Transgenic Citrange troyer rootstocks overexpressing antimicrobial potato Snakin-1 show reduced citrus canker disease symptoms.

Citrus canker is a major disease caused by Xanthomonas citri pv. citri. Snakin-1 is an antimicrobial peptide, which was previously shown to be effective against different bacterial and fungal diseases in potato, wheat and lettuce when expressed in transgenic plants. We generated transgenic Citrange Troyer citrus rootstocks constitutively expressing this peptide and 5 different transgenic lines were challenged against virulent X. citri isolates. Challenge assays conducted in vitro using detached leaves and in planta by infiltration revealed a significant reduction of the number and size of canker lesions in some of the transgenic lines.

Status of low-energy accelerator-based BNCT worldwide and in Argentina.

Existing and active low-energy Accelerator-Based BNCT programs worldwide will be reviewed and compared. In particular, the program in Argentina will be discussed which consists of the development of an Electro-Static-Quadrupole (ESQ) Accelerator-Based treatment facility. The facility is conceived to operate with the deuteron-induced reactions 9Be(d,n)10B and 13C(d,n)14N at 1.45 MeV deuteron energy, as neutron sources. Neutron production target development status is specified. The present status of the construction of the new accelerator development laboratory and future BNCT centre is shown.

Modulation of host plant immunity by Tobamovirus proteins.

BACKGROUND: To establish successful infection, plant viruses produce profound alterations of host physiology, disturbing unrelated endogenous processes and contributing to the development of disease. In tobamoviruses, emerging evidence suggests that viral-encoded proteins display a great variety of functions beyond the canonical roles required for virus structure and replication. Among these, their modulation of host immunity appears to be relevant in infection progression. SCOPE: In this review, some recently described effects on host plant physiology of Tobacco mosaic virus (TMV)-encoded proteins, namely replicase, movement protein (MP) and coat protein (CP), are summarized. The discussion is focused on the effects of each viral component on the modulation of host defense responses, through mechanisms involving hormonal imbalance, innate immunity modulation and antiviral RNA silencing. These effects are described taking into consideration the differential spatial distribution and temporality of viral proteins during the dynamic process of replication and spread of the virus. CONCLUSION: In discussion of these mechanisms, it is shown that both individual and combined effects of viral-encoded proteins contribute to the development of the pathogenesis process, with the host plant's ability to control infection to some extent potentially advantageous to the invading virus.

Transgenic expression of Tobacco mosaic virus capsid and movement proteins modulate plant basal defense and biotic stress responses in Nicotiana tabacum.

Plant viruses cause metabolic and physiological changes associated with symptomatic disease phenotypes. Symptoms involve direct and indirect effects, which result in disruption of host physiology. We used transgenic tobacco expressing a variant of Tobacco mosaic virus (TMV) coat protein (CP(T42W)) or movement protein (MP), and a hybrid line (MP×CP(T42W)) that coexpresses both proteins, to study the plant response to individual viral proteins. Findings employing microarray analysis of MP×CP(T42W) plants and silenced mp×cp(T42W)* controls revealed that altered transcripts were mostly downregulated, suggesting a persistent shut-off due to MP×CP(T42W) expression. Next, we showed that MP triggered reactive oxygen species (ROS) accumulation, reduction of total ascorbate, and expression of ROS scavenging genes. These effects were enhanced when both proteins were coexpressed. MP and MP×CP(T42W) plants showed increased levels of salicylic acid (SA) and SA-responsive gene expression. Furthermore, these effects were partially reproduced in Nicotiana benthamiana when GMP1 transcript was silenced. CP(T42W) seems to be playing a negative role in the defense response by reducing the expression of PR-1 and RDR-1. MP and MP×CP(T42W) transgenic expression promoted a recovery-like phenotype in TMV RNA infections and enhanced susceptibility to Pseudomonas syringae and Sclerotinia sclerotiorum. The individual effects of viral proteins may reflect the ability of a virus to balance its own virulence.

Diet and cooling interactions on physiological responses of grazing dairy cows, milk production and composition.

The objective of this trial was to evaluate the effects of diet and cooling in the holding pen before milking on rectal temperature, respiration rate and milk production and composition. Fifty-eight lactating Holstein cows were used in a factorial split-plot design, at Rafaela Experimental Station from 12 January to 3 March 2003. The treatments were combinations of two diets: control (CD) and balanced (BD) with two levels of cooling before milking: none (NSF) and a sprinkler and fans (SF). Forage:concentrate ratios for CD and BD were 81:19 and 68:32, respectively. Cows were milked twice daily. Milk production was recorded daily, and milk composition (fat, protein, lactose and urea) was analysed twice a week. The physiological data were recorded once a week, before the cattle entered the holding pen and after milking, in the afternoon. Average maximum weekly temperature humidity index was 75.4 and ranged from 61.4 to 83. There were highly significant effects of cooling on physiological responses. Milk production was affected by diet and cooling, with no interaction; the highest and lowest production of milk was 22.42 and 20.07 l/cow per day, for BD+SF and CD+NSF, respectively. Protein was affected by diet, and was higher for BD (3.17 vs. 3.08%). There were interaction effects on milk fat at the 8% level, the highest concentration being 3.65% for BD+NFS. It was concluded that under grazing conditions, cooling by sprinkler and fans before milking improves the comfort of dairy cows, and that the effects on milk production and composition are enhanced when diets are specially formulated for heat-stress periods.

Effects of feeding rations with genetically modified whole cottonseed to lactating Holstein cows.

Two experiments were conducted to evaluate dry matter intake (DMI), milk yield, and milk composition from feeding rations that contained different sources of genetically modified whole cottonseed to Argentinean Holstein dairy cows. Twenty-four lactating multiparous Argentinean Holstein dairy cows were used in 2 experiments with a replicated 4 x 4 Latin square design, with cows averaging 565 kg body weight and 53 d in milk at the beginning of the experiments. Treatments in Experiment 1 were: Bollgard cotton containing the cry1Ac gene, Bollgard II cotton containing cry1Ac and cry2Ab genes, Roundup Ready cotton containing the cp4 epsps gene, and a control nongenetically modified but genetically similar cottonseed. In Experiment 2, two commercial sources, a parental control line, and the transgenic cotton containing both cry1Ac and cp4 epsps genes were used as treatments. All cows received the same total mixed ration but with different whole cottonseed sources. Cottonseed was included to provide 2.50 kg per cow daily (dry matter [DM] basis) or about 10% of the total diet DM. The ingredient composition of the total mixed ration was 32% alfalfa hay, 28% corn silage, 22% corn grain, 17% soybean meal, and 2% minerals and vitamins. In addition, genomic DNA was extracted from a subset of milk samples and analyzed by polymerase chain reaction followed by Southern blot hybridization for small fragments of the cry1Ac transgene and an endogenous cotton gene, acp1. No sample was positive for transgenic or plant DNA fragments at the limits of detection for the assays following detailed data evaluation criteria. The DMI, milk yield, milk composition, body weight, and body condition score did not differ among treatments. Cottonseed from genetically modified varieties used in these studies yielded similar performance in lactating dairy cows when compared to non-transgenic control and reference cottonseed.

Synthesis, DNA interaction and antineoplastic activity of semicarbazone derivatives.

A number of antineoplastic agents including procarbazine and bisantrene derive from hydrazine, but so far none have been developed from semicarbazide. In order to assay active minimal structures, thirteen new compounds were prepared by replacing hydrogen atoms in semicarbazone amine group by alkylamine moieties, employing an improved procedure. DNA binding was evaluated by treatment of a drug solution with DNA-cellulose complex and further measurement of remaining drug by UV spectroscopy and the affinity observed to range from medium to weak. On testing these compounds against human neoplastic cell lines, only a nitroderivative proved active on CNS and Breast cell lines at 10(-4) M. This member was studied by cyclic voltammetry.

DNA interaction and electrochemical properties of bis-1-aminomethylnaphthalenes and related compounds. A correlation with their antineoplastic activity.

Bis-1-aminomethylnaphthalenes constitute a new type of molecule with antineoplastic activity. As a first approach to determine the action mechanism, the interaction degree of these compounds and some less active analogous, with calf thymus DNA, by UV spectrophotometry, and the redox performance by cyclic voltammetry was correlated with their activity on neoplastic cell lines. It suggests that the most active members interact closely with DNA but do not show any redox process at biological potentials.

Properties of the isolated rabbit proximal convoluted tubule and pars recta after long-term storage in a modified Collins solution.

The effect of storage of cortical slices in modified Collins solution on the viability of rabbit proximal convoluted tubules (PCT) and pars recta (PR) was evaluated by microperfusion of isolated tubules in vitro. Cortical slices of rabbit kidney were stored for 1, 24, 48, 72 and 97 h at 4 degrees C in modified Collins solution. PCT and PR were dissected from these slices and perfused with a modified Krebs-Henseleit solution in vitro. Fluid absorption (JV) was 1.21 +/- 0.3 nl min-1 mm-1 (N = 8) and the transepithelial potential difference (PD) was -2.3 +/- 0.3 mV (N = 6) for PCT from cortical slices stored 0 to 3 h. JV was 1.01 +/- 0.09 nl min-1 mm-1 (N = 8) and PD was -1.9 +/- 0.6 mV (N = 5) for PCT from tissue stored 23 to 97 h. JV of PR from tissue stored 5 to 26 h was 0.75 +/- 0.1 nl min-1 mm-1 (N = 5) and PD was -1.5 +/- 0.3 mV (N = 5). JV was 0.76 +/- 0.1 nl min-1 mm-1 (N = 3) for PR stored 72 to 74 h, and PD was not measured. There was no correlation between storage time and JV or PD. Furthermore, the JV and PD values for these tubules were similar to those obtained for freshly dissected tubules. These results show that the isolated tubule preparation is useful for the direct assessment of the efficacy of different kidney preservation solutions on nephron function.

Tetracaine, procaine and verapamil inhibition of fluid absorption in isolated perfused rabbit proximal convoluted tubules.

1. We determined the effect of local anesthetic and antiarrhythmic drugs which putatively increase cytosolic Ca2+ activity on fluid absorption (JV) by the isolated perfused proximal convoluted tubule of the rabbit. 2. Rabbit proximal convoluted tubules were perfused in vitro with an ultrafiltrate of modified Krebs-Henseleit solution containing 6.5 g/dl bovine albumin. 3. JV was measured before and after the addition of 2 mM tetracaine, 1 mM procaine or 5 microM verapamil, and after removal of the drugs from the bathing solution (recovery period). 4. All the drugs studied significantly inhibited JV in a reversible manner. 5. The data are consistent with the view that these drugs decreased the rate of fluid absorption in the proximal convoluted tubule by increasing cytosolic Ca2+ activity.

Efeito do inibidor da enzima conversora da angiotensina sobre a funcao renal de caes com expansao do espaco extracelular. / Effect of a converting enzyme inhibitor of the renal function in dogs with expansion of the extracellular space

A maioria dos estudos com o SQ 14225(Squibb), um inibidor da enzima de conversao de angiotensina, foram feitos em animais e pacientes hipertensos. Tendo em vista a possibilidade de a droga ter uma acao farmacologica independente do seu efeito sobre a renina angiotensina, resolvemos estuda-la no seguinte protocolo experimental: Caes normais foram submetidos a uma expansao de 20% do espaco extracelular com solucao salina isotonica para inibir a atividade plasmatica do sistema renina, angiotensina, aldosteroma (S.R.A.A.).Nossas observacoes indicam que o SQ 14225 administrado a caes por via endovenosa, na dose de 7mg/kg e na vigencia de inibicao do S.R.A.A. por expansao com salina, apresentada uma acao hipotensora, assim como provoca proteinuria transitoria, provavelmente por aumentar a permeabilidade da membrana basal glomerular