Viruses play important roles in biogeochemical nutrient cycles and act as genomic reservoirs in marine and freshwater environments, the understanding of which brought about the so-called 'third age' of virus ecology in aquatic environments. Unfortunately, the third age is in oceanography and limnology and outside the soil world. The main reason why virus ecology in soils has shown less progress is that agronomical and epidemiological interests were the primary motivation of viral studies by soil microbiologists. In this review, past research on viruses in soils is summarized after the introduction of the ecological traits of viruses, which are the effects of viruses on beneficial bacteria and soil-borne plant pathogens, adsorption of viruses to soils, and soil factors affecting viral inactivation and survival in soils. Horizontal gene transfer (transduction) in soils is also reviewed. Second, the abundance of viruses and their roles in biogeochemical nutrient cycles are summarized in aquatic environments. Five to 25% of the carbon fixed by primary producers is estimated to enter into the microbial loop via virus-induced lysis at different trophic levels in aquatic environments. The diversity of virus communities in aquatic environments estimated from analyses of the frequency distribution of capsid sizes and the morphology of virus populations are reviewed, and recent findings on the genomic diversity of viruses and their roles as the greatest genomic reservoirs in aquatic environments follow in the subsequent section. Viral genomics is elucidating the viral diversity and phylogenetic relationships among viruses in different environments. As the soil environment is a more diverse habitat for viruses than aquatic environments, viruses in soils have great potential to play roles comparable in quantity, which are unique in quality, to those in aquatic environments. Therefore, the potentiality and characteristics of viruses in soils are discussed in the final section for future research on virus ecology in soils from the viewpoints of biogeochemistry and genomic diversity. Synecological approaches to viruses in soils may open up a new era of soil virus ecology.

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We aimed to compare the anti-inflammatory activities of six species of Curcuma drugs using adjuvant arthritis model mice. When orally administered 1 day before the injection of adjuvant, the methanol extract of Curcuma phaeocaulis significantly inhibited paw swelling and the serum haptoglobin concentration in adjuvant arthritis mice. Also when orally administered 1 day after the injection of adjuvant, the methanol extract of Curcuma phaeocaulis significantly inhibited paw swelling. Other Curcuma species (Curcuma longa, Curcuma wenyujin, Curcuma kwangsiensis, Curcuma zedoaria and Curcuma aromatica) had no significant inhibitory effects on adjuvant-induced paw swelling. Cyclooxygenase (COX)-2 activity was significantly inhibited by the methanol extract of C. phaeocaulis. Curcuminoids' (curcumin, bis-demethoxycurcumin and demethoxycurcumin) were rich in C. longa, but less in C. phaeocaulis and C. aromatica, not in C. wenyujin, C. kwangsiensis and C. zedoaria, suggesting that curcuminoids' contents do not relate to inhibition of arthritis swelling. Therefore, C. phaeocaulis may be a useful drug among Curcuma species for acute inflammation, and the active constituents of C. phaeocaulis are not curcuminoids.

Heterocapsa circularisquama DNA virus (HcDNAV; previously designated as HcV) is a giant virus (girus) with a ~356-kbp double-stranded DNA (dsDNA) genome. HcDNAV lytically infects the bivalve-killing marine dinoflagellate H. circularisquama, and currently represents the sole DNA virus isolated from dinoflagellates, one of the most abundant protists in marine ecosystems. Its morphological features, genome type, and host range previously suggested that HcDNAV might be a member of the family Phycodnaviridae of Nucleo-Cytoplasmic Large DNA Viruses (NCLDVs), though no supporting sequence data was available. NCLDVs currently include two families found in aquatic environments (Phycodnaviridae, Mimiviridae), one mostly infecting terrestrial animals (Poxviridae), another isolated from fish, amphibians and insects (Iridoviridae), and the last one (Asfarviridae) exclusively represented by the animal pathogen African swine fever virus (ASFV), the agent of a fatal hemorrhagic disease in domestic swine. In this study, we determined the complete sequence of the type B DNA polymerase (PolB) gene of HcDNAV. The viral PolB was transcribed at least from 6 h post inoculation (hpi), suggesting its crucial function for viral replication. Most unexpectedly, the HcDNAV PolB sequence was found to be closely related to the PolB sequence of ASFV. In addition, the amino acid sequence of HcDNAV PolB showed a rare amino acid substitution within a motif containing highly conserved motif: YSDTDS was found in HcDNAV PolB instead of YGDTDS in most dsDNA viruses. Together with the previous observation of ASFV-like sequences in the Sorcerer II Global Ocean Sampling metagenomic datasets, our results further reinforce the ideas that the terrestrial ASFV has its evolutionary origin in marine environments.

The liver plays a central role in lipoprotein metabolism. In particular, very-low density lipoprotein (VLDL) is assembled in the hepatocytes and secreted into the blood circulation. The VLDL is then catabolized to low-density lipoprotein by lipoprotein lipase and hepatic triglyceride lipase. Obese subjects, especially those with visceral fat accumulation, are frequently associated with hyperlipidemia, non-insulin-dependent diabetes mellitus (NIDDM), and hypertension. The mechanism of hyperlipidemia in visceral fat obesity has not yet been elucidated. Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal model of NIDDM, characterized by obesity with visceral fat accumulation, hyperlipidemia, and late-onset insulin resistance. To elucidate the mechanism of hyperlipidemia observed in OLETF rats, we focused on the production of VLDL by the liver and investigated hepatic messenger RNA (mRNA) levels of microsomal triglyceride transfer protein (MTP), acyl-coenzyme A synthetase (ACS), and apolipoprotein B (apo B), which play important roles in VLDL synthesis and secretion. In 6-week-old OLETF rats, in which insulin resistance had not been manifested, visceral fat weight was already higher and portal free fatty acid (FFA) and VLDL-triglyceride levels were elevated compared with the control rats. Hepatic ACS activity and mRNA levels, and MTP mRNA levels were also increased in OLETF rats, whereas apo B mRNA levels were similar; these results suggest that the enhanced expression of both ACS and MTP genes associated with visceral fat accumulation before developing insulin resistance may be involved in the pathogenesis of hyperlipidemia in obese animal models with NIDDM. (HEPATOLOGY 1998;27:557-562.)