Phages are now acknowledged as the most abundant microorganisms on the planet and are also possibly the most diversified. This diversity is mostly driven by their dynamic adaptation when facing selective pressure such as phage resistance mechanisms, which are widespread in bacterial hosts. When infecting bacterial cells, phages face a range of antiviral mechanisms, and they have evolved multiple tactics to avoid, circumvent or subvert these mechanisms in order to thrive in most environments. In this Review, we highlight the most important antiviral mechanisms of bacteria as well as the counter-attacks used by phages to evade these systems.

Bacteriophage resistance mechanisms.

Foreign gene expression in yeast: a review.

Factors affecting the fermentative lactic acid production from renewable resources1

Fungal morphology and metabolite production in submerged mycelial processes.

Microbial production of organic acids: expanding the markets.

The production of organic acids covers two aspects: first, the metabolic pathways involved in the biosynthesis, and, second, the industrial process strategy adopted The review seeks to show the underlying biochemical similarities in the biosynthesis of organic acids and the resulting similarities in the commercial processes Two groups of acids are defined, those with a "long" biosynthetic path from glucose, involving much of the glycolytic pathway and the tricarboxylic acid cycle, and those acids with a "short pathway", essentially a biotransformation of glucose The regulation of the pathways and the future developments in metabolic control theory and genetic manipulations relating to them are considered The organisms used industrially are also limited, Aspergillus sp and Candida yeasts; again the underlying metabolic similarities lead to similar strategies for all the acids discussed

The production of organic acids.

Seventy-seven children between the ages of 6 and 10 years, with severe mixed receptive-expressive specific language impairment (SLI), participated in a randomized controlled trial (RCT) of Fast ForWord (FFW; Scientific Learning Corporation, 1997, 2001). FFW is a computer-based intervention for treating SLI using acoustically enhanced speech stimuli. These stimuli are modified to exaggerate their time and intensity properties as part of an adaptive training process. All children who participated in the RCT maintained their regular speech and language therapy and school regime throughout the trial. Standardized measures of receptive and expressive language were used to assess performance at baseline and to measure outcome from treatment at 9 weeks and 6 months. Children were allocated to 1 of 3 groups. Group A (n = 23) received the FFW intervention as a home-based therapy for 6 weeks. Group B (n = 27) received commercially available computer-based activities designed to promote language as a control for computer games exposure. Group C (n = 27) received no additional study intervention. Each group made significant gains in language scores, but there was no additional effect for either computer intervention. Thus, the findings from this RCT do not support the efficacy of FFW as an intervention for children with severe mixed receptive-expressive SLI.

/pdf/effects-of-computer-based-intervention-through-acoustically-5diw8in9bt.pdf

Effects of computer-based intervention through acoustically modified speech (Fast ForWord) in severe mixed receptive-expressive language impairment: outcomes from a randomized controlled trial.

Although the citric acid fermentation by Aspergillus niger is one of the most important industrial microbial processes and various aspects of the fermentation appear in a very large number of publications since the 1950s, the effect of the spore inoculum level on fungal morphology is a rather neglected area. The aim of the presented investigations was to quantify the effects of changing spore inoculum level on the resulting mycelial morphology and to investigate the physiology that underlines the phenomena. Batch fermentations were carried out in a stirred tank bioreactor, which were inoculated directly with spores in concentrations ranging from 104 to 109 spores per ml. Morphological features, evaluated by digital image analysis, were classified using an artificial neural network (ANN), which considered four main object types: globular and elongated pellets, clumps and free mycelial trees. The significance of the particular morphological features and their combination was determined by cluster analysis. Cell volume fraction analysis for the various inoculum levels tested revealed that by rising the spore inoculum level from 104 to 109 spores per ml, a clear transition from pelleted to dispersed forms occurs. Glucosamine formation and release by the mycelium appears to be related to spore inoculum level. Maximum concentrations detected in fermentations inoculated with 104 and 105 spores/ml, where pellets predominated. At much higher inoculum levels (108, 109 spores/ml), lower dissolved oxygen levels during the early fermentation phase were associated with slower ammonium ions uptakes and significantly lower glucosamine concentrations while the mycelium developed in dispersed morphologies. A big increase in the main and total hyphal lengths and branching frequency was observed in mycelial trees as inoculum levels rise from 104 to 109 spores/ml, while in aggregated forms particle sizes and their compactness decreased. The methods used in this study, allowed for the detailed quantification of the transition between the two extreme morphological forms. The impact of spore inoculum level on the detailed characteristics of the particular morphological forms produced was high. Control of mycelial morphology is often regarded as a prerequisite to ensure increased productivities in industrial applications. The research described here demonstrates that adjusting the spore inoculum level controls effectively mycelial morphology.

/pdf/morphological-development-of-aspergillus-niger-in-submerged-oimfl37p7d.pdf

Morphological development of Aspergillus niger in submerged citric acid fermentation as a function of the spore inoculum level. Application of neural network and cluster analysis for characterization of mycelial morphology.

Citric acid biotechnology is the subject of both industrial and academic interest. For a long time the production of citric acid was one of the driving forces in industrial biotechnology, lying in the interface between old and new technology. Now, not only is citric acid biotechnology of great industrial and economic importance, it is also used to illustrate biotechnological principles at undergraduate level. This comprehensive book covers subjects such as mycology redox reactions mass and energy balances downstream processing fermentation substrates and design of industrial plants. All the authors are still active in the field and come from both industrial and academic backgrounds. Undergraduates and postgraduates studying industrial microbiology, biotechnology or biochemical engineering, or those wishing to pursue careers in the biotechnological industry will find this a comprehensive, accessible and definitive resource. It will also provide a useful reference for researchers and managers in the industry.

Michael Mattey

Papers

The production of organic acids.

Effects of computer-based intervention through acoustically modified speech (Fast ForWord) in severe mixed receptive-expressive language impairment: outcomes from a randomized controlled trial.

Morphological development of Aspergillus niger in submerged citric acid fermentation as a function of the spore inoculum level. Application of neural network and cluster analysis for characterization of mycelial morphology.

Citric Acid Biotechnology

The influence of glucose concentration on citric acid production and morphology of Aspergillus niger in batch and culture