Miniaturized Cell Lysis Device Using Spherically Focused Ultrasound

A prototype of a miniaturized cell lysis device developed using a concave spherical transducer is capable of lysing bacteria without added chemical denaturants, enzymes or microparticles and is capable of efficiently lysing yeast without any mechanical or enzymatic pretreatment. The device is designed for miniature bio analysis systems where cell lysing is needed to obtain intracellular materials for further analysis such as DNA identification. The device lysis efficiency was evaluated using viable cell counts and microscopy. Additionally, the device efficiency was compared with that of traditional chemical cell lysis methods using standard molecular biological techniques such as agarose gels and ultraviolet (UV) spectroscopy. The results indicate that efficient bacteria and cell disruption can be achieved through a low voltage driven and spherically focused high frequency ultrasonic device.

The bacteriophage mu lysis system–A new mechanism of host lysis?

Bacteriophages are viruses that infect bacteria and can choose any one of the two alternative pathways for infection,i.e.,lysis or lysogeny.Phage lysis is one of the conventional biological processes required to spread infection from one bacterium to another.Our analysis suggests that in the paradigm bacteriophage Mu,six proteins might be involved in host cell lysis.Mu has a broad host range,and Mu-like phages were found in both Gram-negative and Gram-positive bacteria.An analysis of the genomes of Mu and Mu-like phages could be useful in elucidating the lysis mechanism in this group of phages.A detailed review of the various mechanisms of phage lysis and different proteins associated with the process will help researchers understand the phage biology and their life cycle in different bacteria.The recent increase in the number of multidrug-resistant(MDR)strains of bacteria and the usual long-term nature of new drug development has encouraged scientists to look for alternative strategies like phage therapy and the discovery of new lysis mechanisms.Understanding the lysis mechanism in the Mu-like phages could be exploited to develop alternative therapeutics to kill drug-resistant pathogenic bacteria.In this review article,we have analyzed the phage Mu-mediated host lysis system,which is unknown till now,and our analysis indicates a possibility of the existence of a new lysis mechanism operating in Mu.

Feasibility of using lysozyme to reduce excess sludge in activated sludge process

Lysozyme reaction was developed as a novel technique for minimizing the amount of excess sludge in the sequential batch reactor(SBR).In the present work,excess sludge taken from a SBR system was treated by lysozyme reaction and then returned to the reactor.The quality of the effluent water and characteristics of the activated sludge in the SBR were analyzed to determine the effectiveness of the reduction process.The results show that excess sludge production could be reduced to almost 100%in the first30 d of operation and could be reduced to further by 40%in the succeeding 20 d or so.In these time periods,the average removal efficiencies of the chemical oxygen demand and total nitrogen are 87.38%and 52.78%,respectively,whereas the average total phosphorous in the effluent is nearly 17.18%greater than that of the effluent of the reference system.After 50 d of operation,the sludge floc size is in the range of 20 to 80μm,which was smaller than the size prior to the start of the hydrolysis and the ratio of mixed liquor volatile suspended solids/mixed liquor suspended solids increases from 86%to 90%.