Effect of yeast extract on growth kinetics during aerobic biodegradation of chlorobenzoic acids

The Monod or Andrews kinetic parameters describing the growth of Pseudomonas sp. CPE2 strain on 2,5-dich!orobenzoic acid and 2-chlorobenzoic acid, and Al-caligenes sp. CPE3 strain on 3,4-dichlorobenzoic acid, 4-chlorobenzoic acid, and 3-chlorobenzoic acid were determined from batch and continuous growth experiments conducted in the presence or absence of yeast extract (50 mg/L). Strain CPE2 displayed inhibitory growth kinetics in the absence of yeast extract and a noninhibitory kinetics in the presence of yeast extract. Similar results were obtained for CPE3. The presence of yeast extract also resulted in a significant increase in the affinity of the strains for the chlorobenzoic acids they degraded. (c) 1995 John Wiley & Sons, Inc.     

Effects of fungal pretreatment and steam explosion pretreatment on enzymatic saccharification of plant biomass

The effects of consecutive treatments by a lignin-degrading fungus Phanerochaete chrysosporium and by steam explosion for the enzymatic saccharification of plant biomass were studied experimentally, and the optimal operational conditions for obtaining the maximum saccharification were evaluated. Beech wood-meal was treated by the fungus for 98 days and then by high steam temperatures of 170-230 degrees C with steaming times of 0-10 min. The treatment of the wood-meal by fungus prior to steam explosion enhanced the saccharification of wood-meal. The treated wood-meal was separated into holo-cellulose, water soluble material, methanol soluble lignin, and Klason lignin. The saccharification decreased linearly with the increase in the amount of Klason lignin. It was estimated by the equation for the saccharification of exploded wood-meal expressed as a function of steam temperature and steaming time that the maximum saccharification of wood-meal was obtained by consecutive treatments such as fungal treatment for 28 days and then steam explosion at a steam temperature of 215 degrees C and a steaming time of 6.5 min. (c) 1995 John Wiley & Sons, Inc.     

Antibiosis and antixenosis of chrysanthemum cultivars to the aphidAphis gossypii

An assessment was made of the antibiotic and antixenotic resistance of three cultivars of autumn flowering chrysanthemum (derived fromDendranthema morifolium (Ramat) Tzvelev andD. indicum (L.) Desmoulins) to the aphidAphis gossypii Glover. Antibiosis was also assessed at the top, middle and lower leaves of the plant. The three cultivars showed a range of resistance with Hero being the most susceptible, Surfine the most resistant and Purple Anne intermediate. There was a trend for antibiosis to improve with position down the plant, however there were cultivar by position interactions. Antixenosis was assessed at two levels, the first being under conditions where the aphid had complete access to the plant in caged choice assays and the second being under conditions where the aphid only had host odour to assess under olfactometer choice conditions. Preferences under the caged choice conditions found Hero to be the most preferred cultivar while there was no preference shown between Purple Anne and Surfine. However, olfactometer assessments showed Hero to be the least preferred of the three cultivars and, again, no preferences could be found between Purple Anne and Surfine.     

Host relationships ofDasineura ingeris: oviposition preferences and juvenile survival on clones ofSalix viminalis, otherSalix species and hybrids

In the present study we assessed the extent to which oviposition preferences and larval survival rates of the gall midge Dasineura ingeris Sylvén & Lövgren (Diptera: Cecidomyiidae) can explain variation in its use of Salix viminalis phenotypes as hosts. Furthermore, based on oviposition preferences and juvenile survival rates we estimated the host potential of various Salix species and species hybrids. Egg distribution patterns explained 67% of the intraspecific variation in damage to S. viminalis shoots in the field. Juvenile survival, on the other hand, was not related to field damage or egg distribution patterns among the S. viminalis clones studied. Clones of complete or partial S. viminalis origin ranked highest in suitability for D. ingeris survival, and four out of these six clones also received the highest egg rankings. Species belonging to the subgenus Salix were not oviposited on at all, whereas others belonging to the same subgenus as S. viminalis, i.e. Vetrix, were intermediate in terms of oviposition rates. Although there was a significant correlation between D. ingeris egg distributions and larval survival rates on the clones in the Salix species/hybrid set, mismatches were evident.     

粤北大东山种子植物区系研究

大东山位于广东北部,地理位置约为２４°５０′～２５°００′Ｎ,１１２°３７′～１１２°４７′Ｅ。大东山有种子植物１６１科,５６０属,１１２４种。其中裸子植物６科,１０属,１４种;被子植物１５５科,５５０属,１１１０种。大东山区系的表征科是蔷薇科、樟科、茶科、壳斗科、山矾科、冬青科、木兰科、安息香科和金缕梅科。属的地理成分组成为热带分布属占５４．３４％,温带分布属占４５．６６％。本区系与江西九连山及福建武夷山区系有密切的联系,与黑石顶、大瑶山和花坪区系的联系也较紧密。大东山区系属华南地区的一部分。     

Tolerance to the fungal pathogen Rhizoctonia solani AG4 of transgenic tobacco expressing the maize ribosome-inactivating protein b-32

The maize b-32 protein is a functional ribosome-inactivating protein (RIP), inhibiting in vitro translation in the cell-free reticulocyte-derived system and having specific N-glycosidase activity on 28S rRNA. Previous results indicated that opaque-2 (o2) mutant kernels, lacking b-32, show an increased susceptibility to fungal attack and insect feeding and that ectopic expression in plants of a barley and a pokeweed RIP leads to increased tolerance to fungal and viral infection. This prompted us to test whether b-32 might functi on as a protectant against pathogens. The b32.66 cDNA clone under the control of the potato wun1 gene promoter was introduced into tobacco by Agrobacterium tumefaciens-mediated transformation. Out of 23 kanamycin resistant regenerated shoots, 16 contained a PCR fragment of the corrrect size spanning the boundary between the promoter used and the coding region of the b-32 gene. Eight independently transformed tobacco lines were randomly chosen for protein analysis: all of them expressed b-32 protein. The data presented indicate that transgenic tobacco plants expressing b-32 show an increased tolerance against infection by the soil-borne fungal pathogen Rhizoctonia solani Kuhn     

中缝核提取液对体外培养的中脑黑质神经元存活和生长的影响

中脑黑质是中缝核５－ＨＴ神经元最早期的靶组织之一。为了分析神经元对其靶细胞的作用是受某种特异性蛋白或神经营养因子的影响,本文用中缝核提取液作用于体外培养的中脑黑质神经元,证明了该提取液能促进中脑黑质神经元的存活和生长,其活性部分是分子量大于３０ｋＤ的组份,经ＳＤＳ－聚丙烯酰胺梯度凝胶电泳,呈现一条主带,分子量在４３ｋＤ左右。     

Enhanced plant regeneration in grain and sweet sorghum by asparagine,proline and cefotaxime

Summary Cefotaxime ( 50 and 100 mg/1 ), a cephalosporin antibiotic and the amino acids asparagine and proline (200 mg/l) enhanced the production of embryogenic callus, increased the frequency of plant regeneration, and delayed the loss of regeneration potential in immature embryo-derived callus cultures ofSorghum bicolor (L.) Moench. Although these compounds did not promote callus induction or growth of callus, they influenced plant regeneration considerably in 10 low responding genotypes of grain and high anthocyanin containing sweet sorghums.     

Regeneration of whole plants from protoplasts isolated from tissue-cultured shoot primordia of garlic (Allium sativum L.)

Protoplasts derived from tissue-cultured shoot primordia of garlic (Allium sativum L.) initiated successive cell divisions within 4 days and formed small individual calli (0.2mm in diameter) after 5 weeks of culture on Gamborg's B5 medium supplemented with 0.1% casein hydrolysate, 1mg/1 1-naphthaleneacetic acid and 1mg/1 6-benzylaminopurine. Plating efficiency was roughly 5% at the density of 1x10⁴ protoplasts/ml of medium. Adventitious buds developed from the calli during subsequent subculture on Gamborg's B5 medium supplemented with 40mg/l adenine and 10% coconut milk. When transferred to the same medium without supplements, these buds grew into shoots and rooted. The regenerated garlic plantlets were successfully transferred to the greenhouse and grew into whole plants.