  
Author(s):  
Taichi Yokokawa ◽  
Toshi Nagata

ABSTRACT Dilution culture experiments were conducted in western North Pacific coastal regions to determine growth and grazing mortality rates of bacterial phylogenetic groups (α-, β-, and γ-proteobacteria and the Cytophaga-Flavobacter cluster) detected by fluorescent in situ hybridization. Growth rates varied greatly (1.2- to 4.0-fold) among different groups, and they were related to environmental variables (chlorophyll a concentrations and temperature) in a group-specific fashion. Growth rates of α-proteobacteria, the most abundant group in all the samples examined, were generally lower than those of less abundant groups, including the Cytophaga-Flavobacter cluster and γ-proteobacteria. Grazing mortality rates and mean cell volumes varied little among different groups. These results provide insights into factors that affect distributions of different groups, but growth and grazing mortality alone did not fully explain bacterial community compositions at a broad phylogenetic level.

2005 ◽  
Vol 71 (4) ◽  
pp. 1709-1716 ◽  
Author(s):  
Cecilia Alonso ◽  
Jakob Pernthaler

ABSTRACT It has been hypothesized that the potential for anaerobic metabolism might be a common feature of bacteria in coastal marine waters (L. Riemann and F. Azam, Appl. Environ. Microbiol. 68: 5554-5562, 2002). Therefore, we investigated whether different phylogenetic groups of heterotrophic picoplankton from the coastal North Sea were able to take up a simple carbon source under anoxic conditions. Oxic and anoxic incubations (4 h) or enrichments (24 h) of seawater with radiolabeled glucose were performed in July and August 2003. Bacteria with incorporated substrate were identified by using a novel protocol in which we combined fluorescence in situ hybridization and microautoradiography of cells on membrane filters. Incorporation of glucose under oxic and anoxic conditions was found in α-Proteobacteria, γ-Proteobacteria, and the Cytophaga-Flavobacterium cluster of the Bacteroidetes at both times, but not in marine Euryarchaeota. In July, the majority of cells belonging to the α-proteobacterial Roseobacter clade showed tracer incorporation both in oxic incubations and in oxic and anoxic enrichments. In August, only a minority of the Roseobacter cells, but most bacteria affiliated with Vibrio spp., were able to incorporate the tracer under either condition. A preference for glucose uptake under anoxic conditions was observed for bacteria related to Alteromonas and the Pseudoalteromonas-Colwellia group. These genera are commonly considered to be strictly aerobic, but facultatively fermentative strains have been described. Our findings suggest that the ability to incorporate substrates anaerobically is widespread in pelagic marine bacteria belonging to different phylogenetic groups. Such bacteria may be abundant in fully aerated coastal marine surface waters.


2001 ◽  
Vol 47 (7) ◽  
pp. 601-607 ◽  
Author(s):  
Jonas Långmark ◽  
Nicholas J Ashbolt ◽  
Ulrich Szewzyk ◽  
Thor Axel Stenström

Historically, Cholodny-Rossi buried glass slide techniques have been used to study the microbiota of subsurface environments, yet the bias of such a technique has not been compared against direct sand extraction using modern in situ probing. Over a period of 34 wk, four separate 4-m-deep sand columns receiving raw lake water were examined to compare direct extraction of sand filter biofilm material against in situ glass slide biofilms. Significantly different DAPI direct counts and fluorescent in situ hybridization signals for major phylogenetic groups were observed. Not only were lower proportions (P < 0.001) of EUB338-probed DAPI cells observed on in situ glass slides, but also fewer γ-Proteobacteria (12%–21%) and more α-Proteobacteria (16%–33%) when compared to direct sand extracts. Hence, investigators of the microbial ecology of even simple sand biofilms must consider the inherent biases from "accepted" methods and seek further independent methods to identify those which may be most accurate.Key words: sand filter, biofilms, in situ hybridization, groundwater recharge.


2007 ◽  
Vol 177 (4S) ◽  
pp. 596-597
Author(s):  
Joseph P. Alukal ◽  
Bobby B. Najari ◽  
Wilson Chuang ◽  
Lata Murthy ◽  
Monica Lopez-Perdomo ◽  
...  

Blood ◽  
1992 ◽  
Vol 80 (4) ◽  
pp. 1033-1038 ◽  
Author(s):  
CM Price ◽  
EJ Kanfer ◽  
SM Colman ◽  
N Westwood ◽  
AJ Barrett ◽  
...  

Abstract Fluorescent in situ hybridization has become a useful technique by which chromosomal abnormalities may be shown in interphase cells. We present a dual-fluorescence method whereby a chromosomal and immunophenotypic marker can be visualized simultaneously in the same interphase cell. Two patients with the myeloproliferative disorder polycythemia vera and trisomy for chromosome 8 have been studied using this technique and selective involvement of the myeloid and erythrocyte lineages has been shown by the detection of the trisomy in immunophenotyped cells. Simultaneous analysis of genotype and immunophenotype in individual cells from patients with myeloproliferative disorders or leukemia may help identify the developmental and lineage status of cells in which molecular alterations have resulted in clonal advantage.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Wenjun Li ◽  
Xiaofang Li

Abstract Background Mine tailings are hostile environment. It has been well documented that several microbes can inhabit such environment, and metagenomic reconstruction has successfully pinpointed their activities and community structure in acidic tailings environments. We still know little about the microbial metabolic capacities of alkaline sulphidic environment where microbial processes are critically important for the revegetation. Microbial communities therein may not only provide soil functions, but also ameliorate the environment stresses for plants’ survival. Results In this study, we detected a considerable amount of viable bacterial and archaeal cells using fluorescent in situ hybridization in alkaline sulphidic tailings from Mt Isa, Queensland. By taking advantage of high-throughput sequencing and up-to-date metagenomic binning technology, we reconstructed the microbial community structure and potential coupled iron and nitrogen metabolism pathways in the tailings. Assembly of 10 metagenome-assembled genomes (MAGs), with 5 nearly complete, was achieved. From this, detailed insights into the community metabolic capabilities was derived. Dominant microbial species were seen to possess powerful resistance systems for osmotic, metal and oxidative stresses. Additionally, these community members had metabolic capabilities for sulphide oxidation, for causing increased salinity and metal release, and for leading to N depletion. Conclusions Here our results show that a considerable amount of microbial cells inhabit the mine tailings, who possess a variety of genes for stress response. Metabolic reconstruction infers that the microbial consortia may actively accelerate the sulphide weathering and N depletion therein.


2021 ◽  
Author(s):  
Elizabeth B Lamont ◽  
Andrew J Yee ◽  
Stuart L Goldberg ◽  
David S Siegel ◽  
Andrew D Norden

Abstract Genomic biomarkers inform treatment in multiple myeloma (MM) making patient clinical data a potential window into MM biology. We evaluated de novo MM patients for associations between specific MM cytogenetic patterns and prior cancer history. Analyzing a MM real-world dataset (RWD), we identified a cohort of 1,769 patients with fluorescent in-situ hybridization (FISH) cytogenetic testing at diagnosis. Fully 241 patients (0.14) had histories of prior cancer(s). Amplification of the long arm of chromosome 1 [amp(1q)] varied by prior cancer history (0.31 with prior cancer vs 0.24 without; p = .02). No other MM translocations, amplifications, or deletions were associated with prior cancers. Amp(1q) and cancer history remained strongly associated in a logistic regression adjusting for patient demographic and disease attributes. The results merit follow-up regarding carcinogenic treatment effects and screening strategies for second malignancies. Broadly the findings suggest analyses of patient-level phenotypic-genomic RWD may accelerate cancer research through hypothesis generating studies.


2021 ◽  
pp. 112067212110307
Author(s):  
Raquel María Moral ◽  
Carlos Monteagudo ◽  
Javier Muriel ◽  
Lucía Moreno ◽  
Ana María Peiró

Introduction: Conjunctival melanoma is extremely rare in children and has low rates of resolution. Definitive histopathological diagnosis based exclusively on microscopic findings is sometimes difficult. Thus, early diagnosis and adequate treatment are essential to improve clinical outcomes. Clinical case: We present the first case in which the fluorescent in situ hybridization (FISH) diagnostic technique was applied to a 10-year-old boy initially suspected of having amelanotic nevi in his right eye. Based on the 65% of tumor cells with 11q13 (CCND1) copy number gain and 33% with 6p25 (RREB1) gain as measured by the FISH analysis, and on supporting histopathological findings, the diagnosis of conjunctival melanoma could be made. Following a larger re-excision, adjuvant therapy with Mitomycin C (MMC), cryotherapy and an amniotic membrane graft, the patient has remained disease-free during 9 years of long-term follow-up. Case discussion: Every ophthalmologist should remember to consider and not forget the possibility of using FISH analyses during the differential diagnosis of any suspicious conjunctival lesions. Genetic techniques, such as FISH, have led to great advances in the classification of ambiguous lesions. Evidence-based guidelines for diagnosing conjunctival melanoma in the pediatric population are needed to determine the most appropriate strategy for this age group.


Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 437-446
Author(s):  
Ron Hochstenbach ◽  
Harry Harhangi ◽  
Karin Schouren ◽  
Petra Bindels ◽  
Ron Suijkerbuijk ◽  
...  

Abstract We have found that defective gypsy retrotransposons are a major constituent of the lampbrush loop pair Nooses in the short arm of the Y chromosome of Drosophila hydei. The loop pair is formed by male fertility gene Q during the primary spermatocyte stage of spermatogenesis, each loop being a single transcription unit with an estimated length of 260 kb. Using fluorescent in situ hybridization, we show that throughout the loop transcripts gypsy elements are interspersed with blocks of a tandemly repetitive Y-specific DNA sequence, ay1. Nooses transcripts containing both sequence types show a wide size range on Northern blots, do not migrate to the cytoplasm, and are degraded just before the first meiotic division. Only one strand of ay1 and only the coding strand of gypsy can be detected in the loop transcripts. However, as cloned genomic DNA fragments also display opposite orientations of ay1 and gypsy, such DNA sections cannot be part of the Nooses. Hence, they are most likely derived from the flanking heterochromatin. The direction of transcription of ayl and gypsy thus appears to be of a functional significance.


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