Multiple paternity and sperm competition in the sibling species Drosophila buzzatii and Drosophila koepferae

Sperm competition (SC) is a major component of sexual selection that enhances intra‐ and intersexual conflicts and may trigger rapid adaptive evolution of sexual characters. The actual role of SC on rapid evolution, however, is poorly understood. Besides, the relative contribution of distinctive features of the mating system to among species variation in the strength of SC remains unclear. Here, we assessed the strength of SC and mating system factors that may account for it in the closely related species Drosophila buzzatii and Drosophila koepferae. Our analyses reveal higher incidence of multiple paternity and SC risk in D. buzzatii wild‐inseminated females. The estimated number of fathers per brood was 3.57 in D. buzzatii and 1.95 in D. koepferae. In turn, the expected proportion of females inseminated by more than one male was 0.89 in D. buzzatii and 0.58 in D. koepferae. Laboratory experiments show that this pattern may be accounted for by the faster rate of stored sperm usage observed in D. koepferae and by the greater female remating rate exhibited by D. buzzatii. We also found that the male reproductive cost of SC is also higher in D. buzzatii. After a female mated with a second male, first‐mating male fertility was reduced by 71.4% in D. buzzatii and only 33.3% in D. koepferae. Therefore, we may conclude that postmating sexual selection via SC is a stronger evolutionary force in D. buzzatii than in its sibling.     

Commercial production of carrageenophytes in the Philippines: ensuring long-term sustainability for the industry

An abundance of marine algae along the Philippines' long, irregular coastline (36,289 km) has made it inevitable for Filipinos to exploit algae for food, feeds, medicine, or other purposes. Among the most popular of these algae are the carrageenophytes, which include four genera, six species, and 21 morphotypes/varieties/cultivars under the Family Solieriaceae. However, commercial production did not begin until 1973. The development of carrageenophyte farming for commercial purposes evolved from simple fixed-bottom monoline farming by coastal farmers, who refined the technology themselves, with the help and guidance of local and international scientists, which has led to a commercially viable industry with a maximum estimated production of 97,000–102,820 dry, metric tons in 2004. Farm gate revenues for that year were estimated at US$ 82.45–87.4 million (four croppings year^?1), whose main recipients were the local seaweed farmers. However, in 2008, production started to decline, which was brought primarily by the deteriorating quality of propagules and the perennial occurrence of “ice-ice” and harmful endophytes caused by environmental stresses due to unfavorable weather conditions, and secondarily, the peace and order problem in the major producing areas like Zamboanga, Maguindanao, Basilan, and Sulu in Mindanao and insufficient government support. This paper aims to assess the present situation and suggest how to possibly reverse the situation to its usual productive periods.     

RIG-I Detects Triphosphorylated RNA of Listeria monocytogenes during Infection in Non-Immune Cells

The innate immune system senses pathogens by pattern recognition receptors in different cell compartments. In the endosome, bacteria are generally recognized by TLRs; facultative intracellular bacteria such as Listeria, however, can escape the endosome. Once in the cytosol, they become accessible to cytosolic pattern recognition receptors, which recognize components of the bacterial cell wall, metabolites or bacterial nucleic acids and initiate an immune response in the host cell. Current knowledge has been focused on the type I IFN response to Listeria DNA or Listeria-derived second messenger c-di-AMP via the signaling adaptor STING. Our study focused on the recognition of Listeria RNA in the cytosol. With the aid of a novel labeling technique, we have been able to visualize immediate cytosolic delivery of Listeria RNA upon infection. Infection with Listeria as well as transfection of bacterial RNA induced a type-I-IFN response in human monocytes, epithelial cells or hepatocytes. However, in contrast to monocytes, the type-I-IFN response of epithelial cells and hepatocytes was not triggered by bacterial DNA, indicating a STING-independent Listeria recognition pathway. RIG-I and MAVS knock-down resulted in abolishment of the IFN response in epithelial cells, but the IFN response in monocytic cells remained unaffected. By contrast, knockdown of STING in monocytic cells reduced cytosolic Listeria-mediated type-I-IFN induction. Our results show that detection of Listeria RNA by RIG-I represents a non-redundant cytosolic immunorecognition pathway in non-immune cells lacking a functional STING dependent signaling pathway.     

Paleodistribution modeling suggests glacial refugia in Scandinavia and out‐of‐Tibet range expansion of the Arctic fox

Quaternary glacial cycles have shaped the geographic distributions and evolution of numerous species in the Arctic. Ancient DNA suggests that the Arctic fox went extinct in Europe at the end of the Pleistocene and that Scandinavia was subsequently recolonized from Siberia, indicating inability to track its habitat through space as climate changed. Using ecological niche modeling, we found that climatically suitable conditions for Arctic fox were found in Scandinavia both during the last glacial maximum (LGM) and the mid‐Holocene. Our results are supported by fossil occurrences from the last glacial. Furthermore, the model projection for the LGM, validated with fossil records, suggested an approximate distance of 2000 km between suitable Arctic conditions and the Tibetan Plateau well within the dispersal distance of the species, supporting the recently proposed hypothesis of range expansion from an origin on the Tibetan Plateau to the rest of Eurasia. The fact that the Arctic fox disappeared from Scandinavia despite suitable conditions suggests that extant populations may be more sensitive to climate change than previously thought.     

How do Different Types of Emulsifiers/Stabilizers Affect the In Vitro Intestinal Digestion of O/W Emulsions?

This study analyzes the influence of different types of molecules (tween, lecithin, xanthan gum, and methylcellulose) on the physical properties (flow behavior and particle size) and microstructure of oil-in-water (o/w) emulsions before and during in vitro intestinal digestion. The release of free fatty acids during a simulated intestinal stage has also been examined. The results show that various o/w emulsions present different rates and extents of lipolysis and that these differences are not primarily due to their rheological properties nor to the droplet size/surface area available for the action of lipase. Rather, the observed differences in the kinetics of lipolysis are most likely attributable to the nature and location of each type of molecule in their respective o/w emulsions as well as to their interactions with intestinal components. These results shed light on the mechanisms by which the interfacial layer controls lipid digestion, paving the way for a practical application of some of these emulsions in the production of foods used for regulating dietary lipid digestion in order to prevent and treat obesity and related disorders.

     

Taxonomy of the long‐tailed mouse Oligoryzomys destructor (Sigmodontinae: Oryzomyini) with the designation of neotypes for Hesperomys destructor Tschudi, 1844 and Hesperomys melanostoma Tschudi, 1844

The genus Oligoryzomys, distributed from southern South America to southern North America, is the most diverse of the tribe Oryzomyini of sigmodontine rodents. Even when 22 species are currently recognized, species boundaries are unclear for several forms. The species Oligoryzomys destructor is one of the least studied species of the genus and is the one with the largest distribution along the Andes (from southern Colombia to northern Bolivia). The species was described without the selection of a holotype and indication of its type locality. In addition, several taxa are regarded as synonyms of O. destructor. These facts are relevant because previous analysis of DNA sequences has shown that O. destructor represents a species complex. Herein, in addition to test the phylogenetic position of O. destructor within the genus Oligoryzomys, we assess patterns of morphological and molecular variation of O. destructor and its associated nominal forms aimed to assess the boundaries of the species. As part of the study, we selected neotypes for Hesperomys destructor and H. melanostoma. At the light of our results, we recognized O. destructor as a species with two subspecies, O. d. destructor and O. d. spodiurus. Also, we discuss the role of Andean rivers, and their different permeability, as allopatric barriers molding the structure of O. destructor.