Simultaneously hermaphroditic shrimp use lipophilic cuticular hydrocarbons as contact sex pheromones

Successful mating is essentially a consequence of making the right choices at the correct time. Animals use specific strategies to gain information about a potential mate, which is then applied to decision-making processes. Amongst the many informative signals, odor cues such as sex pheromones play important ecological roles in coordinating mating behavior, enabling mate and kin recognition, qualifying mate choice, and preventing gene exchange among individuals from different populations and species. Despite overwhelming behavioral evidence, the chemical identity of most cues used in aquatic organisms remains unknown and their impact and omnipresence have not been fully recognized. In many crustaceans, including lobsters and shrimps, reproduction happens through a cascade of events ranging from initial attraction to formation of a mating pair eventually leading to mating. We examined the hypothesis that contact pheromones on the female body surface of the hermaphroditic shrimp Lysmata boggessi are of lipophilic nature, and resemble insect cuticular hydrocarbon contact cues. Via chemical analyses and behavioural assays, we show that newly molted euhermaphrodite-phase shrimp contain a bouquet of odor compounds. Of these, (Z)-9-octadecenamide is the key odor with hexadecanamide and methyl linoleate enhancing the bioactivity of the pheromone blend. Our results show that in aquatic systems lipophilic, cuticular hydrocarbon contact sex pheromones exist; this raises questions on how hydrocarbon contact signals evolved and how widespread these are in the marine environment.     

Report of the 2006 RSPCA/UFAW Rodent Welfare Group meeting

The RSPCA/UFAW Rodent Welfare Group holds a one-day meeting every autumn to discuss current welfare research and to exchange views on rodent welfare issues. A key aim of the group is to encourage people to think about the lifetime experience of laboratory rodents, ensuring that every potential influence on their well-being has been reviewed and refined. Speakers at the 2006 meeting presented preliminary findings of ongoing studies and discussed regulatory updates. Topics included the housing and husbandry of mice and rats, refining the use of rodents in asthma research, good practice for the euthanasia of rodents using carbon dioxide and achieving reduction by sharing genetically modified mice.     

Coral settlement onto Halimeda opuntia: a fatal attraction to an ephemeral substrate?

Degraded reefs with a high abundance of macroalgae usually also have low densities of coral recruits. Few studies, however, have examined whether these algae affect coral larval settlement. This study demonstrates, experimentally, that larvae of the Caribbean coral Favia fragrum can settle on the green alga Halimeda opuntia even when another substrate more suitable for settlement is present. Larval settlement onto experimental substrates was quantified under three treatments: rubble only, rubble plus plastic algal mimic, and rubble plus live H. opuntia. Similar total larval settlement was observed in all treatments. No larvae settled on the algal mimic, but total settlement was similar on the rubble in the first two treatments, showing that the rubble alone offered sufficient substrate for high settlement success. About half the larvae in the live algal treatment settled on H. opuntia instead of on the rubble, showing that larvae did not reject this substrate as they did the algal mimic. This result raises the possibility that corals will settle on some macroalgae when their abundance is high. Most macroalgae, including H. opuntia, are ephemeral substrates unsuitable for post-settlement survival. Such unexpected settlement may therefore have significant consequences for coral recruitment success on algal-dominated reefs.     

Purification and characterization of a thermostable chitinase from <Emphasis Type="Italic">Bacillus licheniformis</Emphasis> Mb-2

Summary A chitinase produced by Bacillus licheniformis MB-2 isolated from Tompaso geothermal springs, Indonesia, was purified and characterized. The extracellular enzyme was isolated by successive hydrophobic interaction, anion exchange, and gel filtration chromatographies. The purified enzyme was a monomer with an apparent molecular weight of 67 kDa. The optimal temperature and pH of the enzyme were 70 °C and 6.0, respectively. It was stable below 60 °C for 2 h and over a broad pH range of 4.0–11.0 for 4 h. The enzyme was resistant to denaturation by urea (1 M), Tween-20 (1%) and Triton-X (1%), but unstable toward organic solvents such as dimethyl sulphoxide, DMSO, (5%) and polyethylene glycol, PEG, (5%) for 30 min. The enzyme hydrolysed colloidal chitin, glycol chitin, chitosan, and glycol chitosan. The first 13 N-terminal amino acids of the enzyme were determined as SGKNYKIIGYYPS, which is identical to those in chitinases from B. licheniformis and B. circulans.     

Down-regulation of Notch target gene expression by Suppressor of deltex

In Drosophila, Suppressor of deltex (Su(dx)) mutations display a wing vein gap phenotype resembling that of Notch gain of function alleles. The Su(dx) protein may therefore act as a negative regulator of Notch but its activity on actual Notch signalling levels has not been demonstrated. Here we show that Su(dx) does regulate the level of Notch signalling in vivo, upstream of Notch target genes and in different developmental contexts, including a previously unknown role in leg joint formation. Overexpression of Su(dx) was capable of blocking both the endogenous activity of Notch and the ectopic Notch signalling induced by the overexpression of Deltex, an intracellular Notch binding protein. In addition, using the conditional phenotype of the Su(dx)(sp) allele, we show that loss of Su(dx) activity is rapidly followed by an up-regulation of E(spl)mbeta expression, the immediate target of Notch signal activation during wing vein development. While Su(dx) adult wing vein phenotypes are quite mild, only affecting the distal tips of the veins, we show that the initial consequence of loss of Su(dx) activity is more severe than previously thought. Using a time-course experiment we show that the phenotype is buffered by feedback regulation illustrating how signalling networks can make development robust to perturbation.     

Drosophila deltex mediates suppressor of Hairless-independent and late-endosomal activation of Notch signaling

Notch (N) signaling is an evolutionarily conserved mechanism that regulates many cell-fate decisions. deltex (dx) encodes an E3-ubiquitin ligase that binds to the intracellular domain of N and positively regulates N signaling. However, the precise mechanism of Dx action is unknown. Here, we found that Dx was required and sufficient to activate the expression of gene targets of the canonical Su(H)-dependent N signaling pathway. Although Dx required N and a cis-acting element that overlaps with the Su(H)-binding site, Dx activated a target enhancer of N signaling, the dorsoventral compartment boundary enhancer of vestigial (vgBE), in a manner that was independent of the Delta (Dl)/Serrate (Ser) ligands- or Su(H). Dx caused N to be moved from the apical cell surface into the late-endosome, where it accumulated stably and co-localized with Dx. Consistent with this, the dx gene was required for the presence of N in the endocytic vesicles. Finally, blocking the N transportation from the plasma membrane to the late-endosome by a dominant-negative form of Rab5 inhibited the Dx-mediated activation of N signaling, suggesting that the accumulation of N in the late-endosome was required for the Dx-mediated Su(H)-independent N signaling.     

Oxidative metabolic profiles of Brucella strains isolated from marine mammals: contribution to their species classification

Since the 1990s, Brucella strains not matching the characteristics of any of the six conventional species have been isolated worldwide from marine mammals. In this study, 31 Brucella strains isolated from various marine mammals were examined for their oxidative metabolic pattern on 12 amino-acid and carbohydrate substrates. Three main oxidative profiles different from those of the Brucella terrestrial mammal strains were identified for the marine mammal strains: one gathering strains isolated from pinnipeds and two gathering strains from cetaceans. Thus, both oxidative metabolism results and previous molecular studies are in agreement with the proposal of two new Brucella species, Brucella pinnipediae and Brucella cetaceae, to classify the Brucella strains isolated from marine mammals, and are also in accordance with a classification of species of the Brucella genus based on host preference.     

Evaluation of Brucella MLVA typing for human brucellosis

Human brucellosis is still the most common bacterial zoonosis worldwide. Neither well-known molecular tools nor the classical biotyping methods are satisfactory for subtyping of Brucella spp. Loci containing Variable Number of Tandem Repeats (VNTRs) have recently proved their usefulness in typing strains from animal origin despite the high genetic homogeneity within the genus Brucella (DNA-DNA homology >90%). The aim of this study was to evaluate MLVA (Multiple Locus VNTR Analysis) for diagnostic and epidemiological use in human brucellosis. One hundred and twenty-eight B. melitensis isolates of all three biovars were typed using eight minisatellite (panel 1) and eight microsatellite (panel 2) markers. One hundred and ten different genotypes were identified. The MLVA clustering pattern correlated with the geographic origin of the strains. Brucella strains isolated from different patients within the same outbreak or from the same patient before first-line therapy and after relapse showed identical genotypes. Fuchsin sensitive B. melitensis strains were found in closely related clusters giving evidence for an association between VNTRs and some phenotypic characteristics. However, the validity of biovars established by classical microbiological methods could not be confirmed by MLVA clustering. The original data can be queried on the genotyping web page at http://bacterial-genotyping.igmors.u-psud.fr. The MLVA assay is rapid, highly discriminatory, and reproducible within human Brucella isolates. MLVA can significantly contribute to epidemiological trace-back analysis of Brucella infections and may advance surveillance and control of human brucellosis.     

The application of spectroscopy techniques for diagnosis of malaria parasites and arboviruses and surveillance of mosquito vectors: A systematic review and critical appraisal of evidence

Spectroscopy-based techniques are emerging diagnostic and surveillance tools for mosquito-borne diseases. This review has consolidated and summarised recent research in the application of Raman and infrared spectroscopy techniques including near- and mid-infrared spectroscopy for malaria and arboviruses, identified knowledge gaps, and recommended future research directions. Full-length peer-reviewed journal articles related to the application of Raman and infrared (near- and mid-infrared) spectroscopy for malaria and arboviruses were systematically searched in PUBMED, MEDILINE, and Web of Science databases using the PRISMA guidelines. In text review of identified studies included the methodology of spectroscopy technique used, data analysis applied, wavelengths used, and key findings for diagnosis of malaria and arboviruses and surveillance of mosquito vectors. A total of 58 studies met the inclusion criteria for our systematic literature search. Although there was an increased application of Raman and infrared spectroscopy-based techniques in the last 10 years, our review indicates that Raman spectroscopy (RS) technique has been applied exclusively for the diagnosis of malaria and arboviruses. The mid-infrared spectroscopy (MIRS) technique has been assessed for the diagnosis of malaria parasites in human blood and as a surveillance tool for malaria vectors, whereas the near-infrared spectroscopy (NIRS) technique has almost exclusively been applied as a surveillance tool for malaria and arbovirus vectors.Conclusions/SignificanceThe potential of RS as a surveillance tool for malaria and arbovirus vectors and MIRS for the diagnosis and surveillance of arboviruses is yet to be assessed. NIRS capacity as a surveillance tool for malaria and arbovirus vectors should be validated under field conditions, and its potential as a diagnostic tool for malaria and arboviruses needs to be evaluated. It is recommended that all 3 techniques evaluated simultaneously using multiple machine learning techniques in multiple epidemiological settings to determine the most accurate technique for each application. Prior to their field application, a standardised protocol for spectra collection and data analysis should be developed. This will harmonise their application in multiple field settings allowing easy and faster integration into existing disease control platforms. Ultimately, development of rapid and cost-effective point-of-care diagnostic tools for malaria and arboviruses based on spectroscopy techniques may help combat current and future outbreaks of these infectious diseases.