Population dynamics, reproduction, and diet of the lesser long-nosed bat (Leptonycteris curasoae) in Jalisco, Mexico: implications for conservation

We estimate fluctuations in population size and sex ratio, documentbreeding behavior and reproduction, and determine the diet of a population ofthe lesser long-nosed bat, Leptonycteris curasoae, in anisland cave in Chamela Bay, Jalisco, Mexico, with monthly sampling during anannual cycle (October 1999–October 2000). Based on the area of thecave's ceiling and wall covered with L. curasoae inrelation to the potential roost area without them, in 1999 the abundanceincreased from 80% in October to 100% in November and December. In 2000 thepopulation decreased to 80% in January, 50% in February, 30% in March, 20% inApril, 10% in May, 5% in June and July, and less than 1% in August. Thepopulation rapidly increased to 60% in September and to 80% in October.Throughout the year there were significantly more males than females; however,there was significant heterogeneity over months. In September–Novemberthere were more females, but in December–August there were more malespresent. The majority of pregnant and lactating females were observed fromDecember to March and in July, while males were reproductive fromSeptember–January and in May–June. Breeding activity was observed inthe cave in November–December. Twenty-six species of plants were consumedduring the year, based on pollen identification from fecal samples. Bombacaceousspecies were the most important component of the diet from January to May andCactaceae were most important in June–September. Peak abundance and reproductive activitycoincided with peak flower resource availability, which occurred between Octoberand January and in June–July. The year-round presence and reproductiveactivity of L. curasoae at this site throughout the yeardemonstrate that many individuals are annual residents in this area and indicatethe importance of this roosting site. In order to develop a successfulconservation program for L. curasoae, in addition toprotecting migratory corridors and northern maternity roosts, it is equallyimportant to identify and protect areas that function as breeding colonies andyear-round sanctuaries for resident populations in the south.     

Home Range Size and Use in Allocebus trichotis in Analamazaotra Special Reserve, Central Eastern Madagascar

No information is currently available on the space needs of hairy-eared dwarf lemurs (Allocebus trichotis), classified as Data Deficient. The data are crucial for their conservation and comparison with other nocturnal primates. I conducted the first radiotracking study of the species from January to December 2007 in the Analamazaotra Special Reserve of Central Eastern Madagascar. I used nocturnal focal individual follows and daytime nest locations to determine home ranges. I followed 1 full sleeping group (4 adults) for 8 mo and 1 partial sleeping group (2 females) for 3 mo. Group home ranges, calculated via 100% minimum convex polygons (MCP), were 35.5 ha and 16.0 ha, respectively. The 95% kernel method of analysis yielded group home ranges of 15.2 ha and 7.1 ha respectively. The mean home range size for individuals was 15.4 ha (MCP) and 5.4 ha (kernel). This is much larger than for other Cheirogaleidae and could be due to a more insectivorous diet or the use of patchily distributed gum-producing trees. There were small nonsignificant monthly variations in home range size. The mean home range size per individual per month was 5.2 ha (MCP) and 2.2 ha (kernel). Important individual differences in overall and monthly home range size could be due to variations in the individual reproductive cycles and survival strategies. Overlap analyses and the lack of sexual difference in home range size suggest the social unit is a family or multimale/multifemale sleeping group with monogamous or promiscuous mating. The Analamazaotra Special Reserve probably holds ca. 100 adult individuals. Additional research is urgently needed to clarify the habitat needs of this rare species.     

Effect of interleukin-1β on spinal cord nociceptive transmission of normal and monoarthritic rats after disruption of glial function

Introduction  

Cytokines produced by spinal cord glia after peripheral injuries have a relevant role in the maintenance of pain states. Thus, while IL-1β is overexpressed in the spinal cords of animals submitted to experimental arthritis and other chronic pain models, intrathecal administration of IL-1β to healthy animals induces hyperalgesia and allodynia and enhances wind-up activity in dorsal horn neurons.     

Recent Rapid Rise of a Permethrin Knock Down Resistance Allele in Aedes aegypti in México

Background

Aedes aegypti, the ‘yellow fever mosquito’, is the primary vector to humans of dengue and yellow fever flaviviruses (DENV, YFV), and is a known vector of the chikungunya alphavirus (CV). Because vaccines are not yet available for DENV or CV or are inadequately distributed in developing countries (YFV), management of Ae. aegypti remains the primary option to prevent and control outbreaks of the diseases caused by these arboviruses. Permethrin is one of the most widely used active ingredients in insecticides for suppression of adult Ae. aegypti. In 2007, we documented a replacement mutation in codon 1,016 of the voltage-gated sodium channel gene (para) of Ae. aegypti that encodes an isoleucine rather than a valine and confers resistance to permethrin. Ile1,016 segregates as a recessive allele conferring knockdown resistance to homozygous mosquitoes at 5–10 µg of permethrin in bottle bioassays.

Methods and Findings

A total of 81 field collections containing 3,951 Ae. aegypti were made throughout México from 1996 to 2009. These mosquitoes were analyzed for the frequency of the Ile1,016 mutation using a melting-curve PCR assay. Dramatic increases in frequencies of Ile1,016 were recorded from the late 1990''s to 2006–2009 in several states including Nuevo León in the north, Veracruz on the central Atlantic coast, and Yucatán, Quintana Roo and Chiapas in the south. From 1996 to 2000, the overall frequency of Ile1,016 was 0.04% (95% confidence interval (CI95) = 0.12%; n = 1,359 mosquitoes examined). The earliest detection of Ile1,016 was in Nuevo Laredo on the U.S. border in 1997. By 2003–2004 the overall frequency of Ile1,016 had increased ∼100-fold to 2.7% (±0.80% CI95; n = 808). When checked again in 2006, the frequency had increased slightly to 3.9% (±1.15% CI95; n = 473). This was followed in 2007–2009 by a sudden jump in Ile1,016 frequency to 33.2% (±1.99% CI95; n = 1,074 mosquitoes). There was spatial heterogeneity in Ile1,016 frequencies among 2007–2008 collections, which ranged from 45.7% (±2.00% CI95) in the state of Veracruz to 51.2% (±4.36% CI95) in the Yucatán peninsula and 14.5% (±2.23% CI95) in and around Tapachula in the state of Chiapas. Spatial heterogeneity was also evident at smaller geographic scales. For example within the city of Chetumal, Quintana Roo, Ile1,016 frequencies varied from 38.3%–88.3%. A linear regression analysis based on seven collections from 2007 revealed that the frequency of Ile1,016 homozygotes accurately predicted knockdown rate for mosquitoes exposed to permethrin in a bioassay (R² = 0.98).

Conclusions

We have recorded a dramatic increase in the frequency of the Ile1,016 mutation in the voltage-gated sodium channel gene of Ae. aegypti in México from 1996 to 2009. This may be related to heavy use of permethrin-based insecticides in mosquito control programs. Spatial heterogeneity in Ile1,016 frequencies in 2007 and 2008 collections may reflect differences in selection pressure or in the initial frequency of Ile1,016. The rapid recent increase in Ile1,016 is predicted by a simple model of positive directional selection on a recessive allele. Unfortunately this model also predicts rapid fixation of Ile1,016 unless there is negative fitness associated with Ile1,016 in the absence of permethrin. If so, then spatial refugia of susceptible Ae. aegypti or rotational schedules of different classes of adulticides could be established to slow or prevent fixation of Ile1,016.     

Enzymatic and nonenzymatic functions of viral RNA-dependent RNA polymerases within oligomeric arrays

Few antivirals are effective against positive-strand RNA viruses, primarily because the high error rate during replication of these viruses leads to the rapid development of drug resistance. One of the favored current targets for the development of antiviral compounds is the active site of viral RNA-dependent RNA polymerases. However, like many subcellular processes, replication of the genomes of all positive-strand RNA viruses occurs in highly oligomeric complexes on the cytosolic surfaces of the intracellular membranes of infected host cells. In this study, catalytically inactive polymerases were shown to participate productively in functional oligomer formation and catalysis, as assayed by RNA template elongation. Direct protein transduction to introduce either active or inactive polymerases into cells infected with mutant virus confirmed the structural role for polymerase molecules during infection. Therefore, we suggest that targeting the active sites of polymerase molecules is not likely to be the best antiviral strategy, as inactivated polymerases do not inhibit replication of other viruses in the same cell and can, in fact, be useful in RNA replication complexes. On the other hand, polymerases that could not participate in functional RNA replication complexes were those that contained mutations in the amino terminus, leading to altered contacts in the folded polymerase and mutations in a known polymerase–polymerase interaction in the two-dimensional protein lattice. Thus, the functional nature of multimeric arrays of RNA-dependent RNA polymerase supplies a novel target for antiviral compounds and provides a new appreciation for enzymatic catalysis on membranous surfaces within cells.     

Papillomavirus particles assembled in 293TT cells are infectious in vivo

Papillomaviruses (PVs) demonstrate both tissue and species tropisms. Because PVs replicate only in terminally differentiating epithelium, the recent production of infectious PV particles in 293 cells marks an important breakthrough. In this article, we demonstrate that infectious PV particles produced in 293TT cells can cause papillomatous growths in the natural host animal. Moreover, we show that species-matched PV genomes can be successfully delivered in vivo by a heterologous, species-mismatched PV capsid. Additionally, our results indicate that the addition of the simian virus 40 origin of replication to the papillomavirus genome increases the production of infectious papillomavirus particles by increasing genome amplification in the transfected 293TT cells.