The Ecological Distribution of Tardigrades in Newfoundland

The ecological distribution of tardigrades on the island of Newfoundland, Canada is greatly affected by both abiotic and biotic factors. Altitude and type of bedrock are major determining factors in tardigrade distribution while both moisture content of the environment and rate of dessication of the mosses and lichens in which they live appear to be other factors contributing to their distribution. A number of cases of apparent competitive exclusion and inter-specific competition have been noted which probably also affect tardigrade distribution.     

中国东部武夷山风景区苔藓中的缓步动物

记述了采自中国东部福建省武夷山风景区苔藓中的缓步动物11种,包括:日本棘影熊虫Echiniscus japonicus Morikawa,1951中国东部新纪录种;结痂棘影熊虫Echiniscus scabrospinesus Fontoura,1982中国东部新纪录种;华美假棘影熊虫Pseudechiniscus facettalis Petersen,1951中国东部新纪录种;迟缓小斑熊虫Milnesium tardigradum(Doyère,1840);埃卡门大生熊虫Macrobiotus ariekammensis Weglarska,1965中国东部新纪录种;节值大生熊虫,模式亚种Macrobiotus harms worthi harmsworthi Murray,1907;华丽大生熊虫Macrobiotus richtersi Murray,1911;陆栖大生熊虫Macrobiotus terricola Miheli,1949;异常拉玛熊虫Ramazzottius anomalus(Ramazzotti,1962)中国新纪录种;肥曲拉玛熊虫Ramazzottius oberhaeuseri(Doyère,1840);黄色具矛熊虫Doryphoribius flavus(Iharos,1966)中国东部新纪录种。所有的标本均保存于中国科学院水生生物研究所。     

Crystal structure of secretory abundant heat soluble protein 4 from one of the toughest “water bears” micro‐animals Ramazzottius Varieornatus

Though anhydrobiotic tardigrades (micro‐animals also known as water bears) possess many genes of secretory abundant heat soluble (SAHS) proteins unique to Tardigrada, their functions are unknown. A previous crystallographic study revealed that a SAHS protein (RvSAHS1) from one of the toughest tardigrades, Ramazzottius varieornatus, has a β‐barrel architecture similar to fatty acid binding proteins (FABPs) and two putative ligand binding sites (LBS1 and LBS2) where fatty acids can bind. However, some SAHS proteins such as RvSAHS4 have different sets of amino acid residues at LBS1 and LBS2, implying that they prefer other ligands and have different functions. Here RvSAHS4 was crystallized and analyzed under a condition similar to that for RvSAHS1. There was no electron density corresponding to a fatty acid at LBS1 of RvSAHS4, where a putative fatty acid was observed in RvSAHS1. Instead, LBS2 of RvSAHS4, which was composed of uncharged residues, captured a putative polyethylene glycol molecule. These results suggest that RvSAHS4 mainly uses LBS2 for the binding of uncharged molecules.     

中国神农架国家森林公园苔藓中的缓步动物

记述了采自湖北省西部神农架国家森林公园苔藓中的缓步动物12种,包括:日本棘影熊虫Echiniscus japonicus Morikawa,1951;双粒棘影熊虫Echiniscus bigranulatus Richters,1907中国新纪录种;华美假棘影熊虫Pseudechiniscus facettalis Petersen,1951;于猪假棘影熊虫Pseudechiniscus suillus(Ehrenberg,1853);迟缓小斑熊虫Milnesium tardigradum(Doyère,1840);隐匿大生熊虫Macrobiotus adelges Dastych,1977;锦葵大生熊虫Macrobiotus hibiscus Barros,1942中国新纪录种;胡芬大生熊虫Macrobiotus hufelandi Schultze,1833;华丽大生熊虫Macrobiotus richtersi Murray,1911;陆栖大生熊虫Macrobiotus terricola Mihel(c)I(c),1949;水生趾生熊虫Dactylobiotus aquatilis Yang,1999;金猴等高熊虫Isohypsibius jinhouensis sp. Nov..所有的标本均保存于中国科学院水生生物研究所.     

Seasonal and Altitudinal Variation in the Distribution and Abundance of Tardigrada on Dugger Mountain, Alabama

A seasonal survey of the distribution of terrestrial tardigrades on Dugger Mountain, Alabama, was conducted during the time period from April 1997 through April 1998. Cryptogams from five trees (Quercus alba), three on north-facing slopes and two on south-facing slopes, were sampled seasonally at three stations (645 m, 410 m, 183 m) along an unnamed tributary of the South Fork of Terrapin Creek. Trees were chosen based on their location outside the riparian zone. Tardigrades were extracted from the samples, mounted individually in Hoyer's medium, and identified to species with phase microscopy. Seasonal and altitudinal variations in the distribution of the populations on the north- and south-facing slopes were determined. Present on Dugger Mountain were tardigrades belonging to 12 species (Macrobiotus cf. areolatus/tonollii, Macrobiotus cf. echinogenitus, Macrobiotus islandicus, Macrobiotus richtersi, Minibiotus intermedius, Milnesium tardigradum, Diphascon pingue, Hypsibius pallidus, Echiniscus cf. arctomys, Echiniscus virginicus, Pseudechiniscus ramazzottii, and Pseudechiniscus suillus). Due to the small numbers of individuals of each species, the total numbers of tardigrades of all species were pooled. There were no significant differences in the mean number of species or the mean number of all tardigrades per sample at each station (altitude). However, seasonal differences in both abundance and number of species were detected in pooled samples due to the high numbers collected in spring 1997.     

Protecting activity of desiccated enzymes

Protein‐based biological drugs and many industrial enzymes are unstable, making them prohibitively expensive. Some can be stabilized by formulation with excipients, but most still require low temperature storage. In search of new, more robust excipients, we turned to the tardigrade, a microscopic animal that synthesizes cytosolic abundant heat soluble (CAHS) proteins to protect its cellular components during desiccation. We find that CAHS proteins protect the test enzymes lactate dehydrogenase and lipoprotein lipase against desiccation‐, freezing‐, and lyophilization‐induced deactivation. Our data also show that a variety of globular and disordered protein controls, with no known link to desiccation tolerance, protect our test enzymes. Protection of lactate dehydrogenase correlates, albeit imperfectly, with the charge density of the protein additive, suggesting an approach to tune protection by modifying charge. Our results support the potential use of CAHS proteins as stabilizing excipients in formulations and suggest that other proteins may have similar potential.     

Ovarian Structure in Milnesium tardigradum (Tardigrada, Milnesiidae) during Early Vitellogenesis

The ultrastructure of the ovary of Milnesium tardigradum during early vitellogenesis is described. Within the ovary, there were large multinuclear cells surrounded by many mononuclear oocytes. Observation of serial sections revealed four multinuclear cells that were connected to each other by cytoplasmic bridges. Each peripheral oocyte was connected to the multinuclear cell. An enormous ER-like structure was conspicuous in the centre of the multinuclear cell. The presence of large numbers of lipid droplets and yolk granules in both multinuclear cells and many mononuclear oocytes suggested a role as nurse cells. A small number of these oocytes grow to be eggs. The structural features of the multinuclear nurse cell were compared with other known examples.