A new genus and species of freshwater monostiliferous hoplonemertean (Nemertea, Enopla) from the People's Republic of China

A new genus and species of freshwater monostiliferous hoplonemertean, Limnemertes poyangensis gen. et sp. nov., from Poyang Lake, People's Republic of China, is described and illustrated. The taxon is compared and contrasted with previously described freshwater hoplonemerteans. This is the fourth species of freshwater nemertean to be described from China and the first recorded from Poyang Lake.     

Small scale variation in decay rate within logs one year after felling: Effect of fungal community structure and moisture content

Abstract Fungal species composition, moisture content, percentage weight loss, and instantaneous decay rate (expressed by rate of CO₂ evolution) was assessed for a total of 186 8 cm³ cubes from 10 beech logs which had been decomposing on the forest floor for 14 months. There was considerable within and between branch variation in decay rate and water content. Water content at the time of sampling was not directly correlated with percentage weight loss or instantaneous decay rate, nor was it correlated with position in the log. However, wood occupied by Ascomycotina (other than Nectria ) tended to be drier than that occupied by Basidiomycotina. In particular wood occupied by Xylaria hypoxylon was drier than that occupied by all other species, although wood in which X. hypoxylon was replacing other fungi was wetter than when X. hypoxylon was alone. Variation in percentage weight loss could not be explained in terms of water content and fungal species composition at the time of sampling, but variation in instantaneous decay rate could. Thus, decay rate by Ascomycotina was significantly less ( P < 0.05) than by Basidiomycotina, and rate of CO₂ evolution from wood occupied by X. hypoxylon alone was significantly slower than from wood in which X. hypoxylon was replacing H. fragiforme or Nectria . The latter was partially correlated with water content but whether this is a cause and effect relationship is uncertain.     

Detection of multiple paternity in the Kemp's ridley sea turtle with limited sampling

An important question in sea turtle biology is the number of males that contribute to the fertilization of a clutch of eggs. Previous studies on other sea turtle species have indicated little to no multiple paternity. We conclude here that female Kemp's ridleys, Lepidochelys kempi , are polyandrous. DNA from 26 mother and offspring groups was analysed at three microsatellite loci to identify paternal alleles. Three paternal alleles were observed among 14 of the clutches; four paternal alleles were observed among the offspring of an additional female. A maximum likelihood analysis not only rejects the model of single paternity, but also rejects the model of equal paternal contribution to the clutch. By explicitly addressing the high mutation rate of microsatellite markers, our analysis rejected mutation as the sole cause of multiple paternal alleles.     

Sensitivity to low-dose/low-LET ionizing radiation in mammalian cells harboring mutations in succinate dehydrogenase subunit C is governed by mitochondria-derived reactive oxygen species

It has been hypothesized that ionizing radiation-induced disruptions in mitochondrial O? metabolism lead to persistent heritable increases in steady-state levels of intracellular superoxide (O?(?U+2212)) and hydrogen peroxide (H?O?) that contribute to the biological effects of radiation. Hamster fibroblasts (B9 cells) expressing a mutation in the gene coding for the mitochondrial electron transport chain protein succinate dehydrogenase subunit C (SDHC) demonstrate increases in steady-state levels of O??- and H?O?. When B9 cells were exposed to low-dose/low-LET radiation (5-50 cGy), they displayed significantly increased clonogenic cell killing compared with parental cells. Clones derived from B9 cells overexpressing a wild-type human SDHC (T4, T8) demonstrated significantly increased surviving fractions after exposure to 5-50 cGy relative to B9 vector controls. In addition, pretreatment with polyethylene glycol-conjugated CuZn superoxide dismutase and catalase as well as adenoviral-mediated overexpression of MnSOD and/or mitochondria-targeted catalase resulted in significantly increased survival of B9 cells exposed to 10 cGy ionizing radiation relative to vector controls. Adenoviral-mediated overexpression of either MnSOD or mitochondria-targeted catalase alone was equally as effective as when both were combined. These results show that mammalian cells over expressing mutations in SDHC demonstrate low-dose/low-LET radiation sensitization that is mediated by increased levels of O??- and H?O?. These results also support the hypothesis that mitochondrial O??- and H?O? originating from SDH are capable of playing a role in low-dose ionizing radiation-induced biological responses.     

Aspects of sieve element ultrastructure in Primula obconica

Summary At maturity, the enucleate sieve element of Primula obconica is lined with a parietal layer of cytoplasm consisting of plasmalemma, one or more cisterna-like layers of endoplasmic reticulum, numerous mitochondria and plastids, and a membrane which apparently separates these cytoplasmic components from a large central cavity. The central cavity contains numerous longitudinally oriented slime tubules. We believe these tubules normally form strands which run the length of the cell and traverse consecutive cells through the sieve-plate pores. Developmental aspects are discussed.This research has been supported by NSF Grant GB 3193.     

Evaluation of an anti-inflammatory factor derived from hyperimmunized cows

An anti-inflammatory factor isolated from milk of hyperimmunized cows was analyzed in vitro and in vivo. Macrophages collected from lacteal secretions of a unimmunized nonlactating cow showed increased ability to kill phagocytosed Staphylococcus aureus when incubated with the anti-inflammatory factor. Mice injected intraperitoneally with 10 mg/kg of anti-inflammatory factor demonstrated an increased LD50 to S. aureus when challenged intraperitoneally. Injected mice also demonstrated significantly (P less than 0.05) less mammary inflammation and involution and increased clearance of S. aureus when challenged intramammarily. Quantitative histologic analysis of mammary tissues from mice injected with anti-inflammatory factor demonstrated significantly (P less than 0.05) more lumen, less interalveolar connective tissue, and less leukocytic infiltration compared with control mice. Mammary glands of mice injected with anti-inflammatory factor and challenged with S. aureus also contained fewer colony-forming units than control mice. The product appeared to exert its effect on the nonspecific defense system via modulation of leukocyte function.     

Excitatory glutamate is essential for development and maintenance of the piloneural mechanoreceptor

The piloneural collar in mammalian hairy skin comprises an intricate pattern of circumferential and longitudinal sensory afferents that innervate primary and secondary pelage hairs. The longitudinal afferents tightly associate with terminal Schwann cell processes to form encapsulated lanceolate nerve endings of rapidly adapting mechanoreceptors. The molecular basis for piloneural development, maintenance and function is poorly understood. Here, we show that Nefh-expressing glutamatergic neurons represent a major population of longitudinal and circumferential sensory afferents innervating the piloneural collar. Our findings using a VGLUT2 conditional-null mouse model indicate that glutamate is essential for innervation, patterning and differentiation of NMDAR(+) terminal Schwann cells during piloneural collar development. Similarly, treatment of adult mice with a selective NMDAR antagonist severely perturbed piloneural collar structure and reduced excitability of these mechanosensory neurons. Collectively, these results show that DRG-derived glutamate is essential for the proper development, maintenance and sensory function of the piloneural mechanoreceptor.