Sensitivity of pigmented mucosa and skin to freezing injury.

Pigmented areas of canine skin and oral mucosa were subjected to freezing in situ at various temperatures for the purpose of investigating possible differences in the sensitivity of epidermal cells to cold injury. Destruction of melanocytes occurred in the range of ?4 to ?7 °C, while squamous cells resisted injury even at ?20 °C. Replacement of the lost pigmented cells occurred from the normal tissue at the periphery of the injured area. The experiments suggest that selective destruction of pigmented lesions in clinical conditions may be achieved by freezing tissue to ?4 to ?7 °C or colder, but not to exceed ?20 °C in order to avoid destruction of squamous cells. The experiments also support wider use of cryosurgery for pigmented lesions of the skin and oral cavity.     

Coevolution of dispersal in a parasitoid–host system

Interspecific interactions and the evolution of dispersal are both of interest when considering the potential impact of habitat fragmentation on community ecology, but the interaction between these processes is not well studied. We address this by considering the coevolution of dispersal strategies in a host–parasitoid system. An individual-based host–parasitoid metapopulation model was constructed for a patchy environment, allowing for evolution in dispersal rates of both species. Highly rarefied environments with few suitable patches selected against dispersal in both species, as did relatively static environments. Provided that parasitoids persist, all the variables studied led to stable equilibria in dispersal rates for both species. There was a tendency toward higher dispersal rates in parasitoids because of the asymmetric relationships of the two species to the patches: vacant patches are most valuable for hosts, but unsuitable for parasitoids, which require an established host population to reproduce. High host dispersal rate was favoured by high host population growth rate, and in the parasitoid by high growth rates in both species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Stability and invariant manifolds of a generalized Beddington host-parasitoid model

We will investigate the stability and invariant manifolds of a new discrete host-parasitoid model. It is a generalization of the Beddington–Nicholson–Bailey model. Our study establishes analytically, for the first time, the stability of the coexistence fixed point.     

Recombinant expression,purification, and characterization of polyphenol oxidase 2 (VvPPO2) from “Shine Muscat” (Vitis labruscana Bailey × Vitis vinifera L.)

Polyphenol oxidases (PPOs) catalyze browning reactions in various plant organs, therefore controlling the reactions is important for the food industry. PPOs have been assumed to be involved in skin browning of white grape cultivars; however, the molecular mechanism underlying PPO-mediated browning process remains elusive. We have recently identified a new PPO gene named VvPPO2 from “Shine Muscat” (Vitis labruscana Bailey × V. vinifera L.), and have shown that the gene is transcribed at a higher level than the previously identified VvPPO1 in browning, physiologically disordered berry skins at the maturation stage. In this study, we expressed VvPPO2 in Escherichia coli and, using the purified preparation, revealed unique physicochemical characteristics of the enzyme. Our study opens up a way to not only understand the berry skin browning process but also to elucidate the enzymatic maturation process of grape PPOs.     

中国的肉座菌科V. 肉棒菌属

所有保存于HMAS、HKAS和 HMIGD的采自中国的肉棒菌属Podostroma标本被重新研究,鉴定出肉棒菌P. alutaceum和粗肉棒菌P. grossum两个种,并对这两个种重新进行了详细的描述。鹿角状肉棒菌P. cornu-damae由于缺乏可靠的标本仍存有疑问。滇肉棒菌P. yunnanensis被作为粗肉棒菌P. grossum的异名。     

Spatial mechanisms for coexistence of species sharing a common natural enemy

We examine the conditions under which spatial structure can mediate coexistence of apparent competitors. We use a spatially explicit, host-parasitoid metapopulation model incorporating local dynamics of Nicholson-Bailey type and global dispersal. Depending on the model parameters, the resulting system displays a plethora of asynchronous dynamical behaviors for which permanent or transient coexistence is observed. We identify a number of spatially mediated tradeoffs which apparent competitors can utilize and demonstrate that the dynamics of spatial coexistence can typically be understood from consideration of two and three patch systems. The phase relationships of species abundances are different for our model than for some other mechanisms of spatial coexistence. We discuss the implications of our findings relative to issues of community organization and biological conservation.     

Japan Wine,its characteristics and research

ABSTRACT

A new rule stipulates that wine made in Japan from grapes harvested in Japan be labeled as “Japan wine”. The main grape varieties for Japan Wine, Koshu for white wine and Muscat Bailey A for red, are unique to Japan. Koshu is native to Japan and its origin, long unknown, has recently been revealed through DNA analysis. Wine made from this variety suffered from a lack of characteristic aroma, but a recent study has demonstrated its potential for producing wine with a citrus scent. Muscat Bailey A was bred in Japan. Its characteristic sweet aroma has been identified as being due to furaneol. Another characteristic of its wine is that it has a low concentration of proanthocyanidins (condensed tannin), and the reason for this was revealed recently. These and other studies have been conducted in wine companies, universities, and research institutes in Japan and support the development of Japan Wine.

Abbreviations: SSR: simple sequence repeat; SNP: single nucleotide polymorphism; 3MH: 3-mercaptohexan-1-ol; 4-HDMF: 4-hydroxy-2,5-dimethyl-3(2H)-furanone; PCA: principal component analysis     

Transmitting Tissae and Pollen Tube Growth in Sweet Pepper

Fine structural events in the mature stylar transmitting tissue ofsweet pepper (Capsicum frutescens L. var. grossum Bally) have been investigated byelectron microscope with regard to pollen tribe grwoth. The transmitting tissue consists of parenchymatous cells with large intercellular spaces filled with an electron densesubstance. The pollen tubes grow through the intercellular spaces in the intercellular substance. Cells of this tissue are rich in organelles, especially the rough and tubular ER, and numerous lomasomes near the plasma membrane. It is demonstrated that they function as secretory cells. On the other hand, the fact that the transmitting tissue contains many large amyloplastids with several starch grains in the cytoplasm and numerous globular protein bodies in vacuoles, indicates that the transmitting tissue mayhave some nutritive value for the growth of pollen tubes. The results obtained from this observation are in agreement with those of mostspecies reported by other authors and support the conclusion that the transmitting tissue is not a collenchyma tissue and the nature of intercellular substances is essentially same as that of the middle lamella.     

Small Sample Bias and Variance of Lincoln-Petersen and Bailey Estimators

The Lincoln-Petersen and Bailey estimators of an unknown population size were compared in a computer simulation of capture-recapture sampling with replacement from small populations. The Bailey estimator was negatively biased and had smaller variance than the Petersen estimator. The Petersen estimator tended to be positively biased. The Lincoln-Petersen variance estimator tended to be positively biased while the Bailey variance estimator was negatively biased.