The protein cost of metabolic fluxes: prediction from enzymatic rate laws and cost minimization

Bacterial growth depends crucially on metabolic fluxes, which are limited by the cell's capacity to maintain metabolic enzymes. The necessary enzyme amount per unit flux is a major determinant of metabolic strategies both in evolution and bioengineering. It depends on enzyme parameters (such as kcat and KM constants), but also on metabolite concentrations. Moreover, similar amounts of different enzymes might incur different costs for the cell, depending on enzyme-specific properties such as protein size and half-life. Here, we developed enzyme cost minimization (ECM), a scalable method for computing enzyme amounts that support a given metabolic flux at a minimal protein cost. The complex interplay of enzyme and metabolite concentrations, e.g. through thermodynamic driving forces and enzyme saturation, would make it hard to solve this optimization problem directly. By treating enzyme cost as a function of metabolite levels, we formulated ECM as a numerically tractable, convex optimization problem. Its tiered approach allows for building models at different levels of detail, depending on the amount of available data. Validating our method with measured metabolite and protein levels in E. coli central metabolism, we found typical prediction fold errors of 3.8 and 2.7, respectively, for the two kinds of data. ECM can be used to predict enzyme levels and protein cost in natural and engineered pathways, establishes a direct connection between protein cost and thermodynamics, and provides a physically plausible and computationally tractable way to include enzyme kinetics into constraint-based metabolic models, where kinetics have usually been ignored or oversimplified

Direct measurements of the effect of biomass burning over the Amazon on the atmospheric temperature profile

Aerosols suspended in the atmosphere interact with solar radiation and clouds, thus change the radiation energy fluxes in the atmospheric column. In this paper we measure changes in the atmospheric temperature profile as a function of the smoke loading and the cloudiness, over the Amazon basin, during the dry seasons (August and September) of 2005–2008. We show that as the aerosol optical depth (AOD) increases from 0.02 to a value of ~0.6, there is a decrease of ~4°C at 1000 hPa, and an increase of ~1.5°C at 850 hPa. The warming of the aerosol layer at 850 hPa is likely due to aerosol absorption when the particles are exposed to direct illumination by the sun. The large values of cooling in the lower layers could be explained by a combination of aerosol extinction of the solar flux in the layers aloft together with an aerosol-induced increase of cloud cover which shade the lower atmosphere. We estimate that the increase in cloud fraction due to aerosol contributes about half of the observed cooling in the lower layers

Exílio sul-americano em Israel (1973-1978)

In order to escape from the repression of military dictatorships in Argentina, Chile and Uruguay, hundreds of citizens went into exile in Israel. The majority of them didn’t have any relation with Zionism. The present article describes the fight of these exiles against the dictatorships in their countries and the officialpolicies in Israel, which had cordial relationships with the military governments in South America.Para escapar da repressão das ditaduras militares em seus países, argentinos, chilenos e uruguaios buscaram exílio em Israel. A maioria deles não tinha ligação com o sionismo. O presente artigo descreve a luta desses exilados contra os ditadores de seus países e contra a política oficial de Israel, que mantinha relaçõescordiais com os governos militares sulamericanos

PELATIHAN DAN PUSAT UMKM DI UNGARAN

UMKM saat ini telah menjadi pilar terpenting dalam perekonomian Indonesia sehingga sudah tidak bisa dipandang sebelah mata dimana berdasarkan data Kementerian Koperasi dan UKM, jumlah UMKM terbaru pada tahun 2021 telah mencapai 64,2 juta. Di Jawa Tengah tepatnya di Kabupaten Semarang, berdasarkan hasil wawancara dengan Dinas Koperasi, Usaha Mikro, Perindustrian dan Perdagangan Kabuopaten Semarang, jumlah UMKM di Kabupaten Semarang pada tahun 2016 mencapai sekitar 83.000. Untuk jenis UMKM di Kabupaten Semarang sendiri memiliki jenis yang beragam dan dibagi menjadi 4 klaster diantaranya: klaster kemasan kering, klaster kuliner, klaster craft serta klaster fashion. Dari 4 klaster tersebut, UMKM yang paling mendominasi di Ungaran yaitu klaster kuliner. Akan tetapi, untuk permasalahan yang masih dihadapi para pelaku UMKM di Kabupaten Semarang hingga saat ini yaitu belum adanya ruang pajang / outlet. Hal tersebut dapat dilihat pada portal berita Info Publik tahun 2018 dimana ada 300 pelaku UMKM yang tergabung dalam koperasi “UMKM Center” di Kabupaten Semarang belum memiliki ruang pajang / outlet. Di samping itu, untuk saat ini para pelaku UMKM sudah memiliki tempat untuk pelatihan dan konsultasi bernama PLUT (Pusat Layanan Usaha Terpadu) namun dikarenakan lahan yang terbatas maka ruang pajang yang sudah ada juga belum optimal. Dengan adanya permasalahan yang dihadapi, maka untuk mengatasi permasalahan tersebut, diperlukan solusi yang tepat dan salah satu solusi yang dapat dilakukan yaitu dengan mendirikan Pelatihan dan Pusat UMKM dimana dalam satu bangunan ini akan memiliki 2 fungsi sekaligus yaitu berupa pelatihan dan ruang pajang / outlet. Untuk pendekatan yang akan digunakan pada bangunan Pelatihan dan Pusat UMKM di Ungaran yaitu akan menyesuaikan dengan potensi lokal yang ada di Ungaran / Kabupaten Semarang. Dengan adanya bangunan Pelatihan dan Pusat UMKM di Ungaran diharapkan dapat menjadi wadah bagi pelaku UMKM dalam mempromosikan produk yang dibuat serta dapat memajukan UMKM yang ada di Kabupaten Semarang terutama di Ungaran

Tick control in Tswana, Simmental and Brahman cattle by means of Neem seed extracts (Azadirachta indica)

Please read the abstract in the section 00front of this documentDissertation (MSc Agric (Animal Science))--University of Pretoria, 2006.Animal and Wildlife Sciencesunrestricte

Observational bounds on atmospheric heating by aerosol absorption: Radiative signature of transatlantic dust

[1] Aerosols absorb solar radiation thus changing the atmospheric temperature profile but the overall magnitude of this effect is not known. To that end, Saharan dust emissions over the Atlantic Ocean provide an opportunity to examine aerosol‐related heating via satellite imaging. A major difficulty, however, is disentangling a straightforward heating signal caused by the absorbing dust from a meteorological signal, which originates from correlation between dust concentration and air temperature. To tackle the problem, we combine temperature (T) soundings, from the atmospheric infrared sounder (AIRS), with aerosol optical depth (τ) measurements, from the moderate resolution imaging spectroradiometer (MODIS), and data assimilation results from the global data assimilation system (GDAS). We introduce the quantity β(P) ≡ ∂TP/∂τ, the subscript indicating temperature at a given pressure, and study the observed (AIRS) vs. modeled (GDAS) vertical profiles of β(P). Using the vertical as well as horizontal patterns of β(P) and Δβ(P) ≡ βobs. − βmodl., we avoid instrumental and geographic artifacts and extract a remarkably robust radiative heating signal of about 2–4 K within the dust layer. The extracted signal peaks over the mid‐Atlantic Ocean, as a result of competing trends: “memory” of the dust source in the east, and mixing with transparent aerosol in the west