Cellulase production by free and immobilized <Emphasis Type=Italic>Aspergillus terreus</Emphasis>

Aspergillus terreus, isolated from rotting bagasse, showed comparable cellulolytic activities when grown either in the free or immobilized states with cellulose as the sole carbon source. The cultural and nutritional requirements for maximum cellulase production by the organism either in the free or immobilized states were similar, except an increase in the temperature optimum from 30 to 40°C, occurred upon immobilization. In the free state, the maximum filter paper hydrolase, carboxymethylcellulase and β-glucosidase activities produced were 2.1, 13.6, and 3.2 U/ml, respectively, while in the immobilized state, the levels were 1.8, 12.0, and 2.4 U/ml. Production of cellulolytic enzymes by immobilized cells was influenced by the surface area of the support material. In addition, cells in the immobilized state sustained enzyme production for a much longer period with a 4.5-fold increase in productivity during repeated batch when compared to free cells.     

Indigestible dextrin stimulates glucoamylase production in submerged culture of <Emphasis Type=Italic>Aspergillus kawachii</Emphasis>

Submerged batch cultures of Aspergillus kawachii grown on indigestible dextrin were investigated for potential improvements in glucoamylase (GA) production. In flask culture, specific GA productivities per dry weight biomass using dextrin and indigestible dextrin were 11.0 and 56.1 mU/mg-DW, respectively. Indigestible dextrin was a poor substrate for enzymatic hydrolysis. Rates of glucose formation from dextrin and indigestible dextrin by enzymatic hydrolysis were 0.477 and 0.100 mg-glucose/ml/h, respectively. For this reason, residual glucose concentrations in batch cultures grown on indigestible dextrin remained below 1.32 mg/ml where glucose-limiting conditions were easily maintained. Batch culture using indigestible dextrin had the same residual glucose profile as dextrin fed-batch culture, and nearly the same GA activity was obtained after 42.5 h of growth. However, between 42.5 and 66 h, the GA production rate of the indigestible dextrin batch culture (11.5 mU/ml/h) was higher than that of the dextrin fed-batch culture (6.5 mU/ml/h). During this period, a high amount of residual maltooligosaccharide was detected in the culture supernatant grown on indigestible dextrin. The high GA productivity observed in the indigestible dextrin batch culture may have resulted from the absence of glucose and the simultaneous presence of maltooligosaccharides throughout growth.     

Control of pyrimidine nucleotide formation in <Emphasis Type=Italic>Pseudomonas</Emphasis><Emphasis Type=Italic>fulva</Emphasis>

Control of pyrimidine formation was examined in Pseudomonas fulva ATCC 31418. Pyrimidine supplementation lowered pyrimidine biosynthetic pathway enzyme activities in cells grown on glucose or succinate as a carbon source indicating possible repression of enzyme synthesis. Pyrimidine limitation experiments were conducted using an orotidine 5′-monophosphate decarboxylase mutant strain isolated in this study. Compared to uracil-supplemented, glucose-grown mutant cells, pyrimidine limitation of this strain caused aspartate transcarbamoylase, dihydroorotase, dihydroorotate dehydrogenase and orotate phosphoribosyltransferase activities to increase about 6-, 13-, 3-, 15-fold, respectively, which confirmed regulation of enzyme synthesis by pyrimidines. At the level of enzyme activity, transcarbamoylase activity in Ps. fulva was strongly inhibited by pyrophosphate, CTP, GTP and GDP under saturating substrate concentrations.     

<Emphasis Type=Italic>In vitro</Emphasis> propagation and secondary metabolites production in wild germander (<Emphasis Type=Italic>Teucrium polium</Emphasis> L.)

A protocol for in vitro propagation of the wild germander (Teucrium polium L.) was developed. In vitro plants were developed from ex vitro axillary buds. Then, shoot tips were excised and established on Murashige and Skoog medium. Proliferation of shoots was tested with different levels of 6-furfurylaminopurin, 6-benzyladenine, or thiadiazuron. The highest proliferation of T. polium was obtained when 6-benzyladenine and 6-furfurylaminopurin were used at 2.0 and 1.6 mg l⁻¹, respectively. Thiadiazuron gave the lowest response for shoot proliferation. Rooting was experimented at different levels of Indol-3-butric acid, Indol-3-acetic acid, or 1-naphthaleneacetic acid. 1-Naphthaleneacetic was the only growth regulator which promoted root induction. Rooted plants were acclimatized successfully with 75% survival and grown in the greenhouse. In vitro- and in vivo-grown plants were analyzed for essential oil production. In vitro-grown T. polium on MS medium supplemented with 6-benzyladenine and 1-naphthaleneacetic gave higher oil yield than that grown on hormone-free Murashige and Skoog medium. In vivo (wild)-grown T. polium produced different oil yield when collected in different months (April and October). β-caryophyllene, used as a marker compound in the essential oil, was identified and quantified by gas chromatography (GC) analysis. Gas chromatography/mass (GC-MS) spectrometry analysis was also used to identify other components of in vitro cultures and to compare with in vivo-grown plants.     

Attenuation of fibrosis <Emphasis Type=Italic>in vitro</Emphasis> and <Emphasis Type=Italic>in vivo</Emphasis> with <Emphasis Type=Italic>SPARC</Emphasis> siRNA

Introduction  

SPARC is a matricellular protein, which, along with other extracellular matrix components including collagens, is commonly over-expressed in fibrotic diseases. The purpose of this study was to examine whether inhibition of SPARC can regulate collagen expression in vitro and in vivo, and subsequently attenuate fibrotic stimulation by bleomycin in mouse skin and lungs.     

<Emphasis Type=Italic>Motilin</Emphasis> and <Emphasis Type=Italic>ghrelin</Emphasis> gene experienced episodic evolution during primitive placental mammal evolution

Motilin and ghrelin, members of a structure-function-related hormone family, play important roles in gastrointestinal function, regulation of energy homeostasis and growth hormone secretion. We observed episodic evolution in both of their prehormone gene sequences during primitive placental mammal evolution, during which most of the nonsynonymous changes result in radical substitution. Of note, a functional obestatin hormone might have only originated after this episodic evolution event. Early in placental mammal evolution, a series of biology complexities evolved. At the same time the motilin and ghrelin prehormone genes, which play important roles in several of these processes, experienced episodic evolution with dramatic changes in their coding sequences. These observations suggest that some of the lineage-specific physiological adaptations are due to episodic evolution of the motilin and ghrelin genes.     

Efficient separation and purification of allophycocyanin from <Emphasis Type=Italic>Spirulina</Emphasis> (<Emphasis Type=Italic>Arthrospira</Emphasis>) <Emphasis Type=Italic>platensis</Emphasis>

Allophycocyanin (APC) is a minor component of phycobiliproteins in cyanobacteria and red algae. This paper describes a simple and inexpensive extracting method for isolating APC from Spirulina (Arthrospira) platensis with high efficiency. The crude phycobiliprotein extract was pretreated by ammonium sulfate fractionation. Then, by adding hydroxylapatite into crude phycobiliprotein extract dissolved in 20 mM phosphate buffer (pH 7.0), APC was selectively adsorbed by hydroxylapatite but C-phycocyanin (C-PC) was not. The hydroxylapatite was collected and APC was extracted from the crude phycobiliprotein extract. Then, the enriched APC was washed off from the hydroxylapatite using 100 mM phosphate buffer (pH 7.0). In this simple extracting method it was easy to remove C-PC and isolate APC in large amounts. The absorbance ratio A ₆₅₀/A ₂₈₀ of extracted APC reached 2.0. The recovery yield was 70%, representing 4.61 mg · g⁻¹ wet weight. The extracted APC could be further purified by a simple anion-exchange chromatography with a pH gradient from 5.6 to 4.0. The absorbance ratio A ₆₅₀/A ₂₈₀ of the purified APC reached 5.0, and the overall recovery yield was 43%, representing 2.83 mg · g⁻¹ wet weight. Its purity was confirmed by native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-PAGE.     

Interaction of <Emphasis Type=Italic>Bdellovibrio bacteriovorus</Emphasis> with bacteria <Emphasis Type=Italic>Campylobacter jejuni</Emphasis> and <Emphasis Type=Italic>Helicobacter pylori</Emphasis>

Interaction of Bdellovibrio bacteriovorus 100NCJB with bacteria Campylobacter jejuni (strains 1, 2, 3, 4, and 5) and Helicobacter pylori, strain TX30a, was confirmed. The results indicate that lytic activity of bdellovibrios both in liquid media and cells attached to a surface was observed. The potential use of the antimicrobial activity of predatory bacteria for environmental bioprotection and public health is discussed.     

<Emphasis Type=Italic>In vitro</Emphasis> organogenesis of <Emphasis Type=Italic>Passiflora alata</Emphasis>

Passiflora alata in vitro organogenesis was studied based on explant type, culture medium composition, and incubation conditions. The results indicated that the morphogenic process occurred more efficiently when hypocotyl segment-derived explants were cultured in media supplemented with cytokinin and AgNO₃ incubated under a 16-h photoperiod. The shoot bud elongation and plant development were obtained by transferring the material to MSM culture medium supplemented with GA₃ and incubated in flasks with vented lids. Histological analyses of the process revealed that the difficulties in obtaining plants could be related to the development of protuberances and leaf primordia structures, which did not contain shoot apical meristem. Roots developed easily by transferring elongated shoots to 1/2 MSM culture medium. Plant acclimatization occurred successfully, and somaclonal variation was not visually detected. The efficiency of this organogenesis protocol will be evaluated for genetic transformation of this species to obtain transgenic plants expressing genes that can influence the resistance to Cowpea aphid borne mosaic virus.     

Presence of <Emphasis Type=Italic>C. albidus</Emphasis>, <Emphasis Type=Italic>C. laurentii</Emphasis> and <Emphasis Type=Italic>C. uniguttulatus</Emphasis> in Crop and Droppings of Pigeon Lofts (<Emphasis Type=Italic>Columba livia</Emphasis>)

Columba livia is an important reservoir and carrier of Cryptococcus neoformans, Cryptococcus uniguttulatus, Cryptococcus laurentii and Cryptococcus albidus. Upper digestive tract of this species is also known as a habitat for Cryptococcus neoformans. Given the increasing clinical interest of this microorganism, 331 swabs from crop and 174 dropping samples from pigeon lofts in Grand Canary Island have been studied. The obtained results show an extensive presence samples 81 positive (24.47%) of Cryptococcus spp. in analysed crops: 32 (9.66%) for C. neoformans, 24 (7.2%) for C. uniguttulatus, 23 (6.9%) for C. albidus and 2 (0.6%) for C. laurentii. In the same way, Cryptococcus spp was also isolated in 82 (47.13%), dropping samples: C. neoformans in 59 (33.9%), C. uniguttulatus, in 9 (5.17%), C. laurentii in 8 (4.59%) and C. albidus in 6 (3.44%) of the investigated samples, respectively. The cryptococcosis produced by species of cryptococci other than C. neoformans has become more important during the last decade, supporting the study on the role of pigeon in the epidemiology of this disease.     

<Emphasis Type=Italic>Pseudomonas aeruginosa</Emphasis> inhibits <Emphasis Type=Italic>in-vitro Candida</Emphasis> biofilm development

Background  

Elucidation of the communal behavior of microbes in mixed species biofilms may have a major impact on understanding infectious diseases and for the therapeutics. Although, the structure and the properties of monospecies biofilms and their role in disease have been extensively studied during the last decade, the interactions within mixed biofilms consisting of bacteria and fungi such as Candida spp. have not been illustrated in depth. Hence, the aim of this study was to evaluate the interspecies interactions of Pseudomonas aeruginosa and six different species of Candida comprising C. albicans, C. glabrata, C. krusei, C. tropicalis, C. parapsilosis, and C. dubliniensis in dual species biofilm development.