Mycosphaerella fijiensis is the etiological agent of Black Sigatoka, a fungal disease that affects production of banana and plantain crops in tropical regions. The sizes of cultivable epiphytic and endophytic bacterial populations, aerobic endospore forming bacteria (AEFB), and antagonist bacteria against M. fijiensis isolated from three Musa spp. cultivars from Urabá (Colombia) were studied, in order to find a suitable screening strategy to isolate antagonistic bacteria. Most of the variability found in the epiphytic and endophytic bacterial community sizes among fruit trees was explained by the cultivar differences. We found population sizes ranging from 1.25 × 10(3) to 9.64 × 10(5) CFU/g of fresh leaf and found that 44 % of total cultivable bacteria belong to the AEFB group. We isolated 648 AEFB from three different cultivars and assessed their antagonistic activity against M. fijiensis using the cell-free supernatant obtained from bacterial liquid cultures in three different in vitro assays. Five percent of those bacteria showed higher percent inhibition than the positive control Bacillus subtilis UA321 has (percent inhibition = 84 ± 5) in the screening phase. Therefore, they were selected as antagonistic bacteria against the pathogen. The strains with the highest percentage of antagonism were found in older leaves for the three cultivars, given support to recommend this group of leaves for future samplings. Some of these isolated bacteria affected the mycelium and ascospores morphology of the fungus. They also presented in vitro characteristics related to a successful colonization of the phylloplane such as indolic compounds, surfactant production, and biofilm formation, which makes them possible, potential candidates as biological control agents.

The spectacled caiman (Caiman crocodilus) is currently considered to be a species complex due to the relatively high morphological and molecular diversity expressed across its range. One of the populations of interest, inhabiting the Apaporis River (Colombia), was described based on skull features as an incipient species (C. c. apaporiensis) and has been treated by some authors as a full species. Recent molecular work challenged this hypothesis, because relatively low mitochondrial molecular differentiation was found between the morphologically described Apaporis caiman and C. crocodilus (s.s.) Amazonian populations. Here, we present an update on the topic based on a larger molecular sample size and on analysis of expanded geometric morphometric data that include six newly collected skulls. Morphometric data support the existence of previously recognized morphotypes within the complex in Colombia and demonstrate that the newly collected material can be assigned to the classic Apaporis caiman morphotype. However, our expanded genetic analysis fails to find appreciable mitochondrial molecular divergence of the Apaporis caiman population from the C. c. crocodilus population (COI-CytB: Amazon Peru 0.17 ± 0.06%, CytB-only: Caquetá River Colombia 0.08 ± 0.07%). The Apaporis caiman is interpreted to be a phenotypically distinct member of the cis-Andean C. crocodilus metapopulation that has not yet achieved (or may not be undergoing at all) appreciable genetic differentiation. Thus, it should not be considered a fully independent evolutionary lineage, nor given full species rank.

In this work, the Box-Benkhen experimental Design (BBD) was applied for the optimization of the parameters of the electrocatalytic degradation of wastewaters resulting from a phenolic resins industry placed in the suburbs of Medellin (Colombia). The direct and the oxidant assisted electro-oxidation experiments were carried out in a laboratory scale batch cell reactor, with monopolar configuration, and electrodes made of graphite (anode) and titanium (cathode). A multifactorial experimental design was proposed, including the following experimental variables: initial phenol concentration, conductivity, and pH. The direct electro-oxidation process allowed to reach ca. 88% of phenol degradation, 38% of mineralization (TOC), 52% of Chemical Oxygen Demand (COD) degradation, and an increase in water biodegradability of 13%. The synergetic effect of the electro-oxidation process and the respective oxidant agent (Fenton reactant, potassium permanganate, or sodium persulfate) let to a significant increase in the rate of the degradation process. At the optimized variables values, it was possible to reach ca. 99% of phenol degradation, 80% of TOC and 88% of COD degradation. A kinetic study was accomplished, which included the identification of the intermediate compounds generated during the oxidation process.

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Caiman crocodilus is an alligatoroid broadly distributed in the neotropics from Mexico to Brazil, where Colombia is the only country that has the complete subspecies complex distributed in its territory. This species has been the focus of many genetic, ecological and morphological studies. However, these studies are limited to traditional morphology methods or have limitations to examine interspecific variation among the four subspecies reported in Colombia. This is the first study of intraspecific variation in the skull of Caiman crocodilus complex distributed in Colombia, using a two-dimensional approach of geometric morphometric on 122 post-hatching ontogenetic cranial series. Morphological differences between species and changes during ontogeny (snout increases its length and, skull roof and orbits decrease their proportions) that represents part of morphological changes in the cranial ontogeny of crocodilians were found. In the morphospace, there was a significant differentiation of C. crocodilus apaporiensis and C. crocodilus crocodilus from C. crocodilus fuscus and C. crocodilus chiapasius. Results from this study revealed that C. crocodilus apaporiensis is a differentiated group from the global complex as well as that the specimens of C. crocodilus chiapasius collected from Medem in Colombia may be showing cryptic morphology in some traits.