The inheritance and chromosomal localization of AFLP markers in a non-inbred potato offspring

AFLP^TM is a new technique to generate large numbers of molecular markers for genetic mapping. The method involves the selective amplification of a limited number of DNA restriction fragments out of complex plant genomic DNA digests using PCR. With six primer combinations 264 segregating AFLP amplification products were identified in a diploid backcross population from non-inbred potato parents. The identity of an AFLP marker was specified by the primer combination of the amplification product and its size estimated in bases. The segregating AFLP amplification products were mapped by using a mapping population with 217 already known RFLP, isozyme and morphological trait loci. In general, the AFLP markers were randomly distributed over the genome, although a few clusters were observed. No indications were found that AFLP markers are present in other parts of the genome than those already covered by RFLP markers. Locus specificity of AFLP markers was demonstrated because equally sized amplification products segregating from both parental clones generally mapped to indistinguishable maternal and paternal map positions. Locus specificity of AFLP amplification products will allow to establish the chromosomal identity of linkage groups in future mapping studies.Since AFLP technology is a multi-locus detection system, it was not possible to identify the AFLP alleles which belong to a single AFLP locus. The consequences of a genetic analysis based on single alleles, rather than on loci with two or more alleles on mapping studies using progenies of non-inbred parents are discussed.     

Nonaggressive behavior: A strategy employed by an obligate nest invader to avoid conflict with its host species

In addition to its builders, termite nests are known to house a variety of secondary opportunistic termite species so‐called inquilines, but little is known about the mechanisms governing the maintenance of these symbioses. In a single nest, host and inquiline colonies are likely to engage in conflict due to nestmate discrimination, and an intriguing question is how both species cope with each other in the long term. Evasive behaviour has been suggested as one of the mechanisms reducing the frequency of host‐inquiline encounters, yet, the confinement imposed by the nests' physical boundaries suggests that cohabiting species would eventually come across each other. Under these circumstances, it is plausible that inquilines would be required to behave accordingly to secure their housing. Here, we show that once inevitably exposed to hosts individuals, inquilines exhibit nonthreatening behaviours, displaying hence a less threatening profile and preventing conflict escalation with their hosts. By exploring the behavioural dynamics of the encounter between both cohabitants, we find empirical evidence for a lack of aggressiveness by inquilines towards their hosts. Such a nonaggressive behaviour, somewhat uncommon among termites, is characterised by evasive manoeuvres that include reversing direction, bypassing and a defensive mechanism using defecation to repel the host. The behavioural adaptations we describe may play an important role in the stability of cohabitations between host and inquiline termite species: by preventing conflict escalation, inquilines may improve considerably their chances of establishing a stable cohabitation with their hosts.     

Length-weight relationships of ornamental fish species from Amanã Lake,Amanã Reserve,Amazonas, Brazil

Length-weight relationships (LWRs) were estimated for 16 ornamental fish species from Amanã Lake and nine tributary streams, in Central Brazilian Amazonia. Sampling was carried out bimonthly for a year (2007–2008), using two sets of four gillnets (20 m × 2 m, 2,5; 3,5; 04; 4,5 cm stretch mesh size); trawls were performed with seine nets (35 m × 6 m, 3 mm stretch mesh size); native fish-traps (fyke-net like fish-traps woven from local lianas), and dip nets (0.5 m × 0.5 m stretch mesh size). Measurements were done for standard length (SL – 0.1 cm precision) and total weight (Wt – 0.01 g precision). This study provides information on the length–weight relationships for all sampled species and, in addition, provides new maximum standard lengths for six species.     

Genetic divergence between Melipona quadrifasciata Lepeletier (Hymenoptera,Apidae) populations

Melipona quadrifasciata is a stingless bee widely found throughout the Brazilian territory, with two recognized subspecies, M. quadrifasciata anthidioides, that exhibits interrupted metasomal stripes, and M. quadrifasciata quadrifasciata, with continuous metasomal stripes. This study aimed to estimate the genetic variability of these subspecies. For this purpose, 127 colonies from 15 Brazilian localities were analyzed, using nine species-specific microsatellite primers. At these loci, the number of alleles ranged from three to 15 (mean: 7.2), and the observed heterozygosity (H_o) ranged from 0.03–0.21, while the expected heterozygosity (H_e) ranged from 0.23–0.47. The genetic distances among populations ranged from 0.03–0.45. The F_ST multilocus value (0.23) indicated that the populations sampled were structured, and the clustering analysis showed the formation of two subgroups and two more distant populations. The first group contained the subspecies M. quadrifasciata quadrifasciata, and the other, the subspecies M. quadrifasciata anthidioides and the two M. quadrifasciata populations with continuous metasomal stripes from northern Minas Gerais. These results confirmed that the yellow metasomal stripes alone are not a good means for correctly identifying the different subspecies of M. quadrifasciata.     

Long-term chromium picolinate supplementation improves colostrum profile of Santa Ines ewe

Biological Trace Element Research - Chromium (Cr) is a micromineral that is involved in the metabolism of carbohydrates, lipids, ammonia, and nucleic acids; thus, its supplementation can influence...     

Development of a novel anti-biofilm peptide derived from profilin of Spodoptera frugiperda

Abstract

Candida yeast infections are the fourth leading cause of death worldwide. Peptides with antimicrobial activity are a promising alternative treatment for such infections. Here, the antifungal activity of a new antimicrobial peptide—PEP-IA18—was evaluated against Candida species. PEP-IA18 was designed from the primary sequence of profilin, a protein from Spodoptera frugiperda, and displayed potent activity against Candida albicans and Candida tropicalis, showing a minimum inhibitory concentration (MIC) of 2.5?µM. Furthermore, the mechanism of action of PEP-IA18 involved interaction with the cell membrane (ergosterol complexation). Treatment at MIC and/or 10?×?MIC significantly reduced biofilm formation and viability. PEP-IA18 showed low toxicity toward human fibroblasts and only revealed hemolytic activity at high concentrations. Thus, PEP-IA18 exhibited antifungal and anti-biofilm properties with potential applicability in the treatment of infections caused by Candida species.     

In vivo antimalarial activity of novel 2-hydroxy-3-anilino-1,4-naphthoquinones obtained by epoxide ring-opening reaction

1,4-Naphthoquinone derivatives are known to have relevant activities against several parasites. Among the treatment options for malaria, atovaquone, a 1,4-naphthoquinone derivative, is widely applied in the treatment and prophylaxis of such disease. Based on the structure simplification of atovaquone, we designed and synthesized four novel naphthoquinoidal derivatives. The compounds were obtained by the underexplored epoxide-opening reaction of 1,4-naphthoquinone using aniline derivatives as nucleophiles. The antiplasmodial activity of the synthesized compounds was performed in vivo using Peter’s 4 days suppression test. Significant parasitemia reduction and increased survival were observed for some of the compounds.     

Life in Burrows Channelled the Morphological Evolution of the Skull in Rodents: the Case of African Mole-Rats (Bathyergidae,Rodentia)

African mole-rats are fossorial rodents that consist of five chisel-tooth digging genera (Heterocephalus, Heliophobius, Georychus, Fukomys, and Cryptomys) and one scratch digger (Bathyergus). They are characterized by striking physiological, morphological, and behavioral adaptations intimately related to their subterranean life. The influence of their mode of life in shaping the cranial morphology has yet to be evaluated in comparison to other Ctenohystrica, especially fossorial genera, which include the subterranean genera Spalacopus and Ctenomys. In our study, we seek to determine to what extent subterranean life affects the morpho-functional properties of the skull among fossorial ctenohystricans. 3D geometric morphometric analyses were performed on 277 skulls, encompassing 63 genera of Ctenohystrica, and complemented by biomechanical studies. African mole-rats and other subterranean Ctenohystrica, especially chisel-tooth diggers, have a short snout, a wide cranium with enlarged zygomatic arches, and a strongly hystricognathous mandible. Even if convergences are also manifest between most fossorial Ctenohystrica, subterranean rodents departed from the main ctenohystrican allometric trends in having a skull shape less size-dependent, but under stronger directional selection with intense digging activity as a major constraint. African mole-rats, notably chisel-tooth diggers, show important mechanical advantage for the temporalis muscles favoring higher forces at the bite point, while mechanical advantage of the superficial masseter muscles is lower compared to other Ctenohystrica. If subterranean species can be clearly discriminated based on their skull morphology, the intrinsic mosaic of anatomical characters of each genus (e.g., skull, teeth, and muscles) can be understood only in the light of their ecology and evolutionary history.