Production of l-lactic acid with immobilized Lactobacillus delbrueckii

Summary Living Lactobacillus delbrueckii cells were entrapped in calcium alginate gel beads and employed both in recycle batch and continuous column reactors to produce l-lactic acid from glucose. The substrate contained l% (w/v) yeast extract as nutrient and 4.8% (w/v) solid calcium carbonate as buffer. The maxiumum lactic acid yield obtained was 97%, of which more than 90% was l-lactic acid. The biocatalyst activity half-life in continuous operation was about 100 d, and only about 10% of the activity was lost during intermittent storage of the bioreactor at +7°C for about 5 months.     

SSU rDNA phylogeny of cladoniiform lichens

To examine phylogenetic relationships among the "cladoniiform" lichenized fungi, i.e., the families Cladoniaceae, Baeomycetaceae, Icmadophilaceae, Stereocaulaceae, and Siphulaceae, and to provide evidence for the anticipated independent origins of podetia and pseudopodetia, we conducted phylogenetic analyses of SSU (small subunit) rDNA sequences from 39 lichen-forming fungi. These fungi represent all of the major growth forms of lichen associations, fruticose (including "cladoniiform"), foliose, and crustose. Our analysis suggests that lichen-forming fungi with a "cladoniiform" morphology arose multiple times within the ascomycetes. Additionally, each of the other thallus growth forms, crustose, foliose, and fruticose, have originated multiple times. It also seems to be clear that neither all podetiate nor all pseudopodetiate taxa form a monophyletic group. Therefore the term "podetium" should be restricted to homologous structures that are most probably limited to the genera Cladonia, Cladina, Pycnothelia, and allies. The "pseudopodetia" of Stereocaulon (Stereocaulaceae) and Cladia (Cladiaceae) may represent different states of the same homologous character. Our phylogenetic hypothesis supports the monophyletic origin of the order Lecanorales sensu stricto, including representatives of five suborders Cladoniineae, Lecanorineae, Teloschistineae, Agyriineae and Peltigerineae, but excluding representatives of the suborders Acarosporineae (Acarospora schleicheri and Megaspora verrucosa), Pertusariineae (Pertusaria trachythallina), and Umbilicarineae. The suborder Cladoniineae and the family Cladoniaceae both appear to be polyphyletic assemblages.     

Variants in the interleukin-1 alpha and beta genes,and the risk for periodontal disease in dogs

Elevated levels of interleukin-1 (IL-1) have been shown to amplify the inflammatory response against periodontopathogenic bacteria. In humans, polymorphisms in the IL1A and IL1B genes are the most well-studied genetic polymorphisms associated with periodontal disease (PD). In contrast to human, there is a lack of knowledge on the genetic basis of canine PD. A case–control study was conducted in which a molecular analysis of dog IL1A and IL1B genes was performed. Of the eight genetic variants identified, seven in IL1A gene and one in IL1B gene, IL1A/1_g.388A >C and IL1A/1_g.521T >A showed statistically significant differences between groups (adjusted OR (95% CI): 0.15 (0.03–0.76), P= 0.022; 5.76 (1.03–32.1), P= 0.046, respectively). It suggests that in the studied population the IL1A/1_g.388C allele is associated with a decreased PD risk, whereas the IL1A/1_g.521A allele can confer an increased risk. Additionally, the IL1A/2_g.515G >T variation resulted in a change of amino acid, i.e. glycine to valine. In silico analysis suggests that this change can alter protein structure and function, predicting it to be deleterious or damaging. This work suggests that IL1 genetic variants may be important in PD susceptibility in canines.     

Testing the quick meal hypothesis: The effect of pulp on hoarding and seed predation of Hymenaea courbaril by red‐rumped agoutis (Dasyprocta leporina)

Abstract: Red‐rumped agoutis (Dasyprocta leporina) are important seed dispersers/predators of Neotropical large‐seeded plants. Several species of seeds cached by agoutis have an edible reward, in contrast to temperate rodent‐dispersed diaspores. The quick meal hypothesis states that the presence of a reward such as edible pulp will enhance the efficiency of rodents as seed disperses by satiating the animal and, consequently, reducing seed predation and enhancing hoarding. In this study, this hypothesis was tested using as the reference system the pulp and seeds of Hymenaea courbaril. Seeds with and without pulp were offered to agoutis and the behaviour of each individual was recorded. Since the probability of predation and hoarding were complementary, we used the probability of predation. The proportion of agoutis that preyed on at least one seed was similar for seeds with (42.8% of individuals) and without (40.0% of individuals) pulp. In agoutis that preyed upon at least one seed, the probability that they killed a seed did not differ between seeds with (0.17 ± 0.03) and without (0.20 ± 0.08) pulp. Hence, these results do not support the ‘quick meal hypothesis’.     

Extrafloral nectaries as a deterrent mechanism against seed predators in the chemically protected weed Crotalaria pallida (Leguminosae)

Abstract In several plants, extrafloral nectaries (EFN) are located close to the reproductive structures, suggesting that ants may act as a defence against specialized seed predators that overcome chemical defences. Alternatively, ants may also deter herbivores in a generalized manner, thereby protecting the whole plant. In this work, we examined the relationship between the chemically protected weed Crotalaria pallida Ait. (Leguminosae) that bears EFN, its specialized seed predator, the larvae of the arctiid moth Utetheisa ornatrix L. (Arctiidae) and ants. We tested two hypotheses related to the type of deterrence caused by ants. The Seed Predator Deterrence Hypothesis predicts that ant deterrence is directed primarily towards herbivores that destroy seeds and other reproductive structures, without attacking herbivores on vegetative structures. The General Deterrence Hypothesis states that ants are general in their effects, equally deterring herbivores in vegetative and reproductive structures. Our results supported the predictions of the Seed Predator Deterrence Hypothesis, namely, that (i) ant activity on EFN was related to the vulnerability of reproductive structures to attack by U. ornatrix; (ii) ant patrolling was restricted almost entirely to racemes; (iii) ants removed termites used as baits more frequently on racemes than on leaves; and (iv) U. ornatrix larvae were often expulsed from the racemes. These results indicate that EFN can act as another deterrent mechanism in chemically protected plants by promoting the expulsion of specialist seed predators.     

Prediction of indirect interactions in proteins

Background  

Both direct and indirect interactions determine molecular recognition of ligands by proteins. Indirect interactions can be defined as effects on recognition controlled from distant sites in the proteins, e.g. by changes in protein conformation and mobility, whereas direct interactions occur in close proximity of the protein's amino acids and the ligand. Molecular recognition is traditionally studied using three-dimensional methods, but with such techniques it is difficult to predict the effects caused by mutational changes of amino acids located far away from the ligand-binding site. We recently developed an approach, proteochemometrics, to the study of molecular recognition that models the chemical effects involved in the recognition of ligands by proteins using statistical sampling and mathematical modelling.     

REINTERPRETATION OF A CONULARIID-LIKE FOSSIL FROM THE VENDIAN OF RUSSIA

Abstract:  Vendoconularia triradiata Ivantsov and Fedonkin, recently described from Vendian (latest Proterozoic) strata of Russia, has been interpreted as a six-sided conulariid cnidarian. However, comparison of published illustrations of V .  triradiata with Palaeozoic conulariids suggests that certain key features of the anatomy of V .  triradiata should be reinterpreted. Specifically, features previously homologized with the corners of conulariid thecae may actually be homologous to the conulariid midlines. Under this new interpretation, the corners of the Vendoconularia theca were sulcate, and the midline of each face was non-sulcate and flanked by a pair of low internal carinae. This alternative set of hypotheses of homology makes the argument for a conulariid affinity for Vendoconularia stronger.     

Pseudomonas fluorescens' view of the periodic table

Growth in a biofilm modulates microbial metal susceptibility, sometimes increasing the ability of microorganisms to withstand toxic metal species by several orders of magnitude. In this study, a high-throughput metal toxicity screen was initiated with the aim of correlating biological toxicity data in planktonic and biofilm cells to the physiochemical properties of metal ions. To this end, Pseudomonas fluorescens ATCC 13525 was grown in the Calgary Biofilm Device (CBD) and biofilms and planktonic cells of this microorganism were exposed to gradient arrays of different metal ions. These arrays included 44 different metals with representative compounds that spanned every group of the periodic table (except for the halogens and noble gases). The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum biofilm eradication concentration (MBEC) values were obtained after exposing the biofilms to metal ions for 4 h. Using these values, metal ion toxicity was correlated to the following ion-specific physicochemical parameters: standard reduction-oxidation potential, electronegativity, the solubility product of the corresponding metal–sulfide complex, the Pearson softness index, electron density and the covalent index. When the ions were grouped according to outer shell electron structure, we found that heavy metal ions gave the strongest correlations to these parameters and were more toxic on average than the other classes of the ions. Correlations were different for biofilms than for planktonic cells, indicating that chemical mechanisms of metal ion toxicity differ between the two modes of growth. We suggest that biofilms can specifically counter the toxic effects of certain physicochemical parameters, which may contribute to the increased ability of biofilms to withstand metal toxicity.     

CLADISTIC ANALYSIS OF THE SUBORDER CONULARIINA MILLER AND GURLEY, 1896 (CNIDARIA, SCYPHOZOA; VENDIAN–TRIASSIC)

Abstract: Results of a cladistic analysis of the suborder Conulariina Miller and Gurley, 1896, a major extinct (Vendian–Triassic) group of scyphozoan cnidarians, are presented. The analysis sought to test whether the three conulariid subfamilies (Conulariinae Walcott, 1886 , Paraconulariinae Sinclair, 1952 and Ctenoconulariinae Sinclair, 1952 ) recognized in the Treatise on Invertebrate Paleontology (TIP) are monophyletic. A total of 17 morphological characters were scored for 16 ingroup taxa, namely the genera Archaeoconularia, Baccaconularia, Climacoconus, Conularia, Conulariella, Conularina, Ctenoconularia, Eoconularia, Glyptoconularia, Metaconularia, Notoconularia, Paraconularia, Pseudoconularia, Reticulaconularia, Teresconularia and Vendoconularia. The extant medusozoan taxa Cubozoa, Stauromedusae, Coronatae and Semaeostomeae served as outgroups. Unweighted analysisof the data matrix yielded 1057 trees, and successive weighting analysis resulted in one of the 1057 original trees. The ingroup is monophyletic with two autapomorphies: (1) the quadrate geometry of the oral region; and (2) the presence of a mineralized (phosphatic) periderm. Within the ingroup, the clade (Vendoconularia, Teresconularia, Conularina, Eoconularia) is supported by the sinusoidal longitudinal geometry of the transverse ridges, and the much larger clade (Baccaconularia, Glyptoconularia, Metaconularia, Pseudoconularia, Conularia, Ctenoconularia, Archaeoconularia, Notoconularia, Climacoconus, Paraconularia, Reticulaconularia) is supported by the presence of external tubercles, which, however, were lost in the clade (Notoconularia, Climacoconus, Paraconularia, Reticulaconularia). As proposed by Van Iten et al. (2000) , the clade (Notoconularia, Climacoconus, Paraconularia, Reticulaconularia) is supported by the termination and alternation of the transverse ribs in the corner sulcus. The previously recognized subfamilies Conulariinae, Paraconulariinae and Ctenoconulariinae were not recovered from this analysis. The diagnostic features of Conulariinae (continuation of the transverse ornament across the corner sulcus and lack of carinae) and Ctenoconulariinae (presence of carinae) are symplesiomorphic or homoplastic, and Paraconulariinae is polyphyletic. The families Conulariellidae Kiderlen, 1937 and Conulariopsidae Sugiyama, 1942 , also recognized in the TIP, are monogeneric, and since they provide no additional phylogenetic information, should be abandoned.