Chimeric Arabidopsis thaliana Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Containing a Pea Small Subunit Protein Is Compromised in Carbamylation1

A cDNA of pea (Pisum sativum L.) RbcS 3A, encoding a small subunit protein (S) of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), has been expressed in Arabidopsis thaliana under control of the cauliflower mosaic virus 35S promoter, and the transcript and mature S protein were detected. Specific antibodies revealed two protein spots for the four Arabidopsis S and one additional spot for pea S. Pea S in chimeric Rubisco amounted to 15 to 18% of all S, as judged by separation on two-dimensional isoelectric focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels from partially purified enzyme preparations and quantitation of silver-stained protein spots. The chimeric enzyme had 11 ± 1% fewer carbamylated sites and a 11 ± 1% lower carboxylase activity than wild-type Arabidopsis Rubisco. Whereas pea S expression, preprotein transport, and processing and assembly resulted in a stable holoenzyme, the chimeric enzyme was reproducibly catalytically less efficient. We suggest that the presence of, on average, one foreign S per holoenzyme is responsible for the altered activity. In addition, higher-plant Rubisco, unlike the cyanobacterial enzyme, seems to have evolved species-specific interactions between S and the large subunit protein that are involved in carbamylation of the active site.

Substrate-specific regulation of the ribosome– translocon junction by N-terminal signal sequences

Amino-terminal signal sequences target nascent secretory and membrane proteins to the endoplasmic reticulum for translocation. Subsequent interactions between the signal sequence and components of the translocation machinery at the endoplasmic reticulum are thought to be important for the productive engagement of the translocon by the ribosome-nascent chain complex. However, it is not clear whether all signal sequences carry out these posttargeting steps identically, or if there are differences in the interactions directed by one signal sequence versus another. In this study, we find substantial differences in the ability of signal sequences from different substrates to mediate closure of the ribosome–translocon junction early in translocation. We also show that these differences in some cases necessitate functional coordination between the signal sequence and mature domain for faithful translocation. Accordingly, the translocation of some proteins is sensitive to replacement of their signal sequences. In a particularly dramatic example, the topology of the prion protein was found to depend highly on the choice of signal sequence used to direct its translocation. Taken together, our results reveal an unanticipated degree of substrate-specific functionality encoded in N-terminal signal sequences.

Xenopus Bcl-XL selectively protects Rohon-Beard neurons from metamorphic degeneration

Amphibian metamorphosis involves extensive, but selective, neuronal death and turnover, thus sharing many features with mammalian postnatal development. The antiapoptotic protein Bcl-XL plays an important role in postnatal mammalian neuronal survival. It is therefore of interest that accumulation of the mRNA encoding the Xenopus Bcl-XL homologue, termed xR11, increases abruptly in the nervous system, but not in other tissues, during metamorphosis in Xenopus tadpoles. This observation raises the intriguing possibility that xR11 selectively regulates neuronal survival during postembryonic development. To investigate this hypothesis, we overexpressed xR11 in vivo as a green fluorescent protein (GFP)-xR11 fusion protein by using somatic and germinal transgenesis. Somatic gene transfer showed that the fusion protein was effective in counteracting, in a dose-dependent manner, the proapoptotic effects of coexpressed Bax. When GFP-xR11 was expressed from the neuronal β-tubulin promoter by germinal transgenesis we observed neuronal specific expression that was maintained throughout metamorphosis and beyond, into juvenile and adult stages. Confocal microscopy showed GFP-xR11 to be exclusively localized in the mitochondria. Our findings show that GFP-xR11 significantly prolonged Rohon-Beard neuron survival up to the climax of metamorphosis, even in the regressing tadpole tail, whereas in controls these neurons disappeared in early metamorphosis. However, GFP-xR11 expression did not modify the fate of spinal cord motoneurons. The selective protection of Rohon-Beard neurons reveals cell-specific apoptotic pathways and offers approaches to further analyze programmed neuronal turnover during postembryonic development.

The dynamics of hepatitis B virus infection.

We consider a cellular model of infection by the hepatitis B virus and describe how it may be used to account for two important features of the disease, namely (i) the wide variety of manifestations of infection and the age dependence thereof, and (ii) the typically long delay before the development of virus-induced liver cancer (primary hepatocellular carcinoma). The model is based on the assumption that the liver is comprised of both immature and mature hepatocytes, with these two subpopulations of cells responding contrastingly upon infection by the virus.

High-affinity binding of Escherichia coli SecB to the signal sequence region of a presecretory protein.

The Escherichia coli cytosolic homotetrameric protein SecB is known to be involved in protein export across the plasma membrane. A currently prevalent view holds that SecB functions exclusively as a chaperone interacting nonspecifically with unfolded proteins, not necessarily exported proteins, whereas a contrary view holds that SecB functions primarily as a specific signal-recognition factor--i.e., in binding to the signal sequence region of exported proteins. To experimentally resolve these differences we assayed for binding between chemically pure SecB and chemically pure precursor (p) form (containing a signal sequence) and mature (m) form (lacking a signal sequence) of a model secretory protein (maltose binding protein, MBP) that was C-terminally truncated. Because of the C-terminal truncation, neither p nor m was able to fold. We found that SecB bound with 100-fold higher affinity to p (Kd 0.8 nM) than it bound to m (Kd 80 nM). As the presence of the signal sequence in p is the only feature that distinguished p from m, these data strongly suggest that the high-affinity binding of SecB is to the signal sequence region and not the mature region of p. Consistent with this conclusion, we found that a wild-type signal peptide, but not an export-incompetent mutant signal peptide of another exported protein (LamB), competed for binding to p. Moreover, the high-affinity binding of SecB to p was resistant to 1 M salt, whereas the low-affinity binding of SecB to m was not. These qualitative differences suggested that SecB binding to m was primarily by electrostatic interactions, whereas SecB binding to p was primarily via hydrophobic interactions, presumably with the hydrophobic core of the signal sequence. Taken together our data strongly support the notion that SecB is primarily a specific signal-recognition factor.

Is the date of birth an advantage/ally to excel in handball?

The Relative Age Effect (RAE) has been analyzed in a population of Spanish international handball players (n=161) divided into four different levels: Senior, Junior, Juvenile and Promising Talents. The variables registered were quarter, half year and year of birth using the initial information of their date of birth. The data were collected from the Royal Spanish Handball Federation on-line data base. The statistical method used was the χ2 and the minimum level of significance was set at p<0.05. The total results on distribution by quarter show a significant difference (χ2= 21.68; p<0.01) with a greater frequency of players born in the first quarter (40.37%) compared to those born in the second (22.36%), third (16.15%) and fourth quarter (21.12%). The total results on the distribution of birth date by half year show a significant difference (χ2= 10.44; p<0.01) with a greater frequency of players born in the first half of the year (62.73%). With regard to the rate of births registered in an even numbered or odd numbered year there are significant differences when the rates for an even numbered year (64.60%) and an odd numbered year (35.40%) are compared with those of the general population (χ2= 13.72; p<0.001). Based on the data collected and analyzed it can be concluded that there is a RAE in the basic categories of the Spanish national men’s handball teams according to quarter, half year and year of birth (even or odd numbered), but there exists little knowledge about the causes and consequence which may be produced by, or derive from, this effect.

A Book of Accounts beginning Feb. 26 1791, 1791-1799

The marbled-hardcover book contains three sections: a two column debit and credit entry section for students and tutors, a list of "the Bills of the Senior Class calculated" for 1793 and 1794, and at the end of the volume a personal accounting of expenses from February 1797 through January 1799 kept by Shapleigh during the time he was Harvard's Librarian, for services including mending, wood hauling, and "To Miss Morie for cleaning windows & washing sheets," as well as purchases such as books, coffee, and theater tickets.

Letter from Samuel Willard, Cambridge, Massachusetts, to William Willard, Petersham, Massachusetts, November 22, 1799

Willard details his various expenses for food, wood, tuition, and books, and explains his bill payment schedule. He also mentions President Willard and sends best wishes to his mother, brother, and sister.

The G-20 in the aftermath of the crisis: a Euro-Asian view. Bruegel Policy Brief, 24 March 2009

In 2009 the global economy switched from recession to recovery. However, the pace of the recovery has been very different in different parts of the world, with the divergence between emerging and mature economies becoming greater than expected. Europe and emerging Asia are in this respect in clearly opposite situations, while the Japanese situation is closer to that of Europe than to those of its neighbours (Figure 1 on the next page).

Lightweight Internet Traffic Classification - A Subject Based Solution with Word Embeddings

Internet traffic classification is a relevant and mature research field, anyway of growing importance and with still open technical challenges, also due to the pervasive presence of Internet-connected devices into everyday life. We claim the need for innovative traffic classification solutions capable of being lightweight, of adopting a domain-based approach, of not only concentrating on application-level protocol categorization but also classifying Internet traffic by subject. To this purpose, this paper originally proposes a classification solution that leverages domain name information extracted from IPFIX summaries, DNS logs, and DHCP leases, with the possibility to be applied to any kind of traffic. Our proposed solution is based on an extension of Word2vec unsupervised learning techniques running on a specialized Apache Spark cluster. In particular, learning techniques are leveraged to generate word-embeddings from a mixed dataset composed by domain names and natural language corpuses in a lightweight way and with general applicability. The paper also reports lessons learnt from our implementation and deployment experience that demonstrates that our solution can process 5500 IPFIX summaries per second on an Apache Spark cluster with 1 slave instance in Amazon EC2 at a cost of $ 3860 year. Reported experimental results about Precision, Recall, F-Measure, Accuracy, and Cohen's Kappa show the feasibility and effectiveness of the proposal. The experiments prove that words contained in domain names do have a relation with the kind of traffic directed towards them, therefore using specifically trained word embeddings we are able to classify them in customizable categories. We also show that training word embeddings on larger natural language corpuses leads improvements in terms of precision up to 180%.

Escala y talla de primera madurez gonadal en “NAVAJA” Tagelus dombeii (Lamarck, 1818), entre las zonas Parachique - Las Delicias, 2009

Para el estudio de la gametogénesis, escala de madurez y estimación de la talla de primera madurez gonadal de “navaja” Tagelus dombeii, las muestras procedieron de las zonas Caleta de Parachique y Las Delicias, y fueron colectadas a bordo de embarcaciones marisqueras por buzos artesanales, durante Enero – Diciembre del año 2009. La zona para tomar las muestras comprendieron desde los grados 05º 40' 33.3'' (LS) hasta 05º 49' 21.8'' (LS). En el estudio de la gametogénesis, se observó que los ovarios presentaron tres tipos de ovocitos: ovocito inmaduro (OI), ovocito en maduración (OEM) y ovocito maduro (OM), además del ovocito atrésico (OA) para las hembras, mientras que para los machos las células sexuales encontradas fueron: espermatogonio = SG, espermatocito = SC y espermatozoide = SP. La escala microscópica de madurez gonadal para “navaja” T. dombeii fue establecida con seis estadios, siendo estos: Virginal = 0, Reposo = I, En Maduración = II, Maduro =III, Desovante/Expulsante = IV y Recuperación = V. Así mismo, se estableció, que la talla de primera madurez gonadal es de 61 mm de longitud total (LT) para las hembras y 58 mm para machos, obteniendo un promedio de 58 mm LT. Mientras que la talla de primer desove/expulsión fue de: 67 mm (LT) para hembras y 66 mm LT para machos siendo promedio para ambos sexos de 66 mm LT. Además, se reporta la capacidad de T. dombeii de cambiar el sexo de hembra a macho (hermafroditismo protógino).

Asentamiento y reclutamiento de poliquetos bentónicos en la plataforma continental frente a Callao desde verano a invierno de 2015

La diversidad en los estadios de desarrollo de los poliquetos bentónicos fue estudiada en un perfil batimétrico de la plataforma continental central frente a Callao (Perú, 12°S) del verano al invierno del 2015, con el objetivo de determinar el asentamiento de larvas y reclutamiento de poliquetos bentónicos, bajo la influencia de los factores abióticos del agua y sedimento: temperatura, salinidad, oxígeno disuelto de fondo, sulfuro de hidrógeno en agua intersticial, fitopigmentos totales, materia orgánica total y biopolímeros lábiles. Se encontró un total de 25 especies, pertenecientes a 15 familias. La familia Spionidae presentó la mayor diversidad de larvas (06 especies), seguida de la familia Pilargidae (03 especies). Las larvas de Magelonidae fueron dominantes en verano y otoño. La disponibilidad larval en la capa de fondo estuvo asociada al régimen de oxigenación en el gradiente batimétrico. El número de larvas de poliquetos disminuyó desde el ambiente somero hacia la plataforma externa. Asimismo, la abundancia total de larvas de poliquetos y la abundancia de larvas de Magelona phyllisae se redujeron con el aumento de la temperatura y de la profundidad de la oxiclina durante el período de estudio, caracterizado por la influencia del evento El Niño 2015 - 2016. Por otro lado, se encontró que el número de especies de poliquetos juveniles y adultos fue mayor en ambientes someros, con mayor grado de oxigenación pero también condiciones más reductoras en el sedimento. No obstante, el éxito del reclutamiento, inferido a partir de la abundancia de individuos adultos y la proporción entre el número de especies en estadio adulto y el estadio juvenil fueron mayores en la plataforma externa deficiente en oxígeno, lo cual fue explicado principalmente por la contribución de Paraprionospio pinnata, especie dominante y típica de sedimentos de la plataforma continental.

(Table T3) Vitrinite reflection of samples obtained from ODP Leg 180 sites

Seventy-one samples from Ocean Drilling Program Leg 180 sites were analyzed for vitrinite reflectance and organic type. The objective was to define maximum paleotemperatures across the western Woodlark Basin as a function of depth. The organic matter is of early Pliocene to Holocene age and was recovered from drilled depths of 4.5 to 851.3 meters below seafloor. Organic matter is generally restricted to woody fragments within the sediment, although in a number of fine-grained samples, organic matter is dispersed throughout the sample. Virtually all samples contain vitrinite, part of which may be derived from drifted logs. One sample was found to be barren of organic matter, and two contain only fusinite and semifusinite. Variation of vitrinite reflectance is not systematic with either depth or location, and it appears that formation temperatures have been insufficient to cause an increase in vitrinite reflectance levels. Textural variations within the vitrinite show better correlation with depth. Samples of hypautochthonous peats represent either a terrestrial phase of sedimentation or large peat intraclasts within the section, possibly produced by forest fires in the source areas of the organic matter. The vitrinite and peat-derived samples appear to come from eucalyptus forest settings away from the coastline. Liptinite is not abundant in most of the samples (excluding suberinite associated with woody tissues). Marine liptinite is rare to absent, although many of the samples contain abundant foraminiferal tests. Pyrite is abundant in many of the wood fragments, and some pyritization of woody tissues has taken place.

British manufactures.

[Vols. 4-6] are called "Series IV-VI."

Practical instrumentation /

Pt. 1. The strings.--Pt. 2. The wood-wind.--Pt. 3. Strings and wood-wind combined.--Pt. 4. The horns.--Pt. 5. The combination of strings, wood-wind and horns.--Pt. 6. The trumpets, cornets, trombones, tubas and instruments of percussion.--Pt. 7. Harp, mandoline, zither, guitar, piano (cembalo), organ and harmonium.