Leucine aminopeptidase: an inducible component of the defense response in Lycopersicon esculentum (tomato).

A leucine aminopeptidase (EC 3.4.11.1) cDNA clone (DR57) that was induced in response to Pseudomonas syringae pv. tomato (P.s. tomato) infection was isolated using a subtractive hybridization-enriched cDNA probe. Genomic DNA blot analysis showed that the tomato genome had two leucine aminopeptidase genes. The levels of DR57 mRNAs after P.s. tomato infection and mechanical wounding were determined in two inbred tomato lines that exhibit susceptibility and resistance to P.s. tomato. DR57 mRNAs were detected 12 hours after infection and 4 hours after wounding. Furthermore, DR57 mRNAs were systemically induced in response to wounding. DR57 mRNAs were induced in leaves after Spodoptera littoralis feeding but were not detected in detached leaf controls. Possible roles for the DR57 leucine aminopeptidase in the defense reactions are discussed.     

Regulation of gene expression by ethylene during Lycopersicon esculentum (tomato) fruit development.

We have investigated the regulation of gene expression by the plant hormone ethylene by cloning mRNAs that accumulate in unripe tomato fruit (Lycopersicon esculentum) exposed to exogenous ethylene. The response to exogenous ethylene is rapid; within 30-120 min we detect an increase in the cloned mRNA concentrations. DNA sequence analysis indicates that one of the ethylene-inducible genes is related to a gene encoding wound-inducible proteinase inhibitor I. We have measured ethylene production during fruit development and detect low basal levels in unripe fruit and much higher levels in ripening fruit. Blot hybridization experiments show that expression of the cloned genes is developmentally regulated by ethylene during fruit ripening: the mRNAs produced by these genes are more abundant in ripe fruit than in unripe fruit, and this mRNA accumulation is repressed by a competitive inhibitor of ethylene action, norbornadiene. However, during fruit development some of the cloned mRNAs begin to accumulate when ethylene production is at a basal level, whereas other mRNAs begin to accumulate later when the endogenous ethylene concentration increases, suggesting that gene expression during fruit development can be activated by ethylene in two ways. In some cases gene expression is primarily activated by an increase in sensitivity to basal ethylene levels, whereas in other cases it may be regulated by an increase in ethylene concentration.     

Oral allergy syndrome (pollen-food allergy syndrome).

A case of Oral Allergy syndrome or Pollen-Food Allergy Syndrome is briefly discussed. The clinical characteristics, diagnosis, pathogenesis, and management of this syndrome are discussed followed by clinical pearls and pitfalls for the practicing allergist. Symptoms generally occur with the ingestion of raw fruits/vegetables and nuts; cooked foods are not a problem. Symptoms are caused by a heat-labile protein in fruits, vegetables, and nuts that cross-reacts with proteins in aeroallergens. Cross-reactive proteins share homologous epitopes, and several groups with similar homologous proteins have been identified; many of these groups are referred to as pathogenesis-related proteins.     

Meiosis in sesquidiploid hybrids of Lycopersicon esculentum and Solanum lycopersicoides

We have synthesized diploid hybrids between Lycopersicon esculentum and Solanum lycopersicoides and have converted them to allotetraploids. Two sesquidiploids, having two complements of the former parent and one of the latter, have been obtained by backcrossing the former parent with the alloploid. In meiosis of the sesquidiploid the L. esculentum chromosomes exhibit strong preferential pairing, consistently forming 12 bivalents, whereas the S. lycopersicoides chromosomes remain unpaired. This chromosomal comportment conforms with expectations based on meiosis of the 2x and 4x hybrids. Condensation of the S. lycopersicoides univalents is retarded in early diakinesis but their development appears normal at later stages. Presumably as a consequence of the orderly behavior of the L. esculentum bivalents and consequent contribution to each gamete, fertility of the sesquidiploids is higher than in L. esculentum autotriploids. The normally strict self-incompatibility is somewhat relaxed in the sesquidiploids. Extra S. lycopersicoides chromosomes can be transmitted from the sesquidiploid as pistillate parent, and the aneuploid progeny are viable. Establishment of alien addition races and their utilization to transmit desired genes from S. lycopersicoides to L. esculentum are anticipated.     

Evidence for selection as a mechanism in the concerted evolution of Lycopersicon esculentum (tomato) genes encoding the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase.

The nuclear gene sequences encoding RBCS, the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) from several plants show extensive interspecific divergence but little intraspecific divergence, suggesting that these genes are evolving in concert within a genome. In this study, the nucleotide sequences of two tomato (Lycopersicon esculentum) RBCS genes and a cDNA clone containing the entire coding region of a third tomato RBCS gene were determined. The three genes, designated Rbcs-1, Rbcs-2A, and Rbcs-3A, each belong to a different one of the three RBCS loci in the tomato genome. The nucleotide sequence of Rbcs-1 differs from that of Rbcs-2A and Rbcs-3A by 13.9% and 13.1%, respectively. Rbcs-2A and Rbcs-3A differ from each other by 10.7%. A recently published RBCS gene sequence from tobacco (Nicotiana tabacum) [Mazur, B. J. & Chui, C.-F. (1985) Nucleic Acids Res. 13, 2373-2386] differs by 10.6% and 11.3% from Rbcs-2A and Rbcs-3A, respectively, and by 15.0% from Rbcs-1. Thus the tobacco gene seems to be phylogenetically as closely related to the tomato genes Rbcs-2A and Rbcs-3A as the latter two are to each other, and more closely related to them than Rbcs-1 is. However, the mature part of the polypeptide encoded by the tobacco RBCS gene differs by five and six amino acids from the corresponding region in the polypeptides encoded by Rbcs-2A and Rbcs-3A, respectively, while these two tomato RBCS polypeptides differ from each other in the mature part by a single amino acid. Rbcs-1, whose nucleotide sequence shows higher divergence from both the tobacco RBCS gene and Rbcs-2A and Rbcs-3A, encodes a polypeptide whose mature part differs by eight amino acids from the corresponding region in the tobacco polypeptide but only by three and four amino acids from the corresponding regions of Rbcs-2A- and Rbcs-3A-encoded polypeptides, respectively. Thus, it appears that in the tomato selection has maintained near uniformity of the coding information in the portion of the RBCS genes encoding the mature polypeptides.     

Sexual hybridization of Lycopersicon esculentum and Solanum rickii by means of a sesquidiploid bridging hybrid

A sesquidiploid hybrid having two genomes of Lycopersicon esculentum and one of Solanum lycopersicoides served as a pistillate bridging parent in crosses with Solanum rickii to produce L. esculentum x S. rickii hybrid progeny. Of the four progeny obtained, one (GH2754) was diploid and three were aneuploid with extra S. lycopersicoides chromosomes. The hybrids had morphological features of both parents, but attributes of the wild parent dominated. The hybrid nature of the four progeny was confirmed by isozyme, restriction fragment length polymorphism, and cytological analyses. A mean of 9.15 bivalents was observed in pollen mother cells of GH2754. A high level of pollen abortion was seen in all hybrids. Crosses of the hybrids with staminate S. rickii yielded one backcross individual, revealing a very low, but certain level of female fertility. Colchicine treatment of GH2754 generated one promising amphidiploid hybrid, which exhibited strong preferential chromosome pairing (94% of the examined cells had 24 bivalents) and appreciable pollen fertility (43% stainable). Chromosome pairing, isozyme, and restriction fragment length polymorphism data support a very close relationship between the two Solanum spp. and a much greater distance between them and L. esculentum, but the data do not discriminate between them in respect to their distances from the latter. The cytological and molecular observations, previous reports of successful transfer of traits from S. lycopersicoides to L. esculentum, and our hybridization of L. esculentum x S. rickii suggest good prospects for gene transfer from S. rickii to L. esculentum.     

Severe insulin-induced hypoglycemia in the spiny dogfish shark (Squalus acanthias).

The effect of a single intraaortic infusion of mammalian insulin on plasma glucose was studied in the spiny dogfish shark (Squalus acanthias). Insulin was administered, and blood samples were collected, from an indwelling cannula placed in the dorsal aorta via the anterior mesenteric artery. Plasma glucose was estimated by the glucose oxidase method.Control plasma glucose levels were 37.4 ± 2.5 mg% at time-zero, increased gradually to 45.9 ± 4.4 mg% by 4 days after the infusion of the hormone-free carrier solution, and to 58.1 ± 5.5 mg% by Day 6 when sampling was terminated. The time-zero plasma glucose levels of the dogfish that received 0.5 IU/kg body wt insulin were 46.5 ± 3.2 mg%, declined to 10.2 ± 1.3 mg% by 24 hr after the infusion, and then returned to approximately the time-zero levels by Day 4. The initial plasma glycose levels of the animals that received 50 IU/kg body wt insulin were 38.6 ± 2.6 mg%. The levels fell to 2.1 ± 0.6 mg% by Day 3 and then increased slowly to approximately the time-zero levels between Days 13 and 14 after the treatment. The lowest plasma glucose levels in individual dogfish occurred either on Day 2 or 3 and averaged 1.4 ± 0.3 mg%. No convulsions or other symptoms were observed in the insulin-treated animals. The results indicate that both the magnitude and the duration of the hypoglycemia were dependent on the dose of insulin infused. In addition, the observations that the dogfish were able to tolerate the virutal absence of circulating glucose for extended periods suggest that glucose is not an essential source of energy in this species.     

Severe insulin allergy successfully treated with continuous subcutaneous insulin infusion

Cervical necrotizing fasciitis and a descending mediastinal abscess of the neck following acute epiglottitis, life-threatening complications, is reported in a 43-year-old man with DM. The bacterial culture showed Peptostreptococcus anaerobius. The patient recovered after surgical debridement and broad-spectrum antibiotics therapy.     

High alpha-tomatine content in ripe fruit of Andean Lycopersicon esculentum var. cerasiforme: developmental and genetic aspects.

A variant of Lycopersion esculentum var. cerasiforme is described that deviates from the typical form of the entire species, including cultivated tomatoes, in possessing high levels (500-5000 micrograms/g of dry weight) of the steroidal alkaloid alpha-tomatine in its ripe fruits. This biotype is restricted to a tiny enclave in the valley of Río Mayo, Department San Martín, Peru. Among 88 accessions of var. cerasiforme from its present distribution in the Andes, a 90% association was found between high tomatine and bitter flavor; within the Mayo watershed, all samples from the upper drainage had bitterness and high tomatine; the frequency of both traits decreased to low levels toward the lower end. Tomatine therefore probably is the source of bitterness. Throughout L. esculentum tomatine is present at very high concentrations in earliest stages of fruit development, thereafter decreasing rapidly to midperiod, and finally diminishing gradually to near zero at maturity as a result of catabolism to biologically inert compounds, except in the variant described here. High tomatine content does not appear to affect adversely either the natives, among whom the bitter types are popular, or individuals who sampled them in this survey. Genetic determination of high tomatine in ripe fruits is totally recessive and appears to be monogenic with interaction with genes of minor effect. The prevailing pattern of glycoalkaloid synthesis and degradation in development of solanaceous fruits suggests a mechanism to protect against predation prior to ripening but to permit it afterward as a device to promote dispersal. In consideration of the nondegradative nature of the variant, its genetic determination, and very restricted geographic distribution, mutation to this form appears to be a random event of doubtful evolutionary significance.     

Severe haemolysis after percutaneous closure of a ductus arteriosus (arterial duct).

Severe mechanical haemolysis occurred after transcatheter occlusion of a ductus arteriosus (arterial duct) by a Rashkind double umbrella prosthesis. Surgical removal of the device and ligation of the duct were required before haemolysis was abolished.     

Ultrarush immunotherapy in a patient with occupational allergy to bumblebee venom (Bombus terrestris).

Bumblebee venom allergies, though uncommon among the broad public, pose a significant risk in plant industry and scientific occupation. Since a significant IgE cross-reactivity between bumblebee and honeybee venom has been described in several cases and bumblebee venom for immunotherapy has been available only from a few suppliers, SIT with honeybee venom was frequently used for bumblebee venom allergic patients in the past. We present the case of occupational bumblebee allergy in a biologist who developed anaphylactic reactions with subsequent stings. He was lacking cross-reactivity to honeybee venom, therefore we initiated immunotherapy with bumblebee venom extract. Two months after reaching the maintenance dose of 80 microg, the efficacy of the treatment was demonstrated by sting challenge.     

Severe toxicity and lethality in some monkeys following chronic administration of levo-alpha-acetylmethadol (LAAM).

Recurrent episodes of mild to severe opiate-like toxic effects were observed in 3 of 18 monkeys maintained on 2 mg/kg p.o. dose of LAAM on alternate days 3 times a week for up to one year. Despite antagonist administration and artificial respiration, the final toxic reaction in 3 LAAM sensitive monkeys progressed rapidly to cardio-respiratory arrest and death 3, 6, and 12 months after LAAM treatment. The blood chemistry and hematology were not significantly altered during chronic LAAM administration. Necropsy did not reveal any aberrant gross, histological or neuropathological features other than pulmonary edema. Differential rates of formation and elimination of active metabolites of LAAM may play a significant role in this potentially lethal toxicity. These findings may have important clinical implications for LAAM maintenance treatment programs.