Biomedical Engineering Reference
In-Depth Information
exhibited extensive inhibitory effect on human breast cancer cells. Therefore, they
suggested that rhamnolipids produced by
P. aeruginosa
B189 is an effective com-
pound for using in anticancer drugs.
McClure and Schiller (1992) described the cytolytic activity of rhamnolipids on
human monocyte-derived macrophages (MDMs); they found out that the dirhamno-
lipids were much more effective than monorhamnolipids and could cause blebbing of
the plasma membrane of human MDM. Although the exact mechanisms responsible
for rhamnolipid activities are not well identified, they suggested that one of the pos-
sible mechanisms is through the insertion of the fatty acid tails of the rhamnolipids
into the cell membrane.
Kamal et al. (2012) reported the isolation of a new strain of
Pseudomonas
from
an alkaline soil from a cold desert located in the Western Himalayas. These resilient
bacteria had to survive the cold temperature of the region and an extreme hot temper-
ature during a short period in the summer and UV irradiation. By conducting analy-
sis with NMR, FITR, and MS, they found that the
Pseudomonas
strain ICTB-745
was able to produce four different bioactive substances: monorhamnolipids, dirham-
nolipids, 1-hydroxyphenazine, and phenazine-1-carboxylic acid. They reported that
the produced compounds could perform as a highly effective antimicrobial against
both gram-positive and gram-negative bacteria, as well as
Candida albicans
; they
also demonstrated cytotoxic activities against human tumor cells.
B
ioDeGraDaBility
of
r
hamnoliPiDs
In natural habitats, some bacteria could secret enzymes such as lipases, lipoyl
synthase, and triacylglycerol lipase, which are able to break down the rhamnolipid
(Wittgens et al., 2011). Chrzanowski et al. (2012) stated that the result of their experi-
ments demonstrated that the microorganisms present in the soil, which are responsible
for biodegradation of hydrocarbons, could easily degrade rhamnolipids as well. This
biodegradation could occur in both aerobic and anaerobic conditions. It was observed
that the biodegradation of rhamnolipids didn't interfere with the biodegradation rate
of diesel in the soil. The observation of Chrzanowski et al. (2012) showed that the
presence of rhamnolipids in soil and their biodegradation didn't favor the growth of
the specific species, so it doesn't alter the natural microbial equilibrium in the soil.
This proves that rhamnolipids are ecologically friendly substances. Nitschke et al.
(2011) stated that one of the advantages of using rhamnolipids instead of their syn-
thetic counterpart is their biodegradability, although there is a need for more research
on the possibility of their toxicities on living organisms in the environment. Moreover,
according to Wena et al. (2009), the rate of rhamnolipid degradation depends on the
percentage of contamination in soil, and the highest rate of degradation was observed
in contaminated sites and the lowest rate was in uncontaminated soils.
METHODS OF DETECTION AND ANALYSIS
In recent years, advancement in technology resulted in the development of new
devices and new methods of detection and analysis. These methods and these novel
devices enabled researchers to obtain precise and accurate information about the
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