الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 190 |  |  |
| | | from | 190 | | |
Abstract
Due to the damage caused by land sails to field and horticulture crops, they become serious pests in Egypt which studied a lot in the last years.
The survey of land snails in four governorates of Egypt under study resulted in the presence of E. vermiculata; T. pisana; M. obstructa and H. vestalis were recorded on vegetable crops as (Lettuce, Cabbage and squash), they were recorded on field crops as (Egyptian clover), fruit trees (Guava; pear and Navel orange) and were recorded on ornamental plants as (Adhatoda; Sansevvieria; Casuarina; Kafor and Cocos) and that at all districts of governorates under study ; in Behera Governorate at districts (Kafer El-Dawar; Abou-Homos and Abou El- Matamir), in Sharkia at districts (Zagazig; Belbaes and El-Ebrahemia), in Sinai Governorate at districts (Bar-ElAabd and Om-romana ) and in Assuite at districts (El Fath And El-Wasta). But the Monach obstructa was not recorded at districts of Sinai Governorate.
The population density of surveyed land snails are with variable counts on different plants .The land snails, M. cartuisana and M. obsrtucta are found in high density on field crops with counts ranged from (188 to 550) ) snail on Egyptian clover and on were recorded on vegetable crops with count (88 to 415) ) snail , were recorded on cabbage with count, (100 to 300) snail and were recorded on squash vegetables with counts ranged from (23 to 140) snail, while were not recorded on fruit trees and ornamental plants. On the other hand, the two land snails T. pisana and H. vistalis found in high density on fruit trees, guava, with
counts ranged between (88 to 620) snail, were recorded on navel orange with counts (55 to 520) ) snail and were recorded on pear with counts (67 to 612) ) snail.
While the land snail, E.vermiculata found in high population density in ornamental plants. It was recorded On Adhatoda with count (5to 250) ) snail, it was recorded on Sansevieria (5 to 412) ) snail, it was recorded on Caesarian (3 to 200), it was recorded on Kafor (6 to 213) and was recorded on Cocos (32 to 191) snail.
6.2. Molecular biological studies:
We sampled populations of M. obstructa and E. vermiculata from different geographical provinces (Behera; Assuite; Sharkia and Sinai) to examine if these populations of each species are genetically different or not so we studied the mutations in the nuclear 18S rRNA gene. The gene was detected by its primer and amplified by polymerase chain reaction (PCR) for the two reference sequences of NCBI (M. cantiana and E. vermiculata); E. vermiculata of Behera; E. vermiculata of Assuite; E. vermiculata of Sharkia and E.vermiculata of Sinai and three populations of M. obstructa (M. obstructa of Behera; M. obstructa of Assuite and M. obstructa of Sharkia.
The populations of land snails under study show nucleotide composition differnation between them. There are some variations between the nucleotides of each population under study; in populations of E. vrmiculata, the average count of T is (23.8), C (26.6), A (28.5) and G (29.1), whereas the variations in M. obstruct, the average count of T is (24.0), C (26.6), A (21.3) and G (28.0).
The PCR products were separated by agarose gel electrophoresis and visualized under UV lamp by staining them with ethidium bromide. Their molecular weights were measured using molecular size standard marker and then were cut from the gel and cleaned then treated for sequencing.
In addition, the bioinformatics analysis, such as; partial 18S rRNA gene sequence alignment of the four populations of E. vermiculata according to E. vermiculata NCBI proved that there are SNPs between the E. vermiculata in (Sharkia; Assuite; Behera and Sinai) governorates and the E. vermiculata of NCBI.
There were variation in nucleotide frequency percent difference between the four populations; C/T of Behera (1.64), Assuite (1.68), Sharkia (1.24), Sinai (4.1), C/G Behera (1.2), Sharkia (0.41), Sinai (3.73), G/A is Behera (0.82), Sharkia (0.83), Sinai (3.73), T/C of Behera (1.2), Assuite (0.84), Sharkia (1.24), Sinai (3.73), T/G of Behera (0.40), Sinai (2.09), C/A Behera (0.40), Assuite (0.42), Sinai (2.49), G/C of Behera (1.02), Assuite (1.62), Sharkia (1.24), Sinai (4.56), G/T of Behera (1.2), Sharkia (1.24), Sinai (3.73), A/G Behera (0.40), Sharkia (1.65), Sinai (2.49), A/T ratio Sinai is (2.49), T/A ratio in Assuite is (0.84) and Sinai (3.73), A/C in Behera (0.40), Assuite (0.84), Sharkia (1.24), Sinai (1.66), missing A Behera (0.82), Assuite (0.84), Sharkia (0.41), Sinai (0.42), missing G Behera (0.82), Assuite (0.42), Sinai (0.82), missing T in Assuite (0.84), Sharkia (0.84) and Sinai (0.42) , extra C in Sinai (0.82 ) and extra G is (0.42).
There were variation in nucleotide frequency percent differences between the three population of M. obstructa when compared to the reference; C/T in Behera (0.77), Sharkia (0.40), C/G in Behera (0.39),
Assuite (1.2) and Sharkia (0.40), G/A in Behera (0.39) Assuite (0.9) and Sharkia (0.40), T/C Assuite (0.9) and Sharkia (0.40), C/A Behera and Assuite (0.39) and Sharkia (0.40), G/C Behera (1.2) and Assuite (0.39), G/T Behera (0.77) and Assuite (1.6), A/G Behera (0.77), Assuite (0.9) and Sharkia (0.40), A/T in Behera (0.39), Assuite (1.2) and Sharkia (1.97), T/A Behera (1.2), Assuite (0.39) and Sharkia (0.40), A/C Behera (1.55), Assuite (0.39) and Sharkia (0.79).