Mountain stoneflies may tolerate warming streams: evidence from organismal physiology and gene expression

AbstractRapid glacier recession is altering the physical conditions of headwater streams. Stream temperatures are predicted to rise and become increasingly variable, putting entire meltwater-associated biological communities at risk of extinction. Thus, there is a pressing need to understand how thermal stress affects mountain stream insects, particularly where glaciers are likely to vanish on contemporary timescales. In this study, we tested the critical thermal maximum (CTMAX) of stonefly nymphs representing multiple species and a range of thermal regimes in the high Rocky Mountains, USA. We then collected RNA-sequencing data to assess how organismal thermal stress translated to the cellular level. Our focal species included the meltwater stonefly, Lednia tumana, which was recently listed under the U.S. Endangered Species Act due to climate-induced habitat loss. For all study species, critical thermal maxima (CTMAX > 20°C) far exceeded the stream temperatures mountain stoneflies experience (< 10°C). Moreover, while evidence for a cellular stress response was present, we also observed constitutive expression of genes encoding proteins known to underlie thermal stress (i.e., heat shock proteins) even at low temperatures that reflected natural conditions. We show that high-elevation aquatic insects may not be physiologically threatened by short-term exposure to warm temperatures and that longer term physiological responses or biotic factors (e.g., competition) may better explain their extreme distributions.

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Molecular basis of ciliary defects caused by compound heterozygous IFT144/WDR19 mutations found in cranioectodermal dysplasia

Human Molecular Genetics ◽

10.1093/hmg/ddab034 ◽

2021 ◽

Author(s):

Yamato Ishida ◽

Takuya Kobayashi ◽

Shuhei Chiba ◽

Yohei Katoh ◽

Kazuhisa Nakayama

Keyword(s):

Protein Trafficking ◽

Primary Cilia ◽

Intraflagellar Transport ◽

Missense Variant ◽

Cellular Level ◽

Compound Heterozygous ◽

Hypomorphic Allele ◽

Genes Encoding ◽

Specific Proteins ◽

Compound Heterozygous Mutations

Abstract Primary cilia contain specific proteins to achieve their functions as cellular antennae. Ciliary protein trafficking is mediated by the intraflagellar transport (IFT) machinery containing the IFT-A and IFT-B complexes. Mutations in genes encoding the IFT-A subunits (IFT43, IFT121/WDR35, IFT122, IFT139/TTC21B, IFT140, and IFT144/WDR19) often result in skeletal ciliopathies, including cranioectodermal dysplasia (CED). We here characterized the molecular and cellular defects of CED caused by compound heterozygous mutations in IFT144 [the missense variant IFT144(L710S) and the nonsense variant IFT144(R1103*)]. These two variants were distinct with regard to their interactions with other IFT-A subunits and with the IFT-B complex. When exogenously expressed in IFT144-knockout (KO) cells, IFT144(L710S) as well as IFT144(WT) rescued both moderately compromised ciliogenesis and the abnormal localization of ciliary proteins. As the homozygous IFT144(L710S) mutation was found to cause autosomal recessive retinitis pigmentosa, IFT144(L710S) is likely to be hypomorphic at the cellular level. In striking contrast, the exogenous expression of IFT144(R1103*) in IFT144-KO cells exacerbated the ciliogenesis defects. The expression of IFT144(R1103*) together with IFT144(WT) restored the abnormal phenotypes of IFT144-KO cells. However, the coexpression of IFT144(R1103*) with the hypomorphic IFT144(L710S) variant in IFT144-KO cells, which mimics the genotype of compound heterozygous CED patients, resulted in severe ciliogenesis defects. Taken together, these observations demonstrate that compound heterozygous mutations in IFT144 cause severe ciliary defects via a complicated mechanism, where one allele can cause severe ciliary defects when combined with a hypomorphic allele.

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Regulatory Mechanisms Controlling Expression of the DAN/TIR Mannoprotein Genes During Anaerobic Remodeling of the Cell Wall in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/157.3.1169 ◽

2001 ◽

Vol 157 (3) ◽

pp. 1169-1177

Author(s):

Natalia E Abramova ◽

Brian D Cohen ◽

Odeniel Sertil ◽

Rachna Kapoor ◽

Kelvin J A Davies ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Consensus Sequence ◽

Ectopic Expression ◽

Constitutive Expression ◽

Anaerobic Growth ◽

Zinc Cluster ◽

Sterol Transport ◽

Genes Encoding ◽

Altered Regulation ◽

Repression Domain

Abstract The DAN/TIR genes of Saccharomyces cerevisiae encode homologous mannoproteins, some of which are essential for anaerobic growth. Expression of these genes is induced during anaerobiosis and in some cases during cold shock. We show that several heme-responsive mechanisms combine to regulate DAN/TIR gene expression. The first mechanism employs two repression factors, Mox1 and Mox2, and an activation factor, Mox4 (for mannoprotein regulation by oxygen). The genes encoding these proteins were identified by selecting for recessive mutants with altered regulation of a dan1::ura3 fusion. MOX4 is identical to UPC2, encoding a binucleate zinc cluster protein controlling expression of an anaerobic sterol transport system. Mox4/Upc2 is required for expression of all the DAN/TIR genes. It appears to act through a consensus sequence termed the AR1 site, as does Mox2. The noninducible mox4Δ allele was epistatic to the constitutive mox1 and mox2 mutations, suggesting that Mox1 and Mox2 modulate activation by Mox4 in a heme-dependent fashion. Mutations in a putative repression domain in Mox4 caused constitutive expression of the DAN/TIR genes, indicating a role for this domain in heme repression. MOX4 expression is induced both in anaerobic and cold-shocked cells, so heme may also regulate DAN/TIR expression through inhibition of expression of MOX4. Indeed, ectopic expression of MOX4 in aerobic cells resulted in partially constitutive expression of DAN1. Heme also regulates expression of some of the DAN/TIR genes through the Rox7 repressor, which also controls expression of the hypoxic gene ANB1. In addition Rox1, another heme-responsive repressor, and the global repressors Tup1 and Ssn6 are also required for full aerobic repression of these genes.

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Comparative Analysis of Genetic Determinants Encoding Cadmium, Arsenic, and Benzalkonium Chloride Resistance in Listeria monocytogenes of Human, Food, and Environmental Origin

Frontiers in Microbiology ◽

10.3389/fmicb.2020.599882 ◽

2021 ◽

Vol 11 ◽

Author(s):

Tereza Gelbicova ◽

Martina Florianova ◽

Lucie Hluchanova ◽

Alžběta Kalova ◽

Kristýna Korena ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Benzalkonium Chloride ◽

Extensive Study ◽

Whole Genome Sequencing Data ◽

Production Environment ◽

Sequencing Data ◽

Genetic Determinants ◽

Cadmium Resistance ◽

Chloride Resistance ◽

Genes Encoding

Environmental adaptation of Listeria monocytogenes is a complex process involving various mechanisms that can contribute to their survival in the environment, further spreading throughout the food chain and the development of listeriosis. The aim of this study was to analyze whole-genome sequencing data in a set of 270 strains of L. monocytogenes derived from human listeriosis cases and food and environmental sources in order to compare the prevalence and type of genetic determinants encoding cadmium, arsenic, and benzalkonium chloride resistance. Most of the detected genes of cadmium (27.8%), arsenic (15.6%), and benzalkonium chloride (7.0%) resistance were located on mobile genetic elements, even in phylogenetically distant lineages I and II, which indicates the possibility of their horizontal spread. Although no differences were found in the prevalence of these genes between human and food strains, they have been detected sporadically in strains from the environment. Regarding cadmium resistance genes, cadA1C1_Tn5422 predominated, especially in clonal complexes (CCs) 121, 8, and 3 strains. At the same time, qacH_Tn6188-encoding benzalkonium chloride resistance was most frequently detected in the genome of CC121 strains. Genes encoding arsenic resistance were detected mainly in strains CC2 (located on the chromosomal island LGI2) and CC9 (carried on Tn554). The results indicated a relationship between the spread of genes encoding resistance to cadmium, arsenic, and benzalkonium chloride in certain serotypes and CCs and showed the need for a more extensive study of L. monocytogenes strains to better understand their ability to adapt to the food production environment.

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The usual anaerobic bacterial suspects extracted from a global metagenomic database of Covid19 patients from Peru, Cambodia, China, Brazil and the US - Prevotella, Veillonella, Capnocytophaga, Fusobacterium, Oribacterium and Bacteroides should be monitored for colonization

10.31219/osf.io/dh8f4 ◽

2020 ◽

Author(s):

Sandeep Chakraborty

Keyword(s):

Anaerobic Bacteria ◽

Anaerobic Respiration ◽

Clinical Results ◽

Cellular Level ◽

Heme Binding ◽

Sequencing Data ◽

The Us ◽

Hemoglobin Degradation ◽

Mitochondrial Cytochrome Oxidase ◽

Different Parts

The Covid19 pandemic [1], triggered by novel strain of a coronavirus SARS-Cov2 [2] has spread globally like a wildfire [3] after being first detected in Wuhan.Previous studies from China, Brazil and the US:Previously, several sequencing datasets - some of them published [4–9], others having sequencing data sub- mitted in NCBI (with no associated publications) [10–13] - have revealed the metagenome in these patients from different parts of the world. The overwhelming presence of anaerobic bacteria (very low concentration of oxygen kills them) in these patients has led to the theory that antibiotics (like doxycycline/Metronidazole) targeting these specific organisms may provide better clinical results [14].Two more studies added - patients from Peru and Cambodia:Here, two more studies from Peru (Table 1) and Cambodia (Table 2) provide further corroboration to the anaerobic bacteria theory. These anaerobic bacteria have virtually colonized the metagenome - pushing other aerobic species out of the niche, disrupting the homeostasis. Around 30% and 23% of the reads from Peru and Cambodia are bacterial, respectively. This is not observed in other patients, even when having chronic issues [15].Common opportunistic anaerobic bacteria in this global metagenomic Covid19 datasetHere, I enumerate common opportunistic anaerobic bacteria present in this global metagenomic Covid19 dataset (Table 3). Any or multiple of these might become the main colonizer after SARS-Cov2 infection in Covid19. The trigger of such an event is still elusive. However, once this happens, some of these bacte- ria express hemoglobin degrading proteins [16], heme-binding proteins sequestering heme after hemoglobin degradation [17], ‘plundering‘ iron, and thereby sequestering oxygen [18]. Hypoxia could also result from formate, the by-product of anaerobic respiration, which inhibits mitochondrial cytochrome oxidase, causing hypoxia at the cellular level [19].

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Fluorescence-Based Reporter for Gauging Cyclic Di-GMP Levels in Pseudomonas aeruginosa

Applied and Environmental Microbiology ◽

10.1128/aem.00414-12 ◽

2012 ◽

Vol 78 (15) ◽

pp. 5060-5069 ◽

Cited By ~ 124

Author(s):

Morten T. Rybtke ◽

Bradley R. Borlee ◽

Keiji Murakami ◽

Yasuhiko Irie ◽

Morten Hentzer ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Fluorescent Protein ◽

Subsequent Development ◽

Cellular Level ◽

Host Immune System ◽

Chronic Infections ◽

Content Type ◽

Genes Encoding ◽

Green Fluorescent

ABSTRACTThe increased tolerance toward the host immune system and antibiotics displayed by biofilm-formingPseudomonas aeruginosaand other bacteria in chronic infections such as cystic fibrosis bronchopneumonia is of major concern. Targeting of biofilm formation is believed to be a key aspect in the development of novel antipathogenic drugs that can augment the effect of classic antibiotics by decreasing antimicrobial tolerance. The second messenger cyclic di-GMP is a positive regulator of biofilm formation, and cyclic di-GMP signaling is now regarded as a potential target for the development of antipathogenic compounds. Here we describe the development of fluorescent monitors that can gauge the cellular level of cyclic di-GMP inP. aeruginosa. We have created cyclic di-GMP level reporters by transcriptionally fusing the cyclic di-GMP-responsivecdrApromoter to genes encoding green fluorescent protein. We show that the reporter constructs give a fluorescent readout of the intracellular level of cyclic di-GMP inP. aeruginosastrains with different levels of cyclic di-GMP. Furthermore, we show that the reporters are able to detect increased turnover of cyclic di-GMP mediated by treatment ofP. aeruginosawith the phosphodiesterase inducer nitric oxide. Considering that biofilm formation is a necessity for the subsequent development of a chronic infection and therefore a pathogenicity trait, the reporters display a significant potential for use in the identification of novel antipathogenic compounds targeting cyclic di-GMP signaling, as well as for use in research aiming at understanding the biofilm biology ofP. aeruginosa.

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Hypertrophic cardiomyopathy: genetics

ESC CardioMed ◽

10.1093/med/9780198784906.003.0350 ◽

2018 ◽

pp. 1443-1450

Author(s):

Mohammed Majid Akhtar ◽

Luis Rocha Lopes

Keyword(s):

Genetic Testing ◽

Hypertrophic Cardiomyopathy ◽

Mapk Pathway ◽

Glycogen Storage ◽

Cellular Level ◽

Causative Mutation ◽

Clinical Role ◽

Genes Encoding ◽

Associated Proteins

Hypertrophic cardiomyopathy is most commonly transmitted as an autosomal dominant trait, caused by mutations in genes encoding cardiac sarcomere and associated proteins. Knowledge of the genetic pathophysiology of the disease has advanced significantly since the initial identification of a point mutation in the beta-myosin heavy chain (MYH7) gene in 1990. Other genetic causes of the disease include mutations in genes coding for proteins implicated in calcium handling or which form part of the cytoskeleton. The recent emergence of next-generation sequencing allows quicker and less expensive identification of causative mutations. However, a causative mutation is not identified in up to 50% of probands. At present, the primary clinical role of genetic testing in hypertrophic cardiomyopathy is in the context of familial screening, allowing the identification of those at risk of developing the condition. Genetic testing can also be used to exclude genocopies, particularly in the presence of certain diagnostic ‘red flag’ features, where lysosomal, glycogen storage, neuromuscular or Ras-MAPK pathway disorders may be suspected. The role of individual mutations in predicting prognosis is limited at present. However, the higher incidence of sudden cardiac death in the presence of a family history of such, suggests that genetics play a significant role in determining outcome. With an increased understanding of the impact of these mutations on a cellular level and on longer-term clinical outcomes, the aim in future for gene and mutation specific prognosis or potential disease-modifying therapy is closer.

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Transcriptional regulation of stilbene synthases in grapevine germplasm differentially susceptible to downy mildew

BMC Plant Biology ◽

10.1186/s12870-019-2014-5 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 5

Author(s):

Mario Ciaffi ◽

Anna Rita Paolacci ◽

Marco Paolocci ◽

Enrica Alicandri ◽

Valentina Bigini ◽

...

Keyword(s):

Transcriptional Regulation ◽

Downy Mildew ◽

Transcriptional Activation ◽

Constitutive Expression ◽

Stilbene Synthase ◽

Disease Symptoms ◽

Adaptive Resistance ◽

Genes Encoding ◽

The Impact ◽

Stilbene Biosynthesis

Abstract Background To limit the impact of the downy mildew disease of grapevine and reduce the need to recur to chemical treatments, an effective strategy might be recovering adaptive resistance traits in both cultivated and wild V. vinifera germplasm. Considering that stilbenes represent the most important class of phytoalexins in the Vitaceae, the constitutive expression and transcriptional activation of all the functional members of the stilbene synthase gene family were analysed in a group of nine grapevine genotypes following artificial infection with the oomycete Plasmopara viticola, the causal agent of the disease. In addition, in the same genotypes we analyzed the expression of genes encoding for two transcription factors involved in the transcriptional regulation of the stilbene synthase genes, namely VvMYB14 and VvMYB15, and of genes encoding for chalcone synthases. Results Downy mildew incidence and severity ranged from nihil to high in the grapevine genotypes considered, being low to moderate in a subgroup of V. vinifera genotypes. The constitutive expression of the stilbene synthase genes as well as the extent of their transcriptional activation following P. viticola inoculation appeared to be inversely related to the proneness to develop disease symptoms upon infection. In a specular manner, following P. viticola inoculation all the chalcone synthase genes were up-regulated in the susceptible grapevine genotypes and down-regulated in the resistant ones. The infection brought by P. viticola appeared to elicit a co-ordinated and sequential transcriptional activation of distinct stilbene synthase genes subsets, each of which may be regulated by a distinct and specific MYB transcription factor. Conclusions The present results suggest that the induction of stilbene biosynthesis may contribute to the basal immunity against the downy mildew of grapevine, thus representing an adaptive resistance trait to recover, in both cultivated and wild V. vinifera germplasm. During the early stages of P. viticola infection, an antagonistic interaction between flavonol and stilbene biosynthesis might occur, whose outcome might determine the subsequent extent of disease symptoms. Further studies are needed to decipher the possible regulatory mechanisms involved in the antagonistic crosstalk between these two metabolic pathways in resistant and susceptible genotypes in response to P. viticola.

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The endemic and endangered Maugean Skate (Zearaja maugeana) exhibits short-term severe hypoxia tolerance

Conservation Physiology ◽

10.1093/conphys/coz105 ◽

2020 ◽

Vol 8 (1) ◽

Cited By ~ 1

Author(s):

Andrea J Morash ◽

Jeremy M Lyle ◽

Suzanne Currie ◽

Justin D Bell ◽

Kilian M Stehfest ◽

...

Keyword(s):

Environmental Variability ◽

Cellular Stress Response ◽

Hypoxia Tolerance ◽

Conservation Strategies ◽

Low Oxygen ◽

Short Term ◽

Environmental Challenges ◽

Preferred Habitat ◽

Short Term Exposure ◽

Dissolved O2

Abstract The endangered and range-restricted Maugean skate (Zearaja maugeana) is subjected to large environmental variability coupled with anthropogenic stressors in its endemic habitat, Macquarie Harbour, Tasmania. However, little is known about the basic biology/physiology of this skate, or how it may respond to future environmental challenges predicted from climate change and/or increases in human activities such as aquaculture. These skate live at a preferred depth of 5–15 m where the dissolved oxygen (DO) levels are moderate (~55% air saturation), but can be found in areas of the Harbour where DO can range from 100% saturation to anoxia. Given that the water at their preferred depth is already hypoxic, we sought to investigate their response to further decreases in DO that may arise from potential increases in anthropogenic stress. We measured oxygen consumption, haematological parameters, tissue–enzyme capacity and heat shock protein (HSP) levels in skate exposed to 55% dissolved O2 saturation (control) and 20% dissolved O2 saturation (hypoxic) for 48 h. We conclude that the Maugean skate appears to be an oxyconformer, with a decrease in the rate of O2 consumption with increasing hypoxia. Increases in blood glucose and lactate at 20% O2 suggest that skate are relying more on anaerobic metabolism to tolerate periods of very low oxygen. Despite these metabolic shifts, there was no difference in HSP70 levels between groups, suggesting this short-term exposure did not elicit a cellular stress response. The metabolic state of the skate suggests that low oxygen stress for longer periods of time (i.e. >48 h) may not be tolerable and could potentially result in loss of habitat or shifts in their preferred habitat. Given its endemic distribution and limited life-history information, it will be critical to understand its tolerance to environmental challenges to create robust conservation strategies.

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