Recent decrease in carbon sink to Russian forests

Regional Evaluation of Carbon Budget of Forests (RECBF), was used to study the dynamics of carbon balance in Russian forests in 1988–2015. The carbon sink (excess of absorption over losses) to forests was minimal in 1988. Since the first half of the 1990s, its increase has started. This increase was associated with the reduction of logging volume in connection with socioeconomic reforms. Since 2008, the carbon sink was gradually reduced due to increasing losses in logging operations, forest fires, and decreased carbon absorption.     

BOOK REVIEWS

Book reviewed in this article:
P hysical A nthropology : Yearbook of Physical Anthropology, 1947. G abriel W. L asker and J. L awrence A ngel
Yearbook of Physical Anthropology, 1948. G abriel W. L asker and F rederick P. T hieme     

In vitro stabilization of 6-methylsalicylic acid synthetase from Penicillium urticae

In continuing studies of patulin biosynthesis, the first enzyme of the pathway, 6-methylsalicylic acid synthetase, was found to be far more labile than were the later enzymes of the pathway. Attempts were made to stabilize 6-methylsalicylic acid synthetase in vitro. The combined addition of the cofactor NADPH, the substrates acetyl-CoA and malonyl-CoA, the reducing agent dithiothreitol, and the proteinase inhibitor phenylmethylsulfonyl fluoride to cell-free extracts was found to prolong the half-life of the enzyme as much as 12-fold. This suggested that proteolysis and the conformational integrity of the enzyme may play an important role in controlling the duration of antibiotic biosynthesis in vivo. This was in agreement with the finding that the intracellular proteinase content of antibiotic-producing cells of Penicillium urticae rapidly increased just before the loss of 6-methylsalicylic acid synthetase content. These in vitro stabilization studies have provided some insight into the metabolic conditions that may stabilize these enzymes in vivo, and into possible ways of extending the life of these catalysts.     

Plasmacytoma of the breast. Unusual initial presentation of myeloma: report of two cases and review of the literature

Two patients who presented initially with breast masses proven to be plasmacytomas, are described. In both cases the breast masses led to the diagnosis of multiple myeloma, which was retrospectively already present at the time of the breast biopsy. One patient with IgG lambda-type myeloma developed plasma cell leukemia and amyloidosis and failed to respond to radiochemotherapy. The second patient was in complete remission, four years after therapy, but has subsequently relapsed and died. All cases of breast plasmacytoma, described in the medical literatures are reviewed, and guidelines for future therapy are suggested.     

Measurements of electron spin resonance with the pyruvate dehydrogenase complex from Escherichia coli. Studies on the allosteric binding site of acetyl-coenzyme A

Binding of the feedback inhibitor acetyl-coenzyme A to the pyruvate dehydrogenase complex from Escherichia coli was studied by electron spin resonance spectroscopy with the spin-labelled acetyl-CoA analogue 3-carboxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl-CoA-thioester. The spin-labelled compound binds to the pyruvate dehydrogenase component of the enzyme complex and this binding can be reversed by acetyl-CoA, while CoA has no effect. AMP and fructose 1,6-bisphosphate, which are both activators of the pyruvate dehydrogenase complex, exhibit a partial competition with the spin-labelled acetyl-CoA analogue and it could be shown that both activators act essentially by reversion of the feedback inhibition of acetyl-CoA. The binding site for these activators seems to overlap with the acetyl-CoA binding site, possibly by a common phosphate attachment point. No competition for binding to the feedback inhibition site exists with pyruvate, thiamine diphosphate, magnesium ions and with the fluorescent chromophore 8-anilino-1-naphthalene sulfonic acid. Thus, the feedback inhibition site proves to be a true allosteric regulatory site, which appears to be completely separate from the catalytic site on the pyruvate dehydrogenase component. The spin-labelled acetyl-CoA analogue binds also to the product binding site of acetyl-CoA on the dihydrolipoamide acetyltransferase component of the pyruvate dehydrogenase complex. Two binding sites per polypeptide chain with identical affinities on this enzyme component were found and the binding of the analogue can be inhibited by acetyl-CoA as well as by CoA.     

H-2-linked genetic control of the plaque-forming cell response to sheep red blood cells

The role of genes linked to the H-2 locus in effecting an immune response to SRBC was examined using strains of mice which differ in the classes of antibodies produced following multiple injections with SRBC. While H-2-linked gene action appeared to be at the level of regulating the number of plaque-forming cells (PFC) present in the spleens of different strains following two injections with SRBC, non-H-2-linked immune response genes seemed to determine whether an IgM-IgG switch occurred as well as how much of each antibody class was produced by the number of PFC available as a result of H-2-linked gene intervention. Mapping studies showed that the H-2-linked genetic effects were due to either the requirement for two genes or the presence of genes located between I-B and H-2D.     

Ultrastructural alteration of cytolytic T lymphocytes following their interaction with target cells. I. Hypertrophy and change of orientation of the Golgi apparatus.

The ultrastructure of cytolytic T lymphocytes adhered to the surface of target cells was investigated at different periods after start of interaction. Fifteen-minute incubation led to increase of number of Golgi apparatus cisternae and vacuoles. After 30 min incubation Golgi apparatus become oriented to the contact area. If several lymphocytes adhered to one target cell the Golgi apparatus of each of them was oriented toward the contact area. If one lymphocyte adhered simultaneously to two target cells its Golgi apparatus was oriented toward both target cells. Giant Golgi apparatus vacuoles were formed 30 to 60 min later and then moved to plasma membrane of lymphocyte and then the content of those vacuoles moved to the intercellular space between a cytolytic T lymphocyte and a target cell. The period required for the hypertrophy and change of orientation of Golgi apparatus is supposed to represent the “mobilization” step of a medium-sized and small killer lymphocyte.     

Genetic analysis of hypertropic mutants of Phycomyces

A new class of Phycomyces behavioral mutants with enhanced tropic responses has been analyzed genetically to determine the number of genes involved and the nature of their expression. These hypertropic mutants carry pleiotropic nuclear mutations. Besides their effects on sensory behavior, they also affect morphology and meiotic processes. Behavioral analyses of heterokaryons containing hypertropic and wild-type nuclei in varying proportions show that the hypertropic mutations in strains L82, L84, L86, and L88 are strongly dominant. Conversely, the hypertropic mutations carried by the strains L83, L85, and L87 are strongly recessive. We performed recombination analyses between hypertropic mutants and mutants with diminished phototropism, affected in the seven genes madA to madG. We found no evidence of linkage between the hypertropic mutations and any of these mad mutations. From crosses, we isolated double mutants carrying hypertropic mutations together with madC (night blind) and madG (stiff) mutations. The behavioral phenotypes of the double mutants are intermediate between those of the parentals. Complementation analyses show that the three recessive hypertropic mutations affect the same gene, which we call madH. The expression of the recessive hypertropic allele becomes dominant in heterokaryons carrying madC and madH nuclei; the madC gene has been implicated separately with the photoreceptor at the input to the sensory pathway, while the madH gene is associated with the growth control output. This result suggests the physical interaction of both gene products, madH and madC, in a molecular complex for the photosensory transduction chain.