Effects of wastewater application on saturated hydraulic conductivity of different soil textures

As metropolitan areas expand, the municipal and industrial uses of freshwater increase. Therefore, water resources for irrigation become limited and wastewater reuse for irrigation becomes a good alternative. For this purpose, the effects of suspended solids in wastewater on the soil physical properties, i.e., saturated hydraulic conductivity, K_s, have to be considered. The objectives of this research were to study the effects of applying freshwater and differently treated wastewater on K_s in the surface and subsurface layers of sandy‐loam, loam, and clay‐loam soils. This effect was studied by investigating the ratio of K_s for wastewater to K_s for fresh water in soil surface as K_r1 and in soil subsurface as K_r2. The results showed that the application of freshwater did not reduce the K_r1 considerably. However, the reduction in K_r1 mainly occurred in soil depth of 0–50 mm due to the application of wastewater. This effect is more pronounced in clay‐loam soil than in loam and sandy‐loam soils. It is concluded that application of wastewater with TSS (total suspended solid) of ≥ 40 mg L^–1 resulted in K_r1 reduction of >50% in different soil textures. However, the K_r2 reduction at soil depth of 100–300 mm is not considerable by application of wastewater for different soil textures. Further, it is concluded that less purified wastewater can be used in light‐texture soils resulting in less reduction in K_r1. Empirical models were developed for predicting the value of K_r1 as a function of amounts of wastewater application and TSS for different soil textures that can be used in management of wastewater application for preventing deterioration of soil hydraulic conductivity.     

NEW MOLYBDENUM-HYPERACCUMULATOR AMONG PLANT SPECIES GROWING ON MOLYBDENUM MINE- A BIOCHEMICAL STUDY ON TOLERANCE MECHANISM AGAINST METAL TOXICITY

The aim of this work was to determine metal accumulation by plants growing on three molybdenum-mine zones and their tolerance strategies. The plants from tailing, extracting and non-contaminated zones were sampled with their corresponding soils. The results show that molybdenum (Mo) and copper (Cu) were at toxic levels in soils and their levels varied in 44 collected species from 21 families. Ajuga chamaecistus and Cramb orientalis L. excluded Mo and Cu, respectively. Achilla tenuifollia as Mo-hyperaccumulator with total Mo (1979 mg kg^?1) and then Erodium ciconium with 1308 mg kg^?1 Mo and Conyza Canadensis with 618 mg kg^?1 Cu were moderate metal accumulators. They stored considerable levels of metals in their leaves vacuoles and elevated the levels of phytochelatins, cysteine and glutathione and induced antioxidant enzymes. In conclusion, this study indicated that some collected plants excluded metals. In metal-accumulators, antioxidant enzymes, phytochelatins and sequestration of excess metals were involved in their tolerance mechanism.     

Identification and characterization of bacterial strains associated with diseased oak trees in Northern Iran

Oak decline syndrome is characterized by periodic occurrences of decline and death of oaks over widespread areas. An outbreak of a new emerging disease on oak trees was reported in the Hyrcanian forest of Iran (Mazandaran and Golestan provinces) that showed stem bleeding and canker symptoms. Bacterial isolates were characterized through biochemical and physiological tests, protein electrophoresis, DNA fingerprinting (rep‐PCR, ERIC and BOX primers) and sequencing of 16S rRNA and MLSA (multilocus sequencing analysis) for housekeeping genes (gyrB, infB and atpD). A complex community of the genus Brenneria spp. (Brenneria goodwinii, Brenneria roseae subsp. roseae, Brenneria sp. and Brenneria nigrifluens) and a few isolates in the genus Gibbsiella were identified as major groups involved. Isolate differentiation was more accurate using concatenated partial gene sequences within the main groups. All bacterial isolates showed hypersensitivity reactions (HR) on Pelargonium leaves (Pelargonium × hortorum). Pathogenicity studies of different Brenneria and Gibbsiella strains revealed that they have potential to cause the disease in oak seedlings and devastating oak canker and stem bleeding symptoms in northern Iran. Due to the presence of several potentially pathogenic agent(s) associated with the oak decline, identification of the principal agent(s) is of major interest. To our knowledge, this is the first report of potentially pathogenic bacteria associated with oak bleeding and canker in Iran.     

Phylogenetic background and virulence genes of Escherichia coli isolates from colisepticemic and healthy broiler chickens in Iran

The purposes of this study were to determine the phylogenetic background and the virulence gene profiles of Escherichia coli isolates from colisepticemic and feces of healthy (AFEC) broiler chickens. In this study, 253 E. coli isolates including 141 avian pathogenic E. coli (APEC) and 112 AFEC isolates were examined by PCR. In general, 253 E. coli isolates distributed among group A (51.8%), B1 (15.8%), B2 (8.7%), and D (23.7%). Ten (8.9%) AFEC isolates segregated in to B1 phylo-group and 102 (91.1%) isolates fell into six different phylogenetic subgroups. Distribution of colisepticemic and fecal isolates differed significantly in their assignments to A and B1 phylo-groups. The three most prevalent virulence genes were crl, fimH, and aer in isolates between both groups. The four genetic markers aer, papC, afa, and sfa were detected significantly more often among colisepticemic isolates than in fecal isolates from healthy broilers. The presence of stx ₂ gene in fecal isolates were significantly differs among the colisepticemic isolates. F17 fimbrial family encoding gene and eae gene were detected in APEC and AFEC isolates, respectively. The colisepticemic and fecal isolates possessed the virulence genes were detected in all of the four phylogenetic groups. Several combination patterns of the virulence genes were detected in APEC and AFEC isolates. In colisepticemic isolates the combination of aer, crl, and fimH genes was the most prevalent pattern. None of the examined isolates harbored the cdt, cnf1, ipaH, and stx ₁ virulence gene sequences.     

Evaluation of genetic relationships among Iranian pistachios using microsatellite markers developed from Pistacia khinjuk Stocks

To evaluate the genetic relationships among wild and cultivated Pistacia species grown in Iran and the analysis of genetic variation among Iranian pistachio genotypes, two DNA libraries enriched for dinucleotide (AG)_n and trinucleotide (ATG)_n microsatellite motifs were developed from Pistacia khinjuk genome. Following screening of clones by colony PCR technique, 44 clones were sequenced and 27 pairs of primers designed from flanking regions of the repeats. The examination of primer pairs, designed from P. khinjuk sequences, showed successful cross-species amplification within the genus Pistacia. A dendrogram constructed on the basis of the Minimum Evolution clustering algorithm revealed that Pistacia vera has closer relationships with P. khinjuk, than with Pistacia integerrima, Pistacia palaestina, Pistacia atlantica and Pistacia mutica. The dendrogram further distinguished the wild Sarakhs pistachio from the rest of P. vera genotypes suggesting that the domesticated genotypes of P. vera are evolved from P. vera var. Sarakhs and then this wild genotype likely develops to other local pistachios. Hence, it seems that the wild Sarakhs pistachio plays an important role in evolutionary trend of the edible pistachios in Iran. The results indicated that microsatellites developed in P. khinjuk are distributed in the genome of indigenous pistachio species including P. vera genotypes and therefore they will be useful in characterization of Iranian pistachio genotypes.     

Including 793/B type avian infectious bronchitis vaccine in 1-day-old chicken increased the protection against QX genotype

Tropical Animal Health and Production - Infectious bronchitis virus (IBV) is a highly infectious pathogen, which affects the respiratory tract, reproductive system, and kidney of chickens. Many...     

The effects of ketamine‐midazolam anesthesia on intraocular pressure in clinically normal dogs

Objective To determine the effects of intravenous ketamine‐midazolam anesthesia on intraocular pressure (IOP) in ocular normotensive dogs. Animals Thirteen adult mixed‐breed dogs. Procedures Dogs were randomly assigned to treatment (n = 7) and control (n = 6) groups. Dogs in the treatment group received intravenous ketamine 15 mg/kg and midazolam 0.2 mg/kg and dogs in the control group received intravenous saline. The time of intravenous drug injection was recorded (T₀). Measurements of IOP were then repeated 5 min (T₅) and 20 min (T₂₀) following the intravenous administration of ketamine‐midazolam combination and saline in both groups. Results Measurements showed normal IOP values in both groups. The mean ± SD baseline IOP values for treatment and control groups were 13.00 ± 1.47 and 10.33 ± 2.20, respectively. For baseline IOP values, there was no significant difference between treatment and control groups (P = 0.162). In the treatment group, the subsequent post‐treatment mean ± SD values were 15.64 ± 2.17 (5 min), and 14.92 ± 1.98 (20 min). There was no evidence of statistical difference between baseline values and post‐treatment values after treatment with ketamine‐midazolam (P₅ = 0.139; P₂₀ = 0.442). In control eyes, the mean ± SD values at 5 and 20 min were 10.41 ± 2.01 and 10.16 ± 1.69, respectively. There was no significant difference between baseline values and post‐treatment values in control group (P₅ = 1.000; P₂₀ = 1.000). Conclusion Ketamine‐midazolam combination has no clinically significant effect on IOP in the dog.