KERATINS AND SKIN DISORDERS

The epidermal keratinocytes express two major pairs of keratin polypeptides. One pair (K5/K14) expressed specifically in basal generative compartment and the other (K1/K10) expressed specifically in the differentiating suprabasal compartment. The switch in the expression of the keratins from proliferating to differentiating compartment indicates the changes that occur in the keratin filament organization which in turn influences the functional properties of the epidermis. Proper regulation of keratin gene expression and the filament organization are absolutely necessary for normal functioning of the skin. Keratin gene mutations can influence the filament integrity thereby causing several heritable blistering disorders of the skin such as epidermolysis bullosa, bullous icthyosiform erythroderma, etc. Changes in the keratin gene expression may lead to incomplete differentiation of the epidermal keratinocyte, causing hyperproliferative diseases of the skin such as psoriasis, carcinomas, etc. This review briefly describes the changes in keratin structure or gene expression that are known to result in various disorders of the skin.     

CELL SURFACE LOCALIZATION OF THE 60 kDa HEAT SHOCK CHAPERONIN PROTEIN (hsp60) IN MAMMALIAN CELLS

To investigate whether the 60-kDa heat shock chaperonin protein (hsp60) is present on the surface of mammalian cells, we used immunogold labeling of intact cells and backscattered electron imaging to image gold particles. Chinese hamster ovary cells and the human leukemic CD4-positive T-cell line CEM-SS on glass coverslips were labeled using affinity-purified monoclonal and polyclonal antibodies specific for hsp60 and 30 nm gold markers. Cells were imaged using the scanning mode of the conventional transmission electron microscope. Backscattered electron imaging provided definitive identification of the gold markers while secondary electron imaging gave information on surface architecture. Labeling intensity was 250–800 gold particles per cell in Chinese hamster ovary cells and 600–2000 in CEM-SS human lymphoblasts. The finding of hsp60 on the cell surface of mammalian cells may signify chaperone involvement in surface functions.     

Trophic Ecology of Ansonia latidisca at Gunung Penrissen,Sarawak, North-Western Borneo

Dietary data on Ansonia latidisca, the little known Bornean Rainbow Toad, are presented, through an investigation of a population at Gunung Penrissen, Sarawak, ...     

Ringlike structures in fine needle aspirates from the breast

Spherical ringlike structures of various sizes resembling Liesegang rings (LRs) are described in four fine needle aspirates (FNAs) from breast lesions over a period of 13 years. A characteristic finding in these structures was a distinct double layer outer wall with striations and an amorphous central nidus. Under polarized light they were non-refractile and no birefringence was noted in Congo red. Immunohistochemical stains for calcium, iron, mucus, glycogen, amyloid, cytokeratin and epithelial membrane antigen in all the cases were found to be negative. Since LRs can be mistaken for ova or parasites, their presence in aspirates of breast should be kept in mind to avoid misdiagnosis.     

Production of Phytophthora infestans oospores in planta and inoculum potential of in vitro produced oospores under temperate highlands and subtropical plains of India

High moisture content of the host tissue ( 88%) and low ambient r.h. (50-54%) favoured oospore formation under controlled environments. It took 14–16 days for oospores to develop; thereafter the number of oospores increased with time and decreased with moisture content of host tissue. High ambient r.h. (> 80%) did not favour oospore formation under field or controlled conditions. Oospore formation was detected in inoculated plants grown in the field when the ambient r.h. declined to 74% and moisture content of host tissue decreased to 83.7–85.6%. It took 8 days (cv. Kufri Chandramukhi) to 13 days (cv. Kufri Jyoti and Kufri Badshah) for oospores to develop. Cultivars also differed in their response to oospore production, cv. Kufri Chandramukhi being more responsive (4800 oospores g⁻¹ f wt) than cv. Kufri Jyoti and Kufri Badshah (1320 and 390 oospores g⁻¹ f wt respectively). Oospores produced in vitro remained viable when buried in soil in the temperate highlands of Himachal Pradesh and sub-tropical plains of Uttar Pradesh, India for more than 150 days, i.e. beginning of the next crop season. The oospores germinated and initiated late blight infection at the base of the stems after 21–30 days of incubation of the potato plants raised in oospore-infested soil. It took 2 days for newly formed oospores to germinate and this delay time increased to 75–77 days after 180-days burial. It took 15 days for their germination (47%) in soil extract as compared to 50 days in sterilised distilled water.     

Development and use of anchored‐SSRs to study DNA polymorphism in bread wheat (Triticum aestivum L.)

In bread wheat, 21 anchored simple sequence repeat (SSR) primer pairs detecting SSR length polymorphism and 42 anchored SSR primers detecting microsatellite‐anchored fragment length polymorphisms (MFLPs) are reported. Eight bread wheat genotypes were used for detecting polymorphism. The number of alleles in SSR analysis ranged from two to six, with a mean of 2.9 alleles per SSR. The number of polymorphic bands in MFLP ranged from two to 40, with a mean of 12.74 polymorphic bands/primer combination, the SSRs with CT/GA motifs giving the highest level of polymorphism (a mean of 18.37 bands). The average value of polymorphic information content (PIC) was 0.473 for SSRs and 0.061 for MFLP.     

Photochemical Characteristics of Mesophyll and Bundle Sheath Chloroplasts from C4 Plants

Mesophyll and bundle sheath chloroplasts were isolated by differential grinding from the leaves of two NADP-ME C₄ plants, Setaria italica Beauv. cv. H-1, Pennisetum typhoides S & H. cv. AKP-2, and a NAD-ME C₄ species Amaranthus paniculatus L. The mesophyll chloroplasts of C₄ plants possessed slightly lower K_m for ADP and Pi than those of bundle sheath chloroplasts. The Hill reaction activities and noncyclic photophosphorylation rates of the bundle sheath chloropiasts from S. italica and P. typhoides were less than one-fifth of those by the mesophyll chloroplasts. But the bundle sheath chloroplasts of A. paniculatus exhibited high rates of Hill reaction, cyclic as well as noncyclic photophosphorylation. The pigment- and eyiochrome composition suggested a relative enrichment of PS 1 in bundle sheath chloroplasts of S. italica and P. typhoides. The chain exists in both mesophyll and bundle sheath chloroplasts. As much as 35–52% of leaf chlorophyll was located in the bundle sheath chloroplasts. The photochemical activities of bundle sheath chloroplasts are significant though a major part of leaf photochemical potential is associated with the mesophyll chloroplasts.