Experimental and theoretical study on high temperature induced changes in chlorophyll <Emphasis Type="Italic">a</Emphasis> fluorescence oscillations in barley leaves upon 2 % CO<Subscript>2</Subscript>

Oscillations in many of photosynthetic quantities with a period of about 1 min can be routinely measured with higher plant leaves after perturbation of the steady state by sudden change in gas phase. Among all hypotheses suggested so far to explain the oscillations, an effect of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activation status to control the oscillations is highly probable, at least upon high temperature (HT) treatment when in vivo RuBPCO activity controlled by RuBPCO activase (RuBPCO-A) decreases. Therefore, we measured the oscillations in fluorescence signal coming from barley leaves (Hordeum vulgare L. cv. Akcent) after their exposure for various time intervals to different HTs in darkness. We also evaluated steady state fluorescence and CO₂ exchange parameters to have an insight to functions of electron transport chain within thylakoid membrane and Calvin cycle before initiation of the oscillations. The changes in period of the oscillations induced by moderate HT (up to 43 °C) best correlated with changes in non-photochemical fluorescence quenching (q_N) that in turn correlated with changes in gross photosynthetic rate (P _G) and rate of RuBPCO activation (k_act). Therefore, we suggest that changes in period of the oscillations caused by moderate HT are mainly controlled by RuBPCO activation status. For more severe HT (45 °C), the oscillations disappeared which was probably caused by an insufficient formation of NADPH by electron transport chain within thylakoid membrane as judged from a decrease in photochemical fluorescence quenching (q_P). Suggestions made on the basis of experimental data were verified by theoretical simulations of the oscillations based on a model of Calvin cycle and by means of a control analysis of the model.     

On the morphology of trichophyton quinckeanum

Summary The cultivation of four old non-sporulating strains ofTrichophyton quinckeanum on solid nutrient medium with 15% CO₂ (Sabouraud dextrose agar) gave an increased production of macroconidia. The macroconidia are multilocular with smooth walls. It is believed that the polymorphism of the macroconidia — some with pointed tip and other with round terminal cell — is characteristic of the species and has a taxonomic significance. Macroconidia with a pointed end cell are not of theMicrosporon type, since they have smooth walls and are not pointed on both ends Filiform appendages from the terminal cell occur regularly. Small and large macroconidia were seen. The microconidia are pyriform or elongated. No rounded microconidia withBotrytis type of arrangement were observed. The so-calledT. niveum is probably identical withT. quinckeannum.Together with the characteristics of the species as a parasite it is to be concluded thatT. quinckeanum is a peculiar dermatophyte species, corresponding toQuincke's -Pilz, but cannot be assimilated by the group ofT. mentagrophytes (Ctenomyces s. microides).     

Immunity status against coxsackie viruses B in 25 patients with acute myocarditis

Viruses are an important cause of myocarditis, particularly the enterovirus group B coxsackievirus. Viral infection may be suspected on the basis of history and presentation and can be proved by direct or serological identification of virus. Twenty-five patients were diagnosed with acute myocarditis and were investigated with a serologic test battery covering Coxsackie viruses group B types 1 to 5 at the National Reference Center for Enteroviruses in Cantacuzino Institute Bucharest, Romania. A possible Coxsakie B virus etiology could be documented in 11 from 25 cases with acute myocarditis and high titers against Coxsackie virus B type 2 (1 patient), type 3 (5 patients) and type 5 (in 4 patients) were detected. In one HIV positive patient (17 years old), a concomitant infection with Coxsackie virus B types 2 and 4 was detected. The earlier detection of enterovirus myocarditis could be followed by antiviral therapies with a potential therapeutic role.     

Interactions among flavonoids of propolis affect antibacterial activity against the honeybee pathogen Paenibacillus larvae

Propolis is derived from plant resins, collected by honeybees (Apis mellifera) and renown for its antibacterial properties. Here we test the antibacterial effects of ethanolic extracts of propolis from different origins on Paenibacillus larvae, the bacterial pathogen that causes American Foulbrood, a larval disease that can kill the honeybee colony. All tested propolis samples inhibited significantly the growth of P. larvae tested in vitro. The extracts showed major differences in the content of total flavonoids (ranging from 2.4% to 16.4%) and the total polyphenols (ranging between 23.3% and 63.2%). We found that it is not only the content of compounds in propolis, which influences the strength of antimicrobial effects but there is also a significant interaction effect among flavonoids of the propolis extracts. We propose that interaction effects among the various chemical compounds in propolis should be taken into account when considering the antibacterial effects against honeybee pathogens.     

Imaging proteins inside cells with fluorescent tags

Watching biological molecules provides clues to their function and regulation. Some of the most powerful methods of labeling proteins for imaging use genetically encoded fluorescent fusion tags. There are four standard genetic methods of covalently tagging a protein with a fluorescent probe for cellular imaging. These use (i) autofluorescent proteins, (ii) self-labeling enzymes, (iii) enzymes that catalyze the attachment of a probe to a target sequence, and (iv) biarsenical dyes that target tetracysteine motifs. Each of these techniques has advantages and disadvantages. In this review, we cover new developments in these methods and discuss practical considerations for their use in imaging proteins inside living cells.     

Rethinking fakes,authenticating selves

People who engage with objects that are deemed inauthentic under intellectual property laws might dismiss this classification and might ascribe different meanings to these objects. However, they cannot always disregard it, as circumstances might at any time bring this classification to the fore. In such situations, they are not only accused of deceiving others, but also derided for the deception they presumably work upon themselves. Drawing upon an ethnography of people's engagement with fake branded garments in Turkey and Romania and using theoretical perspectives on materiality and authenticity, I argue that a reconceptualization of the fake is a dignifying resolution to this crisis of authenticity. The fake is seen as a copy that does not hide its true nature. This is further elaborated on, in light of individual agendas and approaches to the world. These objects are ‘similar enough’, ‘good enough’, and ‘famous enough’. The fake is, thus, ‘sort of something’, the approximation of the ideal. Moreover, the fake is truthful to how the world truly is, namely a place full of half‐truths and half‐measures. The fake is, therefore, ‘sort of something’, as opposed to being ‘absolutely something’, the objectification of the ideal.     

Amphibian Pathogens in Southeast Asian Frog Trade

Amphibian trade is known to facilitate the geographic spread of pathogens. Here we assess the health of amphibians traded in Southeast Asia for food or as pets, focusing on Batrachochytrium dendrobatidis (Bd), ranavirus and general clinical condition. Samples were collected from 2,389 individual animals at 51 sites in Lao PDR, Cambodia, Vietnam and Singapore for Bd screening, and 74 animals in Cambodia and Vietnam for ranavirus screening. Bd was found in one frog (n = 347) in Cambodia and 13 in Singapore (n = 419). No Bd was found in Lao PDR (n = 1,126) or Vietnam (n = 497), and no ranavirus was found in Cambodia (n = 70) or Vietnam (n = 4). Mild to severe dermatological lesions were observed in all East Asian bullfrogs Hoplobatrachus rugolosus (n = 497) sampled in farms in Vietnam. Histologic lesions consistent with sepsis were found within the lesions of three frogs and bacterial sepsis in two (n = 4); one had Gram-negative bacilli and one had acid-fast organisms consistent with mycobacterium sp. These results confirm that Bd is currently rare in amphibian trade in Southeast Asia. The presence of Mycobacterium-associated disease in farmed H. rugolosus is a cause for concern, as it may have public health implications and indicates the need for improved biosecurity in amphibian farming and trade.