Analysis of apoptosis and Bcl-2 expression in polar forms of leprosy

Apoptosis eliminates pathogen-infected cells. Its modulation can influence the course of infections, permitting the survival of intracellular pathogens. In leprosy, which presents several clinical manifestations related to bacillary burden and host immune status, the mechanisms responsible for the persistence of the bacillus are unknown. Few studies have focused on apoptosis over the disease spectrum and as a defense mechanism against Mycobacterium leprae. We evaluated apoptosis using terminal transferase dUTP nick end labeling and the expression of Bcl-2 by immunohistochemistry in skin lesions from 11 tuberculoid and 15 lepromatous leprosy patients. Each specimen was evaluated by determining the number of positive cells in 10 fields at × 400 magnification. We observed a higher number of apoptotic cells in tuberculoid lesions in comparison with lepromatous leprosy (42.5 cells per 10 fields vs. 11.5 cells per 10 fields, P<0.0001). Expression of Bcl-2, conversely, was larger in lepromatous than in tuberculoid samples (172.0 cells per 10 fields vs. 17.7 cells per 10 fields, P<0.0001). These observations suggest modulation of apoptosis in leprosy, primarily in lepromatous patients, for which the decrease in cell death could support M. leprae survival and contribute to the success of infection. Conversely, in tuberculoid patients, apoptosis could contribute to reducing propagation of the bacillus.     

Predominance of single paternity in the black spiny-tailed iguana: conservation genetic concerns for female-biased hunting

Because of female-biased illegal harvesting, knowledge about the genetic mating system of the black spiny-tailed iguana Ctenosaura pectinata is of primary interest for the conservation of this threatened species. Based on the high levels of multiple paternity found in clutches of many other reptiles, particularly in lizards, it is hypothesised that multiple paternity may also be common in black iguanas. This was investigated by using microsatellite DNA to estimate the number of males siring nine litters (9 mothers, 121 offspring genotyped at ten polymorphic loci) of black iguanas. Contrary to expectations, only 11% of sampled black iguana females produced litters consistent with being sired by multiple males. These data are the first evidence for the predominance of single paternity within an iguanid lizard, and suggest that black iguana may be more susceptible to loss of genetic variation in the face of gender-biased over-hunting pressure than previously thought.     

Ultrastructural changes in skeletal muscle of the tail of the lizard Hemidactylus mabouia immediately following autotomy

Araújo, T.H., Faria, F.P., Katchburian, E. and Freymüller, E. (2009). Ultrastructural changes in skeletal muscle of the tail of the lizard Hemidactylus mabouia immediately following autotomy. —Acta Zoologica (Stockholm) 91 : 440–446. Although autotomy and subsequent regeneration of lizard tails has been extensively studied, there is little information available on ultrastructural changes that occur to the muscle fibers at the site of severance. Thus, in the present study, we examine the ultrastructure of the musculature of the remaining tail stump of the lizard Hemidactylus mabouia immediately after autotomy. Our results show that exposed portions of the skeletal muscle fibers of the stump that are unprotected by connective tissue bulge to produce large mushroom‐like protrusions. These exposed portions show abnormal structure but suffer no leakage of cytoplasmic contents. Many small and large vesicular structures appeared between myofibrils in the interface at this disarranged region (distal) and the other portion of the fibers that remain unchanged (proximal). These vesicles coalesce, creating a gap that leads to the release of the mushroom‐like protrusion. So, our results showed that after the macroscopic act of autotomy the muscular fibers release part of the sarcoplasm as if a second and microscopic set of autotomic events takes place immediately following the macroscopic act of autotomy. Presumably these changes pave the way for the formation of a blastema and the beginning of regeneration.     

Morphology and development of additional bony elements in the genus Brachycephalus (Anura: Brachycephalidae)

We describe the extra bony elements, plates, and osteoderms present in species of the genus Brachycephalus. Samples of eight species of Brachycephalus, including seven populations of Brachycephalus ephippium, were examined. The large additional elements associated with the skull (parotic plate) and vertebrae (vertebral and paravertebral plates) all comprise intramembranous bone, similar to that of the frontoparietal or nasal bones of the skull of most of frogs. Additionally, in the dermis of one unnamed species, we discovered and described true osteoderms. We discuss the morphological nature and diversity of theses elements and their importance as evidence of phylogenetic relationship within Brachycephalus. In summary, three distinct conditions of extra bony elements occur in the genus Brachycephalus: (1) bony plates may be present or absent in species of the genus; (2) a few, small bony plates may be developed and these may be represented by (a) paravertebral plates small and restricted to the distal ends of the transverse processes of the presacral IV, (b) parotic plates small and not covering the tops of the squamosals, and (c) ornamented spinal plates on all vertebrae; and (3) well‐developed bony plates may be present as (a) paravertebral plates forming a ‘bone‐shield’ on the dorsal surface of the trunk, ornamented, and visible through the integument, (b) parotic plates covering the tops of the squamosals, and (c) spinal plates associated with all vertebrae, and ornamented on vertebrate I–VI. Although the phenomenon of miniaturization may be associated with the appearance of new elements in at least some of the species in the genus, the traditional rule may not be universally applicable. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 752–767.     

Morphological and molecular taxonomy of a new Daptonema (Nematoda,Xyalidae) with comments on the systematics of some related taxa

A new species of Daptonema is described based upon morphological characters and 18S rRNA sequence. Daptonema matrona sp. nov. was collected in Pina Basin (north‐eastern Brazil). It differs from all other species of the genus by the presence of reduced cephalic setae and straight spicules. These features require an adaptation of the generic diagnosis. Moreover, the females are characterized by intra‐uterine development of the offspring, considered herein as their major autapomorphic feature. Molecular systematic analyses supported Daptonema matrona sp. nov. as a distinct genetic and evolutionary lineage. The data also indicate hypotheses of taxonomic synonymies amongst some related taxa from Xyalidae as well as the paraphyly of Daptonema. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 1–15.     

Karyotype analysis in South American species of Myrtaceae

In Myrtaceae (Myrteae), the diploid chromosome number 2 n  = 2 x  = 22 is the most common, although variations of ploidy level occur, with some triploid (2 n  = 3 x  = 33) and tetraploid (2 n  = 4 x  = 44) records. Karyotype details in this group are scarce because the chromosomes are small (< 2 μm). In this work, we carried out a karyotypic analysis of 15 species of Myrtaceae grouped in different subtribes and genera. Measurements of chromosome length (long arm, L ; short arm, S ) were taken and several karyotypic parameters were calculated for each species. The karyotypes in fleshy-fruited taxa (Myrteae) were more varied than in the other previously analysed dry-fruited group ( Eucalyptus , Eucalypteae), in which the chromosomes were exclusively metacentric.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155 , 571–580.     

Microhabitat selection by ant-lion larvae Myrmeleon brasiliensis (Návas) (Neuroptera: Myrmeleontidae), in a Forest Reserve, Aquidauana, State of Mato Grosso do Sul

The relative abundance, density, distribution pattern and relation among pit diameter and larvae body size of Myrmeleon brasiliensis Návas were evaluated in two microhabitats: sheltered and exposed. The total of 282 pits were found in sheltered microhabitat and only 50 in the exposed. The density of M. brasiliensis was between one and 43 individuals per m(2). The distribution pattern of larvae tended from pooled to regular distribution as the density increased. In both microhabitats the larvae body size was positively correlated with pit diameter.