epithelial disruption together with feeding
cessation and starvation consequently the loss of body weight and high
mortality. The low gut pH i.e., acidic of locust and grasshopper may prevent
the dissolution of the crystalline ?-endotoxin, which is normally dissolved and
activated by a high gut pH (Prior and Greathead, 1989). Nevertheless, it has
been demonstrated that crystals from one B.
thuringiensis strain, dissolved readily in the gut juice of S. gregaria but not in that of L. migratoria, although bacterial
species nature have a very similar gut pH of around 5.3 (Stephan, 1992). This suggests
that other factors, such as reducing conditions or gut enzyme, play important
role in the dissolution process. The gut conditions of alkaline D. maroccanus seem to allow the
dissolution of the ?-endotoxin of B.
thuringiensis strain, and therefore, strain and the host meet the
requirements for insecticidal activity (Quesada-Morage et al., 2001).
al. (2006) suggested that re-establishment an Enterobacter sp. That normally resides in the midgut microbial
community, restore B. thuringiensis mediated
killing and paralysis of the insect. On the other hand the enteric bacteria
alone did not induce mortality in the absence of the B. thuringiensis Cry gene
toxin that permeabilises the gut epithelium allowing their access to the
haemocoel. Inoculated individuals might be due to disruption of epithelium
initially which provided opportunity to enterogastric bacterium to gain access
and multiply in the hemolymph. This also suggests that B. thuringiensis was unable to multiply in the hemolymph but
provided catalytic support to enteric bacteria for the death of locust. Our observation
is in accordance with Broderick et al.
(2006) where they suggested the similar hypothesis.
It was evidenced that hemolymph protein of infected
nymphs reduced initially during nymphal and early adult stages. In later stage
of adult maturation, the protein level increased above the control adult. The effect
of B. thuringiensis on reduction in
haemolyph protein and haemocytes due to water loss has been reported earlier in
S. gregaria (Lee, 1961; Barakat et al., 2002) as well as in L. migratoria (Webley, 1951; Hill and
Stevenson, (1959) reported that gut bacterial
diversity confers prevalence and resistance to invasion of foreign, pathogenic
bacteria in S. gregaria and
determines the impact of invasion resistance on host survival. Serratia marcescens is pathogenic which
cause disease in dissert locusts.
cereus is biocontrol agent have been recognized before the
bacterium was identified, with some account suggesting that B. cereus spore may have already been in
use in ancient Egypt. The bacterium was isolate in 1901 by the Japanese
biologist Shigetane Ishiwatari during an investigation into wilt disease in
silkworm and named it Bacillus sotto. Prior and Greathead, (1989) is observed that the bacterium, B. cereus is pathogenic and
caused the effect on mortality in inoculated locusts increased and weight loss
also evidenced. The low gut pH of locusts and grasshoppers may prevent the
dissolution of the crystalline ?-endotoxin, which is normally dissolved and
activated by a high gut pH. The
?-endotoxin form pores in the membranes of epithelial cells causing disruption
of the insect gut epithelium and ?, ? endotoxin are effective against the fat
body, reproductive organ and other internal tissues. The final cause of insect
death was due to be the spread of Bacillus
cereus, once it gained access to the hemocoel and spread to the all other
internal body parts after epithelial disruption, accompanied by feeding
cessation leading to starvation and small body size. However, the highly potent
crystal toxin is pathogenic only in conjugation with the observation that B. cereus is able to multiply in the
insect haemolymph while entero-bacteria can be multiplied in it, suggested
that, the B. cereus toxin free access
to the more favorable environment of the hemocoel of most of the insect, where
they replicate, leading to septicemia and of the insect death host (Broderick et al., 2006).
Zahran et al, (2011) is reported that the efficiency of six bacterial
strains to kill cotton leaf worm (Spodoptera
littoralis), was isolated from dead spiny cotton bollworm (Earias insulana). The isolated bacterial
strain examined were identified in the genus Bacillus, six species were identified namely; B. anthracis. B. cereus, B. fusiformis, B. pseudomucoides, B. subtilis and
B. thuringiensis. Some other these
bacilli are genetically related, e.g., B.
cereus, B. thuringiensis and B.
anthracis, this observation supported that Bacillus species are present in the insect internal body organ.
cereus affects the developmental stages of the migratory
locust physiologically as well as morphologically. The characteristics of
protein banding patter suggest that number of protein band appeared on the gel
were more as compared to might be due to recovery or immune response of the
individual as well as accumulation of bacterial protein (Zahran et al,. 2001)
The characteristics of
electrophoresis separation technique to protein banding pattern suggests that,
the number of protein band appeared on the gel were less as compared to control
but again repapered at later stages of development i.e., is suggested that
immunoprotein are synthesi. This might be due to recovery of storage protein in
the individuals having more immunity and the insect survived during later