Genomic analysis of the smallest giant virus — Feldmannia sp. virus 158

Genomic analysis of Feldmannia sp. virus 158, the second phaeovirus to be sequenced in its entirety, provides further evidence that large double-stranded DNA viruses share similar evolutionary pressures as cellular organisms. Reductive evolution is clearly evident within the phaeoviruses which occurred via several routes: the loss of genes from an ancestral virus core genome most likely through genetic drift; and as a result of relatively large recombination events that caused wholesale loss of genes. The entire genome is 154,641 bp in length and has 150 predicted coding sequences of which 87% have amino acid sequence similarities to other algal virus coding sequences within the family Phycodnaviridae. Significant similarities were found, for thirty eight coding sequences (25%), to genes in gene databanks that are known to be involved in processes that include DNA replication, DNA methylation, signal transduction, viral integration and transposition, and protein-protein interactions. Unsurprisingly, the greatest similarity was observed between the two known viruses that infect Feldmannia, indicating the taxonomic linkage of these two viruses with their hosts. Moreover, comparative analysis of phycodnaviral genomic sequences revealed the smallest set of core genes (10 out of a possible 31) required to make a functional nucleocytoplasmic large dsDNA virus.     

Complete mitochondrial genomes of the three brown algae (Heterokonta: Phaeophyceae) Dictyota dichotoma, Fucus vesiculosus and Desmarestia viridis

We report the complete mitochondrial sequences of three brown algae (Dictyota dichotoma, Fucus vesiculosus and Desmarestia viridis) belonging to three phaeophycean lineages. They have circular mapping organization and contain almost the same set of mitochondrial genes, despite their size differences (31,617, 36,392 and 39,049 bp, respectively). These include the genes for three rRNAs (23S, 16S and 5S), 25–26 tRNAs, 35 known mitochondrial proteins and 3–4 ORFs. This gene set complements two previously studied brown algal mtDNAs, Pylaiella littoralis and Laminaria digitata. Exceptions to the very similar overall organization include the displacement of orfs, tRNA genes and four protein-coding genes found at different locations in the D. dichotoma mitochondrial genome. We present a phylogenetic analysis based on ten concatenated genes (7,479 nucleotides) and 29 taxa. Stramenopiles were always monophyletic with heterotrophic species at the base. Results support both multiple primary and multiple secondary acquisitions of plastids. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. Nucleotide sequence data reported are available in the GenBank databases under the accession numbers AY494079, AY500368 and AY500367.     

PPARs信号通路参与肠道菌群和棕色脂肪组织的代谢调控肥胖

背景:肠道菌群与棕色脂肪组织之间存在着复杂的调控机制和广泛联系,但是目前机制尚未阐明。目的:揭示棕色脂肪组织与肠道菌群间的潜在关系,为接下来的研究提供实验思路。方法:由第一作者应用计算机以“brown adipose tissue,intestinal flora,obesity,peroxisome proliferator activated receptor family”为英文检索词,以“棕色脂肪组织,肠道菌群,肥胖,过氧化物酶体增殖物激活受体家族”为中文检索词在PubMed、万方、维普、知网数据库中检索1994-01-01/2020-06-01的相关文献,并对文献的相关内容进一步筛选、归纳分析与总结,最终纳入38篇相关文献进行综述。结果与结论:①肠道菌群失调会影响过氧化物酶体增殖物激活受体(peroxisome proliferator-activated receptors,PPARs),PPARs又可以影响棕色脂肪组织的代谢进而调控肥胖;PPARα、PPARβ和PPARγ都与脂肪代谢有关,可以被相应的激活剂激活促进棕色脂肪组织的表达,其中PPARγ在肠道菌群和棕色脂肪组织中的联系最为密切,肠道菌群代谢的变化可以上调PPARγ的表达,从而激活棕色脂肪组织达到减肥的目的;②调节肠道菌群与棕色脂肪组织的关系可以治疗肥胖症;③从棕色脂肪组织、PPARs信号通路两者中研究抵抗肥胖的相关药物前景可观。     

Huge juxtacortical brown tumor in two patients with secondary hyper-parathyroidism due to chronic renal failure

The brown tumor of the skeletal system is mainly caused by hyperparathyroidism (HPT), and HPT is divided into three categories according to its causes: primary, secondary and tertiary HPT. The secondary HPT patients with brown tumor caused by chronic renal insufficiency are rarely reported. The tumor occurs mostly in the bones such as metacarpals, phalanges, skull, pelvis, clavicle, ribs, femur and spine. We reported two cases of juxtacortical brown tumor in patients with HPT secondary to chronic renal insufficiency which has never been reported previously.     

Characterization of different viruses infecting the marine harmful algal bloom species Phaeocystis globosa

Twelve lytic viruses (PgV) infecting the marine unicellular eukaryotic harmful algal bloom species Phaeocystis globosa were isolated from the southern North Sea in 2000-2001 and partially characterized. All PgV isolates shared common phenotypic features with other algal viruses belonging to the family Phycodnaviridae and could be categorized in four different groups. Two main groups (PgV Group I and II) were discriminated based on particle size (150 and 100 nm respectively), genome size (466 and 177 kb) and structural protein composition. The lytic cycle showed a latent period of 10 h for PgV Group I and latent periods of 12 h and 16 h for PgV Group IIA and IIB. Host specificity and temperature sensitivity finally defined a fourth group (PgV Group IIC). Our results imply that viral infection plays an important role not only in P. globosa dynamics but also in the diversity of both host and virus community.     

Characterization of a new bunyavirus and its derived small RNAs in the brown citrus aphid,Aphis citricidus

High-throughput sequencing is widely used for virus discovery, and many RNA viruses have been discovered and identified. A new negative-sense single-stranded RNA virus was identified in the brown citrus aphid and named Aphis citricidus bunyavirus. The genome consists of large (7037 nt), medium (3462 nt), and small (1163 nt) segments. Phylogenetic analysis and amino acid sequences identities of this virus with other bunyaviruses suggest that it is a new species belonging to the family Phenuiviridae. The small interfering RNA pathway could be involved against the infection of this virus in brown citrus aphid as supported by the viral derived small RNAs. The discovery of this virus illustrates the diversity of RNA viruses and contributes to the classification of bunyaviruses.

     

Antigenic drift,antigenic shift and interferon antagonists: how bunyaviruses counteract the immune system

Members of the Bunyaviridae family are amongst the most widespread viruses in the world. They can be found on every inhabited continent at virtually every latitude, and are able to infect a wide range of arthropods, plants and mammals including humans. More than 300 named viruses are contained within the family Bunyaviridae (Virus Taxonomy: Seventh Report of the International Committee on Taxonomy of Viruses (2000) 599), and several members cause significant disease in humans or domestic animals. Despite being recognised as an emerging threat, relatively little is known about their virulence mechanisms. Here, we try to summarise the current state of knowledge about how the viruses of the Bunyaviridae succeed in establishing infection in the face of a powerful immune system.     

Waiting in the wings: The potential of mosquito transmitted flaviviruses to emerge

The sudden dramatic emergence of the mosquito transmitted flavivirus Zika virus has bought to the world’s attention a relatively obscure virus that was previously only known to specialist researchers. The genus Flavivirus of the family Flaviviridae contains a number of well-known mosquito transmitted human pathogenic viruses including the dengue, yellow fever, Japanese encephalitis and West Nile viruses. However, the genus also contains a number of lesser known human pathogenic viruses transmitted by mosquitoes including Wesselsbron virus, Ilheus virus, St. Louis encephalitis virus and Usutu virus. This review summarizes our knowledge of these lesser known mosquito transmitted flaviviruses and highlights their potential to emerge.     

Immune modulation during latent herpesvirus infection

Nearly all human beings, by the time they reach adolescence, are infected with multiple herpesviruses. At any given time, this family of viruses accounts for 35-40 billion human infections worldwide, making herpesviruses among the most prevalent pathogens known to exist. Compared to most other viruses, herpesviruses are also unique in that infection lasts the life of the host. Remarkably, despite their prevalence and persistence, little is known about how these viruses interact with their hosts, especially during the clinically asymptomatic phase of infection referred to as latency. This review explores data in human and animal systems that reveal the ability of latent herpesviruses to modulate the immune response to self and environmental antigens. From the perspective of the host, there are both potentially detrimental and surprisingly beneficial effects of this lifelong interaction. The realization that latent herpesvirus infection modulates immune responses in asymptomatic hosts forces us to reconsider what constitutes a 'normal' immune system in a healthy individual.     

The use of degenerate-primed random amplification of polymorphic DNA (DP-RAPD) for strain-typing and inferring the genetic similarity among closely related viruses

Often it is necessary to distinguish among strains of closely related viruses, as well as infer the genetic relatedness within large groups of viruses. Current methods for strain-typing viruses are time-consuming, require significant quantities of extracted DNA, and/or may require a priori genetic information. In this study we modified random amplification of polymorphic DNA (RAPD) by using a degenerate primer to produce unique and reproducible banding patterns from viral genomes. In the degenerate-primed RAPD analysis (DP-RAPD), a selection of algal virus and bacteriophage strains were profiled that encompassed an array of genome sizes and virus families. Closely related viruses (e.g. strains infecting Micromonas pusilla) generated similar, yet unique DP-RAPD patterns that could be readily distinguished from viruses within the same family (Phycodnaviridae) infecting a Chlorella-like alga. As well, marine vibriophage from the families Myoviridae, Siphoviridae, and Podoviridae showed high diversity and were distinct from coliphage and cyanophage. Contamination of host DNA, even at levels above those that would normally be encountered, did not interfere with the viral patterns. These findings describe a rapid, PCR-based tool for strain-typing viral isolates that allows inferences to be made on genetic relatedness within groups of closely related viruses.     

Effect of semi-compulsory alcoholization on brown fat in mice

We studied brown adipose tissue isolated from mice receiving 20% ethanol as a single source of fluid. In vitro O₂ utilization by brown adipose tissue decreased after one month of forced alcohol intake, but surpassed the control after 3 months of ethanol drinking. The absolute and relative weight of brown adipose tissue also increased at this term. The rate of in vivo O₂ utilization also decreased during the first experimental month and returned to normal after 3 months.     

Utilization of interferometric light microscopy for the rapid analysis of virus abundance in a river

There is a constant need for direct counting of biotic nanoparticles such as viruses to unravel river functioning. We used, for the first time in freshwater, a new method based on interferometry differentiating viruses from other particles such as membrane vesicles. In the French Marne River, viruses represented between 42 and 72% of the particles. A spring monitoring in 2014 revealed their increase (2.1 × 10⁷ to 2.1 × 10⁸ mL⁻¹) linked to an increase in algal biomass and diversity of bacterial plankton. Predicted virus size distributions were in agreement with transmission electron microscopy analysis suggesting a dominance of large viruses (≥60 nm).     

A Promising Energetic Polymer from Posidonia oceanica Brown Algae: Synthesis,Characterization, and Kinetic Modeling

In this study, microcrystalline cellulose nitrate (MCCN) as energetic polymer is successfully obtained from Posidonia oceanica brown algae (POBA). Fourier transform infrared spectroscopy (FTIR) results show alterations in the intensities of some absorption bands, suggesting a significant difference in the chemical structure between microcrystalline cellulose and the emergent MCCN samples. X‐ray diffraction (XRD) measurements indicate that MCCNs are more crystalline than conventional nitrocellulose (NC). According to scanning electron microscopy (SEM), both NC and MCCN reveal a compact structure and a rough surface. Differential scanning calorimetry (DSC) displays that the thermal degradation of MCCNs shifts to lower temperatures compared to the respective NCs. Furthermore, in comparison with NC samples, MCCN samples exhibit high density, high nitrogen content, low viscosity‐average molecular weight, and good thermal stability. On the other hand, kinetic modeling based on DSC data is carried out by isoconversional integral methods to determine Arrhenius parameters and the decomposition mechanisms. It is found that MCCNs present lower activation energies than conventional NCs with a decrease of ≈6%. Finally, this work opens a new pathway to prepare MCCN from POBA, and it is expected to have applications in several areas such as propellants, energetic binders, and gas generators.     

Catecholaminergic and peptidergic nerves in naturally occurring and pheochromocytoma-associated human brown adipose tissue

Noradrenergic and peptidergic innervations in naturally occurring and pheochromocytoma-associated human perirenal brown adipose tissue were demonstrated. The presence of both parenchymal and periarterial noradrenergic nerve plexuses was revealed by the sucrose-potassium-glyoxylic-acid (SPG) technique in all tissue samples. Immunohistochemical studies also indicated the presence of neuropeptide Y-like, calcitonin gene-related peptidelike, substance P-like, and bombesinlike immunoreactive nerves in the adventitia of both inter- and intralobular arteries. At a more peripheral level, only neuropeptide Y-like immunoreactive elements were observed in the parenchymal field. No somatostatinlike or enkephalinlike immunoreactivity was detected. The specific distributions of noradrenergic and peptidergic nerves were similar in both naturally occurring and pheochromocytoma-associated brown adipose tissue. Thus these findings indicate a plurality of innervation in human perirenal brown fat.     

Ultrastructure of Brown Tumor of Hyperparathyroidism

The ultrastructure of two cases of brown tumor of hyperparathyroidism is described. The most frequent cells found are multinucleated giant cells and fibroblasts. The giant cells have ultrastructural features similar to osteoclasts such as numerous mitochondria, dilated rough endoplasmic reticulum, and short filopodia. However, the ruffled borders typical of osteoclasts are not seen. In this manner, the giant cells of brown tumor are inactive osteoclasts. The fibroblasts show myofibroblastic differentiation. We think that brown tumor represents a reparative cellular process similar to giant cell reparative granuloma of bone.     

Catecholaminergic innervation of interscapular brown adipose tissue in the naked mole-rat (Heterocephalus glaber)

The thermogenic potential of the interscapular brown fat pad in the naked mole-rat Heterocephalus glaber , that exhibits poikilothermic thermal responses to changing temperatures is reported. Histological and ultrastructural study of the brown fat pad showed that it consists of layers of skeletal muscle interposed between the layers of brown adipose tissue with both unilocular and multilocular adipocytes. Large numbers of mitochondria were present between and around the lipid droplets of these cells. Glyoxylic acid condensation, used to demonstrate catecholaminergic nerves, was evident in low concentrations in the connective tissue between the brown adipocytes. A 3-dimensional computer-aided reconstruction of the fat pad showed the extent and ramification of nerves and blood vessels between the adipocytes. These findings show that although the naked mole-rat is regarded as an endothermic poikilotherm, it possesses anatomical features usually found in homeothermic mammals, which are essential for thermogenesis.     

Molecular epidemiology of European brown hare syndrome virus in France between 1989 and 2003

Summary. Genetic diversity between French European brown hare syndrome (EBHS) viruses since the disease appeared has been evaluated. Nucleotide sequencing of the partial capsid protein genes of 169 EBHS viruses collected from various parts of France between 1989 and 2003, three reference strains, and a Greek EBHSV collected in 2002 revealed a maximum nucleotide divergence of 11.7%, indicating a high level of conservation between viruses. Two major groups were identified. The first group contained EBHS viruses collected since 1989 from different parts of France, the reference strains, and all of the viruses located in the far north of France. In this group, three genogroups were clearly identified as mainly related to their geographic origin. The distribution of the viruses suggests that the early viruses have not disappeared and have slowly evolved in their area of origin. The second group, supported by a significant bootstrap value, contained the Greek EBHSV with the French EBHS viruses collected between 1999 and 2003 from regions of southern France. It constitutes a newly identified genogroup. Our results demonstrate strong differences in genetic evolution between EBHSV and rabbit haemorrhagic disease virus, with persistence of the earlier EBHS viruses and interaction between the geographical and temporal distributions.