Prokaryotic microbiota of recycled paper mills with low or zero effluent

The tendency in the paper industry is to close all water loops to save water. This leads to higher process temperatures and may increase the colloidal and dissolved material in the process circulation. Increase of nutrients in the water circuits may favor microbiological growth and fouling. In this paper the chemical and microbial compositions of water circuits and deposits were studied of two closed cycled paper/board mills, one mill totally closed (0 m(3) waste water t(-1)), and the other low discharging (about 4 m(3 )t(-1)). The zero discharge mill accumulated high amounts (>10 g C L(-1)) of organic carbon in the circulation waters, about 40% of which composed of volatile acids (lactic, acetic, propionic and butyric acid). Water contents of sulfate, chloride, sodium and calcium increased to >1 g L(-1) of each. q-PCR targeted on 16S rRNA genes indicated that the bacteria in water circuits were mainly viable cells. In both mills anaerobic growth (10(6)-10(8) CFU mL(-1)) equalled or exceeded aerobic growth, with odor problem but no actual slime problem. The major part (40%) of all identifiable bacterial sequences were closest but yet distant (<96%) to Enterococcus cecorum and in the 4 m(3 )t(-1) discharging mill also Bacillus thermoamylovorans and Bacillus coagulans. Slimes and deposits from the mills contained high amounts, >/=10(8) g(-1), of archaean, but only the genus Methanothrix was identifiable from the cloned sequences. The findings indicate that closing the water circuits strongly limited diversity of the microbiota but allowed efficient mineralization of the dissolved and suspended matter.     

Association of Viral Reverse Transcriptase with an Enzyme degrading the RNA Moiety of RNA-DNA Hybrids

DURING replication of RNA tumour viruses, the genetic information contained in the viral RNA seems to be transferred to DNA^1,2. Studies on the enzymatic activities present in the virus particles suggest that this transfer is mediated by an RNA dependent DNA polymerase^3,4. RNA-DNA hybrids have been demonstrated to occur as intermediates in this reaction⁵ and single stranded DNA is generated as an early reaction product⁶, which is then replicated to give a double stranded DNA product^6–8. The mechanism by which the single stranded DNA is displaced from the RNA template is, however, not known.     

Antioxidant status in cerebrovascular accident

Ischemia is associated with the pathological changes caused by the accumulation of reactive oxygen metabolites (ROM) in cerebrovascular accident (CVA). The aim of this study was to determine red cell copper/zinc-superoxide dismutase (Cu/Zn-SOD) and catalase activities and copper and zinc concentrations both in plasma and in red cells in CVA. Cu/Zn-SOD and catalase activities of 16 patients, with an average age of 64 yr, were measured spectrophotometrically; copper and zinc concentrations were determined by atomic absorption spectrophotometer. The results showed that Cu/Zn-SOD activity was increased markedly in patients compared to the young controls and reached a peak on the d 5 of the disease, whereas the catalase activity of the patients on d 3 and d 5 were in the normal range, but higher on d 10. The enzyme activities of the elderly group were generally increased compared to the young controls. Copper and zinc concentrations showed corresponding alterations. These findings suggested that the effects of oxidative stress in CVA might be reflected in red cell and plasma parameters. Presented at the III International Congress of Pathophysiology, Lahti, Finland, 28 June–3 July, 1998.     

HPLC-DAD Analysis and Versatile Bioactivities of Turkish Sunflower Honeys Using Chemometric Approaches

Sunflower honey (SH) is bright yellow, fragrant, pollen-flavoured, slightly herbaceous and has a unique taste. The present research aims to examine the enzyme inhibitory, antioxidant, anti-inflammatory, antimicrobial and anti-quorum sensing activities and phenolic compositions of 30 sunflower honeys (SHs) produced from several regions of Turkey with chemometric study. SAH from Samsun exhibited the best antioxidant activity in β-carotene linoleic acid (IC₅₀: 7.33±0.17 mg/mL) and CUPRAC (A_0.50: 4.94±0.13 mg/mL) assays, anti-urease activity (60.63±0.87 %) and anti-inflammatory activity against COX-1 (73.94±1.08 %) and COX-2 (44.96±0.85 %). SHs exhibited mild antimicrobial activity against the test microorganisms while they showed high quorum sensing inhibition zones measured in the range of 42–52 mm against the CV026 strain. The phenolic composition was determined by high performance liquid chromatography with diode array detection (HPLC-DAD) system and levulinic, gallic, p-hydroxybenzoic, vanillic and p-coumaric acids were identified in all studied SHs. The classification of SHs was performed the using PCA and HCA. This study revealed that phenolic compounds and biological properties are effective in classification of SHs according to their geographical origin. The results suggest that studied SHs could be valued as potential agents with versatile bioactivities in oxidative stress-related disease, microbial infections, inflammation, melanoma, and peptic ulcer.     

Effect of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions

Micro-aeration, which refers to the addition of very small amounts of air, is a simple technology that can potentially be incorporated in septic tanks to improve the digestion performance. The purpose of this study was to investigate and compare the effects of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions. 1.6 L batch reactor experiments were carried out in duplicate using raw primary sludge, with 4.1 % total solids, and diluted primary sludge, with 2.1 % total solids. Reactors were operated for 5 weeks at room temperature to simulate septic tank conditions. Micro-aeration rate of 0.00156 vvm effectively solubilised chemical oxygen demand (COD) and improved the subsequent degradation of COD. Micro-aeration also increased the generation of ammonia and soluble proteins, but did not improve the reduction in total and volatile solids, or the reduction in carbohydrates. Experiments using diluted sludge samples showed similar trends as the experiments with raw sludge, which suggest that initial solids concentration did not have a significant effect on the degradation of primary sludge under septic tank conditions.     

The composition of arbuscular mycorrhizal fungal communities differs among the roots,spores and extraradical mycelia associated with five Mediterranean plant species

Arbuscular mycorrhizal fungi (AMF) are essential constituents of most terrestrial ecosystems. AMF species differ in terms of propagation strategies and the major propagules they form. This study compared the AMF community composition of different propagule fractions – colonized roots, spores and extraradical mycelium (ERM) – associated with five Mediterranean plant species in Sierra de Baza Natural Park (Granada, Spain). AMF were identified using 454 pyrosequencing of the SSU rRNA gene. A total of 96 AMF phylogroups [virtual taxa (VT)] were detected in the study site, including 31 novel VT. After per‐sample sequencing depth standardization, 71 VT were recorded from plant roots, and 47 from each of the spore and ERM fractions. AMF communities differed significantly among the propagule fractions, and the root‐colonizing fraction differed among host plant species. Indicator VT were detected for the root (13 Glomus VT), spore (Paraglomus VT281, VT336, Pacispora VT284) and ERM (Diversispora VT62) fractions. This study provides detailed evidence from a natural system that AMF taxa are differentially allocated among soil mycelium, soil spores and colonized root propagules. This has important implications for interpreting AMF diversity surveys and designing applications of AMF in vegetation restoration.     

Double promoter expression systems for recombinant protein production by industrial microorganisms

Applied Microbiology and Biotechnology - Using double promoter expression systems is a promising approach to increase heterologous protein production. In this review, current double promoter...     

Hypertonic Sabouraud Dextrose Agar as a Substrate for Differentiation of Candida dubliniensis

In this study, we aimed to detect the proportion of Candida dubliniensis among yeast strains previously identified as C. albicans by using several phenotypic methods and PCR. For this purpose, we screened 300 strains by using phenotypic tests suggested for the identification of C. dubliniensis in the literature, but we detected high proportion of false-positive reactions. Only two strains (0.6%) were detected as true C. dubliniensis by PCR and API ID 32C methods. Moreover, these two strains gave the expected results with all the phenotypic tests, including modified salt tolerance test for C. dubliniensis. In conclusion, none of the phenotypic methods, except for the modified salt tolerance test, revealed 100% successful results in discrimination of C. albicans and C. dubliniensis species. However, in the tobacco agar test, the rate of false positivity was as low as 0.6%. We suggest that in the case of absence of PCR and other automatized identification systems, these two phenotypic tests can be used in routine laboratories to obtain a presumptive result.