The Appearance and Development of Photosynthetic Activity in Etiolated Barley Leaves and Isolated Etio-chloroplasts

The appearance and development of the oxygen exchanging capacity of greening barley leaves were measured using a manometric technique and an oxygen race electrode. An oxygen evolution could first be detected after one hour of greening. During the first hour of greening a light-dependent oxygen uptake was observed. The oxygen evolving capacity, calculated on a chlorophyll weight basis, showed a fast rise in activity during the first hours of greening. A maximal activity was reached after 5 to 10 hours of greening; the oxygen evolution then declined. Using oxygen electrodes different aspects of the electron transport in etio-chloroplasts prepared from the greening barley leaves were also investigated. The activity in photosystem I and II, as well as the cooperation between the two photosystems, were studied by measuring the oxygen exchange from the etio-chloroplasts in the absence and presence of added oxidants and reductants. An activity in photosystem I could be detected already after 5 minutes of greening. The activity of photosystem I, when calculated on a chlorophyll basis, had the same appearance as the oxygen evolution from the intact plant material. An activity in photosystem II and a cooperation between the two photosystems were first detected after 3 hours of greening. After about 15 hours of greening a cooperation corresponding to that from chloroplasts prepared from normal green leaves was observed.     

Redescription of Grania monochaeta (Michaelsen), a Marine Enchytraeid (Oligochaeta) from South Georgia (SW Atlantic)

Enchytraeus monochaetus Michaelsen is redescribed as Grania monochaeta. It is distinguished from other Grania species by two main characters: its morphology of spermathecae, and its setal distribution, the latter being unique within the genus owing to the presence of dorsal setae in preclitellar segments.     

Detection of Ophthalmic Acid in Serum from Acetaminophen-Induced Acute Liver Failure Patients Is More Frequent in Non-Survivors

Background/Aim

Acetaminophen (APAP) hepatotoxicity is related to the formation of N-acetyl-p-benzoquinone imine (NAPQI), which is detoxified through conjugation with reduced glutathione (GSH). Ophthalmic acid (OA) is an analogue of GSH in which cysteine is replaced with 2-aminobutyrate. Metabolomics studies of mice with APAP-induced acute liver failure (APAP-ALF) identified OA as a marker of oxidative stress and hepatic GSH consumption. The aim of the current study was to determine whether OA is detectable in APAP-ALF human patients either early (day 2) or late (day 4) and whether OA levels were associated with in-hospital survival in the absence of liver transplant.

Methods

Serum samples from 130 APAP-ALF patients (82 survivors, 48 non-survivors) were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and correlated with clinical data from the United States Acute Liver Failure Study Group (US ALFSG) Registry (2004–2011).

Results

Survivors had significantly lower admission bilirubin (4.2 vs. 5.7 mg/dl) and lactate levels (3.3 vs. 6.5 μmol/l, p<0.05 for all). During the first 7 days of the study, survivors were less likely to require mechanical ventilation (55% vs. 88%), vasopressor support (9.8% vs. 67%) or renal replacement therapy (26% vs. 63%, p< 0.001 for all). Non-survivors were more likely to have detectable OA levels early (31% vs. 15%, p = 0.034) and late (27% vs. 11%, p = 0.02). However there were no significant differences in mean OA levels between non-survivors and survivors (early 0.48 vs. 0.36, late 0.43 vs. 0.37, P > 0.5 for all).

Conclusion

OA was detectable more frequently in APAP-ALF non-survivors but mean OA levels were not associated with survival. The routine clinical administration of N-acetyl cysteine could replenish GSH levels and prevent OA production.     

Shifting hierarchies of interleukin-10-producing T cell populations in the central nervous system during acute and persistent viral encephalomyelitis

Interleukin-10 (IL-10) mRNA is rapidly upregulated in the central nervous system (CNS) following infection with neurotropic coronavirus and remains elevated during persistent infection. Infection of transgenic IL-10/green fluorescent protein (GFP) reporter mice revealed that CNS-infiltrating T cells were the major source of IL-10, with minimal IL-10 production by macrophages and resident microglia. The proportions of IL-10-producing cells were initially similar in CD8(+) and CD4(+) T cells but diminished rapidly in CD8(+) T cells as the virus was controlled. Overall, the majority of IL-10-producing CD8(+) T cells were specific for the immunodominant major histocompatibility complex (MHC) class I epitope. Unlike CD8(+) T cells, a large proportion of CD4(+) T cells within the CNS retained IL-10 production throughout persistence. Furthermore, elevated frequencies of IL-10-producing CD4(+) T cells in the spinal cord supported preferential maintenance of IL-10 production at the site of viral persistence and tissue damage. IL-10 was produced primarily by the CD25(+) CD4(+) T cell subset during acute infection but prevailed in CD25(-) CD4(+) T cells during the transition to persistent infection and thereafter. Overall, these data demonstrate significant fluidity in the T-cell-mediated IL-10 response during viral encephalitis and persistence. While IL-10 production by CD8(+) T cells was limited primarily to the time of acute effector function, CD4(+) T cells continued to produce IL-10 throughout infection. Moreover, a shift from predominant IL-10 production by CD25(+) CD4(+) T cells to CD25(-) CD4(+) T cells suggests that a transition to nonclassical regulatory T cells precedes and is retained during CNS viral persistence.     

Microglia and the control of autoreactive T cell responses

Microglial activation is one of the earliest and most prominent features of nearly all CNS neuropathologies often occurring prior to other indicators of overt neuropathology. Whether microglial activation in seemingly healthy CNS tissue during the early stages of several is a response to early stages of neuronal or glial distress or an early sign of microglial dysfunction causing subsequent neurodegeneration is unknown. Here we characterize and discuss how changes in the CNS microenvironment (neuronal activity/viability, glial activation) lead to specific forms of microglial activation. Specifically, we examine the potential role that TREM-2 expressing microglia may play in regulating the effector function of autoreactive T cell responses. Thus, we suggest that ubiquitous suppression of microglial activation during CNS inflammatory disorders rather than targeted manipulation of microglial activation, may in the end be maladaptive leading to incomplete remission of symptoms.     

Hyper production of β-glucosidase by an Aspergillus sp.

Summary An Aspergillus sp. was isolated which secreted high levels of -glucosidase in growth medium. The maximum activity(10 IU/ml of -glucosidase and 22.6 IU/ml of cellobiase) was obtained in cellulose medium supplemented with wheat bran. The pH and temperature optima for this enzyme were 4.5 and 65°C respectively.NCL Communication No. 3616     

Redescriptions of Phallodrilus parthenopaeus Pierantoni and P. obscurus Cook (Oligochaeta, Tubificidae)

The type species of Phallodrilus Pierantoni, 1902, P. parthenopaeus Pierantoni, 1902; is redescribed on the basis of new material from W Scotland. The species is characterized by its specific spermathecal and penial setae, its very slender atria, and its long spermathecal ducts. Sexually fully mature specimens of P. obscurus Cook, 1969 are described for the first time, on the basis of material from New Jersey (E USA). The new material shows that this species possesses 5 to 9 penial setae in each ventral bundle of segment XI, and that its atria are coated with a relatively thick musculature.     

Marine Tubificidae (Oligochaeta) of Antarctica, with descriptions of three new species of Phallodrilinae

Five species of Tubificidae are recorded from Antarctic waters: Torodrilus lowryi Cook, 1970, Torodrilus sp. (subfamily Rhyacodrilinae), Marionidrilus antarcticus sp. n., M. weddellensis sp. n., and Thalassodrilus bicki sp. n. (subfamily Phallodrilinae); only T. lowryi was known from Antarctica before. The status of the two Southern Hemisphere genera Torodrilus Cook, 1970, and Marionidrilus Erséus, 1992, are discussed; although the taxonomic position of the two new species of Marionidrilus is somewhat uncertain. Thalassodrilus bicki , however, appears closely related to Northern Hemisphere taxa.