Comparison of Three Inbred Mouse Strains with Respect to General and Genetic Radiosensitivity

The radiosensitivities of three mouse strains (BALB/cLacY, C3H/SnY, and 101/HY) have been compared using the following parameters: survival after irradiation at a dose of 6–7 Gy, chromosome aberration frequency in bone marrow cells after irradiation at a dose of 1.5 Gy, and the change in testis weight and frequency of abnormal sperm heads (ASHs) after irradiation at doses from 0.5 to 4 Gy. Strain BALB/c is the most radiosensitive with respect to the survival and chromosome aberration frequency in the bone marrow but the most resistant with respect to the change in testis weight and the frequency of abnormal sperm heads. Strain 101/HY was the most resistant with respect to survival and chromosome aberration frequency in bone marrow after irradiation but the most radiosensitive with respect to testis damage.     

Morphologically cryptic biological species within the liverwort Frullania asagrayana

? Premise of the study: The Frullania tamarisci complex includes eight Holarctic liverwort species. One of these, F. asagrayana, is distributed broadly throughout eastern North America from Canada to the Gulf Coast. Preliminary genetic data suggested that the species includes two groups of populations. This study was designed to test whether the two groups are reproductively isolated biological species. ? Methods: Eighty-eight samples from across the range of F. asagrayana, plus 73 samples from one population, were genotyped for 13 microsatellite loci. Sequences for two plastid loci and nrITS were obtained from 13 accessions. Genetic data were analyzed using coalescent models and Bayesian inference. ? Key results: Frullania asagrayana is sequence-invariant at the two plastid loci and ITS2, but two clear groups were resolved by microsatellites. The two groups are largely reproductively isolated, but there is a low level of gene flow from the southern to the northern group. No gene flow was detected in the other direction. A local population was heterogeneous but displayed strong genetic structure. ? Conclusions: The genetic structure of F. asagrayana in eastern North America reflects morphologically cryptic differentiation between reproductively isolated groups of populations, near-panmixis within groups, and clonal propagation at local scales. Reproductive isolation between groups that are invariant at the level of nucleotide sequences shows that caution must be exercised in making taxonomic and evolutionary inferences from reciprocal monophyly (or lack thereof) between putative species.     

Genome sequence of the lignocellulose degrading fungus Phanerochaete chrysosporium strain RP78

White rot fungi efficiently degrade lignin, a complex aromatic polymer in wood that is among the most abundant natural materials on earth. These fungi use extracellular oxidative enzymes that are also able to transform related aromatic compounds found in explosive contaminants, pesticides and toxic waste. We have sequenced the 30-million base-pair genome of Phanerochaete chrysosporium strain RP78 using a whole genome shotgun approach. The P. chrysosporium genome reveals an impressive array of genes encoding secreted oxidases, peroxidases and hydrolytic enzymes that cooperate in wood decay. Analysis of the genome data will enhance our understanding of lignocellulose degradation, a pivotal process in the global carbon cycle, and provide a framework for further development of bioprocesses for biomass utilization, organopollutant degradation and fiber bleaching. This genome provides a high quality draft sequence of a basidiomycete, a major fungal phylum that includes important plant and animal pathogens.     

The Estimation of Molecular and Cytogenetic Effects in Mice Exposed to Chronic Low Dose-Rate Gamma-Radiation

Molecular and cytogenetic parameters were estimated in male CBA/lac mice exposed to chronic low dose-rate -radiation (62 cGy/year) for 40, 80, 120, 210, and 365 days. After 40 days of exposure (6.7 cGy), spleen lymphocyte susceptibility to hydrogen peroxide was shown to increase. However, beginning from the day 120 of the treatment (20.4 cGy), the opposite effect was observed. An increase in number of the DNA–protein crosslinks was recorded in spleen lymphocytes only on day 40 of the experiment. The number of DNA breaks increased significantly beginning from day 120 of the experiment, as shown by the DNA-comet method. On the day 210 of irradiation, the frequency of abnormal sperm heads in the mice significantly increased. The number of normochromatic micronucleated erythrocytes of the peripheral blood remained unchanged.     

Use of Medical Services and Medicines Attributable to Diabetes in Sub-Saharan Africa

Background

Although the large majority of persons with diabetes and other non-communicable diseases (NCDs) lives and dies in low- and middle-income countries, the prevention and treatment of diabetes and other NCDs is widely neglected in these areas. A contributing reason may be that, unlike the impacts of acute and communicable diseases, the demands on resources imposed by diabetes is not superficially obvious, and studies capable of detecting these impacts have not be done.

Methods

To ascertain recent use of medical services and medicines and other information about the impact of ill-health, we in 2008–2009 conducted structured, personal interviews with 1,780 persons with diagnosed diabetes (DMs) and 1,770 matched comparison subjects (MCs) without diabetes in Cameroon, Mali, Tanzania and South Africa. We sampled DMs from diabetes registries and, in Cameroon and South Africa, from attendees at outpatient diabetes clinics. To recruit MCs, we asked subjects with diabetes to identify five persons living nearest to them who were of the same sex and approximate age. We estimated diabetes impact on medical services use by calculating ratios and differences between DMs and MCs, testing for statistical significance using two-stage multivariable hurdle models.

Findings

DMs consumed 12.95 times more days of inpatient treatment, 7.54 times more outpatient visits, and 5.61 times more medications than MCs (all p<0.001). DMs used an estimated 3.44 inpatient days per person per year, made 10.72 outpatient visits per person per year (excluding traditional healers), and were taking an average of 2.49 prescribed medicines when interviewed.

Conclusions

In Sub-Saharan Africa, the relative incremental use of medical care and medicines associated with diagnosed diabetes is much greater than in industrialized countries and in China. Published calculations of the health-system impact of diabetes in Africa are dramatic underestimates. Although non-communicable diseases like diabetes are commonly thought to be minor problems for health systems and patients in Africa, our data demonstrate the opposite.     

Molecular Adaptations Allow Dynein to Generate Large Collective Forces inside Cells

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Highlights? Ensemble function of motors inside cells measured at single-motor resolution ? Teams of dynein motors can generate large persistent forces, but kinesins cannot ? Dyneins take differentially sized steps to bunch together and share load better ? Against high load, dynein teams catch bond to microtubules and resist detachment     

Complete genome sequence of the industrial bacterium Bacillus licheniformis and comparisons with closely related Bacillus species

Background

Bacillus licheniformis is a Gram-positive, spore-forming soil bacterium that is used in the biotechnology industry to manufacture enzymes, antibiotics, biochemicals and consumer products. This species is closely related to the well studied model organism Bacillus subtilis, and produces an assortment of extracellular enzymes that may contribute to nutrient cycling in nature.

Results

We determined the complete nucleotide sequence of the B. licheniformis ATCC 14580 genome which comprises a circular chromosome of 4,222,336 base-pairs (bp) containing 4,208 predicted protein-coding genes with an average size of 873 bp, seven rRNA operons, and 72 tRNA genes. The B. licheniformis chromosome contains large regions that are colinear with the genomes of B. subtilis and Bacillus halodurans, and approximately 80% of the predicted B. licheniformis coding sequences have B. subtilis orthologs.

Conclusions

Despite the unmistakable organizational similarities between the B. licheniformis and B. subtilis genomes, there are notable differences in the numbers and locations of prophages, transposable elements and a number of extracellular enzymes and secondary metabolic pathway operons that distinguish these species. Differences include a region of more than 80 kilobases (kb) that comprises a cluster of polyketide synthase genes and a second operon of 38 kb encoding plipastatin synthase enzymes that are absent in the B. licheniformis genome. The availability of a completed genome sequence for B. licheniformis should facilitate the design and construction of improved industrial strains and allow for comparative genomics and evolutionary studies within this group of Bacillaceae.     

Genetic effects of radiocarbon in reproductive cells of male mice

The genetic effect of incorporated radiocarbon was studied after single, long-term (33 days) and chronic (6 and 12 months) treatment of male mice (CBA X C57B1) F1 with [14C]glucose. The genetic effect in male germ cells was estimated by 3 tests: DLM frequency in post- and pre-meiotic cells, RT frequency in stem spermatogonia and frequency of abnormal sperm heads. Absorbed doses in the gonads were: 0.22, 0.50 and 1.01 Gy, after a single exposure; 0.74 and 1.47 Gy, after long-term exposures; and 0.006 and 0.031 Gy, after chronic exposure for 6 months; and 0.013 and 0.066 Gy, for 12 months. The results suggest that DLM frequency in post-meiotic cells increased linearly with increasing the dose of 14C single and long-term exposures at a dose of 1.47 Gy only. A chronic treatment with [14C]glucose induced no increase in DLM frequency. RT frequency in stem spermatogonia was statistically significantly higher than the control level after the single and long-term exposure to 14C. A comparison of the results with the results of external single and chronic gamma-irradiation allows the conclusion that the relative genetic efficiency of radiocarbon as compared with that of gamma-rays is about 1.     

A cross-sectional study of the microeconomic impact of cardiovascular disease hospitalization in four low- and middle-income countries

Objective

To estimate individual and household economic impact of cardiovascular disease (CVD) in selected low- and middle-income countries (LMIC).

Background

Empirical evidence on the microeconomic consequences of CVD in LMIC is scarce.

Methods and Findings

We surveyed 1,657 recently hospitalized CVD patients (66% male; mean age 55.8 years) from Argentina, China, India, and Tanzania to evaluate the microeconomic and functional/productivity impact of CVD hospitalization. Respondents were stratified into three income groups. Median out-of-pocket expenditures for CVD treatment over 15 month follow-up ranged from 354 international dollars (2007 INT$, Tanzania, low-income) to INT$2,917 (India, high-income). Catastrophic health spending (CHS) was present in >50% of respondents in China, India, and Tanzania. Distress financing (DF) and lost income were more common in low-income respondents. After adjustment, lack of health insurance was associated with CHS in Argentina (OR 4.73 [2.56, 8.76], India (OR 3.93 [2.23, 6.90], and Tanzania (OR 3.68 [1.86, 7.26] with a marginal association in China (OR 2.05 [0.82, 5.11]). These economic effects were accompanied by substantial decreases in individual functional health and productivity.

Conclusions

Individuals in selected LMIC bear significant financial burdens following CVD hospitalization, yet with substantial variation across and within countries. Lack of insurance may drive much of the financial stress of CVD in LMIC patients and their families.