Molecular identification of a phytoplasma associated with Russian olive witches’ broom in Iran

Russian olive trees (Elaeagnus angustifolia) showing witches’ broom symptoms typical of phytoplasma infection were observed in the Urmia region of Iran. A phytoplasma named Russian olive witches’ broom phytoplasma (ROWBp-U) was detected from all symptomatic samples by amplification of the 16S rRNA gene and 16S/23S rDNA spacer region using the polymerase chain reaction (PCR) which gave a product of expected length. DNA from symptomless plants used as a negative control yielded no product. The sequence of the 16S rRNA gene and 16S/23S rDNA spacer region of ROWBp-U showed 99% similarity with the homologous genes of members of the aster yellows group. We also detected a phytoplasma in neighboring alfalfa plants (AlWBp-U) showing severe witches’ broom symptoms. An 1107 bp PCR product from the 16S rRNA gene showed 99% homology with the corresponding product in ROWBp-U, suggesting the presence of the same phytoplasma actively vectored in the area. Further observations showed that Russian olive trees with typical ROWB symptoms were present in an orchard near Tehran which is located over 530 km south-east of the original Urmia site. The corresponding sequence of this phytoplasma (ROWBp-T) showed 99% homology to that of the ROWBp-U. A sequence homology study based on the 16S rRNA gene and 16S/23S rDNA spacer region of ROWBp-U and other phytoplasmas showed that ROWBp-U is most closely related to the 16SrI group. To our knowledge, this is the first report of a phytoplasma infection in a member of the Elaeagnaceae.     

早熟无限结荚习性大豆子粒生长特征

大豆产量潜力受到基因型和环境条件的制约。一种基因型的密度、植株分布决定其对太阳辐射、水分和养分的利用,进而高产的形成。当群体生长所需外界要素之一不能满足时,植株间形成竞争。产量的区域间及年际间差异与这种株间竞争关系密切,最终表现为单位面积内一个或多个产量构成因子的差异,如株荚数、荚粒数、或单粒重(籽粒大小)。本研究探讨籽粒大小在调节不同密度、行距条件下产量差异及年际间产量差异的作用。多点试验表明,籽粒大小在不同节位上及不同籽粒数的荚间差异不大。然而在2粒或3粒荚内,荚基部粒比中部及顶部粒小10%,而且子叶细胞体积差异不大。在改变源库、增强光照或遮阴条件下,籽粒大小发生变化。籽粒大小与子叶细胞数相关。籽粒大小是可塑的,但即使底部节位荚较顶部节位提前15~20 d鼓粒,籽粒大小在所有节位间差异不大,所以籽粒大小与子叶细胞数的关系仍值得探讨。     

Occurrence of anti-<Emphasis Type="Italic">Toxoplasma gondii</Emphasis> antibodies in female cattle in south-west of Iran

Toxoplasmosis, caused by Toxoplasma gondii, is a significant disease in livestock and humans. In Iran, studies shows that T. gondii infection in humans is relatively high and prevalence is associated mainly with consumption of undercooked meat or meat products. We have examined 450 serum samples from female cattle distributed over all Ahvaz, the center of Khouzestan province, south-west of Iran. IgG antibodies to T. gondii were assayed by the modified agglutination test using whole tachyzoites of T. gondii, and found in 71 (15.77%) of 450 cattle with titers of 1:25 in 38, 1:50 in 18, 1:100 in 11, 1:200 in three and 1:400 in one. Titers of antibodies were decreased in cattle over 2 years old. These results indicate that T. gondii infection in cattle of Khouzestan is relatively considerable, but not very high and consumption of beef may be a source of infection for humans in south-west of Iran.     

Effects of short-term oral administration of propranolol on tear secretion in clinically normal dogs

This study evaluated the effects of short-term oral administration of propranolol on tear secretion in 15 clinically normal crossbreed dogs. The treatment group (n = 8) received propranolol (2 mg/kg q8h) orally for 7 days. The control group (n = 7) received placebo during the study. Schirmer I tear tests were performed on both eyes 1 d prior to drug administration (T(0)), at 1 (T(1)), 3 (T(3)), and 7 (T(7)) days of treatment. Tear production in dogs, measured by STT, was not significantly reduced in both groups.     

Molecular genotyping and epidemiology of Mycobacterium bovis strains obtained from cattle in Iran

Restriction fragment length polymorphism (RFLP) genotyping was employed to analyze the population genetics of Mycobacterium bovis in Iran. One hundred and twenty-three isolates collected from slaughtered tuberculosis-suspect cattle and one clinically asymptomatic buffalo were subjected to RFLP analysis with probes of the polymorphic GC-rich sequence (PGRS) and the direct repeat sequence (DR) using DNA digested with PvuII and AluI. All these methods detected a large homogeneous population in which only a few isolates had variant genotypes. Only AluI-based RFLPs of both the PGRS and DR sequences were able to clearly differentiate between BCG and field strains of M. bovis. As in previous reports, these findings seem to reflect a recent dispersal of one or a few strains in Iran following the substantial expansion of Holstein-Friesian cattle over the last few decades.     

Soil application of entomopathogenic nematodes suppresses the root-knot nematode Meloidogyne javanica in cucumber

Journal of Plant Diseases and Protection - Cucumber (Cucumis sativus) cultivation in commercial greenhouses occupies an important section of vegetable production in Iran. Root-knot nematode...     

The effect of pH and calcium on copper availability to the springtail Folsomia candida in simplified soil solutions

The effect of pH and calcium on copper bioavailability to the springtail Folsomia candida was determined by assessing uptake kinetics upon copper exposure for 15 days in simplified soil solutions. A slight bioaccumulation of copper was observed in all treatments and controls. The effect of exposure concentration and calcium level on copper accumulation was not significant. Although pH and time slightly but significantly affected copper concentrations in the body, copper uptake rates were not significantly different from zero. This suggests that copper uptake in F. candida exposed to sub-lethal copper concentrations in soil pore water is not affected by pH and calcium.     

Molecular and morphological investigation in Hymenocrater: species delimitation,relationship, divergence time and DNA barcoding

Genetic Resources and Crop Evolution - Hymenocrater comprises of 11 species throught the world. The genus is an Irano-Turanian elements, which has several usages in traditional medicine. Northeast...     

Isolation of Streptococci from milk samples of normal, acute and subclinical mastitis cows and determination of their antibiotic susceptibility patterns

Streptococci are frequently isolated from bovine mastitis in dairy cows with only limited information available on the antimicrobial susceptibility of these organisms. A total of 42 Streptococci isolated from 148 milk samples of normal, sub acute and acute bovine mastitis cases. Overall, 35% of the strains tested were Streptococcus dysgalactiae, Streptococcus agalactiae 26%, Streptococcus uberis 18 and 4% were Enterococcus sp. Differences between the number of isolations in acute and sub acute groups were statistically significant, (p<0.5). The antimicrobial susceptibility for these organisms was determined for the following antimicrobial agents: cephalexine, penicillin, clindamycin, cloxaciline, gentamicin, streptomycin, amoxicillin, tetracycline, kanamycin, oxytetracycline, ampicillin, chloramphenicol and erythromycin. S. agalactiae, S. dysgalactiae, S. uberis and Enterococci demonstrated high level of resistance against streptomycin, penicillin and cloxaciline. Low level of sensitivity to other tested antimicrobials was demonstrated.     

Selectivity of Three Miticides to Spider Mite Predator, （Acari： Phytoseiidae） Under Laboratory Conditions

The predatory mite, Phytoseius plumifer （Canestrini ＆ Fanzago）, is one of the most abundant natural enemies and efficient predator of phytophagous mites in Iran. The miticides hexythiazox （Nisorun, EC 10%）, fenpyroximate （Ortus, SC 5%）, and abamectin （Vertimec, EC 1.8%） were tested in the laboratory for their side effects on P. plumifer. The miticides were applied at the highest field recommended concentration （N） to detached leaves using a Potter Tower to deposit 2 mg spray solution per cm2. Percent predator mortality was evaluated from the protonymph up to the adult stage including the first five days of the oviposition period. Analysis of data showed that the total effect values of hexythiazox were below the lower threshold, and thus it could be considered to be a harmless miticide to P. plumifer. In contrast, the total effects of fenpyroximate and abamectin were found harmful to the predatory mite at the highest field recommended concentrations.