Higher incidence of spontaneous sister-chromatid exchanges (SCEs) and X-ray-induced chromosome aberrations in peripheral blood lymphocytes during pregnancy

In vitro cultures of peripheral blood lymphocytes from human and muntjac (barking deer) females who were at an advanced stage of pregnancy (32-37 weeks pregnant women and 20-24 weeks pregnant muntjacs) showed an enhanced frequency of SCEs and X-ray-induced chromosome aberrations when compared with those of nonpregnant females. Lymphocyte cultures of nonpregnant females to which sex hormones progesterone, oestrogen and human chorionic gonadotropin (HCG) were added together exogenously also showed higher frequency of SCEs. The plausible reason(s) for such high incidence of SCEs during pregnancy is discussed.     

Influence of salt stress on biochemical processes in chickpea,Cicer arietinum L.

Summary Soybean plants were grown in pots with or without vesicular-arbuscular myocorrhizal (VAM) fungi in three soils of low plant-available P content, different texture and different water-holding capacities. Mineral nutrients, except P, were provided in a complete nutrient solution. The biomass of non-VAM plants was positively and fungal colonization negatively correlated with increasingly coarse soil texture. There was no correlation of soil P with host or endophyte growth. Plant growth enhancement was positively correlated with soil water content at −1.5 MPa. These observations suggest soil water status and the mycorrhizal condition interact in influencing plant growth.     

Platelet count on slow induction to high altitude

Platelet counts were estimated at sea level in 50 lowlanders. They were divided at random in two groups (A and B) of 25 each. Group A went up by train/road transport to 3658 m, while group B reached the same height after 8 days of acclimatisation enroute. Platelet counts were estimated serially in both groups at high altitude. Symptoms of high altitude exposure were also recorded. No significant change in the counts was noted in either group and none became Symptomatic. All were brought back to sea level by air and deinduction studies carried out on days 1 and 4 of return. The importance of these findings in the light of our existing knowledge is discussed.     

Molecular cloning and expression of Rhizobium fredii USDA 193 nodulation genes: extension of host range for nodulation.

DNA hybridization with the cloned nodulation region of Rhizobium meliloti as a probe revealed DNA homology with four HindIII fragments, 12.5, 6.8, 5.2, and 0.3 kilobases (kb) in size, of the symbiotic plasmid pRjaUSDA193. Both hybridization and complementation studies suggest that the common nodulation genes nodABC and nodD of R. fredii USDA 193 are present on the 5.2-kb HindIII and 2.8-kb EcoRI fragments, respectively, of the Sym plasmid. Both fragments together could confer nodulation ability on soybeans when present in Sym plasmid-cured (Sym-) and wild-type (Sym+) Rhizobium strains or in a Ti plasmid-cured Agrobacterium tumefaciens strain. Furthermore, the 2.8-kb EcoRI fragment alone was able to form nodulelike structures on Glycine max L. cv. "Peking" (soybean). Microscopic examination of these nodules revealed bacterial invasion of the cells, probably via root hair penetration. Bacterial strains harboring plasmids carrying the 5.2- and 2.8-kb nod fragments elicited root-hair-curling responses on infection. These data suggest that the genes responsible for host range determination and some of the early events of nodulation may be coded for by the 5.2-kb HindIII and 2.8-kb EcoRI fragments.     

Properties of a cellulolytic Sporolactobacillus and some non-sporing cellulolytic rods, presumptive clostridia, from an anaerobic digester

Anaerobic digesters contain a wide variety of anaerobic cellulolytic bacteria. Many of these are sporing rods. Some isolates from a mesophilic cattle waste anaerobic digester were classified as Sporolactobacillus spp. A further group of bacteria could not be induced to sporulate. In some respects they resembled Eubacterium , but considering all the properties it is suggested that they should be classified as a species of Clostridium.     

Synthesis, modification with N-acetoxy-2-acetylaminofluorene and physicochemical studies of DNA model compound d(TACGTA)

The deoxyhexanucleotide d(TACGTA) was synthesized by a modified phosphotriester method. The modified procedure made rapid synthesis of deoxyoligonucleotide possible in gram quantity. N-Acetoxy-2-acetylaminofluorene (AAAF) modified d(TACGTA). Thin layer chromatography and UV analysis of the acid treated AAF modified hexanucleotide showed that the covalent modification with AAF took place exclusively at C(8) of guanine in d(TACGTA). d(TACGTA) and AAF modified d(TACGTA) were purified by preparative high performance liquid chromatography (HPLC). The pure products were characterized by 1H and 31P-NMR. The circular dichroism (CD) spectrum of d(TACGTA) was consistent with DNA in the B form even in the presence of 4 M NaCl whereas the modified hexamer had nearly inverted spectrum in the absence of any added salt. Both NMR and CD analyses indicated profound alteration of conformation of d(TACGTA) upon covalent modification with AAF. The stabilization of the Z-like conformation in the modified hexamer under physiological conditions of salt and temperature suggests biological relevance.     

Relative DNA content in lymphocytes and buccal mucosa of patients with sex chromosomal anomalies

Cytophotometric estimation of DNA values from human buccal mucosa and lymphocyte culture nuclei shows a difference related to different X chromosomal abnormalities, namely, del X, XO, XXX and XXY. The values in the buccal mucosa in all cases except XXX were similar to the normal XX and XY. In lymphocytes nuclei, however, a steady increase in the DNA content at a significant level could be related to an increase in the number of X chromosomes. The similarity in the DNA values of normal XX and XY controls may be attributed to asynchrony in the replication patterns of X and Y chromosomes.