A new protein factor functional in the ferredoxin-independent light activation of chloroplast fructose 1,6-bisphosphatase

A protein purified from chloroplasts (the “new protein factor”) activated Fru-P₂ase in a photochemical reaction that depended only on chloroplast membranes. The results suggest that chloroplasts utilize the newly found mechanism for the photoregulation of Fru-P₂ase in addition to the recently described ferredoxin/thioredoxin system.     

Release of norepinephrine from the rat ovary: local modulation of gonadotropins.

Experiments were undertaken to define the role of gonadotropins in the release of norepinephrine and the relationship with beta-receptors of the ovary. Rat ovaries were removed at different stages of the estrous cycle and incubated in [3H]norepinephrine. Subsequently, ovaries were electrically stimulated and the release of [3H]norepinephrine was recorded. There were no changes in the norepinephrine content during the estrous cycle. The ovary exhibited cyclical variation in norepinephrine-induced release during the estrous cycle. The lowest release of norepinephrine was found during diestrus; there was an increase during proestrus and estrus followed by a decline during metestrus. The release of norepinephrine changed in the opposite way to the beta-receptor number, suggesting a process involving down-regulation between norepinephrine release and beta-receptors of the ovary. Norepinephrine released from the ovary was locally regulated by gonadotropins. The presence of FSH in the superfusion medium stimulated the norepinephrine-induced release from the ovaries of rats in diestrus (by 20%) and estrus (by 40%), but no effect was found during proestrus. In addition, the presence of hCG stimulated (by 40%) norepinephrine-induced release during proestrus, but no changes were apparent during the other stages of the estrous cycle. These results suggest that the local action of gonadotropins on nerve terminals of the ovary might be one of the factors governing the changes in norepinephrine release through the estrous cycle. The changes in the norepinephrine released to the synaptic cleft might exert down-regulation on the beta-adrenergic receptor content of the ovary and in this way control the ovarian steroid secretory activity.     

Helicobacter pylori disrupts NADPH oxidase targeting in human neutrophils to induce extracellular superoxide release

Helicobacter pylori (Hp) infection triggers a chronic influx of polymorphonuclear leukocyte neutrophils (PMNs) into the gastric mucosa. Although Hp reside in a neutrophil-rich environment, how these organisms evade phagocytic killing is largely unexplored. We now show that live Hp (strains 11637, 60190, DT61A, and 11916) are readily ingested by PMNs and induce a rapid and strong respiratory burst that is comparable to PMA. Relative to other particulate stimuli, Hp are more potent activators of PMNs than opsonized zymosan, Staphylococcus aureus, or Salmonella. Strikingly, biochemical and microscopic analyses demonstrate that Hp disrupt NADPH oxidase targeting such that superoxide anions are released into the extracellular milieu and do not accumulate inside Hp phagosomes. Specifically, nascent Hp phagosomes acquire flavocytochrome b558 but do not efficiently recruit or retain p47phox or p67phox. Superoxide release peaks at 16 min coincident with the appearance of assembled oxidase complexes in patches at the cell surface. Oxidant release is regulated by formalin-resistant and heat-sensitive bacterial surface factors distinct from urease and Hp(2-20). Following opsonization with fresh serum, Hp triggers a modest respiratory burst that is confined to the phagosome, and ingested bacteria are eliminated. We conclude that disruption of NADPH oxidase targeting allows unopsonized Hp to escape phagocytic killing, and our findings support the hypothesis that bacteria and PMNs act in concert to damage the gastric mucosa.     

Diagnostics for herpes simplex virus: is PCR the new gold standard?

Herpes simplex virus (HSV) is one of the most common, yet frequently overlooked, sexually transmitted infections. Since the type of HSV infection affects prognosis and subsequent counseling, type-specific testing to distinguish HSV-1 from HSV-2 is recommended. Although PCR has been the diagnostic standard for HSV infections of the central nervous system, until now viral culture has been the test of choice for HSV genital infection. However, HSV PCR, with its consistently and substantially higher rate of HSV detection, will likely replace viral culture as the gold standard for the diagnosis of genital herpes in people with active mucocutaneous lesions, regardless of anatomic location or viral type. Alternatively, type-specific serologic tests based on glycoprotein G should be the test of choice to establish the diagnosis of HSV infection when no active lesion is present. Given the difficulty in making the clinical diagnosis of HSV, the growing worldwide prevalence of genital herpes and the availability of effective antiviral therapy, there is an increased demand for rapid, accurate laboratory diagnosis of patients with HSV.     

Studying the Effects of Reproductive Hormones and Bacterial Vaginosis on the Glycome of Lavage Samples from the Cervicovaginal Cavity

The cervicovaginal fluid (CVF) coating the vaginal epithelium is an important immunological mediator, providing a barrier to infection. Glycosylation of CVF proteins, such as mucins, IgG and S-IgA, plays a critical role in their immunological functions. Although multiple factors, such as hormones and microflora, may influence glycosylation of the CVF, few studies have examined their impact on this important immunological fluid. Herein we analyzed the glycosylation of cervicovaginal lavage (CVL) samples collected from 165 women under different hormonal conditions including: (1) no contraceptive, post-menopausal, (2) no contraceptive, days 1-14 of the menstrual cycle, (3) no contraceptive, days 15-28 of the menstrual cycle, (4) combined-oral contraceptive pills for at least 6 months, (5) depo-medroxyprogesterone acetate (Depo-Provera) injections for at least 6 months, (6) levonorgestrel IUD for at least 1 month. Glycomic profiling was obtained using our lectin microarray system, a rapid method to analyze carbohydrate composition. Although some small effects were observed due to hormone levels, the major influence on the glycome was the presence of an altered bacterial cohort due to bacterial vaginosis (BV). Compared to normal women, samples from women with BV contained lower levels of sialic acid and high-mannose glycans in their CVL. The change in high mannose levels was unexpected and may be related to the increased risk of HIV-infection observed in women with BV, as high mannose receptors are a viral entry pathway. Changes in the glycome were also observed with hormonal contraceptive use, in a contraceptive-dependent manner. Overall, microflora had a greater impact on the glycome than hormonal levels, and both of these effects should be more closely examined in future studies given the importance of glycans in the innate immune system.     

Survey of Sand Flies (Diptera: Psychodidae) in an Environmentally Protected Area in Brazil

Brazil is one of the most important endemic areas for leishmaniasis worldwide. Protected areas that are tourist attractions likely present an important risk of transmission of cutaneous leishmaniasis (CL). Furthermore, with the geographical expansion of visceral leishmaniasis (VL), several studies have recorded the occurrence of its vector, Lutzomyia longipalpis, and cases of human and canine VL in such tourist areas. The Parque Estadual do Sumidouro is an environmentally protected area located in the Brazilian Cerrado biome and in an important area endemic for leishmaniasis in the state of Minas Gerais. The purpose of this study was to monitor the sand fly fauna in areas of tourist activity in the park. Sampling was performed every month, from September 2011 to August 2013, using CDC light traps at six sites of differing environmental characteristics. Sampled specimens were identified following Galati (2003), and females were submitted to molecular techniques for the detection and identification of Leishmania DNA. A total of 4,675 sand fly specimens of 25 species belonging to nine genera were collected. The most abundant species were Micropygomyia quinquefer, Lutzomyia renei and Pintomyia pessoai, although only Pi. pessoai is implicated in the transmission of Leishmania braziliensis. The species accumulation curve reached saturation on the 16th sampling event. Species richness, diversity and evenness differed among the sampled areas. The seasonal curve was not determined by a single unique species, and no single species was the most abundant in all environments sampled. The main vector of Leishmania (Leishmania) infantum, Lutzomyia longipalpis, accounted for only 5.35% of the specimens collected. Proven or suspected vectors of Leishmania (Viannia) braziliensis were recorded, and one female of the cortellezzii complex tested positive for Le. braziliensis DNA. Even with a low infection rate (0.62%), these data indicate the circulation of the parasite and reinforce the need for entomological and epidemiological surveillance in the park and its surroundings.     

Patterns and drivers of Araucaria araucana forest growth along a biophysical gradient in the northern Patagonian Andes: Linking tree rings with satellite observations of soil moisture

Araucaria araucana (Araucaria) is a long‐lived conifer growing along a sharp west–east biophysical gradient in the Patagonian Andes. The patterns and climate drivers of Araucaria growth have typically been documented on the driest part of the gradient relying on correlations with meteorological records, but the lack of in situ soil moisture observations has precluded an assessment of the growth responses to soil moisture variability. Here, we use a network of 21 tree‐ring width chronologies to investigate the spatiotemporal patterns of tree growth through the entire gradient and evaluate their linkages with regional climate and satellite‐observed surface soil moisture variability. We found that temporal variations in tree growth are remarkably similar throughout the gradient and largely driven by soil moisture variability. The regional spatiotemporal pattern of tree growth was positively correlated with precipitation (r = 0.35 for January 1920–1974; P < 0.01) and predominantly negatively correlated with temperature (r = ?0.38 for January–March 1920–1974; P < 0.01) during the previous growing season. These correlations suggest a temporally lagged growth response to summer moisture that could be associated with known physiological carry‐over processes in conifers and to a response to moisture variability at deeper layers of the rooting zone. Notably, satellite observations revealed a previously unobserved response of Araucaria growth to summer surface soil moisture during the current rather than the previous growing season (r = 0.65 for 1979–2000; P < 0.05). This new response has a large spatial footprint across the mid‐latitudes of the South American continent (35°–45°S) and highlights the potential of Araucaria tree rings for palaeoclimatic applications. The strong moisture constraint on tree growth revealed by satellite observations suggests that projected summer drying during the coming decades may result in regional growth declines in Araucaria forests and other water‐limited ecosystems in the Patagonian Andes.