EPR and magnetic properties of [Mn(μ-Cl)2(bpy)]n: An unusual ferromagnetic interaction in a Mn(II) chloro-bridged polymer

The study of the magnetic properties and EPR spectra of the one-dimensional bis(μ-chloro) Mn(II) polymer [Mn(μ-Cl)₂(bpy)]_n (1) (bpy = 2,2′-bipyridine) is reported. Magnetic susceptibility measurements reveal a weak ferromagnetic interaction between the Mn(II) ions (J = +0.19 cm⁻¹). This is the first polymer of six-coordinated Mn(II) ions with a [Mn₂(μ-Cl)₂]²⁺ magnetic repeating unit, showing a ferromagnetic interaction. The coordination octahedra are elongated in the Cl?Cl direction and the elongation axes are parallel along the chain. Extended Hückel calculations show that the octahedra share an equatorial-apical edge, with the equatorial plane being parallel, and perpendicular to the Mn₂(μ-Cl)₂. Due to this disposition, the overlap through the chloride bridges is small, so the antiferromagnetic contribution must also be small and, therefore, a ferromagnetic behaviour is observed. The EPR spectra of a polycrystalline sample of 1 at different temperatures are also reported. A variation of the bandwidth with temperature is observed, which could be because this ferromagnetic interaction is weak: above 150 K the dipolar interaction is the predominant effect, while below 150 K the magnetic exchange interaction dominates.     

First detection of anti-Besnoitia spp. specific antibodies in horses and donkeys in Italy

Among Apicomplexa protozoa infecting equids, Besnoitia spp., Toxoplasma gondii and Neospora spp. represent important issues from a sanitary and zootechnical viewpoint. However, only scarce epidemiological data are available on the spread of the infections in horses and donkeys in Europe. Therefore, a serosurvey was planned to estimate the prevalence of these Sarcocystidae species in Italian equids. Serum samples from 268 horses and 18 donkeys raised in Italy were collected and serologically analyzed to detect anti-Besnoitia spp., anti-T. gondii and anti-Neospora spp. antibodies: an approach based on an initial screening by in-house ELISA followed by a confirmatory WB was used. Two horses (0.7%) and four donkeys (22.2%), showed antibodies anti-Besnoitia spp. Ten horses (3.7%) resulted positive to T. gondii and one of these (0.4%) was seropositive also to Neospora spp. This is the first detection of anti-Besnoitia spp. specific antibodies in Italian horses and donkeys. The study confirmed the circulation of Besnoitia spp. among equids in Europe. Low prevalence of T. gondii and Neospora spp. in horses raised in Italy was reported. Nevertheless, it is noteworthy to consider that consumption of horse meat could represent a source for human toxoplasmosis.     

Farm‐scale evaluation of the impact of Cry1Ab Bt maize on canopy nontarget arthropods: a 3‐year study

The cultivation of Cry1Ab‐expressing genetically modified MON810 (Bt maize) has led to public concern in Europe, regarding its impact on nontarget arthropods (NTAs). We have assessed the potential effects of DKC 6451 YG (MON810) maize on canopy NTAs in a farm‐scale study performed in Central Spain during 3 years. The study focused on hemipteran herbivores (leafhoppers and planthoppers) and hymenopteran parasitic wasps (mymarids) collected by yellow sticky traps, which accounted for 72% of the total number of insects studied. The dynamics and abundance of these groups varied among years, but no significant differences were found between Bt and non‐Bt maize, indicating that Bt maize had no negative effect on these taxa. Nonetheless, the Cry1Ab toxin was detected in 2 different arthropods collected from Bt maize foliage, the cicadellids Zyginidia scutellaris and Empoasca spp. A retrospective power analysis on the arthropod abundance data for our field trials has determined that Z. scutellaris and the family Mymaridae have high capacity to detect differences between the Bt maize and its isogenic counterpart. The use of these canopy NTAs as surrogates for assessing environmental impacts of Bt maize is discussed.     

INTRA- AND INTERCLONAL COMPETITION IN THE CLEISTOGAMOUS GRASS AMPHIBROMUS SCABRIVALVIS

The relationship of differences in life history traits among genotypes to competitive ability is not well known for most clonal plants. It has been hypothesized that genetically identical clones will compete more intensively than genetically distinct clones. The perennial grass Amphibromus scabrivalvis, which produces basal corms and cleistogamous seeds enclosed by leaf sheaths, exhibits pronounced clonal growth via rhizome and ramet production. In a controlled greenhouse experiment, clones of four genotypes of this species were grown under three regimes: alone in the absence of competition, paired with a clone of the same genotype (intraclonal competition), and paired with a clone of a different genotype (interclonal competition). There were differences in some biomass measures and in ramet and corm production among the four genotypes grown in the absence of competition. All genotypes showed a significant reduction in total biomass under both intra- and interclonal conditions, indicating that competition had occurred. For three of four genotypes, biomass allocation to corm increased under competition, while allocation to cleistogamous seeds was constant or increased slightly. Although some genotypes in specific interclonal combinations were less affected by competition than in intraclonal combinations, there was no support for the contention that the effects of competition were more intense for genetically identical clones.     

White‐tailed deer as the last megafauna dispersing seeds in Neotropical dry forests: the role of fruit and seed traits

Endozoochory is a prominent form of seed dispersal in tropical dry forests. Most extant megafauna that perform such seed dispersal are ungulates, which can also be seed predators. White‐tailed deer (Odocoileus virginianus) is one of the last extant megafauna of Neotropical dry forests, but whether it serves as a legitimate seed disperser is poorly understood. We studied seed dispersal patterns and germination after white‐tailed deer gut passage in a tropical dry forest in southwest Ecuador. Over 23 mo, we recorded ca 2000 seeds of 11 species in 385 fecal samples. Most seeds belonged to four species of Fabaceae: Chloroleucon mangense, Senna mollissima, Piptadenia flava, and Caesalpinia glabrata. Seeds from eight of the 11 species dispersed by white‐tailed deer germinated under controlled conditions. Ingestion did not affect germination of C. mangense and S. mollissima, whereas C. glabrata showed reduced germination. Nevertheless, the removal of fruit pulp resulting from ingestion by white‐tailed deer could have a deinhibition effect on germination due to seed release. Thus, white‐tailed deer play an important role as legitimate seed dispersers of woody species formerly considered autochorous. Our results suggest that more research is needed to fully understand the ecological and evolutionary effects of the remaining extant megafauna on plant regeneration dynamics in the dry Neotropics.     

Optopharmacological control of TRPC channels by coumarin-caged lipids is associated with a phototoxic membrane effect

Photouncaging of second messengers has been successfully employed to gain mechanistic insight of cellular signaling pathways. One of the most enigmatic processes of ion channel regulation is lipid recognition and lipid-gating of TRPC channels, which represents pivotal mechanisms of cellular Ca~(2+) homeostasis. Recently, optopharmacological tools including caged lipid mediators became available, enabling an unprecedented level of temporal and spatial control of the activating lipid species within a cellular environment. Here we tested a commonly used caged ligand approach for suitability to investigate TRPC signaling at the level of membrane conductance and cellular Ca~(2+) handling. We report a specific photouncaging artifact that is triggered by the cage structure coumarin at UV illumination. Electrophysiological characterization identified a light-dependent membrane effect of coumarin. UV light(340 nm) as used for photouncaging, initiated a membrane conductance specifically in the presence of coumarin as low as 30 μmol L~(-1) concentrations. This conductance masked the TRPC3 conductance evoked by photouncaging, while TRPC-mediated cellular Ca~(2+) responses were largely preserved. The observed light-induced membrane effects of the released caging moiety may well interfere with certain cellular functions, and prompt caution in using coumarin-caged second messengers in cellular studies.     

Persistence of Anticancer Activity in Berry Extracts after Simulated Gastrointestinal Digestion and Colonic Fermentation

Fruit and vegetable consumption is associated at the population level with a protective effect against colorectal cancer. Phenolic compounds, especially abundant in berries, are of interest due to their putative anticancer activity. After consumption, however, phenolic compounds are subject to digestive conditions within the gastrointestinal tract that alter their structures and potentially their function. However, the majority of phenolic compounds are not efficiently absorbed in the small intestine and a substantial portion pass into the colon. We characterized berry extracts (raspberries, strawberries, blackcurrants) produced by in vitro-simulated upper intestinal tract digestion and subsequent fecal fermentation. These extracts and selected individual colonic metabolites were then evaluated for their putative anticancer activities using in vitro models of colorectal cancer, representing the key stages of initiation, promotion and invasion. Over a physiologically-relevant dose range (0–50 µg/ml gallic acid equivalents), the digested and fermented extracts demonstrated significant anti-genotoxic, anti-mutagenic and anti-invasive activity on colonocytes. This work indicates that phenolic compounds from berries undergo considerable structural modifications during their passage through the gastrointestinal tract but their breakdown products and metabolites retain biological activity and can modulate cellular processes associated with colon cancer.     

A revision of the genus Neogrubea Dillon & Hargis, 1968 (Monogenea: Mazocraeidae): new morphological and molecular data from off the Patagonian coast of Argentina

The genus Neogrubea Dillon & Hargis, 1968 (syn. Asymmetria Suriano, 1975) is revised based on examination of type- and voucher material, and from new specimens collected from the gills of Seriolella porosa Guichenot and Stromateus brasiliensis Fowler from off Patagonia, Argentina. Morphological comparisons based on light and scanning electron microscopy and molecular data (partial SSU and LSU rDNA sequences) of the monogeneans from off Patagonia suggest that N. seriolellae Dillon & Hargis, 1968 (syns N. stromateae Gibson, 1976, A. asymmetria Suriano, 1975 and A. platensis Rey & Meneses, 1985) is currently the only species of the genus. Neogrubea soni Evdokimova, 1969 is considered a species inquirenda. An emended diagnosis of Neogrubea is presented, and new host and locality records for N. seriolellae are given in detail. Morphological characters of the members of the mazocraeid subfamily Grubeinae Price, 1961 are also discussed.     

Plant species influence on soil microbial short-term response after fire simulation

Aims

Plant species can influence fire intensity and severity causing different immediate and long-term responses on the soil microbial community. The main objective of this work was to determine the role of two representative Mediterranean plant species as soil organic matter sources, and to identify their influence on microbial response before and after heat exposure.

Methods

A laboratory heating experiment (300 °C for 20 min) was performed using soil collected under Pinus hallepensis (PIN) and Quercus coccifera (KER). Dried plant material was added before heating for a total of six different treatments: non-heated control samples amended with the original plant material (PIN₀ and KER₀); PIN samples heated with pine (PIN_p) or kermes oak litter (PIN_k); KER samples heated with kermes oak (KER_k) or pine litter (KER_p). Heated soils were inoculated with the original fresh soil and different microbial parameters related to abundance, activity and possible changes in microbial community composition and chemical soil parameters that could be conditioning microbial response were measured for 28 days after inoculation.

Results

The effect of heating on the soil microbial parameters studied was influenced to a small extent by the plant species providing fuel, being evident in soil samples taken under pine influence. Nevertheless heating effect showed marked differences when plant species influence on soil origin was analyzed.

Conclusions

In general, samples taken under pine appear to be more negatively affected by heating treatment than samples collected under kermes oak, highlighting the importance of vegetation as a fresh organic matter source in soil ecosystems before and after fire.