Ingestion without inactivation of bacteriophages by Tetrahymena

Tetrahymena has been shown to ingest and inactivate bacteriophages, such as T4, in co-incubation experiments. In this study, Tetrahymena thermophila failed to inactivate phages PhiX174 and MS2 in co-incubations, although PhiX174 were ingested by T. thermophila, as demonstrated by: (1) recovery at defecation in a pulse-chase experiment, (2) recovery from Tetrahymena by detergent lysis, and (3) transmission electron microscopy. We conclude, therefore, that the phages must be digestion-resistant. Internalized PhiX174 were further shown to be partially protected from lethal damage by ultraviolet (UV) C and UVB irradiation. Finally, ingested PhiX174 were shown to be rapidly transported through buffer in a horizontal swimming, race tube-like assay. The transport and protection of phages may confer evolutionary advantages that explain the acquisition of digestion-resistance by some phages.     

The paramutagenic line niv-44 has a 5 kb insert, Tam 2, in the chalcone synthase gene of Antirrhinum majus

Summary Several alleles of the nivea locus of Antirrhinum majus, both stable and unstable, have been characterised genetically (Harrison and Carpenter 1973 a, b). In this work the niv-44 allele is characterised at the molecular level. It contains a 5kb insertion element, Tam 2, which has 14 base pair inverted repeats. There is a three base pair duplication at the target site, which is at the first intron-exon boundary of the chalcone synthase gene. Tam 2 homologous sequences are present in multiple copies in several A. majus lines, including niv-53, and most have at least a 2.9 kb sequence in common with the copy at the chalcone synthase gene. Possible reasons for the apparent stability of the niv-44 allele and molecular explanations for the role of this allele in paramutation in A. majus are discussed.Dedicated to Professor Georg Melchers to celebrate his 50-year association with the journal     

Identification of a Serratia entomophila genetic locus encoding amber disease in New Zealand grass grub (Costelytra zealandica).

Serratia entomophila UC9 (A1MO2), which causes amber disease in the New Zealand grass grub Costelytra zealandica, was subjected to transposon (TnphoA)-induced mutagenesis. A mutant (UC21) was found to be nonpathogenic (Path-) to grass grub larvae in bioassays and was shown, by Southern hybridization, to contain a single TnphoA insertion. This mutant failed to adhere to the gut wall (Adn-) of the larvae and also failed to produce pili (Pil-). A comparative study of the total protein profiles of wild-type S. entomophila UC9 and mutant UC21 revealed that the mutant lacked an approximately 44-kDa protein and overexpressed an approximately 20-kDa protein. Transfer of cosmids containing homologous wild-type sequences into mutant strain UC21 restored wild-type phenotypes (Path+, Pil+, and Adn+). One of the complementing cosmids (pSER107) conferred piliation on Pil- Escherichia coli HB101. The TnphoA insertion in UC21 was mapped within an 8.6-kb BamHI fragment common to the complementing cosmids, and we designated this gene locus amb-1. Six gene products with molecular masses of 44, 36, 34, 33, 20, and 18 kDa were detected in E. coli minicells exclusive to the cloned 8.6-kb fragment (pSER201A). The 44-kDa gene product was not detected in E. coli minicells containing the cloned mutant fragment. Saturation mutagenesis of this fragment produced four unlinked insertional mutations with active fusions to TnphoA. These active fusions disrupted the expression of one or more gene products encoded by amb-1. The 8.6-kb fragment cloned in the opposite orientation (pSER201B) expressed only a 20-kDa protein. We propose that these are the products of structural and/or regulatory genes involved in adhesion and/or piliation which are prerequisites in the S. entomophila-grass grub interaction leading to amber disease.     

A novel approach to the establishment of dual cultures of pearl millet and Sclerospora graminicola

Dual cultures were successfully established using malformed florets of pearl millet infected with Sclerospora graminicola, the downy mildew pathogen. A higher proportion (86%) of calli from malformed florets formed dual cultures on Murashige and Skoog's (MS) medium with 2 mg 1^-1 of 2,4-dichlorophenoxy acetic acid (2,4-d), compared to shoot tips (25%). Fungal mycelium covered the entire surface of the callus within 30 days of placement of explants on the MS medium with 2 mg 1^-1 of 2,4-d. The infected calli also differentiated and produced plantlets when transferred to MS medium without 2,4-d.     

Biochemical diversity evaluation in chickpea accessions employing mini-core collection

The seeds of chickpea provide an exceptional source of dietary proteins and is one of the important legumes in both developed and developing countries over the world. The available germplasm of cultivated chickpea is deficient in desired biochemical signatures. To identify new sources of variations for breeding, reduced subsets of germplasm such as mini-core collection can be explored as an effective resource. In the present investigation, mini-core collections consisting of 215 accessions of chickpea were extensively evaluated for tapping biochemical diversity. Analysis included ten biochemical parameters comprising total protein, total free amino acids, phytic acid, tannin, total phenolics, total flavonoids, lectin, DPPH radical scavenging activity, in vitro digestibility of protein and starch. The spectrum of diversity was documented for total protein (4.60–33.90%), total free amino acids (0.092–9.33 mg/g), phytic acid (0.009–4.06 mg/g), tannin (0.232–189.63 mg/g), total phenolics (0.15–0.81 mg/g), total flavonoids (0.04–1.57 mg/g), lectin (0.07–330.32 HU/mg), DPPH radical scavenging activity (26.74–49.11%), in vitro protein digestibility (59.45–76.22%) and in vitro starch digestibility (45.63–298.39 mg of maltose/g). The principal component analysis revealed association of chickpea higher protein content to the lower level of total phenolics and flavonoid contents. The dendrogram obtained by unweighted pair group method using arithmetic average cluster analysis grouped the chickpea accessions into two major clusters. This is the first comprehensive report on biochemical diversity analysed in the mini-core chickpea accessions. The ultimate purpose of conducting such studies was to deliver information on nutritional characteristics for effective breeding programmes. Depending on the objectives of the breeding aforesaid accessions could be employed as a parent.     

Decreasing mortality and hospitalizations with rising costs related to gastric cancer in the USA: an epidemiological perspective

Background

There is no convincing data on the trends of hospitalizations, mortality, cost, and demographic variations associated with inpatient admissions for gastric cancer in the USA. The aim of this study was to use a national database of US hospitals to evaluate the trends associated with gastric cancer.

Methods

We analyzed the National Inpatient Sample (NIS) database for all patients in whom gastric cancer (ICD-9 code: 151.0, 151.1, 151.2, 151.3, 151.4, 151.5, 151.6, 151.8, 151.9) was the principal discharge diagnosis during the period, 2003–2014. The NIS is the largest publicly available all-payer inpatient care database in the US. It contains data from approximately eight million hospital stays each year. The statistical significance of the difference in the number of hospital discharges, length of stay, and hospital costs over the study period was determined by regression analysis.

Results

In 2003, there were 23,921 admissions with a principal discharge diagnosis of gastric cancer as compared to 21,540 in 2014 (P?<?0.01). The mean length of stay for gastric cancer decreased by 17% between 2003 and 2014 from 10.9?days to 8.95?days (P?<?0.01). However, during this period, the mean hospital charges increased significantly by 21% from $ 75,341 per patient in 2003 to $ 91,385 per patient in 2014 (P?<?0.001). There was a more significant reduction in mortality over a period of 11?years from 2428 (10.15%) in 2003 to 1345 (6.24%) in 2014 (P?<?0.01). The aggregate charges (i.e., “national bill”) for gastric cancer increased significantly from 1.79 bn $ to 1. 96 bn $ (P?<?0.001), despite decrease in hospitalization (inflation adjusted).

Conclusion

Although the number of inpatient admissions for gastric cancer have decreased over the past decade, the healthcare burden and cost related to it has increased significantly. Inpatient mortality is decreasing which is consistent with overall decrease in gastric cancer-related deaths. Cost increase associated with gastric cancer contributed significantly to the national healthcare bill.

     

Development of seed coat-imposed dormancy during seed maturation in Cynoglossum officinale

The relationship between seed phenolics and appearance of seed coat–imposed dormancy during seed development in Cynoglossum officinale L. was studied. Up to 24 days after anthesis, seeds failed to germinate upon imbibition in Petri dishes at 25°C. At 44 days after anthesis, seeds were fully germinable; removal of seed coats did not improve their germination or O₂ uptake. At 72 days after anthesis, mature seeds at the base of the cyme did not germinate unless their coats were removed. Removal of seed coat also stimulated O₂ uptake at this harvest date. The methanol-soluble phenolic content of the seeds increased during the early stages of seed development, in both the seed coat and the embryo. As seed development continued, the methanol-soluble phenolic content of the embryo stabilized, but that of the seed coat declined. This decline was associated with an increase in the thioglycolic acid–soluble phenolics, presumably lignins, in the seed coat. These results suggest that polymerization of methanol–soluble phenolics into lignins in the seed coat during later stages of seed development renders the seed coat of C. officinale impermeable to 03, and thus keeps the seed dormant.     

Characterization and significance of nine novel mutations in exon 16 of the neurofibromatosis type 1 (NF1) gene

Nine novel mutations have been characterized as the result of screening exon 16 of the human NF1 gene in 465 unrelated neurofibromatosis type 1 patients. These lesions include three nonsense and two missense mutations, two deletions, one duplication, and one mutation in the 5′ splice site of intron 16. Although exon 16 is the largest NF1 exon, no mutations have so far been reported in this region. This apparent paucity of lesions may be due either to a reduced functional importance of exon 16 or a screening bias or both. However, consideration of the mutability of exon 16 in comparison with other exons suggests that, at least for single base pair substitutions, no such factors need be invoked. Any previous lack of exon 16 mutations in this category would be explicable in terms of a lower propensity to mutate for codons in this gene region. Received: 1 November 1996 / Revised: 5 December 1996