Fitness benefits of trypsin proteinase inhibitor expression in Nicotiana attenuata are greater than their costs when plants are attacked.

Background

The commonly invoked cost-benefit paradigm, central to most of functional biology, explains why one phenotype cannot be optimally fit in all environments; yet it is rarely tested. Trypsin proteinase inhibitors (TPIs) expression in Nicotiana attenuata is known to decrease plant fitness when plants compete with unattacked conspecifics that do not produce TPIs and also to decrease the performance of attacking herbivores.

Results

In order to determine whether the putative benefits of TPI production outweigh its cost, we transformed N. attenuata to silence endogenous TPI production or restore it in a natural mutant that was unable to produce TPIs. We compared the lifetime seed production of N. attenuata genotypes of the same genetic background with low or no TPI to that of genotypes with high TPI levels on which M. sexta larvae were allowed to feed freely. Unattacked low TPI-producing genotypes produced more seed capsules than did plants with high TPI levels. Caterpillar attack reduced seed capsule production in all genotypes and reversed the pattern of seed capsule production among genotypes. M. sexta larvae attacking genotypes with high TPI activity consumed more TPI, less protein, and move later to the young leaves. Larval masses were negatively correlated (R² = 0.56) with seed capsule production per plant.

Conclusions

Our results demonstrate that the fitness benefits of TPI production outweigh their costs in greenhouse conditions, when plants are attacked and that despite the ongoing evolutionary interactions between plant and herbivore, TPI-mediated decreases in M. sexta performance translates into a fitness benefit for the plant.     

Transcriptomic analysis of changes in Citrus × microcarpa gene expression post Xanthomonas citri subsp. citri infection

European Journal of Plant Pathology - Citrus canker (CC) is an economically important bacterial disease caused by Xanthomonas citri subsp. citri (Xcc). There is variability in resistance to CC...     

Characterization of a monoclonal antibody which detects luteinizing hormone from diverse mammalian species

The present study describes the development and characterization of a monoclonal antibody (518B7) generated against bovine LH (bLH). Although 518B7 was extremely specific for LH, very low species specificity was observed. A RIA using this antibody and radioiodinated equine LH (eLH) showed good sensitivity for all mammalian LH preparations tested, with the exception of human LH (15%, relative to the eLH reference standard). Activities of most mammalian LH's ranged between approximately 50-200%. Much less activity was detected with reptilian LH (less than 1.5%). Amphibian and avian LH fractions were essentially inactive. The reactivities of LH alpha and beta subunits from a variety of mammals clearly showed that the antibody reacts with the beta subunit. Sensitive RIAs were also developed utilizing 125I-bovine and 125I-rat LH. Interestingly, all hormone preparations which showed sufficient reactivity for statistical analysis within the dose ranges used in the present study (0.01-1000 ng/tube) produced a displacement curve parallel to the reference standard. We have also validated the use of 518B7 in detecting LH in serum. Parallel dilution curves relative to purified LH reference standards were observed with equine and bovine serum samples and equine pituitary extract. High (average 94%) recoveries were also seen with bovine serum with known amounts of exogenously added bLH. Similar patterns of LH secretion were detected with a RIA based upon 125I-bLH and 518B7 and a previously described polyclonal antibody-based RIA in bovine serum samples during estrus. Thus, a monoclonal antibody for LH has been produced which can be used to develop sensitive and specific RIAs in many different mammalian species.(ABSTRACT TRUNCATED AT 250 WORDS)     

Strategies for agricultural development in the Fayoum area,Egypt

With the present regime of irrigation supplies to the Fayoum province of Egypt, there is no real problem regarding the increase in water levels of Lake Qaroun which is the major recipient of drainage water. Future developments should therefore concentrate on solving the problem of peak supplies for agricultural use. It has been proposed to remedy the shortage caused by further agricultural developments by increasing the system capacity by 20%. There is, however, an alternative approach which requires no engineering work; this is to change the cropping pattern by introducing rotations which reduce peak water requirements.A simplified water balance based on available data is prepared in order to acquire a better understanding of the whole situation and to set up a strategy for future agricultural development.The developed strategy takes into account the limitations imposed by the closed system of the Fayoum basin such as the irrigation efficiency, the Lake Qaroun optimum water level, land reclamation possibilities, Wadi Rayan drainage surplus, and salt concentrations in Lake Qaroun.     

Bile acid concentrations in the diagnosis of hepatobiliary disease in the cat

The clinical usefulness of measuring serum bile acid concentrations as a diagnostic test for hepatobiliary disease was examined in 80 cats that were suspected of having hepatic disease. Serum values of total bilirubin, alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate transaminase (AST) also were measured. Fasting serum bile acid values were determined by use of solid-phase radioimmunoassay for total conjugated bile acids or by a direct enzymatic spectrophotometric method. A definitive diagnosis was established by histologic examination of the liver, and on the basis of these findings, cats were assigned to groups (1 to 8, respectively) including: extrahepatic bile duct obstruction, hepatic lipidosis, cirrhosis, intrahepatic cholestasis (cholangiohepatitis, cholangitis), neoplasia, hepatic necrosis, portosystemic vascular anomalies, and miscellaneous. Cats in group 8 had no morphologic evidence of hepatobiliary disease or had hepatic lesions that were mild. Test efficacy of fasting serum bile acids, total bilirubin, ALP, ALT, and AST were expressed by use of 4 indices: sensitivity, specificity, positive predictive value, and negative predictive value. The diagnostic efficacy of fasting serum bile acids was examined alone and in combinations with the other tests. There was wide overlapping of values of fasting serum bile acids, total bilirubin, ALP, ALT, and AST among cats in groups 1 to 7. The specificity of fasting serum bile acids for the diagnosis of hepatic disease exceeded 90% at values greater than or equal to 5 mumol/L and reached 100% at greater than or equal to 15 mumol/L.(ABSTRACT TRUNCATED AT 250 WORDS)     

Concurrent infection with ranavirus, Batrachochytrium dendrobatidis, and Aeromonas in a captive anuran colony

Four species (Dendrobates auratus, Phyllobates terribilis, Pyxicephalus adspersus, and Rhacophorus dennysi) of captive anurans with a clinical history of lethargy and inappetence were found dead and were submitted for necropsy. Gross lesions included irregular patches of sloughed skin and rare dermal ulcerations. Histologic findings included epidermal proliferation that was most pronounced on the digits and that included intracytoplasmic chytrid organisms. Bacteria were often associated with the epidermal lesions. Intracytoplasmic inclusion bodies were observed in hepatocytes. Real-time polymerase chain reaction yielded positive results for both Ranavirus and Batrachochytrium dendrobatidis (Bd). Bacterial culture of internal organs yielded Aeromonas hydrophila. This is the first report of concurrent infections in anurans by Ranavirus and Bd and A. hydrophila.     

Rabies in a puppy imported from India to the USA, March 2007

In March 2007, a puppy that was recently imported from India into the United States was found to be positive for rabies by the Alaska Department of Health and Social Services. This case report highlights several important public health issues. First, recognizing that humans and animals are part of a global community with frequent travel and translocation, the risks of disease introduction, particularly with sub-clinical or incubating animals, are real and present. Animal-importation regulations, policies and practices are intended to minimize these risks and should be routinely evaluated and updated as needed in response to occurrences such as detailed in this communication. Second, veterinarians play key roles in safeguarding the public's health with regard to monitoring the movement of animals and diagnosing zoonoses. Third, investigating rabies cases that involve multiple jurisdictions are labour-intensive and require significant resources to ensure that all potentially exposed persons are identified and receive the appropriate rabies post-exposure prophylaxis.     

Evaluation of the effect of mesotherapy in the management of back pain in police working dog

Objective

To evaluate the feasibility and effectiveness of mesotherapy in dogs compared with a positive control group.