Physiological responses of Sargasso Sea picoplankton to nanomolar nitrate perturbations

A study was conducted in July 1989 at three stations in thenorthern Sargasso Sea, where picoplankton (<1 µm)provided approximately half of the standing crop of chlorophyll.Temporal changes in the position of the nitracline at a singlelocation indicated that the vertical supply of nitrate was notat ‘steady-state’ and phytoplankton distributionstracked the nitracline. Our main experimental objective wasto examine the short-term effects of ecologically significantnitrate perturbations (+20 and +100 nM) on the physiologyof <1 µm communities growing at low (nanomolar)ambient nitrate concentrations. A chemiluminescent nitrate methodwas used to measure the time course (up to 4 h) of nitratedisappearance at in situ irradiance, in parallel with measurementsof photosynthetic ¹⁴CO₂ assimilation. Picoplankton growing at<60 nM nitrate rapidly responded to nanomolar nitratesupplements with luxury consumption and enhanced photosynthesisin proportion to their ambient nitrate environment. Light-saturatedSynechococcus populations from the most nitrate-depleted waters(13 nM) had doubled their cellular rate of photosynthesisafter 4 h, in response to a 20 nM nitrate pulse.     

Onchocerciasis in British cattle: a study of Onchocerca gutturosa and O. lienalis in North Wales

Onchocerca gutturosa and O. lienalis infections in British cattle were studied by examination of cattle post-mortem originating from North Wales and Cheshire (north west England). In 463 adult animals, the microfilarial (mf) prevalence was 28.5%. In 95.3% of the mf infected animals, gravid worms could not be found at either the ligamentum nuchae or the gastro-splenic omentum. Dermal mf at the head were identified as O. gutturosa on the basis of their highly significant association with the presence of gravid O. gutturosa at the ligamentum nuchae, which were found in only 3.2% of cattle. Mfs were isolated from different skin sites and from adult worms and a minimum of 10 mfs from each isolate were examined for width and acid phosphatase (AP) staining pattern. The width of O. gutturosa dermal mf was less than 4 micron (4 isolations), narrower than that of putative O. lienalis mf isolated from umbilical skin of cattle without evidence of O. gutturosa, which were in 20/22 isolations greater than 4 micron wide. The dermal mf were also distinguished on the basis of different AP staining patterns which, for each species, correlated closely with that of hatched intrauterine mf from their respective adult female worms. Based on the criteria of morphology and AP staining patterns the mf species prevalences in the survey population were estimated as O. lienalis 24.1% and O. gutturosa 2.2%, with a further 2.2% of cattle infected with both species. The results indicate that the predilection site of adult O. lienalis is not the gastro-splenic omentum. In North Wales, the distribution of the two species was different; O. lienalis was widely distributed in all cattle rearing areas both lowland and upland, whereas O. gutturosa was largely restricted to valleys close to major rivers.     

Female wing spreading as acceptance signal in theDrosophila virilis group of species

Females of manyDrosophila species spread apart their wings prior to copulation. In the present study we found female wing spreading to provoke male copulation attempts inDrosophila virilis-group species, helping the males to attempt copulation when the female is ready to mate. The males of most species, however, rarely responded to female wing spreading by copulation attempt without licking the female genitalia before and/or after female wing spreading bout. Blocking the female genitalia (D. virilis, D. novamexicana) reduces males' tendency to attempt copulation after female wing spreading. In these, and most other species of the group, female wing spreading seems to be an efficient signal only when combined with stimuli from female genitalia.     

Inter-twin relationships and mental health.

We evaluated dominance-submissiveness between co-twins and its relationship to mental health in a cohort study of 419 twins followed from pregnancy to 22-30 years of age. Dominance-submissiveness between co-twins was assessed from three separate perspectives: physical dominance, psychological dominance, and verbal dominance. Depressive, nervous, and psychosomatic symptoms were analyzed in different twin groups. In the physical domain, males were more commonly dominant than females at school age and in adulthood. Before and at school age, girls were more dominant than boys in the psychological and verbal domains, as well as in total dominance. These differences disappeared in adulthood, and 81% of adult twins felt themselves equal to their co-twin in total dominance. Submissiveness in the psychological domain seemed to be associated with increased depressiveness, nervous complaints and psychosomatic symptoms in males of male-female twin pairs. Verbally submissive males in same-sex twin pairs had more depression and psychosomatic symptoms. Among females of same-sex twin pairs, submissiveness in the psychological domain was most clearly associated with depressive symptoms, whereas psychological or verbal dominance-submissiveness among females from male-female twin pairs was not associated with symptoms. Psychologically dominant males and females of same-sex twin pairs expressed greater nervousness than did their co-twins. We conclude that being submissive, especially in the psychological domain, to a female twin partner seems to be stressful, whereas it is easier, especially for females, to be submissive to a male twin partner.     

Outbreak of Shiga Toxin-Producing Escherichia coli (STEC) O157:H7 Associated with Romaine Lettuce Consumption, 2011

Background

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is the causal agent for more than 96,000 cases of diarrheal illness and 3,200 infection-attributable hospitalizations annually in the United States.

Materials and Methods

We defined a confirmed case as a compatible illness in a person with the outbreak strain during 10/07/2011-11/30/2011. Investigation included hypothesis generation, a case-control study utilizing geographically-matched controls, and a case series investigation. Environmental inspections and tracebacks were conducted.

Results

We identified 58 cases in 10 states; 67% were hospitalized and 6.4% developed hemolytic uremic syndrome. Any romaine consumption was significantly associated with illness (matched Odds Ratio (mOR) = 10.0, 95% Confidence Interval (CI) = 2.1–97.0). Grocery Store Chain A salad bar was significantly associated with illness (mOR = 18.9, 95% CI = 4.5–176.8). Two separate traceback investigations for romaine lettuce converged on Farm A. Case series results indicate that cases (64.9%) were more likely than the FoodNet population (47%) to eat romaine lettuce (p-value = 0.013); 61.3% of cases reported consuming romaine lettuce from the Grocery Store Chain A salad bar.

Conclusions

This multistate outbreak of STEC O157:H7 infections was associated with consumption of romaine lettuce. Traceback analysis determined that a single common lot of romaine lettuce harvested from Farm A was used to supply Grocery Store Chain A and a university campus linked to a case with the outbreak strain. An investigation at Farm A did not identify the source of contamination. Improved ability to trace produce from the growing fields to the point of consumption will allow more timely prevention and control measures to be implemented.     

A Novel Dictionary Based Computer Vision Method for the Detection of Cell Nuclei

Cell nuclei detection in fluorescent microscopic images is an important and time consuming task in a wide range of biological applications. Blur, clutter, bleed through and partial occlusion of nuclei make individual nuclei detection a challenging task for automated image analysis. This paper proposes a novel and robust detection method based on the active contour framework. Improvement over conventional approaches is achieved by exploiting prior knowledge of the nucleus shape in order to better detect individual nuclei. This prior knowledge is defined using a dictionary based approach which can be formulated as the optimization of a convex energy function. The proposed method shows accurate detection results for dense clusters of nuclei, for example, an F-measure (a measure for detection accuracy) of 0.96 for the detection of cell nuclei in peripheral blood mononuclear cells, compared to an F-measure of 0.90 achieved by state-of-the-art nuclei detection methods.     

The NAD-Booster Nicotinamide Riboside Potently Stimulates Hematopoiesis through Increased Mitochondrial Clearance

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Genotyping of Toxoplasma gondii associated with abortion in sheep

Genotypes of Toxoplasma gondii in naturally infected tissues from 13 ovine abortions from 10 farms in the United Kingdom, from 2 wild rodents captured on 1 farm, and from 2 isolates in laboratory mouse brains (made from the hearts of healthy, infected lambs) all conformed to the type II lineage determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the SAG2 gene. PCR was applied directly to tissue extracts without parasite isolation or DNA extraction. These results demonstrate the feasibility of direct analysis of T. gondii lineages from samples derived either from clinical cases or asymptomatic infections.     

The dibenzodioxocin lignin substructure is abundant in the inner part of the secondary wall in Norway spruce and silver birch xylem

A specific condensed lignin substructure, dibenzodioxocin, was immunolocalized in differentiating cell walls of Norway spruce (Picea abies (L.) H. Karsten) and silver birch (Betula pendula Roth) xylem. A fluorescent probe, Alexa 488 was used as a marker on the dibenzodioxocin-specific secondary antibody. For the detection of this lignin substructure, 25-m cross-sections of xylem were viewed with a confocal laser-scanning microscope with fluorescein isothiocyanate fluorescence filters. In mature cells, fluorescence was detected in the S3 layer of the secondary wall in both tree species, but it was more intense in Norway spruce than in silver birch. In silver birch most of the signal was detected in vessel walls and less in fiber cell walls. In very young tracheids of Norway spruce and vessels and fibers of silver birch, where secondary cell wall layers were not yet formed, the presence of the dibenzodioxocin structure could not be shown.Abbreviation CLSM confocal laser-scanning fluorescence microscopy     

Ultrasonography in early pregnancy diagnosis and measurements of fetal size in reindeer (Rangifer tarandus tarandus)

Transrectal or transabdominal examinations of 13 pluriparous reindeer (Rangifer tarandus tarandus) by ultrasonography from the start of mating until week 20 of gestation were conducted to find out when pregnancy could first be detected and to describe fetal development in early pregnancy. The examinations (n=35 per animal) were performed with a 5 MHz linear transducer from 7th October until 1st January and with a 3 MHz sector transducer from that time until 24th February. Time of pregnancy diagnosis by ultrasonography, the first fetal heartbeat and measurements of crown-rump length, chest width and chest depth were recorded during the examinations. Pregnancy was diagnosed by transrectal ultrasonography between the weeks 3 and 7 of gestation. The accuracy of the pregnancy diagnosis, defined as the proportion of females correctly detected to be pregnant, was 15% at week 3, 46% at week 4, 77% at week 5, and 92% at week 6 of gestation. Fetal heartbeat was first detected between the weeks 5 and 8 of gestation. The first measurements of crown-rump length were made on week 3 of gestation, of chest width on week 4 and of chest depth on week 5 of gestation. Chest width and depth were detectable until the end of the study at week 20 of gestation. Transrectal ultrasonography is an efficient tool in early pregnancy diagnosis of reindeer. The fetal growth curves obtained by ultrasonography resembled those obtained in previous morphological studies.