Uptake of glycolic acid by a marine bivalve

Glycolic acid is accumulated by in vitro preparations of gill tissue from the quahog clam, Mercenaria sp., by a process indicating diffusion kinetics. Carbon-14 from labelled glycolic acid was found in the lipid fraction of the gill tissue. Evolution of labelled carbon dioxide suggests that the glycolic acid is metabolized in gill tissue.     

Behavioral parameters of six populations of Meccus phyllosomus longipennis (Heteroptera: Reduviidae) from areas with high and low prevalences of Trypanosoma cruzi human infection

Three behaviors of epidemiological importance, namely feeding latency, feeding duration and defecation latency, for six populations of Meccus phyllosomus longipennis (Usinger) from areas of central, western and north-central Mexico with high (HP) and low (LP) prevalence of Trypanosoma cruzi (Chagas) human infection were evaluated in this study. The median feeding latency (the time taken to begin feeding) was highly variable between instars. Within–instar comparisons showed that at least 65% of the LP populations (N3 to adult) started to feed significantly (P < 0.05) later than the HP population, with N1 showing no difference, and N2 from LP populations feeding sooner than those from HP populations. The six populations had similar median feeding durations within instars. A higher (P < 0.05) percentage of the instars from HP populations defecated faster than the respective instars from the three LP populations. Approximately 25% of the young nymphs (N1 to N3) and females in the HP populations defecated < 2 min postfeeding, compared with 4%–6% of the young nymphs and 1.3%–3% of females in the LP populations. Moreover, 17.7%–38.8% of the older nymphs (N4 to N5) in the HP populations and 6.8%–13.4% in the LP populations defecated during or immediately after feeding. Our results indicate that the HP populations have a greater potential than the LP populations to transmit T. cruzi infections, which may underlie the differences in the prevalence of T. cruzi infection in some areas where M. p. longipennis is currently distributed.     

Spatial distribution of lead in the roots of human primary teeth

Lead remains one of the most hazardous metals in our environment. The concentrations of lead in coronal dentine and enamel have previously been reported but limited information is available regarding lead levels in radicular dentine and cementum. This study reports the distribution of lead in 26 roots of 16 human maxillary primary teeth from seven individuals. In addition, calcium and phosphorous concentrations were also measured to detect any variations in the degree of mineralization in different regions of the roots. The mean lead concentration in these roots was 1.67 +/- 1.43 microg/g, which is comparable to other studies. In all cases there were higher lead concentrations in the apices of non-resorbed roots of primary maxillary teeth relative to middle and cervical regions. The findings reported here are of potential significance during the process of physiological root resorption whence periapical tissue may be exposed to higher levels of lead.     

Evidence of free fatty acid interdigitation in stratum corneum model membranes based on ceramide [AP] by deuterium labelling

This research paper provides direct evidence concerning the localisation of free fatty acids in stratum corneum lipid model membranes. We employed partially deuterated free fatty acids to gain further information about the assembly of a stratum corneum lipid model membrane based on a ceramide of the phytosphingosine-type (ceramide [AP]) with particular respect to the position of the deuterated groups of the free fatty acids. The application of behenic-22,22,22-d₃-acid and cerotic-12,12,13,13-d₄-acid confirmed that the short-chain ceramide [AP] forces the longer-chained free fatty acids to incorporate into the bilayer created by ceramide [AP]. The ceramide [AP] molecules determine the structural assembly of this model membrane and obligate the long-chain free fatty acids to either arrange inside this formation or to separate as a fatty acid rich phase.     

Acoustic monitoring reveals diversity and surprising dynamics in tropical freshwater soundscapes

1. Freshwater systems are globally threatened and in need of enhanced monitoring and assessment. We applied soundscape recording and analysis—which presents an opportunity for long-term, high-resolution animal community monitoring and assessment—to a freshwater context to better understand the acoustic diversity and dynamics of these systems.
2. We recorded the aquatic soundscape of a Neotropical freshwater swamp in Costa Rica for 23 days in January and February 2015 during the dry season. We classified biological sound types in these recordings and developed measurements of richness and occupancy based on this classification. We also calculated six complementary acoustic indices to assess soundscape diversity and daily and longer-term soundscape dynamics, and we examined correlations between these acoustic indices and sound type metrics.
3. We found rich soundscapes in which biological sounds were almost always present, and we classified 18 sound types that we attribute to aquatic insects. These sound types showed distinct daily patterns and exhibited temporal and spectral acoustic niche partitioning. Sound type richness was most correlated with the number of peaks index (correlation = .36; p < .001), while sound type occupancy was most correlated with the Bioacoustic Index (correlation = .92; p < .001). In contrast to generally high levels of acoustic activity, there were brief (approximately 1 hr), unexpected quiet periods around dawn and dusk.
4. This study represents an early attempt to comprehensively describe tropical freshwater soundscapes in a systematic and quantitative manner. We demonstrate that sound type classification and the quantification of acoustic occupancy capture aspects of soundscape diversity and dynamics that are complementary to those assessed by acoustic indices. Our analyses reveal that the soundscapes of this tropical wetland were diverse and exhibited daily dynamics that differed from those found in other ecosystems.

     

Grading of the prostate carcinoma: cyto-histological correlations on 100 cases

From January 1980 to December 1983, 154 patients underwent prostatic FNAB and histological control. The sensitivity of cytology was 85%, the specificity 68% and the predictive value of positive cases 83%. The cyto-histological correlation of the grading of the 100 prostatic carcinomas histologically confirmed (85 cytologically positive for carcinoma and 15 negative or uncertain) showed a predictive value of positive results of 58%, ranging from 42% for G3, 50% for G1 and 69% for G2. The usefulness of cytological grading is stressed to monitor the follow-up of those patients treated for prostatic carcinoma who, because of the advanced stage or age, were not surgically treated.     

Extraterrestrial Flux of Potentially Prebiotic C, N, and P to the Early Earth

With growing evidence for a heavy bombardment period ending 4–3.8 billion years ago, meteorites and comets may have been an important source of prebiotic carbon, nitrogen, and phosphorus on the early Earth. Life may have originated shortly after the late-heavy bombardment, when concentrations of organic compounds and reactive phosphorus were enough to “kick life into gear”. This work quantifies the sources of potentially prebiotic, extraterrestrial C, N, and P and correlates these fluxes with a comparison to total Ir fluxes, and estimates the effect of atmosphere on the survival of material. We find (1) that carbonaceous chondrites were not a good source of organic compounds, but interplanetary dust particles provided a constant, steady flux of organic compounds to the surface of the Earth, (2) extraterrestrial metallic material was much more abundant on the early Earth, and delivered reactive P in the form of phosphide minerals to the Earth’s surface, and (3) large impacts provided substantial local enrichments of potentially prebiotic reagents. These results help elucidate the potential role of extraterrestrial matter in the origin of life.     

Pityriasis versicolor: Unicity or duality?

Comment on P. Imwidthaya, M. Thianprasit and S. Srimuang: A study ofPityriasis versicolor in Bangkok, Thailand (Mycopathologia 1989; 105: 157–161).