Inactivation of bleomycin by an N-acetyltransferase in the bleomycin-producing strain Streptomyces verticillus

Abstract Bleomycin-producing Streptomyces verticillus ATCC15003 possesses a bleomycin acetyltransferase which inactivates the drug in the presence of acetyl coenzyme A. The site of acylation in enzymically prepared acetylbleomycin A2 was determined by nuclear magnetic resonance analysis; the primary amino group of the β-aminoalanine moiety of bleomycin was acetylated. Acetylbleomycin A2 had no detectable antibacterial activity and did not induce in vitro DNA degradation.     

Agave studies in Yucatan,Mexico. II. Nutritional value of the inflorescence peduncle and incipient domestication

Recent ethnobotanical exploration of henequen (Agave fourcroydes) in the Peninsula of Yucatan, Mexico, finds that inflorescence peduncles are used as emergency food and in the preparation of a fermented drink. Bromatological analysis and determination of total carbohydrates were made for the two length classes (ca. 3.30 m and ca. 0.60 m) which are consumed. The analysis of both the cultivated plant and its putative wild ancestor (Agave angustifolia) suggests that utilization of the inflorescence peduncles as food may have been involved in the initial stages of the history of its evolution under artificial selection, because the wild and the cultivated plants have similar palatability. The subsequent agricultural prevalence of annual crop species in the region was possibly responsible for the abandonment of henequen in the local diet. No significant differences are observed between the bromatological and total carbohydrate values of domesticated and wild plants. The preference for small inflorescence peduncles as a vegetable is a consequence of its significantly minor content of raw fiber and its larger content of total carbohydrates. As a fermented drink, longer peduncles are preferred because they provide more substrate material and because fiber can be eliminated by filtering. This agricultural byproduct, almost totally wasted, has potential value as a source of carbohydrates and raw fiber.     

Formation of crystalloid inclusions in the small intestine of neonatal pigs: an immunocytochemical study using colloidal gold

Summary Enterocytes of the small intestine in 1-day-old suckling piglets contain numerous vesicles in the apical cytoplasm and a large granule located beneath the nucleus. Within the next 3 days, these granules transform into electron-dense crystalloid inclusions. These membrane-bound inclusions are up to 10 m in length and 1–2 m in diameter, and they are composed of electron-dense lamellae 3.9 nm apart. Postembedding immunocytochemistry, using rabbit anti-porcine IgG and goat anti-rabbit IgG conjugated to 10 nm colloidal gold, revealed that both the granules and the crystalloid inclusions contained a high concentration of maternal IgG. Although the IgG content of the crystalloid inclusions was detected on epoxy-embedded sections, the use of LR White resin resulted in a much higher density of labelling. Quantification of the labelling density showed that the concentration of IgG in the crystalloid inclusions was approximately ten times higher than that in the lumenal colostrum and approximately three times higher than that in the granules. These observations showed that there are at least three compartments involved in the accretion of IgG in the small intestine of neonatal piglets: smaller apical endocytotic vesicles, large subnuclear granules and crystalloid inclusions. The role of these compartments in maternal immunoglobulin absorption and in the acquisition of passive immunity has yet to be explored.     

Selenium in combination with a tomato lipid extract as a therapy for benign prostatic hyperplasia and its alterations in rats with induced BPH

Benign prostatic hyperplasia (BPH) is the most common adenoma in old men. Tomatoes are a rich source of bioactive compounds that, as well as selenium (Se), possess antioxidant and antiproliferative activity. The aim was to evaluate the therapeutic effect of Se in combination with a tomato extract in aged rats with BPH. Aged male Wistar rats were divided in the following groups (n = 10 rats/group): Control (C), BPH, BPH + Finasteride (BPH + F), BPH + Tomato Lipidic Extract (BPH + E), BPH + Selenium (BPH + S) and BPH plus E plus S (BPH + E + S). After 4 weeks of treatment, prostate weight, diuresis, antioxidants enzymes, prooxidants and inflammatory markers, growth factors and androgens were determined. BPH + E + S reduced prostate weight by 59.29% and inhibited growth by 99.35% compared to BPH + F which only decreased weight and inhibited growth by 15.31% and 57.54%, respectively. Prooxidant markers were higher with BPH + F (49.4% higher vs. BPH), but BPH + E + S decreased these markers (94.27% vs. BPH) and increased antioxidant activity. Finally, diuresis was higher with the BPH + E + S combination and markers of inflammation and growth factors were significantly lower with respect to BPH + F. Our findings provide a beneficial and protective therapeutic option of E + S directed against androgens, oxidative stress and inflammation that regulates cell proliferation in the prostate gland.     

Engineered nickel bioaccumulation in Escherichia coli by NikABCDE transporter and metallothionein overexpression

Mine wastewater often contains dissolved metals at concentrations too low to be economically extracted by existing technologies, yet too high for environmental discharge. The most common treatment is chemical precipitation of the dissolved metals using limestone and subsequent disposal of the sludge in tailing impoundments. While it is a cost-effective solution to meet regulatory standards, it represents a lost opportunity. In this study, we engineered Escherichia coli to overexpress its native NikABCDE transporter and a heterologous metallothionein to capture nickel at concentrations in local effluent streams. We found the engineered strain had a 7-fold improvement in the bioaccumulation performance for nickel compared to controls, but also observed a drastic decrease in cell viability due to metabolic burden or inducer (IPTG) toxicity. Growth kinetic analysis revealed the IPTG concentrations used based on past studies lead to growth inhibition, thus delineating future avenues for optimization of the engineered strain and its growth conditions to perform in more complex environments.     

The importance of ecological research for ecosystem management: The case of browsing by swamp wallabies (Wallabia bicolor) in commercially harvested native forests

Summary Ecosystem management often proceeds within the context of sub‐optimal relationships between ecologists and ecosystem managers, and management outcomes could be improved with greater collaboration between members of these disciplines. This paper identifies an ecosystem management problem resulting from the interaction between timber harvesting and browsing wallabies, and this case study is used to exemplify how ecological data and expertise can contribute to the process of ecosystem management. It is argued that appropriate use of existing ecological data, establishment of strategic new research and the implementation of management actions as experimental hypothesis tests can facilitate achievement of management objectives, but greater collaboration between ecologists and managers is required before this can occur. Reasons for sub‐optimal relationships are outlined, and the potential for structural change within large State‐run ecosystem management agencies to improve interactions between managers and ecologists is discussed.     

Experimental dissociation of the effects of diet, age and breeding experience on primary reproductive effort in zebra finches Taeniopygia guttata

Reproductive performance varies with age in a wide range of organisms, and increasingly such patterns are interpreted in terms of state-dependent models. We sought to characterise 'state' with regards to age-related variation in clutch size, egg mass and timing of breeding in captive zebra finches Taeniopygia guttata , focusing on the roles of diet quality, age and breeding experience. Females on a high-quality diet laid larger clutches of larger eggs than did females on a low-quality diet. The effect of age on reproductive performance was examined by comparing females breeding (i.e. paired) for the first time at either 3- and/or 6-months of age. Clutch size increased with age but on the low-quality diet only, not on the high-quality diet. Furthermore, clutch size decreased between 3- and 6-months of age in birds bred first on the high-quality diet and then on the low-quality diet. Age did not affect egg mass but older birds had shorter laying intervals. Reproductive performance did not differ between females breeding at 6-months of age for the first or second time: the effects of age were not due to 'training' effects or experience specific to breeding (e.g. undergoing the physiological process of egg formation). In conclusion, nutritional condition (diet) emerged as a central component of state that could strongly influence, and even reverse, any age-dependent increase in primary reproductive performance.     

Object-oriented graphical modeling of FMSs

Presented in the article is a method for constructing a graphical model of an FMS by using a new modeling tool called JR-net (Job Resource relation-net). JR-net is an object-oriented graphical tool for modeling automated manufacturing systems (AMSs), such as FMSs, FASs, and AS/RSs. As with the object-oriented modeling paradigm of Rumbaugh et al. (1991), the JR-net modeling framework supports the three stages of models: static layout model (object model); job flow model (functional model); and supervisory control model (dynamic model). In this article, the existing JR-net structure (Park 1992, Han et al., 1995) is extended further to make it a graphical tool for FMS modeling. Using the extended JR-net, a step-by-step procedure for constructing a graphical model of FMSs is presented. Also addressed are issues of classifying FMSs in terms of their generic functions and of utilizing the JR-net model of FMSs.