Roosting Requirements of Two Frugivorous Bats (Sturnira lilium and Arbiteus intermedius) in Fragmented Neotropical Forest1

As tropical forest fragmentation accelerates, scientists are concerned with the loss of species, particularly those that play important ecological roles. Because bats play a vital role as the primary seed dispersers in cleared areas, maintaining healthy bat populations is critical to natural forest regeneration. Observations of foraging bats suggest that many Neotropical fruit‐eating species have fairly general habitat requirements and can forage in many different kinds of disturbed vegetation; however, their roosting requirements may be quite different. To test whether or not general foraging requirements are matched by equally broad roosting requirements, we used radiotelemetry to locate roost sites of two common frugivorous bat species (Sturnira lilium and Artibeus intermedius) in a fragmented forest in southeastern Mexico. Sturnira lilium roosted inside tree cavities and selected large‐diameter roost trees in remnant patches of mature forest. Fewer than 2 percent of trees surveyed had a mean diameter equal to or greater than roost trees used by . S. lilium, Artibeus intermedius roosted externally on branches and vines and under palm leaves and selected roost trees of much smaller diameter. Compared to random trees, roost trees chosen by A. intermedius were closer to neighboring taller trees and also closer in height to these trees. Such trees likely provide cryptic roosts beneath multiple overlapping crowns, with sufficient shelter from predators and the elements. While males of A. intermedius generally roosted alone in small trees within secondary forest, females roosted in small groups in larger trees within mature forest and commuted more than three times farther than males to reach their roost sites. Loss of mature forest could impair the ability of frugivorous bats to locate suitable roost sites. This could have a negative impact on bat populations, which in turn could decrease forest regeneration in impacted areas.     

Activin promotes oocyte development in ovine preantral follicles <Emphasis Type="Italic">in vitro</Emphasis>

Activins have been implicated as important regulating factors for many reproductive processes. The aim of this study was to determine the effect of activin A on the development of ovine preantral follicles in vitro. Mechanically isolated preantral follicles (161 ± 2 microm) were cultured for 6 days in the presence of human recombinant activin A (0, 10 and 100 ng/ml). Half of the medium was replaced every second day and follicle diameters were measured. Conditioned medium was subsequently analysed for oestradiol content using a delayed enhancement lanthanide fluorometric immunoassay (DELFIA). At the end of the culture period, follicles were fixed and processed for histology, after which oocyte diameter and granulosa cell death were measured. There was significant follicle growth over 6 days in all groups (p < 0.001). Activin, at both concentrations, increased follicle growth over control levels by Day 6 (p < 0.05). Oocyte diameters were also significantly increased by Day 6 of culture in all groups (p < 0.05), with 100 ng/ml activin increasing oocyte diameter over control levels (p < 0.05). Activin, at both concentrations, increased oestradiol production on Day 2 of culture, but this increase was not sustained during the culture period. Moreover, activin did not have any effect on antrum formation or follicle survival. In conclusion, activin promoted ovine preantral follicle and oocyte growth in vitro, but did not accelerate follicle differentiation over a six-day culture period. These results support a paracrine role for activin A during early oocyte and follicular development.     

Adenovirus efficiently transduces plasmacytoid dendritic cells resulting in TLR9-dependent maturation and IFN-alpha production

BACKGROUND: Recombinant replication-deficient adenoviral vectors (recAd) are attractive candidates for DNA vaccination approaches because they are able to activate the innate and adaptive immune systems. Here we explore the ability of recAd to transduce and activate subsets of dendritic cells, namely plasmacytoid dendritic cells (pDC) and conventional dendritic cells (cDC). METHODS: DC were derived from bone marrow precursors in vitro with the help of FLT3-ligand. Sorted populations of pDC and cDC were infected with recAd at various multiplicities of infection. Transduction efficiency, phenotypic maturation and production of IFN-alpha as well as IL-6 were assessed. Additionally, activation of DC and induction of cytotoxic T lymphocytes (CTL) were determined in vivo. The role of Toll-like receptor (TLR) 9 in recAd recognition was investigated as it has previously been shown that DNA viruses are recognized via this receptor. RESULTS: RecAd can efficiently transduce pDC as well as cDC in vitro. Both DC subsets mature and produce IFN-alpha upon interaction with recAd. In the absence of TLR9, activation and cytokine production was only detected in cDC but not in pDC. Importantly, induction of CD8+ CTL following in vivo injection of recAd was similar in TRL9-deficient mice when compared with wildtype controls. CONCLUSIONS: RecAd can efficiently transduce and activate both pDC and cDC. pDC required TLR9 to detect the presence of recAd whereas cDC also recognized recAd independently of TLR9. These unique immunostimulatory properties support the future development of recombinant Ad as a vector for DNA vaccine approaches.     

Passive serum therapy with polyclonal antibodies against Mycobacterium tuberculosis protects against post-chemotherapy relapse of tuberculosis infection in SCID mice

We investigated the protective role of immune-sera against reactivation of Mycobacterium tuberculosis infection in SCID mice and found that passive immunization with sera obtained from mice treated with detoxified M. tuberculosis extracts (delivered in liposomes in a composition known as RUTI) exerted significant protection. Our SCID mouse model consisted of aerosol infection by M. tuberculosis, followed by 3 to 8weeks of chemotherapy with isoniazid+rifampicin (INH+RIF) (25 and 10mg/kg, respectively). After infection and antibiotic administration, two groups of mice were treated for up to 10weeks with intraperitoneal passive immunization using hyperimmune serum (HS) obtained from mice infected with M. tuberculosis, treated with chemotherapy (INH+RIF) for 8weeks and inoculated with RUTI (HS group) or with normal serum (CT group). Significant differences were found between HS and CT groups in the number of bacilli in the lungs (3.68+/-2.02 vs. 5.72+/-1.41log(10) c.f.u.), extent of pulmonary granulomatomous infiltration (10.33+/-0.67 vs. 31.2+/-1.77%), and percentage of animals without pulmonary abscesses (16.7% vs. 45.5%). These data strongly suggest a protective role of specific antibodies against lung dissemination of M. tuberculosis infection.     

Conventional kinesin holoenzymes are composed of heavy and light chain homodimers

Conventional kinesin is a major microtubule-based motor protein responsible for anterograde transport of various membrane-bounded organelles (MBO) along axons. Structurally, this molecular motor protein is a tetrameric complex composed of two heavy (kinesin-1) chains and two light chain (KLC) subunits. The products of three kinesin-1 (kinesin-1A, -1B, and -1C, formerly KIF5A, -B, and -C) and two KLC (KLC1, KLC2) genes are expressed in mammalian nervous tissue, but the functional significance of this subunit heterogeneity remains unknown. In this work, we examine all possible combinations among conventional kinesin subunits in brain tissue. In sharp contrast with previous reports, immunoprecipitation experiments here demonstrate that conventional kinesin holoenzymes are formed of kinesin-1 homodimers. Similar experiments confirmed previous findings of KLC homodimerization. Additionally, no specificity was found in the interaction between kinesin-1s and KLCs, suggesting the existence of six variant forms of conventional kinesin, as defined by their gene product composition. Subcellular fractionation studies indicate that such variants associate with biochemically different MBOs and further suggest a role of kinesin-1s in the targeting of conventional kinesin holoenzymes to specific MBO cargoes. Taken together, our data address the combination of subunits that characterize endogenous conventional kinesin. Findings on the composition and subunit organization of conventional kinesin as described here provide a molecular basis for the regulation of axonal transport and delivery of selected MBOs to discrete subcellular locations.     

Do you do text?

Retrieving information from text has become an important areain bioinformatics, and not too surprisingly, this journal haspublished more than 30 papers on this topic since the firstarticle published by the journal in 1998. In addition, ISCB(International Society for Computational Biology) (www.iscb.org)has organized special sessions in the ISMB conferences (IntelligentSystems for Molecular Biology, see www.iscb.org/ismb2005) anda specialized interest group (www.pdg.cnb.uam.es/BioLink/) forthe last five years. In parallel, major computer science conferencesin related areas have begun     

Ultraviolet photoproducts at the ochre suppressor mutation site in the glnU gene of Escherichia coli: relevance to "mutation frequency decline"

Summary Ochre suppressor mutations induced by UV in the Escherichia coli glnU tRNA gene are CG to TA transitions at the first letter of the anticodon-encoding triplet, CAA. Premutational UV photoproducts at this site have long been known to exhibit an excision repair anomaly (mutation frequency decline or MFD), whereby post-irradiation inhibition of protein synthesis enhances their excision and reduces suppressor mutation yields ten-fold. We sought to clarify the basis of this unique repair response by determining the spectrum of UV photoproducts on both strands of a 36 by region of glnU which includes the anticodon-encoding triplet. We found that four different photolesions are produced within the 3 by sequence corresponding to the tRNA anticodon: (i) on the transcribed strand, TC (6–4) photoproducts and TC cyclobutane dimers are formed in equal numbers at the site of the C to T transition, indicating that this site is a hotspot for the usually less frequent (6–4) photoproduct; (ii) on the nontranscribed strand, TT dimers are found opposite the second and third letters of the anticodon-encoding triplet, adjacent to the mutation site; and (iii) on the nontranscribed strand, an alkali-sensitive lesion other than a (6–4) photoproduct is formed, apparently at the G in the mutation site. We suggest that mutation frequency decline may reflect excision repair activity at closely spaced UV lesions on opposite strands, resulting in double-strand breaks and the death of potential mutants.     

Enhanced resistance to two stem borers in an aromatic rice containing a synthetic cryIA(b) gene

Rice cultivars of isozyme group V include high-quality, aromatic rices that are difficult to improve by traditional methods because of the loss of quality characters upon sexual hybridization. Their low-tillering plant type predisposes them to economic loss from attack by stem borers, a group of insects to which they are susceptible. We report here the enhancement of stem borer resistance in cv. Tarom Molaii through transformation by microprojectile bombardment. Embryogenic calli derived from mature seeds were bombarded with gold particles coated with plasmid pCIB4421, carrying a synthetic truncated toxin gene based on the cryIA(b) gene from Bacillus thuringiensis, and plasmid pHygII, carrying the hygromycin phosphotransferase (hpt) selectable marker gene. Inclusion of 50 mg/l hygromycin B in culture media from bombardment through to rooting of plantlets eliminated escapes. The procedure generated three independent hpt transformants of which two also contained the cryIA(b) gene. One such line (No. 827) produced truncated (67 kDa) CryIA(b) protein equivalent to about 0.1% of total soluble protein. The cryIA(b) gene was controlled by the promoter of the maize C₄ PEP carboxylase gene and was expressed in leaf blades but was not expressed to a detectable level in dehulled mature grain. Line 827 contained about 3 copies of the cryIA(b) gene which segregated as a single dominant Mendelian locus in the second (T₁) and third (T₂) generations and co-segregated with enhanced resistance to first-instar larvae of striped stem borer (Chilo suppressalis) and yellow stem borer (Scirpophaga incertulas). T₂ line 827-6 homozygous for the cryIA(b) gene showed no dead hearts or whiteheads after infestation with stem borers, whereas T₂ line 827-25 lacking the gene averaged 7 dead hearts per plant and 2.25 whiteheads per plant. These results establish that transformation of high-quality rices of group V is a feasible alternative to sexual hybridization.