Evaluation of cytological effects of Zn2+ in relation to germination and root growth of Nigella sativa L. and Triticum aestivum L.

The effects of different treatments with zinc sulfate (Zn(2+)) on the cytology and growth of Nigella sativa and Triticum aestivum were investigated. Five concentrations of zinc sulfate ranging from 5 to 25mg/l were applied for 6, 12, 18, and 24h. The treatments reduced the germination percentages of N. sativa seeds and T. aestivum grains and inhibited the root growth of both plants. Concentrations higher than 25mg/l of Zn(2+) applied for 24h were toxic for both plants. The non-lethal concentrations of Zn(2+) showed an inhibitory effect on cell division in root tips of both plants and caused a decrease in their mitotic index values. The reduction in MI in root tips of T. aestivum was more evident than that of N. sativa. All treatments changed the frequency of mitotic phases as compared with the control values. The total percentage of abnormalities in N. saliva was more than that in T. aestivum. Zn(2+) treatments produced a number of mitotic abnormalities in dividing cells in root tips of both plants resulting from its action on the spindle apparatus such as C-metaphases, lagging chromosomes and multipolar anaphases and telophases. Also, Zn(2+) induced vacuolated nuclei and irregular prophases. The induction of chromosomal stickiness and chromosomal aberrations such as bridges and breaks indicates its action on the chromosome. These abnormalities (chromosome breaks and chromosomal bridges at ana-telophases) indicate true clastogenic potential of the ions tested.

The mouse adenovirus type 1 contains an unusual E3 region.

Since the E3 region of human adenoviruses codes for a series of proteins that are probably involved in viral pathogenesis, the nucleotide sequence for a 3.6-kilobase DNA fragment in the corresponding region (map units 77 through 89) of the mouse adenovirus type 1 genome has been determined. Analysis of the sequence revealed that the genes for the fiber and for the precursor to the hexon-associated protein, pVIII, that usually flank the E3 region, are well conserved. However, many of the open reading frames contained in the E3 region of human adenoviruses between the pVIII and the fiber genes were absent from the mouse adenovirus type 1 genome.

Bacterial meningitis in Egypt: analysis of CSF isolates from hospital patients in Cairo, 1977-78.

Bacterial meningitis remains a major cause of mortality and morbidity in many countries of the world despite effective antimicrobial therapy. Studies of the etiology and some laboratory characteristics of bacterial meningitis in Egypt were conducted during 1977-1978. All patients suspected of having bacterial meningitis were studied at the time of admission to the two fever hospitals of Cairo. Direct culture, serological identification of the capsular type, and countercurrent-immunoelectrophoresis of 1627 CSF specimens were done. Of these, 276 had bacteria identified either by culture or Gram stain. Pneumococci were the most common and the serotype distribution was similar to that reported from other parts of Africa; second were meningococci with groups C and B predominating; in third place was Haemophilus influenzae type b which caused the highest mortality and had an unusually young age distribution. There were 77 bacterial isolates (22%), including 11 species, designated as "other" because there was no predominant species. There were many "clear" CSF specimens that were found to contain pneumococci, meningococci or H. influenzae type b, confirming the need for more comprehensive laboratory facilities for accurate diagnosis of the etiology of bacterial meningitis.