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Summary Cytomixis has been observed in pollen mother cells of Vicia faba. Of all eight sites plant materials were collected and investigated, cytomixis has been noted in six. Four of these sites recorded high percentage of cytomixis, where the two other sites show low concentration of this phenomenon. Cytomixis was observed to occur in forms of cytoplasmic connection and direct fusion. The first type is more frequent than second one. Both types of connections were observed in majority of stages of division. The amount of nuclear material transferred from cell to another was variable from small fragments to the entire complement based on the nature of connection. Abnormalities were observed in all sites investigated. Close relationship is clear between the percentage of this parameter and the percentage of cytomixis. The percentage of pollen fertility is clearly affected by cytomixis and abnormalities. Causes of cytomixis in the present study almost refer to environmental stress and pollution.

Summary The present investigation study the morphological and cytogenetic effects of Calotropis procera extract on Vicia faba L. The control plants being normal while treated ones are significantly affected. Four concentrations (5, 15, 30, 60%) of this extract were applied for 3 duration time. For treated seeds, low doses caused increase in mitotic indix (MI) and exhibit stimulatory effect on percentage of germination and plant height. On the other hand high concentratiosn gave rise to substantial reduction in MI, percentage of germination and plant height and all were found dose and time dependent. In contrast, all parameters tested for treated roots were found negatively affected with no exception and found more harmful and effective compared to seed treatment experiment. Various types of mitotic and meiotic abnormalities were observed. Their percentage of these abnormalities was also found dose and time dependent. Stickiness type was found more frequent compared with other types. The extract also affect chromosome association during meiosis. Chromosome pairing, chiasma frequency and pollen fertility were found negatively affected and dose dependent. The present data confirm the use of this extract as insect control at high concentrations is harmful to plants as non-target organism. It also recommend the use of lower concentration (15%), which has a significant affect on insect with very low side effects on plants. Key words Calotropis procera extract, Cytogenetic effects, Vicia faba The use of synthetic chemicals for plant protection and their cytogenetic effects have been well documented (Shehab 1980, Mohammed 1986, Badr et al. 1985, Qureshi et al. 1988. No doubt, that most of synthetic chemical used surround the world resulted in disturbances of environment and lethal on non target organisms e.g., plant, animal etc. For these reasons, it has become necessary to search alternative natural compounds for environmental safety.Extracts of many plants have been tested for the above reasons (El Gammal et al. 1988, Nassar 1995, Nassar et al. 1997, Soliman and El Sherif 1995, Mohammed 1986. Although many studies were carried on the cytogenetic effects of many plant extracts (Kumar and Kumar 1972, Kabarity and Malallah 1980, Adams and Rashad 1984, Abderrhman 1998, Shapira et al. 1989, Li et al. 1995, Abou El Kheir and Abou El Kheir 1992, Omani et al. 1996, El Khodary 1980, and some others are still in need for such investigation.Extract of Calotropis procera (Family Asclepiadaceae) has been used as botanical insect growth inhibitor by Nassar (1995) and Giridhar et al. (1984). The extract shows effective results as insecticide at certain concentrations.The aim of this study is to investigate the effect of different concentrations (5, 15, 30, 60%) of this extract on percentage of germination, plant growth and cytogenetic of Vicia faba as non target organism. Parameters measured were plant height, percentage of germination, mitotic index, aberrations and mitotic behaviour.

Several studies have investigated the association of different HLA antigens with multiple sclerosis (MS). However, only few studies have considered the association of high‐resolution HLA type and MS with none yet from Saudi Arabia. The aim of this study was to investigate the association of HLA class II alleles with MS in the Saudi population. We used next‐generation sequencing to investigate HLA association with MS. This study was conducted at King Abdulaziz Medical City in Riyadh, Saudi Arabia. We found that several HLA‐DRB1 and DQB1 alleles were associated with MS. These alleles included HLA‐DRB1*15:01 (odds ratio [OR]: 3.01; 95%, confidence interval [CI]: 1.68‐5.54; P = .0001), HLA‐DQB1*02:01 (OR: 1.76; 95% CI: 1.20‐2.58; P = .0022), HLA‐DQB1*06:02 (OR: 3.52; 95% CI: 1.87‐6.86; P < .0001), and HLA‐DQB1*06:03 (OR: 2.42; 95% CI: 1.16‐5.25; P = 0.01). Interestingly, HLA‐DRB1*15:01 was associated with increased risk of previous relapses. In addition, HLA‐DRB1*15:01 and HLA‐DQB1*06:02 were found to be associated with lower vitamin D levels. This study provides insights on the association of different HLA alleles with clinical characteristics and outcome of MS among Saudis. These insights can have future implications for the clinical management of MS based on the patient genetic profile.

The present study investigates the allelopathic effects of Stratiotes aloides on the growth and antioxidative biomarkers of epiphytic and planktonic toxic cyanobacteria in a batch experiment over a 15-day exposure to different concentrations of aqueous acetone extract of this macrophyte. The results showed that epiphytic and planktonic species of cyanobacteria showed differential responses to the allelopathic activity of this macrophyte. S. aloides extract reduced the growth, alkaline phosphatase activity (APA) and toxin production of the planktonic cyanobacterium, Anabaena variabilis, with an increase in lipid peroxidation, glutathione and activities of antioxidative enzymes of this cyanobacterium. Conversely, this extract did not affect the growth and increased the toxin production in epiphytic cyanobacteria, with no significant effect on lipid peroixdation or the activities of APA and antioxidative enzymes of these species. This study is the first to suggest that the macrophyte S. aloides supports the growth and toxin production of its epiphytic cyanobacteria.

This study reports for the first time the presence of Anabaenopsis arnoldi blooms in Saudi freshwaters. This species has been investigated with high cell densities (3.8 x 10(3)-264 x 10(3) cells mL(-1)) during June-November 2007 in Tendaha Lake, one of the major freshwater sources in Saudi Arabia. High temperature and conductivity, and a high concentration of phosphate, and low nitrate concentrations may have contributed to the formation of these blooms. The blooms were found to produce microcystins (MCYSTs) at concentrations up to 364 microg g(-1) dry weight as detected by an enzyme-linked immunosorbent assay. MCYSTs were also detected in the raw and treated water of the lake at concentrations (1.6-8.3 and 0.33-1.6 microg L(-1), respectively) exceeding the World Health Organization guideline level of 1 microg L(-1) for these toxins. HPLC analysis revealed that the extracts of A. arnoldi blooms contained MCYST-RR, -YR and two unidentified MCYSTs, but a pure culture of A. arnoldi isolated from Tendaha Lake during the present study produced MCYST-RR and -YR only. This is the first study to report MCYST production by A. arnoldi. Therefore, this cyanobacterium should be taken into consideration during monitoring of toxic cyanobacterial blooms in drinking and recreational water sources in the world, particularly arid and semi-arid countries including Saudi Arabia.

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