Effect of Lincocin Treatment on the Greening Process in Bean (Phaseolus vulgaris) Leaves

The effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied. In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –¹⁴CO₂ fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum-like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed. The results indicate some structural and functional membrane deficiencies and instability of the membranes.     

Female control of sperm ejection and retention in the cornsilk fly Euxesta eluta (Diptera: Ulidiidae)

Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males. However, distinguishing between male sperm competition and active female sperm choice is difficult for species with internal fertilization. Nevertheless, species that store and use sperm of different males in different storing structures and species where females are able to expel all or part of the ejaculates after copulation may be able to bias fertilization. We report a series of experiments aimed at providing evidence of female sperm choice in Euxesta eluta (Hendel), a species of ulidiid fly that expels and consumes ejaculates after copulation. We found no evidence of greater reproductive success for females mated singly, multiply with the same male, or mated multiply with different males. Female E. eluta possesses two spherical spermathecae and a bursa copulatrix for sperm storage, with a ventral receptacle. There was no significant difference in storing more sperm in spermathecae 24 h after copulation than immediately after copulation. Females mated with protein-fed males had greater reproductive success than similar females mated to protein-deprived males. Protein-fed females prevented to consume the ejaculate, retained more sperm when mated to protein-fed males than when mated to protein-deprived males. Our results suggest that female E. eluta can exert control of sperm retention of higher quality males through ejaculate ejection.     

Terpen-derivate aus Senecio-arten

Investigation of about 50 Senecio species has afforded many new substances, in addition to known compounds. Present in these plants are 23 fura     

High Prevalence of Cryptococcal Antigenemia among HIV-infected Patients Receiving Antiretroviral Therapy in Ethiopia

Background

Cryptococcal disease is estimated to be responsible for significant mortality in Sub-Saharan Africa; however, only scarce epidemiology data exists. We sought to evaluate the prevalence of and risk factors for cryptococcal antigenemia in Ethiopia.

Methods

Consecutive adult HIV-infected patients from two public HIV clinics in Addis Ababa, Ethiopia were enrolled into the study. A CD4 count ≤200 cells/μl was required for study participation. Patients receiving anti-retroviral therapy (ART) were not excluded. A cryptococcal antigen test was performed for all patients along with an interview, physical exam, and medical chart abstraction. Logistic regression analysis was used to assess risk factors for cryptococcal antigenemia.

Results

369 HIV-infected patients were enrolled; mean CD4 123 cells/μl and 74% receiving ART. The overall prevalence of cryptococcal antigenemia was 8.4%; 11% in patients with a CD4 count <100 cells/μl, 8.9% with CD4 100 to 150 cells/μl and 5.7% with CD4150-200 cell/μl. 84% of patients with cryptococcal antigenemia were receiving ART. In multivariable analysis, increasing age, self reported fever, CD4 count <100 cells/μl, and site of screening were associated with an increased risk of cryptococcal antigenemia. No individual or combination of clinical symptoms had optimal sensitivity or specificity for cryptococcal antigenemia.

Conclusion

Cryptococcal antigenemia is high in Ethiopia and rapid scale up of screening programs is needed. Screening should be implemented for HIV-infected patients with low CD4 counts regardless of symptoms or receipt of ART. Further study into the effect of location and environment on cryptococcal disease is warranted.     

In vitro catabolic effect of protoporphyrin IX in human osteoblast-like cells: possible role of the 18 kDa mitochondrial translocator protein

In several pathological conditions, when conversion of Protoporphyrin (PP)IX into heme is impaired, a toxic accumulation of PPIX might occur. PPIX has been found to have affinity to the mitochondrial Translocator Protein 18 kDa. Since it is known that TSPO is abundant in human osteoblast cells, thus we assumed that PPIX can affect cellular functions via interactions with TSPO in these cells. Therefore we aimed to study the metabolic responses of human osteoblast to a high (10^?5M) concentration of PPIX in vitro. We found that in primary culture of human osteoblast-like cells cell numbers decreased following exposure to PPIX(10^?5M). Cellular [¹⁸F]-FDG incorporation, mitochondrial mass, ATP content were suppressed, and ΔΨm collapsed. Lactate dehydrogenase activity was enhanced in culture media, indicating overall cell death, while no increase in apoptotic levels was observed. Cellular proliferation was not affected. Protein expression of TSPO, VDAC 1, and hexokinase 2 decreased, although the synthesis of mRNA for hexokinase 2 increased. Thus, PPIX(10^?5M) has a cytotoxic effect on human osteoblast-like cell in vitro. Since these cells remain viable following exposure to another TSPO ligand, PK 11195 (10^?5M), as observed previously by us, the mode of action of PPIX on osteoblast-like cells is not identical to that of PK 11195. Accordingly pathological accumulation of PPIX may cause necrosis of osteoblasts leading to bone mass loss. We show that this phenomenon is unrelated to iron overload.     

Arrestin‐dependent but G‐protein coupled receptor kinase‐independent uncoupling of D2‐dopamine receptors

We reconstituted D2 like dopamine receptor (D2R) and the delta opioid receptor (DOR) coupling to G‐protein gated inwardly rectifying potassium channels (K_ir3) and directly compared the effects of co‐expression of G‐protein coupled receptor kinase (GRK) and arrestin on agonist‐dependent desensitization of the receptor response. We found, as described previously, that co‐expression of a GRK and an arrestin synergistically increased the rate of agonist‐dependent desensitization of DOR. In contrast, only arrestin expression was required to produce desensitization of D2R responses. Furthermore, arrestin‐dependent GRK‐independent desensitization of D2R‐K_ir3 coupling could be transferred to DOR by substituting the third cytoplasmic loop of DOR with that of D2R. The arrestin‐dependent GRK‐independent desensitization of D2R desensitization was inhibited by staurosporine treatment, and blocked by alanine substitution of putative protein kinase C phosphorylation sites in the third cytoplasmic loop of D2R. Finally, the D2R construct in which putative protein kinase C phosphorylation sites were mutated did not undergo significant agonist‐dependent desensitization even after GRK co‐expression, suggesting that GRK phosphorylation of D2R does not play an important role in uncoupling of the receptor.

     

Foraging ecology of aphidophagous predators against Aphis punicae Passerini

Foraging behaviour of three aphidophagous predators, viz., Cheilomenes sexmaculata (Fabricius), Scymnus sp. (Coleoptera: Coccinellidae) and Paragus serratus (Fabricius) (Diptera: Syrphidae) on prey Aphis punicae Passerini (Homoptera: Aphididae) was studied in the laboratory at Indian Institute of Horticultural Research, Bangalore (12 degrees 58' N; 77 degrees 35'E) during 2002-03 to understand the predation dynamics. The foraging studies of grubs of C. sexmaculata and Scymnus sp. on A. punicae revealed that the distance travelled to reach the food (aphids) was negatively correlated with the feeding time of prey (r = -0.434 and -0.743, respectively). The time taken for second encounter was positively correlated with feeding time in case of both C. sexmaculata (r = 0.715) and P.serratus (r = 0.641). The time taken for first encounter of prey by Scymnus sp. showed negative correlation with the feeding time (r = -0.9491) and positive correlation with the distance traveled by the predator to reach the food (r = 0.620). The foraging behavioural studies of syrphid, P. serratus on A. punicae showed that the time taken for first encounter of prey was positively correlated with both the feeding time (r = 0.467) and the distance travelled by the syrphid to reach the food (r = 0.485). The time taken for first encounter of prey also showed significant positive correlation with the search time of the prey (r = 0.384).     

海南省粗叶木属新记录植物五种

报道发现于海南省鹦哥岭的粗叶木属(Lasianthus Jack)海南省新记录种5种,并描述了它们的主要辨认特征。其中4种(华南粗叶木Lasianthus austrosinensis H.S.Lo、长梗粗叶木L.filipes Chun ex H.S.Lo、西南粗叶木L.henryi Hutch.、台湾粗叶木L.formosensis Matsum.)在与海南邻近的广东省与广西壮族自治区均有记录,而大叶粗叶木L.rigidus Miq.则在热带亚洲具有明显的间断性分布。