Extracellular enzymes of some additional fungi associated with mushroom culture

Twenty-four fungus isolates from the compost utilized in commercially growing Agaricus brunnescens were tested for their ability to produce extracellular enzymes involved in the degradation of cellulose, lignin and xylan, the major components of the straw of the compost. All 24 isolates were able to degrade carboxymethyl cellulose. Most were classified as weak or moderate producers of exo--glucanase. Twenty of the 24 were also able to hydrolyze filter paper, a crystalline cellulose. Nineteen of the 24 were able to hydrolyze xylan, a hemicellulose. The production of extracellular polyphenol oxidases was detected utilizing two tests; the blueing of alcoholic gum guaiacol, which indicates tyrosinase production, and the browning of malt extract-gallic acid agar, which indicates laccase production. Twenty produced tyrosinase, but only eight produced laccase. Agaricus brunnescens was also included in all of the tests. It produced exo--glucanase, hemicellulase, tyrosinase and lactase.     

Cellulolytic enzymes of fungi isolated from wood materials

Species of Cunninghamella, Gliocladium deliquescens, Trichoderma harzianum and T. koningii were isolated from rotten wood chips. When grown on medium containing cellulose, all except Cunninghamella produced the three primary enzymes (exoglucanase, endoglucanase and -glucosidase) of the cellulase complex. The patterns for enzyme production, changes in mycelial mass and pH of the induction medium for T. harzianum and T. koningii were closely similar, and were distinguishable from those of G. deliquescens.     

Social behavior of captive,group-living Orangutans

The behavior of orang-utans (Pongo pygmaeus)was observed in two captive groups (one adult group, one juvenile group). Activity profiles,animal interactions, and compartmental spatial use for both adult-group and juvenile-group individuals were recorded over a 9-month period. Behavioral repertoires for both groups included large amounts of social activity. Equivalent amounts of social activity were found for each group. The social behavior of juvenile animals involved more active behavior such as play. The social behavior of the adult animals was more subtle, involving social monitoring and allogrooming. These results indicate that orangutans, at least when group-living in captivity, exhibit the potential to display social behavior which is apparently of greater frequency and complexity than that which has been observed in the wild. These findings suggest that the solitary behavior of wild orangutans is not a necessary characteristic of orangutan behavior. Under different environmental conditions orangutans appear to readily adapt socially, and, like other nonhuman primates,they have the capacity to exhibit complex and subtle social behavior. This report is based on part of a senior thesis submitted by Sara D. Edwards     

聚多巴胺改性聚合物在神经修复中的研究进展 *

多巴胺在碱性条件下会发生自聚合生成聚多巴胺。由于聚多巴胺具有超强黏附性能,在过去几年中其被大量应用于修饰各类生物材料。神经修复中使用的材料多为聚合物,但单独使用聚合物修复神经的效果不佳。聚多巴胺改性聚合物的亲水性和生物相容性均优于单一聚合物。除此以外,聚合物上的聚多巴胺涂层还可用于进一步修饰促进神经修复的分子。综述了聚多巴胺的合成机理、性能以及聚多巴胺改性各类聚合物在神经修复中的研究进展,并展望了该类材料的发展前景。     

Polyamines and protein synthesis: Studies in various polyamine-requiring mutants ofEscherichia coli

Summary DifferentEscherichia coli mutants auxotrophic for polyamines were studied in order to investigate the relationships among polypeptide synthesis in cell-free systems, ribosomal distribution profiles and endogenous polyamine pools. Thein vitro protein synthetic activity and the polyribosomal content were reduced in extracts from putrescine-starved cells of the double mutants MA 255 and MA 261, but not in the arginine-conditional auxotroph DK 6. Putrescine addition to the cultures of all these strains previously starved for polyamines, provoked a shift towards monomers in the equilibrium involving ribosomal particles. Concomitant changes in the intracellular levels of polyamines were observed: putrescine and spermidine increased markedly, and cadaverine disappeared.Dedicated to ProfessorLuis F. Leloir on the occasion of ths 70^th birthday.     

Characterization of glycerol nonutilizing and protoperithecial mutants ofNeurospora

Summary Mutants defective in polyol metabolism and/or in protoperithecial development were selected inNeurospora tetrasperma, a species in which protoperithecial development occurs at nonpermissively high temperature if certain polyols are used in lieu of sucrose as carbon source. Mutants selected for nonutilization of one of the four polyols tested, glycerol, mannitol, sorbitol, or xylitol, were usually found to be nonutilizers of the other three polyols as well. Mutants blocked at various stages of protoperithecial development complemented pairwise to produce more advanced developmental stages, usually mature protoperithecia and, when of opposite mating type, mature perithecia. About one-third of the mutants manifested both polyol auxotrophy and defective protoperithecial development upon initial isolation, but protoperithecial defectiveness in such mutants usually showed erratic segregation in crosses and/or instability to repeated vegetative transfer, whereas polyol auxotrophy usually did not and was, therefore, studied further. Two glycerol nonutilizing strains were introgressed intoN. crassa to facilitate genetic analysis. One,glp-4, lacked both inducible and constitutive glycerol kinase and mapped to linkage group VI, betweenad-1 andrib-1; the other,glp-5, lacked glyceraldehyde kinase and mapped to linkage group I, proximal toad-9. Another mutant,gly-u(234), has been reported by other investigators to lack inducible glycerol kinase but to map to linkage group I, distal toad-9.     

Calf development and mother-calf spatial relationships in Southern right whales

Changes in spatial relationships between mother and calf right whales (Eubalaena australis) from birth to the separation of yearling calves from their mothers were observed. During the first few weeks of a calf's life, mother and calf were within close proximity over 90% of the time, and mothers were responsible for maintenance of contact with their infants. Later calves strayed farther and initiated many more leaves and approaches than their quiescent mothers. The mothers still maintained contact with their infants. Just before migration away from the area, pair members resumed close proximity and leaves and approaches by both diminished. Yearling calves, returning to the area with their mothers after six months, stayed close to their mothers and few leaves and approaches by either pair member were recorded. The yearling calves were responsible for maintaining contact as the mothers left them more than approached them. This behaviour on the part of mothers probably contributed to weaning of yearlings and separation after a few weeks in the area.     

The effect of high buffer cardioplegia and secondary cardioplegia on cardiac preservation and postischemic functional recovery: a 31P NMR and functional study in Langendorff perfused pig hearts.

High buffer cardioplegia may provide protection against ischemic damage by reducing the extent of intracellular acidosis. Secondary cardioplegia may improve postischemic recovery by restoration of high energy phosphates, ionic gradients, and intracellular pH. To test these hypotheses, pig hearts were arrested with high buffer (150 mM MOPS) cardioplegia or modified St. Thomas' solution II and then kept ischemic at 12 degrees C for 8 h. High energy phosphates and intracellular pH were followed during the period of ischemia, using 31P nuclear magnetic resonance spectroscopy, and functional recovery was followed during reperfusion. The hearts arrested by high buffer cardioplegia showed significantly higher intracellular pH than hearts preserved with St. Thomas' solution, but there were no significant differences in high energy phosphates. There were no significant differences in functional recovery. We found, however, that secondary cardioplegia abolished ventricular fibrillation, and resulted in improved functional recovery after 8 h of ischemic preservation compared with the hearts reperfused with Krebs-Henseleit solution alone. Our results suggest that despite attenuating the decreases in intracellular pH, high buffer cardioplegia does not improve recovery following 8 h of preservation at 12 degrees C. Secondary cardioplegia reduces the incidence of ventricular fibrillation and improves postischemic functional recovery of the myocardium.