Protection from murine cysticercosis by immunization with a parasite cysteine protease

Central nervous system infection by Taenia solium cysts causes neurocysticercosis, a common neurological infection in the Third World. We have previously isolated cysteine proteases from Taenia crassiceps and T. solium. In this study, we immunized BALB/c mice with the purified T. solium cysteine protease and challenged them with Taenia crassiceps. Immunized mice had a 72% reduction in parasite burden compared to mice that received no immunization. Immunized mice developed antigen specific lymphocyte proliferation. These data support further studies of the T. solium cysteine protease as a vaccine candidate.     

Passive serum therapy with polyclonal antibodies against Mycobacterium tuberculosis protects against post-chemotherapy relapse of tuberculosis infection in SCID mice

We investigated the protective role of immune-sera against reactivation of Mycobacterium tuberculosis infection in SCID mice and found that passive immunization with sera obtained from mice treated with detoxified M. tuberculosis extracts (delivered in liposomes in a composition known as RUTI) exerted significant protection. Our SCID mouse model consisted of aerosol infection by M. tuberculosis, followed by 3 to 8weeks of chemotherapy with isoniazid+rifampicin (INH+RIF) (25 and 10mg/kg, respectively). After infection and antibiotic administration, two groups of mice were treated for up to 10weeks with intraperitoneal passive immunization using hyperimmune serum (HS) obtained from mice infected with M. tuberculosis, treated with chemotherapy (INH+RIF) for 8weeks and inoculated with RUTI (HS group) or with normal serum (CT group). Significant differences were found between HS and CT groups in the number of bacilli in the lungs (3.68+/-2.02 vs. 5.72+/-1.41log(10) c.f.u.), extent of pulmonary granulomatomous infiltration (10.33+/-0.67 vs. 31.2+/-1.77%), and percentage of animals without pulmonary abscesses (16.7% vs. 45.5%). These data strongly suggest a protective role of specific antibodies against lung dissemination of M. tuberculosis infection.     

DNA damage in mouse lymphocytes exposed to curcumin and copper

Dietary polyphenolics, such as curcumin, have shown antioxidant and anti-inflammatory effects. Some antioxidants cause DNA strand breaks in excess of transition metal ions, such as copper. The aim of this study was to evaluate thein vitro effect of curcumin in the presence of increasing concentrations of copper to induce DNA damage in murine leukocytes by the comet assay. Balb-C mouse lymphocytes were exposed to 50 μM curcumin and various concentrations of copper (10 μM, 100 μM and 200 μM). Cellular DNA damage was detected by means of the alkaline comet assay. Our results show that 50 μM curcumin in the presence of 100–200 μM copper induced DNA damage in murine lymphocytes. Curcumin did not inhibit the oxidative DNA damage caused by 50 μM H₂O₂ in mouse lymphocytes. Moreover, 50 μM curcumin alone was capable of inducing DNA strand breaks under the tested conditions. The increased DNA damage by 50 μM curcumin was observed in the presence of various concentrations of copper, as detected by the alkaline comet assay.     

Dehydroepiandrosterone decreases while cortisol increases in vitro growth and viability of Entamoeba histolytica

In vitro exposure of Entamoeba histolytica trophozoites to the sex steroids 17beta-estradiol, progesterone, and dehydrotestosterone had little effect on parasite viability or proliferation. However, treatment with the adrenal steroid dehydroepiandrosterone (DHEA) markedly inhibited parasite proliferation, adherence and motility, and at a certain dose it induced trophozoite lysis. The opposite effect on proliferation was found when the trophozoites were exposed to cortisol. Moreover, DHEA decreased while cortisol increased the parasite's DNA synthesis determined by 3H-thymidine incorporation. Trophozoite lysis by DHEA appeared to be caused by a necrotic rather than an apoptotic process, as observed in propidium iodide and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling assays. A possible mechanisms of action was derived from experiments demonstrating that the activity of a putative 3-hydroxy-3-methyl glutaryl CoA reductase detected in trophozoite extracts was inhibited in the presence of DHEA. Contrary to its in vitro inhibitory effect, in vivo administration of DHEA to infected hamsters resulted in exacerbation of the amebic liver abscesses. These results demonstrated that androgen steroids act directly upon E. histolytica growth and viability, and may shed new light on some age and gender differences in disease progression, as well as finding application in the drug treatment of human amebiasis.     

Plant neurobiology: an integrated view of plant signaling

Plant neurobiology is a newly focused field of plant biology research that aims to understand how plants process the information they obtain from their environment to develop, prosper and reproduce optimally. The behavior plants exhibit is coordinated across the whole organism by some form of integrated signaling, communication and response system. This system includes long-distance electrical signals, vesicle-mediated transport of auxin in specialized vascular tissues, and production of chemicals known to be neuronal in animals. Here we review how plant neurobiology is being directed toward discovering the mechanisms of signaling in whole plants, as well as among plants and their neighbors.     

Can plant biochemistry contribute to understanding of invasion ecology?

Ecologists have long searched for an explanation as to why some plant invaders become much more dominant in their naturalized range than in their native range, and, accordingly, several non-exclusive ecological hypotheses have been proposed. Recently, a biochemical explanation was proposed--the "novel weapons hypothesis"--based on findings that Centaurea diffusa and Centaurea maculosa produce bioactive compounds (weapons) that are more active against na?ve plant species in the introduced range than against co-evolved species in the native range. In this Opinion article, we revise and expand this biochemical hypothesis and discuss experimental and conceptual advances and limitations.     

Demography of the cycad Ceratozamia mirandae (Zamiaceae) under disturbed and undisturbed conditions in a biosphere reserve of Mexico

The cycad Ceratozamia mirandae is endemic to Chiapas, Mexico. Demographic studies were made in two of its populations in the Sepultura Biosphere Reserve under different conservation conditions; in the nucleus zone “Tres Picos” (conserved) and buffer zone “La Sombra” (disturbed and under management). Spatial distribution of C. mirandae was aggregated, showed a clumped local distribution on shallow soils on steep slopes and male and female cones appear to be synchronous in both populations. The population structure was of type I (Bongers) for both sites. Individuals between the sites showed differences in growth pattern. The oldest plants (80–90 cm tall) were estimated to be about 490 years at “La Sombra”. The finite growth rate () in the buffer zone population showed a tendency for decrease whilst in the nucleus zone this estimate remained stable. The highest elasticity values lied in the transition of the first three classes of the “La Sombra” population, in “Tres Picos” this corresponded to adult plants between 20 and 30 cm tall. Given the above, it is proposed that in the nucleus zone, reproductive adults should be of highest conservation priority, whereas in the buffer zone seedling reintroduction should be carried out regularly until the population increases. We recommend an IUCN Red List category of Vulnerable (VU C, 2a), largely due to difficult-to-control destructive annual forest fires that occur in this Reserve.     

Restoring Quercus pyrenaica forests using pioneer shrubs as nurse plants

Question: How to improve reforestation success of Quercus pyrenaica. Location: 1800 m a.s.L, southern Spain. Methods: One‐year‐old Quercus pyrenaica seedlings were planted using two treatments: (1) bare soil, using a 30‐cm diameter augur bit (conventional technique) and (2) under the canopy of a pioneer shrub, Salvia lavandulifolia, using a 12‐cm diameter augur bit. Survival and growth were monitored for six years. Our hypothesis is that the use of shrubs as nurse plants is an alternative technique of reforestation with higher success than traditional techniques, in which pre‐existing vegetation is usually considered a source of competition. The rationale for the study was that for environments with a dry season, pre‐existing vegetation buffers summer drought stress, ameliorates the water status of seedlings and thus usually increases seedling recruitment. Results: Quercus survival was 6.3 × higher when planted under individuals of the pioneer shrub as compared to open areas. Quercus seedlings under shrubs also had shoots 1.8 X longer, while the number of shoots per plant did not differ among treatments. The first summer was the period with the highest mortality (49.1% of seedlings). Summer drought was the main cause of mortality. Conclusions: The use of shrubs as nurse plants for Q.pyrenaica reforestation is a viable technique to increase establishment success. The technique could be similarly useful in other environments with a dry period and for other Quercus species. In addition, this technique offers the advantage of following natural succession, thus minimizing the impact in the community.     

A new species of Cardicola Short, 1953 (Digenea: Sanguinicolidae) parasitizing the Brazilian flathead, Percophis brasiliensis Quoy et Gaimard 1824, from the coasts of Mar del Plata, Argentina

Cardicola ambrosioi n. sp. (Digenea: Sanguinicolidae) is found in the blood vessels of liver and gills of the Brazilian flathead, Percophis brasiliensis Quoy and Gaimard, 1824 (Pisces: Percophidae), from Mar del Plata, Argentina. Among the 13 known species within Cardicola Short, 1953, the new species closely resembles Cardicola coridodacis Manter, 1954, from which it is distinguished by having a relatively shorter oesophagus, the vitellaria extending anteriorly to the nerve commissure, rather than to the end of anterior caeca, the female pore located closer to male pore, the latter situated medially instead of laterally and by possessing a larger Mehlis gland and a smaller seminal vesicle.     

Multiplex PCR for simultaneous detection of five virulence hemolysin genes in Vibrio anguillarum

A multiplex PCR was developed for detection of hemolysin-producing Vibrio anguillarum using primers targeting five hemolysin genes (vah1, vah2, vah3, vah4 and vah5). This method was successful in amplifying reactions containing as little as 100 fg of genomic template DNA. The direct detection of V. anguillarum in clinical specimens by this multiplex PCR was also successful in reactions containing as few as 10 bacterial cells. This multiplex PCR method can be a rapid and sensitive method for detecting pathogenic V. anguillarum.