Genetic diversity analysis of fungal pathogen Bipolaris sorghicola infecting Sorghum bicolor in India.

Bipolaris sorghicola (Lefebvre and Sherwin) is a well known and economically important seed-borne pathogen with the specific species of sorghum (Sorghum bicolor [L] Moench) as host. Thirty-two strains were obtained from different geographical area of sorghum growing places in India. Molecular characterization using three marker systems i.e., universal rice primers (URP), inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) was carried out. Molecular marker work revealed differences along with geographical origin clustering of various B. sorghicola strains which could not be revealed through conventional method of characterization. Out of 13 URPs, 20 ISSR and 50 RAPD primers screened, 8 primers each from URP and ISSR, and 10 primers from RAPD marker were found to result in reproducible banding pattern. One hundred per cent of polymorphic bands was recorded in all three molecular markers. Total number of bands was recorded 1986 with average of 248.25 in URP marker, and 2026 bands with average of 253.25 in ISSR marker and 2158 bands with average of 215.80 in RAPD markers. Maximum heterozygosity (Hn) was revealed by URP 17R (0.40), ISSR 10 (0.41) and RAPD marker OPC-5 (0.34). The polymorphism information content (PIC) values ranged between 5.89 to 8.28 in URP, 4.57 to 8.79 in ISSR and 4.44 to 9.64 in RAPD marker profiles. Maximum cophenetic correlation was found in URP (r = 0.910) followed by ISSR (r = 0.904) and RAPD (r = 0.870). The combined analysis of all three marker systems showed high cophenetic correlation (r = 0.911), which indicated a very good fit of the data for genetic diversity analysis. To best of our knowledge, this is a first report of genetic characterization of B. sorghicola. Hence, combined use of three marker systems would be more sensitive and reliable in characterizing genetic variability in B. sorghicola strains.

Microbial keratitis after descemet stripping automated endothelial keratoplasty.

BACKGROUND: To report two cases of corneal infection after Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: Two eyes of two patients demonstrated varying clinical presentations of microbial keratitis after DSAEK. At the initial presentation, the keratitis involved the host cornea alone in case 1, whereas in case 2, the posterior lamellar disk alone was involved. A pair of microvitrectomy scissors was used in case 2 from the side port to obtain a 2-mm sample of the posterior lamellar disk for microbiologic evaluation. The keratitis did not respond to medical therapy, and therapeutic penetrating keratoplasty was performed to resolve the infection in both the eyes. The main outcome measures were resolution of infection, absence of recurrence of keratitis, graft clarity, and visual outcome. RESULTS: There was complete resolution of infection after full thickness therapeutic grafts with best-corrected visual acuities of 20/60 and 20/40, respectively. CONCLUSIONS: Initial presentation of microbial keratitis after DSAEK may involve either the host or the posterior lamellar disk alone. A microvitrectomy scissors through the side port may be used for biopsy of posterior lamellar disk in recalcitrant infection.

Optic disc oedema: a diagnostic dilemma.

The authors describe a patient who presented with bilateral disc oedema and left eye visual loss. The patient was evaluated for intracranial space occupying lesion, however, a CT and cerebrospinal tap was normal. No definitive diagnosis could be established and patient developed left eye optic atrophy which was thought to be post papilloedema atrophy. Six months later, the patient had similar visual loss in right eye and he was diagnosed as anterior ischemic optic atrophy (AION) by the ophthalmologist. The inferior altitudinal visual field loss, delayed visual evoked response and clinical picture supported the diagnosis. The patient was diagnosed with hypertension and type 2 diabetes and managed accordingly. All the symptoms, clinical findings, investigations supported the diagnosis of AION which occurred in left eye followed by right eye 6 months later. Appropriate treatment was started and patient regained vision in right eye.