Retention of endocrine function by an insulin-secreting pancreatic islet cell tumour from Syrain hamster through serial transplantation in nude mice.

An insulin-secreting islet cell tumour of the Syrian hamster has been transplanted serially in the congenitally immune-deficient nude mouse, in order to test the potential usefulness of this mouse mutant as a graft carrier of heterologous tumours with stable differentiated phenotypes. The incidence of tumour growth was very high, and the hamster tumour retained its functional and histologic characteristics during consecutive passages in nude mice. These results show that nude mice may be useful carriers of differentiated tumours from non-inbred species including man, and for the isolation of cell lines from such tumours.     

Seasonality of the rocky intertidal amphipodOligochinus lighti in response to microenvironmental variables

Organisms of intertidal regions experience climatological factors of marine and non-marine origin. Ecological studies indicate that climatological factors of non-marine origin are of primary importance in determining the distribution and abundance of the gammarid amphipodOligochinus lighti as shown by a decrease in population density with increasing height in the intertidal and a decrease in the population density accompanying seasonal increases in exposure to non-marine climatic conditions. Non-marine climatic factors affectingOligochinus are changes in temperature, salinity or moisture content in the algal clump inhabited by the amphipod. The microclimate of the algal clump depends upon its position in the intertidal and on how its form modifies the climatic conditions occurring during exposure. The algal microclimate is related in a complex fashion to seasonal changes in the coastal macroclimate mediated by the irregular semidiurnal tidal cycles of the region. A regression model has been developed to predict population changes on the basis of climatic factors.Presented at the Seventh International Biometeorological Congress, 17–23 August 1975, College Park, Maryland, USA.     

The role of C3 as an opsonin in the early stages of infection.

In order to investigate the role of C3 in host defense in vivo, normal AKR/J mice, genetically deficient in C5, were depleted of serum C3 by the injection of purified cobra venom factor (CoVF). Concurrent with their C3 depletion, their serum opsonizing activity decreased to a level less than 20% of normal. When these mice were challenged with an intraperitoneal injection of pneumococci 2 hr after the CoVF treatment, the LD50 was from 30 to 80 times lower than the LD50 in saline-treated control animals. When the CoVF was given only 6 hr after the pneumococcal challenge, the LD50 was the same as in the control mice. If the pneumococci were first preopsonized in vitro and then injected into CoVF-treated animals, the LD50 was the same as that in control animals. These experiments demonstrate that C3 plays a significant role in vivo in the host's defense against infection and that a major part of that role is through its action as an opsonin. Furthermore, these experiments demonstrate that the role of C3 is most significant during the early stages of bacterial invasion.     

Genomic Shifts,Phenotypic Clines,and Fitness Costs Associated With Cold Tolerance in the Asian Tiger Mosquito

Climatic variation is a key driver of genetic differentiation and phenotypic traits evolution, and local adaptation to temperature is expected in widespread species. We investigated phenotypic and genomic changes in the native range of the Asian tiger mosquito, Aedes albopictus. We first refine the phylogeographic structure based on genome-wide regions (1,901 double-digest restriction-site associated DNA single nucleotide polymophisms [ddRAD SNPs]) from 41 populations. We then explore the patterns of cold adaptation using phenotypic traits measured in common garden (wing size and cold tolerance) and genotype–temperature associations at targeted candidate regions (51,706 exon-capture SNPs) from nine populations. We confirm the existence of three evolutionary lineages including clades A (Malaysia, Thailand, Cambodia, and Laos), B (China and Okinawa), and C (South Korea and Japan). We identified temperature-associated differentiation in 15 out of 221 candidate regions but none in ddRAD regions, supporting the role of directional selection in detected genes. These include genes involved in lipid metabolism and a circadian clock gene. Most outlier SNPs are differently fixed between clades A and C, whereas clade B has an intermediate pattern. Females are larger at higher latitude yet produce no more eggs, which might favor the storage of energetic reserves in colder climate. Nondiapausing eggs from temperate populations survive better to cold exposure than those from tropical populations, suggesting they are protected from freezing damages but this cold tolerance has a fitness cost in terms of egg viability. Altogether, our results provide strong evidence for the thermal adaptation of A. albopictus across its wide temperature range.     

Age‐related changes in mean corpuscular volumes in patients without anaemia: An analysis of large‐volume data from a single institute

Although the mean corpuscular volume (MCV) has been associated with various diseases, these associations in relation to the age‐related trends in MCV remain unclear. Therefore, we used a dataset with over one million values to identify the relationship between ageing and MCV changes. All laboratory data obtained between November 1998 and November 2019 at Chungbuk National University Hospital were retrospectively collected. After excluding cases with missing values for individual complete blood count parameters, outlier MCV values, and ages less than 1 year and more than 88 years, 977,335 MCV values were obtained from 309,393 patients. Principal component analysis of blood components with ages and analysis of the median value changes for each blood component across decade‐wise age groups were conducted to identify relationships between ageing and changes in blood components. The median values of MCV showed gradual increments with age. The linear relationship for patients aged 1–25 years had a larger slope than that for patients aged 26–88 years. For MCV, the equation for patients aged 1–25 years was 0.40*(age) + 81.24 in females and 0.45*(age) + 79.58 in males. The equation for patients aged 26–90 years was 0.04*(age) + 88.97 in females and 0.06*age + 88.30 in males. Among patients aged >40 years, the MCV value was higher in men than in women. Analysis of a large dataset showed that the MCV gradually increased with age and the linear relationship differed between patients aged 1–25 and 26–88 years.     

Current state and perspectives on erythropoietin production

Erythropoietin is a major regulator of erythropoiesis which maintains the body's red blood cell mass and tissue oxygenation at an optimum level. Recombinant human erythropoietin (rhEPO), which is a widely used therapeutic agent for the treatment of anemia and which represents one of the largest biopharmaceuticals markets, is produced from recombinant Chinese hamster ovary cells. rhEPO is a glycoprotein with complex glycan structure, which is responsible for its therapeutic efficacy, including the in vivo activity and half-life. In order to obtain an optimal and consistent glycoform profile of rhEPO and concurrently maintain a high production yield, various approaches in drug development and cell culture technology have been attempted. Recent advances in rhEPO production are classified into three types: the development of improved rhEPO molecules by protein engineering; improvement of production host cells by genetic engineering; and culture condition optimization by fine control of the production mode/system, process parameters, and culture media. In this review, we focus on rhEPO production strategies as they have progressed thus far. Furthermore, the current status of the market and outlook on rhEPO and its derivatives are discussed.     

A preliminary X-ray study of a refolded PTS EIIBfruc protein from Escherichia coli

The phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) catalyzes the phosphorylation and transportation of its sugar substrates. A sugar-specific enzyme II complex involved in the PTS finally functions to translocate substrates across the membrane. A PTS EIIB(fruc) protein, a fructose specific EIIB subunit, from Escherichia coli has been cloned, expressed, refolded, purified, and crystallized. The synchrotron data were collected to 2.6 A from the crystal of a selenomethionine substitute PTS EIIB(fruc) protein. The crystal belongs to the primitive trigonal space group P3(1)21, with unit-cell parameters of a = 33.4 A, b = 33.4 A, c = 154.0 A, and beta = 120.0 degrees . A full structure determination is under way to provide insights into the structure-function relationships of this protein.     

Root-tip diameters of woody species in subalpine Abies forest

We clarified the differences in root-tip diameter (RTD) among tree and shrub species in an Abies forest. To evaluate the effects of sampling month and tree size on RTD, we measured the root-tip diameters of mature individuals of nine woody species and sapling individuals of two Abies species in a subalpine Abies forest on Mount Shimagare in central Japan. Species, sampling month, and their interaction affected RTD; however, the differences in RTD between some pairs of species were consistent across sampling months. The woody species fell into two groups, based on RTD size: tree species with larger RTDs (group 1) and shrub species with smaller RTDs (group 2). Seasonal changes in RTD were observed in three species and showed different patterns among species. Tree size did not affect RTD for either Abies species; however, there was an interaction between tree size and sampling month for Abies veitchii. The woody species category had the greatest effect on RTD, followed by sampling month and then tree size.