Antibacterial activity of snake, scorpion and bee venoms: a comparison with purified venom phospholipase A2 enzymes

AIMS: Venoms of snakes, scorpions, bees and purified venom phospholipase A(2) (PLA(2)) enzymes were examined to evaluate the antibacterial activity of purified venom enzymes as compared with that of the crude venoms. METHODS AND RESULTS: Thirty-four crude venoms, nine purified PLA(2)s and two L-amino acid oxidases (LAAO) were studied for antibacterial activity by disc-diffusion assay (100 microg ml(-1)). Several snake venoms (Daboia russelli russelli, Crotalus adamanteus, Naja sumatrana, Pseudechis guttata, Agkistrodon halys, Acanthophis praelongus and Daboia russelli siamensis) showed activity against two to four different pathogenic bacteria. Daboia russelli russelli and Pseudechis australis venoms exhibited the most potent activity against Staphylococcus aureus, while the rest showed only a moderate activity against one or more bacteria. The order of susceptibility of the bacteria against viperidae venoms was -S. aureus > Proteus mirabilis > Proteus vulgaris > Enterobacter aerogenes > Pseudomonas aeruginosa and Escherichia coli. The minimum inhibitory concentrations (MIC) against S. aureus was studied by dilution method (160-1.25 microg ml(-1)). A stronger effect was noted with the viperidae venoms (20 microg ml(-11)) as compared with elapidae venoms (40 microg ml(-1)). The MIC were comparable with those of the standard drugs (chloramphenicol, streptomycin and penicillin). CONCLUSION: The present findings indicate that viperidae (D. russelli russelli) and elapidae (P. australis) venoms have significant antibacterial effects against gram (+) and gram (-) bacteria, which may be the result of the primary antibacterial components of laao, and in particular, the PLA(2) enzymes. The results would be useful for further purification and characterization of antibacterial agents from snake venoms. SIGNIFICANCE AND IMPACT OF THE STUDY: The activity of LAAO and PLA(2) enzymes may be associated with the antibacterial activity of snake venoms.     

Detection and analysis of tumor fluorescence using a two-photon optical fiber probe

The utility of a two-photon optical fiber fluorescence probe (TPOFF) for sensing and quantifying tumor fluorescent signals was tested in vivo. Xenograft tumors were developed in athymic mice using MCA207 cells expressing green fluorescent protein (GFP). The TPOFF probe was able to detect ex vivo fluorescence from excised tumors containing as little as 0.3% GFP-expressing cells. TPOFF results were similar to both flow-cytometric analysis of tumor cells after isolation and suspension, and fluorescence determined by microscope images of cryosectioned tumors. TPOFF was then used to measure GFP fluorescence from tumors in live mice. The fiber probe detected fluorescently-labeled Herceptin antibody targeted to HER2-expressing tumors in severe combined immunodeficient mice. Dendrimer nanoparticles targeted by folic acid and having 6-TAMRA as a fluorescent probe were also used to label KB cell tumors in vivo. The fiber probe documented a fourfold increase in tumor fluorescence in animals that received the targeted dendrimer. These results suggest TPOFF can be used as a minimally invasive system for identifying tumor markers and monitoring drug therapy.     

Novel microbial nitrogen removal processes

The present-day wastewater treatment practices can be significantly improved through the introduction of new microbial treatment technologies. Recently, several new processes for nitrogen removal have been developed. These new nitrogen removal technologies provide practicable options for treating nitrogen-laden wastewaters. The new processes are based on partial nitrification of ammonium to nitrite combined with anaerobic ammonium oxidation. These processes include the single reactor system for high ammonia removal over nitrite (SHARON) process, which involves part conversion of ammonium to nitrite; the anaerobic ammonium oxidation (ANAMMOX) process, which involves anaerobic ammonium oxidation; and the completely autographic nitrogen removal over nitrite (CANON) process, which involves nitrogen removal within one reactor under oxygen-limited conditions. These new processes target the removal of nitrogen from wastewaters containing significant quantities of ammonium.     

IL-4抑制Lewis肺癌生长和转移的实验研究

探讨 IL -4对 Lewis肺癌生长和转移的抑制作用。将 Lewis肺癌细胞接种于 C57BL /6小鼠皮下。将 2 0只小鼠随机分为两组 ,接种后第 5天起分别给予生理盐水或 IL-4。第 1 8天处死动物 ,测两组肿瘤的平均体积 ,平均瘤重及肺转移灶。 、 组肿瘤的平均体积为 ( 2 .0 0 7± 0 .0 0 6) cm3 ,( 0 .4 0 4± 0 .0 1 0 ) cm3 ;平均瘤重为 ( 2 .83 3± 0 .0 74 ) g、( 0 .586± 0 .0 4 0 ) g,肺转移灶为 ( 5.50 0± 0 .92 6) ,( 3 .3 75± 1 .0 61 )。 组与 I组比差异有显著性 ( P<0 .0 5) ;平均潜伏期为 :8.3 0± 0 .4 9;1 0 .56± 0 .3 6。 IL-4能抑制 Lewis肺癌生长和转移。     

Male-female larval interactions in Schistosoma mansoni-infected Biomphalaria glabrata

This paper investigates Schistosoma mansoni male-female larval interactions in simultaneous bi-miracidial Biomphalaria glabrata infections. Larval interactions were analysed at four levels of infection: (i), miracidial infectivity, estimated by the prevalence of mollusc infection; (ii), mollusc pathology, measured by the mollusc growth and survival; (iii), dynamics of the cercarial sex ratio; and (iv), cercarial infectivity, measured as the success of development into adulthood. Our results showed that larval interactions exist in S. mansoni-infected B. glabrata. These interactions do not occur in miracidial infectivity, but occur in mollusc pathology, cercarial sex ratio dynamics and cercarial infectivity. Regarding mollusc pathology, we showed that the bi-miracidially-infected molluscs were smaller than the mono-miracidially-infected ones. This could be the result of larval competition. Regarding the dynamics of the cercarial sex ratio, we showed larval female superiority as compared with male larvae inducing the shedding of female-biased cercarial sex ratios. These sex ratios were rhythmic and could be the reflection of an external expression of the intramolluscan development. Regarding cercarial infectivity, we showed that the simultaneous presence of both sexes in a mollusc increased the cercarial infectivity. This result could be due to male-female larval synergism.     

Helminth eggs in animal coprolites from a Middle Pleistocene site in Europe

This paper reports on the discovery of dicrocoelid eggs in a coprolite collected in an archeological layer dated earlier than 550,000 yr BP (before present) from the Caune de l'Arago cave (Tautavel, Pyrénées-Orientales, France). It is the first trematode egg finding in an isolated coprolite from the Middle Pleistocene context.     

Establishment of a Captive All‐male Group of Proboscis Monkey (Nasalis larvatus) at the Singapore Zoo

Surplus male proboscis monkeys at the Singapore Zoo pose a considerable problem for maintenance and maximizing of exhibition potential. In 2008, a new exhibit was constructed to house and display a group of six proboscis monkey males born in Singapore Zoo. To document and monitor the all‐male group establishment in the new exhibit, we conducted observations on intragroup interactions between the monkeys, spatial use of their new exhibit, and visitor effects on their behavior. We found contact aggressive interactions between the monkeys to be consistently lower than noncontact aggressive interactions and by week six of introduction to the new exhibit, contact aggression was almost nonevident. Affiliative interactions also developed between individuals in the group, with an interface of aggressive and socioreconcilatory behavior influenced by food competition and a dominance hierarchy. This was evident from significantly higher overall aggression and affiliation during feeding times compared to nonfeeding times, and this was reduced when food competition was mitigated by modifying the feeding regime. We measured the groups’ spatial use of the exhibit and the relation to behavior, crowd size, and density. Our results showed that the proboscis monkeys utilized the available exhibit space, were largely unaffected by visitor crowd size and density, and were able to exhibit a variety of natural behaviors, including swimming. Our accomplishment in maintaining and displaying an all‐male group of proboscis monkeys in captivity provides viable options for more comprehensive captive management and breeding programs for this endangered species. Zoo Biol. 32:281‐290, 2013. © 2012 Wiley Periodicals, Inc.