Vol. 8 Issue 1
Ali H. Al-Mousawi and P.E. Richardson
Ultrastructure of Xanthomonas campestris pv. malvacearum Grown in susceptible (Ac 44) and resistant (Im 216) cotton plants was compared with that of the same bacteria grown to late stationary phase in nutrient broth culture. Bacterial cells grown in broth contained many ribosomes throughout the cytoplasm, and DNA strands occupied the central part of the cell. Polyribosomes and osmiophilic vacuoles were present only in actively growing bacteria.
In susceptible cotton plants, X. campestris pv. malvacearum had similar structural features to broth-grown bacteria. During late stages of disease, capsular coating material developed on those bacteria embedded in a fibrillar material in host intercellular spaces. In resistant plants, bacterial cells developed similar cytoplasmic structure with no polyribosomes or osmiophilic vacuoles and resembled bacteria in late disease stages of susceptible plants.
Bacteria fixed at late stationary phase in broth differed from those fixed from leaf material in late disease stages. Broth grown bacteria exhibited dissolution, coalescence of ribosomes and nuclear material, as well as vacuole development within intact cell membranes. In late diseased cotton leaves, bacterial calls showed cell membrane degeneration
A.I.I. Abdel-Hafez, M.B. Mazen and A.A. Galal
122 species belonging to 36 genera were collected from 100 soil samples on glucose- Czapek's agar at 28°C. The most frequent species were Aspergillus niger, A. fumigatus and A. terreus followed by A. flavus, A. nidulans, Penicillium chrysogenum and Fusarium solani.
On cellulose-Czapek's agar at 28°C, 30 genera and 102 species were isolated. The most frequent species were A. fumigatus, A. terreus and A. niger followed by A. nidulans, A. flavus var. columnaris, A. flavus, P. chrysogenum, F. solani, Chaetomium globosum, Stachybotrys atra and Botryotrichum atrogriseum.
Nasser A. Al-Asgah, Fathi M. Diab and Mohammed S. Al-Khalifa
Adult Haemaphysalis (Herpetobia) sulcata (Canestrini & Fanzago, 1878) parasitize goats and sheep at the Al-Sarawat Mountain range of western Saudi Arabia, where the immature stages infest Agama lizards. The infestation of both goats and sheep by H. (H.) sulcata was seasonal and occurred only during the period from October through April, with a peak in December and January. The tick can complete one or, possibly two, intergrading generations per annum and its population seems to be affected by marked seasonal environmental changes. Haemaphysalis (H.) sulcata in the Al-Sarawat Mountains coexists with Hyalomma arabica, Boophilus kohlsi and Rhipicephalus turanicus. Elsewhere in the Kingdom, goats and sheep are parasitized chiefly by R. turanicus, H. impeltatum, H. anatolicum and B. kohlsi
Abdullah M. Al-Bekairi
The effect of an imported chewing gum on the male and female reproductive systems of Swiss albino mice was evaluated. The chewing gum was administered both in drinking water and food at a pooled dose of 2 g/kg/day for a period of 8 weeks. The results revealed that the imported gum lacks the potential to induce spermatotoxicity, sterility or embryonic loss for the exposure period used. The observations on the female reproductive system indicated insignificant changes in fertility and post-implantation loss. However, the total and pre-implantation embryo losses in the treated females increased as compared with the control group. The estrogenic activity of the gum was evaluated using gum extract, suspended in corn oil, and administered (i.p.) in a dose of 250 mg/kg/day for 3 days. The results showed an increase in the uterine weight in experimental groups when compared with control groups. However, a statistically significant activity was evident only in the strawberry-fllavoured gum. It is possible that the chewing gum contained some flavouring components with potential estrogenic activity that interfere with the hormonal status and hence the process of ovulation.
Abdel-Ghani N. Khalil
The standing crop of Cystoseira myrica along the Jeddah coast was assessed. Two peaks were found during the year; a major one was observed in May and a minor in October. Spring proved to be the more productive season. The biomass values ranged from 0.78 kg/m2 at Obhur in January to 3.9 kg/m2 at Hatibah in May. The monthly average of the biomass in the whole area of study was estimated as 1.8 kg/m2. The biomass of Cystoseira myrica at North Jeddah is about three times of that observed at south Jeddah.
No sharp fluctuation in the seasonal values of biomass of Cystoseira myrica was noticed in Jeddah area, as a result of the relative stability of the environmental factors.
The productivity of Cystoseira myrica along the Jeddah coast is in general low, relative to that of Cystoseira spp. in the Mediterranean, Adriatic Sea and Black Sea.
Sixty species belonging to the main three classes of algae were found among the associations of Cystoseira myrica
Z.F. Al-Jalili and S.A. Magid
Random sample of 68 ram lambs weaned at 4 months were used in this study. Lambs were fattened for 3 months on concentrates of 13% crude protein, while alfalfa and forages were offered ad lib. All lambs were slaughtered at 7 months of age and divided according to their live weight to three groups, i.e. less than 30 kgs, from 30 to less than 35 kg, and 35 kg and higher. Number of lambs within these groups were 22, 28 and 18, respectively. Measures taken at slaughter were weights of hot carcass, cold carcass, head, legs, skin, empty digestive tract, digestive tract contents, mesenteric fat, kidney fat and organs (liver, lungs, hear, kidney) and testis.
Results indicated that lambs weighted 35 kg and higher gave higher (p<0.05) killing-out percentages than groups of lighter weights. While, the latter groups gave higher (p<0.05) percentages of secondary body portions and slaughter byproducts. It was also found that live weight at slaughter had significant positive (p<0.01) correlation with killing-out percentage and with most secondary body portions. Results of this study also revealed an increase in killing-out percentage on live weight basis with the increase in live weight at slaughter (39.23, 43.41, and 46.24% for the three weight groups, respectively). These results suggest that slaughtering Awassi lambs with a live body weight of not less than 35 kg improves carcass weight which leads to higher production of meat and reduced slaughter byproducts and secondary body portions of low economic return