A novel DNA extraction and duplex polymerase chain reaction assay for the rapid detection of Prototheca zopfii genotype 2 in milk

Aims: To develop a PCR‐based assay to detect Prototheca zopfii (P. zopfii) and its mastitis‐related subtype (genotype 2) directly from milk samples. Methods and Results: The DNA extraction method herein is based on the lysing properties of chemical agents, mechanical grinding and DNA‐binding properties of silica particles; this method was developed to rapidly extract DNA directly from P. zopfii in bovine milk. Two pairs of primers specific for P. zopfii and genotype 2 were used in the duplex PCR, and a sensitivity test showed that the detection level was 5 × 10² colony‐forming units (CFU) ml^?1 for P. zopfii and 5 × 10³ CFU ml^?1 for genotype 2. Furthermore, a practical survey of 23 milk samples showed that the assay produced results that were in accordance with those obtained by the conventional microbiology method. Conclusions: The DNA extraction method is effective in isolating sufficient quantities of DNA from P. zopfii in milk for PCR analysis. The PCR assay is economical, sensitive and more rapid than the conventional culture method. Significance and Impact of the Study: The assay could be used as an alternative method for the rapid the detection of bovine mastitis resulting from P. zopfii genotype 2.     

Effect of Different Heat Treatments and Disinfectants on the Survival of <Emphasis Type="Italic">Prototheca zopfii</Emphasis>

Bovine mastitis caused by the yeast-like alga Prototheca zopfii represents a serious veterinary problem and may result in heavy economic losses to particular dairy farms. The purpose of this study was to evaluate the survival of 50 isolates of P. zopfii in milk subjected to different heat treatments and the survival of further 106 P. zopfii isolates after exposure to three classes of teat disinfectants: iodine (Dipal), quaternary ammonium compounds (Teat), and dodecylbenzenesulphonic acid (Blu-gard). Of the 50 isolates tested for thermal tolerance, 29 (58%) survived heat treatment at 62°C for 30 s and 13 (26% of all isolates) of those survived after heat treatment at 72°C for 15 s. None of the 106 isolates were able to withstand the in-use concentrations of the three disinfectants tested. The highest disinfectant concentrations that permitted survival of at least one isolate were dilutions: 1:1,000 for Dipal (survival rate of 52.8–57.5%), 1:100 for Teat (88.7–90.6%), and 1:10 for Blu-gard (100%). No differences in the survival rates of P. zopfii were observed with respect to the duration of exposure to disinfectant. The results of this study support the previous findings that P. zopfii may resist high-temperature treatments, including that applied in the high-temperature, short-time (HTST) pasteurization process. The obtained data also demonstrate the efficacy of the three classes of teat disinfectants against P. zopfii, with the efficacy of iodine being most pronounced. The study emphasizes the necessity of using higher temperatures in the pasteurization of raw milk to kill the Prototheca algae, as well as the particular suitability of the iodine for the control procedures of protothecal mastitis.     

Characterization of <Emphasis Type="Italic">Prototheca zopfii</Emphasis> Associated with Outbreak of Bovine Clinical Mastitis in Herd of Beijing,China

Prototheca zopfii (P. zopfii) has become an important cause of bovine mastitis in many countries. In the present study, to better understand the occurrence of one clinical mastitis (CM) outbreak due to P. zopfii, the molecular characterization and resistance patterns of the microalga were described. P. zopfii strains were isolated from 17 of 23 quarters, which suffered CM in the outbreak, and 7 of 46 CM recovered quarters before the outbreak, as well as 2 of 75 environmental samples in the dairy farm. All strains were identified as genotype 2 by genotype-specific PCR analysis. Results of in vitro antimicrobial and antifungal susceptibility tests indicated that these strains were resistant to majority of tested drugs, with the only exception of amphotericin B, nystatin, streptomycin, gentamicin, and amikacin. This is the first report about CM outbreak caused by P. zopfii in China. These data suggest that P. zopfii may represent a serious risk in the studied herd, and this microalga could be an important potential pathogen causing mastitis in dairy herds of Beijing.     

Determination of the effectiveness of UV radiation as a means of disinfection of metalworking fluids

Microbial contamination of metalworking fluids (MWFs) causes biofouling and degradation and is also associated with several health hazards. Development of an effective control method is therefore essential to reduce microbial loading in MWFs. The present study investigated the efficacy and rapidity of UV radiation as a means of disinfection of MWFs under laboratory conditions to determine parameters that could be used to design an in-line UV reactor for enclosed machines. High and low concentrations (10⁴–10⁷ CFU/mL) of three indicator bacteria, Pseudomonas fluorescens, P. oleovorans subsp. lubricantis and Mycobacterium chelonae, were evaluated both as pure cultures and in combinations. The target organisms were irradiated with a high intensity (192 μW/cm², 55 W) UV lamp for different exposure time under both static and mixed conditions. For these Pseudomonas species with high concentrations of cells under static conditions, only a 56 % reduction was observed within 10 min of exposure, whereas under mixed condition, a 99 % reduction was achieved within 2 min of exposure. In contrast only 74 % reduction was observed for M. chelonae. However, with low concentrations of cells under mixed conditions, a 99.99 % and 82 % reduction in viable count was observed for the Pseudomonas sp. and M. chelonae, respectively. Similar results were observed for mixed culture combinations. Based on these observations high intensity UV in combination with mixing could be successfully used as a means of disinfection of MWFs within a short exposure time and the parameters obtained from the study could be implemented to design a plug flow UV reactor.     

Optimal concentration of Beauveria bassiana vectored by bumble bees in relation to pest and bee mortality in greenhouse tomato and sweet pepper

Greenhouse cage trials were conducted to determine the optimal concentration of Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) (BotaniGard 22WP^® formulation) as vectored by the bumble bee, Bombus impatiens (Cresson) (Hymenoptera: Apidae) pollinator for control of greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) on greenhouse tomato, tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae) and green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae) on greenhouse sweet pepper. Three inoculum concentrations of B. bassiana: low, 9 × 10⁹; middle, 6.24 × 10¹⁰; and high, 2 × 10¹¹ conidia g^?1 of inoculum and two controls (one with bees and heat-inactivated inoculum, and the other which contained only the host plants and pest species) were tested in a completely randomized block design. Beauveria bassiana killed 18, 54 and 56% of the adult T. vaporariorum and 33, 70 and 67% of the adult L. lineolaris, respectively, at the low, middle and high concentrations; but no infection from B. bassiana occurred in each of the control treatments. Internal infection rates after surface sterilization of the pest insects were 11, 34 and 35% for adult T. vaporariorum, 29, 54 and 58% for adult L. lineolaris, 22, 34 and 30% for nymphal M. persicae and 17, 29 and 32% for nymphal T. vaporariorum, respectively, at the low, middle and high concentrations. Significantly more bumble bees died at the high concentration of B. bassiana (42–45%) than at the other concentrations (9–15%) and the controls (5–7%). Spores of B. bassiana were collected throughout the plant canopy with the greatest numbers sampled from the top third of the canopy [ca. 1,200 colony forming units (CFU) per cm^?2]. The middle concentration was selected as the optimal concentration because it provided the best pest control with the least impact on the bees.     

Rapid Detection Device for <Emphasis Type="Italic">Salmonella typhi</Emphasis> in Milk,Juice, Water and Calf Serum

A limit of detection of 200 CFU/mL of Salmonella typhi spiked in various sample matrices were achieved in 30 min. The sample matrices were raw/unprocessed milk, commercially available milk, juice from packed bottles, fresh juice from carts, potable water, turbid water and calf serum. The complete protocol comprised of three steps: (a) cell lysis (b) nucleic acid amplification and (c) an in situ optical detection. The cell lysis was carried out using a simple heating based protocol, while the loop-mediated isothermal amplification of DNA was carried out by an in-house designed and fabricated system. The developed system consists of an aluminum block fitted with two cartridge heaters along with a thermocouple. The system was coupled to a light source and spectrometer for a simultaneous in situ detection. Primers specific for STY2879 gene were used to amplify the nucleic acid sequence, isolated from S. typhi cells. The protocol involves 15 min of cell lysis and DNA isolation followed by 15 min for isothermal amplification and simultaneous detection. No cross-reactivity of the primers were observed at 10⁶ CFU/mL of Escherichia coli, Vibrio cholerae, Salmonella typhimurium, Salmonella paratyphi A, Pseudomonas aeruginosa, Bacillus cereus, Lysteria monocytogenes, Clostridium botulinum, Staphylococcus aureus and Salmonella havana. In addition, the system was able to detect S. typhi of 200 CFU/mL in a concoction of 10⁶ CFU/mL of E. coli, 10⁶ CFU/mL of V. cholerae, and 10⁶ CFU/mL of hepatocyte-derived cellular carcinoma HUH7 cells. The proposed rapid diagnostic system shows a promising future in the field of food and medical diagnostics.     

The Effect of Some Natural Essential Oils Against Bovine Mastitis Caused by <Emphasis Type="Italic">Prototheca zopfii</Emphasis> Isolates In Vitro

The aim of the study was to evaluate the effect of essential oils obtained from Thymus vulgaris L., Origanum vulgare L., Origanum majerana L., Mentha × piperita L. and Allium ursinum L. against Prototheca zopfii strains that cause inflammation of the udder (mastitis) in cows. The study was conducted on ten strains derived from milk samples. The microdilution method was used to determine the sensitivity of P. zopfii strains to the studied essential oils, and the disk diffusion method was used to determine the sensitivity to antifungal chemotherapeutics. The plates were incubated for 48 h at 37 °C under aerobic conditions. All strains of algae were sensitive to the essential oils marjoram, thyme and oregano and resistant to mint and garlic oils. MIC values ranged from 0.25 to 1 μl/ml. Marjoram oil demonstrated the greatest activity, and oregano oil the weakest. Among the antifungal agents tested, 90% of strains showed sensitivity to nystatin. One of the tested strains (71/IV) was resistant to all investigated antifungal agents. The tested essential oils are known to have anti-algae activity and can be used as natural agents for prophylaxis in animals, particularly in mastitis-affected cows.     

Prototheca zopfii: Natural,transient, occurrence in pigs and rats

Domestic swine faeces and fresh faeces from trapped barnyard rats were heavily contaminated with Prototheca zopfii, a cause of dairy cow mastitis. When the pigs and rats were maintained on Prototheca-free diets, the transient intestinal population of P. zopfii decreased precipitously and disappeared. When combined with the information that other farm animals excrete P. zopfii, it was concluded that contaminated animal feed may be the source of large numbers of P. zopfii in the farm environment. We found P. zopfii in wet spoiled feed. Rats are logical vectors for contamination of feed.     

Aggregation and Adhesion Activity of Lactobacilli Isolated from Fermented Products In Vitro and In Vivo: a Potential Probiotic Strain

Approximately 25 strains of lactobacilli isolated from different dairy products and fermented vegetables were screened according to their possibility to show the high auto-aggregation and co-aggregation. The strains Lactobacillus helveticus INRA-2010-H11, Lactobacillus rhamnosus INA-5.1, and Lactobacillus acidophilus JM-2012 were determined to have the high auto-aggregation (approximately 73, 46, and 70.5% correspondingly). A high co-aggregation capacity (75.53%) for strains INRA-2010-H11 and JM-2012 was shown. The adhesion degree of INRA-2010-H11 on the surface of buccal epithelial cells was 88.23%. The study of INRA-2010-H11, JM-2012, and both strains’ mixture (1:1) adhesion capacity on the surface of epithelial HeLa cells revealed the adhesion of 1.1 × 10⁶, 6.3 × 10⁴, and 2.3 × 10⁵ CFU, respectively, from starter amount of CFU 10⁷ and 10⁸ for both strains. In vivo experiments of LAB adhesion in gastrointestinal tract of mouse revealed the presence of 2.5 × 10⁹, 1.2 × 10⁹, and 1.5 × 10⁹ CFU of LAB in control and groups of mouse, fed by INRA-2010-H11 and mixture, respectively. Feeding by investigated lactobacilli was suggested to lead to microbiota biodiversity reduction in small intestine and colon and its augmentation in stomach. Thus, INRA-2010-H11 demonstrated a high aggregation and adhesion activity so it has the potential as a good probiotic strain.     

Nontuberculous mycobacteria: an emerging risk in engineered environmental habitats

Nontuberculous mycobacteria (NTM) are microorganisms commonly living in the environment. Nevertheless, most of them are opportunistic pathogens. To verify concentrations of NTM in some man-made habitats, analyses were performed on water and surface samples, and the data were correlated to the global microbiological quality of water. Most of the drinking water samples (98 %) complied with the microbial requirements established by the European Directive 98/83/EC on drinking water when Escherichia coli was considered. Low counts of heterotrophs were also obtained. NTM were isolated from 72 % of the analyzed samples. Tap water from private buildings, schools and hospitals provided positive results for NTM, with comparable densities ranging from 1 to 6?×10² CFU/L. NTM were also found in swimming pool water samples, with concentrations ranging from 29 to 3?×10⁴ CFU/L, as well as in 70 % of the surface sample. The most frequently isolated species were Mycobacterium mucogenicum, M. intracellulare and M. terrae. These yields confirm that no correlation exists between the monitoring controls carried out by law and the occurrence of these bacteria that may represent a potential risk, especially for immunocompromised people and vulnerable groups.     

Mitogen-activated protein kinase-defective Candida albicans is avirulent in a novel model of localized murine candidiasis

Candida albicans strains with a deletion of the mitogen-activated protein kinase CEK1 gene are defective in the yeast to hyphal transition on solid surfaces in vitro. The virulence of a cek1Δ/cek1Δ null mutant strain was compared with its wild-type parent strain (WT) in a novel model of localized candidiasis. The mammary glands of lactating mice (at day 5 postpartum) were infected for 2, 4 and 6 days with 50 μl suspension containing 1×10⁵, 1×10⁶ and 1×10⁷ blastospores before death. Infected and non-infected control glands were evaluated pathologically. All animals infected with cek1Δ/cek1Δ null mutant strains showed no lesions while 65% of animals infected with the WT strain had severe lesions characterized by widespread heterophilic infiltration, necrosis, and abscess formation. As an additional control, animals infected with the disrupted strain complemented with the WT CEK1, on a replicating plasmid, also showed severe pathological changes similar to the WT strain. These results clearly demonstrate that the CEK1 gene codes for a virulence determinant of C. albicans and that the mouse mastitis model is well suited for the discriminative study of the pathogenicity of different C. albicans strains.     

In Vitro Susceptibility of Prototheca to pH and Salt Concentration

Prototheca sp. can assume high economic significance in the dairy industry and pose a potential risk for the public health. We investigated the in vitro susceptibility of Prototheca isolates retrieved from mastitic milk (P. zopfii and P. blaschkeae) to different pH buffers and salt concentrations using a microbroth assay adapted from the Clinical Laboratory Standards Institute guidelines. Different pH buffer solutions ranging from pH 1 to pH 12 and different sodium chloride concentrations, 4.5, 9 and 18%, were tested. P. zopfii strains presented an optimal growth between pH 5 and 9, a complete growth inhibition at pH 3, and limited growth at pH 1 and 12, whereas P. blaschkeae strains showed higher susceptibility to all pH values except for pH 3 where it demonstrated a moderate growth when compared to P. zopfii strains. When salinity was incremented, P. blaschkeae was more resistant than P. zopfii, although a reduction in growth for all strains of Prototheca was observed. This study demonstrated differences in the in vitro susceptibilities of P. zopfii and P. blaschkeae to different pH and salt concentrations and intend to be a contribution on the understanding of some of the physiologic features that can be associated with the survival of these microalgae in the environment.     

A rapid knockdown effect of Penicillium citrinum for control of the mosquito Culex quinquefasciatus in Thailand

Twenty local isolates of entomopathogenic fungi were determined for control of the larvae and adults of Culex quinquefasciatus. In a laboratory experiment, a Penicillium sp. CM-010 caused 100 % mortality of third-instar larvae within 2 h using a conidial suspension of 1 × 10⁶ conidia ml^?1. Its LC₅₀ was 3 × 10⁵ conidia ml^?1, and the lethal time (LT₅₀) was 1.06 h. Cloning and sequencing of its internal transcribed spacer region indicated that this Penicillium species is Penicillium citrinum (100 % identity in 434 bp). Mortality of the adult was highest with Aspergillus flavus CM-011 followed with Metarhizium anisopliae CKM-048 from 1 × 10⁹ conidia ml^?1. P. citrinum CM-010 at 1 × 10⁶ conidia ml^?1 killed 100 % larvae within 2 h while Bacillus thuringiensis var. israelensis at 5 ITU ml^?1 required 24 h. This P. citrinum CM-010 also greatly reduced survival of C. quinquefasciatus larvae in an unreplicated field test. Light and transmission electron micrographs showed that the fungal conidia were ingested by the larvae and deposited in the gut. The metabolite patulin was produced by P. citrinum CM-010 instead of citrinin.     

Plasma discharge and time-dependence of its effect to bacteria

Several types of plasma discharge have been proven to have a capacity for sterilization. Our goal is to introduce new nonthermal plasma pencil. We used it to sterilize different microbial populations with differing ages. We used a plasma discharge of the following characteristics: radio frequency barrier discharger at atmospheric pressure with a working frequency of 13.56 MHz, and the working gas used was argon. We performed 110 tests with the following microbial populations: Pseudomonas aeruginosa, Staphylococcus aureus, Proteus species, and Klebsiella pneumoniae. All populations were inoculated on the previous day and also on the day of our experiment. We made our evaluations the following day and also after 5 days, with all our microbial populations. Eradication of microbial populations is dependent on the plasma discharge exposure time in all cases. With regard to freshly inoculated microbes, we were able to sterilize agar with intensive exposure lasting for 10 s of colonies Pseudomonas, Proteus, and Klebsiella. The most resistant microbe seems to be S. aureus, which survives 5 s of coherent exposure in half of the cases. Using the lightest plasma discharge exposure, we achieved a maximum of 10⁴–10⁵ CFU/mL (colony-forming unit — CFU). Regarding older microbial populations inoculated the day before the experiment, we can only decrease population growth to 10⁵ CFU/mL approximately, but never completely sterilize. The plasma discharge with our characteristics could be used for the sterilization of the aforementioned superficially growing microbes, but does not sufficiently affect deeper layers and thus seems to be a limitation for eradication of the already erupted colonies.     

Site-related and seasonal variation of bioaerosol emission in an indoor wastewater treatment station: level,characteristics of particle size,and microbial structure

The emission of the airborne bacteria and fungi from an indoor wastewater treatment station adopting an integrated oxidation ditch with a vertical circle was investigated. Microbial samples were collected by the six-stage viable Andersen cascade impactor, and the samples were collected in triplicate in each sampling site per season. Culture-based method was applied to determine the concentrations of the airborne bacteria and fungi, while the cloning/sequencing method was used to characterize the genetic structure and community diversity of airborne bacteria. The highest concentrations of airborne bacteria (4155 ± 550 CFU/m³) and fungi (883 ± 150 CFU/m³) were obtained in June (summer). The lowest concentration of bacteria (1458 ± 434 CFU/m³) was determined in January (winter), and the lowest concentration of fungi (169 ± 40 CFU/m³) was found in March (spring), respectively. The particle size distribution analysis showed that most culturable bacteria obtained in all the sampling sites were in the particle size range of 1.1–4.7 µm. Most culturable fungi had particle sizes in the range 1.1–3.3 µm. Microbial population analysis showed that Bacillus sp., Acinetobacter sp., and Lysinibacillus were the main groups obtained in S1. Enterobacter was the dominant group in sampling site S2. Both the concentrations and particle size distribution of the bioaerosols in the enclosed space presented a seasonal and site-related variation. Concentration and richness of microorganisms in bioaerosols in June were higher than in September and January. The particle size distribution varied between the sampling sites, and proportion of large particles was higher in S2 than in S1 because of the settlement of large particles. Pathogenic species, such as Acinetobacter lwoffii, Staphylococcus saprophyticus, and Enterobacter sp., were isolated from the bioaerosols, which could pose serious latent danger to sewage workers’ health.     

Anti-Bacterial Activity of Recombinant Human β-Defensin-3 Secreted in the Milk of Transgenic Goats Produced by Somatic Cell Nuclear Transfer

The present study was conducted to determine whether recombinant human β-defensin-3 (rHBD3) in the milk of transgenic goats has an anti-bacterial activity against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Streptococcus agalactiae (S. agalactiae) that could cause mastitis. A HBD3 mammary-specific expression vector was transfected by electroporation into goat fetal fibroblasts which were used to produce fourteen healthy transgenic goats by somatic cell nuclear transfer. The expression level of rHBD3 in the milk of the six transgenic goats ranged from 98 to 121 µg/ml at 15 days of lactation, and was maintained at 90–111 µg/ml during the following 2 months. Milk samples from transgenic goats showed an obvious inhibitory activity against E. coli, S. aureus and S. agalactiae in vitro. The minimal inhibitory concentrations of rHBD3 in milk against E. coli, S. aureus and S. agalactiae were 9.5–10.5, 21.8–23.0 and 17.3–18.5 µg/mL, respectively, which was similar to those of the HBD3 standard (P>0.05). The in vivo anti-bacterial activities of rHBD3 in milk were examined by intramammary infusion of viable bacterial inoculums. We observed that 9/10 and 8/10 glands of non-transgenic goats infused with S. aureus and E. coli became infected. The mean numbers of viable bacteria went up to 2.9×10³ and 95.4×10³ CFU/ml at 48 h after infusion, respectively; the mean somatic cell counts (SCC) in infected glands reached up to 260.4×10⁵ and 622.2×10⁵ cells/ml, which were significantly higher than the SCC in uninfected goat glands. In contrast, no bacteria was presented in glands of transgenic goats and PBS-infused controls, and the SSC did not significantly change throughout the period. Moreover, the compositions and protein profiles of milk from transgenic and non-transgenic goats were identical. The present study demonstrated that HBD3 were an effective anti-bacterial protein to enhance the mastitis resistance of dairy animals.     

Effects of stationary phase elongation and initial nitrogen and phosphorus concentrations on the growth and lipid-producing potential of Chlorella sp. HQ

Higher lipid production and nutrient removal rates are the pursuing goals for synchronous biodiesel production and wastewater treatment technology. An oleaginous alga Chlorella sp. HQ was tested in five different synthetic water, and it was found to achieve the maximum biomass (0.27 g L^?1) and lipid yield (41.3 mg L^?1) in the synthetic secondary effluent. Next, the effects of the stationary phase elongation and initial nitrogen (N) and phosphorus (P) concentrations were investigated. The results show that the algal characteristics were affected apparently under different N concentrations but not P, which were verified by Logistic and Monod models. At the early stationary phase, the algal biomass, lipid and triacylglycerols (TAGs) yields, and P removal efficiency increased and reached up to 0.19 g L^?1, 46.7 mg L^?1, 14.3 mg L^?1, and 94.3 %, respectively, but N removal efficiency decreased from 86.2 to 26.8 % under different N concentrations. And the largest TAGs yield was only 6.4 mg L^?1 and N removal efficiency was above 71.1 % under different P concentrations. At the late stationary phase, the maximal biomass, lipid and TAGs yields, and P removal efficiencies primarily increased as the initial N and P concentrations increase and climbed up to 0.49 g L^?1, 99.2 mg L^?1, 54.0 mg L^?1, and 100.0 %, respectively. It is concluded that stationary phase elongation is of great importance and the optimal initial N/P ratio should be controlled between 8/1 and 20/1 to serve Chlorella sp. HQ for better biodiesel production and secondary effluent purification.     

Differences of skin morphology in Bos indicus,Bos taurus,and their crossbreds

Cutaneous evaporation is the main avenue by which cattle dissipate heat via the involvement of sweat glands and other skin components. The difference in skin morphology between B. indicus and B. taurus has been recognized, as well as differences in their ability to tolerate heat. The objective of this study was to compare skin morphology between B. indicus, B. taurus, and their crossbreds. Skin samples of Sahiwal (B. indicus) (n?=?10, reddish brown skin) and Holstein Friesian (HF) (B. taurus) (n?=?10, black and white skin) and crossbred of HF75% (n?=?10, black and white skin) and HF87.5 % (n?=?10, black and white skin) were biopsied for histological study, followed by measurement of skin components. The results indicated that breed significantly affected sweat gland morphology. The shape of the sweat gland, as indicated by the ratio of length/diameter, in Sahiwal was baggier in shape compared to HF (5.99 and 9.52) while values for crossbreds were intermediate (7.82, 8.45). The density and volume of sweat glands in Sahiwal (1,058 glands/cm²; 1.60 μ³?×?10^?6) were higher than in HF (920 glands/cm²; 0.51 μ³x10^?6) and crossbreds, both HF 75 % (709 glands/cm²; 0.68 μ³?×?10^?6) and HF 87.5 % (691 glands/cm²; 0.61 μ³?×?10^?6) respectively. However, capillary surface area was greater for HF (2.07 cm²) compared to Sahiwal (1.79 cm²); accordingly, the lower genetic fraction of HF in crossbred cattle showed less capillary surface area (1.83 and 1.9 cm² for HF75% and HF87.5 %) (P?<?0.01). Nerve density was not significantly different between Sahiwal and HF but was higher in the crossbred (P?<?0.01) cattle. Moreover, the effect of skin color (black and white) was evaluated and it was found that there was an interaction (P?<?0.01) between breed and skin color on the skin components. This study reveals that there are differences in skin morphology among B. indicus, B. taurus and their crossbreds, with these differences being more or less related to the genetic fraction of HF. This may imply that capability for cutaneous evaporative heat loss and tolerance to heat in crossbred cattle could be related to skin morphology.     

Particulate matter and bacteria characteristics of the Middle East Dust (MED) storms over Ahvaz,Iran

The Middle East Dust storms have greatly affected the south and west parts of Iran during the last decade. The main purpose of this study was to examine and compare culturable airborne bacteria concentration in particulate matter (PM) during normal, semi-dust, and dust event days in different places and seasons in Ahvaz from November 2011 to May 2012. Sampling was performed every 6 days and on dust event days at different sampling stations. The overall mean concentrations of PM₁₀, PM_2.5, and PM₁ for the entire study period were 598.92, 114.8, and 34.5 μg/m³, respectively. The PM concentrations during the dust event days were much higher than normal and semi-dust event days. The highest mean PM concentrations were observed in March 2011. The low PM_2.5/PM₁₀ ratios indicate that these PM are mostly originating from natural sources such as dust storms. The overall mean concentration of total bacteria during the study period was 620.6 CFU/m³. The greatest bacterial concentrations were observed during dust event days and at areas with high traffic and more human activities compared with normal days and greener areas. The percentage of gram-positive bacteria was significantly higher than that during the study period (89 vs 11 %). During this study, 26 genera of culturable bacteria were identified from all the sampling stations. The most dominant genera in all sampling stations were Streptomyces, Bacillus, Kocuria, Corynebacterium, and Paenibacillus. The results also showed that there were positive correlations between PM and bacterial concentrations during the study period (p < 0.05).     

Abscisic Acid-Induced Starch Accumulation in Bioenergy Crop Duckweed <Emphasis Type="Italic">Spirodela polyrrhiza</Emphasis>

Spirodela polyrrhiza, a fast-growing duckweed with high starch and low lignin content, shows promise as a feedstock for bioenergy. Abscisic acid (ABA) is a biological hormone that controls plant growth and stress response. The effects of different ABA concentrations (0, 1.0 × 10^?5, 1.0 × 10^?4, 1.0 × 10^?3, 1.0 × 10^?2, and 1.0 × 10^?1 mg/L) on duckweed biomass growth, carbon dioxide fixation, formation of photosynthetic pigments (Chlorophyll a (Chla), Chlorophyll b (Chlb), and carotenoids), the activities of soluble starch synthase (SSS) and starch branching enzyme (SBE), and the starch content of biomass were investigated in this study. ABA at concentrations lower than 1.0 × 10^?3 mg/L promoted carbon dioxide fixation, whereas it inhibited carbon dioxide fixation at concentrations over 1.0 × 10^?3 mg/L. ABA enhanced SSS and SBE activities at concentrations lower than 1.0 × 10^?2 mg/L. ABA treatment increased the content of Chla, Chlb, and carotenoids and resulted in the enhancement of starch content. Chla content gradually increased with the increasing concentration of ABA (1.0 × 10^?5 to 1.0 × 10^?2 mg/L). After culturing for 10 days, starch content in 1.0 × 10^?2 mg/L ABA medium reached 35.3% of dry weight (DW), which was the highest level in this study. This suggests that there is a great potential to develop a technology to increase starch accumulation in duckweed which can be used as an alternative to corn, sugarcane, or other food crops as a starch source.